Cutting system for dividing panels of glass or plastics quietly and cleanly using high pressure water jet, employs water-filled chamber to absorb residual energy of jet

The invention relates to a method for cutting roughly perpendicular material panels by means of a high pressure water jet, the high pressure water jet entering a water-filled chamber in the area of ​​its exit point from the material panel through an inlet opening.

The invention also relates to a device for cutting an approximately perpendicular sheet of material by means of a high pressure water jet, with a chamber connected to the water circuit and connected to the water circuit with an inlet opening for the high pressure water jet.

Such a method and such a device for carrying it out are known from US Pat. No. 5,111,652. In this case, a material plate is cut in a lying position. There is no fundamental obstacle to aligning the water-filled chamber in such a way that the material plate can be cut vertically. The disadvantage, however, is that, as long as there is no cutting, the chamber either runs empty or a constant flow of water emerges via the inlet opening. In the first case, the control system must ensure that the chamber is (again) filled with water before the high pressure water jet starts to cut, otherwise the chamber would be destroyed almost immediately from the inside by the high pressure water jet entering. In the latter case, the water emerging from the inlet opening must be collected and continuously pumped around even when the cutting device is not in use.

In such a method, the high pressure water jet is directed onto the material plate, for example a plastic or a glass plate, by means of a nozzle with a diameter of usually less than 1 mm under a pressure of 200 to 400 MPa. Abrasive particles can be mixed into the water. The nozzle arranged above the sheet of material moves along the predetermined cutting contour and for this purpose is mounted, for example, on a slide that can be displaced in two mutually orthogonal directions. The material plate rests on supports over a water-filled tub. The high-pressure water jet emerging on the underside of the material plate in the area of ​​the cut gap strikes the water surface with high residual energy, but in the area of ​​the supports of the material plate on the former. This creates large amounts of water dust with considerable noise generation. As far as the bearings are hit by the high pressure water jet, they are exposed to considerable wear. Especially if the high-pressure water jet carries along abrasive particles, the underside surface of the material plate can be affected as a result of rebound effects, in particular it can be matted.

The invention is based on the object of creating a method and a device of the type known from US Pat. No. 5,111,652 A, which avoid water losses during downtimes. Such downtimes occur both briefly during the cutting of a material plate and in longer work breaks.

In terms of the method, this object is achieved in that the chamber is located in a water circuit and that the inlet opening is released immediately before the high-pressure jet begins to cut.

In one embodiment of the invention, the water circuit is switched on and off at least approximately synchronously with the high pressure water jet.

In terms of device, the object on which the invention is based is achieved in that the inlet opening is assigned a slide which opens immediately before the high-pressure jet begins to cut.

The method according to the invention is explained with reference to the drawing, in which an apparatus for carrying out the method is shown in a schematically simplified form. It shows:

Fig. 1 is a side view of a device for performing the method according to the invention and

Fig. 2 is a front view of the device.

In the device according to FIG. 1, a material plate, for example a pane of glass 1, is cut in an approximately vertical position by means of a high-pressure water jet emerging from a nozzle 2. The glass pane stands on a horizontal conveyor comprising transport rollers 4 and rests against a slightly inclined support wall 5. The support wall is located in a machine frame 6. Such support walls, which allow a low-friction horizontal transport of the glass pane 1, are in the form of roller fields, roller fields and air cushion walls

AT 41 1 158 B known in particular as part of insulating glass production lines. The support wall is interrupted by an approximately perpendicular slot 7 (see FIG. 2). Approximately at the level of the slot in front of the support wall there is an approximately vertical guide column 8 which carries the nozzle 2 on a slide 9, the axis of which is at least approximately perpendicular to the plane of the glass pane 1 and passes through the slot 7. The nozzle 2 can be moved along the column 8 by means of drives not shown and is supplied via a connection 3 with water under high pressure, to which abrasive particles are mixed, from a high-pressure pump known per se and therefore not shown. By successively moving the nozzle 2 along the column 8 or the glass pane 1 by means of the horizontal conveyor 4, the glass pane 1 can be cut along any lines that are perpendicular to one another. By simultaneously moving both the nozzle 2 and the glass pane 1, which are coordinated with one another, curved cutting lines can also be followed.

The high-pressure water jet crosses the slot 7 and hits an opening in a water-filled chamber 10 behind the supporting wall. The chamber 10 can be moved on a vertical column 11 in synchronism with the nozzle 2. In the end wall of the chamber 10 facing the support wall 5, an inlet opening 12 for the high pressure water jet is located in the extension of the axis of the nozzle 2. The inlet opening 12 can be closed via an indicated slide 12a with an actuator (not shown). The distance between the end wall and the back of the support wall 5 and the diameter of the indicated water jet are shown in an exaggerated manner. The chamber 10 is supplied with water from a tank 13 via a pump 14, a filter 15 and a hose 16 via an upper connection 10a. The water runs back into the tank 13 via a lower connection 10b. An overflow line 17 prevents an overpressure in the chamber 10.

When the pump 14 is switched on, the slide 12a is opened immediately before the high-pressure water jet begins to cut. The high pressure water jet emerging on the rear side of the glass pane 1 crosses the gap in the supporting wall 5 and enters the water-filled chamber 10 via the opening 12 in its end wall. As a result, the still considerable, remaining kinetic energy of the high-pressure water jet is destroyed with little noise and with the formation of only small amounts of water dust.

Figure 2 shows a greatly simplified front view of the device. The gap 7 extends over the entire height of the support wall 5. The double arrows A and B symbolize the direction of movement of the nozzle 2 along the guide column 8 on the one hand, and the glass pane 1 on the transport rollers 4 on the other. The transport rollers can be driven in a manner known per se. Instead, an indicated entrainment device, consisting for example, can above the transport rollers 4 a guide rail 20, which can be moved via a rack and a stepping motor (not shown), and a suction head 21, which can be placed against the front of the glass pane 1, can be provided. Such transport devices are known per se to the person skilled in the art and therefore do not require any further explanation.