Abstract: An apparatus for detecting the presence and/or direction and/or velocity of a moving ferromagnetic element is provided. A sensing coil is placed in coupling relationship with a bi-stable ferromagnetic wire to provide a signal in response to a change in polarity of the core of the bi-stable wire. The core polarity changes in response to element presence as the element constitutes a magnetic shunt causing a change in magnetic flux density and/or direction in the air gap of a magnetic circuit in which the bi-stable wire is situated. The sensor is substantially insensitive to element velocity. Modified structures provide for fail-safe operation.

Abstract: An alarm or signalling system between a transmitter station and a receiver station either or both of which may be in motion. A signal is selectively radiated from the transmitter station for detection at the receiver station. The receiver station includes processing means for responding to the received signal and producing a new signal indicative of selected physical relationships between the transmitter and receiver stations during the period of signal transmission and reception. The modified signal may indicate approaching or departing relative motion and/or magnitude of separation. One embodiment may incorporate synchronizing signals transmitted from a central control station. This embodiment may include receiver stations with and without the synchronizing equipment.

Abstract: A simplified linkage and cam member having first and second cam surfaces for interacting with a bail to drive said bail between first and second limits is provided. The cam surfaces restrict the movement of the bail when the bail is at either limit. However, when the bail is intermediate of the limits, the relationship of the effective portions of the cam surfaces allow increased bail movement for a given position of the cam member and associated cam surfaces. The structure is particularly well adapted for actuating a bail from a first to a second position wherein forces other than those applied by the cam also act on the bail; and at a critical bail position, the other forces take control and urge continued motion of the bail independent of the cam member.

Abstract: An electrical fitting for use in a conduit run which includes a sealing chamber into which a compound is placed to prevent the passage of gasses, vapors, or flames from one end of the fitting to the other. The fitting includes a drainage port to prevent the collection of water and a filling port through which the sealing compound is placed in the sealing chamber. The drainage port and sealing chamber have coplanar upper limits whereby any excess sealing compound placed in the sealing chamber is drained off through the drainage port. An interior shield member of the body shields the upper opening of the drainage port whereby no sealing compound can enter the drainage port directly from the filling port. Thus, there can be no flow of sealing compound through the drainage port until the sealing chamber has been filled. Underfill and overfill of the sealing chamber are prevented, and no core or plug projects upward from the drainage port during filling.

Abstract: A circuit for distinguishing between two classes of alarms on a single loop. An alarm of a first class causes an impedance of a first predetermined value to be added in the loop; and an alarm of a second class causes a much larger additional impedance, or an open condition, to be inserted in the loop. The loop is bridged across an element of a voltage divider and, therefore, the loop characteristics, including the changed characteristics due to the impedance change in response to an alarm of either class, controls the potential of a test point of the voltage divider. Voltage comparators monitor the potential of the test point relative to control potentials, and cause relays to provide a no alarm signal, a first alarm signal, or a second alarm signal when there is no alarm condition on the loop, an alarm of the first class, or an alarm of the second class, respectively, on the loop.

Abstract: A liquid tight fitting for liquid tight flexible metal conduit which provides higher unit sealing pressures and improved liquid tight sealing by providing line, rather than surface, contact at critical points. The body member of the fitting makes line contact with a flared lip of the ferrule. The lip of the ferrule makes line contact with the sealing ring. The vector forces which create the seals have components in the directions required to most effectively and efficiently produce the seals. The sealing ring may be made symmetrical, is discontinuous, has an inside bead for sealing against the conduit and may include wings for retention in the gland nut prior to assembly of the fitting on a conduit end.

Abstract: An electrically actuated audible alarm having a magnetic structure comprising an assembly of laminations is provided to reduce eddy current losses. With the reduction of eddy current losses, faster magnetic flux buildup is possible and an increased velocity of striker and/or armature movement. The increased striker velocity permits delivery of a given quantum of energy to the gong with a reduced striker mass which in turn facilitates even greater velocity. When actuated from an a.c. current source, a diode may be used in series with the winding to interrupt magnetic flux generation on negative half cycles and permit return movement of armature and striker. Conventional interrupter contacts may be used when actuated from a d.c. source. A series diode provides for d.c. loop supervision. A multiple lead permits the audible alarm to comprise part of the loop circuit and thereby provide a supervisory signal if an audible alarm is missing.

