Injection molding nozzle heater clamp
AssigneeRosemount Aerospace Inc.
InventorJohn P. Beck
Life of this patent
Estimating the term…
Abstract
A clamp for clamping heater assemblies onto cylindrical bodies such as injection molding nozzles that require heating. The clamp includes a mandrel that slips over the nozzle, and has a heater wound on the exterior. The mandrel has a longitudinal slit that will permit the bore of the mandrel to be reduced in size when a lateral width of the slit is reduced. The mandrel carries outwardly facing cam surfaces, and an overlying sleeve has inwardly facing cam surfaces which mate, and upon relative longitudinal movement, the cam surfaces cause the lateral width of the slit to reduce and clamp the mandrel onto the nozzle. The clamping can be effected by differential movement due to differences in thermal expansion of the mandrel and the sleeve, or by mechanical movement of the sleeve relative to the mandrel to obtain the cam action.
Claims15
A heater assembly for use on a cylindrical member, comprising:
- a mandrel having a mandrel longitudinal length and a bore of sufficient size to receive a cylindrical member to be heated and having an outer surface;
- a heater carried on the outer surface of the mandrel and coiled around the mandrel along the length thereof, said mandrel having a cam surface on a first end thereof that tapers relative to a longitudinal axis of the mandrel, the mandrel having at least one longitudinal slit having a width that permits the bore to reduce in size when the slit reduces in width;
- and
- a sleeve that surrounds and is spaced from a substantial portion of the outer surface of the mandrel to form a space for the heater, the sleeve also being spaced outwardly from the heater, said sleeve having a complementary end cam surface on a first end thereof for engaging the at least one cam surface on the mandrel, one of the sleeve and mandrel having a higher coefficient of thermal expansion than the other of the sleeve and mandrel so that upon heating the sleeve and mandrel with the heater to a temperature above room temperature a differential longitudinal movement between the sleeve and the mandrel occurs, a second end of the sleeve and a second end of the mandrel being configured to restrain longitudinal movement induced by differential thermal expansion between the sleeve and the mandrel, the engaging cam surfaces causing forces when the sleeve and the mandrel have relative differential longitudinal movement to reduce the slit width to thereby clamp the mandrel onto a cylindrical member on which the mandrel is mounted substantially solely under cam generated forces.
A clamp for a cylindrical body forming an injection molding nozzle comprising;
- a mandrel that has a bore of size to slidably fit over the cylindrical body, said mandrel having a substantially cylindrical outer surface portion and slit extending longitudinally on one portion thereof to form a gap which can reduce in width to reduce the size of the bore in the mandrel to clamp onto the cylindrical body;
- a first cam surface on the mandrel that tapers in radial directions and longitudinally and is at a first end of and joins the substantially cylindrical outer surface portion;
- a cylindrical sleeve mounted over said mandrel, said cylindrical sleeve overlying and being spaced from the mandrel cylindrical outer surface and having a second mating cam surface at a first end to mate with said first cam surface of the mandrel, the mandrel having a third cam surface at a second end of the mandrel spaced in a longitudinal direction from the first cam surface, the second end of the sleeve having a fourth cam surface engaging the third cam surface, the second and fourth cam surfaces overlying and surrounding the first and third cam surfaces so that upon relative longitudinal movement between the mandrel and the retainer, the second and fourth cam surfaces cause slidable engagement of the facing first and third cam surfaces to reduce the width of the gap and clamp the mandrel onto the cylindrical body, the sleeve and mandrel being in contact substantially only at the respective engaging cam surfaces.
A heater assembly for use on a cylindrical member to be heated, comprising:
- a mandrel having a bore of sufficient size to slide over a cylindrical member to be heated;
- a heater wound on the mandrel around an exterior surface portion thereof, said mandrel having spaced apart flanges at opposite ends of the exterior surface portion between which the heater is wound, and said flanges extending radially outward farther than the heater and having cam surfaces formed at outer edges thereof spaced outwardly from the exterior surface portion that face outwardly and taper relative to a longitudinal axis of the mandrel;
- a sleeve that slides over the mandrel, and substantially surrounds and is spaced from the heater on the mandrel, said sleeve having complementary cam surfaces for engaging the cam surfaces on the flanges of the mandrel when the sleeve and the mandrel have relative differential longitudinal movement, said mandrel having at least one slit from the exterior to the bore ant extending longitudinally therein, so that upon longitudinal differential movement between the sleeve and the mandrel, the cam surfaces on the sleeve ace on the cam surfaces of the mandrel such that the bore of the mandrel reduces in diameter as the slit closes to tend to clamp onto a cylindrical member over which the mandrel is slid.
Dependencies are inferred from the claim text.