CA1054535A

CA1054535A - High pressure reinforced hydraulic hose

Info

Publication number: CA1054535A
Application number: CA269,939A
Authority: CA
Inventors: Charles E. Grawey
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1976-04-02
Filing date: 1977-01-18
Publication date: 1979-05-15
Also published as: DE2713342C2; DE2713342A1; JPS52120415A; GB1532849A; FR2346627B1; FR2346627A1

Abstract

A B S T R A C T
Hydraulic circuits having flexible hydraulic hoses forming part of the circuits are currently being operated at pressures in excess of 3,000 psi, and such circuits are often limited in their operating pressure by the burst strength of the hydraulic hose. By constructing a hollow core structure that forms the conduit and which serves as the foundation upon which the reinforcing is applied, with a two-layer tape composed of a layer of fabric and a layer of elastomer, which tape is then wound on a mandrel in a helically overlapping relationship with the fabric on the outside, an improved hose can be obtained after the rein-forcing is applied. An increase in burst strength can be obtained in such a hose where wire cable is employed as the reinforcing in place of monofilament wire reinforcing, when the cable is formed (twisted) as it is applied, to achieve a more uniform tension on each of the strands forming the cable encircling the core structure.

Description

~S~S;~5 Background of the Invention High pressure wire reinforced hydraulic hose is typically used on a variety of machines, including earth-working machines, to provide a flexible connection between several moving parts of a common hydraulic circuit employed on or with the machine. Most often, such hoses are em-ployed in circuits and articulated machines or machines wherein one part must move relative to the other part.
Typical reinforced hydraulic hose structures utilized in such applications are illustrated in U.S. Patent 2,128,814 issued to Gish; U.S. Patent 3,312,528 issued to Haas; U.S.
Patent 3,357,456 issued to Grawey et al; and U.S. Patent 3,866,633 issued to Taylor.
All of the hose structures described in the afore-mentioned patents include a hollow elastomer core on which successive cylindrical plies of wire reinforcing are concentrically applied to contain the radial and axial pressures developed within the hose when it is placed in service at high pressures in the range of 3,000 psi or greater. To some extent, the burst strength of these hoses can be increased by adding additional reinforcing plies (within limits) and in most cases, an even number of rein-forcing plies must be used so that the angular wrap of opposite hand of two adiacent plies balance one another.
One of the critical areas of construction of such hydraulic hose is the core structure. With the exception of the aforementioned Grawey et al Patent 3,357,456, the core structures in such hoses have been typically extruded as a cylindrical tube to obtain a continuous circular wall for the hose and to provide the foundation upon which the ...

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~54535 wire reinforcing can be applied to complete the hose. Typ-ically, the core is protected with a layer of fabrics as mentioned in the above patents, before the reinforcing is applied.
The above Grawey et al patent teaches the prepara-tion of an improved core in such whereln a laminated tape composed of at least one of elastomer and at least one layer fabric is wrapped on a mandrel, usually in a helical overlapping relationship, to form a core. This combination elastomer and fabric core generally has a greater capacity to restrict the embedding or "biting" of the reinforcing wires into the core structure and therefore helps achieve greater concentricity of the first ply of cylindrical reinforcing wrapped on the core structure. Since each cylindrical reinforcing ply forms the base for the subsequent cylindrical reinforcing ply, an overall improvement in hoæe structure is thus achieved. U.S. Patent 3,866,633 attempts to appropriate the teachings of the Grawey et al patent by an extruded core structure which utilizes aligned fibers in an extruded cylindrical core.
According to the invention there is provided a reinforced hose comprising a cylindrical core composed of a helical winding of a laminate having solely a single elastomer layer and a fabric layer, the elastomer layer forming the inner layer of the core; a layer of bonding elastomer on the outer, fabric surface of the core; a first cylindr$cal ply of a plurality of substantially inextensible reinforcing elements wound around the layer of bonding elastomer with sufficient tension on each of the elements to penetrate at least partially ~;
the bonding elastomer layer in a series of side-by-side helical convolutions to form a first cylindrical reinforcing ply having . i~ .

