Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-12-02
2001-11-20
Johnstone, Adrienne C. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C138S122000, C156S143000, C156S149000, C156S206000, C156S209000
Reexamination Certificate
active
06319350
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to the manufacture of hoses and more particularly to the manufacture of hoses in need of enhanced flexibility along with abrasion and chemical resistance.
The hose goes back to antiquity. It is fundamental to the operation of almost all machines and forms the linchpin upon which many technological advances depend. Improvement in basic hoses have allowed advancements in: aerial refueling; breathing in outer-space; solar heating collectors; ship-to-ship refueling; chemically and biologically resistant delivery systems; and deep sea diving.
In many applications, there is a significant need for a hose which has a highly durable outer coating to resist damage, wear and chemical degradation during handling. Unfortunately, the vast majority of durable materials which can be used in this context are stiff which promotes kinking and early failure. When a hose is made of this type of material, often the hose becomes so rigid it resembles a pipe more than a hose.
While stiffness may be acceptable in small lengths and in certain applications, the need to coil the hose for storage, bend for attachment ease, or flex during usage without inflicting permanent damage, becomes more problematic.
In one common method to improve the flexibility of such a hose, current technology uses a cure wrap placed over the uncured hose and a rope is tightly wound around the cure wrap. During the curing process, the rope's natural tautness and shrinkage, causes corrugations in the outside of the hose. While this does serve to improve the flexibility of the hose, it falls short of achieving all of the benefits sought.
It is clear that there is a need for a production process which will enhance hose flexibility, improve abrasion resistance, and prevent other surface and chemical damage, while employing a wider range of desirable surface materials.
SUMMARY OF THE INVENTION
The present invention creates a method of producing a hose in which a relatively inelastic material, such as ultra-high molecular weight polyethylene, is wrapped around an uncured hose.
Those of ordinary skill in the art readily recognize a variety of compounds and structures which can be used to make the uncured hose. The preferred layering is:
an inner layer of ultra-high molecular weight polyethylene;
Layers of twine and wire, when necessary; and,
Layers of Ethylene Propylene Diene Monomer (“EPDM”) rubber.
Over this uncured hose, a layer of relatively inelastic material is placed. The ideal material in this context is a layer of ultra-high molecular weight polyethylene (UHMwPE). It has been found that UHMwPE is ideal in this situation since it withstands a great deal of abuse without cracking or degrading, while resisting a wide range of chemicals. Those of ordinary skill in the art recognize other materials which will serve in this function.
A rope is then wrapped about this combination with a cure wrap encircling the entire assembly. Note, in the preferred embodiment, the rope is placed in direct contact with the UHMwPE.
The hose is then vulcanized (cured). The cure temperature and the dwell time is dictated by the materials used, and is well known to those of ordinary skill in the art.
During the curing process, the cure wrap presses the high shrinkage rope against the inelastic material forcing the underlying EPDM rubber to be displaced. Corrugations are formed in the inelastic material without any significant decrease of the thickness of the inelastic material.
Once fully cured, the wrap and the rope are removed leaving a hose which has been covered by inelastic material (i.e. URMwPE) with significant valleys formed therein. These valleys allow the resulting hose to have significantly improved flexibility. Although, the valleys extend deeper than the thickness of the outer UHMwPE layer, it is the underlying EPDM rubber which has been displaced and not the URMwPE material. The thickness of the URMwPE remains essentially uniform throughout the formed hose.
The valleys where the rope was embedded into the hose provide for an “elastic” affect allowing the resulting hose to have a highly protective outer coating with significantly improved flexibility compared to a hose made with an inelastic cover material such as UHMwPE without corrugations.
The invention, together with various embodiments thereof, will be more fully explained by the accompanying drawings and the following description.
REFERENCES:
patent: 3155757 (1964-11-01), Kramer et al.
patent: 5145628 (1992-09-01), Karg et al.
patent: 740732 (1955-11-01), None
Johnstone Adrienne C.
Mark E. Ogram P.C.
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