Abstract: Overheating of the contacts and associated current-carrying parts of a vacuum type circuit breaker is prevented by fastening a U-shaped heat exchanger component of non-magnetic sheet metal to a protruding portion of the stem that is located at the top of the breaker bottle and is integral with the stationary contact. The U-shaped heat exchanger component is secured in inverted position on the stationary stem and the downwardly-extending skirts of the heat exchanger are slotted to provide a series of spaced ribs which form planar grid structures that allow ambient air to flow through the heat exchanger component and enhance its heat transfer characteristics.

Abstract: A molded case circuit breaker includes a highly integrated operating mechanism having an over-center, trip-free, pivot transfer toggle mechanism for opening and closing a pair of electrical contacts in response to overload and short circuit or fault current conditions. The toggle mechanism includes a pair of stationary, spaced apart links and a pair of movable, spaced apart toggle links. Each of the movable links includes an integrally formed, first or initial pivot point formed along its surface for engagement with a surface of one of the stationary links. Each of the stationary links includes a second pivot point formed along its surface for engagement by a surface of one of the movable links. The movable links are sequentially pivotably movable during a trip operation of the circuit breaker initially about the first pivot points and subsequently about the second pivot points.

Abstract: An enclosure structure for housing switchgear apparatus (such as circuit breakers) is fabricated from a pair of sheet metal panels that are held in precisely-spaced upstanding relationship by a plurality of metal cross-struts of U-shaped cross-section which mechanically interlock with apertured portions of the panels and are held in such position by triangular-shaped metal gussets which overlap and are bolted to adjacent portions of the cross-struts and panels. The cross-struts are provided with longitudinally protruding tangs at each end that are slip-fitted into and interlock with slot apertures in the panels. The width dimension of the finished enclosure structure is precisely controlled by positioning tabs on the ends of the cross-struts that are offset from the associated tangs and are drawn into abutting relationship with the inner surfaces of the respective panels when the structure is bolted together.

Abstract: A molded case circuit breaker includes a movable upper electrical contact member having an end portion with an arcuate cam surface formed thereon for engaging an exposed spherical surface of a spring-loaded ball that is disposed in a pocket provided in a rotatable cross-bar of the operating mechanism of the circuit breaker. A compression spring is also disposed in the pocket between the cross-bar and the ball to supply sufficient biasing force to the end portion of the movable upper electrical contact member to enable the upper electrical contact member to move in unison with the cross-bar during normal operation of the breaker. Upon the occurrence of a high level short circuit or fault current of sufficient magnitude, the upper electrical contact member rotates and the arcuate cam surface thereof moves against the exposed surface of the then stationary spring-loaded ball.

Abstract: A molded case circuit breaker includes a movable upper electrical contact carried by a contact member having an end portion with an arcuate cam surface formed thereon for engaging an outwardly projecting cam surface of a leaf spring. The leaf spring is secured to and disposed around an enlarged portion of a rotatable cross-bar of the operating mechanism of the circuit breaker. The leaf spring has an outwardly protruding cam surface and is mechanically configured to provide sufficient biasing force to the end portion of the movable upper electrical contact member to enable the upper electrical contact member and upper contact to move in unison with the cross-bar during normal operation of the breaker. Upon the occurrence of a high level short circuit or fault current of sufficient magnitude, the upper electrical contact rotate member and upper and the arcuate cam surface thereof is moved against the then stationary cam surface of the leaf spring.

Abstract: A molded case circuit breaker includes a movable lower electrical contact assembly having a formed stationary conductor member, a movable lower contact arm, a lower contact secured to the upper end of the movable lower contact arm for physically and electrically contacting separate upper electrical contacts, and a lower contact arm torsion spring. An integral longitudinal end of the stationary conductor member extends from the base of the circuit breaker to form an external terminal of the circuit breaker. The opposite longitudinal end of the stationary conductor member receives a rotatable pin fixedly secured to the movable lower contact arm for rotation therewith. The lower contact arm torsion spring has an elongated torsion spring arm disposed in contact with an elongated inclined cam surface located on the underside of the movable lower contact arm to bias the lower contact secured thereto into engagement with the upper electrical contact.

Abstract: A molded case circuit breaker includes an operating mechanism position indicator having a plurality of electrically insulating cards or strips disposed beneath an opening in the breaker cover about a manually engageable handle of the circuit breaker for movement in response to movements of the handle along the cover opening. A first one of the cards includes a pair of spaced apart, laterally aligned red markings for providing an externally visually discernible indication that the operating mechanism of the circuit breaker is in its CLOSED position. The first card also includes a pair of spaced apart, laterally aligned white markings for providing an externally visually discernible indication that the operating mechanism of the circuit breaker is in its TRIPPED position. The second card is positioned beneath the first card and is of a substantially greater length than the first card.

