Arrangement and method for connecting a rod end to a headed pin

Abstract

A connection for a rod and pin includes a two piece housing molded from hard plastic which defining a cavity enclosing a soft elastomeric isolator on one end of the rod. The housing pieces also define a pin receiving cavity with retention prongs which engage and hold a pin inserted therein. The housing pieces are able to be snap fit assembled by interfitting prongs and receptacles formed on each housing piece. The housing pieces are molded together as one part, connected by an integral hinge allowing the housing parts to be swung into abutment with each other to be snap fit together.

Description

BACKGROUND OF THE INVENTION

[0002] This invention concerns mechanical connections between control rod ends and a pivot pin, as are commonly used to connect control rods to a pin in transmission linkages for automobiles.

[0003] In these connections, it is now usual to incorporate a soft elastomeric isolator between the rod and the pin to minimize the transmission of vibrations to a shift lever for example which is gripped by the hand of the driver of an automobile. A disadvantage of such isolators has been the looseness or lash introduced into the connection by the pin contact compressing the isolator material.

[0004] Such looseness has also been introduced by the clearances necessary to assemble the component parts of the connection.

[0005] Labor costs are also incurred by the need to fit together complex components to complete the connection when the automobile is assembled, and the need to insure proper assembly.

[0006] Another difficulty has been involved in attempting to reduce the force necessary to fit the pin to the connection to simplify assembly while still insuring that an adequately high separation force would be required to disconnect the pin after the connection is made to prevent unintended disconnection.

[0007] It is the object of the present invention to provide an arrangement and method for connecting one end of a rod to a headed pin which incorporates a vibration isolator without introducing excessive looseness in the connection.

[0008] It is another object of the present invention to provide such an arrangement and method in which there are minimal clearances necessary for assembly purposes.

[0009] It is yet another object of the present invention to provide such an arrangement and method which requires only low installation forces while insuring that separation forces are sufficiently high to preclude unintended disconnection of the components.

SUMMARY OF THE INVENTION

[0010] The above recited objects and other objects which will become apparent upon a reading of the following specification and claims are achieved by an arrangement and method for connecting a rod end to a headed pin, the arrangement including a housing defining a pin receiving cavity with integral retention features in the cavity engaging the headed pin so as to be retained therein. A soft elastomeric isolator is interposed between portions of the housing and the one end of the rod. The housing is formed by assembling two housing pieces together so as to enclose the vibration isolator and the one end of the rod. Both housing pieces are preferably molded as a single part from a hard plastic, with a connecting integral hinge allowing the pieces to be swung together to bring complementary faces into abutment with each other.

[0011] Molded contact prongs project inwardly from a recess portion of each housing piece, the recess of each housing piece together defining a pin receiving cavity. The contact prongs engage the underside of a head on the pin to capture the same when the assembled housing is pushed onto the pin.

[0012] The contact prongs are shaped to be easily deflected by contact with a head on the pin to allow entry of the pin but to thereafter strongly resist pull out of the pin to provide a secure connection.

[0013] The housing pieces are also formed with semicircular recesses which together form a generally cylindrical ribbed cavity which captures the isolator when the housing pieces are assembled together. Engaging features comprised of assembly prongs project from each abutting housing piece face, and are each received in a corresponding receptacle on the opposite piece face to fix the two housing pieces together. The isolator is comprised of a soft elastomeric material which is itself assembled or molded to a ribbed rod end to be secured thereto.

[0014] The isolator has relatively thin thicknesses subject to compression to limit movement thereof as a result of its compression while preventing the transmission of vibrations from the rod end to the hard plastic housing and metal pin. An interference fit between the isolator and the portions of housing pieces moved into engagement with the isolator when the housing pieces are assembled together insures that no looseness or lash will be created at assembly as with previous designs, while not requiring an overmolding process.

[0015] An orientation feature is molded integrally with the housing pieces preventing assembly to the pin in the wrong orientation to further simplify making of the rod end connection.

DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a top perspective view of a rod-pin connection housing constructed according to the invention and assembled to an isolator and rod end.

[0017] FIG. 2 is a perspective view from a steeper angle of the connection components shown in FIG. 1.

[0018] FIG. 3 is a perspective view of the two housing pieces prior to being swung towards each other with the rod end and isolator received in a recess of one of the housing pieces.

[0019] FIG. 4 is a perspective view of the two housing pieces partially swung together with the rod end and isolator in position in the recess of one of the two housing pieces.

