Patent GB-1178603-A (GB)
Title: Storage Apparatus
IPC: B65G1/04
Filed: 1967-03-15
Abstract: 1,178,603. Storage systems; elevator control. CLARK EQUIPMENT CO. 15 March, 1967 [18 April, 1966], No. 12176/67. Headings B8E and B8L. [Also in Divisions G3 and G4] Storage apparatus comprises structures, including a structure 900, providing a plurality of storage bays disposed in columns and rows, a stacker 100 movable along aisles 1, 2 formed between the structures for servicing the storage bays, and a transfer cart 400 adapted to receive the stacker and transfer it between aisles, the transfer cart having a load support for carrying a storage unit independently of the stacker. The transfer cart, Fig. 3, is locked in position at the aisles by plungers which are operated pneumatically and engage fixed striker plates. It has extendible and retractable dollies for picking up a load, each being operated by a pneumatic ram which moves a shaft having gears engaging racks so that the associated dolly moves twice as fast as the ram. Each dolly has load pads having rollers to aid load movement, the load being on a pallet. When a dolly is retracted its pallet engages a guide rail which moves it laterally, and a second guide helps to position the pallet which comes to rest against a back stop. Two pivoted arms which are operated by pneumatic rams are used to position the pallet on each dolly, the pallet being pushed by the arms against the back stop and a comer guide bracket. Electrical circuits for controlling the automatic operation of the transfer cart are described with reference to Figs. 7, 8A, 8B, 8C and 9 (not shown). Included are reed switches operated by magnetic strips fastened to the structure at the ends of the aisles and used to control the destination of the cart. The circuits are interconnected with those for the stacker so that the cart and the stacker are automatically operated interdependently. A photo-electric cell and an associated lamp are provided to detect loads which are too high. A power supply (PS 400), see Fig. 9 (not shown), is connected through a control amplifier (931) to a summing amplifier (SA 400) to provide a " course " control circuit, the control amplifier being of the type in which a signal is amplified and may be adjusted so that its magnitude is changed. A " fine " control is provided by a transducer (LPT 401) which is also connected to the summing amplifier (SA 400) and senses the above said magnetic strips; the transducer is of the type that makes use of the " Hall Effect " in detecting magnetic material and is described in Specification 1,109,220. The output of the summing amplifier (SA 400) is connected to a driving amplifier (DA 400) which controls the excitation to a generator field (GF 400) of a generator (G 400) driving a motor M 400 which drives the cart. The motor M 400 drives a tachometer generator (TG 400) which is electrically connected to the summing amplifier (SA 400). The stacker 100, Fig. 10, has at its top a reed switch assembly 142 having wheels for engaging fixed locating rails to ensure proper alignment of the assembly as the stacker moves down the aisles. The switches of the assembly 142 are operated by magnetic strips disposed overhead in the aisles and identifying the storage bays. Upon a magnetic strip being detected by the corresponding switch the stacker is changed from a " course " mode of operation to a " fine " mode and the drive of the stacker is thereafter controlled by a transducer, similar to (LPT 401), which co-operates with magnetic strips one at each column of storage bays and on the transfer cart. A permanent magnet thereafter closes a further reed switch to stop the longitudinal movement of the stacker. The latter has an elevator 217 driven by a motor M 200 and having vertically extending magnetic strips which co-operate with reed switches to indicate the vertical alignment of the elevator with the rows of storage bays and change the elevator control to a " fine " mode of operation. A " superfine " mode of operation is thereafter provided and the elevator is stopped by permanent magnets. A transducer is secured to a shifter bar which is movable vertically through a limited distance by a motor to cause the motor M 200 to move the elevator the same limited vertical distance but in the opposite direction for depositing or retrieving a pallet. There are obstruction-sensing devices on the elevator. The elevator has a platform 386 which is driven by a motor to extend to either side of the elevator, the motor driving a member carrying gears which engage racks on the elevator and on the platform. The latter moves twice as fast as the motor-driven member. Electrical interlocks between the transfer cart 400 and the stacker 100 are described with reference to Figs. 24A, 24B (not shown). Electrical circuits for controlling the automatic operation of the stacker are described with reference to Figs. 21A ... 21H and 22A, 22B (not shown). The longitudinal driving circuit comprises a summing amplifier (SA 100), see Fig. 22A (not shown), which has connected to it a transducer (LPT 102) to provide the " fine " mode of operation. The summing amplifier (SA 100) is connected to a driving amplifier (DA 100) which is connected to a field coil (GF 100) of a generator (G- 100) driving the longitudinal drive motor (M 100) and the lateral drive motor (M 300). The motor (M 100) drives a tachometer generator (TG 100) which is electrically connected to the summing amplifier (SA 100). In the " course " mode of operation a power supply (PS 100), see Fig. 22B (not shown), is connected to the summing amplifier (SA 100) through a potentiometer (P 101), relay contacts (CR 10) being provided to determine the direction of drive. The lateral driving circuit does not use a " course " mode of operation but uses only a " fine " mode which is accomplished by connecting the power supply (PS 100) to a summing amplifier (SA 300) which is connected to the driving amplifier (DA 100). It should be noted that the longitudinal drive motor (M 100) is never operated while the lateral drive motor (M 300) is operated. The direction of the latter is determined by relay contacts (CR 12) and it drives a tachometer generator (TG 300) which is connected through a potentiometer (P 301) to the summing amplifier (SA 300). The latter has also connected to it a linear voltage differential transformer (LVDT 301) the output voltage of which varies with the lateral position of the platform (386). The vertical driving circuit is divided into the " course " control, the " fine " control and the "superfine" control. The "course" control is provided by connecting the power supply (PS 100) through a potentiometer (P 201) to a summing amplifier (SA200), the direciion oftravel being determined by relay contacts (CR6 and CR7). The summing amplifier (SA 200) is connected to a driving amplifier (DA 200) which is connected to a generator field (GF 200) of a generator (G 200) driving the motor (M 200). The latter drives a tachometer generator (TG 200) which is electrically connected to the summing amplifier (SA 200). The " fine " control is provided by connecting the transducer (LPT 203) through a summing amplifier (SA 201) to the summing amplifier (SA 200). The " superfine " control is provided by connecting the transducer (LPT 203) through an integrating amplifier (IA 201) to the summing amplifier (SA 200). Transfer cart and stacker operation.-An example is given in which a load is deposited on one of the dollies, the stacker 100. is transferred from aisle 1 to aisle 2 and the load deposited in a predetermined storage bay. With the stacker on the transfer cart and its elevator platform centred it permits movement of the dolly which is extended to receive the load. The dolly is then retracted; if the load is too high its movement is stopped. When it is fully retracted the load is positioned correctly on the dolly. The transfer cart is next moved to aisle 2 and the stacker is then permitted to pick up the load and deposit it in the predetermined storage bay. The stacker is then directed to a second storage bay in aisle 2 to pick up a load therefrom and deposit it on one of the dollies of the transfer cart and this second load movement is automatically carried out after the first load movement. A safety circuit is provided, Fig. 21F (not shown), to ensure that the stacker is not driven towards the transfer cart in the "course" mode of operation with the elevator above the level of the second lowest row of storage bays at a time when the stacker is between the transfer cart and the third nearest column of storage bays. An electrical servo-loop may be used to operate and control the destination and speed of the transfer cart and means may be provided for sensing an obstruction in the path of the transfer cart or the stacker and for stopping the apparatus.