GB2193181A - Lidding apparatus - Google Patents

Abstract

Lidding apparatus for applying lids 30, 32 to baking tins 36, 38 comprises a conveyor 34 for the tins and roller decking 10 which is above the conveyor along which the lids are fed. Each lid reaches the end of the decking from which it is removed by a tin moving with the conveyor. The feed of the lids to the decking is controlled by a series of lid engaging latches 50, 54 and tin presence detectors 51, 52, 53 such that the pressure of tins in certain positions eg for engagement with the lid, causes the withdrawal of a latch eg 50. The latches engage the tracking inside edges of skirts on the lids. <IMAGE>

Description

SPECIFICATION Lidding apparatus This invention concerns lidding apparatus for the application of lids to baking tins. The lids of baking tins comprise essentially a plate, usually of rectangular construction, having a rim therearound, so that when the lid is supplied to the tin, the rim will overlap the top edge of the tin.

In known lidding apparatus, the lids are fed one by one by a conveying means towards a lid application station. The conveying means is in fact essentially conveyor decking extending in the same direction as and above a conveyor carrying the tins, but the decking is inclined downwardly so that the lids will feed downwardly towards the tin conveyor, and the lids will be married to the tins one by one as the tins and lids are conveyed. In the known lidding apparatus, the first lid from the queue of lids on the decking is held at its leading edge by friction restraining means, but the leading edge is positioned so that the rim at said leading edge will be engaged by the leading edge of the advancing tin located thereunder and in fact the advancing tin following engagement with said leading edge of the rim withdraws the lid from the decking against the friction restraint.When the lid has been thus removed, the next lid is moved into position and this is removed by the next tin and so on.

Because of the nature of the friction restraining means, it is important that the tin lids do not become distorted or buckled, because the effective friction restraining is based upon the dimensions of the lids remaining within relatively narrow tolerances, and indeed to this end, it is recommended that the lids used with a lidding apparatus of the conventional construction as described above, in fact be strengthened in the region of the lid rim.

The present invention concerns an improved form of lidding apparatus which does not require the lid dimensions to remain within such narrow tolerances, and in accordance with the invention, the lidding apparatus comprises feed decking along which the lids are fed one by one to be married up with tins being conveyed one by one under the decking, wherein there is latch means for holding the first lid on the decking, such latch means being arranged to engage the inside of the lid rim at the trailing end thereof, such latch means being released upon the detection of the arrival of a tin to be lidded whereby release of the latch means permits the first lid on the decking to be released and to be taken up by the tin to close the tin.

A second latch means is preferably provided in order to engage the inside of the rim of the second lid at the trailing end thereof, and there is further detection means operable to cause release of the second latch only when release of the first lid in the decking has been detected.

The lids are preferably fed from the decking under gravitational forces but again the leading edge of the rim would be located so as to lie in the path of the leading edge of the tin to which it is to be applied so that the tin will assist in taking the first lid away from the decking.

The apparatus may comprise first detection means for detecting the arrival of a tin to be lidded, and said first detection means being arranged to cause operation of the first latch means to release the first lid on the decking to enable it to be applied to said tin, a second detection means for detecting the trailing end of the first lid after it has been released from the first latch means, to cause release of the second latch means, a third detection means for detecting when the leading edge of the second lid has passed the first latch means, but before the trailing edge of the second lid has passed the first latch means, for the operation of the first latch means to arrest movement of the second lid in the position previously occupied by the first lid, and a fourth detection means for detecting when the leading edge of the third lid has passed the second latch means but before the trailing end of the third lid has passed the second latch means, to cause actuation of the second latch means to retain the third lid in the position previously occupied by the second lid.

The said first to fourth detectors may be combined so that two or more may comprise the same detector means.

The first and second latch means may each comprise a lever arm swingable on an- axis by means of an air operated cylinder the supply and exhaust of air to which is controlled by solenoid means operated by the said detectors.

The decking may comprise parallel decking rails between which are decking rollers permitting the lids to move down the decking under gravity.

