U.S. patent application number 10/337464 was filed with the patent office on 2004-07-08 for treadmill belt.
This patent application is currently assigned to Siegling America, LLC. Invention is credited to Canipe, Sandra Vause, Leighton, Jay Philip.
Application Number | 20040132586 10/337464 |
Document ID | / |
Family ID | 32681245 |
Filed Date | 2004-07-08 |
United States Patent
Application |
20040132586 |
Kind Code |
A1 |
Leighton, Jay Philip ; et
al. |
July 8, 2004 |
Treadmill belt
Abstract
An endless treadmill includes a bottom-ply fabric that at least
partially forms a bottom surface of the belt that is for sliding
across a treadmill deck. The bottom-ply fabric has warp yarns that
at least partially form the bottom surface of the belt, with a
large number of these warp yarns, and preferably all of these warp
yarns, being less than about 1000 denier, or more preferably about
500 denier or smaller. In addition, the warp yarns that at least
partially form the bottom surface of the belt are twisted about 2.5
complete turns per inch, or less. A solid lubricant composition is
preferably impregnated in the bottom-ply fabric. The solid
lubricant composition includes a wax mixture and it optionally
further includes a lower viscosity lubricant, such as silicone. The
wax mixture may include a vegetable wax and a mineral wax, such as
a mixture of paraffin wax and carnauba wax.
Inventors: |
Leighton, Jay Philip;
(Charlotte, NC) ; Canipe, Sandra Vause;
(Harrisburg, NC) |
Correspondence
Address: |
ALSTON & BIRD LLP
BANK OF AMERICA PLAZA
101 SOUTH TRYON STREET, SUITE 4000
CHARLOTTE
NC
28280-4000
US
|
Assignee: |
Siegling America, LLC
|
Family ID: |
32681245 |
Appl. No.: |
10/337464 |
Filed: |
January 7, 2003 |
Current U.S.
Class: |
482/54 |
Current CPC
Class: |
A63B 22/0285 20130101;
A63B 22/0207 20151001; B29D 29/00 20130101; A63B 22/02
20130101 |
Class at
Publication: |
482/054 |
International
Class: |
A63B 022/02 |
Claims
That which is claimed:
1. An endless treadmill belt for extending in a longitudinal
direction around and traveling relative to a deck, the belt
comprising: a fabric that at least partially forms a bottom surface
of the belt and is for sliding across the deck, with the fabric
including a plurality of weft yarns extending in a lateral
direction that is substantially perpendicular to the longitudinal
direction, and a plurality of warp yarns extending in the
longitudinal direction for slidingly engaging the deck, wherein
each warp yarn of the plurality of warp yarns is less than about
1000 denier, and an at least substantially solid lubricant is
impregnated in the fabric and at least partially forming the bottom
surface of the belt.
2. An endless treadmill belt according to claim 1, wherein the
lubricant includes carnauba wax.
3. An endless treadmill belt according to claim 2, wherein the
lubricant is a lubricant composition and the carnauba wax is
present within the lubricant composition in amounts ranging from
about 30 weight percent to about 70 weight percent.
4. An endless treadmill belt according to claim 1, wherein the
lubricant includes a wax mixture.
5. An endless treadmill belt according to claim 4, wherein the wax
mixture includes at least one vegetable wax and at least one
mineral wax.
6. An endless treadmill belt according to claim 5, wherein the
vegetable wax is selected from the group consisting of carnauba
wax, candelilla wax, bayberry wax and wax derived from sugar
cane.
7. An endless treadmill belt according to claim 5, wherein the
vegetable wax is present within the lubricant composition in an
amount of about 50 weight percent.
8. An endless treadmill belt according to claim 5, wherein the
vegetable wax is present within the lubricant composition in an
amount of about 36 weight percent.
9. An endless treadmill belt according to claim 5, wherein the
mineral wax is selected from the group consisting of earth waxes
and petroleum waxes.
10. An endless treadmill belt according to claim 5, wherein the
mineral wax is paraffin wax.
11. An endless treadmill belt according to claim 5, wherein the
mineral wax is present within the lubricant composition in amounts
ranging from about 30 weight percent to about 70 weight
percent.
12. An endless treadmill belt according to claim 5, wherein the
mineral wax is present within the lubricant composition in an
amount of about 50 weight percent.
13. An endless treadmill belt according to claim 5, wherein the
mineral wax is present within the lubricant composition in an
amount of about 35 weight percent.
14. An endless treadmill belt according to claim 1, wherein the
lubricant is a lubricant composition which includes at least one
higher viscosity lubricant and at least one lower viscosity
lubricant, with the higher viscosity lubricant having a higher
viscosity than the lower viscosity lubricant, and the lubricant
composition being a substantially uniformly dispersed mixture.
15. An endless treadmill belt according to claim 14, wherein the
lower viscosity lubricant is selected from the group of silicones,
mineral oils, polyglycols and mixtures thereof.
16. An endless treadmill belt according to claim 14, wherein the
lower viscosity lubricant includes a silicone lubricant.
17. An endless treadmill belt according to claim 14, wherein the
lower viscosity lubricant is present in the lubricant composition
in an amount ranging from about 20 weight percent to about 40
weight percent.
18. An endless treadmill belt according to claim 1, wherein each
warp yarn of the plurality of warp yarns is about 500 denier or
smaller.
19. An endless treadmill belt according to claim 1, wherein each
warp yarn of the plurality of warp yarns is twisted, with each warp
yarn of the plurality of warp yarns being twisted less than about
2.5 complete turns per inch.
20. An endless treadmill belt according to claim 19, wherein each
warp yarn of the plurality of warp yarns is about 500 denier or
smaller.
21. An endless treadmill belt according to claim 1, wherein each
warp yarn of the plurality of warp yarns is twisted within a range
of about 1.5 to about 2.0 complete turns per inch.
