TAME OMAR D (US)
| US4746239A | 1988-05-24 | |||
| US3561792A | 1971-02-09 | |||
| US5697141A | 1997-12-16 | |||
| US6751841B2 | 2004-06-22 |
What is claimed:
1. A pivot j oint comprising:
a first member including an opening surrounded by a conical flange;
a second member including an opening surrounded by a conical flange, wherein said conical flange of one of said first and second members is nested within said conical flange of the other of said first and second members thereby pivotally coupling said first and second members together and defining bearing surfaces between said conical flanges; and
a pivot pin including an enlarged head and an elongated shank, said enlarged head disposed adjacent said conical flange of one of said first and second members and said elongated shank extending through said openings in said first and second members for pivotally retaining said first and second members together.
2. A pivot joint as set forth in claim 1 including a biasing member disposed between said head of said pivot pin and said conical flange of one of said first and second members for biasing said conical flange of said first member against said conical flange of said second member.
3. A pivot joint as set forth in claim 2 wherein said biasing member is a wave washer having an axial opening through which said shank of said pivot pin extends, said wave washer disposed between said head of said pivot pin and said conical flange of one of said first and second members for biasing said first and second members together.
4. A pivot joint as set forth in claim 3 wherein said conical flange of one of said first and second members nests within said conical flange of the other of said first and second members such that a gap is formed between said first and second members.
5. A pivot joint as set forth in claim 4 wherein said wave washer bows outwardly away from said conical flange of the one of said first and second members thereby creating a biasing force to bias said conical flange of one of said first and second members against said conical flange of the other of said first and second members.
6. A pivot joint as set forth in claim 5 wherein a wall thickness of said conical flange of said first member is greater than a wall thickness of said conical flange of said second link.
7. A pivot joint as set forth in claim 6 wherein said conical flange of said second member is nested within said conical flange of said first member.
8. A pivot joint as set forth in claim 7 wherein said wall thickness of said conical flange of said first member is less than a wall thickness of said first member and said wall thickness of said conical flange of said second member is less than a wall thickness of said second member.
9. A pivot joint as set forth in claim 8 wherein a distal end of said elongated shank is deformed to pivotally retain said first and second members together.
10. A pivot joint as set forth in claim 8 wherein a distal end of said elongated shank includes a bead of weld disposed therearound to pivotally retain said first and second members together.
11. A pivot joint as set forth in claim 8 wherein a distal end of said elongated shank includes a ring disposed therearound to pivotally retain said first and second members together.
12. A pivot joint as set forth in claim 11 wherein said distal end of said elongated shank is deformed.
13. A pivot joint as set forth in claim 8 wherein said elongated shank is at least semi-tubular and a distal end of said semi-tubular shank is deformed to pivotally retain said first and second members together.
14. A method of manufacturing a pivot joint including a first member, a second member, and a pivot pin having an enlarged head and an elongated shank extending therefrom defining a distal end, the method comprising the steps of: piercing a hole in the first member;
extruding material around the hole in the first member to form an opening and a conical flange surrounding the opening;
piercing a hole in the second member;
extruding material around the hole in the second member to form an opening and a conical flange surrounding the opening;
aligning the openings in the first and second members with the conical flanges protruding in a common direction;
coupling the first and second members by nesting the conical flange of one of the first and second members within the conical flange of the other of the first and second members;
inserting the shank of the pivot pin through the openings in the first and second members such that the head is adjacent the conical flange of one of the first and second members; and
manipulating the distal end of the shank to pivotally retain the first and second members together.
15. A method as set forth in claim 14 wherein the step of manipulating the distal end of the shank includes deforming the distal end of the shank.
16. A method as set forth in claim 14 wherein the step of manipulating the distal end of the shank includes securing the distal end of the shank to one of the first and second members.
17. A method as set forth in claim 14 wherein the step of manipulating the distal end of the shank includes disposing a ring therearound and deforming the distal end of the shank.
