U.S. patent number 3,786,929 [Application Number 05/194,713] was granted by the patent office on 1974-01-22 for warehousing system using slowdown and stop bin indicators.
This patent grant is currently assigned to Conco Inc.. Invention is credited to James S. Hathcock, Jr..
United States Patent |
3,786,929 |
Hathcock, Jr. |
January 22, 1974 |
WAREHOUSING SYSTEM USING SLOWDOWN AND STOP BIN INDICATORS
Abstract
To identify vertical slowdown and stop positions for a stacker
crane, each vertical bin is uniquely located by a binary coded
slowdown plate and a separate binary coded stop plate. A vertical
drive control is responsive to photoelectric sensors, mounted on a
crane hoist, as the sensors are driven adjacent the binary coded
plates. To reduce the minimum vertical spacing between bins, the
coded plates are interleaved so that the slowdown plate for an
adjacent bin is located between each stop plate and slowdown plate
for a different bin. Various combinations of detectable elements
are carried on each coded plate to provide strobe, high or deposit,
and low or retrieve information.
Inventors: |
Hathcock, Jr.; James S.
(Houston, TX) |
Assignee: |
Conco Inc. (Mendota,
IL)
|
Family
ID: |
22718641 |
Appl.
No.: |
05/194,713 |
Filed: |
November 1, 1971 |
Current U.S.
Class: |
414/273; 187/291;
414/281; 246/25 |
Current CPC
Class: |
B65G
1/0421 (20130101) |
Current International
Class: |
B65G
1/04 (20060101); B66g 001/36 () |
Field of
Search: |
;214/16.4A ;187/29R
;246/2S |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Forlenza; Gerald M.
Assistant Examiner: Libman; George H.
Attorney, Agent or Firm: Hofgren, Wegner, Allen, Stellman
& McCord
Claims
I claim:
1. In a warehousing system having a plurality of load storing
means, rail means extending along and fixed with respect to said
load storing means, carriage means movable along said rail means
and including load carrier means for depositing and retrieving
loads from adjacent load storing means, and drive means for moving
said carriage means including drive slowdown means actuable to
decrease the speed of said carriage means in anticipation of
reaching a selected load storing means and drive stop means
actuable to stop said carriage means at the selected load storing
means, the improvement comprising:
a plurality of separate address means mountable at different spaced
locations on said rail means for uniquely identifying slowdown and
stop positions for each of said load storing means, each separate
address means including coded slowdown indicating elements for
identifying the slowdown position at which said drive slowdown
means should be actuated and coded stop indicating elements
separate and spaced from said slowdown indicating means for
identifying the stop position at which the drive stop means should
be actuated when the load carrier means is to service the load
storing means associated therewith, each separate address means
further including control elements for modifying the operation of
the drive means for the same address as identified by the
indicating elements;
interleave means for mounting said separate address means at
desired spaced locations along said rail means with at least one of
said coded slowdown indicating means being mounted to said rail
means at a location between the coded slowdown indicating means and
the coded stop indicating means for a different load storing
means;
plural sensor means mounted to said carriage means and movable
adjacent said rail means for detecting said indicating elements and
said control elements;
control means responsive to detection of the coded slowdown and
coded stop indicating elements in conjunction with the control
elements associated with the selected load storing means for
actuating the drive slowdown means and the drive stop means,
respectively.
2. The improvement of claim 1 wherein each coded slowdown
indicating element carries a plurality of detectable indicia which
uniquely identifies the load storing means associated therewith and
each of said coded stop indicating elements carries a plurality of
detectable indicia which uniquely identifies the load storing means
associated therewith, one of said plural sensor means detecting
said detectable indicia for transmission to said control means.
3. The improvement of claim 2 wherein each of said address means
carries a binary code for uniquely identifying the slowdown and
stop positions of the associated load storing means, and the
detectable indicia on the slowdown indicating element and the stop
indicating element for the same load storing means comprises
identical binary bits defining said binary code.
