GB1604825A

GB1604825A - Means for holding punches and similar shanked tools

Info

Publication number: GB1604825A
Application number: GB3142777A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-12-16

Description

(54) IMPROVEMENTS IN OR RELATING TO MEANS FOR HOLDING PUNCHES, AND SIMILAR SHANKED TOOLS (71) 1, MICHAEL JOHN WARNER, a British Subject, of 21 Belgrade Road, Hampton, Middlesex, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to means for holding punches and similar tools having a shanked portion for reception in a socket provided for example in another tool or in the body of a machine such as a press or the like.

In small engineering works in particular, one of the prevailing difficulties is that punches and similar tools made for fitting to the machine of one particular manufacturer cannot be fitted to a similar machine made by another manufacturer owing to the disparity in dimensions of the shanks on the tools themselves. Unless the shank fits the tool-receiving chuck or socket in the machine, or in an auxiliary member such as a receiver, it will be apparent that the tool cannot be properly held if the clearance is too great, and obviously if the shank is too large for the chuck socket it cannot even be offered up to it.

Another difficulty which arises is the accurate positioning of a workpiece in relation to the axis of the punch and die.

It is, therefore, an object of the invention to provide means whereby punches and other shanked tools normally provided for punching machines are enabled to be used with machines made by manufacturers different from those manufacturing the tools themselves, or in simpler hand or lightpowered machines such as fly presses or socalled power presses.

Accordingly the invention consists in an adaptor for use in mounting shanked tools to a machine tool, the adaptor comprising, in combination, a holder member having an axial boss and a stepped internal bore for receiving a shanked tool, and a head piece having a shank which can be inserted in a machine tool and a bore in which the boss of the holder is a close fit, the holder and the head piece having indexing means whereby the orientation of the holder with respect to the head piece may be varied to accommodate non-symmetrical punches.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings, in which: Fig. 1 is an exploded side view of an adap tor according to the present invention, Figs. 2, 3, 4 and 5 are four different kinds of punch for use with the adaptor of Figure 1, Fig. 6 is an exploded side view of parts of a bolster press assembly for use with the adaptor of Fig. 1 according to the invention, and Fig. 7 is a perspective view of the assembly shown in Figure 6.

Referring to the drawings, a holder 1 having a circular cross-section is provided with a boss 2 to fit an internal bore 3 in a head piece 4, the head piece 4 having a shank 5 by means of which it can be held in a press. The holder 1 is also provided with a dowel 6 which is arranged to fit in one of three bores 7 in the head piece 4. The three bores 7 (only one being shown) are arranged to span an arc of 90" in a symmetrical manner about the central axis of the head piece so that the orientation of a tool held in the holder can be varied by 45" or 90" at will by altering the position of the holder 1 with respect to the head piece. Furthermore the head piece 4 has a threaded bore 8 in which a movable dowel 9 can be pressed against the boss 2 by a screw 10 to hold the head piece 4 and holder 1 together. The holder I has an internal bore 11 stepped at 12 to provide an increased diameter bore 13, the latter being provided with a flat 14 in order to be able to orientate a punching tool which may be held by the holder 1. The reason for this is that in operation it is necessary for the position of a tool which is non-circular in cross-section to be accurately fixed so that in use it is properly in register with a die fitted in or on a bolster on the machine bed beneath the punch. It will be appreciated that some tools are symmetrical and will have a shank which is circular in cross-section whilst others have flats on their shanks and thus have to be correctly oriented with respect to the holder 1, to the press in which the latter is mounted and to the die. Thus to locate the shanks of punches having flats there is provided a cylindrical insert 20 having a dowel 21 locatable in a bush 22 in the holder. The insert 20 has associated with it a pair of loose dowels 23 in the form of small cylinders which locate accurately in the interior of the insert 20 and act themselves to locate the flats of a tool shank inserted into the insert 20. The bore 13 in the holder 1 is intended to receive different collars such as collar 30. All the collars will be a close fit in bore 13 and have a central hole 31 through which the shank of a tool passes. Each collar also has a flat corresponding with flat 14 and is held in place in holder 1 by a screw 33. The collar 30 also has a bush 34 the purpose of which will be described hereinafter. Various kinds of tool which can be used with the holder described are shown in Figs. 2-5.

