Patent GB-1070176-A (GB)
Title: Automatic warehousing system
Inventor: DEBREY ROBERT JOHN
IPC: B65G1/04
Filed: 1966-03-29
Abstract: 1,070,176. Warehouse storing and dispensing systems. CONCO ENGINEERING WORKS Inc. March 29, 1966, No. 13850/66. Heading A4T. [Also in Division G3] In an automatic article warehousing system a stacker crane (23) (Fig. 1) travels in between two parallel racks of storage bins (21), a sensing means senses indicia identifying each vertical column of bins and a comparator compares each indicia read with an indicia stored in a memory. When the indicia read is the same as the stored indicia, a bi-directional motor (26) propelling the crane along an overhead rail (25) is slowed down and after a further short travel the motor is stopped by a switch (63) (Fig. 6) actuated by an abutment (61) on the overhead rail (25). The crane is now exactly positioned in front of the vertical column of bins identified by the stored indicia. A conventional fork lift (36) is mounted on a carriage (34) moved by a bi-directional motor (35) along a vertical column (30) on the crane and the movement of the carriage is controlled in the same way as the movement of the crane in response to indicia identifying each horizontal row of bins. The fork (36) is driven by a motor (37) and is inserted under an article supporting skid (39) in a bin, then raised by a small amount and then withdrawn. The fork can extend either to the right or to the left so that one crane can service the two racks of bins on opposite sides of the crane. The rows and columns of bins are identified by binary numbers, and the corresponding indicia are attached to the overhead rail (25), and to the vertical column (30) and are sensed by a horizontal sensing unit (48) and a vertical sensing unit (49). The digits of the binary numbers may be indicated by radioactive paint in which case the sensing units are radioactive energy detectors; or by projections detected by proximity switches; or by a perforated plate scanned by air jets, the holes being detected by a drop in supply pressure; or by small permanent magnets (55) (Figs. 4, 5) the digit one being represented by a magnet and zero by the absence of a magnet. The magnets may be mounted so that they are sensed sequentially by a top pick up (56) (Fig. 3) and the start of the number is identified by a small magnet 60 (Fig. 4) placed below the first and last digit of each number and sensed by a bottom pick up (57); alternately the magnets may be mounted so that they are read simultaneously by stacked pick up heads, (Fig. 5). The magnet numbers are located on the overhead rail at positions corresponding to the crane being at the start of each column of bins and the abutments (61) which stop the motor (26) propelling the crane are located at positions corresponding to the crane being at the centre of each column of bins. The control apparatus is housed in a unit (46) mounted on the crane and is shown in block diagram form in Fig. 7. When the crane is located at a home station, which is identified by a unique address, an information input unit 45 abuts a plurality of electrical input conductors 71 extending from a commands unit 70 fed manually or by computer. The information input unit 45 supplies a series of addresses, each comprising a vertical position binary number and a horizontal position binary number, to an address memory 72 and codes for storing or retrieving articles from each bin to a function memory 73. A signal from the information unit 45 activates a sequence control unit 75 which causes the address memory 72 to feed the horizontal address binary numbers of the home station and of the first bin to be serviced to a horizontal control unit 80, and the corresponding vertical address binary numbers to a vertical control unit 80<SP>1</SP> which is similar to the horizontal control unit 80. A direction control 82 determines the direction of the first bin from the home station and causes the motor 26 through a crane drive unit 85 to operate at high speed in either a forward or reverse direction. As the crane moves in a horizontal direction an indicia sensor 48 feeds sensed binary numbers on the overhead rail to a position comparator 86 which compares the sensed number with the number of the first bin if the crane is moving forwardly or compares the sensed number with the number of the first bin increased by one if the crane is moving in reverse. When the two binary numbers match, the comparator causes a drive control unit 90 to reduce the speed of the motor (26). The motor is stopped by the action of the next abutment (61) on the overhead rail and the fine position switch or sensor 63. When the sequence control receives signals from both the horizontal control 80 and the vertical control 80<SP>1</SP> indicating that the crane is correctly positioned at the desired bin it gates the function memory 73 and an instruction code is fed to a crane control 93. A cycle of operation of the fork 36 is carried out and the sequence control 75 then actuates the address memory 72 causing numbers indicating the present location of the crane and its next destination to be coupled to the horizontal and vertical controls 80, 80<SP>1</SP>. When the last operation stored in the memories 72, 73 is completed the sequence control gates the address of the home station to the controls 80, 80<SP>1</SP> and the crane returns thereto. The horizontal portion of the address memory 72 consists of five units 95 - - - 99, Fig. 8, each storing a binary number and each comprising a relay or flip flop for each digit of the number. A sequence programmer 101 produces an electric pulse to open a gate 103 to couple the number stored in the first memory unit 95 to a forward gate 110 and a reverse gate 111. The electric pulse is also fed to a compare address selector 113 which gates the current crane address and the address of the next location to the direction of travel circuit 114 which compares the two numbers and in consequence activates either an output 115 when the crane is to travel forward or an output 116 when the crane is to travel in reverse direction. The outputs 115, 116 are connected to the drive motor control circuit 118 and to the forward and reverse gates 110, 111 one of which therefore opens to couple the binary number from the first memory unit 95 to the comparator 120 which consists of a series of exclusive-OR circuits feeding a multiple input NOR gate. The comparator provides an output when a sensed binary number is the same as the binary number from the first memory unit and this output is fed to the drive control circuit 118 and to a gate 126 which opens to allow the fine position sensor to control the drive motor. When the crane is moved in reverse direction the binary number from the memory unit is increased by unity in an address translator 124 disposed between the reverse gate 111 and the comparator. The gate 126 and the corresponding gate of the vertical control unit 80<SP>1</SP> are connected to an AND gate 128 which actuates the sequence programmer 101 to cause the function memory 73 to feed the crane control 93. The direction of travel circuit is shown in Fig. 10. The most significant bits A 1  and A 2 , and their negated bits A 1  and A 2  are connected to four AND gates in pairs as shown. If an output A 1  A 2  is obtained, A 1  is present and A 2  is not and a reverse OR gate 140 is opened. If however As is present and A 1  is not an output A 1  A 2  opens a forward OR gate 141. If A 1  and A 2  have the same value then neither OR gate 140 or 141 is opened but instead one or other of the outputs A 1  A 2  and #A 1  #A 2  will be coupled through an OR gate 144 to AND gates 145, 146 which couple information from the second significant digit B to the forward and reverse OR gates 140, 141. The output A 1  A 2  and #A 1  #A 2  are also coupled to an AND gate 149 so that the third significant digit C can be examined if the B digits match. If all the digits of the two binary numbers are alike the sequence programmer is stepped to the next memory unit by an AND gate 50. The logic translator for adding one to each three bit binary number and reversing the order of the digits so that the desired number is read by the sensor when moving in reverse direction comprises AND gates and OR gates fed by the digits and their negations (Fig. 11, not shown).