WO1997039968A1

WO1997039968A1 - Pallet stacker

Info

Publication number: WO1997039968A1
Application number: PCT/SE1997/000650
Authority: WO
Inventors: Kenth WETTERSTÉN
Original assignee: Wettersten Kenth
Priority date: 1996-04-22
Filing date: 1997-04-17
Publication date: 1997-10-30
Also published as: SE9601526L; SE510217C2; SE9601526D0

Abstract

Pallet stacker for upstacking or downstacking of pallets, resting on each other in a stack. The pallet stacker comprises a lift mechanism, being disposed to lift a lower pallet one or more pallet heights, at wish, in engagement at two opposite side edges of said pallet for enabling upstacking of pallets during building-up of the stack from beneath. The lift mechanism is in one embodiment disposed to engage two opposite side edges of the second lowest pallet of the stack for lifting this pallet and the pallets above, at least one pallet height for enabling the removal of the lowest pallet of the stack and thus, downstacking from beneath.

Description

Pallet stacker

The present invention relates to a pallet stacker, i. e. a stacker for the upstacking or downstacking of pallets resting on each other in a stack, preferably standard size pallets, such as so called EUR-pallets or European pool pallets. At the present time, pallets often will be handled by means of rather heavy and expensive fork trucks, e.g. in workshops, storages and the like. Alternatively, they will be handled all by hand, i.e. they will be lifted and moved by hand, which is a heavy, time consuming and risky occupation, as well, in view of the risks of personal injuries, damages of goods and products and ofthe pallets themselves. Often, due to the heavy and troublesome handling, people neglect to stack the empty pallets in proper stacks at proper locations, the pallets being separately left at ill-placed locations, and thus occupying unnecessary space on the floor.

The object ofthe present invention is to provide a pallet stacker, which eliminates the above shortcomings and which further makes it possible to keep control ofthe pallets and to save truck time and to reduce pallet wear, the pallets easily being transportable to desired locations by means of simple and cheap pallet carriages, when needed.

Another object ofthe present invention is to provide a pallet stacker, which comprises a minimum of movable parts, having a simple and robust construction, the driving of which being reliable and powerful, as well, so that the pallet stacker may be used outdoors, as well, even in very cold weather.

For these mentioned objects, the pallet stacker ofthe present invention is substantially characterized in that the pallet stacker comprises a lift mechanism, being disposed to lift a lower pallet in engagement with this lower pallet at two opposite side edges thereof, one or more pallet heights, at wish, for enabling the upstacking of pallets when building-up the stack from beneath.

Preferably, according to the invention, the lift mechanism is disposed to engage two opposite side edges ofthe second lowest pallet ofthe stack for lifting this pallet and the pallets above this pallet to at least one pallet height for enabling removal ofthe lowest pallet ofthe stack and thus, downstacking from beneath. Hereinafter, the invention will be explained more in detail with reference to the annexed drawings.

Fig. 1 is a view in perspective, showing an as an example chosen embodiment of a pallet stacker ofthe invention, used for the upstacking of pallets; Fig. 2 is a view in perspective of another as an example chosen embodiment of a pallet stacker ofthe invention, which is used for the downstacking of pallets, the pallets being released one by one from a stack;

Fig. 3 is a side view ofthe pallet stacker ofthe present invention, partly in section; Figs. 4, 5 and 6 shows details ofthe body ofthe pallet stacker ofthe present invention in a side elevational view, a rear elevational view, and a top elevational view, respectively;

Fig. 7 depicts that space on the pallet stacker ofthe present invention where the operating and lift mechanism is disposed, with some parts broken away, so that the mechanism may be seen;

Fig. 8 discloses the operating and lift mechanism of Fig. 7 alone, at a slightly enlarged scale;

Fig. 9 is a side view of a left lift beam;

Fig. 10 is an end view ofthis lift beam; Fig. 11 is a sectional view at an enlarged scale along the line C-C in Fig. 9;

Fig. 12 depicts the encircled detail A of Fig. 9 at a larger scale;

Fig. 13 depicts the encircled detail B of Fig. 9 at a larger scale;

Figs. 14 and 15 are views corresponding to those of Fig. 9 and Fig. 10, but showing the right lift beam. The pallet stacker ofthe invention, shown as an exemplary embodiment in Figs. 1 and 2, is intended for a European pool pallet with the dimensions 800 x 1200 mm and can normally be loaded with 20 pallets at most. Of course, other dimensions and other numbers could be imagined. In the example of Fig. 1 a pallet stacker is shown, generally referenced by 10, which is used for the upstacking of pallets L in a stack S, the purpose of Fig. 1 being to demonstrate that pallets L could be stacked one by one, two at a time or three at a time, the pallets being transported to the pallet stacker resting on a so called pallet carriage, not shown, for building-up ofthe pallet stack from beneath.

