Abstract: A direct current motor control system for generating current command signals to a unidirectional armature controller and a bidirectional field controller. A motor speed command is compared with the actual motor speed to generate a speed error signal. The system generates a current command signal from the average of the speed error signal wherein the current command signal is proportional to the square root of the desired motor torque. The absolute value of the current command signal is the input to the armature controller and the field controller receives the current command signal wherein the polarity of the signal determines the direction of current flow in the field winding for controlling the direction of rotation of the motor.

Abstract: A pipe saddle having a wear block adapted to engage a support surface with respect to which it is free to move. Glass fiber reinforced resin is employed as the outer surface of the saddle. A core is employed in the wear shoe to enable essentially uniform wall thicknesses of glass fiber reinforced resin to be maintained. Reduced frictional resistance to pipe motion relative to a supporting surface is achieved with a shoe insert having a low coefficient of friction relative to that surface on the bearing face of the wear block.

Abstract: A method and circuit for obtaining gray scale in gas discharge display panels which uses only one discharge site per resolution element, does not require extensive electronic memory and provides a continuous, broad intensity range. A maintain voltage is applied to all elements of the matrix display panel which has a magnitude somewhat less than the lower limit of the bistable region in which gas discharge panels are normally operated. Thus, a site cannot be turned "on" in the normal sense of initiating a sequence of discharges which continues indefinitely. However, the application of a trigger voltage can initiate a sequence of discharges which continues for a substantial number of cycles before dying out. The number of cycles for which the discharge sequence persists depends on the magnitude and duration of the addressing trigger voltage.

Abstract: Arrangement for and methods of operating electrically heated submerged throats between glass melter and final conditioning zones are disclosed which enable the pull rate of glass to be reduced while maintaining temperature control and to be stopped without freezing the molten glass in the throat. High rates of heat loss in the throat region are compensated for with a high voltage power supply to electrodes positioned for Joule effect heating of the glass in the throat. Thermal adjustment at maximum pull rates is enhanced by the use of cooled electrodes in the throat as heat extractors with no electrical energy supplied. Low or zero pull rates can be tolerated without throat freeze-up by connecting additional voltage sources in series with the supply to the throat electrode.

Abstract: There is disclosed a multiple gaseous discharge display/memory panel having an electrical memory and capable of producing a visual display, the panel being characterized by an ionizable gaseous medium in a gas chamber formed by a pair of opposed dielectric material charge storage members which are respectively backed by a series of parallel-like conductor (electrode) members, the conductor members behind each dielectric material member being transversely oriented with respect to the conductor members behind the opposing dielectric material member so as to define a plurality of discrete discharge volumes constituting a discharge unit, the dielectric having at least one electron emissive substance applied to the surface thereof in an amount sufficient to decrease the operating voltages of the panel. Typical electron emissive substances contemplated include Group IA elements, Group IA oxides, barium, GaAs, GaP, InAs, InSb, InP, NiO, CsF, CsI, AgOCs, and AuOCs.

Abstract: Electric power dissipation in a mass of molten glass is increased in a controlled manner where two or more power sources are each connected to at least two electrodes in the molten glass, by cross connecting the sources through a controller so that electrodes connected to each source and at proper potentials during a portion of each power signal period are connected together. The interconnection enables a substantial increase in voltage applied to localized regions of the molten glass without requiring higher voltage sources. Adjustment of the controller as the conductivity of the glass increases avoids runaway conditions. Interconnection of single and three phase power sources is disclosed.

Abstract: A method of anticipating electrode failure by monitoring the current, voltage and resistance between electrode pairs in a Joule effect heating system. A relatively rapid change in monitored resistance is an indication of an incipient failure. Alarm indicators, instruction print out, and/or process controls can be actuated in response to a given current voltage or resistance change. Plural electrode pairs are monitored by multiplexing to provide a repetitive cyclic scan of the parameters between pairs. Distortion of current and voltage values is minimized, where selective portions of regular power pulses are gated for control of heating, and complex waveforms result by employing true r.m.s. values of current and voltage developed in true r.m.s. to d.c. converters.