At the end of the decking wherefrom the lids are discharged onto the tins, there may be a retention plate causing the first lid to stop in a position presenting it suitably for take-up by the tin, so that the lids will not simply be ejected from the end of the decking freely under gravity. Such plate may comprise a plastics material plate which locates on the under surface of the lid between the side portions of the rim. This utilisation of a retention plate which simply supports the lid ready to be taken up by a tin in itself constitutes an advance in the state of the art.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a side elevation of lidding apparatus according to the invention; Fig. 2 is a plan view of the apparatus shown in Fig. 1; and Fig. 3 is an enlarged side view showing a detail of the apparatus shown in Fig. 1.

Referring to the drawings, the apparatus as shown clearly in Figs. 1 and 2 comprises essentially conveyor decking 10 inclined downwardly and slightly from the left hand end to the right hand end. The decking is made up essentially of a pair of side plates 12, 14 supported on frame legs 16.

Extending between the plates 12 and 14 are a plurality of rollers 18 arranged in parallel relationship and each rotatable about its axis 20. Each roller comprises a cylindrical central portion 22 which is of mild steel or the like, provided with plastic bushes 24 which are replaceable when worn. The lines 26 and 28 show the lines of travel of the edges of the lids of which two are shown at 30 and 32 in Fig. 2.

Simply, the lids travel on the decking from left to right in Fig. 1 and travel down the decking by gravity by being supported on the bushes 24 of the roller. The movement of the lids down and along the decking is controlled by means of sensing and latching devices to be described hereinafter.

The decking is associated with a feed conveyor 34 which carries baking tins 36 and 38 at spaced intervals indicated by the dimension 40 in Fig. 1, and the decking apparatus operates in that lids such as 32 and 30 are discharged one by one from the decking lower end on to the travelling tins 36 and 38 so that the lids will close the respective tins.

To this end, at the lower end of the decking there is provided a support plate 42 which is located centrally of the decking but it is of narrower width than the distance between the lines 26 and 28. The plate 42 is supported on cross-bars 44 and 46, and suitably may be of plastics material. As shown in Fig. 1, when a lid such as lid 32 reaches the discnarge position, the trailing edge of the lid rim as indicated by numeral 48 is engaged and held by a latch plate 50 whilst at the front end the lid rests upon and is supported by the end of the plate 42, again as shown in Fig.1.The lid 32 therefore takes up, as shown in Fig. 1, a position in which it is at a greater inclination than the inclination of the sloped defined by the rollers 18 so that in fact the leading edge of the rim as indicated by numeral 50 is in fact in a position in which it will be engaged by the leading top edge of the travelling tin 38.

The lid 30 is also held by a latch plate 54 which is of similar construction to plate 50, and is operated by means of a similar mechanism. Such a mechanism is shown in somewhat greater detail in Fig. 3, and it- will be seen that the latch plate 50 or 54 is carried by an arm 56 having a split collar 58 which is secured to a shaft 60 mounted on bearings 62 and 64 (Fig. 2) carried by the side plates 12 and 14. A further arm 66 fast with shaft 60 is coupled by a shackle 68 to the end of a piston rod 70 of an air cylinder 72. The other end of the cylinder 72 is pivotally connected to an arm 74 secured to plate 12, the pivot between arm 74 and cylinder 72 being indicated by reference 76.When the cylinder 72 is pressurised so that its effective length is extended, the latch plate 50 or 54 is moved to the down position so that the lids such as 30 and 32 can pass thereover and are unrestrained thereby, whereas when the cylinder 72 is contracted to the chain dotted line position shown in Fig. 3, the plate 50 is moved to an elevated position in which it can restrain the progress of the lid along the decking by engaging inside of the rear edge 48 of the lid rim.

The sequencing of the feeding of the lids is controlled by three sensors S1, S2 and S3 positioned as indicated diagrammatically only in Fig. 1. Such sensors may be for example photo-electric sensors arranged to control the solenoid valves in turn controlling the flow of pressure air to and from the cylinders 72.

