EP0040137B1 - Finishing machine for hard materials, especially quartz - Google Patents

Description

The present invention relates to a grinding or grinding machine, of hard materials, and in particular of quartz with piezoelectric effect, by abrasion, of the type in which the part is worn by friction against a surface on which an abrasive is deposited.

By the patent of the United States of America US-A-2, 469.563, a machine of this type is known, making it possible to carry out simultaneous grinding of two faces of the parts to be grinded. These parts, which are in the form of plates, are each arranged in one of a plurality of cylindrical cells, formed in a fixed annular retaining element, and regularly distributed around the axis of symmetry of the annular retaining element, the underside of each insert resting on an upper friction surface of a cylindrical rectification element also received in the corresponding socket, and an upper rectification plate resting on the upper face of the inserts projecting out alveoli. The upper grinding plate is driven by a main oscillatory or rotary movement, being mounted by its central part on an eccentric spindle, driven in rotation around the axis of symmetry of the annular retaining element, as well as an intermittent or continuous secondary movement, ensured, respectively, by means of an elastic return roller or roller cooperating with a toothing formed on the periphery of the upper grinding plate, each time the latter is brought against the roller in its movement main, or by means of a toothed wheel secured to the eccentric pin and engaged with a fixed pinion coaxial with the axis of symmetry of the annular retaining element, an arm, the free end of which carries a finger penetrating into a blind hole on the upper face of the upper plate, being further articulated by its other upper end of the spindle, so that there occurs a renewal, respectively, intermittent or conti bare, from the lower surface of the upper grinding plate in contact with the upper face of the wafers, the grinding of which is facilitated by the supply, towards the latter, of an abrasive flowing through conduits, according to a well-known characteristic .

The use of this machine, of the so-called "eccentric" type, does not allow the relative movements described by the surfaces in contact to be adapted as well as the speeds with which these movements are described, in order to obtain good accuracy, regardless of the nature of the hard material to be ground. Incidentally, this machine does not make it possible to choose the planes according to which each face of a wafer must be rectified.

German patent DE-B-1,029,699 describes a flat stone polishing machine in which the stone is supported by a turntable resting on hydraulic cylinders connected to a common chamber by means of restrictions. Thus the pressure, which the grinding wheel exerts on the thickest parts of the stone, causes a modification of the position of the latter relative to the grinding wheel by hydraulic compensation of the pressures in the support jacks. The stone then quickly finds an average position corresponding substantially to the theoretical plane of "smoothing the bumps and hollows. This arrangement does not have the guiding qualities necessary for polishing crystals such as quartz and furthermore does not make it possible to choose and maintain the orientation of the face to be polished with respect to a determined direction.

Indeed, we know that crystallized materials, and in particular quartz, have axes of crystallization and that the radioelectric characteristics of quartz wafers depend in a very sensitive way on the angle formed by their faces with their axes of crystallization. . In practice, after rectification in a prowler, for example of the type described above, the quartz having the desired angles is selected by goniometry and a large part of them is rejected. Of course, this statistical selection leads to a high cost price of the quartz plates usable for example in radio transmissions for controlling the oscillator stages.

A first object of the present invention is a grinding machine making it possible to rectify parts made of hard materials, such as quartz, and to make them flat and parallel by turning once the correction is made on one face.

A second object of the present invention is to allow, in a grinding machine, the adjustment of the angle of the faces relative to the main axis of the crystal to the desired value, as well as that of the thickness of the pieces while obtaining a very good surface condition.

To this end, the machine, according to the invention, for the grinding of parts made of hard materials by abrasion, comprising ducts for supplying an abrasive to the parts arranged in the cells of a fixed plate, above which a friction surface is driven in rotation, as is the case in the machine which is the subject of the aforementioned patent, is characterized in that it comprises a planetary system, rotating above the fixed plate, and the satellites of which rotate above the parts, so that the underside of the satellites constitutes the friction surface capable of being brought into contact with the upper faces of the parts, each placed on a table also placed in the corresponding plate of the fixed plate.

Thus, unlike the arrangement used in the prior art, the satellites rotate in cycloidal movements beyond above plates or parts carried by tables and remaining fixed on the tray.

