The present invention relates generally to the field of seating and in particular to a chair in which the seat and seat back move in concert to provide a reclining position for the user.
There is an ever-present need for economical and temporary seating space that is typically satisfied by the provision of low cost stackable chairs. The use of low to moderate cost stacking chairs is well known in the art. However, such chairs are designed not with comfort or ergonomics in mind, but rather to provide a large quantity of temporary seats for occasional use, which can ordinarily be stored and take up minimal storage space.
Recent years have brought a growing interest in the development of such chairs based on ergonomic designs intended to promote a sitting posture with a maximum of comfort. One aspect of comfort is the ability to adjust the back of the chair to suit the user. Unfortunately, most stacking chairs do not provide any adjustment capabilities and the ones that do merely provide limited flexibility in the seat back portion with little ergonomic benefit. On the other hand, home and office chairs have been produced in a variety of ergonomic designs that have mechanisms for moving the backs of the chairs into a reclining position.
Chairs featuring the ability to adjust for certain preferences of the user relating to seat height, reclining range, and the like are also well known in the art. These features are accompanied by complexity of manufacture and require the use of expensive and complicated mechanisms that are cumbersome or awkward to adjust and may be subject to malfunction. Such chairs are not suitable for stacking nor use for temporary seating.
In the prior art, U.S. Pat. No. 5,944,382 to Ambasz features a chair providing movement of both the seat and seat back. The Ambasz chair features a slideable seat and also a moveable seat back. There is a separate lumbar section between the seat bottom and the seat back making a three-part seat assembly. The seat bottom has a pair of sockets that fit over seat supporting portions of the seat frame to allow the seat bottom to slide forward and aft. The seat back slides up and down and also tilts to the rear to recline. The seat back is mounted on an articulated linkage that includes springs between the seat back and the upper portion of the linkage to bias the seat back in the upward position. Bellows members connect the seat bottom and the lumbar section and the seat back together. The Ambasz design typifies the complexity and expense of most ergonomic chair designs. Moreover, the Ambasz chair does not lend itself to stacking for storage.
One attempt to marry ergonomics with economics is shown in U.S. Pat. No. RE 36,335 to Perry, which discloses a chair having a flexible frame to achieve partial reclining of the seat back. The seat back interconnects the ends of a continuous chair frame with one end projecting upward from the rear legs to the seat back and the other projecting upward from the rear of the seat to the seat back. This two-point connection to the seat back along with curved frame members through the seat back allows limited pivoting of the seat back and also limits pivoting of the seat back. The chair is stackable but of limited comfort, lacking the natural feel provided in a chair having coordinated movement between the seat and seat back.
A need has remained for a chair combining the benefits ergonomic design in a low cost and stackable chair.
Briefly describing one aspect of the invention, a chair featuring a movable seat bottom and seat back is provided. The seat bottom and seat back move in concert between an upright position and a reclined position. The chair includes a frame having a seat bottom support portion and a seat back support portion. In one embodiment, the seat bottom support portion includes a pair of side support members on which the seat bottom is slidably supported. The seat back support portion includes a transverse member to which the seat back is pivotably connected. In one aspect of the invention, this pivotable connection can be accomplished by a plurality of hooks that are preferably molded into the seat back.
The seat bottom and seat back are connected to each other in a manner that allows the seat bottom to slide forward and the seat back to recline in response to the natural forward movement of the seated user's pelvis along with pressure on the seat back from the user. With this feature, the pivotable connection of the seat back to the support frame allows the frame to act as a fulcrum. Specifically, as force is applied to an upper portion of the seat back, the back pivots about the frame, thereby exerting a force on the seat bottom, causing the bottom to slide along the seat bottom support.
In a preferred embodiment, the seat bottom and seat back are most preferably a one-piece molded plastic shell having a resilient intermediate portion interconnecting the seat bottom and seat back. The intermediate portion operates primarily as a deformable and resilient hinge. Secondarily, the resilient intermediate portion can act as a force transmitting element that translates the pivoting movement of the seat back into a fore and aft force on the seat bottom. The natural characteristics of the plastic shell causes it to rebound to the original position without the use of any mechanical devices as the user brings herself back to the non-reclined position or rises out of the chair.
