Patent GB-449330-A (GB)
Title: Improvements relating to lifts
IPC: B66B9/04
Filed: 1935-01-05
Abstract: 449,330. Vehicle lifts; platform loadhandling machines. BENNIE LIFTS, Ltd., BENNIE, J., and GIRVAN, J., 28, Medway Street, Westminster. Jan. 5, 1935, No. 459. [Class 78 (iii)] In a platform vehicle lift of the kind in which a turntable is mounted on the platform, both the platform and the turntable are substantially oblong in shape and of dimensions little greater than the maximum dimensions of the vehicles to be transported, and the platform serves to close an oblong floor opening when the turntable 1 is swung over the floor. Raising and lowering is prevented except when the turntable is in the hoisting position and limit switches also are fitted to act somewhat similarly to a floor-levelling device. The driving motor can be disconnected and used for other purposes. Fig. 1 shows a lift serving a ground floor and a basement, comprising a vehicle-supporting platform 4 raised by a fluid-pressure ram 3 and provided with a canopy 17 which forms a flooring for the storey above the platform. A motor-driven pump 6 draws liquid from a reservoir 5 and delivers to the ram cylinder to elevate the platform. By the operation of either of the levers 40, 42, Fig. 4, the lever 37 may be rotated to position the valve 10 to establish communication between the pump and cylinder for hoisting or between the cylinder and reservoir for gravity lowering. These two levers 40, 42 are interlocked so that in each case one must be separately released before the other can be operated, thus ensuring that the canopy is free before the platform is raised or lowered or vice versa. Fig. 2 shows the rectangular turntable 14 fitted with curved tracks 13 adapted to run between the rails 15 on the floors when the turntable is turned out of alignment with the lift well. Fig. 3 shows the electrical control. The motor 7 is in circuit with a relay 23, a switch 27 which is only closed when the platform is in alignment with the lift well, a stop push-button 25 and starting push-buttons 24 and 26 in the basement and on the ground floor respectively. In operation, the attendant on one floor presses one of the buttons 24 or 26. This rings a bell or signals in some way to the other floor. If the platform or canopy at the other floor is free, another attendant accepts the signal by pressing the other button. This double depression energizes the relay 23 and the latter closes the switches 21, 22 and 29. The motor then starts and the circuit is maintained when the push-buttons are released, through the lead 28. At the upper limit a ramp in the shaft opens the limit switch 31 and stops the motor. Should leakage occur in the cylinder, the falling cage closes the limit switch 33 and re-starts the motor to raise the platform again. The switch 35 is opened to cut out the limit switch 33, by the movement of the levers 40, 42 to permit lowering. At the limit of the downward movement the platform 4 engages the lever 37, Fig. 4, and resets the valve 10 to cut off direct communication between the cylinder and the reservoir. In addition it re-closes the switch 35. Fig. 5 shows the means for disconnecting the motor and using it to drive a belt pulley 47. A pair of interlocked clutches 46, 48 are operated by a lever 55 so that the pump 6 or pulley 47 are driven alternatively. To prevent the clutches from being operated to disconnect the motor from the pump, except when the lift is in its lowest position, a spring latch 59 engages between pins 60 on the clutch-operating rod 56. The platform 4 withdraws the latch by contact with the member 57 as it reaches its lowest position. The invention may be applied to a suspended lift cage.