Adjustable lumbar support

An adjustable lumbar support for use with a seat backrest, said support including a flexible band having a longitudinal axis extending between two opposite ends of the band, each said end being attachable to a respective one of two sides of a said backrest, said band including two separate parts which are relatively moveable in the direction of said longitudinal axis so as to thereby vary the effective length of said band, each said part including a respective one of said ends, and drive means interconnecting the two said parts and being operable to cause said relative movement of said parts, said drive means including a cam which is rotatable relative to said band about an axis extending transverse to said band and which interacts with each of said parts so that said effective length is varied according to the rotational position of said cam relative to said parts, said cam including a disk and at least one camming member attached to said disk for movement therewith, said camming member being located radially outwards of the rotational axis of the cam and cooperating with a cam follower provided on one of said band parts so as to cause said relative movement of the bands parts in response to rotation of said disk.

An adjustable lumbar support for use with a seat backrest, said support including a flexible band having a longitudinal axis extending between two opposite ends of the band, each said end being attachable to a respective one of two sides of a said backrest, said band including two separate parts which are relatively moveable in the direction of said longitudinal axis so as to thereby vary the effective length of said band, each said part including a respective one of said ends, and drive means interconnecting the two said parts and being operable to cause said relative movement of said parts, said drive means including a cam which is rotatable relative to said band and which interacts with each of said parts so that said effective length is varied according to the rotational position of said cam relative to said parts, wherein said cam is caused to rotate through a worm and worm wheel drive connection.

An adjustable lumbar support for use with a seat backrest, said support including a flexible band having a longitudinal axis extending between two opposite ends of the band, each said end being attachable to a respective one of two sides of a said backrest, said band including two separate parts which are relatively moveable in the direction of said longitudinal axis so as to thereby vary the effective length of said band, each said part including a respective one of said ends, and drive means interconnecting the two said parts and being operable to cause said relative movement of said parts, said drive means including a cam which is rotatable relative to said band and which interacts with each of said parts so that said effective length is varied according to the rotational position of said cam relative to said parts, wherein a housing is attached to said band, said cam is contained in said housing, bearing means within said housing mounts said cam for rotation about the rotational axis thereof, and said beating means includes at least one radially outwardly facing surface which slideably engages a radially inwardly facing bearing surface of the cam, said radially inwardly facing surface being a surface adjacent to the radially outer periphery of the cam.

An adjustable lumbar support for use with a seat backrest, said support including a flexible band having a longitudinal axis extending between two opposite ends of the band, each said end being attachable to a respective one of two sides of a said backrest, said band including two separate parts which are relatively moveable in the direction of said longitudinal axis so as to thereby vary the effective length of the band, each said part including a respective one of said ends, and drive means interconnecting the two said inner ends and being operable to cause said relative movement of said parts, wherein said band includes a series of projections which are spaced apart in the longitudinal direction of said band, each said projection extends forwardly from a base of the projection to an outer surface thereof, and each said outer surface forms a respective part of a front surface of the band.