Flexible drive shaft

A flexible drive shaft for portable tools, comprising in combination:

• a) a flexible elongated housing comprising a sleeve, a first end cap and a second end cap affixed one each to opposite end portions of said sleeve, each said end cap being configured with a central opening to form with said sleeve an elongated structure with endmost interior accessibility for enabling intermediate connection to be made therethrough between a tool and a prime mover,
• c) a plurality of torque transmission elements disposed in said housing in free, unconnected, tightly abutting, end-to-end axially nested arrangement, said elements being similarly configured with a polygonal cross-sectional shank end portion at one axial extremity and a polygonal cross-sectional socket end portion at the other axial extremity, wherein one said element cross-sectional shank end portion operable nests in a polygonal cross-sectional socket end portion of a next adjacent said element, with each said element having limited freedom of universal movement from axial alignment with a next adjacent said element, the endmost of said elements being configured one with a distal end portion configured for making operable connection to a prime mover and a second with a distal end portion configured for making operable connection for driving a tool,
• d) resilient means disposed within said housing forcibly biasing all said elements into constant tightly abutting, nested disposition.