Abstract: A hydraulic impact mechanism includes a housing with a cylinder bore, a forward working chamber and a rear working chamber, a hydraulic fluid supply passage connected to the forward working chamber and a drain passage connected to the rear working chamber, a hammer piston reciprocally guided in the cylinder bore for delivering blows to a working implement attached to the housing, a pressure accumulator pre-loaded to a certain pressure level, and a distribution valve for alternatingly connecting the rear working chamber to the supply passage and the drain passage to thereby reciprocate the hammer piston, wherein a sequence valve is provided in the drain passage to keep up the pressure in the rear working chamber so that the resulting forward directed force prevents the piston from being moved backwards in the cylinder bore at pressure levels in the supply passage below the pre-load pressure level of the accumulator.

Abstract: A pneumatic impact tool comprises a housing having pressure air supply passage, and an impact mechanism movably supported in the housing and having a front opening for receiving a working implement and a hammer piston for delivering hammer blows to the working implement. The impact mechanism is supported in the housing by a pivot device in a point located between the forward and rear ends of the impact mechanism and allowing longitudinal and pivotal movements but preventing in the support point radial and rotational movements of the impact mechanism relative to the housing. A resilient membrane is located at a distance from the pivot device and is arranged to bias the impact mechanism to a neutral position relative to the housing while absorbing longitudinal as well as radial vibration movements of the impact mechanism. The membrane has at least one air feed passage connecting the air supply passage to the impact mechanism.

Abstract: A hydraulic impact mechanism includes a housing with a cylinder bore, a forward working chamber and a rear working chamber, a hydraulic fluid supply passage connected to the forward working chamber and a drain passage connected to the rear working chamber, a hammer piston reciprocally guided in the cylinder bore for delivering blows to a working implement attached to the housing, a pressure accumulator pre-loaded to a certain pressure level, and a distribution valve for alternatingly connecting the rear working chamber to the supply passage and the drain passage to thereby reciprocate the hammer piston, wherein a sequence valve is provided in the drain passage to keep up the pressure in the rear working chamber so that the resulting forward directed force prevents the piston from being moved backwards in the cylinder bore at pressure levels in the supply passage below the pre-load pressure level of the accumulator.

Abstract: Hydraulic breaker hammer comprising a housing (10) with a longitudinal bore (12), a cylinder sleeve (14) mounted in the bore (12), a hammer piston (15) sealing guided in the cylinder sleeve (14), a guide sleeve (21) located in the front end portion of the bore (12) for receiving a working implement, and a rear end cover (16) forming a closure for the rear end of the bore (12). The rear end cover (16) comprises a tubular neck portion (17) which is formed integral as a one piece member with the end cover and which extends into the bore (12). The neck portion (17) forms a guide means for the hammer piston (15), and the bore (12) having an axially facing annular shoulder (18), wherein the cylinder sleeve (14) is supported in a correct operating position between the shoulder (18) and the end cover neck portion (17).

Abstract: A hydraulic breaker hammer comprises a housing (10) with a longitudinal bore (12), a cylinder sleeve (14), and a cylinder sleeve (14) engaging rear end cover (16), a hammer piston (15) reciprocally powered in the cylinder sleeve (14) for delivering blows to a working implement inserted in a guide sleeve (20) at the front end of the bore (12), wherein the guide sleeve (20) is provided with radial openings (22a,b) for communication of lubricant from a lubricant supply passage (21) in the housing (10) to the inside of the guide sleeve (20), and the guide sleeve (20) is provided with external seal rings (23 a-d) forming annular compartments located between the lubricant supply passage (21) and the radial openings (22 a,b) for spreading lubricant on the outside surface of the guide sleeve (20), a distribution valve (31) communicating with the pressure fluid source and the cylinder sleeve (14) and comprising both a clearance seal means (44) and a seat seal (45,46) for improved tightness, and a pressure accumulator