Patent Application
20110277607
The invention relates to a counterholder device for an apparatus for removing knockout parts from a workpiece sheet or the like.
Such a counterholder device is known from DE 697 01 218 T2. The known counterholder device is characterized by a tongue-like portion which projects into a cavity for a knockout part of a die, with regions of the knockout part resting on the ends of the tongue-like portions. During the knockout process, a knockout member moves vertically from top to bottom and thus comes into contact with the knockout part. In so doing, the knockout part is pressed at its edge regions against the tongue-like portions of the counterholder device. During the further downward movement of the knockout member, the tongue-like portion of the counterholder device moves downward together with the knockout member and with the interposition of the knockout part. At the same time, an elastic deformation of the tongue-like portion of the counterholder device takes place. During the further downward movement of the knockout part, the tongue-like portions are overstretched until (with the knockout part already separated out) they snap over the knockout parts and assume their original position again. It is thus ensured that, during the subsequent upward movement of the knockout member, the knockout part possibly adhering to the knockout member is stripped from the knockout member at the tongue-like portion of the counterholder device. The design and dimensioning of the known counterholder device must be designed as a function of the respective knockout part. Moreover, owing to the required flexibility or elasticity of the tongue-like portion, the counterholder device is usually produced from compression-molded material whose durability or number of cycles is limited.
Furthermore, in the 1970s, the Applicant developed the so-called “Power Stripping Dyn Stiftsystem”. Here, the die is provided with stud-like projections which serve as abutments when pressing down the knockout parts. Owing to the resistance of the stud-like projections, the necessary nonpositive engagement for a relatively reliable knockout operation results between the knockout part and the pins responsible for the downward movement of the knockout part. A disadvantage here, however, is that the stud-like protuberances on the die tend to wear as a result of the constant friction between the knockout parts and said protuberances. Consequently, it is relatively difficult to ensure the functional reliability of the knockout process over a prolonged period.
Starting from the prior art represented, the object on which the invention is based is to develop a counterholder device for an apparatus for removing knockout parts from a workpiece sheet or the like such that, together with a high process reliability, a very long service life of the counterholder device is made possible. This object is achieved in the case of a counterholder device as disclosed herein. The idea behind the invention is to reduce the wear of the counterholder device by means of rigid, tongue-like portions.
Advantageous developments of the counterholder device according to the invention are also specified herein. Falling within the scope of the invention are all combinations of at least two features disclosed in the claims, the description and/or the figures.
With particular preference, it is provided that the basic body and the tongue-like portion consist of hard material, in particular of metal. Owing to the metal design, the counterholder devices have a particularly high durability or service life and, moreover, can be handled particularly easily, for example can be fitted into the corresponding recesses of the die.
The counterholder devices can be produced particularly economically and cost-effectively if the basic body and the tongue-like portion are connected to one another in one piece and are formed as a stamped/bent part.
In an alternative embodiment, it is also possible that the basic body and the tongue-like portion are connected to one another in one piece and are formed as a cast part or milled part.
For simple fastening of the counterholder device in the die, it is provided that the basic body is accommodated in the recess with a form and force fit, and that the basic body has a conical shape. Given a correspondingly accurately produced cavity, the conical shape moreover makes possible or ensures an exact height positioning of the counterholder device in the die.
In this case, it is also particularly provided that the upper side of the basic body and of the tongue-like portion terminates at least approximately flush with the upper side of the die. This also reliably prevents a catching of parts of the blanks during their transport above the die.
Furthermore, it is particularly preferred if the tongue-like portion has a structured shape on the side facing away from the basic body. This makes it possible in an advantageous manner to ensure a high operational reliability of the apparatus.
It is particularly preferred here if the structured shape is formed as a toothing. By means of such toothings, in particular by means of fine toothings, it becomes possible to adapt the counterholder device to the respective waste contours to be knocked out.
The invention also comprises an apparatus for removing knockout parts from a workpiece or the like, having a counterholder device according to the invention. Such an apparatus has the advantage of a particularly high operational reliability and service life.
Further advantages, features and details of the invention will emerge from the following description of preferred exemplary embodiments and with reference to the drawings, in which:
Like parts or parts having the same function are provided with identical reference numbers in the figures.
