Abstract: A pneumatic air tool includes a housing with a forward angle gearing arranged in a gearing chamber, a motor chamber, a rear air outlet section and a forward air outlet section. The motor chamber includes a pneumatic motor with air communication openings, which communicate with both the rear air outlet section, and the forward air outlet section. A part of the outlet air is ducted through the forward air outlet section including a circular groove in the housing which form part of a cooling chamber. The walls of the groove form together an enlarged heat transferring surface by which the heat generated in the angle gearing is efficiently transferred to the cold exhaust air from the motor passing through the cooling chamber. By communicating exhaust air through the cooling chamber there is obtained an efficient cooling of the angle gearing while maintaining favorable outer dimensions of the housing.

Abstract: A system for lubricating and reciprocating a piston in a fluid-activated, percussive paving breaker includes a unitary valve assembly positioned within a bore of a rear portion of a tool housing, the valve assembly having an oil reservoir for lubricating the piston. The valve assembly is retained in place by a combination of a throttle lever and a backhead plate bolted to the rear tool housing.

Abstract: A percussive machine having an impact mechanism accommodated to a housing with a hammer piston imparting blows to a rock-destroying member. There is provided an air-supply duct for supplying compressed air to the impact mechanism and to the hole face. In order to prevent the machine from moving away from the hole face during the operation, the housing is provided with an elastic tubular member having a space in constant communication with the air supply duct.