A hydraulic hammering device enables an auto-stroke mode and an idle strike prevention mode to coexist with a simple circuit configuration. A first control valve controls advancing and retracting movements of a piston and a second control valve select either the auto-stroke mode and the idle strike prevention mode. To the second control valve, a shared spool is slidably fitted and a mode selection means is disposed. When the mode selection means allows supply of pressurized oil to an auto-stroke setting portion of the shared spool and prohibits discharge of pressurized oil from an idle strike prevention setting portion, the auto-stroke mode is selected. When prohibiting supply of pressurized oil to the auto-stroke setting portion and allowing discharge of pressurized oil from the idle strike prevention setting portion, the idle strike prevention mode is selected.

An actuation trigger for a device, comprising or including, A dose chamber to hold a charge of high pressure working fluid, received from a high pressure source, A dose valve, biased closed to seal the dose chamber off from a working chamber, and hold the charge in the dose chamber, A hammer operated by a piston with a driven chamber on a first side of the piston, and a trigger chamber on a second side of the piston, sealed from the first side, the driven chamber receiving high pressure working fluid directly or indirectly from the high pressure source, A trigger valve to selectively supply high pressure working fluid to the trigger chamber, or to release high pressure working fluid from the trigger chamber, Such that when the hammer has high pressure working fluid in both the driven chamber and the trigger chamber it is held by a force imbalance in a first position, and when the high pressure working fluid is released from the trigger chamber, the hammer is driven to, or towards a second position towards the trigger chamber, The hammer, when driven to, or towards the second position strikes the dose valve, unseating the dose valve to unseal the dose chamber and the working chamber thus allowing the charge to enter the working chamber to do work therein.

An actuation trigger for a device, comprising or including, A dose chamber to hold a charge of high pressure working fluid, received from a high pressure source, A dose valve, biased closed to seal the dose chamber off from a working chamber, and hold the charge in the dose chamber, A hammer operated by a piston with a driven chamber on a first side of the piston, and a trigger chamber on a second side of the piston, sealed from the first side, the driven chamber receiving high pressure working fluid directly or indirectly from the high pressure source, A trigger valve to selectively supply high pressure working fluid to the trigger chamber, or to release high pressure working fluid from the trigger chamber, Such that when the hammer has high pressure working fluid in both the driven chamber and the trigger chamber it is held by a force imbalance in a first position, and when the high pressure working fluid is released from the trigger chamber, the hammer is driven to, or towards a second position towards the trigger chamber, The hammer, when driven to, or towards the second position strikes the dose valve, unseating the dose valve to unseal the dose chamber and the working chamber thus allowing the charge to enter the working chamber to do work therein.

This percussion apparatus includes a striking piston, a control distributor arranged to control a reciprocating movement of the striking piston, and a control device arranged to vary the striking stroke of the striking piston. The control device comprises a plurality of control channels, a control channel connected to the control distributor, a control slide movably mounted between a plurality of control positions, and an adjusting slide mounted in a receiving housing delimited by the control slide, the control slide and the adjusting slide delimiting a first adjusting chamber connected to the control channel and a second adjusting chamber connected to a the high-pressure fluid supply circuit. The control slide is movably mounted between a first position in which the first control chamber and the second adjusting chamber are connected and a second position in which the first control chamber and the second adjusting chamber are isolated.

A hydraulic hammering device enables an auto-stroke mechanism and an idle strike prevention mechanism to coexist with a simple circuit configuration. The device includes a first control valve to control advancing and retracting movements of a piston, an auto-stroke mechanism and an idle strike prevention mechanism, and a second control valve to select either of the auto-stroke mechanism and the idle strike prevention mechanism. To the second control valve, a shared spool is slidably fitted and a mode selection means is disposed. When the mode selection means allows supply of pressurized oil to an auto-stroke setting portion of the shared spool and prohibits discharge of pressurized oil from an idle strike prevention setting portion, the auto-stroke mechanism is selected. When prohibiting supply of pressurized oil to the auto-stroke setting portion and allowing discharge of pressurized oil from the idle strike prevention setting portion, the idle strike prevention mechanism is selected.

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.

In the case of an incorrect polarity of connectors in hydraulic networks, a switching device is provided, and formed with a connector part, a valve body, a switching part displaced axially in the valve body within limits, a base part and a top part. Wherein cooperating annular chambers for the conducting of a working fluid are formed in the region of an inner surface of the valve body and an outer surface of the switching part. Annular surfaces (A2, A3, A5, A7) are acted upon with pressurized fluid on the switching part towards the top part and annular surfaces (A1, A4, A6) of the switching part are acted upon towards the base part have a following size relations when there is a permanent fluidic connection of the annular chambers:

A2=A3>0.5×A1;

A4>A5+A7;

A3+A7>A4+A6;

A1=2A2−A4+A5−A6+A7

Disclosed is a device including an exhaust valve, that operates on a pressurised working fluid. The device includes a working chamber, defined at least in part by a side wall, which working chamber can hold a workload to or toward a first end thereof, the working chamber to receive the working fluid to act on a rear surface of the workload to propel the workload to or towards a second end, opposite the first, of the working chamber. The device also includes a return chamber to receive fluid under pressure from a front surface of the workload, the pressure developed at least in part by the movement of the workload towards the second end. Present also is an exhaust valve fluidly connected to the return chamber, the exhaust valve normally biased closed preventing working fluid from exiting the working chamber, but on receipt of, and action by, the fluid under pressure from the return chamber, will open to allow the working fluid to exhaust the working chamber to a lower pressure location, the working fluid exhausting via the side wall of the working chamber through to the exhaust valve. Provided then is a device that will remove or reduce pressure building on the rear surface of the workload when moved from the second end to the first end.

Provided is a hydraulic striking device in which a reverse operation circuit and a forward operation circuit can switch connection states to a high pressure circuit and a low pressure circuit by means of an operation switching valve. Further, the hydraulic striking device is configured to be selectable between a reverse operation mode or a forward operation mode by operating the operation switching valve. A high/low pressure switching portion is provided with a shortening portion for reducing the time required for high/low pressure switching operation in piston front and rear chambers in association with retraction of a valve to be shorter than the time required for high/low pressure switching operation in the piston front and rear chambers in association with advancement of the valve.

Provided is a hydraulic striking device in which a reverse operation circuit and a forward operation circuit can switch connection states to a high pressure circuit and a low pressure circuit by means of an operation switching valve. Further, the hydraulic striking device is configured to be selectable between a reverse operation mode or a forward operation mode by operating the operation switching valve. A high/low pressure switching portion is provided with a shortening portion for reducing the time required for high/low pressure switching operation in piston front and rear chambers in association with retraction of a valve to be shorter than the time required for high/low pressure switching operation in the piston front and rear chambers in association with advancement of the valve.