BUCKET TOOTH LOCKING PIN

Abstract

A system to attaching a tooth to a bucket shank comprises a ring seat in the shank having a cam. A locking ring having a corresponding cam is seated in the seat and has an interior channel bounded by shoulders. A locking pin of a dissimilar material to the ring includes a lobe sized to correspond to the channel. Once inserted through apertures in the tooth and the shank, the pin may be rotated to force the lobe over the shoulders and to be housed in the channel to securely hold the pin in place.

Description

FIELD OF THE INVENTION

This invention relates to loading buckets. In particular, this invention relates to teeth used on loading buckets and means for retaining the teeth on the bucket.

BACKGROUND OF THE INVENTION

A loading bucket for heavy machinery typically includes a number of teeth on the ground-engaging surface of the bucket.

As shown in the prior art images of FIGS. 1 and 2, a bucket tooth 12 is installed on a shank 10 in a mating relationship so that the stresses on the tooth are conveyed over relatively large and angled contact surfaces 14 to the shank. A lock pin 16 extends through both the shank 10 and the tooth 12 to ensure that the tooth remains on the shank during use.

Referring to FIGS. 2 and 4, an aperture 18 extends through the sides of the tooth 12 and through the shank 10 to receive the pin 16. The outer edges of one side of the aperture are formed with a seat 20 to accommodate a locking ring 22. Referring to FIG. 5, the prior art pin 16 includes a larger diameter portion 17 and a reduced diameter portion 19 that is sized to receive ring 22. Locking ring 22 seats in the reduced diameter portion 19 of the pin 16 in the assembled configuration. Locking ring 22 serves to hold the pin 16 in the aperture 18 when the tooth 12 is installed over the shank 10. As seen in FIG. 3, ring 22 includes a cut 23 with a corresponding gap 25 to allow the ring 22 to be more easily deformed when being fitted over the regular diameter portion of the pin 16 until it reaches the reduced diameter portion 19. A ring sleeve 24 may be used to cover the ring 22, as shown in FIGS. 3 and 4. Note that FIG. 4 does not show the pin 16 or the shank 10.

The assembly of the tooth to the shank involves first inserting the locking ring 22, usually along with ring sleeve 24 into the seat 20 of the shank 10. The tooth 12 is then installed over the shank 10. Locking pin 16 is then inserted into the aperture 18 and the pin is hammered into place through the ring 22 which deforms radially outward around larger diameter portion 17 of the pin. The pin 16 is pushed through until the ring 22 seats in the reduced diameter portion 19 of the pin to result in the assembly shown in FIG. 2.

According to the prior art, the locking pin 16 and the ring 22 are typically made of similar materials. As a result, rust tends to set in causing adhesion of the ring to the pin. When it is necessary to change the tooth on a bucket, a hammer must be used to disengage the ring and the pin. In many cases, the difficulty of disengaging it can result in injuries to the operator.

It is therefore an object of this invention to provide a tooth retaining means that is more easily and reliably removed than the aforementioned prior art systems.

This and other objects of the invention will be better understood by reference to the detailed description of the preferred embodiment which follows. Note that not all of the objects are necessarily met by all embodiments of the invention described below or by the invention defined by each of the claims.

SUMMARY OF THE INVENTION

According to the invention, the ring is made of a dissimilar material to the locking pin. The ring is provided with a cam surface that mates with a corresponding cam portion of a ring seat that is provided on the sides of the shank. The cam surface and cam portion of the seat cooperate to prevent the ring from turning in the seat in the event that the pin is rotated.

The pin is provided with a shoulder to abut against one side of the locking ring when the pin is inserted into the apertures of the shank and tooth, thereby preventing the pin from proceeding further through the apertures.

A locking lobe is provided on the pin and a correspondingly sized axial slot is provided on the inside surface of the ring to allow the pin and its lobe to slide through a portion of the ring when the pin is being inserted into the shank and tooth. The ring is further provided with an inner diameter channel that is closed at each end by shoulders adjacent the slot.

The pin is inserted through the ring by aligning the lobe with the slot and inserting the pin until the lobe is aligned with the channel between the shoulders. The pin is then rotated within the ring. The cam portion of the seat holds the ring against rotation, allowing the rotation of the pin to force the locking lobe over one of the shoulders and into the channel. The channel walls prevent the pin from being withdrawn from the ring longitudinally. The pin is thereby effectively held in the assembly by the ring that is retained in the ring seat within the tooth and shank assembly.

In order to disassemble the assembly, the pin is rotated, for example by means of a hex wrench or other corresponding tool, to force the locking lobe back over one of the channel shoulders into position in the ring socket, from where the pin can be withdrawn axially from the ring and from the apertures in the shank and the tooth.

