FR2604939A1 - Tube-cutting method for a tube-cutter and device for implementing this method - Google Patents

Abstract

The present invention relates to a tube-cutting method for a tube-cutter, and to a device for implementing this method. Method, characterised in that it consists in cutting the tube 1 into various tube portions of equal or unequal length, by successive translations of a cutting carriage 4 supporting a single cutter 5, parallel to the rotational axis 6 of the cutting mandrel 2, of a length, for each translation, equal to the length of the portion of the tube 1 to be cut, also under the control of the numerical control and of the programmable automaton.

Description

 The present invention relates to the field of cutting tubes, and relates to a method for cutting sections of tube having a large diameter, identical or different lengths.

 It is known that the manufacture of paper, cardboard or synthetic material tubes is carried out according to different stages and using different machines, in particular gluing machines, spiraling machines and cutting machines. When the manufacture of a tube is finished, it still remains to cut it into different sections or washers of identical or different lengths, using a tube cutter.

 The tube cutting is usually carried out on a cutter having a cutting module or a cutting mandrel. It is therefore necessary to change the module or the cutting mandrel each time the tube to be cut has a different diameter, the inside diameter of the tube being identical to the diameter of the module or the cutting mandrel, in order to maintain perfect tube when cutting. However, when the diameter of the tubes to be cut is large, that is to say greater than 150 mm, a cutting mandrel is often used, the change of which is then difficult, because of its high weight. This is why the cutters for large diameter tubes have a cutting mandrel with a smaller diameter independent of that of the tube to be cut.

 In order to ensure a cut under good conditions, it is necessary that the thickness of the tube is sufficient, that is to say approximately in a ratio of at least 1 to 100 relative to the diameter of the tube (for example , a thickness of 5mm for a tube with a diameter of 500mm).

For example, a cutter may have the following members - a mechanically welded frame - a head on which is attached the linked cutting mandrel
in rotation - counter rollers tightening the tube to be cut - several cutting assemblies each presenting a knife
free to rotate or driven by a motor, each neck
bucket being mounted on a knife holder, and diving
each knife being controlled by a pneumatic cylinder - a control panel.

 All movements are ensured by DC motors associated with electronic variators or asynchronous motors associated with frequency or mechanical variators.

The operation of such a machine is as follows - prior engagement of a tube, manually by the ope
erator, or automatically - application of the counter-rollers and rotation of the tube; - diving, cutting and removing, simultaneously from all
knives - ejection of cut sections.

 Currently, therefore, cutters for large diameter tubes have a series of individual knives adjustable according to the desired lengths.

 I1 follows a long and tedious setting time. In addition, it is impossible to obtain a section of very small width, because of the own width of the individual knife holders; in fact, when two knives are brought together, the knife holders come into contact and it is no longer possible to bring them closer together. It is therefore impossible to cut a large diameter tube into rings or rings on an existing cutter.

 The present invention aims to overcome these drawbacks.

 It has, in fact, for its object a process for cutting a tube situated on a cutting mandrel driven in rotation and held in place by two counter-rollers also driven, of a tube cutter, under the control of '' a numerical control and a programmable automaton, characterized in that it consists in cutting the tube into different portions of tube of equal or different length, by successive translations of a cutting carriage supporting a single knife, in parallel to the axis of rotation of the cutting mandrel, of equal length, for each translation, to the length of the portion of tube to be cut, also under the control of the digital control and of the programmable controller.

 I1 thus results in a process requiring no adjustment, and making it possible to cut large diameter tubes of any length, even washers or rings.

The invention will be better understood from the description below, which relates to a preferred embodiment, given by way of nonlimiting example and explained with reference to the appended schematic drawings, in which
Figure 1 is a front view of a cutter
s fitted with a cutting device according to the invention
FIG. 2 is a top view of a cutter provided with a cutting device according to the invention, and
Figure 3 is a schematic right view, in section, of an alternative embodiment of a cutter provided with a cutting device according to the invention.