4. The improvement of claim 3 wherein said control means includes
selective address means for storing a binary code of a selected
load storing means, match means having inputs coupled to said
sensor means and said selected address means and actuated when a
match has occurred, slowdown relay means actuated each time the
sensor means detects one of said slowdown indicating elements, stop
relay means actuated each time said sensor elements detects one of
said stop indicating means, slowdown circuit means responsive to
actuation of said match means and said slowdown relay means for
actuating said drive slowdown means, and stop circuit means
responsive to actuation of said match means and said stop relay
means for actuating said drive stop means.
5. The improvement of claim 1 for a warehousing system in which the
drive means is bidirectional for moving said carriage means in
opposed directions adjacent the load storing means, wherein said
coded slowdown indicating element comprises first and second coded
slowdown members spaced on opposed sides of the associated coded
stop indicating element for the same load storing means.
6. The improvement of claim 5 wherein said first coded slowdown
member defines a slowdown position located in one direction
preceding the associated coded stop indicating element and said
second coded slowdown member defines a slowdown position located in
an opposed direction preceding the associated coded stop indicating
element, and said interleaving means mounts the first coded
slowdown member for an adjacent load storing means between the
second coded slowdown member and the coded stop indicating element
for the same load storing means.
7. The improvement of claim 5 wherein each of said coded slowdown
members carries an identical plurality of detectable indicia which
define the same unique number.
8. The improvement of claim 7 wherein each coded stop indicating
element carries a plurality of detectable indicia identical to the
plurality of detectable indicia on the associated pair of coded
slowdown members.
9. The improvement of claim 1 wherein at least one of said coded
indicating elements for each address means carries a plurality of
detectable binary bits which identify a unique binary number
associated with only that coded address means, each coded stop
indicating element includes at least one strobe element for
indicating when information detected by said plural sensor means is
valid, each coded slowdown indicating element carries at least one
strobe element for indicating when information detected by said
plural sensor means is valid, said plural sensor means includes at
least binary bit detector means for detecting said binary bit
elements and strobe means for detecting said strobe elements, and
said control means being enabled only when said strobe means
indicates that valid information is present.
10. The improvement of claim 9 wherein each coded stop indicating
element includes at least two strobe elements corresponding to said
control element, and said control means includes safety means
responsive to selected combinations of detected strobe elements on
said coded stop indicating element for indicating that the carriage
means is positioned within a predetermined stop zone.
11. The warehousing system of claim 1 in which the plurality of
load storing means comprises horizontally spaced and vertically
stacked bins, said carriage means comprises a stacker crane having
hoist means vertically movable adjacent the vertically stacked bins
for depositing and retrieving loads therefrom, said drive means
includes vertical drive means for vertically propelling said hoist
means in upper and lower directions for servicing the vertically
stacked bins, vertical drive slowdown means actuable to decrease
the vertical speed of propulsion of said hoist means and vertical
drive stop means for precisely stopping the hoist means at a
selected bin, each of said control elements includes a high
position element and a low position element for identifying high
and low vertical positions, respectively, for each vertically
stacked bin, said plural sensor means includes address detector
means for detecting the unique address associated with each address
means and control element detector means for detecting said control
elements, and said control means includes deposit circuit means
responsive to detection of the stop indicating element having a
selected unique address and the high position element for actuating
said vertical drive stop means and retrieve circuit means
responsive to detection of the stop indicating element having a
selected unique address and the low position element for actuating
said vertical drive stop means.
12. The improvement of claim 11 wherein each coded stop indicating
element carries a pair of identical binary bit means located at
positions corresponding to said high and low vertical positions,
and said high and low position elements comprise strobe indicators
aligned with the pair of binary bit means.
13. The improvement of claim 1 wherein each of said coded
indicating elements and each of said control elements includes a
plurality of areas which each either pass or block a photobeam to
indicate the state of a bit, and said plural sensor means comprises
light source means generating photobeams directed at a spaced
photocell means and mounting means for locating said photobeams in
a path which passes through the areas of said coded indicating
elements and said control elements in order to detect said bits.
Description
BACKGROUND OF THE INVENTION
This invention relates to a warehousing system which uses separate
slowdown and stop bin indicators.
Many warehousing systems uniquely identify horizontal bin position
by mounting binary coded address plates to a storage framework, and
identify vertical bin position by mounting binary coded address
plates to a column of a stacker crane. Each address plate is
aligned to correspond with the position of the bin associated
therewith. To identify vertical slowdown and stop positions for
each stacked bin, it has been conventional to provide a unitary,
vertically elongated cam plate having a plurality of cam surfaces
extending between lower and upper slowdown positions. The lower
slowdown position is used to decrease the speed of the crane hoist
when approaching a selected bin from a lower vertical level.
