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Publication numberUS3762589 A
Publication typeGrant
Publication dateOct 2, 1973
Filing dateDec 16, 1971
Priority dateDec 16, 1971
Publication numberUS 3762589 A, US 3762589A, US-A-3762589, US3762589 A, US3762589A
InventorsShaffer W
Original AssigneeTownmotor Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Ultra-narrow-aisle lift truck
US 3762589 A
An apparatus and method in the form of a vehicle for transporting, lifting, placing and retrieving loads in narrow-aisle load storage racks. Narrow-aisle operation is provided by vertically movable, extensible tracks which enter the load space and rest upon the racks thus permitting a track-mounted carriage having lift forks thereon to enter and leave a load space.
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Description  (OCR text may contain errors)

United States Patent [1 1 Shaffer Oct. 2, 1973 I 1 ULTRA-NARROW-AISLE LIFT TRUCK [75] Inventor: Walter M. Shaffer, Chesterland,


[73] Assignee: Townrnotor Corporation, Cleveland,


[22} Filed: Dec. 16, 1971 121] App]. No.: 208,576

[52] US. Cl. 214/730, 104/127 [51] Int. Cl B661 9/14 [58} Field of Search 214/730, 16.4 A, 214/38 D; 104/48,127, 131

[56] References Cited UNITED STATES PATENTS 3,233,768 2/1966 Turturro et a1. 214/730 3,357,582 12/1967 Wittek 214/512 9/1935 Becker 214/61.1 CB

1,880,374 10/1932 Dahlstrom 214/730 2,915,204 12/1959 Alimanestianm.v 21 1/6114 A 3,643,825 2/1972 Zane, Jr. 1 214/730 3,606,039 I 9/1971 Weston et a1 1. 214/16.4 A 3,143,081 8/1964 Dolphin et a1. 214/730 Primary Examiner-Gerald M. Forlenza Assistant Examiner-Lawrence J. Oresky Att0rney-Martin Majestic [57] ABSTRACT An apparatus and method in the form of a vehicle for transporting, lifting, placing and retrieving loads in narrow-aisle load storage racks. Narrowais1e operation is provided by vertically movable, extensible tracks which enter the load space and rest upon the racks thus permitting a track-mounted carriage having lift forks thereon to enter and leave a load space.

7 Claims, 15 Drawing Figures PMENIEW 2W 3,752,589


INVENTOR WALTER M. S HAFFEF ATTORNEYS ULTRA-NARROW-AISLE LIFT TRUCK BACKGROUND OF THE INVENTION It has long been a problem in the storage and other industries to maximize the usage of available storage space without resorting to high-cost, limited-use equipment installations. Industry is presently attempting to solve this problem through several approaches.

One such approach has been to use lift trucks with a reach-type, pantograph carriage mechanism that is designed to extend into a second storage space, thus reducing the number and width of aisles from that required by a standard fork-lift truck. Another approach uses straddle trucks which have extending arms to straddle and support the load and which, like the standard truck, must make a 90 turn from the aisle and enter the load storage space to deposit or retrieve a load. Both the reach-type truck and the straddle truck require fouror five-foot wider aisles than the load being carried which is obviously wasteful of available storage space.

Another approach that is more of a single-purpose nature and consequently much more expensive is using a stacker crane, which normally works from an overhead rail. This requires that it be built into the warehouse design. The stacker crane requires a working aisle width two or three feet wider than the loads being handled.

A still further industry approach to the problem is the use of an automatic warehousing system, wherein a computer provides data storage and is interconnected with an automated storage-retrieval mechanism similar to the stacker crane. This later system is costly and is usually very difficult to adapt to an existing warehouse facility.

SUMMARY OF THE INVENTION The present invention overcomes the above-noted problems by providing an apparatus and method in the form of an extremely narrow-aisle lift truck that makes more efficient use of warehousing and storage space by requiring an aisle only slightly wider than the load itself. This is a major economic advantage since the aisle space saved can be put to productive use as load storage space. This subject lift trucks load moment is primarily within its wheel plan, and this fact coupled with the elevated load and mechanism being closely contained and partially supported by the warehouse racks, providesa lift truck which is highly resistant to tipping even when the load is in its highestextended position.

Another feature provides for the operator riding up with the load, thus providing him with excellent visibility for a more efficient and safe operation.

Added to its usefulness in narrow-aisle rack storage of unit loads, this invention will also be an effective or der-picker. Furthermore, by not requiring a 90 turn from the aisle into the stack to store or retrieve the load, as is necessary with present narrow-aisle lift trucks, this invention is adaptable to varyingdegrees of automatic control.

Since a significant load moment is not applied to the load-handling mechanism other than within the traveling carriage, relatively small structural members are used, thus greatly reducing the cost of manufacturing and further increasing the vehicle's efficiency.

OBJECTS OF THE INVENTION Accordingly, it is a primary object of this invention to provide a lift truck that will operate in an aisle no more than one foot wider than the load being transported, thus making maximum use of expensive warehouse and storage yard space.

Another object of this invention is to accomplish the above by containing the major portion of the load moment within the wheel plan of the lift truck, thus making use of relatively small and inexpensive structural members, and further reducing vehicle cost as well as increasing vehicle efficiency through the reduction of unproductive vehicle weight.

