GB2062808A - A glueing roller for a labelling machine - Google Patents

Abstract

A glueing roller comprises a rigid support sleeve 17 mounted for rotation on a shaft 14 and a rigid, wear-resistant roller casing 20 fixed thereon by means of axially spaced, radially resilient support elements 19. The support elements comprise flat, resilient members of elastomeric material with a hardness of 20-30 shore. The thickness of the rotational unit formed by the support sleeve, support members and roller casing has a ratio of 1:5 to 1:50 with respect to the diameter of the roller. <IMAGE>

Description

SPECIFICATION A glueing roller for a labelling machine The invention relates to a glueing roller of the kind comprising a rigid support sleeve mounted to rotate on a shaft and a rigid roller casing located thereon by means of radially resilient support members distributed in the axial direction. A glueing roller of this kind is intended to be used in a labelling machine, in which the thickness of the layer of glue applied to the roller casing can be controlled by a scraper member, in particular a doctor blade, and a glueing pallet rolls on the roller casing by its pick-up surface for the labels.

In order that a layer of glue which is as uniform as possible is transferred from the glueing roller to the pick-up surface at the time of the rolling movement, it is necessary that the distance between the roller casing and the pick-up surface is maintained with an accuracy of 2-5/100 mm.

This accuracy is not achieved if, owing to a disturbance in the labelling machine, the glueing pallet still carries one or more labels, when it is to receive a new application of glue. The thickness of a label amounts to approximately 5/100 mm. In order that the glueing roller is able to tolerate change in the spacing, a hard rubber roller was used hitherto as the roller. However, hard rubber rollers have the drawback that they are relatively sensitive to friction.

In a glueing roller of the aforesaid kind, such a drawback exists if labels, which are not removed by the gripper cylinder, reach the glueing roller, stick to the latter singly or in higher numbers and are conveyed as far as the doctor blade during rotation of the glueing roller. The labels accumulate at this point and produce friction grooves on the surface of the glueing roller and may even destroy the roller itself.

In the case of a glueing roller of the aforementioned kind, the resilient support members are constructed as coil springs with a varying diameter of the individual coils, so that the coils of small diameter are seated on the support sleeve and their outer coils support the roller casing. In this glueing roller, the radial resilience of the roller casing is very great. Using the coil springs as support members, the roller casing cannot be arranged coaxially on the shaft with the desired accuracy. When using the known roller, such accuracy cannot be obtained, because during the rolling operation of the glueing pallet on the glueing roller, considerable variations in the distance have to be equalised. Discs bearing against the end faces close off the annular gap between the support sleeve and the roller casing.

Since glue enters this region under normal operation, there is a danger that after a relatively long operating stoppage, these discs stick to the roller casing, so that the necessary resilience no longer exists (US PS 2 638 073).

An object of the invention is to provide a glueing roller of the aforementioned kind, whereof the roller casing can be adjusted with an accuracy of several hundred millimetres with respect to a glue doctor and a pick-up member for labels rolling thereon, but which also overcomes changes in the distance between the pick-up surface and surface of the casing due to labels which have not been picked up, without damage.

This object is achieved according to the invention due to the fact that the support members are flat resilient rubber members with a hardness of 20-30 shore, in which case the total thickness of the common rotary unit composed of support sleeve, support members and roller casing has a ratio of 1:5 to 1:50 with respect to the diameter of the roller.

The glueing roller according to the invention can be produced and operated with the accuracy of a glueing roller consisting solely of rigid components, since with the selected ratios of dimensions of diameter and material thickness, the relatively flat, resilient rubber members centre the roller casing exactly and keep it centred.

However, the elasticity of the members is sufficient to yield slightly in the case of pressure caused by labels which have not been removed.

There is thus no need for a resilient rubber outer skin with the drawback that a doctor blade produces grooves thereon, if labels accumulate in front of the latter. The roller casing may consist of steel.

Preferably, the resilient rubber members close off the annular space formed by the support sleeve and the roller casing, at its end faces. Thus, discs closing off the annular space are not required. This means that the roller casing is not able to stick to inner rigid parts. It thus remains resilient on the support sleeve, even after a long operating time.

The resilient rubber members are preferably rings spaced apart from each other.

