EP0268534B1 - Die for a press tool for guiding and positioning a profile in order to punch it - Google Patents

Description

The invention relates to a matrix for guiding and positioning a profile for punching by a tool, in particular a press, provided with at least one movable punch, such as for example that illustrated on the FR-A- 2,310,868.

The dies with which press tools are currently fitted have a single guide section. The technique traditionally used to modify this guide section consists in using removable forks of different widths which are positioned on this matrix. These forks are positioned by means of grooves formed on two parallel faces of the matrix, their maintenance being ensured by pinching these two faces. This method of fixing the forks has a first drawback relating to the difficulty of controlling the clamping forces. In addition, this technique requires having several forks of different widths, adapted to the desired guide dimensions. To make a change of section, it is therefore necessary to carry out disassembly and reassembly operations of these forks. These different manipulations can be the source of errors in the choice of forks; moreover, these can be easily lost in a manufacturing workshop.

Furthermore, when the dies work in overhang, such as for example on tools provided with a movement transformation system, these must have sufficient strength, especially when the guide dimension is relatively small.

The aforementioned technique which requires removal of material along the length of the dies cannot therefore satisfy such use. Given that for the same type of punching, there are generally only three sections of different profile cages, a solution could consist in using at least two workstations: a first workstation with a matrix adapted to present the two most important guide dimensions and using a fork system to pass from one section to another, and a second station provided with a matrix having the smallest guide dimension. However, this solution leads to a multiplication of workstations. In addition, the space available for tools is generally limited, this technique is not always applicable.

A final drawback of this technique resides in the fact that the abutment of the various profiles guided by the matrix is fixed whatever the guide dimension. However, in the field of aluminum carpentry in particular, it is frequent to have to practice the same type of punching on profiles whose section of the cages is different. Only the position of the punch relative to the end of the profile is changed. The presence of a fixed stop therefore requires, in this case, to provide a die for each profile section, the guide length of this die being adapted to the desired punching position. It is understandable that such a solution, which would entail a significant additional cost of production, cannot be adopted.

The present invention proposes to remedy the aforementioned drawbacks of the methods used to modify the guide dimension of a matrix. To this end, the essential objective of the invention is to provide a matrix having at least two guide sections, to each of which is associated a particular stop, this matrix not requiring, in addition, the disassembly or assembly of any element when changing dimension.

Another object is to provide a die with an adjustable position stop for one of the guide sections.

Another objective is to provide a matrix with good strength, allowing guide sections of small dimensions.

Another objective is to allow evacuation of the chips, whatever the orientation of the matrix.

(To simplify the description, the die will be described in its normal mounting position on a tool, the term "before" being used to define the side of the die where the profile is engaged. In addition, the terms "height" and "width" correspond respectively to dimensions perpendicular and parallel to the direction of movement of the punches of the tool).

• un premier élément de guidage (3) de forme allongée, présentant une section transversale de guidage prédéterminée, ledit élément de guidage comportant des lumières (4, 5) d'engagement de l'extrémité de chaque poinçon,
• des moyens de fixation (7, 8, 10) de l'élément de guidage (3) sur l'outil,
• un étrier de guidage (11, 22) porté par l'élément de guidage (3) et présentant une section de guidage plus grande que la section dudit élément de guidage, ledit étrier comportant une extrémité formant butée pour un profilé engagé sur l'élément de guidage (3), et étant adapté pour coulisser longitudinalement sur ledit élément de guidage entre deux positions :
  • . une position avancée où l'étrier (11) chevauche l'élément de guidage (3) sur une longueur déterminée, à partir d'une extrémité longitudinale, dite extrémité avant, dudit élément de guidage,
  • . une position reculée où l'étrier (11) dégage l'élément de guidage (3) sur une longueur de guidage déterminée à partir de son extrémité avant,
• des moyens de blocage (18, 19) en translation de l'étrier (11), aptes à permettre de bloquer ledit étrier et par suite la butée dans une position avancée ou reculée précitées, ou dans une position intermédiaire.