[0020] FIG. 5 is a perspective view from one side of one of the two housing pieces positioned on a headed pin and receiving the rod end and isolator.

[0021] FIG. 6 is a front view of the two housing pieces as molded connected together, shown in a spread apart position.

[0022] FIG. 7 is a top view of a contact prong portion of one of the two housing pieces.

[0023] FIG. 8 is a view of the section 8-8 taken in FIG. 7.

[0024] FIG. 9 is a view of the section 9-9 taken in FIG. 7.

[0025] FIG. 10 is an enlarged view of a rod end with a sectional view of an isolator disposed thereon.

DETAILED DESCRIPTION

[0026] In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims.

[0027] Referring to the drawings, FIGS. 1 and 2 show a rod end connection housing 10, comprised of two housing pieces 12A, 12B assembled together with complementary faces 34A, 34B (FIGS. 3, 4) thereof in abutment with each other and capturing a steel rod end 14 and isolator 16.

[0028] FIGS. 3, 4 and 6 show the housing pieces 12A, 12B separated prior to being assembled together.

[0029] Both housing pieces 12A, 12B are molded as one part, in an end-to-end relationship connected by an integral hinge 18. The housing pieces 12A, 12B are identical except for the reversal of locations of a series of assembly prongs 20 and mating prong receptacles 22.

[0030] The housing pieces 12A, 12B are molded from a hard plastic such as Dow Vydne™ (Nylon 66%, graphite filled 33%), Rockwell hardness scale M95 (ASTM D785) or similar materials so as to not be readily compressed by contact pressure exerted by the pin 24 (FIG. 5) to which it is to be assembled.

[0031] Each housing piece 12A, 12B is molded with a main portion 26A, 26B having a semicircular recess 28A, 28B which together form a generally cylindrical pin receiving opening when the housing pieces 12A, 12B are assembled together.

[0032] Similarly, generally semicircular ribbed recesses 30A, 30B are molded into end portions 32A, 32B.

[0033] Barbed assembly prongs 20 project normally from respective abutment faces 34A, 34B of each housing piece 12, 12B, and are captured when inserted into complementary receptacles 22 by suitable ridges 21 formed in each receptacle capturing the barbed end of each prong 20 when inserted therein as the housing pieces 12A, 12B are swung together.

[0034] Each housing piece 12A, 12B is formed with a contact prong 36A, 36B extending parallel to the pin receiving recess 28A, 28B.

[0035] As shown in FIGS. 7-10, a lip portion 38 thereof is formed at an upper end of each contact prong 36A, 36B, having a sloping surface at the bottom adjacent the entry and of recess 28A and a relative blunt top surface 42 at the end of each contact prong 36A, 36B.

[0036] A clearance space 42 allows limited outward deflection during pin insertion until contact of a rib 44 with the outer wall defining recess 28A, 28B.

[0037] The sloping lip surface 40 of each contact prong 36A, 36B allows insertion of the pin 24 by radial deflection of the contact prong 36A, 36B while the pressure on the blunt top surfaces 42 is strongly resisted to prevent withdrawal and thus to provide high separation forces. These forces can be designed for by selection of the configuration of each contact prong 36A, 36B.

[0038] The housing pieces 12A, 12B are also each integrally formed with a pin blocking orientation 21A, 21B respectively which extend over one end of the recesses 28A, 28B which block entry of the pin 24 from the wrong side.

[0039] The isolator 16 is molded from a soft elastomer such as the following thermoplastic polyester elastomers:

[0040] Dupont Hytrel™ 5526,

[0041] Bayer Desmopan™ 453, Shore hardness 53D (ASTM D2240)

[0042] Dupont Hytrel™ 4069

[0043] Bayer Texin 285

[0044] Bayer Texin 270

[0045] Bayer Desmopan™ 460

[0046] Novi Estane 58133 (formerly BF Goodrich).

[0047] The isolator 16 is preferably molded onto the steel rod end 14 as shown in FIGS. 3 and 10, although it could be separately molded and assembled thereto, which is formed with a wide groove 42 into which the material of the isolator 16 extends. The isolator 16 is itself formed with an intermediate groove 45 into which a land 46A, 46B on each housing piece end portion 32A, 32B extends to create a secure interlock. A land 48A, 48B of each end portion 32A, 32B also projects over a shoulder 50 of the isolator 16 to further strengthen the connection.

