US2599693A - Press loader and shutter - Google Patents

Description

June 10, 1952 R. CHAPMAN PRESS LOADER AND SHUTTER 5 Sheets-Sheet 1 Filed April 10, 1948 I l INVENTOR.

pk Chapman June 10, 1952 CHAPMAN 2,599,693

PRESS LOADER AND SHUTTER Filed April 10, 1948 5 Sheets-Sheet 2 v INVENTOR. Ralph Chapman June 10, 1952 R. CHAPMAN PRESS LOADER AND SHUTTER 5 Sheets-Sheet 3 Filed April 10, 1948 INVENTOR. Pg /,0// Chapman d /WW fl/fa rr/E/ June 10, 1952 R. CHAPMAN PRESS LOADER AND SHUTTER 5 Sheets-Sheet 4 Filed April 10, 1948 June 10, 1952 CHAPMAN 2,599,693

PRESS LOADER AND SHUTTER Filed April 10, 1948 5 Sheets $heet 5 Fji I /Z6//U /ZZ '-z-' 75' /27 /2/ 2 4 24 f7 INVENTOR. A33 Ralph Chapman Patented June 10, 1952 PRESS LOADER AND SHUTTER Ralph Chapman, Corvallis, Oreg., assignor to Chapman Forest Utilization, Ina, Corvallis, 0reg., a corporation of Oregon Application April 10, 1948, Serial No. 20,335

10 Claims.

My present invention comprises a press loading device for a fibre board machine whereby automatic production of artificial boards at high speed is accomplished.

In the art of forming fibre boards a wet mat of fibre formed from wood, straw, waste paper, or other cellulosic material, with or without added binding substances such as phenolic resins, may be inserted between platens of a press capable of compressing and heating the mats to form a con solidated board from the loose fibre mat. Production of such mats is accomplished on a variety of machines such as the Fourdrinier type, the cylinder type, or the deckle box type machine, in all instances the fibre being deposited upon a screen or the like by the application of suction to the opposite side of the screen to withdraw water from a thin slurry of fibre. After formation of thev wet mat it is usually squeezed or otherwise compressed at lower temperatures to express most of the free water from between the fibres so as to create a tangled mat of fibres at about 50% saturation. After such operation the mat is 001m pressed and heated to varying extents to create artificial boards of various densities and thicknesses. The present invention is concerned with the final step of heating and compressing the partially wet mat.

A serious problem in the manufacture of artificial boards is the loading and unloading of the heating press. The mat, for the formation of a board having a density of one and a thickness of approximately 4 inch, may be as much as two inches thick after it has been released from the cold press and the fibres have sprung back as much as their character will permit. Usually such boards are made in commercial sizes, such as 4' x 8, so that the mat is easily disrupted. In order to heat and press the wet mat properly a period of time ranging" from five to twenty-five minutes is usually allowed, on the average about fifteen minutes. Mats can be formed faster than one every fifteen minutes so multiple platen heating presses have been developed, each capable of holding, for example, twenty wet mats and simultaneously consolidating them into boards. Therefore, if the consolidating operation requires twenty minutes, a twenty unit press can keep up with the output of a forming machine capable of creating one mat every minute. The diificulty. however, has been to load the mats into the forming press at a speed commensurate with the ability of the consolidating machine. The principal object of my present invention is to provide means for loading mats into a consolidating press iii 2 as fast as they can be formed by the forming machine without endangering the wet mats while they are being handled.

With my invention mats can be formed at the rate of one every thirty or forty seconds and loaded into a consolidating press operating on fifteen to twenty minute cycles without necessarily interrupting the forming operation.

An object of the present invention is to provide means to store wet mats as they are formed in an accumulator rack positioned between the mat forming machine and the consolidating press, such accumulator rack being so constructed and arranged as to receive mats at spaced intervals from the forming machine and position them opposite the platens of the consolidating press.

A further object of the present invention is to provide means automatically to control the operation of the accumulator rack whereby a plurality of storage trays or the like are presented successively at the level of the forming screen and into which the mats are fed during intermittent movements of the forming screen.

A further object of the present invention is to provide means automatically to deliver a plurality of wet mats stored in the accumulator rack simultaneously into the consolidating press.

