Title of Invention	A NOVEL PRE-STRESSED RAIL SLEEPER PARTICULARLY USEFUL FOR UNDERGROUND HAULAGE TRACK
Abstract	This invention describes a rail sleeper particularly useful for underground haulage track which consists of a pair of pre-stressed steel tie rods of circular section connected to accommodate a pair of C-shaped steel flats by welding to form a pair of D-shaped loop. The pair of D-shaped loop combination is connected to each other by two pairs of each rectangular steel flats by means of welding. Each of the rectangular steel flats has threaded hole within at the top ends. Both the bottom end of the D-shaped loop are welded with plurality of individual U-shaped steel wires to form a web, while the middle portion with a rectangular shaped steel rod. Folded wire nets being inserted inside the webs made by U-shaped wires. Both ends of the assembly being concretized in a suitable rectangular or tapezoidal shaped. Means for fixing rails are also provided. This sleeper provides for higher load capacity, prolong life-expediency, inert with the ballast material, easy to manufacture as well as maintenance, cheaper and eco-friendly in nature in comparison to other concrete sleeper.

Title of Invention

A NOVEL PRE-STRESSED RAIL SLEEPER PARTICULARLY USEFUL FOR UNDERGROUND HAULAGE TRACK

Abstract

This invention describes a rail sleeper particularly useful for underground haulage track which consists of a pair of pre-stressed steel tie rods of circular section connected to accommodate a pair of C-shaped steel flats by welding to form a pair of D-shaped loop. The pair of D-shaped loop combination is connected to each other by two pairs of each rectangular steel flats by means of welding. Each of the rectangular steel flats has threaded hole within at the top ends. Both the bottom end of the D-shaped loop are welded with plurality of individual U-shaped steel wires to form a web, while the middle portion with a rectangular shaped steel rod. Folded wire nets being inserted inside the webs made by U-shaped wires. Both ends of the assembly being concretized in a suitable rectangular or tapezoidal shaped. Means for fixing rails are also provided. This sleeper provides for higher load capacity, prolong life-expediency, inert with the ballast material, easy to manufacture as well as maintenance, cheaper and eco-friendly in nature in comparison to other concrete sleeper.