 According to the invention, the cutting method consists in cutting the tube 1 into different tube portions of equal or different length, by successive translations of a cutting carriage 4 supporting a single knife 5, parallel to the axis of rotation 6 of the cutting mandrel 2, of a length equal, for each translation, to the length of the portion of tube 1 to be cut, also under the control of the digital control and of the programmable controller.

The following operations take place, under the control of the digital control and the programmable controller - engagement of the first tube 1 to be cut on the mandrel of
cut 2 either manually or automatically - establishment of a tailstock 7 - rotation of the cutting mandrel 2, and therefore of the tube 1; - rotation of the two counter-rollers 3 - installation of the two counter-rollers 3 so as to
tighten the tube 1 - moving the carriage. cut 4 and therefore knife 5,
and simultaneously detecting the presence of tube 1 on
the cutting mandrel 2 stopping the cutting carriage 4 - plunging the knife 5 free to rotate or beforehand
driven in rotation - cutting of the first portion of the tube 1 considered as
drop portion - removal of the knife 5 - movement of the cutting carriage 4 and therefore of the knife 5
of a length equal to the length of the section to be cut
desired - continuation of operations until the last cut
section of the tube 1 - withdrawal of the knife 5 - spacing and stop of rotation of the two against
rollers 3 stop the rotation of the cutting mandrel 2, and therefore the
tube 1; - removal of tailstock 7 evacuation of all cut sections of tube 1 on
an evacuation support 8 or directly on the ground - delivery of the cutting carriage 4 and therefore of the knife 5 in
its initial position - introduction of the second tube 1 to be cut on the mandrel
cutting 2, either manually or automatically - continuation of operations for all tubes 1 to be cut
until the cutting carriage 4 and therefore the neck are returned
plate 5 in its initial position after the evacuation of
all the cut sections of the last tube 1 to be cut on
an evacuation support 8 or directly on the ground.

 The cutting rate essentially depends on the diameter, the thickness, the cutting length and the quality of the tube 1 to be cut. Before starting the machine, it is therefore necessary to program the cutting lengths on the digital control. For example, if the tube 1 to be cut must be cut into ten sections, each of a different length, the ten numerical values of these lengths will be programmed on the numerical control. Then, the cut will be made by translations of the knife 5, successively of each of these ten programmed lengths.

 The invention also relates to a device for implementing the method, comprising means for cutting the tube 1 into different tube portions of equal or different length, in the form of a cutting carriage 4 on which is mounted a proximity detector 9 as well as the knife 5, and being able to translate parallel to the axis of rotation 6 of the cutting mandrel 2, by means of known translation means 10, such as a ball screw, a rack, a toothed belt, or a pneumatic feed with stopper, or any similar means.

 For example, if the translation means 10 are in the form of a ball screw, this will be driven in rotation by a direct current motor 12, the axis of rotation 13 of which is located in the same vertical plane as that passing through the axis of rotation 6 of the cutting mandrel 2, and on which moves via two axes treated rectified, the cutting carriage 4 (see Figures 1 and 2).

 The translating means 10, whatever it may be, can, of course, be arranged either above or below the cutting mandrel 2. FIG. 1 represents the variant in which the ball screw 10 is arranged above the mandrel cutting 2. The tube 1 is then suspended on the mandrel 2. In FIG. 3, there is shown schematically the variant in which the ball screw 10 is situated below the cutting mandrel 2. The tube 1 is then raised and rests on the counter rollers 3.

 The operation of the cutting device for cutting a tube is as follows: the tube 1 is inserted manually or automatically on the cutting mandrel 2 which is held in place by the tailstock 7. Then, the cutting mandrel 2 is driven in rotation thanks to the motor 14, as well as possibly the counter rollers 3 thanks to the motor 15, which ensure the tightening of the tube 1. The cutting carriage 4 then moves until detection of the tube 1 on the mandrel 2 thanks, for example, to a proximity detector 9 disposed on the carriage 4, and performs a first cut, by pneumatic plunging of the knife 5, of a drop portion. Then, the knife 5 will make as many cuts as there are sections desired, whatever the length of the latter.