In certain features, the resilient intermediate portion forms a slack region that exhibits a first curvature when the seat is in an original, non-reclined orientation. When the user reclines, the seat back pivots, the seat bottom slides, and the intermediate slack region deforms to a different second curvature. The resilient intermediate region is configured to allow the user to easily recline the seat by leaning back against the pivotable seat back, while the seat back maintains support for the user's back at any angle of recline.
The invention further contemplates the use of rail members and slide blocks to effect sliding of the seat bottom. In one preferred aspect, the upper portions of multiple slide blocks are integral with the underside of the seat bottom. Lower portions of the slide blocks can be combined to form a channel slidably surrounding a corresponding one of the rail members. Stops can be provided at opposite ends of the rail members to limit the fore and aft movement of the seat bottom relative to the seat frame.
In one embodiment of the invention, the chair is provided with legs configured to facilitate stacking, while still retaining the pivoting seat back and sliding seat bottom features. In an alternative embodiment, the chair can be provided with a castered pedestal base for ease of movement. Similarly, the chair can be provided with or without arms. In certain armchair versions, the arms project from the back frame at a slight outward angle and with a slight curvature to provide a comfortable seating experience for the user.
Accordingly, it is one object of the invention to provide an ergonomic chair of relatively simple construction, without mechanical springs or lever devices, and at a reasonable cost. Another object is achieved by features of the invention that allow a user to easily recline the chair while the seat back maintains support for the user's back.
Another object of the invention is to provide a chair with a one-piece molded shell that can be not only reclined, but also easily stacked when not in use. These and other objects, advantages and features are accomplished according to the devices and assemblies, and methods of the present invention.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. The invention includes any alterations and further modifications in the illustrated devices and described methods and further applications of the principles of the invention that would normally occur to one skilled in the art to which the invention relates.
The present invention provides a chair with a synchronously moving seat and seat back. The seat slides forward as the seat back tilts rearward to provide a reclined seating position in response to the natural forward movement of the seated user's pelvis along with the user leaning against the seat back. The resilience of the seat allows it to return to an upright seating position when the pressure on the seat back is removed.
Referring to the drawings, a chair 10 in accordance with one embodiment of the invention is illustrated in FIG. 1. The chair 10 includes a seat assembly 11 and a frame 12. Frame 12, which is preferably of a metal construction such as steel, is shown in detail in
Seat back support portion 16 includes a pair of upright support members 17, and a transverse support element 18 that interconnects the upper ends 19A, 19B of the upright support members 17. Transverse support element 18 is preferably positioned at approximately the center of the seat back when the seat assembly 11 is in place on the frame 12. As shown more clearly in
In one embodiment of the invention, as depicted in
These features provide stability to the chair while in use and also allow the chair to be stacked when not in use. In one embodiment, the configuration of the legs 13 and 15 allows the chair 10 to be stacked with other similar chairs to facilitate storage, as depicted in FIG. 4. In this embodiment, the seat assembly 11, and particularly the seat bottom 32 has a width, and the legs 13 and 15 are flared outwardly to a width greater than the width of the seat bottom to allow the chairs to be stacked.
For certain features of the invention, the configurations of the legs 12, 13 and floor member 14 are not critical and any suitable design is contemplated. Other suitable configurations include, but are not limited to, four-leg, cantilever and caster-based styles.
Returning now to
In a preferred embodiment, the seat back 34 is pivotably supported on the support element 18 by way of a number of connectors 42 that engage the support element. In a preferred embodiment, these connectors are hooks 42A and 42B attached to the seat back 34 as shown in
Center section 18A of transverse support element 18 is a pivot axis or fulcrum about which seat back 34 can pivot or rotate to and from a reclined seating position. The hooks or connectors 42 attaching seat back 34 to the transverse support element 18 are preferably of two types. Referring to
In accordance with certain features of the present invention, any suitable connector 42 is contemplated so long as the transverse element 18 is freely rotatable to ensure smooth movement of the chair. For instance, in an alternative embodiment, hooks 42A could be replaced by mounting pad 40 mounted on seat back 34′, as depicted in
Referring again to
Seat assembly 14 preferably includes a resilient intermediate portion 46 which provides hinge movement, as shown most clearly in
As shown most clearly in
Preferably, seat assembly 14 will be composed of a resilient material at intermediate portion 46. Most preferably, seat assembly 14 is a one-piece shell made from a resilient material, such as polypropylene or other similar materials. However, it is important that the intermediate portion be able to withstand repeated flexing or deformation as the seat is reclined and then returned to its upright position. Most preferably, the intermediate portion 46 is not only resilient, but also sufficiently stiff to transmit force, generated by the pivoting movement of the seat back 34 to the seat bottom 32. This transmitted force can assist the sliding movement of the seat bottom along the frame 12 and assist the return of the seat bottom to its original non-reclined position.
