US3419228A

US3419228A - Web tensioning apparatus

Info

Publication number: US3419228A
Application number: US606810A
Authority: US
Inventors: Charles A Harless
Original assignee: Harris Intertype Corp
Current assignee: Harris Graphics Corp
Priority date: 1967-01-03
Filing date: 1967-01-03
Publication date: 1968-12-31
Anticipated expiration: 1985-12-31

Description

31, 1968 c. A. HARLESS WEB TENSIONING APPARATUS Sheet Filed Jan. 5, 1967 INVENTOR CHARLES A. HARLESS FIG 2 ATTORNEYS Sheet G. v R m. M. 3 5 7O l 4 4 J l i L F m M 5. m I m I "M Q U 3 II V V 10 H T a M I 5 O I l d 1 a u W H. '01 1. Z I W I I, 1 ilH .w 1 5 I J I Q 6y m T u Tmm 2 7O H q 3 l I! w n llll 7 6 m m 0% 4 Dec. 31, 1968 Filed Jan. 3, 1967 United States Patent Office 3,419,228 Patented Dec. 31, 1968 3,419,228 WEB TENSIONING APPARATUS Charles A. Harless, Fort Worth, Tex., assignor to Harris- Intertype Corporation, Cleveland, Ohio, a corporation of Delaware Filed Jan. 3, 1967, Ser. No. 606,810 13 Claims. (Cl. 24275.43)

ABSTRACT OF THE DISCLOSURE A web tensioning apparatus for tensioning a web being fed from a rotatable roll stand comprises a brake drum which is operatively connected with the web roll. Brake shoes frictionally engage the brake drum to effect a braking thereof and an actuating mechanism is operatively connected with the brake shoes for effecting movement of the brake shoes into frictional engagement with the brake drum. The brake shoes are adjustable axially of the web roll to effect alignment of the brake shoes with the brake drum by a plurality of members which are movable axially to effect axial movement of the brake shoes. An actuating mechanism which effects movement of the brake shoes into frictional engagement with the brake drum includes a flexible link. The brake shoes are pivotally connected to side walls of a U-shaped brake shoe carrier for pivotal movement relative thereto.

The present invention relates to a web tensioning apparatus, and in particular to a web tensioning control apparatus for controlling the tension of a web being fed through a pair of cooperating rolls in a rotary machine, such as a printing press.

A known web tensioning apparatus heretofore employed for tensioning a web being drawn from a rotatable web roll has included a brake means for applying a braking force to a brake drum carried by the web roll to place the web under tension and a brake actuating mechanism for actuating the brake means to apply a braking force to the drum. This known apparatus additionally included supports for slidably supporting the brake means for movement in directions axially of the web roll to enable the side lay of the web roll to be adjusted relative to its support stands and an adjustment screw laterally spaced from the supports for slidably moving the brake means along its supports. This known web tensioning apparatus, however, has not been entirely satisfactory, since a binding action between the brake means and its supports often occurred when the adjustment screw was rotated to move the brake means relative to its support to adjust the side lay of the web roll. This binding action made adjustment of the side lay of the web roll difficult at times. Also, this known web tensioning apparatus was of a relatively complex and expensive construction, especially the construction of the brake means.

Accordingly, it is an important object of the present invention to provide a new and improved web tensioning apparatus having brake means for applying a braking force to a cooperable brake drum carried by a rotatable web roll to cause the web being fed therefrom to be placed under tension and a brake actuating mechanism for actuating the brake means to apply a braking force to the brake drum, and which is of a highly practical and economical construction and reliable in operation, and wherein the brake means is adjustably supported for movement in opposite directions axially of the web roll to adjust the side lay of the web roll and in a manner such that binding between the brake means and its support is eliminated or minimized.

