Chairs and seats – Movable back – Tiltable
Reexamination Certificate
2000-04-27
2001-11-27
Brown, Peter R. (Department: 3636)
Chairs and seats
Movable back
Tiltable
C297S354120, C016S374000, C016S375000
Reexamination Certificate
active
06322145
ABSTRACT:
BACKGROUND OF THE INVENTION
a. Field of the Invention
The present invention relates to wheelchair seats and, in particular, to a wheelchair seat with a back that can be tilted relative to the bottom of the seat.
b. Prior Art
A typical wheelchair seat has a bottom portion on which the patient sits, and a back portion against which the patient's back rests. The back and bottom portions are typically fixed at a particular angle relative to one another. Wheelchair designs exist that permit the back and bottom portions to be reclined together, without changing the relative angle between the two. That is, when the back portion is rotated backwardly, the bottom portion rotates upwardly.
In some situations such as particular therapies, however, it is preferable to recline the patient's back without changing the angle of the seat bottom. U.S. Pat. No. 4,333,681 to Nelson discloses a wheelchair with a seat back that is controlled with an electric ram. The electric ram has a rod that extends and contracts to recline the wheelchair seat back. The Nelson arrangement requires an electric power source to operate.
U.S. Pat. No. 3,712,671 to Dalton discloses a wheelchair seat back that is pivotally mounted to a hinge pin. The seat back travels along a support, and the seat back may be locked into place along the support by tightening a wing nut. The support extends a substantial distance behind the seat back, and physically extends into the space that the person pushing the wheelchair is likely to occupy.
U.S. Pat. No. 2,165,529 discloses a wheelchair with an adjustable back to which is attached an adjustable ratchet bar. The ratchet bar has a number of detents that are engageable with a stop. The seat back can be reclined backwardly, and the position fixed in place by engaging a detent with the stop. The detents are jagged, however, and present a rough surface onto which the user's clothing can catch.
SUMMARY OF THE INVENTION
It is desirable to provide a wheelchair having a back with a position that can be easily adjusted and firmly secured into place. It is also desirable that the adjustment mechanism have a low profile and does not interfere with the person pushing the wheelchair or with the person riding in the wheelchair.
Broadly defined, the present invention is a wheelchair seat in which the back of the seat can recline relative to the bottom of the seat. In one particular embodiment, the angle of the back of the seat relative to the bottom portion of the seat can be adjusted at any angle within a particular range of angles. The wheelchair seat can have a locking mechanism for the user to engage in order to fix the relative angle between the bottom seat portion and the back seat portion into place once the angle is adjusted as desired.
One embodiment of the invention is a method for adjusting the angle of a wheelchair seat, comprising the steps of (a) providing a system for adjusting the angular position of the backrest of a wheelchair seat, the wheelchair seat having a bottom seat portion and a back seat portion, the system comprising a hinge having a first hinge bracket fixedly mounted to the bottom seat portion and a moving hinge bracket fixedly mounted to the back seat portion, the first hinge bracket being hingedly connected with the second hinge bracket, an adjustment bolt having a head with an aperture, the adjustment bolt extending through the first hinge bracket, a threaded block hingedly mounted on the moving bracket, the adjustment bolt being engaged with the threaded block, and an adjustment tool comprising a handle and a prong, the prong having a head with a shape that is compatible with the aperture in the adjustment bolt. The method also includes the step of inserting the head of the prong of the adjustment tool into the aperture of the adjustment bolt, and rotating the adjustment tool to rotate the adjustment bolt, causing the moving member of the hinge to rotate and the back of the wheelchair seat to change angle relative to the bottom member of the seat.
In particular embodiments of the method, the prong has a hexagonal profile and the head aperture has a hexagonal profile. The adjustment bolt may also have a head, with the system further comprising an adjustment nut threadedly mounted to the bolt, in between the bolt head and the first hinge piece. The moving hinge piece may have left and right side slots, and the threaded block is hingedly mounted to the moving hinge piece with a pin, the pin extending from the left to the right slot.
The method may further comprise the step of securing the angle of the hinge by tightening the adjustment nut against the first bracket. The system may further comprise a bracket, the bracket being fixedly mounted to the seat bottom, and the first hinge piece being mounted to the bracket, thereby fixedly mounting the first hinge piece to the seat bottom.
Another embodiment of the invention is a system for adjusting the angular position of the backrest of a wheelchair seat, the wheelchair seat having a bottom seat portion and a back seat portion, the system comprising a hinge having a first hinge bracket fixedly mounted to the bottom seat portion and a moving hinge bracket fixedly mounted to the back seat portion, said first hinge bracket being hingedly connected with said second hinge bracket. The system also includes an adjustment bolt having a head with an aperture, said adjustment bolt extending through said first hinge bracket. A threaded block is hingedly mounted on the moving bracket, said adjustment bolt being engaged with said threaded block. The system also includes a tool comprising a handle and a prong, said prong having a head with a shape that is compatible with said aperture in said adjustment bolt.
Various other objects and features of the invention will become apparent in the Detailed Description below, in the drawings and in the claims.
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Melgarejo Alejandro
Melgarejo Mauricio
Brown Peter R.
Freedom Designs, Inc.
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