US2847881A

US2847881A - Drilling machines

Info

Publication number: US2847881A
Application number: US417784A
Authority: US
Inventors: Allemann Hugo
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-03-30
Filing date: 1954-03-22
Publication date: 1958-08-19
Anticipated expiration: 1975-08-19
Also published as: CH320032A; FR1088998A; GB755518A

Description

Aug. 19, 1958 H. ALLEMANN DRILLING MACHINES 3 Sheets-Sheet 2 Filed March 22, 1954 Int eaten HUGO HLLEMANP/ Aug. 19, 1958 H. ALLEMANN 2,847,881

DRILLING MACHINES Fil ed March 22, 1954 s Sheets-Sheet 3 A L'Q (F -F7 l-slueo ALLA-MANN United States. Patent DRILLING MACHINES Hugo Allemann, Luterbach, Solothurn, Switzerland Application March 22, 1954, Serial No. 417,784 Claims priority, application Switzerland March 30, 1953 4 Claims. (Cl. 77-55) This invention relates to a guide device for drilling machines for aligning the tool and the workpiece in relation to one another in the drilling and counter-sinking of workpieces.

This device is intended to be used in place of the hitherto customary centre punching of the workpiece. The centre punch has the object of providing a guide for the point of the drill, since it is practically impossible to guide the drill mechanically or by hand accurately at a determined point. Any drill will slip if its point is not guided. The drill can as a rule be guided manually or mechanically on to the centre punch mark with an accuracy of a few hundredths of a millimetre, but not accurately into the centre. The exact guiding is then taken over by the centre punch. Particularly in the case of small holes, such as are used in the clock industry, for example, the centre punching nevertheless upsets and bends the material of the workpiece, that is to say damages it, thus considerably increasing the difficulty of subsequent manufacture.

The present invention aims at obviating these difiiculties and to this end, consists in a device for drilling machines for aligning the tool and workpiece characterised in that of the two parts to be aligned in relation to one another, namely the tool and the workpiece, and which are axially movable in relation to one another, one is guided radially movably in relation to the axis of the drilling, while the other is mounted to be immovable, and on both parts co-acting guide means are so disposed that through the co-operation of the guide means of the movable and fixed parts, on the axial movement of the same in relation to one another, the tool is aligned with respect to a predetermined point on the workpiece and the tool and workpiece are joined in such a manner as to be immovable in relation to one another.

In order that the invention may be more readily under stood, reference is made to the accompanying drawings, which illustrate diagrammatically and by way of example, several embodiments thereof, and in which:

Figure 1 is a vertical section through a drilling machine in the direction of the axis of the spindle, only parts necessary for the understanding of the invention being shown;

Figure 2 is a horizontal section on the line AA of Figure 1;

Figure 3 is a horizontal section of a modified embodiment on the line B-B of Figure 4;

Figure 4 is a vertical section on the line DD of Figure 3;

Figure 5 is a modification for drilling with drilling bushes, in vertical section on the line F-F of Figure 6;

Figure 6 is a horizontal section on the line E'-E in Figure 5;

Figure 7 is another modification in vertical section on the line MM of Figure 8; and

Figure 8 is a horizontal section on the line HH of Figure 7.

In Figure 1, 1 denotes the machine frame, in which a rotating sleeve 2 with a head 2 is mounted at 1 the ice sleeve having an internal bore of square cross section extending longitudinally over its entire length. The sleeve 2 is held at the top by an adjusting ring 3, and is rotated by means not shown. The working spindle 4 is provided at its top end with a square 4 which has a small clearance 'in the internal square in the sleeve 2 and has rounded edges in order that the working spindle 4 can perform a limited deflection in any direction. An adjusting nut 5 is screwed on a screw thread 4 on the working spindle and serves as a stop to receive the axial pressure against the sleeve 2 and for the longitudinal adjustment of the working spindle. The working spindle 4 is guided in a bush 6 inserted in a bore in the machine frame 1, four guide pins 7 being carried by said bush. A bush 8, which is inserted in the bore 1 has at its upper end four slots or groove 8 set at an angle of to one another and V-shaped at the bottom. The four guide pins 7 rest through the weight of the bush 6 in these grooves 8 so that the bush 6 always automatically slips back into its starting position. However, as soon as the bush 6 is displaced upwardly in the axial direction, until the guide pins 7 bear against a ring 10 loaded by a compression spring 9, the ring 10 is raised axially and the compression spring 9 compressed.

