EP1733819A1 - Cutting punch for punchig out metal sheet - Google Patents

Abstract

The punch (10) has its cutting face equipped with transverse parallel projections (10d) in the shape of teeth on either side of a central bore (10c) forming four chip zones. The teeth lie at a tangent to the bore, with the chip zones located between and outside the teeth, which have a curved surface (10e) in the form of a cradle between them.

Description

The invention relates to the technical sector punching tools and cutting metal sheet metal materials or plates for the conformation of holes.

FIGS. 1 and 2 show the known prior art of the applicant. FIG. 1 shows a punch (1) with two teeth (1a) disposed at the end of the cylindrical body (1b) of the punch considered on its peripheral annular periphery according to the teaching of the patent. FR 2461536 . The teeth are thus shaped with one side a ramp (1c) projecting to end to form the tooth and a vertical wall (1d) vertical junction. There is thus obtained between the two teeth (1a) a semi-circular spiral ramp profile with two opposite walls, the latter being derived from the base of the vertical wall of the tooth. Such a punch makes it possible to cut a piece of sheet-like material into two chips. The problem remains, however, in the efforts made to ensure the cuts, and also and especially the problem of the removal of the resulting chips, and the instability of the punch.

It has been proposed according to the prior art and FIG. 2 in particular a punch (2) including three teeth (2a) arranged at 120 ° on the annular peripheral periphery of the tool, with ramp shapes of the same type as the previous case.

Such a punch has drawbacks, first of all in its cost of manufacturing and machining which is high, and then and especially in the evacuation of the three resulting chips which is often difficult.

The Applicant's approach has therefore been to consider a possible solution to overcome the disadvantages of the prior art, which remains in terms of very competitive manufacturing cost, easy to implement, and is a new proposal for the release of said chips , with optimum stability.

According to a first characteristic of the invention, the cutting punch of metal material of the sheet type, is remarkable in that it is designed and arranged in its front useful part for cutting with profiled projections in the form of teeth arranged transversely in the thickness of the body of the punch and for defining four areas of chips, and in that these transverse and therefore non-radial teeth are arranged parallel and on both sides of the thread by coming substantially tangent with the latter, and in that the four chip cutting zones are arranged parallel and in opposition two by two of the same profile two by two.

According to another characteristic, the punch is remarkable in that the transverse teeth define on their outer side connecting areas with the peripheral periphery of the body of the punches, and in that between the two teeth, is defined a deep curvilinear connection forming a cradle whose bottom comes substantially near or at the level of the last thread of the internal thread of the punch, and in that zones are defined by the cradle shapes situated between the teeth and the internal thread, and in that other zones are defined from the outer flanks of the teeth, and in that the four zones are independent and allow cutting of the worked part into four separate chips.

These and other characteristics will be apparent from the rest of the description.

• la figure 1 est une vue d'un poinçon à deux dents pour la découpe de matériaux avec l'obtention de deux copeaux selon l'art antérieur.
• la figure 2 est une vue d'un poinçon à trois dents pour la découpe de matériaux avec l'obtention de trois copeaux selon l'art antérieur.
• la figure 3 est une vue de face d'un poinçon à deux dents transversales selon l'invention pour la découpe de matériaux avec l'obtention de quatre copeaux.
• la figure 4 est une vue de profil du poinçon selon la figure 3.
• la figure 5 est une vue de dessus du poinçon selon la figure 3.
• la figure 6 est une seconde variante de réalisation proche de celle de la figure 4, dans une vue de côté.
• la figure 7 est une vue de face d'un poinçon à quatre dents transversales selon l'invention dans une troisième mise en oeuvre pour la découpe de matériaux avec l'obtention de quatre copeaux.
• la figure 8 est une vue de profil du poinçon selon la figure 7.
• la figure 9 est une vue semblable à la figure 9, mais avec une rotation d'un quart de tour du poinçon sur lui-même.
• la figure 10 est une vue de dessus selon la figure 7.

For fixing the object of the invention illustrated in a nonlimiting manner to the figures of the drawings where:

• Figure 1 is a view of a punch with two teeth for cutting materials with the production of two chips according to the prior art.
• Figure 2 is a view of a three-tooth punch for cutting materials with obtaining three chips according to the prior art.
• Figure 3 is a front view of a punch with two transverse teeth according to the invention for cutting materials with the production of four chips.
• FIG. 4 is a side view of the punch according to FIG.
• FIG. 5 is a plan view of the punch according to FIG. 3.
• Figure 6 is a second embodiment similar to that of Figure 4, in a side view.
• Figure 7 is a front view of a punch with four transverse teeth according to the invention in a third implementation for cutting materials with the production of four chips.
• FIG. 8 is a profile view of the punch according to FIG. 7.
• Figure 9 is a view similar to Figure 9, but with a quarter-turn rotation of the punch on itself.
• FIG. 10 is a view from above according to FIG.

In order to make the object of the invention more concrete, it is now described in a nonlimiting manner illustrated in the figures of the drawings.

The punch (10) illustrated in its three variants in Figures 3 and 7 has a particular known configuration present in both cases.

This punch (10) comprises a cylindrical body (10a) with in its rear part a knurling (10b) to facilitate handling and an internal tapping (10c) for receiving a tool handle.

According to the invention, the punch (10) is designed and arranged in its front useful part for cutting with protrusions (10d) profiled in the form of teeth arranged transversely in the thickness of the body of the punch and to delimit four zones of chips (C1-C2-C3-C4). These transverse teeth (10d) and therefore non-radial are located parallel and on both sides of the thread (10c) coming substantially tangent with it. The end (10d1) of the teeth can be chamfered or beveled to facilitate penetration into the material and cutting. These transverse teeth (10d) show on their outer side (10d2) connection areas with the periphery of the body of the punches.

