US3268097A - Stacker crane - Google Patents

Description

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Amig 23, 3956 s. F. ARMINGTON, JR., ETAL 3,268,097

STACKER CRANE Filed Dec. lo. 196s s sheets-sheet u United States Patent O 3,268,097 Y STACKER CRANE Stewart F. Armington, Jr., East Cleveiand, and Henry Engel, Euclid, Ohio, assignors to The Euclid Crane and Hoist Company, Cleveland, Ohio, a corporation of Ohio Filed Dec. 10, 1963, Ser. No. 329,415 12 Claims. (Cl. Zhi-16.4)

This invention relates to improvements in a crane for storing articles in a warehouse, and more particularly, to a stacker crane designed to save warehouse space and designed for a novel automatic control.

The present invention, as herein described and illustrated, comprises a storage frame having load support means provided on either side of an aisle in which a load carrying -apparatus travels both vertically and horizontally. The load support means illustrated comprises pairs of cantilevered arms projecting from the storage frame toward the aisle and arranged in vertical and horizontal rows whereby they dene a plurality of horizontally spaced bays and vertically spaced load levels on either side of the aisle.

The stacker crane of this invention is supported on a pair of rails disposed parallel with the aisle and suitably mounted above the storage frame on either side of the aisle. A wheeled bridge travels along the rails above the aisle for horizontal movement of the stacker crane, and a trolley is, in turn, mounted upon the bridge for movement laterally or transversely of said aisle. The trolley supports a depending mast, adapted to project `downwardly in the aisle between the rows of load support arms, and a hoist mechanism for moving a hoist carriage vertically up or down said mast. The hoist carriage carries an outwardly cantilevered turret member which in turn carries a load handling extractor fork. The extractor fork is rotatable toward either the right or left side of the aisle and includes extractor mechanism for moving the fork tines in between adjacent load support alms on either side `of the aisle for either picking up or depositing a load at the horizontal and vertical location of any of the pairs of load supporting arms. The stacker crane is movable to and from a start position beyond the storage frame where adequate space is provided for the above referred to turning movement of the fork. 'Ihis allows the aisle to be of minimum width since no turning ever takes place in the aisle.

The stacker crane of this invention may be adapted for the storage of various articles and is herein illustrated as being adapted to store elongated metal bar stock prefer- A ably carried in elongated, shallow pans for convenience in handling.

In general operation, the stacker crane is initially positioned at the start position beyond the storage frame. Suitable controls are provided whereby an operator can select a load support position. Upon pressing a start button, the forks will irst turn themselves toward the selected side of the Iaisle if they are not already so facing. Because the extractor fork is only slightly narrower than the aisle, the trolley is then caused to make a corresponding and compensating movement in the opposite direction thereby disposing the depending mast to one side of the center line of the aisle.

With the forks properly oriented, the bridge moves down the -aisle to the selected bay, and the hoist carriage moves up to the selected level. The fork then moves forwardly into the storage frame, slightly above the level of the selected load support arms if the forks are loaded and slightly below said arms if the forks are empty. The hoist carriage moves the fork downwardly or upwardly past the arms to deposit or pick up a load thereat after which the extractor fork moves outwardly into the aisle, the hoist carriage lowers to a lowermost running level,

and the bridge moves in reverse back to the start position.

One of the objects of the present invention is to provide a hoist carriage supported overhead for movement of the carriage vertically on a mast and particularly adapted to present load handling forks either to the righthand or left-hand side of an aisle along which load supporting shelf-like structures are provided. One of the advantages of the mechanism herein disclosed is that the aisle need have very slight clearance on opposite sides of the hoist carriage and load forks connected therewith, the forks being adapted to turn in either the right-hand or left-hand direction when serving load supports on diiferent sides of the aisle.

Another object of the present invention is to provide control means for automatically insuring that when a load is on the load carrying surface of the hoist carriage, it is automatically controlled to stop slightly above a load support after which the forks or extractor device will move into the load supporting area, then downward to deposit the load, then back into the aisle. On the other hand, when the load carrying surface is empty, then the hoist carriage is automatically controlled to move to the desired load support level and stop slightly below that level, after which the extractor device moves into the load support area, then upward to pick up the load and then back out into the aisle.

This invention also includes control means for insuring that a load is firmly deposited in proper position approximately parallel to the aisle before the mechanism can move through a cycle handling the load to or from a load support.

Still another improvement in the present invention is control means for insuring that the hoist carriage is locked to the mast in case the hoist cable develops a break or a slack condition, rather than to permit the hoist carriage to be dropped suddenly.

Other objects and advantages of the present invention include the particular design of the apparatus and parts for transporting a load to and from a storage space, all of which will be apparent from the accompanying drawings and description.

In the drawings,

FIG. 1 is a top plan view of a warehouse area equipped with the improved mechanism of this invention for transporting loads to and from load supporting shelf-like members in the warehouse;

FIG. la is a detail View showing the mechanism of FIG. 1 in one operative position; I

FIG. 2 is an end elevation of the same on a slightly enlarged scale;

FIG. 3 is a view taken generally along the line 3-3 of FIG. 2;

YFIG. 4 is a sectional view taken along the line 4-4 of FIG. 3;

FIG. 5 is a fragmental sectional view, enlarged, taken along the line 5-5 of FIG. 4;

FIG. 6 is a sectional View taken along the line 6--6 0f FIG. 4;

FIG. 7 is an end elevational view taken along the line 7 7 of FIG. 6;

FIG. 13 is a simplified showing of the location and action of still other limit switches;

FIG. 14 is a plan view of a control console for use with the present invention; and

FIGS. 15a and 15b constitute a single automatic control diagram for the stacker crane of this invention.

FIGS. 1 and 2 show one form of warehouse structure and one form of load handling device capable of carrying out this invention. Comment will be given later as to other forms which might embody the same inventions.

Referring to FIGS. l and 2, the warehouse structure is defined by at least two parallel rows of vertical posts `15 which define between them an aisle 1. Adjacent pairs of posts 15 in each row define laterally open bays 2, and in each bay, there are a plurality of vertically spaced load -supports I16 which, in this embodiment, comprise a plurality of pairs of cantilevered arms extending horizontally away from the posts at different levels. It should be understood that other means might be provided for supporting additional arms as indicated in dot-dash lines in lFIG. l at 21,6. It is only necessary for the purpose of this invention that there be space between the load supporting surfaces so that the extractor fork tines may move into the load supporting area and then vertically past the horizontal plane of coacting load supports either upwardly to pick up a load or downwardly to deposit a load, after which the extractor moves out of the load supporting area.

The load transporting mechanism is herein shown as supported from overhead but other types of load transporting apparatus might utilize many of the novel features of the present invention. Again referring to FIGS. 1 and 2, an overhead bridge 17 moves parallel to the aisle 2 in the direction of the arrow X. A trolley 18 riding on the bridge transversely of the aisle of the warehouse carries a generally vertical mast 19 forwardly and rearwardly along the aisle while a hoist carriage 20 is capable of moving up and down the mast 19 carrying an extractor fork 2'1 to the level of any pair of load supports 116 on either side of the aisle. The extractor fork 211 is movable either to the right or to the left into the load supporting area or bays 2 to pick up or deposit a load as previously mentioned. The extractor mechanism need not be in the form of a fork but is so shown here, as utilized in steel warehousing, for the purpose of illustration.

The bridge 17 is herein shown as comprising two parallel bridge beams 22 connected at their opposite ends by truck structures 23 which roll by means of wheels 24 on tracks 25 extending parallel to the aisle and mounted Von the buil-ding structure in any suitable manner. The bridge 17 is caused to travel along the rails 25 by electrical power as illustrated by a reversible motor 26 (FIG. 6) which drives one or more of the wheels 24. The trolley 18 is mounted 'by a plurality of wheels 27 to roll along parallel tracks 28 mounted Von top of the bridge beams 22. This movement is at right angles to the aisle and is caused by motor 29 suitably connected through mechanism 30 to one or more shafts 31 which drive wheels 27.

The vertical mast `19 is of any suitable strong and rigid construction. Preferably, it is formed of steel plates welded or riveted together to form a generally hollow square structure as seen in FIG. 4. A non-circular structure is provided in the mast cross-section so that the hoist carriage 20 may be mounted for vertical travel along the mast without any turning relative to the mast. To this end, the mast shown here is gene-rally square in section and has some strengthening and guiding ribs 19 extending vertically along substantially the full length of the mast in the mid-portion of those sides of the mast which face longitudinally up and down the aisle. In the present embodiment, these are solid steel bars bolted to the mast which provide a very strong structure. The hoist carriage is fixed to a suitable sleeve-like member 32 (FIG. 3) which has a central, vertical through opening 4 32 which embraces the mast 19 including the vertical ribs 19 as best seen in FIG. 4. Rigidly fastened to the upper surface of the member 32 are two parallel L- Shape beams 33 which extend generally parallel to the warehouse aisle. On one side -of the mast 19, the sleeve 32 and the beams 33 support a cab 34 in which an operator may ride and in which suitable controls are mounted. On the opposite side of the mast, at the far end of the beams 33, a turret bearing member 35 is rigidly secured to the beams 33 as by welding. The member 35 has a vertically extending, central cylindrical bore in which is rotatably mounted -a turret rmember 36 (FIG.

