EP0308333A1 - Clamping assembly for work pieces - Google Patents

Abstract

The invention relates to a clamping assembly for fastening workpieces, of the type comprising clips provided with elastically deformable fingers pressing against the lateral edges of the workpiece, this assembly comprising a plate (1) provided on one of its faces with parallel grooves (5) of the T-shaped type, in which grooves slide sliding blocks (3) having a heel of corresponding cross-section provided with a locking member. …<??>This assembly is characterised in that clips (16) with a cam (17) bearing on one of the edges (20) of the workpiece (P) are opposite other clips/stops (2) bearing on the opposite edge, the plate furthermore having fixing means (4) for immobilising it on the table of a machine tool or in the jaws of a vice. …<??>This type of clamping is suitable for the multiple gripping of workpieces with parallel or non-parallel edges. …<IMAGE>…

Description

The invention relates to a clamping assembly intended for the serial fixing of workpieces on the same plate which can be immobilized either in the jaws of a vice or on the table of a machine tool.

Machine tool clamping devices are already known which are intended to immobilize a workpiece facing a tool which may be a drill, a milling cutter, a planing tool or the like. These devices are for example made up (French patent 2,427,170 belonging to the applicant) of spring steel anchoring elements produced in the form of studs comprising in particular three fingers, two of them, of small thickness being elastically deformable, while that the third thickest is set back to form a stop. The application of these studs on the side face of a workpiece is here caused by a horizontal thrust exerted by the movement of a screw. These devices are very effective in terms of clamping but have the major drawback of being bulky and of being ill-suited to the multiple fixing of workpieces to an available surface.

We also know (DE 3237 705 of October 12, 1982) a clamping assembly formed of a plate whose upper face has T-section grooves in which slide clamping elements comprising jaws capable of moving obliquely towards the side of the workpiece by the play of a ramp and by the action of a clamping screw. The effectiveness of such an anchoring system is random since the clamping pressure of the jaw on the sides of the workpiece is essentially a function of the tightening rate of the screw and therefore of the reliability of the manipulator. In addition, the oblique displacement of the jaw results in a progressive friction of its operational face on the side of the workpiece risking, therefore, creating damage or deterioration of said part.

The invention aims to remedy these drawbacks and relates to a clamping assembly using the principle of the plate referred to in German patent DE 32 37 705 but in combination with crampons with elastic deformation of the type described in patent 2 427 170 but designed to operate by eccentric and no longer by horizontal push screw.

An object of the invention therefore consists in being able to clamp "in a jiffy" one or more parts to be machined using clamping fingers exerting a cramping on the lateral edges of the part in order to completely release its upper face. called to be machined.

Another object of the invention is to provide a clamping device which is highly efficient and above all, of good reliability in order to avoid accidents due to loosening of the part which could then behave like a real projectile. .

The invention therefore relates to a clamping assembly for fixing a workpiece of the type comprising crampons provided with elastically deformable fingers bending over the lateral edges of the workpiece, this assembly comprising a plate provided on one of its T-shaped parallel groove faces, in which slides slide having a heel of corresponding section provided with a locking member, characterized by eccentric crampons bearing on one of the edges of the workpiece in opposition to other crampons-abutments resting on the opposite edge, the plate furthermore having fixing means for its immobilization on the table of a machine tool or in the jaws of a vice.

According to a preferred embodiment, each slide consists of a base with inverted T section, sliding in the correspondingly shaped grooves of the plate, this base being associated on the one hand with a head also in T section, independent of the base but joined to the heel thereof by a locking screw, on the other hand to a trident crampon coupled to this same heel by an axis with an eccentric head.

According to another characteristic of the invention, the stopper studs are aligned with the reference plane formed by the edge of the plate, the immobilization of these studs being ensured by two screws screwing into threaded orifices of the plate.

According to one embodiment, the fixing means of the plate consist of lower studs housed in recesses formed under the bearing face of the plate, these studs comprising an annular shoulder for receiving the head of a fixing screw in taken in a threaded hole in the plate.

