US3730102A

US3730102A - Material handling system

Info

Publication number: US3730102A
Application number: US00117321A
Authority: US
Inventors: G Pipes
Original assignee: Eaton Corp
Current assignee: Eaton Corp
Priority date: 1971-02-22
Filing date: 1971-02-22
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01

Abstract

An improved material handling system includes a main track for guiding movement of a vehicle to and from aisles between adjacent rows of bins. The vehicle is transferred from the main track to tracks in a selected aisle by operating transfer arms on the vehicle to pivot transfer rails forming lengths of the main track into alignment with the aisle tracks. Once the vehicle has entered the selected aisle and moved beyond the transfer rails, biasing springs pivot the transfer rails back into alignment with the main track where the transfer rails are held in place by latch assemblies. When the vehicle starts to leave the selected aisle and is approaching the main track, the vehicle operates trip linkages to release the latch assemblies. Continued movement of the vehicle toward the main aisle operates other linkages to pivot the transfer rails back into alignment with the aisle tracks against the influence of the biasing springs.

Description

United States Patent 1 91 Pipes [451 May 1, 1973 41 MATERIAL HANDLING SYSTEM [75] Inventor: George R. Pipes, South Euclid, Ohio [73 Assignee: Eaton Corporation, Cleveland, Ohio [22] Filed: Feb. 22, 1971 [21 Appl. No.: 117,321

[52] US. Cl ..104/48, 104/130 [51 Int. Cl. ..B60s 13/02 [58] Field of Search ..104/40, 48, 49, 50, 104/99, 100, 96, 101, 130; 214/164 A, 16.4

[56] References Cited UNITED STATES PATENTS 3,485 ,390 12/ l 969 Atwater ..104/48 3,432,046 3/ l 969 Krusinski. 104/48 3,170,41 l 2/1965 Howard 104/40 Primary Examinep-Drayton E. Hoffman Attorney-Yount and Tarolli 5 7 ABSTRACT An improved material handling system includes a main track for guiding movement of a vehicle to and from aisles between adjacent rows of bins. The vehicle is transferred from the main track to tracks in a selected aisle by operating transfer arms on the vehicle to pivot transfer rails forming lengths of the main track into alignment with the aisle tracks. Once the vehicle has entered the selected aisle and moved beyond the transfer rails, biasing springs pivot the transfer rails back into alignment with the main track where the transfer rails are held in place by latch assemblies. When the vehicle starts to leave the selected aisle and is approaching the main track, the vehicle operates trip linkages to release the latch assemblies. Continued movement of the vehicle toward the main aisle operates other linkages to pivot the transfer rails back into alignment with the aisle tracks against the influence of the biasing springs.

9 Claims, 8 Drawing Figures Patented May 1, 1973 4 Sheets-Sheet wrewroe GEORGE A. P/PEJ MATERIAL HANDLING SYSTEM This invention relates generally to a new and improved material handling apparatus and, more particularly, to a material handling system wherein a vehicle is utilized to transport materials to and from storage locations.

In automatic warehousing systems, stacker cranes and other vehicles are utilized to transport materials to and from rows of bins. In such a system, a vehicle moves along a transfer aisle until it reaches a bin aisle along which a selected bin is disposed. The vehicle then moves along this bin aisle to the selected bin. Various types of transfer arrangements have heretofore been provided to guide this movement of the vehicle from the transfer aisle to the bin aisle. However, for one reason or another, these known transfer arrangements have been somewhat unsatisfactory in their operation.

In accordance with the present invention, a pair of transfer rails are movable between a first or an initial position in which they are aligned with a transfer track which extends along a transfer aisle and a second 'or transfer position in which the transfer rails form an extension of an aisle track which guides movement of the vehicle along a bin aisle. The transfer rails, when in the initial position, guide movement of the vehicle along the transfer aisle. When the vehicle is to enter a bin aisle associated with these transfer rails, the transfer rails are pivoted in opposite directions so that they are aligned with and form an extension of tracks disposed on opposite sides of the bin aisle. This enables the transfer rails to guide movement of the vehicle into the bin aisle. When the vehicle is to leave the bin aisle, the transfer rails guide the'movement of the vehicle back into the transfer aisle. The transfer rails are then pivoted back into alignment with the transfer track to guide movement of the vehicle along the transfer aisle. The transfer rails are pivoted between the position in which they are aligned with the transfer track and the position in which they are aligned with the bin aisle tracks by arms which are mounted on the vehicle. A

transfer assembly invented by Richard J. Park and claimed in copending application Ser. No. l 17,422, filed on Feb. 22, 1971, and entitled Material Handling System Transfer Assembly" is advantageously used in association with the transfer rails so that they are pivoted back into alignment with the transfer track after a vehicle has entered a bin aisle and are automatically pivoted into alignment with the aisle tracks in the bin aisle when a vehicle is to leave the bin aisle.

