Abstract: An air-operated switching device includes first and second spaced supports on which an armature is mounted. The armature includes a resilient blade fixedly mounted at a first end on the first support and for sliding movement with respect to the second support. A resilient contact finger extends from the slidably supported end of the armature and includes a free end having a contact thereon. A fixed contact is positioned in alignment with the contact of the finger. An air-operated actuator applies pressure to the blade causing it to flex with the one end of the blade moving slidably over the second support, thereby causing the finger contact to be moved into engagement with the fixed contact with a wiping motion.

Abstract: A current limiting fuse includes a fusible strip having semi-circular apertures formed therein, centrally disposed between the longitudinal edges of the strip. The diametric edges of the apertures lie transverse to the longitudinal edges of the fusible strip. The curved edges of the apertures are disposed in opposing relationship. Electrical weak spots which are less conductive than the remaining areas of the strip are defined between the semi-circular apertures and the longitudinal edges of the fusible strip. Semi-circular cut-outs may be included along the longitudinal edges of the fusible strip adjacent the centrally disposed semi-circular apertures to define the electrical weak spots between the cut-outs and centrally disposed apertures.

Abstract: A fuse assembly for a miniature plug-in fuse is provided with a pair of parallel spaced-apart conductive legs, each having plug-in members at one end. A fuse link of generally constant cross sectional area, integrally formed with the conductive legs, extends therebetween to form a fuse assembly of substantially planar construction. The fuse link is provided with one or more transverse offsets, each forming a weak spot.

Abstract: A lighting unit comprising a lamp and a reflector provides high intensity, high efficiency, even illumination over an area of particular shape and size and has a cut-off angle which enables a person to approach close to the lighting unit without seeing the lamp or its reflection. The reflector comprises at least two spaced apart curved reflector surfaces which join each other along an edge line in a plane behind and spaced from the lamp. Points on the curve line of each reflector surface are spaced progressively farther away from the lamp than the edge line. Some points on the curve are located on the side of the plane remote from the lamp. The lighting unit, which may employ reflector surfaces in addition to those above mentioned, may be employed in systems wherein it projects light upwardly for downward reflection from a ceiling or projects light downwardly directly onto a work surface.

Abstract: A rechargeable flashlight fits into and draws recharging power from an automotive type cigar lighter socket. A thermally controlled charging circuit within the flashlight adjusts the charging rate according to the ambient temperature. When the flashlight is withdrawn from the cigar lighter socket, it is illuminated; when it is replaced it is extinguished. Alternatively, the flashlight may be manually illuminated or extinguished outside the charging socket.

Abstract: Compact bodies for use as contacts in vacuum current interrupters, plasma devices and the like are formed by a vacuum hot press fabrication of suitable powder material. The contacts which may be formed as a button or ring, are operable under high current arcing conditions. The powder material is mixed and placed between a pair of rams in a floating die cavity maintained in an inert atmosphere and is placed in a vacuum chamber. A vacuum is created without pressurizing the powder material. The powder material is heated to below its melting temperature for degassing. The die cavity preferably includes special outgassing ports. The rams are pressurized and the powder material reaches a sintering temperature and a vacuum of 3.times.10.sup.-6 torr. A uniform composition compact body essentially devoid of trapped gas and particularly suitable for use as a high current interrupting contact in an arcing environment results.

Abstract: A dual element, time delay fuse with greater blowing time accuracy and improved operating characteristics wherein any bridging of the circuit opening air gaps by molten alloy is effectively precluded during operation of the fuse, especially operation initiated by small protracted overloads. This is accomplished with a fuse element assembly comprising a series connection of a short circuit member, a central absorber member and a heater element member, the central absorber member held to the short circuit member and heater element member by masses of fusing alloy on each of its ends, which masses of fusing alloy are prevented from combining in fabrication and circuit opening operation by flow restricting apertures located near each end of the absorber member.

Abstract: A power class fuse comprises an insulative canister having a female load break contact at a closed end of the canister and a male load break contact, coupled electrically to a fuse element. The male load break contact is inserted into the canister for engagement with the female load break contact to complete a circuit through the fuse element. An arc gas control device including a pair of spaced parallel plates each having apertures formed therethrough and filter material sandwiched between the plates, is mounted on the male load break contact. The arc gas control device forms a partition in the canister upon insertion of the male load break contact thereinto. Arc gas generated upon engagement of the male and female load break contacts passes through the control device into the canister interior surrounding the fuse element to reduce back pressure in the canister, while metallic particles and other contaminants which could produce flashovers within the canister, are trapped in the filter material.

