US2733876A

US2733876A - Web tenfskbsr mechanism

Info

Publication number: US2733876A
Authority: US
Publication date: 1956-02-07
Anticipated expiration: 1973-02-07

Description

K. G. LAYCOCK WEB TENSION MECHANISM Feb. 7, 1956 2 Sheets-Sheet 2 Filed Feb. 25, 1953 IN V EN TOR. g6. La ycock W AT TORNEYS no N o a N Kennez United States The present invention relates to web tensioning devices for fitomatically controlling the tension of a paper web as a .is fed'from a web roll to a rotary printing press and has specific relationto new and useful improvements in web 'tensioriing devices of the type shown and described in myfPatent No. 2,637,505 issued May 5, 195 3. @Objects andadvantages of the invention will be set forth in part hereinafter and in part will be obvious here from, or may be learned by practice with the invention, the" same beingrealized and attained by means of the iristrumerrtalities and, combinations pointed out in the appended claims. Y a

' llhe invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and oohs'titu t'ihg'apart hereof, illustrate one embodiment of the invention, and together with the description, serve to eiiplain the principles of the invention.

. the drawings;

, Figure '1' is a side elevation of a typical and preferred "embodiment of the present invention;

Figure 2 is a sectionalview taken along line 22 of Figure I; and

"Figure 3 is a side elevation similar to that of Figure l jb ut lo'okingfrom the other s'icle of the device.

":Tlie present invention has for its object the provision a Web tensioning device that is relatively simple and inexpensive to manufacture .yet highly satisfactory and reliable in its operation; of maintaining a uniform ten- "sio'ntbn 'tlfe'vveh of paper as it is drawn from the web roll andfed 'into the rotary printing press. A further object isto provide a web tensioning device with novel means eif tivie to maintain the web at a substantially u'inform tension even .though the Web roll is out of round or otherwise irregular.

l n 'ordancawitha preferred embodiment of the pre invention atoll ofpaper is rotatably mounted in h suitableltrame and a web is fed from the roll into a "rotary printing press passing over a .pilot'roller on its way to" the press: The pilot roller is rotatably mounted betw en "apa'ir of arms that are secured to a shaft which is 'io'urnaleddn upright frame members, and through this mounting means the pilot ro'ller'i's moved about the axis 'ofsa'rdshaftby changesin web tension. The tension of the wee isgoverned by "brake means operable to fric- --"tio"ria'lly resist rotation of'the web roll and the operation of isflirake*meansisregulated by the pilot roller through suitable linkage mechanism arranged so that when the pilot roller is moved by anincrease in web tension the brake applied tiietion is decreased and vice versa.

- Theforc'e'which theweb tension exerts against the pilot roller is opposedby the Weight of a mass of considerable magni tude'whiohzaots vthrough the shaftto which the pilot roller supporting. arms are connected to urge the pilot roller'iin a'direotion opposite to zthat in which the web urges rtlre ipilot rnller. Thismass is connected to the I :haft through aupivdted lever, the pivotal support for atent ice which is a spring biased lever provided with a curved supporting arm and pivoted to a bracket member that is journaled to the shaft. Means are provided for secur ing the bracket member to the shaft at any desired angular position about the shaft. Angular movement of the bracket with respect to the shaft has the effect of varying the leverage ratio of the spring biased lever whereby the lever is able to support masses of varying r'nag nitude without changing the magnitude of the spring bias applied to the lever.

