LU83914A1 - MACHINE TOOL TO AUTOMATICALLY RECIVER, BRIGHTEN OR RIBLATE GRINDERS FOLLOWING A PREDETERMINED PROFILE - Google Patents

Description

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The subject of the present invention is a process for automatically rectifying, sharpening or re-grinding a first circular grinding wheel which is driven in rotation about its axis, using it by friction using a second circular grinding wheel which the it also drives in rotation about its axis, while moving longitudinally and / or transversely the two abovementioned grinding wheels relative to one another by applying them one against the other.

The invention is particularly applicable to dressing, resharpening or raking diamond grinding wheels. It also relates to a machine tool designed to implement the method according to the invention.

Oh knows a process to cut, straighten or sharpen a grinding wheel thanks to the pressure exerted on it by a very hard steel wheel and precisely profiled on demand.

There are also known grinding machines with a rotating head, the grinding wheel head of which is supported by a transverse slide of a carriage animated by a reciprocating movement and by a crossed transverse movement to which a transverse movement of taken.

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This known machine tool is made up of a rigid frame carrying a first grinding wheel carried by a spindle mounted on a grinding wheel carriage with crossed movement, the clearance-free guidance of which ensures great precision in shape and size of the grinding wheel to be sharpened. The longitudinal movements of the grinding wheel carriage are obtained by an oleo-hydraulic control so as to guarantee. constant pressure of the second wheel on the first.

The mechanism for controlling the movement of the grinding wheel carriage is designed for manual advance and automatic advance each time the longitudinal movement of the carriage is reversed or each time the table movement is reversed, in order to allow a regulated micrometric advance so as to compensate for the wear of the grinding wheel at each end of travel, in order to obtain high precision.

As these machines are generally intended for serial work, the diameter of the part or the movement of the carriage is directly controlled by pneumatic or electronic devices.

The second grinding wheel or grinding wheel moves while maintaining its axis of revolution, parallel to that of the first grinding wheel or grinding wheel, the micrometric setting advance, by which the second grinding wheel advances transversely towards the first grinding wheel in sight to compensate for the wear of the second wheel, being done at each end of travel.

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In these known machine tools, the grinding wheel and the sharpening wheel rotate in the same direction around their respective axes of revolution which are substantially parallel to each other, so that at their point of contact, the two wheels have tangential speeds directed in opposite directions.

The tangential speed of rotation of the first grinding wheel (grinding wheel) is generally 1.5 at m / sec .; the tangential speed of rotation of the second wheel (sharpening wheel) is generally between 20 and 25 m / sec. in a direction opposite to the first. The translation speed per revolution of the first wheel can be between 3/4 and 1/2 of the width of the second wheel per revolution of the first wheel.

Dressing takes place dry.

It is a fairly delicate operation which must be carried out with great care and precision if we want to avoid certain disadvantages such as veneers, reproduction or resumption of grinding wheel.

Experience has shown that you should never wait until the wheel is very worn before resharpening it.

However, the known methods of dressing or raking a grinding wheel are quite long and require very specialized labor. When dressing or raking a diamond grinding wheel, using a silicon carbide grinding wheel, it must be taken into account - 5 - that the silicon carbide grinding wheel wears out much faster than the diamond grinding wheel that must be resharpened.

The present invention aims to remedy the drawbacks of known methods and relates to a process for erecting, rectifying, sharpening or refining a first circular grinding wheel which is driven in rotation about its axis, by using it by friction with the using a second grinding wheel, which is also driven in rotation about its axis, while moving the two grinding wheels longitudinally and / or transversely with respect to one another by applying one to the center other, this process being essentially characterized in that the two abovementioned wheels are rotated about their respective axis in opposite directions of rotation so that the tangential speeds, at the common point of contact of the two wheels are directed in the same direction but are of different sizes.

According to a feature of the invention, the axes of rotation of the first and the second grinding wheel are kept substantially parallel. The axis of rotation of the first wheel is advantageously fixed.

The subject of the invention is also a machine tool for straightening, grinding, sharpening or grinding a first circular grinding wheel rotating around its axis, using a second circular grinding wheel, rotating - 6 - also around its axis, designed to implement the method, thanks to the longitudinal and transverse displacements of a grinding wheel relative to the other, the two grinding wheels being pressed against each other, this machine tool being essentially characterized in that the directions of rotation of the aforementioned two grinding wheels around their respective axes are opposite so that the tangential speeds, at the common point of contact of the two grinding wheels, are directed in the same direction, but are of different sizes.

In a particular embodiment of the machine tool according to the invention, the first and second grinding wheels rotate around axes of rotation remaining substantially parallel to each other. The axis of rotation of the first wheel is preferably fixed.

The two grinding wheels are advantageously each mounted on a high precision grinding wheel spindle.

