DE20008749U1 - Hole punch made of sheet metal - Google Patents

Description

Utility model application: “Hole punch made from sheet metal” State of the art

Portable paper punches are available in various designs and sizes. The force applied is usually transferred to the punch via a gear or a lever mechanism. This principle requires a more or less complex construction depending on the maximum filling level, which makes the device unwieldy on the one hand and results in considerable manufacturing costs on the other.

It is noticeable that in some applications only a few sheets of paper are punched. There is also a trend towards the "mobile" office, where the user carries all the equipment with them in a suitcase. Schoolchildren usually have to carry their equipment in their school bags every day. For this target group, the focus is on the lowest possible price and the highest possible value.

Merchandising companies are also always looking for products with high utility value, great advertising effect and low production costs.

Task

The task was therefore to develop a hole punch of the simplest design, designed for only a few sheets of paper (up to about 5). The device should be light, low and able to be fixed in a folder like an insert. A replacement for the usual clamping device for the documents was also desirable. The manufacturing costs should be lower than those of the simplest models to date. The product should enable lettering, colors, advertising prints, images, etc. to be applied.

Perhaps the design of the entire hole punch should be variable depending on the target group without affecting the basic function.

Solution

The solution is designed according to the characteristics of claim 1. A punched sheet metal plate is designed using a few processing steps so that all functions required for the punching process can be fulfilled. The punch and punching die are formed and ground. The necessary degree of freedom is created by weakening the sheet metal in the middle and then bending it. This simultaneously causes the spring to return. Guide tongues that make insertion easier and centering marks for central alignment of the sheets round off the functionality. Additional fixing holes allow space-saving storage in a folder if required. By moving the hole punch within the tapered fixing holes, the hole punch can be clamped and the documents underneath can be fixed.

Advantages

The completely new basic concept, which completely dispenses with additional parts, is considered to be essential. Together with only a few processing steps, this results in a very cost-effective production of the product. In addition, the device is new and variable in its appearance, light, compact and suitable as an advertising medium. It is therefore to be expected that this will open up sales markets that cannot be served with the previous designs. Due to its flat design, the hole punch itself takes up only slightly more space than a conventional clamping device, which can be replaced with this solution.

The drawings of an exemplary embodiment show in detail:

Figure 1 .a) Raw board in side view

Figure 1 .b) Raw board in top view

Figure 2.a) Punched and deep-drawn board in side view

Figure 2.b) Punched and deep-drawn board in top view

Figure 3.a) Side view of ground board

Figure 3.b) Top view of ground board

Figure 4.a) Finished hole punch with bow in side view in enlarged

Depiction

Figure 4.b) Finished hole punch with bow in top view

Figure 5.a) Hole punch fixed in the folder in side view

Figure 5.b) Hole punch fixed in the folder in top view

Explanations of how it works

A blank A is made from a thin sheet, which is shown as an example in Figure 1.a) and b). The thickness d of the blank is determined by manufacturing and functional requirements. The outer contour should be designed in such a way that it meets the requirements described below.

and can thus take on functions. Forms that deviate from this should at least be based on the basic geometry shown in order to enable filing in folders. The choice of material depends on the requirements for machining and forming, corrosion resistance and the modulus of elasticity.

According to Figure 2.a) and b), the circuit board is processed as follows using suitable deep-drawing, punching and/or other tools:

Two cups B with an outer diameter 0 _as = desired hole diameter and two cups C with an outer diameter 0 _am ~ 0 _as + 2 x d later produce the punches M and hole matrices N required for the later function.

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» * · • • * · · • * ·»

The exact choice of diameter depends on manufacturing and functional conditions.

Weakenings D are punched out of the plate A along the future bend and symmetry line I. This creates webs R, the width of which, depending on the material selected, must be adjusted to the later function as a return spring and quasi-joint. Two stops E and two centering marks F are integrated into this weakening(s) D.

Four guide tongues G are assigned to the later punches B and hole matrices C in such a way that they point towards each other, but do not coincide with the line of symmetry I when the board A is later bent.

Two elongated, tapered fixing holes S later provide fastening and clamping options in file folders.

This should be followed by a procedure to deburr the half-finished board A.