Abstract: A tachometer for generating a digital output signal representing velocity which is a stepped approximation to a 1/t velocity versus time curve where t is the time required to travel a fixed distance. High resolution is obtained by dividing the 1/t curve into octaves and an approximate straight line portion. A nonlinear counter counts a predetermined number of pulses during each octave as the time of the counting interval for succeeding octaves is doubled. Therefore, the counter total and the number of octaves completed after time t represents velocity. After completing eight octaves, the nonlinear counter counts at a predetermined frequency to generate a straight line approximation of the 1/t curve as it approaches zero velocity. The digital output can be converted to analog form by a digital-to-analog converter and operational amplifiers having an amplification factor determined by the number of octaves completed.

Abstract: Electrical erosion of refractory in a tank of a furnace for melting thermoplastic materials is reduced by orienting electrodes employed in Joule effect heating of the thermoplastic to limit the current density in the refractory. High electrical resistivity of certain thermoplastics tends to cause a flow of shunted current in relatively low electrical resistivity refractory of the furnace walls during Joule effect heating. Inter electrode spacing and electrode to furnace wall spacing is arranged according to the relative electrical parameters of the furnace system to achieve sufficient Joule effect heating of the thermoplastic without appreciable electrical corrosion. The effects of three phase power sources with various connections is disclosed.

Abstract: An orthodontic apparatus for use with a single straight arch wire in both the edgewise and the light-wire techniques to apply a continuous gentle pressure to teeth. One embodiment of the apparatus has a wire retaining bracket made of an elastomeric vinyl polymer which is banded to or molded integral with a band which is affixed to a tooth. The bracket has a pair of parallel upstanding wings which include a horizontal slot and retaining tips for retaining the arch wire. The horizontal slot has a liner formed of a substantially rigid material with the retaining tips formed on the upper and lower walls thereof. The wings have generally triangularly shaped tying tips for use with a ligature wire or elastic connector to apply pressure to a tooth. The tying wing tips also may have horizontal apertures therein for receiving a ligature wire. The bracket also has a vertical tubular aperture extending therethrough for retaining an attachment pin of a "C-clamp" appliance.

Abstract: Electric power dissipation in a mass of molten glass is increased where two or more power sources are each connected to at least two electrodes in the molten glass, by cross connecting the sources so that electrodes connected to each source and at proper potentials during a portion of each power signal period are connected together. The interconnection enables a substantial increase in voltage applied to localized regions of the molten glass without requiring higher voltage sources. Interconnection of single phase sources and two typical forms of interconnection of three phase power sources are disclosed.

Abstract: Heat softenable material, typically glass, is heated in a furnace from above its surface, as by fossil fuel burners, and below its surface, as by Joule effect heating by electrical current flowing between electrodes immersed in the melt where predetermined relationships of the amount of heat supplied from each source is automatically established. One form of coordinated control employs ratio control where the relationship of fossil fuel burner heat supplied is maintained in constant proportion to the Joule effect heat supplied. Melter temperature is a primary control for a combustion air supply. A combustion air-fossil fuel ratio controller proportionally controls Joule effect heat applied in one embodiment. In other embodiments the electrical controller provides the master signal to a combustion air control proportionate to the requisite change of heat input dictated, or the combustion air control issues a ratio signal to the electrical controller for proportional changes.

Abstract: A tube coupling having an arcuate grip surface which engages with and secures tubing with minimum scarring and distortion of the tubing. The grip surface is rotatable to successively present arcs of smaller radius to the tube whereby the gripping engagement tends to occur over a long line of contact. One embodiment employs a right-circular cylindrical cavity only slightly larger than the tube to be coupled for reception of the tube and a rotatable locking element mounted normal to the cavity and intersecting with the cavity to present a gripping surface to the cavity which upon rotation in a biased direction presents a groove defining in the cross-section of the cavity a succession of arcs of progressively smaller radius to the cavity and a tube therein until an arc conforms to and grippingly engages the tube as it bears against an opposing cavity wall. Various seal structures of elastomeric material are accommodated within the coupling body.

