US2642782A - Fiberboard forming press with loader and unloader - Google Patents

Description

June 23, 1953 2,642,782

FIBERBOARD FORMING PRESS WITH LOADER .AND UNLOADER R. CHAPMAN 2 Sheets-Sheet 1 Filed April 10. 1948 INVENIvR. Pal/oh Chapman i a mi June23,1953^ R, CHAPMAN y 2,642,782

FIBERBOARD FORMING PRESS WITH LOADER AND UNLOADER Filed April 1o, 1948 2 sheets-s119912 f 5f i@ /0 M/ I' /0 f y Patented June 23, A1953 UNITED sx'mrsis.. OFFICE FIBERBOARD roRMINGfP'REss WI'rrI,l

, LOADERYAND UNLOADER Ralph Chapman, Corvallis'. Greg.; 'assig-nor' to;

Chapman Forest. Utilization;v Inez', Corvallis Oreg:,.a corporatiomof Oregonl Y Application April 10, 194S2s'eria1jNo-c z'cgas's comme. (c1. sra-c1) My presentV invention comprises anl improve'- ment in board-forming presseswherein a wet mat of fibre is consolidated into aboard by the application of heat and pressure.

In the formation of artiiicialv boards wood-, straw, cornstalks, waste paper and other types of cellulosic material maybe reducedy to indi vidual'bres by'a numberof'means'. Theprocess of reduction mayV be mechanical ink its entirety; or chemical', ora combination of the two; In the case of-V wood, theK lengths of natural' wood` may be ground to small slivers, orh may be rst' reduced to chips which arelater crushedforother; Wise reduced to'slivers andlin'dividual'bres; with or'wit-hout the aid of Steam'JiOt'Wa-ter; pressure;y orhchemical treatment; The bres'are suspended in water to form a thin slurry andl may have; associated therewith a binding agent. Forex;- ample, a phenolformaldehyde resin in incipient. C-stage may be incorporated with, the libres in" varying amounts, which resin is then precipitated upon the libres and caused to beconvertedl into insoluble, infusible, Cestage resin due' toV the4 influence of' heat` and pressure. inthe forming; press of: the present invention;

My invention comprises a forming press in" which nbre matsv formed*v inv any4 o1f"thev foregoing mannersy mayI be compressed andiheated to the desired extent` to form boards` of various thicknesses anddensities; tlie'jboardsl being of the-desiredl commercialY sizes suchas 4" x4 8".

In the operation of a press of the character described itis very difficultv to load and unload l the press` in a rapid,l eilicient manner without disrupting thelibre` mats; Heretoforey it has been the practice tou loadi presses by depositing, the mats upon long, traveling screenswhich ex-v tendi far beyond the press platens atv either or bothV sides'thereof' soV that a mat deposited upon a screen may be moved forward into the press, then, after consolidation', ejected'fromthe press while still supported upon the screen. In some, instances a mat is placedl between two such screens which travel forwardly into theY press, and'v in some instances a mat is placed. between. two, steel' platesjwhich. support the mat whilev the plates and mat move forwardinto the press as a unit; In all such presses i-t is desirable to have the temperature and pressure. rapidly applied and justas rapidly removed after the desired period ofl time for creation of a board of the desired characteristics; Therefore, automatic means forl feeding the matv and formed board-must be pro'- vided, particularly'in orderthata multiple platen presslmayfoperate upon a plurality ofmatssimul'- the prior pressl loadingfand unloading devices as 'heretofore describedf certain drawbacks existed which Ivvill be outlinedA below;

