Patent Application
20060021526
The invention concerns an apparatus for punching, stamping and/or shaping flat elements comprising a base body with a table and a support for the flat element, and a base plate which supports a tool punch and which to carry out the working process can be moved by means of a drive towards the support into a working station for engagement of the tool punch with the support and away from the support.
Such apparatuses are used to punch or shape flat semi-manufactured articles such as for example plates, strips and blanks, in a continuous process. Those webs, strips, plates or blanks which are referred to as flat elements can comprise different materials, for example cardboard, lined cardboard material, multi-layer material or metal plate.
Previously known apparatuses similar to the kind set forth in the opening part of this specification are provided with a direct hydraulic or pneumatic drive having a cylinder which acts on the punching tool. The full punching force has to be applied in the punching direction, whereby a jerky or shock force situation occurs and only low cycle speeds are achieved because the retraction of the cylinder has the effect of lost time.
Other known solutions operate with a pneumatic cylinder as the drive and an integrated linear guide means, whereby, besides the disadvantages indicated, in terms of mass production, there is the further disadvantage of a shorter service life. In practice faults were in part already found to occur after 40 hours. For those reasons punching tools used hitherto act as brakes on the machines.
There are also known apparatuses with a rotating punching tool, the axis of which is parallel to the strip to be processed, in that respect transversely with respect to the direction of travel. It is also possible with those known apparatuses to effect punching without stopping the strip. During the punching operation however the speed of rotation of the punching tool and the speed of the strip to be worked must be absolutely synchronised. Such solutions are hitherto only known in configurations in which the level of precision of punching, which is required for many uses, is not achieved. In that respect there are both problems in maintaining precise positional co-ordinates of a hole and also maintaining the diameter or profile tolerances and the tolerances for implementing a cut at a right angle from above downwardly, that is to say, concerning the wall of the hole.
Therefore the object of the invention is to provide an apparatus of the kind set forth in the opening part of this specification, with which a large number of very short, highly precise punching strokes can be effected in succession for producing punched holes or stampings. The invention seeks to provide in particular when dealing with fast-moving flat elements that in that respect short stoppage times and thus short cycle times and indeed working strokes which are as short as possible are achieved.
In accordance with the invention, that object is attained in that coupled between the drive and the base plate are transmission means which move the base plate from a rest position in which the tool punch is out of engagement with the support, substantially without a pressure build-up, to shortly before the working position, and then move it into the working position over a short distance while producing a high pressure between the base plate and the flat element and upon further activity of the drive move the base plate into the rest position again over regions substantially without a pressure build-up. The apparatus according to the invention can be used to punch holes and/or apply stampings in flat semi-manufactured products. The flat semi-manufactured products are here referred to generally as flat elements.
The novel apparatus can be used in particular in a continuous process to punch holes economically into those flat materials and in that respect with a very high degree of precision or to effect similarly economical and precise stampings in such materials. In accordance with the invention, in contrast to the state of the art, very short stoppage times, and a short working procedure with a short stroke movement are implemented, so that reference is made to very short cycle times.
The invention relies on the basic idea that the tool punch which is mounted on the base plate is to be driven in accordance with a given pattern of motion. This involves the motion ultimately of the tool punch towards and away from the support which holds the flat element. In the case of punching a hole can be provided in the support so that the tool punch punches through the flat element into that hole in the support. Similar considerations apply in regard to stamping. In accordance with the invention the pattern of motions itself should follow the principle of moving the tool punch (and therewith the base plate) towards and away from the working position without a substantial build-up of pressure, a greater speed of movement being provided here. When in contrast the tool punch passes into the working position, then the movement should take place only over a short distance, but in return producing a high pressure. That pattern of movements is achieved by way of an interposed transmission means between the drive and the base plate. The tool punch is advantageously always held absolutely parallel to the plane of the flat element over the entire cutting depth or stamping depth, in that working procedure.
In accordance with the invention that advantageously provides a flat, gentle, sliding and non-jerky development of forces. The invention makes it possible to avoid those impacts and jerks which occur with conventional apparatuses when the full punching force is applied in a linear direction.