22. An endless treadmill belt according to claim 21, wherein each
warp yarn of the plurality of warp yarns is about 500 denier or
smaller.
23. An endless treadmill belt according to claim 1, wherein the
belt is in combination with and extends around the deck, and the
combination further comprises: a frame to which the deck is
mounted; a pulley rotatably mounted to the frame and around which
the belt extends, with the pulley carrying the belt; and a motor
mounted to the frame and operative for causing the belt to travel
relative to the deck, so that the bottom surface of the belt slides
across an upper surface of the deck.
24. An endless treadmill belt for extending in a longitudinal
direction around and traveling relative to a deck, the belt
comprising: a fabric that at least partially forms a bottom surface
of the belt and is for sliding across the deck, with the fabric
including a plurality of weft yarns extending in a lateral
direction that is substantially perpendicular to the longitudinal
direction, and a plurality of warp yarns extending in the
longitudinal direction for slidingly engaging the deck, wherein
each warp yarn of the plurality of warp yarns is twisted, with each
warp yarn of the plurality of warp yarns being twisted less than
about 2.5 complete turns per inch, and an at least substantially
solid lubricant is impregnated in the fabric and at least partially
forming the bottom surface of the belt.
25. An endless treadmill belt according to claim 24, wherein the
lubricant is a lubricant composition having at least one vegetable
wax and at least one mineral wax.
26. An endless treadmill belt according to claim 25, wherein the
vegetable wax includes carnuaba wax.
27. An endless treadmill belt according to claim 25, wherein the
vegetable wax is present within the lubricant composition in
amounts ranging from about 30 weight percent to about 70 weight
percent.
28. An endless treadmill belt according to claim 25, wherein the
mineral wax is a petroleum wax selected from the group consisting
of paraffin wax and microcrystalline wax.
29. An endless treadmill belt according to claim 25, wherein the
mineral wax includes paraffin wax.
30. An endless treadmill belt according to claim 25, wherein the
mineral wax is present within the lubricant composition in amounts
ranging from about 30 to 70 weight percent.
31. An endless treadmill belt according to claim 24, wherein the
lubricant is a lubricant composition which includes at least one
higher viscosity lubricant and at least one lower viscosity
lubricant, with the higher viscosity lubricant having a higher
viscosity than the lower viscosity lubricant.
32. An endless treadmill belt according to claim 31 wherein the
lower viscosity lubricant includes silicone lubricant.
33. An endless treadmill belt according to claim 31, wherein the
lower viscosity lubricant is present in the lubricant composition
in an amount ranging from about 20 weight percent to about 40
weight percent.
34. An endless treadmill belt according to claim 24, wherein each
warp yarn of the plurality of warp yarns is twisted within a range
of about 1.5 to about 2.0 complete turns per inch.
35. An endless treadmill belt for extending in a longitudinal
direction around and traveling relative to a deck, the belt
comprising: a fabric that at least partially forms a bottom surface
of the belt and is for sliding across the deck, and an at least
substantially solid lubricant composition impregnated in the fabric
and at least partially forming the bottom surface of the belt,
wherein the lubricant composition is a substantially uniformly
dispersed mixture including wax and no more than about 40 weight
percent of a silicone lubricant.
36. An endless treadmill belt according to claim 35, wherein the
fabric includes a plurality of weft yarns extending in a lateral
direction that is substantially perpendicular to the longitudinal
direction, and a plurality of warp yarns extending in the
longitudinal direction for slidingly engaging the deck, and wherein
each warp yarn of the plurality of warp yarns is less than about
1000 denier.
37. An endless treadmill belt according to claim 35, wherein the
fabric includes a plurality of weft yarns extending in a lateral
direction that is substantially perpendicular to the longitudinal
direction, and a plurality of warp yarns extending in the
longitudinal direction for slidingly engaging the deck, and wherein
each warp yarn of the plurality of warp yarns is twisted, with each
warp yarn of the plurality of warp yarns being twisted less than
about 2.5 complete turns per inch.
38. An endless treadmill belt for extending in a longitudinal
direction around and traveling relative to a deck, the belt
comprising: a fabric that at least partially forms a bottom surface
of the belt and is for sliding across the deck; and an at least
substantially solid lubricant composition impregnated in the fabric
and at least partially forming the bottom surface of the belt,
wherein the lubricant composition includes at least one vegetable
wax, at least one mineral wax, and at least one silicone
lubricant.
39. An endless treadmill belt according to claim 38 wherein the
vegetable wax includes carnauba wax.
40. An endless treadmill belt according to claim 38, wherein the
mineral wax includes paraffin wax.
41. An endless treadmill belt according to claim 38, wherein the
lubricant composition mixture includes vegetable wax in an amount
ranging from about 30 weight percent to about 40 weight percent,
and mineral wax in an amount ranging from about 30 weight percent
to about 40 weight percent.
42. An endless treadmill belt according to claim 38, wherein the
silicone lubricant makes up no more than about 40 weight percent of
the lubricant composition mixture.
43. An endless treadmill belt according to claim 38, wherein the
belt is in combination with and extends around the deck, and the
combination further comprises: a frame to which the deck is
mounted; a pulley rotatably mounted to the frame and around which
the belt extends, with the pulley carrying the belt; and a motor
mounted to the frame and operative for causing the belt to travel
relative to the deck, so that the bottom surface of the belt slides
across an upper surface of the deck.
44. A method of manufacturing, comprising: lubricating a belt
material by applying a liquid lubricant composition which includes
at least one silicone lubricant to the belt material; drying the
liquid lubricant composition to form an at least substantially
solid lubricant composition; then cutting a section from the belt
material so that the section includes opposite ends and opposite
edges extending between the opposite ends, with the lubricating
being carried out so that at least substantially all of a broad
surface of the section is impregnated with the at least
substantially solid lubricant composition, with the broad surface
being substantially contiguous with and spanning between the ends
and edges; and splicing the ends together so that the section is
endless and extends around a space, and the first broad surface
faces the space.