If the first wheel has to be erected or strapped to a well-defined profile, it is necessary to use a machine, the second wheel of which is carried by a cross-wheeled carriage. The crossed carriage moves longitudinally and transversely along a predetermined path generated by a roller supported on a template corresponding to the desired profile.

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In a more sophisticated machine, the transverse displacements of the grinding wheel carriage include a transverse micrometric advance of setting so as to compensate at each end of stroke and automatically the wear of the grinding wheel.

Other particularities and details of the invention will emerge from the appended figures.

In these different figures: - Figure 1 is a perspective view of the machine tool according to the invention; - Figure 2 is a perspective view of the first grinding wheel and the sharpening wheel; - Figure 3 is an end view of the grinding wheels shown in Figure 2; - Figure 4 is a perspective view of the template and the guide roller which controls the grinding wheel carriage with crossed movement; - Figures 5 and 6 show in detail the porous structure of the dLamantée concretion of a grindstone re-sharpened by a process known respectively by the process according to the invention.

The same reference notations designate in the i above figures identical or similar elements.

Figure 1 shows in perspective a machine tool designated as a whole by the reference notation 1 designed both as a waist and as a machine tool for profiling grinding wheels, in particular diamond grinding wheels according to a determined profile. . It essentially consists of a very rigid frame 1 mounted on a stand 2 and provided with a motor not shown and with a four-stage pulley transmission system hidden from the rear 3 with a view to driving through an intermediate bearing with variable pulleys (movable plates) a spindle 5 of high precision which carries in cantilever a first grinding wheel to be sharpened. The variable speed of rotation is between 180 to 6000 rpm.

The frame 1 comprises a cross-movement table 7 on which is mounted a carriage 8 driven by a lateral movement back and forth and by a transverse transverse movement. The movements of the carriage 8 are controlled by an oleo-hydraulic control 9 of the carriage, which comprises a copier roller 10 applied elastically with the aid of a spring not shown against a template 11 of determined shape.

On the transverse movement of the carriage determined by the template 11, there is superimposed a micro-metric advance of automatic setting, carried out after each inversion of the movement of the table called square cycle, knows effected centime during the movement of the table, or resulting from a combination of the two types of movement, in order to determine a micrometric advance adjusted so as to best compensate - b - - 1 * wear of the grinding wheel during 1 * sharpening operation, in order to obtain high precision.

A crank 12 makes it possible to move the motor relative to the drive pulley with movable plates to vary the speed of rotation of the spindle 5 supporting the grinding wheel 6, in order to choose an optimum value for it, namely 25 m / sec.

The sharpening wheel 13 is carried by the grinding wheel carriage 8 with crossed movement using a pin 14 of high precision consisting of a bearing 15 and a counter bearing 16 which enclose the wheel 13, held in place using flanges 17.

The spindle 14 carrying the sharpening wheel 13 is driven by a direct current electric motor of adjustable speed and a transmission system enclosed in a casing 18. The diameter of the sharpening wheel 13 is checked and its speed of rotation is adjusted to the using a potentiometer not shown, so that the peripheral speed of the grinding wheel 13 is kept close to 28 m / sec.

As shown in FIGS. 2 and 3, the grinding wheel 13 moves while keeping its axis of revolution parallel to that of the first wheel 6.

The two grindstones 6, 13 above rotate around their axis in opposite directions of rotation, indicated by the arrows X and Y, so that the tangential speeds, at the common point of contact of the two grindstones - '0 - ": "BP *> are pointing in the same direction, but are of slightly different sizes.

Thus, the tangential speed of rotation of the first grinding wheel (grinding wheel) is generally 25 to 28 m / sec .; the tangential speed of rotation of the second wheel (sharpening wheel) is generally between 20 and 25 m / sec. in a direction opposite to the first. The speed of translation per revolution of the first wheel can be between 3/4 and 1/2 of the width of the second wheel per revolution of the first wheel, so as to ensure the sliding and rolling of the sharpening wheel 13 by relative to the grinding wheel 6, about 3 m / sec. The sharpening wheel 13 is surrounded by a protective cover 19.

An adjustment button 20 makes it possible to manually position the grinding wheel 13 and the template 11 with respect to the reforming plane or with respect to the grinding wheel 6.

Finally, the machine comprises a control panel 21 comprising the start and stop switches for each of the grinding wheels, of the oil-hydraulic group, a working time timer 22 and a speed and load indicator 23.

If the machine tool is intended to be used as a glass cutting lathe, two armrests 24 are provided, the height of which can be adjusted using jacquard nuts 25 · A foot control 26 enables a single stroke of sweep of carriage 8, in order to carry out one training & mile at a time (step by step).

