1. Field
The present disclosure relates to swiveling chairs that include electrically wired devices above the swivel.
2. Description of Related Art
Swiveling chairs may be constructed using a pedestal or legged base supporting a chair seat, and a mechanical swivel, such as a ball bearing, interposed between the seat and the base. A ball bearing swivel may be disposed horizontally between the base and the seat, and bear the weight of the seat and its occupant through the balls and races of the ball bearing. Ball bearings provide a smooth, quiet, and nearly frictionless swiveling action, relative to other bearing types. In such chairs, the ball bearing swivel provides the only practical structure for attaching the seat to the base. As such, the swivel must also carry a tension load to prevent separation of the chair from the base. Separation loads typically vary periodically between zero and peak values as occupants of the chair do not sit perfectly still but instead shift their center of gravity away from the load center of the swivel.
Accordingly, ball bearings used in swivel chairs should be capable of bearing varying tension and thrust loads while swiveling. Certain bearing types, such as precision tapered roller bearings, are designed for bearing axial loads in thrust and can be modified to carry significant tension loads, but are prohibitively expensive for most chair applications. A more cost-effective ball bearing used in many swiveling chairs comprises upper and lower stamped metal plates that fit together to provide a race for steel balls set therein. The plates are axially fastened by a centrally-disposed tension fastener, such as a pin, rivet, or bolt, which bears the tension loads imposed on the swivel by use of the chair and serves as a pivot for the swivel assembly.
The centrally-disposed tension fastener and adjoining two plates form a critical structural part of such swiveling chair assemblies. This part needs to have adequate strength and fracture toughness to last the expected life of the chair without failure, while imparting a feeling of solidity to the chair seat. This is particularly important for seats that include high seat backs, which enhance user comfort but also add a lever arm that can greatly increase tension stress on the swivel when the user leans back. Therefore it is particularly important to provide a robust, yet cost-effective swivel mechanism for high-backed swiveling chairs.
Chairs of both the swiveling and static variety have been provided with wired electrical devices in the seat structure. For example, seats have been wired with audio speakers or with motors for massage devices or other applications. In a static chair, wires can simply be passed through the column pedestal base of the chair into the seat upholstery and routed to the electrical device. In a swiveling chair, an electrical conductor must somehow bridge the swiveling mechanical connection between the base and seat. One solution to this problem is to route a wire from the chair base beyond the outer perimeter of the swivel mechanism and into the upholstery of the chair seat. However, such routing may result in exposing the wire outside of the chair envelope, which is esthetically unattractive. Such routing may also subject the wire to frequent flexure, or to risks of being snagged or cut, which is functionally undesirable. It would be therefore desirable to provide a wired swiveling chair without these and other disadvantages of currently available designs.
A swiveling chair with an electrical pass-though between the base and the seat is disclosed herein, wherein an internally-disposed wire carries an electrical connection between the base and the seat. Advantageously, the chair uses a stamped metal bi-plate ball bearing swivel as the swiveling connection between the base and the seat, providing the cost-effectiveness of this proven design. However, the bi-plate ball bearing swivel is specially modified to allow passage of a wire through a central rotational axis of the swivel. The wire is routed through this axis, avoiding exposure outside of the chair envelope and avoiding significant flexure or breakage risk.
In an embodiment, a bi-plate ball bearing is configured for horizontally mounting between a base and a chair. The ball bearing comprises an upper plate and a lower plate defining a ball bearing race therebetween and a tension member disposed through a central rotational axis of the bi-plate ball bearing holding the upper plate to the lower plate. The tension member may comprises a threaded metal tube fixed to a first one of the upper plate and the lower plate and held to a second one of the upper plate and the lower plate by a nut. The threaded metal tube defines a passage through the central rotational axis of the bi-plate ball bearing.
A chair seat may be attached to the upper plate of the bi-plate ball bearing, and a chair base for supporting the seat above a floor or the like may be attached to the lower plate of the bi-plate ball bearing. At least one electrical wire may pass through the threaded metal tube to provide an electrical connection between the chair seat and chair base, without impairing swiveling action provided by the ball bearing.
An understanding of the swiveling chair with electrical pass-through will be afforded to those skilled in the art, as well as a realization of additional advantages and objects thereof, by a consideration of the following description. Reference will be made to the appended sheets of drawings which will first be described briefly.
Like reference numerals are used to indicate like elements appearing in one or more of the drawings.
The metal tube 106 passes with clearance through a mating opening 108 in the upper plate 102. A plastic spacer 117 positions a torsion spring 116 around the metal tube 106 with ends of the torsion spring disposed against tabs protruding from the upper and lower plates, respectively. The metal tube is welded on the flared edge of the plate and the nut is welded to the tube. A bumper 118 is disposed over one of the tabs in the lower plate as a rotational stop. The upper plate 102 is held snugly against the lower plate 104 by jam nut 110 threaded around an upper portion of the metal tube 106. Washers 112 and 114 are disposed between the jam nut and the upper plate for load distribution and friction reduction. The assembled swivel 100 provides a passage 122 through swivel 100 disposed along its rotational axis 124.
Optionally, a removable cable connector (not shown) can be provided in the cable adjacent to swivel 100 to facilitate assembly and disassembly of the base assembly to the seat assembly. Cable slack for facilitating assembly of the base to the seat, and disassembly of the base from the seat, can be accommodated safely inside of the pedestal 220.
Another example of a swivel 300 with a centrally located electrical pass through for a swiveling chair is shown in
Having thus described a preferred embodiment of swiveling chair with electrical pass-through, it should be apparent to those skilled in the art that certain advantages of the within system have been achieved. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made without departing from the scope and spirit of the present technology. For example, a high-backed chair with speakers has been illustrated, but it should be apparent that the novel concepts described above may be applied by one of ordinary skill to chairs with other form factors or other wired electrical devices in the seat to thereby realize the unexpected benefits described herein.
This application claims priority pursuant to 35 U.S.C. §119(e) to U.S. provisional application Ser. No. 61/260,603, filed Nov. 12, 2009, which application is specifically incorporated herein, in its entirety, by reference.
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