In the one embodiment it is provided in accordance with the invention that the axis of the drive is perpendicular to the axis of the tool punch; whereas in another embodiment the axis of the drive is parallel to the axis of the tool punch. It is possible to envisage various design configurations for each of those two embodiments. Thus for example the drive can be a pressure-producing means with a cylinder and a piston, the piston movement of which, in one embodiment, is parallel to the direction of conveying movement of the flat element. As the axis of the tool punch is arranged perpendicularly to the plane of the flat element, the drive axis is then perpendicular to the axis of the tool punch. Among the numerous other embodiments, it is also possible to envisage a configuration in which the drive is a motor, the axis of rotation of which is parallel to that of the tool punch; in a specific embodiment, the axes even coincide. When using the basic idea according to the invention, the man skilled in the art will select the appropriate structure, depending on the respective advantages thereby presented to him.
If consideration is given to an embodiment of that above-mentioned solution, in which the axis of the drive is parallel to the axis of the tool punch, it can then be provided in accordance with the invention that the transmission means have at least one rotary lever pivotable about a stationary pivot point. Such a structure is robust and precise.
Another preferred embodiment in which the axis of the drive is parallel to the axis of the tool punch is characterised in that the linear direction of movement of the base plate is predetermined by a column guide means operative between the base body and the base plate and that the drive has a drive means which oscillates linearly in its axis (of the drive) which is perpendicular thereto. Such an oscillating drive means can be for example a pneumatic or hydraulic cylinder with a reciprocating piston. The piston rod can be viewed as such a linear, oscillating drive means, through which the axis of the drive can be imagined as being placed. The axis of the tool punch then again extends perpendicularly thereto. The column guide means permits precise angular guidance and exact working, for example punching or stamping.
In accordance with the invention a further development of such an embodiment provides that a long rotary lever is pivotable about a pivot point fixed to the base body and is coupled at its one end by way of an elbow lever pivot to one end of a short pivot lever whose other end is coupled to the base plate by way of an elbow lever mounting. That mechanical structure provides a dead center point in a given position of the long rotary lever and the short pivot lever, and as a result, having regard to the above-indicated basic idea of the invention, that arrangement affords very great force effects in the proximity of that dead center point. Inter alia that is achieved by the long travel of the linearly oscillating drive means, with the advantage of a short travel in respect of the working tool, for example the tool punch. In that respect the drive can have a pneumatic cylinder or a hydraulic cylinder. The long rotary lever, coupled to the short pivot lever (elbow lever principle) can be considered as a kinematic system which acts in such a way that the base plate provides for the implementation of a respective working operation, for example a punching operation, both in the direction of rotation of the long rotary lever in the counter-clockwise direction and also in the direction of rotation in the clockwise direction. The principle according to the invention can be clearly implemented here, more specifically, that firstly, with a large fast stroke movement and a low level of force, the tool punch is moved to a position close to the flat element and then, with a short travel distance and a high force, the working operation is carried out; whereupon, once again with a large fast stroke movement and a low level of force, the tool punch is removed from or moved away from the flat element.
In a further advantageous configuration of the invention mounted rotatably to the base plate is at least one roller which is guided in such a way as to run against at least one cam which at at least one location has a configuration with a component in parallel relationship with the axis of the tool punch. If the cam did not have any location with such a component in parallel relationship with the axis of the tool punch, then the roller which runs against the cam, upon the movement of the cam, relative to the roller, could not move either the roller or the base plate connected thereto. If, to carry out the principle according to the invention, a short vigorous stroke movement in the direction of the axis of the tool punch is desired, then the above-mentioned component of movement should be in parallel relationship with the axis of the tool at the location in question of the cam. As it is possible to produce any desired cam, it is readily possible for the roller with the base plate to be guided at any desired moment with a high force over a short travel distance in order precisely to achieve the desired working effect. The above-mentioned cam can be provided on an oscillating or rotating part of the machine, which is stationary or movable, insofar as only a relative movement is possible between the roller and the cam.
