CH632950A5 - Device for clamping a turbine machine blade and transfer machine comprising such a device - Google Patents

Description

The present invention relates to a device for clamping during machining of a turbomachine blade whose blade is with finished dimensions, at least for its dimensions other than its height relative to its foot, as well as a transfer machine comprising such a device.

The machining of blades of turbine engine blades has so far not been carried out on a transfer machine. The object of this invention therefore consists in allowing such machining on a transfer machine.

Consequently, the first object of this invention, tending to achieve the above-mentioned object, consists of a device for clamping during the machining of a turbomachine blade, the blade of which is with finished dimensions, at least for its dimensions other than its height. with respect to its base, characterized in that it comprises a support to which the machining forces are not transmitted, support provided with means for orienting and gripping the blade by its blade in which the blade is held permanently, a first means of clamping in position acting in an antagonistic manner on the sole and the face situated at the base of the blade of the foot of the blade, whose line of action coincides with the direction of the result of the forces generated by a first machining operation intended to establish two parallel reference faces on the blade root, and a second clamping means in position acting antagonistically on the two reference faces thus determined in view of 'operations' subsequent machining.

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According to a preferred embodiment of the device, the support may include means for orienting the blade and means for gripping the latter by its blade. The blade is then held by its blade in this support during all the machining operations, possible transfers and control. The orientation means generally consist of six studs forming six reference points on which the blade must rest freely during its introduction into the support. Three of these non-aligned points relate to the upper surface of the blade, two to its leading edge, and the last is either on the free end of the blade, if it is not to be machined, or, otherwise, on the face of the foot located at the base of the blade. Verification of the effective contact of the blade on these six reference points can be carried out by electrical means and materialized by a visual device.

When the contact condition has been checked, the gripping means with which the support is fitted come into action. These ensure that the blade of the blade is clamped against the first five reference points cited, namely the three upper surface points and the two leading edge points. These gripping means must not cause deformation of the blade or movements thereof, sliding for example, relative to the reference points, so as not to change the orientation of the foot of the blade. The gripping means advantageously consist of two series of pushers, the first of which applies the upper surface of the blade against its reference points and the second of which applies the leading edge of the blade against its reference points. The distribution, number and tightening force of the lifters will be determined according to the flexibility characteristics of the blade.

According to different variants of the device, the production of the support will depend on the geometric characteristics of the blade, the arrangement of the first and second clamping means and the machining to be carried out.

In the case of a blade whose free end of the blade is not subjected to machining, the support may include a cavity closed at one of its ends into which the blade is introduced by its blade, its foot remaining cleared so that it can be machined.

In the case of a blade whose end of the blade also undergoes machining, the support must only grip a part of the blade between its free end and its base; the cavity receiving the blade will then be open at its two ends.

The studs constituting the reference points can be arranged in the cavity, as well as the gripping pushers. These pushers can, according to a first embodiment, be kept constantly in the irreversible active position by calibrated elastic means belonging to the support. By irreversibility is meant the impossibility of retracting the pushers by acting on their active part. The release of the pushers must be ensured in this case by a device provided on the frame of the machine carrying out the machining at the places where the loading and unloading of the blade takes place, in order to allow respectively the introduction of its blade in the support cavity before machining and its removal from said cavity after machining and control. In a second embodiment, the positioning of the pushers and their removal are carried out by means provided for this purpose on the machine performing the machining operations.

In both cases, the blade is maintained in the optimal position, after application of the gripping means belonging to the support, the proper orientation of its foot being guaranteed by the bearing on the six reference points. It should be noted that the forces necessary for gripping must not lead to deformations of the blade, but be sufficient to prevent any modification of the position of the blade in its support under the effect of relatively low stresses, vibrations of the machine or accidental impact for example, independently of any other tightening means. The gripping force is however not sufficient to oppose movements of the blade under the effect of machining forces.

The first design of pushers, that is to say constantly maintained in an irreversible active position, makes it possible to envisage the transfer of the support with preservation of the relative position of the blade from one machine to another, or between different stations machining, the correct positioning of the blade relative to the machining means then being ensured by reference points of the support itself.

