GB2070999A

GB2070999A - Methods of and apparatus for making lengths of tubing from cylindrical tubes

Info

Publication number: GB2070999A
Application number: GB8106847A
Authority: GB
Original assignee: OHLMEYER C ALLG BAU CHEMIE
Current assignee: OHLMEYER C ALLG BAU CHEMIE
Priority date: 1980-03-06
Filing date: 1981-03-04
Publication date: 1981-09-16
Also published as: ATA75281A; CH653597A5; DE3008616A1; AT379543B; FR2477464A1; GB2070999B; DE3008616C2; FR2477464B1

Abstract

To cut a tube, preferably of plastics, into lengths of tubing, the tube is inserted into a tubular guide and one end of the tube is clamped in a clamp (10), whereupon the tube is rotated and cut into lengths by successively actuating a plurality of severing units (6) in the direction towards the clamped end (9), starting with the unit (6) furthest away from the clamped end (9). Each severing unit (6) comprises a cutting knife movable into contact with the rotating tube via a slot in the guide. Initially, tubes are stacked on an oblique surface (23) between webs (26) and under bands (24). For feeding to the guide, a bottom tube, previously held by a beam above a trough, is released by beam retraction, by piston-cylinder units (28). The tube falls into the trough. A mandrel on a guide (31) moves longitudinally to push the tube to the clamp (10), removing the previously-severed lengths to a hopper (35). <IMAGE>

Description

SPECIFICATION Methods of and apparatus for making lengths of tubing from cylindrical tubes This invention relates to methods of and apparatus for making lengths of tubing from cylindrical tubes.

According to a first aspect of the invention there is provided a method of making lengths of tubing from a cylindrical tube, wherein: the cylindrical tube is inserted into a tubular guide; an end of the cylindrical tube, projecting from the tubular guide at an end of the guide remote from the end into which the cylindrical tube was fed in, is clamped; the cylindrical tube is rotated; and the cylindrical tube is divided into lengths of tubing by severing units arranged on the tubular guide by bringing a cutting knife of each severing unit into the path of rotation of the cylindrical tube, through a slot in the tubular guide, the severing units being successively actuated in the direction towards the clamped end of the tube, starting with the severing unit nearer or nearest the other end of the tube.

According to a second aspect of the invention there is provided apparatus for making lengths of tubing from a cylindrical tube, the apparatus comprising: a tubular guide into which the cylindrical tube can be inserted via one end of the guide; clamping means capable of clamping an end of the tube projecting from the other end of the tubular guide; means for rotating the clamped tube; and a plurality of severing units arranged on the tubular guide and each comprising cutting knife movable through a slot in the tubular guide into the path of rotation of the cylindrical tube whereby the cylindrical tube can be divided into lengths of tubing by actuating the severing units successively in the direction towards the clamped end of the tube, starting with the severing unit nearer or nearest the other end of the tube.

The lengths of tubing can be used, for example, as winding cores for gauze bandages, for strips of paper or plastics or the like. With a preferred embodiment of the invention described below, identical or different lengths of tubing, of accurate shape and size, can be obtained from a cylindrical tube with high output, the preferred apparatus being constructed simply and operating without any trouble.

Preferably, the cylindrical tube to be cut into lengths of tubing is inserted into the tubular guide from a magazine by means of a mandrel which can enter an outer end of the tube and move over the whole length of the magazine, during which operation the lengths of tubing from a cylindrical tube previously divided up are transported through a central chamber of the clamping means into a collecting vessel or other receptacle.

It is an advantage for the tubular guide to be made of an electrically conductive material which conducts heat well, e.g. metal, in particular if the tube to be divided up is made of plastics.

If the tubular guide is made of a material which conducts heat well, the frictional heat which develops during the rotation of a plastics cylindrical tube will be dissipated through the guide, so that no additional cooling means will be required.

Electrostatic charge formed during rotation of a plastics cylindrical tube can be led away through an earthed metal tubular guide.

The preferred apparatus embodying the invention described hereinbelow can carry out the cutting operations without forming dust or burrs.

With methods embodying the invention a high manufacturing output can be obtained, since there are only short idle periods during operation. When a new tube, which has to be divided, is placed in the machine, only one clamping operation is necessary, at one end of the tube.