Conversely, the upper slowdown position is used to decrease the
speed of the crane hoist when approaching a selected bin from a
higher vertical level.
In addition to upper and lower slowdown cams, the elongated cam
plates have included further cams for identifying the high and low
stop positions for the hoist. When initiating a deposit or a
retrieve cycle, the forks on the crane hoist must initially be
stopped at the high or low stop positions, respectively.
In order to stack a greater number of bins in a given vertical
height, the unitary binary code plates have been spaced closer
together. The minimum spacing required between adjacent bins,
however, has heretofore been limited by the height of the unitary
vertical code plates. In a high speed system in which the slowdown
position must substantially precede the stop position, the minimum
vertical spacing between bins has therefore been severely
limited.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved bin
indicating system substantially reduces the minimum spacing
necessary between adjacent bins. The system is equally applicable
to uniquely identify slowdown and stop positions for bins spaced in
a horizontal and/or vertical direction in a storage framework. This
is accomplished by providing separate slowdown and stop bin
indicators which are interleaved throughout the length of the bin
framework. Preferably, each indicator is binary coded, and contains
additional elements for identifying other information useful in
decoding and controlling the crane drive mechanism.
A principle object of this invention is the provision of a
warehousing system using interleaved slowdown and stop bin
indicators in order to allow complete versatility in spacing and
arranging bins.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and features of the invention will be apparent
from the following description, and from the drawings, in
which:
FIG. 1 is a perspective elevational view of a warehouse with a
stacker crane, in which vertical bin positions are identified by
use of the applicant's invention;
FIG. 2 is a plane elevational view of a plurality of bin
identifying plates, attached to one vertical column of the stacker
crane shown in FIG. 1, and detected by a photocell sensor unit
which is mounted to the carriage hoist shown in FIG. 1; and
FIG. 3 is a schematic diagram of a drive control circuit which, in
response to the photocell sensor unit in FIG. 2, controls the
vertical speed of traverse of the crane hoist.
DESCRIPTION OF THE PREFERRED EMBODIMENT
While an illustrative embodiment of the invention is shown in the
drawings and will be described in detail herein, the invention is
susceptible of embodiment in many different forms and it should be
understood that the present disclosure is to be considered as an
exemplification of the principles of the invention and is not
intended to limit the invention to the embodiment illustrated.
FIG. 1 illustrates a warehousing system embodying the invention. A
storage rack 20 contains a plurality of individual bins 21 or other
load supporting means for holding articles therein. The bins 21
extend horizontally along a row and are vertically stacked to any
desired height. A load conveyor or article handling device, such as
a stacker crane 23, travels in an aisle or other travel zone
adjacent the row of storage bins 21. The stacker crane 23 is guided
in a horizontal direction between an overhead horizontal guide or
support rail 25 and a floor mounted horizontal drive rail 26. A
horizontal crane carriage 30 is driven along the floor rail 26 by a
conventional drive mechanism (not illustrated) which moves the
stacker crane 23 in either a forward or reverse direction adjacent
the bins 21.
A vertical mast structure extends upward from the horizontal
carriage 30 and includes a pair of spaced columns 32 and 33 which
are rigidly tied together through an upper carriage frame 35. The
frame 35 mounts a conventional hoist mechanism which is driven by a
hoist motor and brake apparatus 37. The hoist mechanism may, for
example, take the form of a pair of chain belts, wound on a hoist
shaft which is rotated by the motor 37, which connect to a vertical
hoist carriage 40 which is thereby vertically propelled between the
spaced columns 32 and 33.
Mounted on the vertical hoist carriage 40 is a conventional fork
mechanism 42 which can be horizontally propelled into an adjacent
bin 21 in order to deposit or retrieve a pallet on which the load
may be deposited. Typically, another storage framework (not
illustrated) is spaced from the illustrated framework, with the
crane 23 being driven along a narrow aisle therebetween. In such
installations, the fork mechanism 42 could be selectively
horizontally propelled to either the right or left in order to
service both storage frameworks.
