EP1274538B1 - Centring and clamping control tool - Google Patents

Description

The present invention relates to the field of centering and clamping tools for handling parts to be fixed in position such as sheets and, more particularly, a tool for centering and clamping at least one part having a through passage and adjusted for said tool, of the type comprising a pilot member carried at the end of a housing, clamping members and means for driving the clamping members between a centering position in which they are erased in the pilot member and a plurality of clamping positions in which the clamping members protrude outside the pilot member and resting on the workpiece (see for example EP-A-0 911 112).

Known clamping tools generally comprise a hydraulic or pneumatic cylinder for actuating a clamping member such as a clamping arm which is pivotally drivable between an active clamping position on the workpiece and an inoperative position. Such a tool may also include a driver which is introduced into a passage in the workpiece, which allows to center the workpiece correctly on the tool.

FR-A-2,340,798 discloses a clamping tool including a clamping arm abuts against the workpiece to be clamped by pivotally driving the clamping arm. This pivoting drive of the clamping arm between the loosening position and the clamping position is obtained by means of an articulated linkage mounted on a rod driven in linear displacement by a jack.

This movement in pivoting of the clamping arm in this type of clamping tool has the disadvantage that, with certain parts to be treated, poor tightening is obtained, for example when the surface of the workpiece is not perfectly flat. In this case, the clamping arm is not always correctly positioned on the workpiece and does not guarantee a good tightening. There is also the risk of deformation of the part.

In addition, in the case of a clamping tool provided with a pilot, the point of contact of the clamping arm on the workpiece is relatively distant from the centering point of the tool on said workpiece, which can cause a certain imbalance or requires a more complex structure of the tool.

It was then proposed, as in WO-A-9635547, a tool provided with clamping jaws. Such a tool comprises an indexing device of a part through a hole of this part and comprising a sleeve having an upper face forming a support for the part, a piston mounted in the sleeve to slide under the effect of driving means between a retracted position inside the sleeve and an extended position in which it projects from the upper bearing face of the sleeve by an end portion forming an indexing pin, a jaw clamping the workpiece on the upper bearing surface of the sleeve, mounted movably on the centering pin and means for controlling the jaw comprising a slide mounted in an axial bore of the piston and having a cam end. These control means are constituted by a slider mounted in an axial bore of the piston for sliding under the effect of the drive means between a first position in which it ensures the locking of the jaw in its active position by means of a part active cam member pivotally driving the clamping jaws to said operative position and a second position in which it releases the lock of said jaw by controlling the pivoting of the clamping jaws to the inactive position.

The drive means comprise inter alia a first return spring disposed between the piston and the sleeve to return the piston towards its extended position and a second return spring disposed between the sleeve and the slide to return the slide to its unlocked position. of the jaw.

The axial displacements of the piston inside the sleeve and the slider in the piston are controlled by a jack. A major disadvantage of this type of device is that, in the event of an incident, for example during an air failure, the cylinder no longer operates and then the second return spring blocks the device in the clamping position. Thus, in the clamping position, it is then not possible to release the part thus held.

In addition, this structure is relatively complicated and wear, particularly spring expansion, can cause problems of correct positioning of the jaws over time.

The application WO-A-98/28110 filed by the applicant describes a centering and clamping tool comprising a pilot member, clamping members and means for driving the clamping members simultaneously causing said members to pivot and translate. of Tightening. These drive means consist in particular of two levers forming a deformable axis about their connecting axis under the effect of a jack.

Such a centering and clamping tool makes it possible to correctly position the clamping members on the part to be fixed during the centering step carried out by placing the pilot member through the through and fitted passage of the workpiece. and the pivoting drive of the clamping members allows the protruding drive of said clamping members out of the pilot member and their lowering on either side of the pilot member to bear against the workpiece to be fixed. position, the drive in translation and in simultaneous pivoting of said clamping members causing the clamping of the workpiece to be fixed in position against the end of the housing, on the upper face of said support casing. Thus, it ensures a perfect deployment clamping members protruding from the pilot member and a plurality of clamping positions is obtained on the workpiece to be fixed.

However, all these centering and clamping tools also have a disadvantage in that they do not allow to work with parts of different thicknesses.

