US3051031A - Web cutter between tandem-arranged work conveying means - Google Patents

Description

C. ALLANDER Filed Jan. 7, 1959 INVENTOR CLAES ALLANDER ATTYS,

Aug. 28, 1962 WEB CUTTER BETWEEN TANDEM-ARRANGED WORK CONVEYING MEANS United States Patent Ofiice 3,051,031 Patented Aug. 28, 1962 3,051,031 WEB CUTTER BETWEEN TANDEM-ARRANGED WORK CONVEYING MEANS Claes Allander, Sodra Angby, Sweden, assignor to Aktiebolaget Svenska Fliiktfabriken, Stockholm, Sweden Filed Jan. 7, 1959, Ser. No. 785,442 Claims priority, application Sweden July 12, 1956 2 Claims. (Cl. 83-424) The present invention relates to web-feeding apparatus and more particularly to a device for lifting and threading a continuous web-like material into a multi-deck drier.

In drying cellulose and similar flexible web-like materials which are continuously fed into a drier, the driers, because of space limitations, usually consist of a plurality of superimposed conveyors upon which the material is transported in zig-zag horizontally extending runs. Since the produced web of paper leaves the screen and dehydrating sections at a relatively low level above the floor of the mill, it has been customary to feed the web onto the lowermost conveyor of the drier. However, to facilitate threading the drier, i.e., feeding the leading edge of the web through the drier when starting the same, it is desirable to feed the web onto the uppermost conveyor of the drier and then successively pass the web to successive subjacent conveyors. Because of the high moisture content and the corresponding low strength of the web, it has previously been impossible to carry out this method practically.

With the foregoing in mind, the present invention provides a simple mechanical device for lifting and threading a continuous flexible web-like material into a multi-deck drier.

More specifically, the present invention provides a pair of cooperating feed rolls for advancing the web toward the drier and lifting means for an elevator disposed behind the rolls to raise the web to the level of the uppermost deck of the drier.

In accordance with the invention, the lifting means or elevator consists of a freely rotatable roll arranged to be moved upwards or downwards in a vertically extending guide or track. The roll, by means of a motordriven hoisting means, is moved with a vertical speed substantially corresponding to one half the feeding speed of the web. The hoisting roll is elevated when a sufficient length of the web has been advanced to drape over and frictionally engage the roll. Thus, as the hoisting roll is raised from a lower position at the level of the feeding rolls to an upper position at the level of the conveyor of the uppermost deck of the drier, the feed rolls advance the web over the hoisting roll so that substantially equal lengths of the web hang from opposite sides of the hoisting roll. At the upper position of the hoisting roll, a drive roll is journalled on a fixed axis in said guide and positively driven at the same rotational feeding speed as that of the feed rolls, the hoisting roll at its upper position being pressed against said stationary roll and forced to rotate. Upon engagement of the hoisting roll with the drive roll, a cutting means is actuated to cut away the leading end of the web and guide the remainder of the web onto the uppermost conveyor of the drier, the cut away portion of the web being discarded.

All of the objects of the invention and the details of the construction and operation thereof will be more fully described hereinafter with reference to the accompanying drawing which shows a preferred embodiment of the invention; wherein:

FIG. 1 is a view in vertical cross section of an apparatus made in accordance with the present invention; and

FIG. .2 is a transverse sectional view taken on the line 2-2 of FIG. 1.

In the drawing, a wet flexible web 1 of material is advanced to the feed device from the screen and dehydrating sections of preceding apparatus (not shown). The web 1 is fed between a pair of cooperating feed rolls, 2, 3 to the lifting means or elevator. The elevator comprises a pair of guides or tracks 4 for a freely rotatable hoisting roll 5 mounted on an endless chain 6. The chain 6 runs between wheels or sprockets 7 and 8 journalled in the guide, and is driven by means of a chain or belt transmission 9 from an electric motor 10.

