| 摘要 |
The attachment comprises a body with one end for acceptance in a power tool. The body has an abutment 28 which transfers axial force via a rigid spring 18, e.g. an O-ring, wave washer or coil spring, to an abutment of an external sleeve. The sleeve has a torque- limiting recess 48 of variable axial dimension biased to its longest position by the rigid spring 18. Under normal drive conditions, the rigid spring will maintain the torque-limiting recess at its maximum length position. For application of additional torque to a fastener head 38, an extraordinary axial load is applied which collapses the rigid spring and enables the operation to reengage a body polygonal bore 32 with the fastener head. The fastener- engaging surfaces presented by the tool could alternatively be in the form of a driver bit retained in the polygonal bore by set screw 14. <IMAGE> |
