GB2187433A

GB2187433A - Pallet handling apparatus

Info

Publication number: GB2187433A
Application number: GB08704148A
Authority: GB
Inventors: Peter John Lawlor
Original assignee: MANNS MECHANICAL EQUIPMENT Ltd
Current assignee: MANNS MECHANICAL EQUIPMENT Ltd
Priority date: 1986-02-21
Filing date: 1987-02-23
Publication date: 1987-09-09
Also published as: GB8704148D0

Abstract

A pallet handling apparatus for exchanging pallets beneath a load comprises a lined pallet support structure (3) and a load steadying device (6) movable relative to said pallet support structure for steadying a load supported by said pallet support structure, said pallet support structure being pivotable to a position in which a said pallet is inverted so that said load is temporarily supported by said load-steadying device. The pallet support structure can then be pivoted away from the load-steadying device, whereby pallet substitution may be effected, and thereafter returned, and said pallet support structure and said load-steadying device then pivoted to their original positions for subsequent removal of a load-bearing pallet from said pallet support structure. A pallet abutment member may be positioned by a ram to identify the rearward location of the pallet on the support structure. <IMAGE>

Description

SPECIFICATION Pallet handling apparatus This invention relates to a pallet handling apparatus.

Pallets are now widely used to support a variety of productsfortransportation and/or handling by means of a forktruck or hand pallet truck. Thecostof pallet replacement is reaching unacceptable levels and companies are increasingly concerned to retain their own pallets.

Situations in which pal lets are generally lost occur when goods are despatched on pallets which are expected to be returned but are not in fact returned.

Moreover, some pallets which are returned in place ofthose sent out do not conform to the original pallet specification. Companies are not prepared to suffer this loss norto carry the cost of setting up a pallet recovery system. Pallet pools, whereby a company can send goods outon aspecificpalletwhichbe- longstoa pallet operating organisation andthatorganisation is directly responsibleforthe recovery and maintenance of its pool pallets, are in operation, but the problem still exists that manufacturers use their own 'in-house' pallets for specific production tasks and wish to transfer loads from their in-house pal lets to the pool ortransport pallets.

Equipment already exists to transfer loads from an in-house pallet to a pool pallet. This equipmentgenerally incorporates rotation and clamp systems to in verttheload priorto palletchange. The known system has four disadvantages.

1. The pallet position in the exchange mode is nearlyalwayswell above ground level and there is some risk of load damage when the pallet is removed and replaced with another.

2. A vehicle with a power source is normally nee ded to achieve lift to enable pallet exchange.

3. If a manual system is used, it is likelythatthe pallet weight could exceed the proposed manual lift weight limit of 35 kg, currently envisaged by Parliament.

4. Because of the position ofthe pallet in relation to the ground, a hand pallettruck (a common method of moving pallet and load) cannot be used, because a hand pallet truck has minimal lift capability.

According to a first aspect of the present invention there is provided a pallet handling apparatus which apparatus comprises a frame, a palletsupportstructureforsupporting a load-bearing pallet,and a load steadying device movable relative to said palletsupport structure for steadying a load supported by said pallet support structure, said pallet support structure and said load-steadying device being pivotable relative to said frame from a first position in which a loadbearing pallet can be received by said pallet support structure, to a second position in which a said loadbearing pallet is inverted so that said load istem porarily supported by said load-steadying device and so that a said load no longer bears upon a said pallet, said pallet support structure being thereafter pivotable away from the said load-steadying device whereby pallet substitution may be effected, and said pallet support structure and said load-steadying device being pivotable from said second position to said first position for subsequent removal of a loadbearing pallet from said pallet support structure.

Preferably said frame has a plan in the form of a letter 'H', with an upright extending from each end of the cross-bar of the frame, for pivotal support ofthe palletsupportstructure.

The pallet support structure generally includes a pair of forks or tines for insertion into appropriate sockets provided in the pallet.

Preferably the load-steadying device includes an upstanding back plate which facilitates support of the load when the load is in an inverted position, and a plate-like structure for steadying and supporting a said load in an inverted position.

The plate-like structure is preferably mounted on a said upstanding back plate and arranged to be movable towards and away from a said pair of tines ofthe pallet support structure. The load-steadying device may also include one or more side walls or aristo further steady the load.