• - la figure 1 est une vue en perspective d'un ensemble de bridage constitué d'une platine pour la fixation en série de pièces à usiner;
• - la figure 2 est une vue en perspective de cette même platine immobilisée dans les mâchoires d'un étau ou d'une presse;
• - la figure 3 est une vue en perspective illustrant l'immobilisation de deux platines sur le même plateau d'une table de machine-outil;
• - la figure 4 est une vue en perspective d'une platine immobilisée dans les rainures à section en T d'une table de machine-outil;
• - la figure 5 est une vue en perspective d'un coulisseau de verrouillage;
• - la figure 6 est une vue en perspective d'un des crampons-butées;
• - la figure 7 est une vue en perspective d'un coulisseau dont le crampon est réglable angulairement pour pouvoir être adapté aux pièces à bords non parallèles;
• - la figure 8 est une vue en perspective d'un crampon de verrouillage associé à un fourreau tel que celui illustré en figure 9;
• - la figure 10 est une vue en perspective d'un crampon de verrouillage associé à une réhausse telle que visible en figure 11;
• - les figures 12 et 13 sont des vues illustrant respectivement la fixation de la platine sur une table de machine-outil pourvue soit d'orifices taraudés, soit de rainures en T;
• - la figure 14 est une vue en plan montrant l'immobilisation de deux ou plusieurs platines sur une table de machine-outil;
• - la figure 15 est une vue en perspective éclatée d'une bride et de son support de bride;
• - la figure 16 est une vue de dessous des crampons inférieurs de fixation de la platine;
• - la figure 17 est une vue en coupe montrant la position du crampon inférieur sous la face d'appui de la platine;
• - la figure 18 est une vue en plan illustrant le détail des doigts du crampon inférieur;
• - les figures de 19 à 22 illustrant en perspective des formes de réalisation différentes des crampons;
• - la figure 23 montre un crampon de verrouillage associé au fourreau illustré en figure 9;
• - la figure 24 est une vue de dessus du crampon de la figure 23.
• - la figure 25 représente une vue éclatée d'un coulisseau du type réhaussé.

Other characteristics will emerge from the description and the appended drawings in which:

• - Figure 1 is a perspective view of a clamping assembly consisting of a plate for serial fixing of workpieces;
• - Figure 2 is a perspective view of the same plate immobilized in the jaws of a vice or a press;
• - Figure 3 is a perspective view illustrating the immobilization of two plates on the same plate of a machine tool table;
• - Figure 4 is a perspective view of a plate immobilized in the T-section grooves of a machine tool table;
• - Figure 5 is a perspective view of a locking slide;
• - Figure 6 is a perspective view of one of the crampons-stops;
• - Figure 7 is a perspective view of a slide whose clamp is angularly adjustable to be able to be adapted to parts with non-parallel edges;
• - Figure 8 is a perspective view of a locking stud associated with a sheath such as that illustrated in Figure 9;
• - Figure 10 is a perspective view of a locking clamp associated with an extension as visible in Figure 11;
• - Figures 12 and 13 are views respectively illustrating the fixing of the plate on a machine tool table provided with either threaded holes, or T-slots;
• - Figure 14 is a plan view showing the immobilization of two or more plates on a machine tool table;
• - Figure 15 is an exploded perspective view of a flange and its flange support;
• - Figure 16 is a bottom view of the lower clamps for fixing the plate;
• - Figure 17 is a sectional view showing the position of the lower clamp under the bearing face of the plate;
• - Figure 18 is a plan view illustrating the detail of the fingers of the lower clamp;
• - Figures 19 to 22 illustrating in perspective different embodiments of the studs;
• - Figure 23 shows a locking stud associated with the sheath illustrated in Figure 9;
• - Figure 24 is a top view of the stud of Figure 23.
• - Figure 25 shows an exploded view of a slide of the raised type.

The clamping assembly according to the invention consists essentially of four distinct means: a plate 1, crampons-stops 2, locking slides 3 and members 4 for fixing the plate on the table of a machine -tool or in the jaws of a vice or a press.

In detail, the plate is in the form of a parallelepipedal block provided with parallel grooves 5 with T-section whose dimensions are comparable to those of the grooves of a machine tool table. The two opposite sides of the plate, parallel to these grooves, have rectilinear grooves 6 and 7 which will be used for clamping it on a machine tool table as visible, for example, in Figures 3 and 4. The other two sides 8 and 9 of the plate are strictly perpendicular to the grooved sides 6 and 7 in order to constitute reference planes, in particular for the crampons-stops 2.

