Clutch mechanism

本发明提供一种离合机构(200)它具有一个从动轮(32)和一个主动轮(34)，负荷施加到主动轮上；该离合机构(200)具有一个接合位置，在该位置，使用时施加到从动轮(32)上的转矩传递给从动轮(34)；一个分离位置，在该位置，使用时施加到从动轮(34)上的转矩不传递给主动轮(32)，其中该离合机构(200)还具有过负荷控制装置(238，242)，当施加到主动轮(34)上的负荷超过预定值时，使施加到从动轮上(32)的转矩的至少一部分被该过负荷控制装置吸收。 The invention provides a clutch mechanism (200) having a driven pulley (32) and a drive pulley (34) to which a load is applied, the clutch mechanism (200) having an engaged position in which torque applied in use to the driven pulley (32) is transmitted to the drive pulley (34), and a disengaged position in which torque applied in use to the driven pulley (32) is not transmitted to the drive pulley (34), wherein the clutch mechanism (200) also has override means (238, 242) by which at least a proportion of the torque applied to the driven pulley (32) is absorbed when the load applied to the drive pulley (34) exceeds a predetermined value. The override means comprising a pair of detent plates (238, 242), and at least one ball-bearing (248) being held captive between the detent plates (248, 242).