AU5066602A - Locking pin for ground engaging tool components - Google Patents

Description

1 LOCKING PIN FOR GROUND ENGAGING TOOL COMPONENTS BACKGROUND OF THE INVENTION This invention relates to locking pins for ground engaging tool components.

A large proportion of the machinery used in earth moving operations utilise buckets. The teeth attached to the lips of such buckets are generally subject to considerable wear and it is therefore necessary to replace these teeth, or at least portions of them, periodically.

For this reason a number of methods have been developed for releasably attaching ground engaging teeth to the lips of buckets of various earth moving machinery. In some of these methods a series of nosepieces are connected to the lip of a bucket, side by side, and an adaptor is used to releasably connect a tip to each nosepiece. A shroud may also be attached to adjacent nosepieces to provide a wear surface between successive teeth, if desired SUMMARY OF THE INVENTION According to an aspect of the present invention there is provided a one-piece locking pin for locking together two ground engaging tool components which are engageable with one another in a spigot-and-socket fashion and which when engaged in this fashion include aligned apertures for locking the tool components together, the locking pin comprising: 2 a generally elongate shank which is shaped and sized to pass through the aligned apertures in the tool components; a resilient locking projection in the form of a non-symmetrically shaped head which extends laterally from the shank, which is shaped and sized to pass through only one of the aligned apertures in the tool components, and which is specifically designed to be rotated, under a predetermined torque, into a locking recess in a side wall of the tool component aperture through which the head can pass so as to be compressively captured within the locking recess for locking the locking pin to the tool components; and a formation on the locking pin which is engageable with a rotatable member for rotating the head into the locking recess.

Preferably the shank is formed from steel and the head is formed integrally with the shank from a high density polyurethane compound. The need may extend laterally from one side only of an imaginary plane which cuts the shank into two equal halves along a longitudinal axis of the shank.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which: FIG. 1 shows a front perspective view of a tooth assembly according to the invention; FIG. 2 shows a front perspective view of a nosepiece according to the invention; FIG. 3 shows a rear perspective view of an adaptor according to the invention; 3 FIG. 4 shows a front perspective view of the adaptor of FIG. 3; FIG. 5 shows a rear perspective view of a tip according to the invention; FIG. 6 shows a front perspective view of the tip of FIG. FIG. 7 shows a side view of the tip of FIG. FIG. 8 shows a top plan view of a locking pin according to the invention; FIG. 9 shows a front view of the locking pin of FIG. 8; and FIG. 10 shows a perspective view of the locking pin of FIG. 8.

DESCRIPTION OF A PREFERRED EMBODIMENT Figure 1 shows a perspective view of ground engaging tool components in the form of a tooth assembly 10 which is connectable to the lip of a bucket (not illustrated) of an earth moving machine. Typically, a series of such assemblies are arranged side by side on the lip of the bucket to provide a plurality of spaced apart teeth on the bucket.

The tooth assembly 10 comprises a nosepiece 12, an adaptor 14 releasably connected to the nosepiece, and a tip 16 releasably connected to the adaptor.

Referring to Figure 2 of the drawings, the nosepiece 12 has a front face 20 and upper and lower faces 22 and 24 extending back from the front face to form a shallow U-shaped formation which defines a channel 26. The channel 26 is sized to fit over the lip of a conventional bucket for earth moving machinery. A central rib 28 projects outwardly from the upper and lower faces 22 and 24, and forwardly from the front face as shown. The rib 28 includes a spigot 30 which also projects forwardly.

4 The spigot 30 has two side faces 32 and 34, a bottom face 36 and a top face 38 which all taper inwardly towards the free end 40 of the spigot. A tapered groove 42 extends rearwardly from the free end 40 along each of the side faces 32 and 34. The grooves 42 have side walls 46 and 48 which converge towards one another as they move away from the free end 40 of the spigot.

The bottom face 36 of the spigot 30 defines a generally circular aperture (not shown) for receiving a locking pin (also not shown).

Figures 3 and 4 illustrate the adaptor 14 which is connectable to the nosepiece 12. The adaptor 14 is in the form of a hollow, steel, generally wedge-shaped body which has four sides 52, 54, 56 and 58. The four sides converge towards one end 59 of the adaptor. On the inside of each of the sides 54 and 58 there is a wedge 60 which is shaped to engage with the groove 42 on the nosepiece 12. Accordingly, the side walls of the wedges 60 converge complementally to the side walls of the grooves 42.

The side 56 of the adaptor 14 defines an aperture 62 for receiving a nonsymmetrical head of a locking pin (not shown). The shape of the aperture will be described in more detail below.

An adaptor spigot 64 projects from the end 59 of the adaptor 14. The adaptor spigot is similar in shape to the nosepiece spigot 30 and also has sides which taper towards the free end 66 thereof. Also similarly to the nosepiece spigot, the adaptor spigot 64 has a pair of tapered grooves 68 which are formed on the sides 70 and 72 of the spigot. Unlike the nosepiece spigot, however, the adaptor spigot defines a generally circular aperture 74 on each side 70 and 72, at the rearmost end of each groove 68.

The tip 16 is illustrated in Figures 5 to 7 of the drawings and is also in the form of a hollow, steel, substantially wedge-shaped body. In the case of the tip, the steel may include tungsten steel inclusions to improve the wear characteristics of the tip. The tip has four-wear faces 80, 82, 84 and 86 which are designed to contact the earth and rubble being loaded into the bucket. On the inside of the wear faces 82 and 86 a tapered wedge 88 extends in a similar fashion to the wedge 60 on the adaptor 14.

Furthermore, the wear faces 82 and 86 also define non-symmetrical apertures 90 for receiving the non-symmetrical head of a locking pin (not shown).

