FR2984190A1 - Centering device for facilitating closing of press tool for stamping body part of car, has guidance ring comprising truncated central opening for allowing pre-centering and centering of guidance column with respect to guidance ring - Google Patents

Abstract

The device has a guidance ring (8) fixed at an upper part (3) and a lower part (2) of a stamping tool (1) by a support (10) that completely covers the guidance ring, where the material of the support contains polyamide or tender metal. The guidance ring comprises a truncated central opening (10c) coaxial with the guidance ring for allowing a pre-centering and a centering of a corresponding guidance column (6) with respect to the guidance ring during closing of the upper and lower parts of the stamping tool to engage the guidance column in the guidance ring. An independent claim is also included for a method for closing a stamping tool.

Description

The present invention relates to a centering device making it possible to facilitate the closing of a press tool with the aid of a centering device of a press tool. a stamping press. Figure 1 is a schematic vertical sectional view of a press tool 1 of a stamping press, for example sheet metal parts of the body of motor vehicles, and forming part of the prior art. The press tool 1 comprises a lower part 2 which is fixed and an upper part 3 which is movable substantially vertically towards the lower part 2 so that the press tool 1 occupies a closed position and is then in its closed position. , transferred and fixed in a stamping press. The closing operation of the press tool 1 is carried out using an overhead crane symbolized by the reference 4 to which is suspended by slings 5 the upper part 3 of the press tool 1. The part upper 3 of the press tool 1 is equipped with hardened steel columns 6, for example four in number, only two columns 6 being shown, whose upper end parts are force-fitted, for example with nitrogen or by rods, in holes 7 of the upper part 3 so that the columns 6 extend perpendicularly to the lower face 3a of the upper part 3 projecting from this face. The lower part 2 of the press tool 1 is equipped with guide rings 8, for example bronze, fixed in bores 9 of the lower part 2 and 35 of a number identical to that of the guide columns 6. Each guide ring 8 comprises in the vicinity of the end 8a of the ring 8 projecting from the lower face 2a of the lower portion 2 of the press tool 1, a flange 8b bearing on the face 2a. Each fixing ring 8 is fixed to the face 2a of the lower part 2 by two fastening flanges 10 integral with the face 2a, diametrically opposed and bearing on the flange 8b of the ring 8, as is also apparent from FIG. 2. Each flange 10 is fixed on the face 2a of the lower part 2 by a fixing screw, not shown, passing through a hole 10a of the flange 10 and anchored in a threaded blind hole in the lower part 2. The upper end 8a of each guide ring 8 protrudes from the two fastening flanges 10.

Previously, the guide tool 1 was equipped with guide plates, not shown, which allowed pre-centering of the two lower 2 and upper 3 parts before the engagement of the guide columns 6 in their respective guide rings 8 during the closing operation of the press tool 1. However, in the context of production management of stamping presses using such press tools to increase productivity, these guide plates have been removed.

Under these conditions, the removal of the guide plates has eliminated the pre-centering function and only the columns 6 then allow pre-centering and centering of the upper part 3 on the lower part 2 when closing the tool press 1.

However, the crane 4 is made to handle each upper portion 3 of a press tool 1 weighing several tons, so that when placing the upper part 3 on the lower part 2, the guide columns 6 of the upper part 3 are not always aligned with the guide rings 8 of the lower part 2. Therefore, the slightest misalignment of the guide columns 6 of hard material, such as hardened steel, leads them to clash with the guide rings 8 of soft material, for example bronze, as shown in Figure 3, leading to a deterioration of these guide rings.

The present invention aims to overcome the above disadvantages by providing a solution preventing the deterioration of the guide rings by the guide columns during the closure of the press tool.

For this purpose, according to the invention, the centering device for facilitating the closure of a press tool comprising an upper part and a lower part, said device comprising at least two guiding columns integral with one of the upper parts and lower of the press tool, able to engage, when closing the press tool, respectively in two guide rings fixed by clamping in the other of the two upper and lower parts of the press tool , characterized in that each guide ring is attached to the other of the two upper and lower portions of the press tool by a single flange completely covering the guide ring and having a frustoconical central orifice coaxial with the guide ring in extension of the latter and allowing the pre-centering and centering of the corresponding guide column relative to the guide ring when closing the two upper parts re and bottom of the press tool to engage the guide column in the guide ring.

Preferably, the fixing flange is made of a material of lower hardness than that of a guide column. Advantageously, the material of the fixing flange is based on polyamide or a soft metal.

