Claims
- 1. A chair comprising a leg including a support having first and second carriers; a seat on said first carrier; a back rest on said second carrier; and means for movably coupling said carriers to each other, including a slotted portion provided on one of said carriers, a slide portion provided on the other of said carriers and movable in said slotted portion between a plurality of positions in and counter to a predetermined direction, and detent means including cooperating first and second detent elements which are movable relative to each other and are respectively provided on said slide portion and said one carrier and have means for releasably holding said slide portion in selected ones of said plurality of positions.
- 2. The chair of claim 1, wherein said holding means include complementary teeth extending transversely of said direction and being in frictional mating engagement in each of said selected positions in the absence of transmission of stresses to the second carrier by said back rest.
- 3. The chair of claim 2, wherein said first detent element includes a toothed rack having tooth spaces, at least one for each of said selected positions, said second detent element including a holder and means for movably mounting said holder on said one carrier, said holder having at least one tooth and said at least one tooth being received in a different tooth space in each of said selected positions.
- 4. The chair of claim 3, wherein said holder includes a lever which is pivotally mounted on said one carrier and has at least one arm, said at least one tooth being provided on said arm.
- 5. The chair of claim 3, further comprising means for biasing said at least one tooth against the adjacent tooth of said rack in each selected position of said slide portion in the absence of transmission of stresses from the seat and/or back rest.
- 6. The chair of claim 3, wherein the teeth of said rack have flanks which are engaged by said at least one tooth in the corresponding selected positions of said slide portion, said flanks being disposed in substantially parallel planes extending substantially at right angles to said direction.
- 7. The chair of claim 3, further comprising means for yieldably urging said holder in a direction to disengage said at least one tooth from said rack.
- 8. The chair of claim 7, further comprising means for moving said holder against the opposition of said urging means so as to engage said at least one tooth with said rack.
- 9. The chair of claim 8, wherein said moving means includes a motion transmitting member movable to a releasing position in which said urging means is free to disengage said at least one tooth from said rack.
- 10. The chair of claim 7, wherein said holder includes a pivotable bell crank lever including a first arm for said at least one tooth and a second arm, and further comprising means for pivoting said lever in a direction to engage said at least one tooth with said rack, said pivoting means including a motion transmitting member connected with said second arm and a mechanism for moving said motion transmitting member.
- 11. The chair of claim 10, wherein said moving means further comprises an elastic cushion between said mechanism and said motion transmitting member.
- 12. The chair of claim 11, wherein said motion transmitting member includes a rod which is reciprocable by said lever and by said mechanism and includes a retainer for said cushion, said mechanism including an actuator for said rod and said cushion including a spring reacting against said actuator and bearing against said retainer.
- 13. The chair of claim 3, wherein said rack has an opening extending in said direction and at least one row of teeth disposed in said opening and extending in said direction, said second detent element having at least one tooth movable into and from said opening to engage a different tooth of said row in each selected position of said slide portion.
- 14. The chair of claim 13, wherein sLid rack has an additional row of teeth parallel to said at least one row, said second detent element having at least one additional tooth movable into and out of mesh with the teeth of said additional row.
- 15. The chair of claim 14, wherein said second detent element has a first set of several teeth movable into and out of mesh with the teeth of said at least one row and a second set of several additional teeth movable into and out of mesh with the teeth of said additional row.
- 16. The chair of claim 13, wherein said rack includes a plate having a thickness of less than one centimeter and said at least one tooth has a depth which at least approximates said thickness.
- 17. The chair of claim 1, wherein said support is hollow and said detent means is installed in said support.
- 18. A chair comprising a leg including a support having front and rear carriers; a seat on said front carrier; a back rest on said rear carrier; means for movably coupling said carriers to each other so that the rear carrier is movable forwardly and backwards with reference to said front carrier, including a slotted portion on said front carrier, a second portion provided on said rear carrier and movable forwardly and backwards in said slotted portion between a plurality of positions, first teeth provided on said second portion, a lever pivotably mounted on said front carrier and having second teeth adjacent said second portion, and means for pivoting said lever in a first direction to engage said second teeth with said first teeth in a selected position of said second portion in said slotted portion; first spring means for biasing said lever in a second direction to disengage said second teeth from said first teeth; and second spring means for biasing said second portion in a direction to maintain said second teeth in frictional engagement with said first teeth with a force which exceeds the bias of said first spring means, said back rest being pivotable backwards with reference to said seat to thereby reduce the force of said second spring means upon said second portion and to thus permit disengagement of said second teeth from said first teeth under the action of said first spring means so that said second portion can be moved in said slotted portion to any one of said plurality of positions.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 3629882 |
Sep 1986 |
DEX |
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 262,101, filed Oct. 18, 1988, now abandoned which is a continuation of Ser. No. 092,328, filed Sep. 2, 1987, now abandoned.
