US3191525A - Coining presses - Google Patents

Description

June 9 H. D. CHALLEN ETAL 3,191,525

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- Invem'b owrs M R R9 United States Patent 3,191,525 COlNlNG PRESSES Henry Denis Challen, Birmingham, and Denis Ralph Cooper, Surrey, England, assignors to Taylor & Challen Limited, Birmingham, England, a British company Filed June 12, 1963, Ser. No. 287,435 Claims priority, application Great Britain, June 15, 1962,

4 Claims. (Cl. 101-4) This invention relates to coining presses, that is to say, presses of the kind in which .a blank or workpiece is squeezed in a confined space between dies to impress on its surfaces the shape of patterns carried in the surfaces of the dies. Such presses are normally used for applying the impressions to the faces of coins and medals but they can be used for other purposes.

Although ordinary stamping and forging presses frequently have multiple dies it has hitherto been usual for coining presses to have only single dies because, in contrast to ordinary presses, coining presses have to apply a very closely controlled blow to the blank and it is normally impossible to ensure that two or more pairs of dies situated in different areas of the bed of the press strike exactly equal blows. Furthermore any variations in the thickness of the blanks will lead to variations in the depth of the impressions between one blank and another.

According to the invention this difficulty is overcome by providing a multiple die coining press in which either the upper or the lower dies are all mounted together in a carrier which can rock to allow the dies to align themselves automatically in a manner such as to distribute the force evenly between the dies. In this way the blanks receive equal blows even if the thicknesses of the blanks vary or if one die is set slightly higher or lower than another.

According to a further important feature of the invention the carrier is arranged to rock about a point which is in the plane of contact of the dies and is at the mean centre of the dies. This can be achieved by providing the carrier with a convex part-spherical or part-cylinder surface having this point as its centre or axis of curvature, and the carrier is received in a concave surface of the same shape.

The invention is preferably applied to the upper dies, the carrier being then mounted in the moving slide. In a preferred embodiment there are only two pairs of dies, side by side, and the axis of curvature of the surfaces passes perpendicularly through the midpoint of a line joining the faces of the two dies. The two upperdies are held rigidly in the carrier and the upper convex cylindrical surface of the carrier engages a concave cylindrical surface in the underside of the slide or platen of the press. The carrier is held resiliently against this surface by screws with helical coil compression springs under their heads.

The carrier may also include means for adjusting the positions of the dies horizontally in two mutually perpendicular directions to register the upper dies accurately with the lower ones.

The invention will now be further described by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is an elevation of a part of the slide and bed of a press, partly sectioned on a plane containing the axes of the dies;

FIGURE 2 is a partly sectioned elevation of the slide looking from the left in FIGURE 1;

FIGURE 3 is an inverted plan View of the slide carrying the upper dies; and

FIGURE 4 is a section on the line 44 in FIGURE 1, with the lower dies omitted.

The arrangement illustrated in the drawings employs only two pairs of dies and so it is sufiicient for the rocking movement provided by the invention to be about an axis, rather than about a point. Referring first to FIGURES 1 and 2, a slide member 1 is dovetailed to the vertically reciprocating slide (not shown) of the press. Its underside 2 is of part-cylindrical shape, the axis of curvature of the surface being in the plane of contact of the pairs of dies and perpendicular to a plane containing the axes of the two dies, midway between those two axes.

A carrier in the form of a block 3 having an upper convex part-cylindrical surface mating with the concave surface of the member 1 is secured against the underside of that member by a pair of set-screws 4 each of which is screwed into the member 1 whilst its head is received in a counterbore in the block 3, and there is a helical coil compression spring 5 under the head of each screw. The screws 4 thus hold the block 3 against the member 1 but allow a limited rocking movement about the axis of the mating curved surfaces.

A slide 6 has a dovetail engagement with the block 3 allowing relative horizontal adjustment of the slide on the block. The adjusting movement is effected by a screw 7 carried in a bracket 8 (FIGURE 2) on the slide 6. Screws 9 pressing on gibs 10 allow the adjustment to be clamped, and by loosening the screws on one side whilst tightening those on the other one can also adjust the slide horizontally in a direction perpendicular to the direction of the dovetail surfaces.

In the underside of the slide 6 there are formed two recesses with part-spherical seats 11 receiving the backing members 12 of the two upper dies 13. In practice the seats 11 are formed in separate inserts 6a in the slide 6 rather than in the material of the slide itself. The centre of curvature of each part-spherical seat 11 coincides with the centre of the face of the associated die.

Each die 13 is clamped in place in the slide 6 by three dogs 14 spaced apart and held against the slide by screws 15. The dogs are so arranged that the clamping thrust of each is radial with respect to the spherical seat allowing adjustment of the tilt of the die 13 in the slide 6 by appropriate adjustment of the three screws. FIGURE 3 shows how the adjacent dogs of the two dies are cut away to clear each other, allowing the sets of dies to be mounted with their axes as close together as possible.

The bottom dies, shown at 16, are mounted non-adjustably on the bed member of the press. Therefore all alignment of the pairs of dies is made, in the particular embodiment shown, by adjustment of the upper dies 13. To facilitate the setting up of the dies there is a location plate which has been omitted from FIGURE 1 for clarity but is shown at 17 in FIGURE 2 and in the right-hand half of FIGURE 3. This is located with respect to the slide 6 by dowel pins 18 (FIGURE 2) and held by screws 19, and it has apertures which just fit the ends of the upper dies 13 and hold them at exactly the correct relative spacing. It is used as a jig during setting up and then removed.