In one aspect the invention is therefore a bucket tooth assembly. The assembly comprises a shank having an aperture extending therethrough. The aperture has an enlarged portion forming a ring seat at one end. The ring seat is partly circular and further has a cam portion. A tooth is adapted to fit over the shank and has aligned apertures in opposed walls of the tooth. A ring is seatable in the ring seat and has a cam portion corresponding to the cam portion of the ring seat. The ring also has an inner wall defining a recess. The is a locking pin for extending through the shank aperture and through at least one of the opposed apertures of the tooth. The locking pin has a protrusion adapted to be retained in the recess of the ring when the pin is disposed in the apertures.

In another aspect, the recess is a channel formed along the inner wall of the ring but extending less than 360 degrees along the inner wall.

In another aspect, the ring further comprises an axially oriented slot whose dimensions accommodate the protrusion on the pin.

In yet another aspect, the slot extends to a portion of the inner wall to which the channel does not extend.

In a sub-assembly aspect of the invention, the invention is a sub-assembly for a bucket tooth assembly. The sub-assembly comprises a shank for receiving a bucket tooth, a ring seat in the shank and a ring shaped and sized to seat in the ring seat, the shapes of the ring seat and of the ring preventing rotation of the ring when it is seated in the ring seat and a locking pin having an element that is selectively securable in a portion of the ring to prevent axial withdrawal of the pin from the ring.

In another aspect, the portion of the ring of the sub-assembly comprises a cavity. In a further aspect, the cavity comprises a channel along a portion of an inner wall of the ring and the element of the locking pin comprises a protrusion on a surface of the pin.

In a different aspect, the invention is a ring for use in a bucket tooth and shank assembly. The ring has a generally circular shape with a portion that engages a surrounding surface so as to prevent rotation against the surface. The ring also has a cavity for receiving and preventing a portion of a locking pin from sliding axially out of engagement with the ring.

In another aspect of the ring of the invention, the portion of the ring is eccentric. In a further aspect, the cavity is a channel along a portion of an inner wall of the ring.

In a different aspect, the invention is a shank for a bucket tooth and shank assembly. The shank has an aperture extending through the shank. The aperture has an enlarged portion forming a ring seat at one end that is generally circular with an eccentric portion.

In yet a different aspect, the invention is a pin for use in a bucket tooth and shank assembly wherein the pin is generally cylindrical and has a frusto-spherical lobe on the surface thereof.

In a method aspect, the invention comprises a method for assembling a tooth to a bucket shank. A ring is placed in ring seat on a bucket shank, the ring and ring seat being respectively shaped to prevent rotation of the ring in the ring seat. A bucket tooth is installed over the shank. A generally cylindrical locking pin having a protrusion on the surface thereof is inserted into apertures in the tooth and the shank such that the protrusion engages and is retained by the ring against axial withdrawal of the pin from engagement with said ring.

In a more detailed method aspect, the ring includes an axially extending slot of a size to accommodate movement of the protrusion along the slot, and a channel on an inner wall of the ring for retaining the protrusion against axial displacement. The step of inserting the pin involves sliding the pin such that the protrusion moves axially along and within the slot, then rotating the pin so as to cause the protrusion to be located within the channel.

The foregoing was intended as a summary only and of only some of the aspects of the invention. It was not intended to define the limits or requirements of the invention. Other aspects of the invention will be appreciated by reference to the detailed description of the preferred embodiments. Moreover, this summary should be read as though the claims were incorporated herein for completeness.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by reference to the detailed description of the preferred embodiment and to the drawings thereof in which:

FIG. 1 is a longitudinal side view of a replaceable bucket tooth installed on a shank according to the prior art.

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1.

FIG. 3 is a perspective exploded view of the ring and sleeve according to the prior art;

FIG. 4 is a cross-sectional view of the shank showing the aperture, the ring seat and the ring and sleeve according to the prior art;

FIG. 5 is a side elevation of the pin according to the prior art;

FIG. 6 is a longitudinal cross-section of the pin according to the preferred embodiment.