The first clamping means exerting their antagonistic action on the face of the foot located at the base of the blade and on the sole of the dawn foot, they will advantageously consist of a device bearing on the face of the foot located at the base of the blade and forming a stop against the machining forces, and of a device bearing on the sole and applying the blade on said stop with a relatively moderate force. In addition, the device on the sole will be designed so as to prevent any rotational movement of the blade root around the line of action of the first clamping means.

Advantageously, the device bearing on the face of the foot situated at the base of the blade will consist of pushers integrated into the support, placed in position and locked, so as to form a stop by devices, jacks for example, belonging to the machine. The device on the sole will include keys the end of which forms an edge penetrating superficially into the sole of the foot so as to prevent any rotation of said foot around the line of action of the first clamping means.

Advantageously, the second clamping means consists of two jaws each secured to the end of a jack rod. These jacks are controlled synchronously, under low load, in a first phase called approach, one of them approaching the part first. It should be noted that the jaw stroke can be determined precisely, given the existence of the reference faces; docking under these conditions can be made as a hard stop. The other bit then docks. One of the cylinder rods is then immobilized in translation. The jaws are finally tightened by simultaneously increasing the load on the jacks. The effort is thus maintained on the two rods during all subsequent machining operations. This way of proceeding makes it possible to produce a fixed stop, by immobilizing one of the jaws, against which the foot of the blade remains constantly applied by the free jaw.

The clamping device can be used for machining on the same machine different types of blades, a support being designed for each type of blade, the adjustment of the clamping and machining means on the machine being carried out according to the type dawn and desired machining.

A second object of the invention consists of a transfer machine for the machining of a turbomachine blade, in particular of its foot, comprising a frame and a plate, movable in rotation about a fixed axis, divided into a certain number of sectors which pass successively in front of the same number of fixed stations where loading, machining, control and unloading of the blade are carried out, and each sector comprising a device for clamping a turbomachine blade as described above, the blade of the blade being with finite dimensions, at least for its dimensions other than its height relative to its base, and which is characterized in that each sector of the plate is provided with a clamping device of which the support contains means for orienting and gripping the blade, as well as a device for controlling, locking in place and unlocking the gripping means contained in the support, the first tightening means comprising associated pushers at the top port and controlled by a device associated with the frame of the machine, and a movable element pressing on the sole of the blade and provided on the frame of the machine at the first machining station where the reference faces are machined on the foot, the second clamping means comprising, for each sector of the plate to which it is secured, two jaws controlled by jacks.

A particular embodiment of the invention will now be described, by way of nonlimiting example, with reference to the appended drawings in which:

fig. 1 schematically represents a transfer machine on the plate of which blades during machining are held in a clamping device according to the invention, the axis of rotation of the plate of the machine being perpendicular to the plane of the figure;

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fig. 2 schematically represents the first machining station seen from the center of the plate;

fig. 3 schematically represents the second machining station seen from the center of the plate;

fig. 4 schematically represents the third machining station seen from the center of the plate;

fig. 5 schematically represents the fourth machining station seen from the center of the plate;

fig. 6a and 6b show in two parts the mounting of the support containing the orientation and gripping means on the machine platform, the axis of the platform being in the plane of the figures parallel to the line X'X and to the left of that -this;

fig. 7 shows the support seen according to arrow F7 in FIG. 6a; fig. 8 is a sectional view of the support along the line Fs in FIG. 14, certain elements belonging to the cutting plane represented by the line F'a of FIG. 12;

fig. 9 is a sectional view of the support along line F9 of FIG. 11, some of the elements belonging to the section plane represented by the line F'a of FIG. 12;

fig. 9a is a sectional view along line F9a of a detail in FIG. 9;

fig. 10 is a sectional view of the support along the line F10 of FIG. 14, certain elements belonging to the cutting plane represented by the line Fs of FIG. 14;

fig. 11 is a sectional view, the elements of which belong either to the section plane Fn in FIG. 10, or in plane F'u of FIG. 9; fig. 12 is a sectional view along line F! 2 of fig. 8;

fig. 13 is a sectional view along line F13 of FIG. 10;

fig. 14 is a sectional view along line F14 of FIG. 8;

fig. 15 is a schematic sectional view of the second clamping means.

The transfer machine shown in fig. 1 comprises a movable plate 1 divided into a number of equal sectors: la, lb, le, ld, le, or five in this case. The axis of rotation 2 of the plate 1 is perpendicular to the plane of the figure. The machine includes stations 3a, 3b, 3c, 3d, 3e, the number of which is equal to that of the sectors of the platform.