The apparatus of the present invention may be operated by any suitable means; it is preferred how everthat the apparatus be operated pneumatically or hydraulically, for which purpose a suitable source of pressurized fluid is required, together with piston and cylinder devices as appropriate.

In orderto preventthe possibility of load damage, it is clearly desirable that a load carried by a said load-bearing pallet be so arranged on the pallet handling apparatus that the load abuts the upstanding back plate. However, in practice it cannot be guaranteed thatthe load face will bein line with the rear edge ofthe load pallet. The pallet may be inboard ofthe load or may project beyond the load and thus locating a said pallet upon the tines ofthe pallet support structure may not cause the load to abut the upstanding back plate. Alternatively ifthe load does abut the back plate the pallet itself may not be fully received onto the tines of the palletsupportstruc- ture.

In practice, therefore, it is clearly desirable that the load of a said load-bearing pallet should abut a said upstanding back plate thus to ensure that there is no relative movementtherebetween during inversion of the load, and to avoid any damage to the load.

Moreover, it may be a policy to load a pallet with the load inboard thereof, or level with an edge thereof, or even extending beyond an edge thereof.

There may thus be a need to ensure that any pallet substituted forthe original is so presented to the load as to be in the same relative position as the original pallet.

In simpler embodiments of the present invention it may not always be possible to ensure that thesetwo desiderata are met, since, for example, the load may not be positioned on the pallet so as to permitabutment of load and back plate. Moreover, the depth of the main frame may allow a projecting pallet to travel under it.

According to a further aspect of the present invention there is provided a pallet handling device ofthe type defined above which additionally includes a pallet abutment member provided on said pallet support structure, said pallet abutment member being adapted to be moved in translation by a said pallet as a said pallet is received by said pallet support struc- ture and which pallet abutment member is lockable in a position to which, in use, it is moved by a said pallet.

Preferably locking means for the pallet abutment member comprise a power source arranged to be operated pneumatically or hydraulically. Preferably the power source is provided with a neutral mode such that a pallet presented to the abutment member will push against said member and move said member backwards. Movement backwards ofsaid memberwill continue underthe urging of a said pallet until the load borne by such a pallet abuts the load-steadying device. The abutment member is then locked in position, thereby to define the position of a said pallet. Upon substitution of pallets using the pallet-handling apparatus, the replacement pallet will be located by said abutment member and by said pallet support structure in generally the same position relative to a load as the original pallet.

The pallet abutment memberwill pivot with the pallet support structure (e.g. with a pair of tines).

Embodiments of pallet handling apparatus according to the present invention will now be described, byway of example only, by reference to the accompanying drawings in which: Figure I represents diagrammatically features of a first embodiment ofthe present invention and a method for its use; and Figure 2 shows in extremely diagrammatic form an embodiment of an arrangement of the pallet sup port structure and pallet abutment member of the present invention.

Referring to Figure 1 ofthe drawings, a frame, generally H-shaped in plan (not shown) is provided with an upright at each end ofthe crossbar ofthe 'H', one of which uprights is shown designated 1. Pivotally mounted between the uprights lisa pallet support structure 2, comprising a pair of horizontally extending tines (one of which is shown at 3). A loadsteadying device 4 is provided comprising an upstanding back plate 5 and a load-steadying plate 6 mounted in a plane generally parallel to a plane in whichthetines3 lie. Thetines 3 are capableof pivotal movement independently of said back plate 5. The load-steadying plate 6 is arranged to be movable upon said back plate 5, towards and awayfrom the tines 3.

Hydraulic means are provided for moving the plate 6to and from the positions shown respectively in sketches A and B whilstfurther hydraulic means are provided for pivoting the pallet support structure to and from the positions shown respectively in sketches A and C.

The apparatus shown in Figure 1 ofthe drawings is employed as follows.

Aforktruck or hand pallet truck (not shown) carry- ing a loaded pallet approaches the pallet handling apparatus in the direction of the arrow in sketch A and locates the load-bearirlg pallet on tines 3 ofthe pallet handling apparatus. (The tines are spaced at centres such that both the tines ofthe forktruckor hand pallet truck and the tines ofthe apparatus can be accommodated within the sockets ofthe pallet.) The load ofthe load-bearing pallet is located so that it bears against back plate 5. The forktruck or hand pallet truck is then withdrawn, leaving the load bearing pallet in position on the pallet handling apparatus (sketch A).

