Abstract:
A pivot joint mechanism for connecting together two relatively movable members which includes a pair of cone-type locks at the respective ends of a pivot pin which can be readily assembled and tightened to hold all of the internal parts locked in place by means of a single nut on a bolt extending through the pin, and which can be readily disassembled by inserting jack screws in the ends of the mechanism and backing the female locking members out again.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to pivot joint mechanisms for connecting together two relatively movable members which form a portion of a machine. It is particularly useful in earth moving machinery but is not limited to such use. 
     2. Description of the Prior Art 
     Numerous pivot joint mechanisms have been disclosed and used in or for earth moving machinery. One of the most troublesome uses of such a mechanism in earth moving machinery is that in which the mechanism pivotally connects a loader bucket to the outer end of a boom structure. Such mechanisms frequently operate under very adverse conditions including the presence of rocks, grit, dirt, water and other things which are found in material which is loaded or excavated by the earth moving machine. 
     SUMMARY OF THE INVENTION 
     The pivot joint mechanism of this invention employs a pair of cone-type locks at the respective ends of a pivot pin, which can be readily assembled to hold all of the internal parts in place. Each cone-type lock includes an inner male member and an outer female member, and both locks can be locked by means of a single bolt extending through a bore in the pin and a nut on such bolt. The pivot joint mechanism can be readily disassembled again by inserting jack screws in the female members at the ends of the mechanism and backing the female tapered locking members out again. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 of the drawing shows an axial sectional view, in section except for the pin, of a pivot joint mechanism according to the present invention; 
     FIG. 2 is a similar view of a pivot joint mechanism illustrating a second embodiment of the invention; and 
     FIG. 3 is a similar view of a pivot joint mechanism illustrating a third embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 of the drawing illustrates a pivot joint mechanism 10 in accordance with the present invention pivotally connecting two relatively movable members 12 and 14. Member 12 is bifurcated and includes two spaced apart plates 12a and 12b. The other member 14 is located, in part, between plates 12a and 12b. Each of said spaced plates 12a and 12b and member 14 has a circular opening therethrough, indicated by the numerals 16a, 18 and 16b respectively, with the centers of such openings aligned along an axis 20 extending transversely to planes coinciding with said movable members; as shown in FIG. 1 opening 18 is in a bushing 30 in member 14. 
     A cylindrical pivot pin 22, which is the principal structural member of the pivot joint mechanism, is located within openings 16a, 18 and 16b coaxially with axis 20, and is the member on which member 14 is journaled. The pivot pin 22 includes a central portion 24 and end portions 26 and 28 respectively. 
     In assembling a pivot mechanism in accordance with this invention a preliminary step is to assemble a sub-assembly 31. Such sub-assembly which includes bushing 30 and related parts in done apart from the location shown in the patent drawing. In making sub-assembly 31 a bearing seal retainer 36 is put in place in opening 18 through bushing 30 and secured to bushing 30 in a suitable manner such as by welding at 38. Then an anti-friction bearing, such as a tapered roller bearing 39, is put in place abutting bearing seal retainer 36. Then a spacer 33 is put in place after which a second tapered roller bearing 41 is put in place with the outer race 41a thereof abutting spacer 33. Then a second seal retainer 40 is put in place and is secured to bushing 30 as by welding 42. The two seal retainers abut the outer races 39a 41a of the bearings and are provided with seals 44 and 46 respectively to retain lubricant within bearing sub-assembly 31. 
     Next the sub-assembly 31 is assembled, preferably with a press fit, in mating opening 32 in member 14, and sub-assembly 31 and member 14 may be further secured together by a bolt (not shown) extending through opening 34. After the foregoing sub-assembly is put in place a pair of spacer rings 48 and 50 including seals 52 and 54 respectively are added. Next two annular male locking cones 56 and 58 are put in place abutting spacers 48 and 50 respectively. Then mating female locking cone members 60 and 62 are put in place so that the inner frustro-conical surface of cone members 60 and 62 are in contact with the outer frustro-conical surfaces of male members 56 and 58 respectively. Each of said female members includes an integral end closure portion, 60a and 62a respectively, which may be secured to the annular portions of said female members by welding. 
     Pin 28 has an axial bore 68 therethrough and in the assemble condition the pivot joint mechanism includes a bolt 70 extending through said bore. Portions 60a and 62a of the female locking cone members have threaded openings 76 and 78 respectively which are of larger diameter than bore 68. After all the parts of the pivot mechanism have been assembled as described hereinbefore bolt 70 is then passed through bore 68 and nut 80 is tightened on the other end to urge the female cone members against the surfaces of the male cone members and against the surrounding surfaces 16a and 16b respectively in order to lock and hold the pivot joint mechanism in place during operation. 
     When it is desired to disassemble the pivot mechanism again it is necessary only to remove nut 80 and then remove bolt 70. Then, a jack screw is screwed into mating internal threads in opening 76 until it abuts the outer end 82 of the pin. When said jack screw is turned further the female cone member becomes disengaged from the mating male cone member and the surrounding surface of member 12. After the female cone member at the other end is handled similarly by a jack screw in opening 78 the mechanism can be completely disassembled by removing spacers 48 and 50 and then removing sub-assembly 31 from bushing 30. 
     FIG. 2 of the drawing illustrates a second embodiment of the invention wherein bushing member 30 is omitted and member 14a, corresponding to 14 of the first embodiment, has an opening 19 therethrough which may be of the same diameter as opening 18 through the bushing 30 of the first embodiment. Both bearing seal retainers 36 and 40, bearings 39 and 41, and spacer 33 are assembled in member 14a in the same manner as the same parts were installed in bushing 30 in the first embodiment. Then all remaining parts are assembled in the same manner as in the first embodiment. 
     FIG. 3 of the drawing illustrates a third embodiment of the invention wherein a single pair of annular face seals 45 and 47 replaces the two pairs of seals 44,46 and 52,54 of the other two embodiments. In FIG. 3 parts which are the same or essentially the same as in FIG. 1 have the same identifying numerals. The third embodiment has one bearing spacer not found in the other two embodiments, namely, spacer 35 which is located between the inner races 39b and 41b respectively of the anti-friction bearings. In the third embodiment there are no seals 52 and 54, and as a consequence the affected spacer rings in FIG. 3 are indicated by the numerals 48a and 50a. Seals 45 and 47 are located respectively in sealing contact in a pair of annular recesses 36a and 40a in retainers 36 and 40. The seals are made functionally complete by sealing contact between seal members 45 and 47 respectively and annular seal brackets 81 and 82 on male members 56 and 58 respectively. 
     The pivot joint mechanism of this invention gives extended bearing lubrication intervals and absorbs thrust loads through the anti-friction bearings. It also eliminates the necessity of shims, eliminates welding to the pin and the use of lock plates. It allows assembly of the invention structure without damage to the seals. 
     While we have described and illustrated herein preferred embodiments of our invention, illustrating in the first embodiment the best mode contemplated for carrying out the invention, it will be understood by those skilled in the art that modifications may be made. For example, it will be appreciated that a single anti-friction bearing may be used in some pivot joints instead of two as disclosed herein. We intend to cover by the appended claims all such modifications which fall within the true spirit and scope of our invention.