Thus, on the same work station, the clamping tools are calibrated to treat a workpiece of a given thickness and can not treat a workpiece of another thickness without incurring, in the event of a different thickness, a risk of punching the workpiece. the treated room. It is then necessary to change the centering tool and clamping by another adapted to treat this new thickness.

In the French patent application No. 9907749, the applicant has proposed a centering and clamping tool which comprises a fixing support comprising a support piece provided with a chimney in which is mounted the pilot member, the pilot member being projecting at the free end constituting the bearing face of the workpiece, while the body of the tool is clamped against a face of the support opposite to the bearing face. When tightening the tool, it is possible to insert a removable wedge which makes it possible to vary the gap between the bearing face and the clamping means deployed outside the pilot member. It is thus possible to treat, by simple change of the wedge, several pieces of different thicknesses.

Such a tool is advantageous because it allows not to change tools to treat parts of different thicknesses but it still requires manipulation to adapt the tool to the new part.

None of these centering and clamping tools offers a simple adaptation without external manipulation for the treatment of parts of different thickness, especially during the same phase of work at the same workstation.

In order to overcome this drawback, the present invention proposes a centering and clamping tool that can process parts of different thicknesses without requiring the tool to be changed or manipulated to adapt it to the thickness of the tool. new room.

For this purpose, the subject of the invention is a tool for centering and clamping at least one workpiece to be fixed in position and having a through passage and adjusted for said tool, of the type preferably comprising a pilot member brought to the end of a housing having an upper face forming a support for said part and clamping members, further comprising means for driving the clamping members between a centering position in which the clamping members are removed at inside the pilot member and a plurality of clamping positions in which the clamping members are projecting outside the pilot member and resting on the workpiece, the clamping members being constituted by two levers articulated about a median axis to form a deformable X, each lever having a first free end coming into bearing on the part to be fixed, their second end being connected to the drive means, characterized in that the drive means consist of two connecting rods, one end of which is articulated on said second end of the levers by means of a hinge pin, the connecting rods being disposed on either side of a cam having on each side two diverging cam profiles substantially forming a rhombus and drivable in linear translation under the effect of a jack, each rod having a first stud supported and movable along a wall of a cassette enclosing the assembly and parallel to the axis of sliding of the cylinder, two other studs being r abutably supported along a cam profile while the link pin of the connecting rod on the lever is supported and movable along said wall of the cassette and is housed in a transverse groove, preferably perpendicular to said wall to allow the approximation and spacing of the levers in a plurality of positions between two extreme positions, the sliding drive of the cam by the cylinder causing a drive in translation of the rods and clamping members until the hinge pins are respectively opposite a groove so as to cause a pivoting drive of said clamping members by sliding the hinge pins in the respective groove.

Thus, advantageously, in the rest position of the jack, the clamping members are retracted into the pilot member, which allows easy introduction of the tool into the through passage of the workpiece.

When deploying the rod of the cylinder, the cam moves towards the pilot member and some pads of each rod slide along the wall of the cassette while the others remain in support on the cam profiles.

Indeed, these divergent cam profiles tend to rotate the connecting rods but they are supported along a wall of the cassette parallel to the axis of sliding of the cylinder by a stud and, therefore, the pivotal movement induced by the cam profiles against the pads in abutment is converted into a translational movement of said rods.

The hinge pins of the rods on the clamping members bearing against the same wall of the cassette also slide along this wall and drive in translation the clamping members to the groove where the hinge pins can be housed .

The cam continues its linear movement under the effect of the jack and the pivoting of the studs against the cam profiles then causes the displacement of the articulation pins in the groove, which causes the spacing of the clamping members until these, deployed on both sides of the pilot body, bear against the part to fix.

To release a part, retracts the rod of the cylinder and all the movements described above is carried out in the opposite direction, bringing the clamping members in the retracted position in the pilot member.

Advantageously, when the parts to be treated have a different thickness, the drive means cease their action as soon as the clamping members are resting on the part while ensuring a certain tightening, the force of the jack being calibrated so that it does not oppose the mechanical blocking of the clamping members coming into support on the part or, preferably, under the control of detection means.

