Patents Assigned to McGraw-Edison Company
  • Plaster frame for recessed lighting
    Patent number: 4408262
    Abstract: A plaster frame for mounting a lighting fixture in recessed fashion in a ceiling comprises a main body portion including a rectangular, planar member defining an aperture therein, the aperture being similarly dimensioned to the ceiling aperture in which the lighting fixture is to be mounted. Hanger bar brackets are integrally formed with the planar member at breakaway junctions along opposite, first sides of the planar member. The hanger bar brackets are adapted to receive hanger bars for mounting the plaster frame between spaced joists supporting the ceiling. Each hanger bar bracket is removable from the planar member by bending at the breakaway junctions. The hanger bar brackets are reattachable to the planar member along opposite, second sides thereof by means of bendable, spaced tabs formed on the brackets receivable in similarly spaced apertures defined in the planar member.
    Type: Grant
    Filed: June 1, 1982
    Date of Patent: October 4, 1983
    Assignee: McGraw-Edison Company
    Inventor: Raymond J. Kusmer
  • Overcurrent relay circuit
    Patent number: 4393431
    Abstract: An overcurrent relay circuit has a power supply developed from a test signal representative of the current in the line being monitored. The power supply is a Zener diode and capacitor arrangement connected in series with the load or test resistor. A variable time-current characteristic circuit (or timing plug) is based upon a variable effective capacitance circuit in which the timing capacitor and resistor currents are isolated from, but dependent upon, one another.
    Type: Grant
    Filed: April 23, 1980
    Date of Patent: July 12, 1983
    Assignee: McGraw-Edison Company
    Inventor: Clyde Gilker
  • In-line fuse holder for miniature plug-in fuse
    Patent number: 4391485
    Abstract: An in-line fuse holder capable of handling currents as high as 30 amps, adapted to accept miniature, relatively flat, plug-in fuses which have a pair of flat terminals and a fuse link visibly retained within a relatively flat plastic case. The in-line fuse holder has a relatively rigid casing in which a pair of generally U shaped contact clip assemblies are mounted for receiving the flat terminals of the plug-in fuse. The contact clips are of two piece construction with an inner clip of highly conductive material and an outer clip of highly resilient material. The outer clip fits over the inner clip to force the inner clip into low resistance contact with the fuse terminals.
    Type: Grant
    Filed: January 9, 1981
    Date of Patent: July 5, 1983
    Assignee: McGraw-Edison Company
    Inventor: Angelo Urani
  • Current limiting fuse
    Patent number: 4388603
    Abstract: A current limiting fuse has a main fusible element and an auxiliary fusible element each helically wound over an insulative support member. Each end of the auxiliary element is connected to conductive metal clips or electrodes in which blocks of metal oxide varistor material are fixedly secured and placed in contact with the main fusible element. Subsequent to the initial burn back of the main fusible element, the metal oxide varistors precisely initiate electrical arcs between the terminal clips at the ends of the auxiliary fusible element and the main element at points adjacent to these terminal clips. The presence of these arcs quickly sever the main element or elements at these points thereby producing additional burnback areas in the main fusible element or elements.
    Type: Grant
    Filed: May 15, 1981
    Date of Patent: June 14, 1983
    Assignee: McGraw-Edison Company
    Inventors: Stephen P. Hassler, Theodore O. Sokoly
  • Fault responsive protective device
    Patent number: 4386384
    Abstract: An improvement to fault responsive protective devices, which employ timing capacitors, is provided by controlling the voltage of the timing capacitor by clamping it to a value slightly in excess of the voltage on a master timing capacitor. This allows the master timing capacitor to inhibit the operation of the improved fault responsive device without affecting the input to the timing capacitor. The inherent time constant produced by the timing capacitor is not altered. However, by clamping the voltage level of the timing capacitor only under appropriate conditions, the time current characteristic of the improved fault responsive protective device is altered only when those conditions occur which make it desirable to lengthen the interval before the fault responsive protective device responds to a fault.
    Type: Grant
    Filed: December 15, 1981
    Date of Patent: May 31, 1983
    Assignee: McGraw-Edison Company
    Inventor: Richard J. Moran
  • Operating mechanism for a fluid blast circuit interrupter
    Patent number: 4383151
    Abstract: An operating mechanism for a fluid blast circuit interrupter which is actuated by a single drive shaft and includes a toggle linkage for opening and closing the breaker contacts, and a cam and rachet assembly for opening and closing a gas supply valve. Upon initiation of an opening or closing operation, the cam is coupled to the drive shaft and rotated to open a normally closed, spring loaded, gas valve before the interrupter contacts are opened or closed, and to charge a cam return spring. After the interrupter contacts are fully opened or closed, the cam is disengaged from the drive shaft and returned to its neutral position by its return spring to allow the gas valve to reclose.
