GB2043198A - A locking member for replaceable parts subject to wear in earth-moving machines - Google Patents

Abstract

A member for locking a removable component to a fixed component such as a digger tooth to an adapter. The member comprises two elongate plates 15, 16 spaced apart by a resilient element 17 such as a block of hard rubber, one of the plates 16 being thicker than the other and having a portion 20, 21 of reduced thickness formed in such a way as to provide two areas of weakness so that hitting one end of the one plate causes that portion 20, 21 of reduced thickness to buckle between the two weakened areas, the buckled portion being received in a recess 13 in the fixed component and the other plate 15 being forced up by the resilient material 17 into an opening in the removable component opposite the recess 13 in the fixed component thereby locking one component to the other. <IMAGE>

Description

SPECIFICATION A locking member for replaceable parts subject to 'wear in earth-moving machines The present invention relates to a locking member for replaceable parts in earth-moving machines.

Such parts which are subject to wear, include tooth and cutting edges for excavator and loader buckets, scarifier teeth and teeth for dredge cutters.

A great number of different types of locking members have been proposed and tried during the course of the years, but many of the types have been abandoned as they have not proved to be entirely reliable, have had poor resistance to wear and other stresses, or it has been difficult to install or remove them.

One of the more satisfactory types comprises a locking wedge having two elongate parts made of metal which are held together by a resilient middle part of comparatively hard rubber. Locking wedges of this type are pressed into a through opening between a main fixed component and a removable component which is required to be locked to the main component. The elongate parts of the wedge contact both the removable component and the main component to which the removable compo nent is to be locked. The through opening is made that much smaller than the depth of the locking wedge so that its rubber middle part is compressed.

This makes the wedge fit without play. As the elongate parts of the wedge are, as a rule, provided with locking edges of various shapes which engage other locking edges on the components which are to be locked relative to each other, the risk that the wedge will work out of the opening is practically eliminated. The locking wedge can moreover easily be removed by knocking it out with the aid of a drift and a sledge hammer.

A locking wedge of this type is described in Swedish Patent No. 333,551.

However, locking wedges of this type cannot readily be used when it is desired to insert the locking member in the same direction as that in which a removable component is inserted into a fixed component, for example a tooth in an adapter secured to a tool of an earth moving machine.

The present invention therefore relates to a lock ing member which can be inserted in the same direction as the removable part or component which it is to lock to the main component. A characteristic feature of the locking member according to the invention is that although it has two elongate parts and holding them together, a middle part made of resilient material, it is not primarily the resilient middle part which presses the elongate parts against the opening formed between the components to lock them together but a reduced thickness portion of one of the elongate parts being deliberately buckled to lock the member in the opening and thereby lock the components together.This portion is made in such a way that when the one elongate part is in contact with one of the components and one end of that part is struck by one or a plurality of heavy blows in the longitudinal direction of that part, the portion will buckle so that a middle portion of the one elongate part will move away from the other elongate part, If, in the'opening formed between the components, one of the components has a groove into which the buckled out portion can be received, an extremely good locking function is obtained.

In the accompanying drawings: Figure 1 is a fragmentary view of a cutter tooth in an adapter, the adapter being partly sectioned to show how the tooth is locked in the adapter by a locking member in accordance with this invention; Figure 2 is an isometric view of the locking member; Figure 3 is a sectional view of part of Figure 1 with the locking member inserted but not in its locking position; and Figure 4 and 5 each show the same sectional view as Figure 3 with a modified form of tooth which receives an alternative form of locking member. In Figure 4 the alternative form of locking member is shown inserted in its position between the tooth and an adapter, but not in its locking position whilst Figure 5 shows the member in its locking position.

In Figure 1, a cutter tooth 1 is shown inserted in positi6n in an adapter 2, only part of which is shown in the drawing. The tooth 1 is inserted (and removed) in the direction indicated by the arrow A in a groove in the adapter. On both sides of the groove the adapter has a land 3 which fits into a corresponding groove in the tooth, while the tooth on both sides has a land 4 which fits into a groove in the adapter.

The lands and the grooves and the rear edge 5 of the tooth and the abutment edge 6 of the adapter determine the fixed position of the tooth in the adapter.

