WO2005095235A1

WO2005095235A1 - Compact pushback storing system for pallets

Info

Publication number: WO2005095235A1
Application number: PCT/CA2005/000483
Authority: WO
Inventors: Yves Fourage
Original assignee: Developpements Matex Inc.
Priority date: 2004-03-30
Filing date: 2005-03-30
Publication date: 2005-10-13
Also published as: CA2462929A1

Abstract

A compact pushback storage system for storing pallets in rows of shelves defining lanes. The system includes a first pair of rails running from front to back in each lane. Each rail has inboard and outboard side edges for receiving wheels to roll upon the edges. The system also includes a set of four carts having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the inboard and outboard side edges of each rail.

Description

COMPACT PUSHBACK STORING SYSTEM FOR PALLETS

FIELD OF THE INVENTION

The present invention relates to an improvement in a pushback storing system designed to store large numbers of packages or cartons on racks or shelving by means of pallets.

BACKGROUND OF THE INVENTION

Pushback storing systems have long been sought out by operators of storage warehouses. Its storage principle allows the use of conventional fork lift trucks. The trucks do not penetrate inside the structure, as opposed to drive-in systems, therefore it saves time and the handling of a single pallet for storage or removal does not exceed eight seconds.

The surface of a typical warehouse can be divided by two when using a pushback storage system, which is economically important. In the industry, one can estimate that one out of five applications could use the concept of pushback storage systems.

Known in the art, there is US patent No. 5,393,188 (SCOTT) which discloses a pushback storage system for pallets. However, the design that is used does not allow to have more than three carts per each pair of rails. In order to add a fourth cart for example, a second pair of rails must be used, which increases costs.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a compact pushback storage system for storing pallets in rows of shelves defining lanes, the system comprising: a first pair of rails running from front to back in each lane, each rail having inboard and outboard side edges for receiving wheels to roll upon the edges; a first cart having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the outboard side edge of each rail; a second cart adapted to move along the lane and extending below relative to the first cart, the second cart having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the outboard side edge of each rail, the back wheels of the second cart being positioned backwards of the front wheels of the first cart; a third cart adapted to move along the lane and extending below relative to the first and second carts, the third cart having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the inboard side edge of each rail, the back wheels of the third cart being positioned backwards of the front wheels of the second cart; and a fourth cart adapted to move along the lane and extending below relative to the first, second and third carts, the fourth cart having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the inboard side edge of each rail, the back wheels of the fourth cart being positioned backwards of the front wheels of the third cart.

The invention, its use and its advantages will be better understood upon reading of the following non-restrictive description of preferred embodiments thereof, made with reference to the accompanying drawings, in which like numbers refer to like elements.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a side elevation view of pushback storage system for pallets according to a preferred embodiment of the present invention.

Figure 2 is a front elevation view of the four level single column of shelf lanes shown in Figure 1. Figure 3 is a top plan view of a single shelf lane shown in Figure 1 with a series of carts and rails at the front end thereof.

Figure 4 is a top plan view of the shelf shown in Figure 3 with the series of carts extended to the back.

Figure 5 is a top plan view of the carts shown in Figures 3 and 4 separated for better illustration.

Figure 6 is an partial detailed view of the carts and rail shown in Figure 3 inside circle A.

Figure 7 is a cross-sectional view of the carts and rail show in Figure 3 taken along line B-B'.

Figure 8 is a cross-section view of an alternative design for additional carts and rails, according to a preferred embodiment of the present invention.

Figure 9 is a cross-sectional view of another alternative design of carts and rails, according to a preferred embodiment of the present invention.

Figure 10 is a partial detailed view of the carts and rail shown in Figure 9 inside circle C.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figure 1 , there is shown a typical set of racks 3 with vertical uprights 4 and structural braces 5 which support a set of four shelves 6. Each shelf 6 is designed to hold up to five cartons or containers 7 supported on pallets δ.These cartons 7 are placed on the shelves 6 by means of a transfer vehicle, such as the fork lift truck 9 illustrated in Figure 1 , which is located in, and travels along corridors between various sets of racks of the type illustrated in Figure 1.