Accordingly, it is an object of this invention to provide a new and improved material handling system which includes movable transfer rails for guiding movement of a vehicle between a transfer aisle and a bin aisle.

Another object of this invention is to provide a material handling system which includes a new and improved transfer arrangement for guiding movement of a vehicle from a track in a transfer aisle to a track in a bin aisle and wherein lengths of the transfer track are pivoted by the vehicle to transfer the vehicle from the one track to the other.

Another object of this invention is to provide a new and improved material handling system wherein a pair of lengths of track are pivoted by a vehicle to transfer the vehicle from one track assembly to another track assembly, the vehicle being equipped with a pair of arms to effect the pivoting movement of the lengths of track.

Another object of this invention is to provide a new and improved material handling system which includes first and second tracks extending transversely to each other for guiding movement of a vehicle along transversely extending paths and wherein a transfer rail is movable between a first position in which it is aligned with the first track and a second'position in which it is aligned with the second track, the transfer rail being movable from the first position to the second position by an operator arrangement on the vehicle to enable the transfer rail to guide movement of the vehicle along one of the tracks and then along the other.

Another object of this invention is to provide a new and improved material handling system in accordance with the next preceding object and wherein the operator arrangement on the vehicle includes an arm which is engageable with the transfer rail and a drive arrangement for moving the arm between a position extending parallel to the first track and a position extending parallel to the second track to thereby move the transfer rail between its first and second positions.

Another object of this invention is to provide a new and improved material handling vehicle for use in transporting materials along a first track and along, a second track extending transversely to the first track wherein the vehicle includes an arm arrangement for guiding movement of the vehicle along the tracks and for moving a length of track from a position in which a longitudinal axis of the length of track extends parallel to the first track to a position in which the longitudinal axis of the length of track extends parallel to the second track to thereby enable the vehicle to move along the length of track from a position in which the arm engages the first track to a position in which the arm engages the second track.

These and other objects and features of the present invention will become more apparent upon a consideration of the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a schematic illustration of a material handling system constructed in accordance with the present invention and including a vehicle which is movable from a main aisle extending transversely to a row of bins to an aisle extending along the row of bins;

FIG. 2 is a schematic illustration of a material handling vehicle constructed in accordance with the present invention;

FIG. 3 is an enlarged plan view, taken generally along line 3-3 of FIG. 2, illustrating an operator arrangement on the vehicle for use in effecting a transfer of the vehicle from a main track extending along the main aisle to aisle tracks extending along a row of bins;

FIG. 4 is an enlarged plan view of a portion of the operator assembly of FIG. 3 and illustrating the relationship of the operator assembly to a transfer arm when the transfer arm is positioned to engage an aisle track;

FIG. 5 is an elevational view, taken generally along line 5-5 of FIG. 4, illustrating the relationship of the operator assembly and transfer arm to an aisle track;

FIG. 6 is a plan view illustrating the relationship of a transfer rail to a latch assembly for retaining the transfer rail in alignment with .the main track, a trip assembly for releasing the latch assembly, and a transfer rail swing assembly for effecting movement of the transfer rail into alignment with an aisle track;

FIG. 7 is an elevational view, taken generally along line 7-7 of FIG. 6, further illustrating the relationship between the transfer rail, latch assembly, and transfer rail swing assembly; and

FIG. 8 is a plan view, generally similar to FIG. 6, illustrating the transfer rail in alignment with the aisle track.

A material handling system 10 constructed in accordance with the present invention includes a plurality of

rows

12, 14, 16, 18 and 20 of bins 22 for storing materials. Material handling vehicles 26 and 28 move along a transfer or main aisle 30 which extends perpendicular to the rows 12-20 of bins. When a material handling vehicle is adjacent to a selected bin or secondary aisle, such as the aisle 32 between the rows 14 and 16 of bins or the aisle 34 between the

rows

18 and 20 of bins, the material handling vehicle moves from the transfer or main aisle 30 down the bin or secondary aisle until it is adjacent to a selected bin. In the illustrated embodiment of the invention, the material handling vehicles 26 and 28 are stacker cranes (see FIG. 2) each of which includes a shuttle assembly 38 which is extendable to position a container 40 in a selected bin. Of course, the stacker cranes 26 and 28 can be utilized to retrieve containers, such as the container 40, from a selected bin. Although the transfer aisle 30 is referred to herein as the main aisle, it should be understood that the stacker cranes 26 and 28 perform work operations in the

bin aisles

32 and 34 which are referred to herein as secondary aisles.

