Patent attributes
A speed responsive engagement device having a rotating wheel having a plurality of outwardly projecting spaced apart teeth with each pair of adjacent teeth being separated by a circumferential surface with a constant radius and a pawl arranged for pivotal movement between an unengaged position and an engaged position in which the pawl engages one of the teeth and a circumferential surface and a resilient means arranged to urge the pawl towards the engaged position when the pawl is not in contact with the circumferential surface. When the wheel rotates each tooth contacts the pawl, generating an oscillating movement of the pawl with an amplitude dependent on the speed of the rotation. When the speed of rotation reaches a predetermined value the oscillating movement brings the pawl into the engaged position, preventing further rotation of the wheel in the first direction.