Method and apparatus for producing bypass grooves

An apparatus for producing multiple linear grooves on the inner wall of cylindrical tubes comprising:

• a cage member having an internal passage extending through its length, said passage centrally aligned with the cylindrical axis of said cage member;
• a cage sleeve having an axially aligned passage, said cage sleeve co-extensively connected to said cage member thereby creating a cage assembly having a continuous internal passage therein;
• a mandrel shank axially and slideably disposed within said passage of said cage assembly;
• a tapered mandrel tip co-extensively connected to said mandrel shank to create a mandrel assembly, said mandrel tip axially and slideably disposed exclusively within a central passage of said cage sleeve;
• a plurality of retaining ports through said cage sleeve, said retaining ports aligned within the same circumferential plane which is perpendicular to the cylindrical axis of said cage sleeve;
• a plurality of roller elements individaully positioned within said retaining ports of said cage sleeve, said rolling elements rollingly engaging said tapered mandrel tip disposed within said cage sleeve;
• means for retaining said roller elements within said retaining ports to maintain resting contact of said roller elements within said tapered mandrel tip;
• actuation means for producing nonrotational linear motion of said cage assembly and said mandrel assembly;
• and
• control means for selectively controlling said actuation means to produce variable groove profiles during operation of said tool.

A method of producing grooves on the inner walls of a cylindrical tube, said method comprising the steps of:

• positioning said cylindrical tube;
• providing a groove forming tool comprising a cylindrical cage sleeve and cage member co-extensively connected to define a cage assembly having a central axial passage extending therethrough, a mandrel shank co-extensively connected to a tapered mandrel tip defining a mandrel assembly slideably disposed with said central passage of said cage assembly, at least one retaining port extending through said cage sleeve, a roller element disposed within said retaining port and rollingly engaging a tapered surface of said mandrel tip, retaining means for retaining said roller element in said retaining port, and first and second actuation means operatively connected independently to said cage member and said mandrel shank respectively for generating linear nonrotational motion of said cage assembly and said mandrel assembly;
• actuating said first actuation means to introduce said cage assembly with said mandrel assembly disposed therein into an inner diameter of said cylindrical tube along a common cylindrical axis;
• actuating said second actuation means for radially expanding said roller member into rolling contact engagement with said inner diameter of said cylindrical tube to generate a groove impression;
• actuating said first actuation means upon engagement of said roller element and said inner tube diameter to provide linear movement of said cage assembly to generate a groove impression of a given length so as to define a groove such that forward actuation of said cage assembly introduces the entry end of said tool into the inner diameter of said cylindrical tube, forward linear actuation of said mandrel assembly produces radial expansion of said spherical balls engaging said conically tapered mandrel tip to create pressing contact of said spherical balls with said cylindrical tube inner walls thereby generating said multiple groove impressions.

An apparatus for automatically producing multiple grooves on the inner wall of cylindrical tubes comprising:

• a cylindrical cage member having an internal passage extending through its length, said passage centrally aligned with the cylindrical axis of said cage member;
• a cylindrical cage sleeve having an axially aligned passage, said cage sleeve co-extensively connected to said cage member thereby defining a cage assembly having a continuous internal passage therein;
• a mandrel shank axially and slideably disposed within said passage of said cage assembly;
• a conically tapered mandrel tip co-extensively connected to said mandrel shank to create a mandrel assembly, said mandrel tip axially and slideably disposed exclusively within the central passage of said cage sleeve;
• a plurality of retaining ports through said cage sleeve, said retaining ports aligned within the same circumferential plane which is perpendicular to the cylindrical axis of said cage sleeve, said retaining ports being equally angularly spaced around circumference of said cage sleeve;
• a plurality of spherical balls, said spherical balls individaully positioned within said retaining ports of said cage sleeve, thereby rollingly engaging said conically tapered mandrel tip disposed within said cage sleeve;
• a cylindrical split spring sleeve mounted on the outer diameter of said cage sleeve, said split spring sleeve having circumferentially spaced holes identical in angular orientation with the circumferential spacing of said retaining ports, said spring sleeve retaining said spherical balls within said retaining ports to maintain rolling contact of said spherical balls with said conically tapered mandrel tip;
• reciprocating actuation devices, said actuation devices operatively connected individaully to said mandrel assembly and said cage assembly thereby generating linear nonrotational motion of said assemblies;
• and
• means for controlling the linear motion generated by said activation devices;
• whereby forward actuation of said cage assembly introduces the entry end of said tool into the inner diameter of said cylindrical tube, forward linear actuation of said mandrel assembly produces radial expansion of said spherical balls restingly following said concially tapered mandrel tip which creates pressing contact of said spherical balls into said cylindrical tube inner walls thereby generating said multiple groove impressions.