US2261891A

US2261891A - Web-tensioning device

Info

Publication number: US2261891A
Application number: US255261A
Authority: US
Inventors: Roy A Stewart
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-02-08
Filing date: 1939-02-08
Publication date: 1941-11-04
Anticipated expiration: 1958-11-04

Description

Nov. 4, 1941. R. A. STEWART WEB-TENSIONING DEVICE Filed Feb. 8, 1939 3 Sheets-Sheet l INVENTOR ROY A. STEWART ATTOf N Nov. 4, 1941. R. A. STEWART WEB-TENSIONING DEVICE Filed Feb. 8, 1959 3 ShaetS-Sheet 2 o INVENTOR ROY A. STEWART Nov. 4, 1941. R. A. STEWART 2,251,391

WEB-TENSIONING DEVICE Filed Feb. 8, 1939 3 Sheets-Sheet S INVENTOR ROY A. STEWART ATTOR Patented Nov. 4, 1941 UNITED STATES PATENT OFFICE WEB-TENSIONING DEVICE Roy A. Stewart, Decatur, 111-.

Application February 8, 1939, Serial No. 255,261

Claims.

This invention relates to web supply apparatus and in particular to apparatus to control the unwinding of a plurality of web rolls such as may b used to feed one or more webs to a multideck or unit rotary printing press.

It is desirable in feeding web to a printing machine that there be a tension produced in the web to facilitate good printing and this tension may be providedby braking the web roll. By controlling this braking of the web roll according to the tension in the web many advantages are obtained which include uniform web tension during unwinding of the web roll and the prevention of overrunning of the web roll should the web break or the feeding of the web roll stop suddenly. With the use of high speed printing machines it becomes increasingly desirable to be able to feed a web under substantially uniform tension during the life of the supplying web roll, without manual adjustment, or during an entire printing run, so that once the printing machine is started it need not be stopped, barring breakdown, until the printing to be done is completed.

It is an object of the present invention to provide web tension apparatus such that one or more webs may be continuously and successively fed from a plurality of web rolls as they expire, each of the continuous webs being controlled by the same web tension control mechanism throughout.

A further object is to provide web control apparatus whereby a plurality of web rolls may be controlled by the tension in one web.

Another object is to provide apparatus of the type mentioned which is simple in design and construction and inexpensive to manufacture, and which may be operated with a minimum of supervision.

Other objects and advantages will become apparent from the following detailed description at:- companied by the drawings, in which:

Figure 1 is a diagrammatic view of a system of web rolls from which may be fed a plurality of webs, illustrating a supply system embodying the present invention;

Fig. 2 is a side elevation showing the control system for controlling the tension in a web and the unwinding of the web roll;

Fig. 3 is an enlarged sectional view taken substantially on line 3-3 of Fig. 2;

Fig. 4 is an enlarged sectional view taken substantially on line 4-4 of Fig. 2;

Fig. 5 is an end elevational view taken substantially on the line 5-5 of Fig. 2, showing construction details of the control mechanism; and

Fig. 6 is a side elevational view'showing further construction details of control mechanism.

In brief, one practical application of web supply apparatus embodying the present invention comprises a tension responsive device associated with the web to maintain substantially uniform tension by transmitting changes in web tension to suitable braking means on the web roll and by applying or releasing the braking means to correct the change in web tension. It has been found that one very desirable way of doing this is to have the tension responsive device connected with a primary hydraulic fluid brake cylinder which may b selectively connected to a plurality of secondary hydraulic fluid brake cylinders adapted to operate the braking means. In the embodiment of the invention shown herein the tension responsive device creates amechanical force suitable to correct the braking means and this'mechanical force is converted by the primary brake cylinder to hydraulic fluid pressure which may be transmitted to the secondary brake cylinder, reconverted into a mechanical force and used to apply or release the braking means. The use of a hydraulic fluid system is very advantageous because the transmittal of force to any of a plurality of varied locations is greatly facilitated.

With reference to the accompanying drawings, in which like parts throughout the several views are indicated by the same reference numerals, a system of web supply apparatus is shown diagrammatically in Fig. 1. A plurality of web rolls are shown arranged in four decks so that, if desired, from one to four webs may be fed simultaneously to a printing machine, such as, for example, a multi-deck or unit rotary printing press. Deck I contains web rolls R1 and R2 and a web W1 is fed from this deck. The parts of mechanisms located in this deck will be denoted by numerals below 100. Deck II contains web rolls R3 and R4, feeds a web W200 and the parts situated in this deck will be denoted by numerals in the two hundreds. In a similar manner, decks III and IV contain web rolls R5, R6 and R7, R8 respectively, and feed webs W300 and W400 respectively. Parts situated in decks III and IV will be denoted by numerals in the three hundreds and four hundreds, respectively. This grouping into decks and numbering the parts according to decks has been arbitrarily chosen for the sake of brevity and clarity of description. Since the mechanism in each deck is substantially similar, only that in deck I will be fully described.