Another object of the present invention is to provide a new and improved web tensioning apparatus of the character referred to and in which the brake means comprise a pair of brakes which are pivotally supported on sleeves threadably engaged with threaded support shafts extending axially of the web roll whereby the brakes can be readily easily moved axially of the web roll to adjust the side lay of the latter by relatively rotating the sleeves on support shafts.

Yet another object of the present invention is to provide a new and improved web tensioning apparatus of the character referred to and wherein the actuating mechanism includes a flexible linkage means operatively connected with the brake means so that the brake means can be adjusted in directions axially of the web roll without necessitating adjusting the relative positions of other parts of the actuating mechanism.

A further object of the present invention is to provide a new and improved web tensioning apparatus for tensioning a web being fed from a web roll and having a brake means for engaging a brake drum on the web roll to apply a braking force thereto to tension the web, and in which the brake means includes a brake shoe for frictionally engaging the brake drum and which is directly pivotally connected to a movable brake shoe carrier or arm, and wherein the brake shoe and brake arm are of a more simple and economical construction than known brake constructions.

The present invention further resides in various novel constructions and arrangement of parts, and further objects and advantages of the present invention Will be apparent to those skilled in the art to which it relates and from the following detailed description of the illustrated embodiment thereof made with reference to the accompanying drawings forming a part of this specification, and in which similar reference numerals are employed to designate corresponding parts throughout the several views, and in which:

FIG. 1 is a fragmentary side elevational view of a web tension control apparatus embodying the present invention;

FIG. 2 is a fragmentary elevational view of the web tension control apparatus shown in FIG. 1 and looking in the direction of the arrows 22;

FIG. 3 is an isometric view of part of the tension control apparatus shown in FIG. 1;

FIG. 4 is a fragmentary top plan view of the tension control apparatus shown in FIG. 1; and

FIG. 5 is an enlarged fragmentary sectional view taken approximately along line 55 of FIG. 1.

The present invention provides a novel web tension control apparatus for controlling the tension of a web fed from a Web roll to an apparatus or machine for operating on the web. Although the web tension control apparatus of the present invention is susceptible for use in or in conjunction with various kinds of apparatuses or machines for operating on web material, it is particularly useful for controlling the tension of a web being fed to a rotary printing press, and for the purposes of illustration is herein shown and described as being used for controlling the tension of a paper web W being drawn from a paper web roll 12 by a pair of cooperable rolls of a rotary printing press (not shown).

Referring to FIG. 1 of the drawings, the paper web roll 12 is there shown as having a shaft 13 whose opposite ends are rotatably supported on suitable bearings carried by a pair of laterally spaced upstanding support stands 14. The web roll 12 is rotated in the direction of the arrow 15 as the web W is drawn therefrom and the web W is trained around an idler roller 16 and around a dancer roller 18 as it is advanced toward the printing press.

The web tension control apparatus for controlling the tension of the moving web W comprises, in general, a brake means or assembly for applying a braking force to the web roll 12 to place the web W under tension and a brake actuating mechanism for actuating the brake means 20 to apply a braking force to the web roll 12 to place the web under a desired tension and for respectively increasing and decreasing the braking force applied to the web roll to increase and decrease the tension placed on the web when a decrease and increase from the desired web tension occurs during operation of the press.

The brake assembly 20 is supported by one of the support stands 14 and comprises a pair of opposed brake shoes or

blocks

26, 27 for frictionally engaging a brake drum 28 fixed to the shaft 13 at one end of the web roll 12 to apply a braking force to the web roll 12 to place the web W under tension. To this end, the brake drum 28 has an annular generally V-shaped groove whose tapered or beveled sides 30, as viewed in FIG. 4, are adapted to be frictionally engaged by complementary tapered or beveled sides 31 at the inner end 32, as viewed in FIGS. 3 or 4, of the

brake shoes

26, 27. The

brake shoes

26, 27, as viewed in side elevation, each have an inner end face 33 which is arcuate and concentric with respect to the axis of rotation of the drum 28, an outer vertically extending end face 34 which is straight and planar, and opposed vertically extending side surfaces 35 which are parallel to one another and parallel to the outer end face 34. The

brake shoes

26, 27 can be made from any suitable material, such as wood.