The stacker crane 23 may be operated automatically under control of
externally generated signals, or manually by an operator standing
in an operator's cab 45 and actuating control switches on an
operator panel (not illustrated). Many other conventional
structural and control elements omitted for clarity, may be
provided as desired.
In order to identify the vertical position of each bin 21, a unique
address plate 50 is mounted to a vertically extending rail 52 which
is secured relative to and spaced from one vertical column of the
stacker crane, herein column 33. The rail 52 is spaced from column
33 in order to define an opening therebetween for passage of a
light source 54 attached to carriage 40. A photocell sensor unit
55, similarly mounted to the vertical carriage 40, is spaced on the
opposite side of the rail 52 and aligned to intercept photobeams
generated by the light source 54. As the hoist is vertically driven
by the motor and brake mechanism 37, the light source 54 and
photocells 55 move pass each code plate mounted on the address rail
52 in order to detect the vertical position of the carriage 40.
In a high speed system, it is necessary to provide slowdown
indicators which indicate when the motor 37 should be controlled to
produce a slow speed of traverse in anticipation of reaching a
desired vertical level. For this purpose, a high slowdown indicator
60 is spaced vertically above the address plate 50 to indicate the
slowdown point when the carriage 40 is being driven downwardly. A
similar low slowdown indicator 62 is spaced vertically beneath the
code plate 50 to indicate the slowdown point when the carriage 40
is located below the desired bin and is being driven upwardly. For
clarity, the code plate 50 and its associated slowdown plates 60
and 62 for only a single bin have been illustrated in FIG. 1, it
being appreciated that similar indicators are provided for all
vertical bins 21. The exact form of the indicators 50, 60 and 62 is
illustrated in detail in FIG. 2 for several bins.
Turning to FIG. 2, a portion of the address plates associated with
three vertical bins, arbitrarily identified by decimal numbers 2, 3
and 4, have been illustrated. All stop indicators 50, upper
slowdown indicators 60, and lower slowdown indicators 62 have been
identified by the same reference numeral, followed by a number
which indicates the bin identified by that indicator. For example,
the stop address plate for bin 3 is identified as 50-3. Each
vertical bin level is assigned a unique address, preferably a
binary number formed from a combination of indicia. The binary
number is illustratively comprised of six binary digits or
bits.
The presence or absence of a bit can be indicated by any type of on
or off, 0 or 1 indicating element, and herein comprises the
presence or absence of a light passageway or opening in the plates.
Arbitrarily, the presence of an opening represents a 1 bit and is
illustrated by a solid line 70. Similarly, the absence of a
passageway represents a 0 bit and is illustrated by a dashed line
72 adjacent the area through which the photobeam would otherwise
pass. Thus, plates 50-2 and 60-2 associated with bin 2 carry the
binary code 000010, the plates 50-3, 60-3 and 62-3 associated with
bin 3 carry the binary code 000011, while the plates 50-4 and 62-4
associated with bin 4 carry the binary code .00100.
In accordance with the present invention, the slowdown address
plates 60 and 62 are separate from the stop address plates 50. Any
one or more of the slowdown indicators 60 and/or 62 may be
interleaved between the indicators for other bins. In the
illustration, slowdown indicator 60-2 has been interleaved or
placed between the stop indicator 50-3 and the lower slowdown
indicators 62-3. Similarly, lower slowdown indicator 62-4 has been
interleaved between the stop indicator 50-3 and the upper slowdown
indicator 60-3. While the slowdown indicators of adjacent bins have
been interleaved, it will be appreciated that the indicators could
be further spaced apart, as might be advantageous in a very high
speed system.
Considering the bin indicators in detail, each stop address plate
50 carries a pair of identical binary codes, located at the high
and low stop position for the vertical carriage. When the vertical
carriage is to deposit a load, the forks must be stopped at a high
position to allow the forks to be extended with a skid located
thereon. After the forks are extended, the vertical carriage moves
downward to the low stop position to allow the forks to be
withdrawn. Conversely, when a retrieve operation is being
performed, the vertical carriage is first stopped at the position
of the lower binary codes, and after extending the fork, is driven
vertically upward to the position of the upper binary code before
retracting in order to retrieve a skid.
