Oil-less rivet system for a reclining chair mechanism

An improved rivet system is disclosed. A wall proximity reclining/tilt chair includes the improved rivet system which eliminates the need for oil lubrication and additional bushings. The rivet system is such that installation is simplified and manufacturing inconsistencies are reduced. In this manner, the rivet system can be installed with less need for quality control confirmations.

FIELD OF THE INVENTION

The present invention relates generally to reclining chairs and, more particularly, to rivets that are used as pivot points such as to allow the chair frame to recline and to extend the legrest of a reclining chair.

Traditionally, reclining chairs are equipped with an actuation mechanism which is operatively interconnected between a prefabricated chair frame and a stationary base assembly. The actuation mechanism is typically a combination of various mechanical linkages operable for providing various comfort features such as independent reclining movement of a seat assembly as well as actuation of an extensible leg rest assembly and associated tilting of the chair frame. Rivet joints are the primary means utilized to fabricate the pivots in these various mechanical linkages. The rivets securely couple the connecting links while allowing a smooth pivoting motion. Some rivet systems utilize an oiled washer to reduce friction within the rivet joint.

Connecting links that are exposed when the legrest is extended are typically coated to prevent oxidation and provide an aesthetically pleasing surface. Coatings that are not electrostatically applied can flake and adversely affect carpet or other flooring. Extreme amounts of flaking may result in damage and carpet replacement. Electrostatic coating the assembly of the connecting links requires a continuous metal-to-metal contact between the connecting links which may not be provided by some rivet systems.

While many conventional reclining chairs operate satisfactorily, furniture manufacturers are continually striving to develop improved actuation mechanisms for reducing system complexity and increasing structural soundness and smoothness of operation. Furthermore, there is a continuing desire to develop improved rivet systems which will result in reduced costs while promoting increased efficiency and improved product quality.

SUMMARY OF THE INVENTION

In accordance with the principles of the present invention, an improved rivet system is disclosed which does not require lubricating oil, which is more simple and less costly to assemble and which reduces manufacturing inconsistencies when compared to conventional rivet systems. The improved rivet system is readily adaptable for use with conventional actuation mechanisms.

In accordance with a preferred embodiment, a wall proximity reclining chair is provided to include the improved rivet system that replaces existing rivets. The rivet system incorporates a plastic bushing to reduce friction within the rivet joint. This rivet system can utilize either a metal wave washer or a plastic spring bushing to reduce the lateral freeplay within the connecting links. A thrust washer between the connecting links of the rivet joint may be metal or plastic with an integral metal contact that provides a continuous electrical path between the links. Elimination of the oiled washer will reduce manufacturing time and eliminate the oiling equipment resulting in reduced manufacturing costs. Additional objects, advantages, and features of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the teachings of the present invention, an improved rivet system for use in single and multi-person articles of furniture (i.e. chairs and sofas or loveseats) is disclosed. A general understanding of the art to which the present invention pertains is disclosed in U.S. Pat. No. 5,570,927 which is commonly owned by the assignee of the present invention and the disclosure of which is expressly incorporated by reference herein. As will be described, the rivet system utilizes a friction reducing bushing that does not require lubricating oil.

With reference toFIG. 1, the article of furniture shown is a combination wall proximity recliner and tilt chair, hereinafter referred to wall proximity reclining/tilt chair10, which includes a pre-assembled actuation mechanism12.

As best seen inFIG. 2, actuation mechanism12of wall proximity reclining/tilt chair10is integrated into and operably suspended from chair frame21and, in particular, from left and right side frame assemblies24. In addition to side frame assemblies24, chair10also includes a front rail assembly26and a rear rail28which, when interconnected, define a rigid “box-like” chair frame. Preferably, most of the structural frame components including side frame assemblies24, front rail assembly26and rear rail28are each constructed in a manner which enables them to support springs, padding, upholstery, etc. in order to complete a decorative and stylish reclining/tilt chair10. More preferably, each of these frame components, except for front rail assembly26and rear rail28, are fabricated from one or more wood panels and/or rails that are fixedly secured together by suitable fasteners, such as dowels, staples, nails and screws, and which may be reinforced at critical joints by metal reinforcement plates or brackets and/or wood corner blocks in a known manner. As previously noted, each frame component is individually pre-assembled for subsequent modular assembly into wall proximity reclining/tilt chair10. However, it is to be understood that the specific construction shown for each frame component is merely exemplary in nature.

