EP0634253B1 - Press, in particular a platen press for woodworking - Google Patents

Abstract

A press (11), usable in particular as a platen press for woodworking, generates the pressing pressure by means of two superposed rows (20, 21) of flexible tubes (19) which are filled with compressed air. An intermediate plate (17) ensures pressure equalisation. The pressing surfaces are formed by heated platens (29), the bottom one of which can be partly pulled out beyond the press frame to facilitate charging and cleaning. <IMAGE>

Description

The invention relates to a press, in particular a plate press for woodworking or machining similar workpieces. The press is e.g. for gluing plate-shaped materials designed under temperature and pressure, especially for the production of veneered or plastic-coated panels.

WO-A-82/02509 discloses a press with a press drive thanks to pneumatically expandable bellows-like bodies. Two rows these bodies are arranged one above the other. Everyone is supported on an upper plate fixed to the frame and acts downwards onto a vertically movable plate. The two Movable plates of the hose rows are by means of stud bolts connected to each other, so that with the same stroke as in a Double the pressing force is achieved.

EP 131 801 B1 and EP 176 498 B1 also include plate presses become known in which the pressing force by pneumatically inflatable tubing is applied. Such Plate presses come with relatively little mechanical Effort and are therefore particularly for repair shops etc. well suited.

A press is known from US-A-2 363 779 (closest prior art) become, in which the lifting mechanism of the press table several Groups of superimposed Contains hoses.

A press is known from CH patent specification 273 477 become, whose press table from the area of the rigid press frame sideways out to make it easier to be able to load.

TASK AND SOLUTION

The object of the invention is to produce plate presses of this type to develop further and in particular their area of application enlarge and thus make them more universally applicable.

According to claim 1, the tubes are in at least two rows of tubes with their Ends and in particular with their end pneumatic connections in the longitudinal direction of the hose offset from each other. So that can the hoses despite certain thickening at the ends and especially the connections in the smallest space and with only small thickness of the intermediate plate can be arranged because the End connections are then staggered. So it is advantageous also possible the hoses of the two rows of hoses to each be of the same length.

It is particularly preferred if the tubes of the two Rows of hoses from different sides with compressed air be loaded, i.e. their end connections to each opposite hose ends. This will not only ensured that the possibly occupying space Hose connections are better to arrange, but it will also an equalization during the pressing process, especially on Start of the pressing process. Although of course pneumatic pressure in every hose at every point itself evenly, is influenced by various influences, for example the inflation characteristics of the hoses, certain restoring forces in the hose material itself, etc., the Usually start the hose on the injection side first, inflate and only then the pressure across the entire Forward the hose length. By the opposite Arrangement of the blowing sides remains the press plate horizontally, without further measures being necessary. A similar effect can be achieved if each other Adjacent hoses of the same row of different ones Ends are connected, although then the intermediate plate may get a more uneven load.

An embodiment of the invention is shown in the drawing and will be described in more detail below explained. Show it:

FIGURE SHORT DESCRIPTION

Fig. 1

a partially sectioned front view of a Press,

Fig. 2

a shortened side view the plate press,

Fig. 3

a perspective sectional view of a Details of a hot plate,

4 and 5

Views corresponding to Figure 1 in two Working positions, and

Fig. 6

a schematic arrangement and circuit diagram the pneumatic connections of the press hoses.

DESCRIPTION OF THE EMBODIMENT

The drawings show a press 11 from the end face 42 seen. The right side is cut on the one hand and on the other hand shown in the closed state while the left side of the drawing shown in view The plate shows in the open state.

A press frame 12 has an upper and a lower one Carrier plate 13, 14, each in the longitudinal direction of the plate running wide-flange double T-beams assembled are and thus a stiffened structure with individual longitudinal chambers form. These carrier plates are so designed that their flatness even with the greatest achievable pressing pressures maintained.

At their four corners are the long rectangular support plates 13, 14 interconnected by vertical supports 15 which protrude from the bottom over the lower plate 14 and there have rollers 16 so that the press easily is movable.

