GB1569880A - Depalletizing apparatus - Google Patents

Description

(54) DEPALLETIZING APPARATUS (71) We, METAL BOX LIMITED, a Company Incorporated under the laws of Great Britain, of Queens House, Forbury Road, Reading RG1 3JH, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: This invention relates to apparatus for depalletizing layers of articles, one layer at a time, from a pile of superimposed layers which have separating elements positioned therebetween and which are carried by a pallet resting on a support therefor and for transferring the layers from the separating elements on to a layerreceiving surface located at a predetermined height from the ground, said apparatus comprising a transfer head reciprocable in a vertical path and including a transfer table to receive layers one at a time from the top of the pile, means operable to lower or raise, as appropriate, the transfer head relative to the pallet support and the layer-receiving surface thereby first to align the transfer table with the top layer of the pile and then to align the transfer table with the layer-receiving surface, transfer means associated with the transfer head and operable to move the top layer from the pile on to the transfer table and then to move the layer from the transfer table on to the layer-receiving surface, and operating means operable to reciprocate the transfer means and thereby move the layers over the transfer table in its lengthwise direction. Such an apparatus will be referred to below and in the appended claims as " apparatus of the kind described ".

It is desirable that while the top layer is being removed from the pile the next lower layer be constrained against movement irrespective of whether or not it is slightly out of vertical alignment with the other layers of the pile and it is an object of the invention to provide means adapted to this purpose.

According to the invention there is provided apparatus of the kind described including pairs of opposed clamp members movable with the transfer head and relative thereto and one to the other, and clamp member actuating means operable, when the transfer means is aligned with the top layer of the pile preparatory to effecting movement of the top layer on to the transfer table, to actuate the clamp members independently to engage the sides of the layer next below the top layer in a manner such that, irrespective of the position of alignment of said next lower layer in relation to the other layers of the pile, said next lower layer is gripped between the clamp members in the position at which it is presented for engagement by the clamp members and is stabilised in that position during movement of the top layer on to the transfer table by the transfer means.

When the separating elements consist of pads there is a tendency for a pad supporting the top layer to be displaced during movement of the layer from the pad on to the transfer table and it is a preferred object of the invention to provide the apparatus with means for restraining the pad while the layer is being removed therefrom.

With this object in mind the apparatus preferably includes gripper means movable with the transfer head and comprising a fixed gripper and a movable gripper, and gripper means actuating means operable when the transfer means is aligned with the top layer of the pile preparatory to effecting movement of the top layer on to the transfer table to actuate the movable gripper to grip and hold between the grip pers a pad supporting the top layer while the top layer is moved by the transfer means from the pad on to the transfer table.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: - Fig. 1 is a diagrammatic side elevation of apparatus according to the invention, Fig. 2 is a diagrammatic top plan of a part of Fig. 1 Fig. 3 is a diagrammatic side elevation of Fig. 1, Fig. 4 is a section on line IV-IV, Fig. 2, through the transfer head of the apparatus, Fig. 5 is a part section on line V-V, Fig.

4, Fig. 6 is a part end elevation, partly in section, Fig. 7 illustrates the index arm and associated parts, Fig. 8 is an end view illustrating the sweep member and index arm, and Fig. 9 illustrates the sequence of operations of the apparatus as controlled by control means embodied in the apparatus.

Referring to the drawings, layers 1 of articles, for example upright bottles, are superimposed and loaded as a pile on a pallet 2. Separating elements, such as pads or inverted trays not shown, are positioned between the layers 1. The layers are to be transferred one at a time, starting at the top of the pile, to a receiving surface 3 which is located at a fixed predetermined height from the ground. The surface 3 may be that of a conveyor.

