A dynamically piloted spool type gear coupling including a spool having external spur gear teeth around its outer periphery and a sleeve surrounding the spool having internal spur gear teeth around its inner periphery in driving engagement with the spool external teeth and a dynamic piloting means within the spool operative upon rotation of the coupling to diametrically expand the spool for maintaining piloted engagement between the external and internal gear teeth. The piloting means preferably comprises a ring of high density material such as lead in a recess in alignment with the external teeth of the spool. The lead ring expands in response to centrifugal force created by rotation of the coupling and bears against the inner periphery of the spool thereby expanding it radially to maintain piloting.
An oil dam coupling for connecting an output shaft of a transmission arrangement to an input shaft of a pump assembly. The oil dam coupling includes a first member splined to the output shaft and a second member splined to the input shaft. The first member has an end plate which forms a cavity and retains oil within the cavity. The second member engages the first member within the cavity. The oil interacting between the first member and the second member within the cavity will reduce torsional wrap of the output shaft and reduce noise.
A coupling for driving and driven shafts has a first sleeve mounted for axial sliding on the curved teeth of a spool sleeve to accomodate variation of distances between such shafts; oil dam rings are located to provide abutment stops to prevent axial shifting of the sleeves in one arrangement of the sleeves.