Full Text	The present invention relates to a novel pre-stressed rail sleeper particularly useful for underground haulage track. The present invention is applicable to wide range of load application exerted in underground haulage track rail sleeper. It provides more strength, which results into keeping a pair of rails in a particular distance used for haulage tracks for tub or mine car movement in a mine / tunnel. The present invention provides a novel sleeper for reinforcing a haulage track in a mine. This sleeper will be able to hold the track rails in a predetermined distance when used in mine/ tunnel haulage roads, which may be laid over the ballast as available inside the mine/tunnel. The novel sleeper of the present invention will be capable of holding the track as per design, into a previously made mine haulage road in underground or even in surface and thereby ensure a uniform track gauge distance. It is well known that various kinds of sleepers are used to keep the rails of a haulage track as per the predetermined design of track. These sleepers that may be wooden, concrete or reinforced concrete slabs that serves the basis for design and the support mechanism of any haulage or transportation tracks in the mine as well as in the surface which is laid over an evenly laid ballast to provide an uniform load distribution over the ground. Extensive efforts have been made to the development of various sleeper devices for tracks of surface as well as for underground mine. To highlight the wide mining and tunneling usage and continual efforts, which have been made by other inventors to improve the performance of sleepers, a few patent references are provided below for illustration. A lot of inventions have been made in this arena but those are clumsy and cost ineffective in the context of installation as well as operation. Some related inventions are discussed below along with their drawbacks at length. Reference may be made to US patent No. US 6,230,981 entitled as "Steel railroad sleepers". The excerpt of this invention is given below: Abstract: A steel railroad sleeper of inverted channel section whose open ends can selectively be closed by end plates detachably connected one to open end of the sleeper and whose sides incline downwardly and outwardly from the upper rail supporting surface of the sleeper, the sleeper being produced by cold forming strip steel. The sleeper may be produced by cold pressing or cold rolling and the end plates may also be produced by cold forming steel strip. In one embodiment the sleeper has a waisted section of reduced width. This waisted section may be positioned generally midway along the length of the sleeper. The central section of the sleeper interior may be filled with a material to prevent the ingress of ballast to this central region. The main disadvantages of this invention being: it is very heavy being made ofl concrete, difficult to manufacture, ends are elongated upwardly and difficult to maneuver. Reference may be made to U.S. patent no. 6,581,848 titled 'Sleeper frame for a rail system for rail-mounted vehicles, especially for a ballasted track'. The synopsis of this invention is given below: Abstract: The invention relates to a sleeper frame for a track system for railborne vehicles, particularly for a ballasted track, consisting of several cross-ties provided in the direction transverse to the track, and one or several longitudinal supports connected with the cross-ties, wherein one cross-tie, respectively, substantially forms the outer delimitation of the sleeper frame in the longitudinal direction, with outer bearings and fixtures for the rails being provided on the outer cross-ties, and with a continuous or quasi-continuous bearing for the rails being provided between the outer rail bearings. The main disadvantage of this system is that it is costly and complicated. It is to be used generally for permanent type railway track but in mine haulage system the tracks are temporary and only for transporting the muck generated in construction and some other mining materials. Thus this invention will make it heavier and difficulty in transportation and installation of these sleepers in underground mine. Reference may be made to EU patent no. WO2006069553 titled 'Concrete sleeper and method for the production thereof as shown in figure 1 of the drawings accompanying this specification. The synopsis of this invention is given below: Abstract: Disclosed is a concrete sleeper for great dynamic loads with rail supporting areas (2) and a lower base zone. Said concrete sleeper is made of a high-strength standard concrete (4) that absorbs great pressure. The rail supporting areas (2) and/or the lower base zone is/are made of a wear-resistant, non-abrasive, or tension-proof material. The main disadvantages of this invention are: it is heavy being made of concrete, heavier, difficult to manufacture, ends are elongated upwardly and difficult to maneuver. Reference may be made to U.S. patent no. 6,070,806 titled 'Sleeper'. The synopsis of this invention is given below: Abstract: The sleeper (tie) comprises a body which has a variable cross section along its length and is made from reinforced polymer concrete with a dispersed reinforcement in the form of steel or synthetic fibres or both the one and the other together, which fibres compose 5-7% of the total mass of the body of the sleeper, are of different length and have a different percent of content depending on the type of fibre. At the points of fastening the rails, inserts are provided in the body, the height of the inserts satisfying the relationship: 2/3 H.sub.1 .gtoreq.H.sub.2 1/3 H.sub.1, where H.sub.1 is the height of the highest portion at each end of the body of the sleeper, H.sub.2 is the height of the insert. The upper face of the middle part of the body is positioned higher than the lower face of the insert by a value .DELTA.H which is within the limits 0.5(H.sub.1 -H.sub.2).DELTA.H0.1(H,sub.1 -H.sub.2). Metallic and wooden inserts of various geometric shape are used. The main disadvantages of this invention is: it is of fibre material, metallic and wooden inserts makes it difficult to manufacture and permanent nature which does not suggest frequent replacement as required in mine haulage system. And it is also difficult to maneuver. Reference may be made to U.S. patent no. 6,595,434 titled 'Rail bounded transport system'. The gist of this invention is given below: Abstract: Track-bound transport systems have existed for a long time. The drawback with them is that they can only withstand low load and are vulnerable in varying weather conditions. The purpose of the invention is to considerably increase the load they are capable of supporting and to reduce dependence on changes in weather. Thus this invention is applicable to low load and vulnerable to weather makes it unsuitable to mine haulage system. Moreover highly skilled labour is required to install these sleepers. Reference may be made to U.S. patent no. 4,946,099 titled 'Sleeper construction'. The gist of this invention is given below: Abstract: A concrete sleeper has an elongate metal insert having a T-slot containing a T-head of a retaining block which bears against a rail foot to retain rail gauge. The retaining block can be rotated by 180.degree. and slid along the T-slot to abut an edge of the foot of a rail, the T-slot being sufficiently long to allow adjustment of the rail on the sleeper. After rail position has been determined, Hie block location can be fixed by inserting grout into the T- slot. Alternatively, the T-slot can have abutment lugs which determine the block position, and thereby the rail position. The main disadvantages of this invention is: it is heavy due to retaining block, difficult to manufacture, and also difficult to maneuver. Reference may be made to European patent no. RU2250279 entitled 'Reinforced concrete under rail base and method of its construction1. Abstract: FIELD: railway transport; permanent way. * SUBSTANCE: invention relates to permanent way designed to take up load from rolling stock. Frame base consists of reinforced concrete frame ties placed in row on crushed stone ballast layer. Each tie is made of reinforced rigidly interconnected two longitudinal (sleeper) parts and two cross-members forming rectangular frame with hollow middle part with trapezoidal section projections with under-rail pads in places of connection of longitudinal parts. Cross-members of frame tie are rigidly connected with longitudinal parts by inner faces of longitudinal parts at right angle, and outer face of longitudinal part of each frame tie has smooth surface. Shaped cutouts are made on cross-members of each frame two sides. Cutouts on inner side are used to form space in inner part of tie in form of cell, and those on outer side, to form cell between adjacent frame ties equal to inner cell. Rail fastenings of adjacent frame ties are arranged at constant pitch equal to distance between axes of frame cross-members. At approaches to bridges, tunnels and overhead roads, reinforced concrete frames are laid in cross-members of which over their entire length and flush with upper surface tubular rectangular section parts are imbedded to which "shuttle-like" joint ends of counter-rails or counter-angles are fastened by means of bolts with T-head through holes of corresponding shape made in place of fastening. Method of construction of under-rail base comes to the following: frame ties are placed on ballast layer with clearance between adjacent frames to provide free access to ballast layer for tamping mechanisms from outside and inside of longitudinal parts of reinforced concrete frames. Clearance is found from following equation: H=0.5B where H is value of clearance; B is width of cell between cross-members inside each frame. Rail fastenings of adjacent frame ties are installed at constant pitch equal to distance between axes of frame crass-members. EFFECT: reduced labor input and volume of work, improved stability of rail track, reduced expenses possibility of laying "shuttle-like" joined ends of counter-rails of counter-angles at approaches to bridges, tunnels. The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine or a tunnel. Reference may be made to European patent no. DE102004008357 entitled 'Rail track for rail vehicles comprises several sleepers arranged in the longitudinal direction of the track and extending in the longitudinal direction of the sleeper across the longitudinal direction of the track' as shown in figure 2 of the drawings accompanying this specification. The gist of the invention is given below: Abstract; Rail track (10) comprises several sleepers (18) arranged in the longitudinal direction of the track and extending in the longitudinal direction of the sleeper across the longitudinal direction of the track. The sleepers are anchored on a support (20). The sleepers have two rail fixing regions (26, 28) arranged at a distance from each other in the longitudinal direction of the sleeper. - Preferred Features: The support is made from concrete, asphalt or similar material. The main disadvantage of this invention is that it is not cost effective for mine operators and may create uneven inter-track spacing. Reference may be made to US no. 4,802,623 entitled 'Concrete cross sleeper system'. The gist of the invention is given below: Abstract: Modern D.C.