Abstract: A loop current detector for detecting current flowing in a pair of telephone wires comprises:A. a saturable reactor having first, second and third windings, the first and second windings adapted to be connected in a loop circuit to pass DC current,B. resistance connected with the third winding to form therewith a voltage divider, and an oscillator having an AC output connected with the divider, characterized in that the AC voltage drop across the third winding is relatively high when no DC current flows through said loop circuit, and said drop is relatively low when DC current flows through said circuit, andC.

Abstract: An apparatus adapted for drilling earth formations, earth structures or the like essentially embodies an outer tubular means, hollow drill bit means, hammer assembly mechanism, and a rupturable interconnection means. The outer means is rotatable and axially movable having a drilling end insertable within the earth. Connected adjacent the drilling end is the hollow drill bit means which is conjointly rotatable with the outer means. Such outer drill bit means has an anvil impact shoulder formed on the interior surface thereof. The inner drill bit means is located within the outer member and is arranged, in a preferred embodiment, to be conjointly rotatable therewith. A percussion shoulder is integrally formed on the inner drill bit means and is arranged to selectively impact the anvil impact shoulder.

Abstract: Nonmetallic-sheathed cable is insulated and jacketed with expanded polyvinyl chloride comprising 8-24%, by volume, of gas.

Abstract: Continuous, uninterrupted paying of paper tape into a cable-making machine is made possible at high speed by an accumulating chamber for a folded supply of the tape. A pair of pinch rolls, one of which oscillates around the other, directs the paper to form uniform folds.

Abstract: The method of recovering copper by cementation using copper-iron materials as part of the cementation scrap, the copper and iron in said materials being substantially physically inseparable.