18. A method of manufacturing a pivot joint including a first member, a second member, a pivot pin having an enlarged head and an elongated shank extending therefrom defining a distal end, and a wave washer having an axial opening, the method comprising the steps of:
piercing a hole in the first member;
extruding material around the hole in the first member to form an opening and a conical flange surrounding the opening;
piercing a hole in the second member;
extruding material around the hole in the second member to form an opening and a conical flange surrounding the opening;
aligning the openings in the first and second members with the conical flanges protruding in a common direction;
coupling the first and second members by nesting the conical flange of one of the first and second members within the conical flange of the other of the first and second members;
inserting the shank of the pivot pin through the axial opening in the wave washer and the openings in the first and second members such that the head is adjacent the conical flange of one of the first and second members; and
manipulating the distal end of the shank to pivotally retain the first and second members together. |
Conic Flange Pivot Joint
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and all the benefits of United States
Provisional Application No. 61/024,258, filed on January 29, 2008 and entitled "Wave Washer Pivot Joint."
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to pivot joints, and more particularly, to a pivot joint having relatively large bearing surfaces for improved wear of the pivot joint over time.
2. Description of Related Art
[0003] Pivotal connections between two members or links are common, particularly in seat assemblies for automotive vehicles which typically have a plurality of pivotal connections between pairs of links. One of the most common types of pivotal connections is formed using a conventional rivet or pivot pin to pivotally connect a pair of links. The pivot pin has a preformed first head and a malleable tubular body or shank extending through cylindrical openings in the links. The distal end of the malleable body is compressed to form a second head, pivotally connecting the links between the first and second heads of the rivet.
[0004] An example of another type of pivotal connection is shown in United States
Patent No. 2,556,449 to Scheeler. The pivotal connection in Scheeler discloses a pivot pin having a shank with two cylindrical sections. A first cylindrical section of the shank, adjacent the first head is provided with a larger diameter which fits into a larger cylindrical opening in a first link. A second cylindrical section of the shank is provided with a reduced diameter which fits into a smaller cylindrical opening in a second link. An annular offset around the relatively large opening in the first link is offset toward the second link. This annular offset ensures adequate spacing between the first and second links so as to avoid scraping of their opposing faces. The shank of the pivot pin is inserted through the first link
and the first cylindrical section is proportioned to extend to the extremity of the annular offset. After the shank has been inserted through the first and second links, the second cylindrical section is welded or staked to the second link to pivotally connect the first and second links together.
[0005] Another example of a common pivotal connection is shown in U.S. Patent No.
5,015,136 to Vetter et al. The pivotal connection in Vetter et al. discloses a pivot pin wherein a shank has two sections defining a shoulder therebetween. A first section of the shank, adjacent a first head, has a diameter greater than a second section and its length is slightly greater than a first link is thick. The shoulder abuts a second link to prevent the second link from being frictionally bound against the first link during formation of a second head. Such binding is undesirable because it restricts free pivoting of the links during operation.
[0006] Each of the previously described pivotal connections include bearing surfaces that are defined as the contact surfaces between the shank of the pivot pin and the opening in the link or links that pivot. The size of the bearing surfaces are limited by the thickness of the links and are typically quite small. Thus, loads carried by the pivotal connection during use are concentrated on the small bearing surfaces and over a period of extended use, the pivotal connection will wear causing the openings in the links to enlarge which leads to looseness in the pivotal connection. In addition, wear of the pivot pin and links can lead to undesirable axial free play between the links. Such free play can cause excessive wear on the links and the components connected to the links. Too much axial free play can also lead to jamming of the mechanism at the pivotal connection.
[0007] It is therefore desirable to provide a pivot joint for pivotally connecting a pair of members or links, wherein the pivot joint has relatively large bearing surfaces for improved wear over time. It is also desirable to provide a pivot joint having a wave washer for pre-loading a pair of members or links and minimizing axial free play as the pivot joint wears over time.
SUMMARY OF THE INVENTION
[0008] According to one aspect of the invention, a pivot joint is provided for pivotally connecting a first member and a second member. The first member includes an opening surrounded by a conical flange. The second member includes an opening surrounded by a conical flange. The conical flange of the second member is nested within the conical flange of the first member thereby pivotally coupling the first and second members together and defining bearing surfaces between the conical flanges. A pivot pin includes an enlarged head and an elongated shank. The head is disposed adjacent the conical flange of the first member. The elongated shank extends through the openings in the first and second members to pivotally retain the first and second members together.