FIG. 7 is an end view of the pin according to the preferred embodiment;

FIG. 8 is an isometric view of the ring according to the preferred embodiment of the present invention;

FIG. 9 is plan view of the ring according to the preferred embodiment of the present invention;

FIG. 10 is sectional view taken along lines 10-10 of FIG. 9;

FIG. 11 is a sectional view taken along lines 11-11 of FIG. 9;

FIG. 12 is a sectional view taken along lines 12-12 of FIG. 9;

FIGS. 13 and 14 are isometric views of a ring sectioned along lines 12-12 of FIG. 9;

FIG. 15 is a radial sectional view of the ring of FIG. 9;

FIG. 16 is a side view of the shank showing the ring seat and pin aperture;

FIG. 17 is a longitudinal section view of the shank;

FIG. 18 is a cross sectional view of the shank, ring and pin;

FIG. 19 is a longitudinal side elevation of the shank, pin and ring;

FIG. 20 is a perspective view of the tooth; and,

FIG. 21 is a longitudinal side elevation of the assembled shank, pin, ring and tooth.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 16, 17 and 18 show a shank 50 according to the preferred embodiment of the invention. As best seen in the sectional views of FIGS. 17 and 18, the shank 50 includes an aperture 52 extending laterally through the shank for receiving a pin 58 through the aperture. One side of shank 50 further comprises a ring seat 54 for receiving a ring as will be described below. Ring seat 54 is preferably generally circular but including an eccentric cam portion 56, as is best appreciated by reference to FIG. 16.

FIGS. 6 and 7 show the pin 58 according to the preferred embodiment. Pin 58 may be of steel. Pin 58 includes a shoulder 60 between a larger diameter portion 62 and a smaller diameter portion 64. A locking lobe 66 is provided on the surface of the smaller diameter portion 64 of the pin 58. As will be described below, lobe 66 is sized to be accommodated and seated in a channel formed along the inner wall of the ring. In the preferred embodiment, the lobe is a frusto-spherical protrusion on the surface of pin 58.

The end 68 of the pin 58 may be formed with a hexagonal head 70 to assist in rotating pin 58 when it is being installed or removed from the tooth-shank assembly using a hexagonal wrench or other tool.

A ring 72 is shown in FIGS. 8 to 15. Ring 72 should be of a material that is dissimilar to the material forming the pin 58. In the preferred embodiment, the ring 72 is made of urethane.

Ring 72 is generally circular but its outer perimeter is provided with an eccentric cam surface 74 corresponding in dimensions to the cam portion 56 of the ring seat 54. As a result, when the ring 72 is seated in the ring seat 54, the corresponding cam portions 56 and 74 cooperate to prevent rotation of the ring 72 within the ring seat 54.

The inner wall 76 of the ring 72 is circular save for an axially oriented slot 78 dimensioned to correspond to the dimensions of the locking lobe 66 and to accommodate the locking lobe 66 in the slot 78 and to allow movement of the lobe 66 along the slot 78 as the pin 58 is being inserted through the center of the ring 72.

The inner wall 76 of the ring includes a recess forming a channel 80 along a portion of the inner wall 76. The channel 80 does not however extend 360 degrees around the entire length of the inner wall 76. Instead, it is bounded by shoulders 82 that terminate the channel short of the slot 78, as best appreciated by reference to FIG. 14. As in the prior art, a ring sleeve may also be provided between the ring 72 and the seat 54 but the ring sleeve is not shown in the drawings of the preferred embodiment.

The slot 78 enables the lobe 66 of the pin 58 not to impede the insertion of the pin 58 through the central aperture of the ring 72 provided the pin is arranged so that the lobe 66 is aligned with the slot 78. Once the lobe 66 has been inserted along the slot 78, rotation of the pin 58 forces the lobe 66 to ride over the shoulders 82 to rest within the channel 80. When positioned within the channel 80, the channel prevents the lobe portion of the pin from sliding axially out of engagement with the ring.

Referring to FIG. 20, the tooth 86 is shaped to fit and be installed over the shank 50. Tooth 86 includes aligned apertures 88, 90 in the opposed side walls 92, 94 of the tooth to align with the aperture 52 in the shank.

In order to assemble the unit, the ring 72 (and the sleeve 84 if used) is first seated in the ring seat 54 of the shank 50. The tooth 86 is then installed over the shank 50. The smaller diameter end 68 of the pin 58 is inserted through at least aperture 88 of the tooth 86 and through aperture 52 of the shank from the end that is opposite the ring seat 54. Unless the lobe 66 of the pin 58 happens to be perfectly lined up to enter slot 78 of the ring, the lobe will engage a side of the ring. The user then rotates the pin until the lobe finds and slides along the slot 78. If a sleeve 84 is being used, the shoulder 60 of the pin 62 will then abut the sleeve 84 at 96 to assist in indicating that the pin is inserted to the intended depth for the lobe to be aligned with the channel of the ring.