6) t-o which is rigidly attached the extractor structure.

A reversible electric motor housed in the member 35 drives turret 36 and all connected parts through a reduction gearing in housing 37 indicated on FIG. 2.

The structure supported on the turret member 36 is most clearly seen in FIGS. 6, 7 and 8. To the turret member is rigidly secured a horizontal plate 38, across one end of which is welded a structural angle member 39. These p-arts support two parallel tracks or ways 4) to support the extractor during its lateral movement. In this embodiment of the invention, the extractor takes the form of a fork although those skilled in this art will understand that it might be a platform or of some other form. Four tines 41 of the fork are rigidly secured to a back beam member 42 which in 'turn is rigidly connected to a front wall 43 and two side steel plate walls 44, all of which are rigidly connected to the horizontal plate 33 and the angle member 39 previously described. The plate members 44 are connected by an angle cross member 45 at the -top and a T-form cross member 46 at the bottom. This provides a very strong structure. For moving the extractor along the ways 4t), a reversible electric motor 47 is mounted on the cross frame member 46 and connected by drive belt 4S and suitable pulleys to gear reductions in box 49 supported on plate 43. The output from the gear reduction box is transmitted from a sprocket 50 through a chain 51 to a sprocket 52 rotatably mounted in the side plates 44 and by means of a shaft 53 which carries integral therewith a pair of pinion gears 54, each of which is drivingly engaged with a rack mounted on the bottom of each of the parallel ways 40. The extractor moves horizontally on four rollers 56, supported by stub shafts 57 in upper, overlapping portions of the plates 44. The rollers move along the ways 46 in a horizontal direction and are supported on horizontal axes. To prevent side motion of the extractor carriage with respect to the ways 40, rollers 58 are mounted to the side walls 44 on vertical axes and engage against flat, recessed 'walls 40a of the ways 46.

As previously mentioned, the hoist carriage moves vertically on the mast 19 which, in turn, is supported from the overhead trolley 18. The position of the hoist carriage is controlled by a cable 71 which is wound on a drum 72 rotatably mounted on the trolley'18 and driven .by a reversible hoist motor 73 through suitable reduction gearing in a casing 74. One end of the cable is attached to the drum 72 and the other end is connected at a bracket 75, on the trolley.

Means is provided for preventing a sudden dropping of the hoist carriage if cable 71 should break or develop lundesired slack. As best seen in FIGS. 3, 4 and 9, this comprises a roller 76 bearing against the cable 71 near the point where it passes around a sheave wheel 77 which is rotatably mounted on the hoist carriage. This roller is mounted in parallel arms 78a of a bellcrank 78 pivoted on the hoist carriage at 79. Other arms 78h of said bellcrank are pivotally connected at 80 to links 81 which extend vertically downwardly and have their lower ends pivotally connected at S2 to wedge shape members 83 housed in complementary wedge shape pockets 84 in the sleeve member 32. Each wedge member 83 carries a pair of rollers 85 which normally roll with slight clearance between the rib 19 on the vertical mast and the inclined wall of a wedge shape pocket 84 as shown in FIG. 9. Springs 86, shown in FIG. 4, normally urge the roller 76 against the cable 71. If the cable 71 breaks, or goes slack, then the springs 86 move the bellcrank arms 78a and 781; in a clockwise direction as shown in FIG. 3 which pulls the wedge members 83 vertically upwardly and causes them to jam or wedge between the surface 84 of each pocket and the surface of the vertical rib 19" on the mast. This immediately stops the fall of the hoist carriage.

FIGS. a and 15b show in diagrammatic form a simplitied, automatic control system for directing the stacker crane of this invention to move from a start position outside the storage frame into said storage frame to pick up or deposit a load thereat. The control system includes means for orienting the direction of the forks either to the right or the left and for correspondingly locating the trolley in a compensating position on the left or the right prior to the crane moving from the start position into the aisle between the rows of load supports. The control system also includes means for automatically returning the stacker crane to its start position after delivering or retrieving a load. In the electrical diagram as disclosed, it will be understood that for the purposes of simplification and clarication, only those control elements necessary to demonstrate the workability of the present invention have been shown. Therefore, it will be understood by those familiar with the art that the coils and relays shown herein as single units may, in practical application, be substituted by a number of coils or relays. It will be further understood that those coils designated as causing various elements of the stacker crane to move in a given direction control suitable contacts and circuits, not herein illustrated, to cause the motors which power the designated elements to rotate forwardly or in reverse in a well known manner and that such motors would, in practical application, be provided with automatic brakes for accurate stopping of the elements powered thereby.

Generally, all of the switches and contacts in the electrical diagram are shown in their nonnal or unactuated position in disregard to the position of any element of the stacker crane which, in such position, might cause the switch to be otherwise than as illustrated. However, `a load detecting limit switch LS12 is shown with its contacts LS12A and LSIZB ( lines 528 and 531, respectively) in the position taken when no load is on the forks. A limit switch LS6 has two sets of contacts LS6A and LS6B ( lines 522 and 537, respectively) which are actuatable only during return movement of the stacker crane from the storage frame toward the start position, and each time r such limit switch is actuated the contacts thereof reverse their positions and remain so reversed until the neXt actuation of the switch. The position of the contacts LS6A and LS6B represent those taken at the beginning of a cycle when the stacker crane is in the start position. The coil contacts LL1 to LL6 ( lines 533, 536, 540, 542, 543 and 544) are controlled by latching coils LLA in line 547 and LB in line 549 and are illustrated in the position effected by energization of latching coil LLB.

The limit switches LS13H, LS13L, LS14H and LS14L ( lines 530, 531, 538 and 539 respectively), are carried by the hoist carriage and are arranged as shown in the simplied drawing of FIG. 13. The mast 19 is provided with two lsets 'of vertically aligned trips, one set being designated as 64 and the other as 65 (FIG. 2). Each set of trips is of like number with the other set, and the individual trips are staggered so that each trip 65 is about 4" above the adjacent trip 64 of the other set. The switches LS13H, LS13L, LS14H and LS14L, though vertically arranged as shown in FIG. 13, are horizontally arranged whereby the limit switches LS13H and LS14H are tripped only by the relatively higher trips 65 whereas the limit switches LS13L and LS14L are tripped only by the relatively lower trips 64. The switches LS14L and LS14H are stop or leveling switches, the switch LS14L stopping the tines 41 of the extractor fork about 2 below the selected load support arms and the switch LS14H stopping said tines about 2 above said arms. The leveling switches act in conjunction with the switches LS13L and LS13H respectively in a manner herein later fully discussed.

The load detecting limit switch LS12 is located generally in the center of the fork 21 as best shown in FIGS. 4 and 1l. As herein illustrated, the limit switch LS12 is mounted to the T-form cross member 46 behind the back beam member 42 as Well shown in FIG. 6. Said limit switch LS12 is actuated by one end of an elongated paddle member 92 which is disposed beneath the back beam member 42 and is pivoted upon brackets 93 carried at the rear of said back beam member. The paddle member 92 has a rearwardly and upwardly projecting trip portion 94 disposed adjacent to the actuating arm of the limit switch LS12. Said paddle member projects forwardly underneath the back beam member 42 in the direction of the tines 41 and has, adjacent to its forwardly directed distal end, an upwardly angled portion 95. The bar stock stored in the storage `system herein illustrated is disposed in shallow pans 100 (FIGS. l, la and 2) which are bridged across the tines 41 when carried lby the fork 21. The angled portion 95 of the paddle member 92 projects upwardly above the upper level of the tines 41 whereby when a pan is resting upon .said tines, said angled portion and, therefore, the entire paddle member 92, is pressed downwardly causing the trip portion 94 to pivot about the brackets 93 in a counterclockwise direction thereby tripping the limit switch LS12. Said limit switch LS12 is biased to the normal, nontripped position illustrated in FIG. 6 when no load is being carried by the fork 21.

A pair of like pan positioning limit switches LS9 and LS10 are carried at either end of the back beam member 42 as best shown in FIGS. 4 and 5. Limit switches LS9 and LS10 -are actuated by identical mechanisms located at either end of the fork and, therefore, only the limit switch LS10 will be described in detail.