The

brake shoes

26, 27 are carried by upwardly extending brake arms or

carriers

40, 41. The

brake arms

40, 41 are U-shaped, as viewed in cross section (see FIG. 5 and with their bottom and

side walls

42, and 43, respectively, being straight planar and extending parallel to each other. The

brake shoes

26, 27 at their outer ends are received between the legs 43 of the

brake arms

40, 41 and are respectively pivotally connected intermediate their upper and lower ends to the legs 43 of the

brake arms

40, 41 by

pivot pins

46, 47. The pivotal connection is such that the outer end faces 34 of the

brake shoes

26, 27 are spaced from the bottom 42 of the adjacent brake arm carriers -41 so that the

brake shoes

26, 27 can pivot relative to the brake arms and be self-aligning with respect to the groove of the brake drum 28 when they are moved into engagement with the latter. The sides 43 of the

brake arms

40, 41 also serve to guide the

brake shoes

26, 27 during pivotal movement relative to the

arms

40, 41. Also, suitable spacers 48 surrounding the

pivot pins

46, 47 and disposed between the

brake shoes

26, 27 and legs 43 of the

brake arms

40, 41 are preferably provided to position the

brake shoes

26, 27 between the legs 43.

It should be noted at this point that the brake shoe and brake arm construction of the present invention is a simpler and more economical construction than known brake constructions heretofore employed. These known brake constructions have included three parts, i.e., a brake arm, an arcuately extending brake shoe holder pivotally connected to the brake arm and an arcuately shaped brake shoe fixed tothe brake shoe holder. Thus, the brake construction of the present invention eliminates a part heretofore employed in known brake constructions. Also, since the outer end of the

brake shoes

26, 27 can be made planar the brake shoe construction is a more economical construction as compared to known brake shoe constructions.

The

brake arms

40 and 41 are pivotally supported for movement toward and from each other and the brake drum 28. To this end, the

arms

40 and 41 are pivotally connected at their lower end, as best shown in FIG. 5, to sleeves 50 and 51 and in a manner which prevents relative endwise movement therebetween. The

sleeves

50 and 51 freely extend through aligned openings 52 (see FIG. 3) in the sides 43 of the brake arms 40 and 41' and are threadably engaged with and supported by threaded

shafts

53 and 54, respectively. As best shown in FIG. 4, the

shafts

53, 54 are stationary and extend generally parallel to the axis of rotation of the web roll 12. The

shafts

53, 54 have one end connected with the support stand 14 and the other end connected with a cross member or brace 56 laterally spaced from the support stand 14 and provide a cantilever support for the brake means 20.

The

brake arms

40, 41 at their upper ends, as viewed in FIG. 1, are operatively connected with the brake actuating mechanism 25. The mechanism 25, in general, is effective to move the

brake arms

40, 41 and

brake shoes

26, 27 toward each other in a brake applying direction and to bias the same into engagement with the brake drum 28 With a presettable biasing force to place the web W under a desired tension. The mechanism 25 is also operable to automatically increase and decrease the braking force applied to increase and decrease the tension of the web W when a decrease or increase in the web tension from the desired web tension occurs during operation of the printing press.

The brake actuating mechanism 25 comprises a toggle device 60, as best shown in FIG. 1, interconnecting the upper ends of the

brake arms

40, 41. The toggle device 60 comprises a lever 70 which extends through a vertically extending slot in the upper end of the bottom wall 42 of the brake arm 41 and which is pivotally connected intermediate its ends to the sides 43 of the brake arm 41 by a pivot pin 71. The lever 70 at its left end is pivotally connected to one end of a turn buckle 73 by a pivot pin 74. The other end of the turn buckle 73 is threaded and is in a threaded engagement with a threaded rod or shaft 75. The rod 75 at its other end extends through a vertically extending slot at the upper end of the bottom wall 42 of the brake arm 40 and is fixed to a knob 76 having a spherical portion 76a which engages a socket like indentation in the bottom wall 42 of the brake arm 40 to form a ball and socket connection. By suitably rotating the knob 76, the

brake shoes

26, 27 can be properly positioned with respect to the brake drum 28 to compensate for wear thereof.

