MXPA97010079A - Device for placing a machine mandrel for its pil bar - Google Patents

Abstract

The present invention relates to a device for aligning a longitudinal axis of a rotary arrow of a machine tool with the axis of a cylindrical opening, characterized in that the pilot rod is coupled with the arrow is joined to align the arrow, the device comprises: a pre-adjustment bracket movably mounted in a bed of the machine tool, so that the pre-adjustment bracket in a horizontal plane; a ball holder mounted on the preset bracket; a bracket for holding the holder of the bracket; sphere with the pre-adjustment bracket, a first support to give a mobile support to the sphere holder in the pre-adjustment bracket when the bracket is released, so that the sphere holder can move in the horizontal plane; spherical mounted on the sphere holder, a support for the core to hold the fixed spherical core relative to the sphere holder, a second support for mobile support to the spherical core rich in the sphere holder when the core holder is released, so that the spherical core can rotate with respect to the sphere holder, a cover to hold the rotating shaft of the machine tool and an actuator to rotationally drive the rotating arrow, where the cover can move in a sliding way through a hole in the spherical core to place the rotating arrow in the working positions and retracted in relation to the workpiece, and balance the masses mounted on the spherical core, where the equilibrium masses cause a combined center of gravity of at least the spherical core, the equilibrium masses, the cover, the actuator and the rotating shaft are located along a central longitudinal axis of the arrow rotating and adjacent to the center of rotation of the spherical core when the arrow is in the locked position

Description

DEVICE FOR PLACING A MACHINE MANDREL FOR ITS PILOT BAR DESCRIPTION OF THE INVENTION: The invention relates to a device for aligning the longitudinal axis of a machining tool with respect to the axis of a valve guide in view of the precision machining of the seat or of any other port concentric to that bore. It relates more particularly to devices comprising, on the one hand, a pilot positioning bar, carried with the machining tool by a mandrel attached to means suitable for rotating it on an axially displaceable cover, on the other hand, a support adjustment, movable in the horizontal plane with respect to the sliders of a frame and following at least one longitudinal direction, or following two perpendicular directions, and further between the cover and the pre-adjustment support, an angular orientation means of the mandrel with relation to the vertical, this means being composed of a spherical nut traversed by the cover, resting on the lower spherical seat of a sphere holder, and cooperating with a tightening means in the machining position. With this type of device the alignment operation comprises: a pre-regulation phase consisting of placing the REF: 26499 devices above the seat by displacement of the pre-regulation support on the frame; a phase of releasing the means for blocking or retaining the elements of the device; a phase of descent of the cover in relation to the nut by motorized or manual control means with manual guidance of the pilot bar to facilitate the introduction of the pilot in the valve guide; an alignment phase that is carried out automatically using the rigidity of the bar between the pilot and the tool to bring the axis of the mandrel to coincide with the axis of the guide, by the relative displacement of the alignment device; finally, a blocking phase in position. According to the embodiments, the spherical nut is associated with pneumatic support means, as in WO-A-80/01365, to electromagnetic support means as in EP-A-2637766, or more simply it rests on a layer of material of a strong sliding coefficient covering the spherical seat that supports it, and this in order that after the release of the tightening means, can pivot freely in its seat to allow the orientation of the cover and consequently, that of the longitudinal axis of the mandrel. In the case of devices mounted on machines for rectifying valve seats that require an important motor coupling, an electric motor, fixed on the pre-adjustment support, is attached to the mandrel, for a transmission of movement, which even if it comprises a Intermediary telescopic shaft with two end gimbals to follow the angular movements of orientation of the mandrel, as in the FR-A 2501094, hinders the movements and needs in its automatic alignment, an important effort, unfavorable to the positioning precision sought. To this it must be added that when the pilot is introduced into the valve guide bore, and the pilot bar by its rigidity, it regulates the position of the mandrel when orienting it angularly, and moving it in the horizontal plane, this displacement is made in no matter which direction with respect to the mandrel, and imposes to move the set of organs and means carried by the device. For high-class machines, the mass to be moved is 140kg. Because of the inertia of this mass, and the friction between the guiding means that ensure cross-sliding, frictions amplified by the decomposition of the forces when the displacements of the Since the mandrel is not parallel to the crossed displacements, these displacements of the pilot bar are not carried out perfectly so that the reaction force developed by the pilot bar is opposite and the bar can not remain bent and the mandrel shaft can not be brought to coincide with that of the guide. This has the