Abstract: A down hole blow out preventer which can be installed at the lower end of a drill string as close as possible to the drill bit and which can isolate an unexpected producing zone in a bore hole from the rest of the hole by closing off the drill string at its lower end and closing off the annulus between the drill string and the wall of the bore hole by means of an inflatable packer. The packer can be operated when a predetermined pressure difference exists between the annulus and the mud column inside the tool.

Abstract: A laminated winding for electric machines comprises a cylinder formed of a roll of conductive strip-like material isolate on one side and having a roll wall. The cylinder includes axial slots across the roll wall alternatively starting from the one roll end and from the other roll end and extending nearly up to the opposite roll end leaving a circumferential portion and so as to form a wave winding. The laminated winding further comprises electrical terminals for supplying an electrical current through the wave winding. Preferably, the axial roll portion between the slots and the circumferential roll portions are of equal width. A first one of the windings may be arranged as a rotor and a second one of the windings may be arranged as a stator of a rotating electric machine.

Abstract: A laminated coil which may be used as a winding in electrical machinery is formed by multiple layers of thin electrically conductive material, each having an insulating layer on one side and being shaped in a specialized pattern. The patterns each form a winding and are shaped such that current flow therethrough generates a magnetic pole at only three of four cross-sectional sides. The laminated coil is formed of layers of these patterns arranged to provide a magnetic pole at all four sides.