GB2124993A - Palletiser - Google Patents

Abstract

A palletiser comprises a horizontally reciprocable stripping apron 62, means including a pusher 16 for forming an array of articles on the apron 62, a back stop 20 for holding the array of articles, e.g. kegs or drums, in position as the apron 62 is withdrawn, and a lift mechanism 24 for lifting a pallet to a position immediately beneath the apron to receive the articles. The lift mechanism comprises two vertically movable lift members 120 adapted to engage and lift the pallet, a horizontally movable drive member in the form of a carriage 140 having ramps 142 which engage rollers 144 on the lift members 120 so that the lift members are moved by a camming action when the carriage 140 is moved horizontally. This enables a very precise positioning of the pallet. Sensing means may be provided to determine when the upper face of the pallet reaches the correct position. The palletiser may have two parallel conveyors 30, 32 adapted to move two rows of kegs, etc. simultaneously to a transfer station adjacent the stripping apron 62 and a pusher 16 for pushing the two rows of kegs simultaneously onto the stripping apron. <IMAGE>

Description

SPECIFICATION Palletiser This invention relates to palletisers.

More particularly, the invention relates to palletisers for loading articles such as kegs or drums onto a pallet.

There are known palletisers which comprise means for forming an array of articles on a horizontally reciprocable stripping apron, and a pallet conveyor for moving an empty pallet to a position beneath the stripping apron so that when the stripping apron is withdrawn from beneath the array of articles the articles are deposited onto the pallet.

A problem which can arise with such palletisers is that pallets can vary in height, and the relative vertical positions of the pallet conveyor and the stripping apron must be arranged to accommodate the greatest height of pallet expected. This means that, for pallets of less than this height, articles must fall through a greater distance onto the pallet when the stripping apron is withdrawn. Since falls of as little as a few centimetres can cause damage to certain articles or to pallets, this is undesirable.

It is an object of this invention to provide an improved palletiser.

This invention consists in a palletiser for loading articles onto a pallet, comprising a horizontally reciprocable stripping apron, means for forming an array of articles on the stripping apron, means for holding the array of articles in position as the stripping apron is withdrawn from beneath them, a conveyor for moving an empty pallet to a station below the stripping apron, and a lift mechanism for lifting the pallet at the station to a position immediately beneath the stripping apron, the lift mechanism comprising at least one vertically movable lift member adapted to engage and lift a pallet at the said station, a horizontally movable drive member and co-operating cam means on the lift member and drive member arranged so that horizontal movement of the drive member in one direction effects upward movement of the lift member through engagement between the co-operating cam means, and drive means for effecting horizontal movement of the drive member.

Preferably, the co-operating cam means comprises at least one ramp fixed to the drive member and having a face inclined to the horizontal and at least one co-operating roller mounted on the lift member and running on the said face.

The drive means may comprise a motor driving a pinion engaging a rack fixed to the lift member.

Advantageously, two lift members are provided, one positioned on each side of the pallet conveyor.

The lift mechanism ofthis invention allows accurate vertical positioning of the pallet beneath the stripping apron, so that the distance through which articles fall onto the pallet can be minimised.

The apparatus includes suitable sensing means, for example using a lamp and photoelectric cell, to sense when the upper face of a pallet has reached the desired position immediately beneath the stripping apron.

Another disadvantage of known palletisers is that they can be relatively slow in operation.

According to another aspect of this invention, there is provided a palletiser for loading an array of articles in two rows on a pallet, comprising a horizontally reciprocable stripping apron, two parallel conveyors adapted to move two rows of articles simultaneously to a transfer station adjacent the stripping apron, pusher means for pushing the two rows of articles simultaneously onto the stripping apron, and means for holding the array of articles as the stripping apron is withdrawn from beneath them thereby to deposit the array of articles onto a pallet positioned beneath the stripping apron.

In one form of the invention, the palletiser is used to load an array of four kegs or other cylindrical articles onto a pallet.

By transferring the two rows of articles simultaneously from the conveyors directly to the stripping apron, the speed of operation of the palletiser can be considerably increased.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 its a diagrammatic plan view of a palletiser in accordance with the invention, Figure 2 is a diagrammatic side elevation of the palletiser, Figure 3 is a plan view of a pusher mechanism of the palletiser, Figure 4 is a side elevation of the pusher mechanism, Figure 5 is a section on line V-V of Figure 4, Figure 6 is a plan view of a stripping apron assembly of the palletiser, Figure 7 is a side elevation of the stripping apron assembly, Figure 8 is a plan view of a back stop assembly of the palletiser, Figure 9 is a side elevation of the back stop assembly, Figure 10 is a plan view of a pallet lift mechanism of the palletiser, Figure l l is a side elevation of the pallet lift mechanism, showing the lift in the lowered position, Figure 12 is a side elevation of the pallet lift mechanism, showing the lift in the raised position, and Figure 13 is a section on line XIII-XIII of Figure 12.

