GB2226295A

GB2226295A - Wrapper transport control in a wrapping machine

Info

Publication number: GB2226295A
Application number: GB8928723A
Authority: GB
Inventors: Werner Kmoch; Juergen Koerner; Gerhard Heinrich; Michael Aurin
Original assignee: Nagema VEB
Current assignee: Nagema VEB
Priority date: 1988-12-20
Filing date: 1989-12-20
Publication date: 1990-06-27
Anticipated expiration: 2009-12-20
Also published as: GB8928723D0; DE3936869C2; IT8948653A0; DE3936869A1; IT1237248B; DD278315A1; BR8906738A; GB2226295B; JPH02242717A; IT8948653A1

Description

1 - 1 WRAPPER TRANSPORT CONTROL IN A WRAPPING MACHINE The present

invention relates to a wrapping machine and has particular reference to control of wrapper transport in dependence on a feed of articles to be wrapped, for example on the degree of filling of retaining elements of transport means of the machine.

Control means for that purpose are known for continuously operating machines from DD-PS 138 635, DD-PS 158 536 and DD-PS 252 354. In these control systems, arranged beside a wrapping wheel is a scanning control wheel which rotates at the same circumferential speed and which has scanning levers mounted to be radially pivotable at the circumference. Positional change of the levers in dependence on the degree of filling of the retaining elements of the wrapping wheel is transmitted by way of a pawl mechanism and a lever arm with a cam segment to a feed roller for the wrappers. It is thereby possible, through raising of the feed roller, to interrupt'the wrapper transport for an operating cycle in which no article to be wrapped is situated between the retaining elements of the wrapping wheel.

It is disadvantageous in these systems that the articles to be wrapped are exposed to an additional mechanical impact stressing through sensors or scanning levers. Moreover, the complicated pawl mechanism is subject to high stress and thereby a high wear and the adjustment of the scanning levers is difficult.

A further such control system is illustrated in DD-PS 256 108. In this case, retaining elements of withdrawal wheels serve as a scanning device, wherein positional change of the retaining elements is transmitted by way of a pawl mechanism to a cam segment for the raising of a feed roller for the wrappers. The articles to be wrapped are not subjected to any additional mechanical stressing in this system. The pawl mechanism is substantially simplified by comparison with the previously described systems, but due to the very short switching times in the high performance range is also subject to a high wear. Moreover, apart from the spatial association of the withdrawal wheel, scanning device and wrapper take-off, dynamically optimum lifting-off movements of the feed roller are not provided by transmission of the scanning result to a cam segment.

It would thus be desirable to reduce the wear of control systems of that kind. Preferably, also, the adjusting operation should be facilitated and lifting-off movement of a feed roller should be improved, so as to increase the reliability at machines in the high output range. For preference, the scanning result should be translatable, without complicated paw] mechanism, into a control of the wrapper transport.

According to the present invention there is provided a wrapping machine provided with control means for control of wrapper transport in dependence on a feed of articles to be wrapped, the control means comprising lever means Divotable to interrupt wrapper transport in the machine, two cams drivable to rotate at half a given operating rotational speed of the machine, two cam follower members each provided with an abutment surface and each oscillatable, in opposite phase to the respective other member, by a respective one of the cams between two end settings in which the abutment surface of that member is spaced from an associated contact surface portion of the lever means, and means responsive to such feed to dispose a respective shim between the abutment surface of a selected member and the associated contact surface portions to cause pivoting of the lever means by that member.

Preferably, two cams of substantially equal cam track course are mounted, displaced through 180' relative to each other, on a shaft in the region of a wrapper take-off, the shaft having a speed ratio of 1:2 relative to the machine speed. The cam follower members, for example levers provided with cam follower rollers, have abutment surfaces which stand opposite to and at a spacing from the contact surface portions of the lever means, for example a pivotably mounted lifting-off lever. Displacing devices with the shims can be arranged at both sides of the lifting-off lever. The minimum spacing between the abutment surfaces and the contact surface portions of the lifting-off lever is preferably smaller than the thickness of the shims. For preference, the displacing devices are mounted on the lifting-off lever.

In the case of a wrapping machine embodying the invention, it may thus be possible to achieve optimum lifting-off movement of a transport roller for wrappers and to rationalise the adjustment operation as well as reduce wear.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawing, which is a schematic perspective view of control means in a wrapping machine embodying the invention.

