EP0203315B1

EP0203315B1 - Teeth for use with earth moving equipment

Info

Publication number: EP0203315B1
Application number: EP86104482A
Authority: EP
Inventors: George Paizes
Original assignee: Gamma Lock Pty Ltd
Current assignee: Gamma Lock Pty Ltd
Priority date: 1985-04-03
Filing date: 1986-04-02
Publication date: 1991-01-23
Anticipated expiration: 2006-04-02
Also published as: ES8702556A1; IL78413A0; EP0203315A2; ES554083A0; DE3677056D1; NZ215680A; EP0203315A3

Description

This invention relates to sacrificial teeth for use with earth moving equipment such as a bull-dozer, grader or ditcher.

Background to the Invention

There are two main types of such teeth. There is a tooth which is largely hollow and which releasably fits on to an adapter that is in the form of a point. Such a tooth is hereinafter called a "hollow tooth". A second type of tooth has a solid working end and a root section that is secured to, for example, a bucket. Such a tooth is hereinafter called a "solid tooth".
A hollow tooth is generally fitted on to the adapter and is secured thereto by a fastener comprising a pin which passes through the point and is engaged in apertures in ears on the tooth that run alongside the adapter. Thus the adapter will be the inner part and the tooth will be the outer part fitting thereon.
Solid teeth are generally in one of two forms.
In one form, the root section is divided horizontally into two root parts between which is received the bucket and the root section is secured to the bucket by a suitable fastener. This type of tooth is hereinafter called a "split solid tooth". A second form of solid tooth has a root section which fits into an adapter in the form of a tooth socket secured to the bucket. The root section has a transverse passage therethrough, and the adapter has a pair of side apertures which, when the root section is homed in the adapter, register or substantially register with the passage. The fastener is located within the passage and projects into the said side apertures to retain the root section within the tooth socket, the latter being the outer part surrounding the root section which constitutes the inner part. The latter tooth is hereinafter referred to as a "shanked solid tooth".
Originally solid teeth were split solid teeth and these were attached by being bolted on to the bucket. This is fairly satisfactory. However after the bucket has been used for some time, the threads on the bolts are burred over and generally sand and dirt packs on to the tooth making it extremely difficult to remove the bolts. To remove a worn tooth, therefore, it is usual to cut the bolts with an oxyacetylene cutter. This means that the earth moving equipment, which is a substantial and expensive piece of equipment has to be taken into the workshop to have the worn teeth cut off and to replace them with new teeth. As can be appreciated this is costly in down time of the equipment and there are difficulties in the cutting operation. Alternatively the oxy-acetylene cutter and necessary gas bottles have to be taken into the field which in practice was not satisfactory.
Subsequently, the shanked solid tooth and its assembly was provided as described in U S Patent 3 879 867. In this arrangement, the fastener comprises a rubber/steel key that secures the root section to the socket This key comprises two steel members extending over the entire length of the key and having an elastomeric element therebetween. The key is wider than the side apertures and passage in the root. It is hammered into the side apertures through the socket and through the passage in the root compressing the elastomeric element. When the tooth has worn down, the key is hammered out and the stub of the tooth can be removed.
A disadvantage of the system described in the preceding paragraph is that the side apertures and the passage must be accurately dimensioned. Furthermore it is necessary to have at least one loose part in addition to the tooth. This can cause difficulties in the field as it may be that a contractor has teeth to affix to an earth moving apparatus but does not have available the necessary fasteners.
Australian patent 558724 (Serial AU-B-28449/ 84) shows a fastener for multi part cutting edges of scraper blades for earth moving equipment. The fastener which is arranged transversely to the direction of relative movement between the parts for removal comprises a pair of legs connected together by a compression spring which biasses the legs apart from an inner position to an outer position and which has its ends either cast or welded to the legs. These legs have notches to engage similarly contoured profiles in the side walls of an adaptor over which the cutting edge fits. A specially formed tool is required to apply pressure to the sides of these legs to compress the compression spring and thereby to permit the lock to be removed. The manufacture of the fastener is complex and as described in the specification is probably impossible as the compression spring would be likely to be annealed during the welding or casting operation. It is doubtful whether this fastener could be used with shanked teeth either as described or at all.