It is further desirable in accordance with the invention if the cam is provided at the periphery of a rotatably driven cylinder as the transmission means. The cam can be incorporated in the form of a groove in such a cylinder which can be rotated in a controlled fashion. Other axial raised portions on the cylinder however are also possible. At any event, mounted rotatably to a holder of the base plate are rollers which run against such a cam, for example in a groove at the periphery of the rotatable cylinder, in such a way that, depending on the respective configuration of the cam, the base plate can be moved oscillatingly by way of the holder in the direction of the axis of the cylinder which is then for example disposed in the direction of the axis of the tool punch. In that respect, in a preferred embodiment of the invention, the cylinder can also be provided with a coaxially fixed pinion which is driven by meshing engagement with an oscillatingly movable rack.
Another embodiment is characterised in that the cam is provided on the rotary lever.
Another advantageous configuration of the invention provides, similarly to the case with the rack, that the movement of the roller is along a rectilinear cam bar, namely in such a way that, in accordance with the invention, the cam is arranged on an oscillatingly movable, rectilinear cam bar.
The drive either of the above-mentioned cylinder with the groove or the above-mentioned pinion can be for example a rotary motor, preferably a servo motor. Along a full periphery of the cylinder or along the rack, the cam can have a plurality of the above-mentioned particular locations with the configuration having a component parallel to the axis of the tool punch, so that, in one revolution, the tool punch comes into engagement at least once with the support and the flat element, for example to punch it or stamp it, and possibly even between twice and four times per overall length or per full revolution.
A further advantageous configuration of the invention is characterised in that the axis of the rotary lever extends perpendicularly to the axis of the tool punch which is movable by way of the base plate in a translatory and rotational fashion relative to the rotary lever. In this embodiment the rotary lever is a carrier for the tool punch, possibly also the carrier for two tool punches. The axis of that rotary lever is parallel to the plane of the flat element which is to be worked. In this embodiment, the levers and/or the cam disks form a kinematic system and always hold the tool punch over the entire stroke movement of the punch, that is to say when moving towards the support and also upon retraction therefrom, in absolutely parallel relationship with the flat element. In this embodiment it is desirable for a counterpart tool of a similar structure to be arranged under the flat element or on the opposite side. In the case of this counterpart tool, the rotary lever, the tool carrier, also holds the tool punch in absolutely parallel relationship with the flat element. After the tool punch is lifted off the flat element the rotary speed of the rotary lever can be so established by control of the drive motor that the tool punch comes into engagement again only when the correct distance has been covered from one working location to another working location (in a stamping procedure for example from one hole to another) by a moving flat element.
The flat element can more specifically also be imagined as a moving strip of material, in which case working operations can be carried out on that strip in a continuous procedure in an economical and highly precise fashion. That is achieved with the measures according to the invention by virtue of the very short stoppage times and the equally short working process with a short stroke movement. The new apparatus permits extremely short cycle times and also makes it possible to work with strips or webs as flat semi-manufactured products in a continuous process. That also applies in regard to strips and webs which move at very high speed.
Longer service lives are achieved with the apparatus according to the invention for those fast-moving webs because only one single forward or reverse stroke movement of the base plate is required for each working operation. In addition higher cycle speeds are achieved, in particular because for example in the case of the embodiment with the long rotary lever and the short pivot lever with the drive, whose axis is perpendicular to that of the tool punch, both the forward stroke movement and also the return stroke movement are used for a respective working operation. With the embodiment which has the servo motor as the drive, the advantageously high cycle speed is achieved because a respective revolution of the servo motor can be converted into one and preferably even a plurality of punching cycles.
With all the above-specified advantages, the invention also surprisingly affords a high level of precision in regard to accuracy of the positional co-ordinates, the hole profile tolerances and the hole wall tolerances in the case of punching (and similarly when stamping or shaping).
