DE2920695A1 - Multi:platen hot press ensuring uniformly horizontal lift - has four pairs synchronising cylinders with pressure control unit - Google Patents

Abstract

During the closing of the movable crosshead of a multi-daylight, hot press for chipboards, hard fibre panels, etc. the hydraulic fluid expelled from the differential or annulus chambers of the synchronising cylinders, enters the forward side chamber of one of each pair of synchronising cylinders, assembled for pref. with one pair at each corner of the crosshead. During the lowering of the crosshead, the hydraulic medium to be expelled from the forward side chambers is returned to the annulus chambers, but the forward side of one cylinder of each pair is not loaded with fluid. It ensures that the lifting and lowering of the moving crosshead and the platens carrying the materials, takes place as uniformly as possible, so that the highest possible degree of quality and accuracy of the prod., together with continuous working of the press are achieved. The platens are lifted smoothly and parallel without any spilling of the materials. When pressing is carried out without spacers, the nominal spacing between the platens can be ensured easily.

Description

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- 3 Becker & van Hüllen Niederrheinische Maschinenfabrik GmbH & Co.

Untergath 100, 4150 Krefeld

Hydraulic press, in particular multi-daylight heating press

The invention relates to a hydraulic press, in particular a multi-daylight heating press, with press frame, e.g. B. chipboard press, rubber plate press, plastic plate press or the like with a movable and stationary press beam, the stroke of the movable press beam by a plurality of hydraulically driven Piston-cylinder arrangements are made with the connection of synchronizing cylinders, as well as plates arranged between these spars, which are moved vertically by a heating plate closing device

In general press construction have so far been used to achieve uniform Stroke mechanical devices, such as racks, gears, worms, spindles, etc., known, but the availability in terms of Beiast. Controllability, control and accuracy are inadequate j

and the z. B. on multi-daylight presses from the product required ι

The quality requirements for synchronism are no longer sufficient.

At z. B. in DE-AS 27 18 961 describedei equal stroke control hydraulic pull and pressure cylinder, as also with still "known" Equal stroke devices, such as B. flow regulators, measuring and metering pumps

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as well as equal stroke systems with blocked cylinders and the like are equal stroke controls in which forces are transmitted and which are used in any case as a lifting system and with which a maximum degree of synchronization accuracy cannot be achieved.

The invention is based on the object of a hydraulic press of the type described in more detail at the outset so that the lifting and lowering process of the movable press beam and the product-carrying Plates are made so evenly that a maximum of product quality, product accuracy and press service life is achieved will.

According to the invention, it is proposed in such a press that that during the closing process of the movable press beam from the differential spaces diagonally to the press beam, preferably in pairs arranged synchronizing cylinder, the displaced hydraulic medium enters the cylinder spaces via connecting lines,. and that at Lowering of the movable press beam, the hydraulic medium to be displaced into the cylinder spaces via the connecting lines into the Differential chambers arrives, the cylinder chamber not having hydraulic medium applied to one of the synchronous cylinders arranged in pairs is.

Further embodiments of the invention emerge from the sub- " Sayings.

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The inventive solution is a precise exchange of preloaded hydraulic medium in diagonally arranged presses Cylinder chambers achieved a uniform movement of the stroke.

The inventive attachment of the synchronizing cylinder to the outer Frame sides on the one hand and on the movable press beam on the other hand has the advantage of having a large number of propulsion and plungers liftable and lowerable press beam so evenly and controlled to move during the entire lifting and lowering process that in particular during the slow closing stroke in the phase of contact between the bulk material and the heating plates above it due to the uniform slow and parallel approaches no "blowouts", d. H. no reject plates arise. This is especially true when pressing of chipboard with embankments that have the finest surface layers, a smooth, even, parallel and jolt-free approach is required is.

According to the invention, another essential advantage is offered by chipboard multi-opening heating presses, if there are no spacer bars at the level of the nominal chipboard thickness between the individual press floors, Instead, the target chipboard thickness is to be produced precisely and without spacer strips via displacement sensors. This is where the even pressing process comes through the synchronous cylinder enables precise positioning of the target distance, thereby ensuring higher product accuracy and preventing frequent The positioning pistons respond and thus also the switching valves. . _ 6 -.

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It is also advantageous that in the case of extremely one-sided pouring of the chip fleece, inclinations of the heating plates and the movable press beam, which have a negative effect on the guides of the press beam, the heating plates, the piston guides and in terms of load and wear
Seals and their fastening elements and affect the frame load, thereby preventing the spar misalignment inevitably increasing the pressure of the synchronizing cylinder spars and
if an impermissibly high inclination is reached, the press is switched off by the pressure switch and acoustic and optical signals are used to protect it
be sent.

The sealing elements in the locking and pressing cylinders cause the ¹ ,

Switch to the necessary slow travel without synchronizing cylinder the j known "stick slip" effect, i.e. the pistons and thus the press beam j

with the connected heating plates move upwards and jerkily.

negatively affect the product quality (blown out). Further be.

i the service life of the sealing and guide elements due to the "stick slip" effect

significantly reduced and the downtime of the press increased .. Due to the |

According to the invention, there is no need for the stick to attach the synchronous cylinder
slip "effect and the associated negative effects.:

The preload also has an advantageous effect on the product accuracy the synchronizing cylinder, which can be set to a specific pressure using the pressure switch. Without preload, a

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larger compression volume of the hydraulic medium, which reduces the response accuracy of the compensating cylinder. Through this Preload, the tolerance of the misalignment is significantly reduced, which is particularly beneficial in terms of product quality and accuracy. At the same time, the synchronizing cylinders are able to the aforementioned negative effects of the cuff rubs, the Compensate compression and propulsion piston.