At station 3a, the blade is loaded into its support, the dimensions are checked after machining and the blade is unloaded. At station 3b, the machining of two opposite lateral faces of the blade root takes place, with a view to establishing reference surfaces on which the second clamping means will rest in position of the blade. At stations 3c, 3d, 3e, certain machining operations take place, either successively: circular machining of the sole of the foot, machining of the free end of the blade and symmetrical grooving of the face of the foot located at the base of the blade.

In the example chosen, the foot and the free end of the blade of the blade are machined, so the support comprising the orientation and gripping means must leave these parts free and enclose only a portion of the blade located between its free end and its base.

Each sector of the plate is equipped with such a support which is secured to it in a removable manner, each sector having means for correctly positioning the support. The supports adapted to receive a type of blade can thus be replaced by others for the machining on the same machine of another type of blade, the fixing points, as well as the means for positioning the supports on the plateau, which can however remain invariant.

The detailed description of an embodiment of such a support will be made with reference to FIGS. 6 to 14.

The support 5 comprises a body 6 and an articulated part 7 movable around an axis 8 fixed relative to the body 6. The articulated part 7 is shown in the open position in dotted lines and designated by the reference 7a in FIG. 7. The part 7 comprises a stop 9 which comes into contact with a stud 9a, located on the body 6, in the closed position. A hook 10, movable in rotation about an axis 10a, belonging to the body 6 and constantly returned to the active position by a spring 10b, engages in a housing 10c of the part 7 to ensure its locking in position (fig. 9 ). Part 7 being in the closed position, the support 5 has a cavity 11, open at its two ends, in which the blade of a blade 12 can be clamped, the foot 12a and the free end 12b of which are released so as to be able to to be machined. This support 5 is mounted on the plate 1 of the transfer machine on which it is positioned and to which it is fixed in a removable manner, for example by screws and pins. The cavity 11 contains the means for orienting and gripping the blade.

The orientation means consist of six reference points on which the blade must rest freely after its introduction into the cavity of the support. Note that the introduction of the blade in the cavity is done with the movable part 7 in the open position (7a). This makes it possible to reduce the transverse dimension of the cavity in the case where the profile of the blade widens from its base towards its top.

The reference points consist of studs, three of which 14,15,16 relate to the upper surface of the blade, two others 17,18 on its leading edge, and the last 19 on the face of its foot located at the base. of the blade. For the location of these points, refer to figs. 8, 10 and 14. The verification of the effective contact of the blade on the six points is done by an electrical device comprising pilot lights. An embodiment of such an electrical circuit for checking the contact will be described with reference to stud 14 (fig. 10). This circuit is formed by a rod 141 whose end in the form of a spherical cap must bear on the upper surface of the blade. The shouldered rod 141 is fixed in a bore in the body 6 by means of an insulating sleeve 142. This rod is integrated in an electrical circuit of which a conductor 143 is shown, comprising in series a current source and a pilot lamp, which is closed by contact between pad and blade, which ensures the visualization of this contact. Each of the pads 14 to 19 can be included in such a circuit. The body 6 of the support comprises holes such as 20 for the passage of the conductors belonging to the different circuits. It is advantageous to also provide a device authorizing the start-up of the machine only in the case where the blade is actually in contact at its six reference points. After checking the contact, the part 7 is put in the closed position and locked by the hook 10. In order to maintain the blade without deformation in the cavity, the part 7 is provided with a pusher 21 resting on the lower surface of dawn (fig. 9). The pusher 21 slides in a bore 21a of a part 22 attached to the movable part 7. Between the part 7 and the part 22 is formed a chamber 22a containing a thrust plate 23 whose function will be described below. The pusher 21 is provided with a spring 21b resting on the plate 23 and which constantly pushes it towards the lower surface of the blade. The spring 21b has characteristics such that the force exerted by the pusher 21 is minimal.

The contact of the blade on the reference points being checked, the support 5 is put in the closed position, that is to say that the movable part 7 is locked (fig. 8 for example). The gripping means can then come into action.

