US444862A - Pulp sceeen for papee mills - Google Patents

Description

(No Model.) 4 Sheets-Sheet 1.

P. R. THOM.

PULP SCREEN-FOR PAPER MILL$.

Patented Jan. 20, 1891.

I a'wuambo a I Pi/ &r 12/. 171 /0210. How 1,24 g p (No Model.) r 4 Sheets-Sheet 2. P. R. THOM. PULP SCREEN FOR PAPER MILLS.

No. 444,862. Patented Jan. 20., 1891.

P. R. T'HOM.v PULP SCREEN FOR PAPER MILLS.

No. 444,862. Patented Jan. 20, 1891.

(No Model.) 4 Sheets-$11961; 4.

P. R. THOM. PULP SCREEN FOR PAPER MILLS.

No. 444,862 1 Patented Jan. 20, 189.1.

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PETER R. THOM, OF APPLETON, VISOONSIN.

PU LP-SCREEN FOR PAPER-MILLS.

SPECIFICATION forming part of Letters Patent No. 444,862, dated January 20, 1891. g

' Application filed February 12, 1890- Serial No. 340,180. (No model.) i

To all whom it may concern.-

Be it known that 1, PETER R. THOM, a citizen of the United States of America, residing at Appleton, in the county of Outagamie, in the State of lVisconsin, have invented certain new and useful Improvements in Pulp-Screens for Paper-Mills, of which the following is a specification.

After paper has been properly thinned in the mixing-box it is run over screens and strained through into a vat or vats beneath,in order that impurities, lumps, shreds, and sand, or anything which would injure the quality of the paper may be removed. From the vat it 1s drawn off and taken to the wire.

It has been found desirable in the use of pulp-screens to impart to such screens a vertlcal reciprocation, whereby in the upward movement there is caused a certain suction upon the pulp overlying the screen, and in the downward movement a sort of perfiation by which the slits in the screen-plates are cleared of shreds and lumps and the pulp lightened up above themfor the next upward reciprocation. It has been attempted to obtam such vertical movement by the use of eccentrics or of rockshafts having cranks projecting horizontally, or thereabout, at the normal. Whenever an eccentric is used it must be revolved at a high speed to give the proper vibrations. Whenever a rockshaft with its cranks spread horizontally is used, it can give but a single complete up-and-down movement for each oscillation.

The object of my present invention is to keep the screen permanently in a level position'and impart to it a strictly vertical movement, improving the suction and obviating noise, besides obtaining a greater capacity and much cleaner stock, avoiding the strings andlumpsthatwerefrequentlypassedthrough by the old machine, and lessening the wear and tear due to the horizontal movement in such machine. To this end 1 mount the screens in boxes which slide in vertical guideways, and raise them by means of a link movement applied at the center of each side of the screen, as will be hereinafter described.

In the drawings, Figure 1 represents in side elevation a single screen having my improvement applied thereto. Fig. 2 is a side elevation of a double screen constructed according to my invention; Fig. 3, a top plan view of said screen; Fig. 4, an end elevation thereof.

A represents a metal supporting-frame for the superposed vat B, above which is placed the screen C, provided with screen-plates O, as usual in this class of machines. One or more vertical guide-brackets D are strongly bolted to the sides of the vat and receive closely-fitting boxes d, in which short pintles from the screen are supported. These boxes rest upon springs 61, of rubber or of any suitable construction, and are permitted an upand-down movement within their guides of about one-eighth of an inch, carrying the screen with them, but entirely preventing it from endwise movement.

Mounted in bearings E, near the foot of the 1 frame and centrally beneath the screen, is a transverse shaft F, having at each end two vertical crank-arms F, in line with each other, of exactly the same length and vibratin g to each side of the vertical. These crankarms have wrist-pins f, which support links G, also of equal lengths, the upper ends being strapped to outsetting journals 9, secured to the sides of the screen at the exact longitudinal center thereof.

Now it will be obvious that if the rock-shaft be oscillated a toggle movement will be produced between the cranks and the links, which will result in alternately raising and lowering the screen in an exact vertical line twice to each oscillation of the rock-shaft, since the crank-arms will pass the dead-center in their to and fro movement each time that the shaft has a full oscillation. There fore to one end of the rock -shaft is secured an arm H, having a wrist-pin h at its upper end, which by means of connecting-rod J is coupled with a wrist-pin upon the disk K, carried by the driving-shaft L. This drivingshaft of course will be mounted in suitable bearings, and for that purpose is shown as provided with journals Z; but the bearings themselves have been omitted as unn ecessary to an understanding of this invention. Power may be applied to this driving-shaft by means of a pulley M, or by any other suitable means. It will be evident now that when power is so applied the rock-shaft at the foot of the frame will be moved and the links alternately raised and lowered equally at each end of the machine, carrying the screen up and down. In such movement of the screen the elastic seats to its boxes will prevent any wear, shock, or noise, While the guide-brackets .will prevent endwise movement and will keep it perfectly level and true.

hen it is desired to operate two screens at once, each will be mounted upon links borne by cranks and transverse rock-shafts precisely as in the before-recited manner, and as indicated in Figs. 2, 3, and 4 of the drawings. The cranks, however,beneath the screen will be connected by a coupling rod orbar N, and an additional transverse rock-shaft 0 will be mounted in bearings 0 and on the same level as the bearings of the other shaft, and to one end of this rock-shaft Will be fixed the before-mentioned actuating-arm. This actuating-arm Will be connected by a wrist-pin p, or by an intermediate crank P and Wrist-pin p with the barwhich couples the operatingcranks beneath the screens, While the upper end of the actuating-arm will, as before, be coupled by a connecting-rod with the disk upon the driving-shaft, so that when the act-uat-iug-arm is moved motion Will be imparted to both screens at once.

I claim as my invention 1. The combination, substantially as hereinbefore set forth, of the vat, the pulp-screen, vertical guides for said screen at each side thereof and near its ends, a transverse rockshaft centrally beneath the screen and provided with vertical crank-arms at each side of the frame vibrating to each side of the vertical, or, in other words, departing from the dead-center to the right and left, links connecting said cranks to journals from the center of the screen, and means for oscillating said rock-shaft.

2. The combination, substantially as hereinbefore set forth, of the vat, two or more screens mounted therein, vertical guides for said screens at each side thereof, transverse rock-shafts centrally beneath each screen, provided with crank-arms at each end, a rod connecting the cranks of each rock-shaft at one side of the supporting-frame, links connecting each crank with the center of the respective screens, and means for reciprocating said rod.

3. The combination, substantially as hereinbefore set forth, of the vat, the superposed screen, the vertical guide-brackets, the elastic cushions therein, and the boxes sliding in said guide-brackets and carrying the screen.

4:. The combination, substantially as hereinbefore set forth, ofthe vat, the screen, the vertical guides at each side of the screen, the transverse rock-shaft centrally beneath the screen, the crank at each end of the rockshaft, the links connecting said cranks with journals from the center of the screen, the.

actuating-arm fixed to said rock-shaft, the driving-shaft and its disk, and the connecting-rod coupling a Wrist-pin upon said disk with a wrist-pin upon the upper end of the actuating-arm. r

PETER R. THOM. lVitnesses:

H. S. HOLBROOK,

O. E. CLARK.

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