Abstract: A hand held pneumatic grinding tool is provided with two angularly spaced handles (12, 13), one containing an air supply passage (16) and a throttle valve, the other an air exhaust passage (17) and a silencer (15). Both handles (12, 13) are adjustably mounted on the tool housing (10) by means of arc-shaped mountings. These comprise opposed arc-shaped V-grooves (22, 23 and 37, 38) on the housing (10) and mating V-ridges (24, 25 and 35, 36) on the handles (12, 13). Arc-shaped wedge elements (27, 43) are retained by clamping bolts (28, 44) to engage one of the V-ridges (24, 25 and 35, 36) on each handle and, thereby, locking the handles (12, 13) in desired positions relative to the housing (10).

Abstract: In a pneumatically powered portable tool there is provided a speed governor and an overspeed safety device the purpose of which are to ensure a predetermined maximum speed by controlling the air inlet flow to the motor. A cup-shaped shell insert (28) is detachably mounted in the housing (10) to form with the latter an air supply passage (58) and to support the valve means (51,53) of the overspeed safety device. The top surface of the shell insert (28) is exposed through an aperture (57) in the housing (10) and carries the maximum speed marking of the tool.

Abstract: In a pneumatically powered portable tool there is provided a speed governor and an overspeed safety device the purpose of which are to ensure a predetermined maximum speed by controlling the air inlet flow to the motor. A cup-shaped shell insert (28) is detachably mounted in the housing (10) to form with the latter an air supply passage (58) and to support the valve means (51,53) of the overspeed safety device. The top surface of the shell insert (28) is exposed through an aperture (57) in the housing (10) and carries the maximum speed marking of the tool.

Abstract: In a pneumatically powered rotating grinding machine there is provided a safety unit (13) comprising a speed governor and an overspeed release mechanism the purpose of which is to ensure a predetermined maximum speed. For safety reasons, the motor speed must never exceed a certain critical speed level which is determined by the mechanical strength of the working tool attached to the machine. When choosing a working tool to be attached to the machine the maximum speed mark of the machine is decisive. By having a portion of the safety unit exposed through an aperture (57) in the tool housing (10) and having the maximum speed mark (52) of the safety unit (13) located at the exposed portion, the maximum speed mark of the machine will always be the same as that of the safety unit (13). The suggested overspeed safety device avoids the risk involved in the event that a machine carrying a certain maximum speed mark might be erroneously fitted with a safety unit (13) intended for a higher maximum speed.