Abstract: A mechanism used for locking a valve that provides positive control of the valve lock to prevent the valve from changing position unintentionally. The positive locking valve control device preferably comprises a push-pull rod having a toothed configuration that is engaged at different positions by a spring mechanism on the valve locking device in order to hold the push-pull rod and thereby the valve securely in place. To adjust the opening of the valve, the push-pull rod can be rotated by some predefined amount (such as 90 degrees) clockwise or counter-clockwise. This rotation frees the locking spring on the valve locking device from the teeth aligning it with a side of the push-pull rod thereby permitting linear movement of the rod to cause a corresponding adjustment in valve position. The rod is then “pushed in” or “pulled out” to adjust the size of the valve opening until the desired flow through the valve is obtained.

Abstract: A ballast circuit for a discharge tube such as a fluorescent tube, mercury vapor, sodium vapor or metal halide lamp is disclosed. D.C. power is provided alternately between two output driver stages and an a.c. neutral return line. In output transformerless (OTL) embodiments of the invention, a series connection of a reactance circuit and the tube is connected between the push pull point and the a.c. neutral return line. In transformer embodiments of the invention, a primary winding of a transformer is connected in series with the reactance circuit. The tube or load is connected across an output winding of the transformer with the electrical effect that the load is in series with the reactance circuit. Alternative arrangements of transformer input windings are provided. The first includes two input primary windings wound in opposite directions with the circuit arranged such that current flows in one or the other of the input transformer windings on alternating half cycles of the control signal.

Abstract: An electronic ballast for high intensity discharge lamps is taught. A high speed electronic switch gates voltage across the lamp only for that period of time when the amount of resultant current flow will not adversely affect the lamp or the switch. At that point, the voltage is gated off for a period of time, after which the cycle repeats. This scheme eliminates the need for any inductive, resistive or capactive element, either saturable or conventional, in the post-ignition operation of the lamp, except perhaps for auxiliary functions. The elimination of such inductive elements results in a highly efficient, low cost electronic ballast having reduced electromagnetic and radio interference emissions.

Abstract: A lighting fixture is disclosed for accommodating a bulb parallel to its opening and that has a reflector made from a thin metal sheet located behind the bulb. At each socket housing location, the reflector is slit and an arc piece is formed from the released metal segment. The arc piece forms an effective shield over the socket and related components. Thus, the reflector and shield or shields are formable in a single action stamping step by appropriate manufacturing equipment.

Abstract: A temperature switch for HID lamp fixtures is provided to enable such lights to be operated at low temperatures on the order of minus forty degrees Celsius, or minus fifteen degrees Fahrenheit. In one embodiment, the switch is comprised of a thermistor circuit and a resistive photocell circuit. When the resistance of either the thermistor or the photocell exceeds the reference value, or when the combined resistance of thermistor and the photocell exceed that value, the HID lamp will be turned on. The lamp is thereby turned on when the ambient temperature becomes very cold, regardless of the amount of ambient light in order that the components of the light fixture may be heated internally for more reliable operation.

Abstract: A striker circuit is provided for high intensity discharge lamps that uses a clamping circuit applied to the AC line current to generate a clamped voltage differential for striking the lamp. A clamped voltage differential is generated at fixed intervals until the lamp is struck. The emission of the clamped voltage differentials is stopped when the current flowing through the lamp is above a fixed value. The clamped voltage differential is reclamped if it drifts from its desired, clamped waveform.