Abstract:
The present invention is directed to a rubber hose wherein the reinforcing layers are formed from ebonite rubber. The ebonite rubber has a thickness sufficient to provide the desired reinforcing characteristics to the hose. The hose may be formed with integral hose flanges wherein the hose flanges are also formed from ebonite rubber.

Description:
FIELD OF THE INVENTION 
     The present invention is directed towards a hose. Specifically, the hose is reinforced with ebonite to provide the hose with the desired physical characteristics. 
     BACKGROUND OF THE INVENTION 
     Ebonite is a known rubber compound containing a high sulfur content, typically compounded with 30 to 50% by weight sulfur, having a high Shore A hardness. Ebonite compounds have been used in tank linings for chemical products and in other applications where hardness and impermeability are desired. For example, U.S. Pat. No. 4,469,729 discloses that in the past, for flexible articles such as belts, hoses, and diaphragms, the inner surface of the article was harden by ebonite formation. This was done to improve wear resistance, reduce friction, and provide for a barrier effect. 
     U.S. Pat. No. 5,222,770 discloses a high-pressure hydraulic hose. The multi-layered hose has an inner layer, an intermediate insulation layer, and an outer layer. Between the layers are several conductive layers. The inner, intermediate, and outer layers may be rubber or ebonite. 
     While ebonite has been used as an alternative to rubber layers in various articles, the presently disclosed invention is directed towards previously unappreciated benefits of ebonite in an article. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a light weight, inexpensive hose and a method of forming such a hose. 
     The inventive hose is comprised of at least a cover layer, an innermost layer, and at least one intermediate reinforcing layer. The reinforcing layer is formed from an ebonite rubber. 
     In one aspect of the invention, the ebonite rubber comprising the at least one reinforcing layer has a Shore D hardness in the range of 75 to 100, preferably 90 to 100. 
     In another aspect of the invention, the ebonite rubber comprising the at least one reinforcing layer has a sulfur content of 10 to 50% by weight. 
     In another aspect of the invention, the hose is formed with an integral flange formed at at least one end of the hose. The hose is formed with the integral flange being comprised of a central disc of ebonite rubber. 
     Also disclosed in a method of forming a hose comprising an inner layer, at least one intermediate reinforcing layer, and an outer layer. The method is comprised of forming an inner layer, applying a reinforcing layer of uncured ebonite rubber over the inner layer, and applying a cover layer to form a hose assembly. The hose assembly is cured to form the hose. 
     In another aspect of the disclosed method of forming a hose, the ebonite rubber is applied until it reaches the thickness required to achieve a desired strength in the cured hose. 
     In another aspect of the disclosed method of forming a hose, an ebonite disc is applied to at least one end of the hose assembly prior to curing the hose assembly to form an integral flange on the hose. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described by way of example and with reference to the accompanying drawings in which: 
     FIG. 1 is a hose formed in accordance with the present invention; 
     FIG. 2 is another embodiment of the present invention; 
     FIG. 3 is hose with an integral flange; and 
     FIG. 4 illustrates the assembly method for forming the hose with an integral flange. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a hose  10 . The hose  10  has the simplest construction that is in accordance with the present invention. The hose  10  has an inner layer  12 , an intermediate reinforcing layer  14 , and a cover layer  16 . The inner layer  12  and the cover layer  16  are formed of conventional hose materials, including thermoplastic and thermoelastic materials. The material selection will vary depending upon the application and desired properties of the hose. The inner layer  12  is selected to be resistant to the material to be conveyed by the hose  10 . The intermediate reinforcing layer  14 , instead of being the conventional textile or metallic reinforcement layer, is an ebonite layer. The reinforcing ebonite layer  14  is built up to a thickness to accomplish the desired strengthening of the hose to replace the various conventional reinforcement layers typically found in a hose. In forming the ebonite reinforced hose, after the inner layer  12  is formed, either by extrusion about a mandrel or form or by winding unvulcanized rubber about a mandrel, the ebonite rubber is extruded over the uncured inner layer or sheets of uncured ebonite rubber is wound over the uncured inner layer until the desired thickness to obtain the required strength in the cured hose is achieved. 
     The ebonite rubber has a base rubber of any sulfur vulcanizable rubber, and a sulfur content of 10 to 50% by weight, preferably 10 to 20% by weight. The ebonite rubber has a Shore D hardness of 75 to 100, preferably 90 to 100 Shore D. 