    Type: Grant
    Filed: May 12, 1980
    Date of Patent: May 10, 1983
    Assignee: McGraw-Edison Company
    Inventors: Nils Holmgren, Charles J. Knotek
  • Heat limiters and method of manufacture
    Patent number: 4383236
    Abstract: A circuit interrupting device responsive to externally generated heat and method of manufacture of such device. The device includes a pair of spaced, coaxially aligned leads each entering a thermally conductive housing from an opposite end. The inserted ends of the coaxially aligned leads are bridged by a conductive member comprising the tail of a conical spring which surrounds one of the leads and is secured at a corresponding end of the housing. The circuit-completing spring tail is secured by fusible material to the inserted ends of each of the spaced-apart leads. In a normal, closed circuit condition, the spring is under tension. Upon heating, the fusible material softens, allowing the spring tail to break away from the inserted ends of the spaced-apart leads, the retracting force of the conical spring, pulling the spring tail from the other one of the leads to open the circuit.
    Type: Grant
    Filed: December 28, 1981
    Date of Patent: May 10, 1983
    Assignee: McGraw-Edison Company
    Inventors: Angelo Urani, Aldino J. Gaia
  • Compound reflector for luminaire
    Patent number: 4379322
    Abstract: An outdoor luminaire having a reflector adapted to provide uniform illumination of a relatively large, generally level surface. The reflector is comprised of a pair of side segments and contiguous concave top and bottom segments surrounding a light center. The top segment includes three cylindrical portions which are circular in section, the portion adjacent the top edge having its circular center well in front of the light center, while the other two circular cylindrical portions have their centers behind the light center. The bottom segment includes a transient portion and a cylindrical portion which is parabolic in section. The parabolic cylindrical portion is adjacent the bottom edge and has its foci at the light center. The side segments are tilted to reflect light from the light center directly out of the luminaire.
    Type: Grant
    Filed: March 27, 1981
    Date of Patent: April 5, 1983
    Assignee: McGraw-Edison Company
    Inventor: James P. Kelly
  • Multiple element current limiting fuse
    Patent number: 4375630
    Abstract: A multiple element current limiting fuse has a plurality of tube fuses soldered at opposite ends to a pair of metallic end bells having blade-like terminals for connection to busbars of an external electrical circuit. Fasteners having the general dimensions of the tube fuses are also mounted between the end bells and connectors, such as, studs or rivets are formed on ferrules at opposite ends of the fasteners to mechanically couple the fasteners to the end bells and preserve the spacing between the end bells even when the fuse is subjected to tensile forces and elevated temperatures efficient to soften the solder. The use of a hollow ceramic body and hollow connectors at the ends of the fasteners permits the passage of coolant through the fasteners for cooling the multiple element fuse.
    Type: Grant
    Filed: April 1, 1981
    Date of Patent: March 1, 1983
    Assignee: McGraw-Edison Company
    Inventor: Aldino J. Gaia
  • Multiple element current limiting fuse
    Patent number: 4369422
    Abstract: A multiple element fuse has a pair of end bells with terminals for connection to spaced apart busbars of an external electrical circuit. A plurality of tube fuses are mechanically fastened and soldered at opposite ends thereof to the end bells. The tube fuses have insulative tubular bodies with metallic ferrules attached at each end. The ferrules which are received in cavities defined in the end bells, include hollow studs for receipt in countersunk holes also formed in the end bells. The studs are flared and/or receive expansion plugs to mechanically attach the tube fuses to the end bells, thereby to preserve the spacing between the end bells even when the fuse is subjected to tensile forces created by the busbars and sufficient heat to melt the solder during fuse clearing.
    Type: Grant
    Filed: April 1, 1981
    Date of Patent: January 18, 1983
    Assignee: McGraw-Edison Company
    Inventors: John F. Rasmussen, Jayant S. Hemmady
  • High speed floor polisher
    Patent number: 4358868
    Abstract: A high speed vertical axis floor treating machine for polishing, brushing or scrubbing a floor includes a frame, a drive motor on the frame for rotating a floor treating element, a control handle pivoted to the frame, and a pair of ground engaging wheels mounted on an axle. The frame is resiliently supported on the axle to permit edging of the floor treating element. An adjustment rod engaging the axle raises and lowers the frame on the axle. The drive motor is mounted rearwardly of the axle to counterbalance the weight of the floor treating element about the axle.
