GB2191165A - De-lidding apparatus - Google Patents

Abstract

Tins, eg bread baking pans, are de-lidded by being conveyed past an upwardly inclined endless belt conveyor comprising belts 100,102 on either side, to the underside of which belts the lids 110 are drawn and held magnetically by a bank of permanent magnets 84,86 embedded in nylon casing 88 located to the rear of the conveyor belt reach to which the lids are held. <IMAGE>

Description

SPECIFICATION Improvements relating to de-lidding apparatus This invention relates to de-lidding apparatus, being apparatusforexamplefor removing the metal lids of baking tins of the type used for baking bread, wherein the baking tins are conveyed by machinery through baking plant on a continuous basis.

In the baking of bread, baking tins, being containers defining several, usually, four compartments for receiving gobs of dough to be baked into bread, are conveyed continuously through baking plant stations comprising for example a panner, a lidding apparatus, a baking oven, a de-lidding apparatus, a de-panner,followed by the return of the tins to the start ofthe sequence.

Various forms of machinery have been developed for removing the lids automaticallyfrom the baking tins, these being typically mechanical or magnetic.

The present invention is concerned with the removal ofthe lids from the tins by magnetic means in an advantageous and effective manner.

In one knownform of de-lidding apparatus which operates by magnetically attracting the lids away from the tins, a pair of endless chains carry magnetic pads which are pivotally mounted relative to the chains, andthe pads magneticallyattractthe lids into contact therewith as the chains are mved in synchronism with the conveyor carrying the iidded tin. The chains travel thereafter in a path which diverges from the means conveying the tin so that the lids are separated from the tins and subsequently are detached from the magnetic pads to complete the separation of the lids from the conveyor carrying the tins.

The present invention provides an alternative methodforthe magnetic attraction ofthe lids, and in accordance with the invention de-lidding apparatus comprises a lid conveyor operatively arranged in relation to a tin conveyor so that the lid conveyor may convey lids away from the tin conveyor, and wherein magnets are associated with the lid conveyor to cause the lids to be attracted into contact with one side of an operative reach ofthe lid conveyor, the magnets being located to the other side of said operative reach but being in fixed position so as not to move with said reach.

The said magnets preferably comprise permanent magnets arranged in two parallel banks on a conducting plate so that said magnets and the conducting plate, in conjunction with the respectve lids held by the conveyor reach, form a looped magneticfield providing strong attraction of the lids to the magnets and firm holding ofthe lids to the lid conveyor reach.

The magnets are preferably located spaced from the opposite side of the said reach so that there is an airgap between the magnets and the conveyorreach orthe lids eliminating any friction between the conveyor reach and the magnet.

The lid conveyor preferably comprises endless belting trained round a pairofspaced pulleys, one of which is driven, and the bank of magnets preferably extends in the space between the said pulleys.

The belting may be arranged sothatthere is an upper reach and a lower reach, the said lower reach forming the operative reach forthe picking up ofthe lids.

The said lower reach in use will be slightly upwardly inclined in relation to the conveyorforthe tins so as progressively to take the lids away from the tins. When the belting passes round the higher of the two pulleys and thereby takes the lids out of the influence of the magnetic attraction of the magnet banks, the lid will simplyfall awayfromthe reach for example onto another conveyor or into a storage location.

The said pulleys may be mounted in a channel member, and the lower of said pulleys may be mounted for position adjustment relative to the channelmembersothatthepulleycan be raised or lowered between an operative position in which the apparatus is adapted to pick up the lids from the tins, and an inoperative position in which the pulley is raised, and tins with lids which pass thereunderwill not in fact be de-lidded. This latter situation is often required when the lids have to remain with the tins.

The meansforsuspending and moving the lower pulley may comprise an aircylinderand atension spring, the arrangement being that when the apparatus is in use,thetension spring supports the weight of the lower pulley and indeed the channel memberwhich is in fact an arm swingable about the axis of the upper pulley, the air cylinder simply acting as a movement dampener, whereas when the apparatus is inoperative, the air cylinder is supplied with air under pressure lifting the lower pulleytothe out-of-use position.

The control means for the apparatus may ensure that when the prime mover or motor is driving to cause driving ofthe lid conveyor belts, a solenoid controlling the supply of air under pressure to the air cylinder is positioned to block the flow of pressure air to the cylinder and the respective sides ofthe cylinder are simply connected to atmosphere, through restrictive valves if necessaryto control dampening, whereas when the motor is stopped, the solenoid is positioned to permit air under pressure to be supplied to the side ofthe cylindercausing lifting ofthe lower pulley to the out-of-use position.

