Tapered worm

DETAILED DESCRIPTION The invention is claimed as follows: 1.
A worm and a gear meshing therewith, said worm comprising a first tapered rectilinear frustoconical portion at one end of said worm, a second tapered rectilinear frustoconical portion at the other end thereof immediately adjacent thereto and tapered oppositely to the first portion and fixed relative thereto, and a worm thread extending over both of said tapered portions, said oppositely tapered frustoconical portions being integral with each other and meeting one another with substantially no intervening portion, said worm thread having a common driving face thereon and extending across both of said rectilinear frustoconical portions, and said gear having a succession of teeth thereon having corresponding driven surfaces, a plurality of gear teeth driven faces being simultaneously drivingly engaged by said driving face of said worm thread on both of said frustoconical portions.
2.
A worm gear as set forth in claim 1 wherein said frustoconical portions each have an equal but opposite taper angle, the angle being such that gear teeth spaced by teeth are engaged by said worm thread driving face on both of said frustoconical portions 180 degrees out of phase.




Description:
BACKGROUND OF THE INVENTION Worm gearing is well known and is used in installations where a driving shaft and a driven shaft must be at right angles to one another.
The worm is of cylindrical outline in simplest form and has one or more thread turns or spiral teeth thereon.
A meshing worm gear has a plurality of apppropriately twisted teeth having tooth flank surfaces, generally of an involute curved shape, which are conjugate to the worm.
The instantaneous contact between a worm and a worm gear is at a rather limited area where the worm is tangent to the gear.
The area of contact is quite limited, generally being along a full ine on one tooth and a very short line on an adjacent tooth.
Consequently, only a limited amount of power can be transmitted between a worm and worm gear