Abstract: A drum for transportation of flexible electrical cables has an oval cross-section and is formed of a spool member comprising a pair of semi-cylindrical sections and means for rigidly maintaining the sections with their diametric surfaces spaced parallel to and facing each other. A planar retainer member of corresponding oval cross-section and uniformly greater dimensions than the spool member is secured to each flat end of the spool member transverse to the axes of rotation of the sections to form a pair of spaced opposed walls of a rectangular slot receiving at least one layer of a continuous length of cable for shipment.

Abstract: A cutter for a helically corrugated tube in which a pair of rings are connected by a blade carrier to form a track around the tube. Each of the rings comprises a pair of "C" members hingedly connected at one end and releasably connectable at the other end to form the ring. Each "C" member has a pair of rails supporting a circumferentially movable carrier having rollers at each end engaging the rails of the adjacent pair of rings. A holder on the carrier projects outwardly between the rails. A yoke in the holder carries the cutting blade; a compression spring in the holder drives the yoke and blade toward the tube. A threaded cup on the holder adjusts the compression spring and also provides a handle recess.

Abstract: A removable and replaceable solid state trip unit assembly for automatically opening a molded case multi-pole circuit breaker, is constructed so as to be interchangeable with a thermal-magnetic trip unit assembly.

Abstract: A solid state tripping circuit for sensing overcurrent conditions in a circuit connecting a power source to a load circuit and for controlling the operation of a circuit breaker in series in the circuit. The tripping circuit is responsive to different levels of current flow in the protected circuit to actuate the circuit breaker to the open condition after a variable time delay. The duration of the delay time is a function of the ratio of the overcurrent sensed to the rated circuit current. Energy for operation of the tripping circuit is supplied directly by the sensing circuit to eliminate a separate power supply.

Abstract: The present invention provides a coupling member for joining two generally coaxial, tubular members such as an electrical conduit. The coupling member includes internal left hand threads at one end and internal right hand threads at the other end with an annular groove therebetween. One end of a first conduit is provided with two sets of axially spaced apart external left hand threads. The coupling member is rotated so that the left hand threads thereof matingly engage the first set of left hand threads on the conduit and then is temporarily locked by engagement of the second set of left hand threads. The first set of left hand threads on the conduit will then be in the annular groove defined between the left and right hand threads of the coupling member. A standard length of a second conduit having external right hand threads thereon may then be matingly engaged with the right hand threads of the coupling member.

Abstract: A corrugated flexible thin copper tube filled with sodium has a resilient flexible core along the axis thereof so arranged that it will contract and expand to take up the force of thermal expansion and contraction of the sodium. Since the coefficients of expansion of the sodium and copper are different, the absorption of this differential in force by the core prevents rupture of the copper tube and the formation of voids and hot spots within the copper tube.

Abstract: A single pole molded case circuit breaker is constructed with an internal metal frame to which the contact operating mechanism is mounted. This mechanism includes a releaseable cradle which when latched permits the circuit breaker contacts to be closed. The cradle is a single element having spaced parallel walls, a latching extension on one of these walls and a kicker on the other wall. When the cradle is released or tripped the kicker is engageable with a toggle interposed between the contacts and the cradle for collapsing the toggle to assure contact opening. Integral formation on the walls provide a pivotal mounting for the toggle. A reset pin is loosely mounted between the parallel walls for low friction resetting of cradle.

Abstract: An elongated fitting, which forms a thread as it is screwed onto the end of a conduit, has an internally threaded tubular portion at one end which receives the conduit. A stem portion on the opposite end permits coupling of the fitting to external parts. An intermediate portion is provided for rotating the fitting relative to the conduit. A longitudinal slot axially extends along the wall of the tubular portion to permit visual inspection of the amount of conduit inserted in the fitting and for lowering the tightening torque required for forming the threads on the conduit.

Abstract: A single pressure sulfur hexafluoride circuit interrupter is contained in a bottle or elongated, cylindrical housing filled with gas under moderate pressure. The bottle contains arcing and main contacts arranged generally along the axis of the bottle and arranged to separate from one another in the vicinity of a pair of spaced, conductive rings fixed relative to one another, and which serve as arc runners. Each of the rings is connected in series with a respective coil which is wound on the axis of its respective ring and which encircles the cooperating contact and conductors therefor. The coils and the conductive rings create a magnetic field which spins an arc drawn between the spaced short-circuited rings through the sulfur hexafluoride gas, thereby to extinguish the arc.

Abstract: A single pressure sulfur hexafluoride circuit interrupter is contained in a bottle or elongated, cylindrical housing filled with gas under moderate pressure. The bottle contains arcing and main contacts arranged generally along the axis of the bottle and arranged to separate from one another in the vicinity of a pair of spaced, conductive rings fixed relative to one another, and which serve as arc runners. Each of the rings is connected in series with a respective coil which is wound on the axis of its respective ring and which encircles the cooperating contact and conductors therefor. The coils and the conductive rings create a magnetic field which spins an arc drawn between the spaced short-circuited rings through the sulfur hexafluoride gas, thereby to extinguish the arc.