The stacker crane 26 is of a known construction and rides on a cushion" of air blown against a floor or other surface 44, as is known (see FIGS. 2 and 3). Of course, other known drive arrangements could be utilized if desired and the present invention is not limited to any particular drive arrangement. The stacker crane 26 includes a rectangular frame or base 50 with an upwardly extending mast 52 which engages a track arrangement 54 on the ceiling 56 ofa building to prevent the mast from tipping. The ceiling track 54 is interrupted at the bin or

secondary aisles

32 and 34 to enable the stacker crane 26 to move from the transfer or main aisle 30 to the bin aisles.

The shuttle assembly 38 is movable vertically up and down along the mast 52 to position the container 40 vertically relative to a bin 22 which is to receive the container. Suitable power tracks can be provided adjacent either the base frame 50 or the ceiling track arrangement 54 to transmit electrical power to motors within a body 58 of the stacker crane 26. The stacker crane 28 is of the same generally known construction as the stacker crane 26 and will not be further described herein to avoid prolixity of description.

Although the stacker cranes 26 and 28 have a trackless drive directly to the floor 44, a transfer or main track 62 is engaged by the stacker cranes to guide their movement in the direction of the arrows 64 along the transfer or main aisle 30. Similarly, secondary or

aisle tracks

66, 68, 70 and 72 are disposed along the rows of bins 14-20 to guide movement of the stacker cranes 26 and 28 along the

aisles

32 and 34 in a direction perpendicular to the transfer or main aisle 30.

It should be noted that the aisle tracks 66-72 terminate just short of and do not intersect the main track 62.

In accordance with the present invention,

transfer assemblies

76 and 78 are operated by the stacker cranes 26 and 28 to guide their movement from the main track 62 to the secondary or aisle tracks 66-72 when the stacker cranes enter the

secondary aisles

32 and 34. The

transfer assemblies

76 and 78 include

transfer rails

80, 82, 84 and 86 formed of straight lengths of the main track 62. The transfer rails 80-86 normally or initially span the

secondary aisles

32 and 34 so as to guide movement of the stacker cranes 26 and 28 along the main aisle 30 past the entrances to the secondary aisles. When a stacker crane is to enter a

secondary aisle

32 or 34, the stacker crane moves into alignment with the entrance to the selected secondary aisle. The transfer rails are then moved into alignment with the tracks in the selected secondary aisle to guide movement of the stacker crane from the main aisle into this secondary aisle.

The track lengths or

transfer rails

84 and 86 are shown in FIG. 1 spanning the secondary aisle 34 to guide movement of the stacker crane 28 along the main aisle 30 past the entrance to the secondary aisle 34. On the other hand, the track lengths or

transfer rails

80 and 82 are shown pivoted from their aisle spanning positions to a transfer position in which they extend parallel to the longitudinal axis of the secondary or

aisle tracks

66 and 68 to guide movement of the stacker crane 26 from the main aisle 30 to the secondary aisle 32. Of course, once the stacker crane enters the secondary aisle 32, the aisle or

secondary tracks

66 and 68 guide movement of the stacker crane along the aisle 32, that is in the direction of the arrows 90. After the stacker crane 26 has entered the secondary aisle 32, the transfer rails 80 and 82 are advantageously pivoted back to their aisle spanning positions in which they can guide movement of the stacker crane 28 along the main aisle 30 past the entrance to the secondary aisle 32.

The stacker crane 26 includes a pair of

transfer arms

102 and 104 which engage the main track 62 and are pivotal to move the transfer rails 80 and 82 or 84 and 86 into alignment with their associated aisle tracks. The

transfer arms

102 and 104 are pivotally mounted at 106 and 108 (FIG. 3) on the frame 50 of the stacker crane 26. A drive assembly 112 is connected with the

transfer arms

102 and 104 to effect pivoting movement of the transfer arms and transfer rails engaged by the arms.