Because the lower pulley can in effect "float" during operation, asthe lids are initially attractedto the bank of magnetos and held bythe conveying belts, the lower pulley may in fact smoothly lift in orderto prevent any fouling ofthe lids with the moving tins.

The belt conveyorforthe lids is preferably arranged to move slightly slower than the tin conveyor, so that when a lid is attracted to the conveyor belts, the tin from which the lid is removed will be accelerated away from the lid which again enhances operation.

Becausethe magnet banks arefixed permanent magnets, and are not required to move with the conveyor belts, then a simple and effective arrangement is provided. It is particularly smooth in operation and high power magnets can be used because ofthe maintenance of an air gap between the magnets and the reach supporting the lid orthe lid supported by the reach. Also said lids can easily be detached from the reach when they are moved out of the influence of the magnets.

The magnets may be encased in a protective sheet or covering, suitably a casing of nylon or the like material which is non-magnetic in nature.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, wherein Figure lisa side view ofthe de-lidding apparatus according to the embodimentofthe invention; Figure2 is an end view ofthe apparatus of Figure 1 when viewed from the left hand side; Figure 3 is an end view of the apparatus of Figure 1 when viewed from the right hand side; and Figure4 is an enlarged end view of part ofthe apparatus as shown in Figure 2.

Referring to the drawings, in Figure 1 the reference numeral 10 indicates the line oftravel of a conveyor belt for baking tins having lids thereon, the direction of travel ofthe belt 10 being indicated by reference numeral 12. The line 14 indicatesthe line along which the top surfaces ofthe lids of the tinswill travel, and mounted above the conveyor 10 is the apparatus 16 of the present invention.

The apparatus comprises mainly an endless conveyor belt arrangement indicated by the numeral 18, and the conveyor belt arrangement has parallel reaches comprising an upper reach 20 and a lower reach 21. The endless conveyr 18 passes round pulley means in the form of lower pulley means 22 and upper pulley means 24 respectively having axes of rotation indicated by numerals 26 and 28. The said axes 26 and 28 are horizontal, and are arranged at right angles to the direction 12 of travel ofthetins.

The axis 26 is at a lower level than the axis 28 so that the reaches 21 and 20 in fact are inclined as shown.

The conveyor 18 travels in the direction indicated by arrows 30 and 32 respectively on the upper and lower reaches 20 and 21.

Referring nowto Figures 2 and 3, itwill beseen thatthe pulley means 24 comprises a pair of pulleys 24Aand24B,and likewise the pulley means 22 comprises a pair of puileys 22A and 22B, and in each case the pulleys are fast with a shaft 34 in the case of pulleys 24Aand 24B and 36 in the case of pulleys 22A and 22B. The shaft 34 is supported on a pair of side plates 38 and 40 of the apparatus which, as shown in Figure 1, are of inverted U-shape, and are anchored to a bed plate 42 by means of bolts or the like attached at fixing points 44.The shaft 34 is supported in the side plates 38 through bearings 46,48 and in fact shaft 34 is a drive shaft in that it receives power from a motor (not shown) which drives the shaft 50 (Figure 3) which is parallel to shaft 34 and is connected thereto by means of a sprocket and chain drive or sprocket and belt drive ofwhich the chain or belt is indicated by reference numeral 52.

Between the pulleys 24A and 24B is provided a U-shaped steel frame 54 which at the upper end in the vicinity of shaft 34 carries internally of the sides, bearings 56 and 58. The shaft 34 is rotatably located in said bearings.

At the lower end, the channel 54 as shown in Figure 2 is provided on the innerfaces of the sides with bearings 60 and 62 which are similarto bearings 56 and 58 and the shaft 36 passes rotatablythrough said bearings 60 and 62 and of course carries the pulleys 22A and 22B. By so providing this arrangement, the channel 54 can in fact be swung aboutthe axis 28, as indicated byarrow64sothatthe pulleys 22A and 22B can in fact be raised and lowered. The full line position shown in Figure 1 is the operational position of pulley means 22, whereas the position indicated by numeral 66isthe inoperative position.

The raising and lowering ofthe lower end of channel 54 is effected by means of an air cylinder 68 containing a piston to which is connected a piston rod 70. The cylinder 68 is pivotally mounted at72 to a bracket supported on the underside of a top plate 74 connecting the tops of the side plates 38 and 40.

