Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C61/00—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor
  • B29C61/02—Thermal shrinking
  • B29C61/025—Thermal shrinking for the production of hollow or tubular articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C61/00—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor
  • B29C61/04—Thermal expansion
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C61/00—Shaping by liberation of internal stresses; Making preforms having internal stresses; Apparatus therefor
  • B29C61/06—Making preforms having internal stresses, e.g. plastic memory
  • B29C61/08—Making preforms having internal stresses, e.g. plastic memory by stretching tubes

Definitions

• the present invention relates to a method of manufacturing a plastic tube.
• the method is primarily intended for manufacturing a flexible plastic tube which has a comparatively large collar and, for example, is suited for connecting a dish washing machine to a water pipe.
• the main object of the invention is to provide a simple method of manufacturing a plastic tube having at least one end with another outside and
• the method can generally be used for manufacturing plastic tubes having at least one section with a different outside and
• the connecting tube 10 shown on the drawing comprises a thinner section 10A and a thicker section 10B.
• the thin tube section 10A is at its free end provided with a connection means comprising a nut 11 and a packing ring 12.
• the nut and the packing ring abut from opposite sides a collar 13 provided on the tube section.
• the nut is provided with internal threads and is intended to be attached by screwing on the end of a connection tube 14 of a dish washing machine.
• the packing ring 12 will then be sealingly positioned between the collar 13 of the tube section 10A and the end of the connection tube 14.
• the thick tube section 10B is also at its free end provided with a connection means comprising a nut 15 and a packing ring 16.
• the nut and the packing ring abut from opposite sides a collar 17 provided on the tube section.
• the nut 15 is provided with internal threads and is intended to be attached by screwing on the end of a water pipe 18.
• the packing ring 16 will then be sealingly positioned between the collar 17 of the tube section 10B and the end of the water pipe 18.
• the plastic tube is at both ends provided with projecting portions 19 and 20, respectively, in front of the collars 13 and 17, respectively. These projecting portions 19,20 are intended for controlling and retaining the packing rings 12 and 16, respectively.
• the thick tube section 10B is bent to an angle of 90°. In the connecting tube shown on the drawing the section 10A has an outside diameter of 10 millimetres and the section 10B an outside diameter of 12 millimetres.
• the connecting tube shown on the drawing has been manufactured in the following way.
• a tube blank in the shape of a tube having an outside diameter of 12 millimetres has first been manufactured of a plastic material having memory characteristics, i. e. of a plastic material having the feature that it after a change of shape resumes the original shape when heated to a particular temperature, the so called crystalline melting-point.
• the tube blank has then been reduced by drawing, so that the outside diameter of the tube has become 10 millimetres.
• After the reduction the end sections of the tube have been heated to the crystalline melting-point. These sections have then resumed the original size, i. e. an outside diameter of 12 millimetres.
• a collar has then been formed in a conventional way at both ends of the tube. At one end only the portion intended for forming the collar has been heated, while at the other end a longer portion has been heated for forming the section 10B. This end section 10B has been bent to an angle of 90° to the shape shown on the drawing.
• the tube consists of cross-linked polyethylene that has a crystalline melting-point of about 130°C.
• the collar 17 provided at the free end of the thicker section 10B has a substantially larger diameter than the collar 13 provided at the free end of the thinner section 10A.
• This larger diameter can easily be provided, because the collar is formed on a tube having a larger outside diameter. Therefore, the collar can easily be made sufficiently large to fit the tube dimensions normally used for water pipes and required for connecting machines, so that leakageproof connections can be provided.
• the connecting tube 10 has a sufficient flexability due to the fact that the section 10A has a smaller outside diameter and, thus, is thinner. While only one example of the method according to the invention has been given above, it is evident that many variations and modifications are possible within the scope of the invention.
• the initially manufactured tube blank can for example be machined in such a way that the wall thickness is maintained or changed.
• the outside diameter of the tube can be reduced, maintained or increased.
• a section of a tube for example, can be provided with a thicker wall than the rest of the tube by heating to the crystalli- ne melting-point.
• This possibility can be utilized for manufacturing a tube having thicker walls at the tube ends, so that the ends of the tube easier can be provided with internal or external threads for connection purposes.
• any portion or section of the reduced tube can be heated to the crystalline melting-point, so that this portion or section resumes the original shape and thus obtains other dimensions than the rest of the tube.
• the inside diameter can be varied and several sections of the reduced tube can be heated to the crystalline melting- point.

Landscapes

• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Shaping Of Tube Ends By Bending Or Straightening (AREA)
• Rigid Pipes And Flexible Pipes (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20354472

Family Applications (1)

Country Status (4)

Cited By (9)

Citations (8)

• 1984
  • 1984-01-27 SE SE8400399A patent/SE451249B/sv not_active IP Right Cessation
• 1985
  • 1985-01-24 IT IT67064/85A patent/IT1182376B/it active
  • 1985-01-24 ES ES539806A patent/ES8606118A1/es not_active Expired
  • 1985-01-25 WO PCT/SE1985/000030 patent/WO1985003251A1/en not_active Application Discontinuation

Patent Citations (8)

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