Mandrel for the production of reinforced plastic tubing

Claim 2

A MANDREL FOR THE PRODUCTION OF TUBING, COMPRISING: A HOLLOW CORE INCLUDING A PLURALITY OF PARALLEL ELONGATED MEMBERS SPACED EQUIDISTANTLY FROM EACH OTHER ABOUT THE CIRCUMFERENCE OF A CIRCLE AND SLIDEABLY MOUNTED ON A COMMON HEADPLATE, AN ENDLESS STRIP WOUND HELICALLY AROUND SAID CORE IN A DIRECTION AWAY FROM THE HEADPLATE AND EXTENDING BACK THROUGH THE INTERIOR OF THE CORE, SUCCESSIVE CONVOLUTIONS OF THE HELICALLY WOUND STRIP FORMING A CONTINUOUS SURFACE ON WHICH THE TUBING IS FORMED, MEANS FOR ADVANCING SAID ENDLESS STRIP ALONG A HELICAL PATH AWAY FROM THE HEADPLATE, AND ADJUSTMENT MEANS FOR SIMULTANEOUSLY MOVING SAID ELONGATED MEMBERS RADIALLY OF THE CIRCLE EQUAL DISTANCES WHEN A CHANGE IN DIAMETER OF SAID CORE IS DESIRED.

Claim 3

A mandrel as recited in claim 1, wherein said adjustment means comprises a rotatable drive mounted centrally of said headplate, a plurality of rotatable shafts extending radially of the circle each having means connected at one end and engaging said rotatable drive, at least a portion of each shaft being threaded, and means associated with each of said elongated members in threaded engagement with a corresponding one of said shafts whereby the member is moved radially of the circle along the shaft when the shaft rotates.

Claim 4

A mandrel for the production of tubing, comprising: a hollow core including a plurality of parallel spaced rollers disposed equidistantly from each other about the circumference of a circle and supported by a headplate; an endless strip wound helically around said core in a direction away from the headplate and extending back through the interior of the core, successive convolutions of the helically wound strip forming a continuous cylindrical surface on which the tubing is formed; drive means for rotating at least one of said rollers to advance said endless strip about said core; and adjustment means mounted on said headplate and connected to each of said rollers, the adjustment means being effective to simultaneously move said rollers radially of the circle equal distances when a change in the diameter of said core is desired.

Claim 5

A mandrel for the production of tubing, comprising: a hollow core including a plurality of parallel spaced rollers disposed equidistantly from each other about the circumference of a circle and supported by a headplate; an endless strip wound helically around said core in a direction away from the headplate and extending back through the interior of the core, successive convolutions of the helically wound strip forming a continuous cylindrical surface on which the tubing is formed; drive means for rotating at least one of said rollers to advance said endless strip about said core; and adjustment means mounted on said headplate and connected to each of said rollers, the adjustment means being effective to simultaneously move said rollers radially of the circle equal distances when a change in the diameter of said core is desired.

Claim 6

A mandrel for the production of tubing, comprising: a hollow core including a plurality of parallel spaced rollers disposed equidistantly from each other about the circumference of a circle, each roller being rotatably mounted on a common headplate and movable along said headplate radially of the circle; an endless strip wound helically around said core in a direction away from the headplate and extending back through the interior of the core, successive convolutions of the helically wound strip forming a continuous cylindrical surface on which the tubing is formed; and a combination drive and diameter adjustment means mounted on said headplate and being selectively effective to produce either synchronous rotation of said rollers to advance said endless strip about said core or simultaneous movement of said rollers radially of the circle to change the diameter of the core.

Claim 7

A mandrel for the production of tubing, comprising: a hollow core including a plurality of parallel spaced rollers disposed equidistantly from each other about the circumference of a circle, each roller being rotatably mounted on a common headplate and movable along said headplate radially of the circle; an endless strip wound helically around said core in a direction away from the headplate and extending back through the interior of the core, successive convolutions of the helically wound strip forming a continuous cylindrical surface on which the tubing is formed; and a combination drive and diameter adjustment means mounted on said headplate and being selectively effective to produce either synchronous rotation of said rollers to advance said endless strip about said core or simultaneous movement of said rollers radially of the circle to change the diameter of the core.

Claim 8

A mandrel as recited in claim 4, wherein said combination drive and diameter adjustment means comprises a central rotatable drive, and a plurality of radially extending mechanical transmission members each connected at one end to said central drive and at some point along its length to one of said rollers in a manner to selectively effect either rotation of the roller or movement of the roller radially of the circle when said central drive is rotated.

Claim 9

A mandrel as recited in claim 5 wherein said combination drive and diameter adjustment means comprises a main gear mounted centrally of said headplate, a plurality of shafts, one for each of said rollers, mounted on said headplate and extending radially of the circle, at least a portion of each shaft being threaded, each shaft having a first gear connected to one end thereof and rotatably engaging said main gear, each shaft having a second gear spaced radially outwardly of the circle from the first gear and rotatably engaging a gear on a respective one of said rollers, the second gear being threaded to mate with the threaded part of the shaft, and means for selectively locking the second gear of each shaft relatively either to the shaft in a manner such that it will rotate with the shaft and thereby rotate the respective roller, or to the respective roller in a manner such that it does not rotate with the shaft but moves longitudinally of the shaft when the shaft is rotated, whereby said rollers are simultaneously moved along said headplate radially of the circle to effect a change in the diameter of the core.

Claim 10

A mandrel as recited in claim 6 wherein said locking means for the second gear of each shaft is a key pivotably mounted on the second gear and adpated to engage either a slot in the shaft when rotation of the respective roller is desired or a slot in a bearing housing for the second gear when adjustment of the roller radially of the headplate is desired, the bearing housing and the roller being mounted on a baseplate movable radially of the headplate.