The arrangement of the differential synchronization in pairs is spatially advantageous cylinder on the outer frame sides by a short construction in length. There are unnecessary, costly foundation deepening, which would be necessary when using simple cylinders without a differential surface, avoided. At the same time, the attachment of the Synchronous cylinder in the lower part of the press has the advantage that it is not affected by j

Heat radiation, ζ. B. the heating plates are affected in their accuracy. To heat Dehnunger: to press the movable Holmes balance out ', it is also advantageous to the synchronizing cylinder piston and cylinder side on the beam and frame with universal joints _to; attach.

In kurzhübigen hydraulic presses but can also possibly the use \ simple double-acting cylinder, since no differential area, due to the short stroke, the lengths are low. :

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Exemplary embodiments of the invention are shown schematically in the drawings shown. Show in detail

1 shows a part of a multi-daylight heating press in two views,

a hydraulic scheme.

Figure 1 shows the two outer areas of the lower section a multi-daylight heating press in a frame construction with a movable press beam 9, the lock cylinders 21, the press cylinders 20 and the press frame 17. On the outside of the frame plates there are pairs of synchronizing cylinders 1 to 4, which are in universal joints 18 and 19 are arranged once on the press frame 17 and on the other on the underside of the press beam 9.

In Figure 2, the operation of the synchronous cylinder 1 to 4 can be seen. There are in each case the differential or cylinder chambers of the synchronizing cylinders 1 and 3 or 3 and 4 via the connecting lines 10 to 13 connected. During the closing stroke of the press, ζ B.

Synchronizing cylinders 1, the hydraulic medium of the differential chambers 5 in the

Cylinder space 6 * of a synchronizing cylinder 3 is pressed, with the exchange of the differential chambers 5 ^{J of} the synchronizing cylinder 3 in the cylinder chamber 6 of the synchronizing cylinder 1 taking place at the same time. The exchange of the differential spaces 7, 7 ^J and the cylinder spaces 8 and 8 'of the synchronizing cylinders 2 and 4 takes place accordingly. Exactly the other way around, the exchange takes place

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of the hydraulic medium from the differential or cylinder chambers Return stroke. Rooms 6 "and 8" are not taken into account.

Via the pressure switch 14, the synchronizing cylinders are set to the necessary Pre-tensioned pressure. If there is a misalignment, the pressure in the associated corresponding differential or cylinder chambers increases the permissible level, the pressure switch 15 secures the press by continuing would emit signals.

By control unit 16 are expediently before each press stroke the differential or cylinder chambers are depressurized and pressurized again. This has a different effect on the accuracy of the synchronism negative influences, such as temperature and viscosity influences, with the same starting conditions for each stroke for all synchronizing cylinders to be recreated.

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1 Synchronous cylinder 2 Synchronous cylinder 3 Synchronous cylinder 4th Synchronous cylinder 5 Differentiation space 5 * Differential space 6th Cylinder space β ' Cylinder space β " Cylinder space 7th Differential space r Differential space 8th Cylinder space 8 ^# Cylinder space 8th" Cylinder space 9 Preeeenholm. movable 10 Connecting line 11 Connecting line 12th Connecting line 13th Connecting line 14th Pressure switch IS Pressure switch 16 Control unit 17th Press frame 18th Universal joint 19th Universal joint 20th Prefl cylinder 21st Lock cylinder

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Claims (3)

• t ι • I ι Jl) • · I, • · C ■ I ι> » Becker & van Hüllen Niederrheinische Maschinenfabrik GmbH & Co. Untergath 100, 4150 Krefeld Expectations (l7) Hydraulic press, in particular multi-daylight heating press, with press frame, e.g. B. chipboard press, hardboard press, rubber plate press, plastic plate press o. The like., With a movable and stationary press beam, the stroke of the movable press beam is carried out by a variety of hydraulically driven piston-cylinder arrangements with synchronization of cylinders, as well as plates arranged between these beams, in particular heating plates , for receiving the pressed material, which are moved vertically by a heating plate closing device, characterized in that the during the closing process of the movable press beam (9) from the differential ^{spaces (5) or (5 J} ) and (7) or (7 ') the parallel cylinder (1) or (3) and (2) or (4), which are arranged diagonally to the press beam, preferably in pairs, displaced hydraulic medium into the cylinder spaces (6 ') or (6) and (8 ^J ) or (8) Connecting lines (10) or (11) and (12) or (13) arrives, and that during the lowering process of the movable press beam (9) the hydraulic medium to be displaced of the Z cylinder chambers (6) or (6 *) and (8) or (8 ') via the connecting lines (11) or (10) and (13) or (12) into the differential chambers (5 ^J ) or ( 5) and (7 ^J ) or (7) 030049/0150 t >>) I f > I. (I ■ reaches, the cylinder space (6 ^M ) or (8 ″) each of one of the synchronous cylinders arranged in pairs not being acted upon by hydraulic medium. 2. Hydraulic press according to claim 1, characterized in that the differential spaces (51, (5 '), (7) (7 *) and the cylinder spaces (6), (6 *), (8), (8 ') are biased to a variable pressure which by a pressure switch (14) is adjustable. 3. Hydraulic press according to claims 1 and 2, characterized in that that with a defined pressure increase of the differential and cylinder spaces (5 to 8 *), caused by exceeding the maximum permissible inclination of the movable press beam (9), the stroke of the bar is interrupted by the adjustable pressure switch (15). 030049/0150