Lumbar support adjustment

Claim 1

A lumbar support assembly including, a support band, a mounting at least at one end of said band, drive mechanism interconnecting said mounting and said one end and being operable to adjust said band between relaxed and tensioned conditions when said assembly is in use, said mechanism including a first part connected to said mounting and a second part connected to said band, said first and second parts having a combined axial extent which reduces or increases according to whether said mechanism is operated to increase or reduce respectively the tension in said band, said first part including a tubular member having an external screw thread of one hand and an internal screw thread of the opposite hand, said external thread cooperatively engaging with a complementary threaded portion of said mounting, said second part including a screw threaded spindle which cooperatively engages with said internal thread, means connecting said spindle to said band one end for movement therewith during said adjustment of band tension, an actuator rotatably mounted on said mounting and connected to said mechanism, said actuator being held against axial movement relative to said mounting by means therefor while being operable to cause rotation of said tubular member about the longitudinal axis thereof relative to both said spindle and said threaded portion, said tubular member being responsive to said rotation to move axially relative to both said threaded portion and said actuator, said spindle being responsive to said rotation to move axially relative to said tubular member and the direction of said axial movement is the same for both said tubular member and said spindle so as to thereby cause said combined axial extent to increase or decrease according to the rotational direction of said tubular member.