The chair of the present invention is similar to the swivel chair which is disclosed in the commonly owned copending patent application Ser. No. 092,325 filed Sep. 2, 1987 by Fritz Makiol for "Swivel Chair".
The invention relates to seating facilities in general, and more particularly to improvements in chairs, especially swivel chairs. Still more particularly, the invention relates to improvements in chairs of the type wherein the seat and/or the back rest is adjustable, especially in such a way that any, or at least certain, adjustments of one of these parts involve an automatic adjustment of the other part.
It is known to mount the seat and the back rest of a chair, such as a swivel chair, on a support which is located at the upper end of an upright column forming part of the leg of the chair. The seat is pivotable forwardly and backwards, the same as the back rest. It is also known to provide a specially designed coupling which movably connects the seat with the back rest in such a way that these parts can perform translatory as well as angular movements relative to each other. To this end, the seat or a carrier which is secured to the seat is provided with an elongated slot, and the back rest or a carrier which is connected to the back rest has a slide which is reciprocable in the slot. The positions of the slot and slide can be reversed, i.e., the slot can be provided in the back rest or in a carrier which shares the movements of the back rest. The adjusting mechanism for moving the seat and the back rest relative to each other in directions which are determined by the coupling normally comprises a gas spring (e.g., an air spring of the type disclosed in commonly owned U.S. Pat. No. 4,603,905 granted Aug. 5, 1986) which can begin to change the positions of the seat and back rest relative to each other in response to disengagement or loosening of a suitable locking device, e.g., a handle which is to be manipulated by hand. An important function of the gas spring is to damp the movements of the seat and back rest relative to each other, i.e., to prevent abrupt extensive changes in mutual positions of the seat and back rest such as could startle and/or injure the occupant of the chair.
It has been found that a gas spring is not always reliable, especially after extensive wear. Therefore, attempts were made to use conventional extension and/or compression springs. However, a standard mechanical spring which is called upon to store a substantial amount of energy will invariably tend to rapidly dissipate energy when permitted to do so; therefore, chairs employing adjusting mechanisms with such springs are also likely to startle or even injure the occupant who wishes to change the inclination of the seat and back rest. For example, the back rest is likely to abruptly pivot and/or otherwise move from a rearwardly inclined position to an upright position to thereby strike the back of the occupant or to propel the occupant forwardly if the body of the occupant is in contact with the back rest when the latter is permitted to move in response to abrupt dissipation of energy by one or more strong compression or extension springs.
European Pat. No. 0 001 846 B1 discloses a chair wherein the means for biasing the back rest comprises a standard spring and the inclination of the back rest can be altered only in response to the application of a force which acts upon the back rest and tends to pivot it rearwardly. A drawback of the chair which is disclosed in this patent is that the adjusting mechanism occupies an inordinately large amount of space and cannot be readily installed in a compact chair.
German Auslegeschrift No. 23 41 790 discloses a swivel chair wherein a coil spring urges the back rest to its foremost position and the rigid frame of the seat is connected with a box-like part which is pivotably connected with a box-like forwardly extending first arm of an L-shaped lever having an upwardly extending second arm which supports the back rest. The upwardly extending arm contains a mechanism which can raise or lower the back rest. The first arm of the lever carries a pivotable gear segment adapted to be locked in a selected position by a pawl which is pivotable by a handle. The inventors named in this publication are concerned with a modular adjusting mechanism which can be designed to afford greater or lesser comfort to the occupant of the chair, depending on the cost of the chair.
An object of the invention is to provide a chair, such as a swivel chair, which is constructed and assembled in such a way that the movements of the back rest and/or seat relative to the support for such parts can be damped and otherwise controlled even if the adjusting mechanism of the chair does not employ a gas spring.
Another object of the invention is to provide novel and improved means for preventing abrupt changes in the position of the back rest and/or seat with reference to its support.
A further object of the invention is to provide a chair wherein the back rest and/or the seat can be biased to an end position by one or more strong or very strong springs without the danger of startling, shocking and/or injuring the occupant during adjustment.
An additional object of the invention is to provide a novel and improved coupling between relatively movable parts of a chair having an adjustable seat and/or back rest.
Still another object of the invention is to prevent abrupt forward propulsion of the back rest of a swivel chair or a similar seating facility in response to disengagement of the mechanism for releasably locking the back rest and/or the seat in a selected position.