In the centering position, the clamping members are erased in the pilot member which has a slot for this purpose. This slot communicates the inside of the clamping and centering tool with the outside. In particular, it makes accessible the clamping members and the drive means.

Thus, a tool according to the invention makes it possible to treat parts of different thicknesses at the same station and without manipulation or adjustment of said tool.

According to a preferred embodiment of the invention, the pilot member is partially retractable and the driving means of said pilot member between its retracted position and its protruding position are the same as the driving means of the clamping members. Thus, the pilot member is connected to at least one connecting rod by means of one of its studs resting on a cam profile so that, during the actuating stroke of the cam by the jack , the pilot tool is driven in linear translation with the clamping members to its centering position of the workpiece. Then, the clamping members unfold and come close behind the fallen edge of the through passage of the part to fix if there is one.

A pneumatic cylinder, a hydraulic cylinder or an electric cylinder are used as well.

• les figures 1a et 1b représentent respectivement une vue en perspective de l'outil selon l'invention et une vue en perspective de l'outil dans laquelle certaines parties ont été enlevées ;
• la figure 2 représente une vue en coupe longitudinale de l'outil selon l'invention ;
• la figure 3 représente une vue en coupe longitudinale de l'outil selon la figure 2 en position de serrage d'une pièce ;
• la figure 4 représente une vue en coupe longitudinale de l'outil selon la figure 3 en position de serrage d'une pièce-d'épaisseur différente ;
• la figure 5 représente une vue en perspective d'une chape de l'outil selon l'invention et
• les figures 6a et 6b représentent respectivement une vue en perspective éclatée de l'outil selon la figure 2 muni de l'organe pilote ainsi qu'une vue en perspective dudit organe pilote.

An embodiment of the invention will now be described in more detail with reference to the appended drawing in which:

• FIGS. 1a and 1b respectively represent a perspective view of the tool according to the invention and a view in perspective of the tool in which some parts were removed;
• Figure 2 shows a longitudinal sectional view of the tool according to the invention;
• Figure 3 shows a longitudinal sectional view of the tool according to Figure 2 in the clamping position of a workpiece;
• Figure 4 shows a longitudinal sectional view of the tool according to Figure 3 in the clamping position of a piece-of different thickness;
• FIG. 5 represents a perspective view of a clevis of the tool according to the invention and
• Figures 6a and 6b respectively show an exploded perspective view of the tool according to Figure 2 provided with the pilot member and a perspective view of said pilot member.

The centering and clamping tool 1 according to the invention comprises a casing 2 enclosing a pneumatic supply device for the drive means comprising a distributor 3 and a distribution block 4 connected to a jack 5 of the drive means .

On this housing 2 is mounted a body 6 from which protrude the pilot member 7 and the clamping members 8 housed in a slot 7a of said pilot member 7.

Around the pilot member and on the body 6 is mounted a flange 9 forming a support for the workpiece.

The body 6 contains a cassette 10 consisting of two identical half-housings 11 between which are housed the drive means of the clamping members 8.

A face 2a of the casing 2 serves to fix said tool 1 in a standard manner. The tool also comprises means 13 for detecting the state of the engaged tool or uncommitted tool.

Between the half-housings 11 forming the cassette 10 are housed the drive means which consist of a cam 14 and two connecting rods 15.

The cam 14 is connected to the jack 5 by means of a yoke 16.

Drug. 14 has on each side two diverging cam profiles 14a and 14b, said cam 14 having substantially the shape of a rhombus.

The rods 15 are placed on either side of the cam 14 and each have two studs 15a and 15b respectively bearing against the profile 14a and the profile 14b of the cam 14.

Each connecting rod 15 further comprises a stud 15c bearing against a linear wall 10 'of the cassette 10 and more precisely against a wall of a half-casing 11 and against a wall of the other half-casing 11. This wall 10 linear is parallel to the sliding axis xx 'of the cylinder rod 5.

The end of the rods 15 opposite the end of the side of the yoke 16 is hinged to the clamping members 8 by means of a hinge pin 17.

