GB2062728A

GB2062728A - Cutting Tool

Info

Publication number: GB2062728A
Application number: GB8035939A
Authority: GB
Original assignee: Hall and Pickles Ltd
Current assignee: Hall and Pickles Ltd
Priority date: 1979-11-14
Filing date: 1980-11-07
Publication date: 1981-05-28

Abstract

A replaceable wear resistant tip 1 has an inner periphery 5 provided with at least one projection or recess 6 which extends laterally with respect to the plane 7 of cutting displacement of the tip in use, the projection or recess 6 being adapted to mate with a complementary recess or projection of a cutting tool or cutting tool holder on which the tip 1 is mounted in use, whereby the tip 1 is removable from the cutting tool or cutting tool holder only in a direction extending laterally with respect to the plane 7 of cutting displacement of the tip, in use. <IMAGE>

Description

SPECIFICATION Cutting Tool This invention relates to a replaceable, wear resistant tip for a cutting tool or cutting tool holder, such as is used for mining operations, e.g.

coal cutting and roadway driving; civil engineering applications, e.g. tunnel and trench excavating; or for the digger teeth of excavators.

In the mining industry for instance, a standard technique of removing coal from a face consists in the reciprocation of a bidirectional plough armed with cutting tools and intended to remove a web, e.g. of 4" depth, upon each traverse of the face.

With such ploughs it is necessary to provide cutting tools not only for removing the web, but also for trimming the floor to avoid difficulties during the progressive advance of the plough in accordance with the rate of coal removal from the face. Floor trimming is effected by clearance cutters having two cutting edges, one serving to cut the floor and the other serving to cut the immediately adjacent face of the seam. However, in relatively difficult floor conditions, clearance cutters have a very short service life even when tipped or faced with a wear resistant material, and consequently it is necessary to replace clearance cutters after the plough has effected a small number of cutting runs. It will be appreciated that the plough is out of use, with a consequent loss of production while the clearance cutters are replaced.This is an awkward operation in the limited confines and conditions of a coal face, while furthermore, such cutters are relatively expensive and are not insubstantial in size-thus placing additional burdens on a mine transport system by the requirement to transport fresh cutters to the face and to remove worn cutters from the face for refurbishing. Other applications result in plant being idle while similar replacement of worn components is effected.

According to the present invention, a replaceable wear resistant tip for a cutting tool or cutting tool holder has an inner periphery provided with at least one projection or recess which extends laterally with respect to the plane of cutting displacement of the tip in use, the projection or recess being adapted to mate with a complementary recess or projection of a cutting tool or cutting tool holder on which the tip is mounted, in use, whereby the tip is removable from the cutting tool or cutting tool holder only in a direction extending laterally with respect to the plane of cutting displacement of the tip, in use.

This arrangement ensures that the tip firstly is adequately supported by the cutting tool or cutting tool holder during cutting and secondly is retained by the cutting tool or cutting tool holder during reversal. It is necessary, of course, to provide a cutting tool or cutting tool holder with a complementary external profile, e.g. by machining, to accept the internal profile of the tip, but once this has been effected, worn tips in accordance with the present invention can readily be removed laterally and a fresh tip applied laterally to the tool or holder.With a clearance cutter for a mineral plough for instance, there is avoided the need to remove the tool or holder as a whole from the plough, resulting in shorter downtime, while tipsin accordance with the invention are smaller in size than clearance cutters of ploughs and hence are more easily handlable and transportable, while furthermore are relatively inexpensive.

The invention also includes a cutting tool or cutting tool holder provided with a replaceable wear resistant tip as defined above.

Preferably, the tip has a "V"-shaped external profile. In this case, the tip may comprise mutually divergent first and second elements, which may have a planar outer surface. It is also preferred for the inner surface of each element to be provided with a projection or recess. In detail, the or each inner surface may be provided with a projection at or towards the terminal end of each element, to engage behind a complementary recess of a cutting tool. Each inner surface may for instance be provided with an arcuate, rectangular, keyway, dovetail, etc., projection. It will be appreciated, however, that recesses or projections, or combinations of recess and projections, may be provided at any one or more suitable locations along the length of the inner surface.

In accordance with another preferred feature, one side of the tip is provided with a closure wall or bar which is particularly suitable for a clearance cutter of a coal plough.

