FR2666532A1 - Device for positioning a machining station, in terms of angle and in terms of distance - Google Patents

Abstract

Device for positioning a machining station (1), in terms of angle and in terms of distance, with respect to a vertical reference direction (2), comprising a framework (3), an orientation sector (5) mounted so that it can move in terms of rotation on the framework about an axis of orientation (6) perpendicular to the reference direction, a carriage (7) mounted so that it can move in terms of translation on the orientation sector (5), the machining station being mounted on the carriage, characterised in that a system for balancing out the masses interacts with the equipment composed at least by the orientation sector (5), the carriage (7), and the machining station (1), and includes two complementary return members, namely: - a first member (10) consisting of a first torsional return means between the framework (3) and the orientation sector (5), - a second return member (11) comprising an arm (12) mounted perpendicularly in terms of rotation about the orientation axis (6), a kinematic link (13) between the carriage (7) and the arm, and a second torsional return means (14), located along the orientation axis (6) between the framework and the perpendicular arm.

Description

DEVICE FOR ANGULAR AND DISTANCE POSITIONING
A MACHINING STATION
The present invention relates to a device for supporting and positioning angularly and in distance a machining station, relative to a vertical or substantially vertical reference direction.

 To this end, there is already known a device comprising a rigid frame comprising a panel extending in the reference direction and perpendicular to the latter, an orientation sector, of extension parallel to the panel, mounted movable in rotation on the frame. around an orientation axis, the latter being perpendicular to the aforementioned reference direction, a carriage movable in translation on the orientation sector, along a translation axis orthogonal to the aforementioned orientation axis. The machining station is then mounted on the carriage, and can thus be moved both in rotation around the orientation axis, and in translation relative to the carriage. Means for controlling the sector in orientation and the carriage in translation are provided for positioning the machining station, angularly and at a distance from the vertical reference direction.

 Taking into account the mass represented by the crew constituted by the sector, the carriage and the machining station, and taking into account the displacement of the center of gravity of this crew as a function of the movements of the orientation sector and of the carriage, in practice turns out to be relatively difficult to control with good precision the angular and distance orientation of the machining tool, with respect to the reference direction.

 The present invention therefore relates to means making it possible at the same time to limit or even neutralize the influence of the mass or masses of the crew supporting the machining station, and to simplify the control of the latter.

In accordance with the invention, a mass balancing system is first provided, cooperating with the aforementioned crew, and comprising two complementary return members, namely
- A first member consisting of a first torsion return means, arranged along the orientation axis, between the frame and the orientation sector, bandaged or loaded in the rest position of the crew to exert a first torque recall, which balances at least partly, if not entirely, the drive torque by the weight of the crew;
- a second return member comprising an arm mounted perpendicularly in rotation about the orientation axis, a kinematic connection transform the translation of the carriage into rotation of the arm, or vice versa, and a second torsion return means, arranged along the orientation axis, between the frame and the aforementioned perpendicular arm, this second return means being in a neutral position in the rest position of the crew, and being loaded by the translational movement of the carriage.

 As shown below, this balancing system makes it possible to obtain an almost neutral position of the crew, then allowing angular control with a minimum of stresses or restoring efforts.

As for the crew control, according to the invention, it comprises in combination
a locking member having at least two functions, one for stopping the carriage in translation, in which the orientation sector remains free to rotate, and the other for stopping the rotation of the aforementioned sector, in which the carriage remains free in translation
- A control member of the carriage associating the perpendicular arm and the kinematic connection defined above, and a mechanism for actuating the arm in rotation.

 Thanks to this system, according to the stop position controlled by the blocking member, it is possible, with the same control means, to actuate the sector in rotation, and / or in translation the carriage.

A device according to the present invention is now described in the more general context of a machine for rectifying valves of a heat engine, for example of an internal combustion engine, with reference to the accompanying drawings, in which
- Figure l shows a front view of a grinding machine incorporating a device according to the invention
- Figure 2 shows, with partial cutaway in vertical section, the machine shown in Figure l
- Figure 3 shows, schematically and for explanatory purposes, the positioning device according to the invention, incorporated by the machine shown in Figures l and 2
- Figure 4 shows in vertical section, according to the appropriate cutting planes, a locking member of the crew shown in Figure 3 and articulated in rotation about the axis 6 according to this figure.

