Drilling Head With Jointly or Individually Radially Adjustable Tools

The present invention relates to the field of machining by drilling using conventional or numerically controlled machines, in machine shops or by means of equipment in general purpose establishments, and has for its object a drilling head.

Rough-shaping heads having plate holders that are separately adjustable in diameter and one of which plate holders is separately adjustable in height, are known from France No.-A-2 563,132 and from the corresponding certificate of addition application No. 84 14 315.

These drilling heads have certain advantageous features, but are encumbered with the necessity of adjusting on a preadjustment bench, or by means of special adjusting devices.

The present invention has as as object to overcome these disadvantages.

Specifically, it has as an object a drilling head characterized in that it is essentially constituted by a body for fastening in a mounting support, a casing for receiving elements in motion mounted with the possibility of axial displacement in the body, a device for radial adjustment of the tools, and a means for actuating the adjustment device, the adjustment device and the means for actuating being maintained in the casing.

The invention will be better understood thanks to the following description, which relates to a preferred embodiment, given by way of non-limiting example, and explained with reference to the accompanying schematic drawings, in which:

FIG. 1 is a view in elevation and partially in section of a drilling head according to the invention;

FIG. 2 is a sectional view along the line A--A of FIG. 1;

FIG. 3 is a sectional view along line B--B of FIG. 2;

FIG. 4 is a sectional view along line C--C of FIG. 2;

FIG. 5 is a plan view, on an enlarged scale, of the casing 2;

FIG. 6 is a sectional view along line D--D of FIG. 5;

FIG. 7 is a side elevational view, partially in section, of the radial adjustment device;

FIG. 8 is a plan view according to FIG. 7;

FIG. 9 is a view in elevation and partially in section of a variation of the head according to FIG. 1;

FIG. 10 is a sectional view along line A--A of FIG. 9;

FIG. 11 is a sectional view along line B--B of FIG. 9, and

FIG. 12 is a half-view in section along the line C--C of FIG. 9.

According to the invention, and as is shown more particularity by way of example in FIGS. 1 to 4 of the accompanying drawings, the drilling head is essentially constituted by a body 1 for fastening in a mounting support and in which is mounted, with the possibility of axial displacement, a casing 2 for reception of the movable elements, a device 3 for radial adjustment of the tools, and a means 4 for actuating the device 3, this latter and the means 4 being maintained in the casing 2.

The casing 2 (FIGS. 5 and 6) is in the form of a cylindrical element mounted in a receiving bore of the body 1, such that it is adjustable in position, and provided, on the one hand, with a bore 5 opening on the face of the casing 2 directed toward the base of the bore of the body 1, and a bore 6 of greater diameter communicating with the bore 5 and concentric with this latter, and opening on the other face of the casing 2, and, on the other hand, with a circular arc-shaped groove 7 extending partially around the bore 5 in the base of the bore 6, and a closed longitudinal groove 8 extending parallel to its longitudinal axis on an exterior generatrix and cooperating with a screw 9 fixed in the body 1 and forming a stop abutment.

The screw 9 permits, via its positioning in the groove 8, limiting the displacement of the casing 2, and a plug 10, which may advantageously be formed from a synthetic material, is intended to prevent any undesired access to the screw 9.

The casing 2 is moreover provided on its generatrix with two diametrically opposed conical holes 11 cooperating with two conical-headed screws 12 fixed in the body 1 and displacing the casing 2 in the direction of the base of the bore of the body 1, and on its face directed toward the base of the bore of the body 1, at regular intervals, with holes 13 for guiding and maintaining springs 14 loading this said face.

The device 3 for radial adjustment has the form of a shouldered cylindrical element of which the portion 15 of lesser diameter is provided with a helicoidal gearing 16 extending over the majority of its circumference, or over all its circumference, and is housed in the bore 5 of the casing 2, and of which the portion 17 of greater diameter is in the form of a disk housed in the bore 6 of the casing 2 and is provided with two diametrally opposed holes 18 for reception of pins 19 and 19' cooperating with transverse grooves 20 of the tools 21 to be adjusted, the device 3 being disposed freely rotatably in the casing 2 by means of a resilient ring 22 (FIGS. 1, 2, 7 and 8).

The means 4 for actuating the device 3 (FIGS. 2 and 4) is in the form of an endless screw positioned in a housing 23 of the casing 2 tangent and perpendicular to the bore 5 in meshing engagement with the helicoidal gearing 16 of the device 3, this screw 4 being provided at one extremity with an operable polygon in the form of a hexagonal recess 24, accessible through a hole 26 of the body 1, and a resilient ring 25 fixed on is other extremity assuring its maintenance in the housing 23. Lubrication of the connection between the endless screw 4 and the helicoidal tooth 16 is assured by means of a grease cap 27 (FIG. 4).

