US3483659A

US3483659A - Drill grinding machine

Info

Publication number: US3483659A
Application number: US685551A
Authority: US
Inventors: Alexander Tatar
Original assignee: Micron Etablissement
Current assignee: Micron Etablissement
Priority date: 1966-11-28
Filing date: 1967-11-24
Publication date: 1969-12-16
Anticipated expiration: 1986-12-16
Also published as: GB1200116A; CH466743A; DE1652123A1

Description

Dec. 16, 1969 'A. TATAR ,4

DRILL GRINDING MACHINE Filed NOV. 24, 1967 INVENTOR Alexander 7217A}? ATTORNEY nited States Patent O US. Cl. 51122 Claims ABSTRACT OF THE DISCLOSURE A drill grinding machine having a frame bearing a grinding wheel and a slidable drill holder, including a support stem for the work end of the drill to steady it during grinding, the support stem having a mount arranged to adjust its position of engagement with the drill and being insulated from its mount to form part of an electrical signalling circuit to show when it contacts the drill, the axis of the support stem being at 90 to the axis of the drill and the drill holder being fixed to the mount so as to follow its movements, the end of the support stern having a cutoff edge to clear the grinding wheel and an opposite groove to support the drill end, and a stop plate in the plane of the grinding wheel optionally forming part of another electrical circuit to signal the exact initial position of the drill for grinding.

BACKGROUND OF THE INVENTION Field of the invention Drill grinding machines.

Description of the prior art In drill grinding machines known until now, the drill is supported in the neighbourhood of its extremity, either by the aid of a simple support part or by means of a clamp. It is necessary, to avoid any vibration or deformation of the drill, that the support part or the clamp acts on the drill as close as possible to its end, on which the forces due to grinding are exerted.

In the case of clamps, relatively complicated and expensive solutions have been proposed.

In the case of support parts, these cannot generally be positioned in the immediate neighbourhood of the extremity of the drill, due to the fact that they then would prevent the passage of the grinding wheel. Moreover, the drill is generally applied laterally against the support part, so that is risks being broken if it is too roughly brought into contact with the latter.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome these drawbacks.

According to the invention there is provided a drill grinding machine including a frame, a grinding wheel and a drill holder to hold the drill rigidly during grinding operations, arranged on said frame so that the drill can be moved opposite the grinding wheel and brought into various positions to enable the grinding of its different faces, said machine comprising a support part for the drill to hold the drill by its end and prevent its deformation or subjection to vibration during grinding, a mount on which said support part is mounted in a movable manner so as to enable it to be brought into engagement with the drill when the latter occupies its initial grinding position, and an electrical warning device of which the supply circuit passes through the drill and through said support part in such manner that the warning device functions when the support part comes into contact with the drill, thus signalling to the operator that this contact is realized,

"ice

in order to avoid the possibility of the operator straining or even breaking the drill by untimely continuation of the approach operation of the support part.

BRIEF DESCRIPTION OF THE DRAWING In order that the invention may be more clearly understood one embodiment thereof is described below purely by way of illustrative but non-limiting example with reference to the accompanying drawing in which:

FIGURE 1 is a view in front elevation of one embodiment of a drill grinding machine according to the invention;

FIGURE 2 is a cross-sectional View along the line IIII of FIGURE 1, and on a larger scale;

FIGURE 3 is a view in elevation of a detail and on a still larger scale;

FIGURE 4 is a cross-sectional view along the line IV- IV of FIGURE 3, in which there is also shown a drill; and

FIGURE 5 is a cross-sectional view similar to FIG- URE 4, in which a drill of much smaller diameter is shown.

DESCRIPTION OF THE PREFERRED EMBODIMENT The machine comprises a frame 1, on which is mounted the motor 2 of a grinding wheel 3. Frame 1 has, on its front face, a transverse slide 4 on which a carriage 5 travels, the carriage having a support 7 fixed thereto by a bolt 6, support 7 ending in a sleeve 7a on which a second support 8 is rotatably mounted, the second support, also ending in a sleeve, designated by 8a, in which is mounted a clamp or chuck 9 bearing the drill to be ground, which is designated by 10, which is thus held rigidly during grinding.