     The hose may be formed with more than the three specified layers. The hose may also have an intermediate rubber layer, see FIG.  2 . The hose  20  has an inner layer  22 , a reinforcing layer  24 , an intermediate rubber layer  26 , a second reinforcing layer  28 , and a cover layer  30 . 
     A hose may be formed in any lay-up construction known to those in the art. For example, the inner layer  12  or  22  may be several layers, including a barrier layer, a friction layer, and an adhesive layer. Whatever construction is chosen for the hose, the main reinforcing layer of the hose is formed from an ebonite rubber material. 
     The hoses  10 ,  20  formed in accordance with the present invention are most suitable for use as suction and discharge hoses, since such hoses do not require a high degree of flexibility. Such hoses  10 ,  20  are used for transporting ore slurry, water, chemical products, and other such flowable materials. It is desired that suction and discharge hoses be highly durable since the hose is subject to extreme working conditions, including being dragged and pulled along rough surfaces. Because an operator may carry the hose around, it is also desired to reduce the weight of the hose. The use of the ebonite in the hose provides the hose with the desired strength needed for such a hose, while reducing the weight and the cost of the hose. 
     To further reduce the weight of the discharge hose, the hose may be formed such that the conventional iron flanges attached to the ends of the hose are eliminated, as disclosed in a further embodiment of the present invention. 
     FIG. 3 illustrates a hose  30  formed with an integral flange  32 . The body  34  of the hose  30  is formed in accordance with the simplest hose construction, as disclosed previously. The hose  30  has an inner layer  36 , an intermediate reinforcing layer  38 , and a cover layer  40 . A flange  32  is formed at at least one end of the hose  30 . 
     FIG. 4 illustrates a hose being formed with integral flanges  32  at both ends of the hose  30 ; however, if desired, the flange  32  may be formed at only one end of the hose  30 . The desired inner layer  36  is first applied to a mandrel (not illustrated). Over the inner layer  36 , the necessary layers of ebonite  38  are applied until the specified thickness to achieve the desired reinforcement of the hose  30  is achieved. The cover layer  40  is then applied to form a hose assembly. Nylon tape (not illustrated) is then applied over the hose assembly. 
     Two-part flanges  42  are placed near the ends of the hose assembly. The ends  44  of the cover layer  40  are turned up over the two-part flanges  42 . The ends  46  of the ebonite layers  38  are then also turned up, adjacent the ends  44  of the cover layer  40 . Discs of ebonite  48  are placed against the turn up ends  44 ; each ebonite disc  48  preferably has the same thickness as the conventional steel flange that the disc  48  is replacing. The ends  50  of the inner layer  36  are turned up adjacent the discs  48 . Curing flanges  52  are then placed over the turned up ends  44 ,  46 ,  50  and discs  48 . The final hose assembly is cured, after which the two-part flanges  42 , the cure flanges  52 , and the nylon tape are removed. Following curing the ebonite disc  48  and the turned up ends  44 ,  46 ,  50  of the hose layers  36 ,  38 ,  40  are transformed into the integrally formed rigid flanges  32 . 
     The above formed method is one method of constructing the integral flanges  32 . In an alternative method, instead of turning up the ends of the various hose layers  36 ,  38 ,  40  to sandwich the ebonite disc  48 , layers of material corresponding to the material of each layer may instead be applied to the ends of the hose assembly. After the hose assembly is prepared on a mandrel, the two-part flanges  42  are placed at the ends of the hose assembly. If it is desired to form only one flange  32 , than a two-part flange  42  is located at only one end of the hose assembly. 
     Rubber layers of the same material as the cover layer  40  are applied over the flanges  42 . Discs of ebonite are applied. Ebonite rubber layers corresponding to the layer  38  may be applied to the ebonite discs. If no such additional ebonite layers are applied, than the ebonite disc has the same composition as the layer  38 . Rubber layers corresponding in material to the material of the inner layer  36  are placed over either the ebonite discs or the additional ebonite layers, encapsulating the ebonite between the two different non-ebonite rubber layers. Curing flanges  50  are than placed over the built up layers and the final hose assembly is cured. 
     The flange  32  may be provided with passageways  54  for bolts or other mechanical mechanism to be inserted into the flange for securing the hose  30  to other hoses, couplings, or fittings when the hose  30  is in use. These passageways  54  are formed when the hose  30  is cured. 
     By forming the inventive hose with integral ebonite flanges, the conventional hose constructed from tire cord plies, steel wires, and metal flanges is replaced by a light weight, rigid, and less expensive hose. 
     Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is therefore to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.