)5~535 a wall thickness substantially equal to the diameter of the elements; a second cylindrical ply of substantially inextensible reinforclng elements wound around the first cylindrical reinforcing ply in a series of helical convolutions to form a second cylindrical reinforcing ply having a wall thickness substantially equal to the diameter of the elements, the first and second cylindrical plies being arranged so that their respective helical convolutions are of opposite hand; and a cylindrical elastomer jacket encircling the resulting reinforced core, the jacket and reinforced core being vulcanized in an integral unit.
The invention includes a method of making wire :
reinforced hose comprising the steps of forming a laminate having a fabric layer and an elastomer layer on the outer surfaces of the laminate; wrapping the laminate on a mandrel with the elastomer layer thereagainst to form a hollow core with an outer fabric surface; covering the outer fabric ~:
surface of the resulting core with a layer of bonding elastomer having bonding characteristics compatible with wire reinforcement; winding under tension on the bonding elastomer a plurality of substantially inextensible rein~
forcing elements in side-by-side helical convolutions to form a first cylindrical reinforcing ply having a ply -thickness equal to the diameter of the reinforcing elements;
winding under tension around the first cylindrical rein- :
forcing ply a plurality of substantially inextensible reinforcing elements in side-by-slde helical convolutions -which cross angularly the helical convolutions of the first ply to form a second cylindrical reinforcing ply;
encircling the resulting reinforced core structure with :. , .:,: . . . . i : :
- : .... . . ,:,, . ., . , ,.: ~ -: , -~5~5;~5 elastomer to form an outer jacket for the hose; and vulcan-izing the elastomers, reinforcing elements and core as an integral unit.
The present invention is thus able to provide a stiffer "base" on which to wrap the first ply of wire, which improves the wire lay in this ply. With improved wire lay in this ply and subsequent plies, stress distribution during hose preparation should be more uniform between the wires -in each individual ply, resulting in a higher burst pressure approaching the theoretical.
The improved laminated core structure has improved "knit lines" in a helically wrapped tape forming the core.
In addition, through the utilization of a two-layered tape, it is possible to eliminate some of the partial cure that results in multi-layered tapes as a result of viscous shear in the rubber, which causes localized heat buildup and partial cure of the heat sensit~ve compounds therein.
All of the elastomers should be in an uncured state and normally bond stock is also placed between the two re-inforcing plies to insulate them from one another, and the second reinforcing ply is of opposite hand (an angle equal but opposite the spiral wrap of the first reinforcing ply).
The reinforcing elements can be composed of multi-strand wire cables that are twisted into a cable configuration as -the element is wound.
Two examples of hoses according to the invention will now be described with reference to the accompanying drawings, in whqch:

1~54S35 Fig. 1 is a schematic illustrating the formation of the two-layered tape, i.e., fabric and uncured elastomer, showing the clanedar rolls and fabric supply reel;
Fig. 2A is a perspective of the two-layered tape with parts broken away to show the relationship between the fabric and elastomer layers;
Fig. 2B is a section further detailing the structure of the two-layered tape;
Fig. 3 is a perspective illustrating the wrapping of the two-layered tape onto a mandrel in an overlapping relationship;
Fig. 4 is a perspective illustrating the applica-tion of an elastomer bond stock layer onto the core formed by the wrapping process illustrated in Fig. 3;
Fig. 5 is a schematic illustration illustrating -the application of cable reinforcing elements onto th-e hose core wherein the cable reinforcing elements are composed of multiple monofilament wires separately tensioned and twisted into a cable as they are being wound; ;
Fig. 6 is an elevation partly in section illustrating the wrapping of the two-layered tape onto a mandrel to form :
the core structure;
Fig. 7 illustrates a conventional winding head for wrapping a layer of monofilament reinforcing elements onto the structure formed according to this invention; and Fig. 8 illustrates, partially in section, a multiple winding deck for hose manufacturing in a schematic fashion.

