Abstract: A multipurpose electric trigger switch adapted to be mounted in the handle of a portable electric tool for controlling the A. C. power circuit and, to afford a higher rating, the switch is provided with double-pole butt contacts. A movable contactor is pivoted and translated on a resilient terminal into wiping and abutting contact with a stationary terminal in response to linear sliding movement of an operator having a cam which engages inclined camming surfaces on the contactor.

Abstract: A toggle lever switch having a central longitudinal bore in the outer handle for housing an LED (light emitting diode) with terminals extending down through the handle and bent laterally outward along the pivotal axis through lateral holes in the spherical portion of the toggle lever to engage inwardly biased stationary terminals extending up through the bushing adjacently facing the lateral holes. The LED terminals themslves are used as the commutating connectors. Commutation means are provided for spacing the LED terminals and for maintaining good electrical contact with the stationary terminals, and in preferred form comprises an insulating plug having a pigtail.

Abstract: A tool for removing a snap-in bushing type toggle switch or the like from a hole in a mounting panel. The tool is molded of plastic material and is provided with a spring-biased self-opening slidable chuck snap-in assembled within a compressor tube and is adapted to squeeze the snap-in collar or skirt of the snap-in bushing so that it becomes released from the mounting panel. The outer compressor tube having a mushroom handle at one end is adapted to slide forwardly over the chuck to compress or squeeze it and the snap-in collar therewithin. A spring-biased ejector pin slidable within the chuck is depressed by the toggle lever of the switch and is loaded by its spring compressed by the compressor tube and serves to snap the switch from the panel hole upon release of the snap-in collar.A first version has an integrally-molded resilient lug on the chuck that snaps out into an elongated slot in the compressor tube wall to snap-in assemble the chuck within the compressor tube for limited sliding movement.

Abstract: A snap-action pressure switch has an adjustable trip point for controlling the switching pressure. A flexible bracket has a bearing portion pivotally mounting a lever between the ends thereof. Contact means are actuated by one end of the lever. A toggle spring is biased between the other end of the lever and a pressure-responsive actuator for causing snap-action pivoting of the lever when the toggle spring passes through an overcenter force-reversing toggle point as the actuator moves in response to pressure. The bearing portion of the flexible bracket is adjustably movable with respect to the actuator, thus moving the pivot point of the lever to change the toggle point of the spring with respect to movement of the actuator, whereby to afford an adjustable switching pressure. The trip point is further controlled by an adjustble range spring biasing the actuator against pressure-induced movement.

Abstract: A tool for removing a snap-in bushing type toggle switch from a hole in a mounting panel. The tool is made of metal or plastic and is provided with a spring-biased self-opening chuck and compressor tube adapted to squeeze the snap-in collar or skirt of the snap-in bushing so that it can be pushed back through the hole in the panel for removal. An outer, compressor tube having a mushroom handle at one end is adapted to slide forwardly over the chuck to compress or squeeze it and the snap-in collar therewithin. A spring-biased ejector pin within the chuck is depressed by the toggle lever and serves to snap the switch out upon release of the snap-in collar. The tool is used by placing the chuck over the snap-in bushing against the panel and pressing on the mushroom handle to slide the compressor tube over the chuck against the panel whereupon the ejector pin kicks the switch out behind the panel.A simpler version includes only a chuck and a manually slidable compressor ring, both molded of plastic material.

Abstract: An annular resistor, suitable for use in a diesel electric locomotive dynamic braking system and the like, having a supporting frame including spaced inner and outer annular frame portions and a continuous resistance ribbon having a plurality of bent-back radial extensions therebetween and in electrical isolation therefrom. U-shaped folds of the ribbon are mounted on pin supports allowing contraction and expansion of the ribbon. The pin supports are mounted to insulator blocks which may be selectively positioned on the frame, when two or more are stacked, to vary ribbon alignment and hence convective cooling. The resistor is comprised of severally replaceable identical component quadrants.

Abstract: An improved thermostatic switch which employs a pressure linear thermal power element and a simplified diaphragm motion translating and amplifying means while dispensing with need for diaphragm loading spring. It features a one piece motion transmitting lever between the diaphragm and electric switch operator, and an improved snap-action switch operating mechanism. A one-piece molded insulating housing, and an improved knob coupling member on the temperature range adjusting shaft are employed.

Abstract: A monolithic semiconductor device is disclosed comprising a power switching thyristor and a temperature sensitive thyristor integrated on a common substrate. In preferred form, the temperature sensitive thyristor is electrically connected between the gate terminal and one of the main terminals of the power switching thyristor, and is thermally actuatable to intrinsically switch from a high to a low resistance state above a predetermined temperature of the power switching thyristor sensed through the common substrate, whereby to shunt gate current and automatically inhibit turn-on of the power switching thyristor to prevent overheating thereof. Depending on circuit variations, the power switching thyristor may be rendered conductive above or below a predetermined temperature, or within a defined temperature range. Normally off and normally on devices are disclosed.

Abstract: A ladder static logic control system having static logic circuits that are logic equivalents of the electromagnetic, mechanical and other circuit components in a prior electromechanical ladder diagram. Ladder static logic circuits that are logic equivalents of electromagnetic devices such as control coils, latching coils and timer coils and having a built-in operating time delay to eliminate any logic race problems. A method of making the above ladder static logic control system by starting with a ladder diagram of a prior art electro-mechanical control system and substituting a ladder static logic circuit for each of the electro-mechanical component counterparts appearing therein.