Each guide ring comprises a collar formed in the vicinity of the free end of the guide ring and which bears on one face of the other of the two upper and lower parts of the press tool and the part of the flange. covering the guide ring has a shape complementary to that of the free end and the collar of this ring.

The flange advantageously has a generally square outer shape and is fixed to the other of the two upper and lower parts of the press tool by four fixing screws. The invention also relates to a method for centrally closing a press tool for a press, in particular stamping, and using the centering device as defined above, which is characterized in that it consists in moving one towards the other. the other two upper and lower parts of the press tool so that each end of a guide column can dock the frustoconical central orifice of the flange to ensure the pre-centering of the guide column relative to the ring for guiding and continuing the movement of the two parts of the press tool towards each other so that each end of a guide column is centered by the frustoconical central orifice of the flange to engage it in the guide ring to the closed position of the press tool.

The invention will be better understood, and other objects, characteristics, details and advantages thereof will appear more clearly in the explanatory description which will follow with reference to the accompanying drawings given solely by way of example illustrating an embodiment. of the invention and in which: - Figure 1 is a schematic vertical sectional view of a press tool of the prior art; - Figure 2 is a top view along the arrow II of Figure 1 without a guide column; - Figure 3 is a partial schematic sectional view showing the docking of a guide column relative to a guide ring of the press tool of Figure 1; - Figure 4 is a schematic partial vertical sectional view of a press tool comprising a flange according to the invention for fixing a guide ring, to pre-center and center the guide column relative to this ring; - Figure 5 is a top view along the arrow V of Figure 4; - Figure 6 is a view similar to that of Figure 4 and showing the pre-centering phase of the guide column relative to the fixing flange of the guide ring; Fig. 7 is an enlarged view of Fig. 6 and showing in detail engagement of the end of the guide column in the attachment flange before engagement with the guide ring; and FIG. 8 is a view similar to that of FIG. 6 and showing engagement of an end portion of the guide column in the corresponding guide ring. The invention will be described in the application to a press tool of a press forming part of a stamping line comprising a main stamping tool of parts followed by recovery tools for carrying out finishing operations. , such as cutting or punching parts. Such parts may be constituted by the sheet metal parts of the body or body of automobile vehicles. By press tool, it will be understood that it may be a main stamping tool or a recovery tool. The components or elements which will be described in FIGS. 4 to 8 and identical to those described with reference to FIGS. 1 to 3 or performing the same function as these bear the same references.

Referring to FIGS. 4 to 8, the press tool 1 comprises a fixed lower part 2 and a movable upper part 3 to which several columns 6, for example four in number, of which only one is represented, are fixed and which protrude perpendicularly from the lower face 3a of the upper part 3. Each column 6 is made of hard material, such as, for example, hardened steel and is force-fitted, for example with nitrogen, into a bore 7 The upper part 3 is suspended from an overhead crane by slings, as in FIG. 1. The lower part 2 of the press tool 1 is equipped with guide rings 8 secured in bores 9 of FIGS. the lower part 2 and a number identical to that of the guide columns 6. The upper end portion of each guide ring 8 and protruding from the upper face 2a of the lower part 2 of the press tool 1, understand a flange 8b bearing on the face 2a and which is formed near the upper end 8b of the ring 8 projecting above the flange 8b. In the closed position of the upper part 3 on the lower part 2 of the press tool 1, the guide columns 6 are introduced through the respective guide rings 8 as shown in FIG. 4. According to the invention, each 8 is fixed in the lower part 2 of the press tool 1 by a single fastening flange 10 which completely covers or caps the upper end portion of the ring 8 projecting from the face 2a of the part 2 and which is constituted by the flange 8b and the upper end 8a of this ring. Thus, the fastening flange 10 comprises a central orifice 10b made in its lower part and of a height approximately equal to half the total height H of the fastening flange 10 from the face 2a, central portion 10a of shape conjugate to the upper end 8a and the flange 8b of the guide ring 8. Under these conditions, the fastening flange 10 completely covering the upper end 8a and the flange 8b of the ring 8 provides protection of the upper part of this ring.

In addition, each fastening flange 10 has in its upper part a height approximately equal to half the total height H of this flange, a frustoconical central orifice 10c extending coaxilament the lower central orifice 10b of this flange being disposed above it. Thus, the frustoconical central orifice 10c diverges upwardly from an internal shoulder 10d of the flange 10 situated just above the upper face 8c of the end 8a of the ring 8, as can be seen more clearly from FIG. 7. This figure shows that the shoulder 10d of the flange 10 is arranged with a small clearance above the upper face 8c of the ring 8, the flange 10 being supported on the flange 8b of the ring 8 by a shoulder internal lower 10th of this flange.

