GB530507A - Improvements in and relating to portable riveting presses - Google Patents

Abstract

530,507. Actuating reciprocating pumps for liquids. DESOUTTER, C. March 1, 1939, No. 6734. [Class 102 (i)] [Also in Group XXIX] A self-contained power-operated hydraulic riveting press carried and applied by hand is operated by a piston 18 working in a cylinder 11 supplied with working fluid such as castor oil in two stages the final stage to obtain high pressure being obtained by a pump which makes a number (at least five) of strikes or other incomplete movements to obtain the final pressure. The pump may be operated by an electric or pneumatic motor and as described a pneumatic motor 17, Fig. 1, is operated by compressed air admitted through a pipe connection 31 under control of a hand-lever 30 which operates a valve 25 to control the supply of air. On depression of the valve air is directed via a passage 43 to a casing 15 in which is an elastic bag 16 containing the oil and the air pressure on the bag causes the oil to flow to the upper end of the cylinder 11. Further depression of the valve 25 connects the air to the motor 17 and an eccentric 34 (not shown) on the shaft of the motor operates to reciprocate the piston 55 of a pump which is reciprocated at least five times to build up the pressure in the cylinder 11. The pump discharges its fluid under pressure through the one-way valve 60. The piston of the pump is formed of two parts connected by a spring which can yield to permit the piston progressively to deliver less liquid at higher pressure. The same effect can be obtained by operating the pump by a cam which can yield radially under action of a spring, or by employing a pivoted swash-plate which can yield against spring action. When the pressure on the piston reaches a pre-determined value a valve 89 opens and permits the oil to act upon the valve 76 to return it to the left, thus opening up a passage for the oil to the bag 16.