US2099313A - Unwinding apparatus for paper webs and the like - Google Patents

Description

*Nov.16,1937.' A. POTDEVIN 2,099,313

unwmnme APPARATUS FOR PAPER .WEBS AND THE LIKE Filed Oct. 8, 1955 ATTORN EY5 Patented Nov. l6, 1937 UNITED STATES UNWINDING APPARATUS FOR PAPER WEBS AND THE LIKE Adolph Potdevin, Garden City, N. Y., assignor to Potdevin Machine Company, Brooklyn, N. Y.,

a corporation of New York Application October 8, 1935, Serial No. 44,000

1 Claim.

In all types of machines utilizing continuous webs wound in tells, it is necessary or desirable in drawing the web from the roll by constant speed mechanism, such as positively driven friction forwarding rolls, that the tension on the a friction device is employed contacting with the periphery of the roll being unwound, that the friction applied to the roll must be greater at thebeginning of the unwinding operation than at the end of the operation, this friction decreasing in direct proportion to decrease in the diameter of the roll. This is taken care of automatically in the present invention.

I also provide in the machine of this application for varying the applied friction initially so as to accommodate the machine to various widths of web and different materials.

.In the accompanying drawing:

Fig. 1 is a side view of a machine embodying my invention with the parts in position with a full roll of paper;

Fig. 2-is a similar view but with the roll of paper nearly depleted: and

Fig. 3 is a plan view of the showing of Fig. 1.

Referring more particularly to the drawing, I designates the roll of paper which is to be unwound, this roll being supported on shaft 2 which in turn is supported in bearings in the two side frames 3 and l of the machine.

1 Contacting the periphery of the roll of paper I is a belt 5 removably secured at one end to a bar 6 supported in uprights 6', the bar being located above the roll I and extending lengthwise thereof. The other end of the belt is made fast to'a drum I which is mounted on a shaft 8, supported in suitable bearings on the side frames 3 and 4, this drum being positioned below and slightly to one side of the roll. The shaft 8 carries a gear 9 which meshes with a gear I fixed to shaft II.

Afllxed to the shaft IIv is an arm I2 which carries a weight I3. The weight I3 is adjustable along the arm toward and away from the shaft I I. Aflixed to the shaft II and projecting from the shaft at the side opposite the arm I2 is anshaft '6. The full roll I may now be placed in.

position, the belt passed about the periphery of the roll and its upper end again secured to the shaft 6.

(Cl. v 242-45) Inasmuch as with a full roll the distance from the center of the roll tothe point where the web is leaving the roll is greatest, it will be apparent that at this time the pressure of the belt 5 on the face or periphery of the roll should be greatest. Accordingly the arm I2 and weight I3 are rotated clockwise to position where the arm is horizontal, thus attaining the greatest leverage from the pull of gravity. The weight I3 is then adjusted along the arm I2 until the desired pressure is produced on the periphery of the roll to give the desired tension in the web as it is unwound. It

will be evident that as the web is drawn off the roll and the virtual diameter of the roll decreases, the weight l3 will gradually lower and at the same time the belt 5 will be wound upon the drum ,1, the latter rotating in an anti-clockwise the periphery-of the roll I, and this action in conjunction with the ratiobetween the gears 9 and I0 is such that the pressure of the belt on the roll periphery will decrease in direct proportion to the reduction in the virtual diameter of the roll I due to the unwinding of the web, that is,'in direct proportion to the reduction in the length of the lever arm represented by .the distance from the center of the roll I to the point where the web leaves the roll. It will be apparent, therefore, that when this lever arm is shortest i. e., when practically all of the paper has been unwound the pressure of the belt 5 on the periphery. of the roll is at a minimum.

What I claim is:-

.Unwinding apparatus for rolls of strip material, comprising in combination a frame, means for rotatably supporting a roll to be unwound on said frame, a belt having one end anchored to said frame above said roll and passing about the roll and contacting the periphery thereof, a drum.

having the other end of said belt secured thereto, a weight, a lever on which said weight is adjustably mounted, a gear for gearing said lever to said drum, said weight swinging in an are by gravity concentric with said gear as the roll is unwound to wind the belt on said drum thereby uniformly to decrease the contact pressure of the belt on the roll periphery in direct proportion to the uniform reduction in the virtual diameter of the roll as unwinding proceeds,

whereby maximum belt pressure is applied to the roll periphery when the roll diameter is maximum and minimum belt pressure when the roll diameter is minimum. k

. ADOLPH PO'IDEVIN.

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