In the example chosen, these gripping means are formed by a pusher 24 acting on the trailing edge of the blade and applying the leading edge of the latter against its two reference points 17,18 and three plungers 25,26,27 acting on the lower surface of the blade and applying the upper surface of the latter against its three reference points 14,15,16 (fig. 8 to 10). The pusher 24 is disposed approximately on the perpendicular bisector of the segment joining the reference points 17,18. The pushers 25, 26, 27 are arranged substantially opposite the reference points 14, 15, 16, the relative position between these push buttons and the reference points being determined so that the straight line joining the points of contact with the blade, of the reference pad and the pusher facing it, ie substantially normal to the average fiber of the blade profile. The aim of this precaution is to avoid any movement of the blade when it is gripped by the pushers 25, 26, 27 and is essential in the case of blades whose blade is very flexible. It will be noted that, for a rigid blade, it would be possible to reduce the number of pushers acting on the lower surface of the blade, for example by having only two, acting on the line which joins the reference point 27 in the middle of the segment

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determined by points 25 and 26. The pusher 21 is not part of the gripping means. It is used only for the temporary maintenance of the blade while waiting for the actuation of these.

The description of the means for operating the pushers 24, 25, 26, 27 will be given in detail with reference to FIGS. 8 to 10.

The pusher 24 (fig. 9) is formed by a rod 24a sliding in a bore 24b of the body 6. One of its ends 24c comes into contact with the trailing edge of the blade, the other end 24d being secured to a spring 24e. This spring 24e exerts a compression force of low intensity (of the order of that of spring 21b), tending to keep the pusher 24 constantly in the active position, so as to apply the blade against the reference points 17 and 18 during of its implementation. The rod 24 has a notch 24f having a flat surface 24g forming an inclined plane. The tightening of the rod 24 is effected by means of a rod 28. This rod 28 slides in a bore 28a of the body 6 of the support 5, and is returned upwards by a spring 28b. One of its ends has a notch 28c forming an irreversible inclined plane which cooperates with the surface 24g. The downward movement of the rod 28 thus causes the rod 24 to be clamped in position. The rod 28 has at its other end a head 28d on which acts a control means which will be described below. It will be noted that the end 28d has been designed independently with respect to the rod 28 to allow the opening of the part 7.

The pushers 25, 26, 27 (FIGS. 8 and 10) are formed by rods sliding in bores 25a, 26a, 27a respectively of the part 22 attached to the movable part 7. They are controlled by means of the plate thrust 23. This is constantly returned to the rest position by springs such as 23a and 23b resting on the part 22. It will be noted that no other means of securing is provided and that the plate 23 thus has a certain freedom of movement between the walls of the chamber 22a. The plate 23 is actuated by a pusher 30 sliding in a bore 30a of the movable part 7. The rod 30 is controlled by a rod 31 which acts on it by means of an irreversible inclined plane (reference will be made to the operation of the rod 24). This rod 31 is constantly pushed back into the released position by a spring 31a. Its positioning is done by another rod 32, balls 33 and 34 ensuring the transmission of movement, given the angle formed between the bores 32a and 31b of the rods 32 and 31 respectively. To ensure that the rod 31 is released from its active position, it is further provided to make its end 31c cooperate with the fixed axis of rotation 8. The latter comprises a notch 8c which pushes the end 31c during the opening of the part 7. The rod 32 has a free end 32b on which acts a control means.

The ends 32b and 28d are controlled simultaneously by a bar 35 (fig. 7) integral with the tray sector on which the support is mounted. This bar 35 performs a helical movement imposed by its axis 35a between its released position and its active position shown in FIG. 7. In the active position, it comes to bear by a stud 9'a on a stop 9 'of the movable part 7, the stop 9' being aligned with the stop 9. The bar 35 is provided with adjustable studs 36 and 37 which come to bear on the ends 32b and 28d of the push rods control rods.

The operation of the gripping means is as follows: after introduction of the blade into the support and verification of the effective contact thereof on the six reference points, the movable part 7 is placed in the closed position by the operator; the element 35 is set in motion and comes to rest on the stop 9 '; the pads 36 and 37 previously adjusted push the ends 32b and 28d, causing the translation of the corresponding rods and the establishment of the pushers 24,25,26,27. The dawn is then maintained with the desired orientation, but under low load. However, the gripping force is sufficient to prevent any movement of the blade under the effect of low stress, for example the vibrations of the transfer machine. The relative freedom of movement of the part 23 allows a distribution of the forces and the races between the pushers 25, 26, 27.

