Illinois Tool Works Inc.

William G Rodseth

Francis C Peterson

Daniel Gilman

William A Spring

James W Robinson

Ernest J Wendling

A photoelectric switch is sealed against the infiltration of contaminants, for example, oil mist within a combustion-powered tool comprising a switch. In a housing structure sealed by an O-ring when assembled, two photoelectric devices define a line of sight therebetween. A plunger is biased to an inoperative position, in which a shutter portion thereof blocks the line of sight. In an operative position, the shutter portion unblocks the line of sight. The plunger has a stem portion sealed by another O-ring. Where electrical leads from the devices extend through apertures defined within the back member, the apertures are sealed by solder used to connect leads to copper layers, which may be screen-printed upon an outer surface of the back member. A cap mounted upon the back member covers the contacts and admits electrical wires soldered to the layers.

Photoelectric switch sealed against infiltration of contaminants

For a combustion-powered tool, an ignition system is powered by a battery and is arranged so that a sudden discharge of a capacitor, as charged via an oscillator, produces a spark at a spark gap of a spark plug, so that the oscillator is enabled if a trigger switch is closed while a head switch is closed, but not if the trigger switch is closed while the head switch is opened, and if a battery voltage, as monitored, is not less than a reference voltage, and so that a silicon-controlled rectifier, which is arranged to produce a sudden discharge of the capacitor, is switched to a conductive state if the capacitor voltage, as monitored, and is not less than a reference voltage. The head and trigger switches, which are photoelectric, are polled intermittently to determine whether they are closed. Predominantly, solid-state components are used.

Ignition system for combustion-powered tool

The invention relates to a fastener assembly for use in attaching articles to printed circuit boards, and include a fastener, which has a generally tubular body, flanged at one end, is adapted to receive a screw. The fastener has a polygonal cross-section over a portion of its length. The flange which is located at one end of the tubular body, has an integral spring washer and includes indentations which allow solder to flow from one side of the printed circuit board to the other. The fastener with its integral spring washer provides improved clamping characteristics and avoids problems associated with large coefficients of thermal expansion of printed circuit board material in a direction perpendicular to the board.

Printed circuit board fastener

An electrically insulating fastener having three pre-assembled elements. A nut with a tubular body and an integral spring flange has a disc-shaped spacer attached to the flange. The spacer has a central opening with a cylindrical collar formed around it. A flexible and resilient rubber sleeve is fitted over the collar. The nut, spacer, and sleeve form a unitary fastener which can be used with a headed threaded fastener to make electrical connections through heat sinks of various thicknesses.

Electrically insulating fastener for heat sinks of different thicknesses

An insulator used in connecting heat generating electrical components to heat sinks. Fasteners which include insulators of the present invention include flexible engaging means for preassembling an insulating washer portion to a conductive fastener element. The insulators may be made of high performance plastic material or of a coated metal. The fasteners used with the insulators preferably have integral spring washers to maintain thermal conductivity between the components and the associated heat sinks. The insulator preferably have integral bosses which prevent arcing between the conductive fasteners and the heat sinks.

Electrically insulated heat sink assemblies and insulators used therein

The invention includes a method and a fastener for use in attaching articles to printed circuit boards. The fastener, which has a generally tubular body, flanged at one end, is adapted to receive a screw. The fastener has a polygonal cross-section over a portion of its length. The flange which is located at one end of the tubular body, has an integral spring washer and includes indentations which allow solder to flow from one side of the printed circuit board to the other. The fastener with its integral spring washer provides improved clamping characteristics and avoids problems associated with large coefficients of thermal expansion of printed circuit board material in a direction perpendicular to the board.

An electrical connector embodying the present invention includes a planar base member having an aperture and a blade receiving portion comprised of a plurality of resilient legs. The legs have concavo-convex surfaces near their free ends which facilitate insertion of a blade connector. Opposing concavo-convex surfaces are biased toward each other. As a result, the connector has a self-cleaning wiping action, and yet allows a blade connector to be installed with low insertion forces.

Terminal block connector

A self-aligning mounting arrangement for aligning a fastener to secure a first workpiece to a second workpiece. The arrangement includes a plurality of bores each of substantially identical cross-sectional area in one of the workpieces. These bores are arranged in a matrix grid pattern having a predetermined grid dimension. The cross-sectional area of each bore is a predetermined fractional part of the average cross-sectional area of the fastener used to secure the two workpieces. The predetermined grid dimension is a predetermined proportion of a cross-sectional dimension of the fastener.

Self-aligning mounting arrangement

A coupling arrangement includes a fastener driver head and a mating tool drive socket. The fastener driver head comprises a substantially circular disc-shaped base portion, a plurality of frustoconical portions integrally formed with the base portion and concentrically located within one surface thereof. A plurality of ribs are integrally formed with the base portion and alternating with the frustoconical portions and extend axially outwardly of both the base portion and the frustoconical portions. Each of the ribs extends from a line parallel with and spaced above a given diameter of the base portion to an outer periphery of said base portion. A mating drive tool has a recessed driving head or socket substantially complementary with the fastener head for closely interfitting engagement therewith.

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Elgin, IL, United States of America

William G Rodseth