US3398844A

US3398844A - Feeding and discharging arrangement for multilayer presses

Info

Publication number: US3398844A
Application number: US515026A
Authority: US
Inventors: Carlsson Bengt; Hedin Borje
Original assignee: Motala Verkstad AB
Current assignee: Motala Verkstad AB
Priority date: 1964-12-21
Filing date: 1965-12-20
Publication date: 1968-08-27
Anticipated expiration: 1985-08-27
Also published as: DE1436920C3; DE1436920A1; SE310552B; DE1436920B2; FI42473B; NO116489B; FR1460484A

Description

7, 1968 B. CARLSSON ET AL 3,398,844

FEEDING AND DISCHARGING ARRANGEMENT FOR MULTILAYER PRESSES Filed Dec. 20, 1965 5 Sheets$heet 1 INVENTOR,

Hang-f C'ar/ssoh arje. l/ea l'n ATTORNEYS 7, 1968 B. CARLSSON ET AL 3,398,844

FEEDING AND DISCHARGING ARRANGEMENT FOR MULTILAYER PRESSES 3 Sheets-Sheet 2 Filed Dec. 20, 196E INVENTURS 68031 Car baa flarg e #2 do; BWEWMJM 7, 1968 B. CARLSSON ET AL 3,398,844

I FEEDING AND DISCHARGING ARRANGEMENT FOR MULTILAYER PRESSES 3 Sheets-Sheet 3 Filed Dec. 20, 1965 INVENTORS Eeog far/sea v 160*)8 l /ez/in fM jg ATTORNEYJ United States Patent "ice 3,398,844 FEEDING AND DISCHARGING ARRANGEMENT FOR MULTILAYER PRESSES Bengt Carlsson and Borje Hedin, Motala, Sweden, as-

signors to Aktiebolaget Motala Verkstad, Motala, Sweden Filed Dec. 20, 1965, Ser. No. 515,026 Claims priority, application Sweden, Dec. 21, 1964, 15,497/64 9 Claims. (Cl. 21416.6)

ABSTRACT OF THE DISCLOSURE Apparatus for feeding and discharging workpieces into and from storey openings formed by a multilayer press, said apparatus including a platform for each of said storey openings adapted to register with the openings and move to and from the openings. Means are provided for supplying fluid under pressure through a plurality of apertures formed in the upper surface of each of said platforms for producing a cushion of fluid over the platforms in order to facilitate the introduction and removal of the workpieces to and from the platforms.

The present arrangement relates to a feeding and discharging arrangement for multilayer presses, particularly those used in hot pressing of wet formed fiberboard.

When manufacturing fiberboard according to the wet method first wet sheets are formed comprising mainly fibers and water in a weight ratio of between 1:3 and 1:1. The wet sheets are then introduced in batches into a hot press, usually having 20-25 storeys where, between hot pressing plates, they are subjected to first a high pressure of short duration for the purpose of mechanically reducing the water content, and then to a lower pressure under which the remaining water content evaporates and the fibers bind together. To facilitate the draining of water and steam from the wet sheets during the pressing operation they are allowed to rest on wire gauze, a so called drainage wire.

Changeable glazing plates, usually consisting of mm. polished stainless metal sheet, are mounted on the ceiling of each storey opening, i.e., on the underside of each upper plate, for the purpose of obtaining on one side of the fiberboard a smooth and uniformly colored surface. Since the glazing plates are only secured to the perimeter of the press plates, they tend to sag in open presses, and in wide presses the amount of sag can reach up to 25 mm. or more thus restricting the free height of the open- A wire gauze, a so called intermediate wire, is mounted between the glazing plate and the upper press plate in order to soften the effect of soot which accumulates there as a result of air and impurities being sucked in and burning solid to the plate every time the press is opened. In spite of the measures adopted it is often neessary to reduce the speed at which the press is opened which, as experience shows, reduces the formation of soot but at the same time increases the length of the pressing cycle. The intermediate wire gauze retards the transfer of required effective heat from the press plate to the wet sheet thus extending the time taken for the sheet to dry and thereby also the pressing cycle.

The weak state of the wet sheets will not permit them to be dragged or displaced onto flat supporting surfaces much less a wire gauze. Consequently the wet sheets require transport members which accompany them when they are introduced into the press openings. These are sometimes made of wire gauge which remains in the press while pressing is taking place, thereby also serving as 3,398,844 Patented Aug. 27, 1968 drainage wires. The transport members are more often made up of steel plates, so called transport plates, covered by a drainage wire which accompanies the platesxThis latter alternative is usually preferred since it permits a rapid recharging of the press and can be accomplished with mechanically simple equipment.

