[0001] This invention relates to a one-revolution stop mechanism for a dispenser and a dispensing
method for rolled web material of the flexible sheet type such as paper toweling.
The stop mechanism has a low operating force and is associated with the feed roller
in the dispenser to allow the feed roller to undergo one revolution and then be stopped
in dispensing an individual sheet of the rolled web material.
[0002] Dispensers for rolled flexible sheet material, such as paper toweling, are well-known
in the art and many of these dispensers include mechanisms for perforating or severing
a web of material to divide the web into individual sheets. Towel dispensers have
also been developed with various mechanisms or techniques to provide a waste-restricting
system, namely, the dispenser permits only a single individual sheet to be dispensed
to the intending user at one time with a delay being provided before the user can
gain access to a second individual sheet.
[0003] For sanitary reasons, towel dispensers in public washrooms should preferably be operable
by merely pulling down on an exposed portion of the towel web with no need to touch
parts of the dispenser such as cranks, buttons or levers commonly present in many
prior art types of towel dispensers, these actuators serving to activate the towel
dispenser in supplying the length of towel web or individual toweling sheets.
[0004] At the same time, for the sake of economy, the dispenser should eliminate unnecessary
waste of paper toweling while still not unduly restricting use of the toweling to
the intending user. Certain dispensers now on the market accomplish these objectives
by such devices as spring-operated one-revolution stop feeding mechanisms and vacuum
cup timers. Spring-operated devices have the disadvantage that in being cocked while
the towel is being withdrawn from the dispenser, a substantial drag is placed on the
web of paper toweling, often resulting in it being prematurely torn where it is held
by the wet fingers of the intending user. Prior art vacuum cup timers provide the
needed time delay between withdrawal of individual towel sheets to thus reduce waste
but have the disadvantage that the desired preset time intervals cannot be reliably
maintained especially at very short time interval settings.
[0005] In addition, in paper towel dispensers where the towel web is severed or perforated
internally, a device must be provided to prevent the premature separating of individual
towels from the following web as it uncoils from the supply roll of toweling. Strong,
thus, harsh, paper toweling is therefore required.
[0006] Figure 1 represents one example of a towel dispenser known in the prior art. The
dispenser 30 has a cabinet 31 adapted to be mounted at a convenient location for intending
users of the paper toweling supplied from the rolled web material carried within the
cabinet 31. A portion of the cabinet 31 is broken away to display a portion of the
one-revolution stop mechanism and other components mounted within the cabinet 31.
[0007] A roll 1 of flexible web material is mounted on a yoke 33, the yoke being pivoted
at 34 to the backplate of the dispenser cabinet 31. Yoke 33 has a pair of yoke arms
with cups 32 rotatably mounted at the outer ends of the yoke arms, these cups being
inserted at each core end into the central tubular core of the towel roll 1. With
this rather conventional mounting for roll 1, due to gravity the roll rests against
the backplate of cabinet 31 to provide a slight braking action and prevent overspinning
of the roll when the paper towel web is being removed.
[0008] The web W withdrawn from roll 1 is threaded counterclockwise around a pinchroller
3. The web then passes clockwise around the rearside of a feed roller 4 to pass counterclockwise
over an exit pinchroller 24. Pinchrollers 3 and 24 are pressed against the feed roller
4 by springs (not shown) with all rollers being supported by appropriate bearings
(not shown) in the sideplates of the dispenser cabinet 31. The web W then exits through
opening 26 in cabinet 31 to be accessible to intending users of the paper toweling
material coming from roll 1. Preferably a tab length T of the toweling web W of about
3 inches (7.6 cm) will extend outside the dispenser beyond opening 26 to be available
for grasping by the intending users of the web material. This preferred length T of
web material is automatically fed from the dispenser 30 in conjunction with the operation
of a one-revolution stop mechanism.
[0009] The feed roller 4 has an internal knife 40 which is mounted laterally offset from
the rotational axis of feed roller 4. Knife 40 is supported within the feed roller
to project through an opening (not shown) in the feed roller periphery to essentially
sever the web material when it passes over the feed roller surface as the feed roller
4 makes a single revolution. The web material is thus perforated to leave only, for
example, three uncut¼ inch (0.6 cm) long tabs connecting successive sheets in the
web. This transverse perforating of the web material in cabinet 31 defines individual
sheets which are of a length equal to the feed roller circumference so that the web
W is formed with a row of perforations between one sheet and the next succeeding sheet.
[0010] Details of the mounting and operating mechanism for the cutting knife 40 are not
shown but the construction may be of the sliding cutter construction disclosed in
U.S. Patent No. 4,712,461.
[0011] Feed roller 4 is rotatably mounted on shaft 32 which extends through an appropriate
bearing which is carried by the sidewall of cabinet 31. Shaft 32 extends outwardly
beyond the bearing and has a feed wheel 36 fixedly secured to it outer end. The feed
wheel 36 has a control tab 38 which cooperates with a stop lever 41 to constitute
the active components of the stop mechanism as described in allowed and commonly assigned
Application Serial No. 838,799 (now U.S. Patent No. ).
[0012] U.S. Patent No. Re 28,911 discloses the use of a conventional vacuum cup timer to
provide a time delay between withdrawal of individual towel sheets. The operation
of this type of timer will be explained with reference to Figures 2 and 3 which are
taken from Figure 10 of the Re. 28,911 patent.
[0013] Figure 2 is a side elevational view of the one-revolution stop mechanism in an unlatched
position as used in the dispenser disclosed in the Re. 28,911 patent. The mechanism
includes a feed wheel 240 which is drivenby the towel web being pulled from the dispenser.
The mechanism also includes a stop lever 230 which pivots about pivot pin 232. Stop
lever 230 has a cam follower 234 and a stop lug 236 which engage camming pin 238 formed
on feed wheel 240.
[0014] As shown in Figure 2, cam follower 234 is positioned in the rotational path of camming
pin 238. The rotation of feed wheel 240 causes camming pin 238 to engage the underside
of cam follower 234, raising cam follower 234 upwardly. Stop lever 230, thus, pivots
in a clockwise direction about pivot pin 232. As stop lever 230 pivots, vacuum cup
242 is draw into vacuum-gripping relationship with vacuum cup 244. As feed wheel
240 continues to rotate, camming pin 238 passes under and out of engagement with cam
follower 234 to arrive at the position shown in Figure 3. In this position, vacuum
cups 242 and 244 are in full vacuum-gripping relationship and stop lug 236 is in engagement
with camming pin 238. The vacuum-gripping force of vacuum cups 242 and 244 maintain
stop lever 230 in the position shown in Figure 3, thus preventing further rotation
of feed wheel 240 due to the engagement of camming pin 238 with stop lug 236. The
arrested motion of feed wheel 240 results in increased pulling force on the towel
which permits an individual sheet of paper toweling to be torn from the web along
preformed perforations.
[0015] Vacuum cups 242 and 244 remain in vacuum-gripping relationship for a predetermined
period of time which is regulated by needle valve 254. Needle valve 254 allows a controlled
flow of ambient air into the vacuum environment between vacuum cups 242 and 244 in
order to regulate the period of time during which the cups remain in vacuum-gripping
relationship. After the vacuum-gripping relationship is destroyed by the entry of
ambient air between vacuum cups 242 and 244, stop lever 230 is returned to its unlatched
position as shown in Figure 2 by spring 256 for the start of another cycle.
[0016] Though vacuum cup timers perform their intended function, they suffer from a number
of disadvantages. As mentioned above, the desired preset time delay interval cannot
be reliably maintained, especially at very short time interval settings. Another such
disadvantage is that a relatively large amount of compression force is required in
order to engage the vacuum cups in a vacuum-gripping relationship. Creation of such
a large force also creates a corresponding drag on the towel web, often resulting
in premature tearing of the towel. This particular disadvantage is addressed in the
Re. 28,911 patent by making one cup of a relatively hard resilient material and the
other of a relatively soft resilient material. The use of a soft resilient material
also provides a better cushion for absorption of forces generated by the abrupt arresting
of feed wheel movement, thus minimizing wear of the stop mechanism components.
[0017] Though the use of resilient material for one of the vacuum cups presents a solution
to the high compression force problem, other problems are created. For example, manufacturing
cost are increased due to the need to fabricate cups from two different materials.
There are obvious economies to be realized if both cups are of the same design and
material. In addition, reducing the hardness of the vacuum cups also reduces the vacuum-gripping
force between the cups.
SUMMARY OF THE INVENTION
[0018] It is the overall objective of the present invention to provide a towel dispenser
which can be operated at a low user pull force.
[0019] It is a specific objective of the present invention to provide a one-revolution stop
mechanism for a dispenser which requires substantially less force to cycle than such
mechanisms known in the prior art.
[0020] It is a further specific objective of the present invention to provide a one-revolution
stop mechanism which permits a towel dispenser to be used with a wide variety of
soft-ply paper towels.
[0021] It is another specific objective of the present invention to provide a one-stop
revolution mechanism which is efficient and reliable in operation.
[0022] It is a still further objective of the present invention to provide a towel dispenser
wherein individual towels reliably separate from the web outside of the dispenser.
[0023] The rolled web dispenser of this invention basically overcomes the above-mentioned
disadvantages of prior art dispensers by eliminating the use of feed-out springs
altogether and provides a great improvement over the conventional use of vacuum cup
timers. The present invention provides a fully reliable momentary stop and time delay
which makes possible the use of very soft and weak paper toweling, with the dispenser
being operated solely by pulling on the paper web of toweling while still providing
the desired waste restricting system.
[0024] The dispenser for rolled web flexible material of this invention overcomes the disadvantages
discussed above with reference to prior art proposals by providing a stop mechanism
for the feed roller which has a substantial advantage over conventional stop lever
designs. Thus a relatively small force by the user in pulling a towel from the dispenser
is translated in a correspondingly larger force for setting the vacuum cups into vacuum-gripping
engagement. As a result, operation of the dispenser is made much easier. The stop
lever in accordance with Applicant's invention has a long actuating arm which pivots
about a pivot point. The long actuating arm creates a substantial mechanical advantage
for setting the vacuum cups in vacuum-gripping engagement. The mechanism advantage
afforded by the stop lever of Applicant's invention greatly enhances the low pull
force requirement and smooth operation of the dispenser. The pneumatic and elastic
characteristics of the stop mechanism which incorporates Applicant's stop lever serves
as an efficient way of absorbing the energy generated when the dispensing mechanism
is cycled and abruptly stopped.
[0025] In addition, the problem with prior art dispensers having conventional spring biased
exit pinch rollers is overcome by Applicants dispenser. In Applicant's dispenser,
the exit pinch roller is allowed to float in a slot. The slot is in angular relationship
with the feed roller such that the web is drawn into biting relationship with the
pinch roller when the web is pulled. This arrangement assures that the towel will
separate outside the dispenser when pulled.
[0026] The above objectives and features of the invention will become apparent upon consideration
of the detailed description of a preferred embodiment of the invention in connection
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027]
Figure 1 is a side elevational view, with portions in section, of a rolled web dispenser.
Figure 2 is an elevational view of the stop mechanism and associated elements used
in a prior art dispenser, wherein the stop mechanism is in an unlatched position.
Figure 3 is an elevational view of the stop mechanism and associated elements used
in a prior art dispenser, wherein the stop mechanism is in a latched position.
Figure 4 is a side elevational view of a rolled web dispenser in accordance with Applicant's
invention displaying the stop mechanism associated with the feed roller and feed wheel.
Figure 5 is a side view of a stop lever and vacuum cup timer in accordance with Applicant's
invention.
Figure 6 is a side elevational view of a vacuum cup timer in accordance with Applicant's
invention.
Figure 7 is a side elevational view showing the operation of the exit pin roller in
a prior art dispenser.
Figure 8 is a side elevational view showing the operation of an exit pin roller in
accordance with Applicant's invention.
Figure 9 is a side elevational view of another embodiment of the vacuum cup timer
of Applicant's invention.
Figure 10 is a front side elevational view of another embodiment of the camming lug
which cooperates with the stop lever of Applicant's invention.
Figure 11 is a cross-sectional view taken along line 11-11 in Figure 10.
Figure 12 is a rear side elevation view of the camming lug shown in Figure 10.
Figure 13 is a cross-sectional view taken along line 13-13 in Figure 12.
Figure 14 is an enlarged elevational view of the center portion of Figure 10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] Figure 4 illustrates one embodiment of the one-revolution stop mechanism of Applicant's
invention. Web W withdrawn from roll 1 is threaded counterclockwise around a pinchroller
3 through a nip 2. The web then passes clockwise around the rearside of feed roller
4 to pass counterclockwise over exit pinchroller 6 through a nip 5. The web then exits
through opening 27 in cabinet 31 to be accessible to intending users of the paper
toweling material coming from roll 1. Preferably a tab length 7 of the toweling web
W of about 3 inches (7,6 cm) will extend outside the dispenser beyond opening 27 to
be available for grasping by the intending users of the web material. This preferred
length 7 of web material is automatically fed from the dispenser 30 in conjunction
with the operation of the stop mechanism in accordance with Applicant's invention.
[0029] The feed roller 4 has an internal knife as known in the art which is mounted laterally
offset from the rotational axis of feed roller 4. The knife is supported within the
feed roller to project through an opening (not shown) in the feed roller periphery
to essentially sever the web material when it passes over the feed roller surface
as the feed roller makes a single revolution. The web material is thus perforated
to leave only three uncut ¼ inch (0.6 cm) long tabs connecting successive sheets in
the web. This transverse perforating of the web material in cabinet 31 defines individual
sheets which are of a length equal to the feed roller circumference so that the web
W is formed with a row of perforations between one sheet and the next succeeding sheet.
[0030] Feed roller 4 is rotatably mounted by a shaft which extends through a bearing which
is carried by the sidewall of cabinet 31 at pivot point 19. The shaft extends outwardly
beyond the bearing and has a feed wheel 8 fixedly secured to its outer end. The shaft
and feed wheel 8 are driven by the towel web being pulled from the dispenser. The
feed wheel 8 has a camming lug 9 which cooperates with a stop lever 15.
[0031] Stop lever 15 is pivotally mounted at point 11 on one of the side plates of dispenser
cabinet 31 and is provided with a recipient arm 12, a long actuating arm 18 and a
short actuating arm 17. Vacuum cup 13 is attached to the end of arm 12 which cooperates
with vacuum cup 14 as shall be discussed below.
[0032] As web W is being pulled from the dispenser by a user, actuating lug 9 rotates with
feed wheel 8 and engages surface 10 of stop lever 15 as shown in Figure 5, thus causing
a movement of stop lever 15 about pivot point 11. As stop lever 15 pivots, vacuum
cup 13 is bought into vacuum engagement with vacuum cup 14 to expel air trapped between
the vacuum cups. This is the compression stroke of stop lever 15. The air expelled
from between vacuum cups 13 and 14 causes a vacuum to be created between the cups.
The vacuum causes stop lever 15 to be held in a latched position as shown in Figure
5. During this initial period, feed wheel 8 continues to rotate until lug 9 engages
surface 16 of short arm 17. When this occurs, feed roller 4 and the freedom of movement
of the web material are abruptly stopped. Thus, the pull applied by the intending
user on the web separates the web along the row of perforations for the user to receive
an individual sheet.
[0033] Thus in summary, when web W is pulled through the dispenser, feed roller 4 is caused
to rotate which in turn causes feed wheel 8 to rotate in a corresponding manner. After
feed wheel 8 has rotated a predetermined distance, lug 9 engages and slides across
surface 10 of arm 18, thereby causing arm 18 to pivot upwardly about pivot point 11.
Accordingly arm 12 causes vacuum cup 13 to engage vacuum cup 14. The relatively high
mechanical advantage of long arm 18 pivoting stop lever 15 about point 11 causes cup
13 to firmly engage fixed cup 14, thus expelling air trapped in cavity 20 (See Figure
6) formed by the vacuum cups. A seal 21 is formed by the lips of the mating vacuum
cups, thus holding arm 12 down by the pneumatic pressure created by the vacuum. Arm
17 is therefore held in a latched upward position so that lug 9 engages surface 16
to interrupt the rotation of feed wheel 8.
[0034] The low force required to create the relatively high mechanical advantage provided
by stop lever 15 for setting vacuum cups 13 and 14 is abruptly reversed by the high
pneumatic force holding arm 12 in position 21 as shown in Figure 6 and the relatively
low mechanical leverage force exerted by arm 17 to resist the rotational force of
lug 9 as lug 9 engages surface 16 of arm 17. When vacuum cups 13 and 14 are compressed,
they perform a most critical function.
[0035] Both the pneumatic and elastic characteristics of Applicant's stop mechanism serves
to absorb the energy generated when the mechanism is cycled and abruptly stopped.
As feed wheel 8 rotates and lug 9 strikes surface 16 of short arm 17, stop lever 15
tries to rotate around pivot 11 and separate vacuum cups 13 and 14. However, due
to the position stop lever 15 has now taken, the forward rotation of the mechanism
is arrested, energy is dissipated and the towel web separates along perforations.
[0036] Applicant has found that the relationship between dimensions A and B and radius C
of stop lever 15, as illustrated in Figure 5, can be optimized to achieve smooth and
effortless operation of the stop mechanism. The relatively long length of arm 18 provides
a significant mechanical advantage for sitting vacuum cups 13 and 14 in vacuum-gripping
relation.
[0037] It has been found that dimension A should be at least one-half that of dimension
B. Such a length permits a relatively small amount of camming force from lug 9 to
be translated into a relatively large force at the end of arm 15 for setting vacuum
cups 13 and 14 in vacuum gripping relationship.
[0038] The mechanical advantage manifest by the construction of Applicant's stop lever is
made evident by the greatly reduced force required of the user to pull a single towel
from the dispenser. In addition, the smooth camming action of lug 9 along surface
10 results in the smooth operation of the stop mechanism which is apparent to the
user.
[0039] As shown in Figure 5, radius C is chosen such that surface 10 is in line with pivot
point 11 while lug 9 is in engagement with surface 10 as illustrated in Figure 5.
This orientation of surface 10 with pivot point 11 creates an easy progression of
force between surface 10 and lug 9 as lug 9 passes through its toggle point between
surface 10, lug 9 and pivot point 19.
[0040] After a predetermined delay, it is necessary to provide a venting device to induce
air back into the vacuum created when vacuum cups 13 and 14 were compressed so that
chamber 20 can be reformed. The venting device can be on either the moving cup 13
or the fixed cup 14. Needle valve 25 shown in Figure 6 serves this purpose. An orifice
22 is provided in vacuum cup 14 which cooperates with stem 23. Air can be metered
into chamber 20 by moving stem 23 relative to orifice 22 and allowing the air to
bleed past threads 24.
[0041] Figure 9 illustrates another embodiment of the vacuum cup timer of Applicants invention.
In this embodiment, flat plate 29 replaces vacuum cup 14.
[0042] Figures 10-14 illustrate another embodiment of lug 9. Lug 9a extends from the center
portion of feed wheel 8 and has a shank portion 9b. Shank portion 9b provides additional
shock absorption characteristics and has been found by Applicant to lend considerable
reliability to the stop mechanism.
[0043] In paper towel dispensers where the towel web is severed or perforated internally,
a device must be provided to prevent the premature separating of individual towels
from the following web as it uncoils from the supply roll of toweling. In prior art
dispensers, spring biased exit pinch rollers were used as shown in Figure 7. To be
effective, a high degree of force is required to hold this type of pinch roller in
contact with the feed roller, requiring greater force to cycle the mechanism. Strong,
thus, harsh, paper toweling is therefore required.
[0044] If a lower spring force is used to lower the energy requirements for cycling the
mechanism in order to dispense a soft plush towel, the lower pinch roller would move
out of contact with the feed roller when the towel web is pulled out of the dispenser
shown in Figure 7. In this case the towel will separate at point 25, or further back
in the mechanism, thus making the dispenser appear to be empty.
[0045] Applicant's dispenser overcomes this problem by the use of a lower pinch roller 6
which is mounted in a slot 26 as shown in Figure 8. Slot 26 is in angular relationship
E, as illustrated in Figure 8, with the feed roller so as to move away from nip 5
when the mechanism is cycled and into a biting relationship when the web is pulled.
This assures that the towel will separate outside the dispenser past point 5. In the
above configuration, shaft 27 is allowed to float so that the portion of web 7 exerting
the most pressure on roller 6 will be held the firmest at point 5.
[0046] It should be obvious from the above-discussed apparatus embodiment that numerous
other variations and modifications of the apparatus of this invention are possible,
and such will readily occur to those skilled in the art. Accordingly the scope of
this invention is not to be limited to the embodiment disclosed, but is to include
any such embodiments as may be encompassed within the scope of the claims appended
thereto.
1. A dispenser (30) for rolled web material (W), said dispenser comprising:
a dispenser cabinet (31) having means (32,33,34) in said cabinet (31) for mounting
a roll (1) of web material (W);
a feed roller (4) rotatably mounted on a shaft (32) in said cabinet to guide said
web from the roll (1) to the exterior of said cabinet, so that said web may be grasped
by a user and pulled out of said dispenser;
camming pin means (38,238,9) rotatable with said feed roller (4) and spaced radially
from the feed roller axis for providing a camming action;
a cutter mechanism (40) associated with said feed roller (4) to transversely perforate
said web as it passes over said feed roller; and
a stop mechanism for stopping the operation of said feed roller (4) to arrest the
movement of said web (W) for a predetermined period of time after a predetermined
length of said web (W) has been withdrawn from said dispenser (30);
characterized in that said stop mechanism comprises lever means (15) mounted to pivot
in a plane normal to the axis of said feed roller (4) for activating said stop mechanism,
said lever means having a first engagement arm (18), a second engagement arm (17)
and an actuating arm (12), a first end of each of said arms (18,17,12) terminating
at a pivot point (11) of said lever means (15), said first engagement arm (18) being
adapted to engage said camming pin means (9) to raise said first engagement arm (18)
to a high level and said actuating arm (12) to a low level as said feed roller (4)
rotates, said second engagement arm (17) being adapted to engage said camming pin
means (9) after said first engagement arm (17) has been raised, said second engagement
arm (17) holding said camming pin (9) and preventing said feed roller from rotating
for a predetermined period of time.
2. A dispenser according to claim 1, wherein a feed wheel (8) is fixedly secured to
said shaft means (32) and said camming pin means (9) is carried by said feed wheel
(8).
3. A dispenser according to claim 1, 2, wherein said cutter mechanism comprises a
cutting blade (40) mounted within said feed roller (4).
4. A dispenser according to claim 1, 2 or 3, wherein said first engagement arm (18)
has a cam follower surface (10) which engages said camming pin means (9), said surface
(10) being aligned with the pivot point (11) of said lever means.
5. A dispenser according to any one of the preceding claims, wherein said camming
pin means (9) and said first engagement arm (18) cooperate to provide a mechanical
advantage with respect to said actuating arm (12).
6. A dispenser according to any one of the preceding claims, further comprising timer
means (13,14,25) activated by said actuating arm (12), to produce said predetermined
period of time.
7. A dispenser according to claim 6, wherein said timer means comprises vacuum cup
means (13,28) drawn into vacuum-gripping relation by said actuating arm (12) with
another vacuum cup means (14) or plate means (29), said vacuum gripping relation holding
said first engagement arm (18) in the raised position for said predetermined period.
8. A dispenser according to claim 6 or 7, wherein said predetermined period is regulated
by valve means (28) for destroying said vacuum gripping relation.
9. A dispenser according to claim 2, wherein said camming pin means (9) comprises
a cam portion (9a) and a shank portion (9b), said shank portion (9b) extending along
a side of said feed wheel (8) to a center portion of said feed wheel (8), said shank
portion (9b) being attached to said feed wheel (8) at said center portion.
10. A dispenser according to claim 2 or 9, wherein said camming pin means (9) or said
cam portion (9a) thereof is located adjacent the peripheral side edge of said feed
wheel (8).
11. A dispenser according to any one of the preceding claims, further comprise exit
roller means (6) adjacent said feed roller (4) for pinching said web material (W)
between said feed roller (4) and said exit roller (6) when said web material (W) is
pulled from said dispenser (30).
12. A dispenser according to claim 11, wherein said exit roller (6) is mounted on
a shaft (27) which is retained in an opening (26) which provides said shaft freedom
of movement within said opening (26).
13. A dispenser according to claim 12, wherein said opening is a slot (26).
14. A dispenser according to claim 13, where said slot (26) is in an angular relation
(E) with said feed roller (4).