Web rolls R1 and R2 may be carried by'suitable web roll shafts I mounted for rotation in a suitable frame or roll stand 2. The brake mechanism for the web rolls is shown in Figs. 2, 3 and 4 and comprises the brake bands 3 carried by

arcuate brake shoes

4 and 5 which are pivotally connected at one end about a pivot 6. The opposite or free end of the shoe 5 terminates in an upstanding lug l which is apertured to receive an eye bolt 8 which is inserted so that the enlarged portion I0 of the eye bolt remains on the outside of the shoe. The shaft portion H of the eye bolt passes through an aperture in the upstanding lug |2 on the free end of the brake shoe 4 where its threaded portion may carry a hand wheel |3. Pivoted at the eye portion III of the eye bolt 8 is a bell crank lever I4.

This lever has a free long arm |5 which'is bifurcated to provide a pair of short arms I6 pivoted to the brake shoe 5 by a pivot which passes through the arms l6 and also through boss integral with the brake shoe. The brake mechanism may be operated to effect braking of the web roll by exerting force on the arm |5 of the lever |4 so that the arms l6 of the lever l4 force the shoe 5 toward the shoe 4 to create an increased pressure of the band 3 against a drum |8 carried by the web roll shaft Further, the brake may also be operated by turning the hand wheel |3 when the lever arm 45 is held so that the shoes are drawn one toward the other by the action of the bolt 8, the enlarged portion of which serves to support the lug 1 of the shoe 5, while the hand wheel .advances the lug l2 of the shoe 4.

A web W1, fed from deck I, is led upwardly over a guide roller around a guide roller 2| back around a guide roller 22, then forward again over a guide roller 23, from which it passes to the rolls or printing cylinders of the printing machine (not shown). The guide roller 23 is journaled in the side frame 2 while the

guide rollers

20, 2| and 22 are carried'by .a pair of spaced brackets 24 secured to the frame 2. Of course, one or more of the guide rollers may be mounted, as, is well known in the art, so as to l be spring pressed against the web to cushion the web from shocks which would tend to break ,or tear the web. Between

guide rollers

22 and 23 the web is passed under a movable or floating control roller 25 carried by the ends of arms 26 which are pivotally mounted on a shaft 29 which is supported in the brackets 24 and around which the guide roller 20 freely rotates. At one side of the frame 2 a lever arm 21 is provided and it is pivotally mounted on the end of the shaft 29 and secured so as to move with the arms 26 (see Figs. 5 and 6). One end of the lever 21 carries a weight 28 which may be adjustably positioned at various distances from the pivot point. The other end of the lever arm 21, located on the opposite side of the pivot point, is pivotally connected to a piston rod 30 of a dash pot 3| which is pivotally anchored to the frame 2 at 32.

The weight 28 tends to rotate the arms 26 in a counterclockwise direction (looking at Fig. 6) so as to draw the web into a loop between the

rollers

22 and 23 to substantially the positions shown in dotted line. The weight 28 is made adjustable along the lever 21 so that it may be positioned to induce the various desired tensions to be maintained in the web. The dash pot 3| is provided so that upon an emergency stopping of the web feed or a sudden braking of the web the,

movement of the arms 26 from the solid line position to the dotted line position shown in Fig.

6 may be effected in a gradual manner. Movement of the arms 26 produces either an increase or a decrease in the braking pressure of the brake shoes against the drum and the web roll,

Means for transmitting the mechanical movement of the arms 26 to the primary brake cylinder for conversion into fluid pressure are shown in Fig. 2, where it may be seen that on the side of the frame 2 opposite the adjustable weight and dash pot mechanism, an arm 26a is mounted on and keyed to the shaft 29 so as to move with the arms 26. The arm 26a is provided with an outwardly extending roller 33 which bears against the free end of the lever 34 pivoted at 35. The

pivoting of the lever 34 is obtained by afiixing one end of the lever to an end of a small shaft '36 which extends through and is journaled in the side walls of a box or container 31 rigidly secured to the frame 2 in a suitable manner. On the interior of the container 31 the shaft 36 carries a small arm 38 which, being fixed to the shaft, 'moves with the lever 34. The arm 38 bears against a plunger 40 which is reciprocably mounted in a primary hydraulic fluid brake cylinder 4| contained within the box 31. The end of the cylinder 4|, inwardly of the plunger, opens into a pipe or conduit 42 which communicates with a header 43 from which fluid pressure created by the plunger may be transmitted to one or more of the tubes or

lines

44, 45 and 46 connected through

valves

41, 48 and 49 respectively, to the header 43 (see Fig. 2).

