Movable storage unit system

A movable storage unit system comprising a plurality of individually driven storage units at least some of which are movable toward and away from one another into contact with one another to define an access space between a pair of the units. A logic control circuit is provided on each unit and a limit sensor is provided on each movable unit including a sensor circuit for creating a signal in response to contact of a pair of storage units. A safety sensor is also provided on each unit and includes a safety sensor control circuit for creating a signal upon engagement of the safety sensor and an object or person in the path of the unit. A pair of reset controls is provided on each unit including a reset control circuit for creating a logic signal when actuated, and a run control is provided on each unit for creating a logic signal when actuated. The storage units are electrically connected such that a logic signal from the run control directs a run signal to a next adjacent unit. Each logic module includes a pair of reset transmit circuits for producing reset output signals, the reset transmit circuits of the logic modules being electrically interconnected. Each logic module includes a command inhibit circuit for receiving a run signal and electrically connected to receive signals from the reset control circuits, safety control circuit, and limit control circuit of its respective storage unit to inhibit the transmittal of the run signal. Each logic module includes a pair of move transmit circuits for producing move signals, the move transmit circuits of adjacent storage units being interconnected. Each logic module includes a move steering logic circuit for producing move command signals, the move command signal actuates a drive unit of a respective storage unit in one direction or the other.

This invention relates to a movable storage unit system and particularly to 
controlling the motion of storage units arranged in contact proximity with 
one another and selecting a space between any two of the units. 
BACKGROUND AND SUMMARY OF THE INVENTION 
It is common to provide storage units which are movable by power into 
contact with one another and can be selectively separated to form an 
access space. The units may be any device arranged in linear, circular, 
horizontal, vertical, or any other fashion where sequential order is 
maintained. The units may be file cabinets, trays, lockers, carriages, 
platforms, book storage units, freezer lockers, refrigerated units, 
furniture storage units, tape storage units, or any other device intended 
for storing, filing, preserving, protecting, accumulating and the like. 
The purpose of maintaining contact proximity is to reduce the amount of 
area, distance, floor space or other volume required for storage. The 
purpose of selecting a space between any two of the storage units is to 
gain access to a desired storage location. 
While the concept of controlling storage units as described above is not 
new, and numerous methods have been employed in the past, the present 
invention is directed to a control system which uses standard control 
functions in each unit, without the necessity for central control, 
computing, or monitoring, thus saving in control hardware, and eliminating 
the need for different assemblies at different locations. The control 
system can be designed with a standard control device for each of the 
units, including those which are placed at the end of the sequence. This 
reduces different replacement control devices to one type with concimitant 
savings in stock cost and control and simpler maintenance techniques and 
routines. 
In addition, the control system provides for safety controls that require 
the operator to perform reset functions before operation thereof; wherein 
once reset, the system must be operated during a predetermined period of 
time; wherein if operation is discontinued, the operator must perform a 
reset function; wherein the controls for operation are oriented the same 
on each storage unit; and wherein there is a redundant safety system 
deactivating the solid state logic as well as the mechanical relay 
control.

DESCRIPTION 
Referring to FIG. 1, the movable storage unit system embodying the 
invention is herein shown as applied to book storage units. However, the 
system is also applicable to any powered storage units arranged in linear, 
circular, horizontal, vertical, or any other fashion where sequential 
order is maintained. The units may be file cabinets, trays, lockers, 
carriages, platforms, book storage units, freezer lockers, refrigerated 
units, furniture storage units, tape storage units, or any other device 
intended for storing, filing, preserving, protecting, accumulating, and 
the like. 
As shown, the system includes storage units 10 movable by motors 11 along a 
track 12. Each motor 11 includes a drive wheel 13 that engages the floor 
to drive the unit. Such an arrangement is well known as shown, for 
example, in U.S. Pat. Nos. 3,615,122 and 3,856,446. 
Each storage unit 10 includes identical controls and indicators at each end 
thereof. More specifically, each movable storage unit includes at each end 
two reset buttons 15 and a run control button 16. Visual signals 17, 18, 
19 are also provided at each end. As presently described, in any array of 
storage units, some of the control buttons are eliminated in the endmost 
storage units which are stationary. 
In addition, each storage unit includes a sensor in the form of a limit bar 
20 along each side thereof which operates a limit switch 21 when one 
storage unit engages another. Furthermore, each storage unit 10 includes a 
safety sensor in the form of a safety bar 22 extending along each side 
thereof which is actuated by any object or person in the aisle if a unit 
10 is driven toward the object or person. It should be understood that 
sensors 20, 22 are shown as mechanically operated switches, but other 
well-known sensors can be used such as optical, acoustical, or magnetic 
sensors. 
The manner in which the control system functions to control and operate the 
storage units can be understood by reference to FIGS. 3 and 4. 
FIG. 3 is a simplified diagram for east motion and FIG. 4 is a diagram for 
west motion. Any number of additional units may be placed on either or 
both ends outside of the units shown. The geographical directions are for 
reference and discussion purposes only. 
