EP0060835A4

EP0060835A4 - Pivot joint.

Info

Publication number: EP0060835A4
Application number: EP19810900868
Authority: EP
Inventors: Harold L Reinsma; Lowell P Verson
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1980-07-03
Filing date: 1980-07-03
Publication date: 1983-12-19
Also published as: BR8009090A; WO1982000181A1; JPS57500893A; EP0060835A1

Abstract

A joint structure (18) including a pivot pin (24; 124) which is locked against movement at its opposite ends (25, 26; 125, 126) in suitable openings (27, 28; 127, 128) in wall members (20, 21; 120, 121). In a preferred form, the pin ends (125, 126) are locked to the walls (120, 121) by a locking plate (159) welded to the pin end and bolted to the wall. In another form, the pin (24) is wedged into locked association with the wall members by wedge members (32, 33). The opening of the walls (20, 21) may be defined by expandable sleeves (29, 30). A clamp (38) is provided for effecting the wedging action and may include a tie rod (39) and threaded elements (43, 45) acting inwardly on the wedge members (32, 33). Sealing structure (46; 146) in each of the disclosed embodiments includes a seal ring (53; 153) having a dynamic sealing engagement with outer surface (55; 155) of the thrust ring (58; 158). The seal ring further has a static seal with a radially inwardly facing surface (57; 157) of the movable member (11; 111) of the joint structure through a metal ring portion (56; 156) of the seal ring.

Description

Pivot Joint

Technical Field

This invention relates to joints and in particu lar to joints having lubricant oil seals.

Background Art

In U. S. Letters Patent 3,997,274, which patent is owned by the assignee hereof, Lowell P. Iverson dis closes a hinge pin construction wherein collets are mounted to the opposite ends of a hinge pin. The collets define wedge surfaces cooperating with inclined wedge surfaces on annular wedge members to urge the collets radially outwardly to be frictionally wedged within an opening in an associated wall member. A conven tional annular static grease seal is provided between the collets and the lift arm bushing. Passages are provided in the collet and wedge member for introducing grease, the passages being selectively closed by suitable plugs. In U. S. Letters Patent 3,347,577 of Marvin J. Carlson et al, a pivot construction is shown utilizing a plurality of dynamic seals such as for use in joints of an articulated vehicle or the like. The joints utilize balls and means for taking up clearance between the ball retainers. Victor Randour shows, in U. S. Letters Patent

3,484,125, an assembly utilizing a stud having adjustable nuts thereon for drawing tempers of associated pins and sockets into tight engagement.

Harold L. Reinsma et al show, in U. S. Letters Patent 3,554,588, which patent is also owned by the assignee hereof, a cartridge-type hinge assembly having annular seals acting between the end bushings of the assembly and a central rotatable bushing. Spacers are provided for preventing longitudinal movement of the rotatable bushings with respect to the pin. The seals are spaced radially outwardly of the spacers. In U. S. Letters Patent 3,841,771, also owned by the assignee hereof, Robert F. Shankwitz et al show a tapered hinge pin assembly utilizing a generally cupshaped collar having an internal taper complementing the external tapered end portion of a hinge pin. The collar is movable into wedged position in a surrounding bore of a wall member by a bolt passing through an enlarged threaded opening in an end wall of the collar in engaging the end portion pf the hinge pin.

In U. S. Letters Patent 3,964,152 of Robert F. Shankwitz et al, which patent is also owned by the assignee hereof, a similar hinge pin assembly is disclosed.

In U. S. Letters Patent 4,022,536 of Donald A. Piepho et al, which patent is also owned by the assignee hereof, still another generally similar hinge pin construction is disclosed.

In U. S. Letters Patent 4,096,957, which patent is also owned by the assignee hereof, Lowell P. Iverson et al show a pivot pin assembly having seals disposed radially outwardly of thrust bearings captured with the seals in grooves in retaining sleeves secured to the opposite ends of the pivot pin. Movement of the pivot pin is limited by a cover plate secured to a bracket of the bucket bracket assembly.

Disclosure of Invention

The present invention comprehends an improved joint structure wherein an annular seal is provided running on the outer diameter of the thrust ring.

In the illustrated embodiment, means are provided for locking a pivot pin of the joint structure to portions of the assembly at the ends of the pivot pin.

The joint structure is adapted for lubrication by means of lubricant oil providing an improved low maintenance, troublefree life of the joint structure. The seal may include a dynamic seal portion acting against the thrust ring and a static seal portion acting against one of the members of the joint assembly. The assembly is arranged to effectively prevent undesirable movement of the pivot pin.

