Note: Descriptions are shown in the official language in which they were submitted.
~' . lZ~8573
, . .
BACKGROUND OF THE INVENTION
This invention relates to an improved wire supported
~j ,
hose, such as a vacuum hose, and to the method of making it.
,More specifically, the invention relates to a hose having a
`spirally wound reinforcing wire which is laminated or encapsu-
lated between layers of rubberized fabric which serve to
capture the wire in the hose body and prevent failure due to
the wire moving in the rubber body. Fabric buffers are
necessary because the wire will not bond well to rubber.
The spiral windings of this fabric-wire l~minate do not abut
or overlap, thus avoiding any loss of flexibility or elasticity
in the hose due to the presence of a continuous ~ayer of
fabric which is less ~lexihle and elastic than the hose
bod~.
Prior to this invention wire supported hoses were
~subject to failure due to wear caused by movement of the
reinforcing wire, necessary to prevent collapse of the hose
under vacuum, against the rubber (or similar relatively soft
material) of the hose body. Many approaches have been taksn
to eliminate this wear by application o some type of wear
strip on or around the wire, but these approaches have not
been entirely satisfactory because the reduction in wear was
gained at the loss of flexibility and elasticity of the
hose.
For example, in U.S. Patent 2,722,263, a plastic
tape is applied around the reinforcing wire~ However, this
tape is wound in an overlapping fashion around the hose,
forming a continuous layer having less elasticity and
flexibility than the hose itself. Moreov~r, such a tape is
not as effective as fabric in capturing and holding the
wire. Another approach is shown in U.S. Patent 3,~46,202
wherein a wearstrip is wound over the reinforcing wire and
is bonded in place with glue. There is no buffer provided
. . ,
- ' ` ` lZ(~3573
between the wire and the inner sleeve of the hose, and the
bonding in place of the wear strip necessarily limits the
overall elasticity and flexibility of the hose to that of
' the bonded wearstrip. In the present invention, one or more
rubberized fabric wearstrips are applied to completely
encapsulate the wire. This wire-fabric laminate is then
spirally wound onto the inner sleeve of the hose without
overlapping to form a continuum. Thus, the relative inflexibility
and inelasticity of the fabric wear strips do not materially
1. !
detract from the elasticity and flexibility of the finished
, hose.
SUMM~RY OF THE I21VENTION
This invention consist~ of a method for making an
elastic, flexible wire-reinforced vacuum hose and of the
resultant hose. The invention avoids wear due to movement
of the reinforcing wire and does so without sacrificing
elasticity and flexibility of the hose.
other objects and advantages of the invention will
be readily understood from the following detailed description
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig~ 1 is a schematic view of the apparatus for
practicing the method of this invention.
Fig. 2 i8 a detail view of block 20 of Pig. 1.
Fi~. 3 is a sectional view of the product of this
invention at an intermediate stage of manufacture.
Fig. 4 is a sectional view of the completed product
of this invention.
' Fig. 5 is a detail view of an alternate embodiment
of block 20 of Fig. 1.
Fig. 6 is a detail view of a second alternate
embodiment of block 20 of Fig. 1.
. lZ~3S73
DETAILED DESCRIPTION OF THE PREFERRED
: EMBODIMENT OF THE INVENTION__ _
The most ~ignificant advantage of this invention
is that it provides a reinforced hose resistant to movement
of the reinforcing wire but without loss of elasticity and
flexibility. This advantage ? S achieved by spirally winding
the reinforcing wire onto the hose while simultaneously
encapsulating the wire between strips of fabric which serve
to bond the wire to the rubber. Withou~ the fabric, the
wire will not bond well ~o the rubber and consequently will
move about and break down the adhesion between the wire and
i' the hose.
A schematic representation of a machine 10 to
practice this invention i8 shown in Fig. 1. An inner sleeve
of polymeric material 30, such as gum rubber is formed
around a mandrel 11. This sleeve may be formed by any of
the well-known technique~ of extrusion, spiral winding from
a relatively narrow roll of material, or flat winding from a
roll of material whose width is substantially the circumference
of the fini~hed product. In Fig. 1 the inner sleeve has
already been placed on the mandrel.
Afker this inner sleeve ha~ been allowed to set,
the reinorcing element is applied. Spools 12 and 13 hold
' relatively narrow tapes of fabric. Spool 14 holds the
, i ,
reinforcing wire. These ~pools are mounted on carriage 15 f
., ,
~I which i5 driven along tracks 16 at a speed synchronized with
!l I
the turning speed of mandrel 11. Thus, the carriage moves a
fixed distance down the longitudinal axis of the mandrel for
each revolution of the mandrel, causing the reinforcing
element to be spirally wound about the inner sleeve.
lZ~3573
As the carriage 15 advances synchronously with the
revolution of mandrel 11 carrying inner sleeve 30, fabric
tapes 12' and 13' and reinforcing wire 14' are drawn from
their respective spools through guide block 20 and spirally
wrapped around sleeve 30. Tension on tapes 12' and 13'
causes them to encapsulate wire 14' as shown in Fig. 3. The
combination of tapes 12' and 13' and wire 14' forms reinforcing
element 31, Reinforcing element 31 is spirally wound onto
inner sleeve 30 so that no two wraps abut or overlap, thus
avoiding a continuous, relatively inelastic reinforcing
layer in the hose.
Guide block 20 consists of three plates having
aperture,s therethrough to allow for passage of the reinforcing
tapes 12' and 13' and wire 14'. The upper aperture 21 has a
rectangular cross section and is adapted to guide passage of
tape 12'. The lower aperture 22 is identical to aperture 18
and guides tape 13'. The center aperture 23 has a circular
cross section and guides reinforcing wire 14'. It is after
passage through guide block 20 that tension on tapes 12' and
13' causes them to encapsulate wire 14'.
Alternate illustrative embodiments of block 20 are
shown in Figs. 5 and 6. Using either of these alternate
blocks results in a substantially identical end product.
However, the reinforcing laminate 50 i6 formed from a single
ribbon of rubberized fabric which is curled as it passes
through the block's aperture so as to encapsulate the wire
51. Tension on the ribbon through the block causes close
wrapping of the ribbon about the wire with any of the three
embodiments.
lZC~8573
After reinforcing element 31 is spirally wound
down the length of inner sleeve 30, the ends of the wire are
tied down in well-known fashion. The reinforced inner
sleeve is then covered with another layer of pol~meric
material 40, such as gum rubber. Cure tape is then wrapped
around the hose, the assembly is vulc~nized, and the cure
tape is removed. The result is a finished reinforced vacuum
hose resistant to wear and with no significant loss of
flexibility and ela~ticity. As shown in Fig. 4, tapes 12'
~nd 13' completely encapsulate wire 14' and bond it securely
to inner sleeve 30 and outer layer 40. In actual practice,
these layers are virtually indistinguishable after vulcaniza-
tion, which merges the layers into one mass.
