US 4,928,509 A · Method for manufacturing a pipe with projections

Abstract

A method for forming projections on the periphery of a pipe in order to provide branch pipes, such as a manifold for automobiles, is characterized in that the branch pipes are formed by a bulging process to have a predetermined thickness without thinning. A first embodiment includes the step of indenting a pipe member by press work or the like, at locations close to the position of a projection which is to be formed, in a preliminary deforming process. The deformed pipe member is then placed in a bulge mold having a recess or space, with the pipe member being positioned so that the indentations in the pipe member lie adjacent the recess in the bulge mold. Pressurized fluid is then introduced into the interior of the pipe member to bulge the wall of the pipe member into the recess in the bulge mold. A second embodiment employs a bulge mold having fixed recesses or spaces and variable recesses or spaces for forming a plurality of projections. The second embodiment includes the step of bulging the pipe material into the fixed spaces while the variable spaces are occupied by detachable members, and the step of removing the detachable members from the mold and then bulging the pipe member again.

Claims9

Dependent claims

A method for manufacturing a pipe with a projection at a predetermined position, comprising the steps of:

(a) deforming a pipe to provide a recess close to the predetermined position, the deformation of the pipe altering an inner dimension of the pipe;
(b) placing the pipe in a bulge mold;
and
(c) forcing pressurized fluid into the pipe to bulge the pipe at the predetermined position so as to form the projection.

1 more element

Dependencies are inferred from the claim text.

Method for manufacturing a pipe with projections

Life of this patent

Method for manufacturing a pipe with projections

Life of this patent

Abstract

Claims9