The pins 19 and 19' are force-fitted or glued in the holes 18 of the portion 17 of greater diameter of the device 3, and one of the pins 19 is mounted projecting toward the corresponding tool 21 and flush with the lower face of the portion 17, whereas the other pin 19' projects from both sides of the portion 17, at a height equal to about half of that by which projects the pin 19 and corresponding to the possible axial displacement of the casing 2 in the bore of the body 1, and penetrates, at its lower portion, into the circular arc-shaped groove 7 of the casing 2, and at its upper portion in the transverse groove 20 of the corresponding tool 21.

Thus, the groove 7 serves as an abutment for the device 3 in the two possible directions of rotation. Moreover, in the upper position of the casing 2, the pins 19 and 19' penetrate into the grooves 20 of the corresponding tools 21, whereas in the lower position of the casing 2, pressing against the action of springs 14 under the gripping force of the screws 12, the pin 19' is no longer in the corresponding groove 20, only the pin 19 remaining partially in the groove 20 to which it corresponds.

The tools 21 are preferably plate holders, and the pins 19 and 19' permit their displacement through the intermediary of the grooves 20.

The springs 14 are intended to apply a constant pressure upwardly of the casing 2 which is retained axially and in rotation thanks to the groove 8 cooperating with the screw 9. Moreover, the spring 14 are guided in deep holes 14' provided in the body 1.

So as to effect symmetrical adjustment of the plate holders 21, the pins 19 and 19' must penetrate into the grooves 20 of the said plate holders 21. First, the casing 2 is arranged in lower position against the action of the springs 14 by screwing of the screws 12 into the holes 11, then the plate holder 21 corresponding to the pin 19 is introduced into the body 1 up to correspondence of its groove 20 with the said pin 19, and next the second plate holder is similarly positioned.

The screws 12 are then unscrewed so as to permit upward displacement of the casing 2 under the pressure of the springs 14, and the second plate holder 21 is displaced so as to permit penetration of the corresponding pin 19' in its groove 20.

When this operation is performed, the screws 28 for leveling the plate holders 20 are tightened slightly and the screw 29 for securing the plate holders in the body 1 is positioned. The endless screw forming the means 4 is then actuated by means of a key and drives the device 3 in rotation in one direction or the other so as to effect the displacement of the plate holders 21 by means of the pins 19 and 19'. Once the requisite setting, measured by means of a slide caliper or any other suitable device, is attained, the plate holders 21 are blocked by means of the wedging screws 28 and the tightening screw 29.

It is also possible to perform a separate or independent adjustment of the plate holders 21 as well as an adjustment in height of one plate holder. To this end, the head is mounted via a preadjustment bench and the central tightening screw 29 is unscrewed and the screws 28 are also slightly unscrewed, then the screws 12 are tightened so as to displace the casing 2 downwardly in the bore of the body 1 against the action of the springs 14 and so as to disengage one of the plate holders 21 entirely from the corresponding pin 19', this plate holder thus being able to be adjusted simultaneously in height. Then the other plate holder 21 is displaced by means of the endless screw 4 acting on the device 3 until it attains the desired setting. Next, the first plate holder 21 is manually adjusted such that it is offset with respect to the other by a width about equal to half the width of the cuttings to be removed. After this radial displacement, the axial displacement of this plate holder, for obtaining the offset in height with respect to the other, is effected in the manner described in France No.A-2 563 132, then the screws 28 and 29 are once again tightened.

On the other hand, the drilling head is provided, in a known manner, with channels 30 for lubrication of the tools.

FIG. 9 shows a variation of the invention, in which the device 3 for radial adjustment of the tools 21 is mounted in the body 1 with the possibility of axial displacement under the action of the actuating means 4', and is constituted in the form of a drive wheel 31, movable in rotation and cooperating, by means of pins 19 and 19', with transverse grooves 20 of the tools 21 to be adjusted in order to displace in one direction or the other these latter with respect to one another.

The pins 19 and 19' are force-fitted or glued in the corresponding holes of the wheel 31.

The wheel 31 comprises, on the side opposite the tools 21, a rod 32 provided near its free extremity with a wide circumferential groove 33 for maintaining its height in the body 1, and into which penetrates a stop screw 34 for limiting the axial displacemnt of the wheel 31 (FIGS. 9 and 12).