The direction of the slide 4 is parallel to the working plane of grinding wheel 3, which working plane is designated by 11 (FIGURE 2), and with which the outer face of a stop-plate 12 borne by a part 1a of the frame 1 is coincident, and against which the drill abuts axially when it is placed in position on the machine, before grinding.

When the carriage 5 is displaced along the slide 4, the end of the drill 1t), travelling in the plane 11, effects a translation in the course of which it moves opposite the plate 12 and the grinding wheel 3.

The clamp 9 is mounted on the annular portion 8a of support 8 so as to be axially displaceable, by means of a micrometric drum 13, rigidly fixed to a threader sleeve 14, screwing into the inner tapping of a barrel 15. The latter is itself rotatably mounted on the annular part 8a which is prevented from turning by a spring rod 16, subject to the action of an opposing spring 17 engaged in one or other of a series of holes 18 on the annular face of a shoulder or flange 15a of sleeve 15. This arrangement thus permits on the one hand, adpustment of the axial position of the drill with respect to the support 8, and, on the other hand, turning of the drill around itself to an angle corresponding to the number of cutting lips of the drill, that is to say, generally, at an angle of which corresponds to the case where the drill has two cutting lips.

The rotation of support 8 around the axis of sleeve 7a of support 7, enables the tilting of the drill with respect to the plane of the grinding Wheel, with a view to the grinding of two faces, cutting and clearance, of each cutting lip.

Sleeve 7a. is traversed by a barrel 19 in which is mounted, by means of two bushes 20 and 21, of insulating material, a stem 22 serving as a support for the point of the drill. This stem is rigidly fixed axially to a micrornetric drum of which one part 23, of insulating material, is fixed to a tapped ring 24, screwing on the threaded end 19a of barrel 19, which permits adjustment of the axial 3 position of stem 22 as a function of the diameter of the drill to be ground. Stem 22 is precluded from turning on itself by a pin 25 engaged in a transverse slot 26 of an insulating head 27, fixed by screws 28 to sleeve 19.

The axis of stem 22, designated by 29 (FIGS. 3 and 4), cuts the axis, designated by 30, of the drill, at the point of the latter, and forms an angle of 90 with it.

The end of support stem 22 has a cut-off face 31, (FIGS. 3 and 4), and a conical portion 32 in which is formed a V-shaped groove 33, of which the corner constituting the bottom is situated in the plane of the axes 29 and 30. The end of drill 10 is supported by the two walls bounding groove 33. It should be noted that support stem 22 is positioned outside the axis of the drill and, thus, in no way interferes with the working of grinding wheel 3, of which the active plane 11 has been diagrammatically shown as 34 in FIGURE 4, while supporting the drill in the immediate vicinity of its point, which prevents it from vibrating or being deformed during the operations of grinding; FIGURES 4 and show that the smaller the diameter of the drill, the more support stem 22 must approach the axis of the drill.

The adjustment of the machine is efiected by placing the drill to be ground in clamp 9, then causing the latter to advance by means of micrometric drum 13 until the point of the drill abuts against stop plate 12.

The drill thus occupying axially an exact position called the initial position, support stem 22 is advanced, by operation of micrometric drum 23-24, until the wall of its V-shaped groove 33 comes into contact with the drill. This contact is easily controllable due to the fact that the machine comprises a pilot light 35, (FIG. 1), of which the supply circuit is closed when support stem 22, which is electrically insulated from the body of the machine, comes into contact with the drill. The rear end 22a, of support stem 22, is reduced in a manner to constitute a plug on which is engaged a socket of an electrical conductor forming part of the supply circuit of pilot light 35.

By means of this arrangement, the operator is immediately warned of the engagement of the support stem and the drill, thus avoiding untimely continuation of the advance of the stern, which would strain or even risk breaking the drill.