The pushers 24 to 27 are removed by disengaging the bar 35. If the spring 31a is insufficient to push the rod 31 back, the latter can be disengaged anyway when the part 7 is opened when its end 31c will cover notch 8c. Similarly, the rod 28, which is in principle recalled by the spring 28b, will be released anyway during the opening of the part 7 by a device engaging in a notch 28e from its end. These measures,

a detailed view of which is illustrated in FIG. 9a, is constituted by a pin 28f pushed back by a spring 28g.

The blade being thus oriented and maintained in the means for gripping the support, it must then be immobilized to subject it to the first machining necessary for the establishment of the reference faces. This immobilization is carried out by the first clamping means, the description of which is given below with reference to FIGS. 6 to 14.

This first clamping means is formed by two pushers 38, 39 belonging to the support 5 and acting on the face 40 of the foot 12a of the blade located at the base of the blade, and of a movable part 41, belonging to the station where the first machining takes place and coming to bear against the sole 42 of the foot 12a.

The plunger 39 (fig. 11) consists of a rod 39a movable in translation in a bore 39b of the body 6, its positioning being effected by a rod 43. This rod 43 acts by one of its ends 43a on a inclined plane 39c consisting of a slot in the rod 39a. The displacement of the rod 43 upwards causes the displacement of the rod 39a to the right; the latter is removed by reverse operation of the rod 43. The other end 43b of the rod 43 protrudes from the sole 61a of the support 5. A rod 44 (fig. 6b) is secured to the plate 1 so to be free in translation relative to the latter. Its end 44a comes into contact with the end 43b of the rod 43. The other end 44b of the rod 44 is terminated by a cylindrical key, the role of which will be explained below. All of the rods 43 and 44 are constantly returned to the inactive position by a spring 43c. After the pusher 39 has been put in place by actuation of the rod 43, it is locked by a second rod 45 (fig. 10) coming to clamp the rod 39a on an inclined plane 39d thereof. The rod 45 is itself controlled by a rod 46 acting by its end 46a on a notch having an inclined plane 45a of the rod 45. The other end 46b of the rod 46 emerges from the sole 61a of the support 6. It is extended through the plate 1 by a rod 47 movable in translation (fig. 6b). The rod 47 is terminated by a cylindrical key 47a. A spring 46c constantly recalls all of the rods 46, 47 in the released position.

The implementation of the pusher 39, at the first machining station, is done as follows: the rod 44 is actuated upwards by a calibrated means provided on the machine. The pusher 39 then comes to bear on the face 40 of the foot of the dawn. The pusher 39 is then locked in position by actuation of the rod 47 upwards, which causes the displacement of the rod 45 bearing on the inclined plane 39d of the pusher. The withdrawal of the pusher 39 is done by disengaging the locking means first, that is to say that the rod 47 is withdrawn downwards. The rod 43 is then actuated, the cooperation of its end 43a with the inclined plane 39c causing the withdrawal of the pusher 39.

The rods 43 and 46 are controlled by the rods 44 and 47. To this end, a jack is provided on the machine at station 3b where the first machining takes place, this jack acting on the buttons on the ends 44b and 47a. This cylinder is terminated by a part 49 (fig. 6b) having a cross section in C, the opening of which is turned upwards, forming two branches 49a and 49b intended to cooperate respectively with the keys 47a and 44b. The part 49 also comprises on its bottom two studs 49c and 49d, of cylindrical shape, also intended to cooperate with the keys 47a and 44b. During the rotation of the plate 1, the keys 44b and 47a engage between the branches of the part 49 which is suitably arranged. The tightening operation is carried out by moving the part 49 upwards (arrow f49) under the action of the jack which controls it. The pad 49d comes to bear on the end 44b, which allows the introduction of the pusher 39. This pad 49d is mounted on a

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elastic compressible device, so as to allow the movement to continue.

The upward movement of the jack continuing, it is then the pad 49c, of a design similar to that of the pad 49d, which acts on the button 47a, which allows the locking in position of the pusher 39. For unlocking and removing the pusher 39, the part 49 must be moved downwards and it must be taken into account that the unlocking must be carried out first. For this purpose, the key 47a has a greater axial length than the key 44b, so as to first meet the branch 49a of the C formed by the part 49. The continuation of the movement only then causes action on the key 44b of branch 49b.

