Patent ID: 7143661

Claim:
A leadscrew mechanical drive comprising: a leadscrew having a leadscrew axis and a leadscrew thread with a nonzero leadscrew thread pitch; a leadscrew follower structure engaged to the leadscrew, the leadscrew follower structure including a threaded insert having an insert thread with a nonzero insert thread pitch different from the leadscrew thread pitch, wherein the insert thread is engaged to the leadscrew over a circumferential distance of less than one-half turn of the insert thread, a bearing in which the threaded insert is received and which permits the threaded insert to rotate about an insert axis that is inclined to the leadscrew axis, and a bearing support in which the bearing is received; and a brake that is selectively engagable to the threaded insert to selectively permit the threaded insert to rotate about the insert axis or prevent the threaded insert from rotating about the insert axis.