We will examine below the detail of the crampons-stops 2 and of the slides 3 used for the lateral clamping of the workpieces P.

The studs visible in FIG. 1, but the detail of which appears better in FIG. 6, are formed of a kind of fixing flange 2₁ provided with two holes 10 for the passage of screws, extended on one of its longitudinal sides by three fingers, two of which are elastically deformable, while the third is rigid to constitute a limit stop. The deformable fingers 2₂ are located on either side of the middle finger 2₃ which is thicker than the other two and slightly set back, so that it comes into lateral support on the part P to be machined after deformation elastic (bending) of the outer fingers 2₂. These crampons-stops are fixed on the upper face of the plate 1 by threaded stud screws 11 (FIG. 1) more designed in the technique of the invention under the terminology "vis-locating", the front edges 2₂, 2₃ of these spikes being aligned with the edge 9 of the plate which thus constitutes a reference plane, the precise alignment of the front edges 2₂, 2₃, of a spike-stop relative to this plane being ensured by the combination of a parallelism exact between said plane and the straight line passing through the respective longitudinal axes of the two fixing screws 11 and by a rigorous parallelism between said straight line and the front edges 2₂, 2₃, of the clamp-stop, so that the clamping force will bear uniformly distributed on these front edges 2₂, 2₃, of the crampon-stop therefore by repercussion on the two screws 11 holding it.

The slides, visible in FIG. 1, but the detail of which appears better in FIG. 5, consist of a base 12 with inverted T section, the dimensions of which are complementary to those of the grooves 5 of the plate 1. This base serves as a support to a cleat 13 also with a T-shaped section traversed right through by a circular orifice 14 in which is housed a fixing screw 15 whose lower end is screwed into the base 12. This slide 3 also comprises a locking crampon 16 similar to the crampons-stops 2, that is to say of the trident type, two of the outer fingers 16₁ of which are thin and therefore elastically deformable while the middle finger 16₂ is thicker and slightly recessed. In addition, and this is an essential feature of the invention, this stud 16 is provided with an annular shoulder in which the eccentric head 17 of an axis 18 is housed passing through the base 12 from top to bottom, and being located in translation by a circlip (not shown). So, the rotation of this axis, by introduction of an Allen key in the blind hole with hexagon socket 18, allows a forward movement of the stud 16, that is to say in the direction of the part P if the reference is made to FIG. 1. The adjustment stroke is displayed by a reference 19 provided on the eccentric head of the locking pin. Thus, there is, as the rotation of this axis 18, a thrust forwards of the crampon 16 which acts in opposition to the crampons-stops 2, fixed in position and aligned on the edge of the plate. It is therefore the rotation of this eccentric head 19 which clamps the workpiece P, the elastically deformable fingers 16₁ coming into primary contact with the edge 20 of the workpiece P (Figure 1) until that, after elastic deformation, the middle finger 16₂ in turn comes into contact with said workpiece.

If the workpiece does not have strictly parallel edges, it is then possible to use another type of slider such as that visible in FIG. 7 and replace it with the crampon-stopper 2. In this case, the crampon 21 provided on this slide is angularly movable around the axis 22 which, unlike the clamp 16 of Figure 5, is not eccentric. Thus, the crampon can pivot, position itself angularly to adapt to the inclination of the edge of the workpiece, and be locked in this position. In this event, this slide illustrated in FIG. 7 will work in opposition to the slide illustrated in FIG. 5.