The part 49 and the relative arrangement of the pads with respect to the keys have been described by way of nonlimiting example. Other embodiments could be envisaged while respecting the order of operations, namely: at the outlet of the pusher 39, positioning first, then locking; upon removal of the pusher 39, unlocking first, disengagement of the pusher then.

The pusher 38 and its control and locking means are designed similar to those of the pusher 39 and will be described briefly.

The pusher 38 is formed of a rod 38a, the positioning of which is controlled by a rod 50 acting by means of an inclined plane 38b and the end 50a of which emerges from the sole 61a of the support. The locking means consist of a rod 51 acting on an inclined plane 38c of the rod 38a and controlled by a rod 51a whose end 51b also emerges from the sole 61a. The ends 50a and 51b are continued by movable rods in translation, through the plate 1, which end with keys also intended to cooperate with the part 49 in a manner identical to that described for the keys 44b and 47a. The pushers 38 and 39 are therefore controlled simultaneously at the first machining station. Their removal is carried out at this same station after the machining of the reference faces has been carried out.

The pushers 38 and 39 being in the active and locked position, the movable part 41 belonging to the first machining station then comes to bear on the sole 42 of the blade root (fig. 6a) so as to apply the face 40 of this foot against the stops formed by the pushers 38 and 39. The contact between the movable element 41 and the sole 42 is made by means of keys 52, 53, 54. The keys 52 and 54 have an identical design and will be described more precisely with reference to the key 52.

The key 52 slides in a housing 52a of the part 41 and has a notch which cooperates with a device 52b delimiting the possibilities of translation. The key 52 comes to bear on the bottom of its housing by means of an elastic buffer 52c. The other end 52d bearing on the sole comprises a hollow machining in the form of a spherical cap. This allows, under the action of a relatively small tightening, the surface penetration of the end 52d in the sole 42, thus preventing any movement of rotation of the foot in a plane transverse to the line of action of the tightening means.

The pushers 38, 39 and the movable part 41 being in place, the blade can undergo the first machining at station 3b. We will refer to fig. 1 and 2. The first clamping means is represented by the arrows b. Two milling cutters 301,302 mounted on the same head simultaneously machine the two lateral faces of the foot 4 which will serve as a reference. It will be noted that the relative arrangement of the cutters, their advance and their direction of rotation are such that the machining forces have a resultant the direction of which is the same as that of the resultant of the clamping forces in position. Fig. 2, which is a view of the station 3b from the center of the tray, shows the movement of the cutters 301 and 302.

This first machining completed, a second clamping means acting on the reference faces thus determined then comes into action. The plate 1 performs a first rotation bringing the blade thus machined to the station 3c. Previously, the first tightening means will have been

released, that is to say the part 41 removed from its active position and the pushers 38 and 39 retracted, as described above.

The second clamping means consists for each sector, in the present case, of two jaws, the description of which will be made with reference to FIG. 15 and which appear, in phantom, in FIG. 7 in active position.

Fig. 15 schematically shows, on a reduced scale, the second clamping means seen in a radial direction from the outside of the plate, in the released position. The Y'Y axis represents the vertical (parallel to the axis of the plate).

The second clamping means is formed by two jaws 55.55 ', each mounted at the end of a rod 56.56' of an actuator 57.57 'respectively. These jaws are schematically represented by the arrows c and d in FIG. 1. They come to bear on the lateral faces 401 and 402 of the foot of the blade machined at the first machining station. To avoid deformation of the blade root during docking by the jaw 55 ', a frank stop is provided on the support 5 (see fig. 15). This frank stop is constituted by a key 55'a belonging to the jaw 55 'and by a key 55'b belonging to the support 5.

The rod 56, 56 'of each of the cylinders 57, 57' comprises a hollow portion 58.58 'which is supplied with oil under pressure by a conduit 59, 59' and which controls the first phase of the movement of the jaws, consisting of a approach of the part under low forces thanks to the reduction of the surface on which the fluid under pressure acts. Arrangements are made for one of the jaws, 55 ′ for example, to land first on the part. For this it is possible, at equal speeds of the two rods 57 and 57 ', to reduce the stroke of the jaw 55' relative to the face 402, or, at equal strokes, to reduce the speed of one of the jaws (55 in this case), as will be explained later.