The drive assembly 112 includes a drive linkage 114 which is driven by a motor 116 (see FIGS. 4 and 5) through a gear reduction unit 118 to pivot the transfer arm 102 in a clockwise direction (as viewed in FIG. 3) about its mounting 106. Simultaneously with this movement of the transfer arm 102, the drive assembly 112 pivots the transfer arm 104 in a counter clockwise direction (as viewed in FIG. 3) about its mounting 108. Since the transfer rails 80 and 82 are engaged by the

arms

102 and 104, this pivotal movement of the arms moves the transfer rails 80 and 82 from their aisle spanning positions extending across the secondary aisle 32 to their transfer positions extending parallel to the aisle tracks 66 and 68 (see FIG. 1). Thus, the

transfer arms

102 and 104 are pivotal from positions extending outwardly of the stacker crane 26 to positions beside the frame 50 of the stacker crane to move the transfer rails 80 and 82 into alignment with the aisle tracks 66 and 68. However, it should be understood that the

transfer arms

102 and 104 could be mounted for movement from a position extending along the front of the frame 50 to an outwardly extending position to pivot the transfer rails 80 and 82 into alignment with the aisle tracks 66 and 68. In addition, it should be understood that although a pair of

transfer arms

102, 104 have been illustrated herein to pivot a pair of relatively short transfer rails 80 and 82, a single transfer arm could be mounted on the stacker crane 26 to pivot a single relatively long transfer rail.

The

transfer arms

102 and 104 are held in a position extending parallel to the longitudinal axis of the main track 62, that is in the position of transfer arms 122 and 124 of the stacker crane 28 in FIG. 1, by a pair of struts 128 and 130 (FIG. 3). The struts 128 and 130 are pivotally connected at 134 and 136 to outer end portions of the

transfer arms

102 and 104. The inner end of the strut 128 is pivotally connected at 138 to a slide block 140 which is movable along a channel 142 defined between a pair of

guides

144 and 146 mounted on the frame 50. The inner end portion of the strut 130 is connected to the frame 50in the same manner as in which the strut 128 is connected with the frame.

When the stacker crane 26 is moving along the main track 62 with the

transfer arms

102 and 104 extending parallel to the longitudinal axis of the main track, the transfer arms interconnect the stacker crane and the main track. Since the main track 62 guides movement of the stacker crane 26 along the main aisle 30, it is important that the

transfer arms

102 and 104 be held against pivotal movement relative to the frame 50 of the stacker crane. Accordingly, a latch assembly 154 engages the slide block 140 to retain the strut 128 against movement along the channel 142. When the transfer arm 102 is to be pivoted inwardly toward the frame 50 of the vehicle by operation of the drive assembly 112, a release solenoid 156 on the frame 50 is energized to operate the latch assembly 154 and release the slide block 140 for movement along the channel 142 in the direction of the arrow 160. This enables the transfer arm 102 to be pivoted in a clockwise direction toward the frame 50 of the stacker crane 26 by the drive assembly 112, Of course, a latch assembly and solenoid similar to the latch assembly and

solenoid

154 and 156, are associated with the strut 130 to hold the transfer arm 104 against pivotal movement when the stacker crane 26 is moving along the main track 62.

The drive assembly 112 is operable to simultaneously pivot the

transfer arms

102 and 104 and the transfer rails 80 and 82 through ninety degrees relative to the frame 50 of the stacker crane 26. Accordingly, the linkage 114 of the drive assembly 112 includes a swivel plate 170 which is rotatable relative to the frame 50 by a drive or output shaft 172 (FIGS. 3, 4 and 5) of the gear reducer 118. Rotational movement of the swivel plate 170 moves pivot

arms

176 and 178 to rotate crank

arms

180 and 182 through 90". Of course, this rotational movement of the

crank arms

180 and 182 pivots support

pins

184 and 186 which are connected to the

transfer arms

102 and 104. The inner-connection between the support pin 184 and the transfer arm 104 includes a connector plate 190 (FIG. 5) which is fixably connected to the transfer arm 104 and the support pin 184. Although only the mounting for the transfer arm 104 on the support pin 184 is illustrated herein, it should be understood that the transfer arm 102 is mounted on the support pin 186 in the same manner.

