Title of Invention

A DEVICE FOR MEASURING CONVERGENCE OF THE ROOF IN A MINE QUICKLY AND ACCURATELY

Abstract

A device for measuring convergence of the roof in a mine, quickly and accurately. A device for measuring convergence of the roof in a mine, quickly and accurately, which comprises in combination a plurality of vertically placed coaxial tubes (2,4,5) movably fixed by means (3,6), characterised in that a top tube (2) being provided with a sucker (1) attached at the top-end, the bottom-end of the said top tube (2) being co-axially connected by means (3) to the top-end of a middle tube (4) having measuring scale marked on its surface, the bottom-end of the said middle tube (4) being co-axially inserted into the top-end of a bottom tube (5) and held in position by means (6). (Fig-2)

Full Text

This invention relates to a device for measuring convergence of the roof in a mine, quickly and accurately. This invention particularly relates to a device for measuring convergence of the roof in a mine, which is economical, easy to assemble and dismantle, maintains verticality, provides accurate measuring and easy reading and is capable of indicating the convergence quickly and accurately. In underground mines, such as in coal mines, during coal extraction process it is necessary to have a formation of underground tunnels for pathways such as roadways, railways. In such a set-up there is every possibility and tendency of the mine roof to converge. The magnitude of convergence may be detrimental for mining operation in general and safety in particular. This is particularly so in bord & pillar mining. The rate of convergence of strata is an important parameter in predicting roof failure and subsequent accident occurring in mines. Also, this convergence rate is helpful in deciding the type of support system to be installed. An existing telescopic type convergence indicator is depicted in figure 1 of the drawings accompanying this specification. In case of such existing telescopic type convergence indicator, to measure convergence rate at a particular point, one has to decide and make arrangement for two-reference points, one on the roof and another on the floor, in between which reading is to be taken. For this purpose two rods having central punch mark are grouted into roof and floor exactly vertical / perpendicular to each other. That means for every measuring point one has to drill in the roof and the floor. At the same time verticality / perpendicularity between the reference points after having drilled has to be maintained, without which errorless reading is not possible. Reference may also be made to US patent no. 4,514,905, titled: Convergence extensometer for measuring mine roof subsidence, wherein is disclosed an extensometer for measuring changes in the vertical distance between the roof and floor of a mine opening which comprises; a pair of rigid telescoping members, a tension spring securing said members to each other in a telescoping relationship, a hook for attaching a non-extensible cable to each of said members, and an indicator for determining telescopic movement of said members. The extensometer of this invention is utilized by securing one of said telescoping members to the roof of the mine and the other telescoping member to the floor of the mine with the axis of said members being disposed along the vertical. The telescoping members are secured, under tension, to the mine roof and floor by means of a non-extendible cable such as a steel cable. The indicator for determining the telescopic movement of the members may be a pair of lugs or flanges or other indicating marks, each member of which pair is affixed to a separate telescoping member. There are varies type of instruments available, in the hitherto known prior art, such as telescopic type convergence indicator, remote convergence indicator to measure the daily convergence of a given strata in an underground mine. Although remote convergence indicators are used widely, these are costly and generally left in goaf to collect cumulative data for longer period of time. For their installation, one has to create notches in the pillar, which is a cumbersome task. At the same time if the wire connected with it are faulty or damaged by any means, it is impossible to take reading out of it. Some other US patents are available for devices to measure the height of various items, not particularly the height between the floor and the roof of a mine. These are either optical or electronics based and are very costly and not easy in handling and to operate particularly in Indian mining conditions. From the hitherto known prior art it is seen that there is a definite need to provide a device for measuring convergence of the roof in a mine, which is economical, easy to assemble and dismantle, maintains verticality, provides accurate measuring and easy reading process and is capable of indicating the convergence fast and accurately. The main object of the present invention is to provide a device for measuring convergence of the roof in a mine, quickly and accurately and obviate the drawbacks of the hitherto known prior art. Another object of the present invention is to provide a device for measuring convergence of the roof in a mine, which is economical. Yet another object of the present invention is to provide a device for measuring convergence of the roof in a mine, which is easy to assemble and dismantle. Still another object of the present invention is to provide a device for measuring convergence of the roof in a mine, which maintains verticality. A further object of the present invention is to provide a device for measuring convergence of the roof in a mine, which provides easy reading process and is capable of indicating the convergence fast and accurately. In the present invention there is provided a device which is useful for measuring height between the floor and the roof of mines. It consists of a top tube having a sucker at the top-end. The bottom-end of the top tube is connected by means of a lock nut to a middle tube having scale marked on its surface. This middle tube is inserted into a bottom tube and is held at any position by a clamp. A magnifying glass and a torch holder is provided for ease of reading the scale markings. A bob is provided to check the verticality of the device. The device of the present invention is economical, easy to assemble and dismantle, maintains verticality, provides accurate measuring and easy reading process and is a faster convergence indicating device, which is particularly useful for measuring convergence of the roof in a mine quickly and accurately. The device of the present invention is shown in figure 2 of the drawings accompanying this specification, wherein a top tube (2) has a sucker (1) attached at the top-end of the tube (2). The bottom-end of the top tube (2) is co-axially connected by means of a lock-nut (3) to the top-end of a middle tube (4) having measuring scale marked on its surface. The bottom-end of this middle tube (4) is