Each stop plate 50 further includes a plurality of tabs or surfaces
to provide gating and other information. A high position strobe tab
is located between an upper surface 90 aligned with the upper
binary code and a lower surface 92 aligned with the lower binary
code. A low position strobe tab extends between surfaces 94 and 96.
The tab surface 96 extends inward for a limited distance, and then
vertically rises to an upper surface 98 which is vertically level
with surface 90. The area between surfaces 90 (or 98) and 96 forms
a strobe or trigger area 100 for the upper binary code, and the
area between surfaces 92 and 94 forms a low binary code strobe or
trigger area 102. The stop address plate 50 may be attached to the
vertical rail 52 of FIG. 1 by screws extending through a pair of
openings 106 located in the center of the plates.
The pair of slowdown plates 60 and 62 for the same bin are of
identical construction. A pair of openings 110 allows each slowdown
plate to be attached to the vertical rail 52 at any desired
vertical level. Only a single binary code is carried on each plate,
since it is sufficient to provide only one advance slowdown
position regardless of whether the vertical carriage will be
stopped at a high or low position. Of course, separate binary codes
for the high and low stop positions could be provided, if so
desired. A strobe or triggering area is defined by an upper tab
surface 112 and a lower tab surface 114, which surfaces are
vertically aligned with the tab surfaces 98 on stop plates 50.
Photocell sensor unit 55 contains a plurality of individual
photocells 120 horizontally spaced to detect the various
information carried on plates 50, 60, and 62. As viewed from left
to right in FIG. 2, the first photocell 120 is a top limit
indicator which detects a special safety plate (not illustrated)
which is located at the highest vertical position for the carriage
40. This photocell is connected to override any up vertical
command. The next photocell 120, labeled A, is positioned to detect
the stop plate tab located between surfaces 96 and 94. The
following photocell 120, labeled C, is positioned to detect the
stop plate tab located between surfaces 98 and 94, and also to
detect the slowdown plate tab located between the surfaces 112 and
114.
The following six photocells 120 detect the binary number formed by
the indicium 70 and 72 which are carried by all plates. The six
photocells therefore indicate a 0 or 1 bit at the 2.sup.5 through
the 2.sup.0 bit locations of the binary code. The tenth photocell
120, labeled B, detects the stop plate tab located between surfaces
90 and 92. Finally, the last photocell 120, labeled bottom limit,
detects a special safety plate (not illustrated) which is located
at the lowermost vertical level. This photocell is connected to
override any down vertical command.
A control system which is responsive to the photocell sensor unit
55 is illustrated in FIG. 3. For clarity, the conventional
amplifiers and relay coils energized by the photocells 120 have not
been illustrated. Each relay contact has been illustrated, and is
identified by a letter corresponding to the letter of the photocell
which controls the contact, followed by a number identifying the
individual contact. When the photobeam is uninterrupted, the
associated relay is energized and the illusrrated contacts change
state. When the photobeam is broken, the corresponding relay is
deenergized and the contacts return to or remain at their normal or
unenergized position illustrated in FIG. 3.
For example, when the sensor unit 55 of FIG. 2 is located so that
no plate breaks the photobeam impinging photocell A, the normally
closed contact A-1 changes to an open state. As the A photobeam is
broken by the stop plate tab located between surfaces 96 and 94,
the relay contact A-1 returns to its normally closed position, as
illustrated.
In operation, each time the photocell sensor unit 55 detects the
lower strobe area 102 of a stop plate 50, a LOW relay 200 is
energized by a series path formed through normally closed contact
A-1 and an energized contact B-1. This indicates that the photobeam
for photocell A has been interrupted while the photobeam for
photocell B is not interrupted, which condition uniquely identifies
the low strobe area 102. Conversely, the opposite logic states for
the contacts of photocells A and B energize a HIGH relay 202. Thus,
these circuits satisfy the Boolean equations:
LOW = A.sup.. B (1)
high = a.sup.. b (2)
whenever the sensor unit 55 is vertically located between tab
surfaces 90 and 94, a SAFETY relay 204 is energized. Heretofore, a
similar SAFETY relay has been energized by providing a continuous
high-low trigger cam which has extended the whole distance between
the uppermost and lowermost stop positions for the vertical
carriage. The unique combination of tab surfaces which produce the
equation.
