IE42568L - Cutting a tube end - Google Patents

Description

- 3 - on each arm at mutually adjacent end regions of the arms, each cutting part comprising at least two cutters, one for cutting the peripheral groove and one for cutting completely through the tube. 5 Preferably the cutters are rotatable about mutually parallel axes of rotation.

Conveniently the cutting tool has three or more cutting parts and the cutting parts are disposed on the arms such that, when a tube to be cut is disposed 10 between the arms and the pincers are closed over the tube so as to bring the cutting parts adjacent the tube, the cutting parts are substantially regularly spaced out around the tube.

In order that the present invention may be more fully understood, reference will now be made, by way 15 of example, to the accompanying drawings. in which: Figure 1 is a perspective vie*, of one end of a tube after being cut by a method according to the present invention; Figure 2 is a side view of part of a cutting tool 20 suitable for carrying out said method, together with a view of the end of the tube in section; Figure 3 is a perspective exploded view of the cutting tool part of Figure 2; Figure 4 is a perspective view of a cutting tool 25 in the form of pincers according to the present invention; Figure 5 is a sectional view of a punch and die capable of being mounted on the arms of the cutting tool of Figure 4 in a variant form of the tool; and 30 Figure 6 is a perspective view of the punch of F i CJ u it © 5 It is known for electrical wiring to pass out of a junction box by way of tubes extending through a wall of the box. Such an assembly comprising a junction box and a plurality of tubes is known as an "octopus". It is also known to manufacture prefabricated building elements, such as concrete panels, with such assemblies integral therewith.

The tubes must be connected to the wall of the junction box by a method which can be rapidly carried out and which provides a reliable connection between each tube and the box. The orifices in the wall of the junction box into which the tubes must be fitted can be formed by drilling or punching, for example. Furthermore it is possible to reinforce the wall of the junction box in the vicinity of the orifices by forming bosses which can be pressed out of the wall of the box in situ, i.e. during manufacture of the box. In certain circumstances, after having drilled or punched out the orifices, a conical punch cf suitable diameter is inserted into the orifices so as to slightly turn down the edges of the orifices and thus provide improved gripping of the tubes .hen the tubes have been inserted in the orifices. However, simple fitting of a tube of constant wall thickness into an orifice provided for that purpose in the wall of the junction box does not provide sufficient resistance against pulling of the tube out of the orifice, "has, in the case in whicii portions of the tubes outsi Therefore it is necessary to improve the connection between each tube and the wall of the junction box. For example it is possible to use a grooved conical connecting element between the tube and the portion of the wall delimiting the orifice. Alternatively the edge of the end of the tube which has been inserted into 42508 - 5 - the junction box may be turned over by means oi special pincers. It is even possible to insert a cotter or a simple nail through the end of the tube inside the junction box. 5 The methods according to the present invention described below with reference to the drawings enable the forming, in a single operation, of one end of a tube in such a manner that the end of the tube so formed can be rapidly inserted into an orifice in a thin wall, such lO as the wall of a junction box, and is securely held therein after insertion.

Referring to 'igure 1, the end of the tube 2 has been formed by completely cutting through a section of tube and at the same time cutting a peripheral groove 15 1 and a chamfer 3 in the outer surface of the tube in the positions shown. The groove and the chamfer have been produced by the tearing away of material whereas the tube has been cut through by shearing.

