Joint for coupling tubes

• US 6,022,053 A
• Filed: 03/26/1998
• Issued: 02/08/2000
• Est. Priority Date: 03/27/1997
• Status: Expired due to Term

• Current Assignee: Flowell Corporation
• Original Assignee: Flowell Corporation
• Inventors: Hukuda, Shin-Ichi
• Primary Examiner(s): Nicholson, Eric K.
• Application Number:
  US09/048,185
• Time in Patent Office: 684 Days
• Field of Search: 285/331, 285/354, 285/246, 285/247, 285/423
• US Class Current: 285/331
• CPC Class Codes: F16L 19/0283 and having a bell-mouthed shape
• CPC Class Codes: F16L 47/041 the plastic pipe end being flared either before or during the making of the connection

Abstract

A joint for coupling tubes forming a large diameter portion near one end of a fluorocarbon resin tube and forming a fastened portion by clamping at a crimp portion of the large diameter portion with a cap nut includes of a main body of rigid resin joint having a cylindrical portion formed a ring-shaped groove and cut a bevel at its inner wall end and a hard cap nut having a inner shoulder formed an acute-angle hook. The major portion of the large diameter portion of the fluorocarbon resin tube is inserted into the ring-shaped groove. A tube clamp portion as a hermetic portion is formed to press hard a tube crimp portion against the inner wall end of the cylindrical portion with the inner shoulder of the hard cap nut by tightening the hard cap nut on an external thread of the outer wall of the cylindrical portion.

Claims

1. A joint for coupling tubes of a fluorocarbon resin, having a normal diameter portion, a large diameter portion near one end, and a crimp portion between said normal diameter portion and said large diameter portion prior to engagement with said joint, and forming a fastened portion by clamping said crimp portion with a cap nut consisting of a main body of rigid resin having a cylindrical portion, having a ring-shaped groove and a bevel at an inner wall end of said cylindrical portion;

and a hard cap nut having an inner shoulder with a hook that forms an acute angle relative to the tube wall, wherein a major portion of the large diameter portion of the fluorocarbon resin tube is inserted into the ring-shaped groove; and

wherein a tube clamp portion, as a hermetic portion presses said tube crimp portion against the inner wall end of the cylindrical portion with the inner shoulder of the hard cap nut by tightening the hard cap nut on an external thread of the outer wall of the cylindrical portion.

2. A joint for coupling tubes by fitting one end of a tube, said tube having an expanded end, prior to engagement with said joint, around an end portion of a main body of the joint inserted into a tapped hole of a cap nut and supporting the end of the tube with the cap nut screwed on the main body,

said cap nut having an inner wall formed in the tapped hole orthogonal to the center line of the tapped hole, an internal thread formed on the inner surface of the tapped hole and an insertion opening cut through the inner wall along the center line for inserting the tube,

said main body of the joint having a cylindrical portion, formed at the end of the main body which is inserted into the tapped hole of the cap nut where the tube inserted through the insertion opening of the cap nut fits around the main body and keeps the expanded end of said tube;

an external thread formed on a base side, from which the cylindrical portion is elongated, for screwing into the cap nut and a through hole cut through the main body along the main body center line having approximately the same diameter as the inner diameter of the tube and having a bevel at an end of the cylindrical portion, the bevel being formed from the inside of the through hole to the outside

a minor diameter of the internal thread and the diameter of the inner surface of the cap nut being nearly equal or slightly larger than the outer diameter of the tube fitted around the cylindrical portion.

3. A joint for coupling tubes by fitting one end of a tube, said tube having an expanded end, prior to engagement with said joint, around an end portion of a main body of the joint inserted into a tapped hole of a cap nut and supporting the end of the tube with the cap nut screwed on the main body,

said cap nut having an inner wall formed in the tapped hole orthogonal to the center line of the tapped hole and having an acute-angle hook sloped towards a point at the center line in the tapped hole, an internal thread formed on the inner surface of the tapped hole and an insertion opening cut through the inner wall along the center line for inserting the tube,

said main body of the joint having a cylindrical portion, formed at the end of the main body, which is inserted into the tapped hole of the cap nut where the tube inserted through the insertion opening of the cap nut fits around the main body and keeps the expanded end of said tube;

an external thread formed on a base side, from which the cylindrical portion is elongated, for screwing into the cap nut and a through hole cut through the main body along the main body center line having approximately the same diameter as the inner diameter of the tube and having a bevel at an end of the cylindrical portion, the bevel being formed from the inside of the through hole to the outside of the hole,

a minor diameter of the internal thread and the diameter of the inner surface of the cap nut being equal or nearly equal to the outer diameter of the tube fitted around the cylindrical portion.