The thrust rings are laterally positioned and mechanically retained by the means for locking the pivot pin. In one embodiment, the locking means includes wedge means acting through an expandable sleeve for wedging the pivot pin to the wall member.

In the illustrated embodiment, the means for drawing the wedging means into wedging disposition comprises a through bolt extending through the pivot pin and provided with threaded means at its opposite ends for threadedly adjusting the disposition of the wedging means at each of the ends of the pivot pin. The joint structure is arranged so that the locking force is effectively diverted from the thrust ring so as to effectively minimize loading thereon.

In the illustrated embodiment, the joint structure defines a wall provided with an opening, a pivot pin having a body portion coaxially within and pivotally carrying a pivotable member and an outer end portion in the opening, an expandable sleeve in the opening coaxially surrounding the pin end portion, an annular wedge coaxially between said sleeve and the pin end portion, a thrust ring coaxially between the sleeve and the pivotable member, an annular seal having a first portion statically sealed to the pivotable member, and a second portion dynamically sealed to the thrust ring, and means urging the wedge axially inwardly to wedge between the pin end portion and sleeve thereby to retain the sleeve in axial abutment with the thrust ring and the thrust ring in axial abutment with the pivotable member and lock the pin end portion to the wall through the sleeve against axially and rotative movement relative to the wall.

A static seal may be provided coaxially between the thrust ring and the pivot pin as desired. Thus, the present invention comprehends an improved joint structure which is extremely simple and economical of construction while yet providing the highly improved low maintenance, troublefree construction.

Brief Description of the Drawing

FIGURE 1 is a fragmentary side elevation of a vehicle structure provided with a joint structure emboyding the invention; FIGURE 2 is a fragmentary enlarged diametric section taken substantially along the line 2-2 of

Figure 1;

FIGURE 3 is a further enlarged fragmentary section of a portion of the joint structure; and FIGURE 4 is a fragmentary section of a portion of the preferred form of the joint structure.

Best Mode for Carrying Out the Invention

In one exemplary embodiment of the invention as disclosed in Figures 1-3 of the drawing, an earth-working vehicle structure, such as a loader, generally designated 10 is shown to include a number of movable arms, such as arms 11 and 12, which are selectively positioned as by positioning devices 13 and 14. II lustratively, a bucket 15 may be pivotally mounted to one end 16 of arm 11 with the disposition of the bucket being controlled by a connecting rod 17 extending between the bucket and movable arm 12. The bucket may be raised or lowered by suitably pivoting the arm 11 about a pivotable joint structure generally designated 18 at the opposite end 19 of the arm 11.

As shown in Figures 1 and 2, the joint structure 18 is mounted to a pair of brackets 20 and 21 at opposite sides of the arm portion 19. Arm portion 19 includes a bushing portion 22 coaxially pivotable about the body portion 23 of a pivot pin generally designated 24. The opposite ends 25 and 26 of the pivot pin are frustoconical narrowing outwardly and are received within openings 27 and 28 in the walls defined by brackets 20 and 21.

As shown in Figure 2, the wall 20 may be provided with an expandable sleeve 29 and the wall 21 may be provided with an expandable sleeve 30 coaxially re ceiving the pivot end portions 25 and 26 respectively. Means are provided for locking the pivot pin 24 effectively against movement relative to the walls 20 and 21 through the expandable sleeves 29 and 30 thereof. More specifically, the securing means generally designated 31 includes a first cup-shaped wedge member 32 embracing pivot pin end portion 25, and a second cup-shaped wedge member 33 embracing the opposite pivot end portion 26 within sleeves 29 and 30, respectively. As seen in Figure 2, the sidewall 34 of wedge member 32 defines a frustoconical inwardly widening inner surface 35 and the sidewall 36 of wedge member 33 defines a frustoconical inwardly widening inner surface 37 complementary to the frustoconical end portions 25 and 26 of the pivot pin. The wedging members 32 and 33 may be drawn forcibly inwardly to effect a wedging action between the pivot end portions 25 and 26 and the bracket walls 20 and 21 by a clamping means generally designated 38. More specifically, the clamping means may include a through rod 39 extending coaxially through pivot pin 24 and the bottom wall portions 40 and 41 of the wedge members 32 and 33, respectively.

End 42 of the rod is threaded and a nut 43 is threadedly secured thereto to engage the wedging means bottom wall 40. End 44 of the rod 39 is threaded and threadedly carries a nut 45 disposed to engage the bottom wall 41 of wedge member 33.

