CROSS-REFERENCE TO RELATED APPLICATIONS
- FEDERALLY SPONSORED RESEARCH
This application claims the benefit of provisional patent application Ser. No. 61/001,519, filed on Nov. 3, 2007 by Karl S. Weiss.
- SEQUENCE LISTING OR PROGRAM
The application relates to desk or office chairs with knee supports, specifically chairs used at computer stations or other sites that involve long periods of usage.
2. Prior Kneeling Chairs
I. All previous kneeling chairs discussed here will be referred to as a group as “prior kneeling chairs.” The first kneeling chairs were developed in Norway in the 1970s, starting with experimental sitting devices with support under the shins (see, for example, FIG. 1A). By setting the seat at a forward tilting angle and providing knee supports, kneeling chairs change the stress distribution to make it easier to retain the natural curvature of the spine. However, the first generation of kneeling chairs lacked a back support, leading to lower back strain.
II. To address this deficiency, the kneeling chair with back was developed. This design is essentially the same as a kneeling chair, but offers a back support to allow the sitter to rest the back (e.g., BizChair WL-1428-GG, see FIG. 1B). The standard position of the seat, like that of the classic kneeling chair, is in a forward tilt. This places a considerable amount of weight on the knees and upper calves. This weight distribution becomes a painful strain to the knees and calves after a short while. Because of this strain, it is important to be able to shift positions frequently so as to give the knees a rest. This includes being able to get in and out of the chair easily and to adjust the seat angle so the weight can be shifted back. Neither of these goals is served by this model of kneeling chair with back. It is difficult to mount, difficult to maneuver, and fixed in a forward-leaning position. While there is an adjustment of the degree of forward tilt on this model, in order to change this angle, the user must get off the chair and twist an adjustable pole below the seat till it reaches the desired angle. This difficult adjustment makes such a change unlikely or at least infrequent.
III. Other designs have also aimed to make the sitting position and knee support adjustable. In the chair described in U.S. Pat. No. 5,255,957 (see, for example, FIG. 1C), the knee support is attached by a single rod to the wheeled base frame of the chair and supported by a single roller on the floor. However, the patent drawings fairly suggest that the knee support apparatus will tumble to one side as soon as any lateral weight is placed on it.
IV. The knee support in U.S. Pat. No. 4,767,160 (for example, FIG. 1D) suggests more stability, because it is attached to two rods coming from the chair's wheeled base frame and is supported by two rollers on the floor, and is also vertically adjustable. In addition, the patent description and drawings depict the seat as “optionally tiltable.” However, to adjust a new tilt requires two separate adjustments, one of the seat and one of the knee support apparatus. Another disadvantage is the elongated base set on two different sets of casters.
V. U.S. Pat. No. 4,765,684 describes a chair with back and collapsible knee support (see, for example, FIGS. 1E and 1F) that has two basic positions: A) knee support retracted, seat horizontal; B) knee support extended, seat tilted forward. Giving the user the option of using the chair as a regular office chair allows for a variation of postures crucial to maintaining back health. However, these selections are clearly limited, for example, if the user wishes to sit in a horizontal position while still using the knee support. Moreover, the knee support is connected to the vertical support column, rather than the seat base, making coordination of seat angle and knee support require a complicated mechanism.
VI. The Health Postures Stance Angle Chair (see, for example, FIG. 1G) offers the widest range of postures from forward tilt sitting to reclined standing. However, the knee support apparatus is again separate from the main seat structure and at a fixed distance from the seat. The only time the knee support is engaged is in the extreme forward leaning position, as depicted in FIG. 1G. Another major drawback is the fact that the entire apparatus is at least four feet in depth. This makes it unwieldy and difficult to maneuver in small office spaces or tuck readily into work stations. Also, because of the wide range of seat heights, it is necessary to use this chair in conjunction with a hydraulic platform that raises or lowers the keyboard and monitor accordingly. Both these items can cost the end-user a large sum of money.
In accordance with the first embodiment disclosed herein, a computer station chair comprising a swivel chair on casters with adjustable back, knee, and height supports and the capacity to operate with the seat in either a forward tilt or a horizontal position.
In the drawings, closely related figures have the same number but different alphabetical suffixes.
FIGS. 1A to 1G depict kneeling chairs, as discussed in the Background section.