As shown in Fig. 2 the pallet stacker 10 is used for the downstacking of pallets one by one from the stack S, the pallets being removed from the lower end ofthe stack by means of a pallet carriage. Though not shown, it will also be possible to completely empty the pallet stacker 10 by removing the whole pallet stack S at a time.

The pallet stacker 10 shown, comprises a box body 11 , which in a top elevational view has the shape of an U, and which is open in one end (the left end in Fig. 3) for enabling the insertion and removal ofthe pallets. In a particular embodiment the box body has a lower opening in its rear side, opposite the open end, for enabling the transfer ofthe pallets through the stacker. The legs 11 A, 1 IB and the cross beam or rear member 11C ofthe U-shape are shaped as boxes for receiving the operating and lift mechanism, Figs. 4, 5 and 6.

The lift mechanism ofthe pallet stacker comprises a hydraulic cylinder 12, which is supplied from a hydraulic unit 14, via a hydraulic hose 13. A comparison between Figs. 7 and 8 shows that the hydraulic cylinder 12 is disposed to raise or lower, respectively, a yoke 15, on which two sprockets 16, 17 are rotatably mounted side by side. The sprockets 16, 17 serve as guide rolls for respective chains 18, 19, the inner ends of which being attached to respective attachments 20 and 21, respectively, provided on a mobile carrier, generally referenced by 22, the outer ends ofthe chains being attached to respective pivotable lift beams 23 and 24, respectively. The lift beams 23, 24 are pivotable around axis 25, 26 and their upper ends are biased to be pivoted in a direction towards each other by means of a spring 27 extending therebetween, so that cam rolls 28 at the lower ends ofthe lift beams can run either on the outside of a respective cam 29 or on the inside ofthe cam 29 in question.

The apparatus is constructed in such a way, that the lower ends ofthe lift beams 23, 24 are pivoted in a direction towards each other against the action ofthe spring 27, when the hydraulic cylinder 12 displaces its piston rod upwardly to the position shown in Fig. 8. The lower ends ofthe lift beams will then be pivoted towards each other, till they will abut a respective bolt 30, Fig. 7 and Fig. 8, whereupon their pivot movement will be stopped, the lift beams being substantially vertical. Then tiltable lift tongues 31 provided on the lift beams will occupy a horizontal position, in which they can engage a pallet for lifting the same (together with any overlying pallets ofthe stack), when the mobile carrier 22 moves upwardly. This upwards movement of the carrier 22 occurs upon the continued prolongation ofthe hydraulic cylinder, so that the yoke 15 will move upwardly.

The question, whether the cam rolls 28 will run on one side ofthe cams 29, thereby keeping the lift tongues 31 in an operative, lift position during the total movement upwardly ofthe lift beam (for the insertion of one, two or three pallets from beneath in case of upstacking), or initially keep them retracted in a non lifting position during a longer or shorter distance ofthe movement ofthe lift beam for, so to speak "omitting" the lowest pallet (during downstacking), will be determined by the angular position of the shaft 32, which is operable by a lever 32A and which is provided with a protruding finger 33, which may lift a tillable abutment finger 34.

Of course, the pallet stacker ofthe invention is provided with necessary control means for the control ofthe operations of e.g. the hydraulic cylinder 12 and for the control ofthe separate operations, for example in such a way that the lifting or lowering movement will be stopped and can not be started if a pallet has got stuck or has been inserted askew in the stacker etc.

Various modifications and variations of details could be made within the scope of the invention described above and defined in the claims.

Claims

1. Pallet stacker for upstacking or downstacking of pallets resting on each other in a stack, characterized in that the pallet stacker comprises a lift mechanism, which is disposed to lift the lower pallet one or more pallet heights as desired in engagement with two opposite side edges of said pallet for enabling upstacking of pallets, when building- up the stack from beneath (Fig. 1).

2. Pallet stacker in accordance with claim 1, characterized in that the lift mechanism is disposed to engage two opposite side edges ofthe second lowest pallet of the stack for lifting said pallet and those pallets, which are situated above said pallet, at least one pallet height, for enabling the removal ofthe lowest pallet of the stack and thus downstacking from beneath (Fig. 2).

3. Pallet stacker according to claim 1 or claim 2, characterized in that the lift mechanism ofthe stacker comprises a hydraulic cylinder (12), which is supplied by a hydraulic unit (14) and is disposed to raise and lower, respectively, a yoke (15), on which two sprockets (16, 17) are rotatably mounted side by side, said sprockets (16, 17) serving as guide rolls for respective chains (18, 19), having their inner ends attached to respective attachments (20 and 21 , respectively), provided on a mobile carrier (22), the other outer ends of said chains being attached to respective lift beams (23 and 24, respectively), which are disposed for engagement with a desired pallet at each occasion, that is at wish the lowest pallet (when upstacking) or the second lowest pallet (when downstacking).