The T-shaped grooves 5 of the plate 1 obey standardization standards. The height of the T-shaped groove 5 can have dimensional variations of several millimeters according to the standards for standardizing machine tool table grooves, according to ISO 299 or DIN 650 standards. In this case, slides of the raised type neglecting these variants of dimensions in height. As shown in FIG. 25, the variable height of the T-shaped groove is referenced X. These slides of the raised type include a base 12 with inverted T-section sliding in the groove 5, the dimensions of which are complementary to those of the groove 5. This base serves as a support for a cleat 13 also with a T-section, the cleat 13 being fixed on the base 12 by means of a fixing screw 15 and by a centering pin 41 partially housed in the base 12 and partly in the bracket 13. The axis of the fixing screw 15 and the axis of the centering pin 41 are located in alignment with the longitudinal axis of the base 12. The bracket 13 has one end forming projecting from the base 12 in its longitudinal direction. A stud 16 is fixed to this projecting end of the cleat 13, so that said stud 16 overhangs the base 12. The stud 16 can of course be of the eccentric type as described in FIG. 5 or of the non-eccentric type as described in FIG. 7. Thus, due to this design, it is easy to compensate for the variations in height of the T-groove by adjusting the positioning of the cleat 13 relative to the base 12 by means of the fixing screw 15.

We will in all cases be in the presence of two crampons-stops 2 or 21 intended to immobilize the part with respect to a reference plane and locking crampons 16 which they perform the lateral clamping of the part. It is also possible to replace the slide 3 with locking studs such as those illustrated in FIG. 8. Here, the studs comparable to that used on the slide of FIG. 5 obviously includes an axis with an eccentric head 23 ensuring the clamping of the part to be machine. This crampon is used in association with a sheath 24 (FIG. 9) which is housed as visible in FIG. 23 in an orifice 25 in the plate 1. It is also possible, if one wishes to obtain a clamping at levels different, use sleeves 26 with shoulder 27 in which is housed the axis of the eccentric head 23 as visible in FIG. 10.

To adapt to these different levels of clamping, one can use, as shown in Figures 19 and 20, crampons-stops having the general shape of a Z. In this case, the fixing face 2 de of the crampons 2 is at a different level from the 2₂ and 2₃ clamping fingers which are no longer in the plane of the flange but raised by a recess 28.

Of course, the fingers of the crampons-stops 2 can have different shapes and dimensions as shown in FIG. 21 and 22 or precisely it is observed that the fingers 2₂ and 2₃ have different dimensions and morphologies. With regard to FIG. 22, it is here the outer fingers 2₂ which are rigid and set back from the middle finger 2₃ which, on the other hand, is elastically deformable, unlike the example chosen in FIG. 21. In this case the contact faces of the rigid stops (constituted by the middle finger 16₂ of a trident crampon 16 with eccentric in opposition with the two outer fingers 2₂ of a crampon-stop 2) define a triangular support on the workpiece (held between those -ci), this geometric figure being well known as being that which is mechanically the most stable.

Thus, the fixing of the workpieces P on the plate 1 is obtained, as indicated above, by on the one hand, studs-stops 2, and on the other hand, locking slides 3. Thus, to carry out the clamping P parts, as shown in Figure 1, we proceed in the first place, the fixing of the crampons-stops 2, taking care to align them on the reference plane that constitutes the rear face 9 of the plate. At this stage, the pieces P are brought into abutment on the projecting fingers of the studs-stops 2 and then introduced the sliders 3 into the T-shaped grooves of the plate, having taken care to unscrew the screws 14 beforehand (FIG. 5). When the fingers 16₁ of the locking studs 16 are in turn in contact with the workpiece, the slide is immobilized in the groove 5 of the plate by rotation of the screw 14 which by screwing into the base 12 of the slide has a tendency to attract it upwards until its wings 12₁ come to bear against the corresponding returns 5₁ of the grooves 5. At this stage, the slider is immobilized and, it only remains to clamp the workpiece, which corresponds in a way to a fine adjustment since already the studs 2 and 16 in opposition are in contact with the two blanks 20 of the workpiece P. This clamping is obtained by simple rotation of the eccentric head 17 of the axis 18 which, as indicated above, pushes the clamp 16 in the direction of the workpiece, thereby causing firm and progressive pressing of the clamping fingers 16₁ on the blanks of the workpiece until they these are erased by bending to allow the finger m édian 16₂ to come in turn to a stop on the blank of the room. At this stage, the part 20 is rigorously immobilized by lateral clamping coming from the combined action of the fingers of the locking studs 2 and the fingers of the locking studs 16. The action would obviously be identical if the eccentric studs were used illustrated in figures 8 and 10 with or sand raised.

As indicated previously, the series of crampons as visible in FIG. 1 can be used for the clamping of several pieces assembled in series, or even for the immobilization of a single piece of grant format.