From the foregoing, it can be seen that the stacker crane 26 includes a pair of

transfer arms

102 and 104 which extend parallel to and engage the main track 62 with rollers, similar to

rollers

196 and 198 of FIG. 5, to guide movement of the stacker crane along the main aisle 30. When the stacker crane 26 reaches the entrance to a selected secondary aisle, such as the aisle 32, the

transfer arms

102 and 104 are pivoted through 90 toward the frame of the stacker crane by the drive assembly 112. This movement of the

transfer arms

102 and 104 pivots the transfer rails 80 and 82 into alignment with the aisle tracks 66 and 68. When the transfer rails 80 and 82 have been pivoted into alignment with the aisle tracks 66 and 68, the stacker crane is moved forward along the aisle 32. As the stacker crane 26 moves along the aisle 32, the rollers on the

transfer arms

102 and 104 move out of engagement with the transfer rails 80 and 82 and into engagement with the aisle tracks 66 and 68. Although the

transfer arms

102 and 104 have been described herein in connection with the stacker crane 26, it is contentplated that they could be used in association with other types of material handling vehicles.

A separate transfer rail swing or operator assembly is advantageously associated with each of the pivotal transfer rails 80-86 to move the associated transfer rail between the initial position and the transfer position. Thus, a transfer rail swing or operator assembly 210 (see FIGS. 6, 7 and 8) is associated with the transfer rail 82 to effect movement of the transfer rail between the initial position in which it is aligned with the main track 62 (FIGS. 6 and 7) and a second or transfer position in which the transfer rail 82 is aligned with the aisle track 68 (FIG. 8). As was previously explained,the

transfer arms

102 and 104 on the stacker crane 26 pivot the transfer rail 82 from its initial position in which it forms part of the main track 62 to the transfer position in which it is aligned with the aisle track 68. However, the swing or operator assembly 210 pivots the transfer rail 82 back into alignment with the main track 62 once the stacker crane 26 has entered the secondary aisle 32. This enables the transfer rail 82 to guide movement of another stacker crane, for example, the stacker crane 28, along the main aisle 30 while the stacker crane 26 is in the secondary aisle 32. When the stacker crane 26 approaches the main aisle 30 to leave the secondary aisle 32, the transfer rail swing or operator assembly 210 pivots the transfer rail 82 back into alignment with the aisle track 68 to enable the transfer rail 82 to guide movement of the stacker crane 26 as it returns to the main aisle 30.

The transfer rail 82 is held or retained'in alignment with the longitudinal axis of the main track 62 by a latch assembly 214 which is mounted on a support frame 216 extending along the main aisle 30. The latch assembly 214 includes a retaining latch or pawl 220 which is pivotally mounted on the support frame 216 for movement between an engaged or latched position and a release position. When it is in the latched position, the latch pawl 220 engages the rail 82 to hold the rail against pivotal movement relative to the main track 62. When the latch pawl 220 is released, a retaining nose or end portion 222 of the latch pawl is raised upwardly (from the position shown in FIG. 7) to clear the transfer rail 82 so that it is free to move into alignment with the aisle track 68 (see FIG. 8).

As the stacker crane 26 moves along the main track 62 into alignment with the entrance to the secondary aisle 32, the latch pawl 220 is pivoted upwardly by camming engagement of the transfer arm 104 with the nose 222 of the latch pawl. This releases the latch assembly 214. The transfer arm 104 is then moved inwardly toward the frame 50 of the stacker crane 26 by operation of the drive assembly 112 in the manner previously explained. Since the

rollers

196 and 198 engage the transfer rail 82 (FIG. this movement of the transfer arm 104 pivots the transfer rail 82 in a counter clockwise direction (as viewed in FIG. 6) about a pivot mounting 230. This results in the transfer rail 82 moving out of alignment with the main track 62, through the position shown in FIG. 3, and to the transfer position (FIG. 8) in which the transfer rail is aligned with the aisle track 68. Of course, the transfer rail 80 is pivoted simultaneously with the transfer rail 82 by the transfer arm 102 of the stacker crane 26 (FIG. 3).

Once the transfer rails 80 and 82 have been moved into alignment with the aisle tracks 66 and 68, the stacker crane 26 can enter the aisle 32. It should be noted that the stacker crane 26 moves along the main aisle 30 in a direction parallel to its transverse axis 231 (see FIG. 1) and then moves along the secondary aisle 32 in a direction parallel to its longitudinal axis 232. However, the

transfer arms

102 and 104 engage guide tracks to guide movement of the stacker crane 26 along either the main aisle 30 or the secondary aisle 32. Thus, the

transfer arms

102 and 104 extend parallel to the axis 231 and the main track 62 when the stacker crane 26 is moving along the main aisle 30. Similarly, when the stacker crane 26 is moving along the secondary aisle 32, the

transfer arms

102 and 104 extend parallel to the longitudinal axis 232 of the stacker crane and engage the aisle tracks 66 and 68 -to guide movement of the stacker crane along these tracks.