For example, iff a mat were sandwiched? be-A tween ltwo smooth faceplates steamA and hot water trying to escapefrom theL wet matfwoul'd be'- blockedat both of the wide surfaces:n with the result` that Wthe steamr and hot'` Water would' havey Ito escape from the narrow, outer edgesof the mat, if. at all'. Thisvvouldresult in excessive drying of" some1-areas and* continuedv softening of" I other areasv a's/waterat high temperatures, due

lto steam not being permitted to form, rushes to seek the easiest paths of'escape. Further, if

steam did '-form, itwould behighly superheated' and under terriic pressure and the bre mats- Awould be disruptedfand cracked. Further than this, the natural. ligninsl or" other binding sub-- stancesof the-libre material' and any added resin'- ous binder or the like would' be unevenly redis-A tributed throughout the libres, causing the formation of discolored spots and weak'or soft spots invarious irregular areas-f throughout the board. Also,' sugars or other .carbohydratey compoundspresent in the fibres or themixture would be'V drawn to'thesurfacesoffthe'mats and would char againstv the hot-A steel plates,A forming discolored' areas ink tlieboards and build-ing` up 1 deposits on the plates which destroy theirfusefulness as surface'lnisliing members.- In an attempt to correct this condition, a wire screen has been used as a feedingV means, the screen traveling-y forward Lover thelbottom platen of a pair of'fplatensto feed the mat into` the' pressV and" remaining in position above? the` lower platen' to provide channels for theV escape of steam and hot-water aspressure andheat are applied. Sinceat least4 one surface of a boardshouldbe smoothv when finished, thisfscreen could not be endlessly'disposed about a pla-ten but was wound upon rollers at one or both# ends of the* platen. InA some cases theA screen Wasfed'- iny one direction to feed a wet matV into the press` and fed in the opposite direction to return the-finished` board to the same'sideof; the` press'` from which the wetmat was delivered,l

thus complicating the delivery and unloading mechanism and requiring' delay inthe operation of? theentire plant. In otherinstances a long press-feeding` screen wasso arrangedy that a portion' thereof extended toward` the loading side `for reception; of a vwet mat and a portionthereof extended" beyond the opposite. side for unloading of'nished boards, the screen being fed intermittently forward rst to place the wet mats, then, in the same direction, to eject the finished board. This required a large floor area, long screens and a period of waiting while the screen was completely returned to its original position after delivery of the finished boards.

The object of my invention is to provide press loading and unloading means in which the screen is mounted upon endless chain means guided about feeding rollers at the ends of the press platens, the screen being associated with half of the chains and the space between the remaining half of the chains being open. By my invention the chain can be fed in the same direction at all times, thus simplifying the driving means therefor. The press feeding and unloading movement is accomplished simultaneously without pause between the two movements or reversal of direction of movement of the screen.

A further object of the present invention is to provide a loader and unloader for a board forming press which will operate in conjunction with an accumulator rack for wet mats.

The objects and advantages of the present invention will be more readily ascertained from inspection of the following specification taken in connection with the accompanying drawings wherein like numerals refer to like parts throughout, while the features of novelty will be more distinctly pointed out in the appended claims.

In the drawings:

Fig. l isa partial plan view of a press platen formed in accordance with my present invention;

Fig. 2 is a side view of the apparatus disclosed in Fig. l;

Fig. 3 is a vertical section, on an enlarged scale, taken substantially along line 3-3 of Fig. 2;

Fig. 4 is a schematic representation of a press formed in accordance with the present invention at the moment of receiving a wet mat fed thereto from the accumulator rack;

Fig. 5 is a similar View showing the press in the act of closing;

Fig. 6 is a similar View showing the press at the instant it commences to open after formation of the board;

Fig. 7 is a similar view showing the press in the act of feeding a board into the unloading rack;

Fig. 8 discloses a modified form of surface plate which may be employed; and

Fig. 9 discloses a further modified arrangement of surface plate with heat retarding means.

In the present disclosure a single platen is illustrated and described. It is to be appreciated that this platen is but one of a plurality of superimposed platens mounted in a press capable of opening and closing the gaps between platens substantially simultaneously, a number of such presses being well known in the art.