At the bottom end the bush 6 has a flange-like plate 6 This plate 6 can be made integral with the bush 6, or can be fastened on the latter as a separate part. The guide and connecting means between the plate 6 and the workpiece 12 can be in the form of locating pins, form guides, or both together. The plate 6 alone determines, starting from the starting points of the workpiece, the position for a hole to be drilled or a counterbore. For each drilling point in this embodiment one plate is required. The machine table 11 has a recess fitting the workpiece 12, and in it the workpiece is mounted. The workpiece is held down by a foot 13, which has a bolt 13 which in turn is under the pressure of a spring 14. In order to limit the longitudinal movement of the bolt 13 and to secure it against turning, it is provided with a groove 13 into which a screw 15 projects. Two locating pins 16 are fixed in the plate 6 and engage in the locating holes 12 in the workpiece, thereby connecting the coordinate plate 6 to the workpiece 12.

A bush 17 of insulating material is pressed into a bore in the machine frame 1, into the bottom of which an adjusting screw 18 is screwed, which strikes against a bolt 20 carrying a contact carrier 19. The bolt 20 is secured against turning by suitable means and drawn back against the adjusting screw 18. The contact carrier 19 carries a contact plate 21, which is in contact with the adjusting nut 5 which carries the working spindle 4 when the drill 22 applies no axial pressure, i. e. when no drilling is being done. The contact carrier 19 is connected by an electric conductor 23 to a control system (not shown).

Another bush 25 of insulating material, which is pressed into a bore in the machine frame, has at the bottom an adjusting screw 26 screwed into it. A contact carrier 27 is secured to a bolt 28, which is mounted to be longitudinally slidable in the bush 25 and is prevented from turning by means not shown. A spring (likewise not shown) urges the bolt 28 in the direction of the adjusting screw 26. Above the top face of the bush 6 the contact carrier 27 is furnished with a contact head 29, so that the bush 6 when pushed upwards strikes with its face against the contact head 29.

The operation of this embodiment is as follows: The machine table 11 with the workpiece 12 set in is brought by hand or mechanically into the drilling position with an axial deviation of some hundredths of a millimetre. This must be done so accurately that the points of the locating pins 16 dependably reach the locating holes in the workpiece 12. The machine table 11 has thus assumed the position shown in dotted lines in Figure 1. The foot 13 is also in the position shown in dotted lines. The machine table 11 is then brought close to the machine frame 1 or conversely in the axial direction to the working spindle 4. By moving the machine table 11 near the machine frame 1, the foot 13 is first made to press on the workpiece 12 through the action of the spring 14. By further raising the machine table, the locating pins 16 are made to penetrate into the locating holes 12 in the workpiece, until the pins bear on their shoulders. But before the locating pins can penetrate the locating holes in the workpiece, the bush 6 must by constraint be aligned with the working spindle 4 to such an extent that the locating pins coincide exactly with the holes. For this purpose the bush 6 with the guide pins 7 is raised-until the latter are lifted off the surfaces of the grooves 8 which surfaces are disposed in wedge fashion in relation to one another, and the bush 6 can freely swing out radially and the locating pins follow the locating holes. If the machine table, and hence also the bush 6 and the guide pins 7 are lifted further, the latter press from below against the ring 10 acted on by the spring 9. The action of the spring 9, together with the dead weight of the bush 6, should press the locating pins 16 into the locating holes in the workpiece as far as their shoulders.

If however the locating pins have not penetrated into the locating holes because of obstructions, such as cuttings or ridges on the workpiece, whereby the spring 9 woul be additionally compressed to the extent of the length of the locating pins, the bush 6 will be too high to the extent of the penetrating length of the locating pins, so that its top face makes contact with the contact head 29. At the moment when the locating pins should have penetrated up to their shoulders into the workpiece, an electric control current is passed from a source of current through a cut-off device (not shown), conductor 30, contact carrier 27, and contact head 29. If at that moment that locating pins have penetrated insufficiently or not at all into the locating holes, the face of the bush 6 will be in contact with the contact head 29 and will thus close the circuit from the source of current through the cut-off device, conductor 30, contact carrier 27, contact head 29, frame, source of current, and the machine is cut off immediately.