The system of transport plates, however, is encumbered with several disadvantages, some of which will be men'- tioned below. The transport plates require a return conveyor which is expensive and occupies a lot of space. The transport plates become worn, particularly on'being fed into and out of the press, and make it necessary to cover the costly pressing plates with wearing plates which also soon become worn out. Unavoidable variations in size of new transport and wearing plates and increased variations due to wear, result in a poorer quality of the pressed product.

The rapid changes in temperature of these plates during the first part of the pressing period create internal stresses which become evident in the form of buckling when the press is opened. The buckles restrict the free height of the press opening on charging and cause extensive local wear on the plates. The large mass of the transport plates requires considerable amounts of heat during the pressing process and normally answers for 15-30% of the total heat consumed by the press. This unfavorably influences the time required for a pressing sequence.

The object of the present invention is to transport the Wet sheets, following in sequence from a forming machine, mechanically and simply into a multilayer press in batches without any part of the feeding or discharging device being included in the pressing operation or causing any component taking part in said operation to wear; to make it possible to mount the glazing plates on the floor of the press opening, i.e., on the upper surface of the pressing plates, thus rendering the intermediate wire superfluous, and to enable the finished pressed sheets to be discharged at the same time as non-pressed sheets are fed in.

The above object of the invention is achieved by means of the arrangement according to the invention in that said arrangement has obtained the characteristics disclosed in the claims.

The invention will now be more closely described with reference to the accompanying drawings, where:

FIG. 1 shows diagrammatically a perspective view of an arrangement according to the invention,

FIG. 2 shows perspectively and in section a portion of the same arrangement at the beginning of the feeding operation, and

FIG. 3 shows perspectively and in section the same por-' tion when the feeding operation is completed.

Shown in the drawing is a multilayer press having an upper stationary press tatble 1 and a lower mobile press table 2 which obtains its pressing movement from a piston-cylinder device 3. Arranged between these members are press plates 4 forming between them storey openings which are closed during the actual pressing operation by the lower press table lifting the pressing plates from the shown resting position in a manner known per se.

Arranged at the feeding end of the press a feed hoist 5 is provided with a roller table 6 and two posts 7 on which are arranged roller tracks formed by shelves 8, one for each storey and post. The hoist is operated by a piston-cylinder device 9. A feed-in carrier 10 in the form of a carriage and comprising two uprights 11 supporting platforms 12, is arranged on the feed-in hoist 5. The carriage rests on the roller table 6 by means of wheels 13 mounted on the uprights 11, and on the shelves 8 by means of a pair of supporting rollers 14 mounted on each side of the free end of the platforms, these rollers i 3 being deleted from FIG. 1 in the interest of clarity. Movement of the carriage is caused by one or more piston-cylinder arrangements 15. A roller conveyor 16 is arranged to advance wet sheets A from a forming machine (not shown).

At the discharge end of the press is a discharge carrier 17 in the form of a hoist. The hoist is driven by means of a piston-cylinder arrangement 18. The carrier 17 is provided with slides 19 for finished sheets B. A conveyor belt, 20 is arranged so that when the carrier is lowered it passes through a gap in each 'slide 19, in this way lifting the sheets from said slides and carrying them away from the press. Having left the slides 19, the edge portions of the sheet B are supported by roller conveyors 21.

As can be seen from FIG. 3, the platforms consist of two tubes 22 extending in the longitudinal direction of the press and supporting between them a floor 23. The interior of said tubes 22 communicates with cavities 24 which, via holes 25 in the upper surface of the floor communicate with the under surface of the wet sheet A lying on said floor 23. The tubes 22 are securely connected to the tubular uprights 11 by means of which the platforms are connected to a source of compressed air, in a manner not shown, so that when air is required it can be blown out through the holes 25.

The floor 23, at the forward end of platforms 12, is designed with a lip 26 projecting forwardly and downwardly between the wheel pairs 14, the end of said lip terminating directly above a glazing plate 27 mounted on press plate 4. Stretched out under the press plates are drainage wires (not shown).