A further object of the present invention is to provide means to protect wet mats stored in the accumulator rack adjacent the press from the effect of heat radiated from, and steam escaping from, the consolidating press. It is desirable to subject all areas of a wet mat to the same conditions at all times and a drawback in the use of accumulator racks has been that the ends of mats adjacent the consolidating press have been subjected to drying heat and steam prior to the subjection of the remainder of the mat thereto. My invention provides automatically operating shielding means to prevent radiation and steam from the consolidating press from reaching wet mats in the accumulator rack.

The foregoing. and other objects and advantages of the present invention will be more readily ascertained by inspection of the following specifications taken in connection with the accompanying drawings wherein like numerals refer to like parts throughout while the features of novelty will be more distinctly pointedout in the appended claims.

In the drawings:

Fig. 1 is a vertical section through a portion of a board manufacturing plant taken at one side of the accumulator rack and showing the relation thereto of the board forming equipment and the consolidating press;

Fig. 2 is a plan view on an enlarged scale of the accumulator rack of the present invention;

Fig. 3 is a detail View on an enlarged scale taken substantially along line 33 of Fig. 1;

Fig. 4 is a horizontal section on an enlarged scale taken along line 4-4 of Fig. 1;

Fig. 5 is a vertical section on an enlarged scale taken substantially along 1ine 5-5 of Fig. 2;

Fig. 6 is a vertical section taken substantially along line B6 of Fig. 1;

Fig. '7 is an end view of the pusher illustrated in Fig. 6;

Fig. 8 is a vertical section on an enlarged scale taken substantially along line 8--8 of Fig. 2;

Fig. 9 is a vertical section on an enlarged scale taken substantially along line 9-9 of Fig. 1;

Fig. 10 is a sectional view taken substantially along line 10-40 of Fig. 9;

Fig. 11 is a vertical section taken along line ll-H of Fig. i;

Fig. 12 is a vertical section taken along line 12-42 of Fig. 11;

Fig. 13 is a schematic representation showing Fig. 16 is a similar view showing the operation of the pusher to start wet mats into the consolidating press;

Fig. 17 shows the completion of the movement of the mats into the consolidating press;

Fig. 18 is a similar view showing the arrangement of the consolidating press with respect to the accumulator rack of the present invention and an unloading mechanism at the far end of the press;

Fig. 19 is a schematic view showing a portion of a control device;

Fig. 20 is a similar vlew showing another portion of the control device; and

Fig. 21 is a. schematic representation of a control circuit embodied in the present device.

Although many different types of intermittently movable mat forming machines may be associated with the present invention, reference is hereby made to my copending application, Ser. No. 20,334, filed concurrently herewith, in which such a machine is illustrated and claimed. For the present invention it is sufficient to set forth that wet mats are fed forwardly by an intermittently movable conveyor or forming screen having a working flight 20 and a return flight 2!, the conveyor passing about a feeding drum 22 mounted on a shaft 23 near the end of a frame 24. The frame 24 extends beyond the drum 22 and is provided with a plurality of idler rolls 26 spaced closely together so as to support the wet mat when moved forwardly thereover by the screen or conveyor which remains in contact with the rearward portion of the wet mat until all of the mat has passed beyond the drum 22. Intermittent movement of the conveyor may be accomplished by any suitable automatic or manual control means as set forth in the foregoing application.

The frame 24 overhangs a pit 30 of substantial size and depth extending beneath the level of thereof adjacent the forming machine.

the feeding flight 20. An accumulator rack is vertically guided for movement from and into the pit 33 by four guide posts 31 suitably mounted within the pit and maintained in spaced relationship by a bottom frame 32 and a top frame 33 located at a considerable height above the level of the working flight 20. A suitable form of post for the purpose is herein illustrated, the same comprising a length of steel or cast iron pipe of large diameter such as six to eight inches. The accumulator rack 34 comprises a lower frame 35, an upper frame 36 and vertical side members 31, 38, 39 and 40. The distance between the upper and lower frames is such that a plurality of roller trays 4! corresponding in number to the number of platen spaces of the consolidating press to be served may be located therebetween as shown in Fig. 1. In order to guide the accumulator rack 34 in its movement each upper and lower corner thereof is provided with a guide bracket 42, a part of which comprises a horizontal plate having a substantially semi-circular notch 43 therein of substantially the same diameter as the tubular guide post. The plate projects forwardly in position to embrace the post 3| with the outer surface thereof received in the notch 43. Each of the notches 43 has a plurality of smaller notches 44 therein which prevent the plate from scraping lubricant entirely toward the top and bottom of the posts. There will always be some lubricant distributed along the posts in vertical streaks as permitted by the small notches 44.

