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(11) | EP 0 130 955 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Advancing press tool |
| (57) Press tool provided with two mutually opposing, registering and relatively movable
column (2) mounted carriers (1,3) for tool parts (6, 7) for working an elongate workpiece
(21), a device (9,11-19) mounted on the first (1) of the carriers for advancing the
workpiece through the tool formed by the tool parts and means (22) mounted on the
second carrier for actuating the advancing device. The advancing device includes a
slide (9) displaceably mounted on the first carrier (1) and a gripping element (15)
mounted on the slide, said element being actuable by means (22) mounted on the second
carrier (3) for clamping or releasing the workpiece (21) to, or from the slide, and
also for displacing the slide a predetermined distance through the tool parts (6,
7). Figure 1 is a suitable illustration. |
Technical Field
[0001] The present invention relates to a press tool provided with two mutually opposing, registering and relatively movable column-mounted carriers for tool parts for working an elongate workpiece, a device mounted on the first of the carriers for advancing the workpiece through the tool formed by the tool parts and means mounted on the second carrier for actuating the advancing device.
Background Art
[0002] Press tools of the kind described above and advancing means which can be used in conjunction therewith are already known, e.g. from the Swedish Patents Nos. 152 989 and 188 533, the US Patents Nos. 1 434 192, 1 968 479 and 2 342 049, the British Patent No. 626 689 and the German Patent No. 621 052.
[0003] In the cases where the known press tools include an integrated advancing means, which involves considerable advantages, such as greater exactness in advancing stroke, less material waste, better utilization of available space and greater operational reliability, such press tools do not form units which can optionally be used in practically any kind of press at all and which can be easily changed and moved to another press when required. Furthermore, these press tools have a complicated structure with a large number of parts, resulting in that tolerances of the finished workpiece cannot be kept (particularly after the tool has been used for some time) and that costs for the manufacture of the tool are high.
Disclosure of Invention
[0004] One object of the present invention is to at least partially remove the disadvantages with already known tools and to provide a press tool with integrated material advance, which can be made as a unit and without having to be dismantled can be used in practically any kind of press at all, and which comprises a small number of parts of simple embodiment, partly to cheapen the tool, and partly to ensure that an expensive workpiece, such as a gold or silver strip can be worked without unnecessary waste of material and with maintenance of predetermined tolerances.
[0005] This object is achieved by the press tool in accordance with the invention having been given the characterizing features disclosed in the claims.
Description of Figures
[0006]
Figure 1 is a partially cut-away side view of a press tool in accordance with the invention in a first position,
Figure 2 is a view, seen from the right and partially cut away, of essential portions of the tool according to Figure 1,
Figure 3 is a partially cut-away side view of the tool illustrated in Figures 1 and 2 in a second position.
Preferred Embodiment
[0007] The press tool illustrated in the Figures comprises a lower plate 1 and two upstanding columns 2, and an upper plate 3 with downwardly directed sleeves 4 received in holes 5 made in the plate 3. The upper plate 3 is guided for registering movement relative the lower plate 1 by the columns 2 received in the sleeves'4 and holes 5.
[0008] The aforementioned details,1-4 form a unit including a tool for working a strip-like workpiece as well as an advancing device for the workpiece. The plate 3 can be displaced away from the plate 1 without restriction and can be displaced towards the plate 1 against spring bias exerted between plates 1, 2, and excercised by compression springs 20, which are guidable between, and removable from, plates 1, 2. The springs also form spacers for keeping the plate 3 a predetermined distance from the plate 1 when the tool is unloaded, as illustrated in Figure 1.
[0009] The bottom plate 1 carries a first tool part, such as a die 6, and the upper plate 3 carries a second tool part such as a punch 7 including a punch holder 7a for a punch element 7c thrusting into a punch guide 7b. The guide 7b is mounted at a fixed distance from the die 6 and accommodates a compression spring 7d together with a ball 7e biased by the spring.
[0010] The lower plate 1 is provided with two guider rails 8, between them guiding a slide 9 for rectilinear reciprocatory motion in relation to the tool parts 6, 7. The slide 9 is provided with a nose 11 thrusting into a slot 10 in the plate 1, and two upstanding walls 12, in which is removably mounted a shaft 13; there being a stop pin 14 removably inserted in the upper face of each wall. A U-shaped rocker 15 (see Figure 2) is pivotably mounted on the shaft 13 between the walls 12. Relative its centre line the rocker 15 is eccentrically mounted on the shaft 13.and is upwardly provided with a shaft 16 extending outwards on either side of the U-shaped legs, each end of the shaft being provided with a roller 17 which is rotatable. Between both legs of the rocker 15 the shaft 16 forms an attachment for at least one tension spring 18, the other end of which is attached to a holder 19 on the plate 1.
[0011] The use and function of the press tool as well as .some details included in it will now be described together with a modified embodiment of the slide 9.
[0012] The press tool illustrated in the Figures is inserted as a unit in some suitable press, only the lower plate 1 being fixed to the lower press table, and this without needing to be oriented particularly accurately.
