GB2154535A - Feeding wrappers to wrapping machines - Google Patents

Abstract

Individual wrappers of flaccid material 18 are gripped along their leading edges in successive gripper units 23 at a wrapper capture station 21 and advanced, by rotation of the gripper units around a vertical rotational axis 42, to a transfer station 14 to be released, and nipped to individual items (11) e.g. sweets to be wrapped, as the items are elevated (16) and transferred from the pockets 12 of a feed conveyor (13) into the pockets of a wrapping wheel (17) which rotates about a horizontal axis. The trailing portions of the wrappers are supported on guides 24 during movement from the capture station to the transfer station. Each wrapper is cut from a web fed vertically into the capture station. <IMAGE>

Description

SPECIFICATION Feeding wrappers to wrapping machine This invention relates in general to the feeding of a succession of wrappers to the wrapping mechanism of a wrapping machine. It is of particular use in the feeding of wrapping material of the type known as flaccid material (of which one example is polypropylene) to high speed wrapping machines.

In the previously proposed machines for wrapping sweets which are fed in succession from a feed disc into separate pockets of a wrapping wheel, sheets of wrapping material are cut from a continuous web and laid, in succession, one over each sweet in a pocket and pinned or pressed (herein "nipped") to the surface of the sweet so as to be moved upwardly with the sweet into a corresponding pocket of the wrapping wheel by a pusher at each operation of the wrapping wheel.

The present inventor has recognised that the operation of the previously proposed wrapping machine relies upon a certain degree of rigidity in the wrapping material, to prevent the wrapper from curling or from getting out of place while being laid over the sweets. This is why the machine is not able to guarantee satisfactory feeding of flaccid wrappers due to their tendency to curl once they had been severed from the web.

An object of the invention is to provide a wrapping machine of the aforementioned type, capable of handling flaccid materials.

According to a first aspect of the present invention there is provided a method of wrapping a succession of like items in a succession of pockets of a wrapping wheel, known per se and including a transfer station at which a pusher transfers one said item from a feed conveyor together with a wrapper for the item to a pocket of the wrapping wheel, the method comprising the steps of: (i) gripping each successive wrapper on at least one grip face of a mobile gripping means at a wrapper capture station; (ii) advancing the gripping means from the capture station to the transfer station thereby carrying the captured wrapper to the transfer station; (iii) releasing the captured wrapper from the gripping means when the wrapper is nipped to the item which is to be wrapped within it.

In a second aspect, the invention provides apparatus to carry the method into effect.

Preferably, the gripping means comprises a plurality of like bifurcated gripper units, between the opposed grip faces of each of which units one said wrapper is gripped, carried from the capture to the transfer station and then released by movement apart of the grip faces, such movement together and apart of the grip faces being conveniently cam controlled. The gripper units are conveniently arranged at equal intervals around the periphery of a circle at the centre of which are the appropriate camming and cammed surfaces.

Other gripping means, such as pneumatic pads, can be provided if more appropriate than the bifurcated units.

Preferably, the wrapper is gripped along an edge thereof, which edge is a leading edge in the movement of the wrapper from the capture station to the transfer station. Pulling the flaccid wrapper along the full length of its leading edge affords the best chance of avoiding any curling, creasing or folding of the wrapper during movement to the transfer station.

It will be appreciated that the invention provides that control of the flaccid wrapping material is maintained from the moment of severance of individual wrappers from the web until the time the wrapper is taken, together with the item to be wrapped, into the wrapping elements of the machine.

One embodiment of the invention is illustrated in the accompanying drawings in which: Figure I is a plan view of part of a sweet wrapping machine, and Figure 2 is an elevation, drawn partly in section, viewed in the direction of the arrow A in Fig. 1.

In the drawings, sweets 11 (Fig. 2) are contained in separate pockets 12 of a continuously rotating feed disc 13, and are conveyed in succession to a transfer station 14 where they are removed in succession from the pockets 12 by a reciprocating pusher 16 which feeds each sweet upwardly into a pocket of an intermittently rotatable wrapping wheel 17.

Prior to the upward movement of the pusher 16, a wrapper 18 is severed (Fig. 2) from a web 19 of flaccid wrapping material by knives 20 at a wrapper cut and capture station 21 (Fig. 1) and subsequently, at the transfer station 14, laid over and nipped to the sweet in the pocket so as to be moved upwardly with the sweet by the pusher 16.

Substantially at the same time as the pusher is about to contact the sweet, a wrapper nipping member 22 is caused to move into gently pressing contact with the wrapper 18 so as to nip it against the upper surface of the sweet. The pusher, sweet, wrapper and nipping member then move upwardly together to position the sweet and wrapper in the pocket of the wrapping wheel 17.

As each wrapper 18 is severed from the web 19, it is seized along one edge at the capture station 21 between the opposed grip faces of one of a series of gripper units, generally indicated by the reference numeral 23, and of which five units, 23A-E, are shown in the drawings. It is then moved to the transfer station 14, with the gripped edge leading, where it is released by the gripper unit 23 and, as mentioned above, nipped to the upper surface of the sweet 11 by the member 22. The trailing length of the wrapper 18 behind the gripped leading edge is supported on guides 24 during its movement from the wrapper capture station 21 to the transfer station 14.

Each gripper unit assembly 23 consists of a fixed portion 25 secured to a disc 26, at regular intervals with the other fixed portions 25 around the periphery of the disc 26. A movable portion 27 is pivotally mounted at a pivotal axis 30 on the fixed portion 25. It has an extension 28 carrying a roller 29 urged by a spring 31 into engagement with the surface of a normally stationary cam 32. The disc 26 is secured to a driving sleeve 33 (Fig. 2), rotatably mounted in bearings 34 housed in the framework 36 of the machine, and is intermittently rotated by a well known type of indexing mechanism comprising a cam 37 which engages, in succession, a series of rollers 38 rotatably mounted on a driving hub 39 to the sleeve 33.