As shown in FIG. 5, the back beam member 42 has an opening 96 at the front face thereof with a paddle member 97 being pivoted just inside the opening at the .upper end of said opening on brackets 97a. The lower end of the paddle member 97 is pivoted forwardly and outwardly beyond the front face of the back beam member 42 a substantial distance above the tines 41 and is held in that position by a plunger 98 which is biased forwardly by a coil spring 99. When a pan 100 is properly positioned upon the fork 21, the rear edge of said pan will be back against the back beam member 42 and will actuate the limit switch LS10 by pivoting the paddle member 97 backwardly, pushing the plunger 98 longitudinally, and thereby pivoting the actuating member of said limit switch LS10. The limit switch LS9 is actuated in identically the same manner if the other end of the pan is also properly positioned with its rear edge up against the back beam member 42.

The location and function of the other limit switches' shown in simplified form in FIGS. 10-12 will be readily understood from the following description of the operation of the automatic controls illustrated in the electrical diagram of FIGS. 15a and 15b.

Electrical current for the entire control system is provided across two main leads L1 and L2. A start switch 551, biased toward the open position at all times, has normally open contacts 552 and 553 disposed in lines 502 and 506, respectively. Closing of the contacts 552 completes a circuit from the lead L1 through lines 501, 502 and parallel line 503 to energize a bridge direction coil B, a hoist direction coil H, and an extractor direction coil E. A

trolley direction coil T, in line 504 and a fork direction coil R in line 505 may also be energized by closing of contacts 552 by rst turning a selector switch 554 to the full line position as illustrated. Selector switch 554 has contacts 555 in line 504 in series with the coil T and contacts 556 in line 505 in series with the coil R which, when closed as illustrated in the full line position, will cause energization -of the [coils T and R and which when open, as illustrated by the dotted line position, will cause said coils T and R to remain de-energized. Line 501, in which the bridge directional coil B is connected, is disposed in parallel with the line 502 and has normally open contacts BI which immediately close upon the energization of the coil B thereby maintaining the energizati-on of coils B, H and E, as well as the coils T and R when the selector switch 554 is in the full line position illustrated.

A start relay coil MS is interposed in the line 506 to be energized upon the closing of the normally open contacts 553 of the .start 'switch 551. Coil MS controls normally -open contacts MSI in the main lead LI between line 506 and line 508. Until contacts MSI are closed, no current is supplied to the remaining portion of the control diagram, and when said contacts MSI open, the entire control system is sie-energized. A relay coil MMS is interposed in the line 508 and controls normally open contacts MMSI in line 507 connected in parallel around the normally open contacts 553. It will be readily understood that when the start switch SSI is closed, the coil MS is energized, the contacts MSI close, the coil MMS is energized, and the contacts MMSI close to hold the coil MS in the energized condition. The line 508 also has interposed therein in series with the coil MMS a limit switch LSI (see also FIG. 10). The limit switch LS1 is actuated by the bridge and is adapted to open momentarily upon return movement only of the bridge simultaneously with said bridge returning to the start position. This momentary opening of `LSI de-energizcs coil MMS, opens the contact MMSI, de-energizes coil MS, and opens contacts MSI whereby all electrical energy to the control diagram below the line 506 is cut off. With the start switch 551 in its normally open position, no current is then available across the line 506 or 502 and, as will herein later be fully disclosed, the normally open contacts BI will then be open whereby all control elements illustrated will be completely isolated.

The operation of the stacker crane of this invention will first be described in a cycle wherein the fork ZI is initially empty at the start position and is moved into the storage frame to pick up a load and return it to said start position. For the purpose of describing this rst cycle, it will be assumed that, at the start position illustrated in FIG. l, the trolley is located in its right-hand position on the bridge and the forks are oriented toward the left. This corresponds to the positions of the fork and trolley shown generally in FIG. v1 at 200. It will be further assumed that the operator desires to piek up a load on the right side of the aisle, in the manner indicated generally in broken line at '1 in FG. 1a, whereby the forks must be first turned to the right with a corresponding leftward movement on the part of the trolley. Therefore, the operator will first turn the selector switch 554 to the full line position as illustrated whereby to cause the forks to turn to the right and the trolley to move to the left. The operator will also depress a selector switch 557 (line 515) to determine how far down the aisle the bridge is to move and a selector 558 (line 532) which will determine how high the hoist is to go. The switches 557 and 558` represent a plurality of switches which are connected in series with a bridge counter 5159 and arhoist counter 560, respectively, and determine the exact horizontal and vertical location of the load to be picked up by the stacker crane.

The operator then depresses the start switch 551 whereby the direction coils B, H, E, T and R are all energized as described above and current is made available to the remaining portion of the electrical control diagram by the closing of the normally open contacts MSI. Energized coil B closes normally open contacts B2 in line 5-I-7 and opens normally closed contacts B3 in line 52,1; energized coil H closes normally open contacts H1 in line 564 f and opens'normally closed contacts H2 in line 537; energized coil E closes normally open contacts EI in line 540 and opens normally closed contacts E2 in line 544', energized coil T closes normally open contacts TlI in line 510 and opens normally closed contacts T2 in line 513; and energized coil R closes normally open contacts RI in line 526 and opens normally closed contacts R2 in line 527. Because the forks are oriented toward the left, a limit switch LSS (see FIG. Il) will be closed in line 524 thereby energizing a relay coil RSL.

The first movement of any element of the stacker crane will be the rotation of the fork 21 from the left to the right. This is effected by the closing of normally open contacts R1 in line 526 which thereby energizes a rotation right direction coil RlR to cause right-'hand rotation of the forks. A limit switch LSSR has normally closed contacts LSSRB, interposed in series with the right-hand direction coil, which open when right-hand rotation of the fork is complete thereby stopping the work in the right-hand position (see FIG. 11).

The trolley movement is effected by either trolley left coil TL in line 5110 or trolley right coil TR in parallel line Sil-3. Because the contacts TI are now closed and the contacts T2 are now open, only the coil TL can be energized and this will cause the trolley to move to the left. The trolley having been originally on the right, normally closed contacts LSZRA of a limit switch LSZR (see FIG. l0) in line SI2 were held open, and the forks having been initially in the left-hand position normally open contacts LSSLA of a limit switch ISSL disposed in the same line were initially closed. Line 5I?. is connected in parallel with a portion of line 516 in which said portion are normally closed contacts LSZLA of a trolley actuated limit switch LSZL (see FIG. 10) and normally open contacts LS3R1-A of the fork actuated limit switch LSSR. Because the right-hand trolley contacts LSZRA and the right-hand forks contacts LSSRA were initially open, it will be readily seen that no current was available to the trolley left coil TL until the forks 21 were rotated to the right to close the right-hand forks limit switch contacts LSSRA. This right-hand rotation of the forks deenergizes the coil R-3L in line 524 by allowing the limit switch LSS to open and energizes the coil RSR in line 523 by closing a limit switch LS7 (see FIG. l1) upon completion of the right-hand rotation. Coil RSR closes normally open contact R3R 1 in line 510A whereby a circuit is completed through said contacts, contacts LSZLA, contacts LSSRA now closed, contacts TI, and the trolley left direction coil TL. The trolley is now moved from the right to the left and upon completing its leftward movement trips the limit switch LSZL and opens the contacts LSZLA thereby breaking the circuit and stopping the trolley on the left-hand side.

After the fork rotation and the trolley movements are completed, the bridge will move forwardly from the start position into t-he aisle of the -storage frame. This is effected by energization of a bridge forward direction coil BF in line 517 by completion of a circuit through a pair of normally closed contacts 10LI in line 517A, now closed contacts R3R2 in line 517, normally open contacts LSZLB of switch LSZL, contacts R3 held closed by energized coil R, now closed contacts B2, normally closed contacts C1, and said coil BF. The normally closed contacts IOLI are controlled by a load relay ItlL in line 5213 which is energized by the closing of limit switch contacts LSIZA when a load actuates the limit switch LSIZ. Because the fork is not now carrying a load, limit s-witch contacts LS I2AA are open, coil 101. is de-energized, and contacts IODI are closed. Contacts RSR-2 are closed because the forks are rotated to the right thereby closing limit switch LS7 and energizing coil RSR. The bridge can now move forwardly because the trolley is located on the left and the normally open contacts LSZLB are closed although no movement of the bridge prior to this time was possible until the trolley had completed its leftward movement.