As shown in Fig. 2, the flexible tube 45 may, by opening the valve 48, communicate with a secondary hydraulic fluid brake cylinder 50 which may be bolted a spaced distance from the brake shoe 5. A plunger 5| is reciprocablymo'unted in the cylinder 5|! and its plunger rod bears against the free'end of the long arm l5 of the bell crank lever l4. Thus, should the web become loose and allow the roller 25 to drop, causing the arms 26 to rotate from the full line position (Fig. 2) in a clockwise direction to their dotted line position, due to an insuflicient tension in the web W1 which is being withdrawn at present from the roll R1, the mechanical movement of the arms 26 will be transmitted through the

levers

34 and 38 to the plunger 40, converted to an increased fluid pressure which is transmitted through conduit 42, header 43, and the tube 45 which communicates with the secondary cylinder 50, the side walls of which are afiixed to the brake shoe 5 of the brake located on the web roll R1. In thecylinder 50 the increased fluid pressure will be converted by the plunger 5| to mechanical force which will actuate the bell crank lever and tighten the

brake shoes

4 and 5 so that the web roll R1 will not unwind as swiftly and the amount of the Web W between the guide rolls 22 and 23 will decrease, thereby drawing the floating control roller 25 back up toward the full line position shown in Fig. 2 and increasing the tension in the web. It may be readily seen that drawing the roller 25 upwardly will operate to decrease the braking effect on the web roll R1, and thereby compensate the tension.

When the proper tension, determined largely by the adjustable weight, has been established, it will be automatically maintained by the control means described above.

Should the withdrawal of the web W1from web roll R1 be stopped suddenly, or should slack occur in the web W1, the arms 26 will rotate relatively quickly in a'clockwise direction (looking at Fig. 2) to the dotted line position shown therein and braking of the web roll R1 will be effected, thereby preventing overrunning of the web. 3

Apparatus embodying the present invention is very advantageous in that it also provides a very flexible system of control of a plurality of web rolls. For example, it may be seen from Fig. 1 that the tension control roller 25 associated with the web W1 may control not only the web roll R1 from which the web W1 is being withdrawn, but may also control the web rolls R2 and R4. by transmittal of fluid pressure through the

tubes

44 and 46 respectively.

By having one tension control roller control the brake mechanism of several web rolls, a single web may be fed in the same path successively from the several web rolls as they expire without changing the setup of the machine. If it is desired to feed one web to the printing machine and the amount of printingbeing done requires a length of web equivalent to between two and three web rolls, the web may be continuously supplied from the apparatus shown in Fig. 1 by operation in the following manner. The web is withdrawn from the web roll R1 with the valve 48 open to permit the tension mechanism to control the web roll R1. As the web from web roll R1 is about to expire, the leading edge of web from web roll R2 is afiixed thereto by what is commonly known in the art as a paster or splice. As web begins to be withdrawn from web roll R2 the tension control thereof may be obtained by opening the valve 47 on line 44 leading to the web roll R2 and closing valve 48 on line 45 leading to the now expired r011 R1. By a similar pastel, web from the web roll R4 may be connected to the web from web roll R2 as it expires and the continuous feeding of web from deck I may continue, such web, however, being withdrawn from web roll R4 situated in deck II. The tension control of the web withdrawn from web roll R4 is controlled by the control roller 25 operating to control web roll R4 by communication of fluid pressure through line 46 when the valve 49 is opened.

In deck II the tension control roller 225 associated with web W200 may control not only Web withdrawn from web rolls R3 and R4 situated in deck II through

lines

262 and 26! respectively, but also web withdrawn from web rolls R2 and

Rethrough lines

260 and 263 respectively.

The web W300 in deck III may be withdrawn from web rolls R4, R5, R6 and R8 and the tension control roller 325 may control the web rolls mentioned through the

lines

364, 366, 365 and 361 respectively.

Similarly, the web W400 in deck IV may be withdrawn from web rolls R0, R2 and R2 and the tension control roller 425 may control the web rolls mentioned through lines 468, 410 and 459 respectively.

Of course, it may be seen that the system shown in Fig. 1 is merely illustrative and the tension control mechanism of any deck could be arranged so as to control as many web rolls as may be practically desirable. This invention may be applied to many types of printing machines having one or more printing units into which a continuous web may be fed and printed. Such printing machines may include rotary presses of the unit as well as the multi-deck type, such as are used in the printing of newspapers and the like.

