SK170397A3 - Device for positioning a machining spindle using the pilot rod thereof - Google Patents

Abstract

Means for aligning the device include a ball holder (17) placed on a base (4) in such a way that it is movable in all directions in a horizontal plane during the positioning phase of the spindle (6), a spherical ball (13) freely rotatably mounted in the ball holder (17), and a substantially vertical quill (10) that is axially movable within the ball (13) and supports the tool driving spindle. Said spherical ball (13) has weights that balance the weight of the means for translating the quill (10) and that of said quill and said spindle when the latter are in the lower aligned position, so that said weights return the centre of gravity (G) of the assembly substantially into alignment with the axis (x, x') of the quill (10), whereas the electrical means (28, 29) for driving the spindle (6) are arranged in the quill (10) and thus locate the centre of gravity thereof on said axis (x', x) and close to the centre (C) of the spherical ball (13) when said quill is in the lower aligned position. Furthermore, means for generating a planar air cushion between the base (4) and the ball holder (17) include jets (47) arranged in the base (4) opposite the ball holder (17) for feeding a film having a uniform thickness, and clamping means include nozzles (62) separate from the cushion-forming jets (47) and capable of being connected to a vacuum source.

Description

BACKGROUND OF THE INVENTION

The common axis alignment operation performed by the aforementioned type of angular and axial positioning device includes:

a pre-adjustment phase consisting of introducing said device over the processing of the intended valve seat by moving the adjustable support carrier along the machine tool bed,

- a phase of releasing means for blocking or clamping the corresponding elements of said device, a phase of shifting the housing relative to the spherical positioning core to the lowered operating position using a motorized or manually operated driving means provided with a manually inserted guide bar to facilitate insertion of the cutting tool into the valve guide , a common axis alignment phase, performed automatically using the rigidity of the guide / guide bar / cutting tool assembly to bring the longitudinal axis of the spindle into coincidence with the valve guide axis by moving the individual elements of said alignment device to the common axis and finally the phase locking (or clamping) in the set position.

Depending on the type of embodiment of said angular and axial positioning device, the spherical positioning core is coupled by means such as WO-A-80/01365 with means such as either pneumatic support described in the patent application by electromagnetic support described in the patent application

EP-A-0263766 or, in a simpler embodiment, the spherical positioning core is supported by a spherical seat, the surface of which is provided with a layer of material with a high sliding coefficient, and may, after releasing the locking means in the set position, in order to angularly position the sleeve and thus the longitudinal axis of the spindle are freely displaced.

In the case of a common-axis alignment device on machine tools for precision grinding of valve seats requiring the use of high drive torque, an electric motor is associated with the spindle by means of transmission means, fixedly mounted on the adjustable support beam which these transmission means even , described in patent application FR-A-2501094, which include a counter telescopic shaft, each end of which is provided with an articulated coupling, for copying all angular displacements which include the angular positioning of the spindle, prevent said displacement and require substantial force for their operation adversely affects search and positioning accuracy during the auto-alignment phase.

On the above, it must be added that, after the guide rod has been inserted into the bore of the valve guide and the desired spindle alignment is ensured, by relocating the guide rod, by relocating its angular positioning and in a horizontal plane, this takes place in any direction horizontally relative to spindle, which requires the necessary relocation of all the elements and means provided in the device. In the above-mentioned machine tools, the mass to be displaced for alignment in a common axis has a size of the order of 140 kg. As a result of the inertia of said masses and friction between the guide means, the occurrence of a cross-feed occurs, which results in increased friction due to unfavorable forces resulting from the displacement of the spindle not parallel to the cross-feed. the reaction forces exerted by the crossing of the guide rod act in the opposite direction, and that this rod may remain angularly deflected, and therefore it is not possible to indicate the axis of coincidence with the valve guide. Consequently, the inaccuracy of concentration is several hundredths of a millimeter. completely unacceptable.

condition, relative to the spindles into each other

The above drawbacks become even more complicated when using a common axis positioning device of the type described above in combination with a machine tool for precision grinding of valve seats of multi-valve cylinder heads, such as those cylinder heads having four valves per cylinder with a valve guide diameter smaller or equal to 7 mm, as the guide rod used, which in this case has a diameter of the order of 4 mm, is more flexible and more capable of retaining residual stresses, which constitutes a risk of undesirable permanent deformation or, as in the case described in EP-A -0478478, it is necessary to position the guiding which contact rod to complement, for example, to determine the axis of the housing allow, sensing, longitudinal means, by means of a base valve.

geometric position

In fact, in the above cases, and although the freedom of movement of the spherical positioning core is given and secured by the spatial arrangement of the device, the acting inertia and various resistive forces adversely eliminate the horizontal displacement itself, both spindle adjustment and displacement during oval touch sensing. the inner face of the straightening bore.