As the bridge moves forwardly down the aisle, a limit switch L84 (see FIG. l0) is sequentially tripped or momentarily closed at each vertical bay 2 by suitable trips 2a, and each closing momentarily energizes a bridge counter coil BC in line 5114. Each time the counter coil BC is energized, it indexes a wiper arm 561 of the bridge counter 559 the distance of one contact. Eventually, the wiper arm 561 rotates into alignment with a contact 562 corresponding to the selector switch 5157 whereby a circuit is completed through the bridge counter across the line 515 to energize a coil C. Energized coil C opens the normally closed contacts C1 in line 517 thereby isolating the bridge forward coil BF and stopping the forward movement of the bridge.

The coil C in line 515 also controls a pair of normally open contacts C2 in line 534. Contacts C2 control the energization of a hoist up coil HU and a hoist down coil HD (line 537) thereby assuring that the hoist cannot operates to lraise or lower the hoist carriage 20 until after the bridge has reached the point designated along the storage frame aisle 1. The closing of the contacts C2 completes a circuit through line 534 from the lead L1 through closed contacts 8L1, normally closed contacts L02, now closed contacts H1, normally closed contacts HD2 controlled by coil HD, and the coil HU. The contacts L02 are controlled by a load coil LO which is disposed in line 529 and which is controlled by a pair of normally open contacts ltlLZ now open because the load detector coil 10L is d-e-energized. Normally closed contacts L02 are, therefore, in the closed position, the hoist up coil HU is energized, and the hoist motor moves the empty fork 21 upwardly of the storage frame.

As the hoist carriage 20 moves upwardly, the limit switches LS13H and LS13L are sequentially tripped by the high and low trips 65 and 64 respectively. The closing of the high limit switch LS13H in line S30 does not complete a circuit to a hoist counter coil H7 disposed in the same Vline because said line 530 also has a pair of normally open contacts 1L3 now open 'because the coil 10L is de-energized. However, each closing of the low limit switch LS13L in line 531 Causes a momentary energization of said hoist counter coil H7 because a circuit is complet-ed thereto through the closed contacts LS12B of the load sensing switch LS12 which are now closed because there is no load on the tines. The hoist counter coil H7, with each energization thereof, progressively indexes a wiper arm 563 of the hoist counter S60 toward a contact 564 connected to and in circuit with the selector switch 558. This energizes a coil CC in line 532 which closes contacts necessary for stopping the upward movement of the forks and setting the extractor into motion.

Energized coil CC closes normally open contacts CCI in line 538, normally open contacts CC2 in line 539, and normally open contacts CCS in line 540. With the contacts CC2 closed, the loW stop limit switch LS14L is effective, upon closing, to energize a coil 8L also disposed in line 539. Energization of coil 8L simultaneously does two things: it opens the normally closed contacts SLI in line 53S to 'break the circuit and isolate the coil HU whereby the upward movement of the fork is stopped, and it also closes normally open contacts 8L2 in line 549 thereby energizing the latching coil LLB in the same line. Latching coil LLB latches the latching contacts LL1-LL6 to the positions illustrated ( lines 533, 536, 540, S42, 543 and S44) and at the same time closes normally open contacts LLBl in line 548 where-by coil LLB is held energized regardless of whether or not contacts 8L2 remain closed. Energized coil LLB also opens normally closed contacts LLB2 in line 547 thereby isolating the latching coil LLA and rendering it unenergizable.

At the same time that the energized coil 8L opened the normally closed contacts 8L1 to stop the upward movement of the forks, it closed normally open contacts 8L3 in the line 541 thereby completing a circuit from the lead L1 at line S40 through the contacts CCS, contacts 8L3 in line 541, latched contacts LLS in line 542, normally closed load contacts LOS, now closed contacts E1, a coil EXF, a pair of normally closed contacts EXRl, and a pair of normally closed contacts EXl. The energized coil EXF causes the extractor to move forwardly or inwardly, the fork 21 being disposed about two inches below the load Support members at that level due to the fact that the counting and the stopping of the upward movement of the extractor was effected through the low count and stop limit switches LS13L and LS14L respectively.

By referring to FIG. 6, it will be noted that when the extractor fork 21 moves into the storage frame at a pair 0f load supports 16 with the tines 41 disposed below the upper surface of the support arms, the tray is disposed in horizontal alignment with the paddle members 97 of the limit switches LS9 and LS10 but is disposed above the level of the angled portion 9S of the paddle member 92 which actuates the load detecting limit switch LS12. The result is that in picking up a load, provided said load is straight with respect to the extractor fork, the coil IOR in line 525 will always be energized -before the coil 10L in line 523. Therefore, the normally open contacts 10R1 (line 517B), 10R4 (line 533B), and 10R5 (line 537B) will always close 'before the normally closed contacts 10L1 (line 517A), 10L4 (line 533A), and 10L5 (line 537A) open. If the load is not substantially straight and one of the switches LS9 or LS10 is not actuated, coil 10R will yremain deenergized and its contacts will remain open. The subsequent lupward movement of the fork will actuate limit switch LS12 there-by opening the contacts of coil 10L whereby circuits across the lines 517, 533 and 537 are broken or cannot be established.

At the limit of the inward movement of the extractor, a limit switch LS16 (see FIG. l2) in line 545 is closed thereby energizing a coil EX in series therewith. Energized coil EX opens the normally closed contacts EX1 in line 540 to isolate the coil EXF, and the inward movement of the extractor is stopped. The coil EX also closes normally open contacts EX2 in line 533 and opens normally closed contacts EX3 in line 501. Opening of the contacts EX3 isolates all of the direction coils B, H, E, T and R whereby all of the contacts controlled thereby are reversed or returned to the position as illustrated in the diagram. For example, normally open contacts E1 in line 540 reopen and normally closed contacts E2 in line 544 close. However, there is no immediate energization of the coil EXR disposed in the same line for causing the extractor to move outwardly because normally open contacts L06 in line 543 are open due to the fact that no load is on the forks and the coil LO is de-energized. A limit switch LS15 (see FIG. 12) which is also disposed in the line 544, is closed at this time, said limit switch LS15 being adapted to close when the extractor moves forwardly to pick up or deposit a load and remaining closed until the extractor moves rearwardly to take the load back out into the aisle at which point it reopens.

Since the fork has moved out of the aisle and into the load storage frame in the low position, the next movement needs to be an upward motion of the hoist carriage 20. This is effected by the closing of the contacts EX2 in line 533. Assuming that the pan to be picked up from the load supports 16 is in proper alignment, it will close the two paddle type pan control limit switches LS9 and LS10 (see FIG. 11) when the extractor has moved all the way forwardly thereby energizing the pan control relay coil 10R in line 525. Energized coil 10R closes a pair of normally open contacts 10R4 disposed in line 533b in parallel with a pair of normally closed contacts 10L4 disposed in line 533a. Thus, if the pan is straight, the circuit across the line 533 will not be interrupted by the subsequent lifting of a load and the opening of contacts 10L4 due to the fact that the contacts 19114 will already be closed. The hoist coil HU is, therefore, re-energized tomove the fork 21 upwardly lby a circuit from the lead vL1 at line 534 through contacts C2, normally closed contacts SHl, contacts EXZ in line 533, both contacts 10L4 and 10R4, latching contacts LL1, normally closed contacts HD2, and the coil HU. As the forks move upwardly, the load is lifted from the load support thereby closing the contacts LS12A in line 528 to energize the load detector coil 10L. Normally open contacts 10L2 are consequently closed whereby the load relay L is energized. Energized coil L0 closes normally open contacts L01 in line 534, L03 in line 540, and L06 in line S43 while at the same time opening normally closed contacts L02 in line 53S, L04 in line 544 and L05 in line 542.

Continued upward movement of .the now load carrying fork 21 eventually causes the high limit switch LS1'4H to close thereby energizing the coil 8H in line 538. Energized coil 8H opens normally closed contact `8Hi1 in line 5734 thereby breaking the above described circuit to the hoist up coil HU in line 534 to stop the upward movement of the forks. Energized coil SVH also closes normally open contact 8H 3 in line 540 to cause the extractor to move outwardly or rearwardly after executing its `brief upward movement. During lthi-s brief lifting movement, the limit switch LS14L in l-ine l539 ope-ned as it rode off of the low trip 6'4 so that the contacts SLS in line 5141 opened before the load was lifted by the forks and closed the load detector lim-it switch LS12 to cause reversal of the positions of those contacts controlled by the coil L0. N-ow, however, with the load carried by the forks, normally open contacts L06 in line 5413 are closed whereby the closing of the normally open contacts SH3 completes a circuit from the lead L1 at line 540 through now closed contacts C03, now closed contacts SH3, latched contacts LL6 in line 543, now closed load contacts L06, limit switch 'LS/15 held closed because the extractor is all the way forward, normally closed contacts HU3, normally closed contacts HB3, and the extractor reverse coil EXR in line 544. The extractor is then caused to move outwardly into the aisle until the limit switch LSIS is permitted t-o open iat which point the extractor coil EXR is isolated and the extractor stops.