Between the two teeth (10d), there is obtained a connection (10e) deep curvilinear cradle whose bottom comes substantially near or at the last thread of the inner thread of the punch. The bottom of the cradle (10e) is level or slightly offset more or less from the end connecting the outer flanks of the teeth with the body of the punch.

There are thus obtained four chip cutting areas (C1-C2-C3-C4) arranged parallel and in opposition two by two of the same profile two by two. Areas (C1) and (C3) are defined by the cradle shapes located between the teeth and the internal thread. Areas (C2) and (C4) are defined from the outer flanks of the teeth. These four areas are independent and allow cutting of the worked part into four separate chips that are evacuated very easily. As shown in the drawings, the teeth transverse to the punch have a length less than the diameter of the punch, but pass through from one side. The orientation of the teeth is therefore very different from that of the prior art.

It should be noted that the internal flanks of the tapping side teeth have clearances in their thickness in extension of the tapping thread showing sharp cutting edges (10h) chips.

In the representation in Figure 3, the outer flanks of the teeth are connected by a smooth slope effect with the corresponding generatrix of the body of the punch.

In the variant of FIG. 7, this connection is made slightly differently with the conformation of lips (10f) in return constituting complementary teeth end parallel to the so-called main teeth (10d). These complementary teeth have a shorter length due to their location, and their height is low, but they are additional anchoring and cutting areas in the material to be cut. The presence of these two complementary teeth (10f) makes it appear with the main teeth (10d) two zones in complementary cradles (10g). By this particular formatting, the cut is further improved.

According to Figures 8 to 11 of the drawings, the punch head has been further improved to optimize the cutting force. According to this implementation, the supplements made to the implementation of the solution provided in FIG. 3 are essentially located on the transverse teeth (10d) and the outer flanks. To improve the quality of the cut, the upper chamfered portion of each tooth (10d) is set in a particular manner by being non-rectilinear and defining a V-shape (10d2) open at an amplitude of 170 to 175 ° with the bottom V in the central part of the tooth. This is achieved by a specific machining. The clearances (10m) from the tapping can even lead into the chamfered part. In addition, clearance angles (10n) are established on the outer flanks of the teeth (10d) to provide a dish configuration and facilitate cutting.

The choice of the three implementations described by the invention will be dictated by the diameters of the punches.

• meilleure évacuation des copeaux au nombre de quatre avec les différentes zones de dégagement réalisées ;
• coût de fabrication plus réduit que ceux générés par la pratique antérieure rappelée au préambule de la description, et temps d'usinage plus réduit;
• meilleur effort de coupe par deux ou quatre dents en sens transversal avec meilleure répartition des efforts de coupe progressifs et sans effort;
• meilleure assise de coupe par le contact et appui des dents transversales sur la pièce à découper.

The solution provided by the invention has many advantages, namely:

• better chip evacuation four in number with the different clearance zones achieved;
• lower manufacturing cost than those generated by the previous practice recalled in the preamble of the description, and shorter machining time;
• better cutting force by two or four teeth in transverse direction with better distribution of progressive and effortless cutting forces;
• better cutting seat by the contact and support of the transverse teeth on the piece to be cut.

Claims (9)

Sheet metal-type metal punch, characterized in that it is designed and arranged in its front useful part for cutting with tooth-shaped projections (10d) arranged transversely in the thickness of the punch body and to define four chip zones (C1-C2-C3-C4), and in that these transverse teeth (10d) and therefore non-radial are arranged parallel and on both sides of the tapping (10c) by coming substantially tangent with the latter, and in that the four chip cutting areas (C1-C2-C3-C4) are arranged parallel and in opposition two by two of the same profile two by two. Punch according to claim 1, characterized in that the transverse teeth (10d) define on their outer side (10d2) connection areas with the peripheral periphery of the body of the punches, and in that between the two teeth (10d), is defined a deep curvilinear connection (10e) forming a cradle whose bottom comes substantially near or at the level of the last thread of the internal thread of the punch, and in that the zones (C1) and (C3) are defined by the cradle shapes situated between the teeth and internal tapping, and that the zones (C2) and (C4) are defined from the outer flanks of the teeth, and in that the four zones are independent and allow cutting of the worked part into four chips distinct. Punch according to claim 2, characterized in that the end (10d1) of the teeth can be chamfered or beveled to facilitate penetration into the material and cutting. Punch according to claim 2, characterized in that the bottom of the cradle (10e) is level or slightly offset more or less with respect to the connecting end of the outer flanks of the teeth with the body of the punch. Punch according to claim 2, characterized in that the transverse teeth (10d) to the punch have a length less than the diameter of the punch, but pass through from one side. Punch according to Claim 2, characterized in that the internal flanks of the tapping-side teeth have, in their thickness, recesses in extension of the tapping thread, revealing sharp cutting edges (10h) of the chips. Punch according to claim 2, characterized in that the outer flanks of the teeth are connected by a smooth slope effect with the corresponding generatrix of the punch body. Punch according to claim 2, characterized in that the connection of the teeth (10d) on its outer flanks with the body of the punch is effected with the conformation of lips (10f) in return constituting complementary teeth end parallel to the teeth (10d). ), and in that these complementary teeth form additional anchoring and cutting zones in the material to be cut. Punch according to claim 2, characterized in that the upper chamfered portion of each tooth (10d) is made non-rectilinear and defining an open V shape with an amplitude of 170 mm. at about 175 ° with the bottom of the V in the central part of the tooth, and in that the clearances (10m) resulting from the tapping can even lead into the chamfered part, and in that recess angles (10n) are established on the outer flanks of the teeth (10d) to provide a bowl configuration and facilitate cutting.

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