Patent application FR-A-2501094 discloses a common axis alignment device in which a spherical hinge member is supported by an adjustable body that can slide into a common boundary clamp during the alignment phase and which is locked by the actuator after alignment and adjustment .

axis, given the fixed shift in the horizontal design required

This device, while eliminating the reactions due to adverse forces occurring during the crossed movements, on the other hand, increases the amount of friction which, in combination with the stress applied to the spindle of the articulated clutch, by means of which the spindle is coupled to the driving means such inaccuracies during the adjustment of the desired position that it is unusable to accurately machine the valve seats of the multi-valve cylinder heads.

In addition, actuation of the means for blocking the adjusting body, when set to the desired alignment position, may cause it to be displaced so that its position is not parallel to the desired position as shown in FIG. 8 of the accompanying drawings, due to its positioning off the axis with respect to the spindle axis and the bending of the spindle causing it to tilt against the guide rod guide housed in the valve guide.

These various disadvantages are further exacerbated in the alignment device, whose spacer sleeve is supported in the common axis by the plane flexible air layers during the alignment phase.

This is due to the fact that during the alignment phase to the common axis different masses of the device, in particular masses of translational means mainly for rotary spindle drive, but masses of means for driving the spindle into displacement, cause angular tilting of the spindle / ball positioning core / sleeve. the wedge shape of the planar flexible air layers and the resulting angular inclination of the sleeve relative to the support slide during the clamping phase. As a result, the alignment of the spindle with the valve guide relative to the set position defined during the alignment phase to the common axis is violated, resulting in inaccuracies during precision machining.

SUMMARY OF THE INVENTION

It is an object and object of the present invention to provide a common axis alignment device which, by its structural arrangement, removes the above-mentioned drawbacks by reducing system inertia and eliminating to the maximum extent the physical and mechanical stresses and stresses resulting from transmission of motional energies to drive the spindle; performing translational translation of the spindle with respect to the sleeve and the support slide.

Accordingly, the construction of the device according to the present invention is characterized in that the spherical positioning core is provided with balancing masses which, by balancing the masses of the means for driving the bushing to translational displacement and the masses of the bushing and spindle in the adjusted lowered working position. substantially on the axis of the housing, wherein said housing comprises electrical means for driving the spindle in such a manner that when the housing is brought into the set lowered operating position, the center of gravity is located on the axis and in close proximity to the center of rotation of the spherical positioning core; that the means for forming a planar flexible layer between the support slide and the end face of the sleeve comprises nozzles disposed on the end face of the support slide opposite the end face of the sleeve and adapted to form a flexible layer of uniform thickness; and that the clamping means comprises widened orifice channels different from the nozzle channels and adapted to be connected to a vacuum source.

reduces mass, and thus also reduces

As a result of this design, the spindle can be positioned and aligned with the valve guide to a common axis after releasing the means for rigidly clamping the spherical positioning core, and the angular positioning of the spindle is not limited by the directional force generated by the mechanical transmission. In addition, the removal of said mechanical transmission significantly designed to relocate the inertia of the system. In addition, the arrangement of said masses in the interior of the housing, balancing the masses of the entire assembly, positioning the center of gravity on the axial axis of the housing and thus the center of rotation of the spherical positioning core, and supporting the sleeve using a flexible air layer of uniform thickness eliminate all external stresses and stresses such that the sleeve can be completely freely displaced in the horizontal plane, and during the automatic alignment of the spindle alignment to the common axis, no stress or stress is generated in response to the insertion of the guide rod into the valve guide.

In a similar manner, said design favorably supports the displacement of the proposed device and eliminates any undesired stresses and stresses during the touch-sensing drilling operation by guiding the guide rod.

Finally, the balancing of the sleeve / spherical positioning core / sleeve assembly in combination with the formation of a planar flexible air layer of uniform thickness ensures and guarantees parallelism between the lower face of the sleeve and the upper face of the support slide and eliminates any possibility of being clamped. the angular offset of the sleeve with respect to the support slide and for this reason as well as any changes in the exact alignment and alignment achieved in the previous phase.