At the time that the extractor moved forwardly or inwardly, it will be recalled that the innermost `motion thereof energized the coil EX in line 545 thereby causing reversal of the hoist direction contacts H1 and H2 to the position illustrated. Simultaneously therewith, however, normally closed contacts EX4 in the line 537 opened to prevent an immediate energization of the hoist down coil HD. When the extractor moved outwardly or in reverse, said extractor move-d away yfrom the limit switch LS 16 in line 54S thereby de-energizing the coil EX and allowing the contacts EX14 to close, but the hoist down coil still could not be energized because a pair of normally closed contacts EXRZ controlled by the now energized extractor reverse coil EXR were opened in the line 537. Therefore, when the extractor reaches i-ts outermost or aisle position, and the extractor reverse coil EXR is deenergized, the contacts EXRZ are allowed to close thereby completing a circuit to the hoist down coil HD from the line L1 at line 534 through cont-acts C2, contacts EX4 in line 537, closed contacts LS6B of the llimit switch LS6, now closed contacts R5 of coil 10R, now closed conta-cts H2, normally closed contacts HUZ, normally closed contacts EXR2, and the coil HID. Thus the hoist begins .to move the forks in a downward direction.

At the lower limit of movement of the forks, the limit switch LS6 strikes a first trip 66 (see FIG. 12) thereby opening the contacts LS6B in line 537 and closin-g the contacts LS6A in line 522. -It will be recalled that each tripping of the switch LS6 causes it to move to the opposite position and stay there and that such tripping takes place during return movement of the stacker crane. Therefore, the hoist down coil HD is now isolated by the opening of the contacts LS6B whereas a coil H9 in line 522 is energized bythe closing of the limit switch cont-acts LS6A. Energized coil H9 closes normally open contacts H91 inline 519 which is connected across the lines 517 and 521. It wi-llbe recalled that ythe trolley is located on the left whereby the limit switch contacts LSZLB are held closed and'the forks are located toward the right whereby the contacts RSRZ are also closed. Therefore, upon energization of the coil H9, a circuit is formed from the lead line L1 at line 5117 through contacts 10R1 in line 517B, now closed because the pan is straight on the forks, contacts R3R2, contacts LSZLB, contacts H91 in line 519, contacts 8H4 in line 521, contacts 8L4, now closed contacts B3, contacts EXS controlled by the now de-energized coil EX, the bridge reverse actuating coil BR, normally closed contacts HU1, and normally closed contacts HD1. The bridge then moves rearwardly back to the start position at which point trips 617 (see FIG. 12) and 68 (see FIG. 10) simultaneously respectively reset the limit switch LS6 to where the contacts thereof are again positioned las illustrated and momentarily open the limit switch LS1 in line S68 whereby all electrical power tothe control system is cut off by the de-energization of coil MMS, the opening of contacts MMSl, the de-energization of coil MS, and the opening of contacts MSl in the lead Ll. This causes the entire stacker crane to stop ait the start position at which point the load retrieved may be disposed of in any desired manner. It will be noted in FIG. 12 that limit switch LS6 has two actuating arms for tripping in both a vertical and a horizont-al direction.

The second cycle of operation to be described will be one in which the fork of the stacker crane is loaded and such load is delivered from the start position beyond the storage frame aisle to a preselected storage position as determined by the closing of selector switches such as those represented at 55.7 in li- ne 515 and 558 in line 532. For the purpose of the following description it will be assumed that the forks have been loaded in any suitable manner and are oriented toward the right with the trolley being correspondingly positioned on the left. It will be further assumed that it is desired by the operator to deliver a load on the left side of the aisle opposite to that toward which the forks are initially directed.

To effect service to the left, the selector switch 554 in lines 504 and 05 is turned to the dotted line position as illustrated wherein the contacts 555 and S56 are opened and the trolley and fork direction coils T and R respectively, are isolated and will remain de-energized throughout the entire cycle. Upon depressing the start switch 551 in lines 502 and Silo, only the bridge, hoist, and extractor direction coil-s B, H and E will be energized by the closing of normally open contacts 552 in line 502. Contacts B1 in line 501 immediately close thereby holding the circuit to the coils B, H and E. The closing of normally open contacts 553 will again energize coil MS, close contacts MS'l in the lead L1, energize the holding coil MMS in line S018, and close the holding contacts MMSI in line 507. Thus, electrical energy is avail-able to the entire cnritrol system.

The contacts T1 and T2 in lines 510 `and 513 respectively will -be in the position illustrated because the coil T is de-energized. The trolley now positioned on the left, can, therefore, only move toward the right by energization of the coil TR. With the trolley on the left, limit switch contacts LSZLA in line 510 will be open, and with the forks on the right the limit switch contacts LSSRA will be closed. Since the contacts LS3LA in line 512 will be open, the trolley cannot move until the forks are rotated to the left to complete a circuit across said line 512. Contacts R3R1 in Iline 510A will be closed because the forks are on the right, and contacts R3L1 in line 516B will close when the forks have rotated to the left. The same will be true of contacts R3R2 and R3L2 in lines 51,7 Iand 521 of the bridge direction coils BF and lBR recannot be energized because the contacts R3'in the same line are now open due to the de-energized condition of coil R in line 505. With contacts R3L2 and contacts LS2RB located inline 521^both being open as well as the contacts B3, neither of the coils BF or BR c'anbe energized across that line. Consequently, the r'st coil tobe energized will be the fork rotation left coil RL in line 527 by a circuit from the lead L1 through the now closed contacts R2, limit switch contacts LSSLB, said coil RL, normally closed contacts C3 controlled by the coil C, and normally closed contacts BRI controlled by vthe bridge reversing coil BR. The forks now rotate from the right to the left closing the contacts R3L1 vin linev 510A and R3L2 in line 521 by energizing the coil RSL i-n line 524 when limit switch LSS closes upon complete rotation of the forks to the left. Since the right hand trolley limit switch contacts LS2RB in line 521 are still open, there is still no energization of either bridge coil, but the tripping of the left-hand fork limit switch LS3L closes contacts LSBLA -in line 512 and completes a circuit from the lead L1 at line 510 through the now closed contacts R3L1 in line 510B, contacts LSZRA and LS3LA in line 517, and contacts T2 in lline 513 to energize the trolley right coil TR. At the same time, coil RL is isolated by the opening of contacts LSSLB. The trolley then moves to the right thereby tripping the right-hand trolley llimit switch LS2R to complete a circuit from the lead -L1- at line 517 through closed contacts R1 in line 517B, held closed because the forks are carrying a properly positioned pan and coil 10R is energized, contactsV RSLZ and LS2RB fin line 521, now closed cont-acts R4 in line S20, now closed contacts B2 and normally closed contacts Cl-finiline 517 to the bridge forward coil BF. Thus, the bridgegs caused to move forwardly down the aisle with the forks carrying a load. It will be noted at this point that 'if the load were not properly positioned thereby allowing one of the aznza'ggarosv :limit switches LS9 or LS10 inline 525 to remain open,

the bridge could not move because the contacts 10Rl in line 518 would not be closed and the normally-closed contacts 10L1 in line 516 would be held open' by energized coil 10L in line 528, energizedbecause the contacts LS12A of limit switch 1812 would be closed. Therefore, it w-ill be readily understood that the bridge cannot move into the aisle at all with an improperly positioned load thereby yobviating any chance of a crooked loatlr striking some part of the storage frame therein.

The forwardly moving bridge counts out as before by the sequential and momentary closings of the'limit switch LS4 lin line 514 thereby sequentially and momentarily energizing the counter coil BC and indexing thewiper arm 561 of the bridge counter 559 toward the contact 562 in line with the closed selector switch 557 (line 515). When the bridge counter counts out, coil C is energized as before thereby opening the normally closed contacts C1 in line 517 to stop the forward motion of the bridge and closing the normally open contacts C2 in line 4534 -to energize circuits to the hoist direction coils.