Assume that east motion is desired (FIG. 3). An operator approaches the 
storage units from the south. A desired space is shown west of an open 
space. The number of places the desired space is from the open space can 
be any value, depending on the installation. The system is designed such 
that the operator always uses a Run control device to his right, in this 
case Run (N). 
The operator first approaches the open space to observe that it is free of 
obstructions or personnel. He then causes a reset of the control circuitry 
by activating reset control devices simultaneously on each side of the 
open space, Reset W (N-1) and Reset E (N). 
Optical indicators 18, 19 show that the system is in either a deactivated 
or in a run condition. In the deactivated condition, a system reset must 
be performed. In a run condition, motion must be caused before time out of 
the system reset circuit. 
After activating the system by performing a reset, the operator then moves 
to the desired space. He activates the Run control to the right of the 
desired space, Run (N) on unit N. The units to his right then move to the 
east, filling the open space, until the desired space is available. The 
motion is stopped by the moving units coming into contact with the 
stationary units to the east. Sensors exist on both the moving and 
stationary units to cause motion to cease when the units are on contact 
with one another, Limit W (N-1) and Limit E (N). 
Similar sequence of operations holds for an operator approaching the system 
from the north. He activates the system by pushing both Reset controls. 
Reset W (N-1) and Reset E (N). He then moves to the desired space where he 
depresses the Run button on his right, Run on the (N+1) storage unit. This 
causes the storage unit or units to move to the east, filling the open 
space. 
Similar action prevails for west motion (FIG. 4). If the safety sensors 22 
are activated, all motion stops and is prohibited until the system Reset 
controls are again activated. 
As presently described, each storage unit includes a storage unit logic 
module 25 having signal lines as indicated in FIG. 6. The logic modules in 
adjacent storage units 10 are interconnected by signal lines as shown in 
FIG. 5. 
Each logic module 25 can be represented by the block diagram shown in FIG. 
7. When the reset buttons 15 are depressed, a logic signal is provided 
which sends a signal to the reset transmit modules 26, 27 and, in turn, to 
adjacent modules 25. In addition, the reset signal passes to a command 
inhibit module 28. The module 28 functions to inhibit a move signal in the 
event a safety signal is received from the safety sensor 22 or a limit 
signal is received from a limit sensor 20. In addition, module 28 
functions to inhibit a move signal after a predetermined time delay. 
When a run signal is received by activation of run button 16 of the 
adjacent module 25, a run signal is transmitted through the move modules 
29, 30. Each storage unit is successively operated by move steering logic 
module 31 which transmits a move command signal. 
Each module 25 is shown more specifically in FIG. 8 wherein all input 
signals are active as indicated on the drawing, all output signals are 
active low, and all bus signals are active low. 
Initially, the following conditions exist: 
1. Power-up on Inhibit Time Delay A6 produces low output through NAND gate 
A3A forcing Q low on flipflop A5A and Q low on flip-flops A11A and A11B. 
2. Q low from flip-flop A5A forces high outputs from NAND gates A8A, A8B, 
A9A and A9B, which produces high outputs through NAND gates A12C and A12D 
on the Move Transmit Bus. 
3. Q low from flip-flop A5A produces low inputs through NAND gate A10A and 
A10B to NAND gates A8D and A9D to force their outputs high. The low levels 
from AND gates A10A and A10B are inverted by inverters A7C and A7D to 
produce a high output from AND gate A3C. 
4. Q low from flip-flop A5A also produces low inputs to logic resets on 
flip-flops A4A and A4B causing thier Q outputs to be high, deactivating 
move command through A8C and A9C. 
5. Q high from flip-flops A11B and A11A produces high D input to the 
opposite half of the flip-flop pair, which are in a cross-coupled 
arrangement. 
6. Q high from flip-flop A5A inhibits activation of the movable pilot 
light. 
Accordingly, since all move outputs are logic high, motion is inhibited. 
Assume east motion is desired as shown in FIG. 3. The operator moves to 
open aisle and pushes Reset buttons, Reset E on storage unit N and Reset W 
on storage unit N-1. This causes high inputs to NAND gate A1A. NAND gate 
A1A output will go low only if Limit West (N-1) and Limit East (N) are 
both high for an open aisle. The purpose of this is to force Reset to an 
open aisle. Low output from NAND gate A1A produces low through A2A and A2C 
to make outputs on Reset Transmit Bus low through NAND gates A12A and 
A12B. 
At the same time a low output occurs from AND gates A10C to trigger inhibit 
time delay A6. Inhibit time delay A6 produces a high output through NAND 
gate A3A to remove logic set on flip-flop A5A and logic reset on flip-flop 
A11. However, this occurs only if the safety bus is high, not activated, 
to gate A3A to an ON condition. The high output from A3A is inverted by 
inverter A7F through a differentiator to reset flip-flop A5A which 
produces a high output on Q to open the move transmit buses, the move 
outputs, and to release the run latches A4A and A4B. 
The inhibit time delay A6 is used to time-out the control circuitry and 
force initial conditions a specified period of time after the reset 
buttons 15 are depressed, adjustable, for example, to 30 seconds or more. 