It is clear from this that the center of gravity of the assembly, the spatial distribution of the means for driving the spindle motor, the formation of a planar flexible air layer of uniform thickness, and vacuum clamping will all achieve the desired goal of accurately aligning the spindle with the valve guide.

According to one embodiment of the present invention, the piston's return stroke, which, as a result of interaction with the lower spherical seat of the sleeve, blocks the movement of the spherical positioning core, is delimited by three adjustable spacing stops screwed into the threaded bore passages in the fixed flange of the sleeve. spaced at 180 °.

Accordingly, during the alignment phase to a common axis, the thickness of the resilient air layer formed between the lower spherical seat and the lower spherical support surface of the spherical positioning core is calibrated by a resilient air pad between the upper spherical support surface of the spherical positioning core and the upper spherical since the upper said spherical seat, by supporting the set-up positioning piston with its rear face on three limiting stops, exhibits a precise adjustment. As a result, any lateral displacement of the spherical positioning core is completely eliminated and the desired accuracy of the spindle alignment operation with the valve guide to the common axis is achieved.

According to a further embodiment of the present invention, the electric motor expediently arranged in the housing is supplied with energy by an external circuit comprising a removable frictional contact interacting with contact elements disposed on the periphery of the spherical positioning core on both sides with respect to its center plane and forming part of the inner a circuit arranged in said spherical positioning core.

In view of the above, during the alignment phase to the common axis or the touch sensing phase, the frictional contact moves to the retracted zero position and thus releases the spherical positioning core for free movement. As a result, the spherical positioning core is released from all, even minimal in terms of size, stress and strain, of operating means for driving the spindle electric motor. When set to the corresponding aligned position, the friction contact is moved to the operating position by displacing it in the radial direction towards the spherical positioning core to drive the electric motor.

According to a preferred embodiment of the present invention, each of the nozzles arranged in the support beam for forming the flexible air layer supporting the sleeve includes, as part of the compressed air supply circuit, a regulating member for adjusting the flow rate of compressed air to achieve a flexible air inlet of uniform thickness.

This arrangement makes it easy to regulate the power supply of any nozzle of the nozzle assembly in order to achieve a flexible air layer of uniform thickness and ensures, between the alignment phase to the common axis and the clamping phase, and with respect to the center of gravity in the spherical positioning core, on the carrier support.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the device of the present invention will be apparent from the following detailed description of several exemplary embodiments thereof in combination with the accompanying drawing, wherein:

Fig. 1 is a schematic axonometric view in partial view showing a device according to the present invention adapted to clamp a cutting tool in a positioning and alignment phase in a common axis;

Fig. S is a partial cross-sectional side view showing a first embodiment of a device according to the present invention having a hand wheel for moving the housing;

Fig. 3 is a front view of the device of the present invention shown in FIG. WITH;

Fig. 4 is a partial cross-sectional side view showing another embodiment of a device according to the present invention;

Fig. 5 is a longitudinal sectional view showing a first embodiment of a housing that includes a motorized spindle;

Fig. 6 is an enlarged partial cross-sectional view. showing an alternative embodiment of the means for supplying power to the spindle motor;

Fig. 7 is a cross-sectional side view showing an alternative embodiment of mechanical clamping means;

Fig. 8 is a schematic illustration, in side elevation and on an enlarged scale, illustrating, for example, an incorrectly unwanted adjustment of the cutting tool to the working position resulting from

1S of mechanical clamping when applied to a flexible carrier air layer having an uneven thickness.

DETAILED DESCRIPTION OF THE INVENTION

In the accompanying drawings, the reference numeral 7 represents the cylinder head (see FIG. 1) and the reference numeral 2 generally represents a machine tool bed provided with a longitudinal slide guide 3 for pre-adjusting the adjustable support slide 4, guided by rolling elements 5. The spindle 6 is provided with a tool holder 7 into which a cutting tool 8 can be retracted and clamped by means of a guide rod 9. Said spindle is mounted so that it can rotate freely in the sleeve 10. The sleeve 10 is fixedly mounted to prevent rotation. and arranged in such a way that the slide can slide in the inner bore 12 of the spherical positioning core 13, showing the possibility of displacement due to the action of a motor or mechanical type device. Said device, see FIG. 2 of the accompanying drawings consists of a gear 11a. driven by the handwheel 11b and engaged with the toothed rack 11c. The transfer guide of the housing 10 is complemented by a lower support bearing 14 mounted on the underside of the spherical positioning core 13 through which the shaft 11d extends. connecting the handwheel 11b to the gearwheel 11a