The invention relates to a matrix for guiding and positioning a profile, with a view to punching said profile by a tool, in particular a press, provided with at least one movable punch. According to this invention, this matrix is characterized in that it comprises:

• a first guide element (3) of elongated shape, having a predetermined guide cross section, said guide element comprising slots (4, 5) for engaging the end of each punch,
• fixing means (7, 8, 10) of the guide element (3) on the tool,
• a guide bracket (11, 22) carried by the guide element (3) and having a guide section larger than the section of said guide element, said bracket having an end forming a stop for a profile engaged on the element guide (3), and being adapted to slide longitudinally on said guide element between two positions:
  • . an advanced position where the stirrup (11) overlaps the guide element (3) over a determined length, from a longitudinal end, called the front end, of said guide element,
  • . a retracted position where the stirrup (11) releases the guide element (3) over a guide length determined from its front end,
• locking means (18, 19) in translation of the stirrup (11), capable of making it possible to block said stirrup and consequently the stop in an aforementioned advanced or retracted position, or in an intermediate position.

The guide element may in particular consist of a bar having a uniform guide section over the length which is released in the retracted position of the stirrup.

This matrix therefore has two guide sections, the section change being simply obtained after sliding the stirrup between its advanced and retracted positions and requiring no disassembly. In addition, the end of the stirrup acting as a stop for a section of lower section, the guide length of the bar can be adjusted as desired in order to vary the position of the punching.

• une barre composée de deux tronçons longitudinaux présentant une section de guidage différente, un tronçon avant, de section de guidage déterminée et un tronçon arrière, de section de guidage plus grande;
• des lumières d'engagement de l'extrémité de chaque poinçon;
• un organe mobile articulé sur le tronçon arrière de façon à pouvoir être orienté selon une position fermée où il forme, avec le tronçon avant, un ensemble prolongeant le tronçon arrière et présentant la même section de guidage que le tronçon arrière, ou selon une position ouverte où il dégage le tronçon avant de façon à permettre le guidage d'un profilé par ce dernier;
• un étrier de guidage porté par l'élément de guidage comportant une extrémité formant une butée pour un profilé engagé sur le tronçon arrière de l'élément de guidage et étant adapté pour coulisser longitudinalement et être bloqué sur ledit élément de guidage entre deux positions, et présentant une section de guidage plus grande que celle du tronçon arrière ;
• des moyens de fixation de l'élément de guidage sur l'outil ;
• les deux positions de l'étrier de guidage sur l'élément de guidage, correspondant à
  • . une position avancée où l'étrier chevauche l'élément de guidage sur une longueur déterminée, à partir de l'extrémité longitudinale dudit élément de guidage du côté de la matrice où est engagé le profilé, ladite extrémité avant, et à
  • . une position reculée où l'étrier dégage l'élément de guidage sur une longueur de guidage déterminée à partir de son extrémité avant, et
• des moyens de blocage en translation de l'étrier.

According to a different arrangement, the matrix comprises a guide element comprising:

• a bar composed of two longitudinal sections having a different guide section, a front section, of determined guide section and a rear section, of larger guide section;
• engagement lights at the end of each punch;
• a movable member articulated on the rear section so as to be able to be oriented in a closed position where it forms, with the front section, an assembly extending the rear section and having the same guide section as the rear section, or in an open position where it releases the front section so as to allow the guiding of a profile by the latter;
• a guide bracket carried by the guide element having one end forming a stop for a profile engaged on the rear section of the guide element and being adapted to slide longitudinally and be locked on said guide element between two positions, and having a larger guide section than that of the rear section;
• means for fixing the guide element to the tool;
• the two positions of the guide bracket on the guide element, corresponding to
  • . an advanced position where the stirrup straddles the guide element over a determined length, from the longitudinal end of said guide element on the side of the die where the profile is engaged, said front end, and at
  • . a retracted position where the stirrup releases the guide element over a guide length determined from its front end, and
• means for locking in translation of the stirrup.

This matrix therefore has here three different guide sections, the section changes not requiring any element disassembly. In addition, the rear section advantageously has a longitudinal end acting as a stop for a section of small section engaged on the front section. Thus, each guide dimension corresponds to a stop, the stopping of a large section guided on the stirrup being conventionally provided on the matrix support so as to give this stirrup a guide length greater than the guide lengths. other elements. The guide length of each element is therefore proportional to the dimension of this element.

In addition, the guide length of the intermediate section element can be adjusted at will by locking the stirrup in an intermediate position between its advanced and retracted positions.