[0048] As shown in FIGS. 4 and 5, the isolator 16 completely encloses the rod end 14 to prevent any direct contact with the housing pieces 12A, 12B, but the sections which are subjected to compression during service are relatively thin, i.e., 1 mm or less. Also, there is an absence of any points of concentrated compressive stress as occurred when a headed pin was made to bear on a soft elastomeric isolator, such that excessive lash is avoided.

Claims

1. An arrangement for connecting one end of a rod to a headed pin to enable driving engagement of said pin with said rod including: a housing defining a pin receiving cavity with retention features around said cavity engaging said headed pin so as to be retained therein; a soft elastomeric isolator interposed between said housing and said one end of said rod; said housing comprised of two pieces fit together and configured to enclose said vibration isolator and also said one end of said rod, said two pieces fixed together in assembling said housing.

2. The arrangement according to claim 1 wherein said housing pieces are fixed together by snap fit prongs on one housing piece received in receptacles on the other housing piece.

3. The arrangement according to claim 2 wherein said housing pieces are molded as one part, said housing pieces connected together with an integral hinge allowing said housing pieces to be swung together into abutment with each other and fit over said isolator.

4. The arrangement according to claim 3 wherein said housing pieces each have a recess defined therein said recesses together forming a cavity when said housing pieces are assembled abutting each other enclosing said isolator.

5. The arrangement according to claim 4 wherein one end of said rod has a groove formed therein, and said isolator has a portion fit into said groove, said isolator having a groove formed therein, and said housing pieces each having a portion fit into said isolator groove when assembled together over said isolator.

6. The arrangement according to claim 5 wherein said vibration isolator has a thickness of portions subjected to compression on the order of one millimeter.

7. The arrangement according to claim 1 wherein said isolator is molded over said rod end.

8. The arrangement according to claim 1 wherein said housing pieces are molded from a hard plastic.

9. The arrangement according to claim 4 wherein said housing piece isolator receiving cavity has an interference fit with said isolator when said housing pieces are assembled.

10. The arrangement according to claim 1 wherein said retention features comprise a prong on each housing piece projecting into said pin receiving cavity and being radially deflectable to be able to receive a headed portion on said pin and allow passage thereby, and engaging said head of said pin after passage past said prongs.

11. The arrangement according to claim 9 wherein said prongs are each formed with an axially extending wall radially spaced from said core portion and also having a lip projecting inwardly from said wall having a sloping under surface engaged by said head on said pin to cause said radial deflection of said associated prong, and a flat surface engaging said head after said pin head has been inserted past said prongs to retain said pin in said cavity.

12. The arrangement according to claim 1 wherein a web is formed on each housing piece extending over said cavity on one side to prevent insertion of said pin from said one side.

13. A method of connecting one end of a rod to a headed pin, comprising the steps of: molding two hard plastic housing pieces each formed with two generally semicircular recesses, each housing piece able to be fit together to form a pin receiving cavity and an isolator receiving cavity; assembling said housing pieces to form said pin receiving cavity configured to receive said headed pin; pin retention features extending within said cavity so as to engage said headed pin upon insertion therein to retain the same; disposing a soft elastomeric isolator over said one end of said rod; and, enclosing said isolator with said housing pieces upon assembling said housing pieces by enclosing said isolator in said isolator receiving cavity upon assembling said housing pieces together.

14. The method according to claim 13 wherein said step of assembling said housing pieces includes the step of snap fitting said housing pieces together using integrally formed engaging features on said housing pieces.

15. The method according to claim 14 further including the step of snap fitting said housing pieces together extending over said isolator on said rod.

16. The method according to claim 15 further including the step of molding said isolator over said one end of said rod prior to assembling said housing pieces to be fit over said isolator.

17. The method according to claim 13 further including the steps of molding said housing pieces together connected by an integral hinge allowing said housing pieces to be swung into abutment with each other with said recesses forming said cavities.

18. The method according to claim 16 wherein in said step of molding said isolator to said one end of said rod, said isolator is formed with a thin wall on the order of one millimeter in thickness.

19. The method according to claim 13 wherein said step of forming retention features comprises the step of molding an integral prong in each of said hard plastic housing pieces extending radially inward into an associated recess configured so that after said housing pieces are assembled together, they may engage a head portion of said pin upon insertion thereof and be deflected radially outward thereby to allow passage of said head portion and to thereafter engage said head portion to retain the same in said cavity.

20. The method according to claim 19 wherein said prong molding step includes forming a sloping under surface on said prongs to aid in producing radial outward deflection by passage of said pin head portion, and a flat surface on the end thereof engaging said pin head portion to resist extraction whereby a much greater force is required for extraction than for insertion of said pin.