Apparatus and method for applying an elongated tab to a moving substrate

An applicator (10) for applying a string or tape (72) coated with a thermoplastic adhesive to a moving substrate (14) is the subject of this patent application. The applicator (10) includes a first roll (28) about which the string (72) is fed. Thereafter, the string (72) is led over a second roll (30). The string (72) is, successively looped about both of the rolls (28, 30) a number of times. One of the rolls (28) is heated by use of a plurality of heating elements (26) embedded in a casting (24) surrounding the roll (28). The second roll (30) is pivotable about an axis and in a plane generally parallel to an axis of elongation of the first roll (28). Loops of the string (72) can, thereby, be spaced axially along the rolls (28).

TECHNICAL FIELD 
The invention of the present application broadly deals with packaging for 
bulk commodities such as soaps and detergents. More narrowly, however, the 
invention is directed to the application of a tab, by which a subsequently 
formed package can be opened, to a moving board or kraft paper substrate 
used in forming the packaging. In a preferred embodiment, the invention is 
directed to an apparatus for applying a thermoplastic adhesive 
impregnated, elongated tab to the moving substrate. 
BACKGROUND OF THE INVENTION 
Various products commercially available are sold in large capacity, board 
or kraft paper packaging typically characterized as an "economy size" 
packaging. Illustrative of these types of products are soaps, detergents, 
etc. 
Although smaller packagings have portions thereof which are perforated so 
as to be able to have the perforated portion pushed inward in order to 
create a discharge aperture, larger capacity packagings commonly are 
opened by drawing a tear tab along at least a portion of the periphery of 
the packaging box in order to, for example, provide a hinged lid providing 
access to the contents carried therein. 
Such larger capacity packagings are typically made from folding carton 
board stock or heavy kraft paper. The board stock or paper is run over 
rollers or between nips formed between pairs of rollers in an "in-machine" 
direction. As the board stock or kraft paper passes a particular position, 
apparatus at the position feeds a tab string or tape material from a spool 
onto the moving substrate. The tab material is impregnated with a 
thermoplastic adhesive which, prior to the tab being applied to the moving 
substrate, is heated to a temperature at which it will become soft enough 
so that, when it is brought into engagement with the substrate, it will 
wet-out sufficiently to allow bonding of the tab to the substrate. 
Various devices in the prior art have utilized heated rolls or wheels to 
effectuate the heating, and consequent softening, of the adhesive 
impregnating the tab. U.S. Pat. No. 3,617,422 issued to John Rene Paulson 
on Nov. 2, 1971 illustrates one particular hot wheel applicator. 
Structures of this type, however, have a number of inherent problems. A 
significant limitation upon the productivity of a facility manufacturing 
packaging as previously described is the speed at which the web substrate 
moves. The speed of the substrate is, however, limited by the speed at 
which the tab can be fed into engagement therewith and, in turn, the speed 
at which the thermoplastic adhesive can be brought to a desired 
temperature at which the tab can be satisfactorily bonded to the 
substrate. The governing manufacturing limitation, therefore, becomes the 
speed at which the adhesive is brought to its application temperature. 
In conducting manufacturing operations, the web substrate can be made to 
travel at speeds between 500 feet per minute and 1000 feet per minute. If 
a heating wheel such as that illustrated in the Paulson patent were used 
to heat the adhesive prior to applying the tab to a substrate moving this 
fast, the adhesive could not be brought to a sufficiently high temperature 
in order to form a satisfactory bond between the tab and the substrate. 
The case is similar with other wheel and roll type heating applicators. One 
type of applicator commercially available utilizes a heating roll having a 
diameter of 16 inches. When such a roll is utilized to apply a tab to a 
substrate moving at 500 feet per minute, a particular segment of the tab 
is in engagement with, and absorbing heat from, the roll for a maximum of 
approximately 0.4 seconds. This time period is inadequate to wet-out most 
adhesives available for this application in order that a satisfactory bond 
be formed. 
