Joint structure for branch connectors in common rails

A joint structure for a branch connector in a common rail, comprising:

• a main pipe rail having a circumferential wall with inner and outer circumferential surfaces generated about an axis, said inner circumferential surface defining a conduit therein, a plurality of through holes formed transversely through the circumferential wall at an axial spacing, each of said through holes having a circumferential face, an outwardly flared pressure receiving seat formed on portions of the circumferential face adjacent the outer circumferential surface of said circumferential wall of said main pipe rail;
• a branch connector having a conduit to communicate with the conduit of said main pipe rail, the branch connector having an end, an enlarged joint head formed at the end thereof and forming a shoulder facing away from said end and a tapered pressure seat disposed in abutment against the pressure receiving seat of said main pipe rail;
• a nut surrounding portions of said branch connector, said nut having an array of threads and having a portion for pressing the shoulder of said joint head;
• and
• a sleeve nipple having a cylindrically generated base end surface extending through an arc of no more than 180.degree. and disposed in face-to-face engagement with portions of said outer circumferential surface of said main pipe rail surrounding and spaced from said pressure receiving seat, outer portions of said sleeve nipple at said base end surface being jointed to said outer circumferential surface of said main pipe rail, said sleeve nipple including a bore extending therethrough in alignment with said pressure receiving seat, said sleeve nipple further having a threaded face concentric with said bore so that said pressure seat of said branch connector is engaged against the pressure receiving seat of said main pipe rail by tightening the threads of the nut with the threaded face of said sleeve nipple.