EP3009207B1 - Counterform for crossbow-type tube bender - Google Patents

Description

The subject of the present invention is a counterform for a crossbow for bending a tube, substantially in the form of a block whose first and second opposite faces are intended to be placed either one or the other at the contact with said tube, said first face comprising a first transverse groove of substantially semi-cylindrical shape adapted to match a portion of said tube.

Tube bending crossbows are conventionally composed of a half-moon bending shape, and a crossbar supporting a pair of generally identical counter shapes called to cooperate with the half-moon bending shape.

Usually, the pair of bending counterforms is pivotally mounted on the crossbar, so as to gradually follow the movement of each of the linear parts of the tube located on either side of the zone being bent. There are currently different models of counterforms for bending crossbows on the market, suitable for different applications and configurations.

We know in particular from the document FR 2 626 505 an apparatus for bending a crossbow-type tube comprising two pairs of counterforms respectively implemented according to the desired bending radius of the tube. These counterforms have the shape of a block whose two opposite faces each comprise a semicircular groove intended to house a portion of the tube.

The document WO 2012/129345 also describes an apparatus for bending a crossbow-type tube comprising two cobblestone-shaped counter-forms and having two opposite faces equipped with grooves whose profile is adapted to respectively accommodate two different diameters of tube. This is also what the document describes. FR 1 592 154 on which the preamble of claim 1 is based.

Due to their structure, counterforms of this type have sharp outer edges which can sometimes be the source of areas of weakness or untimely deterioration of the tube.

Indeed, in the field, the user of a bending crossbow may have to perform two successive bendings, in an opposite direction, on the same tube, in particular when this tube must span one or more pipes arranged horizontally, it that is to say, to achieve a configuration commonly referred to as a "policeman's hat" or a "bayonet".

During such an operation, to perform the second bending of the tube, one of the two bending counterforms is placed in contact with the curved portion of the tube resulting from the first bending. It has been observed that the sharp edges of the counterform, on which the tube rests, generate two slight recesses on the surface of the latter. These indentations are not only unsightly, but can eventually cause significant damage to the tube.

The present invention aims to overcome this drawback by proposing a bending counterform offering a better contact surface with an already bent portion of a tube, said bending counterform having at least one face devoid of sharp edges, so as to avoid the formation of zones of weakness at the level of the tube, such a counter-shape being furthermore designed in such a way that it allows the bending of tubes of different diameters.

To this end, it relates to a counter form of the kind indicated in the preamble, characterized in that said second face comprises a second transverse groove having a projecting region adapted to provide contact at at least three points with a curved portion of concave appearance of said tube.

In fact, said second groove has a first and a second portion, of substantially semi-frustoconical shape, joined together by their respective smaller side at a junction zone and located relative to each other in such a way such that two straight lines passing respectively through the junction zone and the long side of each of the first and second portions form between them an angle, said long sides extending respectively along two opposite edges of said second face.

Preferably, said angle is between 5° and 50°.

According to a characteristic of the invention, said first and second portions are symmetrical with respect to a plane perpendicular to said second face.

The invention also provides that the ridges formed between the side edges of said first and second portions and the second face of the counterform are rounded.

Similarly, each of the ridges formed at the long side of the first and second portions is rounded.

In another variant not forming part of the invention, the groove has a bottom that looks semi-cylindrical and an upper face that looks convex.

In this case, said upper face may be curved along an arc of a circle with a radius of between 25mm and 55mm.

Furthermore, an additional characteristic of the counterform according to the invention is further defined by the fact that the first groove is arranged to match different tube diameters.

The present application also aims to protect a crossbow for bending a tube, characterized in that it comprises at least one counter form as previously described.

• La figure 1 illustre une vue en perspective d'une variante de réalisation d'une contre forme pour arbalète de cintrage d'un tube selon l'invention,
• La figure 2 représente une vue de profil de la contre forme de la figure 1,
• La figure 3 illustre une vue en perspective d'une autre variante de réalisation d'une contre forme pour arbalète de cintrage d'un tube mais qui ne fait pas partie de l'invention,
• La figure 4 représente une vue de profil de la contre forme de la figure 3, et
• La figure 5 illustre une vue d'une arbalète de cintrage d'un tube équipée d'une paire de contre formes de la figure 1.

The present invention will be better understood on reading the description of exemplary embodiments made with reference to the appended figures, provided by way of non-limiting examples, and in which:

• There figure 1 illustrates a perspective view of an alternative embodiment of a crossbow counterform for bending a tube according to the invention,
• There picture 2 represents a profile view of the counter-form of the figure 1 ,
• There picture 3 illustrates a perspective view of another alternative embodiment of a crossbow counterform for bending a tube but which does not form part of the invention,
• There figure 4 represents a profile view of the counter-form of the picture 3 , And
• There figure 5 illustrates a view of a tube bending crossbow fitted with a pair of counterforms from the figure 1 .

With reference to the figures, the counterforms 1, 10 for crossbow 2 for bending a tube 3, are each substantially in the form of a block 4, 40 comprising an upper face 5, 50 and a lower face 6, 60 interconnected by a through hole 7, 70. This is intended for the passage of an axis of rotation 8 by means of which a counterform 1, 10 is capable of being pivotally mounted on a transverse bar 9 of the crossbow 2 bending to cooperate with the half-moon bending form 11 of the latter (cf. fig. 5 ).