Abstract: A molded case circuit breaker includes a highly integrated operating mechanism having an over-center toggle mechanism for opening and closing a pair of separable electrical contacts. A pivotable, one-piece cradle coupled to the breaker handle includes a cradle latch surface for latching with a trip arm of a trip mechanism, a contact stop surface for limiting the movement of one of said electrical contacts and an arcuate cam surface for engaging a cradle cam pin during a reset operation. The arcuate cam surface of the cradle is contoured to enable the resetting of the operating mechanism after a trip operation by applying a relatively low, substantially constant reset force to the breaker handle.

Abstract: A molded case circuit breaker includes a movable upper electrical contact carried by a movable arm having an end portion with an arcuate cam surface formed thereon for engaging an outwardly projecting cam surface of a spring-loaded clip that is disposed in a recess formed in a rotatable cross-bar of an operating mechanism of the circuit breaker. At least one compression spring is retained within the recess between the cross-bar and the spring clip. The spring clip is configured to transfer sufficient biasing force to the end portion of the movable upper electrical contact end to enable the upper electrical contact arm to move in unison with the cross-bar when the circuit breaker is tripped. Upon the occurrence of a high level short circuit or fault current of sufficient magnitude, the upper electrical contact arm and contact rotate independently of the cross-bar and the arcuate cam surface of the arm is moved against the then stationary spring clip cam surface.

Abstract: A molded case circuit breaker includes a new and improved calibration adjusting means for a bimetal in a trip mechanism. The trip mechanism also includes a bimetal having a portion movable in response to predetermined overload conditions, an intermediate control lever for adjusting the spatial disposition of the movable portion of the bimetal with respect to a trip bar of the trip mechanism and a rotatable adjustment means for adjusting the spatial disposition of the intermediate control lever in the circuit breaker. By rotating the adjustment means, the distance between the movable portion of the bimetal and the trip bar can be precisely adjusted via the intermediate control lever. The intermediate control lever is coupled to a relatively stationary portion of the bimetal thereby enabling such adjustment without applying undue stress to the movable portion of the bimetal.

Abstract: The gap distance separating the contacts of a low-voltage circuit breaker in the tripped position is increased by utilizing resilient stop means which is located at the bottom wall of the breaker housing rather than at the top wall (or on the handle of the breaker) in accordance with prior art practice. The movable contact arm is pivotally mounted and structured to strike the stop means as the contacts are separated and being blown open during short circuit conditions and, after the circuit breaker is tripped, the collapsed toggle assembly of the operating mechanism shifts the movable contact arm away from the stop means and allows the arm to move an additional distance away from the fixed contact and thus increase the gap distance between the opened contacts.

Abstract: The kinetic energy generated by the rapidly moving contact and coupled operating mechanism of a tripped circuit breaker or similar apparatus is dissipated by a compressible shock-absorbing assembly comprising a loose stack of metal plates and interposed springs which is mounted on a stationary part of the breaker and is struck by a lever fastened to the main operating shaft of the breaker operating mechanism. The metal plates are movable toward and away from one another due to the resiliency of the springs and the resulting multiple impacts between the plates and advancing striker lever produces a momentum exchange phenomenon which quickly dissipates the kinetic energy and brings the breaker operating mechanism and movable contact to a smooth stop. The compressible multiple-impact assembly provides a compact shock absorbing means that is especially adapted for use in medium voltage circuit breakers (5 to 35 KV rating) of various types which is not only durable and efficient but very inexpensive and reliable.

Abstract: An arc chute assembly for a circuit breaker or similar device comprising a series of metallic arc chute plates that are locked in stacked spaced-apart relationship between a pair of insulative side panels by elongated key members of non-conductive material that are wedged between the flat surfaces of the side panels and notched portions of pairs of T-shaped tabs which extend from each side edge of the respective plates. The tabs interlockingly engage a series of laterally-extending slot openings in the side panels in such a manner that the key members are in press-fitted engagement with only one of the tabs in each pair of tabs.

Abstract: A terminal assembly for connecting a line cable to the bus conductor of a circuit interrupter or similar device by means of a locking screw that extends through the top wall of a metal lug component and clamps the inserted ends of the cable and bus conductor in overlapping relationship with each other and positive electrical contact with the bottom wall of the lug component. The bus conductor is held in slip-fitted interlocked position at the bottom of the lug component opening by the coaction of a pair of undercut grooves in the side walls of the lug component that accommodate the side edges of the bus conductor and cooperates with a coupling screw which extends through the bottom wall of the lug component and engages an unthreaded hole in the inserted end of the bus conductor.

