| 摘要 |
<p>A screw actuator comprising first and second relatively rotatable members (10, 14), a screw thread formation in said first member including a helical groove (11), spherical elements (12) carried by the second member and in rolling engagement in said helical groove (11) to form a ball screw coupling between the first and second members, said groove (11) being of sufficient width to allow the spherical elements (12) to move laterally within the groove, and a brake member (15) carried by the second member and defining a screw thread formation (16) which is received in said groove of the screw thread formation of the first member, the brake member being angularly moveable relative to the second member by rotation of the first member relative to the second member, between a first angular position in which the screw thread formation of the brake member is cooperable with that of the first member, and a second angular position in which the screw thread formation of the brake member is not cooperable with that of the first member. <IMAGE></p> |