-tractioned trains and track circuit signal systems as well as high load trains need a special track construction. A new concrete cross sleeper system is provided for high load and high velocity tracks as well as for urban rapid transit systems comprising rails and sleepers having center part, connected to bar shaped ends and having reinforcing means. On the bar shaped ends two rail seats for each rail are positioned having elastic, electrically non-conducting plastic pads. The rails are fastened onto the rail seat by special tension means clamping the foot of the rail and fixed into plugs in the sleepers. This feature allows a triple point fixing of the rail at each sleeper end. Tracks on asphalt pavement may be secured by anchor device of the general type as sold under the trademark NELSON. The new track construction decreases the intermittent load of the rail/sleeper system and avoids trouble in track circuit signal systems existing in normally used prestressed concrete sleepers. The main disadvantage of this system is that it is costly, uses a lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine or a tunnel. Reference may be made to European patent no. GB1165168 entitled 'Improvement in railway track sleepers' as shown in figure 3 of the drawings accompanying this specification. Abstract: 1,165,168. Railway sleepers. POOR & CO. 28 Nov., 1966, No. 53236/66. Heading E1G. A moulded synthetic resin sleeper has a railreceiving plate P embedded in its surface by means of keying apertures 13. Recesses 14 are provided for rail-fastening members. The sleeper may be reinforced by metal or glass fibre rods extending between transverse plates, and its undersurface may be provided with a channel or rib. This invention consisting of a moulded synthetic resin sleeper has a rail receiving plate embedded in its surface by means of keying apertures. Recesses are provided for rail-fastening members. The sleeper may be reinforced by metal or glass fibre rods extending between transverse plates, and its undersurface may be provided with a channel or rib. The main disadvantage of this type of sleeper is in its manufacture. It does not mention about the weight of the sleeper or its transportability. Reference may be made to US patent no. 4,452,392 entitled 'Rail spring clip fastening assembly. The gist of the invention is given below: Abstract: Improved rail fastening assembly consisting of a clip and an insert or retaining member, the clip being made from a spring steel rod and comprising an elongated rail pressing toe member, each end whereof is bent upwardly to form a first curved portion, referred to as toe curve of generally inverted U shape and disposed in vertical plane, the rod being further bent downwardly to form a second curved portion of generally U shape in the same vertical plane, the ends of said second curved portions being then bent outwardly to form third curved portions being the heel curves and extending into heel legs at a tangent to the said heel curves, the insert having a fulcrumming pin for second curved portions and a pin which is constrained to be inserted between a shoulder of the insert and the heel curves. The main disadvantage of this system is that it is a fastening device which does not solve the purpose of rail sleeper for mine haulage system Reference may be made to European patent no JP2006045920 entitled 'Steeper' as shown in figure 4 of the drawings accompanying this specification. The synopsis of the invention is given below: Abstract: PROBLEM TO BE SOLVED: To provide a sleeper increasing lateral shift resistant force ( ballast lateral drag force) of the track and reducing frequency of correction works of the tracks and depressing the material cost lessening the use quantity of law materials requiring no necessary excessive works when laying down sleepers. SOLUTION: In a sleeper 1, a urethane resin or unsaturated polyester resin is integrally formed by a long grass fiber reinforced thermosetting resin cellular material impregnated with long grass fibers and a recessed groove 2 is formed in the longitudinal direction of the lower face, and semicylindrical protrusions 3-5 are protruded, the protrusions 3-5 are arranged in the laterally middle center of the recessed groove 2 with the same intervals in the longitudinal direction. The height is formed higher than the depth of the recessed groove 2, by forming the protrusions 3-5, the ballast lateral friction force at the time when they are laid on the ballast road bed is increased. The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine. Reference may be made to US patent no. 4,448,349 entitled 'Rail sleepers with rail clamping devices. The synopsis of the invention is given below: Abstract: There is disclosed a rail sleeper which when secured to rails affords rapid disengagement when necessary and is comprised of a metal bar of a U-shaped channel section. At two locations along the length of the bar portions of flanges of the sleeper are removed to provide slots disposed at right angles to the longitudinal axis of the bar. Each slot is wider than the base of the rail fitting thereinto with the space between slots dependent upon the gage between parallel rails and with the depth of such slots being varied to suit rail height. One rail flange is secured in place by an overhanging portion of the sleeper flanges. The other rail flange is secured by a generally T-shaped steel plate which is bolted to the bottom of the U-shaped channel section such that the horizontal bar of the T-shaped plate rests across the upright flanges of the sleeper. One edge of the horizontal bar engages the web of the rail and the other edge engages the edge of the slot, thus wedging the rail into secure engagement. The main disadvantage of this system is that it is costly, difficult to manufacture, difficulty in transportation of these sleepers in underground mine. Replacement is also not suitable as required in mines. Reference may be made to European patent no. GB1204914 entitled 'Improvements connected with the building of railway tracks' as shown in figure 5 of the drawings accompanying this specification. The synopsis of the invention is given below: Abstract: 1,204,914. Portable railway track. SWEDISH RAIL SYSTEM A.B. 5 Oct., 1967, No. 45474/67. Heading F1G. A prefabricated rail-plus-sleepers element for a portable railway track (e.g. for travelling cranes) comprises a single short straight or curved rail 1 having sleeper blocks 2 attached thereto (e.g. by wedges 3 driven through cramps cast in the sleeper blocks). On site the elements are connected in pairs by one or more tie rods 4, adjacent pairs being connected end to end (e.g. by embracing projections 6). Each tie rod may be clamped to a rail or a concrete, wooden or iron sleeper block and may comprise two telescopic, screw-threaded or flange-bolted parts whereby its length can be changed.The main disadvantage of this invention is that the track may buckle causing derailment of the tubs/ mine car/ wagon. Reference may be made to US patent no. 4,417,690 entitled 'Steel railroad sleeper'. The synopsis of the invention is given below: Abstract: A steel railway sleeper has side walls and an upper wall, the upper wall having two pairs of upwardly formed protuberances, the protuberances of each pair forming respective rail retaining recesses which will hold rails correct to gauge, provide an upstand to which the stud is to be welded thereby reducing stud length, and provide a platform on which the spring clip can be positioned when the rails are assembled to the sleeper. The main disadvantage of this invention is that the track may buckle causing derailment of the tubs/ mine car/ wagon. Due to spring clip it may create lot of problem during replacement. Reference may be made to US patent no. 4,265,400 entitled 'Concrete sleeper for track circuitry'. The synopsis of the invention is given below: Abstract: A concrete sleeper for track systems incorporating electrical circuitry, in which sleeper electrically conducting cables are embedded, and therefore concealed therein, with an assembly to allow electrical connection between the cables and associated tracks and associated track side circuitry. In order to obtain connection to the track side circuitry a recess is provided in one end of the sleeper and receives a terminal box having contacts for contacting exposed ends of the embedded cables and connections within the terminal box are in turn connected to the track side circuitry. In order to achieve an electrical connection with the tracks the cables are connected, within the sleeper, to embedded parts of shoulders of rail fastening assemblies of the type marketed under the name PANDROL The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine. Reference may be made to US patent no. 4,098,460 entitled 'Concrete unit prestressed using tendons stressed before concreting, more particularly a railway sleeper'. The synopsis of the invention is given below: Abstract: A long concrete unit, prestressed by tendons tensioned before concreting, at least one section of which, near the end of the said unit, is submitted to maximum loads, characterized by the fact that at least one improved-bond prestressing tendon is surrounded by spirals located on either side of the zone of maximum tensile stress. The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine. Reference may be made to European patent no. CA2528050 entitled Track structure for rail borne vehicles, particularly trains' as shown in figure 6 of the drawings accompanying this specification. The gist of the invention is given below: Abstract: Disclosed is a track structure for railborne vehicles, particularly trains, comprising a bed on which rails (1, 2) rest that are fixed to sleepers (3). Said track structure is characterized in that the bed consists of a concrete trough (4) that rests on a substructure (5) and is provided with sidewalls (4a, 4b) which extend in a longitudinal direction and are located parallel t o each other at a distance corresponding at least to the sleeper length L The main disadvantage is that it is not possible to use such system in underground haulage tracks due to its heavy structure and difficulty in transportation. Reference may be made to European patent no. EP1640498 entitled 'Sleeper assembly and railroad switch' as shown in figure 7 of the drawings accompanying this specification. Abstract: The sleeper connector block (1) is made of concrete and has at least two sleeper parts (3) which are connected to one another in a piece and between them form a drive pocket (5) for the parts of the points-interlocking. The drive pocket when built in is bordered underneath by a base plate (4) connected to the sleeper part which forms a smooth laying surface facing the track bed. The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine or a tunnel. Hence, it is clear from the hitherto known prior art that there is a definite need to provide a sleeper, which can easily and reliably ensure a proper reinforcing and supporting of the mine/tunnel haulage track system. The main object of the present invention is to provide a novel pre-stressed rail sleeper particularly useful for underground haulage track, which obviates the drawbacks of the hitherto known prior art as detailed herein above. Another object of the present invention is to provide a sleeper which not only supports a pair of rail tracks for smooth functioning of mine / tunnel haulage system but also strengthens other sleepers in the haulage track. Yet another object of the present invention is to provide guarantee for holding the pair of rails at a uniform predetermined distance/spacing which is placed over a layer of ballast of a particular thickness. Still another object of the present invention is to provide a sleeper which has nominal chemical reaction with the ballast materials which provides security for prolong utility of the sleeper. Still yet another object of the present invention is to provide an eco-friendly sleeper which meets the scarcity of wooden sleepers due to uncontrolled deforestation. A further object of the present invention is to provide a reusable sleeper in terms of prolong life expediency. A still further object of the present invention is to provide a sleeper which provides better contact / bonding strength between the rails and the sleepers. A yet further object of the present invention is to provide a sleeper which equips uniform inter-track distance/alignment of the rails which provides smooth motion of mine cars/tubs on the track. Another object of the present invention is to provide a simple designed sleeper which is easily, cheaply and reliably manufactured as well as installed using the same prevailing techniques. Still another object of the present invention is to provide a sleeper which can check the chances of stealing in comparison to wooden sleeper which is prevalently used as fire wood. Yet another object of the present invention is to provide a sleeper which is easily maneuverable & transportable to and from the mine. Still yet another object of the present invention is to provide a sleeper which requires less maintenance cost of track. A further object of the present invention is to provide a sleeper which is useful for reinforcing mine track having simple design, light weight, easy to manufacture, cheap & easy installation procedure and easy to handle which obviates the drawbacks of the above noted hitherto known prior art. The present invention consists of a pair of C-shaped flats of rectangular section which is welded with a pair of pre-stressed steel tie rods of circular section with suitable diameter which forms a D-shaped loop. A pair of D-shaped loop combination is connected to each other by two pairs of each rectangular steel flats by means of welding which has threaded hole within at the top ends. Both the bottom end of the D-shaped loop are welded with the plurality of individual U-shaped steel wires forming a web, whilst the middle portion is a rectangular shaped steel rod. A folded wire net of suitable size is inserted inside the webs made by U-shaped wires at the bottom portion of the D-shaped loop. Both the end of the assembly is concretized in a suitable rectangular shaped slab which contains the portion of C-shaped steel flat, tie rods, and