GB1587241A - Tube-end turnover device - Google Patents

Description

(54) IMPROVED TUBE-END TURNOVER DEVICE (71) We, IMPERIAL CHEMICAL INDUS TRIES LIMITED, Imperial Chemical House, Millbank, London SWIP 3JF a British Company do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method of forming a roll turnover on the end of a cylindrical tube such as a cardboard tube and to a device for carrying out the said method. In particular the invention is advantageous for turning over the end of a tubular container to provide an abutment to retain an end disc or cap in the container.

The operation of turning over the end portions of tubular containers, especially cardboard containers, is common practice in the packaging trade and is variously described as turning over, doming, curling or end-rolling.

This operation is normally performed by a rotating tool comprising a thick plate having an annular groove in a flat surface. The groove is shaped in cross-section to the crosssectional profile of the desired turnover and, for an inside turnover as normally required in a tubular container, the outside and inside diameters of the groove correspond to the outside and inside diameters respectively of the turned over end portion of the tube. To form the turnover a square cut end of the tube is engaged in the groove and the tool and the tube are axially pressed together whilst the tool is rotated relatively to the tube around the central axis of the groove and the tube.

With a plain annular groove, it is commonly found that the pressure required for satis factory turnover causes the wall of the tube to collapse. It has, therefore, become common practice to insert 2 thin circular rod radially across the groove of the tool so that less than half of the rod thickness stands above the bottom of the groove. This rod provides a point of deformation which re sults in progressive deformation around the tube end and substantially reduces damage of the tube wall.

The aforedescribed turnover tool is, how ever, very difficult to make to the accuracy required and the groove requires laborious polishing. The deforming rod is difficult to position accurately and it impairs the symmetry of the turnover. Further the groove must fit reasonably tightly over the turned over end with the result that friction between the tool and the tube is high and lubrication is often necessary for large tubes.

Turnover forming devices incorporating a plurality of appropriately contoured rollers mounted on radius arms for rotation around the tube end have also been proposed but these are also expensive to construct and maintain.

We have now devised an improved method of turning over a cylindrical tube end and providing a simply constructed tube turnover forming device wherein the disadvantages of the previous devices are substantially ameliorated.

In accordance with this invention a method of forming a roll turnover on a cylindrical tube end comprises locating a former over a portion of the tube end wall, said former comprising a rigid rod having a transverse groove in which the said portion of the tube end wall is engaged, said groove having a transverse profile corresponding to the desired transverse profile of the turned over end, and moving said rod around the tube end wall whilst simultaneously biassing said rod against said end wall whereby the tube end is turned over.

Preferably the rigid rod is circular in crosssection and has a circumferential groove in which the tube end wall is engaged.

The invention also includes a forming device for forming a roll turnover on a cylindrical tube end, which device comprises at least one rigid rod having a transverse turnover groove of smooth rounded bottom profile in which the rim of the tube at the tube end is engaged and drive means whereby said rod may be biassed against and rotated around the tube end so that the tube end follows the contour of the said groove and turns over.

The device of the invention presents much less friction generating surface to the tube end than the rigid devices hitherto used and, therefore, the torque and power required to produce a turnover is substantially reduced. Moreover the groove can be formed much more accurately and cheaply than the annular groove in previous devices.

In a preferred form the drive means of the forming device comprises a central rotatable drive element from which the grooved rod extends radially.

The rod or rods are each preferably circular in cross-section and formed with a circumferential groove wherein the tube end is engaged and turned over. Conveniently the circular rods may each be located in a transverse bore in the drive element and in this form a single rod may advantageously extend through the drive element and be formed at each end with a groove adjacent to the end, which grooves in operation simultaneously engage the tube end at diametrically opposed positions. The circular rod is preferably an gularly adjustable in the bore of the drive element by rotation around its longitudinal axis and advantageously the device includes locking means whereby the rod may be locked in the bore at any desired angle of rotation. This feature enables the rod to be readily adjusted to present a fresh turnover groove profile when the profile at any position becomes deformed and unserviceable through wear in use. Convenient locking means comprise a set screw in screw-en gagement with the drive element and in frictional engagement with the rod.

Preferably the device comprises a central boss mounted on the drive element, which boss is formed as a clearance fit in the turned over tube and is adapted to enter the tube end as the tube rim is engaged in the groove.

The boss prevents the deformed portion of the tube end springing back before it is fully turned over and assists the location of the tube end in the groove. The boss may conveniently be formed as an integral part of the drive element or as a separate member attached to the drive element. In one preferred construction the boss is sleeved on a drive shaft and located thereon by the grooved rigid rod extending through coincident bores in the boss and the drive shaft.

The rod is conveniently made of metal, for example, steel, but it will be apparent that it could be constructed from other rigid constructional material.