Also, it is an object of this invention to provide a lift truck whose load moment is so placed as to allow ex tremely high lifts in a safe manner.

It is a further object of this invention to provide a lift truck having extensible tracks for supporting the load during deposit and retrieval and also having safety means precluding operation unless the tracks are fully supported.

It is a further object to provide a vehicle whereby the operator rides up with the load, thus assuring excellent visibility and a highly efficient and safe operation.

A further object of this invention is to provide a more versatile lift truck that will be adaptable to varying degrees of an automated-control warehousing system.

Additional advantages and features of the present invention are made apparent in the following description and the accompanying drawings, wherein:

\ FIG. 1 is a perspective view of the invention, from the operator platform side, showing the carriage assembly and operator platform in its highest, raised position;

FIG. 2 is a top plan view of the invention;

FIG. 3 is a side elevation view partially cut away to show the operating mechanism for providing small incremental movement of the forks relatve to the major carriage member;

FIG. 4 is a front elevation of the invention showing the tracks fully extended;

FIG.'5 is a cross-sectional view taken as shown in FIG. 2;

FIG. 6 is a cross-sectional view of the carriage guide rail as shown in FIG. 4;

FIG. 7 is a similarview of the carriage guide rail, as shown in FIG. 4; and

FIGS. 8-15 are schematic drawings setting forth a sequence of load handling operations.

DETAILED DESCRIPTION Referring now in detail to FIGS. 1-3 of the drawings, the inventive lift truck generally at 10 comprises a body portion 12 containing power and control components (not shown). The power source may consist of batterypowered electric motor means, an internal combustion engine coupled through a mechanical or hydrostatic drive means to the single steerable drive wheel 14, or such other. motive power means or combination of means known to those well skilled in the art.

A transverse, forward frame member 16 is joined to the body portion 12 by means of a longitudinal side frame member 18. Forward and aft mast assemblies 20 and 22 with their associated carriages 24 and 26, respectively, are provided for vertical positioning of the load carriage means. Mast assembly 22 is mounted on body portion 12, while mast assembly 20 is mounted on the forward frame member 16. The two forward nonsteerable wheels 28 are also secured at each end of the forward frame member 16, by conventional axle suspension means (not shown).

Four guide rollers 30 at the four corners of the vehicle are spaced at the correct width and height to properly mate with the warehouse longitudinal rack members 32, thus providing additional guidance for the lift truck when it is traversing the storage aisles. Steering of the powered wheel 14 is accomplished by means of a manually operable steering wheel 34 with its columnmounting integral with the rigid body portion 12.

The operator station 36 contains all other controls (not shown) and moves with the stationary transverse track sections 38 and the movable carriage assembly 40, thus permitting the operator compartment 12 to move vertically with the load handling portion of the truck, shown generally at 42. It is understood that alternatively the steering wheel could also move vertically with the operator station or compartment.

The carriage assembly 40 has mounted thereon a pair of forks 44 and 46 for supporting the load 48 to be transported, and forms a traversing unit 50 in combination with the side members 52 and 54. Each side member contains a pair of rollers 56 mounted in recesses on its underside, for engaging the track section members 38.

As shown in FIG. 3, a pair of hydraulic jacks 58 and 60 in combination with bellcrank linkages 62, 64, permit a limited amount of vertical movement for raising and lowering the load independently of the carriage lift mechanism, with such movement being necessary to raise or lower the load to the warehouse racks or floor without moving the guide tracks. Stationary transverse track sections 38 serve to support both the load carriage and the two sections of folding transverse track members 66 and 68, all having the same top contour. The folding track sections 66 are pivotally joined to carriage members 38 by a rotary hinge means 70, and the folding track section 66 is pivotally joined to the track member 68 by rotary hinge means 72.

Turning now to FIG. 5, the track extension sequence, from traveling position to load/unload position, will be described. Operator activation of the hydraulic jack means 74, causes the folding track member 66 to rotate clockwise and assume position 66'. At the same time, folding track member 66 rotates clockwise, folding track member 68 rotates counterclockwise to assume its position 68.

Thus, the lower surfaces of the transverse folding track members 66 and 68 will have engaged the warehouse storage space floor as shown in FIG. 4, or, if the carriage lift member 40 is in the upper position, as shown in FIGS. 12-15, said track members will rest upon the warehouse rack assembly 76 supported by members 78 and 80.

Returning to FIG. 5, the mechanism for extending the track sections includes a link member 82 which is pivotally attached at one end at pivot means 84 on the track members 38 and is guided by the internal walls of of hollow track sections 66. A support roller means 86 is attached to the other end of link 82. As best seen in FIG. 4, roller means 86 rolls against the surface 88 on the underside of folding track assembly 68 allowing it to move smoothly from its vertical traveling position 68 to its horizontal load/unload position. The sequence of operation is reversed for folding the track back into its traveling position.

When the truck is in the load/unload condition and the track is horizontally extended into the warehouse storage space, a smooth, continuous load-support track is presented for the subsequent transverse movement of the traversing unit 50.