 As regards the machine incorporating a device according to the invention, this makes it possible to correct a valve 33 comprising a rod 33a and a circular head 33b, the center of which is aligned with the axis of the rod 33a. This machine makes it possible to machine or rectify the rear face of the head 33b, adjacent to the rod 33a. To this end, the structure of this machine and its organization conform to those described in French patent application 90 06192 of May 7, 1990, in the name of the Applicant, and the content of which is incorporated herein, as of need.

Just remember that such a machine includes
- a rigid frame 3
a means 34 for supporting the rod 33a in rotation, mounted on the frame 3, comprising two supports 35 aligned in a vertical reference direction 2, arranged at a distance from each other, and respectively forming two glasses (not shown), of rotation of two intermediate journals of the valve stem; according to this arrangement, the means 34 for rotating support constitutes and determines a rigid reference frame for rotation of the valve stem 33a, merging with the vertical axis 2
a stop 36 for bearing in rotation on the valve stem, mounted by an appropriate screwing on the upper support 35
- A means 37 for driving the head 33b in rotation, by its front face opposite the face to be machined; this means 37 is disposed on the opposite side to the means 3 for rotating support of the rod 33a, and comprises a rotary drive member 38, for coupling in rotation with the aforementioned front face of the valve 33
- A machining station 1, mounted on the frame 3 in angular relation with the means 34 for rotating support, that is to say in angular relation with respect to the vertical direction 2; this machining station includes a tool making it possible to remove material or metal, in this case a circular grinding wheel 23, rotated by a motor axis 24.

As regards the device according to the invention, making it possible to support and position, both angularly and in distance, the machining station I, with respect to the vertical direction 2 of reference, and therefore with respect to the axis of valve 33, this essentially comprises the following elements
a rear panel 4 extending both along the reference direction, that is to say vertically, and perpendicular to the latter, that is to say horizontally
an orientation sector 5 of extension parallel to the aforementioned panel, having the general shape of a trapezoid with a circular edge, mounted movably in rotation on the frame 3 around a fixed axis 6, with a functional clearance allowing the flat sliding of sector 5 on #panel 4 ;; the axis of orientation 6 is perpendicular or orthogonal to the reference direction 2, while being fixed and mounted on the frame or rigid frame 3
- A carriage 7 mounted movable in translation on the orientation sector 5, the mobility in translation corresponding to a translation axis 8, orthogonal to the orientation axis 6
a plate 22 mounted movable in translation on the carriage 7, perpendicular to the direction of translation 8, this plate supporting the machining station 1, and more precisely the axis of rotation 24 with the circular grinding wheel 23.

 For the clarity of the description, the assembly articulated around the fixed axis of rotation 6, comprising the orientation sector 5, the carriage 7, and the machining station 1, as well as all the members introduced below supported by the aforementioned elements, will be designated under the common name "crew".

It follows from the preceding description that the machining station l has three degrees of freedom, namely
- a first degree in rotation around the axis 6, thanks to the orientation sector 5,
a second degree in translation in the direction 8 orthogonal to the axis 6,
- and a third degree in translation, perpendicular to direction 8.

 To control the machining station 1 according to all these degrees, different control means are provided, with the buttons or handwheels reported on the front face of the frame 3.

 A locking member 15, controlled in two positions by a button 75, has two distinct functions, one for translational stop of the carriage 7, in which the orientation sector 5 remains free to rotate about the axis 6 , and the other sector 5 rotation stop, in which the carriage 7 remains free in translation on the sector 5. As shown in Figure 4, the above functions are obtained by the arrangement and cooperation of the following bodies.

- A first blocking member consists of the following elements
- The panel 4 includes a recess 4b, having the shape of a circular sector centered on the axis 6, to accommodate the sector 5, while allowing its angular travel around the axis 6; the underside of the panel 4, at the level of the recess 4b, comprises a guide slide 4a, having the shape of an arc of a circle centered on the orientation axis 6
- The orientation sector 5 comprises two pins 20, passing through the slide 4a, with an appropriate functional clearance, arranged on either side of said sector along the circular path determined by the slide 4a
- The two studs 20 each have a blocking head 21, pneumatically actuable for example, disposed on the other side of the panel 4 relative to the sector 5, and movable according to the height of a stud 20; such a movement allows the two heads 21 to come into contact with the opposite face of the panel 4, to stop the rotation of the sector 5.

 Thanks to this arrangement, the sector 5 can be locked in rotation in a firm and rigid manner, according to a triangle determined as shown in FIG. 1, by the axis 6 and the two locking heads 21.