According to another characteristic of the invention, the movable member is articulated around an axis of rotation orthogonal to the longitudinal axis of the guide bar, the matrix comprising means for positioning said movable member adapted to block it in rotation, on the one hand in its closed position and, on the other hand, in an open position where it is oriented in a direction substantially orthogonal to the longitudinal axis of the guide bar.

Furthermore, the two sections of the guide bar, and the stirrup are preferably arranged so as to have faces, capable of serving as a support for the fabric for punching profiles, positioned in the same plane. The fabric of the profile is therefore in contact with the matrix over its entire length, regardless of the guide section.

According to another characteristic of the invention, the engagement apertures of each punch are formed transversely in the front section of the guide bar so as to pass right through it. On the other hand, the movable member is provided, facing these lights, with a recessed part opening out at its lower face. The stirrup is, for its part, provided with a lower wing provided with a lumen arranged so as to be opposite the recessed part of the movable member in the advanced position of said stirrup. Thus, whatever the guide section selected, the chips are automatically evacuated for any orientation of the matrix.

According to another characteristic of the invention, the front section of the guide bar, the guide element constituted by the rear section of the guide bar and by the front section and movable member assembly, and the stirrup have a constant height determined as a function of the height of the cages of the profiles to be punched and a width equal, at least over a given length of these elements, to the width of said profile cages.

• la figure 1 est une vue en perspective d'un premier mode de réalisation correspondant à une matrice présentant deux sections de guidage, cette matrice étant représentée dans la position où elle permet le guidage d'un profilé doté d'une cage de grande section,
• la figure 2 en est une vue en perspective dans la position où cette matrice permet le guidage d'un profilé doté d'une cage de petite section,
• la figure 3 en est une coupe transversale par un plan vertical B.B.,
• la figure 4 en est une coupe transversale par un plan vertical A.A.,
• la figure 5 est une vue en perspective d'un deuxième mode de réalisation, correspondant à une matrice présentant trois sections de guidage, cette matrice étant représentée dans la position où elle permet le guidage d'un profilé doté d'une cage de grande section,
• la figure 6 en est une vue en perspective, dans une position où cette matrice permet le guidage d'un profilé doté d'une cage de section intermédiaire,
• la figure 7 en est une vue en perspective, dans une position où cette matrice permet le guidage d'un profilé doté d'une cage de petite section,
• la figure 8 en est une coupe longitudinale par un plan horizontal C.C,
• la figure 9 en est une coupe transversale par un plan vertical D.D, dans la position où cette matrice permet le guidage d'un profilé doté d'une cage de grande section,
• la figure 10 en est une coupe transversale par un plan vertical E.E, dans l a position où cette matrice permet le guidage d'un profilé doté d'une cage de petite section.

Other characteristics and advantages of the invention will emerge from the detailed description which follows and examining the accompanying drawings which show two preferred embodiments. On these drawings which form an integral part of this description:

• FIG. 1 is a perspective view of a first embodiment corresponding to a matrix having two guide sections, this matrix being shown in the position where it allows the guiding of a profile provided with a cage of large section,
• FIG. 2 is a perspective view thereof in the position where this matrix allows the guiding of a profile provided with a cage of small section,
• FIG. 3 is a cross-section through a vertical plane BB,
• FIG. 4 is a cross section thereof through a vertical plane AA,
• Figure 5 is a perspective view of a second embodiment, corresponding to a matrix having three guide sections, this matrix being shown in the position where it allows the guiding of a profile having a cage of large section ,
• FIG. 6 is a perspective view thereof, in a position where this matrix allows the guiding of a profile provided with a cage of intermediate section,
• FIG. 7 is a perspective view thereof, in a position where this matrix allows the guiding of a profile provided with a cage of small section,
• FIG. 8 is a longitudinal section through a horizontal plane CC,
• FIG. 9 is a cross section thereof through a vertical plane DD, in the position where this matrix allows the guiding of a profile provided with a cage of large section,
• Figure 10 is a cross section through a vertical plane EE, in the position where this matrix allows the guiding of a profile with a cage of small section.

The invention relates to dies 1, 2 intended to be mounted, cantilevered, on a tool provided with a movement transformation system, as described in the patent application filed, in the name of the applicant, together with this application. These dies are adapted to present either two or three sections allowing the guiding of profiles of different dimensions, the changes of sections being carried out without any disassembly of elements of these dies.