Turning to FIGS. 5-7, it may be seen that rollers 56 conform to the contoured upper surface of track members 38, 66 and 68. The rollers 56 are mounted on the bottom of the carriage side members 52 and 54, and have a fixed scraper member 90 in front and behind the rollers 56 to clear debris from the track top surface, thus always presenting a clean, smooth track surface to the rollers.

As best seen in FIG. 2, the transverse movement of the carriage assembly or traversing unit 50 and load 48 is provided by chains 92 and 94 attached to side members 52, 54, chain sprockets 96, and chain guides 98 attached to transverse track sections 38 by conventional means (not shown). A very small rotary hydraulic motor means, or other such motor means readily known to one skilled in the art, is used to drive the chain sprocket mechanism thereby propelling the carriage and load onto the track sections 66 and 68. The carriage forks vertical movement is then actuated through hydraulic jacks 58 and 60 and bellcranks 62 and 64 as best seen in FIG. 3 to deposit the load on the warehouse rack or floor.

As seen in FIG. 4, a safety feature is also included whereby the chain drive sprocket motor means cannot be energized if the folding track members 66 and 68 are not in a safe, supported position on the warehouse floor or rack. This is accomplished by means of a plunger 100, located in the lower surface of the outer track member 68, which is depressed by either the warehouse floor or warehouse rack assembly 76 and thereby actuates a safety switch mechanism (not shown) connected to the chain sprocket motor means.

The method of operation of my invention will now be described with particular reference to FIGS. 8-15 of the drawings. The first step is shown in FIG. 8 wherein lift truck 10 is driven in a storage aisle to a point adjacent to a load 48, which load is contained in a load storage space defined by top rack assembly 76 and members 78 and 80. As shown in FIG. 9, the next step is the extension of folding track sections 66, 68 into the load space, with one of each pair of track sections resting on the ground on either side of load 48.

The next step, shown in FIG. 10, is to propel the traversing unit or carriage into the load space on the track sections by chain means (not shown). It may be parenthetically noted that the load moment on the vehicle is minimized due to the ability of the track sections to transmit much of the weight of the load to the supporting ground at their point of contact therewith. Actuation of fork means (not shown) is then accomplished to lift the load from its supporting surface whereupon the chain means is reversed to retract the traversing unit and load into the vehicle to the position shown in FIG. 1 l.

The track members are then retracted for subsequent movement of the vehicle.

If a higher load space is to be serviced, the load handling portion 42 of the truck including the operator station is raised by activating the lift mast means 102 as shown in FIG. 12. The above steps are then repeated as shown in FIGS. 13-15, however, reversing the steps to deposit the load.

One embodiment of my invention has been fully described, but it will be apparent to anyone skilled in the art that various other forms would be possible without departing from the spirit of the invention or the scope of the following claims.

What is claimed is:

l. A lift truck for use in narrow storage aisles comprising,

a body,

a pair of track members pivotally attached, to the body by pivot means, said track members being extendible so as to enter an adjacent load space,

means forextending said track members,

carriage means including lift fork means thereon adapted for raising and lowering loads,

means for propelling said carriage means on said track members into an adjacent load space for retrieving or depositing loads,

safety means rendered operative by extending said track members into supporting contact with a support surface for preventing propelling of the carriage means when the track means is not fully supported.

2. The lift truck of claim 1 further including mast means for raising and lowering said track means whereby higher load spaces can be accommodated.

3. The lift truck of claim 1 wherein the means for propelling the carriage means comprises chains and sprockets mounted on the track means.

4. The lift truck of claim 1 wherein the lift fork means comprises hydraulic cylinder means operatively connected to a pair of lift forks by linkage means.

5. The lift truck of claim 1 wherein the means for extending said track members comprise hydraulic jacks operatively connected to said track members for movement thereof.

6. The lift truck of claim 1 further including an operator platform operatively connected to said track means for vertical movement therewith whereby enhanced operator visibility is provided.

7. The lift truck of claim 1 further including a plurality of guide wheels mounted on said body for facilitating negotiation of narrow aisles by the lift truck.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- 3,762,589 Dated October 2, 1973 Inventor M It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading:

"Townmotor" should read --Towrriotor--.

Columh 1, line 16 "dard truck" should read -dard fork lift truck--.

4 Signed and sealed this 30th day of April 19%..

(SEAL) Attest:

EDwAl-ZD I-LrLETCIiElQJH. C. I lARSHALIJ DAL-IN A'btestiz'lg Officer Commissioner of Patents FQRM Po-1o5o (10 59)

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3972434 *Dec 23, 1974Aug 3, 1976Allis-Chalmers CorporationOrder picker with operator's platform on the front end of the load support
US3977550 *Nov 18, 1974Aug 31, 1976Towmotor CorporationSide handling attachment
US6648581 *Jul 2, 2001Nov 18, 2003The Raymond CorporationOrder picker truck
US8257008 *Mar 19, 2007Sep 4, 2012Walgreen Co.Warehouse loader
U.S. Classification414/664, 104/127
International ClassificationB66F9/12, B66F9/14
Cooperative ClassificationB66F9/14
European ClassificationB66F9/14