CH659970A5 - METHOD AND DEVICE FOR AUTOMATICALLY CUTTING, ACCORDING TO A SELECTED DRAWING, A SHEET ADHERING DETACHABLE TO A SUPPORT. - Google Patents

Description

The present invention aims to provide users with a simple and inexpensive means for automatically cutting, under the control of a programmable table calculator for example, according to a chosen design, a sheet adhering to a support.

The present invention comprises a method according to claim 1, and a device for carrying out this method, which is according to claim 2.

The appended drawing illustrates, by way of example, an embodiment of the method according to the invention and also represents, by way of example, an embodiment of the device according to the invention for the implementation of this process.

Fig. 1 shows an overall side view of this embodiment of the device.

Fig. 2 is an axial sectional view of the device according to FIG. 1.

Fig. 3 is a cross section along 3-3 of FIG. 2.

Fig. 4 is a sectional view, on a larger scale, of a part of the device during the cutting work.

The apparatus or device shown comprises an outer body 1, made of plastic, and an inner body 2, metallic, of generally cylindrical shape and axially pierced with a hole 3 which ends in 4 with a conical flare 4, at the location of the end 5 of the body 2.

In the hole 3 is arranged a clamp comprising a cylindrical part 6 capable of sliding axially in the hole 3, and a slotted part to form four arms 7 (fig. 3) which, at their free end, have a conical part 8 provided for cooperate, as will be seen below, with the cone 4 of the body 2.

The cylindrical part 6 of the clamp 6, 7 is internally and axially threaded, as seen in 8. An axial screw 9 cooperates with the thread 8. This screw extends a cylindrical rod 10 rotating with gentle friction in an axial hole 11 of the body 2, which opens into the hole 3. The rod 10 ends, at its end opposite to the thread 9, by a knurled button 12 serving for its actuation in rotation. At 13 is a washer inserted between this button 12 and the neighboring end of the body 2.

The interior of the split part 7 of the clamp 6, 7 forms an axial cylindrical channel 14 into which a cylindrical part 16 of a knife holder 15 can slide. A cylindrical part 17 of the knife holder 15 is located at the outside of the body 2, beyond its end 5. The diameter of the part 17 is greater than that of the part 16 and of the channel 14.

At the junction of parts 16 and 17 there is a shoulder 18 intended to abut against the free end of the arms 7 of the clamp 6, 7, in order to properly fix the axial position of the knife holder 15 in the clamp 6, 7.

The knife holder 15 has four longitudinal slots 19, in its region which is close to the free end of the arms 7 of the clamp 6, 7 (when the members are in the position shown in FIG. 2, which is the position device).

In its part 16, the knife holder 15 is axially threaded. A micrometric adjustment screw 20 is engaged in this internal thread.

The interior of the knife holder 15 forms a cylindrical housing 21 in which a special knife 22 is partially engaged. This knife comprises a cylinder 23 which, in the position shown in FIG. 2, is located opposite the slots 19. In its lower part (in FIG. 2), the knife has a cylindrical part 24, of smaller diameter than 22 and which is extended by a tapered point 25, having a shape of revolution, therefore conical with a very small angle at the top. At least the part 24.25 of the knife is made of a very hard material, such as tungsten carbide for example. The angle at the top of the cone 15 can be 30e for example.

The tip 25 is provided to protrude from the end 26 of the part 17 of the knife holder 15, by an amount which can be adjusted with precision as will be seen.

The operation of the apparatus described is as follows.

We begin by adjusting exactly the amount by which the tip of the cone 25 projects beyond the end 26 of the knife holder. For this, the head 12 is turned so as to move the clamp 6, 7 towards

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the bottom in fig. 1 and to separate the conical end of the arms 7 from the cone 4. Consequently, the knife holder 15 can be pulled out (downwards in FIG. 1) from the pliers 6, 7. Next, the upper end of the knife 22 being kept in contact with the end of the adjusting screw 20, it is acted on the latter to cause the tip of the cone 25 to exceed the end 26 by a well-defined quantity, which is for example three-quarters equal of the thickness of the sheet 27 to be cut (fig. 2 and 4). This sheet can have a thickness of 0.05 to 0.10 mm for example and be in "Rubilith".

This done, the knife holder 15 is reintroduced into the pliers 6, 7 taking care that the shoulder 18 abuts against the end of the arms 7. Then, the knob 12 is turned to bring the conical end of the arms 7 of the pliers in contact with the cone 4 and tightened by turning. The arms 7 then flex and act radially on the slotted part of the knife holder 15, which in turn flexes and energetically clamps the part 22 of the knife, which immobilizes the latter in the knife holder 6, 7 and the latter by relative to the body 1, 2. Simultaneously, the clamp and the body of the device are secured.

