Abstract: In various types of systems it is expedient to have a plurality of control consoles, each assigned a relative priority so that they may control the associated equipment in a predetermined hierarchy. The priority wiring requires only a pair of wires from one console to the next. A higher priority console, when activated, disables all lower priority consoles in the hierarchy and an indicator at each disabled console is activated to indicate the disablement. The indicator at the active console is not activated and the indicator at the highest priority console is, of course, never activated. Power to activate the disablement indicators is provided from the higher priority active console.

Abstract: A single zone system which may use a single cable pair for both detectors of nonstandard conditions and audio/visual alarms. The audio/visual alarms are polarity responsive and in response to an alarm detection, comprising an increase in line current, the polarity is reversed and the line current supervision circuit disconnected. Some detectors or signaling devices may be polarity sensitive so that they present a high impedance under normal and reverse polarity conditions, and a lower impedance on abnormal conditions and prior to polarity reversal. Other detectors may be polarity insensitive and include a relay which may be activated from line potential subsequent to detection of an abnormal condition. The relay may be used to operate door closers or to initiate other appropriate action.

Abstract: An alarm detection, indication and supervision circuit with reduced power drain during failure of commerical power supply whereby standby batteries may maintain detection capability for an extended period. Separate detection and alarm indication loops are provided each with an end-of-line resistor which is removed from the circuit in response to a commercial power failure. A nearly unlimited number of detectors may be used on the detection circuit and each may have an auxiliary relay for control of local apparatus to permit local control, under changing ambient conditions. In response to an alarm signal, the potential on both loops is switched from a limited current supply to a hard supply and the polarity is reversed.

Abstract: A combined audio and visual signal unit with the audio and visual components actuated alternately and powered over a single cable pair in such a manner that only one of the audio and visual components is drawing power from the power supply at any given instant. Thus, the power supply is never called upon to provide more energy than that drawn by the one of the components having the greater power requirement. This is particularly advantageous when several combined audio and visual signal units are coupled in parallel on one cable pair. Typically, the signal unit may comprise a horn and a strobe light for a fire alarm signalling system.

Abstract: An ionization smoke detector device including means for insuring that adjustment can be made in the triggering potential for the alarm device so that should circumstances change, an operator can make a simple adjustment to take into account the changed circumstances. This means comprises a programmable Zener diode which is connected to a voltage dividing resistance network at the output of a field effect transistor, the other end of the Zener diode being connected to the input of a silicon controlled rectifier device which functions to trigger the alarm.Another primary feature of the present invention is the provision of a means for testing the operation of the system in such a way that all of the elements of the system will be tested rather than merely some of them.

Abstract: Circuit means for synthesizing the sound of a mechanical bell by combining the three most significant frequencies of the bell to be synthesized and modulating these with a decaying exponential control signal which is derived from a clock signal having a pulse repetition rate equal to the stroke repetition rate of the bell being synthesized. The combined and modulated signal is amplified and coupled to suitable audio distribution means. Modulation of the exponential signal can provide a tremolo effect.

Abstract: A threaded insert plug for at least temporarily closing an opening in an internally threaded member. The plug member comprises a right circular cylinder closed at the lower end thereof. The closing surface includes an upstanding central portion proportioned to permit the application of a wrench and may include a screwdriver slot on an upper surface. The interior of the cylinder includes critically positioned projections and/or depressions which permits use of a lever having an end positioned against the projection or depression and a mid-portion against at least part of the upstanding central portion to permit the production of a turning torque. The surface irregularities may be configured and positioned to permit engagement with a suitable wrench. The walls of the plug may have generally uniform thickness thereby providing an economical and minimum weight plug. The upper surface of the upstanding central portion rises no further than the plane including the upper limit of the plug member.