consequence of producing concentricity inaccuracies that can reach several hundredths of a millimeter, and then be unacceptable. These drawbacks are even more troublesome when a machine of this type is used for the rectification of valve seats of cylinder heads of multiple valves for example of four valves per cylinder that have guides of diameter less than or equal to 7mm, because the pilot bar having a diameter of the order of 4mm, it is more flexible and must retain a residual contraction with the risk of having a permanent deformation or when, as in EP-A 4 784 78, the device for placing the pilot bar is combined with means that allow Determine by palpation, the average geometric position of the longitudinal axis of housing for the valve. Indeed, in this case, and in spite of the freedom of movement donated to the spherical nut, the inertias and resistances various to the displacements in the horizontal plane, respectively, disrupt the alignment of the mandrel or the palpating movements of the internal face of the mandrel. the perforation of oval shape of reference. FR-A-250 1094 discloses an alignment device in which the ball-and-socket joint is carried by a regulating body which, in the alignment phase, can move backwards in a horizontal plane in relation to a fixed flange that contains it. of the alignment is blocked by reference bars. Such device suppresses the reactions that cause stress decompositions for the movements of crossed cars, but the rubs are added that adding to the obstacles exerted on the mandrel the cardan, they remove it from the traction means that generate alignment impressions that do not allow use this device for the machining of multivalve cylinder head valve seats. Furthermore, after the alignment, the actuation of the locking means of the regulating body can move this body parallel to itself, favoring, as shown in Figure 8, a support on the support that is eccentric with respect to the axis of the mandrel. and causes a flexure of the same, for tilting of this around its pilot fitted in the guide of the valve. Thus the imprecision of the automatic alignment receives the addition of an inaccuracy in the blocking place. These various drawbacks are increased in the alignment devices in which the sphere holder is based on alignment phase, by a flat air pad. In fact, it is found that during the phase of alignment, the various masses of the device and in particular those of the means of displacement in rotation of the mandrel, but also and mainly those of the translation in the mandrel, create tipping torques on the mandrel. mandrel-sphere assembly - sphere holder, which tend to donate to the flat pad a conical shape that favors, in the grip phase, the baculamiento of the sphere holder. This has the consequence, as shown in FIG. 8, of misaligning the axis of the mandrel with respect to the position defined by the alignment phase, and finally causing inaccuracies. The object of the present invention is to provide an alignment device which remedies these drawbacks by reducing the inertias and by eliminating most of the physical and mechanical constraints that follow the transmission of the mandrel's dragging movement and the guidance of transmission movements of this mandrel, in its sphere in relation to the sphere holder and in relation to the support. in order to achieve this effect, in the device according to the invention, the spherical clamp or holder carries masses that balance the mass of the translational traversing means of the cover and the mass of the cover and of the mandrel when they are in a position aligning down, the center of gravity of the assembly remaining basically on the axis of the cover, while the electrical means of motorization of the mandrel are arranged on the cover and so that when it is covered it is in a lowered position of alignment, the center of gravity of that cover is on the axis and near the center of the spherical clamp, that the means of generation of the flat pad between the support and the sphere holder comprised of sliders arranged in the support opposite the sphere holder and suitable for donating a film of uniform thickness, and that the gripping means comprise discharge means other than the lift glides and suitable for being joined to a vacuum source. Thanks to this arrangement, when the clamping means of the clamp release it to allow aligning the mandrel with the valve guide, the angular orientation of the mandrel is not impeded by a mechanical transmission that creates an oriented effort. Furthermore, the suppression of this mechanical transmission considerably reduces the value of the mass before it is displaced and reduces the inertia. In addition, the organization of masses on the roof, the balance of the masses the set, the placement of the center of gravity on the axis of the cover plus the center of the clamp and the support of the sphere holder by a uniform air film, they eliminate all external obstacles, so that the sphere holder has a total freedom of movement in the horizontal plane and does not generate any obstacle in the automatic alignment of the mandrel, due to the reaction of the pilot fitting in the guide. likewise, this arrangement favors the displacements of the device and eliminates all the parasitic obstacles in the operation of tapping a perforation by the pilot. Finally, the balance of the sphere cover-sphere-sphere assembly, combined with the production of a flat film of uniform thickness, guarantees the parallelism between the lower face of the sphere and the upper one of the support and avoids, when the depression