A second blocking member, ensuring the stop and the release of the carriage 7 relative to the sector 5, is obtained by the cooperation of the following means, shown only in FIG. 4
- The orientation sector 5 comprises a guide light Sa, having the shape of a straight line parallel to the direction of translation 8 of the carriage 7
- the carriage 7 comprises a stud 26 passing through the light Sa, with an appropriate functional clearance
a blocking head 27 is movable along the height of the stud, on the other side of the sector, in order to come reversibly into contact with the rear surface of said sector, and to stop the carriage 7 in translation.

 In addition, the control means of the articulated rotation on the axis 6 comprise a carriage control member 7 only, allowing separately to move the latter and pivot the sector 5 around the axis 6, respectively for one and the other of the two stop functions described above, chosen by the selector 75. This control member comprises an arm 12 mounted perpendicularly in rotation about the orientation axis 6, a kinematic link 13 transforming the translation of the carriage 7 in rotation of the arm 12, or vice versa, and a mechanism 16 for actuating the arm in rotation. As shown in FIG. 3, the kinematic connection 13 between the carriage 7 and the arm 12 comprises a crank pin 17 to the free end of said arm, a connecting rod 18 mounted or integral with the carriage 7, extending in the direction of the orientation axis 6, that is to say parallel to the latter, as well as a slide 19 disposed at the free end of the bie lle 18, engaged on the crank pin 17, and arranged perpendicular to the direction of translation 8.The actuating mechanism 16 in rotation of the arm comprises a shaft 37, mounted in rotation on the frame 3, on which are wired at one end, a control wheel 33, and on the other side of the sector 5, a pulley 38; the latter drives in rotation, by a belt 39, a wheel 40 mounted for rotation about the axis 6, free in translation relative to the latter over a certain range, the shaft 12 being wired and fixed in rotation on the pulley 40.

 As best shown in FIG. 2, the carriage 7 comprises a plate 28, mounted movable in translation in direction 8 on the sector 5, by means of appropriate slides 50, with on one side a support 29 of the plate 22, and therefore of the machining tool 1, this support being constituted by two parallel uprights with slides, and with on the other side, a support structure 30, extending opposite the support 29, passing through the panel 4 of the chassis 2, in an appropriate opening of the latter. A means 31 for rotating the tool or machining station 1, the axis of rotation 24 of which is parallel to the axis of translation 8 of the carriage, comprises a motor 51 supported by the support structure 30, driving the shaft 24 by a belt 52 and a pulley 53 cabled on the shaft 24.

 The system for balancing the masses of the crew articulated around the axis 6 comprises two complementary return members, shown diagrammatically in FIG. 3, as shown in FIG. 2.

 A first member 10 consists and is identified with a first torsion return means, or torsion spring 10, arranged along the orientation axis 6, between the frame 3 and the orientation sector 5. As shown in FIG. 2, this spring 10 comprises a movable strand 10a cabled in rotation on the sector 5, and a fixed strand 10b, taken in a plug 60, mounted, freely in translation but fixed in rotation, on a sleeve 4c, disposed at the rear of the panel 4. As already said, the spring 10 is bandaged or loaded at the start, that is to say in the rest position of the crew shown in FIG. 1 or 3, to exert a first torque return balancing at least partly the drive torque by the weight of said crew.

 A second return member 11 associates the arm 12 previously described, the kinematic connection 13 previously described, and comprises a second return means 14 in torsion or spring, arranged along the orientation axis 6, between the frame 3 and the perpendicular arm 12. As shown in FIG. 2, the spring 14 includes a fixed strand 14a cabled in rotation on the chassis 3, and a movable strand 14b cabled on the pulley 40, and therefore the arm 12.

In the rest position of the crew shown in Figure 3, the torsion spring 14 is in the neutral position, that is to say is neither loaded nor unloaded in torsion, and is arranged so as to load under the effect of the translational movement of the carriage 7, transmitted by the kinematic link 13.

 In terms of its principle, and from the schematic representation according to Figure 3, the action of the mass balancing system according to the invention can be explained as follows.

 FIG. 3 represents the positioning device at rest, that is to say in a horizontal orientation of the orientation sector 5 and in the extreme axial position of the carriage 7, that is to say close to the axis orientation 6. In this rest position, the center of gravity at rest of the crew constituted by sector 5, the carriage 7, the plate 22, the machining tool 1, and other ancillary members, is close of the orientation axis 6.