45. A method according to claim 44, wherein lubricating the belt
material includes lubricating a fabric of the belt material, such
that the broad surface includes the fabric, and wherein the method
further includes encircling a deck with the endless section and
driving the endless section with a motor while the endless section
is encircling the deck, so that the lubricated fabric slides across
the deck.
Description
BACKGROUND OF THE INVENTION
[0001] The present inventions relate to belts and belt lubricants,
and more particularly to lubricated, endless belts for
treadmills.
[0002] Treadmills used for exercise are well known and very
popular. A prior art exercise treadmill typically includes an
endless belt that is driven by a motor so that the bottom surface
of an upper run of the belt slides across an upper surface of a
stationary deck. In use, a person using the treadmill engages the
top surface of the upper run of the belt at a position above the
deck, which contributes to friction between the bottom surface of
the upper run and the upper surface of the deck. Over the years,
efforts have been made to reduce this friction, in an effort to
reduce: the power required to drive the belt, friction-induced
heating, and friction-induced noise. Reducing the friction can
enhance the operation and life of the belt. It is known to reduce
the friction between treadmill belts and decks through the use of
lubrication, and there are several known lubricants and associated
methods.
[0003] It is prior art to apply a lubricant, such as a lubricant
consisting of polypropylene wax, a polyurethane binder and solvent,
to rolls of belt material before forming endless belts (e.g.,
"light duty" belts, which are discussed below in this Background
section) from the belt material. Then, the solvent is driven off by
heating, so that the resultant lubricant is impregnated in the belt
material and is substantially in solid form at room temperature.
Thereafter, sections are cut from the belt material and joined
(e.g., spliced) end-to-end to form the endless belts that are used
as treadmill belts. Although the foregoing method of lubricating is
very efficient in some regards, it can only be used with limited
types of lubricants, because some lubricants will interfere with
the splicing.
[0004] It is prior art to apply a liquid silicone lubricant to the
bottom surface of an endless treadmill belt. When using a liquid
silicone lubricant, the lubricant is typically individually sprayed
or rolled onto individual treadmill belts after the treadmill belts
have been formed/made endless. According to one prior art method,
an endless belt is placed on a lubricating fixture having three
rollers that the belt extends around such that the "bottom" (i.e.,
"inner") surface of the belt engages the pulleys and the "top"
(i.e., "outer") surface of the belt faces away from the pulleys.
One of pulleys is driven and an applicator applies the silicone
lubricant to the bottom surface as the belt travels relative to the
applicator.
[0005] The liquid silicone provides adequate lubrication, but since
it remains in liquid form, it has a tendency to migrate to the top
surface of the belt, to any packaging materials used when shipping
the belt, or to other locations where lubrication is not desired.
Additionally, if too much silicone liquid is applied, belt tracking
problems can result, meaning that the belt can become misaligned
around the pulleys of the treadmill. If too little silicone liquid
is used, belts are inadequately lubricated, which can
disadvantageously increase the amount of power required to drive
the belt, as well as the heat and noise generated by the belt
sliding across the deck, which can negatively impact the life and
operation of the belt. Finally, lubricating endless belts
individually is slow and labor intensive compared with coating
rolls of belting prior to forming endless belts therefrom.
Typically, liquid silicone cannot be efficiently applied to rolls
of belting before making numerous endless belts therefrom because
the liquid silicone will interfere with bonding/adhesion that is
necessary for satisfactorily splicing.
[0006] It is also prior art to apply wax to the upper surface of
the deck of a treadmill. The wax can provide adequate lubrication
only if a sufficient quantity is used. If too much is used, wax
clings to treadmill rollers resulting in excessive noise and
tracking difficulties. After a period of use, wax is typically lost
from the deck such that some form of relubrication is necessary. As
one example, U.S. Pat. No. 3,659,845 discloses a treadmill with a
stationary support surface over which the upper run of a belt
travels, and the upper surface of the support surface is formed
from canvas that is impregnated with a wax, such as carnauba
wax.
[0007] Whether or not a lubricant is used, the underlying
construction of a treadmill belt can also affect the amount of
friction resulting from the treadmill belt sliding across the deck.
For example, a prior art "light-duty" treadmill belt, which is
particularly well suited for use in homes, will now be described.
The light-duty belt has all polyester top and bottom plies that are
joined by an adhesive (e.g., polyurethane or PVC) positioned
between the top and bottom plies. The top ply is a plain weave of
1000 denier multifilament polyester yarns, and the bottom ply,
which includes the bottom surface that slides across the deck, is a
plain weave, with both weft and warp yarns being spun polyester
yarns formed from staple fibers. This "light-duty" belt is formed
by cutting a section from a roll of belt material after the belt
material has been lubricated as described above, so that the bottom
surface of the bottom ply of the belt is impregnated with a
lubricant mixture of polypropylene wax and polyurethane binder. The
endless belt is formed by splicing the opposite ends of the cut
section together. The splice is a "Z" splice, meaning that opposite
ends of the section are cut in a zigzag pattern and then meshed
together, with a PVC strip hot-pressed at the meshed area, over the
top surface of the top ply.
[0008] As an additional example, a prior art "heavy-duty" treadmill
belt, which is particularly well suited for use in spas, will now
be described. The heavy-duty belt has all polyester top and bottom
plies that are joined by an adhesive (e.g., polyurethane or PVC)
positioned between the top and bottom plies. The top ply is a plain
weave of 1000 denier multifilament polyester yarns. In the bottom
ply of these belts, the weft yarns, which extend across the belt,
are monofilament, and warp yarns, which extend in the longitudinal
direction (i.e., the direction of belt travel), are 1000 denier
multifilament polyester yarns (i.e., "continuous" filament yarns).