.. '':. . :' ' 16~S4S35 Description of a Preferred Embodiment In reference to this invention, it is believed that the Grawey Patent 3,357,456 is the most similar to the instant invention; however, the instant invention repre-sents a -efinement in the manufacture of the high pressure hydraulic hose described in the referenced Grawey patent.
By reference to Figs. 1 and 2, the construction of the two layer laminated tape 10 can be appreciated.
Basically, this tape can consist of a fabric layer ll and an uncured elastomer layer 12 which are formed in an integral sandwich 13 through the use of calendaring rollers 14 and 15 which convert the uncured elastomer supply "A" into an elastomer layer of uniform thickness. This uniform elastomer layer is then married to the fabric layer 11 supplied from supply reel 16, through the utilization of a compression roller 17 co-acting with calendar roll 15 to squeeze the elastomer layer 12 and the fabric layer 11 together to form an integral sandwich composed of the two layers.
In general, when the elastomer fabric sandwich 13 is formed, the fabric is physically forced into the elastomer layer 12 in a manner that portions of the elastomer layer are forced partially into the open mesh of the fabric whereby at least a friction bond, if not some adhesive bond, is obtained between the several layers. Normally when this occurs, the elastomer layer is not forced through the mesh sufficiently far to coat the outer surface of the fabric.
After the tape lO is formed, if the fabric is pulled free of the elastomer layer, the latter is left with a plurality of checks or squares where the open mesh has been imbedded therein.

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1;[)54535 It is important that the elastomer layer be some-what thicker than the fabric layer in order to achieve sufficient rubber flow when the core cured with the rein~
forcing is to "knit" all the seams particularly along the cylindrical surface of the mandrel, so that no leakage will occur through the core structure. In general, the mesh fabrics employed are fabricated of nylon or the like and have a mesh size sufficient for the elastomers on opposite sides of the fabric to interbond through the mesh openings when the core has been formed by winding the tape in a spiral overlapping relationship. Normally the fabric will have from 16-20 threads per inch for both the warp and the weft. The thickness of the fabric used is approximately 0.010 inches, and in general, the elastomer layer should be of a thickness from 0.015 to 0.050 inches. Particularly preferred is an elastomer layer having an aE-proximate uni-form thickness of 0.045 inches. --In the fabrication of the tape 10 illustrated in Fig. 1, the sandwich 13, after passing through the compres-sion step between rollers 15 and 17, is covered with a polyethylene sheet 20 which is applied to the elastomer side sandwich as it egresses from the rollers from a supply (not shown) and is applied to the elastomer layer 12 by roller 21. After the polyethylene sheet has been applied, the sandwich 13 can be slit into a uniform width to form the tape 10, which is then collected (wound) on a supply reel for subsequent use. To form the tape, the layered fabric and elastomer sheet are slit against a roller with the fabric arranged to contact the surface of the roller to achieve severance of the threads of the fabric with a ' ' ' ~ ' .' . ' -7- ~

~ 54535 minimum of displacement. In addition, in the two-layered tape, the degree of cure in the elastomer, when stored for a considerable period of time, is much easier to determine than in the three-layered tape. It is also possible to make the two layer tape by sprinkling short fiber on the surface of the elastomer in a random manner to achieve the proper fabric thickness and thereafter calendaring these two layers to achieve satisfactory adhesion between the elastomer and the fibers.
Referring to Fig. 3, it can be seen how the tape 10 is wrapped onto a mandrel 40 in a helical or spiral advancing overlapping relationship. This wrapping technique whereby the elastomer layer 12 is wound against the mandrel, leaves an outside fabric surface 41 on the exterior of the core 42 and, of course, the polyethylene sheet is stripped from the tape before it is wrapped in the described manner.
While Fig. 3 illustrates the formation of the core structure 42 according to this invention, it is normally formed in an automated process (see Fig. 6) using a tape winding deck 43 having a central aperture 44 through which the mandrel 40 is advanced while the deck is rotating. A
tape reel 45 is attached to the winding deck to revolve about the mandrel and is supported by an adjustable linkage 46 through turn buckle 47; this can adjust the angle of the tape reel so that the tape 10 can be applied in a uniform overlapping relationship as mandrel 40 advances in the direction of arrow B.
The resulting structure obtained is best illus-trated in Fig. 4 wherein the lap relationship of the tape 30 10 is illustrated when it has been wrapped in the mandrel ;~