In this sort of system a single pallet 8 containing a carton 7 is placed at the front of a lane as illustrated at the second shelf from the bottom. When a second pallet is placed on the bottom shelf, the loading vehicle simply pushes the first pallet backwards, as illustrated in Figure 1 , and deposits the second pallet at the front.

In the illustrated system a total of five pallets 8 may be installed as shown at the third shelf 6 from the bottom. The first four pallets are pushed successively rearward on the shelf 6 (by means of carts which will be described later) by each subsequent pallet 8, and the last pallet 8 is placed directly on the shelf 6 itself at the front.

Referring to Figure 2, there is shown a front view of the four shelves 6 that are shown in Figure 1 , with each shelf providing a lane into which five cartons or containers 7 on pallets 8 may be placed. It will be realized that that the single set of five shelves illustrated in Figure 2 would typically be repeated on either side for an indefinite distance so as to provide a bank of shelves, four high, and spaced side by side along a corridor from which the fork lift truck 9 can access the shelves 6.

Each shelf 6 is inclined upwardly to the back so that the pallets 8 must to be pushed uphill, against gravity, to the back when they are installed and will roll towards the front by gravity when the foremost pallets 8 are removed.

Each shelf 6 carries a pair of inclined rails 20 on which travel the wheels of a series of carts illustrated in Figures 3, 4 and 5. In Figure 3, the carts 14, 15, 16, 17 are shown nested together at the front of the shelf to the left of the drawing. In Figure 4 the carts 14, 15, 16, 17 are shown extended as they would be spaced in a shelf which is fully loaded, as illustrated at the top in Figure 1.

In Figure 5 the top cart 14, top middle cart 15, bottom middle cart 16, and bottom cart 17 are illustrated separately. The structure of these carts includes a frame of generally rectangular proportions with four legs each having a wheel, as can be seen from the illustrations in Figure 5 and the cross- sectional drawing of Figure 7. The top cart 14 has a rigid frame made of front and back transversal beams 42, 43, which may be rectangular tubes, and side beams 25, which may be orthogonal corner flanges as best shown in Figure 7. Alternatively, the side beams 25 may also be rectangular tubes. The top cart 14 is provided with four legs 35, which may also take the form of rectangular tubes. The legs 35 are positioned near the corners of the cart 14 at the front and back of the side beams 25. Each leg 35 is provided with a wheel 24 as shown in Figure 7. The four wheels 24 have flanges on the inboard sides thereof and are adapted to run along the top of the rail 20 at the outboard edge thereof as illustrated in Figures 4 and 7.

The top middle cart 15 has a rigid frame made of front and back transversal beams 40, 41 , which may be rectangular tubes, and side beams 26, which may be orthogonal corner flanges as best shown in Figure 7. Alternatively, the side beams 26 may also be rectangular tubes. The top middle cart 15 is provided with four legs 34, which may also take the form of rectangular tubes. The legs 34 are positioned near the corners of the cart 15 at the front and back of the side beams 26. Each leg 34 is provided with a wheel (not shown). The four wheels of the top middle cart 15 have flanges on the inboard sides thereof and are adapted to run along the top of the rail 20 at the outboard edge thereof as illustrated in Figures 4 and 7.

