Patents Assigned to Littelfuse, Inc.
  • Patent number: 5663861
    Abstract: A circuit protection device including a pair of terminals to be electrically connected into an electrical circuit, a pair of spaced current-carrying extensions of the terminals, and an initially low resistance current limiting element extending between the current-carrying extensions. The current-limiting element includes flexible conductive current-feeding arms having inner and outer end portions, the inner end portions thereof being electrically connected to the current-carrying extensions of the terminals. The outer end portions of the current-feeding arms are cantilevered and flexible relative to the inner end portions. The device further preferably includes a PTC current-limiting element sandwiched between the flexible outer end portions of the current-feeding arms.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: September 2, 1997
    Assignee: Littelfuse, Inc.
    Inventors: Nagi Reddi Kanamatha Reddy, Robert Swensen, Thomas F. Draho
  • Patent number: 5596306
    Abstract: Fuses and a subassembly component for fuses. The fuse includes an insulating housing, a short circuit fusible element, and an arc barrier-forming body. The arc barrier-forming body is fitted around, and intimately surrounds a portion of the short-circuit fusible element. The arc barrier-forming body is formed from a silicone rubber sealant which is free flowing at room temperature but upon exposure to air increases in viscosity until it essentially becomes a solid. The arc barrier-forming body provides protection against "burn-back" within the fuse.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: January 21, 1997
    Assignee: Littelfuse, Inc.
    Inventors: Joseph W. Kowalik, Heraclio R. Gomez
  • Patent number: 5581225
    Abstract: A female fuse assembly includes a female fuse and a housing. The female fuse includes a first and a second female terminal portion each having a face portion which includes a first end, a second end, a first side, and a second side, includes a first clamping arm and a second clamping arm, includes a first bracing arm and a second bracing arm, and includes a fuse link having a first terminal extension and a second terminal extension, and having a skived region for controlling the resistance between the first and second female terminal portions. The fuse link further includes a first terminal bend and a second terminal bend. The first terminal bend is positioned substantially toward the second end of the first face portion, or vice versa, and the second terminal bend is positioned substantially toward the first end of the second face portion, or vice versa, for increasing the length of the fuse link.
    Type: Grant
    Filed: April 20, 1995
    Date of Patent: December 3, 1996
    Assignee: Littelfuse, Inc.
    Inventors: Seibang Oh, James J. Beckert, Theodore W. Humphrey, William P. Hendrickson
  • Patent number: 5552757
    Abstract: A thin film surface-mount fuse having two material subassemblies. The first subassembly includes a fusible link, its supporting substrate and terminal pads. The second subassembly includes a protective layer which overlies the fusible link so as to provide protection from impacts and oxidation. The protective layer is preferably made of a polymeric material. The most preferred polymeric material is a polycarbonate adhesive. In addition, the most preferred supporting substrate is an FR-4 epoxy or a polyimide.
    Type: Grant
    Filed: May 27, 1994
    Date of Patent: September 3, 1996
    Assignee: Littelfuse, Inc.
    Inventors: Vladimir Blecha, Katherine M. McGuire, Andrew J. Neuhalfen, Daniel B. Onken
  • Patent number: 5345210
    Abstract: A time delay fuse and various subassembly components for that time delay fuse. The fuse includes a housing made of an insulating material. The housing encloses a short-circuit fusible element, preferably a copper or copper alloy strip having a plurality of slots. The housing also encloses one or more rigid meltable fusible elements, preferably a plurality of solder bars. A body of resilient, compressible insulating material has at least one passageway through which each of the time delay fusible elements extends. When the rigid meltable fusible elements melt, the circuit through the fuse opens. In addition, the passageway which surrounded the rigid meltable fusible elements collapses upon its melting. This provides protection against "arc-back.
    Type: Grant
    Filed: July 19, 1993
    Date of Patent: September 6, 1994
    Assignee: Littelfuse, Inc.