The lever 70 is movable in opposite directions about the axis of the pivot pin 71 and effects movement of the

brake arms

40, 41 toward each other in a brake applying direction when moved in the direction of the arrow 77. As best shown in FIG. 1, the axis of the pivot pin 74 is disposed vertically above the axis of the pivot pin 71 so that when the lever 70 is moved in the direction of the arrow 77 the knee, i.e., the pivot pin 74, of the toggle joint is moved in an upward direction, which in turn causes the

brake arms

40, 41 to be moved in a brake applying direction until the brakes 25 and 26 frictionally engage the beveled sides of the drum 28.

The lever 70 is adapted to be moved and/or biased in the direction of the arrow 77 to cause the brake shoes 25, 26 to frictionally engage the drum 28 to exert a braking force thereto to place the web W under tension by a biasing means in the form of a compression spring 80, and in a manner to be hereinafter more fully described.

The mechanism 25 further comprises a threaded rod 80a having one end pivotally connected to the right end of the lever 70, as viewed in FIG. 1, and its other end threadably engaged with one end of a turn buckle 81. The turn buckle 81 at its other end is pivotally connected to one end of a flexible linkage 82, here shown as being a flexible chain link. The other end of the flexible linkage 82 is pivotally connected to one end of a lever 83 which in turn is rotatably journalled on a sleeve 84 threadably engaged with a threaded support shaft 85. The support shaft 85 has one end connected with the support stand 14 and the other end connected with the support brace 56.

The lever 83 at its other end is pivotally connected to a turn buckle 88 which in turn is threadably engaged with one end of a threaded shaft 90. The threaded shaft 90 at its other end is threadably engaged with one end of a turn buckle 91. The other end of the turn buckle 91 is pivotally connected to one end of a lever 94, which in turn is fixed at its other end to a shaft 95. The shaft 95 rotatably supports the idler roller 16 and at its opposite ends is rotatably supported by support stands 96. The shaft 95 also carries a pair of levers 98 having one end fixed to the shaft 95. The levers 98 at their other ends rotatably support the opposite ends of the dancer roller 18.

The dancer roller 18 is biased in a web tensioning direction, as indicated by the direction of the arrow 100 in FIG. 1, by the compression spring 80 which encircles the rod 90 and has one end in abutting engagement with a member 103 fixed to one of the support stands 96 and the other end in abutting engagement with a nut 104 threadably engaged with the threaded rod 90. The rod 90 is slidably received through an opening in the member 103 and the compressive force exerted by the spring 102 can be varied by rotating the nut 104 to vary its position relative to the rod 90. From the foregoing, it should be apparent that the compression spring 80 biases the dancer roller 16 into engagement with the web W in a web tensioning direction.

As previously mentioned, the compression spring 80 also serves to move and/ or bias the

brake shoes

26, 27 into frictional engagement with the beveled sides 30 of the brake drum 28 to apply a braking force to the web roll 12. When the

brake shoes

26, 27 are in engagement with the brake drum 28, the compressive force of the spring 80 tends to move or biases the rod 90 and the turn buckle 88 toward the left, as viewed in FIG. 1, which in turn causes the lever 83 to be biased or tend to move in the direction of the arrow 106. When the lever 83 is biased so as to tend to move in the direction of the arrow 106, a downward force is exerted on the flexible linkage 82 and rod 80, which in turn biases or tends to move the lever 70 in the direction of the arrow 77. When the lever 70 is biased in the direction of the arrow 77, the brake shoes are biased into frictional engagement with the brake drum 28. From the foregoing, it should be apparent that a preset braking force is applied to the web roll by the mechanism 25 to place the web W under a desired tension.