To perform t! jsu cutting operations, it l:> possible 20 to use a cutting tool comprising one or more cutting parts as shown in Figure 2 and 3. This cutting tool part comprises three cutters, that is a cutting disc 5, a chamfering tool 6 and a gouge 7 for cutting the groove 1, arranged on a common axle 4 so as to be rot-25 able thereon. Guide rollers 8 and 9 are also provided on this axle 4 and are rotatable thereon, the roller 8 serving to space apart the gouge 7 and the chamfering tool 6. In use of a cutting tool comprising three cutting parts as shown in Figures 2 and 3, the three cutting 30 parts are disposed symmetrically about the tube to be cut with their axles 4 parallel to the longitudinal axis of the tube, and the cutting discs 5 are brought into contact with the outer surface of the tube to be cut, and relative movement is caused to take place between 35 each of the cutters and the tube generally tangentially - 6 - with respect to the: tube. This causes the cutting discs S to cut into the outer surface of the tube and, as the: cutting progresses, the axles 4 are moved closer to the longitudinal axis of the tube. After the cutting discs 5 5 have cut into the tube by a certain amount, the gouges 7 and cheunfering tools 6 come into contact with the tube and begin to themselves cut into the tube. The depth of cut of the cutters is determined by the rollers 8 and 9 which bear against the outer surface of the tube lO when the required depth of cut has been reached. When this depth has been reached the cutting discs 5 will have completely cut throu ih the tube.

A particularly convenient torm of cutting tool js shown in Figure 4. This tooJ is in the: form of pincers 1.r) having two arms LO and 11 pivoted to one another at 15 and provided with straight ends 12 and 13. Mutually adjacent end regions of the two arms of the pincers arc-suitably curved inwards towards each other to allow the pincers to be closed around a tube to be cut bv the tool. 20 A cutting part similar to that shown in Figures 2 and 3 is mounted on the arm 11 and two such parts arc mounted on the arm lO in said mutually adjacent end regions of the arms. The cutting discs n£ these parts are indicated in Figure 4 by the reference numeral 14. When the 25 pincers a*-e closed around a tube to be cut by the tooL, the discs 14 should be disposed in a substantially equilateral triangular confiyuration. Two of the said discs and the associated cutters are' arranged each on one of the arms lO and 11, symmetrically in relation to 30 an axis passing through the pivot point 15 of t'se pincers. The third disc 14 and the associated c .tters is supported by a bracket 16 attached to the arm 10 of the pincers and extending into the space between the arms of the pincers. 35 It is quite evident that it would be possible to add further cutting parts similar to that shown in Figures 2 and 3 to the cutting tool provided th.it, when the pincers are closed around a tube, the parts are arranged in a substantially regular array around the tube to be cut.

The cutting parts comprising the cutters are preferably detachable from the remainder of the cutting tool so as to enable the positions in which these parts are mounted to be changed or the parts to be replaced by further parts of a different size, according to the dimensions of tube to be cut. To this end the arms 10 and 11 and the bracket 16 could be provided with a series of transversal drillings in which the axles of the cutting tool parts could be inserted as required.

As the groove to be formed in the tube and the adjacent chamfer must be arranged very close to the end of the tube, the corresponding cutters should be not very far apart from one another on their axles. The cutting parts are therefore arranged on the arms of the pincers with the three -utters and the roller 8 of e.u-li part on one side of the associated arm .mil the roller '» on the other side of the arm, as can be seen in Figure 4 .

In order to render the use of the cutters for cutting the groove and the chamfer as easy as possible, these cutters are arranged as near as possible to the arras of the pincers. The rollers 9 are provided on the other sides of the arms to ensure balance.

The end 12 of the arm 10 of the pincers is provided with a punch 18 and the end 13 of the arm 11 is provided with a die 17, the punch 18 and die 17 being provided for punching a hole in the wall in which the tube is to be fitted, after cutting of the tube. Operating means in the form of a knob 21 is attached to the punch 18 so that the punch 18 may be swivelled during punching t.n make the punching easier. A set of punches and dies is preferably provided with the tool and the punch 18 and 4X9UB 8 die 17 arc preferably detachabl e :;o t.ti.it .1 hole can be punched which corresponds in size to the tube: which has been cut by the tool.

To make punching easier, a punch comprising on its 5 punching face, teeth 19 of the same kind as are found on certain milling tools can be provided. Such a punch is shown in Figure 6 and, in association with the die 17 and the knob 21, in Figure 5. The punch, which is pivotal about its axis, is held on the arm 12 between a lO collar 20 and a knob 21 fixed to the punch by a screw.

