An inner subassembly for assembling a valve assembly includes a spool defining a central bore that extends axially through the spool forming a spool annular wall, and including a spool cone tip that is disposed at the first axial end, as well as a hydraulic activation ridge extending radially outwardly from the spool annular wall, and that is disposed axially between the second axial end and the first axial end. The spool may further define a first bypass bore. A stem defines a first flow bore that aligns with the first bypass bore.

A hydraulic hammer is provided. The hydraulic hammer includes a fluid inlet configured to receive a pressurized fluid for running the hydraulic hammer and a fluid outlet for discharging hydraulic fluid from the hydraulic hammer. A bypass passage fluidly connects the fluid inlet and the fluid outlet, the bypass passage has a bypass inlet fluidly connected to the fluid inlet and a bypass outlet fluidly connected to the fluid outlet. An automatic shut-off valve is disposed in the bypass passage between the bypass inlet and the bypass outlet and is configured to open or close the bypass passage. The automatic shut-off valve is configured to open the bypass passage under pressure of the pressurized fluid on continuous running of the hydraulic hammer for a set time to stop the hammer.

A hydraulic hammer is provided. The hydraulic hammer includes a fluid inlet configured to receive a pressurized fluid for running the hydraulic hammer and a fluid outlet for discharging hydraulic fluid from the hydraulic hammer. A bypass passage fluidly connects the fluid inlet and the fluid outlet, the bypass passage has a bypass inlet fluidly connected to the fluid inlet and a bypass outlet fluidly connected to the fluid outlet. An automatic shut-off valve is disposed in the bypass passage between the bypass inlet and the bypass outlet and is configured to open or close the bypass passage. The automatic shut-off valve is configured to open the bypass passage under pressure of the pressurized fluid on continuous running of the hydraulic hammer for a set time to stop the hammer.

An inner subassembly for assembling a valve assembly includes a spool defining a central bore that extends axially through the spool forming a spool annular wall, and including a spool cone tip that is disposed at the first axial end, as well as a hydraulic activation ridge extending radially outwardly from the spool annular wall, and that is disposed axially between the second axial end and the first axial end. The spool may further define a first bypass bore. A stem defines a first flow bore that aligns with the first bypass bore.

The present disclosure generally relates to quick change attachments for a pneumatic percussive tool. The attachments convert a pneumatic percussive tool, such as an air impact tool with proximal attachment, which has a “pushing” force, into a pneumatic percussive tool having a “pulling” force. Once attached to the pneumatic percussive tool, the attachments also provide a quick change feature for allowing “pulling” tools to be simply and easily removed and replaced.

The present disclosure generally relates to quick change attachments for a pneumatic percussive tool. The attachments convert a pneumatic percussive tool, such as an air impact tool with proximal attachment, which has a “pushing” force, into a pneumatic percussive tool having a “pulling” force. Once attached to the pneumatic percussive tool, the attachments also provide a quick change feature for allowing “pulling” tools to be simply and easily removed and replaced.

The invention relates to an impact piston device for an impact drill drive, comprising an impact piston, which is movably mounted in a piston housing so as to be reversible between a front striking position and a rear retracted position, the impact piston having at least one front pressurizing surface and at least one rear pressurizing surface, at least one front pressure chamber and a rear pressure chamber being formed together with the piston housing, a hydraulic fluid feed, a hydraulic fluid drain, a first control device, by which at least the rear pressure chamber for effecting the reversing movement of the impact piston is connected alternately to the hydraulic fluid feed and the hydraulic fluid drain, and a second control device, with which at least one stroke path of the impact piston within the piston housing can be adjusted, the first control device having an actuatable first control valve and the second control device having an actuatable second control valve. According to the invention, it is provided that the first control valve and second control valve are arranged in a common valve housing.

A valve seat has a first valve plate and a second valve plate detachably connected to the first valve plate. The first valve plate has a first trough and at least one pair of first dents, each pair including two first dents capable of respectively forming two first passages with a housing of a pneumatic hammer. The second valve plate has a second trough, at least one pair of second dents, at least one inlet tunnel, and at least two inlet channels. The second trough faces to and communicates with the first trough. Each pair of second dents includes two second dents capable of respectively forming two second passages with the housing. Each inlet tunnel is formed through the second valve plate and communicates with the two second passages. The at least two inlet channels communicate with the second trough and the at least one inlet tunnel.

A valve seat has a first valve plate and a second valve plate detachably connected to the first valve plate. The first valve plate has a first trough and at least one pair of first dents, each pair including two first dents capable of respectively forming two first passages with a housing of a pneumatic hammer. The second valve plate has a second trough, at least one pair of second dents, at least one inlet tunnel, and at least two inlet channels. The second trough faces to and communicates with the first trough. Each pair of second dents includes two second dents capable of respectively forming two second passages with the housing. Each inlet tunnel is formed through the second valve plate and communicates with the two second passages. The at least two inlet channels communicate with the second trough and the at least one inlet tunnel.

The present disclosure generally relates to quick change attachments for a pneumatic percussive tool. The attachments convert a pneumatic percussive tool, such as an air impact tool with proximal attachment means, which has a “pushing” force, into a pneumatic percussive tool having a “pulling” force. Once attached to the pneumatic percussive tool, the attachments also provide a quick change feature for allowing “pulling” tools to be simply and easily removed and replaced.