It will be understood that the foregoing general description and the following detailed description as well are exemplary and explanatory of the invention but are not restrictive thereof. g

Referring now to the drawings, wherein like numerals are used throughout to designate like elements, the illiis trative and preferred embodiment shown therein corn prises a web roll 10 wound about shaft 12 which is rotat ably supported at each end in spaced members 14 which extend laterally from upright frame members 16. A web of paper 19 is drawn front the roll serially passing under guide roller 18, over" pilot "roller 20 and under guide roller 22, after which it enters the rotary printing press not here shown. Tension iscreated in web 19 by means of a brake whi'chcomprises brake drum '24 g and brake shoes 26. The brake shoes are pressed toward each other and into contact "with drum 24;;by means of lever arms 28 which are pivota'lly supported by a lii ik 36 mounted on spaced frame member 14'by means of the side lay adjusting wheel 32. The other'endsxof levers 28 are interconnected by means of turnbuckle link 34,

the upper end of which is connected "to a bell crank '36 having a long upwardly extending arm 38 and a short lever arm at, the short lever arm detachably connecting the upper end of link 34 with the adjacent end of upper lever arm '28. The length of link '34 may be varied to compensate for wear of brake shoes 26 by turning hand wheel 42 which will thread the rod that forms a part of the link into or out of the link end members. 7

The frictional force exerted by the brake to tensionvveb I9 is accurately regulated by pilot roller 20 which is rotatably supported intermediate spaced arms #4 which in turn are pivoted in uprightframe members lti by means of shaft 46 and are preferably counterbala'hced by means of variably positionable weight 48'; Shaft {45 is fastened to each of the arms 44 by means of pins 51 (Figure 2) and is mounted in bearings "50 secured within suitable openings provided in the spaced upiight "frame members 16. One end of the shaft that projects beyond one of the frame members is provided with depending arm 52 keyed to the shaft at a fixed angular position rela tive to arms 44 and connected to arm 38 of bell crank 36 through link 54.

The brake mechanism and its "interconnection with pilo't roller 20 is such that when an increase in web tension causes the pilot roller to move downward bell crank 36 is moved counterclockwise as viewed in Figure 3 to lessen the pressure that brake shoes 26 exert against brake drum 24 causing a reduction in the frictional resistance opposing the rotation of web roll 1'9 'and'resulting in lessening large mass 56 actingthrough shaft 46 by means or a linkage arrangement having a spring biased pivotalisupport. 2 The linkage arrangement comprises arm'58 keyed by changing the weight of mass 56 and fine adjustments being made by moving member 66.

While spring mechanism 62 is here disclosed as embodied in an installation wherein it is desirable to adjust the mechanism so as to maintain a substantially constant spring compression for varying load conditions it is to be understood that this mechanism is also applicable to installations where it is desirable that the applied force of the spring be varied.

The invention in its broader aspects is not limited to the specific mechanism shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. In a shock absorbing spring mechanism adapted to provide a readily adjustable leverage ratio acting upon the spring of the mechanism the combination of a rotatable shaft, an arm mounted on the shaft, a lever pivotally secured at one end of the arm, said lever adapted to have a load applied thereto, a generally cylindrical bracket member mounted on said shaft, means securing said bracket to said shaft at desired angular positions, said bracket having a pair of angularly spaced outwardly projecting ears, a second lever pivotally connected intermediate its ends to one of said ears for pivotal movement about an axis generally parallel to said shaft, at least a portion of the lever on one side of said pivotal connection being curved and generally concentric with said shaft, the other of said ears having an opening therein with a spring rod projecting therethrough and pivotally connected to the extremity of the portion of the lever on the other side of said pivotal connection, a cam follower on the firstmentioned lever bearing on the curved portion of the second lever and a coil spring disposed over said rod and compressed between the free end of the rod and the ear through which the rod projects.

2. In a web tensioning device for controlling the tension of a web drawn from a web roll, means for applying friction to the web roll to tension the web, and a pilot roller moved by changes in web tension and connected to increase or decrease the friction applied to the web roll, an increase in web tension causing a decrease in the friction, the combination of a mass connected to the pilot roll through a pivotally supported lever and operable to urge the pilot roll against the tension of the web, the pivotal support for said lever comprising a pivoted lever spring biased to oppose the weight of said mass acting at the point of pivotal support of the first mentioned lever, said spring biased lever being movable with respect to said point of pivotal support to change the leverage ratio of the spring biased lever thereby changing the effectiveness of the spring bias.