Abstract: In many assemblies it is desirable to provide a strain relief device to grip an electric cord to prevent longitudinal motion of the cord, with respect to the strain relief device. The disclosed strain relief member surrounds the electric cord and is enclosed within a body member which, when assembled, applies longitudinal compressive forces on said strain relief member to cause a central portion thereof to collapse axially inward and grippingly engage the electric cord. The central portion may include serrations for improved restraining of the cord. The strain relief member may be made of plastic or metal and may include central perforations and/or portions of different thicknesses to facilitate and control the collapse. A metallic strain relief member may serve ground metal sheathed cable. A resilient membrane in a plane normal to the longitudinal axis of the cord and the strain relief member may be used between the strain relief member and the body member to provide a liquid tight seal.

Abstract: A carpet cleaning machine having a scrub brush, independent means for selectively delivering cleaning and rinse solutions, and vacuum means for removing the solutions and entrained dirt. A cleaning head is moved about the carpet on a pair of wheels by an attached operating handle which includes means for controlling the volume and timing of the release of the solutions. The wheels are so located, with respect to the center of gravity of the head, that the scrub brush is normally in contact with the carpet. However, in response to appropriate manipulation of the operating handle, the head is pivoted about the axis of the wheels and the scrub brush is lifted from the carpet and the vacuum nozzle brought in contact with the carpet. A pump is used to deliver rinse solution from a reservoir to the head by a flexible hose and the vacuumed waste is delivered to a remote collection chamber through a flexible hose and a portion of the operating handle. To protect the rinse solution pump, a bypass loop is provided.

Abstract: An improved buzzer structure is designed for automated assembly and comprises a housing, a coil wound on a bobbin, a magnetic frame, and an armature mounted for reciprocating movement between a coil core and a diaphragm. The magnetic frame includes parallel side members which mate with parallel edges of the bobbin flange for guiding and orienting the bobbin as it is inserted in the preformed frame. The frame also includes parallel top and bottom members separated by an amount slightly in excess of the bobbin height so as not to restrict bobbin insertion. The bobbin has a coupled coil terminal which mates with an arch on the frame for providing an electrical connection therebetween. An area of light pressure contact between the bobbin and frame, and starting at an intermediate point of bobbin insertion, is provided for maintaining a fixed relationship between the bobbin and the frame after the bobbin has been inserted to a predetermined relationship with respect to the frame.

Abstract: A cast bus bar clamp with perimetric ribs and a connecting web is provided. The design eliminates abrupt changes in cross-sectional area. This, in turn, provides a less abrupt temperature gradient on cooling which, in turn, minimizes nonuniform solidification which, if present, frequently causes the formation of weakening cracks. To improve the distribution of clamping pressure, the clamp is usually given a convex curvature so that when the clamp is tightened there are five pressure points. The design provides an improved strength-to-weight ratio and a more reliable and economical structure.

Abstract: There is disclosed a circuit for energizing a vital relay in response to an input signal that is modulated between two frequencies. A discriminator circuit responds to the modulated frequencies and alternately produces an output patented of one polarity and then a reverse polarity in response to the modulated signals. Coupled between the discriminator and the vital relay is a relay driver which responds to the output of the discriminator and energizes the vital relay. A d.c. power supply is coupled to the relay driver. The vital relay includes two windings. Failure of the modulation, the d.c. source or virtually any circuit element, will result in release of the vital relay. The disclosed embodiment uses photoresistors as switching elements.

Abstract: A selected predetermined coded alarm is provided indicative of the one of a plurality of leads on which a signal indicative of an alarm condition may appear. If a station coded alarm should be initiated during the transmission of a coded alarm, the coded alarm is immediately terminated and the station coded alarm is given priority and transmitted immediately. Upon completion of the station coded alarm, the coded alarm being transmitted at the time of the receipt of the station coded alarm is transmitted with the new transmission starting at the start of its code irrespective of the status of the transmission at the time of the interruption. Appropriate delays are provided between codes and code elements. The plurality of leads are sequentially scanned, but once a transmitted code is transmitted, it is not retransmitted on a subsequent scan unless a reset signal has been provided. Each transmitted code is repeated a predetermined number of times.

Abstract: A selectively adjustable air deflecting damper is provided in the air exhaust barrel of an electrically heated hand-held hair drier for adjusting the area of the air discharge orifice and concomitantly the air velocity of the heated air discharge. The damper is pivoted in the barrel downstream of the air heating element and is selectively movable between first and second positions providing maximum and minimum effective orifice openings for producing a dispersed and a concentrated air flow, respectively. The damper is spring biased to its first position and operated by a trigger arranged for actuation by a digit of the hand holding the hair drier during use.