Plain weaves as well as twill weaves (e.g., 3/1) are used for the
bottom ply. In the twill bottom plies, the long, floating portions
of the warp yarns contact the deck that the belt slides across,
with the belt traveling in the longitudinal direction in which the
warp yarns extend. Likewise, the belt travels in the longitudinal
direction in which the warp yarns extend for the plain weave. In
these belts, the warp yarns are twisted about 130 turns/meter. For
this "heavy-duty" belt, it is formed by cutting a section from a
roll of belt material and forming a continuous belt via splicing
the opposite ends of the section together. The splice is formed by
peeling back plies at the opposite ends and then overlapping and
sealing together those overlapped portions. This type of belt is
typically run on a waxed deck or otherwise used in a treadmill with
an automatic lubricating system that sprays lubricant onto the belt
during use of the treadmill.
[0009] Although prior treadmill belts operate reasonably well,
there is always a desire for new treadmill belts that provide an
improved balance of properties.
BRIEF SUMMARY OF THE INVENTION
[0010] One aspect of the present invention is the provision of belt
materials and/or belts that provide an improved balance of
properties, and methods of making and using the belts and/or belt
materials. A more specific aspect of the present invention is the
provision of endless treadmill belts that are each for extending
around and sliding across a treadmill deck, and that provide an
improved balance of properties. Preferably the improved balance of
properties results from fabric(s) of the belts and/or lubricant(s)
impregnated in the belts. One aspect of the present invention is
the fabric(s) which are preferably, but not limited to being,
bottom-plies of the belts, and another aspect of the present
invention is the lubricant(s) which are preferably, but not limited
to being, impregnated in the bottom-plies of the belts.
[0011] In accordance with one aspect of the present invention, an
endless treadmill belt is preferably multi-ply and includes a
bottom-ply fabric that at least partially forms a bottom surface of
the belt, and the bottom surface is for sliding across a treadmill
deck. In accordance with one example of this aspect, the bottom-ply
fabric has warp yarns that at least partially form the bottom
surface of the belt, with a large number of these warp yarns, and
preferably all of these warp yarns, being less than about 1000
denier, or more preferably about 500 denier or smaller. In
accordance with this same or another example of this aspect, the
warp yarns that at least partially form the bottom surface of the
belt are twisted about 2.5 complete turns per inch, or less.
[0012] In accordance with one aspect of the present invention, a
lubricant coating composition is preferably impregnated into the
bottom surfaces of the endless treadmill belts that are for sliding
across the decks of treadmills. In accordance with one aspect of
the present invention, the lubricant includes a wax mixture and it
optionally further includes a lower viscosity lubricant, such as a
silicone lubricant. The wax mixture is preferably a mixture of at
least one vegetable wax and at least one mineral wax. In accordance
with the exemplary embodiment of the present invention, the
vegetable wax is carnauba wax, and the mineral wax is paraffin wax.
Preferably the lubricant is a substantially uniformly dispersed
mixture.
[0013] In accordance with one example of the present invention, the
lubricant coating composition impregnated in an endless treadmill
belt is at least substantially solid. Such solid lubricant coating
compositions are preferably formed from liquid lubricant
compositions that include solvents. In some of the embodiments of
the present invention, the solvents are substantially entirely
volatilized after the liquid lubricant is applied to the belt
material from which endless belts are formed, and after
volatilization of the solvents, the belt material is cut into
lengths from which endless belts are formed.
[0014] Each of the endless treadmill belts of the present invention
is preferably used in combination with a deck, so that the belt
extends around and slides across the deck. The combination
preferably further includes a frame to which the deck is mounted,
pulleys rotatably mounted to the frame and around which the belt
extends, and a motor mounted to the frame and operative for causing
the belt to travel relative to the deck, so that the bottom surface
of the belt slides across an upper surface of the deck. The
improved balance of properties according to one aspect of the
present invention pertains to there being an acceptably low
coefficient of friction at the interface between the bottom surface
of the belt and the upper surface of the deck.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Having thus described the invention in general terms,
reference will now be made to the accompanying drawings, which are
not necessarily drawn to scale, and wherein:
[0016] FIG. 1 is a schematic, perspective view of portions of a
prior art treadmill in accordance with a comparative embodiment,
and FIG. 1 is illustrative of features of an exemplary embodiment
of the present invention;
[0017] FIG. 2 is a schematic, elevational, partial view of a
longitudinally extending edge of an upper run of the prior art belt
of FIG. 1, in accordance with the comparative embodiment;
[0018] FIG. 3 diagrammatically illustrates prior art methods and
apparatus for forming endless belts from a roll of belt material,
in accordance with the comparative embodiment, and FIG. 3 is
illustrative of features of the exemplary embodiment of the present
invention;
[0019] FIG. 4 is a schematic, elevational, partial view of a
longitudinally extending edge of an upper run of a treadmill belt,
in accordance with the exemplary embodiment of the present
invention; and
[0020] FIG. 5 is a chart illustrating the performance of the belt
of the exemplary embodiment of the present invention as compared to
a conventional, comparable belt.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The present invention now will be described more fully
hereinafter with reference to the accompanying drawings, in which
some, but not all embodiments of the invention are shown. Indeed,
the invention may be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein;
rather, these embodiments are provided so that this disclosure will
satisfy applicable legal requirements. Like numbers refer to like
elements throughout.
[0022] A lubricated treadmill belt of an exemplary embodiment of
the present invention has an improved balance of properties.
Nonetheless, some features of the exemplary embodiment of the
present invention are not novel per se. Accordingly, in the
following, a comparative embodiment, which is prior art to the
present invention, is first described with reference to FIGS. 1-3,
followed by a description of the exemplary embodiment of the
present invention. FIGS. 1-3 are diagrammatically/generally
illustrative of some features of the exemplary embodiment of the
present invention.