grip, any inclination of the sphere holder in which any modification of the precise alignment is made in the preceding phase. It thus appears that the placement of the center of gravity of the head, the distribution of the feeding means of the mandrel motor, the formation of the flat and constant thickness supporting film, and the vacuum grip cooperate to a common objective which is obtain a perfect alignment of the mandrel with the valve guide. In an embodiment of the invention, the unlocking trajectory of the piston ensures the locking of the spherical clamp by cooperation with the lower spherical seat of the sphere holder, is limited by three adjustable stops separated by 120 ° in a fixed wall of the holder -sphere. If in the phase of alignment, the air cushion that is formed between the lower spherical seat and the spherical handle is calibrated by the cushion that is formed between the handle and the upper seat, because that seat itself is perfectly placed to support from back to the locking piston on the three stops. It follows that any transverse displacement of the spherical clamp is prevented and that the alignment operation gains in precision. In one embodiment of the invention, the supply of the electric motor arranged in the cover is ensured by an external circuit which comprises a removable skate cooperating with contact members carried by the clamp, on one side and on the other of its diametrical plane, and being part of an internal circuit of the clamp. Thus in the phase of alignment the skate is felt or detected, and is brought to a position of disappearance to leave all freedom of movement to the spherical clamp. This has the consequence of freeing that clamp from all obstacles, to minima that result from the power supply of the electric motor of the mandrel. After positioning, the skate is brought to an operating position, that is, it moves radially in the direction of the clamp to ensure the feeding of the electric motor. Advantageously each of the sliders carried in the support to form the air film that supports the sphere holder, presents on its compressed air supply circuit a regulating organ for its expense.

This distribution allows, in a simple way, the regulation of the expenses of different sprinklers to obtain a film of constant thickness, which guarantees, between the phase of alignment and the blocking phase, and thanks to the placement of the center of gravity of the head in the soul of that, a parallel descent of the sphere holder in relation to the support. Other features and advantages will be apparent from the description that follows with reference to the attached schematic drawings which represent, by way of example, various embodiments of the device according to the invention. Figure 1 is a partial perspective view schematically showing a tool holder according to the invention in the placement phase; Figure 2 is a cross-sectional side view showing an embodiment of the device, when equipped with a scroll wheel of the cover; Figure 3 is a front elevation view of the device shown in Figure 2; Figure 4 is a sectional side view of another embodiment of the device; Figure 5 is a longitudinal sectional view of an embodiment of the cover containing the motorized mandrel; Figure 6 is a partial sectional view, showing in enlarged scale a variant embodiment of power supply for the mandrel motor; Figure 7 is a sectional side view showing a variant of the fastening means; Figure 8 is a schematic side view that illustrates in a greatly enlarged way the alignment defect resulting from a mechanical fastening acting on a support film of irregular thickness. In that drawing, the figure 1 indicates the bottom of a cylinder 9, Fig 1) and 2 in general, the frame of the machine equipped with longitudinal sliders 3 for a preregulation support 4, wherein the guidance is secured by roving elements 5. The mandrel 6 is provided with a tool holder 7 in which a tool 8 can be placed with its pilot bar 9. This mandrel is mounted free to rotate in a cover 10. The latter is rotated and mounted by sliding in the internal perforation 12 of a spherical clamp 13, with the possibility of displacement controlled by device, of the motorized or mechanical type. In Figure 2 this device is constituted by a gear 11 driven by a flywheel 11b and cooperating with a rack 11c placed on the cover 10. The translation guidance of the cover 10 is completed by a lower support 14, integral with the clamp spherical 13 and crossed by the lid tree joining the wheel 11b to the cog wheel lia. Reference 73 indicates an equilibrium gas spring that interposed between the spherical clamp 13, and a support 74, attached to the cover 10, has the purpose of accumulating energy when the cover descends to restore it when climbing, but also to hold the cover when the flywheel 11b is not actuated. The spherical clamp 13 is rotated about the axis of the cover 10, by means not shown and has a lower spherical carrier 15, which rests on a seat 16, in the form of a spherical cup and is integral with a sphere holder 17, carried by the support 4. An upper spherical port 18, of the clamp 13, is intended to cooperate with the corresponding concave port of a mounting means constituted here by a piston 19, movable vertically in the sphere holder 17. In the forms of represented embodiment the piston 19, moves in the direction of the grip of the spherical clamp 13, by a compressed air circuit that reaches the chamber 20, arranged between the upper face of that piston and a fixed ring-shaped wall 22, of sphere holder 17. The means represented here correspond