According to another characteristic of the invention, the tables are pivotally mounted on the edge of a knife placed below one of their ends, the angular position of each table being adjusted by the action of a micrometric screw carrying under the table in the vicinity of another end, each position adjustment being carried out individually, so that it is possible to erode the plates at a determined angle.

Advantageously in this case, each table is mechanically biased against a base, arranged in the fixed plate, and carrying on the one hand, the knife, and on the other hand, the drive means of the micrometric screw, such as a stepper or direct current motor, by a magnetic suction cup, whose body is fixed to the base and whose pole plate is fixed to the table.

It is thus possible to obtain a very fine adjustment of the inclination of the table relative to the plate, and consequently, of the precise angles of the faces of the plates mounted on each table.

According to another characteristic of the invention, the quartz plates are held on the aforementioned tables by suction. This is obtained by using tables having a multitude of orifices opening at their upper faces and joined together by means of a collector to a suction device.

Indeed, at the level of precision at which the machine works, the fixing of the quartz plates on the tables by a drop of adhesive of a few microns would cause angular differences detrimental to the quality of the result that one wishes to obtain.

The cooperation of satellites and plates for running-in can be ensured by mounting the base on the rods of a jack and by guiding it by vertical rails on guide columns, the jack controlling the elevation of the base and tables at as the parts are abraded.

In a first embodiment, the satellites are driven by an internal toothed ring and guided by an external toothed ring secured to a fixed plate support, the internal toothed ring being itself driven by an axis extending to the inside a sheath through the base, the axis itself being driven by a motor.

In a second embodiment, the satellites are rotated with a planet carrier plate, under which each satellite is suspended by means of a gimbal type transmission, the planet carrier plate being mounted in rotation under an arm a bracket whose mast is disposed laterally relative to the fixed plate. Preferably, in this case, the satellites are each driven in rotation on themselves on an axis passing through the planet carrier plate and secured, above the latter, to a pulley connected by a belt to a central pulley, coaxial with the planet carrier plate, and capable of being driven in rotation independently of the rotation of the planet carrier plate, so that the speed and the direction of rotation of the satellites on themselves can be chosen independently of the speed and direction of rotation of the planet carrier plate, which allows a very advantageous adaptation of the machine to the nature of the hard material constituting the plates to be lapped. The means for driving in rotation the planet carrier plate as well, possibly those which ensure the proper driving of the pulley, are carried by the bracket, preferably by the arm mounted to pivot on the mast, and sliding along this latest.

• la figure 1 une coupe verticale d'un premier exemple de rectifieuse selon la ligne I-I de la figure 2 ;
• la figure 2 une vue en plan de la machine selon la figure 1 ;
• la figure 3 une vue en coupe représentant le montage d'une table ;
• la figure 4 une coupe verticale de la même table selon un plan radial différent ;
• la figure 5 une table en position inclinée ;
• les figures 6, 7 et 8 des schémas d'explication du processus opératoire, sur lesquels les dimensions sont considérablement exagérées pour faciliter la compréhension ;
• la figure 9 une vue latérale d'un second exemple de rectifieuse et
• la figure 10 une vue en plan de la machine selon la figure 9.

Other characteristics and advantages of the invention will become apparent during the description which follows the particular embodiments, given solely by way of nonlimiting examples, with reference to the figures which represent:

• Figure 1 a vertical section of a first example of a grinding machine along line II of Figure 2;
• Figure 2 a plan view of the machine according to Figure 1;
• Figure 3 a sectional view showing the mounting of a table;
• Figure 4 a vertical section of the same table in a different radial plane;
• Figure 5 a table in an inclined position;
• Figures 6, 7 and 8 diagrams of explanation of the operating process, on which the dimensions are considerably exaggerated to facilitate understanding;
• FIG. 9 a side view of a second example of a grinding machine and
• FIG. 10 is a plan view of the machine according to FIG. 9.