Thus, as seen in Firgure 2, threaded tightening of the nuts 43 and 45 urges the wedge members 32 and 33 axially inwardly against the frustoconical end portions 25 and 26 of the pivot pin thereby to expand the sleeve 30 radially outwardly and effectively lock the pivot pin to the bracket walls 20 and 21. In the illustrated embodiment, the sleeves 29 and 30 comprise split cylindrical sleeves having right circularly cylindrical inner surfaces engaged by correspondingly right circularly cylindrical outer surfaces of the wedge member sidewalls 34 and 35, respectively. It is preferable that light axial force be applied to the sleeves 29 and 30 during such securing operation and for this purpose, lubricant may be applied to the confronting surfaces of the sleeves and wedge members. The invention further comprehends the provision of improved sealing means generally designated 46 for retaining lubricant in the joint structure 18. As shown in Figure 3, the bushing portion 22 of the arm 11 may be provided with a recess 47 defining an oil lubricant reservoir. Lubricant may be delivered to the reservoir 47 through a suitable passage 48 in the arm 11. Sealing means 46 is arranged to retain the lubricant oil against leakage outwardly from the joint structure and thereby provide an improved long life, low maintenance joint construction. More specifically, sealing means 46 includes a thrust ring 58 coaxially mounted to the pivot pin body portion 23 as with a light press fit to effectively prevent rotation of the thrust ring or the pivot pin. If desired, the thrust ring may be pro vided with an annular radially inwardly opening recess 49 provided with an O-ring 50 to provide a static seal between the thrust ring and the pivot pin. Notwithstanding said dimensional tolerances in the manufacture of the joint structure, the thrust ring is ef fectively captured axially between an outer surface 51 of the bushing 22 and an inner surface 52 of the sleeve and is retained in axial abutment with these elements by the securing of the sleeve in this adjusted position by the wedge members. An annular seal generally designated 53 is provided having a radially inner portion 54 providing a dynamic seal with the outer surface 55 of the thrust ring 58. Seal ring 53 further includes an outer metallic ring portion 56 having a .static seal with an inwardly facing annular shoulder on the arm 11. The static seal may be effected by mounting the seal portion 56 in the annular shoulder 57 with a light press fit.

With reference to Figure 1, arm 11 may alternatively comprise the connecting rod 17, which, as illustrated in Figure 1, is pivotally connected between the wall members of arm 12. Thus, in referring to arm 11, as will be obvious to those skilled in the art, the description is equally pertinent to the pivot member 17. Referring now to the preferred embodiment of Figure 4, an improved joint structure generally designated 118 is shown to include a securing means 131 for locking the pivot pin 124 against rotative and axial movement and which is disposed at one end portion 125 only of the pivot pin. Thus, in the illustrated structure, securing means 131 includes a locking plate 159 which is secured to the beveled end surface 136 of the pivot pin by a suitable weld 160. The locking plate, in turn, is removably secured to the wall 120 by a bolt 161. As shown in Figure 4, the end of the pivot pin is flush with the outer surface of the wall and the inner surface of the locking plate 159.

The sealing means 146 is similar to sealing means 46 of the embodiment of Figures 1-3, and includes a seal ring 153 having a dynamic sealing engagement with the outer surface 155 of thrust ring 158. Sealing means 146 further includes a static seal defined by a seal ring 156 engaging the inner surface 157 of the arm 111. As indicated above, the pivotal member 111 may alternatively comprise the connecting rod 17 illustrated in Figure 1.

The thrust rings 158 are preferably press fitted to the body portion 123 of pivot pin 124. The fit may be a relatively light press fit but sufficient to effectively prevent rotation of the thrust ring on the pivot pin. As the pivot pin is effectively prevented from rotation and axial movement by the securing means 131, seal ring 154 has movable sealing engagement with the fixed surface 155 of the thrust ring as a result of pivotal movement of arm 11 of the pivotable arm.

Thus, the preferred embodiment 118 of the invention provides a simple low cost structure which yet functions similarly to the embodiment of Figures 2 and 3 in providing a positive, locked retention of the pivot pin by means removably secured to the wall means in which at least one end of the pivot pin is received. In the preferred embodiment of Figure 4, the securing means is effectively permanently secured to the end of the. pivot pin by means removably secured to the wall. In the embodiment of Figures 2 and 3, the end of the pin is removably secured to the wall through the expansible split sleeve.

Industrial Applicability

The improved joint structures 18 and 118 may be utilized in a wide range of industrial applications, the use thereof in the loader apparatus 10 being exemplary of such uses. The joint structures are advan tageously adapted for use in environments wherein hinge pins are utilized in environments where dirt and foreign matter may work its way under the seal as a result of endplay or the like in the hinge pins. The use of the joint structures provides a maintenance free extended life of the joint and permits the use of lubricant oil to provide improved lubrication thereof as compared to the prior art structures requiring the use of grease.

