Title of Invention

A METAL TIP

Abstract

Tool (1) and metal tip (3) of the tool (1), said tool (1) including a tool blank (2), a bearing portion (4) and a metal tip (3) where the tool (1) is intended to be rotatably mounted in a road planing cutter, the longitudinal axis of said tool (1) forms, in active position, an angle V in the interval 20-900 relative to the road surface, said metal tip (3) including a portion (6) for attachment to the tool blank (2) and a cylindrical or slightly conical portion (7) is connected to a shape-defining surface (8) located at the opposite end of the metal tip (3) in relation to the attachment portion (6), said metal tip (3) being mounted in the tool and contacting the road surface in active position, where the metal tip (3) has a sharp edge (9) in the transition between the cylindrical or slightly conical portion (7) and the shape-defining surface (8).

Full Text

The present invention relates to t metal tip intended to be connected to a tool blank for creating a rotatable tool for mounting in a road planing cutter, said tool in operative position carrying out snow clearing and scraping of especially tough/hard ice and of other tough/hard road surface, the longitudinal axis of the tool forming an angle with the road surface in the interval of 20-90° and a metal tip or a hard metal tip of the tool contacting the road surface in active position of the tool. The invention also relates to the metal tip per se. The conventional road-grading steels have during the years been improved step by step due to the general technical development. The simpler plysical properties like hardness and toughness, and how they are affected by the chemical composition and heat treatment of the steels, have been fairly well known. Already decades ago the conventional steels have empirically reached their optimum length of life. This is clearly shown in the publication Test och utvardering av slitage-motstandet hos vagatal" (Teknikum, Uppsala universitet, dec 1983. ISSN 0346-8887). The knowledge of tribology, i.e. the teaching of friction, lubrication and wearing, was however rather rudimentary outside the academic world. The manufacturers of the conventional road planing cutters had virtually no knowledge of tribology. Studies of the research results of recent years have however shown that the wearing mechanics when working road surfaces are no isolated functions but cooperate with each other under the influence of a number of outer parameters. These studies have shown that the wearing of tool and pin is in micro scale. Fractures in and outside grain boundaries and wearing of tools takes place on .surfaces that can be smaller than a square millimetre. This is documented in the publication "Tribological testing of traditional road-grading steel leading to the evolution of new roadpreparation concepts", (Wear 130, 1989, S.151-165). Systematic and methodical follow-up from 1984 and onwards and the use of the so-called "SYSTEM 2000", a system solution for road planers in maintenance work that relies on SE-A-8404673-9, however, have now shown that cemented carbide tools in the market cannot solve all the frequent problems thdt arise in working road surfaces. This is partly due to the fact that the pins" as a result of the working leave a roadway with grooves that may be troublesome and that too much material passes between the pins. These inconveniences one has previously tried to eliminate by placing the pins closer to each other by drilling the mounting holes in the mounting plate closer to each other. This gave rise to mounting problems and problems with too low surface pressure to work the material underneath. :M-om SE-A-8404673-9 (the so called conventional pins) is previously known a road planing cutter as mentioned above. The tools used in connection with said road planing cutter have been of standard design, i.e. the same type of tools that are used for asphalt milling. coal breaking etc.. These tools are thus designed to carry out a cutting operation and therefore a common feature of them is that the cemented carbide insert has a relatively pointed design to minimize the cutting forces. In early use of these conventional pins, standard pins, it was found that relatively extensive damage of the road surfacing occured already at a few degrees increase of the angle between the longitudinal axis of the pin and the horizontal plane. It was also found that also the relatively small increase of the angle caused a rolling working to transfer into a cutting non-rolling working, this being negative due to the fact that the material in e.g. a gravel roadway was cut down and thereby the stone material, giving the roadway its bearing capacity, was cut down and segregated into smaller fractions with lower bearing capacity. Also the wear upon the tool itself was more than ten times greater than when the angle was absolutely correct. The relatively minor increase in the angle also causes a relatively low specific contact pressure between tool and road surface to rapidly transfer into an extremly high surface pressure with extensive damage to the road surfacing as a consequence. The pointed standard pins (SE-A-8404673-9) have thus a very small scope of latitude before damages occur both in the road surfacing and in the tool itself. A further development of "SYSTEM 2000" through SE-B-8701222-5.