GB2078148A - Drop hammer - Google Patents

Abstract

In a drop hammer apparatus, a hammer (E) is interconnected with a piston (B) by means of a piston rod. An upright cylinder (A) is open at its upper end, the piston is slidable within the cylinder and the piston rod is slidable through the lower end of the cylinder. The space within the cylinder below the piston is selectively connected to a source (C) of pressurised liquid e.g. water and exhausted by means of a valve (D). The apparatus is mainly intended for use above, near or submerged in water. <IMAGE>

Description

SPECIFICATION Drop hammer This invention relates to a drop hammer apparatus.

Drop hammers currently use gas (air or steam), winches or hydraulic power to operate the ram.

The hydraulic systems are closed circuits in which the hydraulic fluid is conveyed to and from the hammer by hose lines and is generally required to pass through a cooling system to absorb the generated heat in the fluid. Such a closed hydraulic system by the use of complicated valves and accumulators etc. can be arranged to provide almost free drop conditions for the ram. This system has the disadvantage of requiring hose lines of sufficient length to reach the location of the hammer and to follow it during its operational cycle. These hoses, especially when the ram becomes heavy and when required to work at a distance from the power unit, as in deep water, become extremely long, large in diameter, and heavy to handle.

The purpose of this invention is to make use of the hydraulic principle to operate the ram without the attendant problems associated with the current use of hoses and closed fluid circuits.

According to the invention there is provided a drop hammer apparatus comprising a hammer, a ram above the hammer comprising an upright cylinder open at its upper end, a piston slidable in the cylinder, a piston rod interconnecting the piston and the hammer and slidable through the lower end of the cylinder, and valve means for connecting the space in the cylinder below the piston to a source of pressurised liquid and for enabling the space to be exhausted.

A form of the apparatus is shown in the accompanying drawing, where a hammer E, is connected to a piston B, which operates inside an open ended cylinder A.

When operated above or near water, the water is used as the hydraulic fluid and is pumped from pressure source C into the cylinder through valve D in one position as shown. This causes the hammer E to rise and at any predetermined stage of this travel, valve D can be moved to its other position, so allowing the piston B and consequently the hammer to fall. By striking any suitable anvil or driving cap then its energy can be utilised.

In a totally submerged situation the surrounding water is used as the hydraulic fluid and is pumped into the cylinder and discharged back into the surrounding water by the valve D.

Consequently there is an unlimited supply of hydraulic fluid with a simple discharge facility.

In this situation it is unnecessary to provide a driving cap on the item to be struck by the hammer since the water between the hammer and the item acts as a cushion and heat that would otherwise be generated by the impacts is immediately dissipated by the water.

It is also envisaged to operate other forms of hydraulic equipment using environmental water.

Accordingly the invention also provides a method of operating hydraulic equipment comprising delivering water from an environmental source to the hydraulic equipment and returning water from the hydraulic equipment to the source.

1. A drop hammer apparatus comprising a hammer, a ram above the hammer comprising an upright cylinder open at its upper end, a piston slidable in the cylinder, a piston rod interconnecting the piston and the hammer and slidable through the lower end of the cylinder, and valve means for connecting the space in the cylinder below the piston to a source of pressurised liquid and for enabling the space to be exhausted.

2. A drop hammer apparatus substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Drop hammer This invention relates to a drop hammer apparatus. Drop hammers currently use gas (air or steam), winches or hydraulic power to operate the ram. The hydraulic systems are closed circuits in which the hydraulic fluid is conveyed to and from the hammer by hose lines and is generally required to pass through a cooling system to absorb the generated heat in the fluid. Such a closed hydraulic system by the use of complicated valves and accumulators etc. can be arranged to provide almost free drop conditions for the ram. This system has the disadvantage of requiring hose lines of sufficient length to reach the location of the hammer and to follow it during its operational cycle. These hoses, especially when the ram becomes heavy and when required to work at a distance from the power unit, as in deep water, become extremely long, large in diameter, and heavy to handle. The purpose of this invention is to make use of the hydraulic principle to operate the ram without the attendant problems associated with the current use of hoses and closed fluid circuits. According to the invention there is provided a drop hammer apparatus comprising a hammer, a ram above the hammer comprising an upright cylinder open at its upper end, a piston slidable in the cylinder, a piston rod interconnecting the piston and the hammer and slidable through the lower end of the cylinder, and valve means for connecting the space in the cylinder below the piston to a source of pressurised liquid and for enabling the space to be exhausted. A form of the apparatus is shown in the accompanying drawing, where a hammer E, is connected to a piston B, which operates inside an open ended cylinder A. When operated above or near water, the water is used as the hydraulic fluid and is pumped from pressure source C into the cylinder through valve D in one position as shown. This causes the hammer E to rise and at any predetermined stage of this travel, valve D can be moved to its other position, so allowing the piston B and consequently the hammer to fall. By striking any suitable anvil or driving cap then its energy can be utilised. In a totally submerged situation the surrounding water is used as the hydraulic fluid and is pumped into the cylinder and discharged back into the surrounding water by the valve D. Consequently there is an unlimited supply of hydraulic fluid with a simple discharge facility. In this situation it is unnecessary to provide a driving cap on the item to be struck by the hammer since the water between the hammer and the item acts as a cushion and heat that would otherwise be generated by the impacts is immediately dissipated by the water. It is also envisaged to operate other forms of hydraulic equipment using environmental water. Accordingly the invention also provides a method of operating hydraulic equipment comprising delivering water from an environmental source to the hydraulic equipment and returning water from the hydraulic equipment to the source. CLAIMS

1. A drop hammer apparatus comprising a hammer, a ram above the hammer comprising an upright cylinder open at its upper end, a piston slidable in the cylinder, a piston rod interconnecting the piston and the hammer and slidable through the lower end of the cylinder, and valve means for connecting the space in the cylinder below the piston to a source of pressurised liquid and for enabling the space to be exhausted.

2. A drop hammer apparatus substantially as hereinbefore described with reference to the accompanying drawing.