Patent ID: 8051959
Filing Date: 2011-11-08
Classification: F16D

Abstract:
1. A controllable or selectable overrunning coupling assembly adapted for use with pressurized fluid, the assembly comprising: first and second annular coupling members that are supported with respect to each other for relative rotation about a common rotational axis, the first and second coupling members having annular coupling faces that oppose each other and are oriented to face axially along the rotational axis wherein the first coupling member is a stationary member and the second coupling member is a rotating member; the coupling face of the first coupling member having a first set of pockets spaced about the rotational axis, each pocket of the first set having a pivotal reverse strut received thereby; the coupling face of the second coupling member having a second set of pockets spaced about the rotational axis, each pocket of the second set having a pivotal forward strut received thereby wherein centrifugal forces help hold the forward struts in their respective pockets at high rotational speed of the second coupling member; the coupling face of the first coupling member having a first set of locking formations that are engaged by the forward struts upon projecting outwardly from the pockets of the second coupling member to prevent relative rotation of the coupling members with respect to each other in a first direction while permitting relative rotation of the coupling members with respect to each other in a second direction opposite the first direction by pivoting of the forward struts in the pockets of the second coupling member; the coupling face of the second coupling member having a second set of locking formations that are engaged by the reverse struts upon projecting outwardly from the pockets of the first coupling member to prevent relative rotation of the coupling members with respect to each other in the second direction while permitting relative rotation of the coupling members with respect to each other in the first direction by pivoting of the reverse struts in the pockets of the first coupling member; and a control element mounted for controlled, shifting movement between the coupling faces relative to the first set of pockets and operable for controlling position of only the reverse struts without controlling the position of the forward struts, the control element allowing at least one of the reverse struts to engage at least one of the second set of locking formations in a first position of the control element and wherein the control element maintains the reverse struts in their pockets in a second position of the control element and wherein the reverse struts are located along a first line or row radially spaced away from a second line or row along which the forward struts are located wherein geometric dimensions of the second set of pockets resist displacement of the forward struts towards the first coupling member under the influence of centrifugal force when the second coupling member overruns the first coupling member without the need for a control plate or element to control position of the forward struts, thereby reducing spin losses during overrun.