When a decrease in the tension of the web W from the desired tension occurs during operation of the printing press, a greater amount of the force of the compression spring 80 will be transmitted via the rod 90 to the lever 83 tending to move the same in the direction of the arrow 106, since the slack in the web W reduces the force exerted by the web W on the dancer roller 18 tending to move the latter in a web tension relieving direction, as indicated by the direction of the arrow 110. This increased force exerted on the lever 83 is transmitted via the flexible link 82 and rod 80 to the lever 70 to cause the same to be biased or tend to move in the direction of the arrow 77 with a greater force. This increased biasing force exerted on the lever 70 is transmitted to the

brake shoes

26, 27 via the

brake arms

40, 41 to increase the pressure of the frictional engagement between the

brake shoes

26, 27 and the brake drum 28. When the

brake shoes

26 and 27 are biased into tighter frictional engagement with the brake drum 28, a greater braking force is applied to the web roll which in turn places the web W under a higher tension. As the slack in the web W is taken up the web W will exert a greater force on the roller 18 tending to move the same in a web tension relieving direction and in opposition to the biasing force of the spring 80 which in turn decreases the force applied to the

brake shoes

26, 27.

When an increase in the tension of the web W occurs, the dancer roller 18 is caused to be moved in a web tension relieving direction, as indicated by the direction of the arrow 110 in FIG. 1. Movement of the dancer roller 16 in this direction effects movement of the

levers

98 and 96 in a direction of the arrow 111 which in turn causes the rod to be moved toward the right in opposition to the biasing force of the spring 80. Movement of the rod 90 toward the right causes the lever 83 to be moved in the direction of the arrow 113 which in turn decreases the downward force exerted on the link 82 and allows the same to become slack. As the flexible link 82 slackens the lever 70 is free to move in the direction of the arrow 115 which in turn enables the

brake shoes

26, 27 to move outwardly slightly from the drum 28 whereby the frictional force exerted on the drum is decreased to reduce the tension placed on the web W. As the tension of the web is being decreased to its desired value the spring 80 will effect reverse movements of the parts of the mechanism 25 and thus, cause the

brake shoes

26, 27 to be moved and then biased into frictional engagement with the brake drum 28.

To enable the Web roll 12 when the web W has been completely drawn therefrom to be readily replaced by another web roll 12, the

brake shoes

26, 27 of the brake assembly 20 can be readily moved away from the brake drum 20 by merely lifting up on the knob 76 and swinging the toggle device 60 in a clockwise direction, as viewed in FIG. 1. This enables the brake arm 40 to pivot in a counterclockwise direction from the brake drum 28 and the brake arm 41 to pivot in a clockwise direction from the brake drum 28. Movement of the brake arm 41 in a clockwise direction from the brake drum 28 is permitted due to the provision of the flexible linkage 82.

The brake means 20 is also employed for adjusting the side lay of the web roll 12 between its support stands 14 to enable it to be readily positioned in proper registry with the printing cylinders of the printing press. As previously mentioned, the

brake arms

40, 41 are supported by

sleeves

50, 51 which are threadably engaged with threaded

support shafts

53, 54 extending axially of the web roll 12 (see FIG. 5). Adjustment of the side lay of the web roll is effected by rotating the

sleeves

50, 51 in the same direction. Rotation of the

sleeves

50, 51 causes the

brake arms

40, 41 and the

brake shoes

26, 27 to be moved axially of the web roll 12, which in turn causes the web roll 12 to be moved axially between the support stands 14 due to the engagement between the

brake shoes

26, 27 and the brake drum 28.

