GB2082536A - Improvements in article handling equipment - Google Patents

Abstract

A magnetic de-lidder for removing lids (28) from baking pans (12) has a belt of pot-shaped magnets (19) supported by carriers (21) on chain links. Each carrier (21) has a laterally extending support pin (26) whose ends are engaged by respective support discs (25) so that adjacent magnets (19) can tilt as shown to bring them into alignment and thereby in face-to-face contact with a lid (28). Mobility of the magnet carriers is thereby obtained without the need to provide excessive chain slackness. The support discs (25) are mounted on a frame (31) which is pivotally mounted (at 16) to provide for height adjustment. The weight of the frame and the structure thereon is carried partially by tension springs and partially by an adjustably fixed abutment (35), the arrangement allowing the frame to yield upwardly as it rides over the pans. <IMAGE>

Description

SPECIFICATION Improvements in article handling equipment The present invention relates to a magnetic pickup device for picking up articles by means of magnets and transferring them from one place to another.

Such a device is described in British Patent No.

1360613 wherein the preferred embodiment in intended as a magnetic de-lidder for use in bakeries and the like for removing lids from pans such as baking pans. The magnets are supported on two parallel endless chains. Since it is not uncommon for baking pans to be quite large (they may be designed to receive two or more loaves side by side) the lids are correspondingly large, and in orderthatthe lids will be adequately held by the magnets of the delidder, the pole shoes of the magnets should engage correspondingly portions of the lid distributed over the full length and breadth of the lid.The length of the lid can be accommodated by arranging for the bakery pans to be disposed transversly of their di rec- tion of conveyance beneath the de-lidder, but even their width can be sufficiently large to create problems in arranging for the pole shoes of the magnets to remain in engagement with a sufficiently large portion of the width of the lids while the lids are being carried over an arcuate path of travel defined by sprocket wheels about which the chains are entrained.

A simple solution to this problem is to allow the endless chains to run very slack so that the chain links can tilt on the sprocket wheels. This allows two adjoining magnets engaged by one lid to remain in alignment with one another and thereby in full face to face engagement with the lid as the chains pass over the arcuate path of travel. A somewhat more elegant solution to the problem is described in British Patent No. 1425838. This involves carries for the magnets being freely pivoted to the supporting chain of the de-lidder. This enables two sets of magnets to remain in engagement with a pan lid over its width. However the de-lidder described in this prior patent is noisy in operation due to the magnet carriers being free to swing and the mobility ofthe magnet carriers restricts the weight of the magnets which it is practical to use.

An object of the present invention is to provide a further improved means for allowing more than one set of pole shoes to remain in engagement of the pan lid over an arcuate path oftravel over a magnetic pick-up device.

The present invention resides in a magnetic pickup device for picking up flat articles by means of magnets and transferring them from one place to another, comprising at least one endless chain incorporating magnet carners which are formed by or are rigidly fixed with respect to limbs of the chain, the magnets being fixedly mounted on said carriers, an arcuate support extending along an arcuate portion of the path of travel of the endless conveyor and a pivot on each carrier and engageable with the arcuate support such that at least two adjoining magnet carriers can tilt about their respective pivots and so become aligned with one another to allow the associated magnetic pole faces to remain in engagement with a flat article picked up by the respective magnets while such article is carried along said arcuate path portion.

By arranging the pivots substantially centrally of the respective magnet carriers, it is possible for the latter to tilt without having to provide significant extra siackness in the chains.

With the use of magnetic de-lidders, there is the danger of damage to the de-lidder or to the lid if the de-lidder is adjusted to the incorrect height above the conveyorforthe baking pans. Small variations in the heights of the pans could also cause problems.

The present invention includes a magnetic delidder having a pick-up structure which includes a moving band of magnets and which is movably mounted with its weight at least partially counterbalanced, preferably by a spring.

By this means, the pick-up structure can easily lift to ride over any obstruction it may encounter, e.g., due to incorrect height adjustment or due to the presence of a baking pan of the wrong size.