 In this rest position, as already said, the first return member, identified with the first torsion spring 10, is bandaged or already loaded, to exert a first return torque, partially balancing, if not all, the drive torque down, due to the weight of the crew exercising on their center of gravity at rest. As already said also, in this rest position, the second torsion spring 14 is in a neutral position, that is to say neither loaded nor unloaded in rotation.

 By actuating the locking member 15 in its stop function in translation of the carriage 7, the head 27 comes into contact with the sector 5 and stops in translation the carriage 7, while the two heads 21 are away from the adjacent face of the panel 4, and release the sector 5 in rotation about the axis 6, according to the relative positions shown in FIG. 4. By acting by the handwheel 33 on the mechanism 16 for actuating the arm 12 in rotation, the rotation of the latter is transformed by the kinematic link 13 into a rotation of the sector 5 with its carriage 7; the above-mentioned crew is made to pivot downwards, by reducing the driving torque under the effect of the weight, as the crew turns downwards, about the axis 6.

Simultaneously, the torsion spring 10 is discharged or discharged, correspondingly decreasing the first return torque in rotation of the crew upwards, which is in connection with the reduction in the driving torque due to the weight of the crew.

 By actuating the blocking member 15 in its sectoral rotation stop function 5, the head 27 is released from the sector 5 and releases the carriage 6 in translation, while the two heads 21 are locked against the adjacent face of the panel 4, and stop sector 5 in rotation. By acting on the same actuating mechanism 16, that is to say the one actuating arm 12 in rotation, then the rotation of the latter downwards is transformed by the link kinematics 13 in a translation of the carriage 7 towards the periphery of the sector 5; the carriage 7, the plate 22 and the machining head 1 are then moved towards the periphery of the sector 5, away from the axis of rotation 6. Correspondingly, it is moved in translation, in the direction 8 and towards the periphery of sector 5, the center of gravity of the crew articulated in rotation on the axis 6. This displacement of the center of gravity of the crew results, independently of the rotation of the crew previously discussed, an increase downward drive torque, all other things being equal, that is, equal to the weight of the crew.

 Furthermore, still under the effect of the translational movement of the carriage 7 towards the periphery of the sector 5, the torsion spring 14 is banded or loaded in rotation, by exerting a second return torque in rotation, distinct but completing the first return torque resulting from the torsion spring 10. The second return rotation torque of the spring 14 increases in the direction of movement in translation of the carriage 7, towards the periphery of the sector 7. This second couple is applied to the articulated assembly around the axis 6, by the kinematic link 13. In this way, the second return torque increases as the drive torque increases by the weight of the crew, only under the effect displacement in translation of its center of gravity.

 In total, the two components of the movement of the carriage 7, respectively in rotation by the sector 5 and in translation on the latter, respectively generate a downward drive torque, decreasing with rotation, and an overtorque, always of drive downward, increasing with translation. In correspondence, thanks to the means of the present invention, the drive torque is compensated at the outset by the rotation return torque of the spring 10, with a reduction of the latter as the crew rotates. . As for the overtorque, it is compensated in a complementary manner by the return torque in rotation of the spring 14, with an increase in the latter as the carriage travels. Of course, the setting of the torsion springs 10 and 14 can be chosen so as to compensate by the spring 10, almost all of the drive torque by the weight of the crew and the overtorque practically only by the spring 14. But the calibration of the springs 10 and 14, the one with respect to the other, may be such that the spring 14 is constrained in torsion, partly under the action of the weight of the crew, in addition to torsion under the effect of the overtorque previously discussed.

 Of course, the relative movements described above, of rotation of the crew and translation of the carriage 7, can be accomplished in the opposite direction, each as far as they are concerned, with an opposing restoring torque, also in the opposite direction, and the torsion spring 10 and torsion spring 14. In the same way, the relative movements described above can be obtained concomitantly, the action of the torsion springs 10 and 14 then being exerted at the same time, with respect to the couples and training overlays previously discussed.

 Thanks to the means of the present invention, described and explained above, permanent compensation is obtained for the different masses of the crew articulated in rotation about the axis 6, whatever the rotational position of the crew and the position in translation of the carriage 7. This compensation leads to a quasi-neutrality of the angular position of the entire crew, relative to the vertical axis 2, around the axis 6, despite the inertia or significant weight of the same crew . This quasi-neutrality then makes it possible, by the control mechanism 16, to adjust the angular position of the crew without effort or constraint, and this with very good precision, despite the masses set in motion.