    Inventors: Robert G. Swensen, Joseph W. Kowalik
  • Patent number: 5293147
    Abstract: A fuse for handling normal load currents substantially in excess of about 80 amps, the fuse comprising a metal portion formed of an integral piece of metal having outermost, spaced terminal-forming portions with bolt-anchoring holes therein and a fuse link-forming intermediate portion between the terminal-forming portions. The terminal-forming portions of the metal piece has a rectangular configuration having inner margins spaced from one another. The fuse link-forming portion of the metal piece has an S-shape with one face thereof being co-planar with one of the faces of the terminal-forming portions thereof. The thickness of the S-shaped fuse link is only a fraction of the thickness of the terminal thickness and has outermost legs respectively extending from the opposite sides of the innermost margins of the terminal-forming portions of the metal piece and a central link interconnecting the outermost legs.
    Type: Grant
    Filed: March 17, 1993
    Date of Patent: March 8, 1994
    Assignee: Littelfuse, Inc.
    Inventors: Seibang Oh, Robert Madland
  • Patent number: 5244418
    Abstract: A method of mass producing plug-in diode units includes the steps of punching areas of metal from a sheet metal body and forming the remaining areas of the body to leave longitudinally spaced, confronting pairs of laterally extending terminal blades having plug-in terminal end portions extending in different planes and opposite diode-mounting end portions in the same plane connected by webs or links to the rest of the sheet metal body. Diode elements are then soldered or welded between the diode-mounting end portions of each pair of terminal blades, and an insulating housing is molded around the diode-mounting end portions of each pair of terminal blades and the diode element secured thereto. The connecting links of each pair of terminal blades then are severed, leaving exposed severed portions of the connecting links which form accessible test points for testing the continuity of the diode element within each housing even after the terminal blades are plugged into a connector block.
    Type: Grant
    Filed: August 25, 1992
    Date of Patent: September 14, 1993
    Assignee: Littelfuse, Inc.
    Inventor: Arnold E. Gurley
  • Patent number: 5245308
    Abstract: A Class L fuse comprises a pair of conductive elements at the opposite ends of the fuse. A fusible element is secured to and makes electrical contact with each of the conductive elements. A generally cylindrical housing encloses the fusible element. Finally, an insulating, free-flowing arc barrier-forming body or sealant is disposed within the housing. In particular, the arc barrier-forming body or sealant is disposed between a portion of the fusible element and each of the conductive elements.
    Type: Grant
    Filed: July 20, 1992
    Date of Patent: September 14, 1993
    Assignee: Littelfuse, Inc.
    Inventor: Cesar Herbias
  • Patent number: 5235307
    Abstract: A solderless cartridge fuse comprises an open-ended insulating housing made of a relatively rigid, unyielding material. End caps close the open ends of the housing. Each end cap comprises an end wall confronting the adjacent housing end and a flexible yieldable side wall which, in its pre-formed state, has a lesser size than the periphery of the adjacent end of the housing so that there is a tight interference fit between the conductive end cap side wall and the housing periphery. A fuse element extends diagonally across the interior of the housing. Prior to application of the end caps to the housing ends during fuse assembly, the fuse wire ends are bent back around the housing ends so to be tightly sandwiched between the side walls of the end caps and the housing when the end caps are applied thereover.
    Type: Grant
    Filed: August 10, 1992
    Date of Patent: August 10, 1993
    Assignee: Littelfuse, Inc.
    Inventor: Seibang Oh
  • Patent number: 5229739
    Abstract: A fuse for handling normal load currents substantially in excess of about 80 amps, the fuse comprising a metal portion formed of an integral piece of metal having outermost, spaced terminal-forming portions with bolt-anchoring holes therein and a fuse link-forming intermediate portion between the terminal-forming portions. The terminal-forming portions of the metal piece has a rectangular configuration having inner margins spaced from one another. The fuse link-forming portion of the metal piece has an S-shape with one face thereof being co-planar with one of the faces of the terminal-forming portions thereof. The thickness of the S-shaped fuse link is only a fraction of the thickness of the terminal thickness and has outermost legs respectively extending from the opposite sides of the innermost margins of the terminal-forming portions of the metal piece and a central link interconnecting the outermost legs.
    Type: Grant
    Filed: February 21, 1992
    Date of Patent: July 20, 1993
    Assignee: Littelfuse, Inc.