[0009] According to another aspect of the invention, there is provided a method of manufacturing a pivot joint including a first member, a second member, and a pivot pin having an enlarged head and an elongated shank extending therefrom defining a distal end. The method of manufacturing the pivot joint comprises the steps of: piercing a hole in the first member; extruding material around the hole in the first member to form an opening and a conical flange surrounding the opening; piercing a hole in the second member; extruding material around the hole in the second member to form an opening and a conical flange surrounding the opening; aligning the openings in the first and second members with the conical flanges protruding in a common direction; coupling the first and second members by nesting the conical flange of the second member within the conical flange of the first member; inserting the shank of the pivot pin through the openings in the first and second links such that the head is adjacent the conical flange of the first member; and manipulating the distal end of the shank to pivotally retain the first and second members together.
[0010] According to yet another aspect of the invention, a wave washer is disposed between the head of the pivot pin and the conical flange of the first member for biasing the conical flange of the first member against the conical flange of the second member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
[0012] Figure 1 is a cross-sectional side view of a first pivot joint from the prior art;
[0013] Figure 2 is a cross-sectional side view of a second pivot joint from the prior art;
[0014] Figure 3 is a cross-sectional side view of a pivot joint according to one embodiment of the invention;
[0015] Figure 4a is a perspective view illustrating first and second links to be pi vo tally connected to form the pivot joint;
[0016] Figure 4b is a perspective view illustrating the first and second links having pilot holes formed therethrough;
[0017] Figure 4c is a perspective, cross-sectional view illustrating a first tool forming a first conical flange in the first link and a second tool forming a second conical flange in the second link;
[0018] Figure 4d is a partially exploded, cross-sectional perspective view illustrating the first and second conical flanges nested together;
[0019] Figure 4e is a perspective, cross-sectional view illustrating an assembled pivot joint;
[0020] Figure 5 is a cross-sectional side view of a pivot joint according to a second embodiment of the invention;
[0021] Figure 6 is a cross-sectional side view of a pivot joint according to a third embodiment of the invention; and
[0022] Figure 7 is a cross-sectional side view of a pivot joint according to a fourth embodiment of the invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0023] One type of prior art pivotal connection or pivot joint 10 (such as was referred to generally in the above Description of Related Art section) between a first link 12 and a second link 14 is generally shown in Figure 1. The first link 12 includes a cylindrical opening 16 therethrough and the second link 14 includes a cylindrical opening 18 therethrough. A rivet or pivot pin 20 extends through the opening 16 in the first link 12 and through the opening 18 in the second link 14 to pivotally interconnect the first 12 and second 14 links. The pivot pin 20 has an enlarged head 22 with a link engaging surface 24 and an elongated shank 26 extending therefrom. The link engaging surface 24 abuts an outer surface 28 of the first link 12 and a distal end 30 of the shank 26 is welded or staked at an outer surface 32 of the second link 14, thereby pivotally connecting the first 12 and second 14 links together, hi the embodiment shown, the second link 14 may be fixed such that pivoting occurs between the first link 12 and the pivot pin 20. Therefore, the surface of the opening 16 in the first link 12 and the shank 26 of the pivot pin 20 define bearing surfaces 34, 35. It is appreciated that the bearing surfaces 34, 35 are relatively small, and over a period of extended use wear will cause the opening 16 in the first link 12 to enlarge, which leads to excessive looseness and sloppiness in the pivot joint 10, and ultimately to failure. In addition, it is appreciated that with the straight pivot pin 20 pivotally connecting the first 12 and second 14 links it is almost impossible to manufacture a series of pivot joints without some being excessively loose and others causing binding between the first 12 and second 14 links.