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1~54535 40 to form the core 42. In general, at least two layers of fabric are present in the core structure in a lapping relationship since the tape is preferably wrapped with a one-half overlap as it is advanced spirally or helically along the mandrel 40. As can be seen in this figure, the elastomer is contiguous to the surface of the mandrel and as a result, the thicker elastomer layer can flow into the spiral seams 48 along the surface of the mandrel when the resulting built-up hose structure is cured or vulcanized.
Also shown in Fig. 4 is the layer of elastomer bond stock 49 which is usually applied to the fabric surface of the hose core before the first ply of reinforcing is wound thereon. This bond stock is specifically selected to give better bonding characteristics to the reinforcing wires or cables which are often brass plated to insure better bonding with the elastomer bond stock. Alternatively it can be sprayed on the surface of the core in a liquid state. The bond stock itself can be applied by wrapping the core or can be placed on the core by forming a sheet positioned along the surface of the core after it has been formed so that a longitudinal seam is formed that can be formed with a lap if desired.
To have quality high pressure hydraulic hose, it ;
is necessary for the spiral seam in the spirally wrapped core to "knit" in the area of spiral seams against the ~- -mandrel 40 so that a smooth continuous hose wall without pinholes is obtained. The thicker elastomer layer accom- -plishes this when the cure or vulcanization takes place, since it can flow into this spiral groove 48 and "knit"
the wall to provide a smooth continuous hole free liner, .",: .:

_9_ ~-~54535 without any increase in the overall thickness of the laminated tape.
Further, the core structure so obtained has a fabric surface which is properly located to better resist the biting or penetration of the reinforcing which will be subsequently applied to the hose core.
More specifically, the bond stock layer 49 is relatively soft and thus, as the reinforcing wires are wound in a spiral side-by-side convolution onto the bond stock, they will substantially penetrate the bond stock almost to the fabric surface of the core as the reinforcing elements are wound. Also these elements are tensioned so that a uniform concentric reinforcing ply can be obtained.
In reference to winding the reinforcing ply, reference is made to Fig. 7 wherein the hub of a winding deck 50 is equipped with a head 51 that has a plurality of radial holes 52 through which monofilament reinforcing elements can be threaded so that as the winding deck 50 rotates about man-; drel 40, the plurality of wires will be applied in a side-by-side series of convolutions on the surface of the bond stock. Each of the reels from which the wire is fed are tensioned to insure that all the reinforcing elements shown ~
in Fig. 7 as monofilament wires 53 each have a separate and -predetermined tension. This again insures greater concen-~ tricity in the first ply of the reinforcing when it is ; applied onto the built-up core structure 42.
As can be seen in Fig. 8, the several reinforcing plys are applied simultaneously as the mandrel 40 is advanced through a plurality of conventional winding decks 50. The core formed on the mandrel equipped with the bond ~ ' .: .
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1~5~535 :

stock 49 is advanced through the first winding deck wherein the first concentric ply 60 of reinforcing is wound onto the bond stock with the supply reels for the reinforcing elements 53 separately tensioned, (tensioning devices not shown). After the first reinforcing ply has been wound onto the core structure a layer of bond stock 61 is formed there-over and the build-up structure passes through the second winding deck which is identical to the first, but rotates in the opposite direction. ~s a result, the second ply will be angularly disposed relative to the first ply. If only two plys are to be employed the build-up structure then passes to a casing deck 62 which winds an elastomer tape on the surface of the last reinforcing ply 63 formed by the second deck. The built-up hose structure 64 can then be covered with shrink tape and subsequently cured as a unit, with the shrink tape and the mandrel being removed subsequent to this operation.
One of the features of the instant invention is . .,:: .
illustrated in ~ig. 5 and this is the application of cable to hose structures rather than the utilization of monofil-ament wires which are more conventionally used.