Abstract: A secondary valve arrester for protection of secondary electrical systems, comprises a housing having a lid and base portion, the latter of which includes a plurality of compartments each of which is dimensioned to receive a valve block and spark gap assembly or a varistor assembly; the number of said assemblies included in the arrester corresponding to the number of phases protected in the system. Each said assembly includes connecting electrodes of similar construction, each connecting electrode having two offset male terminals and one offset female terminal for connection to externally connected lead wires or other connecting electrodes. The housing lid includes first and second rib sets for extension into the base portion to retain the said assemblies in a tightly stacked condition in respective compartments.

Abstract: A thermal protective device for interrupting current to the lamp circuit of an electrical lighting fixture when the temperature at a preselected location in the fixture reaches a predetermined level, comprises a receptacle including a pair of female terminals coupled electrically to the lamp circuit. A normally open switch having a movable contact arm with a hooked end portion is coupled to one of the terminals to maintain the lamp circuit normally open. A plug adapted for joinder with the receptacle includes a pair of male terminals arranged for receipt by the female terminals of the receptacle. A thermal protector included in the plug is operable from a closed to an open condition when the temperature reaches the aforesaid predetermined level. The thermal protector is connected electrically across the male terminals. An actuator and latch arm extending from the plug is received in the receptacle upon joinder of the receptacle and plug.

Abstract: A recrystallized copper billet in excess of one and one-half inches in diameter is formed as an essentially single-grain or crystal copper. A high conductivity, oxygen-free copper billet is subjected to mechanical surface cleaning and to a "bright dip" bath to chemically clean the surface. The copper billet is located in a similar sized graphite crucible and induction-heated in a vacuum chamber to a modest temperature for outgassing of said crucible. The heating is increased to melt the copper and then is reduced in steps to produce a copper equilibrium temperature about seventeen degrees centigrade above the melting point of the copper. A slow non-directional and natural cooling at the rate of about three to fifteen degrees per hour is created until total solidification and recrystallization occurs.

Abstract: A current limiting fuse construction including a fuse element extending between electrically conductive terminals carries a body of arc-quenching filler material within a hollow casing of electrical insulating material. The filler material includes a first portion of arc quenching aluminum sulfate mixed with calcium sulfate binder, and second portion of arc quenching silica sand arranged in stratified layers, with the aluminum sulfate layer being positioned closest to a weak spot of the fuse element, and the layer of silica sand being positioned closer to an end cap of the fuse casing.

Abstract: A pan for a ceiling mounted light fixture includes a saucer-like canopy defining a mounting hole for receipt of a fastener to secure the light fixture to a ceiling support surface. A first layer of insulative material is received between the canopy and the ceiling surface. Descending arms spaced about the periphery of the canopy join the canopy to a housing portion which is suspended therefrom. The housing portion includes concentric outer and inner walls, the latter of which has an inwardly extending lip or ledge defining a shelf to support a second layer of insulative material disposed between the canopy and shelf. Electrical sockets for receiving incandescent lamps are mounted on the lower wall of the shelf and a glass or the like shade is received thereover and secured by screws extending through the outer wall of the housing portion. The double layers of insulative material serve as barriers to prevent damage to the ceiling surface from heat generated by the incandescent lamps of the light fixture.

Abstract: The method of manufacturing metal oxide varistors wherein pressed blocks of selected mixtures of metal oxide powders and additives are joined to form a single varistor unit by vertically stacking and firing the blocks at a high temperature. Sintering of these stacked blocks during the firing cycle results in a strong mechanical and electrical bond between the adjacent blocks in the stack.

Abstract: An arrangement for the recessed mounting of an enclosed light fixture housing having an open end with a flange formed about the periphery thereof in an aperture defined in a planar member, such as a ceiling, includes a slotted aperture defined in the side wall of the housing with ratchet teeth formed therealong adjacent the slotted aperture, a support frame mounted behind the ceiling and including an aperture dimensioned similarily to and aligned with the aperture in the ceiling and a resilient mounting clip attached to the support frame and extending into the aperture. The free end of the mounting clip is dimensioned for receipt in the slotted aperture of the housing side wall upon insertion of the housing into the aligned ceiling and support frame apertures. Shoulder portions adjacent the free end of the clip engage the ratchet teeth to removably lock the housing in position in the ceiling.