The invention will now be further described, by way of illustrative and non-limiting example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of apparatus embodying the invention, showing an associated magazine for cylindrical tubes to be divided; Figure 2 is a part-sectional plan view of the apparatus, showing a tubular guide, severing units disposed on the guide, clamping means and drive means for a cylindrical tube to be divided; Figure 3 is a fragmentary section taken along the line Ill-Ill in Fig. 2; Figure 4 is a perspective view of the clamping means of the apparatus; Figure 5 is a perspective view of a transitional region between the magazine and the rest of the apparatus; and Figure 6 shows the same transitional region as Fig. 5, but from a different angle.

The illustrated apparatus for making lengths of tubing from a cylindrical tube 1, e.g. made of plastics, comprises a tubular guide 2 carried by uprights 3 which are fixed on a table 4 forming part of the apparatus. The tubular guide 2 is of an electrically conductive material which conducts heat well, e.g. a metal.

The table 4 rests on a stand 5.

Severing units 6 are mounted for sliding movement on the tubular guide 2. In the illustrated exemplary embodiment the severing units 6 are arrested in desired positions by spacing sleeves 7, the spacing sleeves being provided between respective adjacent pairs of the units 6. Nuts 8 are screwed onto the ends of the guide 2 and may be used as stops for the outer severing units 6.

By selecting spacing sleeves 7 of equal or different lengths, the severing units 6 may be distributed along the length of the tubular guide 2 at equal or different intervals, so that equal or different lengths of tubing can be cut from the tube 1.

An end 9 of the cylindrical tube 1 inserted in the tubular guide 2 is fixed in a clamping means 10. the clamping means 10 can be rotatably driven by a motor 11 and a drive belt 12. During operation the cylindrical tube 1 to be severed may rotate at, for example, 3,000 revolutions per minute.

Each severing unit 6 is equipped with a cutting knife 13 which is fixed to a beam 14.

The beam 14, which extends horizontally, is mounted for sliding movement on vertical guiding bars 15 and supported on springs 16.

The guiding bars 15 are fixed to a pedestal 18 by screws 17, the pedestal engaging round the tubular guide 2 through an angular range of over 1 80". The beam 14 and thus the cutting knife 1 3 are movable against the action of the springs 16 by means of a pistonand-cylinder unit 19 which is operable by means of compressed air. The tubular guide 2 is equipped with a slot 20 at its side facing the knife 13. The knife 13 can be moved through the slot 20 into the path of rotation of the cylindrical tube 1 and thereby cut through the cylindrical tube.

The tube 1, when clamped at its end 9 and rotated, can be cut into lengths of tubing by firstly actuating the severing unit 6 furthest away from the clamping means 10. Following on from this unit, the severing units 6 are then actuated in succession, working towards the clamped end 9 of the tube 1, so that during each cutting operation the part of the tube 1 which has not yet been cut rotates.

It will be seen from Fig. 1 that the tubes 1 to be cut are fed to the tubular guide 2 from a magazine 21. The magazine 21 has a troughshaped guide 22 for a cylindrical tube 1. One cylindrical tube at a time is fed to the guide 22 from a supporting surface 23, which extends obliquely upwardly from the guide 22.

Straps or struts 24 extend parallel to the supporting surface 23 at a spacing corresponding to the diameter of the tubes 1. The free ends of the straps 24 each have an angled portion 25 extending away from the supporting surface 23. The supporting surface 23 is bounded at it sides by webs 26, so that the tubes 1 can be inserted into the magazine 21 from above and held in position by the straps 24. The bottom tube, located above the trough-shaped guide 22, is supported against a profiled member 27 that extends over nearly the whole of the length of the magazine 21.

The member 27 can be moved away from the guide 22 by means of piston-and-cylinder units 28. so that in the lowermost position of the profile 27 a cylindrical tube can drop into the guide 22. At its rear end, the tube lying in the guide 22 is engagable by a mandrel 29 for transporting the tube to the tubular guide 2. The mandrel 29 is fixed to a web 30, which extends into the trough-shaped guide 22 through a longitudinal slot in its base, and which is fixed at the bottom to a slide 31. The slide 31 is mounted for sliding movement along guide rails 32 provided below a base plate 33, the member 27 being mounted for sliding movement on the base plate 33.

By means of the mandrel 29 the cylindrical tube is pushed out of the trough-shaped guide 22 of the magazine 21 and into the tubular guide 2. In the course of this movement it conveys the lengths of tubing remaining in the tubular guide 2 from the tube that was previously cut up to a central chamber 34 of the clamping means 10 and to a transfer hopper 35. From here the lengths of tubing pass into a collecting container or other receptacle.