In reviewing the Paulson patent, one notices that, with that structure, the 
adhesive which is being heated is in engagement with the heating roll 
about only 75 to 80% of the circumference of the roll. The period of time 
during which the adhesive is heated, or dwell time, as it is referred to, 
can be increased by causing the adhesive to engage the heating roll so 
that a larger percentage of the circumferential surface of the roll will 
provide heat to the adhesive. Because of the engagement of the heated roll 
by the moving substrate, however, 80% of the circumferential surface is 
the approximate practical limit which can be made to be engaged by the 
adhesive. 
Another possible solution to the problem is increasing the size of the 
heating roll in order to increase dwell time. This solution, however, also 
proves to be impractical. The 16 inch diameter wheel currently used in 
some structures is approaching the maximum size which can practicably be 
used, and, because of space limitations, use of a larger wheel would 
frequently be precluded. 
Since the heat which is transmitted from the heated wheel to the 
impregnated tab is proportional to the temperature differential which 
exists between the wheel and the adhesive, one other possible solution is 
suggested. This solution would increase the temperature of the wheel to a 
level above that to which the adhesive is desired to be heated. 
Consequently, the adhesive would be provided with sufficient heat in order 
to insure adequate bonding even if the dwell time were as little as 0.4 
seconds. 
This solution, however, presents its own problems. Non-uniform bonding 
would be effected should the speed of the substrate in the "in-machine" 
direction be varied. Even more significantly, if movement of the substrate 
is terminated, the tab might become overheated. Where a tab having a 
thermoplastic core such as polyester is used, not only might the adhesive 
be melted, but the core also might be melted to the point where the tab 
breaks. 
A further reason why it is not desirable to heat the wheel above the 
temperature to which the adhesive should be heated is the consequent 
reduction in service life of the equipment because of the higher operating 
temperatures. With such elevated temperatures, the equipment is subject to 
a shorter life. For these reasons, therefore, elevating the heating 
element to a temperature no higher than that to which the adhesive is 
desired to be raised is considered desirable. 
It is to these problems and shortcomings in the prior art that the 
invention of the present application is directed. It provides a structure 
by which a tab, to be applied to a moving web substrate, can be heated 
sufficiently in order to insure adequate bonding to the substrate, but 
without overheating the tab to a point at which it will break. 
Additionally, it allows the tab to be heated uniformly along its length 
regardless of the speed at which the substrate is made to move in an 
"in-machine" direction. 
SUMMARY OF THE INVENTION 
The invention of the present application is a method for applying an 
elongated tab such as a string or tape to a moving web. The string or tape 
is coated with a thermoplastic adhesive, and it is an object of the method 
to bring the temperature of the adhesive to a point so that it becomes 
sufficiently pliant whereby, when the tab is applied to the moving web, 
satisfactory bonding of the tab to the web will be accomplished. In 
addition to a primary heating roll, a second roll having an axis spaced 
from the rotational axis of the heating roll is provided. The elongated, 
flexible tab is fed from a storage position, such as one in which it is 
wound on a spool, partially about the primary heating roll and, 
thereafter, around the second roll. The flexible tab member is 
successively looped about both of the rolls with each of the loops 
extending about both rolls. 
The method can include a step of pivoting the second roll in a plane 
generally parallel to the axis of the primary heating roll and to 
positions at which the axes are out of parallel alignment. By so pivoting 
the second roll, the loops of the tab will be spaced from one another 
along the axes of the rolls. 
The invention also includes a device for effectuating the method. The 
device includes a first elongated element, or roll, which is disposed for 
rotation about its axis of elongation. A second element, or roll, which is 
at least partially axially coextensive with the first element is provided. 
