Improvements in, or relating to, trigger valves for pressurised fluid operated devices

The actuation trigger of any one of claims 1 to 21 including an exhaust valve wherein,

• a work load to do the work on, within, or from the working chamber, is driven from a first end of the working chamber to or towards an opposing, second end of the working chamber, using the high pressure working fluid on a rear surface of the workload,
• a fluid pressure is received into a return chamber from a front surface or region of the work load, the fluid pressure formed at least in part as a result of the work load moving down the working chamber towards the second end,
• the exhaust valve, adapted to open as a result of the fluid pressure in the return chamber acting on a working face of the exhaust valve, the exhaust valve, when opened, allowing high pressure working fluid in the working chamber present on the rear surface to exhaust from the working chamber to a lower or ambient pressure location, the high pressure working fluid exiting via the side wall of the working chamber through to the exhaust valve,
• thus producing a pressure difference from the front surface to the rear surface to thus return the work load from the second end to, or toward, the first end.

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, openable under controlled action to allow the charge into the working chamber,
• A trigger valve to selectively supply high pressure working fluid from the high pressure source, to the dose chamber, and to control opening and closing of the dose valve, whether directly or indirectly,
• Wherein when the dose valve is open from the dose chamber to the working chamber, there is no supply from the high pressure source to the dose chamber, whether via the trigger valve or otherwise.

An actuation trigger for a device, comprising or including,

• A trigger valve to selectively control a supply of high pressure working fluid from a high pressure source to one or more operative chambers to in turn control a working chamber, which working chamber uses a charge of high pressure working fluid to act on a work load, wherein the trigger valve has,
• a. A first valve position to supply the one or more operative chambers directly or indirectly from the high pressure source, to a ready to work state, wherein the trigger valve,
• i. Opens supply to the one or more operative chambers, and
• ii. closes any vent path to ambient pressure therefrom, to prepare for, but not for, the working chamber to do work,
• b. A second valve position to actuate the device wherein the trigger valve,
• i. Closes or opens the supply to the one or more operative chambers, thereby allowing the work chamber to be charged and do the work,
• c. A third valve position to make the device safe wherein the trigger valve,
• i. Closes supply from the high pressure source to the one or more operative chambers, or
• ii. discharges the one or more operative chambers to ambient pressure, making the device unable to actuate or inert.

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 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 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.

A method of actuating a device, comprising or including the steps of,

• Charging a dose chamber with a charge of high pressure working fluid,
• Charging a driven chamber on a first side of a hammer, with a high pressure working fluid,
• Charging a trigger chamber on a second side of the hammer with a high pressure working fluid, the first side and second side separated by a piston operatively connected to the hammer, such that the hammer is held in a force imbalance in a first position,
• Releasing the high pressure working fluid from the trigger chamber to drive the hammer to, or towards a second position,
• Actuating a dose valve by the hammer impacting thereon when in, or towards, the second position, to unseat the dose valve from a sealing position, where the dose valve seals the dose chamber from a working chamber, to an unsealed position such that the charge enters the working chamber to do work therein.