Patent GB-1155014-A (GB)
Title: Improvements in or relating to Drive Means
Inventor: FRANKLIN JOHN WARRENDER
IPC: B66F9/075
Filed: 1965-08-03
Abstract: 1,155,014. Electric industrial trucks. CLARK STACATRUC Ltd. 2 Nov., 1966 [3 Aug., 1965], No. 33046/65. Heading B7H. An electric powered industrial truck comprises a single electric motor 14 powered by a battery B1, B2 carried by the truck, which motor powers the truck through driven wheels 12 and drives an hydraulic pump 105 for a load service such as lifting, tilting, turning or clamping. Assuming the truck to be at rest its operation for forward movement is as follows: the direction control 98 is selected for the forward direction and a pedal 20 depressed which is connected to spool 171 of a speed control 21. Movement of the spool to the left will cause micro-switch MS1 to close thus energizing contactor M and closing contact M1 to connect the motor 14 across the corners 115, 116 of the battery bridge circuit. As a result the battery halves B1, B2 are connected across the motor in parallel to provide half the available voltage. The motor shaft 23 in rotating causes sun wheel 24, planet wheels 30, 31 and toothed ring 34 to rotate. Ring 34 drives pinion 35 and thus a control pump 36 which draws fluid from a reservoir 104 and delivers it through line 81 to speed control means 21. The fluid enters means 21 through connection 68, passes through recess 65, passage 74 into recess 71. The fluid then passes through a metering slot 78 into bore portion 61 and through outlet 64 into line 84. From line 84 the fluid passes along line 99 to the control 98 and therefrom along line 100 to the forward clutch 39, 41. Fluid also passes along line 86 to junction 87 and the jack 89 of the power steering. The resistance to pumping of the control pump 36 will increase as the operator presses down pedal 20 causing spool 171 to move to the left and decreasing the area of the metering slot 78 overlapping recess 71. The pump 36 will thus apply more resistance to the ring 34 and the drive will begin to take up through the shaft 37, pinion 38, forward clutch 39, 41, shaft 43, crown wheel 47, differential 49 and half shafts 48 to the wheels 12. As the drive is taken up pinion 54 will drive pump 55 to feed hydraulic fluid to ram 89, along lines 86 and 99 to control 98 and along line 86a to control 21. As the spool 171 continues to move left resistance to pumping of pump 36 will be increased to a maximum when ring 34 is stationary and no further rotation of pump 36 takes place. In the initial position of the control, Fig. 5, no oil will be supplied to the main clutch 26 which will be vented through line 82, connections 69 and 70 to drain 83. However as spool 171 is moved to the left recess 73 will be cut off from recess 72, and this recess will communicate with recess 71 via the reduced portion 77 of the spool. Pressure fluid supplied by pump 55 will pass from connection 68 to line 69 and operate the main clutch 26 so that the epicyclic gear train will rotate in one piece and the gear ratio will be 1: 1. Freewheel drive 36a will prevent the control pump 36 being driven. Movement of the spool 171 further to the left will close micro-switch MS2 to operate solenoid valve 96 so that fluid can pass from line 86 to connection 95. This will move sleeve 57 to the left against the action of spring 62 so that flange 60 seats on end wall 61a. This repositions the spool 171 to its initial relative position with the sleeve and the ring 34 can again revolve and drive pump 36 as before. Simultaneously with the operation of valve 96, the contactor SP will operate through line 122 to close contacts SP1 so that the motor 14 will be connected to the battery halves in series, the diodes D1 and D2 preventing feed back. Thus the full voltage is applied to the motor. Further depression of pedal 20 moves spool 171 to the left until the resistance to pumping is a maximum and the main clutch is engaged as before to give a 1: 1 drive ratio. Had the operator initially selected reverse gear by the control 98 the sequence of operations would have been the same as above except that clutch 40, 44 would have been engaged instead of clutch 39, 41. In order to provide a load service, switch LS is closed thus energizing contact SP and closing contact SP1. The whole voltage is then applied across the motor which drives hydraulic pump 105. Control 109 is conventional in that it sends a signal along servo-line 113 to alter the angle of the swash plate of the pump which then delivers fluid through the control to whichever of the load service cylinders is selected. In a modification, Fig. 6 (not shown), the control 98 is replaced by a pair of forward and reverse pedals each connected to operate the spool 171 of control 21,