Are on the lower support plate 14, each of intermediate plates 17, 18 underlaid, two rows of tubes 20, 21 arranged. They consist of hoses 19 made of flexible material, for example rubber or plastic, possibly with fabric inserts or the like, and extend over the entire press length (see Fig. 2). The hoses of the two rows of hoses are of the same length, however, as can be seen from FIG. 2, offset against one another, that their ends 22 and possibly connections 23 against each other are offset. Each hose has a pneumatic connection 23 on one or more distributors 24 (in Fig. 6: two distributors) and a common compressed air connection 25 are supplied. This is not a single one shown pneumatic circuit 26 connected upstream a conventional compressed air network 27 or a compressor becomes.

The pneumatic circuit 26 (FIG. 6) contains a pressure regulator 50, at which the desired pressure can be set. This pressure can be read off a manometer 51. On in the pneumatic line 52 switched on safety solenoid valve 53 ensures that the press only by Pressurization can be closed when a switch 54 is closed, the part of a touch guard is, for example by a rotating around the press Safety line. It provides in connection with the switch 54 for the fact that the press cannot be closed as long as Operator still has a hand in the press or the like ..

The trigger pulse is via a valve 55 and a button 56 given to close the press. Relieving the pressure a 3-way ball valve 57 is used to open the press with a large outlet cross-section, which may be via a silencer 58 releases the compressed air from the hoses.

A safety valve 59 secures the pneumatic system against Overpressure.

In one behind the pressure regulator, but in front of the safety valve 53 branching pneumatic line 60 is a pressure take-over valve 61 provided. This is a not electrically, but only pneumatically operated Valve, which has a control feedback 62 in the press direction having. It can be set so that it falls below of a set pressure opens and any Compensates for pressure losses in the system.

Fig. 1 shows that the hoses of both rows are parallel to each other and are arranged one above the other. you The distance should be chosen at least so large that the Hoses next to each other in a flat, i.e. unfilled state can lie on the intermediate plates 17, 18.

On an upper plate 28 which is the top row of tubing covers, is a heating plate 29 and is together with this vertically movable. Also on the underside of the upper carrier plate 13 a corresponding heating plate 29 is accommodated. Their heating surfaces facing each other form each upper and lower pressing surfaces 30.

The structure of the heating plates 29 can be seen from FIG. 3. The Base body 31 of the heating plate is plate-shaped and has grooves 32 on the top for receiving heating conductors 33. The base body is made of aluminum. The heating conductor 33 include electrical heating resistors 34 which are of an electrical insulation 35 are surrounded, for example through multiple glass fiber braiding and braiding with a protective film made of polytetrafluoroethylene (PTFE).

The grooves 32 are through one on the base body 31 Adhesive attached cover plate 36 in the form of a sheet a good heat-conducting alloy.

The base body 31 is made of an insulating layer 37 high pressure compressed mineral fiber under which one High-pressure insulating plate 38 made of highly compressed fiber material (Chipboard or the like), optionally with a phenol resin bond is. This heating plate has very good press surface 30 Heat transfer properties while the back with an effective insulation that can withstand high pressures is provided.

2, 4 and 5 it can be seen that the lower Heating plate 29 slidably guided relative to its base is. For this purpose, the heating plate 29 has two of its outer longitudinal sides Guide strips 65 along the outer edges 66 of the insulating plate 38. This is with the the hoses 19 top plate 28 firmly connected, while the heating plate 29 only transfers pressure on it lies on.

With a handle 67 (Fig. 4 and 5), the heating plate So, sliding on the insulating plate 38 in the illustrated Example pulled up to about half from the press frame until a stop 68 the further shift stops and thus prevents the heating plate 29 from tipping over. With appropriate comprehensive leadership, however, one could also be pulled out further.

It can also be seen that the electrical connection of the lower Heating plate via a flexible cable 69 from a connection device 70 takes place so that the heating plate movement is possible is. This allows the heating plate to be loaded more easily and / or partially pulled out of the press for cleaning become.

The heating conductors are provided with a heating control that is not shown in detail and also thermal Control elements for heating can contain.

FUNCTION

The press works as follows:

In the open state of the press (Fig. 1 left) lower pressing surface 30 with the material to be pressed loaded, the press nip 40 is quite large and one enables convenient loading. Another relief the feed offers the pull-out of the heating plate 29 (Fig. 5). The tubes 19 in the tube rows 20 and 21 are depressurized and emptied so that they have two flat layers 41 form.