Statement of Invention

According to one aspect of the present invention there is provided a fastener for a tooth for use with earth moving equipment comprising a pair of fastening members that are mounted to pivot relative to one another from an inner position to an outer position and biassing means, preferably in the form of an elastomeric element, preferably comprising rubber or neoprene, to bias the fastening members apart from the inner positions to the outer positions, the fastener further comprising an abutment member against which the said fastening members butt in such a way as to be able to pivot relative thereto. Preferably the said members are provided with rounded ends and preferably the said abutment member has rounded recesses within which the said ends are received so as to be able to pivot as aforesaid.
In use, the fastener will be inserted in a passage in the inner part prior to it being received in the outer part as defined above. When the fastening members are in the inner position, the inner part can be received in the outer part and when the fastening members are adjacent openings in the outer part, they will be biassed outwardly into the outer position so that one engages the sides of the openings and the other will act against the abutment member thereby to secure the inner part into the outer part. The said fastening members preferably are provided with weaknesses so that when struck with a blow substantially at right angles thereto the members will tend to break so as to facilitate the removal of the fastener from the tooth and adapter.
Holding means are preferably provided to hold the fastener in the passage. Such holding means preferably comprises a projection formed on the passage and a recess in the elastomeric element into which the projection is received to prevent movement of the fastener transversely to the passage. Preferably too the abutment member is slidably located against one side of the passage and the said members butt in such a way as to be able to pivot relative to each other.
According to another aspect of the invention there is provided the combination of a shanked solid tooth or hollow tooth with an adapter therefor and a fastener as set forth above connecting the tooth to the adapter.
Embodiments of the invention will now be described with reference to the accompanying drawings.

Short Description of the Drawing

In the drawings:-

Figure 1 is an underplan view partially in section of a shanked solid tooth of the invention in position in an adapter socket, the side of the bucket and the cover plate being omitted for clarity,
Figure 2 is a section on line 2-2 of Figure 1
Figure 3 is a section on line 3-3 of Figure 2
Figure 4 is an end view of a tooth of the invention in its adapter, and
Figures 5 and 6 are respectively a side view of the rear of a hollow tooth of the invention and a section on line 6 - 6 of Figure 5.

