Rotary retardation devices

In a rotary device for angular velocity control in which the retarding torque is substantially proportional to the angular velocity, and which utilizes the deformation of a viscous fluid to create said retarding torque, a construction which includes:

• (a) a first torque member,
• (b) a second torque member mounted for unlimited rotation relative to said first torque member in a clockwise or counter-clockwise direction, and
• (c) a rotating member mounted on one of said torque members for rotation relative to the other of said torque members, and
• that improvement which comprises an annular shallow cavity formed in one of said members having on open side, and a flexible deformable membrane diaphragm overlying said open side to close said cavity, said diaphragm being sealed to the open side of said cavity, and a quantity of viscous fluid in said sealed cavity, said membrane being in contact with a rotating path of one of said torque members,
• whereby a relative rotational movement between said first and second torque members creates a progressive deflection of said diaphragm between said rotating member and one of said torque members causing a progressive shearing of said viscous fluid thereby creating a retarding torque between said first and second torque members.