The load-steadying plate 6 is then moved down wardly to bear against the upper surface of the load (sketch B).

As shown in sketch C, the assembly oftines 3, back plate 5 and load-steadying plate 6 is pivoted, main taining the same orientation relative to each other, in a clockwise direction to invert the load and pallet.

Once the load has been inverted and is supported by back plate 5 and load-steadying plate 6 (sketch D), tines 3 are pivoted anti-clockwiseto facilitate re moval ofthe original 'in-house' pallet and its replace ment by a transport pallet.

After pallet substitution has taken place, the pallet support structure 2 and the pallet which it carries are rotated clockwise to bear against the still-inverted load (sketch E), and thereafterthe assembly of pallet support structure, pallet, load and load-steadying device is rotated anti-clockwise to resume its original position (sketch F),whereafterthe load-steadying plate 6 is moved in the direction of the vertical arrow to allowthe pallet and load to be removed from the pallet handling apparatus.

Referring nowto Figure2,thereisshowndia- grammatically part of a pallet support structure. A back plate 5 is provided, performing precisely the same function as in the embodiment of Figure 1. In addition however, there is provided a pallet abutment member7 in the form of a bar8 mounted on a pivot9for rotational movementthereabout.The pivot 9 is so positioned as to cause the bar 8 to hang underthe influence of gravity in a 'forward' position, i.e. a position in which it is located forward ofthe plane of the back plate 5. It is of course possible to provide springs orthe liketo bias the bar8 into said forward position.

A hydraulic piston and cylinder device 10 is arranged to co-act with an extension arm 11 adapted to rotate about pivot 9 with the bar 8. The hydraulic arrangement is such that the bar 8 can be either permitted to move (effectively moving in translation, leftwards orrightwards in Figure 2) orcan bylocking the piston and cylinder 10 be held in any given position.

It is to be noted that the items 7 to 11 are notassociated with the back plate 5 upon performing inversion of pallet load and substitution of pallet, but rather are arranged to move with the frame and with the pallet support structure 2.

The bar 8 is so located that in its forward or rest position it extends into the region to be occupied by a pallet, so that as a loaded pallet is located on the apparatus ofthis invention the bar 8 of the pallet abutment member is moved backwardly by the pallet until the pallet reaches a final position (thatfinal position being determined normally either bythe pallet abutting the back plate 5 or by the load supported by the pallet abutting said back plate 5). Thereafterthe bar8 may be 'locked' in the position to which it has been moved by the inserted pallet, by actuating the hydraulic piston and cylinder device 10.The re sult is that when the steps of inversion, pallet re moval and pallet substitution occur,the replacement pallet can only be inserted onto or located relative to the pallet support structure 2 to that extent enjoyed by the original pallet.

In the embodiments so far described it has been assumed that the pallets employed possess bottom stringers so that movement of the pallet support structure from the inverted position will cause the inverted palletto leave the inverted load. Clearlythis however will not occur if no bottom stringers are present on the pallets. To overcome this, a pair of laterally movable clamping members may be provided, associated with the pallet support structure. The said laterally movable clamping memberswill normally move in 'sideways' of the pallet to grip its sides and will move with the pallet support structure both to and from the inverted position.

Additionally, for those cases where the load is movable, e.g. in the form of bags of produce or boxes or cartoons not banded together, it is contemplated that one or more sideways load-steadying walls may be provided. Such load-steadying walls may be arranged to be laterally movable e.g. in syn ch ronisation with movement of the load-steadying piate 6.

The pallet handling apparatus ofthe present invention may include other modifications or refinements. For example; not all pallet loads are square in plan. It is preferred that the top steady plate 6 be oblong rather than square and that it be pivotable about a pivot (a pivot which is vertical with referenceto Figure 1 A) so as to conform more closely to the plan ofthe load borne by the pallet.

A photo-electric beam may extend between the forks or tines of the pallet support structure 2, as a safety feature, so that operation ofthe apparatus is prevented if the beam is interrupted, e.g. by the legs of an operative standing between the tines.