The bottom middle cart 16 has a rigid frame made of front and back transversal beams 38, 39, which may be rectangular tubes, and side beams 27, which may be orthogonal corner flanges as best shown in Figure 7. Alternatively, the side beams 26 may also be rectangular tubes. The bottom middle cart 15 is provided with four legs 33, which may also take the form of rectangular tubes. The legs 33 are positioned near the corners of the cart 16 at the front and back of the side beams 27. Each leg 33 is provided with a wheel 24' as shown in Figure 7. The four wheels 24' have flanges on the inboard sides thereof and are adapted to run along the top of the rail 20 at the inboard edge thereof as illustrated in Figures 4 and 7. The bottom cart 17 has a rigid frame made of front and back transversal beams 18, 37, which may be rectangular tubes, and side beams 28, which may be orthogonal corner flanges as best shown in Figure 7. Alternatively, the side beams 26 may also be rectangular tubes. The bottom cart 17 is provided with four legs 21 , which may also take the form of rectangular tubes. The legs 21 are positioned near the corners of the cart 17 at the front and back of the side beams 28. Each leg 21 is provided with a wheel (not shown). The four wheels of the bottom cart 17 have flanges on the inboard sides thereof and are adapted to run along the top of the rail 20 at the inboard edge thereof as illustrated in Figures 4 and 7.

In order to allow the circulation of the carts 14, 15, 16, 17 on the same side of the rail 20, the front and back legs of each of the carts overlap one behind the other, as best shown in Figure 4.

Referring to Figure 7, a plate 30 is positioned between leg 21 and side beam 28 so that carts 16, 17 may roll one with respect to the other without coming into collision. A plate 29 is also positioned between leg 33 and side beam 27 so that carts 16, 17 may roll one with respect to the other without coming into collision. Similarly, a plate 30' is positioned between leg 34 and side beam 26 so that carts 14, 15 may roll one with respect to the other without coming into collision. A plate 29' is also positioned between leg 35 and side beam 25 so that carts 14, 15 may roll one with respect to the other without coming into collision.

The leg 33 of cart 16 is longer than leg 21 of cart 17 so that the side beam 27 of cart 16 is above the side beam 28 of cart 17. This allows cart 16 to roll on the rail 20 without touching cart 17. The same principle applies for the other carts.

As best shown in Figure 7, the rail 20 may be made of two orthogonal corner flanges that have enough horizontal dimension to allow the carts 14, 15, 16,

17 to roll on the inboard and outboard sides thereof at the same time and without interfering with each other. Figure 7 also illustrates the relatively low profile of the four carts. Figure 6 illustrates the relative position of frames of the carts in the nested position.

So as to avoid that the carts 14, 15, 16, 17 from being accidentally lifted off the rail 20, it is preferable to provide a plate 23 fixed onto each leg of each cart. This plate 23 cooperates with plate 22 that is fixed on a middle portion of the rail 20 to prevent the carts from being lifted off the rails 20.

Because the legs of each cart overlap with the adjacent carts, the carts are thereby linked together. This linkage prevents that cart 14 becomes stuck at the back end of the rail 20 when the other three carts are unloaded in the front part of the rail 20. If not, there could be a risk that cart 14 could suddenly become unstuck and fall unexpectedly towards the front of the rail 20, which could cause an accident.

Referring back to Figure 2, a plate 36 that is positioned on the bottom cart 17 ads another safety feature as this forces the loader operator to clear the cart 17 before placing a pallet 8 in the shelf 6. The absence of this plate 36 at the front end also serves to indicate when a lane is full. In addition, the plate 36 serves as a stop to prevent a pallet being pulled off when the loader is backed away, or otherwise shifting beyond the front edge of the shelf.

Figure 8 illustrates a cross-section of an alternative design which might be used if a shelf was intended to carry more than five pallets deep. An additional rail 32 is used for supporting at least another cart 31. The same principle as described above can be used as those skilled in the art will understand and up to nine pallets may be stored using a pair of additional rails.

Figures 9 and 10 illustrate a cross-section of yet another alternative design according to a preferred embodiment of the present invention. This design is similar as the one shown in Figure 7. The main difference is that the rail 20' is made of single piece having the form of an l-shaped beam. The carts 14', 15,' 16', 17' are mounted to this rail 20' by means of wheels in a very similar manner as described above. It is to be noted that the carts may provided with screened platforms made of metal, wood or other without making major modifications to the system. Also, the manufacture of the carts may be made by clamp joining the transversal beans onto the side beams without requiring soldering as is required in most know carts presently in the market.