A further object of the invention is to provide a novel and improved detent mechanism for use in the above outlined chair.
Another object of the invention is to provide a novel and improved connection between mutually movable parts of a support for the back rest and seat in a swivel chair.
An additional object of the invention is to provide a novel and improved method of controlling the movements of the back rest and/or seat in a swivel chair from one end position toward the other end position.
A further object of the invention is to provide a novel and improved support for use in the above outlined chair.
The invention is embodied in a chair which includes a leg comprising a support which has first and second carriers, a seat on the first carrier, a back rest on the second carrier, and means for movably coupling the carriers to each other. The coupling means comprises a slotted portion provided on one of the carriers, a slide portion provided on the other carrier and being movable in the slotted portion between a plurality of different positions in and counter to a predetermined direction, and detent means including cooperating first and second detent elements which are movable relative to each other and are respectively provided on the slide portion and the one carrier. The detent elements have means for releasably holding the slide portion in any one of several selected positions of the plurality of different positions. The holding means preferably include complementary teeth provided on the first and second detent elements and extending transversely of the predetermined direction. Such complementary teeth are in frictional mating engagement with each other in each of the selected positions in the absence of transmission of stresses to the second carrier by the back rest and while the seat is not acted upon by a force (e.g., by the weight of the occupant of the chair) or is acted upon by a force tending to pivot the set rearwardly.
In accordance with a presently preferred embodiment of the invention, the first detent element includes a toothed rack having tooth spaces between its teeth, at least one tooth space for each selected position of the slide portion. The second detent element then comprises a holder and means for movably mounting the holder on the one carrier so that the holder does not share the movements of the slide portion with reference to the one carrier. The holder has at least one tooth which is received in a different tooth space of the rack in each selected position of the slide portion. The holder can include a lever which is pivotally mounted on the one carrier and has at least one arm. The at least one tooth of the second detent element is provided on such arm.
The chair further comprises means for biasing the at least one tooth against the adjacent tooth of the rack in each selected position of the slide portion in the absence of transmission of stresses from the seat and/or back rest to the respective carrier or carriers of the support. The teeth of the rack have flanks which are engaged by the at least one tooth in the corresponding selected positions of the slide portion, and such engaged flanks are disposed in substantially parallel planes which are preferably normal or nearly normal to the predetermined direction.
The chair preferably further comprises means for yieldably urging the holder in a direction to disengage the at least one tooth from the rack, and means for moving the holder against the opposition of the urging means so as to engage the at least one tooth with the rack. The moving means can include a motion transmitting member which is movable to at least one releasing position in which the urging means is free to disengage the at least one tooth from the rack.
The lever can constitute a bell crank lever with a first arm for the at least one tooth and a second arm, and the moving means then includes means for pivoting the bell crank lever in a direction to disengage the second detent element from the first detent element. The motion transmitting member of the pivoting means is connected with the second arm, and the moving means further comprises a mechanism for moving the motion transmitting member. An elastic cushion can be interposed between the mechanism and the motion transmitting member. For example, the motion transmitting member can constitute or include a rod which is reciprocable by the lever (in one direction) and by the mechanism (in the opposite direction) and includes a collar or an analogous retainer for the cushion. The mechanism can include an actuator for the rod, and the cushion can include a spring (e.g., a coil spring) which reacts against the actuator and bears against the retainer.
In accordance with a modification, the rack can include a plate with an opening (e.g., a window) which extends in the predetermined direction, and the plate has at least one row of teeth which are located in the opening and the row extends in the predetermined direction. The second detent element of such detent means has at least one tooth which is movable into and from the opening to engage a different tooth of the row of teeth in the opening in each selected position of the slide portion. The rack can be provided with an additional row of teeth which row is parallel to the at least one row, and the second detent element then comprises at least one additional tooth which is movable into and out of mesh with the teeth of the additional row. The arrangement may be such that the second detent element has a first set of several teeth (e.g., five teeth) which are movable into and out of mesh with the teeth of the at least one row, and a second set of several (e.g., five) additional teeth movable into and out of mesh with the teeth of the additional row. The thickness of the plate-like rack can be less than one centimeter (e.g., two, three or four millimeters), and the at least one tooth can have a depth which equals or approximates the thickness of the plate-like rack.
The support (or a portion of the support) is or can be hollow, and the detent means is or can be installed in the interior of such support.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved chair itself, however, both as to its construction and the mode of operating the same, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.
US Referenced Citations (4)
Continuations (2)
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Number |
Date |
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| Parent |
262101 |
Oct 1988 |
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| Parent |
92328 |
Sep 1987 |
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Patent Grant
4943115