Abstract: A lamp socket adapted for mounting on a printed circuit board or other support member. The lamp socket comprises a non-conducting housing having a first contact member captured in cooperative relationship therewith such that one part of the contact member is positioned to make electrical contact with one terminal of a lamp inserted in the socket. The first contact member includes a second part for projecting through an opening in the base of the socket for making an external electrical connection therewith. A second contact member is captured in cooperative relationship with the housing and includes one part that is positioned to make contact with another terminal of a lamp inserted in the socket. The second contact member includes a second part for projecting through an opening in the base of the socket for making an external electrical connection therewith. One of said contact members is captured by a latch member formed as a part of said housing.

Abstract: A lay-in lug to be coupled to a bushing, or the like, for providing a low resistance grounding connection between a wire secured in the lug and the bushing. The lug comprises a body member and a conduction member for providing strength and a low resistance conduction path, respectively. The body member supports the conduction member and includes resilience to compensate for cold flow of the laid-in wire. The conduction member is in direct contact with both the laid-in wire and the bushing to provide superior conduction between the wire and the bushing. In addition, the wire is pressed against one side of the back portion of the body member and the reverse side of the back of the body member is in direct contact with a back section of the conduction member.

Abstract: A circuit for controlling the intermittent application of a dc potential to a device, such as a striker mechanism for a gong, having a member reciprocally moveable between rest and active positions. The reciprocating member shunts and unshunts a capacitor when the member is in its rest position and moved away therefrom, respectively. While the capacitor is shorted, and during its charge time, dc power is applied to the device. When the capacitor is charged to a predetermined potential, dc power is disconnected from the device thereby allowing the reciprocating member to return to its rest position to shunt the capacitor and initiate a new cycle of operation. The system is substantially independent of mechanical characteristics of the device and the current interrupted or made by the contact pair may be at least an order of magnitude less than the peak current in said device.

Abstract: A clamp for grounding and clamping a conduit to a support member, such as a cable tray, and comprising a relatively thin pad member interposed between the conduit and the support member. The pad member includes serrations, knurling and/or other surface discontinuities, but is otherwise configured to mate with the conduit and the support member so that when pressure is applied between the mating surfaces a good electrical contact is achieved. The required pressure is provided, for example, by a jaw member and a U-bolt working in combination with the other members such that the jaw contacts the support member opposite at least a portion of the pad in contact with the support member. The ends of the U-bolt pass through the pad and the jaw member so that nuts installed on the ends of the U-bolt cause the conduit to be pressed into the pad. The jaw and the pad securely clamp the support member.

Abstract: An improved signal light employing a deep-dish reflector and critically positioned mask or masks for blocking at least some selected light rays having their origin in an external source to reduce, or eliminate, phantom signals. The mask is effective to block out at least a portion of the reflector which reflects light, from an external source, back out of the signal in a direction parallel to the reflector axis. The mask may take the form of a planar ring, a cylindrical surface, a cone or portions thereof. Other shapes may prove expedient or the reflector may be treated in selected and controlled locations to inhibit reflection. The mask may comprise any suitable material such as an opaque material or an electrically controlled optical shutter which is closed when it is desired to inhibit phantom signals and opened to accommodate normal signals.

Abstract: This disclosure relates to an apparatus for fire alarm signaling which is economical and versatile and which makes use of the properties and characteristics of the material of which it is made. All components of the assembly snap together. An auxiliary cover as well as the main cover may be used. A lower break-rod is mounted on the base and cammed aside as the main cover is closed and then the break-rod returned to a position to be broken in response to opening the main cover, an upper break-rod may be associated with the auxiliary cover. Up to three switches may be provided and each has a latched position. A simple tool is used to release the switch latch. The latch comprises an integral part of the base and/or switch stems. During assembly selected elements may be selectively oriented to make any switch have either normally-open or normally-closed contacts. The catch between the main cover and base permits easy actuation and yet inhibits false actuation in response to a blow. No internal wiring is required.

Abstract: A compact and economical circuit for a multitone horn employing a microcomputer. The system also includes an audio amplifier, a speaker, a power supply, and start control means. The start control means includes a common lead and a plurality of star leads. Connecting the common lead to a predetermined one of the start leads will initiate a predetermined one of the plurality of available tones. A selected one of the start leads may have priority to terminate any pre-existing signal and initiate an alternate signal. At least one of the start leads, including the priority start lead, may be coupled to programming means whereby the signal activated may be preprogrammed to be any selected one of the plurality of available signals. The power supply includes a pulse generator for resetting the microcomputer in response to initial application of power. The available tones include both percussive and non-percussive tones and the total number of available tones may be greater than the number of start leads.