For example in order to accommodate the largest punch available, either of circular or non-circular cross-section, the holder is attached to a circular plate 40 having a dowel 41 which locates in the bush 34 in collar 30, the plate 40 having a centre locater 42 to locate the punch in the bore and also being provided with a slot 43 which is used to locate an appropriate dowel on the punch to ensure correct orientation of the latter if it is a shaped punch.

For operation of the punch tool either in a fly press or a power press as referred to above, means must be provided to strip the work piece away from the tools as the punch is separated from the die and for this purpose stripper units of various shapes and configuration are provided.

Primarily, the stripper units comprise an upper plate to be connected to the holder 1 and a lower annulus separated by compression spring means which may comprise compression springs centered around connecting bolts or resilient blocks such as natural or synthetic rubber, depending upon the relative sizes of the parts and the compression strength required. In operation, the stripper unit is secured to the holder and on the downward stroke of the punch, the annulus impinges on the work piece just before the punch contacts it and retains the work piece in position during the return stroke of the punch until the punch has cleared the die.

The invention enables the comparatively little-used tools of a heavy duty punching machine to be accommodated in a fly press or power press for short production runs so that the tools are therefore used to maximum advantage without their standing idle, and secondly avoiding the special manufacture of punch tools for small production runs for use in the fly press or power r press.

As will be apparent to those skilled in the art, the die is incorporated in a bolster assembly located on the machine to be beneath the punch. As shown in Fig. 6 a die will sit within a circular opening in a cast base 50 so as to project upwardly through an aperture in a rectangular top plate 51. The upper face of the projecting die will be substantially coplanar with the upper face of the plate 51.

With the passage of time dies become worn and their upper faces have to be re-ground or otherwise re-worked to remove the work portions. Such re-grinding clearly reduces their thickness. Instead of packing out the die from below, the embodiment shown in Figure 6 employs an alternative method.

Thus the top plate 51 is provided at its four corners with four columns 53 which are slidable in corner holes 54 in the base 50.

The plate 51 is held in a fixed plane by four locking screws which cooperate with the columns 53, two of these locking screws being shown at 55.

The upper surface of the base 50 is further provided with four additional holes 56 in which are housed compression springs which project beyond the upper surface of the base 50.

To match up the upper surface of the plate 51 to a re-ground die, it is only necessary to slacken locking screws 55, press the plate 5 against the pressure of the springs, perbaps by using the press, and retightening the locking screws. Sometimes a die is of smaller diameter than that of the recess in the base 50. In this event, one or more filler rings such as 60 and 61 may be provided, the filler rings being held in the correct position by dowels 62, 63 which dowels locate in slots in side and/or base assembly. Naturally the number of filler rings can b increased to match the number of different dies available.

It will be appreciated that during a punching operation it is of the greatest importance that the work piece be accurately positioned in register with the centre line of the die and associated punch.

For this purpose the filler ring 60 is formed with four bushes 70, spaced at 900 around the periphery of the filler ring and each of these bushes receives a dowel 71 which projects above the surface of the plate 51 when the filler ring is located in its operative position in the recess in the base 50.

Each bush 70 is accurately located so that a tangent can be taken from the surface of the dowel in the bush, which tangent extends to the exact central axis of a die held either within the ring insert 60, or held by a series of ring inserts. Thus a set of imaginary orthogonal axes can be drawn from the die centre with each axis a tangent to the surface of a dowel 71.