COMPARATIVE EMBODIMENT
[0023] FIG. 1 is a schematic, perspective view of portions of a
prior art treadmill 20 in accordance with a comparative embodiment.
The treadmill 20 includes an endless belt 21 that is carried by a
frame and driven by a motor 22. The belt 21 is endless by virtue of
opposite ends of the belt being joined together at a joint 23,
which is preferably in the form of a splice. That is, the joint 23
is diagrammatically illustrative of a splice. The belt 21 is
substantially uniform along its length, except for at the joint
23.
[0024] The frame includes a pair of longitudinally extending frame
members 24 that are spaced apart from one another in a lateral
direction. The belt 21 is partially cut away in FIG. 1, to more
fully show a stationary deck 26 that is mounted to and extends
laterally between medial portions of the frame members 24. Front
and rear pulleys 28 are rotatably mounted to the frame members 24
and extend laterally between the frame members. The pulley 28 at
the front of the frame is driven, via a drive belt 30, by the motor
22, which is mounted to the frame. The belt 21 extends around the
pulleys 28 and the deck 26 so that the bottom surface of the upper
run of the belt engages the pulleys and deck, and the top surface
of the upper run faces away from the pulleys and deck. In use, the
feet of a person using the treadmill engage the top surface of the
belt 21 at a position above the deck 26, which contributes to the
friction resulting from the bottom surface of the belt sliding
across the upper surface of the deck. In some cases, the upper
surface of the deck 26 is unwaxed, or the upper surface of the deck
26 can have wax 32 thereon, in an effort to reduce the
friction.
[0025] FIG. 2 is a schematic, elevational, partial view of a
longitudinally extending edge of the upper run the prior art belt
21, in accordance with the comparative embodiment. The belt 21
includes top and bottom plies 34, 36 that are each woven polyester,
and the top and bottom plies are joined to one another by an
intermediate ply/adhesive 38 therebetween. In use, the feet of a
person using the treadmill 20 engage a top surface 40 of the belt
21 at a position above the deck 26. The top surface 40 is defined
by a PVC coating 41 that is adhered to and covers the top ply 34.
The bottom ply 36 includes the bottom surface 42 of the belt that
slides across the upper surface of the deck 26 (FIG. 1). The belt
21 includes a lubricant coating composition 43 that is impregnated
in the bottom ply 36 and is proximate the bottom surface 42. In
FIG. 2, the lubricant coating composition 43 is schematically
illustrated by stippling (i.e., dots and flicks) in the bottom ply
36.
[0026] FIG. 3 diagrammatically illustrates prior art methods and
apparatus for forming endless belts 21 from a roll 44 of belt
material 46, in accordance with the comparative embodiment. The
belt material 46 is unwound from a roll 44 by one or more transport
mechanisms 48 arranged along the travel path of the belt material.
The belt material 46 is transported through a coater 50, such that
the surface of the belt material that will eventually contact the
upper surface of the deck 26 (FIG. 1) is facing upward. That is,
the bottom ply of the belt material 46 is facing up. Any type of
suitable coater known in the art of wide web or textile coating may
be used. Exemplary coaters include knife coaters, roll coaters, and
the like. In the coater 56, the belt material is preferably
transported through a nip defined between an upper knife edge and a
lower roller. A liquid coating composition is applied to (e.g.,
poured onto, or the like) the bottom ply of belt material 46 at a
position just upstream from the nip, so that the liquid coating
composition is impregnated into the bottom ply of the belt material
as it passes through the nip.
[0027] Thereafter, the belt material 46 with the impregnated liquid
coating composition is transported through a drying oven 52 using a
tenter frame or the like. The solvent component of the liquid
coating composition is volatilized in the drying oven 52, resulting
in an at least substantially solid lubricant coating 43 being
impregnated in the bottom ply of the belt material. The dwell time
for each incremental portion of the belt material within the drying
oven 52 is about 1 to 5 minutes, or more specifically about 2
minutes, and the temperature within the oven is about 80.degree. to
160.degree. C., or more specifically about 100.degree. C.
Thereafter, the belt material is transported through a cooling
mechanism 54, where the coated belt material is cooled, such as by
nipping the coated belt material between chilled rollers. The
coated belt material 56 is then formed into a roll 57. Thereafter,
and in some cases at a different facility, the coated belt material
56 is unwound from the roll 57 by one or more transport mechanisms
58 positioned along the travel path of the coated belt material 56.
At a cutting mechanism 60, sections of belt material 62 are cut
from the coated belt material 56. At a splicing mechanism 64, each
of the sections of belt material 62 is joined end-to-end to form an
endless belt 21.
Exemplary Embodiment
[0028] An exemplary embodiment of the present invention is like the
comparative embodiment described above, except for variations noted
and variations that will be apparent to those of ordinary skill in
the art. Accordingly, elements of the exemplary embodiment that at
least generally correspond to elements of the comparative
embodiment are respectively identified by the same reference
numerals, increased by a hundred.
[0029] FIG. 4 is a schematic, elevational, partial view of a
longitudinally extending edge of the upper run of the belt 121 of
the exemplary embodiment of the present invention. The belt 121
includes top and bottom plies 134, 136 that are joined by an
intermediate ply/adhesive 138 therebetween. The top surface 140 of
the belt 121 is preferably substantially planar and is preferably
defined by a coating 141, which is preferably PVC, that is adhered
to and covers the top ply 134. The coating 141 is preferably
embossed with an amorphous, orange-peel-like pattern. Embossing a
treadmill coating with an amorphous, orange-peel-like pattern is
not novel per se.