Description of the Preferred Embodiment

Referring now to Figures 1 and 2 there is shown a solid shanked tooth 10, an adapter in the form of a tooth socket 12 for receiving the tooth 10 as will be described, and a fastener 14 for retaining the tooth 10 in the adapter. The adapter socket 12 comprises a "U"-shaped member, the arms 16 of which are welded to the bottom plate of a bucket (not shown).
The tooth 10 has a spade-shaped working end 20 terminating in an inner or rear wall 20a from which extends a root section or shank 22 which is received in the socket 12. The root section or shank 22 has a transverse passage 24 therethrough. The passage 24 is defined by a recess having a base 26 and transversely extending plane side walls 28a and 28b. The passage is of increased width at its upper ends to form aligned platforms 30. A steel plate 34 rests on these platforms 30 to form a cover for the passage 24.
The adapter socket 12 has a pair of aligned side apertures 36 formed by "U"-shaped cut-outs in the arms 16 and by the said bottom plate 18. The side apertures 36 have longitudinally spaced end walls 38 and 40. The inner corner 39 of each wall 38 is rounded for the purpose which will become apparent. When the root section 22 is homed in the socket 12, these apertures 36 are adjacent to the passage 24.
The fastener 14 comprises a pair of aluminium fastening members 42, an elastomeric, rubber or neoprene, trapezoidal block 44, and an abutment plate 46. The elastomeric block 44 is in the shape of the frustum of an isosocles triangle. It serves as a biassing means for the members 42 as will be described. The abutment plate 46 runs along the length of and slidably abuts against the side wall 28a of the passage 24 remote from the working end 20 of the tooth 10. The fastening members 42 run generally in the direction of the shank 22. The ends 48 of the fastening members 42 adjacent to the abutment plate 46 are rounded and are received within semi-circular recesses 50 in the abutment plate 46. The outer sides of the fastening members 42 are constituted by projections 52 which are generally triangular in shape. Each projection has a forward end wall 54, which is slightly rounded and which is inclined as will be described for the purposes that shall emerge, and a straight rear side wall 55. There is a neck or line of weakness 56 between the rounded ends 48 and the thicker portions of the projections 52. The inner surfaces 58 of the fastening members 42 are flat over most of their length and butt against the sides of the elastomeric block 44 which are vulcanized to these surfaces. At the junction 59 between the ends 48 and the projections 52 and the ends 48 and the surface 58 only a very small radius or none at all, exists.
A low, narrow, longitudinally extending ridge 60 is centrally located standing up from the base 26 of the passage 24. A longitudinal groove 62 is provided in the block 44 and this receives the ridge 60. The engagement of the ridge 60 in the groove 62 prevents the fastener 14 from moving transversely in the passage 24.
The elastomeric block 44 serves as a biassing means tending to bias the fastening members 42 to pivot relative to one another about their rounded ends 48 each from an inner position, when the block is compressed, to an outer position when the block 44 is in its rest position.
When the fastening members 42 are in their inner positions, they lie substantially wholly within the passage 24. When the fastening members 42 are in their outer positions, the projections 52 project beyond the passage 24 to lie between the end walls 38 and 40 of the side apertures 36. The forward ends of each fastening members 42 at the junction of the forward end wall 54 and the surface 58 however are wholly contained within the passage 24.
The forward end 54 of each projection 52 engages the inner corner 39 of the wall 38 of the aperture closer to the working end 20 of the tooth.
The tooth 10 can easily be fitted into the socket 12 by feeding the root section 22 into the mouth 64 of the socket 12 until the rear side walls 55 of the projections 52 engage the mouth. Further inward pressure will cause the walls 55 to swing the fastening members 42 inwards compressing the block 44 so that the fastening members 42 move into their inner positions enabling the shank 22 to move into the socket 12. When the shank 22 has homed into the socket 12 and the rear wall 20a butts against the mouth 64 of the socket 12, the projection 52 will be opposite the apertures 36. The block 44 will now bias the fastening members 42 outwardly into their outer positions so that the projections 52 enter the apertures 36 and the front walls 54 engage the rounded inner edges 39 of the end walls 38.
The shank 22 will now be firmly held in place in the socket 12, rearward movement being inhibited by the engagement of the rear wall 20a of the working end 20 with the socket 12 and forward movement being inhibited by the engagement of the walls 54 of the fastening members 42 with the walls 38.
It will be noted that the angle of the front face of the end wall 54 is so chosen that any resultant force tending to remove the shank 22 from the socket 12 will run directly along the length of each fastening member 42 through the centre of the portion 48 (or slightly inside it) on to the abutment plate 46. Very substantial compressive forces, which are in excess of any forces that would normally be encountered in practice, can thus be absorbed by the fastening members 42 so that the possibility of the tooth 10 being pulled out of the socket 12 is virtually non-existent.
Furthermore the shapes of each of the front walls 54 and the rounded shape of the corner 39 of the end wall 38 are such that forces emanating from the end wall 38 will not tend to pivot the fastening members 42 either inwardly or outwardly but will only be conveyed directly down the length of the fastening members as mentioned above.
When the working end 20 of the tooth 10 has worn down, the tooth 10 must be taken out of the socket 12. To do this, the fastener 14 must be removed which is effected by a sharp hammer blow being struck against the abutment plate 46 transversely to the root section 22. This will tend to move the abutment plate 46 relative to the fastening members 42 and in turn to cause these to fracture along the lines of weakness 56. This is ensured because of the narrow neck and the sharp junctures 59 which latter form stress points. Also the elastomeric block 44 will tend to tear along a continuation of the groove 62. When this happens, the parts of the fastener 14 can simply be pushed out of the passage 24. The shank 22 of the tooth 10 can now be removed from the socket 12, possibly with the assistance of a hammer blow on the inner end 68 of the shank 22. A new tooth is now attached in the manner described above.
It will be noted that only hand pressure is needed to insert the shank 22 into the socket 12 unless excessive dirt remains in the socket. Then a light hammer blow would be all that is necessary for the purpose.

