GB1118691A - Improvements in or relating to pneumatically operated reciprocating tools - Google Patents

Abstract

1,118,691. Power hammers. STANDEL Ltd. 18 May, 1966 [18 May, 1965], No. 20899/65. Heading B3H. [Also in Divisions F1 and F2] A pneumatically operated press tool such as a punch, comprises a piston 154 working in a power cylinder 18 and subjected to differential air pressure on its opposite ends for actuating the tool on its working stroke, and means 20, 200, external to the cylinder are provided for retracting the tool. Pressure air from a supply pipe or a separate compressor, is admitted to cylinder 18 through pipe 30, master control valve 32 and filter 34, and acts continuously on both ends of the piston 154 which carries a piston rod 22 passing through the retraction cylinder 20 and connected to a chuck carrying a punch or die. Within cylinder 20 a piston 200 is secured to the piston rod 22, Fig. 2 (not shown) and pressure air is admitted beneath this piston through duct 202 and valve 204 for raising both pistons 200, 154 and holding them temporarily in their raised position. In this position a guard 92, covering a die or tool on base portion 12, is raised by linkage 88 connected to a hydraulically operated piston rod 60, to enable replacement of the workpiece. The press works continuously and therefore after a delay, as determined by an adjustable valve 130 on a timer device 100, 131, the hydraulic piston rod 60 is released whereby the guard 92 falls by gravity assisted by spring 93. Thereafter valve 204 opens a large exhaust port (234), Fig. 6 (not shown), to exhaust the air below piston 200 thereby causing the tool to move downwardly on its working stroke. Valve 204 may be adjusted by member (224), Fig. 6 (not shown) for controlling the working speed of the tool. The working stroke is cushioned by piston 154 entering a recess (158) in cylinder 18, Fig. 2 (not shown). The press column 14 forms a reservoir in which oil is retained under air pressure; an air filter 132 is provided. Oil for lubricating purposes is supplied to cylinder 18 through pipe 184 from a diaphragm pump 162, Fig. 3, actuated by engagement with the bottom of the hydraulically operated piston rod 60. The pump draws oil from the oil reservoir through pipe 168 and inlet valve 172 and delivers it through outlet valve 178. A porous bronze oil filter 48 in cylinder 18 controls the amount of oil carried by the air. A swarf blower may be connected to pipe 102. The piston rod 22 may alternatively be raised mechanically instead of by piston 200.