[0030] The bottom ply 136 includes a bottom surface 142 that slides
across the upper surface of the deck 26 (FIG. 1). Between the
pulleys 28 (FIG. 1), the bottom surface 142 is preferably
substantially planar, except for the texture of the fabric of the
bottom ply 136 and any discontinuity in the region of the splice 23
(FIG. 1). The exemplary embodiment of the present invention is not
limited to the type of deck 26 or type of treadmill 20 illustrated
and described with reference to FIG. 1, because the belt 121 of the
exemplary embodiment of the present invention operates
advantageously with a wide range of different types of decks and
treadmills, and with a wide variety of other types of conveyor
structures.
[0031] In accordance with the exemplary embodiment of the present
invention, the belt 121 is preferably formed by splicing together
opposite ends of a section of belt material. Preferably, the splice
(e.g., see splice 23 in FIG. 1) extends at an oblique angle
relative to the longitudinally extending edges of the endless belt
121, and the belt 121 is preferably substantially uniform along its
length, except for in the region of the splice. The splice is
preferably an "overlap splice," meaning that it is formed by
peeling back plies at the opposite ends of the section of belt
material and then overlapping and sealing the peeled plies.
[0032] As noted above, the belt 121 preferably includes three main
layers: a top ply 134, an intermediate ply/adhesive 138 and a
bottom ply 136. In accordance with the exemplary embodiment
illustrated in FIG. 4, the top ply 134 is preferably a plainly
woven fabric. The top ply 134 may be formed of any woven fabric
exhibiting sufficient durability and flexibility, such as a woven
fabric formed from polyester yarns, particularly multifilament
polyester yarns having a denier of about 1000. As used herein, the
term "yarn" refers to any continuous strand of textile fibers,
filaments or material in a form suitable for knitting, weaving, or
otherwise intertwining to form a textile fabric. In accordance with
the exemplary embodiment of the present invention, it is preferred
for all of the fabrics of the belt 121 to be constructed solely of
man-made filaments/fibers, although natural fibers may be used in
alternative embodiments.
[0033] The intermediate ply/adhesive 138 is preferably formed from
an elastomeric material. In accordance with the exemplary
embodiment of the present invention, the intermediate ply/adhesive
138 is formed from a cured elastomeric material, such as a cured
polyurethane.
[0034] The bottom ply 136 may be formed from any fabric providing
sufficient strength, durability and frictional properties to the
resulting belt construction. In accordance with the exemplary
embodiment of the present invention, the fabric of the bottom ply
136 preferably includes an effective amount of relatively fine
and/or low twist warp yarns. As used herein, the term "warp yarn"
refers to those yarns within a given layer which extend in the
longitudinal direction, i.e., along the length of the belt 121.
Correspondingly, as used herein, the term "weft yarns" refers to
those yarns within a given layer that extend in the transverse
direction, i.e. across the belt 121. Although not wishing to be
bound by theory, theoretically the incorporation of relatively fine
and/or low twist warp yarn into the bottom ply 136 decreases the
coefficient of friction between the bottom surface 142 of the belt
121 and the deck 26 (FIG. 1).
[0035] Accordingly, an effective amount of the warp yarns within
the bottom ply 136 preferably have a relatively fine denier, such
as a denier of less than about 1000, and, more preferably, a denier
of about 500 or smaller. As an additional example, an effective
amount of the warp yarns within the bottom ply 136 can have a
denier ranging from about 150 to 500. In accordance with the
exemplary embodiment of the present invention, preferably 100% of
the warp yarns of the fabric of the bottom ply 136 are the
relatively fine denier yarn.
[0036] The warp yarns of the bottom ply 136 preferably additionally
or alternatively possess low twist, such as a twist of less than
about 2.5 complete turns per inch, and most preferably twist
ranging from about 1.5 to 2.0 complete turns per inch. Regarding
the warp yarns of the bottom ply 136, a twist of about 2.0 complete
turns per inch may be most preferred for facilitating weaving,
whereas a twist of about 1.5 complete turns per inch may be most
preferred for reducing the friction generated between the bottom
ply 136 and the deck 26 (FIG. 1) while the treadmill is in
operation.
[0037] In accordance with the exemplary embodiment of the present
invention, the bottom ply 136 warp yarns preferably are formed from
polyethylene terephthalate, they are about 500 denier or smaller,
and each is twisted about 1.5 to 2.0 complete turns per inch; the
bottom ply 136 weft yarns are preferably formed from monofilament
fiber, and the monofilament weft yarns each preferably have a
diameter of about 0.25 mm; the fabric of the bottom ply 136 is
preferably a plain weave; and the bottom ply 136 fabric has
45.times.50 yarns per inch (i.e., 45 warp ends per inch and 50 weft
ends per inch). One exemplary commercially available fabric for use
in the bottom ply 136 is Style No. 930388, produced by Milliken
& Company of Spartanburg, S.C.
[0038] In accordance with an alternative embodiment of the present
invention, the fabric of the bottom ply 136 is a twill weave,
preferably a 2/1 twill weave. In embodiments including 2/1 twill
weaves, the warp yarn preferably passes under two weft yarns for
every weft yarn it passes over, so that the long, floating portions
of the warp yarns contact the upper surface of the deck 26 (FIG.
1).
[0039] As mentioned above, the relatively fine size and/or the low
twist of the warp yarns in the bottom ply 136 are believed to
reduce friction between the bottom surface 142 of the belt 121 and
the deck 26 (FIG. 1). In accordance with the exemplary embodiment
of the present invention, the coefficient of friction between the
bottom surface 142 of the belt 121 and the deck 26 is preferably
further reduced by an at least substantially solid lubricant
composition 143 that is impregnated in the fabric of the bottom ply
136 and is proximate the bottom surface 142. As used herein, the
term "solid" means that the solvents employed within the
corresponding liquid lubricant composition, from which the solid
lubricant composition 143 has been formed, have been substantially
removed, such as by volatization and the like. The solid lubricant
composition 143 is preferably a mixture, and most preferably is a
substantially uniformly dispersed mixture. In FIG. 4, the solid
lubricant composition 143 is schematically illustrated by stippling
(i.e., dots and flicks) in the bottom ply 136.