The second element is configured for pivoting, which pivoting defines a 
plane generally parallel to the axis of the first roll. When viewing the 
plane from a direction generally transverse to the orientation of the 
plane, the pivoting of the second element causes the variation of size of 
an angle formed between the axes of the two elements or rolls. At least 
one of the rolls, preferably that which is not pivotally mounted, is 
heated to a temperature to which it is desired to raise the thermoplastic 
adhesive which impregnates the tab. The tab is successively looped about 
both of the rolls to absorb heat from the heated roll as it passes 
thereabout and to promote equalization of the temperature of the adhesive 
throughout the total adhesive impregnation as the tab passes between 
rolls. 
A preferred embodiment can include a third roll which is disposed for 
rotation about an axis of elongation generally parallel to the axis of the 
first roll. The third roll has an outer peripheral surface which is 
frictionally engaged by the moving web substrate. Transmission means can 
be provided to translate the rotational motion imparted to the third roll 
by the web, to the first roll. The transmission means can include 
appropriate gears, sprocket wheels, and intermediate elements in order to 
allow the first roll to rotate, preferrably in a direction opposite that 
in which the third roll rotates or, if desired, in a consistent direction. 
The first roll can be supported in a cantilever fashion from a gear box 
which houses the various gears, sprocket wheels, etc. which accomplish the 
transmission of the rotational motion from the third roll to the first 
roll. An end of the first roll which is supported within the gear box can 
have an annular groove formed therein and about the axis of rotation of 
the roll. A temperature sensing probe can extend into the groove to sense 
the temperature to which the roll is being heated. The probe can transmit 
the information sensed to a controller which regulates a plurality of 
heating elements surrounding the roll. If the roll is not being 
sufficiently heated in order to raise the thermoplastic adhesive to a 
satisfactory bonding temperature, the controller will be actuated to 
increase the temperature of the heating elements providing thermal energy 
to the roll. 
Conversely, if the temperature of the roll is too high, the controller will 
be actuated to decrease the temperature to which the roll is heated by the 
heating elements. Consequently, overheating of the adhesive and/or a 
possible breaking of the tab is precluded. 
The invention is thus an improved method and device for applying a 
thermoplastic impregnated tab to a moving web substrate in order to 
achieve a more satisfactory bonding of the tab to the substrate. More 
specific features of the invention and advantages obtained in view of 
those features will become more apparent with reference to the detailed 
description of the invention, claims, and appended drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings wherein like reference numerals denote like 
elements throughout the several views, a preferred embodiment of the 
invention and an alternative structure for a drum portion of a heated roll 
in an applicator constructed in accordance with the invention are 
illustrated. Referring to FIGS. 1, 2, and 3, and particularly to FIG. 3, a 
preferred embodiment of an applicator 10 in accordance with the present 
invention is shown as being mounted to a structural support beam 12 
fixedly positioned at a location relative to the passage of a moving web 
substrate 14 such as board stock or kraft paper. The applicator 10 is 
attached to the structural support beam 12 by a clamp bracket 16. The 
operating structure of the applicator is carried by the bracket 16 and is 
pivotally mounted as at 18 to pivot about a pair of cone shaped bearings 
20. A toggle clamp mechanism 22 is provided to move the applicator 10, 
selectively, into, and out of, engagement with the moving web substrate 
14. 
The operating portions of the applicator 10 include an aluminum casting 24 
having a plurality of heating elements 26 cast integrally therewith, a 
first roll 28, enclosed by the casting 24, a second roll 30 mounted atop 
the casting 24, a third roll 32, and a gear box 34. The first and third 
rolls 28, 32 are fixedly attached to ends of axels 36, 38 extending in a 
cantilever fashion from the gear box 34. The axels 36, 38 are supported by 
bearings 40 at respective sidewalls 42, 44 of the gear box 34. The axels 
36, 38 have hollow shafts which are designed to minimize the transfer of 
heat from heated drum portions 46, 48 of the rolls 28, 32 to the bearings 
40. 