Reference numeral 73 represents a pneumatic equilibrium strut disposed between a spherical positioning core 13 and a support beam 74 coupled to a housing 10, the purpose being, on the one hand, the accumulation of the housing 10 downwards, which moves the housing backward to keep the housing out of manual operation.

the energy during displacement is then utilized at the top and, in addition, at the corresponding position during the wheel 11b out of operation.

The spherical positioning core 15 is rigidly mounted against rotation about the axis of the housing 10 by means not shown in the accompanying drawings, which include a lower spherical abutment surface 15 supported by a spherical cup-shaped recess 16 formed in a sleeve 17 disposed relative to one another. The upper spherical abutment surface 18 of the spherical positioning core 15 is designed to interact with a corresponding cup-shaped concave abutment surface of the clamping means, in this embodiment consisting of a piston 19 which is adapted to be vertically displaced within the interior of the sleeve 17. of the illustrated embodiments of the claimed device, said piston 19 is moved in the clamping direction by clamping the spherical positioning core 13 under the action of a pneumatic circuit through which the chamber SO defined by the The compressed air introduces compressed air through the front face of said piston 19 and the fixedly fixed annular flange SS of the sleeve 17.

The above means correspond to those described in the international application

WO-A-80/01365 and will therefore not be described in further detail. Accordingly, it must be noted that in cases where the device is in a common alignment position or in a touch sensing position, the SO chamber in order to release the piston 19 from the clamping clamp, it is vented to the ambient atmosphere and compressed air is introduced through a channel S1 into the main chamber 23 formed between the spherical positioning core 13 and the inner wall of the sleeve 17 so as to support the core 15 in the vertical direction and, on the other hand, forms two flexible air layers between the spherical support surfaces 15 and 18 of said core 13 and their corresponding seat 16 and the cup-shaped concave support surface of the piston.

The aforementioned construction constitutes means which allow angular positioning of the spherical positioning core 13 and the spindle 6 shown in FIG. 1 in order to align the axis X'-X of the spindle 6 with the longitudinal axis of the valve guide 24 in which the guide rod 9 is arranged and coaxially arranged with the valve seat 25 to be machined into a common axis.

As shown in greater detail and on an enlarged scale in FIG. 5 of the accompanying drawings, a housing 10 comprising, in order to guide and rotatably mount the spindle 6 of the bearing 26 and 27, furthermore constitutes a housing of an electric motor 28 and means 29 for transmitting motional energy between the output driven shaft 50 and the corresponding end of the spindle 6. in the accompanying drawing of the illustrated embodiment, said energy means from the reduction means comprise 89 for transmitting a gear transmission, these may be any suitable arrangement for said purpose so as not to depart from the claimed scope of the present invention.

As a result of this, the center of gravity G of the machining head formed by the sleeve 10 and the elements carrying the sleeve 10 is located on the axis of the X-Spindle 6.

In addition, and in accordance with another feature of the present invention, the spherical positioning core 15 is provided with balancing masses 15a and 15b. which serve to balance the masses of the means 11a to 11d for bringing the housing 10 and the spindle 6 when the latter two elements are in a position in which they are arranged in a common axis and called the lowered working position, into a translational translation downwards. Such balancing is intended for the purpose of bringing the design to the axis for the purpose of eliminating the unwanted torque or torque during the movement of the spindle into the alignment phase on a common axis. In addition, the various elements are arranged in relation to each other in such a way that, when the sleeve is in the alignment position in a common axis, i.e. in the so-called lowered operating position allowing the guide rod 9 to be inserted into the valve guide 84, in close proximity to the pivot center C of the spherical positioning core 15, as seen in FIG. 1 of the accompanying drawings.

the center of gravity of the described X'-X housing 10 and making possible

According to FIG. With reference to the accompanying drawings, the electrical motor 88 supplies the required energy via an axially arranged connection 58, from which a flexible lead 55 protrudes from the end, which is wound into a helix and secured at its upper end to a bracket arm 54 arranged and supported. Due to this arrangement, the flexible lead cord exerts a very low stress on the machining head, which is not capable of limiting or obstructing the movement by varying movements during the alignment phase to a common axis.