The end 9 of the newly inserted tube 1 is then clamped and the tube set in rotation, so that it can be cut up into lengths by the.

severing units 6.

Claims

1. A method of making lengths of tubing from a cylindrical tube, wherein: the cylindrical tube is inserted into a tubular guide; an end of the cylindrical tube, projecting from the tubular guide at an end of the guide remote from the end into which the cylindrical tube was fed in, is clamped; the cylindrical tube is rotated; and the cylindrical tube is divided into lengths of tubing by severing units arranged on the tubular guide by bringing a cutting knife of each severing unit into the path of rotation of the cylindrical tube, through a slot in the tubular guide, the severing units being successively actuated in the direction towards the clamped end of the tube, starting with the severing unit nearer or nearest the other end of the tube.

2. A method according to claim 1, wherein the cylindrical tube is inserted into the tubular guide from a magazine by means of a mandrel which can enter an outer end of the tube and move over the whole length of the magazine, and wherein during such operation the lengths of tubing from a cylindrical tube previously divided up are transported through a central chamber of clamping means operative to effect said clamping into a col lecting vessel or other receptacle.

3. A method according to claim 1 or claim 2, wherein the cylindrical tube is of plastics.

4. A method according to claim 1, claim 2 or claim 3, wherein the tubular guide is of an electrically conductive material which con ducts heat well, such as metal.

5. A method of making lengths of tubing from a cylindrical tube, the method being substantially as herein described with reference to the accompanying drawings.

6. Apparatus for making lengths of tubing from a cylindrical tube, the apparatus comprising: a tubular guide into which the cylindrical tube can be inserted via one end of the guide; clamping means capable of clamping an end of the tube projecting from the other end of the tubular guide; means for rotating the clamped tube; and a plurality of severing units arranged on the tubular guide and each comprising a cutting knife movable through a slot in the tubular guide into the path of rotation of the cylindrical tube whereby the cylindrical tube can be divided into lengths of tubing by actuating the severing units successively in the direction towards the clamped end of the tube, starting with the severing unit nearer or nearest the other end of the tube.

7. Apparatus according to claim 6, wherein the severing units are fixed on the tubular guide and displaceable longitudinally of it.

8. Apparatus according to claim 7, wherein a spacing sleeve surrounding the tubular guide is provided between a pair of adjacent severing units.

9. Apparatus according to any one of claims 6 to 8, wherein the severing units each comprise a beam which carries a cutting knife and which can be moved along guide means towards the tubular guide, by means of a piston and cylinder unit, against the action of springs.

10. Apparatus according to any one of claims 6 to 9, including a magazine from which a cylindrical tube can be inserted into the tubular guide by means of a mandrel which can enter an outer end of the tube and move over the whole length of the magazine, during which operation the lengths of tubing from a cylindrical tube previously divided up are transported through a central chamber of the clamping means into a collecting vessel or other receptacle.

11. Apparatus according to claim 10.

wherein the magazine has, at a lower longitudinal side thereof, a trough-shaped guide for a cylindrical tube, the magazine also having a supporting surface for cylindrical tubes therein, the supporting surface extending obliquely upwardly from the trough-shaped guide, and struts that extend parallel with the supporting surface at a spacing corresponding to the diameter of the tubes and have free ends that are angled away from the supporting surface.

12. Apparatus according to claim 11, comprising a member disposed so that the bottom cylindrical tube located above the trough-shaped guide can rest against the member, the member extending for nearly th whole length of the magazine and being mov able away from the trough-shaped guide by piston and cylinder units to release the bottor tube.

13. Apparatus according to claim 11 or claim 12, wherein a horizontal base plate extends from a front edge of the troughshaped guide and has said member mounted on it for sliding movement, guide rails for the mandrel are provided below the base plate, and the mandrel is fixed to a web which passes through a longitudinal slot in the base of the trough-shaped guide.

14. Apparatus according to claim 13, wherein the web is fixed to a slide which is movable along the guide rails.

15. Apparatus according to any one of claims 6 to 14, wherein the tubular guide is of electrically conductive material which conducts heat well, such as metal.

16. Apparatus for making lengths of tubing from a cylindrical tube, the apparatus being substantially as herein described with reference to the accompanying drawings.