SAFETY = A + B (3)
eliminates the conventional high-to-low trigger indicator
heretofore provided. The output of the SAFETY relay 204 is coupled
to a conventional control circuit (not illustrated) which uses this
information to make safety correlation checks.
When neither LOW relay 200 nor HIGH relay 202 is energized, and the
photobeam for photocell C is broken, a SLOWDOWN relay 208 is
energized. This combination, namely
SLOWDOWN = LOW.sup.. HIGH.sup.. C (4)
indicates that the sensor unit 55 is adjacent a slowdown plate 60
or 62.
The output of the six binary photocells 2.sup.0 to 2.sup.n is gated
into a bin address register 210 only when valid information is
present. Each binary photocell output is in series with a STROBE
contact from a STROBE relay 212. The STROBE relay 212 is connected
through a series normally closed contact C-2 in parallel with a
pair of normally open contacts A-3 and B-3. Thus, when the Boolean
equation
STROBE = C (A+B) (5)
is satisfied, the bin address register 210 records the six bits
then being sensed. As is apparent from FIG. 2, the STROBE relay 212
is energized only when sensor unit 55 is within strobe area 100,
strobe area 102, or the strobe area between tab surfaces 112 and
114.
In summary, when the sensor unit 55 is adjacent either of the
slowdown plates 60 or 62, the SLOWDOWN relay 208 is energized, and
at the same time the binary address register 210 records the
address of that slowdown plate. When the sensor unit 55 is adjacent
the high stop position of a stop plate 50, the HIGH relay 201 is
energized, and at the same time the binary number thereof is
entered in register 210. Similarly, when the sensor unit 55 is
adjacent the low stop position of a stop plate 50, the LOW relay
200 is energized and at the same time the binary number thereof is
entered in register 210.
Any conventional speed control may be used in combination with the
above described circuit to control the movement of vertical
carriage 40. By way of example, a portion of a conventional
vertical speed control 220 has been illustrated. The address of a
selected bin from a central data source or from a manual operator
panel, is stored in a SELECTED BIN ADDRESS unit 224. A conventional
direction-of-travel circuit (not illustrated) causes the vertical
carriage 40 to be driven at a high speed of traverse and in the
proper direction toward the address stored in unit 224. Each time a
vertical address is stored in register 210, it is coupled to a
comparator 226 which compares the address with the stored selected
bin address. When a match occurs, a match relay M is energized,
thereby closing its normally open contacts M-1 and M-2.
When the first match occurs, the photocell sensor unit 55 will be
adjacent one of the slowdown plates 60 or 62, and the slowdown
relay 208 will have been energized. This closes a slowdown-1
contact and the M-1 contact, thereby completing an energizing
circuit for a conventional slowdown speed control 230 for motor and
drive mechanism 37. This causes the vertical carriage 40 to
decrease in speed to a slow speed of traverse and continue toward
the stop position. As the vertical carriage is traveling at this
slow speed, the sensing unit 55 will pass at least one other
slowdown plate. Since the different binary address of that plate
will not produce a match, relay M will not become energized and
thus the circuit is not effected.
As the sensor unit 55 is driven adjacent the stop plate, relay M in
comparator 226 will again become energized, closing contact M-2.
The contacts HIGH-2 and/or LOW-2 will similarly close as the HIGH
relay 202 and/or LOW relay 200 are energized. A conventional canned
deposit or retrieve program will have already closed either a
normally open deposit contact or a normally open retrieve contact.
Assuming a deposit cycle is to occur, the DEPOSIT contact will be
closed, and upon energization of HIGH relay 202, a path will be
completed to energize STOP CONTROL 232. This will cause the
vertical carriage to come to an abrupt halt.
While slowdown and stop indicators have been illustrated for
vertical bins, it will be appreciated that the system is equally
applicable for use with horizontal bins. Furthermore, the results
produced by uniquely identifying both slowdown and stop positions
can be accomplished by uniquely identifying only certain of the
stop and slowdown plates, with appropriate circuitry being provided
to identify the bin number of an unmarked plate by referring to
previously sensed addresses. Other modifications will be apparent
to those skilled in the art.
* * * * *