| 摘要 |
<p>A speed responsive engagement device comprises: a wheel arranged for rota tion about a first axis and having a plurality of outwardly projecting space d apart teeth with each pair of adjacent teeth being separated by a circumfe rential surface with a constant radius; a pawl arranged for pivotal movement about a second axis between a first unengaged position and a second engaged position in which the pawl engages one of said teeth and contacts a circumf erential surface; and a resilient means arranged to urge said pawl towards t he first position when the pawl is not in contact with a circumferential sur face. When the wheel rotates in a first direction each tooth contacts the pa wl, generating an oscillating movement of the pawl from the first position t owards the second position with an amplitude dependent on the speed of the r otation. When the speed of rotation reaches a predetermined value the oscill ating movement brings the pawl into the engaged position, preventing further rotation of the wheel in said first direction.</p> |