The workpiece sheet 2 is in particular a cardboard or a corrugated board and the knockout part 1 is a part which is connected via webs or the like to the remaining workpiece sheet 2 and which is intended to be detached from the workpiece sheet 2 by means of the apparatus 100. Such an operation is also referred to as knocking out.
The apparatus 100 comprises a lower part 101 which is arranged in a fixed position, preferably consisting of multi-glued plywood, and an upper part 102 which is arranged movably up and down with respect to the lower part 101 and which likewise preferably consists of multi-glued plywood. Arranged on the underside of the upper part 102 is preferably a plurality of knockout elements 103 which, in the exemplary embodiment represented, are formed as bent sheet-metal parts or else as steel pins. The knockout elements 103 can in particular also be designed in accordance with EP 1 068 053 B1 of the Applicant and have, for example, additional pushing teeth for the targeted movement of the knockout part 1.
As can best be seen from
The cavity 104 is equipped with additional recesses 107 in order to accommodate counterholder devices 10 according to the invention. Moreover, like the cavity 104, the recesses 107 are produced or formed in particular by means of laser beam cutting devices. The recess 107 has a first region 108 which is approximately rectangular in plan view and which is connected to the cavity 104 via a second region 109 which is approximately trapezoidal in the exemplary embodiment. Moreover, both the cavity 104 and the recess 107 are formed over the entire height or thickness of the lower part 101.
The apparatus 100 according to
As can best be seen from
The basic body 11 is conically formed such that, when inserted or fastened in the first region 108 of the recess 107, it is securely accommodated in the recess 107 by clamping or pressing, while the upper side of the basic body 11 and of the portion 12 preferably terminates flush with the upper side of the lower part 101.
What is essential is that the counterholder devices 10, 10a or 10b consist of hard material, in particular of metal, and that the tongue-like portion 12 is rigidly formed or arranged in a direction parallel to the direction of movement of the upper part 102 of the apparatus 100.
The end portions or end regions 14 of the tongue-like portions 12 which face away from the basic body 11 preferably have a fine toothing 15. Whereas in the exemplary embodiment represented in
The particular shape of the fine toothings 15 or the dimensioning of the tongue-like portions 12 should in particular be adapted to the particular application, i.e. in particular to the shape of the knockout part 1 and the material used.
The mode of operation of the apparatus 100 in conjunction with the counterholder elements 10 according to the invention is as follows: as soon as the workpiece sheet 2 is positioned with its knockout part 1 in the region of the cavity 104 of the apparatus 100, the upper part 102 begins to move downward, and the knockout elements 103, which are arranged at a distance from the counterholder elements 10 in the direction of movement, come into operative connection with the upper side of the knockout part 1. In so doing, the knockout elements 103 press the knockout part 1 into the cavity 104, and the edge regions of the knockout part 1 come into operative connection with the tongue-like portions 12, in particular with the fine toothings 15 of the counterholder elements 10. This results in a frictional engagement between the knockout part 1, the counterholder devices 10 and the knockout elements 103.
As the knockout part 1 is pressed down further into the cavity 104, the (web-like) connections between the knockout part 1 and the workpiece sheet 2 break, with the result that the knockout part 1 is pressed into the cavity 104 with further deformation. It is essential here that the tongue-like portions 12 of the counterholder devices 10 remain at least substantially rigid at their location, i.e. are not pressed into the cavity 104. As the knockout part 1 is pressed into the cavity 104, the knockout part 1 is here deformed until its edge regions overcome the end regions 14 of the tongue-like portions 12 of the counterholder devices 10, such that the knockout part 1 passes into a waste container or the like situated below the lower part 101. During the subsequent upward movement of the upper part 102 of the apparatus 100, it is ensured by the rigid counterholder devices 10 that a knockout part 1 possibly adhering to the knockout elements 103 bears against the underside of the counterholder devices 10 and is prevented by these from making a further upward movement or is stripped from the knockout elements 103. This ensures a reliable separation of the already separated-out knockout part 1 from the knockout elements 103.
The counterholder devices 10 described so far can be adapted or modified in numerous ways without departing from the idea of the invention. In particular, the shape and the choice of the material of the counterholder device is not limited to the embodiments which have been illustrated or described. Furthermore, it can also be provided that the counterholder devices 10 have, in particular for the use for relatively large, round knockout parts 1, 1f, a receptacle on both sides, i.e. arranged opposite one another.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2010 006 741.3 | May 2010 | DE | national |
