| 摘要 |
Contrary to known drive mechanisms where the activating cam acts directly on the pump piston, the cam 26 here moves a piston 24 in an auxiliary pump which at its movement in one direction transfers hydraulic fluid to a chamber 18, thereby moving a piston 16 mechanically connected with the piston 11 of the main pump and with a piston 13 in a preferably pneumatic energy accumulator 14. In this phase, which may take place rather slowly, the piston 11 of the main pump performs its suction stroke and energy is stored in the energy accumulator. By impulse governed opening of a valve 29 in an output pipe 28 from the chamber 18, the three interconnected pistons 11, 13, 16 are released, whereby the pump piston 11 performs its delivery stroke under influence of the energy stored in the energy accumulator. During the return stroke of the auxiliary piston 24 taking place independently of the delivery stroke of the pump piston 11, an amount of fluid corresponding to that flowing out from the chamber 18 during the delivery stroke, flows to the auxiliary pump. The mechanism enables performing of the delivery stroke with high speed at moderate values of the forces acting on the activating cam 26. <IMAGE>
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