Machining, preferably grinding of the surfaces H of the cups B and C as shown in Figure 3.a) and b), gives the punches M and hole matrices N their final shape and necessary sharpness.

As shown in Figure 4.a) and b), the plate is finally bent so that the punch M (resulting from cup B) and the hole die N (resulting from cup C) lie exactly on top of each other. Care must be taken to ensure that the now finished hole punch L leaves a gap s between the opening for the paper sheets K to be punched. The spring bars R, which are designed accordingly in terms of their width, cause the hole punch to reset after it has been activated and at the same time allow an actuation angle α required for the punching process.

The stops E are then bent so that they represent a vertical limit within the punch L for the sheets K to be punched. The bending radius r and the distance a of the hole locations to the stops E must be selected in this design so that when the punches M pass through the hole plane they enter the hole dies N as vertically as possible (ß = 0). An inevitable inclination of the cutting edges (ß > 0) at the beginning of the shearing process also has a positive effect on the cutting process.

The hole process now looks like this:

When inserting the sheets K to be punched, the material is guided between the punch M and the punching die N using the guide tongues G. The stops E enable the correct distance a of the punching points to be set from the edge of the material. The sheets K, which have previously been marked in the middle, can then be punched through the

Centering marks F are precisely aligned. Because the centering marks F are arranged on both sides, it is irrelevant which leg P, Q of the hole punch L is facing the operator. The actual punching process is then carried out by manually pressing the legs P and Q together. The punches M transport the resulting blanks O out of the hole dies N.

If necessary, the hole punch L itself can be filed using the binder clips T of a folder thanks to the fixing holes S, as shown in Figure 5.a) and b). By moving the hole punch L in the direction U within the fixing holes S, the hole punch L can be clamped in a force-fitting manner and documents lying underneath can be held in place.

List of reference symbols Sheet metal plate »* ·*
• ·» *
· · * A Cups for stamps ·* · · » ·
* ··· · · ·♦· , B Cups for hole matrix • « · · · * C weakening D attack E Centering mark F Guide tongue G Machined surfaces H Symmetry line I arc K Finished hole punch L Rubber stamp M Hole matrix N Round O Lower punch leg P Upper punch leg Q Spring bars R Fixing holes S Stapler T Direction when clamping U

Claims (9)

1. Hole punch with at least one stamp and at least one hole die for perforating sheet material, characterized in that stamp M and hole die N are made from a single base body. 2. Hole punch according to claim 1, characterized in that the base body is designed as a sheet metal plate A which is bent along a line of symmetry I with respect to the punch M and hole die N such that the two bent legs P, Q are movable relative to one another, the centers of the respective punches M and hole dies N assigned to one another being arranged at the same distance from the line of symmetry I on the sheet metal plate A. 3. Hole punch according to claim 1 or 2, characterized in that the punch M and hole die N consist of deep-drawn and subsequently machined cups M, N. 4. Hole punch according to claim 1, 2 or 3, characterized in that webs R remain along the line of symmetry I as a result of weakenings D, which on the finished hole punch both cause a resilient return of the legs P and Q of the hole punch and enable an actuation angle α necessary for the punching process. 5. Hole punch according to claim 1, 2, 3 or 4, characterized in that stops E punched out of the sheet metal plate A and correspondingly bent determine a defined distance a of the hole locations to the material edge. 6. Hole punch according to claim 1, 2, 3, 4 or 5, characterized in that guide tongues G worked into the sheet metal plate A, which are each assigned to the punches M or hole matrices N, enable the sheets K to be punched to be guided into the hole gap s. 7. Hole punch according to claim 1, 2, 3, 4, 5 or 6, characterized in that centering marks F worked into the sheet metal plate A enable central alignment of the sheets K to be punched by the hole punch. 8. Hole punch according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that fixing holes S worked into the sheet metal plate A enable a space-saving fixing of the hole punch in binders. 9. Hole punch according to claim 1, 2, 3, 4, 5, 6, 7 or 8, characterized in that the tapered fixing holes S worked out in the plate A enable the hole punch to be clamped with binding brackets T and thus to hold the documents underneath in the folder.