U.S. patent number 3,724,284 [Application Number 05/143,993] was granted by the patent office on 1973-04-03 for v-belt and method of forming same.
This patent grant is currently assigned to AB Sveriges Forenade Trikafabriker. Invention is credited to Kjell Eng, Sven-Olof Salomonsson.
United States Patent |
3,724,284 |
Eng , et al. |
April 3, 1973 |
V-BELT AND METHOD OF FORMING SAME
Abstract
This V-belt is provided with a textile jacket covering the main
body of the belt, and the textile jacket is in the form of a warp
fabric knit of thermoplastic synthetic yarns. This fabric includes
interconnected stitch chains forming wales in the knit fabric and
is cut lengthwise, parallel to the wales into strips which are
applied to the belt body with the wales extending in the
longitudinal direction of the belt. The textile jacket is
vulcanized to the belt body and completely surrounds the belt
profile.
Inventors: |
Eng; Kjell (Kattilstorp,
SW), Salomonsson; Sven-Olof (Bramhult,
SW) |
Assignee: |
AB Sveriges Forenade
Trikafabriker (Boras, SW)
|
Family
ID: |
22506598 |
Appl.
No.: |
05/143,993 |
Filed: |
May 17, 1971 |
Current U.S.
Class: |
474/265; 156/140;
474/267 |
Current CPC
Class: |
F16G
5/04 (20130101) |
Current International
Class: |
F16G
5/00 (20060101); F16G 5/04 (20060101); F16g
005/00 () |
Field of
Search: |
;74/234,237 ;156/137,140
;161/89,91 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Myhre; Charles J.
Assistant Examiner: McKenzie, Jr.; Frank H.
Claims
That which is claimed is:
1. A power transmission V-belt comprising an elongate belt body and
a textile jacket covering said belt body, said jacket comprising a
warp knit fabric having interconnected stitch chains forming wales
extending longitudinally of the knit fabric, said knit fabric being
heat set to control the amount of elongation thereof, said knit
fabric being embedded in elastomeric material and vulcanized to
said belt body, said textile jacket completely surrounding the
profile of said belt body with the knit wales of said warp knit
fabric extending longitudinally of and parallel with said belt body
to provide sufficient stretch and recovery that said textile jacket
conforms to the configuration of said belt body as the same passes
around drive pulleys and the like.
2. A power transmission V-belt according to claim 1 wherein said
textile jacket is knit of thermoplastic synthetic warp yarns.
3. A power transmission V-belt according to claim 2 wherein said
warp yarns are within the range of about 40 to 120 denier.
4. A power transmission V-belt according to claim 2 wherein said
thermoplastic synthetic yarns are continuous filament
polyamide.
5. A power transmission V-belt according to claim 2 wherein said
thermoplastic synthetic yarns are continuous filament
polyester.
6. A power transmission V-belt according to claim 1 wherein said
warp knit fabric is formed of two sets of thermoplastic synthetic
warp yarns.
7. A power transmission V-belt according to claim 6 wherein said
warp yarns of each set are knit together in stitch loops in every
wale, and wherein the warp yarns of one set are lapped back and
forth between immediately adjacent wales and the warp yarns of the
other set are lapped back and forth between spaced wales to form
relatively long laps diagonally extending across at least one
wale.
8. A method of forming a power transmission V-belt including an
elongate belt body and a textile jacket covering the belt body,
said method comprising the steps of knitting a fabric of
thermoplastic synthetic warp yarns while forming wales of
interconnected stitch chains extending longitudinally of the knit
fabric, heat setting the knit fabric while being held under
controlled tension, slitting the knit fabric along lines extending
parallel to the wales of the fabric to form strips of predetermined
width, applying a strip of the knit fabric to the outer profile of
the belt body to completely cover the same and with the wales
extending parallel to the length of the elongate belt body and
vulcanizing the knit fabric jacket to the belt body.
9. A method according to claim 8 including the step of treating the
knit fabric to improve its ability to adhere to the elastomeric
material without substantially changing the flexibility
characteristics of the knit fabric.
10. A method according to claim 8 including the step of
impregnating the knit fabric with an elastomeric material, prior to
slitting the fabric to form the strips.