Pilot light 35 also ensures that the grinding is perfectly symmetrical. In fact, if, after having effected the grinding of two cutting lips of a drill, the latter is made to turn on itself, causing barrel 15 to turn, the pilot light must remain constantly lit, the contrary proving that the drill has an assymetry which it is advisable to correct by causing the drill to advance slightly and repeating the grinding operation until the pilot light 35 remains lit for each of the two angular positions of the drill, indicating that the grinding is perfectly symmetrical.

It is to be noted that barrel 19 is rigidly fixed angularly to the support 8, so that support stem 22 turns at the same time as support 8 when the latter is moved around the axis of sleeve 74: of support 7. As a result, the drill remains supported in groove 33 of stem 22, whatever the position of grinding.

Finally, it is to be noted that a modification of the angle of the point of the drill may be obtained by causing support 7 to turn around its fixing bolt 6, of which the vertical axis cuts that of the drill and is situated in the plane of the grinding wheel and of stop plate 12.

As a variation, stop plate 12 could be arranged in a manner to close the electrical circuit of a pilot light 36, when the drill to be ground is in contact with it, indicating thus, during the positioning of the drill on the machine, that the drill has reached axially its exact initial position of grinding.

It will be understood that various changes and modifications may be made in the embodiment described without departing from the essential concept of the invention as defined in scope by the appended claims.

I claim:

1. A drill grinding machine including a frame, a grinding wheel and a drill holder to hold the drill rigidly during grinding operations, arranged on said frame so that the drill can be moved opposite the grinding wheel and be brought into various positions to enable the grinding of its different faces, said machine further comprising a support part for the drill to hold the drill by its cutting end and prevent deformation or vibration during grinding, a mount on which said support part is mounted in a movable manner so as to enable it to be brought into engagement with the drill when the later occupies its initial grinding position, and an electrical warning device having a supply circuit passing through the drill and through said support part in such manner that the warning device functions when the support part comes into contact with the drill, thus signalling to the operator that this contact is realized, in order to avoid straining or breaking the drill by untimely continuation of the approach operation or' the support part.

2. A machine according to claim 1, wherein said sup port part comprises a stem arranged so that its axis cuts that of the drill, said stem being mounted on its mount in an axially movable manner and having an end which co-operates with the end of the drill.

3. A machine according to claim 1, wherein the axis of said support part forms an angle of with the axis of the drill.

4. A machine according to claim 1, wherein said support part comprises a stem, of which the support end has an inclined surface with respect to the axis of the stem, said support end having a V-shaped groove whose bottom is situated in the plane passing through the axes of the stem and the drill, and by which groove the point of the drill can be supported.

5. A machine according to claim 1, wherein said support part is fixed to the holder in a manner whereby said support part follows the movements of the drill.

6. A machine according to claim 1, comprising an axial stop for the drill, against which the drill can be supported when it occupies its initial position, prior to grinding, and an electrical signalling device which comes into operation at the instant when the drill comes into contact with said axial stop, to signal the operator that the initial axial position of the drill has been achieved.

7. A machine according to claim 6, comprising a contact device situated in the working plane of said axial stop to actuate the drill and close the supply circuit of said electrical signalling device.

8. A machine according to claim 1, wherein said eletrical warning device comprises a pilot light which is lit when the drill and its support part are in contact with one another.

9. A machine according to claim 1, wherein the drill holder enables the drill to be rotated about its longitudinal axis for grinding its different lips, the electrical warning device enabling control of the symmetry of grinding by said rotation of the drill, in the course of which, if the grinding has a fault of symmetry, the contact between the support part and the drill is interrupted, which is shown by corresponding interruptions in the illumination of the pilot light.

10. A machine according to claim 5, wherein said mount and said drill holder are fixed to the frame by means of a part having a vertical axis which cuts the axis of the drill and is situated in the plane of the grinding wheel.

References Cited UNITED STATES PATENTS