to those described in the international application WO-A-80/1365, and will not be described in detail, in any case it should be specified that when the device is in alignment alignment position or palpated, the chamber 20 is connected to the atmosphere to release the piston 19, and the compressed air is introduced through a channel 21, into the central chamber 23, arranged between the clamp 13, and the body 17, on the one hand, to support vertically the clamp and on the other, forming two air cushions or pads between the spherical ports or supports 15 and 18, of that clamp and the seat 16, and the piston 19. The assembly that has been described, constitutes a means of angular orientation of the clamp 13, and of the clasp 6, which allows, as shown in Fig. 1, to align the axis x'x, of the mandrel, with the longitudinal axis of a valve guide 24, coaxial with the valve seat 25, from which the guide recessing in which the pilot 9 is fitted must be secured. As shown more in detail in Fig. 5, the cover or liner 10 contains guide supports 26 and 27 for the rotation of the mandrel 6, thus forming housing for an electric motor 28, and for means 2 9, which transmit the movement between its output shaft 30, and the end of the mandrel 6. In the embodiment shown, the means 29, are constituted by a reducer, but can take any other form without leaving the frame of the invention . Thanks to that, the center of gravity G, of the head formed by the cover and the elements that are contained therein, which are supported and carried, are arranged on the x'x axis of the mandrel 6.

In addition, and according to another characteristic of the invention, the spherical clamp 13 has masses 13a, 13b, which balance the msisas of the means lla-lld, of translation translational of the cover 10, but also the mass of this cover 10, and from mandrel 6, when the latter are in the alignment position this is knocked down. This balance is intended to maintain the center of gravity of this assembly on the x'x axis of the cover 10, and to suppress the pairs of parasitic forces on the movements of the mandrel in the alignment phase. Furthermore, these various elements are arranged with respect to each other, so that when the cover is in aligning position this is lowered to allow the introduction of the pilot 9, in the valve guide 24, the center of gravity G, this near the center C, of the spherical clamp 13, as shown in Fig. 1. In Figs. 2 to 5, the feeding of the electric motor 28 is ensured by an axial connector 32, which ends a flexible cord 33, wound in a helix and where the upper end is joined to a power 34, integral with the sphere holder 17. Thanks to this disposition the cord exerts a very weak effort on the machining head, being unable to disturb its various movements in the alignment phase. Fig. 2, shows well that, thanks to that particular assembly, the head of the machine is devoid of all transmission and that for this reason the angular orientation of the mandrel 6, is freed from all the inherent obstacles to that transmission. This is the same for the movements of displacement in the horizontal plane, movements that devoid of the inertia of the motor and of the intermediate transmission are carried out without important start-up effort, thus, very freely. The sphere holder 17 has a generally cylindrical shape and is integral with a cylindrical collar 35, whose lower face 35a rests directly on the upper face of the pre-adjustment support 4. It can be used alone or can be arranged in a box cylindrical 36, fixed on the support 4, and having an internal bore 37, of a diameter greater than the outer diameter of the collar 35, so that a radial play with this collar is established. Likewise, the upper wall 38 of the box is separated from the upper face of the collar 35, so as to allow free movement thereof. This upper wall has an axial opening 39, in which the diameter is larger than the outside of the cylindrical body 17, and the support 4 is crossed by an opening 40, larger in diameter than the outer diameter of the lower support 14, integral of the clamp 13. It is easily conceived that thanks to this structure, the sphere holder 17, and consequently the clamp 13, the cover 10, and the mandrel 6, can move radially in all directions from the longitudinal axis of the body, as shown by the arrows 31, in Fig. 1, but also with translation to a part and another of the theoretical longitudinal axis of the box 36, and this in the limits allowed by the radial clearance between the collar 35, and the perforation internal 37, of the box 36. This disposition eliminates all the inconveniences inherent to the use of cars of crossed movements or other movements that have a direction oriented by an obstacle and allows in the In case of a machine for the machining of valve seats, do not use the movements of the support 4, other than to pre-position the head with respect to the working area on the bottom of the cylinder 1 (Fig. 1). To facilitate this movement and as shown in Fig. 2, the support zone 4, which is underlying the box 36, and more especially the displacement zone of the collar 35, is crossed by channels 41, attached to a circuit 42, of gas under pressure 49, and especially of compressed air, controlled by a distributor 61. Under these conditions, the supply of channels 41, or the air under pressure produces an air film 71, between the collar 35, and the support 4, film that ensures the support of the sphere holder 17, and all the organs it contains, and facilitates the displacements of this body in relation to to the support 4. This