Abstract: A floor anchor and leveler system for an electronic equipment rack has a leveler shaft welded or otherwise rigidly attached at the upper end to a perpendicular base plate. A leveler foot and jam nut threads onto the leveler shaft. A threaded bolt extends coaxially through the leveler shaft and engages a floor plate which is rigidly attached to the floor using anchor bolts or other means. The jam nut and leveler foot are loosely threaded onto the leveler shaft, sufficiently high to allow the caster to contact and roll on the floor. The rack is positioned on its casters until each of the floor anchor and leveler systems, which are each attached to an underside of the rack, is located and centered above its corresponding threaded floor plate anchor hole. After positioning the rack, a tie-down bolt is installed coaxially through each leveler shaft and loosely engages the threaded floor plate and anchor hole.

Abstract: High melting temperature Pb/Sn 95/5 solder balls are connected to copper pads on the bottom of a ceramic chip carrier substrate by low melting temperature eutectic Pb/Sn solder. The connection is made by quick reflow to prevent dissolving Pb into the eutectic solder and raising its melting temperature. Then the module is placed on a fiberglass-epoxy circuit board with the solder balls on eutectic Pb/Sn solder bumps on copper pads of the board. The structure is reflowed to simultaneously melt the solder on both sides of the balls to allow each ball to center between the carrier pad and circuit board pad to form a more symmetric joint. This process results in structure that are more reliable under high temperature cycling.

Abstract: A method and apparatus for minimizing escapement positioning error by matching the move sequence of a print carrier to the mechanical system dynamic characteristics without the use of a feedback sensor are described. A plurality of constant velocity signals are provided for driving the print carrier to the next print position. The sequential velocity signals comprise an acceleration velocity signal and a deceleration velocity signal, the duration of which are dependent upon the damped natural frequency of the print system. For long escapement moves, a slew velocity command is provided between the acceleration and deceleration velocity commands so as to maintain the velocity of the print carrier at the amplitude it had attained at the conclusion of the acceleration velocity signal. The relative amplitudes of the acceleration, slew and deceleration velocity signals are a function of the damping ratio of the printer system.