The means 4' for effecting axial displacement of the device 3 as constituted by a cam screw 35 extending orthogonally to the axis of the wheel 31 and having in its median portion a clearing of which the extremity opposite to the threading of the screw 35 is in the form of a cone 36 which cooperates with a cone 37 provided on the rod 32 of the wheel 31 between the groove 33 and the said wheel 31, a pin 38, projecting slightly from the housing of the cam screw 35, limiting the displacement of this latter in the direction of removal of its cone 36 from the cone 37 of the wheel 31 (FIG. 11).

The cam screw 35 is provided, in a known manner, with a hexagonal recess for its operation.

The free end of the rod 32 of the wheel 31 is loaded by an axial spring 39 housed in a bore 40 of the body 1 (FIG. 9).

Thus, upon rotation of the cam screw 35, the wheel 31 is displaced thanks to the cooperation of the cones 36 and 37, the spring 39 exerting a continuous pressure on the rod 32 tending to displace the wheel 31 in the direction of the tools 21, the course of this displacement being limited by the stop screw 34.

The drive wheel 31 is driven in rotation by means of an adjustment screw 41 extending orthogonally to the rod 32 of the wheel 31, driving a stud 42 provided with a housing 43 cooperating with one of the pins 19 traversing to this end the wheel 31, and maintained in its housing 44, against translation, by means of a pin 45 cooperating with a throat 46 provided at its end (FIGS. 9 and 12).

Operation of the screw 41 is advantageously performed by means of a hexagonal recess 47, and the head 48 of the screw has a conical surface provided with graduations 49 (FIG. 11). Thus, rotation of the wheel 31 by operation of the screw 41 drives a displacement of the tools or plate holders 21 by means of the pins 19 and 19', one of which, 19, is driven by the stud 42 at the time of its displacement along the screw 41.

The graduations 49 provided on the conical surface of the head 48 of the screw 41 are intended to facilitate adjustment or displacement of the plate holders or tools 21.

Thanks to the invention, it is possible to perform a simultaneous and symmetrical displacement of two tools or plate holders in their housing of a body for fastening through the intermediary of a single adjustment screw. The displacement or the diameter of the said tools or plate holders can be easily measured by means of a slide caliper or a micrometer gauge, and the finest necessary adjustments are facilitated thanks to the graduations 49 of the adjustment screw 41.

The symmetrical and simultaneous displacement of the plate holders or tools 21 is performed when the drive wheel 31 has its surface directed toward the plate holders at the level of the bearing surface of these latter, that is to say when the cone 36 of the cam screw 35 is in its entirely retracted position with respect to the cone 37 of the rod 32 of the wheel 31.

It is also possible to perform an independent displacement of the tools or plate holders 21. To this end, each tool 21 is positioned on a different diameter, and that corresponding to the drive pin 19' is advantageously offset in height with respect to the other by about 0.5 mm or more, this latter tool being moreover positioned on a smaller diameter than that corresponding to the pin 19.

For this asymetric height adjustment, the drive wheel 31 will be pushed completely against the spring 39, and thus recessed from the bearing plane of the plate holders or tools 21, such that the pin 19' is no longer engaged in the corresponding groove 20, only the pin 19 remaining engaged. Displacement of the plate holder or tool 21 corresponding to the pin 19 is thus always effected through the intermediary of the adjusting screw 41, whereas that of the other tool or plate holder will be effected manually.

Rotation of the drive wheel 31 is limited by the possible displacement of the drive stud 42.

For mounting tools or plate holders 21, the drive wheel 31 must always be brought to its retracted position in the body by means of the cam screw 35, the tool 21 corresponding to pin 19 being first introduced and, following the foreseen machining process, the drive wheel is then freed or not for axial displacement.

According to another variation of the invention, not shown in the accompanying drawings, the wheel 31 may advantageously be provided on its surface direction toward the rod 32 with a conical toothed ring intended to cooperate with a conical adjustment pinion or key, removable if desired, a locking screw maintaining the wheel 31 in position after adjustment. Such an embodiment permits doing away with the adjustment screw 41 with its accessories.

Thanks to the invention, it is possible to realize a drilling head permitting great flexibility of use due to its various possible simple adjustments, while conserving a requisite strength of the assembly and maximum performance. Moreover, the invention permits doing away with a significant number of adjustment screws and thus also the corresponding keys, the adjustment and symmetrical displacement of two plate holders being able to be effected with only one screw and one key, with a very simple control instrument.

It will be understood that the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications remain possible, particularly from the point of view of the constitution of the various elements, or by substitution of equivalent techniques, without departing whatsoever from the scope of protection of the invention.