The adjustment being thus completed and the body being brought into engagement with a clamp 28 of the movable member controlled 30 of a plotter (plotter) of known type, instead of the usual pen of this plotter, the end of the conical part 25 of the knife in the cutting sheet 27, until the end 26 of the knife holder comes into contact with the sheet 27. The tip of the cone is then close to having passed through the sheet 27, but nevertheless at a distance from a support 29 (in “Mylar” for example) on which the sheet 27 adheres as is well known.

The work of automatically cutting sheet 27 can now begin.

A program containing the instructions for controlling the mobile pen-holder of the plotter, which corresponds to the drawing 5 of the cut to be made, being introduced into a small calculator or a small table computer, this mobile organ is controlled by this calculator or this computer. The end of the tip 25 then moves exactly as would the usual pen of the tracer and, thus, this tip produces in the material of the sheet 27 10 a groove having the shape of the cut to be made. During the entire movement of the knife, the end 26 of the device remains in contact with the sheet 27 and slides over it, thus ensuring that the tip of the cone 25 always remains at the same depth in this sheet.

Once this work is completed, the sheet 27 is detached from its sup-port 29 and the parts of this sheet foreign to the cutting are removed by tearing along the groove. Given the very small diameter of the active part of the tip 25 and the very small thickness of the part to be torn, the result is a clean cut practically equivalent to that obtained with a conventional cutting knife.

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The shape of revolution of the knife-shaped point 25 makes it possible to cut all the possible shapes without difficulty: curves, sharp angles, etc.

The use of the apparatus is not limited to the cutting of masks 25 for the preparation of microstrip circuits. It can be envisaged in all cases where it is a question of carrying out a cutting according to a design chosen from a thin sheet of non-metallic material.

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Claims (4)

659,970 1. Method for automatically cutting, according to any chosen design, a sheet detachably adhering to a support, by means of a knife movable relative to this support and controlled according to a program corresponding to the chosen design of the cutting to be produced, characterized in what is used is a knife (22) whose active part is formed by a tapered point, of revolution (25), the end of which is inserted into the thickness of the sheet to be cut (27), without it passes through it completely, after having adapted the body of this knife (1) to the movable controlled member (30) of a plotter device itself controlled by a programmable calculator, and in that which is produced in said sheet to cut a groove having the shape of the chosen design, by the controlled movement of the knife (22, 25) thus driven into the sheet to be cut (27), after which said sheet (27) is removed from its support (25) and detaches its foreign parts from the chosen design, by tearing along the said s illon. 2. Device for implementing the method according to claim 1, for automatic cutting according to any chosen drawing, of a sheet (27) detachably adhering to a support (29), characterized by a knife (22, 25 ) whose body (1,2) is designed to be adaptable to the movable member (30) pen holder of a plotter device controlled by a programmable calculator, in that the active part of this knife is a point tapered, of revolution (25), capable of projecting from a part (18) fixed to said body of this knife (1,2), in that means (20) are provided for adjusting with precision, and according to the thickness of the cutting sheet (27), the quantity of which the end of this point (25) protrudes from a part (17) which is intended to rest and slide on the surface of the cutting sheet while the point (25) of the knife, pressed into this sheet as close to said support (29) of this sheet, is moved by said movable member (30) of the plotter, to produce in this sheet a groove having the shape of the chosen design. 2 3. Device according to claim 2, characterized in that it comprises a removable knife holder (15) in which a cylindrical body (22) of the knife is slidably mounted, a micrometric screw being provided on this knife holder, for adjusting the quantity of which the point (25) of the knife protrudes out of this knife holder (15) of which a part (17) is that intended to rest and slide by its end (26) on the sheet to be cut (27) during cutting work. 4. Device according to claims 2 and 3, characterized by a clamp (6, 7) disposed in the body (1, 2) of the device and in the active part of which is mounted the knife holder (16), the latter having slots (19), the active part (7) of the pliers (6, 7) being provided to clamp said slotted part (19), to simultaneously immobilize the knife holder relative to the body (1, 2) of the appliance, and the knife (22) inside the knife holder after adjusting the position of this knife (22) in this knife holder. The making of masks for the manufacture of microstrip circuits requires very precise cutting of inactive sheets or films (such as those known under the brand "Rubilith") adhering to a support (in material such as that known under the brand "Mylar ”), Which, when this cutting is done by hand, is very tedious and unsatisfactory, since the precision obtained depends on the skill of the operator. We tried to automate this cutting work and we now use a special device, called coordinato-graph, which has a movable knife whose movement is controlled by a very powerful computer and according to a program established in each case according to the drawing that it's about cutting. However, due to the extremely high cost of the coordinator, many laboratories are unable to use this technique.