To enable the

support sleeves

50, 51 to be simultaneously rotated in the same direction to effect adjustment of the side lay of the Web roll 12, a drive means is provided. As best shown in FIG. 5, the drive means 120 comprises a pair of

sprocket wheels

121 and 122 respectively fixed to the end of the

sleeves

50, 51 adjacent the side 43 of the

brake arms

40, 41 facing toward the web roll 12. Trained around the

sprocket wheels

121 and 122 is a sprocket chain 123. Respectively fixed to the other end of the

sleeves

50, 51 are a collar 124 and a hand wheel 126. The sprocket wheel 121 and the hand wheel 126 and the sprocket wheel 122 and the collar 124 also serve to prevent relative endwise movement between the

brake arms

40, 41 and the

sleeves

50, 51, respectively.

From the foregoing, it should be apparent that by rotating the hand wheel 126 the sleeve 50 is caused to be moved relative to the threaded shaft 53 which in turn causes the brake arm 40 and brake shoe 26 to be moved relative to the shaft 53. The rotative movement of the sleeve 50 is transmitted to the sleeve 51 by the sprocket and chain connection to cause the sleeve 51 to move relative to the threaded shaft 54 and in the same direction as the movement of the sleeve 50 which in turn causes the brake arm 41 and brake shoe 27 to be moved relative to the threaded shaft 54. It should also be apparent that as a result of the threaded engagement between the

sleeves

50, 51 and

shafts

53, 54, the forces applied to the brakes when being adjusted axially relative to the

support shafts

53, 54 by the

sleeves

50, 51 are at locations annularly around the shafts such that the effective or 7 resultant forces applied coincide or substantially coincide with the axis of the

shafts

53, 54. This eliminates or minimizes any tendency of the brakes to pivot about axes transversely of the longitudinal axis of the

support shafts

53, 54 and thus, eliminates or minimizes any binding action between the brakes and support shafts.

It should also be noted that limited adjustment of the side lay of the web roll 12 can be effected without necessitating any adjustment of the relative positions of the other parts of the mechanism due to the provision of the flexibe chain link 82. As best shown in FIG. 2 the chain link 82 due to its flexible nature will cock or be disposed at an angle as the brake means 20 is being adjusted relative to its

support shafts

53, 54. If a greater or lesser chain length is required when the brake means 20 is" adjusted, the turn buckle 81 can be suitably rotated to lengthen or shorten the length of the linkage connection between the

levers

70 and 83.

From the foregoing, it should be apparent that the hereinbefore enumerated objects have been accomplished and that a new and improved web tension apparatus which is of a highly practical, simple, economical construction has been provided. Although the web tension apparatus of the present invention has been illustrated in and described herein to a somewhat detailed extent, it will be understood, of course, that the invention is not to be regarded as limited correspondingly in scope but includes all changes and modifications coming within the terms of the claims hereof.

I claim:

1. A web tensioning apparatus for tensioning a web being fed from a rotatable web roll and which comprises a brake drum operatively connected with the web roll, brake means movable toward and from said brake drum and including at least one brake shoe for frictionally engaging the brake drum to effect the braking of the web roll to tension the web being fed therefrom, an actuating mechanism operatively connected "with said brake shoe for effecting movement of said brake shoe into frictional engagement with said brake drum, support rod means extending axially of said web roll and solely supporting said brake means for adjustment axially of said support rod means, said support rod means including plural externally threaded rods, and means for effecting adjustment of said brake means axially of said support rod means, said means including plural members movable together to apply forces to said brake means at respective spaced locations such that the effective force acts substantially along the axis of said rod means whereby the adjustment can be effected with only a minimum tendency of the brake means to pivot about an axis extending transversely of the axis of said support rod means, said members for effecting adjustment of said brake means being internally threaded for engagement with said threaded support rods, said brake means being pivotally connected to said members for movement about the longitudinal axis of said rods, said brake means being adjustable axially of said rod means by relatively rotating said members and said rods.