Fig. 8 of the accompanying drawings clearly shows that due to this spatial arrangement, the machining head is not loaded by any of the transmission devices, and that the result of the angular positioning of the spindle 6 is completely independent of all voltages that are inherent in the operation of such transmission devices. it applies to displacements in the horizontal plane, provided that these displacements, in no way loaded by the inertia of the motor, and the movement of the intermediary transmission devices are initially carried out without applying a substantial initial force and subsequently freely without any resistance.

The sleeve 12, which as a whole has a cylindrical shape, is provided with a cylindrical flange 55, the lower face 55a of which bears directly on the upper face of the adjustable support support 4. Said flange may be provided by itself or arranged in a cylindrical cover 56 attached to the support The slide 4 and comprising an inner bore 57 whose diameter is greater than the outer diameter of the cylindrical flange 35 so as to form a radial clearance between the inner wall of the cylindrical cover 56 and the cylindrical flange 55. Similarly, the upper wall 38 of the cylindrical cover also has a certain distance from the upper face of the cylindrical flange 55 so that the free and in some way unrestricted movement of the flange. Said upper wall 58 has an axial bore 39 whose diameter is greater than the outer diameter of the cylindrical body of the sleeve 17. whereas the support beam 4 has a bore 40 whose diameter is larger than the outer diameter of the lower support bearing 14 extending through said bore and fixedly. coupled to a spherical positioning core 13.

From this, it will be readily understood that, due to such a spatial arrangement, the sleeve 17 and thus the spherical positioning core 13, the sleeve 10 and the direction are displaced along the longitudinal axis of the cylindrical attached drawing spindle 6 can radially all directions with respect to the bodies FIG. 1 of the documentation indicated by the arrows 31, as well as to all sides with respect to the theoretical longitudinal axis of the cylindrical cover 36, said facts being valid in the interior space defined explicitly by the radial clearance between the cylindrical flange 35 and the inner bore 37 of the cylindrical cover 36.

This arrangement eliminates all the drawbacks and disadvantages which are an essential part in the application of intersecting sliding movements with further movements, one direction of which is fixed by limitation of the mechanical nature, and allows, in the case of a valve seat machine, the application of said displacement movements of the support carriage 4 only for pre-positioning the machining head with respect to the region of the cylinder head to be machined (see FIG. 1 of the accompanying drawing).

In order to assist said displacement and as can be seen from FIG. With reference to the drawings, the region of the support slide 4, located below the cylinder cover 36 and in particular the area in which the cylindrical flange 35 is displaced, passes through it a channel 41 communicating with the fluid circuit 48 of a pressurized gas supply 49, in particular compressed air. In this state, a flexible air layer 71 is formed between the cylindrical flange 35 and the support 4 by means of compressed air channels 41, said air layer carrying the sleeve 17 and all of the structural elements disposed therein and facilitating and its displacement relative to the carrier 4.

Such an arrangement reduces the friction and, in combination with the two flexible air layers, favorably affecting the angular orientation of the spherical positioning core 13, explicitly allows, during the alignment phase to the common axis, complete release of the machining head from any stresses and stresses, and during touch sensing, allows the touch sensor assembly to be released from any force, thereby facilitating said operation.

It should be noted and emphasized that during said touch-reading operation, the detected data is recorded by mechanical or electronic means whose construction, since it is not related to the subject of the present invention, will not be described in more detail below for obvious reasons.

Preferably, and as can be seen from FIG. 6 of the attached drawing. Three bolts 75, arranged parallel to the X'-X axis and at an ISO ° spacing relative to each other, form the limit stops of the piston 19 through the fixed annular flange of the SS sleeve 17. the chamber SO is vented to the ambient atmosphere and the compressed air is introduced into the main chamber 83, the rear face of the piston 19 at its return stroke engages the three limiting stops 75 so that they are in the respective, precisely adjusted position. for the spherical seat 19a of the piston 19, the exact definition of the thickness of the flexible air layer between the spherical seat 19a and the upper spherical abutment surface 18 of the spherical positioning core 13 is achieved by said fact. and at the same time At the same time, a precise delimitation of the thickness of the flexible air layer between the lower spherical support surface 15 of the spherical positioning core 13 and the seat 16 of the holder 17. This arrangement allows to avoid any undesired positioning of the spherical positioning core 13 outside the axes. leveling operations

SO to the common axis and consequently adversely affect the clamping accuracy.