As mentioned above, the above machine allows two operations to be carried out together or separately, namely the cutting of glasses using a diamond or ceramic grinding wheel and the sharpening of a cutting wheel (diamond or ceramic).

A first circular grinding wheel 6 is rotated, driven in rotation about its axis, by using it by friction using a second circular grinding wheel 13 also driven in rotation around its axis.

The grindstones 6, 13 are formed by grains of abrasives connected to each other by a bonding agent. The characteristics of the grinding stones vary according to the combinations of grains and the bonding agent - the material constituting the abrasive - the composition of the bonding agent - the size of the abrasive particles - the structure or spacing of the grains which reflects the proportion of 'abrasive and caking agent.

The method of dressing the grinding wheels according to the invention gives the grinding wheel to be sharpened an open porous structure shown in FIG. 6, while the methods known to date give a structure represented by a closed structure clearly scratched by the loosening of the abrasive grains , shown in Figure 5 ·. An open porous structure, with spaced abrasive grains, is suitable for high flow work because the removed material finds place between the grains, which better cools the abrasive grains (diamond) and allows a less rapid wear of the grinding wheel and a better bite.

On the other hand, a grinding wheel with too closed a structure gets dirty quickly.

By the process according to the invention, the sharpening wheel imprints the abrasive grains in the diamond concretion of the grinding wheel while practically not tearing them off.

The machine tool according to the invention makes it possible to sharpen the grinding wheel 6, at regular and programmed intervals or step by step by pedal, if the latter is used for cutting a glass.

According to a feature of the invention, the dressing of the grinding wheels can be carried out dry or under watering. Watering has several advantages because it cools the room and removes abrasive particles.

As shown in FIG. 4, the position of the sharpening wheel 13 and the template 11 can be adjusted with respect to the reference plane using the vernier 27.

The system makes it possible to replace or change the template and to reposition the roller by removing the clamp 28.

It is also possible to modify the course of the lateral sweeping movement of the carriage 8 by moving the electrical contact stops, which are connected or removed, connected to the connections 29.

It is obvious that the invention is not limited to the details described above for re-sharpening a grinding wheel and that numerous modifications - 13 - can be made to these details - without departing from the scope of the invention .

Thus, the machine tool according to the invention can be used both as a waist and as a sharpening machine for resharpening, for example, the grinding wheel which is used for cutting a glass, each time the cutting is interrupted.

This machine tool can also be used to sharpen the grinding wheels of other lathes or automatic glass cutting machines.

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Claims (11)

1. Method for dressing, grinding, sharpening or grinding a first circular grinding wheel which is driven in rotation about its axis, using it by friction using a second grinding wheel, which is also driven in rotation about its axis, while moving the two grinding wheels longitudinally and / or transversely with respect to each other and applying them against each other, characterized in that the two abovementioned grinding wheels are rotated around their respective axis in opposite directions of rotation, <fe manike that the tangential speeds, at the common point of contact of the two grinding wheels, directed in the same direction, be of different sizes. 2. Method according to claim 1, characterized in that the axes of rotation of the first and the second grinding wheel are kept substantially parallel. 3. Method according to claim 1 or 2, characterized in that the axis of rotation of the first wheel is fixed. 4. Machine tool for straightening, grinding, sharpening or grinding, a first circular grinding wheel rotating around its axis, using a second circular grinding wheel also rotating around its axis, designed to carry out the process according to the 'any one of the preceding claims, by virtue of the longitudinal and transverse movements of one grinding wheel relative to the other' - 15 - the two grinding wheels being pressed against each other, characterized in that the directions of rotation of the two The abovementioned wheels around their respective axis are opposite so that the tangential speeds, at the common point of contact of the two wheels are directed in the same direction, but are of different sizes. 5. Machine tool according to claim 4, characterized in that the two grinding wheels rotate about axes of rotation remaining substantially parallel to each other. 6. Machine tool according to claim 4 or 5, characterized in that the first wheel is fixed. 7. Machine tool according to any one of the preceding claims, characterized in that the two grinding wheels are each mounted on a high precision grinding spindle. 8. Machine tool according to any one of the preceding claims, characterized in that the second grinding wheel is carried by a grinding wheel carriage with crossed movement. 9. Machine tool according to claim 8, characterized in that the longitudinal and transverse displacements of the aforementioned crossed carriage are obtained by oleo-hydraulic, pneumatic or electronic control. 10. · Machine tool according to claim 8 or 9, characterized in that the crossed carriage moves' - 16 -. longitudinally and transversely along a predetermined trajectory generated by a roller applied against a template having a shape which corresponds to the desired profile. 11. Machine tool according to any one of the preceding claims, characterized in that the transverse displacements of the grinding wheel carriage include a transverse micrometric advance of grip so as to compensate at each end of travel and automatically the wear of the grinding wheel . / V