Referring to the drawings, a palletiser for loading an array of four kegs on to a pallet comprises a main frame 10, a keg infeed conveyor 12 on which kegs are moved to a transfer station 14, a pusher mechanism 16 for pushing an array of kegs from the infeed conveyor 12 to the apron plate of a stripping apron assembly 18, a retractable back stop 20 for holding an array of kegs as the stripping apron is withdrawn, a pallet conveyor 22 for moving an empty pallet to a position beneath the stripping apron and for moving a loaded pallet from that position, and a pallet lift mechanism 24 for raising each pallet to a position immediately beneath the apron.

The keg infeed conveyor 12 comprises two parallel driven chain conveyors 30 and 32 on which two pairs of kegs can be moved simultaneously to the transfer station 14. Movement of the kegs is controlled by twin escapements 34 and by two pairs of retractable stops 36 positioned on the two conveyors 30 and 32 immediately adjacent the transfer station. To facilitate lateral movement of an array of kegs from the conveyors 30 and 32 at the transfer station onto the stripping apron, two series of rollers 38, each rotatable about a horizontal axis parallel to the longitudinal axes of the conveyors 30 and 32, are positioned between and adjacent the chains of the conveyors at the transfer station.Each series of rollers 38 is carried by a respective sub-frame 40 pivoted at one end about a horizontal axis to the main frame 10 of the apparatus, and movable between a lowered position in which the rollers are below the upper faces of the chains and a raised position in which the rollers project above the chains. Each sub-frame 40 can be raised by means of an air cylinder 42 acting between the main frame 10 and the sub-frame 40 to lift the kegs slightly from the conveyor chains and allow them to move laterally on the rollers 38.

The pusher mechanism 16 comprises a vertical pusher plate 44 suspended from a carriage 46.

Carriage 46 consists of a rectangular frame of two longitudinal members 48 and two cross-members 50. The carriage is supported by four rollers 52 rotatably mounted on the longitudinal members 48 and running in tracks formed in upper horizontal channel-section members 54 of the main frame 10.

The carriage is guided laterally by means of four wheels 56 rotating about vertical axes and running against vertical faces of the main frame members 54.

The carriage is movable by means of a double-acting air cylinder 58 acting between the main frame 10 and a bracket 60 fixed to the front cross-member 50 of the carriage.

The stripping apron assembly 18 comprises a horizontal, flat apron plate 62 suspended from a horizontally movable carriage 64. The carriage 64 has a frame consisting of two side members 66 and a cross-member 68, and is supported by six rollers 70 mounted three on each side member 66 and running in tracks in the upper horizontal members 54 of the main frame 10. The carriage 64 is guided laterally by six wheels 72 rotating about vertical axes and running against vertical faces of the main frame members 54. Three pairs 74,76 and 78 of vertical legs are attached at their upper ends to the side members 66 of the carriage 64 and at their lower ends to two longitudinal members 80. The apron plate 62 is fixed to the lower faces of the longitudinal members 80, which extend along two sides of the plate 62.An L-section strengthening member 82 is fixed to and extends transversely across the apron plate 62 near the end remote from the transfer station 14.

The apron assembly 18 also includes two side guides 84, each extending along one side of the apron plate 62 and being of sufficient height to engage the sides of kegs on the apron plate. Each side guide 84 consists of a series of parallel rollers 86, mounted for rotation about a vertical axis in a frame 88 fixed to two of the legs 74 and 76 of the assembly. The roller 90 at the end nearest the transfer station 14, which may engage a keg to guide it into position in the apron plate 62, may be covered with suitable plastics, such as polyurethane.

The apron assembly 18 is movable by means of two double-acting air cylinders 92 acting between the main frame 10 and brackets 93 fixed to the upper side members 66 of the carriage 64. The assembly 18 is movable between a projected position in which the apron plate 62 is adjacent the transfer station 14 so that it can receive an array of kegs pushed from the keg infeed conveyor 12, and a retracted position in which the apron plate 62 is pulled clear of the array of kegs to deposit the kegs onto a pallet on the pallet lift mechanism 24.