Abstract: A mechanical interlock for circuit breakers using a depressible, push-button operating handle, wherein two circuit breakers are paired and at least two circuit breaker pairs are adjacent: the interlock comprises a molding placed on top of the casings of the circuit breakers and shiftable by depression of the handles of one circuit breaker pair to a position to block depression of the handles of the other circuit breaker pair; with a row of circuit breaker pairs, shifting of one interlock shifts all other interlocks for all other circuit breaker pairs.

Abstract: A coupling member for joining two generally coaxial tubular members, for example electrical conduits, fittings and the like, is disclosed. The coupling member includes an elongated sleeve having axially extending threads formed internally at one end thereof and an outwardly flared, deformable section at the end thereof opposite the threads. The deformable section has an inwardly directed lip for engaging an annular groove formed on the outside surface of one of the members that is to be coupled. The other member that is to be coupled is provided with external threads that are arranged to matingly engage the internal threads on the sleeve. Interface surfaces for temporarily securing the sleeve and the second one of the two members to be joined are provided so that the sleeve does not rotate while the first one of the two members is being engaged therewith.

Abstract: A molded case multi-pole circuit breaker is provided with a solid state trip unit constructed to automatically open the breaker responsive to predetermined fault current conditions. In addition, a bimetal actuated device sensitive to air temperature within the breaker housing is provided for automatically opening the breaker when air temperature within the housing exceeds a predetermined level.

Abstract: A rejector pin member is field installable between the spring-loaded clip jaws of a terminal clip receiving a terminal blade of a cartridge fuse. The rejector pin allows the terminal clip to only accept a notched terminal blade of a fuse having a relatively low current rating and rejects the unnotched terminal blade of a cartridge fuse having a relatively high current rating, to prevent formation of an overcurrent heating hazard in the circuit protected by the fuse.

Abstract: Contactors and housings therefor wherein the contactor is provided with blow-out coils brought into circuit by the arc; arc extinguishers; and fuses in series with the contacts; a closing and holding magnet for operating the contacts; anti-single-phasing operation to open the contacts in response to overload interruption by a fuse; the housings being of modular arrangement to form a uniform control center and being provided with racking means for inserting and removing the contactors with the door closed; and means for protecting the operator including the closing off of access to at least the line bus when the contactor is racked out and disabling the racking mechanism when the contactor contacts are closed.

Abstract: A molded case multi-pole circuit breaker is provided with a solid state trip unit having removable and replaceable rating plug. A mechanical interlock trips the circuit breaker when a cover portion thereof is opened. This cover portion must be opened to gain access to the rating plug. A mechanical lockout device is actuated when rating plug is removed to maintain the breaker tripped and to prevent resetting thereof until a rating plug is reinserted in the trip unit.

Abstract: A molded case multi-pole circuit breaker is provided with a removable and replaceable solid state trip unit constructed with all fault current detecting elements within a common housing. For each circuit breaker pole the trip unit includes an input and an output transformer feeding circuitry mounted on a board disposed within the common housing. The circuitry output is connected to operate a permanent magnet latch for release of a mechanical latch that normally holds the contact operating mechanism in a reset position.

Abstract: An attachment for apparatus that is arranged to cut threads on a tubular workpiece. The attachment includes a vertically oriented chute for delivering a stream of the tubular workpieces, by gravity, to a retractable pin on which the lowermost workpiece is supported. A reciprocating member is provided with spring biased jaws for gripping and removing the lowermost workpiece from the pin at the receiving station. The workpiece is moved into opposition with a plunger which transfers the unthreaded workpiece to the thread cutting apparatus. After the threads are cut, the plunger then retracts, together with the threaded workpiece, which is stripped therefrom by a second pair of spring biased jaws and carried away from the plunger so that the now threaded tubular workpiece may be discharged.

Abstract: A liquid-tight fitting is provided to connect generally non-compressible plastic conduit and electrical cable to a connection of some type. The fitting has a self-adjusting rigid plastic gland, which has a body portion with a relatively thin sleeve extending axially away from the body portion for encircling the conduit or cable. A nut threaded on the body of the fitting compresses the sleeve into sealing engagement with the conduit and fitting and to positively interconnect the conduit and connection to provide strain relief therewith.

Abstract: The arcing contact of a circuit breaker is made of a steel body which is plated with a copper flash and is then silver-plated. An arcing contact tip which makes actual contact to a cooperating arcing contact is made of a conventional silver-molybdenum alloy which is attached to the steel arcing contact as by brazing. The steel arcing contact is then connected in parallel with a conventional main contact which is made of high conductivity copper, or some other material having a conductivity which is high in comparison to the conductivity of steel. The steel arcing contact is used in either a butt-type contact configuration or in a jaw-type contact configuration.