[0013] The piece on which work is to be performed, namely a gold or silver strip 21, is inserted between the die 6 and the punch guide 7b from left to right in Figure 1 until the right-hand end edge of the strip is immediately adjacent a lower engaging edge 15a of the rocker 15. The strip is retained in the inserted position by friction between the die 6 and the ball 7e biased by the spring 7d. The press is then operated, and its upper platen presses the plate 3 downwards against the bias of the springs 20. During the subsequent operation, the punch element 7c punches holes in the strip, or alternatively impresses it in some way. In conjunction with this operation, bevelled undersides of two legs dependent from the plate 3 engage against the rollers 17. At continued downward movement of the legs 22 the rollers 17 are urged to the left in Figure 1 thereby causing the rocker 15 to pivot anti-clockwise about the shaft 13 against the bias of the spring 18, the edge 15a relinquishing contact with the horizontal surface of the slide on which the strip rests. After the anti-clockwise pivoting motion of the arm 15 has ceased, by the shaft 16 engaging against the stop pins 14, continued downward movement of the legs 22 cause the slide 9, via therollers 17, shaft 16 and stop pins 14, to be displaced towards the tool parts 6, 7 until the left-hand vertical edge above the bevel on each leg 22 engages against the associated roller 17. The details of the press tool then assume the positions illustrated in Figure 3.
[0014] After terminated working and retrieving movement of the advancing device 9, 11-18 the press is opened so that the springs 20 return the plate 3 to the position illustrated in Figures 1 and 2.rDuring the beginning of this movement, the engagement of the bevels on the legs 22 against the rollers 17 cause-the rocker 15 to be pivoted clockwise about the shaft 13 by the spring 18 so that the edge 15a, suitably extending right across the width of the strip 21, clamps the strip to the slide 9. After the strip has been clamped by the edge -15a the punching element 7c releases its engagement with the strip. Continued upward movement of the plate 3 results in that the legs 22 successively leave the rollers 17, the slide 9 being moved again into the position-illustrated in Figure 1 with the aid of the spring 18. When engagement between the legs 22 and rollers 17 has ceased, the slide 9 is once again returned to the position illustrated in Figure 1, where its nose 11 engages against a stop screw 23, which is adjustable for regulating the stroke of the slide 9 (the distance "a" in Figure 3) and thereby the amount of the advance of the strip 21 through the tool parts 6, 7 to be right from the position in Figure 3.
[0015] If it is desirable to reverse the advancing movement of the strip 21 so that it takes place from right to left, instead of from left to right as described above, the shaft 13 is released from the walls of the slide 9 and from the rocker 15, the details 13, 15 then being assembled again on the slide 9 but with the rocker 15 oriented differently so that the edge 15a is to the left of the shaft 13 in Figures 1 and 3. Further to this measure, the stop pins 14 are removed and inserted in holes in the slide 9 to the right of the rocker 15. With the new orientation of the rocker 15 and with the pins 14 in their new holes, advancing of the strip 21 will take place when the plate 3 is moved downwards towards the plate 1, the edge 15a engaging against the strip and the retrieving movement occurring when the plate 3 is raised from the plate 1, the edge 15a being at a distance from the strip determined by the horizontal distance of the shaft 13 from, and to the left of, the pin 14, which engages the shaft 16 to limit its movement to the right. Reversal of the advancing direction so that it takes place from right to left in Figures 1 and 3 is particularly advantageous if the strip 21 is given projecting portions by the tool parts 6, 7 which make difficult the passage of the strip through, and its engagement with the advancing device 9, 11-19.
1. Press tool provided with two mutually opposing, registering and relatively movable
column (2) mounted carriers (1, 3) for tool parts (6, 7) for working an elongate workpiece
(21), a device (9, 11-19) mounted on the first (1) of the carriers for advancing the
workpiece through the tool formed by the tool parts, and at least one means (22) mounted
on the second carrier (3) for actuating the advancing device, which includes a displaceably
mounted slide (9) on the first carrier (1), with an gripping element (15) mounted
on the slide, characterized in that said means (22)mounted on the second carrier (3)
is adapted to actuate the gripping element (15) such that the latter clamps or re-
.leases the workpiece (21) to, or from, the slide and also displaces the slide a predetermined
distance in relation to the tool consisting of tool parts (6, 7).
2. Press tool as claimed in claim 1, characterized in that during a first part of
the actuation by said means (22) of the gripping element (15) the slide (9) remains
inactive, and that during a second part of said actuation the engaging element actuates
the slide for displacement relative the tool parts (6, 7).
3. Press tool as claimed in claim 1 or 2, characterized in that the gripping element
(15) is pivotable and preferable eccentrically mounted on the slide (9) and is spring
(18) biased in a direction towards the means (22) mounted on the second carrier (3).'.
4. Press tool as claimed in claim 1, 2 or 3, characterized by at least one roller
(17) rotatably mounted on the gripping element (15) for engagement with a sloping
surface on said means (22).
5. Press tool as claimed in any of the preceding claims, characterized in that the
gripping element (15) is removably attached to the slide (9) and assemblable on it
in either of two positions, the one resulting in release by the element of the workpiece
(21) and the other resulting in clamping the workpiece when the gripping element is
actuated by said means (22).
6. Press tool as claimed in any of the preceding claims, characterized by at least
one stop means (14) removably attached to the slide (9) which can be fitted to the
slide in either of two positions, the one resulting in actuation of the gripping element
(15) and displacement of the slide via the stop means in a direction towards the tool
parts (6, 7) while the gripping element is released from the workpiece, and the other
resulting in the actuation of the gripping element and displacement of the slide via
the stop means in a direction away from the tool parts while the gripping element
is released from the workpiece.
7. Press tool as claimed in any of the preceding claims, characterized by springs
(20) acting between both carrier plates (1, 3) for displacing said plates away from
each other.