In Figures 8 to 10 there is shown a locking pin 100 which has a steel, circular cylindrical shank 102 and a non-symmetrical head 104 in the form of a cam formed from a high density polyurethane compound having a Shore hardness of between 80 and The head 104 is cast integrally with the shank 102. The locking pin 100 includes a recessed formation 106 which is shaped to receive a key or the like so that the locking pin can be rotated.

Referring again to Figure 7 of the drawings, the apertures 90 are generally oval or egg-shaped, as shown, to receive the heads 104 of locking pins 100. Each aperture includes a recessed portion 108 on a portion of the side wall of the aperture remote from each wear face 82 and 86 into which the head 104 can be turned. Accordingly, once the locking pin has been slid into the wear face 82 and the head 104 has been turned into the recess 108 the locking pin cannot be slid out of the wear face unless it is first rotated out of the recess.

The recess 108 also includes a node 110 at the entrance thereto so that a predetermined torque is required to rotate the head 104 into this recess. Once the head has been rotated into the recess, it is captured there by the node 110. The size of the recess is slightly smaller than that of the head so that the resilient material of the head is compressed when it is captured in the recess.

The shape of the aperture 62 is similar to that of the aperture 90, while the shape of the apertures 74 in the spigot 64 and the aperture in the bottom face 36 of the spigot 30 are generally circular.

In use, the nosepiece 12 is connected to the lip of a bucket (not illustrated) by a suitable means, such as by welding. Thereafter, the adaptor 14 is slid onto the spigot of the nosepiece 12 so that the wedges 60 lie within the grooves 42 and the aperture 62 is aligned with the aperture on the bottom face 36 of the spigot 30. The wedges and grooves are designed so that the side walls of the wedges bear against the side walls of the grooves when the tapered faces 32, 34, 36 and 38 mate with the tapered sides 52, 54, 56 and 58. In this position the aperture 62 in the adaptor is aligned with the corresponding aperture in the nosepiece.

At this stage a locking pin (as illustrated in Figures 8 to 10 of the drawings) is fitted into the aligned apertures so that the shank 102 passes through both apertures but the head 104 passes through the aperture 62 only and bears against the bottom 7 face 36. Thereafter the head of the locking pin 100 is rotated, with the aid of a key orthe like, into the recess of the aperture 62 so as to be captured in the recess for locking the adaptor 14 to the nosepiece 12. The adaptor 14 is then substantially fixed with respect to the nosepiece 12 by virtue of the relatively close tolerance fit between the adaptor and the nosepiece. Furthermore, the adaptor 14 is wedged onto the nosepiece as a result of the compressive force on the resilient head of the locking pin 100 in the recess.

However, although the interaction between the tapered wedges 60 and the tapered grooves 42 serves to resist creep between the mating tapered faces of the adaptor 14 and the nosepiece 12, the adaptor is capable of being forced slightly further onto the nosepiece when a working load is applied to the components so as to be wedged more securely onto the nosepiece.

Once the adaptor 14 has been locked to the nosepiece, the tip 16 is slid onto the adaptor spigot 64 in a similar fashion to that described above with respect to the adaptor and the nosepiece so that the wedges 88 on the tip lie within the grooves 68 on the adaptor. Once again, the apertures 90 and 74 are aligned with one another when the side walls of the wedges 88 bear against the side walls of the grooves 68.

A locking pin similarto that illustrated in Figures. 8 to 10 is then inserted into the apertures 90 and 74 as described above and the head of the locking pin is rotated into the recess 108 so as to lock the tip 16 onto the adaptor 14. The tip and adaptor are also capable of slight additional creep with respect to one another under a working load until the two are wedged securely to one another.

8 The locking pin serves mainly to initially secure the components together until, under a working load, the components are securely seated upon one another. In this way movement of one of the components relative to the others is substantially eliminated and shock loading is considerably reduced.

When a series of adaptors and tips have been connected to a number of nosepieces on the lip of a bucket in the manner described above, a series of spaced apart teeth are securely wedged to the lip of the bucket.

Since the side walls of the grooves and wedges taper in an opposite sense to that of the opposed tapered faces of the spigots and sockets, the wedging action for securing the components together is improved.

Although the invention has been described with particular reference to tooth assemblies for attachment to the lips of buckets of earth moving machinery, it should be appreciated that the invention is not limited to such tooth assemblies and may also be applied in the connection of various other ground engaging tool components.

Claims (4)

1. A one-piece locking pin for locking together two ground engaging tool components which are engageable with one another in a spigot-and-socket fashion and which when engaged in this fashion include aligned apertures for locking the tool components together, the locking pin comprising: a generally elongate shank which is shaped and sized to pass through the aligned apertures in the tool components; a resilient locking projection in the form of a non-symmetrically shaped head which extends laterally from the shank, which is shaped and sized to pass through only one of the aligned apertures in the tool components, and which is specifically designed to be rotated, under a predetermined torque, into a locking recess in a side wall of the tool component aperture through which the head can pass so as to be compressively captured within the locking recess for locking the locking pin to the tool components; and a formation on the locking pin which is engageable with a rotatable member for rotating the head into the locking recess.

2. The locking pin according to claim 1, wherein the shank is formed from steel and the head is formed integrally with the shank from a high density polyurethane compound.

3. The locking pin according to claim 1 or claim 2, wherein the head extends laterally from one side only of an imaginary plane which cuts the shank into two equal halves along a longitudinal axis of the shank.

4. A locking pin substantially as described herein in the detailed description with reference to the drawings. DATED THIS TWENTY-SIXTH DAY OF JUNE 2002 CATERPILLAR SARL BY PIZZEYS PATENT AND TRADE MARK ATTORNEYS