Abstract: A control arrangement of a hydraulic vehicle braking system provided with antiskid control equipment includes a master cylinder device which is actuatable by a brake pedal and is provided with at least one master piston cooperating with an associated replenishment chamber. The replenishment chamber is hydraulically connected through a substantially radial bore with the secondary side of the master piston. An axially displaceable circumferentially sealed positioning piston is disposed at the secondary side of the master piston, and a piston rod of the master piston concentrically and sealingly passes through the positioning piston.

Abstract: A fluid reservoir for use with a tandem master cylinder is divided into two compartments by a partition wall with one of the two compartments being directly connected to a first outlet port connected to the master cylinder and the other of the two compartments being connected to a second outlet port connected to the master cylinder disposed in the one of the two compartments by a channel formed within the reservoir extending from the other of the two compartments through the partition wall to the second outlet port. This construction ensures the freest possible arrangement of the first and second ports at the bottom of the reservoir.

Abstract: An arrangement for controlling the pressure in brake actuating cylinders incorporated in a hydraulic vehicle braking system which is supplied with auxiliary energy includes a master cylinder device having at least one master piston accommodated in a bore communicating with a replenishment chamber. A brake pedal actuated control valve device is arranged between the master cylinder device and the brake pedal and controls the supply of auxiliary energy from an auxiliary energy supply source through a hydraulic conduit to the replenishment chamber. Electromagnetically actuatable control valves are included in the braking circuit and locking of the wheels by controlling the operation of the wheel brake actuating cylinders. Furthermore, there is provided a return conduit to a hydraulic reservoir which incorporates a normally open hydraulic shutoff valve which closes when the pressure of the auxiliary energy drops below a predetermined threshold value.

Abstract: A brake pressure regulating valve inserted inside the pressure chamber of a wheel brake cylinder of a vehicle comprises a differential or stepped piston having its smaller diameter section slidably supported in a bore of a wheel brake cylinder piston and its larger diameter section guided in the bore of a housing for the wheel brake cylinder. The larger diameter section of the stepped piston has an internal bore between an inlet chamber and an outlet chamber. A regulating valve controlling the inlet of the internal bore is provided by a sealing ring resting against a surface of the larger diameter section of the stepped piston adjacent the inlet chamber and an adjacent end of the wheel brake cylinder piston.

Abstract: A starting circuit for a high intensity discharge lamp. To provide the high voltage necessary for starting the lamp, the circuit uses a tapped transformer feeding a resistance-capacitance charging network coupled across the lamp. A voltage sensitive symmetrical switch is located in the network between the transformer tap and the RC junction to trigger the circuit when the open circuit voltage of the ballast is at its peak. A diode within the network is in series with resistance to allow current to flow during one half cycle of the cycle allowing the use of an inexpensive resistor in the RC network. A bleed resistor is placed in shunt of the capacitor to stabilize the triggering time of the network.

Abstract: There are known dual-circuit pressure control valves including a pressure control valve having a stepped piston for each of the dual brake circuits with each of the stepped pistons being subjected to a common control force by a circular compensation member. This known device is, however, insecure in its operation and expensive to manufacture due to the material used and the construction of the parts. These disadvantages are overcome in accordance with the present invention by providing a compensation member in the form of a solid of revolution whose radius of curvature is considerably smaller than the radius of curvature of the supporting surface. The control pistons are disposed in a V-shaped with respect to the compensation member.

Abstract: A lighting fixture employing a cover or lens, preferably of flat glass or plastic. A slidable or pivotal retaining clip is provided for either opposite corners or for each corner of the cover. Each clip acts to hold the cover lens without the need for a surround frame. The retainer clips are slidable or pivotal between a hold position clamping the lens to the fixture body and a release position in which the fixture is freed of the retaining or clamping action of the clip. In the release position, the clip is held on the face of the fixture by holding stops on the fixture body.

Abstract: A telephone instrument station circuit using a digital tone generator for generating dual tone multifrequency (DTMF) signals. The circuit employs both series and shunt muting of the receiver during the intervals occurring during the depressive and release movements of the tone generating key or button of the keyblock. The receiver is doubly muted during these intervals to prevent inductively derived spikes from causing audible clicks in the receiver. During the period of tone generation on full depression of the button, the shunt muting is released to allow the full generated tone to be sent to the line, the series muting remaining in effect.

Abstract: A slider switch mechanism especially adapted for use on the steering column of an automotive vehicle for use as a speed control mechanism. The switch mechanism uses a slider constrained to translatory motion within guides of an enclosing housing. The slider is first assembled to a support member and the resulting assembly is fitted into and locked to the enclosing housing. The slider bears a compression spring which is held between axially spaced posts of a support member. The support member is fitted into an opening in one end of the housing and is advanced until a resilient locking member snaps into a cutout in the adjacent wall of the housing. When the support member is fully advanced into the housing, mating holders of the support member and housing are joined to lock the slider assembly into the housing. The slider may then be translated as necessary within the housing cavity, as desired.

Abstract: A digital subscriber terminal equipment is connected to the line circuit at a local exchange via a conventional subscriber line but permits simultaneous transmission of speech and data (e.g., viewdata). The terminal equipment and the line circuit each contain a central unit, a direction-separating unit, and a 10-bit data bus; the terminal equipment also includes a codec with a filter. The central units control the writing and reading of the digital signals into and out of the data bus and form on the subscriber line a main channel for data or speech, an additional channel for control, and an additional data channel.

