Self-reinforced plastic hose and method for molding same

• US 3,872,893 A
• Filed: 02/07/1974
• Issued: 03/25/1975
• Est. Priority Date: 05/01/1972
• Status: Expired due to Term

• Current Assignee: Robert E. Roberts
• Original Assignee: Robert E. Roberts
• Inventors: Roberts, Robert E.
• Primary Examiner(s): Silbaugh, Jan H.
• Application Number:
  US05/440,458
• Time in Patent Office: 411 Days
• Field of Search: 264/89,90,92,93,94,98,99,173,209,286,DIG.52,290,151,314,322 138/121,122,140,153,173,129 156/205-209 161/119 425/387,387B,326,326B,388
• US Class Current: 138/121
• CPC Class Codes: B29C 48/0016 using a plurality of extrusion dies
• CPC Class Codes: B29C 48/0017 combined with blow-moulding or thermoforming
• CPC Class Codes: B29C 48/09 Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels
• CPC Class Codes: B29C 48/13 Articles with a cross-section varying in the longitudinal direction, e.g. corrugated pipes
• CPC Class Codes: B29C 48/21 the layers being joined at their surfaces
• CPC Class Codes: B29C 49/0021 using moulds or mould parts movable in a closed path, e.g. mounted on movable endless supports
• CPC Class Codes: B29C 49/22 using multilayered preforms or parisons
• CPC Class Codes: B29K 2021/00 Use of unspecified rubbers as moulding material
• CPC Class Codes: B29K 2023/22 Copolymers of isobutene, e.g. butyl rubber
• CPC Class Codes: B29K 2027/06 PVC, i.e. polyvinylchloride
• CPC Class Codes: B29L 2023/18 Pleated or corrugated hoses
• CPC Class Codes: B29L 2031/7732 Helical springs B29L2031/774
• CPC Class Codes: Y10S 264/52 Processes of making corrugated tubes for gas mask

Abstract

The hose of the present invention comprises an all plastic multilayer hose having a reinforcement therein which is of a material which is flexible and stiff under normal working conditions and which has a flow temperature less than the flow temperature of the cover and liner layers and which forms spaced reinforcing elements incident to the manufacture of the hose. The present invention contemplates use of an apparatus and simplified method which permits the reinforced hose to be readily manufactured in predetermined lengths or continuously so as to provide a hose of indefinite lengths.

Claims

1. The method of making a self-reinforced corrugated hose of thermoformable elastomeric material without the necessity of incorporating non-elastomeric reinforcement materials comprising the steps of forming a tubular member by extruding an inner tubular layer consisting essentially of elastomeric material, extruding a tubular reinforcing layer consisting essentially of elastomeric material over said inner layer, and extruding a tubular cover layer consisting essentially of elastomeric material over said reinforcing layer, the material of the reinforcing layer having a flow temperature lower than the material of the inner layer and the cover layer, inserting said tubular member into a mold having a cavity provided with a corrugated wall, heating said tubular member to a molding temperature above the flow temperature of the reinforcing layer and lower than the flowtemperature of the inner layer and the cover layer, applying internal pressure to the tubular member to force the cover layer of the tubular member into conforming engagement with the corrugated mold wall to mold the exterior of the hose, said pressure being sufficient to cause portions of the flowable reinforcing layer to be displaced into the troughs in the cover layer produced by the corrugations of the mold, and to cause the cover layer and inner layer to engage and adhere together over the crests of the corrugations of the mold, and setting the hose as molded in a single mold operation, said reinforcing layer forming accurately and uniformly spaced resilient reinforcing portions conforming to the corrugations of the mold and disposed between said inner layer and said cover layer.

2. The method according to claim 1 in which said tubular member is formed by extruding said inner tubular layer, said tubular reinforcing layer and said tubular cover layer in a triple extruder.

3. The method according to claim 1 in which each of said layers consists essentially of a polyvinyl chloride elastomer.

4. The method according to claim 3 in which said molding temperature is about 370* F.

5. A continuous molding method according to claim 1 in which reinforced corrugated hose of continuous length is molded and subsequently cut into hoses having the desired lengths.

6. A self-reinforced, extruded, corrugated hose produced according to the method of claim 1.

7. A self-reinforced, extruded, corrugated hose produced according to the method of claim 2.