full of steel flats, U-shaped net and web inside the slab. Two pairs of nuts and cleats each having a hole within is fixed upon both the concrete slabs by means of threaded hole with the steel flats. This sleeper is easy to manufacture, install and maintenance which makes it cheaper and eco-friendly in nature due to prevent deforestation in comparison to other concrete sleeper. In figures 8 to 11 of the drawings accompanying this specification an embodiment of the sleeper of the present invention for reinforcement of a haulage track in a mine is illustrated. In the embodiment of this invention, as shown in figures 8 to 11 of the drawings, it reveals that it contains a pair of C-shaped flats (3) of rectangular section. A pair of steel tie rods (2) of circular section with suitable diameter is welded in pre-stressed condition to accommodate the steel flats (3) which forms a D-shaped loop (2,3). A pair of D-shaped loop combination (2 & 3) is connected to each other by two pairs of each rectangular steel flats (7) by means of welding. Each rectangular steel flats (7) has threaded hole within at the top ends. Both the bottom end of the D-shaped loop are welded with the plurality of individual U-shaped steel wires forming a web (8), while the middle portion is welded with a rectangular shaped steel rod frame (5). A folded wire net (9) of suitable size is inserted inside the steel wire webs (8) made by U-shaped wires at the bottom portion of (3). Both the end of the assembly (2, 3, 5, 7, 8 & 9) is concretized in a suitable rectangular shaped slab which encloses a portion of 2 & 3, and full of 7, 8 & 9 inside the slab. Two pairs of nuts (6) and cleats (4) each having a hole within is fixed upon both the concrete slabs (1) by means of threaded hole with the steel flats (7). Accordingly the present invention provides a novel pre-stressed rail sleeper particularly useful for underground haulage track, which comprises: a pair of D-shaped loop (2,3) consisting of a pair of C-shaped flats (3) being connected by means, such as welding, to a pair of steel rods (2), the said pair of D-shaped loop (2 & 3) being connected to each other at the top ends by means of two pairs of rectangular steel flats (7) having threaded hole within, at the bottom ends by means of a plurality of U-shaped steel wires (8), and in the middle by a rectangular shaped steel rod frame (5), in the inside of the webs (8) made by U-shaped wires at the bottom portions of (3) being inserted at both ends folded wire net (9); the ends of said assembly (2, 3, 5, 7, 8 & 9) being concretized to form slabs (1) at both ends which encloses the said steel flats (7), U-shaped steel wires (8) and folded wire nets (9) and the end portions of the said D-shaped loops (2,3); on the top of the said concrete slabs (1) being provided means for fixing rails, such as cleats (4) fixed by means of nuts (6) to the threaded hole of each of the said flats (7). In an embodiment of the present invention, the C-shaped flats (3) are of rectangular section. In another embodiment of the present invention, the steel rods (2) are of circular section. In still another embodiment of the present invention, the pair of D-shaped loop (2,3) consisting of a pair of C-shaped flats (3) being connected by means, such as welding, to a pair of steel rods (2) kept in pre-stressed condition. In yet another embodiment of the present invention, the pair of D-shaped loop (2 & 3) being connected to each other at the top ends by means of two pairs of rectangular steel flats (7) having threaded hole within, at the bottom ends by means of a plurality of U-shaped steel wires (8), and in the middle by a rectangular shaped steel rod frame (5), all by the method of welding with the body of pair of D-shaped closed loops (2,3). In still yet another embodiment of the present invention, the means for fixing rails, such as cleats (4) is replaced by spring clip system. In a further embodiment of the present invention, the ends of said assembly (2, 3, 5, 7, 8 & 9) being concretized to form slabs (1), such as of rectangular, trapezoidal cross-section. The main novelty of the present invention is to provide a pre-stressed rail sleeper particularly useful for underground haulage track which obviates the drawbacks of the hitherto known prior art as detailed above. Another novelty of the present invention is to provide a sleeper which not only supports a pair of rail tracks for smooth functioning of mine / tunnel haulage system but also strengthens other sleepers in the haulage track. Yet another novelty of the present invention is to provide guarantee for holding the pair of rails at a uniform predetermined distance/spacing which is placed over a layer of ballast of a particular thickness. Still another novelty of the present invention is to provide a steeper which has nominal chemical reaction with the ballast materials which provides security for prolong utility of the sleeper. Still yet novelty object of the present invention is to provide an eco-friendly sleeper which meets the scarcity of wooden sleepers due to uncontrolled deforestation. A further novelty of the present invention is to provide a reusable sleeper in terms of prolong life expediency. A still further novelty of the present invention is to provide a steeper which provides better contact / bonding strength between the rails and the sleepers. A yet further novelty of the present invention is to provide a sleeper which equips uniform inter-track distance/alignment of the rails which provides smooth motion of mine cars/tubs on the track. Another novelty of the present invention is to provide a simple designed sleeper which is easily, cheaply and reliably manufactured as well as installed using the same prevailing techniques. Still another novelty of the present invention is to provide a sleeper which can check the chances of stealing in comparison to wooden sleeper which is prevalently used as fire wood. Yet another novelty of the present invention is to provide a sleeper which is easily maneuverable & transportable to and from the mine. Still yet another novelty of the present invention is to provide a sleeper which requires less maintenance cost of track. The non-obvious inventive steps of the novel pre-stressed rail sleeper particularly useful for underground haulage track, resides in the combination of the following: (a) It contains a pair of steel tie rods of circular section with suitable diameter welded under pre-stressed condition with a pair of C-shaped flats of rectangular section to form a D-shaped loop which sustains bending stress during dynamic loading. (b) It has plurality of individual U-shaped steel wires (web) for holding the concrete grout within the frame. (c) In the middle of the frame, a rectangular shaped steel rod is welded to provide stability in position and to provide hand hold facility for carrying purpose. (d) It has a folded wire net of suitable size which is inserted inside the webs for reinforcing the concrete structure to make it strong and stable. (e) It has suitable rectangular shaped concrete slabs structure at both ends for better absorption of shock loads on rails. (f) Rectangular shaped small concrete slabs at the ends in stead of full concretization of frame makes the sleeper lighter and economical. The following example is given by way of illustration of the working of the invention in actual practice and therefore should not be construed to limit the scope of the present invention. Example-1 A pre-stressed rail sleeper for supporting a haulage track in a mine was manufactured as detailed in the embodiment of the present invention in figures 8 to 11 of the drawings. A D-shaped loop (2,3) of 82 cm long was formed by welding a steel tie rod (2) of circular section having 10 mm thickness & length 52 cm in pre-stressed condition with a C-shaped flat (3) of rectangular section having 2cm width & 1cm thickness (pre-stressing is done by pressing the C-shaped flat inwardly through an external force suitably at the time of welding with the tie rod). A frame was fabricated by welding with a rectangular shaped 10mm steel rod (5) and a pair of rectangular steel flats (7) having size 75mmx15mmx12mm at each end. Distance between nearer rectangular steel flats (7) is 56mm while 76 mm for farther. Each rectangular steel flats (7) has threaded hole within at the top ends. Both the bottom end of the D-shaped loop are welded with the plurality of individual U-shaped steel wires (web) (8),. A folded suitable wire net (9) of suitable size is inserted inside the webs (8) made by U-shaped wires at the bottom portion of (3). Both the end of the assembly (2, 3, 5, 7, 8 & 9) is concretized in a suitable rectangular shaped slab which contains the portion of 2 & 3, and full of 7, 8 & 9 inside the slab. The dimension of concrete slab is 21mmx10.5mmx12mm. Two pairs of nuts (6) and cleats (4) each having a hole within is fixed upon both the concrete slabs (1) by means of threaded hole with the steel flats (7). The manufactured rail sleeper was subjected to compression test of slab. It was found that the concrete could withstand the pressure of 450 kg/sq cm. It was also thrown several times from a height of 2m to check the effect of impact load. It was found to be alright even after 10 times of free fall. The main advantages of the present invention for pre-stressed rail sleeper particularly useful for underground haulage track are: 1. It has nominal chemical reaction with the ballast materials which provides security for prolong utility of the sleeper. 2. Scarcity of wooden sleepers due to uncontrolled deforestation, it meets the requirements eco-friendly. 3. It can be reused due to prolong life expediency. 4. It can be easily, cheaply and reliably manufactured as well as installed using the same prevailing techniques due to simple design. 5. It equips uniform inter-track distance/alignment of the rails which provides smooth motion of mine cars/tubs on the track. 6. It provides better contact / bonding strength between the rails and the sleepers. 7. It checks the chances of stealing in comparison to wooden sleeper which is prevalently used as fire wood. 8. It is easy to transport inside/out side the mine. 9. It provides less maintenance cost of track. We claim: 1. A novel pre-stressed rail sleeper particularly useful for underground haulage track, which comprises: a pair of D-shaped loop (2,3) consisting of a pair of C-shaped flats (3) being connected by means, such as welding, to a pair of steel rods (2), the said pair of D-shaped loop (2 & 3) being connected to each other at the top ends by means of two pairs of rectangular steel flats (7) having threaded hole within, at the bottom ends by means of a plurality of U-shaped steel wires (8), and in the middle by a rectangular shaped steel rod frame (5), in the inside of the webs (8) made by U-shaped wires at the bottom portions of (3) being inserted at both ends folded wire net (9); the ends of said assembly (2, 3, 5, 7, 8 & 9) being concretized to form slabs (1) at both ends which encloses the said steel flats (7), U-shaped steel wires (8) and folded wire nets (9) and the end portions of the said D-shaped loops (2,3); on the top of the said concrete slabs (1) being provided means for fixing rails, such as cleats (4) fixed by means of nuts (6) to the threaded hole of each of the said flats (7). 2. A novel pre-stressed rail sleeper as claimed in claim 1, wherein the C- shaped flats (3) are of rectangular section. 3. A novel pre-stressed rail sleeper as claimed in claim 1-2, wherein the steel rods (2) are of circular section. 4. A novel pre-stressed rail sleeper as claimed in claim 1-3, wherein the pair of D-shaped loop (2,3) consisting of a pair of C-shaped flats (3) being connected by means, such as welding, to a pair of steel rods (2) kept in pre- stressed condition. 5. A novel pre-stressed rail sleeper as claimed in claim 1-4, wherein the pair of D-shaped loop (2 & 3) being connected to each other at the top ends by means of two pairs of rectangular steel flats (7) having threaded hole within, at the bottom ends by means of a plurality of U-shaped steel wires (8), and in the middle by a rectangular shaped steel rod frame (5), all by the method of welding with the body of pair of D-shaped closed loops (2,3). 6. A novel pre-stressed rail sleeper as claimed in claim 1-5, wherein the means for fixing rails, such as cleats (4) is replaced by spring clip system. 7. A novel pre-stressed rail sleeper as claimed in claim 1-6, wherein the ends of said assembly (2, 3, 5, 7, 8 & 9) being concretized to form slabs (1), such as of rectangular, trapezoidal cross-section. 8. A novel pre-stressed rail sleeper particularly useful for underground haulage track, substantially as herein described with reference to the example and figures 8 to 11 of the drawings accompanying this specification.