    Type: Grant
    Filed: May 12, 1980
    Date of Patent: November 16, 1982
    Assignee: McGraw-Edison Company
    Inventor: Floyd L. Cook, Jr.
  • Power cord storage device
    Patent number: 4354650
    Abstract: A power cord storage device for electrically powered apparatus, such as a vacuum cleaner having a control handle, includes a first pin, an arm rotatably supported on the handle and including a hub portion defining an L-shaped slot within which the pin extends, another arm secured to another leg of the handle and being rotatable to a first position so that the pin may be positioned in one leg of the slot and the power cord may be wrapped around the arms. The hub may be shifted to place the pin in the other leg of the slot to release the power cord.
    Type: Grant
    Filed: March 18, 1981
    Date of Patent: October 19, 1982
    Assignee: McGraw-Edison Company
    Inventor: Dale E. Lowder
  • Electrical apparatus having an improved dielectric system
    Patent number: 4355346
    Abstract: An electrical apparatus, such as a capacitor, having an improved dielectric system. The capacitor includes alternate layers of metal foil and dielectric material which is impregnated with 1,1-bis(3,4-dimethylphenyl)ethane. The capacitor has improved corona characteristics and low dielectric losses. The liquid dielectric is biodegradable and environmentally acceptable.
    Type: Grant
    Filed: October 21, 1980
    Date of Patent: October 19, 1982
    Assignee: McGraw-Edison Company
    Inventors: Gary A. Gauger, Marco J. Mason
  • Backup trip circuit for a circuit breaker
    Patent number: 4352138
    Abstract: A backup trip circuit is provided for an electronically controlled recloser or circuit breaker which requires a constant voltage direct current supply for its normal tripping circuit. Whenever the normal DC supply voltage drops below the minimum level, a capacitor is coupled to and charged by, the distribution line current. Then, whenever the line current exceeds a selected magnitude for a selected period of time, the capacitor is discharged through the trip coil of the breaker to open this distribution line.
    Type: Grant
    Filed: November 25, 1980
    Date of Patent: September 28, 1982
    Assignee: McGraw-Edison Company
    Inventor: Clyde Gilker
  • Current limiting fuse having transverse parallel weak spots
    Patent number: 4349802
    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.
    Type: Grant
    Filed: January 8, 1981
    Date of Patent: September 14, 1982
    Assignee: McGraw-Edison Company
    Inventor: Aldino J. Gaia
  • High efficiency lighting units and systems using same
    Patent number: 4344111
    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.
    Type: Grant
    Filed: August 8, 1980
    Date of Patent: August 10, 1982
    Assignee: McGraw-Edison Company
    Inventors: Alan J. Ruud, Ian Lewin
  • Load break switch
    Patent number: 4343030
    Abstract: A compact load break switch having at least one vacuum interrupter connected between two terminals carried by respective insulating bushings through a current exchange assembly. The vacuum interrupter is disposed within one of the insulating bushings, and a current exchange insulating housing having portions which extend telescopically into both insulating bushings, provides adequate creepage distance through air from the vacuum interrupter and the current exchange assembly to a grounded housing for the load break switch. Also, a current transformer is disposed about the insulating housing to provide remote indication of the flow of fault current through the current exchange assembly.
    Type: Grant
    Filed: February 4, 1981
    Date of Patent: August 3, 1982
    Assignee: McGraw-Edison Company
    Inventors: K. Henry Date, Ronald Wainio
  • Floor polisher support
    Patent number: 4337546
    Abstract: A vertical axis floor treating machine and support attachment are disclosed. The machine includes a housing to which the attachment is clamped. The attachment includes a frame having a slide thereon. The frame and slide define an aperture for receipt of the housing. Clamps secure the attachment to the housing.
    Type: Grant
    Filed: April 25, 1980
    Date of Patent: July 6, 1982
    Assignee: McGraw-Edison Company
    Inventor: Paul E. Phillips
  • Accessory solution tank for vacuum cleaner
    Patent number: D266613
    Type: Grant
    Filed: December 18, 1980
    Date of Patent: October 19, 1982
    Assignee: McGraw-Edison Company
    Inventor: Dale E. Lowder
  • Floor polisher
    Patent number: D269557
    Type: Grant
    Filed: March 24, 1980
    Date of Patent: June 28, 1983
    Assignee: McGraw-Edison Company
    Inventor: Floyd L. Cook, Jr.