Apparatus and dies for forming peelable tube assemblies

• US 5,840,151 A
• Filed: 11/13/1996
• Issued: 11/24/1998
• Est. Priority Date: 02/04/1993
• Status: Expired due to Term

• Current Assignee: Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Munsch, John M.
• Primary Examiner(s): AFTERGUT, JEFFRY H
• Application Number:
  US08/747,776
• Time in Patent Office: 741 Days
• Field of Search: 156/380.6, 156/379.8, 156/380.2, 219/769, 219/765
• US Class Current: 156/380.2
• CPC Class Codes: A61B 2017/00526 Methods of manufacturing
• CPC Class Codes: B29C 53/32 Coiling B29C53/56 takes precedence
• CPC Class Codes: B29C 65/02 by heating, with or without pressure
• CPC Class Codes: B29C 65/04 Dielectric heating, e.g. high-frequency welding , i.e. radio frequency welding of plastic materials having dielectric properties, e.g. PVC
• CPC Class Codes: B29C 65/4895 Solvent bonding, i.e. the surfaces of the parts to be joined being treated with solvents, swelling or softening agents, without adhesives
• CPC Class Codes: B29C 65/7802 Positioning the parts to be joined, e.g. aligning, indexing or centring
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/5227 for forming multi-tubular articles by longitudinally joining elementary tubular articles wall-to-wall (e.g. joining the wall of a first tubular article to the wall of a second tubular article) or for forming multilayer tubular articles
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/8322 Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29K 2027/06 PVC, i.e. polyvinylchloride
• CPC Class Codes: B29L 2023/005 Hoses, i.e. flexible
• CPC Class Codes: B29L 2031/601 Multi-tubular articles, i.e. composed of a plurality of tubes hollow-walled B29L2024/00

Abstract

An apparatus for forming coiled tubular assemblies is provided. The apparatus includes a pair of dies formed from a radio frequency (RF) conducting material. The dies each have contoured leading surfaces with these surfaces having grooves with lands between adjacent grooves. The lands of the dies cooperate to form web forming chambers when the pair of dies are moved together in their operative position. In the operative position, the tubes are captured in the aligned grooves with portions of the tubes being squeezed or extruded into the web forming chamber. Application of RF energy to the dies causes the tube portions in the chambers to plasticize and form webs between the coils of the tubes with a predetermined configuration substantially the same as that of the web forming chambers. Both radially coiled and axially coiled tube assemblies are contemplated by the invention. In addition, an easy-to-separate or peel tubular assembly is formed with the above apparatus.

Claims

1. In an apparatus for forming tube assemblies of plastic tubular members which can be peeled to separate the tubular members from one another, a set of radio frequency dies placed about the tubular members to connect spaced portions of adjacent tubular members together, the die set comprising:

a pair of dies having respective leading surfaces which can be moved between a tube-receiving first position and an operative second position wherein in the first position the die surfaces are spaced at a first predetermined distance from each other and in the second position they are spaced at a second predetermined distance less than the first distance for forming the tube assembly, the dies being formed from an RF energy conducting material;

a plurality of cooperating grooves formed in the leading surfaces of the dies with grooves of the dies aligned with each other to cooperate to define die bores in the operative position, the die bores being sized to engage and radially compress the tubular members without occluding the flow passages of the tubes; and

a land between pairs of adjacent grooves of the leading surfaces of the dies with corresponding lands on the die surfaces facing each other to define flow chambers for portions of the tubular members near the flow chambers which are plasticized upon application of RF energy to the dies for forming connecting webs of plastic between adjacent tubular members in the flow chambers when the dies are in their operative position.

2. The die set of claim 1 wherein the die bores are smaller than the diameter of the tubular members.

3. The die set of claim 1 wherein the dies are formed of a brass material.

4. The die set of claim 1 wherein the tubular members are coiled radially about an axis with the outer tubular member coil of the coiled tubular members having the largest radius from the axis and the inner tubular member coil having the smallest radius from the axis;

the plurality of cooperating grooves includes an outer groove and an inner groove; and

the grooves include arcuate portions each having a radius substantially equal to the radius of the corresponding coil of the coiled tubular members with the radius of the arcuate portions progressively decreasing from the outer groove to the inner groove.

5. The die set of claim 4 wherein the arcuate portions of each groove includes an outer arcuate side and an inner arcuate side each having a radius with the radius of the inner side and the radius of the outer side of one of the grooves each being different from the radius of the respective inner and outer sides of another adjacent groove by the diameter of the tubular members and the width of the land between the grooves.

6. The die set of claim 1 wherein the lands have an arcuate shape having a radius with the radius of the arcuate lands progressively decreasing from an outer land to an inner land for forming arcuate shaped connecting webs between the coiled tubular members.

7. The die set of claim 1 wherein the dies have spaced ends and a groove edge closest to each end is beveled to prevent RF energy from plasticizing tube portions proximate the beveled edges.