Torque-limiting clutch comprising a release trigger mechanism

A clutch for a rotary shaft, said clutch comprising an annular chamber, a housing and a thin-walled sleeve forming an axially extended thin wall of the annular chamber, which chamber is arranged to be supplied with a pressurized fluid for substantially elastic deformation of the sleeve, so that a surface of the sleeve engages a smooth complementary shaped surface so that the shaft is drivingly connected to the clutch, the clutch further comprising a trigger device and a channel system activatable by said trigger device upon a relative angular movement between the shaft and the housing, the chamber being connected to said channel system and the channel system being arranged to, when it is activated by said trigger device, assume a state in which the pressurized fluid can flow through the channel system away from the chamber, so that the shaft can rotate independently of the housing, wherein the trigger device comprises a cam wheel, wherein the cam wheel has a substantially constant first radius across a first angular interval and a second radius across a second angular interval, which second radius is smaller than the first radius, wherein in the cam wheel is arranged to be supported on an envelope surface at a contact point being within the first angular interval, wherein the cam wheel is arranged to rotate in relation to the envelope surface as a result of a relative angular movement between the shaft and the housing, wherein the trigger device is arranged to, when the cam wheel rotates so that the said contact point becomes located within the second angular interval, displace the cam wheel radially towards the envelope surface and as a result activate said channel system.