The invention is further illustrated by the embodiment which is hereinafter particularly described, by way of example, with reference to the accompanying drawings wherein Figure 1 shows in perspective a tube turnover device of the invention.

Figure 2 shows in medial sectional elevation a tube end in engagement with a turnover device.

The device comprises a rod 10, a drive element 11 and a boss 12. The boss 12 is sleeved on the end of the drive element 11 and the rod 10 is located as a sliding fit in a transverse bore in the drive element 11 and a coincident transverse bore in the boss 12, thereby securing the boss in position on the drive element. The rod 10 has two circumferential grooves 13 and 14 located one at each end and is located so that the grooves 13 and 14 are equidistant from the central axis of the drive element 11. In order to facilitate accurate positioning of the rod 10, a circumferential groove 15 is formed in the rod between the grooves 13 and 14 and a locating and locking screw 16, screwed into a threaded bore in the drive element 11, extends into the groove 15 and firmly engages the rod.

Although the locking screw 16 need not necessarily be at the axis of the drive element 11 it is obviously advantageous that it should be, in order to minimise any stresses to which it may be subjected. The drive element 11 has an externally threaded portion 17 by which it may be attached to a drive shaft. The boss 12 has a tapered end portion 18 which acts as a guide to facilitate location of a tube in the grooves 13 and 14.

As shown in Figure 2, in operation the end of a tube 19 is pressed into the grooves 13 and 14 and the drive element 11 is rotated around its axis whilst the tube 19 is restrained against rotation. The end of the tube 19 progressively follows the cross-sectional profile of the bottom of the grooves 13 and 14 and is finally turned over into the position shown in Figure 2. During the turning operation the cylindrical wall 20 of the boss 12 acts as a guide for the turning tube end portion and prevents it springing back from its turned over position.

When both ends of a tubular container are required to be turned over it will be convenient to turn both ends simultaneously by means of two contra-rotating devices of the invention.

It will be evident that the grooves 13 and 14 each engage tube ends at only one position.

There is therefore little total friction between the rotating device and the tube end. Nevertheless, there is considerable friction at the engagement positions and the grooves become worn at these positions. When excessive wear occurs the rod is readily rotated to a new position by unscrewing the screw 16 to release the rod, rotating the rod to a fresh angular position and re-tightening the screw. Thus the life of the rod will be prolonged and will greatly exceed the life of the turnover tools used hitherto. When replacement of the rod 10 is eventually necessary the rod can quickly be disconnected from the device and a new one fitted at the production site without any special fitting tools.

WHAT WE CLAIM IS: 1. A method of forming a roll turnover on a cylindrical tube end comprising locating a former over a portion of the tube end wall, said former comprising a rigid rod having a transverse groove in which the said portion of the tube end wall is engaged, said groove having a transverse profile corresponding to the de sired transverse profile of the turned over end, and moving said rod around the tube end wall whilst simultaneously biassing said rod against said end wall whereby the tube end is turned

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (14)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   forming device comprises a central rotatable drive element from which the grooved rod extends radially.

   The rod or rods are each preferably circular in cross-section and formed with a circumferential groove wherein the tube end is engaged and turned over. Conveniently the circular rods may each be located in a transverse bore in the drive element and in this form a single rod may advantageously extend through the drive element and be formed at each end with a groove adjacent to the end, which grooves in operation simultaneously engage the tube end at diametrically opposed positions. The circular rod is preferably an gularly adjustable in the bore of the drive element by rotation around its longitudinal axis and advantageously the device includes locking means whereby the rod may be locked in the bore at any desired angle of rotation. This feature enables the rod to be readily adjusted to present a fresh turnover groove profile when the profile at any position becomes deformed and unserviceable through wear in use. Convenient locking means comprise a set screw in screw-en gagement with the drive element and in frictional engagement with the rod.

   Preferably the device comprises a central boss mounted on the drive element, which boss is formed as a clearance fit in the turned over tube and is adapted to enter the tube end as the tube rim is engaged in the groove.

   The boss prevents the deformed portion of the tube end springing back before it is fully turned over and assists the location of the tube end in the groove. The boss may conveniently be formed as an integral part of the drive element or as a separate member attached to the drive element. In one preferred construction the boss is sleeved on a drive shaft and located thereon by the grooved rigid rod extending through coincident bores in the boss and the drive shaft.

   The rod is conveniently made of metal, for example, steel, but it will be apparent that it could be constructed from other rigid constructional material.

   The invention is further illustrated by the embodiment which is hereinafter particularly described, by way of example, with reference to the accompanying drawings wherein Figure 1 shows in perspective a tube turnover device of the invention.

   Figure 2 shows in medial sectional elevation a tube end in engagement with a turnover device.