After loading, the hoses 19, namely in both layers each have two different end faces 42 the press forth (Fig. 2 and 3) via the pneumatic circuit 26 and the distributors 24 and the pneumatic connections 23 Compressed air admitted. For this purpose, the pressure regulator 50 is on the desired pressure and set the button 56, so that valve 55 opens. The safety valve 53 stops the build up of pressure when it is opened by the safety switch is closed. The hoses fill up and lift the intermediate plates 17 and 28 and the ones on it attached heating plate 29 and the workpiece placed thereon and finally push it to the bottom of the top Heating plate 29. Both plates can be heated.

This makes it possible to get a fairly large stroke without the hoses being too large in diameter have to. This saves compressed air because e.g. two half-diameter hoses one on top of the other require much smaller total volume of air than one Double diameter hose. Furthermore, the large hoses a fairly large distance from each other have so that the overlying press plate stronger Would be exposed to stress.

Through the uniform application of the entire press surface with the pressure coming from the hoses a very uniform contact pressure achieved without major mechanical Effort is necessary. It just has to take care of it be that the intermediate plates 17 and 28 and the lower heating plate 29 can move vertically. Through the Arrangement of, for example, eight hoses per row of hoses with a freely inflated diameter of, for example 80 mm, which are at a mutual distance of about 130 mm parallel to each other over the entire press length of, for example 2.5 m is a press stroke of about To ensure 120 mm. The hoses are at their ends clamped between guide strips 43, which also for the ensure the necessary distance between the hoses.

The circular, flexible hoses 19 create themselves the plates 17, 18, 28 flat and thus transmit the Press pressure well distributed. The one between the two rows of hoses provided, vertically movable rigid intermediate plates have a mechanical balancing effect and thus promote an even application of the pressing force.

Since the valve 55 is released again after the button 56 is released closed, the pressure take-over valve 61 ensures that the pressure set there or on the pressure regulator 50 is not undercut if there is a pressure loss due to leakage occurs.

After the processing time, the air from the tubes 19 drained, and that via the ball valve 57 and down of the pressure on the regulator 50, whereby the lower pressing surface lowered and the workpiece can be removed.

The press therefore has a rigid frame-shaped press frame with a stiffened upper and lower support plate on. Due to the large stroke it is possible without any Adjusting means, i.e. with rigid support plates a relative large area of editable plate thicknesses. The press is therefore very simple to build, since the top and bottom Plates of simple rigid structures, for example made of double flange beams composed, can be.

Because the hoses of the rows of hoses are each vertical are hardly on top of each other on the intermediate plates Bending forces applied and the force flow becomes immediate introduced from the press surface into the lower support plate. If larger strokes are required, more can be done can be used as two rows of hoses. Although one horizontal arrangement (vacuum press) with bottom movable press surface is put through, others can Arrangements with multiple hose levels can be performed. It should separate hoses in the superimposed Rows can be used.

In that the hoses are arranged in the longitudinal direction of the press you get a smaller number of hoses and still ensures a tight occupancy.

Claims (6)

1. Press, particularly a platen press for woodworking, with a press drive by pneumatically inflatable hoses (19), in which there are at least two superimposed rows (20, 21) of hoses (19), characterized in that the hoses (19) in at least two hose rows (20, 21) are arranged with their ends and in particular with end pneumatic connections (23) in mutually displaced manner in the hose longitudinal direction.
2. Press according to claim 1, characterized in that the hoses (19) of the hose rows (20, 21) are in each case of the same length.
3. Press according to one of the preceding claims, characterized in that the hoses (19) of different hose rows (20, 21) provided on one side with end pneumatic connections (23) have said end pneumatic connections (23) at different ends (22) of the hoses (19).
4. Press according to one of the preceding claims, characterized in that in each case adjacent hoses (19) in a hose row (20, 21) alternately have end pneumatic connections (23) at one or other end (22).
5. Press, particularly a platen press for woodworking according to one of the preceding claims, with a press drive by pneumatically inflatable hoses (19), with a rigid, frame-like press support (12) with a reinforced, upper and lower support plate (13, 14), a plate having a pressing surface (30) in substantially horizontal manner is displaceably guided at least partly over and beyond the press support, characterized in that on their top the hoses (19) carry the plate constructed as a heating plate (29) which, with respect to an insulating plate carrying the heating plate is displaceably guided thereon.
6. Press according to one of the preceding claims, characterized in that the pneumatic press drive has a pressure takeover valve which, following a preferably pulse-controlled pressure build-up in the hoses (19), keeps said pressure above a predetermined value.

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