.. . . .
Since cables are normally fashioned through a linear system of dies and twisted into a cable, if the ~ ~
cable is thereafter wound about a small radius, the cable -~ -strands will not be properly arranged (twisted) to assume equal portion of the outward radial load. Thus, in some cases when the cable is wrapped about a small radius, the load distribution is completely unsatisfactory and the theoretical burst strength which should be obtained with the cable reinforcing is not achieved. In general, in .

-: - : : : ,:, ~C~54535 reference to Fig. 5, a special winding technique is illus-trated schematically wherein a cable winding deck 70 is employed having a plurality of separately tensioned monofilament supply reels 71. These monofilament strands are supplied from deck 70 through a guiding die 72, located adjacent to the surface of the core structure which has an aperture 73 through which these wires pass. In general, the winding deck and die revolve about the outer surface of the hose structure and because the winding deck 70 rotates about its central apertures through which the individual cable strands 74 pass they are wound into a twisted forma-tion as the spiral convolutions are wrapped. Since each of the wire supply spools are separately tensioned, the individual strands in the resulting cable applied to the circular surface of the hose structure have substantially the same tension even though they are wrapped about a ~ -~
relatively small radius and thus the load carrying capacity of the resulting cable approaches its theoretical value.
It is important to recognize the twist of the filaments forming the cable can occur prior to the application thereof to the hose so long as the filaments are sufficiently tensioned so they move to the proper load carrying relation-ship in the spiral winding as it is formed. Thus, there is a slight relative axial movement of the filaments during the winding of the reinforcing. In addition, the twisting can occur within an elastomer extrusion head so that the individual filaments are coated with an uncured elastomer.
While this arrangement is illustrated schematically, by reference to Figs. 7 and 8 the technique of applying cable can be readily understood according to the above description.

. .

1~54535 In general, the wire reinforcing elements used to manufacture the reinforced hose are relatively stiff brass-plated high strength wire having diameters in the range of .005 to .030 inches. Where the cable reinforcing is used, the cable is merely made up of wires of this kind which are twisted into the cable structure.
More generally, when the reinforcing plys are wound, the winding head or die 51 trains a plurality of stiff resilient reinforcing elements onto the surface of 10 the core so that they are wrapped in a parallel side-by-side :
relationship, the angle of which is determined by the rotational speed of the deck and the axial advance speed of the mandrel through the aperture and the winding deck. In general, it is desired that the angle of wrap with reference to the longitudinal axis of the mandrel be maintained in the neighborhood of 54 44' which is the mathematical, theoret-ical desirable angle for the wire reinforcing employing two such plys.
~ ormally to achieve high quality hose the speed of the winding deck and the speed of axial advance are closely controlled to achieve an angle of approximately 54 44' rel-ative to the hose axis. Further, by the use of a soft bond stock and the fabric surface on the core structure formed according to this invention, the diameter of the cylindrical winding surface ean be more closely maintained thereby allowing greater precision in the control of the angle of ~--the reinforcing which is applied to the core structure and also its subsequent plys.
In general, when a core structure such as the kind described herein is employed and the theoretical angle is ~' .
- . .. . : .. - -. ;. , . . . : . .

~5~535 closely approximated when the reinforcing elements are applied, the resulting hose structure has less of a problem with "snaking" i.e. hose movement occurring when pressure changes occur within the hose. The latter occurs when high pressure hydraulic hose is pressurized since the variations in the reinforcing plys move to neutralize the forces in the hose and as this occurs, movement is introduced into the hose.
Such movement of the reinforcing plys at higher pressures are undesirable since it can result a shearing action which can cause pinholing in the hose structure leading to leakage.
The invention in its broader aspects is not limited to the specific method and apparatus shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A reinforced hose comprising a cylindrical core composed of a helical winding of a laminate having solely a single elastomer layer and a fabric layer, the elastomer layer forming the inner layer of the core; a layer of bonding elastomer on the outer, fabric surface of the core; a first cylindrical ply of a plurality of substantially inextensible reinforcing elements wound around the layer of bonding elas-tomer with sufficient tension on each of the elements to penetrate at least partially the bonding elastomer layer in a series of side-by-side helical convolutions to form a first cylindrical reinforcing ply having a wall thickness substan-tially equal to the diameter of the elements; a second cylin-drical ply of substantially inextensible reinforcing elements wound around the first cylindrical reinforcing ply in a series of helical convolutions to form a second cylindrical rein-forcing ply having a wall thickness substantially equal to the diameter of the elements, the first and second cylin-drical plies being arranged so that their respective helical convolutions are of opposite hand; and a cylindrical elas-tomer jacket encircling the resulting reinforced core, the jacket and reinforced core being vulcanized in an integral unit.