distribution reduces rubbing and allows, in combination with the two air cushions, to favor the orientation of the spherical clamp 13, in the alignment phase, to release the head from all obstacles and during the probing and probing to release the assembly of palpation of all effort facilitating this operation. It is necessary that the indications made by the scanning operation be recorded by mechanical or electronic means that have not been described, as they have no relation to the object of the invention. Advantageously and as shown in FIG. 6, the fixed annular wall 22, of the sphere holder 17, is crossed by three screws 75, parallel to the axis x'x, distributed at 120 degrees, one from the other and which constitute stops for the piston 19. Thus, when the chamber 20 is connected to the atmosphere and the compressed air is introduced into the chamber 23, the recoil of the piston 19, puts its rear part in perfect support against the three stops 75, so that it fits perfectly placed. The same happens for its spherical seat 19a, which thus calibrates the air film passing between it, and the upper support 18, of the clamp 13, this calibration ensures the self-centering of the spherical clamp 13, and the calibration of the film of air passing between its port or lower support 15, and the seat 16, of the sphere holder. This arrangement avoids any decentering of the spherical clamp 13, which could influence the alignment operation and subsequently on the tightening or clamping precision.

When the alignment or palpation operation is completed and the position of the mandrel is definitive, it is blocked in that position, the spherical clamp is adjusted by pneumatic displacement of the piston 19, and then the sphere holder 17 is controlled. avoid as shown in Fig. 8, that in this control or tightening the collar 35, take support on the support 4, at 35d, that is leaving the center to cause eccentric tilting of the sphere holder 17, and tilt of the x-axis 'x, of the mandrel 6, around the engagement or fitting of the pilot 9, in the guide 24, and under an angle "a", and consequently this axis displaced with respect to its position defined by the alignment operation with the axis of guide, means have been provided to form an air film of constant thickness between the support 4, and the sphere holder 17, and other means that perform the suppression of that film. The means that give a constant thickness to the air film are constituted by sprinklers or nozzles 47, which disposed at the exit of the channels 41, are each associated to an organ 48, for regulating its expense, as shown in FIG. 6. Thanks to the placement of the center of gravity on the axis x'x, of the assembly comprising the sphere holder, the spherical clamp and the cover or the regulation of the sprinklers, it is possible to obtain a flat air film 71, of uniform thickness and to obtain in the adjustment the displacement of the sphere holder in parallel as well. The means organizing the suppression of the air film 71, and consequently the adjustment or tightening are constituted as shown in Figs. 2 and 6, by channels with outlets 62, other than channels 41, with sprinklers 47, are connected via conduit 63, to a distributor 64, being able to isolate them or put them in communication with a vacuum source 60. With this arrangement, as the alignment operation is determined the distributor 71, manual or electromagnetic command is operated to cut the compressed air supply 49, and put the air film 71, in communication with the atmosphere 79. Because of the regular thickness of the film and its thin thickness, of the order of a few hundredths of a millimeter, the sphere holder 17, descends parallel to itself always following the axis of the mandrel, thanks to the guide secured by the sliding of the pilot 9, in the valve guide 24. When the sphere holder 17 rests on the support 4, the distributor 64 is operated and places the channels 41, with the outlet 62, in communication with the vacuum source 60, in order to create a depression that blocks the The sphere holder 17, on the support 4, and ensure the tightening or control of the obtained position. That tightening, is usually sufficient to withstand the cutting efforts that are usually encountered, however, can be completed by a mechanical brake. In Figs. 2 and 4, the means of control or mechanical brake, are constituted by several jacks or elevators, tires 45, distributed around the sphere holder 17, and wherein the bodies are fixed on the upper face 38, of the case 36, while that its bar crosses that wall 38, to come into contact with the upper face of the aforementioned collar. In the variant shown in FIG. 7, the elevators 75, for example in the number of three and distributed 120 degrees around a longitudinal and vertical axis of the box 36, are arranged below the support 4, against which their bodies 66 are fixed. Their pistons 67, are equipped with a tubular means 68, which is crossed by an axial bar 69, each bar whose upper end is screwed in the collar 35c , of the body 17, passes through a perforation 70, of support 4, and the tubular means 68, with a set corresponding to the play of displacement of the collar 35c, in the box 36. Finally, its lower end protruding from the middle is integral with a lining 72, capable of receiving the thrust of the means 68, of the piston 67. Thus, when the collar 35c, is supported by an air cushion 71, the braking jacks 65, do not oppose their displacements, and when there is braking or control the effort of the elevators is transmitted directly by the bar 69, to the collar 35c.

