US 1568401 A
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Jan. 5,1926. d 1,568,401
C. R. GRIFFITH ROLL FOR CARRYING FABRIC CONVEYER BELTS OF PAPER MAKING MACHINES Filed July 18, 1923 Paume mes, 192e.
CHARLES B. GRIFFITH, 0F PORTLAND, OREGON.
BOLL FOR OABBYING FABRIC CONVEYEB BELTS OF PAPER-'MKING MACHINES.
Application tiled July 18, 1923. Serial No. 652,332.
To all whom it may concern.'
a citizen of the United States, and a resident of Portland, county of Multnomah, and State of Oregon, have invented a .certain new and useful Improvement in Rolls for Carrying Fabric Conveyer Belts of Paper- Makmg Machines, of which the following is a specification.
My invention relates to endless conveyerbelts, or the so-called felt belts, provided in paper making machines for carrying the pulp stock from the Fourdrinier wire to the presses and between the presses if there are moreithan one. These conveyer-belts are run over rolls and are kept at proper tension so as to travel with the revolution of said rolls.
The tension induced in said felt belts has a tendency to contract said felt belts in width. Said belts are of considerable length and are subjected to a substantial amount of tension and also are run at a relatively high rate of s eed. The felt is substantially the same wi th as the sheet of paper carried thereby and thus any narrowing of the felt belts by the tension to which it .is subjected will have an injurious effect upon the sheet of paper carried thereby. The tensioning of the said felt belt also causes the same to buckle longitudinally which tends to cause the sheet of paper to be correspondingly buckled and creased by the -press rolls.
Devices are commonly provided therefor to counteract said tendency of the felt belt to benarrowed and to keep it spread out flat and at its full or normal width. These means most commonly consist of rolls having left and right hand spiral ribs on their peripheries which lead towards the opposite ends of said roll. The felt belt in passing over said roll is stretchedby the lead of said spiral ribs in opposite directions and is maintained at its fulI or normal width.
Formerly some of these rolls were made from copper or bronze, While others were made of wood and had strips of canvas or felt spirall fastened thereto.
Thewoo en rolls with the attached pieces of canvas or felt of course were very unsubstantial devices, and needed frequent replacements, while the bronze rolls being nonyielding soon wore the conve er unduly. The acids in the pa er also attac the bronze or cop' er rolls an small particles of metal chip o and thus leave the metal roughened.
These rough spots wear the fabric unduly and in some instances make minute tears.
My invention consists in making said feltbelt carrying roll with a cylindrical body, preferably with its circumference encased in hard rubber, and provided with circumferential spiral ribs made of softer rubber so as to have a substantial degree of resiliency. Said spiral ribs are formed as heretofore with the left and right hand spiral ribs extending respectively towards the opposite ends of said roll. The resiliency of said spiral ribs, however, causes them to have a substantial tractive surface capable of moving the felt forward and simultaneously spreading theV same without causing the corners of said ribs to cut into and wear the felt-belt unduly.
I illustrate the details of construction and operation of my invention in the accompanying drawings, in which:
Fig. 1 is a plan view of my said improved roll as preferably constructed; p
Fig. 2 is a similar view of my roll with the circumferential elastic ribs thereof provided only at the ends of the roll.
Fig. 3 is an enlarged lon itudinal section of one end of my roll and s ows how the roll can be made with a hollow core and covered with a jacket of hard rubber provided with soft rubber circumferential ribs.
The roll a is supported on both ends by stub shafts b which are enlarged as at c and adapted to fit Within the tubular core d so as to ,provide heads therefor. The covering e is placed on the outside of the tubular core and is preferably made of hard rubber or similar material. In a paper machine this outer casing is hard vulcanized rubber which has high wearing qualities and is not affected by water or chemical ingredients of the paper. Spiral projections f are provided which are made of a more elastic material and preferably of almost pure rubber. The whole mass is then subjected to heat and the projections f and the composition surface e are vulcanized so as to constitute an integral mass, the projections f being softer and more elastic than the shell e. A roll thus made for paper making ma chinery, can have new projections vulcanized on the roll when the previous projections are worn and thus is easily kept in perfect condition. A felt-belt is tensioned to a substantial degree and thus if my roll is not placed at the end of said belt so that the normal width.
'l'elt takes a turn about the same the felt strikes said roll only at substantially a tangent thereto. The spiral ribs must be relatively soft therefor and set relatively close together so as to provide ample tractive surface, not only to move said felt-belt folav'ard, but also tol maintain the same at its full or The spiral ribs or brojections, being soft. also do not wear the feltbelt as much as similarly formed rolls in which the spiral ribs or projections are relatively non-yielding.
In rolls of the latter type, the spiral ribs must have relatively square corners so as to grip the felt-belt and said square corners, in movingr relatively transversely of the felt` wear the felt unduly. If said ribs have becollie pitted due t0 the action of the chemicale in the paper stock, said spiral ribs or projections present relatively sharp edges that tear the felt-belt, more orless, so that the life thereof is relatively short. In my invention Where the trat-tive hold is provided by relatively soft yielding rubber ribs,
the belt is thus not so severely used and its life is therefore greatly extended.
1. A felt-belt carrying roll for paper making machine, coi'nprising an inelastic cylindrical body unaffected by certain chemicals and provided at each end with a circumferential spiral rib consisting of elastic material unaffected by said chemicals, said ribs being of substantial Width and extending respectively towards the opposite ends of said roll in closely spaced turns, whereby a substantial tractive surface is provided for said belt, capable of moving the latter forward and simultaneously spreading the same, and keeping it spread, to its normal width.
Q. A felt-belt carrying roll for paper making machine. comprising a cylindrical body having its circumference encasedin hard rubber and provided at each end with a circumferential spiral rib consisting of soft rubber, said ribs being of substantial Width and extending respectively towards the opposite ends of said roll in closely spaced turns. whereby a substantial tractive, surface is provided for said belt, capable of moving the latterforward and simultaneously spreading the same, and keeping it spread, to its normal Width.
3. felt-belt carrying roll for paper making machine, comprising a cylindrical body having its circumference encased in hard rubber and provided at each end With a circumferential spiral rib consisting of soft rubber, said ribs beginning approximately at the longitudinal middle of said body, be,
ing of substantial width and extending respectively towards the opposite ends of said roll in closely spaced turns, whereby a substantial tractive surface is provided for said belt, capable of moving the latter forward and simultaneously spreading the same, and keeping it spread, to its normal Width.
CHARLES R. GRIFFITH.