Located at the feed end of the press are fingers 28, securely connected to shafts 29 carried in bearings or the like (not shown) in the shelves 8. An extra pair of shelves or similar bearing carriers must be provided at the upper end of the two posts 7 to provide support for the uppermost shaft 29. One end of each shaft is securely connected to a crank 30 pivotally connected to a connecting bar 31 common to all cranks 30. By means of bar 31 each of the fingers 28 can be positioned so that they either point straight downwards and obstruct the wet sheet lying on the floor 23 or so that they lie folded along the edges of the shelves 8. Displacement of bar 31 is effected by means of a pneumatic piston-cylinder arrangement 32 (FIG. 1). The feeding and discharging arrangement functions in such a manner that the wet sheets A advancing on the roller conveyor 16 are fed in sequence into the carrier 10 each on its platform 12 by, at least in the platform which is just being occupied, blowing air through the holes 25 so that the wet sheet supported by the air over the platform can be advanced to the required position, after which the hoist is raised or lowered until an unoccupied platform reaches the feed position. When the hoist is fully loaded it is moved into the open press with a platform 12 in each storey opening (FIG. 2), whereby the platforms push the finished pressed sheets in front of themselves by means of a lip 26, into the discharge hoist 17, the support rollers 14 moving along the press plates. The fingers 28 then are turned so that they prevent the wet sheets from following the platforms as the latter return, which is effected by blowing air out through the holes 25 in the upper surface of the platforms whereby the portion of the wet sheet which lies over the platforms is held floating on the air and the remaining, successively increasing portion rests on the glazing plates. The hoist 17 is lowered so that the sheets are unloaded in sequence from the slides 19 and carried away by the conveyor belt for further treatment.

In the embodiment described, air has been used to facilitate the longitudinal movement of the wet sheet over, and in relation to the platform, but it is also possible to use other gases or liquids, such as water for example.

.4 The desired members which effect the movements of the hoists, carriers and fingers can naturally be replaced by other known means, e.g., electromechanical means.

When wet sheets of a smaller size, e.g., smaller than the largest used, are to be pressed, it may be desired to reduce the air consumption by preventing the air from flowing out of the holes nearest the long sides of the platforms. Naturally it is also possible to arrange the described embodiment so that it uses less air, e.g., by shutting off the holes in the platforms which open out into the surrounding air from the source of compressed air while the wet sheet is being fed in and discharged.

We claim:

1. Apparatus for feeding and discharging workpieces into and from storey openings formed by a multilayer press, said apparatus comprising a frame disposed adjacent said press; a platform for each of said storey openings, said platforms being carried by said frame and positioned to register with said storey openings, each of said platforms comprising a floor having a plurality of apertures formed in the upper surface thereof, a pair of tubular uprights disposed at one end of said floor, a pair of longitudinal tubes extending to the sides of said floor and normal to said uprights in registry therewith, and a plurality of transversely extending cavities formed underneath said floor, and registering with said tubes and said apertures; and means to supply fluid under pressure to said uprights for producing a cushion of fluid over said upper surface of the platforms in order to facilitate the introduction and removal of said workpieces to and from said platforms.

2. The apparatus of claim 1, wherein roller members are disposed on one end of each of said uprights and on the other end of said floor.

3. The apparatus of claim 2, wherein said frame comprises a table adapted to be engaged by the roller members on said uprights, and a pair of roller tracks fixed with respect to said table and adapted to be engaged by the roller members on said floor.

4. The apparatus of claim 3, further comprising means to reciprocally move said table to position said platforms with respect to said storey openings.

5. The apparatus of claim 1, wherein said means to move said platforms comprises at least one piston-cylinder device operatively connected to said platforms.

6. The apparatus of claim 1, further comprising a plurality of finger members movably mounted with respect to said frame between a first position in which they permit said platforms and the workpieces thereon to pass freely into said storey openings, and a second position in which they engage the workpieces to retain same in said storey openings upon removal of said platforms from said storey openings.

7. The apparatus of claim 6, further comprising a horizontal shaft for each of said sets of finger members and means to rotate said shafts to effect said movement of said finger members. v

8. The apparatus of claim 1, further comprising alip projecting forwardly from the free end of each of said platforms and adapted to engage workpieces which have been previously pressed in said storey openings upon movement of said platforms into said storey openings.

9. The apparatus of claim 1, wherein said pressure fluid is air.

References Cited UNITED STATES PATENTS 2,728,468 12/1955 Siempelkamp 2l416.6 2,805,898 9/1957 Willis 214 1 3,141,706 7/1964 Curtenius 214-1);

HUGO O. SCHULZ, Primary Examiner.