Full Text

The present invention relates to a novel pre-stressed rail sleeper particularly useful for underground haulage track. The present invention is applicable to wide range of load application exerted in underground haulage track rail sleeper. It provides more strength, which results into keeping a pair of rails in a particular distance used for haulage tracks for tub or mine car movement in a mine / tunnel.
The present invention provides a novel sleeper for reinforcing a haulage track in a mine. This sleeper will be able to hold the track rails in a predetermined distance when used in mine/ tunnel haulage roads, which may be laid over the ballast as available inside the mine/tunnel. The novel sleeper of the present invention will be capable of holding the track as per design, into a previously made mine haulage road in underground or even in surface and thereby ensure a uniform track gauge distance.
It is well known that various kinds of sleepers are used to keep the rails of a haulage track as per the predetermined design of track. These sleepers that may be wooden, concrete or reinforced concrete slabs that serves the basis for design and the support mechanism of any haulage or transportation tracks in the mine as well as in the surface which is laid over an evenly laid ballast to provide an uniform load distribution over the ground.
Extensive efforts have been made to the development of various sleeper devices for tracks of surface as well as for underground mine. To highlight the wide mining and tunneling usage and continual efforts, which have been made by other inventors to improve the performance of sleepers, a few patent references are provided below for illustration.
A lot of inventions have been made in this arena but those are clumsy and cost ineffective in the context of installation as well as operation. Some related inventions are discussed below along with their drawbacks at length.
Reference may be made to US patent No. US 6,230,981 entitled as "Steel railroad sleepers". The excerpt of this invention is given below:
Abstract: A steel railroad sleeper of inverted channel section whose open ends can selectively be closed by end plates detachably connected one to open end of the sleeper and whose sides incline downwardly and outwardly from the upper rail supporting surface of the sleeper, the sleeper being produced by cold forming strip steel. The sleeper may be produced by cold pressing or cold rolling and the end plates may also be produced by cold forming steel strip. In one embodiment the sleeper has a waisted section of reduced width. This waisted section may be positioned generally midway along the length of the sleeper. The central section of the sleeper interior may be filled with a material to prevent the ingress of ballast to this central region.
The main disadvantages of this invention being: it is very heavy being made ofl concrete, difficult to manufacture, ends are elongated upwardly and difficult to maneuver.
Reference may be made to U.S. patent no. 6,581,848 titled 'Sleeper frame for a rail system for rail-mounted vehicles, especially for a ballasted track'. The synopsis of this invention is given below:
Abstract: The invention relates to a sleeper frame for a track system for railborne vehicles, particularly for a ballasted track, consisting of several cross-ties provided in the direction transverse to the track, and one or several longitudinal supports connected with the cross-ties, wherein one cross-tie, respectively, substantially forms the outer delimitation of the sleeper frame in the longitudinal direction, with outer bearings and fixtures for the rails being provided on the outer cross-ties, and with a continuous or quasi-continuous bearing for the rails being provided between the outer rail bearings.
The main disadvantage of this system is that it is costly and complicated. It is to be used generally for permanent type railway track but in mine haulage system the tracks are temporary and only for transporting the muck generated in construction and some other mining materials. Thus this invention will make it heavier and difficulty in transportation and installation of these sleepers in underground mine.
Reference may be made to EU patent no. WO2006069553 titled 'Concrete sleeper and method for the production thereof as shown in figure 1 of the drawings accompanying this specification. The synopsis of this invention is given below:
Abstract: Disclosed is a concrete sleeper for great dynamic loads with rail supporting areas (2) and a lower base zone. Said concrete sleeper is made of a high-strength standard concrete (4) that absorbs great pressure. The rail supporting areas (2) and/or the lower base zone is/are made of a wear-resistant, non-abrasive, or tension-proof material.
The main disadvantages of this invention are: it is heavy being made of concrete, heavier, difficult to manufacture, ends are elongated upwardly and difficult to maneuver.
Reference may be made to U.S. patent no. 6,070,806 titled 'Sleeper'. The synopsis of this invention is given below:
Abstract: The sleeper (tie) comprises a body which has a variable cross section along its length and is made from reinforced polymer concrete with a dispersed reinforcement in the form of steel or synthetic fibres or both the one and the other together, which fibres compose 5-7% of the total mass of the body of the sleeper, are of different length and have a different percent of content depending on the type of fibre. At the points of fastening the rails, inserts are provided in the body, the height of the inserts satisfying the relationship: 2/3 H.sub.1 .gtoreq.H.sub.2 1/3 H.sub.1, where H.sub.1 is the height
of the highest portion at each end of the body of the sleeper, H.sub.2 is the height of the insert. The upper face of the middle part of the body is positioned higher than the lower face of the insert by a value .DELTA.H which is within the limits 0.5(H.sub.1 -H.sub.2).DELTA.H0.1(H,sub.1 -H.sub.2). Metallic and wooden inserts of various geometric shape are used.
The main disadvantages of this invention is: it is of fibre material, metallic and wooden inserts makes it difficult to manufacture and permanent nature which does not suggest frequent replacement as required in mine haulage system. And it is also difficult to maneuver.
Reference may be made to U.S. patent no. 6,595,434 titled 'Rail bounded transport system'. The gist of this invention is given below:
Abstract: Track-bound transport systems have existed for a long time. The drawback with them is that they can only withstand low load and are vulnerable in varying weather conditions. The purpose of the invention is to considerably increase the load they are capable of supporting and to reduce dependence on changes in weather.
Thus this invention is applicable to low load and vulnerable to weather makes it unsuitable to mine haulage system. Moreover highly skilled labour is required to install these sleepers.
Reference may be made to U.S. patent no. 4,946,099 titled 'Sleeper construction'. The gist of this invention is given below:
Abstract: A concrete sleeper has an elongate metal insert having a T-slot containing a T-head of a retaining block which bears against a rail foot to retain rail gauge. The retaining block can be rotated by 180.degree. and slid along the T-slot to abut an edge of the foot of a rail, the T-slot being sufficiently long to allow adjustment of the rail on the sleeper. After rail position has been determined, Hie block location can be fixed by inserting grout into the T-
slot. Alternatively, the T-slot can have abutment lugs which determine the block position, and thereby the rail position.
The main disadvantages of this invention is: it is heavy due to retaining block, difficult to manufacture, and also difficult to maneuver.
Reference may be made to European patent no. RU2250279 entitled 'Reinforced concrete under rail base and method of its construction1.
Abstract: FIELD: railway transport; permanent way. * SUBSTANCE: invention relates to permanent way designed to take up load from rolling stock. Frame base consists of reinforced concrete frame ties placed in row on crushed stone ballast layer. Each tie is made of reinforced rigidly interconnected two longitudinal (sleeper) parts and two cross-members forming rectangular frame with hollow middle part with trapezoidal section projections with under-rail pads in places of connection of longitudinal parts. Cross-members of frame tie are rigidly connected with longitudinal parts by inner faces of longitudinal parts at right angle, and outer face of longitudinal part of each frame tie has smooth surface. Shaped cutouts are made on cross-members of each frame two sides. Cutouts on inner side are used to form space in inner part of tie in form of cell, and those on outer side, to form cell between adjacent frame ties equal to inner cell. Rail fastenings of adjacent frame ties are arranged at constant pitch equal to distance between axes of frame cross-members. At approaches to bridges, tunnels and overhead roads, reinforced concrete frames are laid in cross-members of which over their entire length and flush with upper surface tubular rectangular section parts are imbedded to which "shuttle-like" joint ends of counter-rails or counter-angles are fastened by means of bolts with T-head through holes of corresponding shape made in place of fastening. Method of construction of under-rail base comes to the following: frame ties are placed on ballast layer with clearance between adjacent frames to provide free access to ballast layer for tamping mechanisms from outside and inside of longitudinal parts of reinforced concrete frames. Clearance is found from following equation: H=0.5B where H is value of clearance; B is width of cell between cross-members inside each frame. Rail fastenings of adjacent frame ties are installed at constant pitch equal to distance between axes of frame crass-members. EFFECT: reduced labor input and volume of work, improved stability of rail track, reduced expenses possibility of laying "shuttle-like" joined ends of counter-rails of counter-angles at approaches to bridges, tunnels.
The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine or a tunnel.
Reference may be made to European patent no. DE102004008357 entitled 'Rail track for rail vehicles comprises several sleepers arranged in the longitudinal direction of the track and extending in the longitudinal direction of the sleeper across the longitudinal direction of the track' as shown in figure 2 of the drawings accompanying this specification. The gist of the invention is given below:
Abstract; Rail track (10) comprises several sleepers (18) arranged in the longitudinal direction of the track and extending in the longitudinal direction of the sleeper across the longitudinal direction of the track. The sleepers are anchored on a support (20). The sleepers have two rail fixing regions (26, 28) arranged at a distance from each other in the longitudinal direction of the sleeper. - Preferred Features: The support is made from concrete, asphalt or similar material.
The main disadvantage of this invention is that it is not cost effective for mine operators and may create uneven inter-track spacing.
Reference may be made to US no. 4,802,623 entitled 'Concrete cross
sleeper system'. The gist of the invention is given below: Abstract: Modern D.C.-tractioned trains and track circuit signal systems as well as high load trains need a special track construction. A new concrete cross sleeper system is provided for high load and high velocity tracks as well as for urban rapid transit systems comprising rails and sleepers having center part, connected to bar shaped ends and having reinforcing means. On the bar shaped ends two rail seats for each rail are positioned having elastic, electrically non-conducting plastic pads. The rails are fastened onto the rail seat by special tension means clamping the foot of the rail and fixed into plugs in the sleepers. This feature allows a triple point fixing of the rail at each sleeper end. Tracks on asphalt pavement may be secured by anchor device of the general type
as sold under the trademark NELSON. The new track construction decreases the intermittent load of the rail/sleeper system and avoids trouble in track circuit signal systems existing in normally used prestressed concrete sleepers.
The main disadvantage of this system is that it is costly, uses a lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine or a tunnel.
Reference may be made to European patent no. GB1165168 entitled 'Improvement in railway track sleepers' as shown in figure 3 of the drawings accompanying this specification.
Abstract: 1,165,168. Railway sleepers. POOR & CO. 28 Nov., 1966, No. 53236/66. Heading E1G. A moulded synthetic resin sleeper has a railreceiving plate P embedded in its surface by means of keying apertures 13. Recesses 14 are provided for rail-fastening members. The sleeper may be reinforced by metal or glass fibre rods extending between transverse plates, and its undersurface may be provided with a channel or rib.
This invention consisting of a moulded synthetic resin sleeper has a rail receiving plate embedded in its surface by means of keying apertures. Recesses are provided for rail-fastening members. The sleeper may be reinforced by metal or glass fibre rods extending between transverse plates, and its undersurface may be provided with a channel or rib. The main disadvantage of this type of sleeper is in its manufacture. It does not mention about the weight of the sleeper or its transportability.
Reference may be made to US patent no. 4,452,392 entitled 'Rail spring clip fastening assembly. The gist of the invention is given below:
Abstract: Improved rail fastening assembly consisting of a clip and an insert or retaining member, the clip being made from a spring steel rod and comprising an elongated rail pressing toe member, each end whereof is bent upwardly to form a first curved portion, referred to as toe curve of generally
inverted U shape and disposed in vertical plane, the rod being further bent downwardly to form a second curved portion of generally U shape in the same vertical plane, the ends of said second curved portions being then bent outwardly to form third curved portions being the heel curves and extending into heel legs at a tangent to the said heel curves, the insert having a fulcrumming pin for second curved portions and a pin which is constrained to be inserted between a shoulder of the insert and the heel curves.
The main disadvantage of this system is that it is a fastening device which does not solve the purpose of rail sleeper for mine haulage system
Reference may be made to European patent no JP2006045920 entitled 'Steeper' as shown in figure 4 of the drawings accompanying this specification. The synopsis of the invention is given below: Abstract: PROBLEM TO BE SOLVED: To provide a sleeper increasing lateral shift resistant force ( ballast lateral drag force) of the track and reducing frequency of correction works of the tracks and depressing the material cost lessening the use quantity of law materials requiring no necessary excessive works when laying down sleepers.
SOLUTION: In a sleeper 1, a urethane resin or unsaturated polyester resin is integrally formed by a long grass fiber reinforced thermosetting resin cellular material impregnated with long grass fibers and a recessed groove 2 is formed in the longitudinal direction of the lower face, and semicylindrical protrusions 3-5 are protruded, the protrusions 3-5 are arranged in the laterally middle center of the recessed groove 2 with the same intervals in the longitudinal direction. The height is formed higher than the depth of the recessed groove 2, by forming the protrusions 3-5, the ballast lateral friction force at the time when they are laid on the ballast road bed is increased.
The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine.
Reference may be made to US patent no. 4,448,349 entitled 'Rail sleepers with rail clamping devices. The synopsis of the invention is given below:
Abstract: There is disclosed a rail sleeper which when secured to rails affords rapid disengagement when necessary and is comprised of a metal bar of a U-shaped channel section. At two locations along the length of the bar portions of flanges of the sleeper are removed to provide slots disposed at right angles to the longitudinal axis of the bar. Each slot is wider than the base of the rail fitting thereinto with the space between slots dependent upon the gage between parallel rails and with the depth of such slots being varied to suit rail height. One rail flange is secured in place by an overhanging portion of the sleeper flanges. The other rail flange is secured by a generally T-shaped steel plate which is bolted to the bottom of the U-shaped channel section such that the horizontal bar of the T-shaped plate rests across the upright flanges of the sleeper. One edge of the horizontal bar engages the web of the rail and the other edge engages the edge of the slot, thus wedging the rail into secure engagement.
The main disadvantage of this system is that it is costly, difficult to manufacture, difficulty in transportation of these sleepers in underground mine. Replacement is also not suitable as required in mines.
Reference may be made to European patent no. GB1204914 entitled 'Improvements connected with the building of railway tracks' as shown in figure 5 of the drawings accompanying this specification. The synopsis of the invention is given below:
Abstract: 1,204,914. Portable railway track. SWEDISH RAIL SYSTEM A.B. 5 Oct., 1967, No. 45474/67. Heading F1G. A prefabricated rail-plus-sleepers element for a portable railway track (e.g. for travelling cranes) comprises a single short straight or curved rail 1 having sleeper blocks 2 attached thereto (e.g. by wedges 3 driven through cramps cast in the sleeper blocks). On site the elements are connected in pairs by one or more tie rods 4, adjacent pairs being connected end to end (e.g. by embracing projections 6). Each tie rod may be clamped to a rail or a concrete, wooden or iron sleeper block and may comprise two telescopic, screw-threaded or flange-bolted parts whereby its length can be changed.The main disadvantage of this invention is that the track may buckle causing derailment of the tubs/ mine car/ wagon.
Reference may be made to US patent no. 4,417,690 entitled 'Steel railroad sleeper'. The synopsis of the invention is given below:
Abstract: A steel railway sleeper has side walls and an upper wall, the upper wall having two pairs of upwardly formed protuberances, the protuberances of each pair forming respective rail retaining recesses which will hold rails correct to gauge, provide an upstand to which the stud is to be welded thereby reducing stud length, and provide a platform on which the spring clip can be positioned when the rails are assembled to the sleeper.
The main disadvantage of this invention is that the track may buckle causing derailment of the tubs/ mine car/ wagon. Due to spring clip it may create lot of problem during replacement.
Reference may be made to US patent no. 4,265,400 entitled 'Concrete sleeper for track circuitry'. The synopsis of the invention is given below:
Abstract: A concrete sleeper for track systems incorporating electrical circuitry, in which sleeper electrically conducting cables are embedded, and therefore concealed therein, with an assembly to allow electrical connection between the cables and associated tracks and associated track side circuitry. In order to obtain connection to the track side circuitry a recess is provided in one end of the sleeper and receives a terminal box having contacts for contacting exposed ends of the embedded cables and connections within the terminal box are in turn connected to the track side circuitry. In order to achieve an electrical connection with the tracks the cables are connected, within the sleeper, to embedded parts of shoulders of rail fastening assemblies of the type marketed under the name PANDROL
The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine.
Reference may be made to US patent no. 4,098,460 entitled 'Concrete unit prestressed using tendons stressed before concreting, more particularly a railway sleeper'. The synopsis of the invention is given below:
Abstract: A long concrete unit, prestressed by tendons tensioned before concreting, at least one section of which, near the end of the said unit, is submitted to maximum loads, characterized by the fact that at least one improved-bond prestressing tendon is surrounded by spirals located on either side of the zone of maximum tensile stress.
The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine.
Reference may be made to European patent no. CA2528050 entitled Track structure for rail borne vehicles, particularly trains' as shown in figure 6 of the drawings accompanying this specification. The gist of the invention is given
below:
Abstract: Disclosed is a track structure for railborne vehicles, particularly trains, comprising a bed on which rails (1, 2) rest that are fixed to sleepers (3). Said track structure is characterized in that the bed consists of a concrete trough (4) that rests on a substructure (5) and is provided with sidewalls (4a, 4b) which extend in a longitudinal direction and are located parallel t o each other at a distance corresponding at least to the sleeper length L