In the operation of the device, the hoisting roll 5 is in its lower limit position indicated at 5a when the leading edge of the web 1 is introduced between the feed rolls 2 and 3. The feed rolls 2 and 3 are continuously rotating and advance the web 1 over the roll 5. When a sufiicient length of web has been fed over the roll so that sufficient friction between the roll and the web has been attained, the upward advance of the roll 5 is commenced. The motor 10 for hoisting the roll 5 is started either manually or automatically, for example by a switch tripped by the material. During the upward advance, the hoisting roll 5 is given a vertical speed substantially corresponding to one half the feeding speed of the web, so that the parts 1a and 1b of the web on opposite sides of the roll 5 counterbalance each other during the entire upward movement of the roll 5. In its upper limit position indicated at 5b, the hoisting roll 5 is pressed against a drive roll 11 which is journalled on a fixed axis in the rack and is positively driven with a peripheral speed equal to the peripheral speed of the feed rolls 2 and 3. The upward travel of the hoisting roll 5 may be arrested by stopping the motor 10 either manually or by a relay 15 connected to a limit switch 17 operated by the hoisting roll in its upper limit position at 5b. The contacts of the relay 15 .are connected to the motor control box by leads 16. When the hoisting roll 5 is in its upper limit position, it nips the web 1 between the roll 5 and the roll 11. The roll which is not driven during the upward advance thereof is thus caused to rotate at the same peripheral speed as the drive roll 11.

A cutting means 12 is synchronized with the lifting movement of the roll 5 and is arranged to cut the downhanging free part 1a of the web when the hoisting roll 5 is pressed against the drive roll 11. In the present instance, the cutting means 12 comprises a fixed knife 20 mounted on the roll support of hoisting roll 5 and a movable knife 21 slidably mounted in guides 22. A fluid cylinder 23 extends the knife 21 into engagement with the knife 20 and after a slight delay, automatically retracts it to the position shown in FIG. 1. Since the rolls 5 and 11 continuously advance the web 1, the leading cut edge of the web will rest on the knife 21, and as the knife retracts, the leading edge of the web will fall onto the chute 24 and will be guided over to the uppermost conveyor 13 of the drier 14. The cut Off portion 1a of the web is discarded or reprocessed in the preceding apparatus. The cutting means 12, may as an example, be put in motion by means of a solenoid valve 25 controlled by the relay 15.

The drive for the feed rolls 2 and 3 and the drive roll 11 should be synchronized as indicated by the driving connections 26 with the power source 27 for the transporting means of the screen and dehydrating sections, which may be directly connected with the driving means 27 by conventional transmissions not shown in the drawmg.

While a particular embodiment of the present invention has been herein illustrated and described, it is not intended to limit the invention to such disclosure, but

-changes and modifications may be made therein and .thereto within the scope of the following claims.

I claim:

1. A device for lifting and threading a continuous flexible web onto the uppermost conveyor of a multi-deck drier comprising a pair of cooperating feed rolls disposed at a level below the level of said uppermost conveyor for advancing the web toward said drier at a given rate of advance, lifting means intermediate said feed rolls and said drier comprising a vertically extending guide, a freely rotatable hoisting roll mounted in said guide for vertical movement therein, hoisting means operable after advance of the web to drape over and frictionally engage said hoisting roll to displace said hoisting roll in said guide at a speed substantially one half said given rate of advance of the web from a lower limit position at the level of said feed rolls to an upper limit position at the level of said uppermost conveyor, a drive roll journalled in said guide for rotation about a fixed axis adjacent said upper limit position to frictionally engage the web draped over said hoisting roll into the latter position, drive means for said drive roll to rotate the same at a peripheral speed corresponding to said given rate of advance of the web to thereby drive said hoisting roll and advance the web onto said uppermost conveyor, and cutting means .at said upper limit position operable upon engagement of said hoisting roll with said drive roll to cut away the portion of the web suspended beyond said drive roll whereby the remaining portion of the web may be threaded onto the uppermost conveyor of the drier.

2. A device according to claim 1 wherein said drive means for said drive roll includes also drive means for said feed rolls, said drive means operating continuously to uninterruptedly advance the web at said given rate and to continuously rotate the drive roll at a peripheral speed corresponding to said given rate.

References Cited in the file of this patent UNITED STATES PATENTS Swain Sept. 16, 1947 Rankin et al. Aug. 23, 1955

Images