Once the stacker crane has entered the secondary aisle 32 and has moved a short distance beyond the transfer rail 82, a biasing spring 240 pivots the transfer rail from the transfer position of FIG. 8 to the initial position of FIG. 6. The biasing spring 240 extends between a stationary support bracket 242 and a crank arm 244 which is connected to the pivot mounting 230 for the transfer rail 82. When the transfer rail 82 is pivoted from the initial position to the transfer position immediately prior to entrance of the stacker crane 26 into the secondary aisle 32, the crank arm 244 is pivoted in a counter clockwise direction from the position shown in FIG. 6 to the position shown in FIG. 8 with a resulting stretching of the biasing spring 240. Therefore, when the trailing end of the stacker crane 26 has moved a short distance beyond the transfer rail 82, the biasing spring 240 pivots the crank arm 244 and transfer rail 82 in a clockwise direction about the pivot mounting 230 to move the transfer rail into alignment with the main track 62. Of course, the latch assembly 214 will then engage the transfer rail 82 to retain it in alignment with the main track 62.

When the stacker crane 26 leaves the aisle 32, the transfer rail 82 must be swung or pivoted out of alignment with the main track 62 and into alignment with the aisle track 68 to guide movement of the stacker crane out of the aisle 32. Accordingly, when the stacker crane 26 approaches the main aisle 30, a trip assembly 250 is actuated to operate the latch assembly 214 and release the transfer rail 82 for movement about the pivot mounting 230. Continued movement of the stacker crane toward the main aisle 30 actuates a swing operator assembly 252 to effect pivotal movement of the transfer rail 82 from the initial position (FIG. 6) to the transfer position shown (FIG. 8). Thus, the transfer rail 82 is moved from a position in which it is aligned with the main track 62 (FIG. 6) to a position in which it is aligned with the aisle track 68 (FIG. 8) against the influence of the biasing spring 240 in response to movement of the stacker crane 26 along the aisle 32 toward the main aisle 30.

The trip assembly 250 for releasing the latch assembly 214 includes a trip arm 258 which is pivotally mounted on a support bracket 260 and is movable to the actuated position of FIG. 8 to release the latch assembly 214. The trip arm 258 is connected with the latch assembly 214 by a flexible cable 262. The flexible cable 262 is in turn connected to a latch trip plate or bar 266 (FIG. 7) which is pivotally mounted at 268 on a support bracket 270. The trip plate or bar 266 is connected with the latch pawl 220 by a link 274.

When the stacker crane 26 moves along the aisle 32 toward the main aisle 30, the stacker crane engages the trip arm 258 which extends into the aisle 32 (see FIG. 6). Continued movement of the stacker crane 26 toward the main aisle 32 pivots the trip arm 258 to its actuated position (FIG. 8). Moving the trip arm 258 to its actuated position causes the cable 262 to rotate the trip plate 266 in a clockwise direction (as viewed in FIG. 7) about its pivot mounting 268. This rotational movement of the trip plate 266 is transmitted by the link 274 to the latch pawl 220 to thereby rotate the latch pawl in a counter clockwise direction (as viewed in FIG. 7) about its pivot mounting 280 against the influence of a biasing spring 282. This pivotal movement of the latch pawl 220 releases the transfer rail 82 for pivoting movement-from its initial position (FIG. 6) to the transfer position (FIG. 8).

Still further movement of the stacker crane toward the main aisle 30 results in the swing or operator assembly 252 being actuated by the stacker crane to pivot the transfer rail 82 from the initial position to the transfer position against the influence of the biasing spring 240. Thus, the operator assembly 252 includes a swing bar 286 which is pivotally mounted at 288 on a generally V-shaped support bracket 292. The support bracket 282 includes a pair of legs 294 and 296 (see FIGS. 6, 7 and 8) which are connected to a mounting plate 300 secured to the aisle track 68. A trip or actuator arm 304 is pivotally mounted at 306 on the swing arm 286 and is biased against a detent or stop 308 by a spiral spring 312. This mounting enables the actuator arm 304 to move the swing arm 286 in only a clockwise direction about the pivot mounting 288.

