GB2147834A

GB2147834A - Grinding device

Info

Publication number: GB2147834A
Application number: GB08425205A
Authority: GB
Inventors: Hansgeorg Hampel
Original assignee: Deutsche Telephonwerke und Kabelindustrie AG
Current assignee: Deutsche Telephonwerke und Kabelindustrie AG
Priority date: 1983-10-13
Filing date: 1984-10-05
Publication date: 1985-05-22
Also published as: DK488284A; NL8402694A; LU85505A1; GB2147834B; BE900755A; IT1176946B; GR80605B; FR2553324A1; DE3337487A1; GB8425205D0; IT8423124A0; DK488284D0

Abstract

A grinding device for grinding a channel in a conical aperture 19, comprises: a tubular head 14 having an axis which is oriented to define the grinding direction and which receives a high speed rotatable grinding tool shaft 18; and reciprocable drive means 15, operable to reciprocate a pivoted link 16 thereby to rotate the head 14 through a predetermined limited angle about its axis, the head 14 and the grinding tool shaft 18 being 50 coupled together that when the drive means 15, 16 operates, the consequent rotation of the head 14 will cause the grinding tool 18 to advance to execute a grinding stroke. <IMAGE>

Description

SPECIFICATION A grinding device This invention relates to a grinding device and is particularly, but not exclusively, applicable to a grinding device for grinding slanting cuts in conical walls of round apertures in cutting plates.

An automatic punching machine or the like, for example an eccentric or hydraulic press, or a stamping machine, comprises an apertured plate or die and a cooperable punching tool. A strip of material to be punched is located between the apertured plate and the punching tool, and the latter descends rapidly through the strip of material into a conical aperture in the plate to punch out of the material an element corresponding in shape to that of the aperture. The punched-out element can either be a finished part which is retained, or a waste element which may be discarded. In each case the punched-out element should either drop through its forming aperture, or be cleanly pushed out of it by the tool in its punching stroke.

The apertures in the cutting plate or die are formed conically to facilitate the falling-through of the cut-out parts. To prevent the upwards pullingout from the apertures of the cut-out parts by the punching tool, it has been proposed in secret that all the apertures of the cutting plate or die be additionally provided with two oppositely located slanting cuts which are arranged at a specific angle to the stamping direction (our co-pending British patent application No. 8419817). The cuts form projections on the punched-out element thereby to reduce the tendency of the element to be lifted out of the aperture by the movement out of the aperture of a punching or pressing tool during its return stroke.

According to the present invention there is provided a grinding device for grinding a channel in a workpiece, comprising: a head having an axis which is oriented to define the grinding direction and which receives a grinding tool; and drive means operable to rotate the head through a predetermined limited angle about its axis.

For a better understanding of the invention and to show how it may be put into practice reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 shows a conical aperture, with slanting cuts, in an apertured cutting plate for a punching machine; Figure 2 is a section along line 3-3 of Fig. 1; and Figure 3 shows in perspective a device for grinding the slanting cuts in the conical aperture.

Figures 1 and 2 show a conical aperture 19 in a apertured cutting plate for a punching machine.

The angle of conicity of the aperture is angle A.

In operation of a punching machine, a sheet of metal is laid on the horizontal cutting plate at the narrowest end of the aperture 19. A punch enters the aperture 19, carrying with it a punched-out element from the sheet of metal. The outward flare of the aperture 19 encourages the punched-out element to drop through the aperture 19 and fall away.

Sometimes, however, the punched-out element is carried out of the aperture 19 upwardly with the punch on its return stroke. To overcome this, cuts 20 and 21 are provided on opposite sides of the aperture 19. These cuts form projections on the punched-out element, which projections act to prevent the element being lifted with the punch on its return stroke.

Figure 3 shows a grinding device which, among other things, is operable to grind the slanting cuts 20 and 21 into the wall of the aperture 19.

The device shown in Figure 3 comprises a controller 11 and is secured to a co-ordinate grinding machine 10 (not shown in detail) which provides a high-speed rotary drive via a flexible drive shaft (not shown).

A punching machine cutting plate comprising the conical aperture 19 is secured on a working surface ready to have the slanting cuts 20, 21 ground into it by means of a high-speed rotary shaft 18 which carries a diamond grinding element at its working tip.

The shaft 18 extends within, and all the way along, a tubular head 14 along the axis of the latter. At the top end of the head 14 the shaft 18 emerges and its top end is secured to the aforementioned flexible drive shaft which is driven in rotation by the grinding machine 10. The top end of the head 14 and associated parts are not shown, for the sake of clarity.

The shaft 18 is driven downwardly to grind the cuts 20, 21 in a maner which will be described hereinafter, and the angle of the shaft relative to the axis of the aperture 19 depends upon the orientation of the head 14.

Clearly the head 14 (and the shaft 18) must lie at the angle A with respect to the axis of the aperture 19 if the cuts 20 and 21 are to be made in the direction of the conical wall of the aperture 19.

The head 14 can be inclined at this angle A to the vertical by the whole grinding device being pivoted by this angle A about an axis extending parallel to the longitudinal extent of the device away from the grinding machine 10. Alternatively, the plate containing the aperture 19 could be mounted in such a way that it could be angled to provide that the axis of the head 14 and the shaft 18 extend parallel to the wall of the conical aperture 19.

Once the angle A has been adjusted, it is necessary to adjust the head 14 to extend at the angle B in a plane perpendicular to that containing the angle A.