After the alignment or touch probe alignment operation has been completed and the spindle adjustment position is definitive, the spindle is locked in this position and secured by clamping. The spherical positioning core 15 is thus fixed by means of pneumatic displacement of the piston 19 in the sleeve 17.

In order to prevent the possibility of bringing the cylindrical flange 55 into position 55d. in which it rests on the support slide 4, that is to say the eccentric positioning off the axes during clamping, as can be seen from FIG. 8 of the accompanying drawings caused by the deflection of the sleeve 17 off-center and the deflection of the axis X'-X of the spindle 6 about a point located in the bearing of the guide rod 9 in the valve guide 84 by an angle. With respect to its position defined by the alignment operation with the axis of the valve guide, means are provided on the one hand for forming a resilient air layer between the support slide 4 and the sleeve 17 with a constant thickness, and on the other hand for providing this layer.

Said means for forming a flexible air layer of constant thickness, as can be seen from FIG. 6 of the accompanying drawings, consist of nozzles 47 arranged at the outlet of the channels 41, which are coupled to the regulating member 48 to supply them. Thus, it is possible, through angular

S1 of positioning the center of gravity on the X'-X axis of the assembly comprising the sleeve, the spherical positioning core and the sleeve, and adjusting said nozzles to achieve a planar flexible air layer 71 of uniform thickness and while clamping the sleeve displacement parallel to each other.

Said means for eliminating the flexible air layer 71 and thus for clamping, as can be seen from FIG. S and 6 of the accompanying drawings consist of widened orifices 68 which, unlike nozzles 41 provided with nozzles 47, are connected via duct 65 to a directional control valve 64 which either disables them or brings them into flow communication with a vacuum source of 60.

In this arrangement, a manual or electromagnetically controlled directional control valve 61 is actuated after a common axis alignment operation to interrupt the supply of 4x9 compressed air and bring the air layer 71 into fluid communication with the ambient atmosphere 59. Due to the uniform thickness of the flexible air The layer 17 and its small size, in the order of several hundredths of a millimeter, sink and engage the sleeve 17 parallel to the corresponding bearing surface, following the axis of the spindle, on the guide, secured by sliding the guide rod 9 in the valve guide 84. As soon as the sleeve 17 bears on the support, a directional 64 is actuated by means of which a control valve is actuated behind the support 4 in order to create a vacuum for clamping locking.

The SS sleeves 17 on the support beam 4 and its gripping in this reached position bring the widened orifices 68 into fluid communication with the vacuum source 60.

Said clamping is generally sufficient to transfer the generally occurring cutting forces. However, this arrangement can also be supplemented by mechanical clamping means.

In FIG. S and 4 of the accompanying drawings, these mechanical clamping means consist of a plurality of pneumatic actuators 45 equally spaced around a sleeve 17 whose base bodies are fixed to the upper wall 58 of the cylindrical cover 56 while their rod-shaped actuators extend through said upper wall 38 into contact with the upper face of the cylindrical flange 55.

According to an alternative embodiment shown in FIG. 7 of the accompanying drawings, said actuators 65, for example three, are equally spaced apart from each other at a span of 180 ° about the longitudinal and vertical axes of the cylindrical cover 36 arranged below the support slide 4 to which their base bodies 66 are attached. said actuators 65 are provided with cylindrical necks 68 through which an axial connecting rod 69 extends. Each of these connecting rods 69, whose upper ends are supported by a screw connection in the cylindrical flange 55c of the sleeve 17 passes through a bore 70 formed in the support beam 4, a neck 68 with a clearance that corresponds to the clearance for displacing the cylindrical flange 55c within the interior of the cylindrical cover 36. Finally, the lower end of the axial connecting rod 69 extending behind and out of the cylindrical neck 68 is coupled to a shim 7xS adapted to and capable of carrying the axial pressure of the cylinder throat 68 of the piston 67th

Thus, when the cylindrical flange 55c rests on the resilient air layer 71, said clamping actuators 65 do not prevent its movement, while during clamping the clamping force is transmitted directly to this flange 55c via axial connecting rods 69.

