Chairs and seats – Bottom or back with means to alter contour – Providing support for lower back region
Reexamination Certificate
2000-02-10
2001-10-02
Brown, Peter R. (Department: 3636)
Chairs and seats
Bottom or back with means to alter contour
Providing support for lower back region
Reexamination Certificate
active
06296308
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to mechanisms for adjusting the shape of a back rest, and more particulary to baskets for such mechanisms which conform more closely to the curvature of the human spine.
BACKGROUND OF THE INVENTION
Shape adjusting mechanisms for back rests are well known. Such mechanisms typically include a shaping element, also referred to as a panel or “lumbar basket”, which is mounted for displacement along a guide track. The lumbar basket may have various configurations. A basic construction involves a pair of brackets displaceable along an axis of the guide track, resilient axial ribs joining the brackets and resilient transverse ribs fixed centrally to the axial ribs with free ends extending laterally to either side of the axial ribs to provide a cushioning effect. Various mechanisms can be used to draw the brackets together in order to flex the lumbar basket from a relatively flat rest state to various bowed states. Various mechanisms can also be used to displace the lumbar basket axially along the track. Thus, the curvature of the lumbar basket and its position within a back rest can be adjusted to provide greater comfort.
The basic lumber basket described above has a flexed profile which is essentially a segment of a circle, and consequently does not conform adequately to the curvature of a user's spine. One prior art approach to altering the basic flexed profile involves fixing a partial central rib to an upper bracket and an upper set of the transverse ribs, making the upper end of the basket more rigid. This induces greater flexing of the basket proximate to the lower bracket, providing greater comfort for many users. There are, however, shortcomings to such an approach. Making the partial rib and then fastening it to multiple components of the basic lumbar basket contributes to cost. There is also little freedom to specify the profile ultimately presented by the lumbar basket.
Another approach to altering the basic flexed profile involves stamping each axial rib with reinforcing flanges that extend partially along the length of the rib and produce lengthwise rib sections of different bending resistance that determine the profile of the lumbar basket in its flexed state. This approach provides advantages including reduced manufacturing costs over the above described approach. Despite these advantages there is a continuing need for further reductions in manufacturing costs for the lumbar basket as well as a continuing need to improve the operation and weight characteristics of the lumbar basket.
Another problem with conventional lumbar basket designs is that they may flex in the opposite direction than desired when moved from a rest state to a flexed state. This may pose a safety hazard or at the very least an annoyance to consumers if the basket suddenly snaps from the opposite flexed state. It is desirable that a lumber basket be developed that will not flex in an opposite direction.
BRIEF SUMMARY OF THE INVENTION
In one aspect, the invention provides a basket for a shape adjusting mechanism comprising:
at least one elongate resilient plate having at least one elongate slot defined along a portion of the longitudinal axis of said plate; and
at least one reinforcing flange defined along at least one longitudinal side of said at least one slot to define a region of high bending resistance relative to a controlled arch region in said plate in order that the flex of said plate in said controlled arch region will be more pronounced than in the region with said slot.
In another aspect, the invention provides a shape adjusting mechanism comprising:
a pair of support brackets spaced apart along a predetermined axis;
at least one elongate resilient plate having one end fixed to one of said support brackets and an opposite end fixed to the other of said support brackets such that said plate flexes in a predetermined direction as said support brackets are displaced axially towards one another;
at least one elongate slot defined along a portion of the longitudinal axis of said plate, said slot having at least one reinforcing flange defined along at least one longitudinal side of said slot to define a region of high bending resistance relative to a controlled arch region in said plate in order that the flex of said plate in said controlled arch region will be more pronounced than in the region with said slot; and
means operable to displace said support brackets axially relative to one another thereby to flex said plate.
Other aspects of the invention will be apparent from a description below of preferred embodiments and will be more specifically defined in the appended claims.
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Cosentino Christopher
Maier Tony
Rietveld Jack
Bereskin & Parr
Brown Peter R.
Schukra Manufacturing Inc.
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