On the underside of the tooth, facing the lower limb of the adapter, is an opening 7 into which a locking member can be inserted. In the embodiment shown in Figures 1 to 3, this opening is formed by portions 8 and 10 depending from the underside of the tooth, the inner portion 8 has an abutment edge 9 facing the nose portion of the locking member and the outer portion 10 has an inner edge which is, to a certain extent, obliquely chamfered at 11.

In the lower limb of the adapter 2 there is a recess 12 which is opposite the opening 7 when the tooth is in the holder. The recess 12 has an outer wall 13 and a through hole 14 which runs across the lower limb of the adapter and beneath the opening 7. The upper edge of the hole 14 is at least as high up on the adapter as to be on a level with the upper edge of the outer wall 13.

The locking member itself comprises two elongate parts 15, 16, made of metal, which are held together by a resilient middle part 17. The middle part is joined to the two elongate parts by gluing, or in some other known way. The middle part can be made of rubber or some other elastic material. Both of the elongate parts are of rectangular cross section. Part 15, which can be somewhat thinner than the other part 16, preferably has return bent ends 18, 19. The other, thicker part 16 has a portion of a reduced thickness formed by a ramp 20 terminating in flank 23 transverse to the upper surface of the part 16 and a similar ramp 21 terminating in a flank 24 in the lower surface of the part 16. The flanks 23 and 24 iay immediately above and below the start of the ramps 21 and 20 respectively.This particular formation provides weakened areas in the part 16 around the flanks 23 and 24 so that this portion of reduced thickness so formed allows part 16 to be buckled if the distal end is struck by a blow in the direction indicated by arrow B in Figure 3. By making the distance between the forward edge 22 and the flank 23 less than the distance between the abutment edge 9 and the wall 13, striking the end of part 16 when in the position shown in Figure 3 will force that part forwards so that the edge 22 hits the abutment 9 causing the reduced thickness portion to buckle downwards about flanks 23 and 21. The portion of reduced thickness carries with it that portion of the part 16 to which the resilient middle part 17 is secured.The ramp 21 will then be forced against the outer wall 13 of the recess 12 whilst the return bent portions 18 and 19 will engage the ends of the recess formed in the tooth between depending portions 8 and 10, the part 15 thus being forced up into the recess, all as shown in Figure 1.

The resiliency of the middle part 17 holds the locking member securely in the opening 7 and prevents any play between the tooth and the adapter and prevents the former from being withdrawn from the latter. Preferably, the middle part 17 is wedge shaped as shown in Figure 2. As shown in Figures 1 and 5, with a carefully adapted form of the recess 12, combined with appropriate dimensions for the locking member, the shallow part of the recess will act as a further supportforthe buckled out part 16. By knocking a drift through the opening 14, part 16, can be straightened out to allow the tooth and the locking member to be removed from the adapter.

As will be noted from the figures, in the normal case, and when not subjected to any load, the front edge 18 of the part 15 extends somewhat farther forward in front of the front edge 22 and is bent down towards part 16. When the part 16 is struck it will thus first be forced forwards owing to the prestressing of the resilient middle part until its front edge 22 comes into contact with the abutment edge 9 and buckling will take place only thereafter. As the resilient middle part 17 strives to resume its original form, the front edge 18 of part 15 will be forced against the edge 9 of the tooth at the same time as the buckled out section of part 16 is forced against the wall 13 of the adapter 2.It is thus only at more extreme loads that the edge 9 will be displaced into direct contact with the front edge 22 of part 16, but the movement of the tooth in this direction will then be totally arrested as the buckled out portion of part 16 provides a metallic connection between the depending portion 8 on the tooth and the wall 13 in the adapter.

The resilient middle part 17 of the locking member shown in Figures 1 to 3 is of a shape and size that the rear portion of part 17 lays over the flank 24 when part 16 has been buckled as shown in Figure 1. In these Figures 1 to 3, the tooth is shown as having two depending portions 8 and 10 forming a recess therebetween to receive part 15 of the locking member whereas in Figures 4 and 5 the tooth has only one depending portion 8 and the part 15 is made almost as long as the part 16. This provides a somewhat larger opening between the bottom of the tooth and the adapter to allow insertion of the locking member.The rear end of part 15 is bent down to form a tab 19 which acts in the same way as depending portion 10, that is to say it prevents that portion of part 16 between the ramp 24 and the free end from buckling upwards when the free end is struck to buckle the portion of reduced thickness down into the recess 12. As shown in Figures 4 and 5 the resilient middle part 17 extends over the length of part 15 which itself extends to the edge of the tooth.

