Abstract: A Tee slot blade antenna for aircraft and other high speed vehicles has a pair of dielectric sections, one section extending longitudinally along the blade and the other extending transversely from an intermediate location along the longitudinal section. The resonant frequency of the antenna is determined by the length of each section and the position of the transverse section along the longitudinal one, while the characteristic impedance is a function of the width of each section. The Tee slot antenna is capable of operating over a wide bandwidth on a smaller blade than prior single slot antennas. A Tee slot antenna designed for one frequency range can be combined with either a single slot antenna or another Tee slot antenna designed for another frequency range on the same antenna blade, without impairing the bandwidth of either antenna.

Abstract: An integrated current mirror circuit in which a compensation transistor is added in each stage of the mirror to compensate for the base-substrate leakage currents of the other transistors in the mirror circuit and to keep the circuit operative even at high temperatures and low current levels. Each compensation transistor is matched with the other transistors in its stage and has its collector-emitter circuit connected between a voltage source terminal and the common base connection of the other transistors. The base of each compensation transistor is unconnected to the remainder of the circuit but exhibits a base-substrate leakage current which is employed in the compensation scheme.

Abstract: A protective pad includes a sheet of flexible material. A plurality of fasteners are spaced around the edge of the sheet in the corners, and adjacent fasteners can be attached to each other. When the fasteners are attached, the edge of the sheet is forced upward slightly to form a lip around the top face of the pad to retain soil, debris and water. When the fasteners are not attached, the flexible material lies flat. Handles across opposite corners are used to fold the pad and to carry it.

Abstract: A traction device for providing relief to the spinal column in which a person is suspended from the midsection over a pair of support pads. The angular position of each support pad is independently adjustable, thereby enabling the stretching effect of the traction device to be specifically tailored for the particular injury being treated. A control mechanism for adjusting and locking the angular position of each pad, and a pad with a generally saddle-shaped profile is described.

Abstract: An improved input current compensation circuit is provided for a superbeta transistor amplifier. The circuit has a pair of compensation transistors which simulate the amplifier transistors and support a base current which is mirrored back to the amplifier circuit to cancel the input currents thereof. The compensation transistors are supplied with base current by a control transistor. A special voltage control circuit is provided to establish controlled collector-emitter voltages for the compensation transistors independent of the control transistor, thereby decoupling the compensation transistors from the uncertain effects of the control transistor's base-emitter voltage. The control circuit is connected from the collector of one compensation transistor to the emitter of the other, and is provided with primary and secondary current sources to establish a current flow that sets up a desired bias for the control transistor and results in a near exact cancellation of input bias current.

Abstract: A microstrip antenna which includes a ground member, a dielectric element mounted on the ground member and a radiating element on the dielectric element, has been improved by means of a distinct grounding ring of conductive material which is spaced apart from and extends around the radiating element. The grounding ring is connected to a ground member, thereby laterally isolating the antenna and permitting a closer spacing with adjacent antennas. The gap between the radiating element and the grounding ring is different in different directions.

Abstract: A housing of substantially the same shape and size of a magnetic tape cassette is adapted to be inserted within the cassette receiving aperture of the magnetic tape playback/recording unit. Three resiliently biased arms are independently and rotatably coupled about pivotal points within the cassette housing. The disposition of the tape head and the capstan roller of the playback/recording unit causes the capstan drive to initiate rotation of a coupled gear train linking the independently rotatable arms. The surface used to clean the magnetic tape head is coupled to the capstan driven gear, the resilient forces biasing the independent arms maintaining pressure against the magnetic tape head while the housing holding the cleaning apparatus is maintained within the playback/recording unit.

Abstract: The vacuum chamber includes an airtight generally cylindrical wall and a pair of end members. Vacuum pumps in the chamber evacuate the chamber. The chamber is rotated along the longitudinal axis whereby the centrifugal force of the rotating cylindrical wall acts against the force resulting from the pressure differential between the inside of the evaluated chamber and ambient pressure on the outside of the cylindrical wall to prevent the cylindrical wall from collapsing. An inner member is mounted in the chamber, but the chamber rotates with respect to the inner member. In a low temperature embodiment for freeze drying refrigerated air cools the outside of the chamber to reduce the temperature within the chamber. The consensables condense on the inside of the cold cylindrical wall.

Abstract: A bias circuit for an FET switch in which a pinch-off voltage is generated and sets up a current through a first resistor. The current is reflected through a second resistor to establish a voltage differential across the second resistor which is then imposed across the gate-source terminals of the switch FET when it is desired to turn the switch OFF. The relationship of the turn-off voltage imposed across the switch FET to its pinch-off voltage is determined by the ratio of the resistance values of the two matched resistors, which ratio is independent process and temperature. The switch bias circuit thus offers highly reliable operation and at the same time a greatly reduced power consumption.

Abstract: A metering device for particulate material in which backups and caking of material is inhibited by the provision of a "live" metering gate consisting of an upper blocking section and a lower material contacting surface. The lower surface is continually moved in the direction of material flow at a speed approximately equal to or slightly greater than the material flow speed. An elongate rotatable rod carried at the lower end of a blocking plate preferably provides the material contacting surface.The gate is vertically adjustable so that the volumetric flow rate of material can be controlled. In a preferred embodiment the gate is located above the end of the material bearing surface and is adjustable along an axis which diverges from vertical by an appreciable angle, preferably about 45.degree..The transverse dimension of metered material is also controlled by means of two blocking members which extend inwardly toward each other from behind the gate.

Abstract: The vacuum chamber includes an airtight generally cylindrical wall and a pair of end members. Vacuum pumps in the chamber evacuate the chamber. The chamber is rotated along the longitudinal axis whereby the centrifugal force of the rotating cylindrical wall acts against the force resulting from the pressure differential between the inside of the evaluated chamber and ambient pressure on the outside of the cylindrical wall to prevent the cylindrical wall from collapsing. An inner member is mounted in the chamber, but the chamber rotates with respect to the inner member. In a low temperature embodiment for freeze drying refrigerated air cools the outside of the chamber to reduce the temperature within the chamber. The consensables condense on the inside of the cold cylindrical wall.

Abstract: An alarm system for bicycles and the like in which a collar having an undulating exterior surface is mounted on the handlebar post and rotates therewith. A moveable trigger member, preferably a spring biased pin, is mounted to the bicycle chassis adjacent the collar. Unauthorized rotation of the handlebars causes the collar to rotate against the trigger member, moving that member to close a set of contacts and thereby complete an electrical alarm circuit. The alarm circuit is controlled by a latching relay which hold the alarm on until either an automatic timing device operates to terminate the alarm, or the system is turned off by a key-operated lock. The trigger member closes another set of contacts to actuate the alarm if the bicycle is tampered with by removing the collar.