At this point, the lobe 66 is positioned between the shoulders 82 of the channel 80 of the inner wall 76 of the ring 72. A hex wrench is then used to rotate the pin 58 to urge the lobe 66 over the shoulders 82 and into the channel 80. The pin 58 is thus retained in engagement with the ring 72 by means of the lobe 66 being captive within the channel 80. The pin 58 may still rotate relatively freely within the channel until the lobe 66 reaches one of the channel terminating shoulders 82.

The assembly may be dismantled by again using a hex wrench to rotate the pin 58. As the lobe 66 reaches one of the channel terminating shoulders 82, the pin 58 is forcibly urged into further rotation to cause the lobe 66 to ride across the shoulder 82 and into the slot 78. The ring 72 is otherwise restrained from rotation during rotation of the pin 58 by the seating of the ring's cam surface 74 into the cam portion 56 of the ring seat 54.

The assembly may therefore be both assembled and disassembled with relative ease. The fact that the pin is made of a different material than the ring, and the fact that the pin can rotate within the ring's channel each contribute to minimizing seizing up of the assembly and enhancing the ease of disassembly.

It will be appreciated that prior art tooth designs can be suitable for use with the system of the invention. A prior art tooth design may be assembled about a sub-assembly according to the invention comprising a shank with a ring seat as described above, a ring with a recess as described above and a pin with a protrusion as described above.

In the foregoing specification, the invention has been described with reference to specific embodiments thereof. However, the scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims

1. A bucket tooth assembly comprising: a shank having an aperture extending therethrough;said aperture comprising an enlarged portion forming a ring seat at one end of said aperture;said ring seat being partly circular and further having a cam portion;a tooth adapted to fit over said shank, said tooth having aligned apertures in opposed walls of said tooth;a ring seatable in said ring seat, said ring having a cam portion corresponding to said cam portion of said ring seat;an inner wall of said ring defining a recess;a locking pin for extending through said aperture of said shank and at least one of said opposed apertures of said tooth;said locking pin comprising a protrusion adapted to be retained in said recess when said locking pin disposed in said aperture of said shank and said at least one of said opposed apertures.

2. The assembly of claim 1 wherein said recess is a channel formed along said inner wall, said channel extending less than 360 degrees along said inner wall.

3. The assembly of claim 2 wherein said ring further comprises an axially oriented slot whose dimensions accommodate said protrusion.

4. The assembly of claim 3 wherein said slot extends to a portion of said inner wall to which said channel does not extend.

5. A sub-assembly for a bucket tooth assembly comprising: a shank for receiving a bucket tooth thereon;a ring seat in said shank and a ring shaped and sized to seat in said ring seat, the shapes of said ring seat and of said ring preventing rotation of said ring when the ring is seated in the ring seat; and,a locking pin having an element that is selectively securable in a portion of said ring to prevent axial withdrawal of said locking pin from said ring.

6. The sub-assembly of claim 5 wherein said portion of said ring comprises a cavity.

7. The sub-assembly of claim 6 wherein said cavity comprises a channel along a portion of an inner wall of said ring and said element of said locking pin comprises a protrusion on a surface of said locking pin.

8. A ring for use in a bucket tooth and shank assembly, said a ring having a generally circular shape with a portion that engages a surrounding surface so as to prevent said ring from rotating against said surface, and a cavity for receiving and preventing a portion of a locking pin from sliding axially out of engagement with said ring.

9. The ring of claim 8 wherein said portion of said ring is an eccentric portion thereof.

10. The ring of claim 8 or 9 wherein said cavity is a channel along a portion of an inner wall of said ring.

11. A shank for a bucket tooth and shank assembly, said shank having an aperture extending therethrough, said aperture comprising an enlarged portion forming a ring seat at one end of said aperture wherein said ring seat is generally circular with an eccentric portion.

12. A pin for use in a bucket tooth and shank assembly, said pin being generally cylindrical and having a frusto-spherical lobe on the surface thereof.

13. A method for assembling a tooth to a bucket shank comprising: placing a ring in a ring seat on said bucket shank, said ring and said ring seat being respectively shaped to prevent rotation of said ring in said ring seat;installing a bucket tooth over said shank; and,inserting a generally cylindrical locking pin having a protrusion on the surface thereof into apertures in said tooth and said shank such that said protrusion engages and is retained by said ring against axial withdrawal of said pin from said engagement with said ring.

14. The method of claim 13 wherein said ring includes an axially extending slot of a size to accommodate movement of said protrusion along the slot, and a channel on an inner wall of said ring for retaining said protrusion against axial displacement, and wherein said step of inserting said pin comprises the steps of sliding said pin such that said protrusion moves axially along and within said slot, then rotating said pin so as to cause said protrusion to be located within said channel.