The retractable back stop 20 for holding an array of kegs as the apron plate 62 is retracted comprises a vertical rectangular plate 94, faced with polyurethane, positioned to engage kegs on the apron plate at about their mid-height. The plate 94 is mounted on a horizontally movable carriage 96 consisting of two side members 98 and two crossmembers 100. The side members 99 are of channel section and run on rollers 102 mounted on horizontal members 104 of the main frame 10. The carriage 96 is movable through a short distance by means of a double-acting air cylinder 106 which acts between the main frame 10 and one arm 108 of a bell-crank lever 110 pivoted to the main frame 10. The other arm 112 of the bell-crank lever is pivoted to one end of a compression link 114, the other end of which is pivoted to a lug 116 fixed to one cross-member 100 of the carriage 96.When the stop plate 94 is in the projected position, the compression link 114 and the arm 112 are horizontally aligned, so that the force exterted in use on the stop plate by the kegs during retraction of the apron plate 62 is not transmitted to the air cylinder 106. Actuation of the air cylinder 106 rotates the bell-crank lever 110 to move the carriage 96 and thereby retract the stop plate 94 out of engagement with the kegs.

The pallet conveyor 22 comprises a horizontal chain conveyor extending through the apparatus in a direction at right angles to the direction of movement of the stripping apron assembly 18. The pallet lift mechanism 24 comprises two lift members 120 arranged one on each side of the pallet conveyor 22.

Each lift member 120 consists of an elongate member of an inverted L-shape in cross-section, having a horizontal upper portion 122 joined to a vertical side portion 124. Two vertical end plates 126 are formed at the ends of the lift member. The upper portion 122 is positioned so that it can engage one of the lower runners of a pallet on the pallet conveyor 22. Each lift member 120 is movable vertically, and is prevented from lateral movement by means of a retaining strip 128 positioned against the inner face of the vertical portion 124 of the lift member and connected to a side plate 130 by means of bolts 132 passing through vertically extending slots in the vertical portion 124. The side plate 130 is fixed to the main frame 10 of the apparatus. Plastics wear strips 134 are interposed between the lift member 120 and side plate 130. The lift member 120 is held against longitudinal horizontal movement by means of two rollers 136 rotatably mounted on the side plate 130 and engaging the vertical end plates 126 of the lift member.

Vertical movement of each lift member 120 is effected by horizontal movement of a carriage 140 having two ramps 142 which engage rollers 144 mounted on the lift member. Each carriage 140 consists of an elongate beam having a vertical web 146 joining an inwardly extending upper horizontal flange 148 and an outwardly extending lower horizontal flange 150. The upper flange 148 rests on two freely rotatable rollers 152 each mounted on the side plate 130, so that the carriage can run horizontally on the rollers. A plastics wear strip 154 is fixed to the underside of flange 148. The beam is retained laterally by a retaining member 156 fixed to the main frame 10 and engaging the vertical web 146 of the beam, a plastics bearing strip 158 being interposed between the retaining member and the web 146.The two ramps 142 are each fixed to the upper flange 148 and each has an upper face inclined at an angle of approximately 16 to the horizontal.

Each ramp 142 engages a roller 144 freely rotatably mounted on the corresponding lift member 120.

Each roller 144 is mounted in a bearing block 160 welded to the vertical portion 124 of the lift member.

Horizontal movement of the carriage 140 to the left as shown in the drawings thus effects upwards vertical movement of the lift member 120, the rollers 144 running along the inclined faces of the ramps 142. Movement of the carriage 140 in the opposite direction allows the lift member 120 to move downwards under its own weight and the weight of a pallet resting on the lift members.

Horizontal movement of the two carriages 140 is effected by means of an electric motor 162 driving, through suitable gearing and a chain drive 163, a horizontal drive shaft 164 rotatably mounted in bearings 166 fixed to the side plate 130 of main frame 10. The drive shaft 164 extends transversely beneath both carriages 140 and carries two pinions 166 each engaging a respective rack 168 fixed to the lower flange 150 of each of the carriages 140. The motor 162 is controlled by suitable circuitry, to enable the lift members 120 to be accurately positioned. A lamp 170 and photoelectric cell 172 are arranged to detect the upper face of a pallet on the pallet lift mechanism when the pallet reaches a position just below the apron pallet 162.Other photoelectric or electromechanical sensing devices may be provided in well-known manner to control the operations of the various components of the apparatus.

A retractable stop 174, which may be of wellknown form, is positioned in the pallet conveyor 22 to arrest each empty pallet in the correct position beneath the stripping apron 162, and to release each pallet after the array of kegs has been deposited on it.