By providing the dynamic seal of the sealing means 46,146 on the ground-hardened surface of the thrust ring 58,158, an improved troublefree seal is provided.

By effectively maintaining the pivot pin against movement in the walls 20,120 and 21,121 and retaining the thrust rings in captured association against the arm bushing 22,122, further improved low maintenance, troublefree life of the joint structure is provided.

Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims. The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.

Claims

1. In a joint structure having a wall (20, 21;120,121) provided with an opening (27; 127) , and a pivot pin (24;124) having a body portion (23;123) coaxially within and pivotally carrying a pivot member (11; 111) , said pivot pin further having an end portion (25; 125) in said opening, the improvement comprising: a thrust ring (58; 158) fixedly sealed to said pin and extending coaxially between said wall and said pivot member; an annular seal (46; 146) having a first portion

(56; 156) statically sealed to said pivot member, and a second portion (54; 154) dynamically sealed to said thrust ring; and means (31; 131) for locking said pin end portion to said wall against axially and rotative movement relative to said wall.

2. In a joint structure having a wall (120, 121) provided with an opening (127) , and a pivot pin (124) having a body portion (123) coaxially within and pivotally carrying a pivot member (111) , said pivot pin further having an end portion in said opening, the improvement comprising: a thrust ring (158) fixedly sealed to said pin (124) and extending coaxially between said wall and said pivot member; an annular seal (146) having a first portion

(156) statically sealed to said pivot member, and a second portion (154) dynamically sealed to said thrust ring; locking structure (159,160) carried by said pin end portion; and means (161) for removably securing said locking structure to said wall for locking said pin end portion to said wall against axially and rotative movement relative to said wall.

3. In a joint structure (18) having a wall means (20,29 and 21,30) defining an opening, a pivot pin (24) having a body portion (23) coaxially within and pivotally carrying a pivot member (11) , and an end portion (25,26) in said opening, the improvement comprising: an annular wedge (32,33) in said opening coaxially about said pin end portion; a thrust ring (58) fixedly sealed to said pin and extending coaxially between said wall means (20,29 and 21,30) and said pivot member; an annular seal (46) having a first portion (56) statically sealed to said pivot member, and a second portion (54) dynamically sealed to said thrust ring; and means (38) urging said wedge axially inwardly to wedge between said pin end portion and wall means thereby to retain said sleeve in axial abutment with said thrust ring and said thrust ring in axial abutment with said pivot member and lock said pin end portion against axially and rotative movement relative to said wall means.

4. In a joint structure (18) having a wall

(20,21) provided with an opening (27,28), a pivot pin (24) having a body portion (23) coaxially within and pivotally carrying a pivot member (11) and an end portion (25,26) in said opening, the improvement comprising: an expandable sleeve (29,30) in said opening coaxially surrounding said pin end portion (25,26); an annular wedge (32,33) coaxially between said sleeve and said pin end portion; a thrust ring (58) fixedly sealed to said pin and extending coaxially between said sleeve and said pivot member; an annular seal (46) having a first portion (56) statically sealed to said pivot member, and a second portion (54) dynamically sealed to said thrust ring; and means (38) urging said wedge axially inwardly to wedge between said pin end portion and sleeve thereby to retain said sleeve in axial abutment with said thrust ring and said thrust ring in axial abutment with said pivot member and lock said pin end portion to said wall through said sleeve against axially and rotative movement relative to said wall.

5. The joint structure of Claims 1, 2, 3, or 4 wherein a static seal ring (50) is provided coaxially between said thrust ring and said pivot pin.

6. The joint structure of Claims 1, 2, 3, or 4 wherein said thrust ring (58) defines a radially outer annular sealing surface (55) and said seal second portion (54) sealingly engages said sealing surface.

7. The joint structure of Claims 1, 2, 3, or 4 wherein said pivot member (11) defines a radially inwardly facing sealing surface (57) and said seal first portion (56) sealingly engages said sealing surface.

8. The joint structure of Claims 1, 2, 3, or 4 wherein said pivot member (11) defines a radially inwardly facing sealing surface (57) and said seal first portion (56) comprises an annular metal element (56) press fitted to said sealing surface (57) to define the static seal of said annular seal (46) to said pivot member.

9. The joint structure of Claims 1, 2, 3, or 4 wherein said pivot member (11) includes an annular bushing (22) coaxially about said pin body portion (23).