(the so-called blunt pin) , shows that a tool with a smoothly curved shape defining surface has a large scope of latitude whereby the angle that the longitudinal axis of the tool forms with the horizontal plane can be varied within relatively wide limits without affecting the function of the tool to any degree worth mentioning. The friction/pressure and degree of working of the tool are fairly equal within 2 0-90° inclination between the longitudinal axis of the tool and the horizontal plane. Also the working continually takes place as a rolling crushing working v?hereby very long life for the tool is achieved. The smoothly curved shape defining surfaces of the tool also continually cause a significant reduction of the maximum specific surface pressure against the ground, whereby damages in the road surfacing can be avoided to a high extent. In these studies one has been able to distinguish between the totally different ways of working and working results of the conventional pins" way to work material and the dull pins" way to work material. It has therefore been possible to systematically and methodically determine the system structure and type of motion and type of wear of the pins in the marketplace. It has therefore been possible to consider advantages and drawbacks of the different types of pins and their stability and limitation as regards function. A disadvantage and weakness of the above mentioned pin with the rounded shape defining surfaces, that cause the structural limitation of the maximum surface pressure, is that the pin due to its design is not able to penetrate hard/tough ice or hard/tough other-material that cannot be worked by crushing. The above described pins and other known cemented carbide pins have bodies with a concave or conical portion that closest to their mounting part have an essentially larger diameter than the rest of the tool body. This design with a thicker base diameter and an essentially thinner tip diameter has been functionally determined by the original areas of use for the conventional cemented carbide tools, i.e. milling, cutting working. This geometrical shape of the very holder body for the cemented carbide tip does riot bring about an optimum function of the tool nor does it solve all the technical problems inherent in ground preparation. The previously known pins that were designed with a concave portion could also contribute to a premature breakdown through fracture of the conical portion due to the smaller diameter of the initially weaker thinner portion. Two essentially different ways to work material from solid bodies have been described above. The first way is a solid body performing a sliding, cutting abrasive wearing. The other way is a rolling body performing a crushing working. THE AIM OF THE INVENTION: The aim of the invention is to present a tool including a metal tip or cemented carbide tip with a special design, said tool being especially adapted to hard/tough ice and other hard/tough road surfacing. The aim is also to solve the problems mentioned above related to existing pins by changing the geometrical design. The larger diameter of the new pin also improves the rotation of the pin and thereby its length of life. By designing the pin with constant cylindrical diameter on the portion that holds the metal tip itself several technical problems are solved. With its new tip design the tool can now manage to perform working that previously was not possible with conventional pins. This is due to the fact that working now takes place by rolling, cutting working with an optimum length of life. The large diameter of the new pin prevents unduly much material to pass between the pins. The absence of a concave waist means considerably more material in the tool body whereby a longer length of life and strength is achieved. The tools that are to be used both in hard/tough ice and hard/tough other material in the roadway must cover a larger working register than the tools described above. The present invention has the aim to present a tool that essentially performs rolling, cutting working due to the metal tip being so designed that the angle between the longitudinal axis of the tool and the horizontal plane can be varied within wide limits to have the surface pressure successively increasing from minimum surface pressure at 90° to maximum surface pressure at about 4 0°. Due to the fact that the contact point of the metal tip is at large distance from the centre of rotation, said rotation is favoured giving optimum length of life to the pin. A further aim of the present invention is to achieve a tool including a cemented carbide tip for a wider working field than has previously been possible with conventional tools. According to the present invention the material is being worked by cutting, rolling working, i.e. the present invention combines the planing cutting effect of the standard pins with rolling working of the above-mentioned pin with rounded shape defining surfaces. Thus the present invention brings about a third way to work material from solid bodies, i.e. a rolling body performs a cutting working, said third way being essentially different from the two ways mentioned above. Under certain conditions the ways of working are not present as isolated functions but are interworking under the influence of a great number of parameters. However, there usually always is a totally dominating working type, e.g. sliding, cutting; rolling, crushing or rolling, cutting. SUMMARY OF THE INVENTIdN: The invention is characterized in that the tool blank, to which the metal tip is brazed, is cylindrical, i.e. with a constant diameter from the mounting end towards the road planing cutter to the attachment end against the metal tip. Further the diameter of the cylindrical portion is in one