Body support structure
A body support structure includes a base, a seat and a backrest, with the backrest connected to the base with a torsion leaf spring. The torsion leaf spring may be configured with a plurality of fingers, and/or one or more flex regions. One or more struts may be connected between the seat or backrest and the base. In another aspect, the seat and/or backrest may be supported with one or more links that provide a counter-intuitive motion. In another aspect, a link may be coupled to a support with a flexible blade.
1. A body support structure comprising:
a base defining a first link;
a seat defining a second link pivotally connected to the base at a first location; and
a backrest defining a third link pivotally connected to the seat at a second location and fixedly connected to the base at a third location, wherein the third link comprises a flexible portion disposed between the second and third locations, wherein the flexible portion comprises a laterally extending deformable link comprising a first flex region and a second flex region positioned outboard of the first flex region, wherein the backrest is pivotable and translatable relative to the base from an upright position to a reclined position as the flexible portion is deformed between an at-rest configuration and a biased configuration as the second location moves relative to the third location.
2. The body support structure of claim 1 wherein the first flex region defines an angle between 20 and 60 degrees relative to a principle axis of the deformable link.
3. The body support structure of claim 1 wherein the second flex region is parallel to a principle axis of the deformable link.
4. A body support structure comprising:
a base;
a seat pivotally connected to the base at a first pivot joint;
a backrest pivotally connected to the seat at a second pivot joint; and
a laterally extending torsion leaf spring having a first portion connected to the base and a laterally spaced end portion connected to the backrest, wherein the torsion leaf spring is bendable about a principal axis and twistable about a laterally extending neutral axis between an at-rest configuration and a biased configuration, wherein the backrest is pivotable and translatable relative to the base from an upright position to a reclined position as the torsion leaf spring is bent and twisted between the at-rest configuration and the biased configuration, wherein the end portion is moveable forwardly as the torsion leaf spring is bent and twisted between the at-rest configuration and the biased configuration, and wherein the torsion leaf spring biases the backrest toward the upright position from the reclined position.
5. The body support structure of claim 4 wherein the backrest and the torsion leaf spring are integrally formed.
6. The body support structure of claim 4 wherein the torsion leaf spring comprises a rectangular cross section.
7. The body support structure of claim 6 wherein the principal axis comprises a first principal axis, wherein the leaf spring further comprises a second principal axis and wherein the neutral axis comprises a longitudinal axis, wherein the torsion leaf spring is bendable about at least the first principle axis, and wherein the torsion leaf spring is twistable about at least the longitudinal axis.
8. The body support structure of claim 7 wherein the end portion comprises a plurality of fingers connected to the backrest.
9. The body support structure of claim 8 wherein at least some of the fingers have a laterally extending portion and a longitudinally extending portion.
10. The body support structure of claim 9 wherein the at least some fingers have an L-shape.
11. The body support structure of claim 8 wherein the fingers are spaced apart along the second principle axis.
12. The body support structure of claim 8 wherein each of the plurality of fingers have lengths less than 50% of an overall length of the leaf spring.
13. The body support structure of claim 12 wherein each of the plurality of fingers have lengths less than 25% of an overall length of the leaf spring.
14. The body support structure of claim 8 wherein at least some of the plurality of fingers have different lengths.
15. The body support structure of claim 4 wherein at least a portion of the leaf spring is solid.
16. A body support structure comprising:
a base;
a seat pivotally connected to the base at a first pivot joint;
a backrest pivotally connected to the seat at a second pivot joint; and
a laterally extending torsion leaf spring comprising an intermediate portion connected to the base and a pair of end portions laterally spaced on opposite sides of the intermediate portion, wherein the end portions are connected to the backrest, wherein the torsion leaf spring is bendable and twistable between an at-rest configuration and a biased configuration, wherein the backrest is pivotable and translatable relative to the base from an upright position to a reclined position as the torsion leaf spring is bent and twisted between the at-rest configuration and the biased configuration, and wherein the torsion leaf spring biases the backrest toward the upright position from the reclined position.