Abstract: A poke-through electrical fitting device for placement in a passageway such as a cylindrical hole through a wall, floor, or the like, which may be made of concrete or some other fire rated barrier. The fitting is designed to prevent the spread of fire from one side of the fire rated barrier to the other, to protect the conductors and to facilitate installation, by requiring minimum disassembly or assembly during the installation which may be accomplished by a single craftsman. The fitting includes a channel member through which the conductors pass. Pivotally coupled to the channel member are spring biased wing members which extend laterally and which include wedge points for binding engagement with the interior of the passageway. The wing members and wedge points may be released from the underside to facilitate removal of the fitting. A thermal barrier is included to inhibit heat transfer, and other sealing members are provided as a barrier to any products of combustion.

Abstract: A poke-through electrical fitting for protecting and supporting a wire or cable as it passes through a fire rated barrier and which will fit through a standard knock out of an electrical fitting box which is one and three-eighths inches in diameter and which, in the trade, is called a one inch knock out. The fitting does not require an electrical fitting box on both sides of the barrier. The device comprises an elastomeric grommet having an appropriately sized transverse hole and a slit from the outer periphery to the hole for permitting opening of the grommet and laying in of the wire or cable. An upper and lower compression plate is provided on each end of the grommet and coupling screws are provided for compressing the grommet between the compression plates to cause the elastomeric grommet to grasp the wire and close the passageway through the barrier. The lower compression plate has a clamp for clamping and supporting any cable of the size range which may be accommodated by the device.

Abstract: A detector circuit for detecting an unwanted ground coupled to either terminal of an ungrounded d.c. power supply. The circuit uses simple and economical components including four resistors, two diodes and a single voltage comparator. The resistors provide two voltage dividers whose midpoints are at different potentials. The two midpoints are coupled by the two diodes in series with the midpoint of the diodes grounded. A voltage comparator is coupled to the voltage divider midpoints. Any unwanted ground will shift the relative polarity of the voltage divider midpoints and alter the output signal of the voltage comparator.

Abstract: At a railroad crossing, a single motion detection unit is selectively coupled to an occupied track in such manner that safe, effective and efficient control is obtained over the crossing alarm device. The means for coupling the motion detection unit includes means for terminating the activation of the crossing alarm device when a train stops on the approach track, but short of the actual intersection. Techniques for multiplexing a motion detection unit with plural tracks at the grade crossing or with multiple track circuits on a single track are provided. Safe operation is assured with multiple track occupancy irrespective of the sequence of occupancy and which is the last to remain occupied or if one of the trains stops or reverses direction of motion.

Abstract: To assure safety, an expansion joint in an electrical system must have grounding continuity. A telescoping unit is provided using a braided-conductor bond inside the joint thereby protecting it from ambient contaminants. A high integrity ground continuity is assured even if the conduit is painted or becomes corroded. Selected components are proportioned with respect to each other to assure accurate component alignment with no possibility of relative movement, during assembly, which would endanger ground continuity. Stop means are incorporated in the design to limit the twisting of the grounding jumper during assembly.

Abstract: A lay-in lug which may be used for a grounding connection by securing it to a conductive bushing, or the like, is disclosed. The lug comprises a body member for providing strength and rigidity and a conducting member, supported by the body member, for providing a low resistance conduction path. The conducting member is in direct contact with both the laid-in wire and the bushing, or the like, whereby a low resistance conduction path is provided between the wire and the bushing. First and second clamping means secure the lug to the bushing and hold the wire in contact with the conducting means, respectively. The conducting member may be selectively removable from the body member and may include a turned-up lip for helping to retain a wire in contact therewith. The conducting member may also include means for inducing slight deformation of a wire compressed thereagainst to increase the pull-out force required to extract the wire.