Each roller tray 41, as is clearly seen in Figs. 9 to 12, inclusive, comprises a side channel member 45 between which are mounted a plurality of closely spaced rollers 46 extending transversely of the tray. As seen in Fig. 3, the rollers 46 each comprise a length of light weight metal tubing, into the open ends of which are pressed the outer raceways 41 of ball bearing assemblies. the inner raceways 48 thereof being mounted upon the reduced inner ends of threaded studs 49 passing through nuts 50 welded to the member 45 and retained in adjusted position by lock nuts 5| as shown. Each of the rollers 45, therefore, turns very freely with a minimum amount of frictional resistance. As seen most clearly in Fig. l, the trays 4! are arranged at a slight incline extending downwardly from the ends Therefore, as seen in Figs. 13 and 14, when a. wet. mat is fed forwardly onto one of the trays and its rear end has passed beyond the end of the working flight 20, the mat will proceed completely into the accumulator rack due to its own m0- mentum.

At the far end of the rack there is provided a shutter comprising inwardly facing fixed channel members extending horizontally across the space between the upright members 49. The top of each channel member is at or slightly below the level of the last roller 46 and the bottom thereof is spaced above the next lower set of rollers to leave a gap wide enough to permit free passage of the thickest mat formed. The channel members 60 constitute fixed vanes or members forming a partial screen across the far end of the accumulator rack for partially shielding the ends of wet mats thereon from the consolidating press indicated at 6 I Movable vanes cooperatin with the fixed vanes may be moved to closed position to create an imperforate wall or shield between the consolidating press and the wet mats, such movable vanes, preferably comprising. facing channel bars. 62 ofsubstantially thezsame: size as the: channel bars 00. The ends of bars 62 extend beyond the. ends of bars 00,. as. seen in;Figs. 9. and 11, and are mounted upon a. pair of slides preferably comprising lengths of tube 63, slidably mounted upon vertical guide rods. 84. extending between the frames 35 and 36:. The tubes 03 are shorter than. the rods I34 and. both ends of each rod 04 project beyond the tube 63. The lower end of rod 64. is provided with a transverse crosshead 65 receivable between the arms of a short channel member 65 having open jaws at one side. Crossheads 55 are preferably hollow and internally threaded in order that studs TI may be received therein to clamp the lower end of the rod in position. The upper end of each rod. is threaded and received in an internally threaded capstan member 68 which is rotatably mounted in a bracket 89 suspended from a corner of the upper frame 35. The capstan member 68 may be. turned to adjust the tension of rod 64.

Inorder to control the relative position of the fixed and movable vanes the lower end of the tube 63 has welded thereto an extension rod "I0 which passes through holes in the lower frame 35, the rod being of such length as to strike a fixed abutment such as the floor of the pit 30 shortly before the rack reaches its lower limit of movement. control of the descending movement of the rack iscoupled with the upward movement of the movable. vanes as accomplished by the extension 10 so that when the movable vanes bridge the gaps. between the fixed vanes, therack will come 7' to. rest. Such means are not herein disclosed as behig obviously within the skill of the ordinary person skilled in the art. The upper end of one of the. tube 63 is provided with a laterally extending bracket I in which i mounted a transverse keeper I6 capable of being received in the hook of a latch 11 pivotally mounted upon the bracket 68 and having a cam face at its lower extremity. The latch 11 comprises a bell crank,

the crank arm of which is pivotally connected to. the upper end of an armature 79 forming a movable core. for a solenoid 80 mounted upon a bracket extension of the frame 35. The lower end of armature 19 has a limiting enlargement BI thereon to prevent the armature from passing upwardly through the solenoid beyond a limited extent, and a weight 82 may be attached thereto to assure its descent when the solenoid is deenergized. Upon upward movement of the tube 63, the keeper 16 strikes the cam face It and rocks the latch TI outwardly until the latch is free: to snap back and hold the movable vanes in elevated position. The movable vanes will be held in closed. position until solenoid S0 is energized to release. thelatch whereupon the movable vanes will drop until arranged opposite. the fixed vanes. When the movable vanes are in screening position they form stops against which the wet mats come to rest after being fed into the accumulator rack.

The rack. is intermittently moved upward the distance. between trays between each intermittent movement of the forming machine conveyor until the rack reaches the upper limit of its movement and isunloaded, whereupon it is rapidly returned to its. lower position as seen in Fig. 1. Movement of the rack is accomplished by the following mechanism.

