Abstract: A fixation component includes tines extending from a base portion of the fixation component. Each tine is elastically deformable between a pre-set position and an open position. Each tine includes a hook segment extending from a proximal end near the base portion to a distal end. Each tine also includes a distal segment extending from the distal end of the hook segment to a tissue-piercing tip. When positioned in the pre-set position, the hook segment extends along a pre-set curvature that encloses an angle between 135 degrees and 270 degrees, and the distal segment extends away from a longitudinal axis of the fixation component.

Abstract: A trailer trammel is provided including a pair of feet assemblies for being rested on a recipient surface. Also included is a trammel releasably connected between the feet assemblies whereby a toe-in of wheels of a vehicle may be determined. During use, the trammel is removable from the feet assemblies for checking a center-to-center axle alignment of the wheels.

Abstract: An electronic bipolar interface driver circuit for interconnecting a microprocessor to an electromagnetic relay load. The driver circuit includes a peripheral adapter circuit having a pair of outputs connected to a respective one of the two inputs of a pair of NAND gates. A source of square-wave signals connected to the other inputs of the two input NAND gates so that a.c. signals are supplied to one of two switching amplifiers. The a.c. signals are transformer-coupled to a pair of rectifiers. The rectified d.c. voltage is supplied to either one of two switching transistors which establishes a given polarity of voltage on a pair of output terminals and which illuminates one of two optical couplers to feedback a checking signal to the peripheral adapter circuit to verify the polarity of the voltage on the output terminals.

Abstract: A fail-safe electronic coincidence detecting circuit including a multiple winding saturable core reactor having a first and a second input winding and an output winding. An NPN transistor amplifier supplying a first pulse train to the first input winding and a PNP transistor amplifier supplying a second pulse train to the second input winding. The output winding producing signal pulses only when the first and second pulse trains are in synchronism.

Abstract: A digital comparator with a comparison cell for each pair of digits of two words stored in separate register banks. Each corresponding pair of register stages is coupled to the associated comparator cell by a rectifier interface network which supplies an actuating signal only when the associated word digits have complementary characteristics. The comparator cells are coupled in series and interfaced to input and output by optical coupler units. Each cell includes an LC network tuned to the selected frequency of an input test signal which is passed through the comparator chain, from highest to lowest order cells, only if each cell is actuated by an input signal from the associated interface network, thus indicating that each pair of word digits is complementary.

Abstract: A selected unique digital comma-free code word is transmitted through track section rails from one end and, when received at the other end, is applied serially to a shift register which supplies a parallel readout of shifting pattern to one input of a fail-safe comparator. The second comparator input is selected from the different possible digital code patterns of the track code word stored in a memory device. When inputs are equivalent, the comparator passes an input test signal to its output. Absence of comparator output causes the selected stored code word to be stepped through the stored patterns, in reverse order to track code shift, until equivalence is again obtained. The periodic output signals, of approximately 50% duty cycle, are processed through a series filter-rectifier network, tuned to test and periodic output signal frequencies, to energize a track relay to register an unoccupied track section indication.

Abstract: A non-linear filter which reduces high signal-to-noise ratio due to sharp and erratic variations in an input signal by charging a storage capacitor through a long time constant charging circuit so that the stored signal level lags an increasing input. A parallel path with a much lower time constant rapidly discharges the capacitor upon input decreases, so that the stored signal matches the more accurate lower input signal level. A practical application is for car space measurements in railroad yard storage tracks to substantially reduce erratic distance measurements due to poor shunting under moving cars. The distance measurement signal is applied through an integrator network to a first of four FET operational amplifiers, whose input and feedback networks have selected time constants to substantially filter out background noise due to the track signal frequency.

Abstract: This disclosure relates to a vital type of d.c. reference voltage supply. The reference voltage supply is coupled to a suitable source of a.c. voltage. A zener diode rectifies the a.c. voltages and regulates the rectified d.c. voltage. A current-limiting resistor is connected from the zener diode to a four-terminal capacitor which charges to a value approximately equal to the zener breakdown voltage minus the diode voltage drop. Hence, a constant d.c. reference voltage is produced when and only when no critical component or circuit failure is present.