The platen comprises a rectangular, hollow member Iii having passages I I therethrough, through which a heating medium, preferably steam, is circulated. Other heating means may be incorporated in the platen, the sole requirement being that a rigid, smooth-surfaced body capable of sustaining its shape over the large area be heated to temperatures exceeding the boiling temperature of water. Various means may be associated with'the platen to raise and lower it vertically whereby it may be separated from or brought into pressing relationship with adjacent platens. A pair of rollers I2 andA I3 extend parallel to the ends of the platen I0,'the

rollers being mounted upon Outrigger bearings I4 4 or the like through which roller supporting shafts I5 extend. The roller I2 is provided with a pair of sprockets I6, only one of which is shown, and the roller I3 is provided with a pair of driving sprockets I1, only one of which is shown. A spiral gear I8 is fixed to the protruding end of the shaft of roller I3 and is driven by a meshing spiral gear I9 which is splined to a vertical shaft 2U extending alongside one corner of the press. The gear I9 is caused to slide vertically of the splinedshaft 20 as the platen moves by means of a pair of gear embracing arms 2| mounted upon the Outrigger bearing support I4. The shaft 2O extends into any suitable driving mechanism whereby it may be rotated to a desired extent when desired. Upon rotation of the shaft 20 each of the driving sprockets I1 is rotated to advance a pair of sprocket chains 25 extending about the sprockets I6 and II.

The upper or working ights of the sprocket chains 25 are guided upon guide bars 26 fixed to the side walls of the platens. The lower or return flight of sprocket chains 25 passes between a plurality of brackets 2l mounted upon the side wall of the platen, and the upper surface of a face plate 28 suspended from the brackets by a. plurality of studs 29 screwed into the upper surface of the plate and passing through openings in brackets 21, the studs having their heads limited against downward movement by the brackets 21. The face plate 28 is preferably formed of stainless steel or faced with a noncorrosive metal such as chromium.

A pair of crossbars 30 extend between the pair of sprocket chains, the distance therebetween being approximately half the length of the chains, and a screen 3I is stretched between the crossbars. The screen 3I is therefore slightly longer than the length of the platen, being of sufficient length to extend partially about each of the end rollers I2 and 3 when the screen overlies the platen as seen in Figs. 5 and 6. When in this position the screen serves as a porous layer through which steam and hot water extruded from the wet mat may escape to the edges of the press. After the board is consolidated and the upper platen raised therefrom the screen may be fed forwardly half the length of the chains 25, thus causing the board to be ejected from the press. At the completion of a half-length movement of the chains 25 the screen is positioned between the face plate 2B and the lower surface of the platen, the face plate 28 having dropped as seen in Fig. 2 to provide a space through which the screen may travel. The screen may be arrested in this positionuntil a succeeding wet mat commences to move into the press. Simultaneously therewith the shaft 2t may be actuated by any suitable manual or automatic control means to cause the screen to move forward half the chain length. The leading crossbar 3 therefore clears the roller I3 by the time the leading edge of the wet mat reaches the roller I3, and the screen, which is fed at a rate synchronized with the rate of movement of the wet mat, carries the wet mat into the press and is stopped when the mat is completely located between the platen and the face plate of the next upper platen.

In Fig. l the press is shown at the beginning of the feeding movement of a wet mat 35 thereinto from a plurality of rollers 35 set at an incline so that initial movement is all that is necessary to cause the wet mat to roll downvinto the press under its own momentum. The screen 3| has begun to move and the screenwill continue to feed the mat into the press until arrested as seen in Figs. and 6. The press is closed to an extent such as to apply the desired pressure uniformly throughout the area of the mat and the temperature of the platens is maintained at the desired point determined as best for the particular material and end result. When the press is opened the screen moves forward to eject the finished board onto unloading rollers 3T. It is to be appreciated that any suitable feeding means to present the wet mat to the screen 3| and any suitable unloading means to receive the finished board from the screen 3| may be associated with the present invention.

In Fig. 8 there is disclosed a modification of the face plate which may be found desirable in the formation of boards from certain types of fibre or when employing certain chemicals with the libres. It sometimes proves desirable to delay the application of heat to the upper surface of the wet mat, and for this reason heat transmission delaying means may be interposed between the face plate and the lower surface of the platen. Such means merely accomplish the reduction of the rate of heat transmission for a short period of time when the face plate first contacts the upper surface of the wet mat prior to the application of pressure upon the complete closing of the press. Fig. 8 discloses one manner in which this may be accomplished, the face plate 40 herein disclosed being provided with a plurality of parallel ribs 4|. The depth, arrangement and spacing or" the ribs 4| may be varied as conditions warrant. A similar effect may be provided with the arrangement disclosed in Fig. 9 wherein heat delaying means such as a sheet of asbestos 5! may be placed upon the upper surface of the face plate 50. The arrangement disclosed in Fig. 9 may be best, since the thickness. and other characteristics cf the sheet 5| may bevariedby merely removingone sheet and replacing itwith another.