When the where the parts have been immobilized by lateral clamping, it is then necessary to fix the plate in order to obviously avoid its displacement or its rotation under the force caused by the torque of the tool. To do this, one can use several means depending on whether the machine carries a table with a T-groove or with threaded orifices, or even whether it is the jaws of a vice or a press.

These three methods of attachment are described below.

As regards immobilizing the plate on a grooved table, as illustrated in FIG. 4, we use as visible in FIG. 13, flanges and flange holders respectively 28 and 29 engaged laterally with the plate 1. In fact, this plate is provided as shown in Figure 1, lateral grooves 6 and 7 with parallel edges serving as a support seat for one of the edges of the flange 28, the opposite edge resting, meanwhile, on a shoulder 29 un of the flange support 29. A fixing stud 30, comparable to a nut, and having a thread with differential pitch, ensures the clamping of the plate by screwing in a cleat 31 with T-section housed inside the grooves 5 of the machine 1. Of course, the dimensions of this cleat 31 are quite comparable to those of the groove 5 so that one obtains by rotation of the stud 30 a support of the two wings of the cleat on the corresponding edges of the groove. The stud 30 has a blind hole 32 with a hexagon socket allowing its rotation.

According to another embodiment, the plate can also be immobilized according to the principle described above, with the difference that the stud 30 is not screwed into a cleat 31 but directly into a threaded orifice 33 as visible in FIG. 12.

Of course, it is possible to clamp several plates 1 (FIG. 14) by the set of flanges 28 and studs 30 penetrating indifferently into brackets 31 or rough holes 33. In the example visible in FIG. 14, it is the fixing by holes that has been retained.

The detail of the flange 28 associated with its flange support 29 is clearly illustrated in FIG. 15 where the fixing screws 34 are seen serving for the coupling of these two parts. These screws 34 pass through the orifices 35 provided in the upper part of the flange support and are screwed into the thickness of the flange 28 provided for this purpose with tapped orifices 36.

If the plate 1 is immobilized in the jaws 37 of a mechanical or pneumatic vice (FIG. 2), use will be made to obtain a rigorous clamping of the plate 1 to the lower studs 4 (FIG. 1), the detail of which is particularly visible. in Figures 16 to 18. These studs 4 are fixed under the bearing face 1₁ of the plate 1 in countersunk recesses 38, the fixing being obtained by a clamping screw 39 whose head 39₁ is received in a shoulder annular 4 formed in the spike 4. It is observed that these spikes are provided with two teeth 4₂, elastically deformable (therefore of small thickness), the front end 4₃ of these fingers projecting slightly on the front face 8 of the plate 1 ( figure 16). It should also be noted that these fingers are bent upwards, that is to say in the direction of the upper face of the plate so that one obtains, by feedback, when tightening the jaws 37 of the vice, a bending of the end of the fingers down, that is to say that a self-application is obtained.

Claims (19)