The main disadvantage is that it is not possible to use such system in underground haulage tracks due to its heavy structure and difficulty in transportation.
Reference may be made to European patent no. EP1640498 entitled 'Sleeper assembly and railroad switch' as shown in figure 7 of the drawings accompanying this specification.
Abstract: The sleeper connector block (1) is made of concrete and has at least two sleeper parts (3) which are connected to one another in a piece and between them form a drive pocket (5) for the parts of the points-interlocking. The drive pocket when built in is bordered underneath by a base plate (4) connected to the sleeper part which forms a smooth laying surface facing the track bed.
The main disadvantage of this system is that it is costly, uses lot of concrete thus making it heavier and difficulty in transportation of these sleepers in underground mine or a tunnel.
Hence, it is clear from the hitherto known prior art that there is a definite need to provide a sleeper, which can easily and reliably ensure a proper reinforcing and supporting of the mine/tunnel haulage track system.
The main object of the present invention is to provide a novel pre-stressed rail sleeper particularly useful for underground haulage track, which obviates the drawbacks of the hitherto known prior art as detailed herein above.
Another object of the present invention is to provide a sleeper which not only supports a pair of rail tracks for smooth functioning of mine / tunnel haulage system but also strengthens other sleepers in the haulage track.
Yet another object of the present invention is to provide guarantee for holding the pair of rails at a uniform predetermined distance/spacing which is placed over a layer of ballast of a particular thickness.
Still another object of the present invention is to provide a sleeper which has nominal chemical reaction with the ballast materials which provides security for prolong utility of the sleeper.
Still yet another object of the present invention is to provide an eco-friendly sleeper which meets the scarcity of wooden sleepers due to uncontrolled deforestation.
A further object of the present invention is to provide a reusable sleeper in terms of prolong life expediency.
A still further object of the present invention is to provide a sleeper which provides better contact / bonding strength between the rails and the sleepers.
A yet further object of the present invention is to provide a sleeper which equips uniform inter-track distance/alignment of the rails which provides smooth motion of mine cars/tubs on the track.
Another object of the present invention is to provide a simple designed sleeper which is easily, cheaply and reliably manufactured as well as installed using the same prevailing techniques.
Still another object of the present invention is to provide a sleeper which can check the chances of stealing in comparison to wooden sleeper which is prevalently used as fire wood.
Yet another object of the present invention is to provide a sleeper which is easily maneuverable & transportable to and from the mine.
Still yet another object of the present invention is to provide a sleeper which requires less maintenance cost of track.
A further object of the present invention is to provide a sleeper which is useful for reinforcing mine track having simple design, light weight, easy to manufacture, cheap & easy installation procedure and easy to handle which obviates the drawbacks of the above noted hitherto known prior art.
The present invention consists of a pair of C-shaped flats of rectangular section which is welded with a pair of pre-stressed steel tie rods of circular section with suitable diameter which forms a D-shaped loop. A pair of D-shaped loop combination is connected to each other by two pairs of each rectangular steel flats by means of welding which has threaded hole within at the top ends. Both the bottom end of the D-shaped loop are welded with the plurality of individual U-shaped steel wires forming a web, whilst the middle portion is a rectangular shaped steel rod. A folded wire net of suitable size is inserted inside the webs made by U-shaped wires at the bottom portion of the D-shaped loop. Both the end of the assembly is concretized in a suitable rectangular shaped slab which contains the portion of C-shaped steel flat, tie rods, and full of steel flats, U-shaped net and web inside the slab. Two pairs of nuts and cleats each having a hole within is fixed upon both the concrete
slabs by means of threaded hole with the steel flats. This sleeper is easy to manufacture, install and maintenance which makes it cheaper and eco-friendly in nature due to prevent deforestation in comparison to other concrete sleeper.
In figures 8 to 11 of the drawings accompanying this specification an embodiment of the sleeper of the present invention for reinforcement of a haulage track in a mine is illustrated.
In the embodiment of this invention, as shown in figures 8 to 11 of the drawings, it reveals that it contains a pair of C-shaped flats (3) of rectangular section. A pair of steel tie rods (2) of circular section with suitable diameter is welded in pre-stressed condition to accommodate the steel flats (3) which forms a D-shaped loop (2,3). A pair of D-shaped loop combination (2 & 3) is connected to each other by two pairs of each rectangular steel flats (7) by means of welding. Each rectangular steel flats (7) has threaded hole within at the top ends. Both the bottom end of the D-shaped loop are welded with the plurality of individual U-shaped steel wires forming a web (8), while the middle portion is welded with a rectangular shaped steel rod frame (5). A folded wire net (9) of suitable size is inserted inside the steel wire webs (8) made by U-shaped wires at the bottom portion of (3). Both the end of the assembly (2, 3, 5, 7, 8 & 9) is concretized in a suitable rectangular shaped slab which encloses a portion of 2 & 3, and full of 7, 8 & 9 inside the slab. Two pairs of nuts (6) and cleats (4) each having a hole within is fixed upon both the concrete slabs (1) by means of threaded hole with the steel flats (7).
Accordingly the present invention provides a novel pre-stressed rail sleeper particularly useful for underground haulage track, which comprises: a pair of
D-shaped loop (2,3) consisting of a pair of C-shaped flats (3) being connected by means, such as welding, to a pair of steel rods (2), the said pair of D-shaped loop (2 & 3) being connected to each other at the top ends by means of two pairs of rectangular steel flats (7) having threaded hole within, at the bottom ends by means of a plurality of U-shaped steel wires (8), and in the middle by a rectangular shaped steel rod frame (5), in the inside of the webs (8) made by U-shaped wires at the bottom portions of (3) being inserted at both ends folded wire net (9); the ends of said assembly (2, 3, 5, 7, 8 & 9) being concretized to form slabs (1) at both ends which encloses the said steel flats (7), U-shaped steel wires (8) and folded wire nets (9) and the end portions of the said D-shaped loops (2,3); on the top of the said concrete slabs (1) being provided means for fixing rails, such as cleats (4) fixed by means of nuts (6) to the threaded hole of each of the said flats (7).
In an embodiment of the present invention, the C-shaped flats (3) are of rectangular section.
In another embodiment of the present invention, the steel rods (2) are of circular section.
In still another embodiment of the present invention, the pair of D-shaped loop (2,3) consisting of a pair of C-shaped flats (3) being connected by means, such as welding, to a pair of steel rods (2) kept in pre-stressed condition.
In yet another embodiment of the present invention, the pair of D-shaped loop (2 & 3) being connected to each other at the top ends by means of two pairs of rectangular steel flats (7) having threaded hole within, at the bottom ends by means of a plurality of U-shaped steel wires (8), and in the middle by
a rectangular shaped steel rod frame (5), all by the method of welding with the body of pair of D-shaped closed loops (2,3).
In still yet another embodiment of the present invention, the means for fixing rails, such as cleats (4) is replaced by spring clip system.
In a further embodiment of the present invention, the ends of said assembly (2, 3, 5, 7, 8 & 9) being concretized to form slabs (1), such as of rectangular, trapezoidal cross-section.
The main novelty of the present invention is to provide a pre-stressed rail sleeper particularly useful for underground haulage track which obviates the drawbacks of the hitherto known prior art as detailed above.
Another novelty of the present invention is to provide a sleeper which not only supports a pair of rail tracks for smooth functioning of mine / tunnel haulage system but also strengthens other sleepers in the haulage track.
Yet another novelty of the present invention is to provide guarantee for holding the pair of rails at a uniform predetermined distance/spacing which is placed over a layer of ballast of a particular thickness.
Still another novelty of the present invention is to provide a steeper which has nominal chemical reaction with the ballast materials which provides security for prolong utility of the sleeper.
Still yet novelty object of the present invention is to provide an eco-friendly sleeper which meets the scarcity of wooden sleepers due to uncontrolled deforestation.
A further novelty of the present invention is to provide a reusable sleeper in terms of prolong life expediency.
A still further novelty of the present invention is to provide a steeper which provides better contact / bonding strength between the rails and the sleepers.
A yet further novelty of the present invention is to provide a sleeper which equips uniform inter-track distance/alignment of the rails which provides smooth motion of mine cars/tubs on the track.
Another novelty of the present invention is to provide a simple designed sleeper which is easily, cheaply and reliably manufactured as well as installed using the same prevailing techniques.
Still another novelty of the present invention is to provide a sleeper which can check the chances of stealing in comparison to wooden sleeper which is prevalently used as fire wood.
Yet another novelty of the present invention is to provide a sleeper which is easily maneuverable & transportable to and from the mine. Still yet another novelty of the present invention is to provide a sleeper which requires less maintenance cost of track.
The non-obvious inventive steps of the novel pre-stressed rail sleeper particularly useful for underground haulage track, resides in the combination of the following:
(a) It contains a pair of steel tie rods of circular section with suitable
diameter welded under pre-stressed condition with a pair of C-shaped
flats of rectangular section to form a D-shaped loop which sustains
bending stress during dynamic loading.
(b) It has plurality of individual U-shaped steel wires (web) for holding the
concrete grout within the frame.
(c) In the middle of the frame, a rectangular shaped steel rod is welded to
provide stability in position and to provide hand hold facility for
carrying purpose.
(d) It has a folded wire net of suitable size which is inserted inside the
webs for reinforcing the concrete structure to make it strong and
stable.
(e) It has suitable rectangular shaped concrete slabs structure at both
ends for better absorption of shock loads on rails.
(f) Rectangular shaped small concrete slabs at the ends in stead of full
concretization of frame makes the sleeper lighter and economical.
The following example is given by way of illustration of the working of the invention in actual practice and therefore should not be construed to limit the scope of the present invention.
Example-1
A pre-stressed rail sleeper for supporting a haulage track in a mine was manufactured as detailed in the embodiment of the present invention in figures 8 to 11 of the drawings. A D-shaped loop (2,3) of 82 cm long was formed by welding a steel tie rod (2) of circular section having 10 mm thickness & length 52 cm in pre-stressed condition with a C-shaped flat (3) of rectangular section having 2cm width & 1cm thickness (pre-stressing is done by pressing the C-shaped flat inwardly through an external force suitably at the time of welding with the tie rod). A frame was fabricated by welding with a rectangular shaped 10mm steel rod (5) and a pair of rectangular steel flats (7) having size 75mmx15mmx12mm at each end. Distance between nearer rectangular steel flats (7) is 56mm while 76 mm for farther. Each rectangular steel flats (7) has threaded hole within at the top ends. Both the bottom end of the D-shaped loop are welded with the plurality of individual U-shaped steel wires (web) (8),. A folded suitable wire net (9) of suitable size is inserted inside the webs (8) made by U-shaped wires at the bottom portion of (3). Both the end of the assembly (2, 3, 5, 7, 8 & 9) is concretized in a suitable rectangular shaped slab which contains the portion of 2 & 3, and full of 7, 8 & 9 inside the slab. The dimension of concrete slab is 21mmx10.5mmx12mm. Two pairs of nuts (6) and cleats (4) each having a hole within is fixed upon both the concrete slabs (1) by means of threaded hole with the steel flats (7).
The manufactured rail sleeper was subjected to compression test of slab. It was found that the concrete could withstand the pressure of 450 kg/sq cm. It was also thrown several times from a height of 2m to check the effect of impact load. It was found to be alright even after 10 times of free fall.
The main advantages of the present invention for pre-stressed rail sleeper particularly useful for underground haulage track are:
1. It has nominal chemical reaction with the ballast materials which provides
security for prolong utility of the sleeper.
2. Scarcity of wooden sleepers due to uncontrolled deforestation, it meets
the requirements eco-friendly.
3. It can be reused due to prolong life expediency.
4. It can be easily, cheaply and reliably manufactured as well as installed
using the same prevailing techniques due to simple design.
5. It equips uniform inter-track distance/alignment of the rails which provides
smooth motion of mine cars/tubs on the track.
6. It provides better contact / bonding strength between the rails and the
sleepers.
7. It checks the chances of stealing in comparison to wooden sleeper which
is prevalently used as fire wood.