10. The joint structure of Claims 1, 2, 3 or 4 wherein said pivot member (11) defines a passage (47,48) for delivering lubricating oil to between said pin (24) and said pivotable member (11) .

11. The joint structure of Claim 1 wherein the means (31; 131) for locking said pin to said wall includes a member (40; 159) cooperating with the pin end portion and said wall.

12. The joint structure of Claim 1 wherein the means (31) for locking said pin to said outer wall includes an expandable sleeve (29) in said opening (27) coaxially surrounding said pin end portion (25), an annular wedge (32) coaxially between said pin end portion, and means (39,42) urging said wedge axially inwardly to wedge between said pin end portion and sleeve in axial abutment with said pivot member.

13. The joint structure of Claim 2 wherein said locking structure comprises a locking plate (159) secured to said pivot pin end portion (125) .

14. The joint structure of Claim 2 wherein said locking structure comprises a locking plate (159) welded (160) to said pivot pin end portion (125) .

15. The joint structure of Claim 2 wherein said means for removably securing said locking structure to said wall comprises bolt means (161) .

16. The joint structure of Claim 2 wherein the end portion (125) of said pivot pin (124) is locked flush with said wall (120) .

17. The joint structure of Claim 3 wherein said pin (24) includes a portion (23) slip-fitted in said wall means.

18. The joint structure of Claim 3 wherein said pin (24) includes a portion (23) slip-fitted in said wall means and an axially outer portion (25,26) engaged by said wedge (32,33).

19. The joint structure of Claim 3 wherein said wedge (32,33) comprises a cup-shaped member having a bottom portion (40,41) adjustably secured to said pin end portion (25,26) .

20. In a joint structure (18) having first (20) and second (21) spaced walls each provided with an opening (27,28) , a pivot pin (24) havxng a body portion (23) coaxially within and pivotally carrying a pivot member (11) and first (25) and second (26) end portions received respectively one each in said openings (27,28) , the improvement comprising: a first expandable sleeve (29) in said first wall opening (27) coaxially surrounding the wall opening (27) coaxially surrounding the first pin end portion (25) therein; an annular first wedge (32) coaxially between said sleeve and said first pin end portion; a first thrust ring (58) fixedly sealed to said pin and extending coaxially between said sleeve and said pivotable member; a first annular seal (46) having a first portion (56) statically sealed to said pivot member (11) and a second portion (54) dy namically sealed to said thrust ring (58); a first urging means (39,43) for urging said wedge axially inwardly between said pin end portion and sleeve thereby to retain said sleeve in axial abutment with said thrust ring and said thrust ring in axial abutment with said pivotable member and lock said pin end portion to said wall through said sleeve against axially and rotative movement relative to said wall; a second expandable sleeve (30) in said second wall opening (28) coaxially surrounding said second pin end portion (26) ; a second annular wedge (33) coaxially between said second sleeve (20) and said second pin end portion (26) ; a second thrust ring (58) fixedly sealed to said pin and extending coaxially between said second sleeve (30) and said pivot member (11) ; a second annular seal (46) having a first portion (56) statically sealed to said pivot member (11) and a second portion (54) dynamically sealed to said second thrust ring (58); and means (39,45) urging said second wedge means (33) axially inwardly to wedge between said second pin end portion and second sleeve thereby to retain said sleeve in axial abutment with said thrust ring and said thrust ring in axial abutment with said pivot mem ber and lock said second pin end portion to said second wall through said second sleeve against axially and rotative movement relative to said second wall.

21. The joint structure of Claim 20 wherein said first and second urging means (43,45) comprise threaded means coaxially of the opposite pin end portions 42,44) .

22. The joint structure of Claim 20 wherein said urging means comprises a member (39) extending axially through said pivot pin (24) and means (43,45) at the opposite ends of said member adjustably engaging said wedges.

23. The joint structure of Claim 20 wherein each of said wedges comprises a cup-shaped element (32,33) adapted to receive the pin end portions (25, 26) therein.

24. The joint structure of Claim 20 wherein said pin end portions (25,26) define frustoconical outwardly tapering radial surfaces and said wedges (32,33) define complementary frustoconical surfaces.

25. The joint structure of Claim 20 wherein said sleeves comprise split cylindrical sleeves (29, 30) .

26. The joint structure of Claim 20 wherein said pivotable member (11) defines a passage (48,49) for delivering lubricating oil to between said pin body portion (23) and said pivot member (11) , said annular seal (46) being effective to retain lubricating oil therebetween.

27. The joint structure of Claim 20 wherein said pivot member (11) defines a radially inner bushing portion (22) coaxially mounted to said pin body portion (23) and defining an oil lubricant reservoir

(47).