1) Clamping assembly for fixing workpieces of the type comprising crampons, this assembly comprising a plate (1) provided on one of its faces with parallel grooves (5) of T-type, in which slides slide (3) having a heel of corresponding section provided with a blocking member, characterized by cleats (16) provided with elastically deformable fingers, these being moved in translation by an eccentric and bearing on the edge (20) of the workpiece (P) in opposition to other elastically deformable studs (2) bearing on the opposite edge of the workpiece, the plate (1) having fixing means (4, 28, 29 , 30) for its immobilization on the table of a machine tool or in the jaws of a vice. 2) clamping assembly according to claim 1, characterized in that each slide (3) consists of a base (12) with inverted T section, sliding in the grooves (5), of corresponding shapes of the plate (1 ), this base being associated on the one hand with a head (13) also in T section, independent of the base but joined to the heel (12) thereof by a locking screw (14), on the other hand to a trident crampon (16) coupled to this same base by an axis (18) with eccentric head (17). 3) Clamping assembly according to claim 2, characterized in that the triden clamp (16) has two outer fingers (16₁) slightly projecting and of less thickness than the middle finger (16₂) which is slightly set back from the other two to form a stop. 4) clamping assembly according to claim 2, characterized in that the triden clamp (16) has an annular shoulder in which the head pivots eccentric (17) of the clamping axis (18), the latter comprising a mark (19) for positioning the clamping stroke. 5) clamping assembly according to claim 2, characterized in that the heel of the base (12) is provided with a threaded orifice in which the locking screw (14) of the T-section head (13) is screwed. 6) Clamping assembly according to claim 4, characterized in that the clamping axis (18) is immobilized at its lower end by a circlip set back from the underside of the heel (12) of the slide. 7) clamping assembly according to claim 1, characterized in that the stopper cleats (2) have three fingers, two of which (2₂) are elastically deformable and are located on either side of the thicker middle finger (2₃) and slightly behind the outside fingers. 8) clamping assembly according to claim 7, characterized in that the front edges (2₂, 2₃) of the studs-stops (2) are aligned with the reference plane formed by the edge (9) of the plate (1), the immobilization of these studs being ensured by two threaded nipple screws (11) (screw-locating) screwing into threaded orifices of the plate (1), the precise alignment of the front edges (2₂, 2₃) of a crampon-stop relative to this plane being ensured by the combination of an exact parallelism between said plane and the straight line passing through the respective longitudinal axes of the two fixing screws (11) and by a rigorous parallelism between said straight line and the front edges (2₂, 2₃) of the crampon-stop. 9) Clamping assembly according to claim 1, characterized in that the studs have three fingers of unequal width, the two outer fingers (2₂) being thicker, less wide and withdrawal with respect to the elastically deformable central finger (2₃). 10) Clamping assembly according to claims 1 and 7, characterized in that the crampons-stops (2) have in section, the general shape of a Z, the fingers being raised relative to the flange 2₁ for fixing the crampons. 11) Clamping assembly according to claim 1, characterized in that the eccentric studs (16) are associated with a smooth sheath (24) or with a sheath with a raised shoulder (26, 27). 12) Clamping assembly according to claim 1, characterized in that the slider comprises a crampon (21), angularly adjustable replacing the crampon-stop (2) to adapt to workpieces having non-parallel edges. 13) Clamping assembly according to claim 1, characterized in that the fixing means of the plate (1) consist of lower studs (4) housed in recesses (38) formed under the bearing face (1₁) of the plate (1), these studs comprising an annular shoulder 4₁) for receiving the head (39₁) of a fixing screw (39) engaged in a threaded orifice of the plate (1). 14) Clamping assembly according to claim 13, characterized in that the lower clamps (4) comprise two fingers (4₂) projecting slightly on the edge (8) of the plate (1), these being bent upwards towards the upper face of the plate to ensure self-plating when tightening the jaws of a vice. 15) Clamping assembly according to claim 1, characterized in that the fixing means of the plate (1) consist of flanges (28) sliding in lateral grooves (7) of the plate, the latter being associated with one part to flange supports (29) provided with a support seat (29₁) on the other hand to the table supporting the plate by studs (30) screwed either in tapped holes (33) of the table or in cleats (31) with T section housed in the corresponding grooves of said table. 16) Clamping assembly according to claim 1, characterized in that the flanges (28) are formed of a parallelepiped metal block pierced with a central orifice traversed by the fixing studs (30) whose head is provided with a blind hole (32) with hexagon socket, the threading of said studs having a differential pitch to ensure energetic clamping. 17) Clamping assembly according to claim 1, characterized in that each slide consists of a base (12) with inverted T section of shape corresponding to the grooves (5) and sliding therein, this base being associated with a cleat (13) also of T section, independent of the base but joined to the latter by a locking screw (15) and by a centering pin (41), the cleat (13) having one end projecting from to the base (12) (in its longitudinal direction), a trident crampon (16) (coupled to this same end) projecting from the cleat (13) and overhanging the base (12). 18) Clamping assembly according to claim 17, characterized in that the triden clamp (16) is coupled to the cleat (13) by an axis (17 or 22) with an eccentric head or not. 19) Clamping assembly according to claims 7 and 9, characterized in that the contact faces of the rigid stops constituted by the middle finger (16₂) of a triden stud (16) with eccentric in opposition with the two outer fingers (2₂ ) a crampon-stop (2) define a triangular support on the workpiece held between them.

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