The first roll 28 is keyed to the axel 36 with which it rotates by a pin 50 
inserted through an aperture 52 formed in an inner hub portion 54 of the 
roll 28 and an aperture 56, in registration with the aperture 52 in the 
hub portion 54, in a sleeve 58 keyed to the axel 36. At its end opposite 
the gear box 34, the first roll carries a removeable annular collar 60. 
The collar is affixable to the drum portion 46 of the roll 28 by 
appropriate means such as screws 62. The collar 60 has a track 64 defined 
between axially spaced inner and outer flanges 66, 68. As shown in FIG. 3, 
the preferred embodiment of the apparatus 10 includes a track 64 which 
does not have any ribs formed thereon. As seen in FIG. 5, however, an 
alternative embodiment of the invention contemplates a track 64 having 
annular ribs 70 to assist in maintaining separation of loops of a 
flexible, elongated string or tape 72 having portions thereof extending 
about the first roll 28. 
As best seen in FIG. 3, the aluminum casting 24 having the heating elements 
26 embedded therein encircles the drum portion 46 of the first roll 28 and 
has an inner surface 74 closely spaced from an outer peripheral surface 76 
of the roll 28. The heating elements 26 are controlled by a controller 
(not shown) through a cable 78. The controller can be a solid state 
electric controller having wires running through the cable 78 to the 
heating elements 26 in the casting 24. 
The casting 24, roll drum 46, and collar 60 are all made of heat conductive 
material so that heat generated at the heating elements 26 will pass to 
the track surface of the collar 60. 
The first roll 28 has, formed in an axial end thereof proximate the gear 
box 34, an annular groove 80. A temperature sensing probe 82 carried by 
the gear box 34 is mounted for extension into the groove 80. As the first 
roll 28 is made to rotate on its axel 36, the probe 82 will remain in the 
groove 80 regardless of the portion of the roll 28 positioned relative 
thereto. 
The probe 82 senses the temperature to which the drum 46 is being heated by 
the heating elements 26. The probe 82, in turn, actuates the controller to 
adjust the amount of thermal energy which is generated by the heating 
elements 26. The string or tape 72 which is extended around the collar 60 
of the first roll 28 is impregnated with a thermoplastic adhesive in order 
to effect bonding of the string or tape 72 to the moving web substrate 14 
to which it is applied. It is the heat generated by the heating elements 
26 and transferred to the collar 60 which softens the adhesive in order to 
effect bonding to the substrate 14. If the temperature to which the 
adhesive is heated is not sufficiently high, satisfactory bonding will not 
be accomplished. If, on the other hand, the temperature becomes too high, 
the adhesive might melt off, and, in cases where particular types of 
cores, such as thermoplastic polyester cores are used to carry the 
adhesive, the core may break, interrupting application operations. The 
controller, therefore, in response to the temperature sensed by the probe 
82, causes the heating elements 26 to produce, essentially, a constant 
temperature. 
A second roll 30 is surrounded by a roll housing 84 for rotation about an 
axis of elongation thereof. The roll 30 is shown as having a portion 86 
extending from the housing 84 and above the first roll 28 so that the 
portion 86 is axially coextensive therewith. The roll 30 is supported in a 
cantilever fashion within a bearing sleeve 88 extending from housing 84 on 
a side opposite that from which portion 86 of roll 30 extends. A bearing 
(now shown) is held within the bearing sleeve 88, and roll 30 is supported 
by the bearing. 
As best seen in FIG. 1, the string or tape 72 is fed downwardly from a 
storage spool or other similar structure (not shown) around a portion of 
the annular collar 60 of the first roll 28 and looped up over portion 86 
of the second roll 30. The string or tape 72 is, thereafter, again fed 
about the first roll 28 and back over portion 86. 
In the preferred embodiment of the invention, successive loops of the 
string 72 are spaced in an axial direction proceeding outwardly from the 
casting 24. In the embodiment shown in FIG. 5, a first loop would be 
seated in an innermost of the channels 90, the second in the second 
innermost channel 90, etc. 