[0040] In accordance with the exemplary embodiment of the present
invention, the solid lubricant composition 143 preferably includes
a mixture of two or more relatively higher viscosity lubricants
optionally along with one or more relatively lower viscosity
lubricants, with the lower viscosity lubricant(s) having lower
viscosity than the higher viscosity lubricant(s). The mixture of
two or more higher viscosity lubricants within the solid lubricant
composition 143 preferably includes a mixture of two or more waxes.
The mixture of two or more waxes preferably includes at least one
vegetable wax and at least one mineral wax. Exemplary vegetable
waxes include carnauba wax, candelilla wax, bayberry wax and wax
derived from sugar cane. In accordance with the exemplary
embodiment, the vegetable wax is carnauba wax. Exemplary mineral
waxes include earth waxes, such as ozocerite, ceresin and montan
waxes, and petroleum waxes, such as paraffin and microcrystalline
wax. In accordance with the exemplary embodiment, the mineral wax
is paraffin wax.
[0041] The higher viscosity lubricant mixture within a first
version of the solid lubricant composition 143 preferably includes
at least about 30 weight percent vegetable wax, based on the weight
of the solid lubricant composition ("bosc"). More specifically, the
first version of the solid lubricant composition 143 preferably
includes from about 30 weight percent to about 70 weight percent
vegetable wax, bosc. Even more specifically, in accordance with the
exemplary embodiment of the present invention, the first version of
the solid lubricant composition 143 includes about 50 weight
percent vegetable wax, bosc.
[0042] The higher viscosity lubricant mixture within the first
version of the solid lubricant composition 143 preferably includes
no more than about 70 weight percent mineral wax, bosc. The first
version of the solid lubricant composition 143 preferably includes
from about 30 weight percent to about 70 weight percent mineral
wax, bosc. Even more specifically, in accordance with the exemplary
embodiment of the present invention, the first version of the solid
lubricant composition 143 includes about 50 weight percent mineral
wax, bosc.
[0043] Pre-formed higher viscosity lubricant mixtures suitable for
use in the present invention are readily commercially available.
For example, one commercially available higher viscosity lubricant
mixture is available from S.C. Johnson of Racine, Wis. under the
trade name Johnson Paste Wax.TM.. Johnson Paste Wax.TM. includes
carnauba wax, paraffin wax, and a petroleum distillate solvent.
[0044] As noted above, the solid lubricant composition 143
optionally includes at least one lower viscosity lubricant.
Suitable lower viscosity lubricants include silicones, mineral
oils, polyglycols, and mixtures thereof. In accordance with the
exemplary embodiment of the present invention, the lower viscosity
lubricant is a silicone lubricant or a mixture of silicone
lubricants. In accordance with the exemplary embodiment of the
present invention, the silicone lubricant is a polysiloxane,
particularly a polydimethlysiloxane. One exemplary silicone
lubricant is Dow Corning 200 Fluid, commercially available from the
Dow Corning Corporation of Midland Mich.
[0045] The lower viscosity lubricant can be included in the solid
lubricant composition 143 in any amount providing sufficient
lubricity without detrimentally impacting the cohesion of the
resulting solid lubricant composition 143. Lower viscosity
lubricants generally exhibit a lower coefficient of friction than
higher viscosity lubricants. However, lower viscosity lubricants
can impact coating cohesion/adhesive properties. Consequently, a
second version of the solid lubricant composition 143 preferably
includes significantly greater amounts of the higher viscosity
lubricant than the lower viscosity lubricant. For example, the
weight ratio of the higher viscosity lubricant mixture to the lower
viscosity lubricant may be 2:1 or higher, such as a ratio of about
2.3:1.
[0046] Accordingly, the second version of the solid lubricant
composition 143 preferably includes no more than about 40 weight
percent of the lower viscosity lubricant, bosc. More specifically,
the second version of the solid lubricant composition 143
preferably includes from about 20 to 40 weight percent of the lower
viscosity lubricant, bosc. Even more specifically, in accordance
with the exemplary embodiment of the present invention, the second
version of the solid lubricant composition 143 includes about 29 to
30 weight percent of the lower viscosity lubricant, bosc.
[0047] The second version of the solid lubricant composition 143
incorporating the optional lower viscosity preferably includes from
about 30 to 70 weight percent vegetable wax, from about 30 to 70
weight percent mineral wax and from about 20 to 40 weight percent
low viscosity lubricant, bosc. More specifically, the second
version of the solid lubricant composition preferably includes
about 35 weight percent vegetable wax, about 35 weight percent
mineral wax, and about 30 weight percent low viscosity lubricant,
bosc. Even more specifically, the second version of the solid
lubricant composition 143 preferably includes about 36 weight
percent vegetable wax, about 35 weight percent mineral wax, and
about 29 weight percent low viscosity lubricant, bosc.
[0048] In accordance with the exemplary embodiment of the present
invention, the solid lubricant composition is formed from a liquid
lubricant composition that is applied to, e.g. coated onto, the
bottom ply. The solvents are then removed from the liquid lubricant
composition, typically by drying and the like, preferably resulting
in a layer of the solid lubricant composition 143 substantially
covering at least a portion of the outermost surface of, and
substantially impregnated into, the fabric of the bottom ply
136.
[0049] The liquid lubricant composition may be formed by dispersing
or dissolving appropriate amounts of the higher viscosity lubricant
mixture and the optional lower viscosity lubricant in solvent. The
solvent may be any organic solvent capable of dispersing the higher
viscosity lubricant mixture and optional lower viscosity lubricant.