A motor 83 is mounted upon the top frame 33 and belt-connected to the shaft of a reduction Means may be provided whereby gear mechanism. 85-. The. shaft; 86. from the mechanism 85 is fixed to the driven member-of any suitable clutch 81, the, driven. member of which is splined: to; a. stub shaft 88 supported transversely of the center of the frame in. journals 89.. A pair of sprockets 90- are fixed to the shaft 88 between the journals 89. The movable element of clutch 81. is fastened to a shifting collar 9| which is embraced between the arms of a.yoke lever 92' pivotally-mounted upon a bracket 93 extending from one of the journal supports. The lower end of yoke lever 92 is connected to the armature 84 of a solenoid 95. Upon energization of solenoid S5 the lever 92 is rocked to engage the clutch and vice versa. Details of the clutch are not given since many such devices are readily procurable. Each of the sprockets 90 drives a sprocket chain 91 which extends toward one end of the frame and passes about a sprocket 98 fixed to a shaft 99 journaled on the top of the frame. The outer ends of each shaft 99 support sprockets I00 about which pass elevator sprocket chains IOI having three supporting lengths. One end of the chain I M is fastened to the frame 33. The chain then passes downwardly about an idler sprocket I02 mounted at a corner of the accumulator rack frame 36, then upwardly about the sprocket I00, then downwardly into the supporting column 3I and i attached to a heavy weight I04 slidably guided therein. The four weights I04 counterbalance the accumulator rack to some extent but their main function is to keep the chains I M taut. Movement of sprockets I00 counterclockwise is simultaneously accomplished by operating motor 03 when shaft 86 is clutched to stub shaft 88, thereby elevating the accumulator rack 34. Releasing the clutch will permit the rack to drop rapidly to the bottom of the pit.

Schematic means are set forth in Figs. 19, 20 and 21 for controlling the motor 83 and the clutch 81. At the far end of the overhanging portion of frame 24 there is provided a cross shaft I07 which extends parallel to the rollers 26. An intermediate portion of the shaft I01. carries a sensing plate I09 which projects upwardly into the path of the wet mats 55. The shaft I01 has a movable contact arm I08 thereon which is engageable with a fixed contact H0. The shaft I0! is lightly weighted as by means of an eccentric weight I I I which exerts counterclockwise force tending to keep the contacts I09 and H0 engaged until released by the mat 55 rocking the plate I09 forward. The eccentricity of weight III is such that the sensing plate will be rocked back to its projecting position as soon as the end of the mat 55 passes beyond the plate. A collar I I2 loosely surrounds a portion of shaft I01 and is eccentrically weighted as by an arm II3 so positioned as to pass beyond the vertical toward each side. The shaft I01 has a stud H4 projecting therefrom which is engageable beneath a pin I I 5 on collar I I2. The collar I I2 also carries a contact arm H6 which is engageable with a fixed contact II! when the weight H3 is thrown clockwise beyond the vertical by rotation of shaft I01 due to the depression of sensing plate I09. The weight II3 will hold the contacts IIS and II? closed even though shaft I01 reverses when contact plate I09 is released from the mat 55. The projecting end of contact arm IIG extends sufficiently when rocked forward to be engaged by a series of lugs II8 projecting from the frame member 37 and spaced apart corresponding to the spacing of the rack roller shelves.

The control circuit embodies a motor controlling line I in which the two sets of switch contacts I08I Ill and IIfi-I I1 are placed in series. When a mat is moved forward from the forming machine or conveyor, the sensing plate I09 is rocked to move contact I88 from contact II 0, thus breaking the circuit to motor 83. This is instantaneously succeeded by contact I It being moved into engagement with fixed contact III, but the circuit to motor 83 remains broken until the mat is almost entirely into the accumulator rack and sensing plate I09 is released. Motor 83 is now energized to move the rack slowly upward. One of the lugs II8 soon contacts the outer end of arm IIG to break the circuit to the motor and thereby bring the rack to rest, the lug II8 being so placed that the next lower, empty,

roller tray will be in position to receive the succeeding mat.