The accompanying drawings show two alternative embodiments concerning either a matrix 1 which can have two different guide sections (FIGS. 1 to 4), or a matrix 2 which can have three different guide sections (FIGS. 5 to 10).

The matrix shown in Figures 1 to 4 comprises a guide element 3 in the form of a rectangular parallelepiped bar. This bar 3 is provided transversely with two horizontal holes 4, 5 passing right through it, inside which the end of a punch engages. In this case, one of these slots 4 has a circular section and allows the end of a cylindrical punch to be engaged. The second light 5 has, for its part, an oblong shape combined with a shape punch.

The fixing of this bar 3 on the tool is ensured by a yoke 6 provided with two horizontal branches extending relative to one of the lateral faces of this bar, at its rear end. This yoke covers the matrix support, the support of the guide bar 3 being ensured by a fixing screw 7 housed in a transverse bore 8 formed in this bar and opening into the bottom of the yoke 6.

This guide bar 3 also has a fixed stop member 9, having a general T shape. This member 9 is fixed on the lateral face of the bar 3, opposite to the yoke 6, so that the cross member 9a of the T is positioned vertically and oriented towards the front end of the bar. In this position, this stop member 9 constitutes a fixed stop for the end of a straight cut profile.

The abutment member 9 also has a recess 10 formed in its lateral face opposite to the guide bar 3 and opening into the bore 8 of this bar. With a diameter greater than the diameter of the bore 8, this recess makes it possible to house the head of the fixing screw 7.

Furthermore, the cross member 9a of this stop member being located substantially opposite the engagement lumen 5 of the form punch, this cross member 9a has a width less than the width of the upright of the stop member 9, so to preserve a chip evacuation space between this crosspiece and the side face opposite the guide bar 3.

This matrix also includes a guide bracket 11 adapted to guide a profile having a cage height greater than the height of the profile cages guided by the guide bar 3. This bracket 11 comprises two branches 12, 13 of elongated shape and likewise width than the guide bar 3, these branches being arranged so as to cover over a determined length the upper and lower faces of this bar 3.

Each of these branches 12, 13 comprises, towards its rear end, a portion 14, 15 of greater width suitable for covering respectively the upper and lower faces of the guide bar 3 and of the stop member 9.

The two branches 12, 13 are connected laterally at their rear portions 14, 15, by means of a transverse wall 16 bearing against the external face of the stop member 9. This transverse wall 16 is, moreover, provided with a longitudinal opening 17 inside which a screw 18 screwed longitudinally can be screwed into a threaded bore formed in the external face of the stop member 9. The free end of this screw 18, projecting laterally by relative to the transverse wall 16, is provided with a knurled nut 19 making it possible to press and maintain this transverse wall 16 against the external face of the stop member 9.

• une position avancée où l'extrémité avant des portions 14, 15 des branches de cet étrier vient en butée contre la traverse 9a de l'organe de butée 9, et où les branches 12, 13 recouvrent les faces supérieure et inférieure de la barre de guidage 3,
• une position reculée où l'extrémité avant de ces branches 12, 13 se trouve sensiblement alignée avec la face avant de la traverse 9a de l'organe de butée 9.

Thus, the stirrup can be moved relative to the guide bar 3 between two extreme positions:

• an advanced position where the front end portions 14, 15 of the branches of this stirrup abuts against the cross member 9a of the stop member 9, and where the branches 12, 13 cover the upper and lower faces of the guide bar 3,
• a retracted position where the front end of these branches 12, 13 is substantially aligned with the front face of the cross member 9a of the stop member 9.

Furthermore, this stirrup can be locked in translation in any intermediate position between its advanced and retracted positions. The guide length of the guide bar 3 can therefore be adjusted in order to punch the profile at a predetermined distance from its end.

In addition, these dies being generally used for guiding profiles cut in miter, the abutment of the end of these profiles must have a front face inclined at 45 degrees relative to the longitudinal axis of these dies.

Consequently, the front end of the branches 12, 13 is inclined so as to act as a stop at the end of miter cut sections guided by the guide bar 3.

Similarly, the front faces 6a of the branches of the yoke 6 are inclined at 45 ° relative to the axis of the matrix 1. These faces 6a are thus adapted to serve as a fixed stop for the end of a profile cut in tab engaged on the caliper 11.