co-axially inserted into the top-end of a bottom tube (5) and is held at the desired position by a clamp (6). A bob (7) is provided, fixed at the top-end of the top tube (2), to check the verticality of the device. A torch holder (8) is provided, fixed to the surface of the bottom tube (5) and a magnifying glass (9) is fixed at the top edge of the bottom tube (5) for ease of reading the scale markings. Accordingly the present invention provides a device for measuring convergence of the roof in a mine, quickly and accurately, which comprises in combination a plurality of vertically placed coaxial tubes (2,4,5) movably fixed by means (3,6), characterized in that a top tube (2) being provided with a sucker (1) attached at the top-end, the bottom-end of the said top tube (2) being co-axially connected by means (3) to the top-end of a middle tube (4) having measuring scale marked on its surface, the bottom-end of the said middle tube (4) being co-axially inserted into the top-end of a bottom tube (5) and held in position by means (6). In an embodiment of the present invention, to enable extended vertical reach more than one top tube (2) is co-axially connected by means (3) between the bottom-end of the top tube (2) provided with sucker (1) at the top-end and the top-end of the middle tube (4) having measuring scale marked on its surface. In another embodiment of the present invention, the top tube(s) (2) and the middle tube (4) are of the same diameter. In another embodiment of the present invention, the middle tube (4) is of diameter less than the diameter of the bottom tube (5) to enable telescopic co- axial insertion of the bottom-end of the said middle tube (4) into the top-end of the said bottom tube (5). In another embodiment of the present invention, the bottom-end of the said top tube (2) being co-axially connected by means such as a lock-nut (3) to the top-end of a middle tube (4) having measuring scale marked on its surface. In yet another embodiment of the present invention, the bottom-end of the said middle tube (4) being co-axially inserted into the top-end of a bottom tube (5) and held in position by means such as a clamp (6). In still another embodiment of the present invention, verticality check of the device is provided by means such as a bob (7) fixed at the top-end below the sucker of the top tube (2). In still yet another embodiment of the present invention, ease of reading of measuring scale is enabled by providing a magnifying glass (9) at the top edge of the bottom tube (5). In a further embodiment of the present invention, ease of reading of scale is enabled by providing a torch holder (8) fixed to the surface of the bottom tube (5). The novelty of the device of the present invention resides in enabling measuring convergence of the roof in a mine, which is economical, easy to assemble and dismantle, maintains verticality, provides accurate measuring and easy reading and is capable of indicating the convergence quickly and accurately. The novelty of the present invention has been realized by the non-obvious inventive steps of providing in combination a plurality of vertically placed coaxial tubes which are movably fixed by means of lock-nut(s) and a clamp, such as herein described. Further, the top tube is provided with a sucker attached at the top-end for easy fixation on mine roof. To enable extended vertical reach more than one top tube is co-axially connected by means of lock-nut(s) between the bottom-end of the top tube provided with sucker at the top-end and the top-end of the middle tube having measuring scale marked on its surface. The bottom-end of the middle tube having measuring scale marked on its surface is co-axially inserted into the top-end of the bottom tube and held in position by means of a clamp. For ease of reading of measuring scale is provided a magnifying glass and a torch holder. The operation of the device of the present invention for measuring convergence of the roof in a mine, quickly and accurately, is detailed below. To measure the height between the roof and floor in a mine, a point is located in the roof at the particular place where measurement is required. Then the bottom-end of the top tube (2) is connected with the help of lock nut (3) to the top-end of the middle tube (4) having measuring scale marked on its surface. The bottom-end of the middle tube (4) is already co-axially inserted into the top-end of the bottom tube (5). Then the device is erected vertically in such a manner that the sucker (1) at the top-end of the top tube (2) touches the roof at the predetermined point and the middle tube (4) already co-axially inserted into the top-end of the bottom tube (5) is held in position by clamp (6). The purpose of the special head with sucker (1) is to stick at the specified point in the uneven roof. The bob (7) which is hanging from the top portion of the top tube (2) helps in asserting the verticality of the device. After erection of the device vertically, the convergence is measured using the graduated measuring scale marked on the surface of the middle tube (4). The reading can be taken very easily using the magnifying glass (9), and a torch in torch holder (8) so provided for this purpose. After measurement is over one can dismantle it easily by loosening the means (3,6), that is clamp (3) and lock-nut (6) and detaching the middle and bottom tubes from the top tube. The main advantages of the device of the present invention for measuring convergence of the roof in a mine are: 1. Simple and economical to manufacture. 2. Assembly is very easy. 3. Dismantling is very easy. 4. No need for inserting reference point in the roof and the floor, which is a cumbersome process. 5. The sucker on the top tube head allows fixing on uneven mine roof, thus eliminating the requirement of search for any separate reference point, in the roof. 6. Verticality between the measuring points is easily maintained. 7. Provides easy readability of scale markings, thus allowing reading to be taken easily and accurately. 8. The device provides convergence indication with accuracy and speed. 7. A device as claimed in claim 1-6, wherein ease of reading of measuring scale is enabled by providing a magnifying glass (9) at the top edge of the bottom tube (5). 8. A device as claimed in claim 1-7, wherein ease of reading of scale is enabled by providing a torch holder (8) fixed to the surface of the bottom tube (5).

Documents:

2140-del-2004-Abstract-(27-04-2011).pdf

2140-del-2004-abstract.pdf

2140-DEL-2004-Claims-(19-10-2011).pdf

2140-del-2004-Claims-(27-04-2011).pdf

2140-del-2004-claims.pdf

2140-DEL-2004-Correspondence Others-(19-10-2011).pdf

2140-del-2004-correspondence-others (27-04-2011).pdf

2140-del-2004-correspondence-others.pdf

2140-del-2004-description (complete).pdf

2140-del-2004-drawings.pdf

2140-del-2004-form-1 (27-04-2011).pdf

2140-del-2004-form-1.pdf

2140-del-2004-form-18.pdf

2140-del-2004-form-2.pdf

2140-del-2004-Form-3-(27-04-2011).pdf

2140-del-2004-form-3.pdf

2140-del-2004-form-5.pdf