The first sensor S1 is arranged to detect the presence of a tin such as tin 38 in the position shown in Fig. 1 and when such tin is detected, the cylinder 72 controlling the position of plate 50 is moved from the restraining position shown in Fig. 1 to a position in which the lid 32 can advance or be removed from the end of the decking by engagement between the front edge of the tin 38 and the front edge 50 of the lid rim. As the lid is taken away with the tin 38 which is moving in the direction indicated by arrow 78, so the detector S2 eventually detects the passage of the rear edge of the lid 32 past detector S2.

This causes contraction of the cylinder 72 controlling plate 54 which is moved to the unlatched position, and the lid 30 can now travel freely down the decking towards the position previously occupied by a lid 32.

When the leading end of the lid 30 is detected by detector S2, plate 50 is returned to the elevated position in order to restrain movement of the lid 30 so that it takes up the position previously occupied by lid 32.

When a subsequent lid moves towards the position of the lid 30 in Fig. 1, the leading end of the lid is detected by detector S3 which causes plate 54 to be raised so that the progress of such third lid will be retarded ensuring that it takes the position of lid 30 in Fig. 1, completing the sequence of operation.

It will be understood that a simple and effective arrangement for the control of the feeding of the lids is achieved.

Claims (11)

1. Lidding appartus comprising feed decking along which the lids are fed one by one to be married up with tins being conveyed one by one under the decking, wherein there is latch means for holding the first lid on the decking, such latch means being arranged to engage the inside of the lid rim at the trailing end thereof, such latch means being released upon the detection of the arrival of a tin to be lidded whereby release of the latch means permits the first lid on the decking to be released and to be taken up by the tin to close the tin.

2. Lidding apparatus according to claim 1, wherein a second latch means is provided in order to engage the inside of the rim of the second lid at the trailing end thereof, and there is further detection means operable to cause release of the second latch only when release of the first lid in the decking has been detected.

3. Lidding apparatus according to claim 1, 2, wherein the lids are fed from the decking under gravitational forces but again the leading edge of the rim would be located so as to lie in the path of the leading edge of the tin to which it is to be applied so that the tin will assist in taking the first lid away from the decking.

4. Lidding apparatus according to claim 1, 2 or 3, comprising first detection means for detecting the arrival of a tin to be lidded, and said first detection means being arranged to cause operation of the first latch means to release the first lid on the decking to enable it to be applied to said tin, a second detection means for detecting the trailing end of the first lid after it has been released from the first latch means, to cause release of the second latch means, a third detection means for detecting when the leading edge of the second lid has passed the first latch means, but before the trailing edge of the second lid has passed the first latch means, for the operation of the first latch means to arrest movement of the second lid in the position previously occupied by the first lid, and a fourth detection means for detecting when the leading edge of the third lid has passed the second latch means but before the trailing end of the third lid has passed the second latch means, to cause actuation of the second latch means to retain the third lid in the position previously occupied by the second lid.

5. Lidding apparatus according to claim 4, wherein the first and second latch means each comprise a lever arm swingable on an axis by means of an air operated cylinder the supply and exhaust of air to which is controlled by solenoid means operated by the said detectors.

6. Lidding apparatus according to claim 4 or 5, wherein the decking comprises parallel decking rails between which are decking rollers permitting the lids to move down the decking under gravity.

7. Lidding apparatus according to claim 4, 5 or 6, wherein at the end of the decking wherefrom the lids are discharged, there is a retention plate causing the first lid to stop in a position presenting it suitably for take-up by the tin, so that the lids will not simply be ejected from the end of the decking freely under gravity.

8. Lidding apparatus according to Claim 7, wherein the said plate comprises a plastics material plate which locates on the under surface of the lid between the side portions of the rim.

9. Lidding apparatus comprising feed decking along which the lids are fed one by one to be moved up with tins being conveyed one by one under the decking, and at the end of the decking wherefrom the lids are discnarged onto the tins, there is a retention plate causing the first lid to stop in a position presenting it suitably for take-up by the tin, so that the lids will not simply be ejected from the end of the decking freely under gravity.

10. Lidding apparatus according to claim 9, wherein said plate comprises a plastics material plate which locates on the under surface of the lid between the side portions of the rim.

11. Lidding apparatus substantially as heremnbefore described with reference to the accompanying drawings.