 The cutting mandrel may advantageously be provided at its end 18, opposite to that 20 through which the tube 1 to be cut is introduced, with a shoulder 19 for stopping the tube 1, in the immediate vicinity of which is, on the directed side towards the other end 20, a guide shoulder 11 whose section is pointed, and which allows, by tightening the tube 1, by the counter rollers 3, the retention in place of the portion of the tube 1 which remains at cut.

 Indeed, during tightening, by the counter rollers 3, the pointed section will create a groove inside the tube, sufficient to prevent any displacement of the tube 1. Thus, the portion of the tube 1 remaining to be cut will be perfectly held in place without be crushed by the counter rollers 3, thus allowing a precise cut.

 Then, all the cut sections are ejected either on an evacuation support 8, or directly on the ground, using an ejector, for example in the form of a pushing finger 16 held by a slide 17, the pushing being sufficient to eject all the sections, including the last section held in place by the guide shoulder 21.

 Of course, the invention is not limited to the embodiment described and shown in the appended drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements, or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims (4)

- CLAIMS  1. A method of cutting a tube (1) located on a cutting mandrel (2) driven in rotation and held in place by two counter-rollers (3) also driven, of a tube cutter, under the control of '' a digital control and a programmable controller, characterized in that it consists in cutting the tube (1) into different tube portions of equal or different length, by successive translations of a cutting carriage (4) supporting a single knife (5), parallel to the axis of rotation (6) of the cutting mandrel (2), of a length equal, for each translation, to the length of the portion of tube (1) to be cut, also under the control of the digital control and the programmable controller.  2. Cutting method according to claim 1, characterized in that it consists in carrying out the following operations, under the control of the digital control and of the programmable automaton - engagement of the first tube (1) to be cut on the mandrel  cutting (2) either manually or automatically - installation of a tailstock (7) - rotation of the cutting mandrel (2), and therefore of the tu  be (1) - rotation of the two counter rollers (3) - installation of the two counter rollers (3) so that  tighten the tube (1) - movement of the cutting carriage (4) and therefore of the knife  (5), and simultaneously detecting the presence of the tube  (1) on the cutting mandrel (2) - stop of the cutting carriage (4) - plunge of the knife (5) free to rotate or beforehand  rotated; - section of the first portion of the tube (1) considered to be  drop portion - removal of the knife (5) ;; - movement of the cutting carriage (4) and therefore of the knife  (5) of a length equal to the length of the neck section  per desired - continuation of operations until the last cut  section of the tube (1) - withdrawal of the knife (5) - spacing and stop of rotation of the two counter  rollers (3) - stopping the rotation of the cutting mandrel (2), and therefore  tube (1) - removal of the tailstock (7) - evacuation of all cut sections of the tube (1) on  an evacuation support (8) or directly on the ground - handing over the cutting carriage (4) and therefore the knife (5)  in its initial position - introduction of the second tube (1) to be cut on the mandrel  cutting (2) either manually or automatically - continuing operations for all neck tubes (1)  per until the cutting carriage (4) is returned and therefore  knife (5) in its initial position, after evacuating  tion of all the cut sections of the last tube (1)  to be cut on an evacuation support (8) or directly  On the ground.  3. Device for cutting a tube (1) for implementing the method according to any one of claims 1 and 2, characterized in that it comprises means for cutting the tube (1) into different portions of tube of equal or different length, in the form of a cutting carriage (4) on which a proximity sensor (9) and the knife (5) are mounted, and which can translate parallel to the axis of rotation (6 ) of the cutting mandrel (2), by means of known translation means (10), such as a ball screw, a rack, a toothed belt, or a pneumatic feed with stop, or any similar means.  4. Cutting device according to claim 3, characterized in that the cutting mandrel (2) is provided, at its end (18) opposite to that by which the tube (1) to be cut is introduced, with a shoulder ( 19) stopping the tube (1), in the immediate vicinity of which is located, on the side directed towards the other end (20), a guide shoulder (11) whose section is pointed, and which allows, by the tightening of the tube (1) by the counter rollers (3), keeping the portion of the tube (1) which remains to be cut in place.