[0024] A second type of prior art pivot joint 100 (such as was also referred to generally in the above Description of Related Art section) between a first link 112 and a second link 114 is generally shown in Figure 2. The first link 112 includes a cylindrical opening 116 therethrough and the second link 114 includes a cylindrical opening 118
therethrough. The opening 116 in the first link 112 is larger than the opening 118 in the second link 114. A stepped pivot pin 120 extends through the opening 116 in the first link 112 and through the opening 118 in the second link 114 to pivotally interconnect the first 112 and second 114 links. The pivot pin 120 has a first enlarged head 122 with a link engaging surface 124 and an elongated shank 126 extending therefrom. The link engaging surface 124 abuts an outer surface 128 of the first link 112 and a distal end of the shank 126 is deformed to form a second enlarged head 130 abutting an outer surface 132 of the second link 114, thereby pivotally connecting the first 112 and second 114 links together. The shank 126 includes a first portion 136 and a second portion 138 defining a shoulder 140 therebetween. The first portion 136 of the shank 126 fits within the opening 116 in the first link 112. The first portion 136 of the shank 126 has a diameter larger than the opening 118 in the second link 114 and an axial length that is slightly greater than the first link 112 is thick so that the second link 114 abuts the shoulder 140 rather than the first link 112. Preferably, the first portion 136 of the shank 126 and the opening 116 in the first link 112 are cylindrical to permit pivoting between the pivot pin 120 and the first link 112. As such, the surface of the opening 116 in the first link 112 and the first portion 136 of the shank 126 of the pivot pin 120 define bearing surfaces 134, 135. As is understood by those skilled in the art, the shoulder 140 engages the second link 114 to prevent compression of the pivot pin 120 that would otherwise result in binding of the first 112 and second 114 links. While this type of stepped pivot pin prevents the above described binding of the first 112 and second 114 links, it may result in undesirable axial free play in the pivot joint 100. Specifically, due to tolerances required in the manufacture of the first link 112 and the pivot pin 120 (particularly the first enlarged head 122 and the first portion 136 of the shank 126), and particularly inasmuch as these tolerances should ensure even at one extreme that the first 112 and second 114 links will not bind when assembled, the assembled pivot joint 100 naturally has some undesirable axial spacing, indicated by 142, allowing some undesirable free play in the pivot joint 100.
[0025] Referring to Figures 3 and 4a through 4e, a pivot joint of the present invention is generally shown at 200. The pivot joint 200 reduces wear and, at the same time, virtually eliminates undesirable axial free play. The pivot joint 200 of the present invention was
particularly designed for use as a simple pivot joint for pivotally connecting members or links of a vehicle seat assembly. It is appreciated, however, that the pivot joint 200 may be used for pivotally connecting any of a variety of members without varying from the scope of the invention.
[0026] The pivot joint 200 includes a first link 212 and a second link 214. The first link 212 includes a cylindrical opening 216 extending therethrough and a conical flange 217 surrounding the opening 216. The conical flange 217 protrudes axially from the first link 212. Similarly, the second link 214 includes a cylindrical opening 218 extending therethrough and a conical flange 219 surrounding the opening 218. The conical flange 219 protrudes axially from the second link 214. It is appreciated that a method of forming the conical flange 217 of the first link 212 and the conical flange 219 of the second link 214, described below in further detail, results in a wall thickness Tl, T2 of the respective conical flanges 217, 219 that is less than a wall thickness T3, T4 of the respective first 212 and second 214 links, as shown in Figure 4c.
[0027] The conical flange 219 of the second link 214 is sized to nest within the conical flange 217 of the first link 212 such that the first 212 and second 214 links are pivotally connected together, as shown in Figure 3. In the embodiment shown, the wall thickness Tl of the conical flange 217 of the first link 212 is greater than the wall thickness T2 of the conical flange 219 of the second link 214 such that the conical flange 219 of the second link 214 can nest within the conical flange 217 of the first link 212. The nesting of the conical flange 219 of the second link 214 within the conical flange 217 of the first link 212 creates a gap 231 between the first 212 and second 214 links. The gap 231 encourages free pivoting between the first 212 and second 214 links, hi addition, the conical flange 217 of the first link 212 and the conical flange 219 of the second link 214 define first 234 and second 235 bearing surfaces. More specifically, the inner surface of the conical flange 217 of the first link 212 defines the first bearing surface 234 and the outer surface of the conical flange 219 of the second link 214 defines the second bearing surface 235. It is appreciated that the first 234 and second 235 bearing surfaces are relatively large compared to the bearing surfaces 34, 35 and 134, 135 of the respective prior art pivot joints 10 and 100. The
large first 234 and second 235 bearing surfaces improve the wear characteristics of the pivot joint 200 of the present invention over that of the respective pivot joints 10, 100 of the prior art.
[0028] The first 212 and second 214 links are retained together by a rivet or pivot pin
220 extending through the openings 216, 218 in the respective first 212 and second 214 links. More specifically, the pivot pin 220 includes an enlarged head 222 having a contact surface 224 and an elongated shank 226 extending therefrom. The head 222 of the pivot pin 220 is disposed adjacent the conical flange 217 of the first link 212 and the shank 226 extends through the opening 216 in the first link 212 and through the opening 218 in the second link 214. A distal end 230 of the shank 226 is staked to pivotally retain the first 212 and second 214 links together. Staking enlarges the distal end 230 of the shank 226, as shown in Figure 3, such that the pivot pin 220 cannot be pulled back out of the openings 216, 218.