The invention is further described by way of example by reference to the drawings in which Fig. lisa diagrammatic side elevation of a magnetic pick-up device according to the present invention, Fig. 2 is a section on the line ll-ll of Fig. 1, Fig. 3 is a plan view to a larger scale showing a detail of the device, Fig. 4 is a section on the line IV-IV of Fig. 3, Fig. 5 is a diagrammatic side elevation of the device of Fig. 1 in a different state of adjustment, and Fig. 6 is a section on the line VI-VI of Fig. 5.

Referring first in Figs 1 and 2, a de-lidder 10 for use on a bakery or the like is disposed above a conveyor 11 for baking tins 12 which are traversed in the direction of the arrow 13 to a de-lidding station 14. The de-lidder 10 comprises a pick-up structure 15 whose frame 31 is indicated diagrammatically and which is hingedly mounted at an axis 16 on uprights which are not shown and which are interconnected by a bridge 32. The frame supports two endless belts 17 and 18 of pot-shaped magnets 19.

As indicated in Figs. 3 and 4, each belt comprises a chain 20 which incorporated magnet carriers 21.

Each magnet carrier 21 comprises tabs 22 which extend laterally from respective chain links 23 between adjacent chain link hinges 30. The magnet carrier is thereby effectively part of or constitutes a chain link. A respective pot-shaped magnet 19 is secured by a mounting plate 1 9a to the tabs 22. The mounting plates 19a may be omitted if the magnets have sufficient mechanical strength.

The chains 20 are entrained about driven sprocket wheels 24 which are rotatable about the axis 16. The chains also pass around an arcuate path around pairs of relatively large diameter support discs 25 for which purpose each carrier 21 is provided centrally thereof with a laterally extending support pin 26 whose end portions engage the outer peripheries of the discs 25. The pins 26 are rigidly fixed in apertures in the links 23. The tooth pitch of the sprocket wheels 24 is half that of the chains 20 so that the hinge rollers of the chains enter every second tooth gap, whereby the central portions of the pins 26 enterthe intervening tooth gaps and are not fouied by the sprocket teeth. The discs 25 are freely rotatable about an axis 27 in the frame.Thus the chains 20 are not themselves supported by their hinges 30 as the respective chain links traverse the arcuate path about the axis 27 but the carriers 21 are tiltably or rockably supported on the discs 25 by the support pins 26.

In operation, the sprocket wheels 24 are driven so that the belts 17 and 18 of magnets move in synchronism with the conveyor 11. At the de-lidding station 14, the pot-shaped magnets are brought into engagement with lids 28 freely resting on the pans 12 and lift the lids from the pans. As can be seen in Fig. 2, the lids 28 extend transversely to the direction of conveyance of the pans so that the magnets 19 on the two belts of magnets 17 and 18 engage the lids at points well spaced longitudinally of the lids. However, as can be seen in Fig. 1, the lids 28 have an appreciable width such that two magnets 19 engage each lid widthwise. The rockability of the carriers 21 enable two magnets 19to remain in engagement with one lid 28 widthwise thereof so that each lid is securely held by the de-lidder.The lids are carried along the arcuate path and are turned over by the de-lidder 10. In their inverted state, they are stripped from the magnets 19 by means of stripper wheels 29 and are then pushed on to a discharge conveyor 30 by which the inverted lids are carried away in a direction transverse to the direction of travel of the tin conveyor 11. Alternatively the discharge conveyor 30 could convey the lids in a direction opposite to the direction of the arrow 13.

The illustrated de-lidder is of simple construction since it is no longer necessary for the magnet supports to be pivoted to or otherwise moveably mounted on the chains. The links of the chains can themselves be deflected or rocked in the same manner shown in Fig. 1 to allow two adjacent carriers 21 to remain in alignment whilst traversing the arcuate path, thereby allowing two magnets 19 to remain in engagement with a flat pan lid 28 widthwise thereof.

Since the magnet carriers are not freely pivoted to the chains, it is practical to use relatively large permanent magnets 19 with good gripping power. Also noise and wear are reduced.