In Figure 1, we see that the machine consists of a base 1 on which is mounted a base 2, both preferably of granite, the base 2 can move vertically along five guide columns 3 under faction d 'a jack 4, preferably comprising three rods 5. The base 2 is pierced, in its central part, with a bore 6 through which passes a sheath 7 containing a drive axis 8, which drives the internal toothed crown 9 in rotation. Satellites 10 are supported by their teeth on the one hand on the pinion 9 and on the other hand on the external toothed ring 11. The shaft 8 is rotated by a bevel gear 12, the shaft of which 13 is connected to an electric motor, not shown.

Above the satellites 10 comes to bear a cover 14, the interior of which has conduits 15 whose role is to ensure the routing of the abrasive intended for lapping the quartz plates which are very schematically represented in 16. The quartz plates are placed on tables 17, the mounting of which inside the cells of the fixed plate 18 will be explained later. The plate 18 and the outer ring 11 rest on a fixed support 19.

We see in Figure 2, the outer ring gear 11 inside which are supported three satellites 10 shown in broken lines and driven by the inner ring gear or pinion 9. In the example shown, the plate 18 carries five tables 17. The base 2 slides on the columns 3 by means of vertical guide rails 20 on which come rolling tables. Preferably, the base 1 and the base 2 are made of granite, the stability of which compares advantageously with that of cast iron. The precision rolling tables make it possible to obtain an absolutely vertical displacement, which is necessary so that the plate 18 is very exactly horizontal. It is in fact with respect to the position of the plate 18 that we will determine the inclination of the tables 17 and consequently the inclination of the faces of each quartz with respect to its main axis.

The operation of the machine is generally as follows: the base 2 occupying its low position by retraction of the rods 5 of the jack 4 inside the cylinder body, the quartz plates are placed on the tables 17 and held thereon as explained later. The satellites 10 are arranged above the quartz plates and the cover 14 is lowered. Then, by the action of the jack 4, the base 2 is pushed upwards. The pinion 9 is rotated while the abrasive arrives through the conduits 15.

After a suitable time, the circle 2 descends, the cover rises and the machined inserts are removed and turned over, then, after their double machining, replaced by new inserts.

FIG. 3 represents a vertical section through a radial plane passing through the axis of the machine representing in partial view the mounting of a table 17 on the base 2.

According to a characteristic of the invention, the machine makes it possible to obtain an inclination of the tables 17, on which the quartz plates (not shown in FIG. 3) are arranged, so as to obtain the formation of an angle between a face of said plate and the horizontal plane. As explained above, a table 17 is included in a cell 21, formed in the plate 18 mounted on the support 19, by means of a seal 22 which prevents the abrasive from entering the inside of the mechanism of the machine.

The table 17 is supported by the base 2 preferably by means of a magnetic suction cup, the body 23 of which is screwed by a screw 24 into the base 2, and the pole plate 25 of which is integral with the table 17 by a screw 26. The table 17 rests by its two ends on the one hand on a pivot 27, knife-shaped, secured to the base 2 by one of its ends, and on a micrometric screw 28, whose movement is controlled by a stepping or direct current motor 29.

Under these conditions, it is easily understood that, by action on the electric motor 29, it is possible to give a very slight inclination to the table, therefore to the upper surface of the plates, if they are initially with faces parallel to the horizontal,

There is shown in Figure 5 a table 17 in the inclined position.

FIG. 4 represents a section similar to that of FIG. 3, but by another radial plane, which makes it possible to distinguish the system for holding the wafers in a horizontal position by a set of conduits 30 interconnected by a manifold 31 with a pipe 32 connected to any device capable of producing a strong depression. The three quartz plates 16 are held against the forces applied to them laterally by a frame 33. As previously indicated, the device for holding and applying the plates against the table surface makes it possible to avoid errors. angle resulting from the presence of drops of adhesive of undetermined diameter.

Figures 6, 7 and 8 are diagrams for understanding the process of developing quartz wafers with parallel faces oriented relative to the main axis.

In Figure 6, we see a plate 16 and its main axis extending in the direction 16a.

The first step is to make the upper face 16b parallel to the axis 16a. This is obtained as explained above by tilting the table 17 by a determined angle. Then, the wafer is turned over and, according to the same inclination, the face 16c is lapped so as to become parallel to the face 16b, and consequently to the main axis 16a. Under these conditions, a quartz or a quartz plate is obtained, the faces 16b and 16c of which are parallel to each other on the one hand and parallel to the direction of the main axis on the other or inclined thereon. a well-defined angle.