The solenoid 95 is controlled by a switch I2I in a line I22, the switch being moved to its open position by means (not shown) actuated when the press is filled. The switch |2I is normally closed so that the clutch normally remains engaged, thus holding the rack at the positions to which it is moved intermittently by the motor 83. The weight of the rack varies as the successive mats are loaded therein and the clutch is the sole means for preventing the rack from returning to the bottom of the pit. The reduction drive from the motorcauses relative slow upward movement of the rack at each step, but

if the clutch is disengaged the rack will drop rapidly to the bottom of the pit. In order to arrest the rack at the bottom of its movement the switch I2I is opened by means (not shown) associated with the rack, whereupon the clutch is engaged and the successive operations of the motor will thereafter cause intermittent upward movement. In order that the rack may be returned at any time a manual switch I23 is positioned in a jumper circuit I24 whereby the clutch may be disengaged independently of the opera- .1

When the filled rack has been arrested at its uppermost position and the movable shutter vanes dropped, the mats will remain in the accumulator rack since the incline of the roller trays is not great enough to permit the mats to move forwardly, at least without an initial im petus having been given to the mats.

The pusher comprises a frame including a pair of vertical channel bars 130 depending from a pair of slightly inclined channel bars I EI arranged parallel to the inclined roller trays. The bars I3I extend beyond the bars 13% and are braced by angularly extending bars I32. A plurality of pusher rods I33 extend inwardly in vertically spaced pairs, each pair being aligned with the space between adjacent roller tray when the rack is resting at its uppermost position. A pusher plate I 34 is bent around and fastened to the inner ends of each pair of arms I33 to present a wide fiat surface adjacent the rear end of each of the wet mats resting on the roller trays. Bars I3I extend inwardly beneath the upper frame 33 and are so formed as to constitute toothed racks as, for example, by having long, toothed members I35 welded to the lower surfaces thereof. A guide member I31 is welded 8 to the upper surface and similar guide members are welded at each end of the toothed member I35 on the lower surface. A plurality of spaced pairs of supporting channel bars I depend from portions of the frame 33 and journal transverse idler shafts, a plurality of such shafts being located above the rack bar I3I and a plurality below. The upper row supports a plurality of flanged guide wheels I4I shaped to receive the guide bars I31. The outer pair of lower shafts I3I support similar guide wheels to engage the guide bar sections on the lower flange of the rack bar. A pair of angle bars I43 extend transversely between the lower ends of the intermediate pair of supporting bars to provide a support for a motor I44 which is connected to a transverse shaft I45 extending between the opposed supports and keyed to both of a pair of gears I42 engaging the rack bars so that they may be moved simultaneously and co-extensively by the motor I44. When the rack is at the top of its movement, motor I44 may be driven for a short period in a direction to throw the rack bars I3I inwardly and thereupon reversed to position the pusher plates I34 beyond the rack as seen in Fig. l. A slight movement is all that is necessary to overcome the inertia of the wet mats and cause them to commence moving outwardly through the openings in the shutter when the movable vanes have been moved to open position. Any suitable manual or automatic means may be provided for accomplishing such movement of the rack bar motor provided the movement is prevented unless the platens of the consolidating press have been opened to permit reception of the wet mats. A switch I21 in lin I22 is held open by suitable means (not shown) to prevent release of the clutch until the mats have left the rack. The extent of movement of the pusher is illustrated in Figs. 18 and 17.

In order to ensure complete withdrawal of the wet mats from the accumulator rack and insertion thereof into the platens, suitable means may be provided to engage the leading edge of each mat and draw it into the press. Such means may be formed as illustrated, described and claimed in my copending application, Ser. No. 20,336, filed concurrently herewith. For the purpose of this application Figs. 13 to 18, inclusive, illustrate so much of the press as is necessary for an understanding of the present invention. In Fig. 13 it is seen that the platens I have been moved to closed position in which pressure and heat is being applied to compress and consolidate the mats into boards. Each platen preferably has associated therewith a pair of sprockets I5! at each end, about each pair of which is extended a platen feeding chain I52. When the platens are closed or moving to closed or open position, the chains I52 are at rest and a screen or other traveling member is positioned between the opposite chains, at least between the lower platen and the wet mat or consolidated board lying thereon. In Fig. 15 the rack has been almost filled and is going up to its last position or nearly so. Time has been allowed for complete treatment of the material in the consolidating press, and the platens are moving to open position, being caused to do so by means well known in the art. In Fig. 16, the rack has come to rest at its uppermost position and the movabl vanes have dropped to open the shutter, the platens are fully open, and the pusher is commencing to move into the accumulator rack. In Fig. 17 the pusher has reached its innermost position and is commencing to move outwardly while the mat-55 continues to move from the accumulator rack into the press partly due to its inertia of movement and partly due to the forward pull thereon of the screen or other member lying between the chains 152, which has been caused to move forwardly in synchronism with the moving wet mat as detailed in the copending application mentioned above. In Fig. 18, the chains 52 have come to rest with the mat in position to be compressed between the platens, and the accumulator rack has been lowered to its lower position thereby causing the shutter to become closed. Also this figure illustrates a portion of an unloader racl: positioned at the opposite side of the press, details of which are illustrated, described and claimed in my copending application, Ser. No. 20,337, filed con,- currently herewith. In this application it is sufficient to state that an unloader rack having a plurality of trays l!) (Fig. 18) is so positioned as to receive the formed boards from the press as fully set forth in said application, Ser. No. 20,337. A plurality of fixed vanes IE1 forming a part of a shutter and a plurality of movable vanes I62 span the gaps therebetween when the press is operating as seen in Fig. 17.

