Abstract: Compact damper apparatus for controlling the opposite runs of an endless driving chain passing about a sprocket wheel comprises a pair of oppositely movable spring influenced plungers working in hydraulic fluid filled cylinder bores intercommunicating through a restricted passage. To compact the apparatus, and yet allow it to be mounted with the plungers in an inclined position, the springs are housed in part within the plungers and a single air bleed hole is provided at the highest level inside the hollow interior spring housing part of the uppermost plunger, opening into the plunger/cylinder bore clearance. The proper positioning of this hole allows trapped air which otherwise adversely affects the damping characteristics, to be forced out along the clearance when the apparatus is initially operated, and yet prevents any air being sucked back into the system.

Abstract: In a sprag clutch having individual energising springs, one for each sprag, in which the forces on the sprags during outer race overrunning give rise to only a small rubbing load between the sprags and the clutch inner race at all outer race overrunning speeds within a designed limit, without nevertheless lifting off the clutch inner race, thereby limiting wear on overrun of the clutch, the sprags and the springs are staggered whereby each pair of adjacent sprags of said ring of sprags are offset relative to one another axially of the assemblage, and likewise the pair of springs associated with them, the sprags being shaped and arranged to interengage with one another between the springs to limit the tilt of the sprags in the driving phase of the clutch.