Abstract: Process control apparatus for reading the condition of a selected variable and for generating a next instruction to be implemented based on the observed condition of the selected variable. The next instruction is that of reading one of two possible instructions, one of which causes the state of an output variable to be read and/or set and the other calls for reading the value of another selected input. In this manner, a program cycle is completed so that the values of all output variables can be set and read.

Abstract: Liquid level control system in which there is a basic resistive level sensing electrode or probe extending into a vessel or tank containing liquid. In addition there is a conductive guard ring or shield insulated from both the probe and from the conductive member or portion of the body of the vessel. The guard ring electrode acts as a current source to counteract electrical leakage across the surfaces between the probe and vessel body to minimize the effects of leakage and maintain the liquid level sensing control operative under most leakage conditions by balancing the leakage currents. In the event the leakage becomes excessive, a control is activated to signal the excessive leakage condition in a suitable manner.

Abstract: A small capacity digital PBX-key system which uses a single processor to control the system. Since only a single processor is employed, the system is interrupt controlled. In the system, there is a codec per line, the codecs each having sufficient programmability to eliminate the need for time slot interchangers. To provide as many as 64 (or more) channels usable for speech, tones and conferencing, two (or more) parallel, 32 channel busses are used as the group bus. The stations and trunks (ports) of the system have access to both busses through the codecs. Information is routed to one or another bus through the transmission of bus control bits from the processor.

Abstract: A conference circuit capable of controlling a plurality of conferences in PCM format. In this system, a person calling a party busy in a two party conversation and wishing to notify the called party of the call initiates camp-on service. The call is transferred to conference channels. The conference circuit performs a comparison between the loudness of the speech sample from each party in a conference to transmit the loudest sample for a second comparison. The second comparison is made against signals generated for providing camp-on tone to existing calls. The loudest sample output indicated by the second comparison is transmitted to the stations of the conference other than the one having generated the loudest signal.

Abstract: A luminaire of otherwise conventional design for street or roadway outdoor lighting which employs as its structural housing, members fabricated of suitable plastic material. The slipfitter structure and the base member on which the weighty electrical components are mounted is made of material having superior tensile strength such as cast aluminum. The aluminum base member is fitted closely and secured to the plastic housing. Thus, the portion of the luminaire most subject to stresses is aluminum while for the larger exterior areas suitable molded plastic may be used. The contours of the aluminum base member form an arched structure for supporting the comparative light weight but physically bulky upper plastic housing. By this construction, the plastic housings are placed in compression but all tensile forces are applied to the base member. In this way the plastic housing merely forms a protective shroud for the luminaire.

Abstract: In a fully digital telephone switching system, a digital switch may serve a number of PCM sub systems each having separate forward and reverse highways and each serving a number of subscribers' lines. The highways are grouped in blocks of eight, from which intelligence is received in serial byte-interleaved form and converted by serial-parallel converters to parallel byte-interleaved form. While in this form they are switched to other channels and applied to a super-multiplexer which they leave in parallel byte-interleaved form from which they are restored by another converter to serial byte-interleaved form for application to the switch's outputs. For the reverse channel the arrangement is the reverse of the above, i.e. serial-parallel conversion, switching and parallel-serial conversion to the line multiplex highways. For local calls a loop-back connection is provided via a fixed delay of half a frame time. Thus, if the outputs fail, the arrangement can still handle local calls.

Abstract: A computer-controlled distributed communication system in which there is a system controller and a plurality of group controllers all interchanging information over a system bus. Each group controller has its individual group bus for the exchange of information between stations of the group and the group controller. Each group controller shares a portion of its random access memory (RAM) with the system controller. When information is directed at approximately the same time to the RAM from a group central processing unit (CPU) bus and from the system CPU bus, the first to access the RAM is enabled to feed its information. Neither bus has any preference. The fed information is stored temporarily in a temporary storage of mailbox RAM in the group. Within the mailbox RAM, separate sections are provided for the storage of information for each direction of information transfer.

Abstract: A luminaire for roadway lighting using a one-piece reflector developing at least two collimated beams in each longitudinal direction. The collimated beams impinge on sloping faces of a refractor to diverge the beams into a regular pattern covering the street with a sharp cutoff at predetermined longitudinal distances from the luminaire. The refractor employs a compressed parabola comprised of radial sections of comparatively large focal length with steps and risers. The complex shape of the one-piece reflector may readily be produced by a reflector finish applied to a molded plastic matrix. In the luminaire, the prismatic surfaces of the inclined walls of the refractor diverge the formerly collimated beams in a carefully controlled manner to produce very uniform distribution of light.

Abstract: The direct current line feed for a telephone subscriber's line is derived from a variable voltage source connected to the line. In one case, the source is series connected in one leg of the line while in the other case it is connected across the line. In the first case there is a constant current source across the line while in the second case the voltage source is a constant current device. In both cases a pair of matching resistors is connected across the line with the center tap grounded to provide a high resistance balanced termination for the line. In both cases a high impedance monitor is connected across the line to monitor the voltage conditions on the line, and this, via a control circuit controls the voltage source and the separate constant current device if provided. This enables line voltage to be adjusted to take account of line length without introducing undesirably large dissipation.

Abstract: A digital MFC receiver using single band and multiband filters. The single band filters are tuned to respective ones of the signal frequencies. The multiband filters are used as guard filters producing interleaved guard bands between the signalling frequencies. A processor is used to test and evaluate received signals, the processor being programmable to evaluate signals to different specifications.