Obviously, the position of the faces 16b and 16c relative to the main axis is determined by direction finding by rectification. The machine according to the invention therefore makes it possible to produce parts the opposite surfaces of which form an angle of a certain precision while having perfect flatness, which makes it possible to use quartz which previously was rejected as having insufficient radioelectric characteristics.

Furthermore, only a very low pressure is applied to the cylinder 4, which can be a hydraulic or pneumatic cylinder, just intended to compensate for the elimination of the material due to abrasion, a system for evacuating the abrasive and powdered material being provided.

Of course, although in FIG. 4 only three platelets have been shown, the number of quartz platelets carried by a table can be much greater. All the plates carried by a table will undergo the same angular retification and of course must be selected before assembly.

The machine shown in Figures 9 and 10 differs from that shown in Figures 1 to 5 only in the constitution and drive of the planetary system, which, in this second embodiment, does not include any of the elements following; pinion 9, drive shaft 8, sheath 7, angular gear 12 and shaft 13, and external gear ring 11. On the other hand, there are three satellites 10 suspended under a planet carrier plate 34, to which they are each connected by a universal joint 35 at the lower end of an axis 36, passing through the planet carrier plate 34, and the upper end of which, projecting above the latter, is rotatably secured to a pulley 37, connected to similar pulleys 37 of the other satellites 10 ′ by a belt 38 also engaged in the groove of a central pulley 39. This central pulley 39 is fixedly mounted on the lower end of a sleeve crossed coaxially by a shaft 40, mounted journalled in the free end of the arm 41 of a bracket whose other end is pivotally mounted around the mast 42 of the bracket disposed vertically on the base 1, on the side of the fixed plate 18 and its support 19. The planet carrier plate 34 is integral in rotation, by its part c entry, from the lower end of the shaft 40, the upper end of which, projecting above the arm 41 of the bracket, is rotationally secured to a pulley 43 connected by a belt 44 to a pulley 45 fixed on the output shaft of an electric drive motor 46 carried by the pivoting end of the arm 41, in a direction diametrically opposite to that directed towards the shaft 40 relative to the pivot axis of the arm 41 on the mast 42 of the gallows, for the purpose of balance.

It is thus possible to ensure the rotation of the planet carrier plate 34 on itself, the satellites 10 also being driven in rotation about the vertical axis of the shaft 40, due to their connection to the planet carrier plate 34. But, simultaneously, due to their connection by the belt 38 connecting the pulleys 37 to one another and to the central pulley 39, the satellites 10 are driven in rotation on themselves according to a speed and a direction of rotation defined at from the speed and the direction of rotation of the planet carrier plate 34 on itself.

It is also possible, by means of an auxiliary motor, also carried by the arm 41 of the bracket, or from a power take-off suitably chosen on the motor 46 or the pulleys 45 and 43, and by means adapted references, to drive the central pulley 39 in rotation independently of the rotational movement of the planet carrier plate 34, so that the direction and the speed of rotation of the satellites 10 on themselves are chosen independently of the direction and the speed of rotation of the planet carrier plate 34, which makes it possible to adapt to the hard material from which the plates to be lapped are made.

Finally, suitably placed stops limit the pivoting of the arm 41 of the bracket between a working position, perpendicular to the fixed plate 18, and a rest position, in which the planetary system is released laterally relative to the plate. fixed 18.

In addition, the arm 41 of the bracket is slidably mounted along the mast 42 and its vertical movements are controlled by a hydraulic or pneumatic cylinder (not shown) housed in the mast 42, making it possible to apply the satellites 10 to the fixed plate 18, or to release them from this plate 18, which controls the flatness of the satellites 10 suspended by cardan joints 35 under the planet carrier plate 34.

In this embodiment, the abrasive supply conduits (not shown) can be arranged in a substantially radial position so that the abrasive is supplied either between the satellites 10 and the planet carrier plate 34, if these conduits are carried by the bracket and moved with the planetary system, or between the satellites 10 and the fixed plate 18 if these conduits are carried by the base 1 for example.