Abstract: The surface of a metal article which is exposed to the atmosphere and abrasion during normal use of the article is protected from scratches and/or corrosion during such use by a thin transparent abrasion-resistant film of an inert non-metallic material such as SiO.sub.2, SiC, Si.sub.3 N.sub.4, TiO.sub.2, MgO, Al.sub.2 O.sub.3, Ta.sub.2 O.sub.5, Nb.sub.2 O.sub.5, GeO.sub.2, spinel and selected colorless glass compositions. The protective film is preferably deposited by RF-sputtering techniques and undesirable coloration of the article by optical interference effects from incident light rays is avoided by properly correlating the film thickness with the refractive index of the particular material used to form the film. The invention permits the use of thinner gold plating on such items as articles of expensive jewelry and bracelets and cases for fine wristwatches without detracting from the quality, durability or appearance of the merchandise.

Abstract: The surface of a metal article which is exposed to the atmosphere and abrasion during normal use of the article is protected from scratches and/or corrosion during such use by a thin transparent abrasion-resistant film of an inert non-metallic material such as SiO.sub.2, SiC, Si.sub.3 N.sub.4, TiO.sub.2, MgO, Al.sub.2 O.sub.3, Ta.sub.2 O.sub.5, Nb.sub.2 O.sub.5, GeO.sub.2, spinel and selected colorless glass compositions. The protective film is preferably deposited by RF-sputtering techniques and undesirable coloration of the article by optical interference effects from incident light rays is avoided by properly correlating the film thickness with the refractive index of the particular material used to form the film. The invention permits the use of thinner gold plating on such items as articles of expensive jewelry and bracelets and cases for fine wristwatches without detracting from the quality, durability or appearance of the merchandise.

Abstract: Sporadic malfunctions of the closing resistor mechanism employed in a power circuit breaker to connect a resistor in parallel with the breaker contacts (prior to closing of such contacts) is prevented by providing an improved control and actuating means for the resistor mechanism which insures that the latter is reliably reset for use each time the breaker is operated. A self-adjustable component, such as a spring-loaded link, is inserted in the tie-rod structure which couples the breaker operating lever to the closing resistor operating lever. The resulting "elastic" coupling action automatically positions the levers in the proper relationship for resetting of the resistor mechanism despite small variations in the complete-open position of the breaker operating mechanism and linkage system.

Abstract: The surface of a metal article which is exposed to the atmosphere and abrasion during normal use of the article is protected from scratches and/or corrosion during such use by a thin transparent abrasion-resistant film of an inert non-metallic material such as SiO.sub.2, SiC, Si.sub.3 N.sub.4, TiO.sub.2, MgO, Al.sub.2 O.sub.3, Ta.sub.2 O.sub.5, Nb.sub.2 O.sub.5, GeO.sub.2, spinel and selected colorless glass compositions. The protective film is preferably deposited by RF-sputtering techniques and undesirable coloration of the article by optical interference effects from incident light rays is avoided by properly correlating the film thickness with the refractive index of the particular material used to form the film. The invention permits the use of thinner gold plating on such items as articles of expensive jewelry and bracelets and cases for fine wristwatches without detracting from the quality, durability or appearance of the merchandise.

Abstract: Restoration of a gas-insulated type circuit breaker having a puffer assembly to "contact-closed" condition is achieved in a positive and reliable manner by providing the puffer cylinder with one or more apertures that relieve the back-pressure created by the rapid expansion of the puffer chamber during the contact-closing stroke of the arc-interrupter unit. The pressure-relieving aperture or apertures are so shaped and located that they are automatically opened and closed at the proper times by the movement of the puffer cylinder and movable contact relative to the stationary piston component. The gas-compression and puffer functions during the contact-opening operation and subsequent relief of the back-pressure condition during the contact-closing operation of the circuit breaker are thus provided without the need of check valves heretofore employed in the piston head to control the flow of the insulating gas into and out of the puffer chamber when the breaker is actuated through a full cycle of operations.

Abstract: The convoluted fluorescent lamp component of a compact lamp unit is mechanically and electrically coupled to a base module by a plate-like mounting member which is secured to the module in suspended fashion and has socket means which permit the lamp component and associated energizing-circuit components to be plugged into and removed from the module. The mounting member is structured and oriented to also provide a peripheral air passageway which, in conjunction with vent openings in the module and in a protective cover which is secured to the module, allows air to flow freely through the operating unit and convection-cool the fluorescent lamp. The lamp unit can accordingly be operated at high power loadings without overheating and can also be easily relamped and provided with new circuit components (such as a ballast and/or a starter) to prolong its useful life.