After the jaw 55 'has landed on the straight stop and the face 402 of the blade tip, the jaw 55 in turn comes into contact with the face 401 of the blade tip. The rod 56 'is immobilized in translation. The actual tightening is then carried out as explained below.

The rod 56.56 'of each of the cylinders 57.57' comprises, in addition to the hollow part 58.58 'which determines a chamber supplied with oil for docking, a piston 60.60' dividing a bore 61.61 'in two chambers 62, 63 (62', 63 ') so as to produce a double-acting cylinder. The piston 60.60 'has a large surface area and the tightening is carried out by admitting the pressurized oil into the chamber 62.62' through a pipe 64.64 'after the tightening of the two jaws is ensured. One of the jack rods, here 56 ′, is immobilized in translation by a deformable ring 65, the contraction of which is ensured by admission of pressurized oil around its periphery by a pipe 66. This deformable ring 65 comprises a metal part 651, determining a thin sleeve, surrounded by an elastomer sleeve 652. The assembly inserted into the body of the jack is therefore susceptible to radial contraction during the introduction of the oil under pressure.

The loosening of the part is done as follows: after release of the ring 65, pressurized oil is sent to the chamber 63,63 'via a line 67,67', the chamber 62 , 62 ′ being connected to the oil tank by a line 621,621 ′, likewise for the chamber 58,58 ′. The rods of the cylinders 57, 57 ′ can therefore move back and the blade can be released from the jaws. It will be noted that the evacuation pipe 68 from the chamber 63 includes an adjustable diaphragm 69 which makes it possible to throttle the emptying rate thereof during the approach and docking phase, and therefore to slow down the speed d 'advance of the jaw 55 during the approach phase, the pipe 68' for emptying the chamber 63 is not throttled.

During machining, the immobilization in translation of the cylinder rod 57 'by the device 65 guarantees the stability in position of the blade root. Continuous tightening against the fixed obstacle thus created is ensured by the jack 57.

The foot of the blade being immobilized in position, a series of machining operations can then be undertaken. These operations are

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described by way of example in the case of the machine shown in fig. 1.

At station 3c, circular machining of the sole 42 of the blade root takes place. The milling cutter 311 performing this machining, as well as its movement, are shown seen from the center 2 of the plate in FIG. 3. It 5 describes a rectangular cycle between the CO rest position, the working position C1 with machining up to C2, return to C3 then to CO.

After this second machining, the blade is transferred to station 3d where a circular machining of the free end of the blade takes place by a cutter 321. FIG. 4 is a view of the station 3d from the center of the plate 1, and io schematically shows the rectangular movement cycle of the tool 321: rest position DO, positioning in position Dl, machining up to D2, return to DO in passing by D3.

Dawn undergoes a final machining at the 3rd station. This machining consists of a symmetrical grooving of the face 40 of the foot located at the base of the pale ts. Fig. 5, which is a view of this station from the center of the plate 1, shows the two cutters 331 and 332 which successively carry out the machining of the grooves.

They each describe a rectangular cycle illustrated by the

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positions E0 (E'O), El (E'l), E2 (E'2), E3 (E'3), E0 (E'O) being the rest position.

The blade is finally transferred to station 3a where the control takes place, after the second clamping means is released. Unloading is then carried out by disengaging the bar 35 and opening the part 7 of the support. A new blade loading can then take place.

It will be noted that the simultaneous machining of four blades can be carried out on the machine described, a fifth being in the course of loading or unloading control. The immobilization time of the platform between two consecutive trips is equal to the time spent at the station where the operations are the longest. In the case of the machine described, it is the station where the control is carried out, the unloading of a machined blade, then the loading of a blade to be machined.

The support 5 is adapted to the type of blade to be machined, that is to say in fact to the dimensions of the blade; only the arrangement of the means of fixing the sole to the plate will remain invariant, sets of at least five supports being provided per family of blades.