As the top steady plate is advanced towards the load, a stop switch is activated when the top steady plate abuts the load so as to lock the top steady plate in the abutting position. This may be achieved by associating the cylinder of a hydrauliccylinderand piston device for moving the top steady plate with a said stop switch, the arrangement being such that during normal advance of the top steady plate the cylinder will not move relative to the stop switch but when the plate abuts the load, reaction will cause the cylinder to move away from the load thus activating the stop switch to 'lock' the top steady plate. Preferably, the distance by which the top steady plate is advanced is sensed and is then used to control rotational movement of the pallet support member.In particular, by sensing the said distance, the spacing be tweenthetopsteady plateandthe pallet support member may be determined and rotational movement of the pallet support member back to its inverted position (step E in Figure 1 ) limited accordingly.

The spacing between forks ortines of the pallet support member may be arranged to be adjustable to cope with pallets of various sizes and arrangements.

Preferably a three-phase electric motor is provided to power the hydraulic systems of the apparatus.

When the apparatus ofthe present invention is in its inverted position (Figures 1 D and 1 E), the top steady plate and the back plate are preferably iocked totheframe ofthe apparatus. Such locking is ciearly desirable from a safety viewpoint but may on occasion be necessary where the centre of gravity ofthe load in its inverted position is forward ofthe main pivot of the apparatus. It is however highly desirable that the load should move to an 'over-centre' position when in its inverted position. Preferablythevarious interlocks and cycles ofthe apparatus of this invention are controlled automatically, e.g. by CNC devices or by means of microprocessor.

The present apparatus provides a reliable, efficient and cost-effective means for dealing with pallets to ensure that in-house or other pallets may be retained and to facilitate pallet substitution.

Claims

1. A pallet handling apparatus, which apparatus comprises a frame, a pallet support structure for such porting a load-bearing pallet, and a load steadying device movable relative to said pallet support struc tureforsteadying a load supported by said pallet support structure, said pallet support structure and said load-steadying device being pivotable relative to said frame from a first position in which a loadbearing pallet can be received by said pallet support structure,to a second position in which a said loadbearing pallet is inverted so that said load istemporarily supported by said load-steadying device and so that a said load no longer bears upon a said pallet, said pallet support structure being thereafter pivotable away from the said load-steadying device whereby pallet substitution may be effected, and said pallet support structure and said load-steadying device being pivotable from said second position to said first position for subsequent removal of a loadbearing pallet from said pallet support structure.

2. Apparatus according to Claim 1,whichinclu- des an upstanding back plateforfacilitating support of the load when the load is in an inverted position, and a plate-like structure for steadying and support- ing a said load in an inverted position.

3. Apparatus according to Claim 2, wherein the plate-like structure is mounted on a said upstanding back plate and arranged to be movable towards and awayfromthe palletsupportstructure.

4. Apparatus according to Claim 3, wherein said plate-like structure is in the form of an oblong plate which is pivotable about an axis which is substantially at right angles to the plane of said plate.

5. Apparatus according to any one of the preceding Claims, and arranged to be powered hydraulicaily.

6. Apparatus according to any one ofthe preceding Claims, which includes a pallet abutment member provided on said pallet support structure, said pallet abutment member being adapted to be moved in translation by a said pallet as a said pallet is received by said palletsupportstructure and locking meansforlockingsaid pallet abutment member in a position to which, in use, it is moved by a said pallet.

7. Apparatus according to Claim 6, wherein said pallet abutment member is arranged to be suspen ded from and to be rotatable about a pivot.

8. Apparatus according to Claim 6, wherein said pallet abutment member is resiliently biased into a position in which it will abut a pallet member as a said pallet member is received by said pallet support structure.

9. Apparatus according to any of Claims 6 to 9, wherein said locking means include a hydraulic piston and cylinder device.

10. Apparatus according to any one of the preceding Claims, which further includes one or more laterally movable clamping members, associated with the pallet support structure, for clamping a said palletwhilstitis moved to and from a said inverted position.

11. Apparatus according to any one ofthe preceding Claims, which further includes one or more load steadying walls, arranged to be movable late rally,forsteadying and supporting a said load.

12. Apparatus according to anyone of the preceding Claims, wherein the pallet support structure comprises a pair of tines or forks, adjustment means being provided to adjustthe lateral spacing between said tines or forks.

13. Apparatus according to anyone ofthe preceding Claims, wherein means are provided for locking said load-steadying device in said inverted position.

14. A pallet handling apparatus, substantially as herein before described with reference to Figure 1 of the accompanying drawings, or as modified by reference to Figure 2 of the accompanying drawings.

15. Thefeatures hereinbefore disclosed, ortheir equivalents, in any novel selection.