Abstract: A reversible control circuit for applying voltage pulses of opposite polarities to a load whereby the average current flowing in the load is a function of the maximum voltage at which the voltage pulses are applied and the duty cycle of the control circuit. The circuit may be utilized to control an electric motor field wherein the motor shunt field winding is connected across a four switch bridge circuit supplied from a direct current or rectified alternating current power source. Current flow in the field winding through a first pair of switches on opposite sides of the bridge can be reversed by opening the first pair of switches and closing the second pair of switches. If the switch pairs are alternately closed and opened in a rapid cyclic manner, the direction and magnitude of the current flow in the field winding can be controlled by varying the duty cycles of the switch pairs.

Abstract: An apparatus for intermittently applying compression to a portion of a patient's body enclosed in a therapeutic appliance. A timer is operated from a regulated pressurized fluid source to generate control signals to a valve which alternately inflates and deflates the appliance. The elements of the timer may be time delay valves, penumatic timing valves or fluidic elements which function to produce adjustable timing intervals for the control signals whereby the inflation and deflation intervals and the cycle time may be manually changed.

Abstract: An anti-skid system for a tandem axle vehicle including an improved vehicle suspension for opposing a selected portion of the braking torque which tends to unload the front axle during breaking to eliminate brake hop. The suspension cooperates with an anti-skid circuit to increase braking efficiency. In one embodiment, the anti-skid circuit senses a skid condition at the rear wheels on a per side basis and controls the braking of the wheels on that side in response thereto. In an alternate embodiment, the anti-skid circuit senses a skid condition at either the front or rear wheels on a per side basis and controls the braking of the wheels on that side in response thereto.

Abstract: A liner has a thin pliant tubular portion and a stiff base generally conforming to the bottom of a container into which it is inserted and capable of disposing the tubular portion against the walls of the container. The liner is disposed in intimate contact with the container upon the filling of the liner with a liquid material and the free open end of the liner is sealed against the container to maintain the liner in intimate contact therewith and prevent collapse of the liner upon agitation and dispensing of the liquid.

Abstract: A vehicle mounted mechanism for manipulating long load units such as pipe lengths which extend over a substantial portion of the load carrying length of the vehicle. The mechanism is stored within the width limit of the vehicle beneath its bed for over the road travel. It includes articulated linkages, and operating means attached to the side of the vehicle bed operable between the ground and an elevation substantially above the bed and over a substantial range transverse of the bed. An inner and outer boom support a load engaging assembly such as a cradle. The unit can be moved along the length of the vehicle bed while carrying a load and can operate adjacent wheels and other elements beneath the bed within the vehicle width limits. A power unit can be integrated with the loader and arranged for movement between a stored position and a position free of the region beneath the vehicle bed.

Abstract: An averaging circuit for producing average boat speed and average apparent wind speed which in cooperation with average apparent wind direction are utilized to determine the performance characteristics of sailing boats. Instantaneous values of the speed parameters are sampled at a predetermined frequency and a running average of N samples is generated by adding the most recent sample and discarding the oldest sample at periodic intervals. Display of the wind speed is delayed with respect to the display of boat speed to compensate for the effect of the inertia of the boat.

Abstract: A permanent magnet motor which generates mechanical output power by the repulsion forces between a movable permanent magnet and a fixed permanent magnet. A movable magnetic shield is interposed between the magnets when they are adjacent one another and then the shield is moved to expose the fixed magnet as the movable magnet passes by. A second fixed magnet can be added to increase the output power by attracting the movable magnet as it approaches. The movable magnetic shield is interposed between the movable magnet and the second fixed magnet when they are adjacent one another.