R

11 sheets of drawings

Claims (12)

632950 1. Device for transfer machine for clamping during machining of a turbomachine blade whose blade is with finite dimensions, at least for its dimensions other than its height relative to its foot, characterized in that it comprises a support to which the machining forces are not transmitted, support provided with means for orienting and gripping the blade by its blade in which the blade is kept permanently, a first clamping means in the acting position of antagonistically on the sole and the face located at the base of the blade of the foot of the blade, whose line of action coincides with the direction of the result of the forces generated by a first machining operation intended to d 'Establish two parallel reference faces on the foot of the blade, and a second clamping means in position acting antagonistically on the two reference faces thus determined for subsequent machining operations. 2. Device according to claim 1 for the clamping of blades, during the machining of their foot, characterized in that the orientation means with which the support is provided consist of six studs, forming six reference points on which the blade must rest freely after its introduction into the support, three of these non-aligned points bearing on the upper surface of the blade, two others on its leading edge, the last on its free end, and include verification means effective contact of dawn on said pads. 2 3. Device according to claim 1 for the clamping of blades, during machining of their foot and the top of their blade, characterized in that the orientation means which is provided with the support consist of six studs forming six reference points on which the blade must rest freely after its introduction into the support, three of these non-aligned points bearing on the upper surface of the blade, two others on its leading edge, the last on the face of the foot located at the base of the blade, and comprise means for verifying the effective contact of the blade on said pads. 4. Device according to one of claims 2 or 3, characterized in that the gripping means which is provided with the support ensure irreversible tightening without deformation of the blade against the first five reference points, their implementation being controlled after verification of the effective contact of dawn on the six reference points. 5. Device according to one of claims 2 to 4, characterized in that the gripping means consist of two series of pushers, the first of which applies the upper surface of the blade of the blade against its three reference points and of which the second applies the leading edge of the blade against its two reference points. 6. Device according to claim 5, characterized in that a means is provided for ensuring the placing in the active position and the withdrawal of the pushers. 7. Device according to claim 5, characterized in that the pushers are kept constantly in the active position by tared elastic means associated with the support, their release being intended to be effected by a device provided on the machine performing the machining, at the places where loading and unloading of the blade, to allow respectively the introduction thereof into the support before machining and its removal from the support after machining. 8. Device according to one of the preceding claims, characterized in that the first clamping means in position comprises pushers associated with the support whose implementation, locking in position and unlocking are ensured by means provided on a station machining where the first machining operation takes place, which are based on the face of the blade root located at the base of the blade, and a movable part intended to be associated with the machining machine and which comes to rest on the sole of the foot of the blade to apply the face of the foot located at the base of the blade against the pushers associated with the support. 9. Device according to claim 8, characterized in that the movable part is designed so as to prevent any rotational movement of the foot of the blade around the line of action of the first clamping means. 10. Transfer machine for machining a turbomachine blade, in particular its base, comprising a frame and plate, movable in rotation about a fixed axis, divided into a number of sectors which pass successively in front of the same number of fixed stations where loading, machining, control and unloading of the blade are carried out, each sector comprising a device for clamping a turbomachine blade according to claim 1, the blade of the blade being at finished dimensions, at least for its dimensions other than its height relative to its base, characterized in that each sector of the plate is provided with a clamping device the support of which contains means for orienting and gripping the blade , as well as a device for controlling, locking in place and unlocking the gripping means contained in the support, the first clamping means comprising pushers associated with the support and controlled by a device associated with the frame of the ma china, and a mobile element pressing on the sole of the blade and provided on the frame of the machine at the first machining station where the reference faces are machined on the foot, the second clamping means comprising, for each sector of the plate to which it is secured, two jaws controlled by jacks. 11. Transfer machine according to claim 10, characterized in that the second clamping means of the device, acting after release of the first clamping means, comprises two jaws associated with the machine performing the machining operations, each controlled by a jack and which come lean on the two reference faces formed during the first machining operation, the jacks being controlled in synchronism under low load in a first approach phase, so that one of the jaws approaches the foot first, the clamping necessary for immobilization of the foot then being effected by increasing the load on the cylinder rods, a means of immobilization in translation acting before clamping on the rod of one of the cylinders. 12. Transfer machine according to claim 11, characterized in that each cylinder has a first reduced surface area on which the pressurized fluid acts during the approach phase, and a second surface area larger than the previous one , the pressure of the fluid being applied on one of the faces to ensure the tightening and on the other to allow the withdrawal of the jack.