According to the construction of the proposed device shown in FIG. 4, the device may differ from the embodiment described above in that the pivoting center C of the ball arranged substantially in the front surface of the support positioning core 13 is in the horizontal plane H of the upper slide 4. As a result, the upper part of the cylindrical bodies 17a. arranged above the support slide 4 extends into the cylindrical flange 55c. while its lower part passes through the bore 46 of the support slide 4.

Due to this arrangement, the angular positioning of the spindle is independent of its position in the horizontal plane, further improving the conditions for alignment to the common axis or touch sensing.

Finally, in order to remove even very minor obstacles or shortcomings that may be

S4 caused by the flexible lead 33 for powering the electric motor 38, the power supply arrangement can be replaced by the arrangement shown in FIG. 6 of the accompanying drawings, the practical location of which is located in the substantially horizontal center plane of the spherical positioning core 13. The power supply arrangement comprises an inner circuit comprising:

- longitudinal strips SO formed of an electrically conductive material arranged on and embedded in the outer front surface of the housing 10 and which are electrically connected to the power supply circuit of the electric motor expediently arranged in the interior of the housing,

- contact contacts 53 extending from the axial inner bore 13 of the spherical positioning core 13 and adapted to be in contact with the longitudinal strips 50, and

corresponding sections of circumferential strips 55 arranged on and embedded in the outer surface of the spherical positioning core, equally spaced on both sides of its horizontal center plane and electrically connected to the contact contacts 53 by means of a guide 54;

and an outer circuit terminated by a frictional contact

55th

Said frictional contact is provided with spring contact contacts 56 which are electrically connected to an external circuit. This frictional contact 55 is loosely supported on means adapted to move the frictional contact between an operating position in which its spring-loaded contact contacts 56 are in contact with corresponding sections of the peripheral strips 53 and a retracted zero position in which contact contacts are indicated. remote from the corresponding peripheral strip sections. In the embodiment described above, the frictional contact bearing means constitutes an actuator 57 whose base body is fixedly mounted on the outer surface of the sleeve 17, while its rod-shaped actuator extends across the wall to engage the frictional contact via a ball joint 78. sleeves 17.

It should be understood that during the alignment phase to the common axis, the friction contact 55 is moved to the retracted zero position to completely release the spherical positioning core 13 and that after the alignment phase has been carried out and the cutting tool is brought into the desired set position it moves to its operating position so that its spring-loaded contact contacts 56 are in contact with the corresponding sections of the peripheral strips 53. This is of great importance because of the angular phase reached during the alignment phase positioning the spherical positioning core 13 in the range of a slight angle of magnitude ranging from 1 to 5 ", any variations or deviations in the relative positions of the front surfaces of the contact contacts 56 and the corresponding sections of the peripheral strips 55 are easily compensated by means vacieho arrangement

friction contact 55 and resilient fit of its contact contacts 56.

From the foregoing, it should be apparent to those skilled in the art that the device of the present invention, by its arrangement, eliminates and releases angular positioning means and means for adjusting the vertical position of the longitudinal axis of the spindle from any external stresses and strains, , reduces the forces applied and allows more accurate alignment and alignment to the common axis, since, due to the arrangement described above, it is quite common to achieve alignment with an accuracy of in the order of 0.08 mm. Moreover, said device exhibits very favorable conditions for touch sensing, which can thus be carried out manually.

Furthermore, it must be clear from the foregoing that, even if it does not exhibit the use of an external transmission of the type equipped with a telescopic shaft and two articulated couplings arranged between the motor and the spindle, it allows an increase in speed to achieve the required machining seats and spindle rotation at a speed of guiding small valves,

Claims (8)