Because the forks are loaded and the load is'straight, contacts L01 and 10R2 in line 534 are now closed. Also, energization of the 'hoist direction coily H in line 502 has closed the normally open contacts H1 in the same line. Therefore, closing of normally open contacts C2 completes acircuit from the lead L1 through said contacts C2, normally closed contacts SHI, cont-acts L07, contacts 110R2, contacts H1, contacts HD2, to the coil HU. The hoist then moves the fork and the load upwardly and the hoist count coil H7 in line 530 is momentarily energized at each level by the high count limit switch LS13H due to the fact that the normally open contacts 10L3 in line 530 are closed. The forks being loaded, the contacts LSlZB of the limit switch LS12 in line 531 are now open whereby the corresponding closings of the limit switch LS13L vor another load stored has no eileconthe count coil.' As before, the count coil selector switch 558 in line 532. When the hoist coutr'--\ counts out, coil CC in vline 532 is energized as before thereby closing the contacts CCI in line 538 to make elective the nent closing movement of the lhigh stop limit switch LS14H. The closing of limit switch LS14H energizes the coil'SH in line 538 thereby opening the normally closed contacts 8H1 in line 534 and stopping the above described upward movement of the fork. vCoil 8H also closes normally open contacts SH2 in line 547 to energize latching coil LLA by a circuit -from the lead L1 through said contacts 55H2, normally closed contacts LLB2, and said coil LLA. Coil LLA immediately closes holding contac'ts LLAI in line 546 to keep itself energized attire same time opening contacts LLAZ in line 549 to isolate tihe other latching coil LLB. The effect of energizing latching coil LLA is to 'open the contacts LLI inline 533, close the contacts LL2 in Aline 536, close the contacts LL3 in line 540,1olose the `contacts LL4 in line 544, open the oontacts'Ll5 in line 542, and open the contacts LL6 in line 543.v

The energized coil 8H also closes normally open ccntaots SH3 in line 540 to complete a circuit from the lead L1 through'now closed contacts CC3, said contacts SH3, now closedlatching contacts LL3, load contacts L03 held closed by fnow energized loadcoil LO, contacts E1 held closed by energized coil E in line 503, the extractor tion ward coilHEXF, and the two normally closed contacts EXRI :and BXL The extractor therefore moves in with the load at the high position about Zmabove the lload support members of the selected level. l

When lthe extractor reaches fthe extent of its forward or inward motion, the |limit switch LS16 in line 546 again closes toen'ergize thev coilEX. `This opens norm-ally closed contacts EXl in line 540 land stops thel inward :movement of the extractor. It also closes the normally 'open contacts EX2' in line 533 but since the vnormally closed latching contacts LLI are now open, line 533 is not usablein the present cycle. :Normally closed contacts EX3 in line-'501 again open thereby effecting the above describedreversing of all of the contacts controlled by thev'direction coils B, H and E. Nonnallyvclosed cont'acts EX4 in line 541`are open `to assure that the tbridge cannot move in reverse. Contacts 8H4 in line 521 will alsobe open at thisv time. Another set rof contacts EXG in line 536-will be closed by the coil EX, and this will complete the next available circuit which is 4from the lead L1 Tat the line 534 through contacts C2, contacts 8L1 inline 535, said contacts EX6 in r'line/536, now latched contacts yLLZ i-n the same line, normally closed contacts HUZ and EXRZ in line 537 toi the hoist down coil HD.

The hoist will then move the forks downwardly until the low stop limit switch LS14L in line 539 is closed-thereby energizing tfhe coil 8L and opening the contacts SLI in Iline 535. During this brief downward movement, the load has' been removed from the forkswith the con`sequent changing of the contacts of the load detector limit switch LS12 to the position as illustrated in lines 528 and 531. This isolates coils 10iJ and LO Iand causes reversals ofthe contacts controlled Ithereby in the usual nia-nner.

The energization of the coil 8L in line 539 sets up the next succeeding circuit by closing normally open contacts 8L3 in line 541 to complete a circuit from the lead L1 a-t line 540 through contacts CCS, said contacts 31.3 in line 541,.ncw latched contacts LL4 and mow closed load contacts L04 in line 544,'flmit switch LSIS which closed when the extractor moved forwardly, now closed contacts E2, normally closed contacts HUB and HB3, and the extractor reverse coil EXR. Thus the extractor moves rearwardly or outwardlyuntil LS15 is allowed to open at which time the extractor stops.

The outward movement of the extractor, allowed the limit switch LS16 in line 515 to reopen thereby defenerf gizing the coil EX and allow-ing the normally closed con tactsEX4 in line 537 to close. However, sincev thecoil "EXR in line 544 was energized before the cle-energizetion of the coil EX in |line 545, normally closed oontacts EXR2 in line 537 prevented an immediate energization of the hoist down coil HD. With the extractor moved all the way out, the coil EX-R is now dre-energized and the contacts EXR2 -are allowed to close whereby the hoist down coil is now :automatically energized to move 'the empty forks downwardly until such time as the limit switch LS6 is tipped to reverse the contacts LS6A and LS6B thereby stopping the downward movement of the hoist carriage and forks 21.

As before, closing of theltimit switch contacts LS6A energizes the coil H9 and closes the contacts H91, but this |has no effect on bridge return motion since the contacts RSRZ and LSZLB in line 517 are both open. The path for energizing the bridge reverse coil BR in line 521 out of alignment, the opening of contacts 10R1 would likewise stop the movement ot the stacker crane.

' The normal, running level of the stacker crane as herein illustrated is one in which the tines are disposed just be low the lowermost level of load supports 16. Thus, actuation of the hoist counter-,and the lvertically acting counter and leveling switches takes place above the normal horizontal running level. The crane is positioned at this running level whenever it is at the start position.v However, it will be readily understood that the running level may, if desiredbe disposed at another level withv the hoist counterV counting downwardly or, in the case of an intermediate running level, both gppwardly and downwardly from a median position. Therefore, while the embodiment of the invention herein illustrated and vdescribed shows a normal running'level at the bottom of the storage is, therefore, through the now closed contacts RSLZ and LSZRB. The bridge could not previously move .in reverse because either the contacts 8H4 were open when the forks reached the high position at thef chosenvload level, the normally closed contacts EX4 were open when theextractor was moved all the way :forwardly and LS16 in line 545 was closed, normally closed contacts HUI were open while the forks were moving upwardly, or Vthe contacts HD1 were held open while the forks were moved downwardly bythe coil HD inline 537. Now, all of these contacts are closed along with the contacts yB3 and 8L4 whereby the bridge reverse coil BR is immediately energized.' The contactsloLlin line517A are, ofcourse, closed at this time because there is no .load on the fork. The result is that the bridge now returns tothe start po sition at which pointv the limit switch L56 is tripped to reverse the position of the contacts LS6A `andLStiB and cause them to .return to the position' illustrated simultaneously with the momentary opening of the limit switch LS1 in line 508 to cut off all current to the control system as described in connection with the first cycle.

It will be understood that if at the start of either cycle as described above the fork tand trolley are already oriented in the positions desired to service the sideY of the aisle selected, then the above described preliminary adjustments of fork and trolley would be unnecessary and the stacker crane, loaded or unloaded, `wouldbegin to move immediately into the aisle as soon as the start but ton was depressed. It will be further noted that because of the parallel arranged contacts 10L1 and IOR! in line 517, the parallel arranged contacts 10L4 and 10R4' in line 533, the paraillel arranged contacts 10L5, and 10R5 in line 537, and the series connected contacts 10L and 10R2 in line 534, the bridge cannot move forwardly or rearwardly and the fork cannot move upwardly or downwardly with a crooked load.y If the fork goes in low, and the pan is not straight, coil10R in li-ne 525 will not be energized, contacts 10R4 in line 533 will not be closed, and the hoist up coil HU will not'ibe energized. If the bridge is moving forwardly by the coil BF in linef517 with a load on the fork and the load is kn-ockedout of alignment thereby opening one of the limit switches L59 or LS10, the circuit which is through the contacts 10R1 inline 517B will be broken because said contacts 10R1 will will open. 'It a load which has just been picked up is knocked out of alignment while the forks are-moving |downwardly, the circuit will be through contacts 10R5 s in lme537B .and this will likewise be broken tostop the movemeneoff the loaded stacker crane. De-energization of the coil HD and closing of the contacts HD1 in line 521 would not cause the bridge to go into reverse because it would likewise be dependent upon pain control coil contacts 10Rl in line ,518 which would also immediately open. If, while the bridge is moving in reverse with a load back toward the start position said load is knocked frame, the invention is not intended to be limited to that arrangement.' It will be further readily understood that although the present embodiment cf the control means determines sequential movements of the bridge and hoist carriage, these motions may be effected simultaneously throughout at least-a portion ofthcir movements if so desired.`

The present embodiment of the invention illustrates a use of the stacker crane in connection with a storage frame `having a'lsi'ngle aisle along which the crane travels. A

number of such aisles may be serviced by a single crane by increasing the length of the bridge 17 and the distance between thetracks 25 whereby said bridge spans a number of aisles ot the type illustrated. f

It willbe understood that many other changes in the details of' the invention as herein'described and illustrated maybe made without, however, departing from the spirit thereof or the scope of the appended claims.