The surface of this fixed stop is, moreover, increased by means of a stud 20 projecting from the front face of the cross member 9a of the stop member 9. This stud 20 has, in effect, an inclined front face s aligning in the same vertical plane as the faces 6a of the yoke 6.

In addition, the front face 16a of the transverse wall 16 is itself inclined at 45 ° relative to the axis of the matrix. In this way, this face 16a is always set back relative to the surface 6a-20 acting as a stop for a profile engaged on the stirrup 11.

The matrix 2 shown in Figures 5 to 10 has, in turn, three guide elements 21, 22, 23 of different dimensions (width and height), these elements 21, 22, 23 being arranged so as to allow, as before, a change of section without any disassembly of a member of the matrix. This matrix 2 makes it possible to pierce the profiles, of two holes spaced horizontally by a predetermined center distance, depending on the center distance of the punches mounted on the tool. It should be noted that the punching is identical for the different sections of profiles engaged on this die 2.

This die 2 comprises a first guide element 21 adapted to be fixed on the die support of the tool. To this end, it is provided with a housing 24 arranged towards its rear end, and opening at one of its lateral faces. This housing 24 is adapted to accommodate a lateral edge of conjugate shape, of the matrix support. The actual fixing is ensured by means of fixing screws 25 housed in transverse bores opening respectively in the housing 24 and at the level of the opposite lateral face of the guide element 21.

This guide element 21 comprises, first of all, a guide bar 23, 28 composed of two longitudinal sections of different guide section: a front section 23 of determined guide section and a front section 23. These two sections are, in furthermore, arranged so that the longitudinal end 32a of the rear section 28 acts as a stop for a section cut in miter, engaged on the front section 23.

The front section 23 therefore allows the guiding of a profile provided with a cage of small dimensions whose punching fabric comes to bear against one of its lateral faces. This section 23 is, moreover, provided transversely with two horizontal holes 29, 30, passing right through it, and allowing the engagement of the end of a punch. In this case, these slots 29, 30 have a circular section allowing the end of cylindrical punches to be engaged.

• une position fermée où cet organe forme avec le tronçon avant 23, un ensemble prolongeant le tronçon arrière 28 et présentant la même section de guidage que ce tronçon arrière,
• une position ouverte où il est disposé à 90 degrés par rapport à l'axe longitudinal de la barre de guidage de façon à dégager le tronçon avant 23 et à permettre le guidage d'un profilé par ce dernier.

The guide element 21 also comprises a movable member 27 articulated on the rear section 28 so to be able to be oriented in two positions:

• a closed position where this member forms with the front section 23, an assembly extending the rear section 28 and having the same guide section as this rear section,
• an open position where it is arranged at 90 degrees relative to the longitudinal axis of the guide bar so as to release the front section 23 and to allow the guiding of a profile by the latter.

Furthermore, the axis of rotation 31 of this movable member 27 is positioned at an extension 32 of the rear section 28, delimited by two transverse shoulders 33 formed at the upper and lower faces of this section 28. In order to making the connection between the movable member 27 and this extension 32, the rear longidudinal end of this movable member has the shape of a yoke 34 inside which is housed the extension 32, the axis of rotation 31 connecting the wings of this yoke.

It should be noted that the shoulders 33 formed at the upper and lower faces of the rear section 28 have a height suitable for the guide element 21 to have a constant height over its entire guide length, length obtained in the closed position. of the movable member 27. Furthermore, the axis of rotation 31 is not positioned at a weak resistance section, such as the embedding zone of the front section 23, but at the level of the extension 32 having sufficient dimensions to be only slightly weakened by the removal of material resulting from the presence of this axis.

The end of the extension 32 housed inside the yoke 34 of the movable member 27 also has a substantially rounded shape, against which the end of a positioning finger 35 integrated in a longitudinal housing 36 formed inside the movable member 27. The end of this positioning finger 35, kept under pressure on the aforementioned end of the extension 32 by means of a spring 37, is housed , in each of the open and closed positions of the movable member 27, in a notch 38 ensuring perfect indexing in position of this movable member.

Furthermore, the movable member 27 has a side face having the shape of a yoke 39 of dimensions adapted to accommodate the front section 23, in the closed position of this movable member 27. In order to allow the evacuation of the chips in this closed position of the movable member 27, the front section 23 is provided, facing the bottom of the yoke 39, recesses such as 40 inside which open the engagement lights 29-30 of the punches. For its part, the lower wing of the yoke 39 is provided with a cutout 41 ensuring the fall by gravity of the chips.