The depalletizing apparatus comprises a self-supporting and free-standing frame 4 which includes a support 5 for a loaded pallet 2, which may be placed on the support 5 by a forklift truck, and an elongate transfer head 6 which is supported for movement lengthwise of and between vertical frame elements 7 which extends upwards from the support 5. The transfer head 6 is provided with rollers 8 which run on the frame elements 7, and up-and-down movements of the transfer head 6 are effected by an electric chain- or cable-hoist 9, controlled by a control means 10. The hoist is a two-speed hoist and is provided with a brake not shown.

The transfer head 6 includes side members 11 which at one end of the head permit the passage therebetween of the layers 1 of the loaded pallet on the support 5 during movement of the transfer head 6 lengthwise of the frame elements 7 which are hollow. The transfer head carries rollers 8 which run on the facing surfaces of the frame elements 7, Fig. 3. Counterweights 13 are housed in the frame elements 7. The opposite end of the transfer head 6 is provided with a transfer table 14, Fig. 4, which is to receive a layer 1 in preparation for the transfer thereof to the surface 3.

Transfer means, shown as a sweep member 15, is arranged when the transfer table 14 is aligned with the bottom of the top layer to move the top layer on to the transfer table 14. The sweep member is carried by chains 16 driven by a motor 17 and chain 18, Fig. 5, controlled by the control means 10. The motor 17 may also be a two-speed motor provided with a brake not shown. The transfer head 6 is also provided with self-aligning guides 19, Fig. 3, which have the forward ends thereof anchored to the transfer head, as at 20, Fig. 2, only one of the guides being shown.

The layers are guided between the guides 19 while being moved on to the transfer table 14.

The transfer head is provided with pairs of opposed clamp members 21 which are movable with the transfer head and relative thereto and one to the other and clamp member actuating means, shown as pneumatic cylinders 22, are operable when the transfer means, that is the sweep member 15, is aligned with the top layer of the pile, Fig. 4, preparatory to effecting movement of the top layer on to the transfer table 14. The pneumatic cylinders 22 are double-acting and are operated independently one of the other so that as they engage the sides of the layer next below the top layer they individually cease to operate.By this means the opposite sides and opposite ends of the layer next below the top layer are clamped between the clamp members 21 in a manner such that, irrespective of the position of alignment of the said next lower layer in relation to the other layers of the pile the next lower layer is gripped between the clamp members 21 in the position at which it is presented for engagement by the clamp members and is stabilised in that position during movement of the top layer on to the transfer table 14 by the sweep member 15. The front clamp member is provided with a dead-plate 23, Fig. 4, which ensures a smooth transfer of top layer on to the transfer table 14.

When the layers 1 are separated by pads the transfer head 6 is provided with gripper means, consisting of a fixed gripper 24 and a movable gripper 25. The gripper means are movable with the transfer head and gripper means actuating means shown as a pneumatic cylinder 26 is operable when the sweep member 15 is aligned with the top layer of the pile preparatory to effecting movement of the top layer on to the transfer table 14 to actuate the movable gripper 25 to grip and hold between the grippers 24, 25 the pad supporting the top layer while the top layer is moved by the sweep member 15 on to the transfer table 14.

The sweep member 15 is supported by a shaft 27, transverse to and mounted for reciprocation lengthwise of the transfer table 14 by the chains 16. The sweep member is angularly movable with and freely movable axially of the shaft 27, being guided by rollers 28, Fig. 8, which run on a guide rail 29. Preparatory to a sweeping movement, the sweep member 15 is located relative to the top layer and the guide by the engagement of rollers 30 carried by the sweep member with the side guides 19, which extend lengthwise of the transfer table 4.

The control means 10 including electrical or electronic means and a memory for controlling the automatic functions of the apparatus, and height index controls which provide automatic height indexing in two stages, first to stop the transfer head 6 level with the top layer 1 of the pile, and second to stop the transfer head 6 at the correct level for transfer of a layer from the transfer table 14 to the layer-receiving surface 3. For indexing to stop the transfer head level with the top layer there is provided an index arm 32 which is freely rockable about the shaft 27 and which carries a roller 33 to engage the top of the top layer of the pile.An elevator arm 34 is movable with the index arm 32 and carries a cam follower 35 which is engaged with a cam track 36 during movement of the sweep member 15 towards the layerreceiving surface 3 to raise the index arm 32 out of engagement with the layer being moved by the sweep member 15. An operating arm 37 is pivotally mounted on the transfer head and is movable by the elevator arm 34 to actuate a proximity switch 38 to initiate, through the control means 10, operation of the clamp member operating cylinders 22 and motor 17.