The cam 32 for opening and closing the faces of the gripper unit 23 is secured to a hub 41 itself secured to a spindle 42 mounted for rotation in the sleeve 33. The periphery of the cam 32 is so profiled as to maintain the faces of the gripper units 23 for the most part in a closed disposition. As each gripper unit, for example unit 23E, approaches the wrapper capture station 21, however, its roller 29 engages (Fig. 1) a lobe 43 on the cam 32 which opens the faces of the gripper unit 23E at this station. As the wrapper 18 is severed from the web 19, the cam 32 is oscillated by the spindle 42 so that the roller 29 moves off the lobe 43 on to the low point of the cam 32 to close the gripper faces and thus seize and capture the wrapper 18.

During such oscillation of the cam 32, a further lobe 44 on the cam 32 engages the roller 29 of a gripper unit 23C which is at that time positioned at the transfer station 14, such action opening the faces of this gripper unit 23C to release its wrapper 18. As this gripper unit 23C commences its movement away from the transfer station 14, the roller 29 then moves on to the low point of the cam 32 to close the grip faces of the unit 23C. The spindle 42 is oscillated by a cam-operated link 46 attached to an arm 47 itself secured to the spindle 42.

It will thus be seen from the above description that in the illustrated embodiment control of the wrapper 18 is maintained from the moment of severance from the web 19 until the time it is received together with the sweet 11 into the wrapping wheel 17. Depending on the specific design of other embodiments, the guides 24 may be dispensed with. Further, alternative camming arrangements can be made which would avoid the need to have one gripper unit at the transfer station 14 simultaneously with another gripper unit at the capture station 21. The use of oscillation in the operation of the cam 32 provides a faster opening and shutting of the grip faces then could reasonably be provided with a cam which does not move counter to the advance of the gripping means at the moments when movement of the grip faces is required.

It will be appreciated by those skilled in the art that in the illustrated embodiment a vertical wrapper feed is utilised i.e. the wrapper material moves from its vertical disposition at the wrapper capture station to a horizontal disposition for advancement to the transfer station. Vertical wrapper feed is considered to be highly advantageous when using flaccid materials, and its incorporation in the illustrated apparatus to be a further aspect of the present invention.

Claims (15)

1. A method of wrapping a succession of like items in a succession of pockets of a wrapping wheel, known per se and including a transfer station at which a pusher transfers one said item from a feed conveyor together with a wrapper for the item to a pocket of the wrapping wheel, the method comprising the steps of: (i) gripping each successive wrapper on at least one grip face of a mobile gripping means at a wrapper capture station; (ii) advancing the gripping means from the capture station to the transfer station thereby carrying the captured wrapper to the transfer station; and (iii) releasing the captured wrapper from the gripping means when the wrapper is nipped to the item which is to be wrapped within it.

2. A method according to claim 1, wherein the wrapper is gripped along the length of a leading edge thereof.

3. A method according to claim 2, wherein the transfer station is horizontally adjacent to the capture station and wherein the length of the wrapper which trails behind the gripped leading edge as the wrapper is advanced from the capture station to the transfer station is supported on guides.

4. A method according to any of the preceding claims including the step of cutting the wrapper from a web fed vertically into the wrapper capture station.

5. A method substantially as hereinbefore described with reference to the accompanying drawings.

6. Apparatus for feeding a succession of wrappers to a transfer station of wrapping apparatus, where a succession of like items is transferred in succession by a pusher from a feed conveyor to one of a succession of pockets in a wrapping wheel, the apparatus comprising: means to grip each successive wrapper on at least one grip face of a mobile gripping means at a wrapper capture station; means to advance the gripping means from the capture station to the transfer station thereby carrying the captured wrapper to the transfer station; and timing means to release the captured wrapper from the gripping means as the wrapper is nipped to the item which is to be wrapped within it.

7. Apparatus as claimed in claim 6, wherein the gripping means comprises a plurality of gripper units spaced at equal intervals around a rotational axis.

8. Apparatus as claimed in claim 8, wherein the gripper units are bifurcated and comprise a fixed gripper face and a movable gripper face which moves relative to the fixed face to grip and release a wrapper between the gripper faces.

9. Apparatus as claimed in claim 8, wherein the movable gripper face follows a cam track which extends around the said rotational axis.

10. Apparatus as claimed in claim 9 including means to drive the cam defining the track intermittently against the direction of advance of the grip per units, and then in the advancing direction, in order to secure a more rapid opening and closing of the grip faces.

11. Apparatus as claimed in any one of claims 6 to 10 including means to time the feed of each wrapper to the capture station such that the gripping means grips the wrapper along a leading edge thereof.

12. Apparatus as claimed in any one of claims 6 to 11, wherein the said rotational axis is vertical when the apparatus is in use and means are provided for feeding the wrappers to the capture station in a vertical direction.

13. Apparatus as claimed in claim 12 as dependent on claim 11 including guides to support the length of the wrapper trailing behind its gripped leading edge as it advances from the capture station to the transfer station.

14. Apparatus as claimed in any one of claims 6 to 13 including means to sever individual wrapper lengths in succession at the wrapper capture sta action from a web of wrapping material.

15. Apparatus for feeding wrappers substantially as hereinbefore described with reference to, iand as shown in, the accompanying drawings.