At its lowerendthe piston 70 is pivotally connected at point 74 to a shaft 76 which extends between the sides of channel members 54 and is connected to such sides by means of brackets 78.

Atension spring 80 is coupled between the underside of top plate 74 and the said bracket so as to provide a means of supporting the lower end of the channel member 54.

As channel member 54 is of constant cross-section and as the axes 26 and 28 intersect the sides atthe same distance from the base of channel member 54, the said base is in fact inclined relative to conveyor 10 at the same angle as is the lower reach 21 ofthe conveyor 18.

To the underside of the base of channel 54, as shown best in Figure 4, is a mild steel spacer plate 81 on which is mounted a mild steel flux plate 82.

Adheredtothe underside of plate 82 are permanent magnet blocks 84 and 86, arranged in rows so as to provide two banks 84 and 86 of said magnets arranged as shown in Figure 1 along almost the entire length of the underside of the channel 54.

The permanent magnetic blocks are protected by means of a plastics material casing 88, which may conveniently be of nylon orthe like. The casing 88 is screwed to the flux plate 82.

Attached to the outside surfaces of the sides ofthe channel member 54, and towards the lower portions thereof are support brackets 90 oftheform shown in Figure 4. These brackets are L-shaped and have reinforcing webs 92 extending between the legs thereof. One of the legs is parallel to the side of the channel member, whilstthe other leg 94 is a right angles thereto and forms a ledge supporting guide channels 96 and 98. This construction is present at both sides of the channel member although only one side is shown in Figure 4.

The channel members 96 and 98 receive individual belts 100 and 102 (provided at each side of the channel member 54). There are therefore four belts 102 and 104which form the conveyor 18, andthese belts may be of conventional construction and having a V-section portion for fitting in the guides 96, 98.

The belts 100 and 102 are dimensioned so as not onlyto ride smoothly in the guides 96,98, but also to provide support surfaces 104,106 which are spaced from the lower surface 108 of the casing 88 so that when a iid, such as lid 110 shown in Figure 4 is held against the belts 100, 102 by the magnets 84,86, in factthere is no contact between the lid and the surface 108.

The operation ofthe apparatus will be largely understood from the foregoing, but briefly the operation is as follows. The tins with lids are conveyed by conveyor 10 in the direction of arrow 12 unto and pasttheapparatusshown in the drawings.

As each tin with its lid arrives in a position underthe pulley wheels 22A, 22B, the leading end of the lid comes underthe influence ofthe magnets 84,86, and the leading end is lifted into contact with the belts 100,102. The belts 100,102 are travelling at a linear speed somewhat less than the speed of conveyor 10 so that as the lids are held by the magnets 84, 86to the belts 100,102, so the tin accelerates awayfrom the lidtherebyto minimize possiblefouling or other problem. As the belts 100,102 and the conveyor 10 continueto move, so the lid is held to the belt 100, 102 andtravels upwardly atthe inclination ofthe lower reach ofthe conveyor 18 towards the pulley 24.

The lids are held in position by the magnetic attraction ofthe banks of magnets 84,86.

During the operation, the lids are magnetically attracted to and removed from the tins in turn, and they are held to the belts 100 and 102 during the travel along the lower reach of conveyor 18. When the lids reach a position underthe pulley 24, and as the movement of the conveyor 18 continues, so the lids progressively come less underthe influence of the magnet banks, and will simplyfall away from the belts 100, 102 with continued movement ofthese belts. The detached lids can be caught on another conveyor or in a collection zone as appropriate, and such means forms no part ofthe present invention.

