A hydraulic hammer is provided. The hydraulic hammer includes a housing member. The hydraulic hammer also includes a power cell disposed within the housing member. The power cell includes an outer casing. The hydraulic hammer also includes a work tool operatively coupled with the power cell. The hydraulic hammer also includes one or more bushing parts arranged within the outer casing of the power cell. The one or more bushing parts are adapted to guide the work tool during an operation of the hydraulic hammer. The one or more bushing parts include a first surface and a second surface spaced apart from the first surface. The hydraulic hammer also includes a wear indicating system for indicating a wear of the one or more bushing parts with respect to the first surface. The wear indicating system includes a first passage and a second passage.

Hammering power of a hydraulic hammering device is improved by shortening a piston stroke, while keeping hammering energy. The device includes a cylinder, a piston slidingly fitted in the cylinder, and a piston front chamber and a piston rear chamber defined between an outer circumferential surface of the piston and an inner circumferential surface of the cylinder and disposed separately from each other at front and rear, respectively, in an axial direction. The device also includes a switching-valve mechanism driving the piston by switching at least one of the piston front or rear chamber into communication with at least one of a high pressure circuit or a low pressure circuit, and an acceleration piston disposed behind the piston and coming in contact with the piston during a retreat stroke of the piston to urge the piston forward in cooperation with braking force by pressurized oil acting on the piston.

A switching method includes starting up a percussion device in acting on a control device arranged to vary the striking stroke of the striking piston between a short striking stroke and a long striking stroke. The percussion device is forced to operate on a short striking stroke for a predetermined period of time from the starting up of the device, and in acting on the control device so as to allow the percussion device to operate on a long striking stroke, after the expiry of the predetermined period of time.

A breaking device includes a frame, an impact device having a pressure chamber with a rear pressure chamber and a front pressure chamber. The breaking device further includes a first low pressure port at the rear pressure chamber, a first low pressure channel and a first low pressure accumulator connected to the first low pressure channel. The breaking device further includes a second low pressure port at the rear pressure chamber substantially opposite to the first low pressure port, second low pressure channel and a second low pressure accumulator connected to the second low pressure channel. The first low pressure accumulator and the second low pressure accumulator are arranged at the outer circumference of the frame of the breaking device at different positions in the axial direction of the breaking device.

A pneumatic drilling device comprising: an impact manifold or cylinder in fluid communication with a rotary air manifold or gear box; and a single air inlet. The single air inlet may be in fluid communication with the impact manifold or cylinder.

An apparatus including an accumulator and a drive mechanism. The accumulator includes an energy storage apparatus with a first piston face configured to reversibly compress an energy storage medium and a second piston face forming at least part of an inner surface of a corresponding second fluid chamber reversibly expandable by movement of the second piston face. A third piston face forms at least part of an inner surface of a corresponding third fluid chamber reversibly expandable by the third piston face. The first, second and third piston faces are coupled together

A hydraulic hammer for impact fracturing a work object includes a hammer shell having a cylinder body disposed between a front head and a rear head. A piston reciprocally movable within the cylinder body abut a work tool and can extend and retract the work tool from the hammer shell. To dampen momentum and impact forces, an accumulator head is attached to the back head and can accommodate hydraulic and dampening fluids in separate first and second sub-chambers. The dampening sub-chamber may directly fluidly communicate with an internal dampening fluid reservoir in the back head.

The invention relates to a cylinder cover for a cylinder of a piston mechanism. In certain embodiments, the cylinder cover includes a cylinder cover body, a valve plate, and a one-directional valve. The cylinder cover body has an exhaust port, and an oil intake. The exhaust port and oil intake are disposed on outer circumference of the cylinder cover body. The one directional oil valve is formed by a compression spring and a ball. An inner end of the oil intake is connected to the compression spring through the ball and the ball is disposed between one end of the compression spring and the inner end of the oil intake. The valve plate is retained on an inner wall of the cylinder cover body by a retaining nut. The cylinder cover further has an auxiliary heating rod inside cylinder cover body for pre-heating cylinder cover to a predetermined temperature.

An automatic shutoff system for a hydraulic hammer is disclosed. The automatic shutoff system may include an inlet groove formed around a piston associated with the hydraulic hammer and configured to receive pressurized fluid, and an outlet groove formed around a piston associated with the hydraulic hammer and configured to discharge the pressurized fluid. The automatic shutoff system may also include an annular passage configured to allow the pressurized fluid to flow between the inlet and outlet grooves. The automatic shutoff system may further include a valve disposed upstream of the inlet groove and configured to selectively block the pressurized fluid from flowing into the inlet groove based on an operational state of the hydraulic hammer.

A hydraulic hammer includes a power cell. A work tool is partially received in, and movable with respect to, the power cell. A sleeve is positioned in the power cell that defines a centerline. A piston is concentrically positioned in the sleeve and movable in the sleeve between a first position in contact with the work tool and a second position out of contact with the work tool. A magnetic guide system includes at least one of a first magnetic guide component disposed in the piston and at least one of a second magnetic guide component disposed in the sleeve that interact to produce magnetic repellent forces therebetween to urge the radial position of the piston towards the center line.