Abstract: In some circumstances it is important to maintain a d.c. potential within a specific range of a critical value. The circuit shown will provide a fail-safe signal if the potential deviates from the allowed range. Two zener diodes and two optically coupled isolators are used. If the d.c. potential remains within the critical range, an a.c. test signal back biases one optically coupled isolator and forward biases the other on the positive half cycle; and on the negative half cycle back biases the other and forward biases the one. Thus the two optically coupled isolators conduct on alternate half cycles of the a.c. test signal. If the d.c. potential strays from the required range, the optically coupled isolators stop alternate conduction and a fail signal is given. If either zener diode should fail in a mode which alters its characteristics so that the circuit would fail to detect a voltage excursion outside the allowed range, a fail signal is given.

Abstract: A liquid tight connector for joining a liquid tight flexible conduit to a junction box or panel and having improved ground continuity is provided. The connector includes a body member having a cast-on lug to which an external ground may be secured. To provide a liquid tight seal between the fitting and the junction box, channel or raceway, an O-ring or similar seal is provided. The O-ring is placed in a recess whose depth and cross section are so related to the size and characteristics of the O-ring, that when the O-ring provides a liquid tight seal, a metallic surface of the body is in contact with the joined metallic member. With this increased metallic contact, there is an improved capacity to conduct fault current. The recess may be positioned to provide substantial contact area on an appropriate side of the perimeter of the O-ring. This protects the contact area from rust and/or corrosion which would reduce the fault current carrying capacity.

Abstract: One or more radially projecting tabs are provided on a discontinuous ring for retaining the ring in proper association with a body member in spite of movement or vibration of the assembly. The tab, or tabs, mate with a grooved section of the body member. The groove may comprise a thread. The ring may be internal or external to the body member. The retaining tab will project radially outward or inward when the ring is to be internal or external, respectively, to the body member. The tabs have an axial thickness of the order of 25 percent, or less that of the ring. To provide secondary internal retaining means, a portion of the ring may be cut from an oversize ring so that a stress is formed when the ring is closed for inserting the ring in an internal opening. When a ring is to be used external to a body member, a simple cut may be made in an undersize ring so that a stress is formed when the ring is opened for placement external to the body member.

Abstract: A track circuit signalling system for an electrified rapid transit system using significantly fewer components is provided. Instead of a transmitter and receiver at each track circuit boundary, alternate boundaries have transmitters only; and the intermediate boundaries have two receivers. The coupling units for the two receivers are more economical than the prior art coupling unit for coupling the transmitter-receiver combination. The transmitters on each side of a receiver pair transmit signals on different carrier frequencies. Each transmitter transmits in both directions from its location. Of the two receivers at a given boundary, one is tuned to respond to signals from the transmitter on one side, while the other receiver of the pair is tuned to respond to signals from the transmitter on the other side. For special applications using overlapping track circuits, selected transmitters may be omitted and a single receiver used on each side of the omitted transmitter.

Abstract: A dynamic loudspeaker is driven by chopped d.c. from the collector of a transistor. A free wheeling diode is connected in parallel with the speaker circuit to dissipate the inductive energy in the speaker voice coil when the transistor is turned off. The transistor is controlled by a voltage controlled oscillator which, under control of other elements, can be made to produce a wide variety of cyclically varying output signals for producing a wide range of sounds, tones and signals from the loudspeaker. This permits selection of a tone which differs sufficiently from the ambient noise to assure attracting attention. By the use of chopped d.c. to drive the speaker, the expense, weight and bulk of an impedance matching transformer is eliminated. A plurality of individually operable switches are provided for switching circuit elements in and out of circuit to modify wave shapes and alter sound output.

Abstract: Penetrations or passageways through fire rated or fire resistant walls, floors, partitions, and ceilings are frequently necessary to provide for present or future pipes, cables or conduits. A fitting placed in the penetration provides a seal to prevent the passing of fire, products of combustion, gas vapor or liquid through the penetration under normal conditions and under adverse conditions of fire or elevated temperatures. The fitting includes an elastomeric-like material, under pressure, which provides the initial barrier. An intumescent material, which responds to heat is provided to expand and fill any void created by the degeneration of the elastomeric material in response to the heat or fire. The fitting may include an outer exposed layer of intumescent material to serve as an insulator.