As illustrated in the figures, the remote end of the portion 86 of the 
second roll 30 does not have a flange as does the collar 60 of the first 
roll 28. Consequently, the second roll 30 extends axially beyond the 
collar 60 of the first roll 28, and axial movement of the loops is limited 
by the outer flange 68 of the first roll 28 alone. In one structure of the 
apparatus, the collar 60 of the first roll 28 has been given a dimension 
of two and one half inches, while the portion 86 of the second roll 30 
which is axially coextensive with the collar 60 has been given a dimension 
of 2.87 inches. It will be understood, however, that these dimensions are 
not exclusive and are only those used in one particular structure. 
Dimensions may vary depending upon circumstances and particular 
applications. 
Similarly, although the collar 60 illustrated in FIG. 5 is shown as having 
only five channels 90 formed therein, it will be understood that numbers 
of channels 90 in excess of five are specifically contemplated. In fact, 
in the preferred embodiment of the invention wherein ribs 70 are not 
provided in the track 64, the string 72 can be looped about the first and 
second rolls 28, 30 as many as approximately 10 times. It is understood, 
therefore, that, when such a number of loops are necessary, an embodiment 
as illustrated in FIG. 5 would provide a similar number of channels 90. 
The second roll 30 is disposed for pivoting about a generally vertically 
extending axis and in a generally horizontal plane parallel to the axis 
about which the first roll 28 rotates. A circular base 92 of the roll 
housing 84 is rotatably held by a pair of shoes 94 mounted to casting 24 
to accomplish this disposition. As seen in FIG. 2, the axis of rotation of 
the second roll 30 can be made to diverge from the axis of the first roll 
28 so that the two axes, as viewed in a direction generally perpendicular 
to the plane defined by the axis of the second roll 30 as the second roll 
30 pivots, form a variable sized angle therebetween. Typically, the angle 
of divergence of the axis of the second roll 30 will vary between 
5.degree. and 30.degree. depending upon the number of loops of the string 
72 about the rolls 28, 30. 
Referring now to FIGS. 6 and 7, and, first, FIG. 7, a small angle of 
divergence is illustrated schematically. The solid lines and dotted lines 
are used to illustrate the loops of the string 72 as they extend about the 
two rolls 28, 30. The string 72 engages the first roll 28 at a point 
indicated by the reference numeral 96 and passes beneath the first roll 28 
in a plane generally transverse to the axis of the roll 28. Thereafter, as 
illustrated by the solid line emanating from the point identified by 
reference numeral 98, it will pass over the second roll 30 and will seek 
to position itself in a plane generally transverse to the axis of the 
second roll 30. 
That portion of the run of a loop extending between points 98 and 100, that 
point at which the loop will re-engage first roll 28, which actually 
engages second roll 30 will, in fact, lie in a plane generally transverse 
to the axis of the second roll 30. Consequently, geometry dictates that 
that portion of the run of the loop extending between points 98 and 100 
which is actually in engagement with second roll 30 will form an angle 
relative to the run of the loop extending between points 96 and 98 which 
is equal to the angle of divergence of the axis of second roll 30 from the 
axis of first roll 28. 
Construction of a test structure, however, has revealed that that portion 
of the loop which is in engagement with neither the first roll 28 nor the 
second roll 30 will define a plane which is oblique with respect to the 
axes of both rolls 28, 30. As the string 72 departs from the surface of 
first roll 28 at point 98, it will diverge from the dotted line extending 
between points 96 and 98 at an angle somewhat smaller than the angle 
formed between the line indicating the portion of the loop in engagement 
with second roll 30 and the dotted line extending between points 96 and 
98. 
In any case, however, the point 100 at which the string 72 re-engages the 
first roll 28 will, therefore, be spaced axially outwardly from the point 
96 at which it, in the immediately previous coil, engaged first roll 28. 