With reference toFIGS. 2 and 3, actuation mechanism12is shown to include a drive rod30and front support shaft32, both of which are spatially oriented to be precisely located and “suspended” from left and right side frame assemblies24. In the preferred construction, drive rod30is an elongated square shaft having a manually-operable handle (not shown) secured thereto adjacent an upholstered exterior portion of one of side frame assemblies24and which can be easily reached by a person seated in chair10for convenient actuation thereof. In addition, leg rest assembly16, as shown inFIG. 1, is supported for extensible movement on actuation mechanism12. More specifically, leg rest assembly16includes left and right pantograph linkage mechanisms34which is operable associated with drive rod30and front support shaft32for permitting the seat occupant to selectively actuate leg rest assembly16to response to rotation of drive rod30via the handle.

Referring toFIGS. 4 and 5, pantograph linkage mechanisms34are assembled with rivet joints36and connecting links37. These joints utilize an oil-less rivet system38which allows the connecting links37of pantograph linkage mechanism34to pivot about a pivot axis. These relative rotations of the connecting links37are constrained by the dynamics of the multibar linkage design. Rivet system38is comprised of rivet40, wave washer42, and shoulder bushing44. Rivet joint36is comprised of rivet system38, a larger linkage connection hole46of a connecting link37and a smaller linkage connection hole48of a connecting link37. Rivet40is of unitary construction comprising rivet head50, rivet shoulder52, and tenon54. With reference toFIG. 6, a prior art rivet joint36ais shown that includes fiber washer144interposed between connecting links37a,37b.

As shown inFIGS. 7 and 8, shoulder bushing44is a unitary construction defined by shoulder bushing inner diameter56, shoulder bushing outer diameter58, washer outer diameter60, washer outer face62, washer inner face64, and bushing inner face66. As shown inFIGS. 4 and 5, shoulder bushing inner diameter56rotatably engages rivet shoulder52. Shoulder bushing outer diameter58rotatably engages the larger linkage connection hole46of connecting link37. Smaller linkage connection hole48of connecting link37is sized to fit tenon54. The thickness t1of shoulder bushing outer diameter58is less than the thickness t2of the associated connecting link37to allow wave washer42to fully engage connecting link37. As best depicted inFIG. 4, rivet joint36may contain a third connecting link37by utilizing a rivet40with either a longer rivet shoulder52or longer tenon54. With reference toFIGS. 4 and 5, rivet system38is assembled with a conventional riveting peening method applied to tenon54.

Shoulder bushing44replaces a conventional oiled fiber washer144(as shown inFIG. 6) which functioned as an oil reservoir in a conventional rivet joint. In the conventional system, the rivet joint is assembled and painted using an electrostatic painting process. The fiber washer was then soaked with oil. The conventional system has a shortcoming in that the fiber washer requires lubrication after assembly and painting.

The improved shoulder bushing44is constructed of material that is low-friction and self-lubricating when installed between metal connecting links37, thus eliminating undersired manufacturing inconsistencies. As a preferred embodiment, the shoulder bushing44is fabricated of nylon 6/6. However, a skilled practitioner will recognize that other suitable low-friction self-lubricating plastics may be utilized in the present invention. Rivet shoulder52extends through link37aand shoulder bushing44to provide a metal-to-metal contacts between the rivet40and the link37b. Thus, good electrical conductivity to the links37a,37bis provided by the rivet40and the wave washer42to promote efficient electrostatic painting.

Some conventional rivet systems, as shown inFIG. 6, utilize a bushing that faces the rivet head and floats between the rivet shoulder and first linkage connection hole to reduce rotational friction. The improved shoulder bushing44combines this bushing (if installed) and fiber washer in a one-piece construction to reduce the number of parts required for assembly. Moreover, the link37aand the shoulder bushing44are permitted to slide axially on the rivet shoulder52which in combination with the wave washer42affords greater latitude for dimensional tolerance of the rivet joint36.

Wave washer42provides an axial spring force within rivet joint36to prevent wobble of the joint while concomitantly allowing for tolerance variations in link37athickness. The metal construction of wave washer42provides an electrical circuit throughout pantograph linkage mechanism34which simplifies post-assembly electrostatic painting. As presently preferred, the wave washer is fabricated of a spring steel washer that is plastically deformed to provide the desired force when assembled. However, a skilled practitioner will recognize that other suitable materials and designs may be utilized in the present invention.