Having illustrated and described a particular embodiment of my invention I claim as my invention all modifications and arrangements as come within the true spirit and scope of the appended claims.

I claim:

1. -A fibre board machine comprising intermittently movable feeding means on which wet mats of fibre may be supported and fed forwardly, a vertically and intermittently movable accumulator rack at the forward end of said feeding means for receiving said mats and holding them for subsequent insertion into an adjacent hot press, said accumulator rack including a plurality of superimposed trays each adapted to receive and hold an individual mat fed thereonto from said means, and a shutter mounted on the forward end of said rack including a plurality of parallel, spaced apart, stationary slats and a plurality of other slats movable from alignment with said stationary slats to bridge the gaps between said stationary slats whereby mats in said rack may be protected against steam and hot water issuing from said press.

2. A fibre board machine comprising mat feeding means on which wet mats of fibre may be-fed forwardly, an accumulator rack at the forward end of said feeding means for receiving said mats and holding them for subsequent insertion into an adjacent hot press, said accumulator rack including a plurality of superimposed trays each adapted to receive and hold an individual mat fed thereonto from said mat feeding means, and a shutter mounted on the forward end of said rack including a plurality of fixed slats extending horizontally and spaced apart to define a 'horizontal gap at the forward end of each tray and a plurality of intercomiected, vertically movable slats adapted to move from and to open positions aligned with said fixed slats and shut positions bridging the gaps between said fixed slats whereby mats in said rack may be protected against steam and hot water issuing from said press.

3. A fibre board machine comprising a conveyor movable intermittently at regular intervals and on which wet mats of fibre may be supported and moved forwardly, an accumulator rack at the forward end of said conveyor including a plurality of superimposed trays each adapted to receive and hold an individual mat fed thereonto from said conveyor, 2. shuttermounted on the forward end of said rack including a plurality of horizontally extending, immovable slats defining a slot atthe forward end of each tray and movable slats adapted to move from and to open positions aligned with said fixed slats and shut positions bridging the slots between said fixed slats, means intermittently to-move said-rack yer..- tically in short steps in one direction whereby each tray may receive a mat from said conveyor, means to move said rack back to its starting point in one continuous movement, means to moveisaid movable slats to shut positions upon return of said rack, means to move said movable slats to open positions following the last step movement of said rack in said one direction whereby allof said trays may be emptied, and means to eject all of the mats from said trays simultaneously when said slats have been moved to open posi: tlons.

4. A fibre board machine comprising a conveyor movable-intermittentlyat regular intervals and on-which wet matsof fibre may be supported and moved, an accumulator rack at the forward end of said conveyor including a plurality of superimposed trays each adapted to receive and hold an individual mat fed thereonto from said conveyor, a shutter mounted on the forward end of said rack including a plurality of fixed slats positioned to provide openings at the forward end of said trays and movable slats adapted to move from and to 'open positions aligned with said fixed slats and shut positions bridging the openings between said fixed slats, means inter.- mittently to' move said rack vertically -.shor.t steps in one direction whereby each atray may receive a mat from .said conveyor, means to-move said rack back to its starting point in one con.- tinuous movement, means to move said movable slats to shut-positions upon return of said rack, means to move said slats to open positions following the last step movement of said rack in said one direction whereby all of said trays may .abe emptied, and means to eject all of the mats from said trays simultaneously when said slats have been movedto open positions, said ejecting means and rack returning means being operable .successively and completely in an interval between successive movements of said conveyor.