2. The wire reinforced hose defined in claim 1 wherein the fabric surface layer is formed with an open mesh fabric.

3. The wire reinforced hose defined in claim 1 wherein the fabric surface is formed with a plurality of randomly disposed short fabric fibers disposed on the elastomer layer of the laminate.

4. The wire reinforced hose defined in claim 1 wherein the fabric surface layer of the laminate has a thickness from .006 inches to .020 inches and the elastomer layer has a thickness from .015 inches to .050 inches.

5. The wire reinforced hose defined in claim 1 wherein the bond stock has a thickness from .005 inches to .020 inches and a layer of bond stock is placed between the cylindrical reinforcing plies.

6. The wire reinforced hose defined in claim 1 wherein the reinforcing elements of the several rein-forcing plies are composed of multiple wire strands which are twisted into a cable as said elements are wound, each of said strands being applied with an independent tension whereby said strands are oriented and disposed within the cable forming the circular reinforcing ply to equally share the radial loads on said hose.

7. The wire reinforced hose defined in claim 6 wherein the multiple wire strands of each cable have an individual diameter from .005 inches to .015 inches.

8. The wire reinforced hose defined in claim 6 wherein elastomer is extruded around the several strands of each cable to provide elastomer insulation between said strands.

9. The wire reinforced hose defined in claim 1 wherein two additional reinforcing plies are present in the reinforced core structure, alternating plies having the same spiral wrap.

10. The wire reinforced hose defined in claim 1 wherein the cylindrical core has the laminate wound therein in a spiral overlapping relationship to form said at least two concentric fabric layers with the resulting core having an outer fabric surface.

11. The wire reinforced hose defined in claim 1 wherein the angle of said spiral wrap in each of said reinforcing plies is approximately 54° 44'.

12. A cable reinforced hose comprising:
a cylindrical hollow core having fabric disposed therein to increase its hardness;
a first cylindrical reinforcing ply of a plurality of inextensible cable elements wound on said core in a series of side-by-side spiral convolutions to form said first cylindrical ply having a wall thickness approximately equal to the diameter of each of said cables, said cables having a plurality of wire strands therein which are separately tensioned as each cable element is wound on said core whereby each strand and each cable element is disposed and oreinted in its ply to better resist outward radial loading thereon;

a second cylindrical reinforcing ply of a plurality of inextensible cable elements wound on said first cylin-drical reinforcing ply in a series of side-by-side spiral convolutions to form said second cylindrical ply having a wall thickness approximately equal to the diameter of each of said cables having a plurality of wire strands which are separately tensioned as each cable is wound whereby each strand in each cable is disposed and oriented in its ply to better resist outward radial loading thereon, said spiral convolution of said second cylindrical reinforcing ply being angularly disposed to the spiral convolutions in said first cylindrical reinforcing ply;and, a cylindrical outer elastomer jacket encircling the resulting cable reinforced core, said elastomer jacket and said cable reinforced core being vulcanized as a integral unit.

13. The cable reinforced hose defined in claim 12 wherein the core is formed with a laminate having layers of elastomer and fabric therein.

14. The cable reinforced hose defined in claim 13 wherein the laminate is wrapped to form a core with at least two concentric layers of fabric in the wall of said core.