2. A web tensioning apparatus for tensioning a web being fed from a rotatable web roll and which comprises a brake drum operatively connected with the web roll, brake means movable toward and from said brake drum and including at least one brake shoe for frictionally engaging the brake drum to effect the braking of the web roll to tension the web being fed therefrom, an actuating mechanism operatively connected with said brake shoe for effecting movement of said brake shoe into frictional engagement with said brake drum, said actuating mechanism including flexible link means having one end operatively connected with said brake shoe whereby said brake means can be moved axially of the web roll without necessitating adjustment of the relative positions of other parts of the actuating mechanism, support rod means extending axially of said web roll and solely supporting said brake means for adjustment axially of said support rod means, and means for effecting adjustment of said brake means axially of said support rod means, said means including plural members movable together to apply forces to said brake means at respective spaced locations such that the effective force acts substantially along the axis of said rod means whereby the adjustment can be effected with only a minimum tendency of the brake means to pivot about an axis extending transversely of the axis of said support rod means.

3. A web tensioning apparatus for tensioning a web being fed from a rotatable web roll and comprising brake means for applying a braking force to said web roll to tension the web being fed therefrom, said brake means including a brake arm pivotally supported for movement toward and from the web roll, said brake arm having a U-shaped cross sectional shape with straight planar bottom and side walls, a brake shoe pivotally connected to said side walls of said brake arm for movement in opposite directions relative thereto and having one end frictionally engageable with said web roll to apply a braking force thereto, said brake shoe at its end remote from said one end being planar and spaced from the planar bottom of said brake arm whereby said brake shoe can pivot relative to said brake arm and with the sides of the brake arm serving as a guide for the brake shoe, and an actuating mechanism operatively connected with said brake arm for moving said brake shoe into frictional engagement with said web roll.

4. A web tensioning apparatus for tensioning a web being fed from a Web roll rotatably supported by a pair of spaced supports and having a brake drum and comprising brake means for applying a braking force to said brake drum to tension the web being fed from the web roll, said brake means comprising first and second brake arms on opposite sides of said brake drum and first and second brake shoes carried by the first and second brake arms, respectively, said first and second brake arms being pivotally supported for movement toward and from each other and said brake drum, a brake actuating mechanism operatively connected with said brake arms for moving and biasing the brake shoes carried by the brake arms into frictional engagement with said brake drum to apply a braking force thereto, adjustable support means for supporting the brake means for movement in opposite directions parallel to the rotating axis of the Web roll, said support means comprising first and second stationary threaded shafts extending in directions substantially parallel to the axis of rotation of the web roll and first and second rotatable internally threaded members pivotally supporting said first and second brake arms and threadably engaged with said first and second shafts, respectively, and a drive means operatively connected with said first and second members for rotating the same to simultaneously move said first and second brake arms axially of the web roll to adjust the sidewise position of said web roll between said supports.

5. A web tensioning apparatus as defined in claim 4, and wherein said drive means comprises a sprocket wheel fixed to each of said first and second members, a chain trained around the sprocket wheels and means fixed to said first member for rotating the same.

6. A Web tensioning apparatus, as defined in claim 5, and wherein said means for rotating said first member is a handwheel.

7. A web tensioning apparatus, as defined in claim 4, and wherein said actuating mechanism includes flexible link means operatively connected with said brake means, said flexible link means enabling said brake means to be moved axially of the web roll without necessitating adjustment of the relative positions of other parts of the actuating mechanism.

8. A web tensioning apparatus for tensioning a web being fed from a Web roll rotatably supported by a pair of spaced supports and having a brake drum and comprising brake means for applying a braking force to said brake drum to tension the web being fed from the web roll, said brake means comprising first and second brake arms on opposite sides of said brake drum and first and second brake shoes carried by the first and second brake arms, respectively, said first and second brake arms being pivotally supported for movement toward and from each other and said brake drum, adjustable support means for supporting the brake means for movement in opposite directions parallel to the rotating axis of the web roll for adjustably positioning the web roll sidewise between said supports, a brake actuating mechanism operatively connected with said brake arms for moving and biasing the brake shoes carried by the brake ar-ms into frictional engagement with said brake drum to apply a braking force thereto, said actuating mechanism including flexible link means fixedly connected at one end with said brake means so that said one end moves with said brake means upon adjustment thereof, said flexible link means enabling said brake means to be moved axially of said web roll without necessitating adjustment of other parts of the actuating mechanism.

