Manufacture of valves for inflatable articles

Valve making apparatus heat seals valve films together, and cools the resulting product web. Valves are preferably formed in two side-by-side serial arrays, with each operation of a valve die forming multiple balloon valves, including a portion of a balloon valve to be completed on a subsequent operation of the sealing die. A tension control and web conveyor are also disclosed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to the manufacture of inflatable articles 
such as toy balloons, and in particular to the manufacture of so-called 
"self-sealing" valves used therein. 
2. Description of the Related Art 
Over the years, non-latex toy balloons have become increasingly popular, 
requiring increasingly larger production quotas to meet customer demand. 
An important component of typical non-latex toy balloons offered for sale 
today is the so-called "self-sealing" valve. Examples of "self-sealing" or 
"flat" valves are given in U.S. Pat. Nos. 4,674,532; 4,708,167; and 
4,850,912. In addition to toy balloons, flat valves are used in inflated 
packages, waterbags, or similar devices typically made from plastic film. 
In its simplest form, the valve comprises a flattened hollow tube of 
readily flexible plastic film. The valve is positioned in the interior of 
the toy balloon, with the inlet end located in the neck of the balloon. 
When filling of the balloon is desired, gas pressure is introduced into 
the interior of the balloon, through the hollow tubular passageway of the 
valve. As the balloon approaches its final, inflated state, internal 
pressure developed within the balloon acts to compress the flat valve. 
This compressing pressure is easily overcome by inflating gas pressures 
transmitted through the valve. However, when inflating pressure is removed 
from the valve, internal pressure of the balloon causes the flat valve to 
quickly collapse, thus preventing gas within the balloon from escaping. 
One manufacturer of flat valves has provided serial arrays of valves which, 
when rolled, provide a convenient supply roll of flat valves to 
manufacturers of toy balloons or other pressure-containing film articles. 
The valves are formed one at a time using a heat sealing die to define the 
lateral, outside edges of the valve. The valve film is conveniently 
provided by a single continuous roll of valve film folded in half along 
its longitudinal centerline to register two layers of valve film in 
preparation for the heat sealing operation. The folded edge of the valve 
film lies along the inlet (or outlet) ends of the valve, and must be 
trimmed away so that access can be gained to the interior valve passageway 
formed by the sealing die. 
Improvements in speed and economy of manufacture are still being sought. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide apparatus for 
manufacturing self-sealing valves. 
Another object of the present invention is to provide apparatus of the 
above-described type with improved unwinding control. 
A further object according to principles of the present invention is to 
provide apparatus of the above-described type having improved throughput 
capacity. 
These and other objects of the present invention are provided in apparatus 
for making toy balloon valve products and other inflatable articles, 
comprising: 
a supply of a web including overlying first and second valve films, with 
the web comprising first and second web portions in serial succession; 
a workstation whereat valve products are made from the web; 
conveyor means actuable by a conveyor control signal for conveying the web 
past the workstation; 
sealing means at the workstation, actuable by a sealing control signal for 
heating the web to seal the first and the second valve films together to 
form valve products including at least one toy balloon valve; 
cooling means at the workstation, actuable by a cooling control signal for 
cooling the web, including a heat exchange surface movable into and out of 
engagement with the valve product; and 
control means for sending a conveyor control signal to the conveyor means 
for moving the first portion of the web containing a first valve product 
past the sealing means and for moving the second portion of the web to the 
sealing means, for sending a sealing control signal to the sealing means 
for sealing the first and the second valve films of the second portion of 
the web together to form another valve product in serial succession with 
the first valve product and for sending a cooling control signal to the 
cooling means for cooling the web. 
Other objects of the present invention are provided in apparatus for making 
toy balloon valve products, comprising: 
a supply of a web including overlying first and second valve films, with 
the web comprising first and second web portions in serial succession; 
a workstation whereat valve products are made from the web; 
conveyor means actuable by a conveyor control signal for conveying the web 
past the workstation; 
seating means at the workstation, actuable by a sealing control signal for 
heating the web to seal the first and the second valve films together to 
form a valve product comprising at least one entire balloon valve in 
serial succession with an incomplete portion of at least one other balloon 
valve; and 
control means for sending a conveyor control signal to the conveyor means 
for moving the first portion of the web containing a first valve product 
past the sealing means and for moving the second portion of the web to the 
sealing means, for sending a sealing control signal to the sealing means 
for sealing the first and the second valve films of the second portion of 
the web together to form a second valve product, including forming a 
complete valve with the incomplete part of the first portion. 
Further objects of the present invention are provided in a web supply with 
multiple tension adjustments, comprising: 
spool means for storing a supply of web to be unrolled; 
rotational mounting means for mounting the spool means for rotation; 
a brake disk attached to one of the spool means and the rotational mounting 
means for rotation therewith; 
caliper means for frictionally engaging the brake disk; 
a double ended brake arm; 
a dancer roller for engaging the web, mounted at one end of the brake arm; 
arm mounting means for pivotally mounting the brake arm adjacent the 
caliper means; 
weight means mounted for movement along the brake arm; and 
connecting rod means mounted adjacent the other end of the brake arm, 
including a connecting rod coupled to the caliper means through a 
resiliently compressible bias means. 
Other objects of the present invention are provided in a method for making 
a continuous series of toy balloon valves, comprising: 
providing first and second valve films; 
overlying one of the first and the second valve films with the other; 
provide a sealing die having die portions for sealing the first and the 
second valve films together so as to form at least one complete valve and 
an incomplete part of another valve; 
advancing the valve films adjacent the sealing die; 
sealing the valve films of the first portion together with the sealing die; 
advancing second portions of the valve films adjacent the sealing die; and 
sealing the second portions of the web together with the sealing die so as 
to form a complete valve with the incomplete part of the first portion.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, and initially to FIGS. 1-5, a valve making 
machine is generally indicated at 10. The machine includes an inlet end 12 
and an outlet end 14. Supply rolls 16, 18 of plastic films 32, 34, such as 
blended polyethylene compositions or the like, are located at the inlet 
end. The rolls 16, 18 are supported by a frame generally indicated at 20. 
Together, the films 32, 34 make up a web that is processed by machine 10 
to produce a variety of valve products. A side-by-side pair of product 
rolls 24, 26 are also supported by frame 20 at the outlet end 14 of the 
machine. A workstation generally indicated at 30 is located at the middle 
of the machine. 
Valve films 32, 34 are drawn in dash line in FIGS. 2 and 3 for clarity of 
illustration. As will be seen herein, the valve films 32, 34 are joined 
together at station 30 to form a product web 36, which is shown in greater 
detail in FIG. 11. Referring briefly to FIG. 11, product web 36 is 
comprised of two side-by-side serial arrays of self-sealing valves 40. In 
use, the valves are separated from one another by severing along line 42 
(see the right hand end of FIG. 11) at a later time. If desired, the 
valves could be separated from one another by anvil cutters or the like at 
the outlet end 14 so as to be fed into a bulk storage bin or stacked in a 
magazine located in place of the rolls 24, 26. However, it is preferred 
that each serial array of valves be storm in continuous roll form. If 
desired, machine 10 could be readily altered to accommodate a single 
serial army of valves, or alternatively, three or more side-by-side arrays 
of valves, as may be desired. 
Referring to FIGS. 11 and 16, the valves 40 are formed by sealing films 32, 
34 together along sealing strips 46 so as to form a hollow channel 48 
between the sealing strips of each valve. In the preferred embodiment, the 
upper valve film 32 is substantially clear, without printed markings, 
while the lower valve film 34 has a plurality of regularly spaced segments 
50 of a heat resistant coating such as ink printed on the upper surface of 
valve film 34. As will be explained in greater detail herein, the product 
web 36 is slit along slit line 52 so that each valve subsequently formed 
will have a slit edge cutting through the heat resistant ink 50. As is 
commonly practiced in the balloon-making art, the slit ends of the 
self-sealing valve are typically located in the necks of toy balloons, the 
heat resistant ink preventing unintentional closure of the internal valve 
passageway when heat sealing dies are brought down on top of the valves, 
and their overlying balloon films. In the preferred embodiment illustrated 
in FIGS. 11 and 16, the numeral 56 indicates broadened portions of sealing 
lines 46. The sealing lines 46 and their broadened portions 56 are 
preferably formed by the same heat-sealing die 58, shown for example in 
FIG. 9. 
Referring to FIG. 9, heat-sealing die 58 has a bottom working surface 60 
comprising a series of recesses 62 located between end portions 64 and the 
pairs of main portions 66 of the heating die. Preferably, the heating die 
is formed of heat conducting material of metallic composition and is 
machined to form recesses 62, leaving the working portions 64, 66 to 
contact the balloon film, in heat-sealing engagement therewith. The 
heat-sealing die 58 may be heated by electrical resistance, ultrasonic 
excitation, or steam, for example. In practice, a Teflon sheet may be 
interposed between the heat-sealing die 58 and the balloon films, in a 
manner known in the art. In the preferred embodiment, three pairs of main 
portion 66 are provided, each forming a complete valve, while the two end 
portions 64 form only one of the two sealing lines 46, 56 needed for a 
valve. The footprint of the heat-sealing die 58 is indicated by the dotted 
rectangle 68 shown in FIG. 11. Referring to FIGS. 9 and 11, the left-hand 
end portion 64a forms sealing lines 46a in the product web 36. Thus, in 
the preferred embodiment, the sealing lines 46a are located at the tail 
end of each heat-sealing cycle indicated by the reference numeral 70 in 
FIG. 11. As can be seen in FIG. 11, the right- hand end portion 64b of 
heat-sealing die 58 results in sealing line 46b, which completes the 
incomplete valve portion at the trailing end of footprint 70b. 
As mentioned above, the heat-sealing die 58 forms a footprint 68 in the 
web, with each cycle of the heat-sealing die. The heat-sealing die is 
configured such that a complete valve product is formed with each cycle of 
operation. In the preferred embodiment, the valve product comprises a 
portion of valve films joined together so as to include six complete valve 
members and two partially complete valve members, all arranged in two 
laterally adjacent side-by-side arrays. The slitter separates the 
side-by-side serial arrays into separate serial arrays, as described above 
with reference to slit line 52. From the perspective of a manufacturer of 
valve products, the web may be regarded as comprising a serial succession 
of web portions, each portion corresponding to a footprint 70, with each 
footprint comprising a valve product. From the standpoint of a balloon 
manufacturer, formation of the valve product would be complete if the 
valves were formed in a single serial array. However, greater efficiencies 
are attainable in some instances where, as in the preferred embodiment, 
multiple serial arrays are formed with each cycle of the heat-sealing die. 
Balloon manufacturers sometimes prefer to sever individual valve members 
40 from the product web at the point of fabrication of a toy balloon. As 
mentioned above, if a balloon manufacturer wishes to receive individual 
valve members, a convention cutting station can be employed to cut the 
product web along line 42 shown in FIG. 11. As will be appreciated, the 
valve making apparatus is flexible so as to be readily adapted for 
different valve products, as may be desired. 
Referring again to FIG. 9, a punch mechanism generally indicated at 74 
includes four punch blades 76 which form punched slits 78 in the upper 
valve film 32. As can be seen at the right-hand end of FIG. 11, the 
punched slits 78 are divided by slit line 52 such that the punched slits 
appear at the inlet edge of the resulting valves 40. The punch 74 will be 
described in greater detail herein with reference to FIGS. 12 and 13. 
Also provided is a slitter mechanism 80 which includes a slitter blade 82 
which divides web 36 along the slit line 52, as shown in FIG. 11. The 
cooling head 84 has a lower working surface 86 and inlet and outlet fluid 
lines 88. Serpentine channels are formed in the interior of cooling head 
84 and coolant is circulated through the serpentine channels, thus cooling 
the working surface 86, transferring heat out of the cooling head by 
coolant flow in lines 88. As will be seen herein, the bottom working 
surface 86 of cooling head 84 is pressed against the recently heated 
footprints caused by pressing heat-sealing die 58 against the valve films. 
Despite the advantages of the heat-sealing die 58 (which incorporates both 
complete and partial valve formations in a single cycle of operation), it 
has been found that the heat-sealing die imparts a substantial heat 
loading to a localized area of the valve films, with each cycle of 
operation. Further, the valve films are chosen for optimum sell-sealing 
characteristics, or compatibility of bonding to conventional balloon films 
and for other design considerations unrelated to their ability to conduct 
heat away from a hot spot. It has been observed that the valve films 
sustain elevated temperatures after the heat-sealing die has been cycled 
which allows the valve films to pucker in these areas of local softening. 
Further, difficulties have been encountered when the valve films are slit 
immediately after heating. Accordingly, it has been advantageous to 
provide a cooling head 84 immediately downstream of the heat sealing die. 
The cooling head 84 presses the softened, heated areas maintaining and/or 
restoring their flatness, while heat is transferred to the fluid circuit 
in the cooling head. The cooling head, by cooling and flattening, 
conditions the valve films for subsequent slitting. 
As will be seen by comparing FIGS. 9 and 11, the footprint of the cooling 
head 84 does not match the footprints of the heat-sealing die 58. If 
desired, configuration of the cooling head can be changed and can be moved 
immediately adjacent the heat-sealing die, if desired. 
Referring to FIGS. 1-6, the workstation 30 includes the heat-sealing die 58 
and cooling head 84 (shown in greater detail in FIG. 6). The punch 74 is 
located upstream of workstation 30, at a punch station 90. Stiller 80 is 
located downstream of workstation 30, at a slitter station 92. 
Referring now to FIGS. 1-7, workstation 30 includes cross members 94 upon 
which actuators 96 are mounted. Actuators 96 preferably comprise 
double-ended air cylinders, with stops 98 provided at their upper end. 
Carriers 99 are attached to the bottom end of the actuators 96. As shown 
for example in FIG. 6, the carriers 99 are slidingly mounted on slide 
shafts 100, and work against coil springs 102. The coil springs provide a 
safety member, preventing the heat-sealing die 58 from falling down onto 
valve film if the operating signal to the actuator should be discontinued 
(e.g., loss of power to the facility). The electrical wires 104 energizing 
the heat-sealing die 58 could be opened by a switch in this eventuality, 
but the heat-sealing die 58 would nonetheless remain heated for some time. 
In the preferred embodiment, the actuator and support systems for the 
heat-sealing die 58 and for the cooling head 84 are substantially 
identical and thus a coil spring is provided to keep the cooling head 84 
above the valve film in a loss-of-power situation, although this is 
largely unnecessary. The identical mounting and actuation of the heating 
and cooling heads provides greater flexibility for machine 10, should 
reconfiguration be desired at some later time. Referring to FIGS. 4 and 5, 
position sensors, preferably of the optical type, are located atop 
actuators 96 to sense the position of the actuators, and hence of the 
heating and cooling heads attached thereto. These signals, as with other 
electrical connections, are routed to control cabinets 108, 110 shown in 
FIG. 2. Sealing control signals and cooling control signals are routed 
through the electrical connections to the respective actuators 96 for 
controlling the heat-sealing die 58 and cooling head 84, respectively. In 
the preferred embodiment, the cooling head and heat-sealing die are 
operated simultaneously, and accordingly, the same start signal, in 
effect, is sent to both actuators 96. However, it has been found 
advantageous to increase the dwell time of the cooling head, which allows 
the cooling head and its associated coolant circuit to have an 
inexpensive, conventional construction. In the preferred embodiment, 
ethylene glycol is circulated through the cooling head and an external 
radiator (not shown). Cryogenic and other more effective systems would 
reduce the cooling head dwell time, but would be difficult and costly to 
implement. 
Referring again to FIGS. 1-5 and 12-13, punch 74 is driven by an actuator 
110. Four blades 76 are mounted in a common head 112, with the head having 
a guide rod 114 sliding in a support ring 116 (as shown in FIG. 12). 
Control signals are sent to actuator 110 via inlet conduit 114. When 
actuator 110 receives a punch signal from control circuitry in control 
cabinet 110, output shaft 116, to which head 112 is attached, is lowered, 
with knife blades 76 piercing the valve film, as shown by the dotted 
rectangle 115 in FIG. 11. In the preferred embodiment, a shroud 120 guards 
the blade 76 against inadvertent contact, when the blades are in the 
raised position. 
Referring to FIGS. 1-6 and 15, the slitter mechanism 80 is mounted on a 
cross arm 122 suspended from the sides of frame 20. Slitter mechanism 80 
includes a slitter blade 82 which is plunged into the valve films at the 
initial setup of the machine, and which remains in place, to slit the 
resulting product web formed by successive cycles of the heat-sealing die. 
Referring to FIGS. 1-6, the supply rolls 16, 18 are mounted for rotation 
on support shafts 126, 128, respectively. Guide rollers 130, 132 and 
dancer arms 134, 136 are provided for the valve films 32, 34, 
respectively. The takeup rolls 24, 26 are preferably mounted on a common 
shaft 134 which is driven by a drive motor 320 (see FIG. 1) under control 
of a speed potentiometer 138. The speed potentiometer 138 is actuated by a 
follower arm 330 having a free end 332 and an opposed end pivotally 
mounted to frame 20. The product web 36 travels over guide roller 142 and 
dancer roller 144 before passing over the free end 141 of a rewind arm 
140. 
Turning now to FIG. 6, workstation 30 includes inlet nip rollers 150, 152 
and outlet nip rollers 154, 156 at the inlet and outlet ends of the 
workstation. The bottom nip rollers 152, 156 are driven by a timing belt 
158 having a tension adjustment mechanism 160. Timing belt 158 is driven 
by a motor 162 located in compartment 110 (see FIG. 2). As seen for 
example in FIG. 7, the lower nip roller 152 contains a series of O-rings 
164 (the same is true for nip roller 156). This provides enhanced 
frictional engagement of the film passing through the workstation. The 
upper nip roller 150 is preferably eccentrically mounted on shaft 156. As 
handle 168 is rotated, upper nip roller 150 is moved toward and slightly 
away from lower nip roller 152, thus providing a convenient pressure 
adjustment. When the desired pressure is obtained, via set screws, handle 
168 is automatically locked in position using conventional cam lock 
stopping means. The same arrangement is provided for the downstream nip 
roller 154. The upper nip rollers preferably function as idler rollers 
being driven by the lower nip rollers 153, 156. The upper nip rollers, as 
mentioned, are mounted on an eccentric roller bearing system and by 
turning the handle 168 in different directions, tension on the film 
passing through workstation 30 is either applied or removed, as desired. 
In the preferred embodiment, the nip rollers 152, 156 are driven through a 
slip clutch, and the timing belt and its associated drive are configured 
in a conventional manner such that the downstream nip roller 156 can be 
driven at a faster speed than the nip roller 152, if desired. Preferably, 
the amount of overspeed in the nip roller 156 is small, only enough to 
ensure the proper tension of film passing through workstation 30, but 
without causing stretching of the heat-softened film. 
With reference to FIG. 15, tension on the valve film in workstation 30 is 
controlled as described above, with operation of nip rollers at the 
upstream and downstream ends of the workstation. Speed on the output web 
is controlled by motor 320 (see FIG. 1) which receives speed control 
signals from speed potentiometer 138. Tension is controlled by rewind 
dancer arm, and also by rewind dancer weights 340 (see FIG. 1). Tension of 
the rolls 24, 26 are achieved by the rewind arm 140 and the amount of 
rewind dancer weights used. In effect, the nip rollers at workstation 30 
provide pulling power to the balloon films, which causes the films to be 
unwound from their supply rolls 16, 18. As will now be described, the 
shafts 126, 128 on which the supply rolls are mounted are controlled by 
respective braking systems generally indicated at 170. With reference to 
FIGS. 3, 10 and 14, operation of one break system 170, for the upper 
supply roll 16, will now be described. It should be borne in mind, 
however, that the braking system for the lower supply roll 18 is 
preferably identical. As mentioned above, valve film 32 travels over guide 
roller 130 and dancer roller 134. Dancer roller 134 is mounted on arm 172 
which in turn is pivotally mounted on shaft 174. As tension in valve film 
32 is increased, the dancer roller 134 is raised, thus rotating arm 172 in 
a clockwise direction. An adjusting rod 176 is coupled to the remote free 
end of arm 172 and is coupled to a disk brake lever or actuator 178, which 
extends from a floating caliper 180 of a conventional caliper disk brake. 
Brake pads operated by the floating caliper impart a braking pressure to 
disk 182 which in turn is mounted to shaft 126. As tension in film 32 is 
increased, and arm 172 is lowered in a clockwise position, this brake 
lever 178 is also operated in a clockwise direction to release braking 
pressure applied to disk 182 by floating caliper 180. As tension in film 
32 is decreased, an opposite sequence of actions occurs, resulting in 
increased pressure being applied to disk 182. As can be seen in FIG. 14, 
several braking adjustments are provided. For example, an adjustable 
weight 186 is provided for arm 172 to adjust the dancer arm tension. A 
coil spring 188 is provided to soften operation of the caliper disk brake, 
removing or softening impulsive input commands. As can be seen in FIG. 14, 
rod 176 is slidably coupled to arm 173 at coupling member 188. As a 
coupling member is moved toward shaft 174, a slower and softer response of 
the caliper disk brake is experienced. An opposite result is obtained when 
coupler member 188 is moved away from shaft 174. As shown in FIG. 14, 
spring 188 is adjusted by jam nuts 192 so as to be positioned at different 
points along guide rod 176. If the jam nuts 192 are raised, for example, 
the caliper disk brake requires a higher dancer arm position to initiate 
operation. 
The use of a heat-sealing die as described above, which forms a partial 
valve in addition to one or more complete valves, provides a number of 
advantages. For example, to form a complete valve, the die must be 
recessed, as described above, to bridge the spaced-apart lateral sealed 
edges of the valve. This bridging material can be omitted for end portions 
of the die where only a portion of a valve, i.e., a single lateral edge of 
the valve is formed. Other advantages obtain from the compact die 
configuration. In addition to lowered kinetic requirements for the die 
punching operation, vibrations in the die throughout its operating cycle, 
are also reduced. Because of the symmetric nature of the lateral edges of 
a valve, the partial valve seals, or end portions as described above, are 
mere images of one another and balancing of the heat-sealing die so as to 
reduce vibrations is relatively straightforward. In addition, the compact 
heat-sealing die radiates less heat to the web, while heat transfer in the 
compact die body is improved. 
Referring again to FIGS. 6 and 11, sensors 300, 302 monitor the web passing 
through workstation 30, and in particular, track the edges the edges of 
heat resist ink portions 50. The preferred sensors operate in an opposed 
mode of detection, with light passing through the emitter 302 to the 
receiver 300. Electrical conductors 304, 306 couple the emitter and 
receiver elements to control cabinet 110. Preferably, the trailing edge of 
the heat resist ink portions 50 triggers a control pulse which in turn 
controls the actuators 96 for the heat-sealing die 58 and cooling head 84. 
As can be seen in FIG. 6, it is generally preferred that the sensors 300, 
302 be located immediately adjacent the heat-sealing die. Because of the 
configuration of the heat-sealing die (i.e., its part-valve configuration) 
the sensors 300, 302 can be positioned over the portion of the web 
comprising the incomplete valve portion being formed by the heat-sealing 
die. Accordingly, close tolerances and increased accuracies can be 
obtained without requiring costly instrumentation. Because the sensors 
300, 302 are operated in an opposed mode of detection (with light passing 
from one sensor being received in the other sensor) small registration 
changes may be accomplished by moving only one of the sensors. Larger 
registration changes are accommodated by moving both sensors 300, 302. 
Turning again to FIG. 15, the overall web handling system will now be 
briefly reviewed. As mentioned, the web is comprised of upper and lower 
valve films 32, 34 drawn from supply rolls 16, 18. Two pairs of nip 
rollers are operated in synchronism by the timed driving arrangement 
described above with reference to FIG. 6. Preferably, the lower rollers 
152, 156 are powered so as to pull films 32, 34 from their supply rolls. A 
slip clutch is employed in the lower drive rolls so that the lower feed 
roll 156 turns slightly faster than the inlet feed roll 152 so as to 
assure a preselected tension in the web extending between the pairs of 
rollers. The films 32, 34 pass over respective dancer rollers 134, 136. 
These dancer rollers in turn are deflected by changes in film position, 
the deflection being transmitted to floating caliper disk brakes 170 to 
adjust the film and brake tension. 
Referring additionally to FIGS. 1, 9, 12 and 13, the upper film 32 is 
punched by punch block 74 to form crosswise slits 78 in the upper valve 
film. Since the slits 78 must be aligned with respect to the completed 
valves 40 (see, for example, FIG. 16), the actuator 110 for the punch is 
preferably driven by control signals generated from the aforementioned 
sensors 300, 302. As described above, the sealing and cooling heads are 
located immediately downstream of sensors 300, 302. In the preferred 
embodiment, laterally adjacent valves are formed with each operation of 
the heat-sealing die. With successive operations of the heat-sealing die, 
the nip rollers advance the web past workstation 30, so as to bring 
previously sealed portions of the web toward the outlet end of the 
machine, so as to position unsealed portions of the films 32, 34 
underneath the heat-sealing die. At this time, recently sealed (i.e., 
heated) portions of the web are positioned underneath the cooling head. 
With successive operations of the heading and cooling head and attendant 
advancement of the web, the product web (i.e., portions of the web in 
which valve elements are formed) passes underneath the slitter mechanism 
80 which divides the product web into two independent webs which are 
independently wound on respective rolls 24, 26. The slit webs pass 
underneath roller 141 to their respective takeup rolls. As the takeup 
rolls increase in size, the arm 143 is raised, and the changing position 
is sensed by potentiometer 138, with output signals from the potentiometer 
being coupled by conductors 310, 312 to drive motor 320, changing the 
speed at which the motor drives the takeup reels 24, 26. ON-OFF signals to 
the motor 320 are obtained by sensors which monitor the position of dancer 
roll 144. 
The drawings and the foregoing descriptions are not intended to represent 
the only forms of the invention in regard to the details of its 
construction and manner of operation. Changes in form and in the 
proportion of parts, as well as the substitution of equivalents, are 
contemplated as circumstances may suggest or render expedient; and 
although specific terms have been employed, they are intended in a generic 
and descriptive sense only and not for the purposes of limitation, the 
scope of the invention being delineated by the following claims.