[0029] Alternatively, the distal end 230 of the shank 226 may be fixedly secured to the second link 214 by a bead of weld 239, as shown in Figure 5, or an equivalent means of connection in order to pivotally retain the first 212 and second 214 links together. It is also contemplated that a ring or washer 241 may be disposed about the distal end 230 of the shank 226 such that only a small amount of staking is required to retain the washer 236 thereon, as shown in Figure 6. The washer 236 in turn pivotally retains the first 212 and second 214 links together. It is further contemplated that the pivot pin 220 may have a tubular or semi- tubular shank 243, shown in Figure 7, which decreases the amount of staking force required.
[0030] A wave washer 244 is disposed between the contact surface 224 of the head
222 of the pivot pin 220 and a distal end 246 of the conical flange 217 of the first link 212 for biasing the first 212 and second 214 links together. The wave washer 244 includes an axial opening 248 through which the shank 226 of the pivot pin 220 extends. The wave washer 244 is bowed outwardly away from the distal end 246 of the first link 212 thereby creating an axial biasing force that pre-loads or biases the conical flange 217 of the first link 212 against the conical flange 219 of the second link 214. The wave washer 244 provides axial compliance such that the first link 212 can move axially relative to the second link 214 during operation of the pivot joint 200. As the pivot joint 200 wears over time, the biasing
force of the wave washer 244 continues to urge the conical flange 217 of the first link 212 against the conical flange 219 of the second link 214, thereby preventing undesirable axial free play between the first 212 and second 214 links. It is contemplated that other types of biasing members could be used in place of the wave washer 244 for biasing the conical flange 217 of the first link 212 against the conical flange 219 of the second link 214 without varying from the scope of the invention.
[0031] The pivot joint 200 of the present invention is manufactured according to the following steps, which are illustrated in the accompanying Figures 4a through 7. In a first step, a first pilot hole 250 is pierced through the first link 212, as shown in Figures 4a and 4b. The first pilot hole 250 is smaller in diameter than the cylindrical opening 216 in the first link 212. hi a second step, material around the first pilot hole 250 is extruded using a tool 252 to form the opening 216 in the first link 212 and the conical flange 217 surrounding the opening 216 in the first link 212, as shown in Figure 4c. hi a third step, a second pilot hole 254 is pierced through the second link 214, as shown in Figures 4a and 4b. The second pilot hole 254 is smaller in diameter than the cylindrical opening 218 in the second link 214. hi a fourth step, material around the second pilot hole 254 is extruded using a tool 256 to form the opening 218 in the second link 214 and the conical flange 219 surrounding the opening 218 in the second link 214, as shown in Figure 4c. hi a fifth step, the opening 218 in the second link 214 is axially aligned with the opening 216 in the first link 212 with the respective conical flanges 217, 219 protruding in a common direction, hi a sixth step, the first 212 and second 214 links are pivo tally connected together by nesting the conical flange 219 of the second link 214 within the conical flange 217 of the first link 212, as shown in Figure 4d. Alternatively, it is contemplated that the first 212 and second 214 links may be pivotally connected together by nesting the conical flange 217 of the first link 212 within the conical flange 219 of the second link 214, without varying from the scope of the invention. In a seventh step, the shank 226 of the pivot pin 220 is inserted through the axial opening 248 of the wave washer 244, through the opening 216 in the first link 212, and through the opening 218 in the second link 214 such that the head 222 is adjacent the conical flange 217 of the first link 212, as shown in Figure 4e. The wave washer 244 is slightly compressed between the contact surface 224 of the head 222 of the pivot pin 220 and the distal end 246 of the
conical flange 217 of the first link 212. In an eighth step, the distal end 220 of the shank 226 is manipulated in such a way that the first 212 and second 214 links are retained together, as shown in Figure 4e. In Figure 5, the bead of weld 239 is disposed around the distal end 230 of the shank 226. hi Figure 6, the washer 241 is disposed about the distal end 230 of the shank 226 and the distal end 230 is then staked to retain the washer 241. In Figure 7, the distal end 230 of the semi-tubular shank 243 is staked.
[0032] The invention has been described here in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of words of description rather than limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically enumerated within the description.