The clamping members are constituted by two levers 8 articulated around a median axis 8c to form a deformable X, each lever 8 having a hook-shaped first end 8a bearing on the piece to be fixed P and the second end 8b being connected to a lever 15. The levers 8 are preferably bent around their articulation axis 8c. The hook shape of the end 8a of the levers 8 allows easy crossing of a flanged sheet metal section at the through passage of the piece P.

At the end of the cassette 10 towards the outside of the tool 1 are provided, between the two half-housings 11, two grooves 18 transverse and perpendicular to the walls 10 'of the cassette 10.

During operation of the tool 1, the pilot member 7 is positioned opposite a through passage 19 formed in the part to be fixed P. For the sake of clarity, the pilot member 7 has not been shown. in Figures 2, 3 and 4.

The pilot member 7 is partially retractable and is drivable between its retracted position and its centering position by the driving means of the clamping members. Thus, the pilot member 7 is connected to the connecting rods 15 by means of the studs 15b engaged in notches 7a of said pilot member 7 (see FIGS. 6a and 6b).

Once, the pilot member 7 positioned relative to the workpiece P, it can actuate the drive means of the clamping members 8 which are retracted into said pilot member 7. For this purpose, the rod of the actuator 5 is deployed. in order to drive the cam 14 in the direction A towards the piece P.

The cam 14 tends to slide against the studs 15a and 15b of the rods 15 which bear respectively on these diverging cam profiles 14a and 14b. During this movement, the studs 15b are pushed towards the outside of the cassette 10 while the studs 15a are brought inwards, which induces a pivoting movement of each rod 15. However, the studs 15c of each link 15 and the hinge pins 17 resting against the walls 10 'of the cassette 10, transform the pivoting translation of the rods 15 with the cam 14.

Thus drives in translation the clamping members 8 but also the pilot member 7 engaged on the pads 15b which allows the centering of the piece P.

When the hinge pins 17 reach respectively a groove 18, each link 15 then pivots under the effect of the cam 14, the cam profiles 14a and 14b moving against the pads 15a and 15b, and the pin articulation 17 guided in the groove 18 causes the spacing of the ends 8b of the clamping members 8 and the deformation of the X to lower the ends 8a on the piece P until they bear on the piece P .

As can be seen in Figures 3 and 4, the stroke of the cylinder rod 5 is different depending on the thickness of the part P, the stroke of the cylinder 5 being stopped as soon as the ends 8a rest on the workpiece P.

The stroke in the groove 18 is adjustable so as to determine the two extreme clamping positions of the tool 1 between which is defined a plurality of clamping position.

The adjustment means consist of a screw 20 engaged in said groove 18 from outside the cassette 10 and therefore easily adjustable.

When the actuator 5 is actuated in the opposite direction according to the arrow B to erase the clamping members 8 in the pilot member 7, the cam 14 pivots the levers 8 and the rods 15 until the pins articulation 17 is disengaged from the groove 18, and then moves the rods 15 and the 8 translation clamping in the direction of the arrow B and thus brings the pilot member 7 in the retracted position. Preferably, the cam 14 has, on each side, between the two cam profiles 14a and 14b a redent 14c which abuts against the stud 15a on the side of the jack 5.

Preferably, the tool 1 according to the invention comprises means making it possible to ensure the safety of said tool even in the event of a break in the supply of the jack 5.

Thus, the yoke 16 is connected to the cassette 10 by means of two bistable springs 21, each spring 21 being pivotally mounted on said cassette 10 and on the yoke 16 and, in the clamping position and in the retracted position of the clamping members 8, the springs 21 are in a stable position (see Figures 3, 4 and 5) and, during actuation of the cylinder, are in the non-stable position.

Thus, the displacement drive of the yoke 16 causes the springs 21 to pivot relative to their point of attachment in the cassette 10, which leads to a compression of the springs 21.

In the example shown, the springs 21 are constituted by corrugated blades which provides a sufficient return force with a small footprint.

Therefore, if in the clamping position, the pneumatic supply is cut off, the springs 21 in a stable position hold the yoke 16 carrying the cam 14 in the clamping position. It is the same in the rest position of the tool 1.

The jack 5 is pneumatic, or hydraulic or electric.