FIGS. 2A to 2D depict the first embodiment of the chair with the seat at horizontal and forward tilt angles and knee support at a suitable angle for use.
FIGS. 3A and 3B depict additional embodiments of the invention disclosed herein, in which the length and angle of the knee support adjust in order to accommodate the individual body size and shape of the user.
FIGS. 4A to 4K depict an additional embodiment of the invention disclosed herein, in which the knee support collapses in order to convert to a conventional computer station chair.
FIGS. 5A to 5D depict an additional embodiment of the invention disclosed herein, in which the knee support assembly functions as a separate attachment which can be added to existing swivel chairs.
DETAILED DESCRIPTION—FIGS. 1A AND 1B—FIRST EMBODIMENT
- 10 five-legged base
- 12 caster
- 14 swiveling, telescoping column
- 16 seat
- 18 back support
- 20 knee support cushion
- 22 knee support poles
- 24 knee support length twist locks
- 26 knee support angle adjustment
- 28 knee support cushion base
- 30 knee support cushion base slot
- 32 seat base
- 34 knee support assembly
- 36 shortened seat
- 38 knee support assembly base
- Operation—FIGS. 2A to 2D
One embodiment of the chair disclosed herein is illustrated in FIGS. 1A and 1B. The chair is mounted on a swiveling, telescoping column 14 supported by a five-legged base 10, each with its own caster 12. A seat 16 is attached to the top of the swiveling column. A knee support assembly base 38 (see also FIGS. 5A and 5C), attached to the seat base 32, suspends a knee support cushion base 28 and knee support cushion 20 from two knee support poles 22. The seat is in a horizontal position, an angle which distinguishes this embodiment from other kneeling chairs. Another distinguishing feature of this embodiment is the suspension of the knee support assembly 34 from the seat base.
- FIGS. 2A to 4K—Additional Embodiments
FIG. 2C depicts how in the horizontal seat position 16, the sitter tucks knees into the knee support cushion 20, the lower back into the back support 18, and the feet behind the legs of the five-legged base (see, for example, FIG. 2C, 10). The horizontal seat angle provides the optimal combination of mobility with an even distribution of weight across the body. An optional adjustment (see, for example, FIGS. 2B and 2D) allows the user to sit a forward leaning position, the seat 16, back support 18 and knee support assembly 34 all tilting forward as a single unit, controlled by a seat tilt lever at the seat base. This places more weight on the knees/upper calves, and less on the back, while still permitting the sitter to keep the lower back tucked into the back support. Another adjustment is in the seat height, accomplished with a pneumatic mechanism on the telescoping, swiveling column 14 depicted in FIGS. 2A and 2B.
- FIGS. 5A to 5D—Alternative Embodiments
Additional embodiments are intended to facilitate individual body sizes and shapes. The first allows adjustment of the length of the knee support cushion 20 (see, for example, FIG. 3A), accomplished by rotating the hand-friendly knee support length twist locks 24 counter-clockwise to loosen, moving the telescoping poles to desired length, and rotating the knee support length twist locks 24 to tighten. The second additional embodiment facilitates adjustment of knee support angle (see, for example, FIG. 3B). The knee support cushion 20 is on a rotating axis, also with a screw-in tightening mechanism, the knee support angle adjustment 26 (see, for example, FIG. 3B). The third additional embodiment enables retraction of the knee support cushion 20 (see, for example, FIGS. 4A to 4K). The exact structure and movements of the knee support length and angle adjustments are displayed in FIGS. 4A to 4K. Note the knee support cushion base slot 30, which lets the knee support cushion slide upwards on the slot in order to fit under the seat in the retracted position. Retraction requires pushing the telescoping poles all the way in and rotating the knee support cushion base 28 down so that it is vertically flush with the front of the seat.
Among the alternative possibilities is a chair that has the seat fixed in the horizontal position. As stated, the horizontal seat angle provides the best balance between mobility and an even distribution of weight across the body (see, for example, FIG. 2C). Moreover, while seat tilt and knee support length and angle adjustments are preferable, the chair can be designed and manufactured successfully without these features. To make the base compatible with bare feet, it might be useful to cushion the legs 10 or even redesign the shape, such as square or hexagonal, to make it easier to tuck the feet into. Other alternatives include the swivel chair with back and knee supports without knee support length and angle adjustments or a collapsible knee support cushion base.