For indexing the transfer head to the discharge or transfer level a duplex proximity head detection unit, not shown, is fitted to the transfer head and is actuated by " targets ", not shown, fitted to the conveyor 3. One of such targets serves to provide a levelling signal for discharge or transfer and another provides a signal to the memory circuits, Fig. 9, of the control system in order that the transfer head may travel in the correct direction, either upward or downward, after the transfer of a layer to the layer-receiving surface 3.

To prevent toppling of leading articles of a layer during movement of the layer to the position at which it is positioned on the transfer table 14 for transfer to the layer-receiving surface, 3, the transfer head is provided with two hanging curtains 39, 40, shown diagrammatically in Fig. 4, each of which is slit vertically into a series of "fingers". The curtain 39 is retractable and is pneumatically operable, by means not shown, to be withdrawn when the transfer head is descending round the top layer of the pile so as to provide an adequate clearance for the passage of the transfer head about the top layer.

The sequence of operation of the apparatus, shown in Fig. 9 is as follows: - A loaded pallet is positioned on the support 5 and the transfer head 6 is then lowered under direct operator control and the first height index is made by index arm 32. The apparatus then, through proximity switch 38, goes into automatic cycle with the clamp members 21 being moved inwards to clamp the layer next below the top layer, and the grippers 24, 25, when the layers are separated by pads, gripping the pad on which the top layer rests. The sweep member 15 positions itself axially of shaft 27 and the curtain 39 moves into position.

The sweep member 15 then moves forward from the rest position, full line position, Fig. 7, engages the top layer and moves it on to the transfer table 14. On completion of this movement of the sweep member 15, the clamp members 21 and the grippers 24, 25, if used, move out, and curtain 39 moves back. The transfer head 6 then lowers and stops in the position indicated by broken lines in Figure 1 when the transfer table 14 is aligned with the layer-receiving surface 3.

The automatic operation then ceases and the operator removes the layer from the transfer table 14 on to the surface 3 by controlling movement of the sweep member 15 by a joystock, not shown, provided on the control means 10, first ensuring that sufficient space is available on the surface 3.

The operator removes the inverted tray, if used, or the pad from the top of the transferred layer as the pad, when used, is, after the first layer, carried with each layer as it is removed from the top of the pile.

On completion of the full stroke of the sweep member 15 the automatic cycle is resumed and the transfer head 6 is raised to a position above the pile on the pallet, the sweep member 15 being restored to the rest position only when the transfer head 6 has been moved above the top of the pile.

The cycle just described is repeated until all of the layers have been removed from the pallet afterwhich the transfer head 6 returns to the uppermost position thereof where it remains until the programme is again initiated by the operator.

When the level of the pile has been reduced so that it is below the level of the surface 3 the transfer head 6 is first lowered to pick up the top layer and is then raised to the level of the surface 3 for the transfer of a layer. This facility is provided automatically by the memory circuits of the control means.

WHAT WE CLAIM IS: - 1. Apparatus of the kind described including pairs of opposed clamp members movable with the transfer head and reIative thereto and one to the other, and clamp member actuating means operable, when the transfer means is aligned with the top layers of the pile preparatory to effecting movement of the top layer on to the transfer table, to actuate the clamp members independently to engage the sides of the layer next below the top layer in a manner such that, irrespective of the position of alignment of said next lower layer in relation to the other layers of the pile, said next lower layer is gripped between the clamp members in the position at which it is presented for engagement by the clamp members and is stabilised in that position during movement of the top layer on to the transfer table by the transfer means.