During the operation of the apparatus as described, the air cylinder 68 is in fact inactive. That is to say the rod side of the piston is connected to atmosphere as is the crown side of the piston, but the crown side of the piston is connected to atmosphere through a restrictorvalvesothattheaircylinder68 can serve as a dampening means against excess of movement ofthe lower end of the channel member 54. In this condition,the spring 80 in effectsupports the lower end of the channel member 54, and therefore the lower end can "float" to some extent as the lids are being magnetically attracted as explained above. These lids are of a finite length, and the leading end as will be understood is attracted in the first instance to the magnet banks 84,86, and therefore the trailing end in effect pivots on the trailing end ofthe tin.Depending upon the geometry, this pivoting ofthe lid on the trailing end ofatin in fact may requirethe pulley means 22 andthe lower end ofthe channel 54to lift slightly so that the reach 21 ofthe conveyor 18 lies i n a I in alignmentwiththetop surface of the lid or in the plane ofthe lid so thatthere will be a smooth take-up ofthe lid on to the belts 100, 102. The utilisation ofthe spring 80 and air cylinder 68 permits units to take place.There is a supply of pressureairavailableto pressurisethe rod side of the piston of cylinder 68 when the motor driving the conveyor 18 is stopped, butwhilstthe motor 18 is running, a solenoid (not shown) is electrically energized which closes a valve blocking the flow of airto the cylinder 68. However, when the motor is stopped, the solenoid is de-energized, the valve is opened and pressure air is supplied to the piston side of cylinder68, causing the cylinder 68to contract and liftthe lower end ofthechannel 54to the position shown by reference 66. The tension spring 80 assists in the raising ofthe lower end ofthe channel 54to the inoperative position.

The apparatus described is smooth in operation and is effective for holding lids to the lower reach of the conveyor 18. The lids can be readily detached by the means employed, and friction is kept to a minimum in that the lid does not come into frictional contact with the magnet or the casing housing the magnets but is held to contact only against the belts which run in the guides 96 and 98.

It will be appreciated that the peripheries of the pulleys 22A, 22B, 24A, 24B are grooved in orderto receivetheVshaped belts 100 and 102.

Claims (12)

1. De-lidding apparatus comprising a lid conveyor operatively arranged in relation to a tin conveyor so that the lid conveyor may convey lids away from the tin conveyor, and wherein magnets are associated with the lid conveyor to cause the lids to be attracted into contact with one side of an operative reach of the lid conveyor, the magnets being located to the other side of said operative reach but being in fixed position so as not to move with said reach.

2. Apparatus according to Claim 1, wherein the said magnets comprise permanent magnets arranged in two parallel banks on a conducting plate so that said magnets and the conducting plate, in conjunction with the respective lids held by the conveyor reach, form a looped magnetic field providing strong attraction of the lids to the magnets and firm holding ofthe lids to the lid conveyor reach.

3. Apparatus according to Claim 2, wherein the magnets are located spaced from the opposite side ofthesaid reach sothatthere is an airgap between the magnets and the conveyor reach orthe lids eliminating any friction between the conveyor reach and the magnets.

4. Apparatus according to any preceding claim, wherein the lid conveyor comprises endless belting trained round a pair of spaced pulleys, one ofwhich is driven, and the magnets lying in the space between the said pulleys.

5. Apparatus according to Claim 4, wherein the belting is arranged so that there is an upper reach and a lower reach, the said lower reach forming the operative reach for the picking up of the lids.

6. Apparatus according to Claim 5, wherein the said lower reach in use is slightly upwardly inclined in relation to the conveyor for the tins so as progressively to take the lids away from the tins.

7. Apparatus according to Claims4,5or6, wherein the said pulleys are mounted in a channel member, and the lower of said pulleys is mounted for position adjustment relative to the channel member so that the pulley can be raised or lowered between an operative position in which the apparatus is adapted to pick up the lids from the tins, and an inoperative position in which the pulley is raised, and tins with lids which pass thereunder will not in fact be de-iidded.

8. Apparatus according to Claim 7, wherein the means for suspending and moving the lower pulley comprises an air cylinder and a tension spring, the arrangement being that when the apparatus is in use, the tension spring supports the weight of the lower pulley and indeed the channel memberwhich is in fact an arm swingable aboutthe axis ofthe upper pulley, the air cylinder simply acting as a movement dampener,whereas when the apparatus is inoperative, the air cylinder is supplied with air under pressure lifting the lower pulley to the out-of-use position.

9. Apparatus according to Claim 8, wherein the control meansforthe apparatus ensuresthatwhen the prime mover or motor is driving to cause driving of the lid conveyor belts, a solenoid controlling the supply of air under pressure to the air cylinder is positioned to blockthe flow of pressure airto the cylinder and the respective sides of the cylinder are simply connected to atmosphere.

10. Apparatus according to any of Claims 4to 9, wherein the belting comprises a plurality of V sectioned belts which run in V grooves on said pulleys and in V grooved guide plates holding the belts in spaced relationship with said magnets.

11. Apparatus according to any preceding claim, wherein the magnets are encased in a protective sheet or covering, suitably a casing of nylon orthe like material which is non-magnetic in nature.

12. De-lidding apparatus substantially as hereinbefore described with reference to the accompanying drawings.