embodiment considerably larger at the top of the tool than in previously used types of pins. The invention is further characterized in that the metal tip includes a cylindrical or slightly conical portion and especially an end portion with a sharp shape defining edge, said end portion being attached to the cylindrical or slightly conical portion. A sharp shape defining edge is an edge that is Bufficiently keen or sharp to provide a cutting working in any given material when performing road planing work. Thus the definition of "sharp edge" can vary with regard to the material that is subject to working. When the cutting working, by wearing of the metal insert, ceases and the working is turned into crushing working the cutting insert is worn out. A comparison can be made with a turning tool that is worn out when it no longer has the ability to cut the material. Due to the sharp edges of the metal tip a brittle fracture can more easily be created in the material that is worked resulting in a better economy. (Created brittle fractures propagate locally without further energy supplied). Through the publication "Model studies on cutting, grinding and abrasive wear of materials" (Teknikum, Uppsala universitet, ISBN 91-554-2 22-5) the great importance of the cutting angle for the working result has also been shown. The patent-pending pins use inter alia the fact that the so called BUE built-up edge prolongs the life of the metal pins due to the fact that material building up this BUE decreases the wear upon the metal tip itself. A metal tip with a tube-shaped end surface and a metal pin with an internal cone increases the specific surface pressure within a wide change of the angle relative to the ground surface and also essentially increases the possibility of the tool to easily penetrate hard and/or tough material and thereby facilitate optimum working through rolling, cutting working. These pins with sharp cylindrical or slightly conical shape defining surfaces can theoretically be described as consisting of m endless number of small tips that together constitute the circumference of (he end surface of the cylindrical or slightly conical envelope surface of the metal tip. In practice it has also turned out that the working at every single point of time and location along the tool surface and the road section takes place on an extraordinarily restricted area. Therefore it has been possible to optimate the present patent-pending pin for rotatably cutting tools. Accordingly, the present invention provides a metal tip intraded to be connected to a tool blank for creating a rotatable tool for mounting in a road planing cutter, said tip being formed of metal and having a rear attachment portion for attachment to the tool blank, said tip having one of a cylindrical and slightly conical portion extending between said rear attachment portion and said front end surface of said metal tip, the metal tip having a sharp circular cutting edge in the transition between said front end surfice and said one of the cylindrical and slightly conical portion. BRIEF DESCRIPTION OFTHEDRAWINaS. The invention will now be described more in detail by way of embodiments where references to the drawing figures are effected by using numeral references. Fig. 1 shows a tool equipped with a metal tip according to the invention with the metal tip at some distance from the tool blank; Fig. 2 shows a first embodiment of the metal tip where 2 a shows a perspective view from undemeath and 2b shows a section taken axially; Fig. 3 shows a second embodiment of the metal tip where 3a shows a perspective view from underneath and 3b shows a section taken axially; Fig. 4 shows a third embodiment of the metal tip where 4a shows a perspective view from underneath and 4b shows a section taken axially; and Fig. S shows a fourth embodiment of the metal tip where 3 a shows a perspective view from undemeath and 3b shows a section taken axially. DESCRIPTION OF THE INVENTION: The tool 1 is intended to be mounted on a road planing cutter (not shown)/ said tool 1 including a tool blank 2 with a metal tip 3 connected to the lower portion of the tool blank 2 and a bearing portion 4 connected to the upper portion of the tool blank 2. The tool blank is cylindrically designed whereby a constant tool diameter VD is present from the upper end of the tool blank 2, i.e. the mounting end towards the road planing cutter, to the attachment end for the metal tip. The bearing portion 4, that includes a surrounding clip (not shown) for the mounting, is intended to be rotatably secured in the road planing cutter. The bearing portion 4 is of quite conventional type for these types of rotating tools. The lower portion of the tool blank is provided with a conventional attachment portion 5 for the metal tip 3. The joint between the tool blank 2 and the metal tip 3 is a brazing joint. Fig.l, however, shows the tool 1 where the tool blank 2 and the metal tip 3 have been separated for the sake of clearness and terminology. This cylindrical tool can be mounted on conventional road planing cutters with a standardized centre distance between the tools, the so- called pins, whereby the diameter of the tools have been increased to have the distance A or, in other words, the play between the tools to be 1-21 mm along the free longitudinal axis of the tool. Thus the diameter VD of the tools is increased if conventional road planing cutters are used. The centre distance CA between two adjacent tools is CA = VD/2 + A + VD/2 = VD + A. In case the road planing cutters are to be newly manufactured the