The lower dies are capable of vertical movement by means not shown, for ejection of the coins after striking, but are accurately located laterally by collars 20 fitting around them.

It will be appreciated that any variation in the depth of the impression produced between one side of the blank and the other can be corrected by tilting the die 13 in its spherical seat 11. Likewise any lack of concentricity between the impressions on the upper and lower faces of the blank is corrected by horizontal adjustment of the slide 6 with respect to the block 3.

Hitherto it has been difiicult or impossible to make coining presses with more than one pair of dies. However, by the provision of the curved surface 2 we allow slight tilting of the slide 6 (together with the block 3) about a horizontal axis midway between the faces of the 3 two pairs of dies. Consequently the dies are self-aligning and equal blows areproduced on the two blanks at each stroke, even though the blank in one pair of dies may be very slightly thicker than that in the other pair.

Although only two pairs of dies are shown in the embodiment described, it would be possible within the scope of the invention to use three pairs, and the surface 2 would then be part-spherical instead of part-cylindrical, with its centre of curvature at the centre of an equilateral triangle formed by the axes of the three pairs of dies.

, Furthermore it would be possible to mount the lower dies rather than the upper ones in the manner according to the invention.

We claim:

1. A multiple die coining press comprising a slide member reciprocable linearly towards and away from a bed member, a carrier mounted on said slide member, mutually opposed engaging surfaceson said slide member and said carrier, said surfaces having an arcuate cross-section,

' Imeans acting between said slide member and said carrier resiliently urging said surfaces into mutual contact, a plurality of coining dies mounted on said carrier with die faces arranged substantially in a common plane and sym metrically about a point in said plane, said point determining the centre of curvature of said arcuate cross-section, a plurality of dies mounted on said bed member and disposed to mate with said slide member, means for individually adjusting each die of one of said pluralities to enable tiltable adjustment of the face of each relative to the face of itsmating die, and clamping means for securrelative to its mating die.

2. A multiple die coining press as set forth in claim 1 wherein the adjustable dies are mounted on said carrier, a part-spherical seating surface associated with each of the adjustable mounted dies, a complementary shaped seating surface in said carrier for receiving each of said die seating surfaces, the common center of curvature of seatingsurfaces of each die being at the center of the die a0 ing each adjustably mounted die in its adjusted position A face, said clamping means fixedly engaging said seating surfaces in mutual contact.

3. A multiple die coining press comprising a slide member reciprocable linearly towards and away from a bed member, a carrier mounted on said slide member, mutually opposed, engaging, part cylindrical surfaces on said slide member and said carrier, means acting between said carrierand said slide member resiliently urging said surfaces into mutual Contact, a pair of coining dies'mounted on said carrier-with die faces arranged substantially in a common plane,'an'axis of'curvature of said part-cylindrical'surfaces lying in said plane and bisecting at right angles the line joining the centres of said die faces, a second pair of dies mounted on said bed member and disposed to mate with said carrier-mounted dies on movement of said slide member, means for individually adjusting each of one pair of dies to enable tiltable adjustment of the face of each, with respect to the face of its mating die, and clamping means for securing each adjustably mounted die in a desired disposition relative to its mating die.

4. A multiple die coining press as set forth in claim 3 wherein said adjustable pair of dies are mounted 'on the carriena part-spherical seating surface associated with each of said adjustable dies, a complementaryshaped seating surface in said carrier for receivi ng each of said die seating surfaces, the common centre of curvature of said seating surfaces of each die being at the centre-of the die face, said clamping means fixedly engaging said seating surfaces in mutual contact.

References Cited by the Examiner UNITED STATES PATENTS 21,473 9/58 Storm '101 4 3,063,664 11/62; Kahlen 101-28 FOREIGN PATENTS 525,628 5/31 Germany.

WILLIAM B. PENN, Primary Examiner.

Claims (1)

1. A MULTIPLE DIE COINING PRESS COMPRISING A SLIDE MEMBER RECIPROCABLE LINEARLY TOWARDS AND AWAY FROM A BED MEMBER, A CARRIER MOUNTED ON SAID SLIDE MEMBER, MUTUALLY OPPOSED ENGAGING SURFACES ON SAID SLIDE MEMBER AND SAID CARRIER, SAID SURFACES HAVING AN ARCUATE CROSS-SECTION, MEANS ACTING BETWEEN SAID SLIDE MEMBER AND SAID CARRIER RESILIENTLY URGING SAID SURFACES INTO MUTUAL CONTACT, A PLURALITY OF COINING DIES MOUNTED ON SAID CARRIER WITH DIE FACES ARRANGED SUBSTANTIALLY IN A COMMON PLANE AND SYMMETRICALLY ABOUT A POINT IN SAID PLANE, SAID POINT DETERMINING THE CENTRE OF CURVATURE OF SAID ARCUATE CROSS-SECTION, A PLURALITY OF DIES MOUNTED ON SAID BED MEMBER AND DISPOSED TO MATE WITH SAID SLIDE MEMBER, MEANS FOR INDIVIDUALLY ADJUSTING EACH DIE OF ONE OF SAID PLURALITIES TO ANABLE TILTABLE ADJUSTMENT OF THE FACE OF EACH RELATIVE TO THE FACE OF ITS MATING DIE, AND CLAMPING MEANS FOR SECUR-

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