As another example of the operation of the system shown .in Fig. I, assume that it be desired to feed two webs simultaneously from decks II and III and a continuous web of between two and three web rolls in length is required for the printing job. Fresh web rolls may be placed on all the web roll mounts during a period when the printing machine is shut down. Then the feeding of webs W200 and W300 simultaneously may be started. Web W200 may be successively drawn from web rolls R3, R4, and R2, all of which may be controlled by the control roller 225 associated with the web W200. Web W300 may bewithdrawn from web rolls R5, R6, and Rs in succession, all of said rolls being controlled by the control roller 325 associated with the web W300.

'It may be noted that when a plurality of webs are being withdrawn simultaneously, and one of such webs breaks, the ,Web roll from which it is being withdrawn will be automatically stopped in a relatively short time. Such breakage will necessitate a stoppage of the printing machine which will automatically stop any of the remaining webs left running, because stopping the printing ,will allow the-occurrence of slack in such webs, thereby permitting a movement of the control rollers which, as previously described, is transmitted to the braking means on the web rolls, preventing overrun of the web rolls. Further, if trouble should begin at the printing machine, it is only necessary to stop the machine to prohibit feeding of the webs in a relatively quick time.

It is to be understood that variations and modifications of the specific devices herein shown and described for purposes of illustration and explanation, may be made without departing from the spirit of the invention.

What I claim is:

1. Web supply apparatus for feeding one or more webs to a multiple-deck printing machine which comprises a stationary frame for holding web rolls in decks corresponding to the decks of the printing machine, said frame adapted to hold one or more web rolls in each deck, braking means associated with each of said web rolls, means for withdrawing a web from each of said decks simultaneously, tension-responsive control de-..

vices associated with the web of each deck between the web rolls thereof and the withdrawing means thereof, a primary hydraulic brake cylinder for each deck, operable by the tension-responsive device thereof, a secondary hydraulic brake cylinder situated adjacent each web roll to operate the braking means thereof, and means for selectively connecting the primary brake cylinders of each deck to one or more of the secondary brake cylinders, which need not be disposed in the same deck.

2. Web supply apparatus which comprises a plurality of web rolls, braking means for each of said web rolls, means for withdrawing webs from said web rolls, a tension control mechanism associated with each web between the web rolls and the withdrawing means for maintaining substantially uniform web tension, a primary hydraulic fluid brake cylinder for each control mechanism operable by said control mechanism, a plurality of secondary fluid hydraulic brake cylinders each of which is adapted to operate the braking means of one of said Web rolls, and means to selectively connect any of the primary cylinders to a plurality of said secondary cylinders at the same time.

3. Web supply apparatus which comprises a plurality of web rolls arranged in decks for feeding web to a printing machine having a plurality of printing units, means for' withdrawing a web at each ofsaid decks; braking means for each of said web rolls, a tension control mechanism associated with each of the webs between the web rolls and the withdrawing means formaintaining substantially uniform web tension, a primary hydraulic fluid brake cylinder for each deck operable by the control mechanism of said deck, a plurality of secondary hydraulic fluid brake cylinders each of which is adapted to operate the braking means of one of said web rolls, and means to selectively connect any of the primary cylinders to one of a plurality of secondary cylinders, which need not be in the same deck.

4. Web supply apparatus which comprises a series of web rolls, a brake for each of said rolls, a plurality of independent web withdrawing means, each adapted to withdraw the web from any one of said rolls, a controlling member associated with each web withdrawing means, each controlling member being movable in response to variations in web tension, and means for selectively connecting any one of said controlling members to any one of said brakes to operate the brake so connected in response to variations in web tension whereby the tension of a web withdrawn from any roll by any of the web withdrawing means may be automatically regulated by the control of the brake of the web roll from which the web is being withdrawn.

5. Web supply apparatus which comprises a series of web rolls arranged in decks for feeding web to a printing machine having a plurality of printing units, means at each of said decks for withdrawing a web from any roll of a plurality of decks, a brake for each of said web rolls, a controlling member associated with each web withdrawing means, each controlling member being movable in response to variations in web tension, and means for selectively connecting each of said controlling members to the brakes of any one of the rolls on a plurality of decks to operate the brake so connected in response to variations in web tension, whereby the tension of the web withdrawn from any of a plurality of rolls by any one of a plurality of web withdrawing means may be automatically regulated by the control of the brake of the web roll from which the web is being withdrawn.

' ROY A. STEWART.