In addition, the rear face 42 of this movable member is provided inclined so as to define an angle of 45 degrees relative to the axis of the matrix. Thus, this face 42 is always set back with respect to the stop of a profile engaged on the front section 23.

Finally, one of the aims being to guide the profiles between upper and lower faces extending over the entire width of the cage of these profiles, the movable member 27 has, towards its front end, a width, greater than its current width and combined with the predetermined dimensions of the cage of the profiles to be punched. This increase in section is achieved by means of two wings 53 extending, over a given length of the movable member 27, the upper and lower faces of the latter. This choice in fact makes it possible to achieve the intended goal while using a guide element 21 of small bulk, its current section being smaller than the section of the cages of the profiles.

This matrix finally comprises a guide stirrup 22, of greater cross section than the other two guide elements. This bracket has the shape of a U whose wings 43, 44 are arranged parallel to the upper and lower faces of the guide bar and whose length is adapted to overlap this guide bar over a length substantially equivalent to the guide length of the latter.

The two wings 43, 44 of this stirrup 22 are connected by means of a side wall 45 coming to bear against the side face of the guide bar opposite the matrix support. This side wall 45 is, moreover, provided with a longitudinal slot 46 inside which a screw 47 screwed longitudinally can be slid into a threaded bore formed in the side face of the guide bar. The free end of this screw 47, projecting laterally with respect to the side wall 45, is provided with a knurled nut 48 making it possible to press and hold this wall 45 against the abovementioned lateral face of the guide bar.

Thus, this stirrup 22 can be moved longitudinally, relative to the guide element 21 between an advanced position where the wings 43, 44 are superimposed on the upper and lower faces of the guide bar, over a length determined from the front end of this bar and a retracted position where the guide bar is released over a length equivalent to its guide length. Furthermore, this stirrup 22 can be locked in any intermediate position between its advanced and retracted positions.

In addition, in order to allow chip evacuation during the punching of a profile guided by the stirrup 22, the lower wing 44 of the latter is provided with a slot 54 of oblong shape arranged so as to be opposite the cutout 41 of the movable member 27 in the advanced position of this stirrup.

During its movements, the stirrup 22 is guided by means of a longitudinal rib 49 extending on a lateral face of the guide bar, opposite a longitudinal groove 50 of conjugate shape, formed in the lateral wall 45 of the stirrup. In addition, in order to allow movement of the stirrup 22 to an advanced position where it covers the front end of the side wall 45 of this stirrup has two longitudinal grooves 51, inside which the wings 53 are housed defining the section of the guide element 21.

Finally, the front face of the wings 43, 44 of the stirrup is inclined by 45 degrees with respect to the axis of the matrix, so as to serve as a stop at the end of profiles cut in miter guided by the guide element 21. The stop of a profile guided by the stirrup 22 is, in turn, co-located by a shoulder 52 formed on the matrix support.

This matrix 2 therefore has three guide sections to which correspond specific stop positions, the position of the stop of an intermediate section profile being additionally adjustable.

Claims (11)

1. A die for guiding and locating a section member for punching by a tool, inter alia a press tool, having a moving punch, the die being characterised in that it comprises:
   
      A first and elongate guide element (3) having a predetermined guiding cross-section and formed with apertures (4, 5) engageable by the end of each punch;
   
      Means (7, 8, 10) for securing the guide element (3) to the tool;
   
      A guide stirrup (11, 22) carried by the guide element (3) and having a guiding cross-section greater than the cross-section of the guide element (3), the stirrup having an end effective as a stop for a section member engaged on the guide element (3), the stirrup being slidable lengthwise on the guide element (3) between two positions;
   
      A front position, in which the stirrup (11) straddles the guide element (3) over a predetermined length from one longitudinal end, called the front end, of the guide element (3), and
   
      A rear position in which the stirrup (11) is clear of the guide element (3) over a predetermined guiding length from its front end, and
   
      Means (18, 19) for inhibiting displacement of the stirrup (11) and adapted to lock the same and therefore the stop in a front or rear position as previously mentioned or in an intermediate position.
2. A die according to claim 1, characterised in that the guide element is embodied by a bar having a guiding cross-section uniform over the length which is left clear when the stirrup (11) is in its rear position.
3. A die for guiding and locating a section member for punching by a tool, inter alia a press tool, having a moving punch, the die being characterised in that it comprises a guiding element (21) comprising:
   