In certain circumstances, the tip and tool may be subjected to side loading, in which case the tip may be positively retained on the tool or holder by fitting a dowel pin, bolt or rivet through a hole in the tip to engage a co-axial hole in the tool or holder.

Preferably, the tips are produced as castings, e.g. in manganese steel. Furthermore, the tips may be surfaced, e.g. by metal spraying, welded deposition etc., with materials offering greater resistance to wear, e.g. Stellite.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a tip in accordance with the present invention; Figure 2 is a side elevation of the tip of Figure 1 mounted on a cutting tool holder; Figure 3 is a view in the direction of arrow A of Figure 2; Figure 4 is a view in the direction of arrow B of Figure 3; Figure 5 is a section on the line V-V of Figure 4, and Figure 6 is a plan view of Figure 2 with, for clarity, the cutting tool holder removed.

In the drawings a replaceable wear resistance tip 1 has a "V"-shaped external profile comprising mutually divergent first and second elements 2, 3, each having a planar outer surface 4 and each having an inner periphery 5 provided with an inward projection 6, which projections extend laterally with respect to the plane of cutting displacement of the tip 1 in use, which plane is indicated generally by the arrow 7. At one side 8 the tip 1 is open, while at the other side 9, there is provided a closure wall 10. Both elements 2, 3, are provided with a co-axial hole 11, to receive e.g. a dowel pin (not shown) by which the tip 1 may if required be positively retained on a cutting tool holder 12 shown in Figure 2, the holder 12 being provided with corresponding recesses 13 to receive the lateral projections 6, and wedgeshaped supporting nose 14 to support the peripheries 5, and if required, having a hole 1 5 co-axial with the holes 11.

In use, to remove a worn or damaged tip 1 from a cutting tool holder 12, any dowel pin present is firstly removed from the holes 11 and 1 5, and the tip 1 is slid laterally with respect to the holder 12, with a fresh tip 1 replaced by the reverse of this action, correct location of the tip on the holder 12 being determined when the closure wall 10 abuts the nose 14.

Claims

1. A replaceable wear resistant tip for a cutting tool or cutting tool holder having an inner periphery provided with at least one projection or recess which extends laterally with respect to the plane of cutting displacement of the tip in use, the projection or recess being adapted to mate with a complementary recess or projection of a cutting tool or cutting tool holder on which the tip is mounted, in use, whereby the tip is removable from the cutting tool or cutting tool holder only in a direction extending laterally with respect to the plane of cutting displacement of the tip, in use.

2. A tip as claimed in Claim 1, having a "V"shaped external profile.

3. A tip as claimed in Claim 2, wherein the tip comprises mutually divergent first and second elements.

4. A tip as claimed in Claim 3, wherein the divergent elements each have a planar outer surface.

5. A tip as claimed in any one of Claims 2 to 4, wherein the inner surface of each element is provided with a projection or recess.

6. A tip as claimed in any one of Claims 2 to 5, wherein the or each inner surface is provided with a projection at or towards the terminal end of each element.

7. A tip as claimed in any preceding Claim provided with an arcuate projection(s).

8. A tip as claimed in any one of Claims 1 to 6, provided with a rectangular projection(s).

9. A tip as claimed in any one of Claims 1 to 6, provided with a keyway projection(s).

10. A tip as claimed in any one of Claims 1 to 6, provided with a dovetail projection(s).

11. A tip as claimed in any preceding Claim provided with a plural number of recesses and/or projections.

12. A tip as claimed in any preceding Claim provided with a closure wall at one side thereof.

13. A tip as claimed in any one of Claims 1 to 11, provided with a closure bar at one side thereof.

14. A tip as claimed in any preceding Claim, provided with a hole to receive a dowel pin, bolt or rivet.

15. A tip as claimed in any preceding Claim, produced by casting.

1 6. A tip as claimed in Claim 15, wherein the casting is effected in manganese steel.

17. A tip as claimed in any preceding Claim, surfaced with a highly wear resistant material.

1 8. A tip substantially as hereinbefore described with reference to the accompanying drawings.

19. A cutting tool or cutting tool holder provided with a replaceable wear resistant tip as defined in any preceding Claim.

20. A cutting tool or cutting tool holder as claimed in Claim 1 9 wherein the tip is positively retained in the tool or holder by fitting a dowel pin, bolt or rivet through a hole in the tip to engage a co-axial hole in the tool or holder.

21. A cutting tool or cutting tool holder substantially as hereinbefore described with reference to the accompanying drawings.