Abstract: Disclosed is a crossover structure and method of fabricating such structure which contributes low capacitance to the circuit performance. The crossover utilizes a dielectric material which includes spheres of an insulating material in order to separate the conductors. In one aspect of the invention, a UV curable epoxy including hollow glass spheres is deposited on the crosspoint areas and the crossover connector deposited thereon. In another aspect of the invention, the crossover is formed with an air gap and the gap is subsequently filled with an encapsulating material including the spheres.

Abstract: A vertical thrust boring machine adapted to be positioned in the horizontal drift of a mine and to cut a tunnel extending upwardly from the drift so as to remove ore or other cuttings therefrom. The machine includes a rotary table for lifting a drill string which in turn supports the cutter head, and is characterized by drill stem sections having a spline connection on their lower ends, and a drive coupling ring associated with the rotary platform having a mating spline connection, so that when changing the length of the drill string the lowermost drill stem section can slide or float vertically relative to the rotary platform at the same time that it is being drivingly rotated.

Abstract: A drill stem especially adapted for use in a boring machine which drills upwardly, having pin and box joints on its respective ends, having a circumferential collar that is utilized for both vertical and rotational support of the drill stem section, and additionally having a spline connection on its lower end which is utilized for imparting rotating drive.

Abstract: Apparatus for aligning, supporting and stabilizing a drill string within a hole that is being drilled includes three elongated ski-like members which are disposed in circumferentially spaced positions about the drill string and in supporting engagement with the hole wall. Rotating bearing structures carried by the drill string are secured to the interior side of the ski-like members. The ski-like members are made in a number of longitudinal sections that are removably fastened together.According to the disclosed method, as the drill string is being extended and driven into the hole the ski-like members are assembled a section at a time and in such manner as not to interfere with the extension of the drill string.

Abstract: In order to install a heavy cutterhead upon a box hole boring machine, within the confined working space available in underground mining operations, the cutterhead is placed upon a wheeled dolly having a central opening through which the attachment stem of the cutterhead depends downwardly, a temporary bridge including a pair of rails is rested upon the top of the machine frame, and the dolly with cutterhead supported thereon is moved along the bridge to a position where the cutterhead can be attached to the machine. The vertical drive of the machine is then utilized to lift the cutterhead, and the dolly and temporary bridge are removed.

Abstract: A cutterhead adapted for drilling a hole upwardly in the earth, and to then be withdrawn downwardly through a casing which is inserted underneath the cutterhead, characterized by gauge cutters which are pivotally mounted on the cutterhead so that they will pivot upward and radially inward when the cutterhead is drawn into the casing, and also characterized by stabilizer rollers mounted on removable frames that can be detached.