PATENT CLAIMS A device for aligning a longitudinal axis of a cutting tool with a valve guide axis to a common axis, in which, on the one hand, the cutting tool (8), fixed in the spindle (6), is coupled to a coaxially arranged guide rod (9); on the other hand, the compensating means comprise: - an adjustable support slide (4) adapted to be displaced in a horizontal plane on a fixed bed (S), at least in the longitudinal direction; - a sleeve (17) disposed on said support beam (4) and adapted to be displaced in all directions in a horizontal plane during the spindle positioning phase and after release of the clamping means by a planar flexible air layer formed between the sleeve face and support beam (4) ; - a spherical positioning core (13) housed in a seat (16) of the spacer barrel (17) and adapted to rotate freely during the positioning phase of the spindle and after release of the clamping means; and - a substantially vertical housing (10) which can be moved axially in the spherical positioning core (13), characterized in that the spherical positioning core (13) is provided with balancing masses which, by balancing the masses of the means for driving the casing (10) the translational displacement and the masses of the housing and the spindle located in the set lowered operating position bring the center of gravity (G) of the assembly substantially on the axis (X-X ') of the housing (10), the electrical means (88) disposed in said housing (10) . S8 89) for driving the spindle (6) in such a way that, when the sleeve is brought into the set lowered working position of the center of gravity (G), the center is on the axis (X-X ') and in close proximity to the center of rotation (C) of the ball positioning core (13); that the means for forming a planar elastic layer between the support slide (4) and the end face of the sleeve (17) include nozzles (47) disposed on the front face of the support slide (4) opposite the end face of the sleeve (17) and adapted to form a resilient layers of uniform thickness; and that the clamping means comprises widened orifices (68) different from the nozzle channels (47) and adapted to be connected to a vacuum source. Common-axis alignment device according to claim 1, characterized in that the back-release release of the piston (19) as a result of the interaction with the lower spherical seat (16) of the sleeve (17) blocks the movement of the spherical positioning core (13). is defined by three adjustable limit stops (75) screwed into the threaded bores in the fixed flange (88) of the sleeve (17) and spaced apart from each other at an ISO spacing ”. Common axis alignment device according to claim 1, characterized in that the electric motor (88) expediently arranged in the housing (10) is supplied with energy by means of a flexible lead (33) wound into a helix whose upper end is attached to a bracket arm (34) extending from the body of the sleeve (17), while its lower end is coupled to a connector 33 which is arranged axially and substantially on the longitudinal axis of said housing (10). Common axis alignment device according to claim 1, characterized in that the electric motor (38) expediently arranged in the housing (10) is supplied with energy by an external circuit, which comprises a removable friction contact (55) interacting with with contact elements disposed on the periphery of the spherical positioning core (13) on both sides with respect to its median plane and forming part of an inner circuit arranged in said spherical positioning core (13). Common axis alignment device according to claim 4, characterized in that the electric motor (38) is supplied with energy, on the one hand, by means of electrically conductive longitudinal strips (50) arranged and embedded in the outer face of the housing (10). which are electrically coupled to contact contacts (53) extending from the axial inner bore (13) of the spherical positioning core (13), the contact contacts (53) being electrically connected to corresponding sections of the peripheral strips (53) by means of a guide (54) arranged on and recessed in the outer surface of the spherical positioning core and equally spaced on both sides of its horizontal center plane, and, on the other hand, by a frictional contact provided with spring contact contacts (56) adapted to interact with corresponding sections of circumferential strips ( 53), carrier arranged on the sleeve body (17) and with respect to the sleeve body (17) movable between an operating position in which its spring contact contacts (56) are electrically coupled to corresponding sections of the peripheral strips (53) and a retracted zero position in which the contact contacts (56) remote from the corresponding peripheral strip sections. A common axis alignment device according to claims 4 and 5, characterized in that the friction contact (55) is loosely mounted on the free end of the connecting rod of the fluid actuator (57), the base body of which is fixedly coupled to the sleeve (17). a spherical positioning core (13) is provided. Common axis alignment device according to claim 1, characterized in that each of said nozzles (47) arranged in the support beam (4) for forming a flexible air layer supporting the sleeve (17) comprises as part of a supply circuit a compressed an air regulating member (48) for adjusting the flow rate of compressed air to provide a flexible air layer of uniform thickness. Common axis alignment device according to claim 1, characterized in that the sleeve (17) is provided with a peripheral flange (35c) through which it comes into contact with the support slide (4) and the peripheral flange (35c) is coupled. with mechanical clamping means consisting of actuators (65) arranged below the support slide (4) to which their base bodies (66) are attached while their connecting rods (69) are connected to a peripheral flange (35c), each of said connecting rods (69) passes through a bore (70) formed in the support beam 4 and the cylindrical neck (68) of the piston (67) of the respective radial clearance actuator and includes a spacer (7S) disposed at its lower end for transmitting the axial pressure of the cylindrical neck (68) of the piston (67) during the clamping phase. A common axis alignment device according to claim 1, characterized in that the center of rotation (C) of the spherical positioning core (13) is defined in the horizontal plane (H) by the face of the sleeve (17) resting on the support slide (13). 4).