The liquid lubricant composition is preferably formed by initially
combining the higher viscosity lubricant mixture and the optional
lower viscosity lubricant with the solvent(s) and agitating the
mixture at high speed for a suitable amount of time, such as about
5 minutes.
[0050] In accordance with the exemplary embodiment of the present
invention, the first version of the solid lubricant composition 143
is formed from a first version of a liquid lubricant composition,
and the second version of the solid lubricant composition 143 is
formed from a second version of a liquid lubricant composition.
Each of the first and second versions of the liquid lubricant
composition preferably include an initial lubricant composition
which is a mixture that preferably consists essentially of carnauba
wax, paraffin wax and a petroleum distillate solvent. In accordance
with the exemplary embodiment of the present invention, a suitable
initial lubricant composition is available from S.C. Johnson of
Racine, Wis., under the trade name Johnson Paste Wax.TM. That is,
Johnson Paste Wax.TM. includes carnauba wax, paraffin wax, and a
petroleum distillate solvent.
[0051] In accordance with the exemplary embodiment of the present
invention, the second version of the liquid lubricant composition
is preferably a substantially uniformly dispersed mixture
including: the initial lubricant composition in an amount of about
64 weight percent, based on the weight of the liquid lubricant
composition ("bolc"); a solvent, which is preferably mineral
spirits, in an amount of about 31 weight percent, bolc; and the
lower viscosity lubricant, which is preferably liquid silicone
lubricant, in an amount of about 5 weight percent, bolc. In
accordance with the exemplary embodiment of the present invention,
the first version of the liquid lubricant composition is preferably
a substantially uniformly dispersed mixture including: the initial
lubricant composition in an amount of about 67 weight percent,
bolc; and a solvent, which is preferably mineral spirits, in an
amount of about 33 weight percent, bolc.
[0052] The liquid lubricant composition is preferably applied to
the belt material using the equipment and processes described in
conjunction with the comparative embodiment described above. More
particularly, a coater, such as a knife coater, is used to apply
the liquid lubricating composition to the fabric of the bottom ply
of the belt material and the coated belt material is subsequently
dried. In accordance with the exemplary embodiment of the present
invention, the various solvents within the liquid lubricant
composition are volatilized in the drying oven 52 (FIG. 3)
following the coating process, so that the resulting solid
lubricant composition 143 is impregnated in the fabric of the
bottom ply 136. The solid lubricant composition 143 is preferably
at least substantially in solid form at room temperature (e.g.,
72.degree. F.). The coated belt 121 preferably has solid lubricant
composition 143 coat weight ranging from about 1 oz/sq. yd to about
5 oz/sq. yd. Most preferably, the solid lubricant composition 143
is present in the belt 121 in an amount of about 2.5 oz/sq. yd.
[0053] Numerous advantages are associated with the belt 121 of the
exemplary embodiment of the present invention. Advantageously, the
belt 121 can be lubricated prior to splicing the belt, no
relubrication is needed for the life of the belt, the belt lasts
longer than conventional comparable belts, and the belt is
"heavy-duty" such that it is well suited for treadmills used in
spas or health clubs. As an example, the chart of FIG. 5
illustrates the performance of the belt 121 of the exemplary
embodiment of the present invention as compared to a comparable
belt. For FIG. 5, the two belts were run under substantially
identical conditions, with the only difference being the
differences in the belts themselves.
[0054] The endless belts 121 of the exemplary embodiment of the
present invention are preferably used in treadmills; nonetheless,
the belts 121 can also be used in a wide range of other
applications in which belts are used. In one example, the endless
belt 121 is used in a treadmill with an unwaxed deck (e.g., see the
deck 26 in FIG. 1). In another example, the belt 121 is used in a
treadmill with a waxed deck (e.g., see the wax 32 on the deck 26 in
FIG. 1), but advantageously the quantity of wax on the deck can be
substantially reduced as compared to the prior art. Since the
lubricated belts 121 are used with un-waxed decks, or decks with
substantially reduced wax quantity, wax will not substantially
accumulate on rollers of the treadmills.
[0055] Numerous other advantages are associated with the belts 121
of the exemplary embodiment of the present invention. For example,
since the belt lubricant 143 of the exemplary embodiment is at
least substantially solid after drying, migration of the lubricant
143 is substantially precluded. Also, due to the substantially
solid nature of the lubricant 143, it can advantageously be applied
to rolls of belting material before sections are cut therefrom and
spliced, because the solid lubricant does not substantially
interfere with the splicing/adhesion. Additionally, the fabric of
the bottom ply 136 is preferably saturated with the lubricant 143,
with the lubricant intimately impregnated in the fabric bottom ply,
and not just on the bottom surface, so that any loss of lubricant
from the belt is insubstantial. The small proportion of silicone
lubricant in the lubricant composition 143 improves lubrication,
but the proportion is preferably sufficiently small so that the
lubricant composition 143 is still substantially solid at room
temperature. Advantageously, the small proportion of silicone
lubricant does not substantially migrate or substantially interfere
with belt splicing.
[0056] Many modifications and other embodiments of the inventions
set forth herein will come to mind to one skilled in the art to
which these inventions pertain having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. For example, the lubricants of the present invention can
be applied to many different types of belts, can be used on items
other than belts, and can be considered to be isolated articles of
manufacture (e.g., separate from any belts, treadmills, etc.). For
example, it is within the scope of the present invention for the
lubricant 143 of the present invention to be used with (e.g.,
applied to and preferably impregnated into the bottom surfaces of)
conventional treadmill belts. Likewise, the belts of the present
invention can be used in combination with many different types of
lubricants or can be considered to be isolated articles of
manufacture (e.g., separate from any lubricant etc.).
[0057] It is to be understood that the inventions are not to be
limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included
within the scope of the appended claims. Although specific terms
are employed herein, they are used in a generic and descriptive
sense only and not for purposes of limitation.
* * * * *