Thus, the locking member shown in Figures 1 to 3 must be set in place at the same time as the tooth, and it is therefore an advantage to have it joined to the tooth whilst the locking member shown in Figures 4 and 5 can be inserted in place afterwards.

The locking member can, for instance, be fastened to the tooth at the factory by means of gluing, or in some other appropriate way.

By making the parts 15 and 16 of the locking member of different widths, and making the width of the opening 7 and the recess 12 correspond to these different widths, the locking member can be prevented from being inserted the wrong way around.

This applies particularly to the embodiment shown in Figures 4 and 5.

Claims (12)

1. A locking member comprising two elongate plates spaced apart by a resilient element, one of said plate having a portion of reduced thickness between one end of said plate and said resilient element, said portion being adapted to buckle out of the plane of said one plate away from the other plate on a force being applied to said one plate so that part of said one plate between the opposite end thereof and the portion of reduced thickness is canted at an angle to that part of said one plate between said one end and said portion of reduced thickness when said member is inserted in an opening between two components which are required to be locked together by said member.

2. A locking member as claimed in Claim 1, wherein said resilient element comprises a block of resilient material secured to said plates, said portion being located between said one end and the position on said one plate where said block is secured thereto.

3. A locking member as claimed in Claim 1 or Claim 2, wherein the ends of the other plate are bent downwards towards said one plate.

4. A securing member for teeth for excavators, loaders, scarifiers or dredge cutters which are removably applied to a holder, the design of which determines the position of the tooth in all directions except the one from which the teeth are exchanged, and in which direction the position of the tooth is determined by the securing member, characterized in that the securing member, which is intended to be inserted into an opening from the same direction as the tooth is exchanged, which extends between the tooth and the holder and farthest in is delimited by a stopping edge made in the tooth and which against the mouth has a blocking edge facing a stopping edge made in the holder, consists of longitudinal edge parts made of metal which are held together by an elastic middle part, particularly made of rubber, which is glued or in some other way which is known in itself is fastened to the two edge parts, and at least one of these edge parts having two grooves located crosswise at a distance from each other serving as buckling indications, of which the end that is intended to be nearest the securing member as the inner crosswise edge is cut down into the side of the edge part facing the elastic middle part at a distance from said end which is somewhat less than the distance between the stopping edge of the tooth and the blocking edge of the holder, while the other groove is cut down into the other side of the edge part at some distance from the first groove.

5. A securing member according to claim 4 characterized in that the buckling grooves are made with a sharply cut down flank facing the adjacent side of the edge part and such a slightly sloping flank in the opposite direction that the respective groove ends entirely only on a level with the sharply cut down flank of the next groove.

6. A securing member according to claim 5, characterized in that the buckling grooves are made in such a way that between their sharply cut down flanks a connecting part with uniform thickness is formed which runs from one broad side of the edge part on a level with one of these sharply cut down flanks to the other broad side of the edge part on a level with the other sharply cut down flank.

7. A securing member according to any one of the foregoing claims, characterized in that only one of the edge parts is provided with buckling grooves and that the other edge part, when not subjected to a load, has its inner end protruding somewhat in front of the inner end of the edge part provided with buckling grooves.

8. A securing member according to any one of claims 4 to 7, characterized in that it is somewhat wedge-shaped from the end intended to be the inner end towards the outer end.

9. A securing member according to any one of claims 4 to 8, characterized in that the edge part provided with buckling grooves protrudes some what behind the other edge part.

10. A securing member according to any one of the foregoing claims, characterized in that it is intended to be inserted in the opening intended for it from the front in the working direction of the tooth.

11. A securing member according to any one of claims 4 to 10, characterized in that only one of the edge parts has the grooves serving as buckling indications and that the other edge part and the elastic middle part only has a length corresponding to the distance up to a level with the first groove in the other edge part.

12. A securing member according to claim 11, characterized in that the edge part which does not have any buckling grooves and that the middle part having the same or a somewhat shorter maximum length has a length adapted so that the part of the securing member which they together constitute fits into a cavity in the tooth, the inner cross-wise edge of this cavity then consisting of the stopping edge of the previously mentioned tooth, while its outer crosswise edge consists of a cleat on the tooth which outwards delimits the groove intended for the securing member with the exception of a portion which substantially corresponds to the thickness of the edge part provided with buckling grooves.