Description
This invention relates generally to a power transmission V-belt and
method of forming same, and more particularly to an improved V-belt
including an elongate body and a textile jacket or cover of a warp
knit fabric with the wales of the fabric extending in the
longitudinal direction of the belt to provide sufficient stretch
and recovery that the textile jacket conforms to the configuration
of the belt body as the V-belt passes around pulleys and the
like.
Most V-belts currently being manufactured include an elastomeric
core or body having parallel reinforcing threads or cords embedded
therein and having a textile jacket or covering vulcanized to the
outer surface and covering the belt body. The textile jacket or
covering is usually formed of a woven fabric. In order to obtain
the maximum amount of elasticity or stretchability in this woven
fabric, it has been the practice to cut strips of the woven fabric
at an angle of approximately 45.degree. to the warp and weft yarns;
i.e., along the bias of the fabric. The diagonal cutting of woven
fabric to form this type of textile jacket results in waste
material and limits the length of the strips which may be cut from
the fabric. Also, the woven fabric does not provide a long wear
life because the diagonally extending warp and weft yarns do not
have the desired amount of stretch and recovery and the textile
jacket tends to become worn and frayed after some use of the
V-belt.
With the foregoing in mind, it is an object of the present
invention to provide an improved power transmission V-belt and
method of forming the same which includes a textile jacket formed
of a warp knit fabric to provide sufficient stretch and recovery
that the jacket and V-belt has a long wear life.
In accordance with the present invention, the warp knit fabric is
cut into longitudinal strips in the same direction in which it was
knit; i.e., parallel to the knit wales so that very long continuous
strips of the knitted fabric may be provided. The warp fabric is
knit of thermoplastic synthetic yarns and is heat set to control
the amount of elongation or stretchability. Also, the knit fabric
is treated to improve its ability to adhere to an elastomeric
material with which it is impregnated, such as rubber or the like.
A strip of the warp knit fabric is applied to the body of the
V-belt and completely surrounds the same with the wales of the
fabric extending longitudinally and parallel with the belt body.
The warp knit fabric jacket is vulcanized in this position so that
the jacket becomes a permanent part of the V-belt.
The thermoplastic synthetic yarns of the warp knit fabric are
preferably of the continuous filament type and provide longer
wearability. Also, the stretch and recovery of the textile jacket
of the V-belt corresponds more nearly to the stretch and recovery
of the elastomeric body of the belt so that the tendency for
separation of the jacket from the belt body is reduced. The
thermoplastic synthetic yarns forming the warp knit fabric provide
greater strength than yarns formed of spun staple length fibers so
that it is possible to manufacture smaller V-belts having the
strength and wearing qualities of larger V-belts of the type having
a jacket of woven textile fabric.
This invention is also concerned with a method of forming an
improved V-belt which comprises the steps of knitting thermoplastic
synthetic yarns to form a warp knit fabric having interconnected
stitch chains forming longitudinally extending wales, and slitting
the knit fabric along lines extending parallel to the
longitudinally extending wales to form strips of predetermined
width. The treated and heat set knit fabric or the heat set knit
strips are impregnated with a suitable elastomeric material, such
as rubber or the like, and a knit strip is applied to the belt body
while overlapping opposed sides of the strip to completely surround
the belt body. The covered belt is then vulcanized so that the
textile jacket of warp knit material becomes a unitary part of the
V-belt.
Other objects and advantages of the present invention will become
apparent in connection with the following description of the
drawings in which:
FIG. 1 is an isometric view of a typical V-belt and including a
textile covering or jacket formed in accordance with the present
invention;
FIG. 2 is an enlarged cross-sectional view through the V-belt shown
in FIG. 1, being taken substantially along the line 2--2, and
illustrating a portion of the V-belt in elevation; and
FIG. 3 is a somewhat schematic view of a fragmentary portion of the
warp knit fabric illustrating the manner in which it is formed with
laps interconnecting the stitch chain wales of stitch loops, the
wales extending between the bottom and the top of the fabric shown
in FIG. 3.
The power transmission V-belt B generally includes an elongate belt
carcass or body 3 and a surrounding textile jacket or covering,
broadly indicated at 4. The belt body 3 is preferably formed of
elastomeric material, such as rubber, and is usually provided with
reinforcement threads or yarns 2 embedded therein and extending in
the longitudinal direction.