   The device comprises a rod 10, a drive element 11 and a boss 12. The boss 12 is sleeved on the end of the drive element 11 and the rod 10 is located as a sliding fit in a transverse bore in the drive element 11 and a coincident transverse bore in the boss 12, thereby securing the boss in position on the drive element. The rod 10 has two circumferential grooves 13 and 14 located one at each end and is located so that the grooves 13 and 14 are equidistant from the central axis of the drive element 11. In order to facilitate accurate positioning of the rod 10, a circumferential groove 15 is formed in the rod between the grooves 13 and 14 and a locating and locking screw 16, screwed into a threaded bore in the drive element 11, extends into the groove 15 and firmly engages the rod.

   Although the locking screw 16 need not necessarily be at the axis of the drive element 11 it is obviously advantageous that it should be, in order to minimise any stresses to which it may be subjected. The drive element 11 has an externally threaded portion 17 by which it may be attached to a drive shaft. The boss 12 has a tapered end portion 18 which acts as a guide to facilitate location of a tube in the grooves 13 and 14.

   As shown in Figure 2, in operation the end of a tube 19 is pressed into the grooves 13 and 14 and the drive element 11 is rotated around its axis whilst the tube 19 is restrained against rotation. The end of the tube 19 progressively follows the cross-sectional profile of the bottom of the grooves 13 and 14 and is finally turned over into the position shown in Figure 2. During the turning operation the cylindrical wall 20 of the boss 12 acts as a guide for the turning tube end portion and prevents it springing back from its turned over position.

   When both ends of a tubular container are required to be turned over it will be convenient to turn both ends simultaneously by means of two contra-rotating devices of the invention.

   It will be evident that the grooves 13 and 14 each engage tube ends at only one position.

   There is therefore little total friction between the rotating device and the tube end. Nevertheless, there is considerable friction at the engagement positions and the grooves become worn at these positions. When excessive wear occurs the rod is readily rotated to a new position by unscrewing the screw 16 to release the rod, rotating the rod to a fresh angular position and re-tightening the screw. Thus the life of the rod will be prolonged and will greatly exceed the life of the turnover tools used hitherto. When replacement of the rod

   10 is eventually necessary the rod can quickly be disconnected from the device and a new one fitted at the production site without any special fitting tools.

   WHAT WE CLAIM IS: 1. A method of forming a roll turnover on a cylindrical tube end comprising locating a former over a portion of the tube end wall, said former comprising a rigid rod having a transverse groove in which the said portion of the tube end wall is engaged, said groove having a transverse profile corresponding to the de sired transverse profile of the turned over end, and moving said rod around the tube end wall whilst simultaneously biassing said rod against said end wall whereby the tube end is turned

   over.
2. 2. A method as claimed in Claim 1 wherein the rigid rod is circular in cross-section and has a circumferential groove in which the tube end wall is engaged.
3. 3. A method of forming a roll turnover on a cylindrical tube end substantially as herein described with reference to the accompanying drawings.
4. 4. A device for forming a roll turnover on a cylindrical tube end, which device comprises a rigid rod having a transverse turnover groove of smooth rounded bottom profile in which the rim of the tube at the tube end is engaged and drive means whereby said rod may be biassed against and rotated around the tube end so that the tube end follows the contour of the said groove and turns over.
5. 5. A device as claimed in Claim 4 wherein the. drive means comprises a central rotatable drive element from which the grooved rod extends radially.
6. 6. A device as claimed in Claim 4 or Claim 5 wherein the rod is circular in crosssection and is formed with a circumferential groove wherein the tube end is engaged and turned over.
7. 7. A device as claimed in Claim 6 wherein the circular rod is located in a transverse bore in the drive element.
8. 8. A device as claimed in Claim 7 wherein a single rod extends through the drive element, said rod being formed at each end with a groove adjacent to the end, which grooves in operation simultaneously engage the tube end at diametrically opposed positions.
9. 9. A device as claimed in any one of Claims 6 to 8 inclusive wherein the circular rod is angularly adjustable in the bore of the drive element by rotation around its longitudinal axis.
10. 10. A device as claimed in Claim 9 including locking means whereby the rod may be locked in the bore at any desired angle of rotation.
11. 11. A device as claimed in Claim 10 wherein the locking means comprises a set screw in screw engagement with the drive element and in frictional engagement with the rod.
12. 12. A device as claimed in any one of Claims 5 to 11 inclusive comprising a central boss mounted on the drive element which boss is formed as a clearance fit in the turned over tube and is adapted to enter the tube end as the tube rim is engaged in the groove.
13. 13. A device as claimed in Claim 12 wherein the boss is sleeved on a drive shaft and located thereon by the grooved rigid rod extend- ing through coincident bores in the boss and the drive shaft.
14. 14. A device for forming a roll turnover on a cylindrical tube end substantially as herein described and as shown in the accompanying drawings.