The invention will now be further described by way of example with reference to the drawings, in which: Fig. 1 shows one embodiment of labelling machine diagrammatically in plan view, and Fig. 2 is an axial section through one embodiment of glueing roller according to the invention.

The illustrated labelling machine comprises a rotary table 1 adapted to rotate uniformly in the direction of arrow P 1, on which are three identical glueing pallets 2, 3, 4, each mounted to rotate about an axis disposed between its cylindrical curved pick-up surface 5 and the centre of curvature of said surface. The pallets 2, 3, 4 are driven by respective pinions 6 which mesh with a stationary toothed annulus 7 and run therearound upon rotation of the table 1.Due to an interposed irregular transmission controlled by way of a stationary cam, the rotation of the removal members or glueing pallets can be controlled as regards speed so that their pick-up surfaces 5 roll against th evarious stations of the labelling machine, more particularly the flat front side of a stationary pile of labels 8, the curved surface of a gripper cylinder 9 rotating in the direction of arrow P3 and the curved surface of a glueing roller 10 rotating in the direction of arrow P4 and which has a smaller diameter. A suitable irregular transmission is described in German OS 2 325 244.

The method of operation of a labelling machine of this kind is as follows: during the rotation of the table 1, the pick-up surface 5 of each glueing pallet 2, 3, 4 rolls on the glueing roller 10, which is supplied with glue by an applicator member 21. A stationary doctor blade 11 controls the thickness of the layer of glue applied. As the pick-up surface 5 rolls on the glueing roller 10, a layer of glue adheres to the pick-up surface 5. The pallet prepared in this way then rolls on the front side of the pile of labels 8, due to which the front label sticks to the pick-up surface on account of the glue. This label is then conveyed to the gripper cylinder 9, which removes it from the pick-up surface 5 and transfers it to bottles 1 2 conveyed past it on an arcuate path. The labelling machine described so far is known (German OS 2 325 244).

The glueing roller comprises a hollow shaft 13 which is prevented from rotating, through which a drive shaft 14 passes, which is driven by way of gears by the table 1. Mounted to rotate on the hollow shaft 13 by means of bearings 1 5, 16 is a cylindrical support sleeve 1 7, which is fixed to the drive shaft 14 for rotation therewith by a plate 18.

At its outer side, the support sleeve 17 supports a plurality of support members 1 9 constructed as rings of resilient elastomeric material e.g. rubber spaced axially from each other, which in turn support a rigid cylindrical roller casing 20 of steel sheet, hard synthetic material, or other wearresistant material. The resilient material of the support members 9 has a hardness of approximately 20-30 shore. With a typical outer diameter of the roller of 100 to 200 mm, the thickness of the wall of the roller casing 20 is approximately 6 mm, of the annular support members 9 approximately 6 mm, and of the support sleeve 17 approximately 10 mm.The ratio of the length (the axial dimension) of the support members 1 9 to the corresponding dimension of the spaces between adjacent support members is approximately 1-2:1.

The roller casing 20 in conjunction with the support members 19 supporting it and the support sleeve 1 7 located in the immediate vicinity gives the glueing roller resilience in the radial direction, with the greatest accuracy, without radial stress and ensures the desired high resistance to wear as regards friction. If, owing to a disturbance, labels should accumulate on the glued pick-up surface 5 of the glueing pallets 2 to 4 or from the glueing roller 10 up to the doctor blade 1 which is constructed in two parts in the embodiment of Figure 2 for labels applied to the body and neck of the bottle, then the roller is damaged neither by excessive pressure in the region of the glueing pallet 2 nor due to heat as a result of friction or abrasion.

Claims (4)

1. A glueiny roller comprising a rigid support sleeve mounted for rotation on a shaft and a rigid, wear-resistant roller casing fixed thereon by means of axially spaced, radially resilient support elements comprising flat, resilient members of elastomeric material with a hardness of 20-30 shore, the thickness of the rotational unit formed by the support sleeve, support members and roller casing having a ratio of 1:5 to 1:50 with respect to the diameter of the roller.

2. A roller as claimed in claim 1, wherein the resilient rubber members close off the ends of the annular space between the support sleeve and the roller casing.

3. A roller as claimed in claim 1 or 2, wherein the resilient rubber members are axially spaced rings.

4. A glueing roller, substantially as herein described with reference to and as illustrated in the accompanying drawings.