For the purpose of height adjustment, the frame 31 can be swung about the pivot point 16 to raise and lower the axis 27 relatively to the tin conveyor 11.

This enables the device to be adjusted to conform to different sizes of tins.

As shown in Figs. 5 and 6, the weight ofthe pick up structure 15 is taken by springs 33 acting in con junction with links 34. The two links 34 are pivoted at one end to a rod 35 and at their other end to a rod 36.

The tension springs 33 are hooked at one end 3 around the rod 36, which slides in slots 37 in the frame, and a screw jack 38 acts between the rod 35 and the bridge 32. The links 34 are thereby placed under compression. The other ends 39 are hooked around a support (not shown) which is adjustably mounted on the frame 31.

The height adjustment is effected at the screw jack 38, the pick-up structure 15 being shown in Fig. Sat an adjustment position too low for the pans 12.

However the weight of the structure 15 is taken up by the springs 33 acting in conjunction with the links 34, so that the structure can readily yield upwardly as it rides over the pans 12, as shown in Fig. 1 without damaging the pans or the pick-up structure. The rod 36 slides along the grooves 37 as the structure 15 is lifted. The spring tension can be adjusted by the above mentioned support so that the desired proportion of the weight of the structure 15 is taken by the springs.

With the rod 36 resting against the right hand ends of the slots 37, adjustment of the jack 38 raises or lowers the structure 15 without affecting the spring tension.

Claims (15)

1. A magnetic pick-up device for picking up flat articles by means of magnets and transferring them from one place to another, comprising at least one endless chain incorporating magnet carriers which are formed by or are rigidly fixed with respect to links of the chain, the magnets being fixedly mounted on said carriers, an arcuate support extending along an arcuate portion of the path of travel of the endless chain and a pivot on each carrier and engageable with the arcuate support such that at least two adjoining magnet carriers can tilt about their respective pivots and so become aligned with one anotherto allow the associated magnetic pole faces to remain in engagement with a flat article picked up by the respective magnets while such article is carried along said arcuate path portion.

2. A device as claimed in claim 1, in which each magnet carrier comprises tabs extending laterally oppositely from the respective chain links, the magnets being attached at least indirectly to said tabs.

3. A device as claimed in claim 2, in which each magnet is secured via a mounting plate to the respective tabs.

4. A device as claimed in claim 1,2 or 3, in which the pivot comprises laterally oppositely outwardly extending support pin portions and the arcuate support comprises two parallel discs arranged so that their peripheries are engaged by respective ones of the support pin portions.

5. A device as claimed in any of claims 1 to 4, in which each pivot comprises a support pin which extends laterally through the respective chain links.

6. A device as claimed in any preceding claim, in which the endless chain is entrained around a drive sprocket.

7. A device as claimed in claims 5 and 6, in which the tooth pitch of the drive sprocket is half the pitch length of each chain link.

8. A device as claimed in claim 6 or7, in which the arcuate support is mounted on a frame which is itself mounted for pivotal movement about the axis of the drive sprocket to provide height adjustment of the device.

9. A device as claimed in claim 6,7 or 8, in which at least one stripper wheel of larger diameter than the drive sprocket is arranged coaxially ofthe drive sprocket for stripping articlesfrom the magnets.

10. A magnetic de-lidder device having a pick-up structure which includes a frame and a moving band of magnets supported on the frame and which is movably mounted with its weight at least partially counterbalanced.

11.. A device as claimed in any of claims 1 to 9, in which the arcuate support is on a frame which is movably mounted to provide height adjustment of the device and the weight of the frame and the structure thereon is at least partially counterbalanced.

12. A device as claimed in claim 10 or 11, in which at least one spring provides the counterbalance force.

13. A device as claimed in claim 12, in which the spring acts between the frame and a transverse rod which is slidably guided in at least one slot in the frame and at least one link is disposed between an adjustably fixed support and the rod.

14. A device as claimed in claim 13, in which the spring is a tension spring.

15. A magnetic pick-up device constructed and adapted to operate substantiaily as herein described with reference to and as illustrated in the drawings.