9. A web tension control apparatus for controlling the tension of a web being fed fom a rotatable web roll having a brake drum and comprising brake means for applying a braking force to said brake drum of said web roll to tension the web being fed' therefrom, said brake means comprising first and second brake arms on opposite sides of said brake drum and first and second brake shoes carried by the first and second brake arms, respectively, said first and second brake arms being pivotally sup ported at one end for movement toward and from each other and said brake drum, a brake actuating mechanism operatively connected with said brake arms for moving and biasing the brake shoes carried by the brake arm to- Ward each other and into frictional engagement with said brake drum to apply a braking force thereto, said brake actuating mechanism comprising first means for connecting said brake arms together at their other end, said first means including a first lever pivotally connected to said second brake arm for movement in opposite directions and a link having one end pivotally connected with one end of said lever and its other end releasably connected with said first brake arm, said pivotal connection between said link and lever being disposed slightly above the pivotal connection between said lever and said second brake arm whereby said lever causes said brake arms to move toward each other when moved in one direction, a roller engageable with said' web, and spring means operatively connected with said roller and said lever for biasing said roller in a web tensioning direction and for biasing said lever in said one direction.

10. A web tension control apparatus, as defined in claim 9, and wherein said actuating mechanism includes a second lever supported for movement in opposite directions and flexible link means having its opposite ends connected with said first and second levers, the biasing force of said spring means being transmitted from said second lever through said flexible link means to said first lever, said flexible link means allowing said second brake arm to be moved away from said brake drum when said first means is released from said first brake arm.

11. A web tensioning apparatus, as defined in claim 8, and wherein said flexible link means is a chain.

12. A web tensioning apparatus for tensioning a web being fed from a rotatable web roll comprising a brake unit for applying a frictional force to an annular brake drum mounted on a rotatable support rod for the web roll to tension the web being drawn from the web roll, said brake unit including a brake shoe carrier having a pair of arms located on opposite sides of said brake drum and adapted to be pivoted toward and from said brake drum, each of said brake arms having a generally U- shaped cross sectional configuration with straight planar bottom and side wall sections, a brake shoe disposed between and movably connected to said side wall sections of each of said brake arms for movement relative to the associated brake arm, each of said' brake shoes having an arcuately shaped end which is adapted to cooperbly engage the annular brake drum to apply a braking force thereto, each of said brake shoes at its end remote from said arcuate end being straight and planar and spaced from the planar bottom of the associated one of said brake arms to enable said brake shoes to move relative to the associated brake arm with the sides of the associated brake arm serving as a guide for the brake shoe, and an actuating mechanism operatively connected with said brake arms for pivoting said brake arms toward the brake drum to bring said brake shoes into frictional engagement with said brake drum to thereby retard rotation of said web roll.

13. A web tensioning apparatus as set forth in claim 12 further including a pair of support members each of which extends axially of said web roll for supporting an associated one of said brake arms, and means for elfecting adjustment of said brake arms axially of said support members, said means including plural members movable together to apply forces to said brake arms at respective spaced locations such that the effective force acts substantially along the axis of said support members whereby the adjustment of said brake arms can be effected with only a minimum tendency of the brake arms to pivot about an axis extending transversely of the axis of said support members.

References Cited UNITED STATES PATENTS 701,220 5/1902 Odgers 188219.6 1,388,342 8/ 1921 Hopkins 242-75.43 1,420,274 6/ 1922 Miller 188219.6 1,829,337 10/1931 Brueshaber 242-7543 NATHAN L. MINTZ, Primary Examiner.