In order to ensure the exact maintenance of the coordinates, it is advisable, as shown in Figure 4, to cut a centre with a centre bit. If the plate 6 is made accurately, the control device correctly adjusted by theadjusting screw 26, and the abovementioned centre is cut, even the smallest errors in the coordinates is impossible.

In order further to improve the invention, a control system is provided which stops the machine if a drill breaks, which would otherwise result in defective workpieces. To this end the adjusting nut 5 mounted on the working spindle 4 has axial clearance of a few hundredths of a millimetre between the contact plate 21 and the head 2 of the sleeve 2, this clearance being adjusted by the adjusting screw 18. On commencement of the drilling, the axial pressure produced by the drill 22 raises the working spindle 4 with the adjusting nut 5, so that the latter is lifted off the contact plate 21 and presses against the head 2 of the sleeve 2. At the moment when the adjusting nut 5 is no longer in contact with the contact plate 21, so that the drill has already started to drill, a current impulse is passed from a source of current through the conductor 23, contact carrier 19, and contact plate 21. If at that moment the drill is in order, the circuit between the contact plate 21 and the adjusting nut 5 is broken. If however the drill has broken off or has been pushed back in the clamp, the spindle 4 is not raised at the moment of the current impulse, but has dropped down, so that the adjusting nut 5 is in contact with the contact plate 21 and closes the circuit from the source of current, through the cut-off device (not shown),

conductor 23, contact carrier 19, contact plate 21, adjusting nut 5, frame,- and back to the source of current. The cut-oft device is consequently operated and the machine is stopped.

Figures 3 and 4 illustrate a modification. In the drilling table 32 a workpiece 33 is partly let-in and is held by an intermediate bridge 34. A bolt 35 is pressed into this intermediate bridge and is provided with a head 35 against which a compression spring 36 acts, which thus presses the workpiece 33 against the drilling table by means of the intermediate bridge 34. The workpiece 33 is a solid round disc without holes. In the recess in the drilling table it has a clearance of some hundredths of a millimetre in diameter. The intermediate bridge also has a circular recess in relation to the drilling table and larger than the latter, the axis of said recess coinciding as far as possible with that of the recess in the drilling table 32. The surface of the recess in the intermediate bridge is longitudinally ribbed in order to secure the workpiece better against rotation. The recess in the drilling table 32 is an approximate guide for the workpiece 33, whilst that in the intermediate bridge is an absolutely accurate guide, since it is provided with locating

holes

37 and 37 The latter are intended to guide the locating pins 38, which are pressed into the plate 39. The plate 39 is made in one piece with the bush 39 and, like the bush 6 in Figure 1, can swing out a limited distance in any direction. The centre bit 40 turning accurately in the axis of the bush 39 can thus be aligned with the plate 39 and intermediate bridge 34, and cut a centre for guiding a drill at an accurately determined point in the workpiece 33.

Another modification is illustrated in Figures 5 and 6, which show how a form plate as workpiece can be drilled with drilling bushes. A workpiece 42 is partly let into the drilling table'41, once again with clearance. The workpiece 42 already has a hole 43, in which a locating pin 44 is guided. A coordinate plate 45 is pressed fast on to a bolt 46 which is axially slidable, is acted on axially in the downward direction by spring pressure, and is secured against turning. In addition to the locating pin 44 pressed into the plate 45, the plate 45 is provided with a shaped part 47, which partly guides the workpiece against its surface. The workpiece is thus guided by the locating pin 44 and the shaped part 47 of the plate 45. The latter has a drilling bush 48, through which the drill 49 drills into the workpiece. In this embodiment the guiding of the working spindle is rigid, because the plate it also rigid. On the'other hand, however, the workpiece 42 is slidable to a limited extent, so that it can be aligned by means of the plate 45.