    Inventors: Seibang Oh, Robert Madland
  • Patent number: 5214406
    Abstract: A surface-mounted fuse has a hollow, open-ended insulating fuse body with a square sided central portion terminating in opposite, preferably square-sided, recessed, tapered end portions. A pair of preferably square-sided conductive end caps are provided having end walls respectively confronting the open ends of the fuse body and side walls enveloping the tapered end portions thereof. The side walls of the end caps define annular tapered cavities to receive without compressing the fuse wire one or more bent back ends of a fuse wire. The recessing of the tapered end portions of the fuse body provides axially outwardly facing abutment shoulders which limit the extent to which the end caps can be moved over the fuse body during assembly. The end walls of the end caps are then spaced from the ends of the fuse body to form outer spaces of greater size than the fuse element thickness, so that the ends of the fuse element are not compressed between the end cap end walls and the ends of the fuse body.
    Type: Grant
    Filed: February 28, 1992
    Date of Patent: May 25, 1993
    Assignee: Littelfuse, Inc.
    Inventors: Lloyd W. Reese, Larry J. Brashear, Daniel B. Onken
  • Patent number: 5142262
    Abstract: A slow blowing fuse includes an open-ended rigid housing defining a fuse element-containing space therein. Conductive end caps close off the ends of the housing and act as electric terminals for the fuse. A spiral wound fuse element in said space extends between the end caps. The spiral wound fuse element comprises a core of flexible material around which is spirally wound a fuse filament which is electrically connected to the end caps. The spiral wound fuse element is sandwiched between the end caps to provide a configuration where at least the central portion thereof is located adjacent to the housing walls.
    Type: Grant
    Filed: June 24, 1991
    Date of Patent: August 25, 1992
    Assignee: Littelfuse, Inc.
    Inventor: Daniel Onken
  • Patent number: 5139443
    Abstract: A fuse assembly has a one-piece molded housing providing alignment and guiding surfaces for insertion of a generally planar fuse assembly having side elements carrying a fuse link or diode therebetween. In one version the housing has an open bottom through which terminal blades formed as extensions of the side elements extend. A load-bearing structure prevents accidental fuse element assembly withdrawal from the housing. Polarized terminals for polarized devices such as diodes are provided by twisting one of the initially coplanar blades 90.degree.. The twisted joining portion between the so rotated terminal blade and its remaining structure inside the housing is disposed completely within the housing so as to provide a flush-mounting plug-in structure.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: August 18, 1992
    Assignee: Littelfuse, Inc.
    Inventor: John E. Armando
  • Patent number: 5003281
    Abstract: A cylindrical cartridge-type fuse has terminal end caps configured to provide insertion-limiting shoulders arresting the movement of the insulating fuse housing sleeve into the caps during assembly, and further configured with solder-retaining wells having surfaces configured to aligningly guide an inserted fuse element into a generally central location when the sleeve and fuse element are forced into the cap with the solder in a molten condition. Accidental solder voiding arising from the displacement caused by the sleeve and the fuse element is eliminated, and a centered fuse element is provided, secured by an adequate mass of solder therearound. Additional mechanical strength is optionally imparted to the system by coating the finished structure with an adherent plastic or resin material.
    Type: Grant
    Filed: January 16, 1990
    Date of Patent: March 26, 1991
    Assignee: Littelfuse, Inc.
    Inventor: Lloyd W. Reese
  • Patent number: 4997393
    Abstract: A fuse assembly has a one-piece molded housing providing alignment and guiding surfaces for insertion of a generally planar fuse assembly having side elements carrying a fuse link or diode therebetween. In one version the housing has an open bottom through which terminal blades formed as extensions of the side elements extend. A load-bearing structure prevents accidental fuse element assembly withdrawl from the housing. Polarized terminals for polarized devices such as diodes are provided by twisting one of the initially coplanar blades 90.degree.. The twisted joining portion between the so rotated terminal blade and its remaining structure inside the housing is disposed completely within the housing so as to provide a flushmounting plug-in structure.
    Type: Grant
    Filed: March 23, 1989
    Date of Patent: March 5, 1991
    Assignee: Littelfuse, Inc.