In use of the cutting tool of Figure 4, optionally as modified by Figures 5 and 6, the tube to be cut is inserted between the two arms lO, 11 of the pincers, which are partially opened for that purpose, and the 15 latter are then closed around the tube so as to make the cutting discs 14 bear on the outer surface of the tube with only a very short length of tube extending beyond the cutting disc 14. Then, exerting increasing force on the pincers, the cutting tool is swung alternatively 20 backwards and forwards around the tube or the tube is rotated backwards and forwards, the tube being held in one hand while the pincers are held in the other hand. This movement causes the various cutters to cut the tube. After a few movements, the required result is obtained 25 easily and accurately. The dimensions of the cutters should be a function of the dimensions of the tube to be cut so that the cutters have a cutting depth such that the end of the tube is completely cut through as soon as the groove and the chamber have been formed. 30 Subsequently the cuting tool can be used for punching a hole in the wall of the junction box intended to receive the previously formed end of the tube. 42508 - 9 - CLAIMS: - 1. A niotho'l of Mimu 11 .menus I y cui.lin

Claims (1)

1. 42508 - 10 - the cutters are rotatable about mutually parallel axes of rotation. 8. A cutting tool according to claim 6 or 7, wherein two cutting parts are mounted on one arm of the 5 pincers and a third cutting part is mounted on the other arm of the pincers. 9. A cutting tool according to claim 6, 7 or 8, wherein each cutting part comprises three cutters, one for cutting the peripheral groove, one for cutting 10 completely through the tube and one for cutting a chamfer in the tube in the region in which the tube is cut through. 10. A outtin<3 tool according to any one of claims 6 to 9, wherein the cutters of each cutting part are 15 mounted on a common axle of that cutting part. 11. A cutting tool according to any one of claims 6 to 10, wherein the arms of the pincers curve inwards towards each other tt said mutually adjacent end regions. 12. A cutting tool according to any one of claim:; 20 6 to 11, having three or more cutting parts, wherein the cutting parts are disposed on the arms such that, when a tube to be cut is disposed between the arms and the pincers are closed over the tube so as to bring the cutting parts adjacent the tube, the cutting parts are 25 substantially regularly spaced out around the tube;. 13. A cutting tool according to any one of claim:; 6 lo 12, wherein the cutting parts are mounted on the arms in detachable manner. 14. A cutting tool according to any one of claims 30 6 to 13, wherein each cutting part further comprises a guide roller for bearing against the outer surface of the tube. 15. A cutting tool according to claim 14, wherein each cutting part is mounted on the associated arm with 4 2508 -Lilts cutters on one side of the arm and said guide roller on the other side of the arm. 16. A cutting tool according to any one of claims 6 to 15, wherein the ends of the arms in said mutually 5 adjacent end regions are straight, one of said ends bearing a punch and the other of said ends bearing a die, so that the pincers may be used for punching a hole in a wall. 17. A cutting tool according to claim 16, wherein 10 the punch and die are mounted on the arms in detachable Banner. 18. A cutting tool according to claim 16 or 17, wherein the cutting edge of the punch is provided with teeth. 15 19. A cutting tool according to claim 16, 17 or 18, wherein the punch is capable of being rotated about its axis by operating means. 20. A method :£ simultaneously cutting a peripheral groove in the outer surface of a tube and cutting 20 completely through the tube, which method is substantially as hereinbefore described with reference to the accompanying drawings. 21. A cutting tool according to claim 6 and substantially as hereinbefore described with reference 25 to, and as illustrated in, Figures 2 to 4 or these figures as modified by figures 5 and 6 of the accompanying drawings. F. R. KELLY & CO. AGENTS FOR THE APPLICANTS. 4 a b L 8 .3 HhcotH - shout 1 FIG. 2 i FIG.3 *■'• R • KELLY & CO.