The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 31, 1989
Filed:
Oct. 16, 1987
Armin Dommer, 7257 Ditzingen 1, DE;
Dieter Dommer, 7257 Ditzingen 1, DE;
Other;
Abstract
The invention is a method and apparatus for butt-welding two adjoining plastic tubular members which are held in axially adjustable mountings and which are joined together under axial pressure after heating in the area of their juncture by means of electric heating elements. Welding without formation of an interior bead is made possible with the invention by inserting into the plastic tubular members, prior to heating, a bolster which bridges the juncture and fits flush against the inside curvature of the plastic tubular members, and by applying in the area of the juncture shell-shaped heating elements to the outside of the plastic tubular members to heat the abutting ends of the plastic tubular members from the outside.