8. It is easy to transport inside/out side the mine.
9. It provides less maintenance cost of track.

We claim:
1. A novel pre-stressed rail sleeper particularly useful for underground
haulage track, which comprises: a pair of D-shaped loop (2,3) consisting of a
pair of C-shaped flats (3) being connected by means, such as welding, to a
pair of steel rods (2), the said pair of D-shaped loop (2 & 3) being connected
to each other at the top ends by means of two pairs of rectangular steel flats
(7) having threaded hole within, at the bottom ends by means of a plurality of
U-shaped steel wires (8), and in the middle by a rectangular shaped steel rod
frame (5), in the inside of the webs (8) made by U-shaped wires at the
bottom portions of (3) being inserted at both ends folded wire net (9); the
ends of said assembly (2, 3, 5, 7, 8 & 9) being concretized to form slabs (1)
at both ends which encloses the said steel flats (7), U-shaped steel wires (8)
and folded wire nets (9) and the end portions of the said D-shaped loops
(2,3); on the top of the said concrete slabs (1) being provided means for
fixing rails, such as cleats (4) fixed by means of nuts (6) to the threaded hole
of each of the said flats (7).
2. A novel pre-stressed rail sleeper as claimed in claim 1, wherein the C-
shaped flats (3) are of rectangular section.
3. A novel pre-stressed rail sleeper as claimed in claim 1-2, wherein the steel
rods (2) are of circular section.
4. A novel pre-stressed rail sleeper as claimed in claim 1-3, wherein the pair
of D-shaped loop (2,3) consisting of a pair of C-shaped flats (3) being
connected by means, such as welding, to a pair of steel rods (2) kept in pre-
stressed condition.
5. A novel pre-stressed rail sleeper as claimed in claim 1-4, wherein the pair
of D-shaped loop (2 & 3) being connected to each other at the top ends by
means of two pairs of rectangular steel flats (7) having threaded hole within,
at the bottom ends by means of a plurality of U-shaped steel wires (8), and in
the middle by a rectangular shaped steel rod frame (5), all by the method of
welding with the body of pair of D-shaped closed loops (2,3).
6. A novel pre-stressed rail sleeper as claimed in claim 1-5, wherein the
means for fixing rails, such as cleats (4) is replaced by spring clip system.
7. A novel pre-stressed rail sleeper as claimed in claim 1-6, wherein the ends
of said assembly (2, 3, 5, 7, 8 & 9) being concretized to form slabs (1), such
as of rectangular, trapezoidal cross-section.
8. A novel pre-stressed rail sleeper particularly useful for underground
haulage track, substantially as herein described with reference to the
example and figures 8 to 11 of the drawings accompanying this specification.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=F9/JHHAZpIUdjaV/ARgT5Q==&loc=+mN2fYxnTC4l0fUd8W4CAA==

« Previous Patent

Next Patent »

Patent Number

279834

Indian Patent Application Number

956/DEL/2007

PG Journal Number

05/2017

Publication Date

03-Feb-2017

Grant Date

31-Jan-2017

Date of Filing

03-May-2007

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

ANUSANDHAN BHAWAN, RAFI MARG, NEW DELHI-110 001,INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	MAITY SIBNATH	CENTRAL MINING RESEARCH INSTITUTE, BARWA ROAD,DHANBAD, JHARKHAND-826001
2	SINGH MANOJ KUMAR	CENTRAL MINING RESEARCH INSTITUTE, BARWA ROAD,DHANBAD, JHARKHAND-826001

PCT International Classification Number

E01B 9/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA