Note: Descriptions are shown in the official language in which they were submitted.
CA 02211233 1997-07-23
WO 96/261~4 PCI/US95/02308
ROLL SUPPORT HUB BRAKING MECHANISM
Technical Field
The present invention relates generally to roll support hubs which are rotatablysupported on a dispensing or applying app~ldlus and which can be used for
supporting a variety of roll products, such as adhesive tape rolls. More specifically,
10 the present invention is directed to a manner of controlling the rotation of the hub
about its support and to provide a braking action against the rotation of the roll.
Background
Roll support hubs are known to be used on automatic, semi-automatic, and manual
15 apparatuses from which roll products are to be dispensed or applied. Moreover, it
is known to provide a friction braking mech~nicm which acts against the rotation of
such a roll support hub so that the tension of the material dispensed can be
controlled and to prevent over-rotation of the roll when demand is ceased.
20 Adhesive tape dispensers and applicators are one type of device which typically
requires a roll support hub. Many types of tape dispensers and applicators are
known depending on the area of use, for example: for industrial packaging lines.store p~ck~gin~ and wrapping, or in an office environment. Typically, the purpose
of these type tape dispensers is to facilitate the use of the tape from such a
25 dispenser, and to do so in accordance with the specific application.
Manual tape dispensers are typically used in small packaging departments and, aswell known, typically consist of a roll support hub which rotates on a support axle
or bolt which is projected from a support base that may be equipped with a handle.
30 Other conventior.al features include guiding mechanisms and cutting mech~nicrn~.
Such roll support hubs are known to include a braking system, normally comprising
a controlled friction braking system, with its primary purpose to regulate the
rotation of the tape roll. The braking system, of such known tape dispensers.
CA 02211233 1997-07-23
W O96/26144 ' PCTrUS95/02308
includes on one side of the roll support hub a friction surface in a perpendicular
plane to the axis of rotation which is fixed with the roll support hub and rotates with
the roll support hub around the support axle and by a sliding pressure disc that is
axially slidably mounted to the support axle and on which operates an adjustable5 spring. The braking action is determined by the amount of pressure of the spring
applied to the pressure disc which is frictionally engaged with the friction surface of
the roll support hub.
A typical set-up of a roll support hub that is provided as part of a manual tape10 dispenser is shown in Figure 1. A roll support hub 1 is illustrated and which is
rotatable about a support axle 2 which is in turn fixed with a tape dispenser support
3, again which is typically provided with a handle and a cutting means. Such
support axles 2 are typically secured to the support frame 3 to be non-rotational,
such as by a rivet shown at 4. The hub I includes a bearing 5 which is rotational on
15 the support axle ~. On the side of the roll support hub I away from the support
frame 3, a shoulder 6 is provided extending from the bearing 5 and which provides
a friction surface that is in a general plane perpendicular to the axis of the support
axle 2.
20 At the other end of the support axle 2 from the support frame 3, a non-circular
portion 7 of the support axle 2 extends above the plane of the friction surface of the
shoulder 6. By this, a pressure disc 8 having a corresponding opening is supported
to be axially slideable on the non-circular portion 7, but rotationally fixed with the
support axle 2. A knob 9 is adjustably mounted to the support axle 2, such as by a
25 bolt 10 so that the distance between the lower surface of the knob 9 and theupper
surface of the pressure disc 8 can be adjustably defined. Between the lower surface
of the knob 9 and the pressure disc 8, a compression spring 11 is provided whichprovides a biasing force against the pressure disc 8 toward the friction surface of the
roll support hub 1.
,
CA 02211233 1997-07-23
WO 96/26144 PCI/US95/02308
Between the pressure disc 8 and the friction surface of the shoulder 6, a friction disc
12 is also provided. The friction disc 12 is typically rotatable about the non-circular
portion 7 of the support axle 2. As can be seen, the rotatable roll support hub 1
rotates about the fixed support axle 2. As the roll support hub 1 rotates, its
5 shoulder portion 6 experiences relative movement between itself and the non-
rotational pressure disc 8. The compression spring 11 provides the force against the
pressure disc 8 which increases the friction between the surfaces of the pressure disc
8, the friction disc 12, and the friction surface of the shoulder 6. By adjustment of
the knob 9, the force generated by the colllpression spring 11 can be controlled so
10 as to increase or decrease the friction between the aforementioned elements. By
this, a controlled friction can be applied to the roll support hub 1 to regulate the
rotation of the roll hub support l and thus the dispensing of material from the roll.
This set-up, as mentioned above, is at present almost universally used; however,15 certain deficiencies exist. The ring-shaped friction disc, and the friction surfaces on
the pressure disc 8 and the shoulder 6 are considerably reduced so that, to obtain a
sufficient braking force, it is necess~ry to use a particularly strong compression
spring 11 that is adjusted to provide a-heavy load. A first specific problem is that
the braking action under such a heavy load can be difficult to control, which can
20 frequently result in dispensing with too much or not enough braking action.
Additionally, it is a problem that the edge of the bearing S of the roll support hub l
that is adjacent the support frame 3 is pushed against the support frame 3 with a
force that is so strong that it causes a rapid wearing of the base portion of the
bearings. Referring again to Figure 1, in order to deal with this latter problem, it is
25 known to provide a sleeve 13 at the base portion of the bearing 5, although this
clearly adds to the complexity of the manufac~uring and increases costs of
production. Normally, the roll support hub I is made of a plastic material, such as
polypropylene, which is relatively ineffective against wear. The sleeve 13 can be
made of a material that is more effective against wear, for example Delrin~, which
30 is extremely effective against wear and tear, but is substantially more expensive.
CA 02211233 1997-07-23
~' . '..
PCT~US95/02308 ~innes~ta Mining& ~,;,~(~I.. i~gC~
51425PCTlA
-I- 12Feb~a~ 1997
DE-C-454270 describes a braking device for rolls or drums which includes a conically
shaped pressure element which locates in a similarly shaped recess in a hollow shaft. The
hollow shaft is supported on the pressure elements at each end thereof so that with
5 decreasing weight of the roll or drum the frictional braking force-,also reduces.
Summary of the Present Invention j~ -
It is a primary purpose of the present invention to provide an improved braking system to
a rotatable roll support hub for a roll product of web mat~ial that is capable of providing
a smoother and progressive braking action which uses a less powerful compression spring.
o This can be achieved by the apparatus according to claim 1.
The above described advantages are achieved in the manner noted above for providing a
smoother progressive braking action which is applicable to any roll support hub on which
a controlled braking force is desirable. Such may include manual tape dispensers, as
described above, or any other roll support hub for any roll of web material which is
5 associated with an automatic, semi-automatic, or manual dispensing or applying apparatus.
Further characteristics and advantages of the braking system of the present invention will
be evident from the detailed description which follows, which is directed to a preferred
embodiment, which is given and illustrated by the attached drawing.
20 Brief description of the Drawinj~
Figure 1 is an asymmetrical axial cross-sectional view with the right side of the figure as
viewed in Figure 1 taken at a 90~ plane and the left side at a plane less than 90~ of a Prior
Art roll support hub and braking system.
Q:\WEB\5 1425CLA.WD6
AP~ENDE~ ~El
CA 02211233 1997-07-23
wo s6n6l44 P~-lIU~7~ 2308
Figure 2 is a similar axial cross-sectional view as taken in Figure 1 but showing a
roll support hub and a braking system in accordance with a ~l~fell~d embodiment
of the present invention.
-
5 Detailed Description of the Preferred EmbodimentA ~rere-led embodiment in accordance with the present invention is illustrated in
Figure 2. Basically, a roll support hub 20 is provided that has a number of similar
components and functionality as that illustrated in the Figure I Prior Art
illustration, except that the components having the corresponding friction surfaces
l0 are provided in the manner of frustoconical surfaces. The roll support hub 20 is
rotatably supported by a support axle 22 which is in turn preferably non-rotationally
fixed with a support frame 24 by any- conventional means such as shown by a rivet
26. The support frame 24 can comprise a side frame element of any conventional
manual applicator or dispenser from which web material provided in roll form, such
15 as adhesive tape, can be dispensed. Likewise, the support frame 24 can be a
portion of a support for a semi-automatic or automatic machine from which any roll
material may be dispensed. One specific manual dispenser to which the present
invention is specifically applicable is the manual adhesive tape dispenser
commercially available from Minnesota Mining and Manufacturing Company of St.
20 Paul, Minnesota as ScotchTM Model H-181 hand dispenser. An example of an
automatic taping m~ ine to which the subject roll support hub may be applied is
the 3MTH Model 800-AF case sealer available from Minnesota Mining and
Manufacturing Company of St. Paul, Minnesota. In any case, the roll support hub
of the present invention could be merely rotationally mounted to a fixed axle
25 connected with the existing support structure.
The roll support hub 20 includes a bearing 28 which rides on the outer surface of
the support axle 22 during rotation of the roll support hub 20. At the end of the
bearing 28, away from the support frame 24, a frustoconical portion 30 of the roll
30 support hub 20 is provided having a friction surface 32 which faces toward the
CA 02211233 1997-07-23
W O96/26144 PCTrUS~SJ'~230
support axle 22 by at least some degree. The angle of the friction surface 32 from a
perpen-~icul~r plane to the axis of rotation can be any angle less than 90~ but greater
than 0~, with the underst~n-lin~ that the angle affects the amount of surface area, as
described below. As illustrated, the roll support hub 20 integrally includes the5 bearing 28 and frustoconical portion 30; however~ it is understood that the roll
support hub 20 could be made of multiple components. The roll support hub 20 is
also preferably dimensioned such that at its outer diameter it is sized to fit within
the core of a roll of web material which is to be dispensed from the particular
dispenser. Preferably, the roll support hub 20 is sized to frictionally engage the
10 inner surface of the core of the roll of web material to be dispensed so that the roll
material rotates with the roll support hub 20 by a frictional engagement.
At the end of the support axle 22, away from the support frame 24, a non-circular
portion 34 is provided onto which a pressure disc 36 is disposed. The pres~ule disc
15 36 preferably includes an opening which is similarly shaped to the non-circular
portion 34 so that the pressure disc 36 can slide along the length of the non-circular
portion 34 but cannot rotate relative to the support axle 22. The pressure disc 36
also preferably includes a frustoconical portion 38 having a similar slope to the
slope of the frustoconical portion 30 of the roll support hub 20. The frustoconical
20 portion 38 also preferably provides a friction surface 40 on its surface facing the
friction surface 32 of the frustoconical portion 30 of the roll support 20. At the
wide end of the pressure disc 36, a rim flange 42 is also preferably provided
extending away from the support axle 22 and at the upper edge of the friction
surface 40. The rim flange 42 may not be provided at all, or may be provided
25 lower along the friction surface 40 as will be more fully understood with the description of the operation below.
A knob 44 is adjustably connected with the support axle 22 by a threaded bolt 46 so
that the space between the lower surface of the knob 44 and the upper surface of the
CA 02211233 1997-07-23
W O96/26144 PCTrUS95/02308
pressure disc 36 can be varied by rotating the knob 44 which in turn moves the
threaded bolt 46 to extend or within the bolt 46 to the ~Uy~Jul l axle 22.
. A co"l~ression spring 48 is positioned between the knob 44 and the pressure disc 36
5 and is provided for exerting a biasing force against the pressure disc 36 for urging it
toward the frustoconical portion 30 of the roll support hub 20. Preferably, the
co",pression spring 48 is positioned within a receiving groove 50 on the lower side
of the knob 44 on the one end and within a receiving groove 52 provided on the
upper surface of the pressure disc 36 on the other end. It is a significant advantage
10 of the present invention that the compression spring 48 can have a significantly
lower spring force than that of prior art devices, because less force is required in
order to achieve similar braking forces, as will be more fully described in the
operation below.
15 A frustoconical friction disc 54 is also preferably provided between the friction
surface 40 of the pressure disc 36 and the friction surface 32 of the frustoconical
portion 30 of the roll support hub 20, although not nec~os~ry. The friction disc 54
provides an inner friction surface 56 and an outer friction surface 58 which engage
with friction surfaces 40 and 32, respectively. The friction disc 54 may be freely
20 rotatable about the support axle 22, although it may be fixed with one of thepressure disc 36 or the roll support hub 20. However, if it is desirable to
specifically generate the friction braking action between the friction disc 54 and the
frustoconical 30 of the roll su~po, l hub 20, for example, it would be desirable to
prevent the friction disc 54 from rotation about the support axle 22. To do this, the
25 friction disc 54 may be fixed with the pressure disc 36 by any conventional means
or may just be rotationally fixed such as providing corresponding ribs and grooves
on the friction surfaces 40 and 56 which engage with one another to prevent the
rotation of the friction disc 54 when the pressure disc 36 is urged against the friction
disc 54. It is also noted that with the provision of the rim flange 42, the
30 frustoconical friction disc 54 should be appropriately dimensioned to fit within the
CA 02211233 1997-07-23
WO96/26144 F~l/u~7sl~23o8
space between the ~es~u~e disc 36 and the frustoconical portion 30 of the roll
support hub 20, so that an ~plop,ia~e frictional force can be generated. The rimflange 42 additionally provides a force to urge the frustoconical friction disc 54
toward the frustoconical portion 30 of the roll support hub 20.
The result of the above-described construction is the provision o~ frictional surface
areas that are significantly greater than in the case of the prior art roll support hub
illustrated in Figure 1 and described above in the Background section of this
application. In order to change the frictional surface area, the angle of the conical
surfaces can be varied. With this construction, the frictional surface area of the
embodiment shown in Figure 2 can be as much as doubled the frictional surface
area of that illustrated in Figure 1. Moreover, the pressure created by the
compression spring 48 on the pre~ e disc 36 tr~n.~l~t~s both to pressure applied by
the friction disc 54 in the direction perpendicular to the frustoconical portion 30 of
the roll support hub 20 and in the direction of the axis of the support axle 22, which
may be mainly caused by the rim flange 42 acting to force the friction disc 54 to the
frustoconical portion 30 of the roll support hub 20.
In operation, a user would simply load a roll of web material, such as adhesive
tape, onto the roll support hub 20 so that the roll of material rotates with the roll
support hub 20. As the roll material is dem~nded or dispensed, the roll support hub
20 rotates about the support axle 22 on its bearing 28. At all times, the
compression spring 48 urges the pressure disc 36 to move along the non-circular
portion 34 in the axial direction toward the support frame 24. The result of this
urging is the additional urging of the frustoconical portion 38 of the p-~ssule disc 36
into the frustoconical friction disc 54 and likewise into the frustoconical portion 30
of the roll support hub 20. During rotation of the roll support hub 20, the pressure
disc 36 does not rotate and the friction disc 54 may or may not rotate. If the
friction disc 54 is fixed with the pressure disc 36, all the friction is generated
between the outer surface 58 of the friction disc 54 and the friction surface 32 of the
CA 02211233 1997-07-23
W O96/26144 PCTAUS95~ 308
frustoconical portion 30 of the roll support hub 20. If the friction disc 54 is freely
rotatable, some friction would also be provided between the inner friction surface
56 and the friction surface 40 of the frustoconical portion 38 of the pressure disc 36.
Again, because of the increase in frictional surface areas, the con~ ession spring 48
5 can be significantly less strong than the spring force associated with prior art
mechanisms. Since the spring force is weaker, the braking action can be more
effectively controlled and can be progressive over a greater range and smoother
throughout the range. In order to adjust the braking force, a user would merely
rotate the knob 44 to change the distance between its lower surface and the pressure
10 disc 36 and thus change the spring force. Another important advantage of the use
of a weaker spring, is the reduction of force generated between the base of bearing
28 and the support frame 24. With a weaker spring, less force is generated between
these surfaces during rotation, and it is not nPcess,.ry to provide a wear-resistant
sleeve, such as has been done with prior art supports. The entire bearing 28 can15 thus be made integral with the roll support hub 20 and of the same material.