When a leading end portion of the stacker crane 26 engages the actuator arm 304 as it moves toward the main aisle 30, the actuator arm causes the swing or operator bar 286 to pivot in a clockwise direction (as viewed in FIG. 6) to the actuated position shown in FIG. 8. This pivotal movement of the swing or operator bar 286 is transmitted to the crank arm 244 by a connector rod 316 to rotate the crank arm 244 and transfer rail 82 through90" from the initial position (FIG. 6) to the transfer position (FIG. 8) against the influence of the biasing spring 240.

Once the transfer rail 82 has been moved to the transfer position, continued movement of the stacker crane 26 toward the main aisle 30 moves rollers 318 (FIG. 2) out of engagement with the aisle track 68 and into engagement with the transfer rail 82. Continued movement of the stacker crane 26 toward the main aisle 30 moves the

rollers

196 and 198 on the transfer arm 104 into engagement with the transfer rail 82 (FIG. 5)v Once the stacker crane 26 has moved into the main aisle 30 (FIG. 1), the transfer arms I02 and 104 on the stacker crane 26 are pivoted to move the transfer rails 80 and 82 from the transfer positions (FIG. 1) to their initial positions spanning the aisle 32. As the transfer rails 80 and 82 are swung into their initial positions by the transfer arms 104, the transfer rails will be engaged by latch assemblies, similar to the latch assembly 214 (FIG. 7). This retains the transfer rails 80 and 82 against pivotal movement as the stacker crane 26 moves along the main track 62. Once this has occurred, the stacker crane 26 is free to move along the main aisle 30 in the direction of the arrows 64.

Although only the transfer rail swing or operator assembly 210 associated with the transfer rail 82 has been fully described herein, it should be understood that a similar operator assembly is associated with the transfer rail 80. Therefore, the transfer rails 80 and 82 are moved together in unison by their associated operator assemblies to swing the transfer rails back to their initial positions spanning the aisle 32 once the stacker crane 26 has entered the aisle 32. In addition, the transfer rail 80 is swung to its transfer position (see FIG. 1) by operation of a swing or operator assembly of the same construction as the swing operator assembly 252, at the same time that the transfer rail 82 is swung tov its transfer position. In addition, it should be understood that transfer rail swing or operator assemblies, of the same construction as the transfer rail swing assembly 210 of FIG. 8, are associated with the transfer rails 84 and 86 to move them in the same manner as previously explained in connection with the transfer rails 80 and 827 In view of the foregoing remarks, it can be seen that the material handling system 10 includes a main track 62 for guiding movement of the stacker cranes 26 and 28 in the direction of the arrows 64. Transfer rails 80, 82, 84 and 86 are mounted in pairs in association with the

secondary aisles

32 and 34. The transfer rails are pivotal between an initial position in which they are aligned with the main track 62 and a transfer position in which they are aligned with the associated aisle tracks 66, 68, 70 and 72. When a stacker crane, such as the stacker crane 26, is to move from the main aisle to a secondary aisle, the stacker crane is aligned with the entrance to the aisle and the

transfer arms

102 and 104 on the stacker crane are pivoted to swing the transfer rails into alignment with the aisle tracks. The stacker crane 26 then moves down the secondary aisle.

When the stacker crane 26 has cleared the swing or pivot arm 286 of the transfer rail swing assembly 210, the biasing spring 240 will swing the associated transfer rail back into alignment with the main track 62.

When the stacker crane 26 is to leave the secondary aisle, the stacker crane operates the latch assembly 250 to release the latch 214. The stacker crane 26 then actuates the swing or operator assembly 252 to pivot the associated transfer rail about the pivot mounting 230 into alignment with the aisle track 62, Once the stacker crane 26 has moved into the main aisle 30, the

transfer arms

102 and 104 on the stacker crane are operated to swing the transfer rails and 82 back to their aisle spanning positions so that the stacker crane is free to move along the main aisle. Although only the

transfer arms

102 and 104 for the stacker crane 26 have been fully describedherein, it should be understood that the transfer arms 122 and 124 on the stacker crane 28 are of the same construction and operate in the same manner as do transfer

arms

102 and 104.

Having described specific preferred embodiments of the invention, the following is claimed:

1. A material handling apparatus comprising a vehicle for use in moving materials; first and second track means extending transversely to each other for guiding movement of said vehicle along transversely extending paths; a length of track movable between a first position in which it is aligned with said first track means and a second position in which said length of track is aligned with said second track means; and means on said vehicle for effecting movement of said length of track from said first position to said second position to enable said length of track to guide movement of said vehicle along one of the paths and then along the other of the paths including an arm movably mounted on said vehicle and engageable with said length of track, and drive means on said vehicle for moving said arm between a position extending parallel to said first track means and a position extending parallel to said second track means to move said length of track between its first and second position.