Claims (11)

 1. Device for supporting and positioning angularly and in distance a station (I) for machining, relative to a direction (2) of vertical reference, comprising a rigid frame (3) comprising a panel (4) extending along the reference direction and perpendicularly to the latter, an orientation sector (5), of extension parallel to the panel, mounted to rotate on the frame around an axis (6) of orientation perpendicular to the reference direction, a carriage (7) mounted movable in translation on the orientation sector, along an axis (8) of translation orthogonal to the orientation axis, the machining station being mounted on the carriage, means (9) for control of the sector in orientation and of the carriage in translation, characterized in that a mass balancing system cooperates with the crew composed at least by the sector (5) of orientation, the carriage (7) and the station d 'machining (1), and comprises two complementary return members, s to have  - A first member (10) consisting of a first torsion return means, disposed along the axis (6) of orientation, between the frame (3) and the sector (5) of orientation, bandaged or loaded in the crew rest position for exerting a first restoring torque balancing at least partly the drive torque by the weight of said crew  a second return member (11) comprising an arm (12) mounted perpendicularly in rotation about the orientation axis (6), a kinematic connection (13) transforming the translation of the carriage (7) in rotation of the arm, or conversely, and a second torsion return means (14), arranged along the orientation axis (5), between the frame and the perpendicular arm, neutral in the rest position of the crew, and being loaded by the translational movement of the carriage.  2. Device for supporting and positioning angularly and at a distance a station (1) for machining, relative to a direction (2) of vertical reference, comprising a rigid frame (3) comprising a panel (4) extending along the reference direction and perpendicularly to the latter, an orientation sector (5), of extension parallel to the panel, mounted to rotate on the frame around an orientation axis (6) perpendicular to the reference direction, a carriage (7) mounted movable in translation on the orientation sector, along a translation axis orthogonal to the orientation axis, the machining station being mounted on the carriage, means (9) for controlling the sector in orientation and of the carriage in translation, characterized in that the control means report in combination, on the one hand, a locking member (15) having at least two functions, one for stopping the carriage in translation (7) , in which the orientation sector (5) remains free re in rotation, and the other sector rotation stop (5), in which the carriage (7) remains free in translation, and on the other hand a member (9) for controlling the carriage only, comprising an arm (12) mounted perpendicularly in rotation about the orientation axis (6), a kinematic link (13) transforming the translation of the carriage (7) into rotation of the arm (12), or vice versa, and a mechanism (16) rotating actuation of the arm.  3. Device according to claim 1 or 2, characterized in that the kinematic connection (13) between the carriage (7) and the arm (12) comprises a crank pin (17) at the free end of said arm, a connecting rod (18 ) mounted on the carriage, in the direction of the orientation axis (6), a slide (19) disposed at the free end of the connecting rod, engaged on the crank pin, and disposed perpendicular to the direction of translation (8 ).  4. Device according to claim 1 or 2, characterized in that the panel (4) comprises a guide slide (4a), having the shape of an arc of a circle centered on the orientation axis (6), and the orientation sector (5) comprises at least one stud (20) passing through the slide.  5. Device according to claim 4, characterized in that the sector (5) comprises two pins (20) arranged on either side of the sector, according to the circular path determined by the slide (4a).  6. Device according to claims 2 and 5, characterized in that the two pins (20) each comprise a head (21) for locking, disposed on the other side of the panel (4) relative to the sector (5), movable according to the height of a said stud, to come into contact with the opposite face of said panel, and thus stop said sector in rotation.  7. Device according to claim 1 or 2, characterized in that a plate (22) is mounted movable in translation on the carriage (7), perpendicular to the direction of translation (8) of said carriage, and the machining station (1) is integral with said plate.  8. Device according to claim 1 or 2, characterized in that the machining station (1) comprises a rotary tool (23), whose axis of rotation (24) is parallel to the axis of translation (8) of the carriage (7).  9. Device according to claim 2, characterized in that the orientation sector (5) comprises a guide light (5a), having the shape of a straight line parallel to the direction of translation (8) of the carriage (7) , the carriage (7) comprises a stud (26) passing through the light, and a blocking head (27) is movable according to the height of said stud, on the other side of the sector, to come into contact with the surface of the latter , and thus stop the carriage in translation.  10. Device according to claim 1 or 2, characterized in that the carriage (7) comprises a plate (28) movable in the direction of translation (8) on the sector (5), a support (29) of the tool (1) machining on one side of the sector, a support structure (30), extending on the side opposite to said sector, passing through the panel (4).  11. Device according to claim 10, characterized in that a drive means (31) in rotation of the machining tool (1) is embedded in the support structure (30).