It will be appreciated that the modifications disclosed in Figs. 8 and 9 are identical in the sense that a heat transmitting unit is suspended beneath the upper platen,y which unit is platelike in form and which comprises a lo-wer section of solid metal presenting a smooth lower surface throughout and having a high, uniform effective rate of heat conductivity, and an upper section having a uniform effective rate of heat conductivity lower than that of the lower section, the unit covering the entire surface of the platen. In Fig. 8, the lower section is the solid metal portion of the plate 40 and the upper section comprises the ridges 4| and the intervening air spaces provided by the grooves between the" ridges. In Fig. 9, the lower section is the metal face plate 50 and the upper section comprises the asbestos sheet 5I. The air spaces between the ridges Hand the asbestos sheet both retard the transmission of heat through the solid lower face plate to the upper face of the mat so as to delay the heating of the face of the plate in contact with the wet mat, just as the application of heat to the lower surface o1 the mat is delayed by the interposed screen 3|.

Having illustrated and described a preferred embodiment of my invention, it is to be appreciated by those skilled in the art that modications in detail and arrangement thereof are permissible. All such modifications as come within the true spirit and scope of the appended claims are considered to: be a part of my invention.

medium, a first roll I claim:

1. A multiple unit hot press for forming artificial boards from mats of fibers, each unit thereof comprising a rectangular press platen adapted tol be heated by an internally circulatingheating medium, a first roll mounted on and extending parallel to one end of said press platen and a second roll mounted on and extending parallel to the opposite end of the press platen, a sprocketr at each end of each roll and located beyond the side walls of the press platen, said sprockets being coaxial with and drivingly connected to their respective rolls, a sprocket chain passing about the pair of said sprockets 'at each side of said platen, a pair of spaced crossbars extending between said sprocket chains, a single screen stretched between said crcssbars, a relatively thin, heat-transmitting face plate` suspended beneath said platen, and suspension means for said face plate comprising brackets mounted upon the side walls of said platen and suspending members mounted in said brackets and movably supporting said face plate, said sprocket chains passing between the side walls of said platen and said suspending members, and the upper surface of said face plate having a plurality of closely spacedr grooves therein providing small ridge areas in contact with the lower face of said press platen when the press is closed whereby to delay the transfer of heat to the upper surface of the mat during its formation into a board.

2. A multiple unit hot press for forming artificial boards from mats of fibers, each unit thereof comprising a rectangular press platen adapted to be heated by an internally circulating heating mounted on and extending parallel yto one end of said press platen and a second roll mounted on and extending parallel to the opposite end of the press platen, a sprocket at each end of each roll. and located beyond the side Walls of the press platen, said sprockets being coaxial with and drivingly connected to their respective rolls, a sprocket chain passing about the pair of said sprockets at each side of said platen, a pair of spaced crossbars extending between said sprocket chains, a single screen stretched between said crossbars, a relatively thin, heat-transmitting face plate suspended beneath said platen, and suspension means for said face platecomprising brackets mounted upon the side walls of said platen and suspending members mounted in said brackets and movably supporting said face plate, said sprocket chains passing between the side Walls of said y platen and said suspending members, and the upper surface of said face plate having a plurality of closely spaced projections thereon which contact the lower face of said press platen when the press is closed whereby to delay the transfer of heat to the mat during its formation into a board. y

- RALPH CHAPMAN. References Cited in the file of this patent UNITEDy STATES PATENTS Number Name Date 1,005,706 Hlock Oct. 10, 1911k 1,485,894 Sutherland Mar. 4, 1924 1,536,163 Sutherland May 5, 1925 1,626,419 Mell Apr. 26, y1927 1,690,152 Ziska Nov. 6, 1928 1,737,143 Burnham Nov. 26, 1929 1,881,548 Harvey Oct. 11, 1932 1,949,917 Muench Mar. 26, 1934 Sweeney June 22, 1937

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