Description of a Hollow Tooth of the Invention

As shown in Figures 5 and 6, a hollow tooth 90 has a hollow rear end 92 in which is received an adapter 94 in the form of a point. A transverse passage 96 is provided through the adapter and in this is received a fastener 98.
The fastener 98 is a separate loose item, but is otherwise substantially identical to the fastener 14 and includes fastening members 100, having outer projections 102, and an elastomeric block 104 therebetween to which the members are vulcanized. The rounded ends of the members 100 are received in rounded recesses in an abutment plate 106. The inner end of the block 104 is also vulcanised to the abutment plate 106 thus creating a complete unit which holds together during normal handling.
The tooth 90 has ears 110 which lie on either side of the adapter 94. Each ear 110 has an aperture 112 which, when the tooth 90 is homed on to the adapter 94, is aligned with the passage 96.
The tooth has internal grooves (not shown) extending from the ears 110 to the apertures 112, to receive the projections 102 as will be described.
In use, the fastener 98 is first placed in the passage 96 and roughly centralised therein. The tooth 90 is now fitted on to the adapter 94 until the said grooves engage the projections 102. Further pressure will compress the block 104 moving the fastening members 102 into their inner positions until the tooth 90 is homed on the adapter 94. Now the projections spring out under the bias of the elastomeric block 104 to engage the apertures 112 and to hold the tooth 90 on the adapter 94. Removal of the fastener 98 is as described with reference to Figures 1 and 2.

General

I have found that each of the above described teeth of the invention can be fitted easily to its adapter.
The invention can be used with advantage on all sizes of teeth from those having a mass of 2 kg to 70 kg or even more.
I have further found that the fasteners will be positively held in the passage of the shanked solid teeth so that they cannot be removed therefrom inadvertently. However the fastener can be readily removed as described above when the working end is worn down.
Because the shanked solid tooth 10 is provided with a fastener 14 in the passage 24, it will not be necessary to carry separate fasteners 12 in stock. Of course this advantage does not apply with the hollow tooth of the invention.
The invention is not limited to the precise constructional details hereinbefore described and illustrated in the drawings. For example in the embodiment of Figure 4, a ridge may engage in a central slot in the block to hold the fastener in position. The fastening members may comprise other material having high compressive strength, but low strength in shear. The invention may also be used with drag line shovels and other ground engaging tools.

Claims

1. A fastener (14, 98) for a tooth (10,90) for earth moving equipment such as a bull-dozer, grader or ditcher comprising a pair of fastening members (42, 100) that are mounted to pivot relative to one another from an inner position to an outer position and biasing means (44, 104) to bias the members apart from inner positions to outer positions characterised by an abutment member (46, 106) against which the said fastening members (42, 100) butt in such a way as to be able to pivot relative thereto.

2. A fastener as claimed in claim 1 characterised in that the biassing means comprises an elastomeric block (44, 104) vulcanized to the fastening members (42, 102).

3. A fastener as claimed in claim 1 characterised in that the said members are provided with rounded ends (48) and in that the said abutment member (46) has rounded recesses (50) within which the said rounded ends are received so as to be able to pivot as aforesaid.

4. A fastener as claimed in any one of the preceding claims characterised in that the said members (42) are provided with weaknesses so that when struckwith a blow at right angles thereto the members break so as to facilitate the removal of the fastener (14) from the tooth and adapter.

5. A shanked solid tooth (10) having a root section (22) which in use fits into an adapter (12) in the form of a tooth socket secured to a bucket (18), the root section having therethrough a transverse passage (24), and within the passage a fastener (14) to hold the tooth in the adaptor, characterised in that the said fastener (14) is a fastener as claimed in any one of the preceding claims and in that the fastening members (42) are arranged in such manner that when the said members (42) are in their inner positions, they are wholly or substantially wholly contained within the passage (24).

6. A shanked tooth as claimed in claim 5 characterised in that the abutment member (46) is slidably located against one side (28a) of the passage (24).

7. A tooth as claimed in claim 5 or claim 6 characterised in that holding means (60) is provided for holding the fastener within the passage.

8. A tooth as claimed in claim 7 characterised in thatthe holding means comprises a projection (60) from the passage (24) and a recess (62) in the elastomeric block (44) into which the projection is received to prevent movement of the fastener (14) in the passage.

9. The combination of an adapter (12) with a shanked solid tooth (10), the adapter being in the form of a substantially "U"-section tooth socket secured to a bucket (18) and having aligned openings (36) in its arms (16) adjacent the bucket and the shanked solid tooth (10) having a root section (22) having therethrough a transverse passage (24), the root section in use fitting into the adapter (12) with the passage (24) aligned with the said openings (36) and being held therein by a fastener (14) characterised in that the tooth is a tooth as claimed in any one of claims 5, 6, 7 or 8 and in that when the said fastening members (42) are in their outer positions, they project into the openings (36) and butt against the ends (38) of the openings.