Referring now to the drawing, there is shown control means arranged in the region of a wrapper take-off of a sweet wrapping machine. The control means comprises a housing 1, in which two cams 2 and 3 are fastened on a shaft 4 which rotates at half the operating rotational speed of the machine in performance of wrapping cycles. The cams 2 and 3, the cam tracks of which are constructed alike, are displaced through 180' relative to each other. The cam 3 stands in effective connection under spring bias with a cam roller lever 5 and the cam 2 with a cam roller lever 6. The levers 5 and 6 are mounted to be pivotable on an axle 7. Abutment surfaces 8 and 9 are provided at the free ends of the levers 5 and 6 respectively, wherein the abutment surface 8 is disposed opposite a contact surface 10 and the abutment surface 9 opposite a contact surface 11 of a lifting-.off lever 12, the abutment surfaces being disposed at a spacing A from the control surfaces. The lever 12 is mounted to be pivotable at the housing 1 and is connected with a transport roller 13, which rests under spring bias on a transport roller 14.

Mounted at both sides of the lever 12 are setting members 15 and 16 with shims 17 and 18, which are arranged to be displaceable in direction towards the abtuemnt surfaces 8 and 9 of the levers 5 and 6 and are movable into and out of a position between the abutment surfaces 8 and 9 and the contact surfaces 10 and 11. Actuation of the setting members 15 and 16 is by way of a mechanical or electrical control (not shown) in dependence on the degree of filling of sweet retaining element pairs of a transport device of the machine.

In use, the shaft 4 and thereby the cams 2 and 3 rotate at half the rotational speed of the rotational speed of the sweet wrapping machine.

In that case, each cam 2 and 3 is associated in alternation w ith a working cycle or retaining element pair of the transport device. On following of the cam tracks of the cams 2 and 3 by the cam roller levers 5 and 6, these are set into pivotal oscillation in opposite phase. In that case, the abutment surfaces 8 and 9 approach:and move away from, in alternation and within a variable spacing A, the contact surfaces 10 and 11. The minimum spacing A between the abutment surfaces 8 and 9 and the contact surfaces 10 and 11 is smaller than the thickness 1.

of the shims 17 and 18 of the setting members 15 and 16 and the maximum spacing A between the abutment surfaces and the contact surfaces is slightly greater than the thickness of the shims. If sweets are situated between all retaining element pairs of the transport device, the two setting members 15 and 16 remain unactuated and the controllable shims 17 and 18 remain outside the range of the abutment surfaces 8 and 9 and the contact surfaces 10 and 11. If scanning of a retaining element pair indicates that a sweet is missing, then by way of the setting member associated with this retaining element pair, for example the setting member 15, the shim 17 is pivoted into the range of the associated abutment surface 8 and contact surface 10.

The pivoting in of theshim 17 takes place at the instant at which the spacing A has reached the maximum size. On pivotation of lever 5 and thereby of the abutment surface 8 in direction towards the contact surface 10, the lever 12 is pivoted by way of the shim 17 and the transport roller 13 is raised so as to interrupt the wrapper transport for this working cycle. Further such courses of action can take place by way of the setting members 15 and 16 associated alternately with the respective retaining element pairs, wherein the actuating connection between retaining element pairs and the setting members 15 and 17 can be, for example, mechanical or electrical 1

Claims

CLAIMS 1. A wrapping machine provided with control means for control of

wrapper transport in dependence on a feed of articles to be wrapped, the control means comprising lever means pivotable to interrupt wrapper transport in the machine, two cams drivable to rotate at half a given operating rotational speed of the machine, two cam follower members each provided with an abutment surface and each oscillatable, in opposite phase to the respective other member, by a respective 6ne of the cams between two end settings in which the abutment surface of that member is spaced from an associated contact surface portion of the lever means, and means responsive to such feed to dispose a respective shim between the abutment surface of a selected member and the associated contact surface portions to cause pivoting of the lever means by that member.
2. A machine as claimed in claim 1, the cam follower members each comprising a lever carrying a cam follower roller.
3. A machine as claimed in either claim 1 or claim 2, wherein the cams are mounted on a shaft disposed in the region of a wrapper takeoff of the machine, the cams defining substantially the same cam tracks but being displaced 180' relative to each other about the shaft.
4. A machine as claimed in any one of the preceding claims, wherein the minimum spacing of each abutment surface from the associated contact surface portion is less than the thickness of the respective shim.
5. A machine as claimed in any one of the preceding claims, said means responsive to the-feed comprising two displacing devices to each displace a respective one of the shims.
6. A machine as claimed in claim 5, wherein the displacing devices are mounted on the lever means.
7. A wrapping machine substantially as hereinbefore described with reference to the accompanying drawing.

Published 1990 at The Patent Office. State House.66 7lHi9IHc%oorn LcrJor. WClF 47P Further copies niky be obtanedfrori The Pat.ento.,.:ce Sales Branch. St Ma-y Cray- Orpington Kent BR5 3RE; Printed by Lechnio-es ltd. St Ma-y Crky. Ken. Cen 1 87