3. A web tensioning device as claimed in claim 2 including means to adjust the position of the mass relative to the point of pivotal support of the first mentioned lever.

4. In a web tensioning device for controlling the tension of a web drawn from a web roll, means for applying friction to the web roll to tension the web, and a pilot roller moved by changes in the web tension and connected to increase or decrease the friction applied to the web roll, an increase in web tension causing a decrease in the friction, the combination of a mass connected to the pilot roll through a pivotally supported lever and operable to urge the pilot roll against the tension of the web, the pivotal support for said lever including a pivotally mounted member having a curved support arm, means operable to secure the pivotal mounting for said member at desired angular positions about a given axis generally parallel with the pivotal axis of the member, the arm of said member being curved about said given axis, and resilient means effectively disposed between the member and its mounting urging the arm against the bias of the weight of the mass.

5. A web tensioning device as claimed in claim 4 in which the curved supporting arm is concentric with the given axis.

6. A web tensioning device as claimed in claim 4 in which the resilient means is a spring having means to adjust the force that it exerts upon said member.

7. In a web tensioning device for controlling the tension of a web drawn from a web roll, the combination of friction means restraining the rotation of the web roll, a shaft mounted for rotation about a given axis, a pair of coplanar spaced arms secured to said shaft, a pilot roller rotatably mounted intermediate said arms and moved about said given axis by changes in tension of the web, means effective to impart movements of said roller to the friction means to increase the applied friction upon a decrease in web tension and decrease said friction upon an increase in web tension, an arm secured to said shaft, a lever pivotally connected to said arm, said lever supporting a mass, means pivotally supporting said lever so the weight of said mass is effective to urge the pilot roll against the tension of the web, the pivotal support including a bracket rotatably mounted on said shaft, means for securing said bracket at desired angular positions about said shaft, lever means pivoted to said bracket about an axis generally parallel with said given axis, said lever having an arm curved about said given axis and upon which the first mentioned lever is supported, spring means effectively disposed between the bracket and the second mentioned lever operable to urge the same in oppo' sition to the action of the weight of the mass at the point of pivotal support of the first mentioned lever.

8. A web tensioning device as claimed in claim 7 in which said curved arm is concentric with said given axis.

9. A web tensioning device as claimed in claim 7 in which means are provided for adjusting the force which the spring exerts upon the second mentioned lever.

10. A spring mechanism for a web tensioning device comprising a rotatable shaft, an arm mounted on the shaft and rotatable in one direction to increase the tension on the web and in the opposite direction to decrease the tension on the web, a lever pivotally secured at one end to the arm, said lever having a load applied thereto in a direction tending to rotate the arm in a web tensionincreasing direction, a cam follower on the lever, a second pivoted lever mounted to engage the cam follower on the first-mentioned lever, said second lever having an adjustable pivot whereby the distance between the cam follower of the first-mentioned lever and said pivot may be varied to change the leverage ratio of the load bearing on the second-mentioned lever through the cam follower, and a spring secured to one end of the second lever to oppose movement of said second lever in a web tensiondecreasing direction.

11. A spring mechanism for a Web tensioning device as set forth in claim 10 in which the pivot for the second lever is mounted on a bracket rotatable with the shaft, the pivot being adjustable by said bracket being adjustable with respect to the shaft so as to vary the distance between the cam follower and said pivot.

References Cited in the file of this patent UNITED STATES PATENTS 553,987 Heath et al. Feb. 4, 1896 1,180,154 Johnson Apr. 18, 1916 2,243,678 McKean May 27, 1941 2,623,703 Laycock Dec. 30, 1952 2,637,505 Laycock May 5, 1953 2,637,506 Laycock May 5, 1953 Feb, 7, A. B. CUNNINGHAM 2,733,?7

THREAD AND YARN DISPENSER Filed May 29, 1952 Albert E. Gummy/2am zzvmvroze.