As can be seen, therefore, each successive loop will be spaced axially 
somewhat from the immediately previous loop, and the distance of spacing 
will be a function of the angle of divergence of the axis of the second 
roll 30 from that of the first roll 28. 
Referring then to FIG. 6, the axes of the first and second rolls 28, 30 are 
shown with a greater angle of divergence. As can be seen, the distance 102 
is greater than the distance 104 between loops in FIG. 7. 
It will be understood, of course, that, although only four loops are shown 
in FIGS. 6 and 7, any number of loops are contemplated by the invention. 
As previously stated, in one particular application, approximately 10 
loops of the string 72 are made about the rolls 28, 30. As will be 
apparent, however, the degree to which the second roll 30 can be pivoted 
and, consequently, the number of loops is limited by the axial length of 
the collar 60 of the first roll 28, assuming that the portion 86 of second 
roll 30 extends beyond the end of collar 60. 
As best seen in FIGS. 2 through 4, the bearing sleeve 88 of the second roll 
30 has a downwardly extending boss 106. A threaded shank 108 having a pair 
of annular flanges 110 extending generally normal to the longitudinal axis 
of the shank 108 is disposed for longitudinal movement in a plane 
generally parallel to the plane defined by the pivoting of the second roll 
30. The shank 108 is spaced at an appropriate distance from the second 
roll 30 so that the boss 106 is held between the flanges 110 of the shank 
108. The shank 108 is threaded into an internally threaded bore formed in 
a member 112 attached to the casting 24. Either end of the shank 108 
includes a slot 114 for screwdriver adjustment. As the shank 108 is moved 
longitudinally, the boss 106 will be carried by the flanges 110 and moved 
axially with respect to the shank 108. Since the boss 106 is spaced from 
the pivot point of the second roll 30, as it is urged axially with respect 
to the shank 108, the second roll 30 will be made to pivot. 
If desired, appropriate indicia (not shown) can be provided on the casting 
24 in order to indicate the degree of angling of the second roll 30 with 
the shank 108 in particular locations relative to the indicia. 
Means can be provided for directing the string 72, after it has been looped 
successively a number of times about the first and second rolls 28, 30, 
into engagement with the moving substrate 14. A third roll 32 having an 
axis generally parallel to the axis of the first roll 28 and being closely 
proximate the first roll 28 can be utilized for this purpose. The third 
roll 32 is rigidly attached to an axel 38 rotatably supported by a pair of 
bearings 40, each supporting the axel 38 at one of the sidewalls 42, 44 of 
the gear box 34. Since a portion of the third roll 32 is closely proximate 
that portion of the casting 24 in which the heating elements 26 are 
embedded, this axel 38, as in the case of the axel 38 by which the first 
roll 28 is supported, can be hollow in order to minimize heat transmission 
to the bearings 40. 
As best seen in FIGS. 1 and 3, the string 72, after its last loop about the 
first and second rolls 28, 30, can be fed about a portion of the outer 
peripheral surface 116 of the third roll 32 in a direction opposite that 
in which the coils of the string 72 are looped about the first and second 
rolls 28, 30. Thereafter, it can be drawn into a nip 118 formed between 
the third roll 32 and the moving substrate 14. 
It will be observed that, since the third roll 32 is closely proximate a 
portion of the casting 24 in which the heating elements 26 are embedded, 
it will maintain the thermoplastic adhesive at the desired bonding 
temperature until the string 72 is actually applied to the substrate 14. 
In alternative structures, the third roll 32 can be provided with an 
independent heating source so that, if the temperature to which the 
substrate 14 can be actually subjected is less than that to which the 
adhesive is desired to be brought, heat can be applied to the adhesive 
until it is engaged with the substrate 14, but at a temperature lower than 
that provided by the first roll 28. 