In the embodiment shown in FIG. 4, the device differs from the preceding one by the fact that the center C, of the spherical clamp 13, is basically arranged in the horizontal plane H, of the upper face of the support 4. this way, the cylindrical body 17a extends to one part and another of the collar 35b, and in its lower part it passes through an opening 46, of the support 4. Thanks to this arrangement, the angular orientation of the mandrel is independent of its positioning of the plane horizontal, which improves the conditions of alignment or palpation. Finally, in order to suppress the very slight obstacle or discomfort that could be caused by the power cord of the electric motor 28, it is possible to replace that type of supply with that represented in FIG. 6, basically taking place in the horizontal midplane of the spherical 13, this feed is composed of an internal circuit comprising: - longitudinal bars 50, electrically conductive material that exceed the outer face of the cover 10, and electrically connected to the power circuit of the electric motor disposed inside the cover , - knots or contact points 52, leading to the axial perforation 12, of the clamp 13, and suitable for contacting the bars 50, - and parts of circular bars 53, which exit to the outside of the clamp distributed to one side and the other of its diametrical horizontal plane and electrically connected to the knots or points of contact by the circuits 54, - and an outer circuit leading to the contact shoe 55. This shoe carries spring contact points 56, electrically connected to the external supply circuit. The skate 55 is mounted floating on a means capable of moving it between an operating position in which its fingers 56 come into contact with the bars 53, and a separate position in which its fingers are away from those bars. In the represented embodiment, this means is constituted by an elevator 57, where the body is fixed on the outside of the sphere holder 17, and where the bar passes through to take support on a pin 72, on the skate. It is easily conceivable that in the adjustment phase the slide 55 is arranged in a separate position to completely release the clamp 13, and that after adjustment of the positioning of the tool, it is brought to an operating position with its fingers 56, in contact with the bars 53. It is necessary that, due to the low orientation angle of the clamp 13, in the regulation phase, in the order of 1 to 5 degrees, the positional variations of the contact faces of the bars 53, they are easily compensated for by the floating assembly of the skate 55, but also by the floating and elastic mounting of these contact fingers. It follows from the foregoing that the device according to the invention to release from all external obstacles, the means of regulation of the inclination and vertical position of the longitudinal axis of the mandrel, suppresses the blows, reduces stresses and makes the regulation more precise , with which, a concentricity of the order of 0.02mm can be obtained regularly. This device also favors the palpation that can be performed manually. It will also be noted that the suppression of the external transmission of a type of telescopic shaft and with double gimbals, between the motor and the mandrel allows to increase the speed of rotation of the mandrel, and obtain the necessary speeds for the machining of the seats and guides of valves of small dimensions. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers. Having described the invention as above, property is claimed as contained in the following:

Claims (9)

1. REINFORCEMENT 1.- Device for aligning the longitudinal axis of a tool with the axis of a valve guide, in which on the one hand the tool mounted on a mandrel is integral with a pilot bar coaxial with it and on the other hand the Alignment means comprise: a pre-adjustment support movable in the horizontal plane and at least longitudinally on a fixed frame, a sphere holder placed on the support with possibility in the placement phase of the mandrel and after the release of the means of control or braking displacement in all directions of the horizontal plane, thanks to a flat air cushion formed between the and the support, - a spherical clamp mounted on a seat of the regulating body with the possibility of free rotation in the phase of positioning or positioning the mandrel and after releasing the fixing means, - a substantially vertical cover or liner which e moves axially in the clamp and carries the tool driving mandrel, characterized in that the spherical clamp carries masses that balance the mass of the driving means for the translation of the cover and the mass of that cover and of the mandrel when they are in the lowered position of alignment, keeping the center of gravity of the assembly basically on the axis of the cover, while the electric means for the mandrel motor are arranged on the cover and so that when it is covered it is in a lowered position of alignment, the center of gravity is on the axis and near the center of the spherical clamp, and the generation means of the flat cushion between the support and the sphere holder comprise sprinklers or nozzles arranged in the support opposite the sphere holder and capable of provide a film of uniform thickness and the control or braking means comprise outputs different from the support sprinklers n and capable of binding to a vacuum source.