The dowels 71 provide measurement points for a Vernier scale which may be carried on an extension plate 80. The extension plate 80 is made from a number of parallel angle plates 82 held together by transverse bars 82 so as to leave longitudinal slots and carries a stop 83 which is adjustable along a line formed by one of the longitudinal slots towards and away from the die centre by a clamping arrangement indicated comprising a nut 81 on a screw-threaded bolt (not shown). The stop 83 carries a further adjusting screw 84 connected to a member 85 having a flat end face 86. The extension plate 80 is screwed to the top plate 51 by a pair of screws 87 and is arranged to be mountable on one of three sides of the top plate as shown in dotted lines in Figure 7.

This enables work pieces of widely differing dimensions to be readily accommodated.

WHAT I CLAIM IS: 1. An adaptor for use in mounting shanked tools to a machine tool, the adaptor comprising, in combination, a holder member having an axial boss and a stepped internal bore for receiving a shanked tool, and a head piece having a shank which can be inserted in a machine tool and a bore in which the boss of the holder is a close fit, the holder and the head piece having indexing means whereby the orientation of the holder with respect to the head piece may be varied to accommodate non-symmetrical punches.

2. An adaptor as claimed in claim 1, wherein the indexing means comprise a dowel provided on either the head piece or the holder and adapted to cooperate with one of a plurality of bushes angularly spaced about the central axis of the other member.

3. An adapotr as claimed in either claim 1 or claim 2 in combination with a bolster press for punch and die apparatus, comprising a base having a circular recess, a top plate supported on the base and having a circular aperture coaxial with the recess, a filler ring locatable in said recess and within said aperture for locating a die, said filler ring having a plurality of dowels projecting therefrom at locations selected in relation to the axis of said recess so that each dowel provides a measurement point relative to the recess axis.claimed in axis.

4. A combination as claimed in claim 3, wherein the bolster press includes at least two dowels on the filler ring which are diametrically opposed.

5. A combination as claimed in claim 3 or claim 4, wherein the top plate of the bolster press is mounted on the base by means of a plurality of columns slidable in bores in the base whereby the height of the top plate relative to the base may be adjusted, each bore having associated therewith screw means for locking the column received therein in a desired position.

6. A combination as claimed in claim 5, wherein the bolster press includes compression spring means located between the top plate and the base.

7. A combination as claimed in claim 6, wherein the bolster press includes an extension plate mounted adjacent the top plate so that the upper surface of the two plates lie in the same plane.

8. A combination as claimed in claim 7, wherein said extension plate is secured to said top plate by means which allow it to be positioned in a plurality of different positions relative to the top plate.

9. A combination as claimed in claim 8, wherein the extension plate carries a member having a stop face against which a work piece may be positioned, the position of the member being adjustable on the extension plate.

10. A combination as claimed in claim 8, wherein the stop face is adjustable with respect to said member by screw means.

11. A combination as claimed in claim 9, and including vernier scale means associated with said stop face.

12. An adaptor as claimed in any one of claims 1, 2, or 3 in combination with a bolster press as shown in Figs. 6 and 7.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. drawn from the die centre with each axis a tangent to the surface of a dowel 71. The dowels 71 provide measurement points for a Vernier scale which may be carried on an extension plate 80. The extension plate 80 is made from a number of parallel angle plates 82 held together by transverse bars 82 so as to leave longitudinal slots and carries a stop 83 which is adjustable along a line formed by one of the longitudinal slots towards and away from the die centre by a clamping arrangement indicated comprising a nut 81 on a screw-threaded bolt (not shown). The stop 83 carries a further adjusting screw 84 connected to a member 85 having a flat end face 86. The extension plate 80 is screwed to the top plate 51 by a pair of screws 87 and is arranged to be mountable on one of three sides of the top plate as shown in dotted lines in Figure 7. This enables work pieces of widely differing dimensions to be readily accommodated. WHAT I CLAIM IS:

1. An adaptor for use in mounting shanked tools to a machine tool, the adaptor comprising, in combination, a holder member having an axial boss and a stepped internal bore for receiving a shanked tool, and a head piece having a shank which can be inserted in a machine tool and a bore in which the boss of the holder is a close fit, the holder and the head piece having indexing means whereby the orientation of the holder with respect to the head piece may be varied to accommodate non-symmetrical punches.