In operation, when it is desired to put a second pallet 8 on the shelf 6, the operator of the fork lift truck 9 uses the second pallet 8 to push the first pallet 8, and the first cart 14 on which it rests, rearwardly as illustrated in Figure 1 , until the second pallet securely rests on the top middle cart 15. Subsequently, the other pallets are pushed in the same manner on carts 16, 17. Lastly, the fifth pallet is used to push all four carts rearwardly and the fifth pallet is deposited on the shelf or the rails 20 without any cart beneath it.

When it is desirable to retrieve the stored pallets from the system, the opposite sequences are followed. The foremost pallet is withdrawn and the remaining rearward pallets roll forward by gravity on their respective carts to the frontmost position on the shelf ready for subsequent removal.

Thus, by means of the design of the present invention, a more efficient use of warehouse space may be achieved by enabling the storage of containers or cartons on pallets in racks which are five, six, seven or eight levels high and two, three, four, five, six, seven, eight, nine pallet spaces deep.

Furthermore, by virtue of the design of the carts in the present invention, the frames of the respective carts may nest within each other so that the overall head room occupied by the carts is much less than the cumulative height of carts would be if the entire frame of each cart had to pass over or under the next adjacent cart. The carts according to the present invention are designed so that most load pressures are directed toward transversal beams instead of the side beams.

Dimensions for the shelving, rails, and carts are a matter of design choice but will generally be dictated by industry standards for the size of pallets or containers. Furthermore, because of the design of the present invention, more than three carts may be made to ride on a single pair of rails. There is no other system that can presently do this in the market.

Therefore, a storage system in accordance with the present invention has many of the advantages that wharehouse operators look for: easy to use, reliable and economical to construct, and compact enough to provide significant savings in the volume available for storage space.

Although preferred embodiments of the present invention have been described in detail herein and illustrated in the accompanying drawings, it is to be understood that the invention is not limited to these precise embodiments and that various changes and modifications may be effected therein without departing from the scope or spirit of the present invention.

Claims

CLAIMS: 1. A compact pushback storage system for storing pallets (8) in rows of shelves (6) defining lanes, the system comprising: a first pair of rails (20) running from front to back in each lane, each rail having inboard and outboard side edges for receiving wheels to roll upon the edges, the rails being inclined upwardly from front to rear in said lanes; a first cart (14) having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the outboard side edge of each rail; a second cart (15) adapted to move along the lane and extending below relative to the first cart, the second cart having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the outboard side edge of each rail, the back wheels of the second cart being positioned backwards of the front wheels of the first cart; a third cart (16) adapted to move along the lane and extending below relative to the first and second carts, the third cart having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the inboard side edge of each rail, the back wheels of the third cart being positioned backwards of the front wheels of the second cart; and a fourth cart (17) adapted to move along the lane and extending below relative to the first, second and third carts, the fourth cart having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the inboard side edge of each rail, the back wheels of the fourth cart being positioned backwards of the front wheels of the third cart.

2. The system according to claim 1 , further comprising: a second pair of rails parallel and adjacent to the first pair of rails; a fifth cart cart (31) adapted to move along the lane and extending above relative to the first, second, third and fourth carts, the fifth cart having a rectangular shaped frame and a set of front and back wheels on each side mounted to the frame and adapted to roll on the inboard side edge of each of said second pair of rails.

3. The system according to claim 1 , comprising means to prevent the carts from being lifted off the rails, said means including a plate (22) extending above and centrally with respect of the inboard and outboard side edges of the rails, and a second plate (23) mounted to the carts, a portion of which extends horizontally beneath the first plate.

4. The system according to claim 1 , comprising a plate (36) upstanding from the a front end of the cart nearest the front end of the shelf.

5. The system according to claim 1 , wherein each of the carts include front and back transversal beams having tubular shapes and two side beams each having orthogonal corner flanges.

6. The system according to claim 1 , wherein each of the carts include front and back transversal beams having tubular shapes and two side beams each having tubular shapes.