The output stability of an infrared thermocouple is improved by filtering the radiation received by the infrared thermocouple to pass only short wavelengths. The stability is further increased by providing a second infrared thermocouple having its input filtered to pass long wavelengths. The two outputs are combined to obtain an output signal which is substantially independent of emissivity. The linear range of an infrared detector through which its output closely follows that of a linear thermo...

A commutation control strategy for eliminating torque ripple and noise from a brushless motor which has a plurality of motor phases connected in a bridge, each phase having a top switching device provided between a phase winding and a positive voltage supply and a bottom switching device provided between the phase winding and a less positive voltage supply in which following commutations of the motor, when the current flowing in a first phase is decaying towards zero and the current in a second ...

Conventional vapor-compression refrigeration systems modified for greater efficiencies by installation of a liquid refrigerant level sensor in the drain line after the condenser, the sensor activating a valve in the high pressure vapor line in communication with the refrigerant receiver or reservoir, and the drain line being trapped to prevent vapor in the reservoir from backing up into the condenser.

A ballistic shield comprises a roll of ballistic blanket material having at one end thereof a device for attaching it at least temporarily to a structure so that the blanket may be unrolled to from a free hanging screen.

A two stage pump has coaxial first and second stage reciprocating pumps with the second stage piston reciprocably driven by the first stage piston. Multiple sets of first and second stage pumps are provided, and the second stage pistons can be returned by supercharge pressure, a loose connection between the first and second stage pistons, or a spring. An accumulator which is charged on a compression stroke and discharged on an intake stroke may also be provided in communication with a pumping ch...

A chassis for a loudspeaker assembly comprising a diaphragm and a chassis. The chassis is situated in front of the diaphragm of the loudspeaker. The chassis comprises a central member which is provided with an aperture so that it can be connected to the center pole of a magnet. Extending from the central member to an outer flange are a plurality of spokes or a perforated member which provide protection for the diaphragm.

A safe soldering device includes a retractable heat shield which can be moved between a first position in which the solder tip of the device is exposed for soldering operation and a second position in which the solder tip is covered by the heat shield. Preferably, the heat shield is biased towards the second position and may be locked in the first position for ease of use. When the soldering device is equipped with a vacuum system, the heat shield may serve to guide the flow of gases and heat fr...

An improved mechanism is provided for adjusting the clearance between the outer edges of impeller vanes of a centrifugal pump and the interior surface of an adjacent intake plate. The impeller having the vanes is mounted as an assembly to a back plate that can be secured to a casing or housing to which the intake plate is mounted. Threaded adjusters allow adjustment of the clearance between the impeller vanes and the intake plate. Additional modifications include a modified seal design to preven...

Improvements for use with table games include a first set of improvements which allow a player of a table game to more securely hold a paddle used in playing the table game. A second set of improvements provides a visual barrier which obscures a player's view of a playing surface of a game table, providing for more dynamic, challenging and entertaining play. A third set of improvements provides an elevated platform allowing players of significantly differing heights to comfortably, conveniently ...

The new boat ramp has a ladder-style frame having C-shaped elongated lateral side rails held in spaced apart parallel condition by C-shaped cross support beams. One end of the frame is a water end and the other end is a shore end. At least six hull roller assemblies are mounted on the side rails in laterally paired relationship across from each other and in longitudinally spaced relationship. One lateral pair is at the water end. Each assembly has a roller axle carrying a hull roller at each end...