This forces an operator to initiate motion during the time-out period, and 
prohibits another operator from activating the motion controls if the 
first operator leaves the ranges with incomplete motion status. After the 
time-out period, the inhibit time delay A6 output will go low, inhibiting 
all motion. 
Reset signals coming into the unit from other units will produce the same 
action as the local reset button. 
To produce motion after depressing the reset buttons at the aisle, the 
operator moves to the west of the open aisle. In this case, the next 
immediate aisle is illustrated (FIG. 3). The operator pushes the run 
button 16 on the right of the desired aisle. A low to "Set" input on run 
latch A4B causes Q output low to gate A9C to force a high on gate A9B. 
Since the other input to NAND gate A9B is also high, the output goes low. 
The low is transmitted through A12D onto the move transmit bus. The run 
latch A4B holds the move command active until reset. 
The high from A9C causes a high from A10B which clocks A11B Q output high 
and gates A9D to cause a low move east signal. 
A similar sequence is transmitted through A12C onto the move transmit bus 
in the opposite direction except that it bypasses gate A8C and is 
transmitted through gate A8A via inverter A7A. The output of A7D also goes 
low to cause a low move signal through gate A3C. The high signal through 
gate A10B is active only if the limit east is high for an open aisle 
condition. If not, the move east and move signals are blocked. When the 
unit reaches its limit of motion against the unit next in line the limit 
east closes, inhibiting motion. At the same time, the low limit east 
signal produces a high output through gate A3B via inverter A7E to clock 
flip-flop A5A into a Q low output inhibiting the move transmit bus and 
preventing a move signal from passing through the unit from other units. 
The Q low output from flip-flop A5A also resets the run latch A4B. 
If the move command comes from a unit further to the west, move east will 
be initiated only after limit east goes high when a preceding unit clears 
the limit sensor 20. 
In this manner, motion can take place only in the direction of an open 
aisle, when the preceding aisle opens, and will cease if the aisle closes. 
West motion works in an identical manner (FIG. 3). 
North run buttons work in a similar manner, except they are removed by one 
unit away to achieve control through the run button to the right of the 
desired aisle. 
Operation of the safety bus, either locally or from other units, will 
always force low signals through gate A3A to set flip-flop A5 and 
flip-flop A11, inhibiting all motion. 
If any aisle is open, transmission of the reset signals through the reset 
transmit bus is blocked by a high on A2B and A2D. This forces an operator 
to reset all open aisles individually that may exist due to discontinued 
motion of a move operation. The run signals bypass through gates A8A and 
A9A in order to obtain proper direction sensing for run buttons located to 
the righ of the desired aisle. 
When a limit opens, as the preceding unit moves away, it permits run 
signals to activate the proper move outputs for that unit, even though 
coming from some other unit down the line. 
Run command is sensed on the move transmit bus in both directions, but the 
sequence of unit motion permits the commands to function only in one 
direction. A run command will cause motion only for those units between 
the command source and an open aisle. 
If aisles are open to both the east and the west (an unusual condition), 
and if all resets have been activated properly, all units to the east of 
the run command will move to the east, and all units to the west of the 
run command will move to the west. In this manner, motion will always by 
away from an operator and will create a proper open aisle. 
FIG. 9 shows the manner in which the logic and motor controls are 
interconnected, while FIG. 10 shows the relay circuit for controlling the 
direction of movement of the motor. The contacts of safety sensor switches 
22 are in series with relay CR1. The contacts of relay CR2 are in series 
with the contacts ME + MW of motor relays ME and MW (controlling east and 
west operation). 
Thus, mechanical interlocks are provided through relay contacts. Safety 
sense switches must all be closed. Any open safety switch 20 will 
deactivate power to relay CR1, as well as cause a reset to the logic. 
Relay CR1 open will open relay CR2 and hence power to the drive motor. 
Therefore, two events will inhibit motion: Relay CR2 will be open and the 
move signal from the logic will be inactive. 
Relay CR1 has a latch contact which holds it closed after it is set by the 
control reset from the logic. 
The move east and move west relay contacts are arranged in such a manner 
that if neither are active AC power to the drive motor is off. If both are 
active, power to the motor is off. Only if either one, but not both, are 
active will power be applied to the drive motor. 
These features are intended to provide redundancy on safety, such that 
failure in any one component will not activate the drive. 
The control logic described above can be mounted in any convenient location 
on the storage unit. Only one control circuit is required per storage 
unit, but necessary switches or elements for activating and guiding the 
storage unit must be located according to the physical arrangement. 
Power for the control devices may be derived from the power feed supplying 
drive motors or other driving devices. 
FIG. 11 is a typical optical isolator input circuit associated with limit 
sensors 20 or reset buttons 15 to produce a signal to the logic and 
includes a limit sensor 35, a current limiting resistor 36, and an optical 
coupler diode 37 in series. 
FIG. 12 is a typical circuit associated with safety sensors 22 to produce a 
signal through the optical isolator input to the logic and to deactivate 
CR1 and comprises a current limiting resistor 38 and an optical coupler 
diode in parallel with relay CR1.