The cover or jacket 4 is formed of a strip of warp knit fabric
having opposed longitudinal edges, indicated at 5 and 6 in FIG. 2,
which overlap along the outer radial face of the belt. The strip of
warp knit fabric is cut from a suitable type of warp knit fabric,
such as that illustrated in FIG. 3. This fabric is knit of two sets
of continuous filament thermoplastic synthetic warp yarns Y-1 and
Y-2 to form longitudinally extending wales of interconnected stitch
loops forming chains, indicated at W-1 through W-4.
During the knitting of the fabric, the set of warp yarns Y-1, one
of which is speckled in FIG. 3 for purposes of identification,
forms stitch loops in each course and the yarns are lapped back and
forth between spaced wales and across one wale to form relatively
long diagonally extending laps. The set of warp yarns Y-2, one of
which is illustrated as being striped in FIG. 3, forms stitch loops
in successive courses and the yarns are knit together in plated
relationship with stitch loops of the yarns Y-1. The yarns Y-2 are
lapped back and forth between immediately adjacent wales to form
relatively short diagonally extending laps.
This type of warp knit fabric is easily adaptable for heat setting
so that it contains the proper amount of elasticity in its
longitudinal direction for use as a covering for V-belts and the
like and has good recovery from stretch so that the outer and inner
peripheral surfaces of the V-belt will readily conform to the
configuration of drive elements, such as pulleys or the like around
which the belt is entrained. The elasticity of this particular type
of knit fabric is sufficient that the outer peripheral surface of
the V-belt may stretch while the inner peripheral surface contracts
as the belt passes around the drive elements with which it
operates. The yarns forming the warp yarn sets Y-1 and Y-2 are
preferably continuous filaments of a thermoplastic synthetic
material, such as polyamide (nylon) or polyester (Dacron). These
types of synthetic thermoplastic yarn have very high breaking
strength and have a long wear life as they are continuously
stretched and flexed during use of the V-belt.
To prepare the warp knit fabric for use as covering for V-belts and
the like, the fabric is preferably heat set while being held under
the desired degree of tension to control the amount of elongation
or stretchability in the fabric. A suitable treatment is preferably
applied to the fabric to improve its ability to adhere to rubber.
This treatment agent may be in the form of isocyanat which is
applied to the fabric prior to the heat setting. The isocyanat is
applied in liquid form with a solvent to provide the proper
consistency so that the desired amount of the isocyanat is applied
to the fabric to cause the elastomeric material to adhere thereto.
The quantity of isocyanat applied to the fabric is below the level
which would cause stiffening of the fabric and below the level
which would cause the yarns of the stitch loops to stick together.
The heat set and treated fabric is then immersed in an elastomeric
solution, such as liquid rubber, and then dried before it is cut
along longitudinally extending lines, such as indicated by the
dash-dot line 7 in FIG. 3. The slit lines extend walewise so that
the wales of the fabric extend longitudinally of each strip. The
fabric is cut into strips of a predetermined width which is
sufficient to wrap around and cover the body 3 of the particular
V-belt to which it is to be applied. Opposite side edges of the
strip overlap a small amount on the outer peripheral surface of the
V-belt (FIG. 2).
If desired, the heat set and treated warp knit fabric may be slit
before it is impregnated with the elastomeric solution. In this
case, the fabric strips are immersed in the elastomeric solution,
such as liquid rubber, and then dried in any suitable manner. In
either instance, the V-belt is vulcanized with the impregnated warp
knit jacket positioned thereon so that the textile jacket becomes a
permanent and unitary part of the V-belt.
The improved V-belt is extremely strong and wear-resistant and may
be safely subjected to temperature ranges which are well above the
temperatures to which V-belts are normally exposed during
operation. The enhanced flexibility, strength, stretchability and
recovery of the textile jacket aid in preventing the separation of
the covering jacket from the belt body during use to thereby
increase the wear life of the belt. Although other types of warp
knit stitch constructions or patterns may be utilized for forming
the knit fabric illustrated in FIG. 3, it has been found that this
particular stitch construction provides the amount of strength,
flexibility, stretchability and recover required for most types of
V-belts. In order to provide the desired degree of flexibility and
wearability to the V-belt, it is preferred that the warp knit
fabric be formed of warp yarns of relatively fine denier. For
example, it is preferred that the yarns Y-1 and Y-2 be within the
range of about 40 to 120 denier.
In the drawings and specification, there has been set forth a
preferred embodiment of the invention, and although specific terms
are employed, they are used in a generic and descriptive sense only
and not for purposes of limitation.
* * * * *