15. The cable reinforced hose defined in claim 12 wherein the individual wire strands making up the cables are monfilament steel wires having a diameter from .005 inches to .015 inches.

16. A method of making wire reinforced hose comprising the steps of:
forming a laminate having a fabric layer and an elastomer layer on the outer surfaces of said laminate;
wrapping said laminate on a mandrel with the elastomer layer thereagainst to form a hollow cylindrical core with an outer fabric surface;
covering the outer fabric surface of the resulting core with a layer of bonding elastomer having compatible bonding characteristics with wire reinforcement;
winding under tension on said bonding elastomer a plurality of inextensible reinforcing elements in side-by-side spiral convolutions to form a first cylindrical reinforcing ply having a ply thickness equal to the diameter of said reinforcing elements;
winding under tension on said first cylindrical reinforcing ply a plurality of inextensible reinforcing elements in side-by-side spiral convolutions which angularly cross said spiral convolutions of said first ply to form a second cylindrical reinforcing ply;
encircling the resulting reinforced core structure with elastomer to form an outer jacket of said hose; and vulcanizing the elastomers and reinforcing elements and core as an integral unit.

17. The method as defined in claim 16 which includes the step of wrapping the hose with shrink tape prior to the vulcanizing step whereby the elastomers are densified during said latter step.

18. The method defined in claim 16 wherein the process includes the additional step of adding bonding elastomer on the first cylindrical reinforcing ply before the second cylindrical reinforcing ply is formed thereon.

19. The processes defined in claim 16 wherein the reinforcing elements are wound in their respective plies at an angle of approximately 54° 44' relative to the longitudinal axis of the hose.

20. The method as defined in claim 16 wherein the reinforcing elements are monofilament steel wires having a diameter from .005 inches to .030 inches.

21. The method as defined in claim 16 wherein the laminate is formed by calendaring a fabric layer onto an elastomer layer, said fabric layer having a thickness from .006 inches to .020 inches, and said elastomer layer having a thickness from .015 inches to .050 inches.

22. The method as defined in claim 21 wherein the fabric layer is fabricated by calendaring short randomly oriented fibers onto the surface of the elastomer layer.

23. The method as defined in claim 16 wherein the step of wrapping the laminate on the mandrel is accomplished by winding a tape formed from the laminate in a spiral overlapping relationship to achieve at least two concentric fabric layers in the wall of the hollow core structure.

24. The method as defined in claim 16 wherein the reinforcing elements are cable, each cable composed of multiple strands of wire, each of said strands of wire being separately tensioned when the cable is wound on the core structure with cable being formed during the winding process, thereby being operable to cause the individual strands in each cable element to be disposed in its reinforcing ply in a position to better oppose outward radial loadings on the hose structure.

25. A method of forming cable reinforced hose comprising:
forming a hollow elastomer core on a mandrel;
winding a plurality of cable reinforcing elements on said elastomer core in side-by-side spiral convolutions to form a first cylindrical reinforcing ply, each of said cable elements being composed of multiple strands of wire, each strand of which is separately tensioned as its cable element is wound on the core structure;
winding a plurality of cable reinforcing elements on said first cylindrical reinforcing ply in side-by-side spriral convolutions to form a second cylindrical reinforcing ply, said spiral convolutions of said second reinforcing ply angularly crossing those of said first reinforcing ply, each of said cable elements in said second reinforcing ply being composed of multiple strands of wire, each strand of which is separately tensioned as its cable element is wound;
encircling the built-up cable reinforced hose structure with jacket elastomer to form its outer covering;
and subsequently vulcanizing said core, said reinforcing elements and said jacket elastomer into an integral unit to form cable reinforced hose.

26. The method defined in claim 25 wherein bonding elastomer is employed to cover the elastomer core before the first cylindrical reinforcing ply is wound thereon and a layer of bonding elastomer is applied over said first cylindrical reinforcing ply prior to the time the second reinforcing ply is wound thereon.

27. The method as defined in claim 25 wherein the cable reinforcing elements are wound at an angle of approximately 54° 44' in reference to the hose axis in both the first and second cylindrical reinforcing plies.