Back to results
US 4,225,981 AGranted
Endo prothesis with a metal-ceramic union
AssigneeRosenthal Technik AG
InventorAnton Zeibig
Life of this patent
Estimating the term…
Abstract
In a bone joint endoprosthesis, the spigot of the metal shank is externally threaded to mate with a thread inside the ceramic head of the prosthesis; the thread on the spigot has greater depth in the radial direction, with flat sides, and the depth of the thread in the head is more shallow.
Claims17
A bone joint endoprosthesis comprising:
- a metal shaft having a spigot defined thereon;
- said spigot having an external thread defined thereon;
- said external thread being comprised of a raised rib extending around said spigot;
- said external thread rib having a profile height, which is the radial height of said rib on said spigot, and having a profile width, which is the longitudinal length of said rib along said spigot;
- a ceramic head having an opening defined therein in which said externally threaded spigot is received;
- said opening being defined by a side wall which is internally threaded with an internal thread which is mated with said spigot external thread;
- said internal thread being comprised of a groove into said side wall in said opening and said external thread rib being received in said groove;
- and said internal thread having a profile height into said side wall which is less than said profile height of said external thread rib.
5 more elements
A method of making a bone joint endoprosthesis, comprising the steps of:
- forming a rib like external thread with flat, generally parallel side walls of the rib, and having a plurality of turns thereof on the exterior of a spigot of a metal shaft;
- forming a mating internal thread comprised of a groove having a plurality of turns in the side wall that defines an opening in a ceramic head;
- forming the profile height, which is the radial height of the external thread rib on the spigot between the side walls, of the external thread to have a greater radial height than the cooperating profile height of the groove of the internal thread in the opening of the ceramic head;
- inserting the spigot into the threaded opening of the ceramic head by matingly screw connecting the spigot into the ceramic head;
- prior to inserting the spigot into the opening in the ceramic head, heating the metal shaft to an elevated temperature.
2 more elements
Dependencies are inferred from the claim text.