Claims
- 1. A process for making a wire wrapped, preformed, semirigid, high vacuum or pressure polytetrafluoroethylene plastic hose, said hose having spiral convoluted inside and outside surfaces, said process comprising the steps of:
- (a) drawing out a length of reinforcing steel spring wire stock;
- (b) looping said wire stock around a forming device in order to form said wire into a continuous spiral coil;
- (c) pulling said looped spiral wire from said forming device and through a guide for maintaining the spiral formed shape of said wire;
- (d) taking up said wire in a valley of a preformed spiral convolution on the outside surface of said semirigid hose whereby said reinforcing wire around the outside of said hose increases its resistance to internal pressure or vacuum; and
- (e) embedding said wire in the valley be deforming under heat and pressure said convolution to capture said wire and reinforce said hose and maintain its internal diameter in the presence of either pressure or vacuum.
- 2. The process of claim 1 wherein said spiral convolution is formed on the outside surface of said hose and step (d) comprises the further step of rotating said hose to wind said wire about it, and the winding of said hose furnishes the motive power for pulling said wire from said stock.
- 3. The process of claim 2 wherein the diameter of said formed spiral coil is such that the wire wrapping snaps into the valley of said spiral convolution.
- 4. The process of claim 2 wherein said plastic tube has a wall height to outside diameter ratio in the range of approximately 8.8 to 19.3.
- 5. The process of claim 2 wherein said plastic tube has a wall height and said wire has a diameter with a ratio of wire diameter to wall ratio in the order of 3.1 to 6.2.
Parent Case Info
This is a continuation of application Ser. No. 885,389, filed Mar. 10, 1978 now U.S. Pat. No. 4,196,031.
US Referenced Citations (10)
Continuations (1)
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Number |
Date |
Country |
Parent |
885389 |
Mar 1978 |
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