Each of the counterforms 1, 10 also comprises a first and a second opposite faces 12, 13, 120, 130 intended to be placed either one or the other in contact with a portion of the tube 3.

Conventionally, the first face 12, 120 of the counterforms 1, 10 comprises a first transverse groove 14, 140 of substantially semi-cylindrical shape capable of marrying a portion, for example linear, of the tube 3. Preferably, the first transverse groove 14, 140 of the first face 12, 120 of the respective counterforms 1, 10 is profiled in such a way that it can suitably accommodate different diameters of tubes 3, for example from 10 to 22 mm.

Thus, in order to bend, one after the other, tubes 3 of different diameters, it is not systematically necessary to replace one counterform 1, 10 with another counterform 1, 10 different from the previous by its radius of curvature.

The second face 13, 130 comprises a second transverse groove 15, 150 having a protruding region specifically adapted to provide contact at at least three points, or even continuous contact, with an already curved portion 31, of concave appearance, of a tubing 3.

More particularly, in the embodiment variant in accordance with the invention and illustrated in figures 1 and 2 , the second groove 15 of the counterform 1 has a first and a second portion 16, 17, of substantially semi-frustoconical shape, joined together at their respective smaller sides, so as to form a junction zone 18. two portions thus together have an hourglass shape.

In the variant embodiment illustrated, the first and second portions 16, 17 are also symmetrical relative to a plane perpendicular to the second face 13 and are located relative to each other in such a way that two straight lines D1, D2 passing respectively through the junction zone 18 and the long side 19, 20 of each of the first and second portions 16, 17 form between them an angle α, preferably between 5° and 50°.

Furthermore, the long sides 19, 20 of each of the first and second portions 16, 17 extend respectively along each of the side edges 21, 22 of the second face 13.

Furthermore, the ridges 23, 24, 25, 26 formed between the side edges of said first and second portions 16, 17 and the second face 13 of the counterform 1 are advantageously rounded.

Similarly, each of the edges 27, 28 formed at the long side 19, 20 of the first and second portions 16, 17 is rounded.

Such a configuration is advantageous because the hourglass shape of the transverse groove 15 of the second face 13 of the counterform 1 not only makes it possible to accept tubes of different diameters, for example from 10 to 22 mm, like the first groove 14 of the first face 12, but also to avoid marking the tube 3, given the total absence of sharp edges in contact with the considered curved portion of the tube 3. In addition, because the contact between the groove 15 and the curved portion of the tube 3 is increased from two to at least three contacts, the contact force is lowered, with the consequence of a limited marking, or even the absence of marking of the tube 3.

The variant not forming part of the invention and illustrated in figures 3 and 4 has the same advantages. Indeed, the counterform 10 for bending crossbow 2 comprises on its second face 130 intended to come into contact with an already bent portion of a tube 3, a groove 150 which has a bottom 29 of semi-cylindrical shape and a upper face 30 of convex appearance, preferably curved along an arc of a circle with a radius of between 25mm and 55mm, which makes it possible to eliminate any projecting angle on the second face 130. Nevertheless, this configuration does not have the same character adaptability than that of the variant of figures 1 and 2 and requires, for each diameter of tube to be worked, a counterform 10 whose groove 150 is specifically adapted.

Of course, many modifications can be made to the examples described above without departing from the scope of the present invention.

Claims (7)

1. A counter-former (1) for a crossbow bender (2) for bending a pipe (3), said counter-former being substantially in the shape of a block (4, 40) having opposite first and second faces (12, 13) which are intended to be placed on either side in contact with said pipe (3), said first face (12) comprising a first transverse groove (14) of substantially semi-cylindrical shape capable of matching a portion of said pipe (3), characterized in that said second face (13) comprises a second transverse groove (15) having a projecting region suitable for providing at least three points of contact with a curved portion (31) of said pipe (3) of concave shape, said second groove (15) having a first and a second portion (16, 17) of substantially semi-frustoconical shape, which meet at the respective shortest sides thereof at a joining zone (18) and are located relative to each another in such a way that two straight lines (D1, D2) passing respectively through the joining zone (18) and the long side (19, 20) of each of the first and second portions (16, 17) form an angle α therebetween, said long sides (19, 20) extending respectively along each of the lateral edges of said second face (13).
2. The counter-former (1) for a crossbow bender (2) according to claim 1, characterized in that said angle α is between 5° and 50°.
3. The counter-former (1) for a crossbow bender (2) according to either of claims 1 or 2, characterized in that said first and second portions (16, 17) are symmetrical relative to a plane perpendicular to said second face (13).
4. The counter-former (1) for a crossbow bender (2) according to any of claims 1 to 3, characterized in that the ridges formed between the lateral edges (23, 24, 25, 26) of said first and second portions (16, 17) and the second face (13) of the counter-former (1) are rounded.
5. The counter-former (1) for a crossbow bender according to any of claims 1 to 4, characterized in that each of the ridges formed at the long side (19, 20) of the first and second portions (16, 17) is rounded.
6. The counter-former (1, 10) for a crossbow bender according to any of claims 1 to 5, characterized in that the first groove (14, 140) is arranged to match with different pipe (3) diameters.
7. A crossbow bender (2) for bending a pipe (3), characterized in that it comprises at least one counter-former (1, 10) according to any of claims 1 to 6.

Images