Another alternative embodiment is of the knee support assembly as a separate attachment (see, for example, FIGS. 5A to 5D, 34). This attachment attaches to the base of the seat, as in the first embodiment. Knee support length and angle adjustments can be included in this attachment, which will in turn allow the knee support cushion base to be collapsible. The conventional seat length of non-kneeling swivel chairs, however, is too long to make it possible to tuck the knees into the knee support cushion 20. An important modification, therefore, is that of shortening the length of the seat to about 36 centimeters or 14 inches (see, for example, FIG. 5B, 36).
A further consideration is the width of the knee support cushion 20. This should be at least the width of the seat (approximately 46 centimeters or 18.75 inches) with contoured cushioning to hold the knees/calves in place. Another option is to mount two separate cushions and make the positioning of the cushions adjustable left to right.
From the description above, a number of advantages of the embodiments of the adjustable swivel chair with knee and back supports as disclosed herein become evident to those skilled in the art:
(a) The suspension of the knee support assembly from the base of the seat, as opposed to being built up from the floor as in prior models, makes it possible for a kneeling chair to be mounted on a swiveling column. This structure also allows the seat, back support and knee support assembly to be adjusted for forward tilt as a single unit.
(b) The capacity to use the seat in a horizontal position, unlike prior models, while still engaging the knees in the knee support cushion, provides a unique balance between mobility and an even weight distribution. Tucking the feet into the five-legged base as well means the user can evenly distribute weight to the buttocks, the knees/upper calves, the back, and the feet. This posture also lends itself to more casual use.
(c) Easy adjustment between the horizontal and forward tilt seat positions without getting out of the chair makes it more likely the user will vary positions often, promoting better back health. The forward tilt places more weight on the knees/upper calves, and less on the back, while still permitting the sitter to keep the lower back tucked into the back support. This is in contrast to prior kneeling chairs (e.g., FIGS. 1C and 1F) in which forward leaning and back support are not compatible.
(d) Adjustable knee support length and knee support cushion angle help ensure comfort and support for users of all different sizes and shapes.
- Conclusion, Ramifications, and Scope
(e) Retractable knee support cushion base and knee support cushion makes it possible to switch between a kneeling chair and a conventional computer station chair. The ability to perform this retraction with the same controls that adjust knee support length and angle makes the chair easier and cheaper to manufacture. Compare this to the complicated mechanism displayed in the prior kneeling chair in FIGS. 1E and 1F.
Accordingly, those skilled in the art will appreciate that the multi-adjustable swivel chair with back and knee supports as disclosed herein provides several unique improvements on prior kneeling chair models. White collar workers and recreational computer users spend many hours a day at a computer station, placing a severe strain on the back if improper seating is employed. Kneeling chairs have been an important advance in workplace ergonomics, but so far they have been designed with major limitations and drawbacks. Subsequent designs have addressed some but not all of these issues. The most crucial improvements are the ones that address the need to vary postures and body positions. The multi-adjustable swivel chair with back and knee supports as disclosed herein is an important advance in kneeling chair evolution in that:
- it has a knee support assembly suspended from the seat base that permits the chair to be mounted on a swivel base, permitting much easier movement and use, and easier fitting in small work spaces;
- it permits the user to switch between horizontal and forward tilt seat positions easily and without leaning over or getting out of the chair, using a control lever at the seat base;
- it permits adjustment of knee support length and angle, making it compatible with different body shapes and sizes;
- it permits the user to retract the knee support cushion base and knee support cushion when desired; it has a knee support design that can be manufactured separately as an attachment; and
- it has the capacity to be used with the seat in a horizontal position, permitting a more natural and even weight distribution and more casual use. Examples of casual use can include: a) one knee up and the other foot on the floor, b) one or both feet on the knee support cushion, c) feet on top of the base legs or tucked behind them for additional weight distribution, or d) both feet on the floor.
Although the description above contains many specificities, these should not be construed as limiting the scope of the embodiments but as merely providing illustrations of the presently preferred embodiments. For example, the chair can have no seat tilt adjustment, the knee support can have no adjustments or be adjustable by a different mechanism such as push-in buttons instead of twist locks, the knee support cushion base and knee support cushion might not be collapsible or be retracted by a different mechanism, or the back support can have its own separate adjustment.
Thus the scope of the embodiments should be determined by the appended claims and their legal equivalents, rather than by the examples given.