Further advantages, features and possible uses of the present invention will be apparent from the description hereinafter of preferred embodiments, with reference to the accompanying drawings in which:
The embodiments of the apparatus according to the invention, which are illustrated in the drawings, are described and illustrated for the sake of better understanding of the invention by reference to a punching operation as the working procedure. In this case a strip of metal which is guided with a straight translatory movement on a support is selected and described, as constituting the flat element. That does not express limitation of the invention to this type of flat element to be worked.
The first embodiment of the invention, here an apparatus for punching a metal strip which is passing through the apparatus horizontally, is shown in
At its end of the long rotary lever 9, which is opposite to the upper mounting 10, the long rotary lever 9 has an elbow lever joint 13 to which a short pivot lever 14 is pivotably connected. The short pivot lever 14 is rotatably connected by way of its lower elbow lever mounting 15 provided at the other end of the pivot lever 14, to a holder 16 which is mounted fixedly to a base plate 17.
The main plane of that base plate 17 is disposed horizontally and is therefore at a spacing from and parallel to a table 18 which is also fixed to the base body 1. While however the latter is stationary, the base plate 17 can be moved with a translatory movement upwardly in the upward direction 19 or the downward direction 20. That movement is implemented by the drive having the pneumatic cylinder 4 and the piston rod 5. So that the base plate 17 remains parallel to the horizontal plane of the table, there is provided a column guide means 21 whose structure is clearly visible from
Fixed on the table 18 is a plate-like support 26, in which there is centrally disposed a hole 27 having ground upper edges 28, the dimension of which is precisely matched to the outside edge of the tool punch 24 in per se known manner. The metal strip 29 is only diagrammatically indicated above the support 26, the strip 29 being disposed between the support 26 and the tool punch 24.
In the second embodiment shown in
Upon initial extension of the piston 5, in this second embodiment, similarly to
Similarly to
The left-hand illustration in
To produce the rotary movement of the cam cylinder 35 in the peripheral direction 37, the axis of the drive which is not shown in greater detail in
The configuration of the cam 31 (and also 31′) is so selected that the tool punch 24 can be moved very rapidly towards the metal strip 29 by the steep location A with a directional component in parallel relationship with the axis 25 of the tool punch 24. At the apex of that location A the cam 31 (or 31′) becomes progressively flatter, similarly to an inclined plane, so that, with a short punching travel movement in the downward direction 20, it is possible to act with a high force on the material, for example the metal strip 29. It will be appreciated that, in this embodiment like also in the other embodiments, the flat element, here the metal strip 29, can either be stationary or it can be moved at an intermittent speed on the support 26 past the tool punch 24. In the working position even a moved strip is stopped and started moving again after the working operation.
The drive for the cam bar in the direction of the double-headed arrow 42 can again be afforded by different motors, cylinders and the like.
Finally,
The upper rotary lever 9 is rotatable about an axis 45 which is also horizontal and which extends perpendicularly to the conveying direction 44 of the metal strip 29. In the plan view in
The direction of rotation of the rotary lever 9 is indicated by the two curved arrows 49 so that it can be easily imagined that the left-hand roller 33 on the double-armed lever 46 is the roller which is the leading roller in the direction of travel and is the first one to pass into the stationary control cam when the rotary lever 9 moves from an inclined position, before it has reached the position shown in
Once again the tool punch in that way moves at a high rotary speed over a long travel distance into the position shown in
Also arranged on the side in opposite relationship to the upper rotary lever 9 is such a rotary lever which is rotatable about an axis corresponding to the axis 45. The conditions in regard to movements and control configurations are in mirror image the same as for the upper rotary lever 9 as described hereinbefore. The only difference is that the lower base plate has the above-mentioned support 26 so that the tool punch 24 can be urged linearly into the hole in the support 26 and can be retracted therefrom again linearly in the opposite direction.
As soon as the base plate 17 has been drawn out of the support (translatory movement in a direction towards the axes 45), the double-armed levers 46 leave the cams and can then be further moved without guidance.
In the embodiment illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 102 48 859.2 | Oct 2002 | DE | national |
| 103 37 864.2 | Aug 2003 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP03/11287 | 10/10/2003 | WO | 3/16/2005 |