2. A material handling apparatus as set forth in claim 1 wherein said first and second track means extend perpendicular to each other and have longitudinal axes disposed in a common horizontal plane, said system further including mounting means for supporting said length of track for pivotal movement from said first position through ninety degrees about a vertical axis to said second position.

3. A material handling apparatus as set forth in claim 1 wherein said second track means terminates short of a point of intersection with said first track means, said length of track extending from the termination of said second track means through the point where said first track means would intersect said second track means when said length of track is in said second position.

4. A material handling apparatus comprising a vehicle for use in transporting materials along a first track and along a second track extending transversely to the first track, said vehicle comprising a frame and arm means mounted on said frame for engaging the tracks to guide movement of said vehicle along the tracks and for moving a length of track from a first position in which a longitudinal axis of the length of track extends parallel to a longitudinal axis of said first track to a second position in which a longitudinal axis of the length of track extends parallel to a longitudinal axis of said second track to thereby enable the vehicle to move along the length of track from a position in which said arm means engages the first track to a position in which said arm means engages the second track.

5. A material handling apparatus as set forth in claim 4 further including drive means for effecting movement of said arm means from one position in which said arm means extends parallel to the longitudinal axis of the first track to another position in which said arm means extends parallel to the longitudinal axis of said second track to thereby effect movement of the length of track between the first and second positions.

6. A material handling apparatus as set forth in claim 4 wherein said arm means includes a first arm pivotally mounted on one side of said vehicle and a second arm pivotally mounted on another side of said vehicle, said vehicle further including drive means for moving said first and second arms from a position in which longitudinal axes of said arms are coincident with each other and extend parallel to a longitudinal axis of said first track to a second position in which the longitudinal axes of said arms are spaced apart and extend parallel to the longitudinal axis of said second track.

7. A material handling apparatus comprising a material handling vehicle, first track means for guiding movement of said vehicle along a main aisle, a plurality of second track means each of which extends along an associated one of a plurality of secondary aisles, said second track means terminating short of intersection with said first track means, said first track means including a plurality of pairs of lengths of track, each pair of which is movable between a first position spanning an associated one of said secondary aisles to guide movement of said vehicle along the main aisle past the associated secondary aisle and a secorid position forming an extension between the associated one of said second track means and said first track means to guide movement of said vehicle from the main aisle into the associated secondary aisle, and means on said vehicle for effecting movement of said pairs of lengths of track from their first position to their second position.

8. A material handling apparatus as set forth in claim 7 wherein said means on said vehicle for effecting movement of said pairs of lengths of track includes means for pivoting one length of track of a pair of lengths of track in a clockwise direction about a first axis and means for pivoting the other length of track of the pair of lengths of track in a counterclockwise direction about a second axis.

9. A material handling apparatus as set forth in claim 8 wherein said means for pivoting said lengths of track includes a first arm pivotally mounted on the vehicle and engageable with the one length of track and a second arm pivotally mounted on the vehicle and engageable with the other length of track and drive means on the vehicle for simultaneously pivoting said first and second arms in opposite directions relative to the vehicle to move a pair oflengths of track from the first position to the second position.

Claims

7. A material handling apparatus comprising a material handling vehicle, first track means for guiding movement of said vehicle along a main aisle, a plurality of second track means each of which extends along an associated one of a plurality of secondary aisles, said second track means terminating short of intersection with said first track means, said first track means including a plurality of pairs of lengths of track, each pair of which is movable between a first position spanning an associated one of said secondary aisles to guide movement of said vehicle along the main aisle past the associated secondary aisle and a second position forming an extension between the associated one of said second track means and said first track means to guide movement of said vehicle from the main aisle into the associated secondary aisle, and means on said vehicle for effecting movement of said pairs of lengths of track from their first position to their second position.

9. A material handling apparatus as set forth in claim 8 wherein said means for pivoting said lengths of track includes a first arm pivotally mounted on the vehicle and engageable with the one length of track and a second arm pivotally mounted on the vehicle and engageable with the other length of track and drive means on the vehicle for simultaneously pivoting said first and second arms in opposite directions relative to the vehicle to move a pair of lengths of track from the first position to the second position.