Torque wrench with release catch - has second order lever transmitting force to first order lever via spring-piston slider

摘要

The torque-wrench uses a combination of second (4) and first order (3) levers to apply adjustable torque to a drive dicating the attainment of a specified torque. The tool has two inter-articulating levers with the opposite end of a handled (7) control-lever pinned to a drive-lever. The drive-lever terminates in the head and the fulucrum (8) locates a short distance from the head. A constant-load spring-piston cursor (5) slides along the two levers (3, 4) into alternative positions graduated on the control-lever (4) and, thus, transmits a constant force at a variable lever arm to the drive-lever (3). The tail of the drive lever stops short of the handle in a ramped face (10) engaged by a recoil-sprung lever-catch (6).