With reference toFIGS. 9 and 10a, rivet joint68is shown as an alternate embodiment of rivet joint36wherein rivet shoulder52of rivet40is received within a spring shoulder bushing70. As best seen inFIG. 11, spring shoulder bushing70is of unitary construction and includes a bush portion71having a bushing inner surface72and a bushing outer surface74, and a washer portion75having a washer inner surface76and a washer outer surface78. The washer portion75of spring shoulder busing70is dished with washer inner surface76forming a concavity. Spring shoulder bushing70is preferably constructed of a self-lubricating plastic and more preferably of nylon.

Spring shoulder bushing70is received within a larger linkage connection hole46of a connecting link37where bushing outer surface74and at least a portion of washer inner surface76are in contact with connecting link37. Rivet tenon54is received within a thrust washer80which is interposed between connecting links37. Thrust washer80is preferably constructed of bronze or zinc plated steel to reduce rotational friction between connecting links37and provide an electrical circuit connection between the connecting links37. Tenon54is also received within smaller linkage connection hole48of a connecting link37. A conventional riveting/peening process is used to assemble rivet joint68. When rivet joint68is fully assembled, thrust washer80is preferably in contact with rivet shoulder52. Spring shoulder bushing70applies an axial force acting circumferentially on rivet head50and connecting link37to reduce any wobble associated with rivet joint68.

FIG. 10bdiscloses rivet joint68a, essentially similar in construction as rivet joint68and including a third connecting link37cwith a larger linkage hole46interposed between connecting links37a,37b. A larger bore thrust washer82is interposed between links37aand37cto allow the three links37a,37b,37cto freely rotate. The bushing portion of spring shoulder bushing70in rivet joint68apreferably has a greater axial length than the bushing portion of spring shoulder bushing70in rivet joint68. In this manner, larger linkage hole46of third connecting link37ccan contact the bushing outer surface74which provides for a low friction joint with reduced wobble. Additionally, spring shoulder bushing70reduces the lateral freeplay of pantograph linkage mechanisms34that are associated with the use of wave washer42.

With reference toFIGS. 12a,12b,13aand13b, an alternate embodiment of thrust washers80,82is shown as a low friction thrust washer90. Low friction thrust washer90includes an annular surface92, a central aperture94and at least one eccentric aperture96. Preferably, a plurality of eccentric apertures96(FIG. 12A) are formed in low friction thrust washer90to minimize material requirements. Eccentric aperture96is formed through thickness98of low friction thrust washer90. A metal contact100, as discussed below, is interposed through eccentric aperture96. Low friction thrust washer90is preferably injection molded with a self-lubricating plastic and more preferably of nylon401.

When rivet joints68,68a(FIGS. 10a,10b) are assembled, rivet40is interposed through central aperture94. Central aperture94is sized to accommodate tenon54if low friction thrust washer90is substituted for thrust washer80. Central aperture94is sized to accommodate spring shoulder70if low friction thrust washer90is substituted for thrust washer82.

FIGS. 13aand13bshow metal contact100in a preassembled form. Metal contact100is preferably an extruded brass field rivet that includes a flange102and a shaft104having an outer diameter106and a depth108. Shaft104of metal contact100is preferably hollow with an inside diameter110. When low friction thrust washer90is fully assembled, shaft104is interposed through an eccentric aperture96. Outer diameter106is preferably sized for a slight interference fit with eccentric aperture96. Flange102is secured against annular surface92concentric to eccentric aperture96. Depth108is slightly greater than thickness98. In this manner, distal end112of shaft104can be flared to secure metal contact100within eccentric aperture96. When rivet joints68,68aare fully assembled, metal contact100will abut both immediately adjacent connecting links37. While metal contact100is described as a brass rivet, it would be understood by one skilled in the art that metal contact100could be any electrically conductive material formed with low friction thrust washer90in such a manner so as to allow for electrostatic painting of pantograph linkage mechanisms34.

In this manner, low friction thrust washer90will greatly minimize the metal-to-metal frictional contact surface area within rivet joints68,68awhile providing adequate electrical contact between connecting links37to allow for electrostatic painting of pantograph linkage mechanisms34.