The machines which have just been described are also perfectly suited to the very precise size of all other hard materials other than quartz.

It goes without saying that modifications can be made to the embodiments which have just been described, in particular by substitution of equivalent technical means, without departing from the scope of the present invention as claimed in the claims.

Claims (14)

1. Machine for truing articles (16), made of hard materials, by abrasion, comprising feed channels (15) for feeding an abrasive to the articles (16), arranged in the pockets (21) of a fixed plate (18) above which a friction surface is rotationally driven, characterised in that it comprises a planetary system rotating above the fixed plate (18), the satellites (10) of which system rotate above the articles (16) so that the lower face of the satellites (10) constitutes a friction surface which can be brought into contact with the upper faces of the articles (16) placed on tables (17) also arranged in the pockets (21) of the fixed plates (18).

2. Truing machine according to Claim 1, characterised in that the abovementioned tables (17) are mounted pivotingly about a knife (27) located below one of their ends, the angular position of each table (17) being adjusted by the action of a micrometer screw (28) acting on the said table (17) near the second end and the said position adjustment being individual.

3. Machine according to one of Claims 1 or 2, characterised in that each table (17) is mechanically urged against a plinth (2) located below the plate (18) and carrying firstly the knife (27) and secondly the means (29) of driving the micrometer screw (28), the said urging being effected by a magnetic sucker of which the body (23) is firmly fixed to the plinth (2), and of which the pole plate (25) is firmly fixed to the table (17).

4. Machine according to Claim 3, characterised in that the means of driving the micrometer screw (28) consist of a stepping motor or direct current motor (29).

5. Machine according to any one of Claims 1 to 4, characterised in that the abovementioned tables (17) are perforated by a plurality of orifices (30) opening at the upper faces of the tables and joined by means of a manifold (31) to a suction device (32).

6. Machine according to any one of the preceding Claims 3 to 5, characterised in that the abovementioned plinth (2) is mounted on the rods (5) of the jack (4) and is guided by vertical guide rails (20) on guide columns (3), the said jack (4) causing the plinth (2) and the tables (17) to be raised at the rate at which the articles (16) are abraded.

7. Machine according to any one of Claims 1 to 6, characterised in that the abovementioned satellites (10) are driven by an inner toothed rim (9) and guided by an outer toothed rim (11) firmly fixed to a support (19) of the fixed plate (18).

8. Machine according to Claim 7, characterised in that the abovementioned inner toothed rim (9) is itself driven by a shaft (8) which passes within a sleeve (7) through the plinth (2) and is itself driven by an electric motor.

9. Machine according to one of Claims 1 to 8, characterised in that the planetary system is covered by a cover (14) perforated with abrasive feed channels (15).

10. Machine according to any one of Claims 1 to 6, characterised in that the abovementioned satellites (10) are rotationally driven with a satellite-carrier plate (34) below which each satellite (10) is suspended by means of a cardan-type transmission (35), the satellite-carrier plate (34) being rotationally mounted under an arm (41) of a T-piece of which the vertical member (42) is arranged to the side of the fixed plate (18).

11. Machine according to Claim 10, characterised in that the satellites (10) are each driven to rotate about themselves on a shaft (36) passing through the satellite-carrier plate (34) and firmly fixed, above the said plate, to a pulley (37) connected by a belt (38) to a central pulley (39) coaxial with the satellite-carrier plate (34) and capable of being driven rotationally independently of the rotation of the satellite-carrier plate (34).

12. Machine according to one of Claims 10 and 11, characterised in that the rotational drive of the satellite-carrier plate (34) and, if appropriate, the rotational drive of the central pulley (39) is provided by drive means (43, 44, 45, 46) carried on the T-piece.

13. Machine according to any one of Claims 10 to 12, characterised in that the arm (41) of the T-piece is mounted so as to pivot and slide on the vertical member (42).

14. Machine according to any one of Claims 1 to 13, characterised in that it is mounted on a granite base (1), the abovementioned plinth (2) also being made of granite.

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