    Inventor: John E. Armando
  • Patent number: 4973932
    Abstract: A fuse comprises a housing filled with arc-quenching material, terminals at the opposite ends of said housing, and a fuse element assembly in the housing connected between the terminals. The fuse element assembly has at least one short circuit blowing section and a center-melting slow blowing section, both disposed within an unpartitioned space in the housing, so that the entire body of arc-quenching material affects the short circuit blowing section of the fuse. The slow blowing fuse section has a surrounding layer of thermoplastic material which prevents the oxidation thereof and becomes plastic at the melting temperature of the time delay element. During the fuse element melting attendant to blowout, plastic deformation allows necessary geometric change in fuse element shape and facilitates collapse of the slow blowing fuse section.
    Type: Grant
    Filed: December 8, 1989
    Date of Patent: November 27, 1990
    Assignee: Littelfuse, Inc.
    Inventors: David J. Krueger, Robert G. Swensen
  • Patent number: 4962363
    Abstract: A surface mountable leadless fuse generally includes a tubular fuse sub-assembly with an insulating body molded thereto in intimate sealing relation. The tubular fuse sub-assembly includes a nonconductive tubular housing, cup-shaped metal end caps enclosing the housing. The insulating body includes an upper and lower portion which are integral as molded. The end caps protrude from a bottom surface of the insulating body so that the fuse can engage the flat conductive areas of a circuit board for soldering thereto without obstructiion of the insulting body. The end caps also protrude from the end surfaces so that visual inspection and solder wetting are unobstructed. The lower portion of the insulating body covers an exposed portion of the tubular housing. A pair of anti-rolling legs depend from opposed margins of the bottom surface to prevent the fuse from rolling off of the circuit board once placed there.
    Type: Grant
    Filed: April 10, 1989
    Date of Patent: October 9, 1990
    Assignee: Littelfuse, Inc.
    Inventor: William F. Sexton, Jr.
  • Patent number: 4768968
    Abstract: An improved fuse holder for cartridge electrical fuses features snap-in terminal clips which engage the side barrier walls of a unitary insulating mounting base. The barrier side walls partially shroud the clips from accidental contact by external objects. The metal rivet normally used to secure a fuse clip to a base is eliminated, permitting a lower fuse holder profile for a given voltage requirement. Optional additional subsequent hot-forming of a clip-engaging post on the base provides extra pull strength to the structure. A limited rotation capability of the clips facilitates fuse insertion without breakage.
    Type: Grant
    Filed: May 24, 1984
    Date of Patent: September 6, 1988
    Assignee: Littelfuse, Inc.
    Inventors: Charles W. Daggett, Julius A. Nemeth
  • Patent number: 4767339
    Abstract: A modular fuseblock furnishes dovetail joint grooves and ridges that are accessible from above on both sides of the fuseblock. This provides for interlocking or joining additional fuseblocks on either side of a panel mounted fuseblock without unfastening the mounted fuseblock. Pilot grooves and ridges extending upwardly respectively from the dovetail grooves and ridges aid in engaging the dovetail groove and ridge joint means. Locking tabs on the sides of the fuseblock body detent joined fuseblocks to maintain them fixed in vertical position and end walls that ride in vertical tracks in the two side walls of the fuseblock prevent intrusion to the fuse clips and electrical connections from the ends of the fuseblock. An adapter provides mounting the fuseblock on a channel member while using the dovetail joint grooves and ridges. The adapter mounts on the channel member through rotational movement, and the fuseblock mounts on the adapter through translational movement.
    Type: Grant
    Filed: March 10, 1987
    Date of Patent: August 30, 1988
    Assignee: Littelfuse, Inc.
    Inventor: Joseph D. Comerci
  • Patent number: 4762510
    Abstract: A fuseholder socket assembly including a side terminal with preferably a pair of helical knob contact finger-engaging surfaces for initially guiding a knob for movement in both axial and circumferential directions toward a locking position where a pair of J-shaped knob contact fingers can interlock with a socket body side terminal with not more than about one-half turn of the knob. The assembly includes a pair of axially inwardly facing abutment shoulders preferably formed by a pair of rigid channel-forming fixed fingers projecting from the side terminal and against which knob contact fingers are urged by a biasing means when the knob is turned into a final locking position and then released. Good electrical contact is preferably achieved by a pair of body side terminal outwardly axially projecting, radially outwardly deflectable resilient contact arms.
    Type: Grant
    Filed: April 6, 1987
    Date of Patent: August 9, 1988
    Assignee: Littelfuse, Inc.
    Inventor: Rudolf K. Schaefer