Patent GB-821685-A (GB)
Title: Fluid operated driving apparatus
IPC: B41J11/44
Filed: 1955-12-23
Abstract: 821,685. Gear pumps and motors. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 23, 1955 [Dec. 31, 1954], No. 36929/55. Class 110 (2). [Also in Groups XVI and XXIX] A motor is driven at one of two speeds either by providing two pump sections and selectively directing the output of one or both sections to the motor, or by providing a single pump and a valve which in one position by-passes part of the pump output, the remainder passing to the motor, and in a second position closes the bypass so that the entire output passes to the motor. The motor may rotate the platen of an accounting-machine to selectively advance the paper at line space speed and at eject speed. In the embodiment of Fig. 1 a gear motor 14 rotates a platen shaft 11 and is supplied with liquid by gear pump sections 24, 25 under the control of valves 27, 28. Pump sections 24, 25 have a common inlet 32, and in the position of the valves 27, 28 shown, in which valves 27, 28 are held to the right by magnets 45, 55, the section 24 discharges through lines 33, 34 to a drain port 40 of the valve 27 and the section 25 discharges through a line 58 to a drain port 48 of the valve 28. The exhaust line 46 from the motor is cut off from both drain ports. Slow (line-space) speed is obtained on the closure of a cam-operated switch C73 which de-energizes magnet 45 and energizes the magnet 44 so that valve 27 is moved to the left and a detent 65 is removed from a ratchet 64 on the platen shaft. The outlet of pump section 24 is thus closed to the drain port 40 so that liquid is supplied to the motor 14, the exhaust line 46 of which is opened to the drain port 40; and the motor is driven at slow speed. When the desired spacing has been obtained a switch 77 under the control multi-lobed cam on the shaft 11 breaks the circuit of magnet 44 and energizes magnet 45 to restore the initial conditions. Fast (eject) speed is obtained on the closure of a camoperated switch C74 which results in the deenergization of magnets 45, 55 and the energization of magnets 44, 56 so that both valves 27, 28 are moved to the left so that the outlets of pump sections 24, 25 are cut off from drain ports 40, 48 and the output of section 25 passes through a line 59 and check valve 35 to the inlet of the motor 14 so that both sections supply the motor which is thus driven at eject speed. After predetermined movement of the platen a switch under the control of a tape unit 13 energizes magnet 55 and de-energizes the magnet 56 to move the valve 28 to the right and thus by-pass the output of section 25 and restrict exhaust from the motor; the motor being driven at slow speed until a second switch controlled by the tape unit restores the valve 27 to its right-hand end position. In the embodiment of Fig. 2 a motor 14 is supplied by a pump 81, a valve 89 being spring- urged to a position in which the output of the pump passes through lines 85, 87 to a drain port 93, and the motor exhaust line is blocked. Energization of the magnet 104 moves the valve to partly close the line 87 to the drain port and to partly open the motor exhaust to the drain port so that part of the pump output drives the motor at its slow speed. Energization of both magnets 104, 105 moves the valve fully to the left to close the line 87 to the drain port and to fully open the motor exhaust to drain so that the motor is driven at maximum speed. In a modification the detent 65 (for locking the shaft 11) is actuated by a single-acting hydraulic jack subject to the pressure in the exhaust line of the motor.