Finally, the modification illustrated in Figures 7 and 8, which is also provided with a rigidly guided working spindle, will also be briefly discussed. A stripper 52 serves to strip the workpiece 51 from the locating pins 55. It is secured on a bolt 53, which under the action of a spring (not shown) is urged to push the holder against the workpiece. A distance pin 54 holds the stripper 52 suspended above the workpiece, so that the latter can be freely aligned against the locating pins 55 which are pressed into the plate 56. In the workpiece 51 a centre 57 has already'been cut in a previous operation by means of a centre bit, so that the drill 58 is guided.

The mode of operation of the different embodiments corresponds approximately to that in the case of devices in general use.

I claim:

1. In a drilling machine, in combination, a spindle adapted to carry a drill and having a journal portion; a bearing engaging said journal portion of said spindle to guide the latter for rotation; support means supporting said spindle and said bearing for movement in axial direction and for tilting movement so that the spindle axis may be oriented with a given point; drive means operatively connected to said spindle for rotating the latter within said bearing without preventing the tilting movement of said spindle and bearing; and means connected directly to said bearing for automatically bringing during movement of said bearing in axial direction the axis of said spindle and a straight line passing through the workpiece into coincidence so that a drill carried by said spindle will drill in the workpiece a hole having an axis coinciding with the spindle axis and the straight line.

2. In a drilling machine, in combination, a spindle adapted to carry a drill and having a journal portion; a bearing engaging said journal portion of said spindle to guide the latter for rotation; support means supporting said spindle and said bearing for movement in axial direction and for tilting movement so that the spindle axis may be oriented with a given point; drive means operatively connected to said spindle for rotating the latter within said bearing without preventing the tilting movement of said spindle and bearing; radial positioning means connected directly to said bearing for automatically radially positioning during movement of said bearing in axial direction said bearing and spindle with respect to a workpiece; and axial positioning means connected to said radial positioning means for axially positioning said bearing with respect to a workpiece.

3. In a drilling machine, in combination, a spindle adapted to carry a drill and having a journal portion; a bearing engaging said journal portion of said spindle to guide the latter for rotation; support means supporting said spindle and said bearing for movement in axial direction and for tilting movement so that the spindle axis may be oriented with a given point; drive means operatively connected to said spindle for rotating the latter within said bearing without preventing the tilting movement of said spindle and bearing; a flange fixed to and extending radially outwardly from said bearing, said flange having a face which is directed downwardly when said spindle and bearing extend substantially vertically with a drilled carried "by said spindle extending downwardly therefrom; and a plurality of positioning pins respectively fixed to spaced portions of said flange, extending from said face thereof, and each having an annular shoulder spaced from and directed away from said face, all of said shoulders being located in a plane normal to the spindle axis.

4. In a drilling machine, in combination, a spindle adapted to carry a drill and having a journal portion; a bearing engaging said journal portion of said spindle to guide the latter for rotation; support means supporting said spindle and said bearing for movement in axial direction and for tilting movement so that the spindle axis may be oriented with a given point; drive means operatively connected to said spindle for rotating the latter within said bearing without preventing the tilting movement of said spindle and bearing; a flange fixed to and extending radially outwardly from said bearing, said flange having a face which is directed downwardly when said spindle and bearing extend substantially vertically with a drill carried by said spindle extending downwardly therefrom; a plurality of positioning pins respectively fixed to spaced portions of said flange, extending from said face thereof, and each having an annular shoulder spaced from and directed away from said face, all of said shoulders being located in a plane normal to the spindle axis; and spring means operatively connected to said bearing for urging the same toward a workpiece so that said pins may extend into openings of a workpiece to bring a predetermined point of the workpiece and the spindle axis into coincidence and so that said shoulders may press against the workpiece to position the bearing and workpiece axially with respect to each other as well as to guarantee that the spindle axis extends normally through the workpiece.

References Cited in the file of this patent UNITED STATES PATENTS 1,159,196 Eden Nov. 2, 3.915

1,814,920 Hartwell July 14, 1931 2,070,463 Allemann Feb. 9, 1937 2,625,062 Heil Jan. 13, 1953 FOREIGN PATENTS 802,768 Germany Feb. 22, 1951