In order not to damage each guide column 6 during its pre-centering and its centering relative to the corresponding fastening flange before engaging in the guide ring 8, the flange 10 is made of a soft material with respect to hard material constituting the column 6. For example, the material constituting each fastening flange 10 may be based on polyamide, but the material constituting this flange may be a soft metal material such as for example XC38 steel or bronze.

The free end of each guide column 6 is provided with a chamfer 6a.

As best shown in FIG. 5, each fastening flange 10 has a generally square outer shape and is fixed on the face 2a of the lower part 2 by four fastening screws, not shown, passing through four bores 10a of the flange 10 made at the four corners of it. FIGS. 6 to 8 show the pre-centering and centering phases of each guide column 6 relative to the corresponding guide ring 8 and of engagement of the column in this ring during the closing operation of the upper part. 3 on the lower part 2 of the press tool 1. Thus, during this closing operation, the crane is manipulated so as to move the upper part 3 towards the lower part 2 of the press tool 1 until to dock the lower end of each guide column 6 with the frustoconical inlet 10c of the fastening flange 10 to ensure the pre-centering of the column relative to the flange 10 and, therefore, to the ring of guidance 8. Then, continuing to vertically descend the upper part 3 towards the lower part 2 of the press tool 1, the lower end of each guide column 6 slides along the frustoconical central orifice 10c of the flange 10 to a substantially centered position in the flange 10 as shown in Figure 7 and continuing to lower the upper portion 3 relative to the lower portion 2, the lower end portion of the column 6 is engaged coaxially in the ring 8 as shown in FIG. 8 and continues to engage therein to the closed position of the press tool 1. Various modifications may be made without departing from the scope of the present invention.

Thus, each guide column 6 can be secured to the lower portion 2 of the press tool 1 and each guide ring 8 would then be integral with the upper portion 3 of this tool. In addition, each fastening flange 10, instead of having a generally square outer shape, could have a circular outer shape. The pre-centering and centering flange according to the invention makes it possible to reduce the closing time of the press tool 1 compared with the closing time of the press tool of the prior art as represented in FIG. 1. In addition, the flange of the invention effectively protects the centering ring of shocks of the corresponding guide column during the closing operation of the press tool, so that each guide ring is not deteriorated and no longer needs to be replaced, thereby reducing costs.

Claims (6)

REVENDICATIONS1. Centering device for facilitating the closure of a press tool (1) comprising an upper part (3) and a lower part (2), said device comprising at least two guide columns (6) integral with one of the upper (3) and lower (2) parts of the press tool (1), able to engage, when closing the press tool (1), respectively in two guide rings (8) clamped in the other of the two upper (3) and lower (2) parts of the press tool (1), characterized in that each guide ring (8) is attached to the other of the two upper parts (3) and lower (2) of the press tool (1) by a single flange (10) completely covering the guide ring (8) and having a frustoconical central orifice (10c) coaxial with the guide ring ( 8) extending from the latter and allowing pre-centering and centering of the corresponding guide column (6) relative to the ring for guiding (8) when closing the two upper (3) and lower (2) parts of the press tool (1) to engage the guide column (6) in the guide ring (8). 25 2. Device according to claim 1, characterized in that the fixing flange (10) is made of a material of lower hardness than that of a guide column (6). 3. Device according to claim 2, characterized in that the material of the fixing flange (10) is based on polyamide or a soft metal. 4. Device according to one of the preceding claims, characterized in that each guide ring (8) comprises a flange (8b) formed in the vicinity of the free end of the guide ring (8) and which is supported on one side (2a; 3a) of the other of the two upper (3) and lower (2) parts of the press tool (1) and in that the portion of the flange (10) covering the guide ring ( 8) has a shape complementary to that of the free end (8a) and the collar (8b) of this ring. 5. Device according to one of the preceding claims, characterized in that the flange (10) has a generally square outer shape and is fixed to the other of the two upper parts (3) and lower (2) of the tool press (1) by four fixing screws. 6. A method of centrally closing a press tool (1) for a pressing press and particularly using the centering device as defined in any one of the preceding claims, characterized in that it consists in moving the the two upper (3) and lower (2) portions of the press tool (1) towards each other so that each end of a guide column (6) can dock with the frustoconical central orifice (10c ) of the flange (10) to pre-center the guide column (6) relative to the guide ring (8) and to continue the displacement of the two parts (2,3) of the press tool (1) so that each end of a guide column (6) is centered by the frustoconical central orifice (10c) of the flange (10) to engage it in the guide ring ( 8) to the closing position of the press tool (1).