Abstract: A gear drive unit of the type including a twin-shaft selective output mechanism is disclosed wherein first and second overrunning clutch mechanisms constituting the twin-shaft selective output mechanism are each composed of a spring-receiving chamber, a coiled spring and a driven gear. The first overrunning clutch mechanism, in response to rotation of a worm wheel in a forward direction, radially expands a first coiled spring to connect the worm wheel and a first driven gear, thereby connecting the worm wheel and a first driven gear to transmit the forward rotation of the worm wheel to the driven gear. Similarly, the second overrunning clutch mechanism is responsive to rotation of the worm wheel in the reverse direction to enlarge the diameter of a second coiled spring, thereby connecting the worm wheel and a second driven gear to transmit the reverse rotation of the worm wheel to the second driven gear.

Abstract: A seal element includes an elastic body of substantially D-shaped cross section and a sealing fin projecting integrally from an arcuate surface of the D-shaped body. The fin is compact and has an elasticity less than the elasticity of the body. The seal element thus constructed is elastically deformable on installation to such an extent that the arcuate surface is urged by the fin to flex inwardly toward an opposite flat surface of the D-shaped body and is held into sealing engagement with the surface of mating joint surfaces along its two longitudinal portions disposed an opposite sides of the fin.

Abstract: A cooling unit for automobile air conditioners includes a pair of scroll-shaped blower cases each composed of an upper case member integrally formed with the upper case member of a cooling case, a lower neck portion integrally formed with the lower case member of the cooling case, and a removable lower case portion detachably disposed between the upper case member and the lower neck portion. The cooling unit also includes a bracket composed of a bracket body integrally formed with the upper case member of the cooling case, and a retaining member detachably connected to the bracket body for holding a blower motor from the below. With this construction, a blower can readily be removed downwardly from the cooling unit by detaching the removable portion and the retaining member even though the cooling unit is mounted on the ceiling of a vehicle.