US 4,044,092 A · Groove molding method

Abstract

A method for molding, in a single integrated operation, a tubular part having an internal recess which may take the form of a groove extending completely around the inside of the part for receipt therein of an O-ring or the like. The method utilizes an apparatus which comprises a core assembly having a longitudinal axis, and base means movable along the axis and defining an annular outer mold surface for forming of the interior wall of the tubular part. The core assembly further includes a plurality of groove-forming segments carried on the base means adjacent to the annular surface and movable between first contracted positions and second expanded positions. In accordance with the method, when the segments are in the contracted positions they do not extend radially outwardly of the annular surface, and the segments may be withdrawn from the molded tubular part by movement along the longitudinal axis. The segments are movable, incident to movement of the annular surface into the mold cavity, to the radially expanded molding positions wherein they extend substantially radially outwardly from the annular surface. The segments are mechanically locked in the radially expanded positions during molding of the tubular part. After the part is molded, some of the groove-forming segments are moved radially inwardly to withdraw them from the molded groove. Then, these withdrawn segments move axially relative to the remaining segments and the latter segments themselves withdraw from the groove. The segments are configured and arranged so that some can move radially inwardly from the expanded positions. Thus, deep, circumferential grooves can be molded in a tubular part as part of the basic molding of the part, and without requiring a secondary operation.

Claims18

Dependent claims

A method for molding an annular groove internally in a tubular molded part, said method comprising:

a. providing a mold core assembly having an outer mold surface and a plurality of first mold segments forming a first group and a plurality of second mold segments forming a second group thereof circumferentially around and intermediate the ends of the mold core,
b. introducing said mold core assembly into a mold cavity,
c. molding a part in said cavity and radially expanding said first and second groups of segments to form a recess in the molded part,
d. moving the first group of segments radially inwardly until they are fully withdrawn from the recess,
e. initiating axial movement of the first group of segments relative to the second group of segments after being withdrawn from said recess,
f. moving the second group of segments radially inwardly until they are fully withdrawn from the recess, and which radial movement of the second group of segments starts approximately when or without substantial delay after said first group of segments starts said axial movement,
g. initiating axial movement of the second group of segments, and
h. removing the molded part from the cavity.

5 more elements

A method for molding a tubular part having an annular internal recess, said method comprising the steps of:

a. providing a mold cavity;
b. providing a movable core assembly in said cavity, which core assembly includes a first group and a second group of recess-forming means which combine to define in their radially expanded condition structure configured to form an annular internal recess in the part to be molded;
c. molding a part in the mold cavity;
d. effecting radially inward movement of the recess-forming means to thereby withdraw said means from the molded recess, said effected radially inward movement being achieved by:
1. first moving the first group of recess-forming means radially inwardly until they are fully withdrawn from the recess,
2. then effecting axial movement of the first group of recess-forming means after being withdrawn from the recess,
3. moving the second group of recess-forming means radially inwardly until they are fully withdrawn from the recess, and which radial movement of the second recess-forming means starts approximately when or without substantial delay after said first recess-forming means start said axial movement,
4. thereafter initiating axial movement of the second recess-forming means,
e. moving the core assembly to withdraw it from the molded part;
and
f. removing the molded part from the mold cavity.

8 more elements

Dependencies are inferred from the claim text.

Groove molding method

Life of this patent

Groove molding method

Life of this patent

Abstract

Claims18