What is claimed is: t

1. Load transfer apparatus having loadhandling means movable vertically vand horizontally in an aisle between vertically 'and horizontally spaced load support means comprising` overhead carrier means movable parallel with said aisle;a trolley movable transversely of said aisle on said carrier; power means for moving said trolley; a mast depending from said trolleyvandl laterally movable said aisle by said trolley; Vsaid load handling means carried by said mast; said load handling means being movable up and down said mast and having generally horizontal,

cantilcvered liftingmeans rotatable from one side of said aisle to theother and adapted to pick up o r deposit a load from any of said load support means on either side of said aisle; power means for rotating said lifting means; power means for moving said load handling means up and down said mast; saidtrclley adapted to position said mast toward one side of said aisle when said cantilevered litting means is oriented toward the other side of said aisle in such manner as to minimize the necessary width of said aisle for :allowing vertical andhorizontal movement of said load handling means in said aisle; anda safety interl a t1nel movable across said bridge` transversely tossici" lock connection between said trolley moving power means and said power means for rotating said lifting means enabling operation of said power means for moving said load handling means up and down said mast only when said mast and said lifting means are orientedy toward opposite sides of said aisle. l

2. load transfer and storage apparatus comprising a storage frame having parallel rows of vertically and horizontally spaced loadA support means defining van aisle therebetween and opening into said aisle; a bridge spanning said aisle and movable parallel with and above said aisle;

aisle; a mast depending from said trolley in general ulign- @Artena-with said aisleiandsltiftable laterally of said aisle by said trolley; a hoist carriage vertically movably mounted on said mast; a turret carried by said hoist carriage; an extractor .fork carried by said turret and rotatable thereby toward said load support means on either sideof said aisle; Said extractor forli comprising means carrying gcnerally horizontally directed fork tines and means for moving said tines horizontally relative to said hoist carriage out of said aisle and into the storage area of said storage frame; power means for rotating said fork tines toward one or the other sides of said aisle, shifting said trolley on said bridge in a compensating direction opposite to the direction of said tines, moving said hoist carriage upwardly and downwardly of said mast to and from the different levels of said load supports, and moving said bridge along said aisle to the different horizontal positions of said load support means; and automatic control means for sequentially causing said tines to be oriented toward one side of said aisle and said trolley to be shifted toward the other side of said aisle :at a start position beyond said`storage frame, said bridge to move longitudinally of said. aisle to a preselected horizontal position and said hoist carriage to move vertically to a preselected level and stop slightly -above or below a selected load support means, said fork tines to move into said storage frame, said hoist carriage to move vertically past the level of said selected load support means to deposit a load thereat or pick up a load therefrom, said fork tines to move b-ack into said aisle, and said hoist carriage to move vertically and said bridge to move horizontally back to said start position.

3. Load transfer and storage apparatus comprising a storage frame having parallel rows of vertically and horizontally spaced load support means defining an aisle there# between and opening into said aisle; a bridge spanning said aisle and movable parallel with and above said aisle; a trolley movable across said bridge transversely to said aisle; a mast depending from said trolley in general alignment with said aisle and shiftable laterally of said aisle by said trolley; a hoist carriage vertically movably mount-` ed on said mast; an extractor carried by said carriage and rotatable thereby toward said load support means on either side of said aisle; said extractor comprising a generally horizontally directed load surface and meansfor moving said load surface horizontally `relative to said hoist carriage out of said aisle and into a l.storage area of said storage frame; power means for rotating said load surface toward one or the other sides of said aisle, shifting said trolley on said bridge in a compensating direction opposite to the direction of said load surface, moving said hoist carriage upwardly and downwardly of said mast to and from the different levels of said load supports, and moving said bridge along said aisle to the diierent horizontal positions of said load support means; and control means for actuating said power means including means responsive to said load surface turned toward one side of said aisle causing said trolley to automatically shift to the other side of said aisle and means responsive'to said load surface turned toward said other side of said aisle causing said trolley to automatically shift to said one side of said aisle.

4. Load transfer and storage apparatus comprising a storage frame having parallel rows of vertically and horizontally spaced load support means dening an aisle therebetween and opening into saidaisle; 'a bridge spanning said aisle and movable parallel with and above said aisle; a trolley movable across said bridge transversely to said aisle; a mast depend-ing from said trolley in general alignment with said aisle and shiftalble laterally of said aisle -by said trolley; a hoist carriage vertically movably mounted on said mast; a turrent carried by said hoist carriage; an extractor fork carried by said turrent and rotatable thereby toward said load support means on either side of said aisle; said extractor fork comprising means carrying generally horizontally directed fork tines and means for moving said tines horizontally relative to said hoist carriage out of said aisle and into the storage area of said storage frames; power means for rotating said rfork tines toward one or the other sides of said aisle, shifting said -trolley on said bridge in a compensating direction opposite to the direction of said tines, moving said hoist carriage upwardly and downwardly of said mast to and from the different levels of said load supports, and moving said bridge along said aisle to the'different horizontal positions of said load support means; load position control means act-uatable by a load disposed in a predetermined position upon said tines; load detector control means actuatable'by a loaden sa-id tines; said power means for said bridge and said hoist carriage responsive to said load position control means in the unactuated condition and said load detector control means concurrently in the actuated condition whereby said bridge and said hoist carriage will not move.

5. Load transfer and storage apparatuscomprising a storage frame having'parallelrows of vertically and horif zontally spacedA load support means defining an aisle therebetween and opening into said aisle; abridge spanning said aisle andmovable parallel with and above said aisle; a trolley movable across said bridge. transversely to said aisle; a mast depending from said trolley in gen-A eral alginment with said aisle andshiftable llaterally of said aisleby said trolley; a hoist carriage vertically movably mounted on said mast; a turretcarried bysaid hoist carriage; an extractor lfork carried by said turret and rotatable thereby toward said load support means on either side of said aisle; said extractor fork comprising means carrying generally horizontally directed fork tines and means for moving said tineshorizontally relative to said hoist carriage out of the aisle and into the storage area of said storage frame; power means for rotating said fork tines toward one or the other sides of said aisle, sh-ifting said trolleyon said b-ridge'in a compensating direction opposite to the direction of said tines, moving said hoist carriage `upwardly and downwardly of said mast to and yfrom the different levels ofsaid load supports, and moving said bridge along said aisle to the dif-A ferent horizontalpositions of -said load support means; electric control means lfor said apparatus including a pair of vertically spaced, high and low counterswitches movable with said hoist carriage; two sets of vertically spaced trips carried by said mast, each trip of one said set being disposed above the level of a corresponding trip o-f the other` set with the higher trips actuating the rhigh counter switch and the lower trips actuating the low counter switch; a vertical counter for selectively determining the level at which said fork tines arey to st-op for retrieving or depositing a load; said counter responsive to either of said counter switches; a load detector switch carried by said fork tines and actuatable by a load on said tines; said counter responsive Vto said detector switch whereby when said detector switch is actuated, said counter responds only to the tripping of said high counter switch, and when said detector switch is unactuated, said counter switch responds only to the tripping of said low counter switch.

6. In a load storage apparatus, a vertically xed mast; a plurality of vertically spaced load support means defining a vertical storage area disposed adjacent to said mast; a load carrier movable vertically on said mast; power means for moving said carrier; electric control means for said apparatus including a pair of vertically spaced, high and lower counter switches movable with said carrier; two sets of vertically spaced trips carried by` said mast, each trip of one said set being disposed above the level-of a corresponding trip of the other set with the higher trips actuating the high counter switch and the lower trips actuating the low counter switch; a vertical counter means for selectively determining the level at which said load carrier is to stop f-or retrieving or depositing a load; said counter means responsive to either of said counter switches; a load detector switch carried by said load carrier and actuatable by a load on said carrier; said counter means responsive to said detector switch whereby when said detector switch is actuated, said counter means responds only to the tripping of said high counter switch, and when said detector switch is unactuated, said counter means responds only to the tripping of said low counter switch.

7. In a storage apparatus as set forth in claim 6; said load carrier comprising a horizontally movable extractor having a cantilever lift member; control means for causing said carrier t-o move upwardly along said mast to a position slightly above or below a load support means, said extractor to move said lift member into the vertical storage area of said support means, said carrier to move said lift member through the horizontal plane of said support means for picking up or depositing a load thereat, and said extractor to move said lift member horizontally away from said support means; high and low carrier stop switches movable with said carrier, disposed below saidA high and low counter switches respectively, and actuated by said higher and lower trips respectively; sai-d stop switches responsive to said counter means whereby when said counter means counts out by the last actuation of a counter switch, said carrier is stopped by the stop switch immediately therebelow.

