A gear rack for a longwall mining machine characterized in having a width permitting the arms which carry the cutter drums of the mining machine to move to lower positions relative to a face conveyor such that low seams of coal may be mined. The rack comprises a plate extending along the face conveyor and has driving pin extensions which extend from one face of the plate to engage a driving gear or gears on the mining machine.

A spray nozzle for use in the elbow interconnecting a coke oven ascension pipe and a main, characterized in having frusto-conical nozzle orifices which generate sprays which completely cover the elbow cross section only when they reach the transition between the elbow and the coke oven main.

A process is provided for producing electroluminescent powders for use in information display panels of the type in which a monoparticle layer of electroluminescent powder is embedded in a high dielectric constant resin between two electrodes. The powders are zinc sulfide powders coactivated with aluminum and capable of emitting white light, as well as light of various colors. In the production of these powders they are treated to form an impermeable inorganic surface coating on the powder parti...

A motor control system, particularly adapted for use with a battery-operated atmospheric hazard sampling pump, which can vary motor speed over a range of 50:1 with the use of a voltage controlled pulse width modulator. The system includes a back EMF circuit which develops a voltage, proportional to motor speed, which is compared with a speed reference signal to develop an error signal for the pulse width modulator. Automatic shutdown of the motor occurs for controlled periods when a blocked pump...

Steering apparatus for a reversible vehicle of the type adapted to travel on a guideway having at least one guide means extending parallel to the desired course of the vehicle, and wherein the vehicle includes front and rear guideaxle means adapted to follow the guide means together with front and rear wheel assemblies each having a pair of steerable wheels interconnected by tie rod means. The invention resides in the provision of a novel gear and linkage mechanism interconnecting respective whe...

An apparatus for granulation of precipitation products, comprising a liquid-filled reaction chamber including a granulation chamber which receives aqueous streams of compounds which precipitate to form granules. The granulation chamber has an open upper edge connected to the narrow edge of a conical surface. The upper open edge of the conical surface merges with an apron which is spaced inwardly from the inner periphery of the reaction chamber. Conduit means conduct granules downwardly from the ...

Thermal energy is converted into rotational energy by using the expansion of a fluid medium to propel a plurality of pistons within at least one continuous, closed-loop passageway mounted on a rotatable platform. In at least one region of the passageway, the pistons must move inwardly against centrifugal force as the platform rotates. In at least one other region of the passageway, the pistons are moved outwardly under the influence of centrifugal force. Means are provided for imparting force to...

A lightweight solar cell array for space vehicles powered by solar electric propulsion. The array incorporates a plurality of hinged solar cell units which can be folded for stowage and thereafter extended into a planar configuration. Light is directed onto the solar cell array by a flexible reflector assembly which is carried below the array. The reflector assembly preferably comprises sheets of flexible material stowed on rolls whereby the sheets can be pulled from the rolls into extended posi...

An artificial forearm and hand having a fully-articulated wrist motion. The invention provides an integrated digitally-controlled remote manipulator device capable of reproducing all of the major motions of the human forearm, wrist and hand in a cmpact in-line package. This motion is accomplished without the requirement for feedback thereby making the invention ideally suited to digital computer control. The packaging of the device permits it to be sealed, meaning that it can be used as a remote...

A system for charging dust and the like particles entrained in a gas stream and which are to be electrostatically precipitated. An emitter electrode is disposed in the gas stream for producing ions of one polarity which charge particles in the gas stream. These ions of one polarity and the charged particles are attracted to a surface on which at least a portion of the charged particles collect. The invention resides in the use of a second emitter electrode for producing ions of the opposite pola...