The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 08, 1977
Filed:
Mar. 07, 1975
Sixten Harald Lejdegard, Ramnas, SW;
Bulten-Kanthal Aktiebolag, , SW;
Abstract
An internal spline drive formation for screws is provided wherein the spline drive formation comprises a plurality of circumferentially alternating equiangularly spaced grooves and splines, said splines being defined in part by part-cylindrical surfaces and said grooves being defined in part by surfaces which, when viewed in plan, are arcuate to form a parabola-like line in that the radius of curvature is very small at the regions of intersection between the spline side surfaces and the groove bottom and increases gradually towards the center line of the groove bottoms. Also disclosed is a screw driving tool the bit end of which comprises an external spline drive formation having a surface which, when viewed in plan, comprises an outer cylinder having sunk therein a plurality of equiangularly spaced grooves, defined in part by re-entrant part-cylindrical surfaces, the regions of intersection between said grooves and said outer cylinder being sharp as contrasted to curved.