centre distance CA is adapted to a chosen optimum diameter VD of the tools where the tool diameter VD depends on the working conditions. Towards the tool blank 2 the metal tip 3 is provided with a contact portion 6 as attachment portion to be brazed against the attachment portion 5 of the tool blank 2. The contact portion 6 is of conventional design. Further the metal tip 3 is provided with a cylindrical or slightly conical portion 7 and a shape defining surface 8. Between the cylindrical or slightly conical portion 7 and the shape-defining surface 8 a sharp edge 9 is provided, i.e. the circular "corner" of the metal tip consists of a sharp edge 9. The metal tip 3 that is brazed to the tool 1 has a diameter HD that corresponds to the tool diameter VD, at least at one location along the length of the metal tip. In case the metal tip is slightly conical its diameter HD naturally varies along its length. Depending on the conicity is VD D, resp., where D is the diameter of the metal tip at the transition to the shape-defining surface. Also a double conical metal tip is possible whereby the conicity can increase or decrease towards the longitudinal centre of the tip and then decrease or increase up to the shape-defining surface. The metal tip shows in all consecutive embodiments a sharp edge between its envelope surface and its shape defining surface. This sharp edge is, as previously mentioned, defined by working mode and the ground. As shown in Fig.2 the metal tip according to the present invention has a planar shape-defining surface 81. The angle between the shape defining surface and the envelope surface of the metal tip is about 90". This angle can in this embodiment vary between 80 and 110°. In a second embodiment, Fig.3, the shape-defining surface of the metal tip is in the shape of a concave, circular shape-defining surface 82 that can have the shape of a spherical cap having a radius of curvature of 8-19 mm. In a third embodiment according to Fig.4 the shape-defining surface of the metal tip is shown as a planar circular end surface 83 with a central cylindrical recess 84 where the diameter of the recess is between D/2 and D/3 where D is the diameter of the metal tip at the transition to the shape-defining surface. In a fourth embodiment according to Fig.5 the shape-defining surface is designed as a planar, circular end surface 85 with a centrally located conical recess 86 with a largest diameter of between D/2 and D/3 where D is the diameter of metal tip at the transition to the shape-defining surface. The depth of the recess, i.e. the height of the cone is 3-8 mm. Thus the metal tip 3 according to the invention has a planar, circular end surface, concave end surface, annular surface with cylindrical recess or annular surface with internal cone in the centre. In all embodiments the metal tip 3 has a sharp edge 9 in the transition between the cylindrical or slightly conical portion and the shape-defining surface whereby the worked is For most applications the metal tip 3 is of cemented carbide but can also cover certain requirements when manufactured in high speed steel or free cutting steel. 1. A metal tip intended to be connected to t tool blank for creating a rotatable tool for mounting in a road planing cutter, said tip being formed of metal and having a rear attachment portion for attachment to the tool blank, said tip having one of a cylindrical and slightly conical portion extending between said rear attachment portion and said front end surface of said metal tip, the metal tip having a sharp circular cutting edge in the transition between said front end surface and said one of the cylindrical and slightly conical portion. 2. The metal tip according to claim 1, wherein the end surface has the shape of a planar circular surface. 3. The metal tip according to claim 1, wherein the end surface has the shape of a concave, circular surface. 4. The metal lip according to claim 3, wherein the concave end surface of the metal tip has the shape of a spherical cap with a radius of curvature of S-19 mm. 3. The metal tip according to claim 1, wherein the end surface has the shape of a planar circular end surface with a centrally located, cylindrical recess. 6. The metal tip according to claim 3, wherein the cylindrical recess in the end surface has a diameter between D/2 and D/3, where D is the outer diameter of die planar circular end surface. 7. The metal tip acoording to claim 1, wherein the end surface has the shape of a planar, circular end surface with a contrally located, conical recess. 8. The metal tip according to claim 7, wherein the conical recess has a largest diameter of between D/2 and D/3, where D is the diameter of the metal tip at the outer diameter of the planar circular end surface. 9. The metal tip according to claim 7, wherein the conical recess has a depth of 3-S mm. 10. The metal tip according to claim 1, wherein the metal tip is of cemented carbide. 11. A metal tip substantially as herein described with reference to the accompanying drawings.

Documents:

1676-mas-1996 others.pdf

1676-mas-1996 abstract.pdf

1676-mas-1996 claims duplicate.pdf

1676-mas-1996 claims.pdf

1676-mas-1996 correspondencne others.pdf

1676-mas-1996 correspondencne po.pdf

1676-mas-1996 description (complete) duplicate.pdf

1676-mas-1996 description (complete).pdf

1676-mas-1996 drawings duplicate.pdf

1676-mas-1996 drawings.pdf

1676-mas-1996 form-1.pdf

1676-mas-1996 form-26.pdf

1676-mas-1996 form-4.pdf

1676-mas-1996 form-6.pdf

1676-mas-1996 petition.pdf

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