Gardner-denver Company

James R Mayer

Dieter K Palauro

Richard Wayne Adkins

A hydraulic percussion tool for developing repeated impact blows for rock drilling and other high force applications is characterized by a piston hammer reciprocably disposed in a cylinder bore and a tubular valve member coaxial with and actuated by the hammer for controlling the flow of pressurized hydraulic fluid to and from portions of the cylinder bore. The valve member is actuated by the hammer on the return stroke thereof through a column of fluid trapped in an annular chamber formed between a transverse surface on the hammer and an end face of the valve member. Valving mechanism is operable to effect controlled venting of the trapped fluid from the annular chamber to change the position of the valve member with respect to the hammer and thereby control the hammer stroke length, impact blow, and blow frequency.

Hydraulic percussion tool with impact blow and frequency control

In a hydraulic percussion rock drill the operation of the working fluid distributing valve is controlled to effect a variation in percussive blow energy and blow frequency by varying the piston hammer stroke. Actuation of the distributing valve is controlled by a remote controlled hydraulically actuated pressure control valve interposed in a fluid passage which conducts hydraulic fluid from the hammer bore to actuate the distributing valve. Substantially infinite variation of hammer impact blow energy between high and low limits provides for selecting the maximum penetration rate of the drill for any type of rock conditions. The hydraulic rock drill is connected to a source of hydraulic fluid supplied to the drill at substantially constant fluid power by a variable displacement constant power hydraulic pump.

Hydraulic rock drill system

A flexible diaphragm for a hydraulic fluid accumulator is provided with a plurality of concentric circular ridges for engagement with the wall surface of the accumulator housing between concentric circular rows of fluid discharge openings formed in the housing. The ridges maintain the diaphragm in spaced relation to the discharge openings to prevent extrusion of the diaphragm into the discharge openings.

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Denver, CO, United States of America

James R Mayer