In operation of the palletiser, four kegs 200 are moved simultaneously on keg infeed conveyor 12 to the transfer station 14. The rollers 38 are raised and pusher mechanism 16 actuated to push the four kegs simultaneously onto the apron plate 162 of the stripping apron assembly. At the same time an empty pallet 201 is moved into position below the stripping apron on conveyor 22. The pallet lift mechanism 24 is actuated to lift the empty pallet from the conveyor and raise it until the photoelectric sensor indicates that the upper face of the pallet is just beneath the apron plate 162. The retractable back stop 20 is moved to its projected position, and the carriage 64 of the stripping apron assembly 18 is moved to withdraw the apron plate 162 from beneath the kegs, so that the kegs are deposited onto the pallet.During this movement, the side guides 84 of the apron assembly 18 prevent sideways movement of the kegs. After the kegs have been deposited on the pallet, the lift mechanism 24 is operated to lower the loaded pallet onto the pallet conveyor 22, and the stop 174 is retracted to allow the loaded pallet to be discharged on conveyor 22.

The carriage 64 of apron assembly 18 is returned to its initial position to receive the next array of kegs which have in the meantime been moved to the transfer position 14, and the cycle is repeated.

The pallet lift mechanism 24 ensures that the kegs have to fall through only a short distance onto the pallet, so that the risk of damage to the kegs or pallet is eliminated and the noise generated is much reduced. The construction of the lift mechanism enables each pallet to be lifted quickly and accurately into position and avoids the risk of jamming which might occur, for example, with a lifting mechanism employing screw jacks.

The use of twin keg infeed conveyors and of a pusher mechanism pushing four kegs simultaneousliy from the infeed conveyors directly onto the pallet stripping apron considerably increases the overall speed of the palletiser, which can be made fully automatic in operation.

It will be appreciated that modifications could be made in the described embodiment. For example, other drive means such as rack and pinion mechanisms could be used to move the pusher plate and the stripping apron assembly, in place of the air cylinders described. The side guides 84 on the stripping apron assembly may be mounted so as to be movable towards and away from one another, for example by means of air cylinders, the guides being moved towards one another to engage the kegs on the stripping apron, to counter any lateral movement of the kegs which may occur as they are pushed onto the stripping apron.

The palletiser could be used to handle articles other than kegs, particularly other cylindrical or barrel shaped articles.

Claims (10)

1. A palletiserfor loading articles onto a pallet, comprising a horizontally reciprocable stripping apron, means for forming an array of articles on the stripping apron, means for holding the array of articles in position as the stripping apron is withdrawn from beneath them, a conveyor for moving an empty pallet to a station below the stripping apron, and a lift mechanism for lifting the pallet at the station to a position immediately beneath the stripping apron, the lift mechanism comprising at least one vertically movable lift member adapted to engage and lift a pallet at the said station, a horizontally movable drive member and cooperating cam means on the lift member and drive member arranged so that horizontal movement of the drive member in one direction effects upward movement of the lift member through engagement between the co-operating cam means, and drive means for effecting horizontal movement of the drive member.

2. A palletiser as claimed in claim 1, in which the co-operating cam means comprises at least one ramp member fixed to one of said drive member and lift member and having a face inclined to the horizontal and a roller mounted on the other of said drive member and lift member and running on the said face.

3. A palletiser as claimed in claim 2, in which the drive means comprises a motor driving a pinion rotatable about a fixed axis and engaging a rack fixed to the drive member.

4. A palletiser as claimed in any preceding claim, in which two lift members are positioned one on each side of the pallet conveyor.

5. A palletiser for loading an array of articles in two rows on a pallet, comprising a horizontally reciprocable stripping apron, two parallel conveyors adapted to move two rows of articles simultaneously to a transfer station adjacent the stripping apron, pusher means for pushing the two rows of articles simultaneously onto the stripping apron, and means for holding the array of articles as the stripping apron is withdrawn from beneath them thereby to deposit the array of articles onto a pallet positioned beneath the stripping apron.

6. A palletiser as claimed in claim 5, and adapted to load two rows each of two generally cylindrical articles onto a pallet so that the articles stand upright on the pallet, in which there are provided guides on each side of the stripping apron parallel to the direction of movement of the articles onto the stripping apron, the guides being positioned to prevent movement of the articles transversely to said direction as the articles are pushed onto the pallet.

7. A palletiser as claimed in claim 6, in which the guides are movable with the apron as the apron is withdrawn from beneath the articles.

8. A palletiser as claimed in claim 7, in which the guides and stripping apron are suspended from a carriage mounted for horizontal movement at a level above the stripping apron higher than the height of articles to be palletised.

9. A palletiser as claimed in any one of claims 6 to 8, in which each of said guides comprises a series of rollers mounted for rotation about parallel vertical axes.

10. A palletiser constructed, arranged and adapted to operate substantially as described with reference to, and as shown in, the accompanying drawings.