5. A fibre board machine comprising a conveyor on which mats of fibre may be placed and fed forwardly, a vertically movable xaccumulator rack at the forward end of said conveyor for receiving said mats and holding them for subsequent insertion-into an adjacent hot press, said accumulator rack including a plurality of superimposed trays each adapted to receive and hold an individual mat fed thereonto from said con.- veyor, and a shutter mounted on the forwardend of said rack including a plurality of relatively movable members forming a wall at the ends of said trays when in one relative position and forming an open grid to provide openings through which the mats may proceed into said press when in another relative position, said members when in wall-forming relation providing stops to arrestmove said movable grid to gap closing position upon descent of said rack to its lower limit position.

7. A fibre board machine comprising a conveyor on which wet mats of fibre may be fed forwardly, a vertically movable accumulator rack at the forward end of said conveyor including a plurality of superimposed trays each adapted to receive and hold an individual mat fed thereonto from said conveyor, and a shutter mounted on the forward end of said rack including a fixed grid of slats so positioned as to provide gaps aligned with said trays and a movable grid of slats each of sufiicient width to bridge a gap between adjacent slats of said fixed grid, the slats of said fixed and movable grids being in sliding contact with each other to form an imperforate wall when in one relative position, means to reciprocate said rack between upper and lower limit positions, means to move said movable grid to gap closing position upon descent of said rack to its lower limit position, a latch to hold said movable grid in gap closing position as said rack is being elevated, and a solenoid to release said latch.

8. The combination in a fibre board forming machine of a conveyor upon which wet mats of fibre may be intermittently moved forwardly, a vertically movable accumulator rack at the end of said conveyor, said rack including a plurality of vertically spaced mat-receiving means, means to elevate said rack intermittently in short steps to position each of said mat-receiving means opposite the end of said conveyor between successive movements of said conveyor, and means to control said elevating means including a sensing plate positioned in the path of said wet mats, a first switch movable in unison with said sensing plate to an open position when said sensing plate is deflected by a wet mat and to a closed position when the wet mat passes beyond said sensing plate, and a second switch in series with said first switch and movable in unison with said sensin plate in one direction only as said sensing plate is deflected by a wet mat.

9. The combination in a fibre board forming machine of a conveyor upon which wet mats of fibre may be intermittently moved forwardly, a vertically movable accumulator rack at the end of said conveyor, said rack including a plurality of vertically spaced mat-receiving means, means to elevate said rack intermittently in short steps to position each of said mat-receiving means opposite the end of said conveyor between successive movements of said conveyor, and means to control said elevating means including a movable sensing member normally positioned in the path of said wet mats, a first control switch broken by said sensing member when moved by a wet mat, means to return said first switch to closed position when said mat passes beyond said sensing member, a second switch in series with said first switch and interconnected in one direction of movement with said sensing member to be moved to closed position when said sensing member is moved by a wet mat, and means on said accumulator rack for breaking said second switch upon completion of an upward movement of the desired extent.

10. The combination in a fibre board forming machine of a conveyor upon which wet mats of fibre may be intermittently moved forwardly, a vertically movable accumulator rack at the end of said conveyor. said rack including a plurality of vertically spaced mat-receiving means, means to elevate said rack intermittently in short steps to position each of said mat-receiving means opposite the end of said conveyor between successive movements of said conveyor, and means to control said elevating means including a sensing member positioned in the path of said wet mats, a first control switch including a contact moved to open position by said sensing member when moved by a wet mat, means to return said contact to closed position when said mat passes beyond said sensing member, a second switch in series with said first switch and including a second movable contact interconnected in one direction of movement with said sensing member to be moved to closed position when said sensing memher is moved by a wet mat, and means on said accumulator for breaking said second switch upon completion of an upward movement of the desired extent, said means to break said second switch comprising a plurality of lugs on said elevator rack spaced apart corresponding to the spacing of said mat-receiving means.

- RALPH CHAPMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,776,201 St. Clair Sept. 16, 1930 1,903,102 Farley Mar. 28, 1933 2,011,440 Dorn Aug. 13, 1935 2,171,922 Duval Sept. 5, 1939 2,200,708 Towne May 14, 1940 2,264,125 Wolf Nov. 25, 1941 2,420,813 Camerota May 20, 1947 FOREIGN PATENTS Number Country Date 433,778 Great Britain Aug. 15, 1935

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