2. Device according to claim 1, characterized in that the unlocking course of the piston ensures the locking of the spherical clamp by cooperation with the lower spherical seat of the sphere holder which is limited by three adjustable stops distributed at 120 degrees to each other in a fixed wall of the sphere holder.
3. 3. Device according to claim 1, characterized in that the supply of the electric motor arranged in the cover is secured by a flexible electrical cord wound in a helix whose upper end is joined to a power linked to the body and in which the lower extremity is solidary of a connector arranged basically on the longitudinal axis of that cover.
4. 4. - Device according to claim 1, characterized in that the supply of the electric motor arranged on the cover is carried out by an external circuit having a removable skate that cooperates with contact members carried by the clamp to one part and another of its diametrical plan and that are part of an internal circuit in the clamp.
5. 5. Device according to claim 4, characterized in that the power supply of the electric motor is carried out on the one hand by electrically conductive longitudinal bars that come out on the outer face of the cover and come into contact with knots, leading to axial perforation. of the clamp these knots, are themselves electrically linked, by a circuit arranged inside the clamp having pieces of circular bars, which come out to the outside of the clamp and distributed to one part and another, of its diametral horizontal plane, and on the other hand by a skate that is carrying contact fingers with spring suitable to cooperate with the pieces of the circular bars, skate that is carried by the sphere holder and by a means capable of moving it between an operating position, in which your fingers are in contact with the bars and a withdrawal position, in which your fingers are separated from the bars.
6. Device according to claim 4 and 5, characterized in that the slide is mounted floating on the free end of the bar of a fluid jack or elevator where the body is fixed on the sphere holder containing the spherical clamp.
7. 7. Device according to claim 1, characterized in that each of the sprinklers or nozzles arranged in the support to form the air film supporting the sphere holder has on its compressed air supply circuit, a regulating organ of its expense to obtain an air film of a constant thickness.
8. Device according to claim 1, characterized in that the sphere holder is integral with a peripheral collar by which it comes into contact with the support and this collar is associated with means of control or mechanical training constituted by elevators arranged below the support against which their bodies are fixed, and by bars attached to the collar, each bar crosses with play a supporting hole and the tubular means of the corresponding elevator piston, and has at its lower free end a lining capable of receiving the push of the medium in the braking phase.
9. 9. Device according to claim 1, characterized in that the center of rotation C of the spherical clamp is in a horizontal plane defined by the face of the sphere holder resting on the support. SUMMARY OF THE INVENTION The alignment means of this device comprise a sphere holder (17), placed on a support (4), with the possibility in the placement phase of the mandrel (6), to move in all directions of the horizontal plane, a spherical clamp (13), mounted on the sphere holder (17), with the possibility of free rotation, a cover or liner (10), basically vertical axially displaceable in the clamp (13), and carrying the discharge mandrel of the tool. According to the invention, the spherical clamp (13), carries masses which balance the mass of the drive means for translation of the cover and the mass of that cover and of the mandrel when they are in the lowered alignment position, maintaining the center of gravity (G), of the assembly or set substantially on the axis (x'x), of the cover (10), while the electrical means (28, 29), for the motor of the mandrel (6), are arranged in the cover (10), and so that when this cover is in the downcast alignment position the center of gravity of this cover is on the axis (x'x), and near the center (C), of the spherical clamp (13) , and the generation means of the flat cushion between the support (4), and the sphere holder (17), comprise sprinklers (47), arranged in the support (4), and in front of the sphere holder (17), capable of providing a film of uniform thickness, and the control or braking means comprise outlets (62), other than the sprayer it is (47), of lift and capable of joining a source of vacuum.