Claims (15)

1. Tool (1) for centring and clamping at least one part (P) to be fixed in position and comprising a through passage (19) adjusted for the said tool (1), of the type comprising, preferably, a control member (7) borne at the end of a housing (2) having an upper surface forming a support for the said part (P) and clamping members (8), additionally comprising drive means (5, 14, 15) for driving the clamping members (8) between a centring position in which the clamping members are withdrawn inside the control member (7) and a plurality of clamping positions in which the clamping members (8) project outside the control member (7) and are supported on the part (P), the clamping members consisting of two levers (8) articulated about a central pin (8c) so as to form a deformable X shape, each lever (8) having a first free end (8a) coming into contact with the part (P) is to be fixed, their second end (8b) being connected to the drive means (5, 14, 15), characterized in that the drive means consist of two links (15) having an end which is articulated on the said second end (8b) of the levers (8) by way of a pivot spindle (17), the links (15) being arranged on either side of a cam (14) which is provided on each side with two divergent cam profiles (14a, 14b) forming an approximate diamond-shape and which is able to be driven with a linear translational movement under the effect of an actuator (5), each link (15) comprising a first peg (15c) which is supported along and can move along a wall (10') of a cassette (10) containing the said drive means and running parallel to the sliding axis of the actuator (5), two other pegs (15a, 15b) being respectively supported along a cam profile (14a, 14b), while the pivot spindle (17) for articulating the link (15) on the lever (8) is supported along and can be moved along the said wall (10') of the cassette (10) and can be housed in a transverse groove (18), which is preferably perpendicular to the said wall (10'), so as to allow the levers (8) to come together and move apart in a plurality of positions between two end positions, the sliding movement of the cam (14) produced by the actuator (5) causing a translational movement of the links (15) and of the clamping members (8) until the pivot spindles (17) are respectively in register with a groove (18) in such a way as to cause a pivoting movement of the said clamping members (8) as a result of the pivot spindles (17) sliding into the respective groove (18).
2. Tool according to Claim 1, characterized in that the cam (14) is mounted on the actuator (5) by way of a clevis (16).
3. Tool (1) according to either of Claims 1 and 2, characterized in that the cam (14) comprises a step (14c) between the two cam profiles (14a, 14b), forming a stop for the peg (15a) arranged towards the actuator (5).
4. Tool (1) according to one of Claims 1 to 3, characterized in that the depth of the groove (18) is adjustable.
5. Tool (1) according to Claim 4, characterized in that the adjusting member consists of a screw (20).
6. Tool (1) according to Claim 5, characterized in that the levers (8) are bent around their pivot pin (8c) and their end (8a) which comes into contact with the part (P) has the shape of a hook.
7. Tool (1) according to one of Claims 1 to 6, characterized in that the clevis (16) is connected to the cassette (10) by way of two bistable springs (21), each spring (21) being pivotally mounted on the said cassette and on the clevis (16) and occupying a stable position when the tool is in the rest position and when the tool is in the clamping position.
8. Tool (1) according to Claim 7, characterized in that the springs (21) consist of corrugated leaves.
9. Tool (1) according to one of Claims 1 to 8, characterized in that the control member (7) is partially retractable and the drive means for driving the said control member (7) between its retracted position and its projecting position are the same as the drive means for driving the clamping members (8).
10. Tool (1) according to Claim 9, characterized in that the control member (7) is in connection with at least one link (15) by way of one (15b) of its pegs supported on a cam profile (14b), in such a way that, during the actuating travel of the cam (14) produced by the actuator (5), the control member (7) is driven in a linear translational movement with the clamping members (8) towards its position for centring the part (P).
11. Tool (1) according to one of Claims 1 to 8, characterized in that the said control member (7) is fixed in terms of projection with respect to the said cassette (10).
12. Tool (1) according to one of Claims 1 to 11, characterized in that it comprises detection means (13) for detecting the engaged or non-engaged position of the said tool (1).
13. Tool (1) according to one of Claims 1 to 12, characterized in that the actuator (5) is pneumatic.
14. Tool (1) according to one of Claims 1 to 12, characterized in that the actuator (5) is hydraulic.
15. Tool (1) according to one of Claims 1 to 12, characterized in that the actuator (5) is electric.

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