`8. In storage apparatus as set forth in claim 7; extractor power means for moving said lift member into the vertical storage Iarea of said support means; said extractor power means being responsive to both of said stop switches whereby said extractor moves said iift member into the vertical storage area of said support means upon actuation of either of s-aid stop switches to stop the movement of said carrier.

9'. In storage .apparatus as set forth in clai-m 8; lim-it switch means actuated upon the complete inward movement of said lif-t member; said iirst mentioned power means responsive to actuation of said limit switch means to cause said carrier to move said lift member through the horizontal plane of said supp-ort means in a short vertical movement; said iirst mentioned power means being further responsive to said stop switches whereby when said carrier is initially stopped by actuation of one of said stop switches, sai-d short vertical movement is terminated upon actuation of the other stop switch.

10. Load transfer and storage apparatus comprising a storage frame having parallel rows of vertically and horizontally spaced load support means defining an aisle therebetween and opening into said aisle; a bridge spanning said aisle and movable parallel with and above said aisle; a trolley movable across said bridge transversely to said aisle; a mast depending from said trolley in general alignment with said aisle and shiftable laterally of said aisle by said trolley; a hoist carriage vertically movably mounted on said mast; a turret carried by said hoist carriage; an extractor fork carried by said turret and rotatable thereby toward said load support means on either side of said aisle; said extractor fork comprising means carrying generally horizontally directed fork tines and means for mov-ing said tines horizontally relative to said hoi-st carriage out of said aisle and into the storage area of said storage frame; power means for rotating said fork tines toward one or the other sides of said aisle, shifting said trolley on said bridge in a compensating direction opposite to the direction of said tines, moving said hoist carriage upwardly and downwardly of said mast to and from the different levels of said load supports, and moving said bridge along said aisle to the different horizontal positions of said load support means; controls for said apparatus including control means responsive to said fork tines turned either toward one side of said aisle or the other; control means responsive to said trolley positioned either adjacent to one side of said aisle or the other; said power means fo-r said kbridge responsive to both said control means whereby said bridge cannot move unless said fork tines and said trolley are -oppositely oriented relative -to said aisle.

11. Storage apparatus comprising a storage frame having parallel rows of vertically and horizontally spaced load support means defining an aisle therebetween; a bridge spanning said aisle and movable parallel with and .above said aisle; a trolley movable across said bridge transversely to said aisle; a mast depending from said trolley into said aisle and shiftable laterally of said aisle by said trolley; a hoist carriage vertically mov-ably mounted on said mast; a load extractor mechanism rotatably carried by said carriage and rotatable toward said load support means on either side of said aisle; said mechanism comprising means carrying generally horizontally directed load lifting means and means for moving said load lifting means horizontally relative to said hoist carriage out of said aisle and into the storage area oi said storage frame; and power means operatively associated with control means effective in an automatic cycle for rotating said mechanism toward one or the other sides of said aisle, shifting said trolley on said bridge in a compensating direction opposite to the direction of said load lifting means', moving said hoist carriage upwardly and downwardly of said mast to and from the different levels of said load supports, and moving said bridge along said aisle to the different horizontal positions of said load support means.

12. In a warehouse system lfor moving loads into and out of storage racks having load receiving stations at different level-s located adjacent an aisle, a carrier having a load supporting means movable along said aisle and to various levels of said racks and into and out of said racks to deposit and pick up loads, power means for moving said carrier and for moving said load supporting means into and out of said racks with vertical manipulation to deposit and pick up loads, a series of high and lower level indicators on said carrier for stopping said load support means respectively above or below a series of associated load receiving stations, two level detectors responsive respectively one to said high level indicators and one to said lower level indicators, a load detector device carried by said loa-d supporting means and actuated by a load thereon, andoperative connections causing said high level detectors to respond only to said load detector device in actuated condition and causing said lower level detectors to respond only to said load detector device in unactuated condition.

References Cited by the Examiner UNITED STATES PATENTS 1,108,723 8/1914 Dolph 187-88 1,389,867 9/1921 Griffin f 187-88 X 2,737,303 3/1956 Held et al. 214-164 2,765,928 10/1956 Riemenschneider 214--164 X 2,869,739 1/.1959 Davis 214-730 X 2,899,087 `8/ 1959 Jacobsen.

3,034,675 5/1962 Quayl 214--16.4 X 3,049,247 8/ 1962 Lemelson 214-164 FOREIGN PATENTS 154,013 11/ 1953 Australia. 625,865 8/ 1927 France. 1,072,557 12/ 1959 Germany.

GERALDI M. FORLENZA, Primary Examiner.

R. B. JOHNSON, Assistant Examiner.

Claims (2)

1. LOAD TRANSFER APPARATUS HAVING LOAD HANDLING MEANS MOVABLE VERTICALLY AND HORIZONTALLY IN AN AISLE BETWEEN VERTICALLY AND HORIZONTALLY SPACED LOAD SUPPORT MEANS COMPRISING OVERHEAD CARRIER MEANS MOVABLE PARALLEL WITH SAID AISLE; A TROLLEY MOVABLE TRANSVERSELY OF SAID AISLE ON SAID CARRIER; POWER MEANS FOR MOVING SAID TROLLEY; A MAST DEPENDING FROM SAID TROLLEY AND LATERALLY MOVABLE IN SAID AISLE BY SAID TROLLEY; SAID LOAD HANDLING MEANS CARRIED BY SAID MAST; SAID LOAD HANDLING MEANS BEING MOVABLE UP AND DOWN SAID MAST AND HAVING GENERALLY HORIZONTAL, CANTILEVERED LIFTING MEANS ROTATABLE FROM ONE SIDE OF SAID AISLE TO THE ANOTHER AND ADAPTED TO PICK UP OR DEPOSITE A LOAD FROM ANY OF SAID LOAD SUPPORT MEANS ON EITHER SIDE OF SAID AISLE; POWER MEANS FOR ROTATING SAID LIFTING MEANS; POWER MEANS FOR MOVING SAID LOAD HANDLING MEANS UP AND DOWN SAID MAST; SAID TROLLEY ADAPTED TO POSITION SAID MAST TOWARD ONE SIDE OF SAID AISLE WHEN SAID CANTILEVERED LIFTING MEANS IS ORIENTED TOWARD THE OTHER SIDE OF SAID AISLE IN SUCH A MANNER AS TO MINIMIZE THE NECESSARY WIDTH OF SAID AISLE FOR ALLOWING VERTICAL AND HORIZONTAL MOVEMENT OF SAID LOAD HANDLING MEANS IN SAID AISLE; AND A SAFETY INTERLOCK CONNECTION BETWEEN SAID TROLLEY MOVING POWER MEANS AND SAID POWER MEANS FOR ROTATING SAID LIFTING MEANS ENABLING OPERATION OF SAID POWER MEANS FOR MOVING SAID LOAD HANDLING MEANS UP AND DOWN SAID MAST ONLY WHEN SAID MAST AND SAID LIFTING MEANS ARE ORIENTED TOWARD OPPOSITE SIDES OF SAID AISLE.

12. IN A WAREHOUSE SYSTEM FOR MOVING LOADS INTO AND OUT OF STORAGE RACKS HAVING LOAD RECEIVING STATIONS AT DIFFERENT LEVELS LOCATED ADJACENT AN AISLE, A CARRIER HAVING A LOAD SUPPORTING MEANS MOVABLE ALONG SAID AISLE AND TO VARIOUS LEVELS OF SAID RACKS AND INTO AND OUT OF SAID RACKS TO DEPOSITE AND PICK UP LOADS, POWER MEANS FOR MOVING SAID CARRIER AND FOR MOVING SAID LOAD SUPPORTING MEANS INTO AND OUT OF SAID RACKS WITH VERTICAL MANIPULATION TO DEPOSITE AND PICK UP LOADS, A SERIES OF HIGH AND LOWER LEVEL INDICATORS ON SAID CARRIER FOR STOPPING SAID LOAD SUPPORT MEANS RESPECTIVELY ABOVE OR BELOW A SERIES OF ASSOCIATED LOAD RECEIVING STATIONS, TWO LEVEL DETECTORS RESPONSIVE RESPECTIVELY ONE OF SAID HIGH LEVEL INDICATORS AND ONE TO SAID LOWER LEVEL INDICATORS, A LOAD DETECTOR DEVICE CARRIED BY SAID LOAD SUPPORTING MEANS AND ACTUATED BY A LOAD THEREON, AND OPERATIVE CONNECTIONS CAUSING SAID HIGH LEVEL DETECTORS TO RESPOND ONLY TO SAID LOAD DETECTOR DEVICE IN ACTUATED CONDITION AND CAUSING SAID LOWER LEVEL DETECTORS TO RESPOND ONLY TO SAID LOAD DETECTOR DEVICE IN UNACTUATED CONDITION.

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