2. Apparatus according to Claim 1 wherein the transfer means comprises a sweep member supported by a shaft transverse to and mounted for reciprocation lengthwise of the transfer table by said operating means, and where in the sweep member is freely movable axially' of the shaft and is locatable relative to the transfer table by the clamping members of the pair thereof arranged to engage the sides of said next below layer which extend lengthwise of the transfer table.

3. Apparatus according to Claim 1 or Claim 2 including gripper means movable with the transfer head and comprising a fixed gripper and a movable gripper, and gripper means actuating means operable when the transfer means is aligned with the top layer of the pile preparatory to effecting movement of the top layer on to the transfer table to actuate the movable gripper to grip and hold between the grippers a pad supporting the top layer while the top layer is moved by the transfer means from the pad on to the transfer table.

4. Apparatus according to any one of Claims 1 to 3 including an index arm movable with the transfer head and pivotally mounted thereon, said arm being arranged to engage the top of the top layer of the pile, an elevator arm movable with the index arm and carrying a cam follower engageable with a cam track during movement of the transfer means towards the layer-receiving surface to raise the index arm out of engagement with the layer being moved by the transfer means, an operating arm pivotally mounted on the transfer head and movable by the elevator arm, to actuate a switch to initiate operation of the clamp member actuating means and said operating means, and a fixed stop engageable by the elevator arm to determine the lowermost position of the index arm.

5. Apparatus according to Claim 2 and Claim 4, wherein the index arm is freely rockable about said shaft.

6. Apparatus of the kind described substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. reduced so that it is below the level of the surface 3 the transfer head 6 is first lowered to pick up the top layer and is then raised to the level of the surface 3 for the transfer of a layer. This facility is provided automatically by the memory circuits of the control means. WHAT WE CLAIM IS: -

1. Apparatus of the kind described including pairs of opposed clamp members movable with the transfer head and reIative thereto and one to the other, and clamp member actuating means operable, when the transfer means is aligned with the top layers of the pile preparatory to effecting movement of the top layer on to the transfer table, to actuate the clamp members independently to engage the sides of the layer next below the top layer in a manner such that, irrespective of the position of alignment of said next lower layer in relation to the other layers of the pile, said next lower layer is gripped between the clamp members in the position at which it is presented for engagement by the clamp members and is stabilised in that position during movement of the top layer on to the transfer table by the transfer means.

2. Apparatus according to Claim 1 wherein the transfer means comprises a sweep member supported by a shaft transverse to and mounted for reciprocation lengthwise of the transfer table by said operating means, and where in the sweep member is freely movable axially' of the shaft and is locatable relative to the transfer table by the clamping members of the pair thereof arranged to engage the sides of said next below layer which extend lengthwise of the transfer table.

3. Apparatus according to Claim 1 or Claim 2 including gripper means movable with the transfer head and comprising a fixed gripper and a movable gripper, and gripper means actuating means operable when the transfer means is aligned with the top layer of the pile preparatory to effecting movement of the top layer on to the transfer table to actuate the movable gripper to grip and hold between the grippers a pad supporting the top layer while the top layer is moved by the transfer means from the pad on to the transfer table.

4. Apparatus according to any one of Claims 1 to 3 including an index arm movable with the transfer head and pivotally mounted thereon, said arm being arranged to engage the top of the top layer of the pile, an elevator arm movable with the index arm and carrying a cam follower engageable with a cam track during movement of the transfer means towards the layer-receiving surface to raise the index arm out of engagement with the layer being moved by the transfer means, an operating arm pivotally mounted on the transfer head and movable by the elevator arm, to actuate a switch to initiate operation of the clamp member actuating means and said operating means, and a fixed stop engageable by the elevator arm to determine the lowermost position of the index arm.

5. Apparatus according to Claim 2 and Claim 4, wherein the index arm is freely rockable about said shaft.

6. Apparatus of the kind described substantially as herein described with reference to the accompanying drawings.