In order to achieve this the grinding device comprises a fixed plate 12a to which the remainder of the grinding device is coupled so as to be pivotable about an axis which is perpendicular to the longitudinal extent of the device away from the grinding machine 10. When this remainder of the grinding device is pivoted about this axis, the angle B can be read directly from a scale on an adjustment member 12 for the angle B, which angle depends upon the diameter of the aperture 19.

The adjustment member 12 is rigidly coupled to a guide device 13 comprising a compressed air cylinder 15 having a movable piston which is coupled via a rigid linkage to a lever 16 which is pivotably coupled to the end of the rigid linkage.

Operation of the compressed air cylinder 15 drives the lever in a horizontally extending groove 17 in the directions of the arrows.

The lever 16 is rigidly connected to the head 14, which contains the shaft 18. A rotary bearing houses the shaft 18 within the head 14, whereby the shaft 18 can rotate relative to the head 14, and vice versa.

When the compressed air cylinder 15 is set into operation by means of electropneumatic valves which are not shown, the head 14 rotates from its rest position through a range of 60 in each direction, making 1200 in all. This is caused by the lever 16 being moved forwards and backwards in the directions of the arrows in the horizontally extending groove 17.

The lever 16 is rigidly connected to the head 14, at one end, and at its other end pivots about the illustrated axis at the end of the linkage from the compressed air cylinder 5.

The rotary bearing between the shaft 18 and the head 14 not only allows the head 14 to be rotated about the already rapidly-rotating shaft 18, but it is fixed by its inner race at a particular longitudinal region on the shaft 18. Its outer race on the other hand can slide upwards and downwards to a limited extent along the inside of the tube forming the head 14.

This outer race and the adjacent inner surface of the head 14 comprise cooperable helical or thread means (not shown) which cooperate such that when the head 14 is rotated by the lever 16, the cooperable helical or thread means operate to drive the whole of the rotary bearing downwards or upwards along the inside of the head 14, and the rotating shaft 18 with it.

Thus the rotational movement of the head 14 by the lever 16 causes the shaft 18 and the rotary diamond to be lowered down at the angles A and B to grind the slanting cuts 20 and 21 of constant depth, then lifted. This process can be repeated a plurality of times according to the desired grinding depth perpendicular to the aperture wall.

Preferably, the grinding device is employed for the exact grinding of slanting cuts such as 20 and 21 in circular apertures such as 19 with diameters larger than 0.8 mm, in order to achieve specific angles of the slanting cuts in the aperture wall.

However, it will be appreciated of course, that the grinding device could be employed for other, similar, grinding tasks also.

Claims

1. A grinding device for grinding a channel in a workpiece, comprising: a head having an axis which is oriented to define the grinding direction and which receives a grinding tool; and drive means operable to rotate the head through a predetermined limited angle about its axis.

2. A grinding device according to claim 1, wherein the head and the grinding tool are so coupled together that when the drive means operates, the consequent rotation of the head will cause the grinding tool to advance to execute a grinding stroke.

3. A grinding device according to claim 1 or 2, wherein the head and the grinding tool are so coupled together that the tool can be driven in rotation rapidly with respect to the head.

4. A grinding device according to any preceding claim, wherein said drive means is operable to rotate the head through a predetermined limited angle of substantially 60 in both directions.

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5. A grinding device according to any preceding claim, wherein said drive means comprises an electropneumatic drive device which is coupled to the head via a lever, which is guided in a substantially rectilinearly extending groove and which is rigidly connected to the head.

6. A grinding device according to any preceding claim, comprising first adjustment means operable to adjust the head so that the grinding direction will be at a predetermined angle B, to a reference direction, in a first predetermined plane.

7. A grinding device according to claim 6, comprising second adjustment means operable to adjust the head so that the grinding direction will be at a predetermined angle A, to a reference direction, in a second predetermined plane substantially at right angles to the first predetermined plane.

8. A grinding device according to any preceding claim, which is an attachment for a co-ordinate grinding machine which can be used to drive the grinding tool.

9. A grinding device according to any preceding claim, which is adapted and arranged for grinding slanting cuts in the conical wall of an aperture in a cutting plate for an automatic punching machine or the like.

10. A grinding device according to claim 9 when appended to claim 6, or when appended to claim 7 or 8 and claim 6, wherein the predetermined angle B is the angle of the slanting cuts with respect to the axis of the aperture.

11. A grinding device according to claim 9 or 10 when appended to claim 7, or claims 7 and 8, wherein the predetermined angle A is the angle of conicity of the aperture.

12. A grinding device substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

13. Device for grinding slanting cuts in conical walls of round apertures in cutting tools for automatic punching machines, eccentrics and hydraulic presses, characterised in that the device secured on a co-ordinate grinding machine 10 has a guide device (13) which guides a lever (16) in a horizontally lying groove (17) by means of electro-pneumatic control means with a forwards and backwards movement, which lever is rigidly connected to the grinding spindle pick-up attachment (14) for the grinding pin (18), so that through the movement of the lever, the grinding spindle pickup attachment (14) is rotated to two sides at an angle of 60 respectively.

14. Device according to claim 13, characterised in that the guide device (13) is coupled to an adjustment device (12) which allows the adjustments of the angles (B) of the slanting cuts dependent on the size of the diameters of the round apertures.

15. Device according to claim 13, characterised in that for adjustment of the angle (A) of the conical form of the aperture walls, the grinding spindle pick-up attachment (14) is swivellably arranged.