Chairs and seats – Bottom or back with means to alter contour – Providing support for lower back region
Patent
1996-09-09
1997-11-11
Nelson, Jr., Milton
Chairs and seats
Bottom or back with means to alter contour
Providing support for lower back region
2972841, A47C 3025
Patent
active
056856067
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to lumbar supports for use in the backrest of seats, chairs and the like. The invention is especially suited for use with vehicle seats, and it will be convenient to hereinafter describe the invention with particular reference to that example use. In that regard, the word "vehicle" is to be understood as embracing vehicles of all kinds including aircraft, waterborne vehicles and land vehicles.
BACKGROUND OF THE INVENTION
It is well known to provide adjustable lumbar supports in vehicle seats, and especially in the seat to be occupied by the vehicle driver. Such adjustable supports take a variety of forms, and the manner of achieving adjustment also varies widely. The adjustment is generally such that it varies the effective length of the support and/or its stiffness, and thereby influences the extent to which the support curves rearwards in response to pressure applied by the user of the vehicle seat. That is, the support may provide a relatively flat or a deeply curved support for the vehicle seat occupant, according to the level of adjustment of the effective length of the support.
Adjustment of the foregoing kind is sometimes referred to as fore and aft adjustment, which reflects the direction in which the support moves during adjustment under normal use conditions.
Adjustment of the effective length of the lumbar support requires drive means, which may be power driven (e.g., electric) or manually driven. In either case, an actuator is required and that is generally mounted on the seat frame or other support structure, and is connected to the lumbar support through a drive connection such as a flexible cable. Separate mounting of the actuator and the lumbar support adds to the inconvenience and cost of installing the lumbar support assembly.
Another problem encountered with lumbar supports as are currently available, is the need to impose relatively high forces as the lumbar support is adjusted from a deeply curved condition towards a relatively flat condition. The magnitude of the force required increases as the lumbar support flattens.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved lumbar support assembly in which at least part of the drive means for causing adjustment of the lumbar support is mounted on the lumbar support prior to attachment of that support to a seat frame. It is a further object of the invention to provide an improved lumbar support which minimises the forces necessary to adjust the support towards a relatively flat condition.
According to the present invention, there is provided a lumbar support assembly which is characterised in that it includes a flexible band or strap-like member having two relatively movable parts, and drive means which interconnects the two parts and is operable to cause relative movement of those parts in the longitudinal direction of the band so as to thereby cause an increase or a decrease in the effective length of the band. It is preferred that each of the two band parts is elongate and that the band parts overlap at a region of the band which is substantially midway between the ends of the band. The arrangement is such that changes in the extent of the overlap cause changes in the overall effective length of the band. It is further preferred that the drive means which interconnects the two band parts includes a rotatable cam which interacts with the two parts so as to vary the overlap according to the rotational position of the cam. The cam may be driven by an electric motor which is mounted on the band so as to be an integral part of the lumbar support assembly.
In a preferred embodiment of the invention, a series of projections is provided over a front face of the band, and adjacent projections are spaced apart in the longitudinal direction of the band. In one form, the projections adjacent each end of the band have a depth less than that of projections closer to the longitudinal mid-point of the band. Each projection has an outer surface which forms part of
REFERENCES:
patent: 3608960 (1971-09-01), Sherman
Henderson's Industries Pty Ltd.
Jr. Milton Nelson
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