      A bar (23, 28) embodied by two longitudinal portions each of a different guiding cross-section, viz. a front portion (23) having a predetermined guiding cross-section and a rear portion (28) having a guiding cross-section greater than that of the front portion (23);
   
      Apertures engageable by the end of each punch;
   
      A moving member (27) so pivoted to the rear portion (28) as to be orientable into a closed position, in which it co-operates with the front portion (23) to embody an assembly prolonging the rear portion (28) and having the same guiding cross-section as the rear portion (28), or into an open position, in which it so clears the front portion (23) that the same can guide a section member;
   
      A guide stirrup (22) carried by the guide element (21) and having an end effective as a stop for a section member engaged on the rear portion (28) of the guide element (21), the stirrup being slidable lengthwise and lockable on the guide element (21) between two positions, the stirrup (22) having a guiding cross-section greater than that of the rear portion (28);
   
      Means (25, 26) for securing the guide element (21) to the tool;
   
      The two positions of the guide stirrup (22) on the guide element (21), corresponding to:
   
      A front position, in which the stirrup (22) straddles the guide element (21) over a predetermined length from the longitudinal end, called the front end, of the guide element on that side of the die where the section member is engaged, and to:
   
      A rear position in which the stirrup (22) is clear of the guide element (21) over a predetermined guiding length from its front end, and
   
      Means (47, 48) for inhibiting displacement of the stirrup (22).
4. A die according to claim 3, characterised in that the rear portion (28) has a longitudinal end (42) which is called the front end and which is adapted to be effective as a stop for a section member guided by the front portion (23) of the guide bar.
5. A die according to claim 3 and/or claim 4, characterised in that the moving member (27) is pivotable around a pivot pin (31) perpendicular to the longitudinal axis of the guide bar (23, 28), the die having means (35, 38) for locating the moving member (27) and adapted to lock the same in rotation in its closed position and in an open position in which it extends in a direction substantially perpendicular to the longitudinal axis of the guide bar (23, 28).
6. A die according to claim 5, characterised in that the means (35 - 38) for locating the moving member (27) comprise:
   
      A locating finger (35) received in a recess (36) in the moving member (27), one longitudinal end of such finger being pressed against the pivot pin (31), and
   
      Two recesses (38) so contrived in the pivot pin (31) as to receive the said end of the finger (35) in both the open and closed positions of the moving member (27).
7. A die according to any of claims 3 to 6, characterised in that:
   
      The stirrup (22) has a lateral surface (45) formed with a longitudinal aperture (46) and adapted to bear on a lateral surface of the rear portion (28) of the guide bar, the latter surface being opposite the punches, and
   
      Means for inhibiting displacement of the stirrup (22) comprise a securing screw (47) which is received in the aperture (46) and screwed into the opposite face of the rear portion (28), the screw (47) having at its free end a nut (48) adapted to bear on and maintain the stirrup lateral surface (45) against the surface facing it of the rear portion (28).
8. A die according to claim 7, characterised in that the punch-receiving apertures (29, 30) are so disposed transversely in the front portion (23) of the guide bar (23, 28) as to extend right through the latter, the moving member (27) being formed opposite the apertures (29, 30) with a recessed part (41) opening on to its bottom surface, the stirrup (22) having a bottom arm (44) formed with an aperture (54) which, when the stirrup is in its front position, faces the recessed part (41) of the moving member (27).
9. A die according to claim 7 and/or 8, characterised in that the two portions (23, 28) of the guide bar and the stirrup (22) are adapted to present coplanar surfaces on which the punching pattern of the section members bears.
10. A die according to claim 3, characterised in that the front portion (23) of the guide bar, the guide element (21) embodied by the rear portion (28) of the guide bar and by the assembly embodied by the front portion (23) and moving member (27), together with the stirrup (22), are of a predetermined constant height determined in dependence upon the height of the cages of the section members to be punched and are of a width which over at least a given length of these elements is equal to the width of such cages.
11. A die according to any of claims 1 to 10 adapted to be mounted overhung on a press tool having a movement-converting system adapted to produce a movement of each punch in a predetermined direction other than the operative direction of the press.

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