Seat assembly 11 preferably includes at least one slide block 38 connecting seat bottom 32 to frame rails 24, as shown in
Each portion 52, 54 of the slide block 38 defines a channel 58 or upper and lower portions of a bore configured to receive a frame rail member 24. In a preferred embodiment, each half of the slide block 52, 54 also includes a self-lubricating bushing 56 inserted into channels 58. The shape of bushings 56 correspond to that of channels 58. Bushings 56 provide bearing surfaces 60 to reduce friction as the seat bottom 32 slides along the side support members 24. In one particular embodiment, tabs 55 projecting from bushings 56 are receivable in corresponding slots 59 in the slide block upper and lower portions 52, 54 to lock the bushings 56 in position. Tabs 55 are preferably positioned to form an angle of less than about 90°, with a most preferred angle of about 45°. Bushings 56 are preferably made of a material such as polyamide resin, which is preferably harder than the material of the chair seat assembly 11 or the slide block 38 bodies.
In a preferred embodiment, the upper portion 52 of the slide block 38 can be made integral with the lower surface 32A of seat bottom 32. In this embodiment, the side support members or rail members 24 are parallel to each other and extend forward and aft in the direction of motion of seat bottom 32. Also, in a preferred embodiment of the invention, two such slide blocks are used on each side support member. It is contemplated that a suitable number of slide blocks will be used as required for the smooth operation and stability of the chair.
Referring now to
Referring again to
Numerous variations of the invention are contemplated. For instance, the frame rail or side support members 24 can be non-parallel, in which case a channel would be provided in the seat bottom to allow for lateral movement of the slide blocks in response to the divergence of the side support members. Alternatively, the slide block could be modified to include a slot wide enough to accommodate the divergence of the side support members.
In another version of the invention, the side support members could comprise a slotted structure configured to receive a pin attached to the underside of the seat bottom. The slots in the side support members can then act as a channel within which the pin travels as the seat slides back and forth. The length of the channels could determine the extent of motion provided to the seat bottom. Here again, if the side members are not parallel to each other, the seat bottom could include a transverse slot for each pin to allow lateral movement of the pin relative to the seat bottom to accommodate the lateral motion introduced by the non-parallel side support members.
Referring again to
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. It should be understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. For example, arms 64 can be provided to produce an armchair as in
This invention presents an aesthetically pleasing ergonomic chair of simplified design. The simplified design allows the chair to be produced at a reasonable cost. The stackable feature allows the chair to be stored within a minimum of space when not in use. It should be noted however, that the user does not have to change his position relative to the seat bottom of the chair in order to move the chair from an upright to a recline position. The user need only relax and lean back against the seat back. Thus the seating position can be changed without undue ruffling and disturbance of clothing. This provides a further benefit in embodiments in which the chair is upholstered because the movement of the user in the chair does not cause wear on the upholstery. One of the most important features of this invention is that the chair remains comfortable to the user even after long periods of time due to its ability to respond when the user changes seating position. The user merely sits back, and the chair knows what to do.
This application is a continuation of application Ser. No. 09/835,357, entitled “Chair with Synchronously Moving Seat Back”, filed in the name of the same inventor on Apr. 16, 2001 now U.S. Pat. No. 6,722,735.
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Number | Date | Country | |
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20040108761 A1 | Jun 2004 | US |
Number | Date | Country | |
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Parent | 09835357 | Apr 2001 | US |
Child | 10723910 | US |