Since the outer peripheral surface 116 of the third roll 32 is frictionally 
engaged by the moving substrate 14, the third roll 32 will rotate at a 
speed commensurate with the speed at which the substrate 14 moves in an 
"in-machine" direction. If the string 72 were strong enough, it, 
theoretically, would function as a continuous belt to effect rotation of 
the first and second rolls 28, 30. In order, however, to reduce tensions 
on the string or tape 72, transmission means can be provided in order to 
effect rotation of the first roll 28 in response to rotation of the third 
roll 32. A jack shaft 120 can be disposed within the gear box 34 for 
rotation about an axis generally parallel to the axis of elongation of the 
axel 38 carrying the third roll 32. A gear 122 can be keyed to the jack 
shaft 120 and be in engagement with a similar gear 124 rigidly keyed to 
the axel 38 carrying the third roll 32. The jack shaft 120 will, thereby, 
be made to rotate in a direction opposite that in which the third roll 32 
rotates. 
Spaced axially on the jack shaft 120 from the gear 122 is a sprocket 126 
wheel which is axially coextensive with a second sprocket wheel 128 
mounted to the axel 36 supporting the first roll 28. These sprocket wheels 
126, 128 are rigidly keyed to their respective shaft 120 and axel 36, as 
is true of the gears 122, 124 previously discussed. A continuous chain 
130, compatible with the teeth of the sprocket wheels 126, 128 is made to 
extend about the wheels 126, 128. Since the wheels 126, 128 are rigidly 
keyed to their respective shaft 120 and axel 36, the rotation of the jack 
shaft 120 will be transmitted to the axel 36 supporting the first roll 28. 
This rotation of the first roll 28 will be in a direction similar to that 
of the jack shaft 120 and opposite that of the axel 38 supporting the 
third roll 32. 
In FIG. 1, the substrate 14 is illustrated as moving from left to right 
with respect to the third roll 32. With such a movement, the third roll 32 
is made to rotate in a counterclockwise direction. Because of the 
configuration of the first and second rolls 28, 30, it is desirable that 
they always rotate in a clockwise direction. With the particular gear and 
sprocket wheel configuration as previously discussed, however, the first 
and second rolls would be driven in a counterclockwise direction if the 
substrate were made to move from right to left as viewed in FIG. 1. A 
simple adaptation can be made if the applicator 10 is to be used with a 
substrate 14 moving thusly. The gear 124 keyed to the axel 38 supporting 
the third roll 32 can be removed and replaced with a sprocket wheel (not 
shown) made axially coextensive with the sprocket wheels 126, 128 on the 
jack shaft 120 and the axel 36 supporting the first roll 28. A longer 
chain can be made to extend about all three sprocket wheels so that the 
rotation of the third roll axel 38 is transmitted directly to the first 
wheel axel 36 and in a consistent direction. The sprocket wheel 126 keyed 
to the jack shaft 120, in such a configuration, would merely serve a 
tensioning function for the chain. As seen in FIGS. 3 and 4, a strut 132 
supporting the jack shaft 120 can be mounted to the axel 38 supporting the 
third roll 32 and pivoted about the axis thereof. An arcuate slot 134 is 
provided in the end of the strut 134, and the slot 134 can be such that it 
is always in registration with a threaded bore provided in one of the 
sidewalls 42 of the gear box 34. A screw 136 can be tightened into the 
bore in order to hold the strut 132 in a desired orientation with respect 
to the bore. In an embodiment wherein rotational motion of the third roll 
32 is transmitted directly to the first roll 28 by a chain, the chain can 
be tensioned by pivoting the strut 132 so that the jack shaft 120 is out 
of linear alignment with the axels 36, 38 of the first and third rolls 28, 
32. 
Although numerous characteristics, features, and advantages of the 
invention have been set forth in the foregoing description by utilizing 
specific structural examples, it will be understood that this disclosure 
is only illustrative. Changes may be made in details, particularly in 
matters of shape, size and arrangement of parts without exceeding the 
scope of the invention. The invention's scope is, of course, defined by 
the language in which the claims are expressed.