Abstract: A pneumatic timer translating the external force of an electromagnetic relay or the like into rotational movement of a camshaft to actuate a set of switch contacts. The rotation of the camshaft is retarded in one direction by an adjustable pneumatic one-way time delay mechanism. The timer is capable of two modes of operation, on delay and off delay, according to choice of camshaft configuration and orientation.

Abstract: A system for protecting an electrical resistor, such as, for example, the dynamic braking resistor of a D.C. traction motor used in a diesel-electric locomotive, from burn-out in the event of a malfunction such as a cooling fan failure or air blockage, over-load, high ambient temperature, etc. Such protection is afforded by a noise-immune system that continuously monitors the resistor temperature and provides an output signal when the resistor temperature reaches a predetermined level above its normal operating temperatures short of an unsafe level. This is done by sensing the change in resistivity of the resistor with change in temperature thereof to provide a first control signal. A second control signal proportional to the current in the resistor is obtained and compared with the first control signal to obtain the aforesaid output signal proportional to the resistor temperature above ambient temperature.

Abstract: An electrical contact unit, for example an add-on block for detachable attachment to an electromagnetic relay itself incorporating contact sets driven by the electromagnet, comprising at least one contact set normally biased closed and means for retaining the contact set in the closed condition against an applied actuating force until the actuating force exceeds a threshold value, whereupon the contact set snaps open. The retaining means may comprise a ball bearing urged outwardly from a channel formed in a linearly-movable actuating member for the contact set and a shoulder behind which the ball bearing engages when the contact set is in the closed condition.

Abstract: A laminated core for an A.C. electromagnet comprising its own die for the casting of shading coils therein. Retention grooves formed across the laminations and retention slots formed in side plates provide a continuous path for the injection of molten metal therein, thereby producing a closed-loop shading coil when solidified. Also disclosed is a method for making a core having a shading coil cast in situ.

Abstract: Trigger operated snap-action switches having selectable and adjustable cam inserts in the trigger arranged for engaging the plunger of a snap-action mechanism to afford selection and adjustment of the pre-travel, and in the case of a double pole switch, to afford simultaneous or sequential closing of the contacts as desired.

Abstract: A trapper for trapping the yarn in a knitting machine and holding it, under normal slackening when knitting certain patterns, to prevent unwanted tripping of the detector switch and machine shutdown. This yarn trapper consists of a one-piece wire member having a two-turn helix with a pair of supporting arms bent out radially and outwardly from opposite ends thereof at a common angular point on the periphery of the helix and having inwardly bent mounting hooks at their ends. These arms are held slightly spread apart from their normal relaxed condition when the trapper is snap-mounted on the yarn detector switch to relieve the pressure between each of the half-turns and the full turn and thus provide a pair of semi-circular traps formed by the half turns in light touching contact with different portions of the full turn to frictionally hold even the thinnest yarn if it should be pulled thereinto upon attempted swinging of the trip lever.

Abstract: An electrical terminal having a looped configuration for properly orienting a segment of the terminal to which a contact may be mounted to thereby properly direct a magnetic blow-out force induced by current flow through said segment. The terminal is formed by two longitudinal, parallel 90.degree. bends rather than two lateral, parallel 90.degree. bends, and comprises a flat rectangular member having a U-shaped aperture formed longitudinally therein defining a tongue segment (to which a contact may be mounted) spaced between a pair of longitudinal side segments joined at their ends by a pair of lateral segments bent 90.degree. from the plane of said tongue segment about longitudinal axes co-linear with the legs of the U-shaped aperture.

Abstract: A rocking contactor switch of the two-circuit progressive action type having three spaced stationary contacts, a flexible contactor connected to the first stationary contact and self-biased to disengage the second stationary contact, and a three-position rocking contactor. The switch is operable from an "off" position wherein the rocking contactor engages only the first stationary contact and the flexible contactor to a one circuit "on" position wherein the rocking contactor rocks over to press the flexible contactor into engagement with the second stationary contact while remaining in engagement with the first stationary contact, and then to a two circuit "on" position wherein the rocking contactor rocks further to engage the third stationary contacts while maintaining the flexible contactor pressed against the second stationary contact thereby to connect electrically all three stationary contacts.

Abstract: A rocker switch having a spring-biased lock lever within the contact actuator that extends out to catch beneath the rim of the hole in the frame to lock the rocker button in the "off" position. An insertable key, which may include the entire face of the rocker button, has a projecting cam effective when inserted to retract the lock lever to allow normal operation. Removal of the key prevents unlocking of the rocker switch for operation to "on" position. The lock lever has an angular end that allows actuation of the rocker button from "on" to "off" position even when the key is removed. This angular end cams on the frame to momentarily depress the lock lever and allow it to snap below the rim of the hole in the frame. This lock lever is then inaccessible except to the projecting cam of the key.

Abstract: A unitary three-phase current transformer having its three iron cores and three secondary coils enclosed and retained in their positions by a pair of like molded housing halves. The housing halves also have pairs of juxtaposed slots in their upper, adjacent edges for clamping pairs of secondary coil terminal inserts therebetween to mount the same so as to allow connection of the secondary coils to external conductors. The housing halves are connected together by symmetrically arranged sets of screws with the screws of each set extending through holes in the respective half and threaded into the respectively opposite half. The asembled housing halves provide three apertures through which are inserted respective bus bars serving as one-turn primary windings. A terminal strap is attached to one end of each bus bar, the bus bar is inserted through the aperture, and the other terminal strap is attached to the other end thereof.

Abstract: A branch electrical connection is made at any selected joint of a busway run without disturbing the joint connection in any manner apart from removing a side housing cover plate. A unitary connector assembly is plugged into the exposed side of the joint and bolted to the bus duct housing using the existing bolt holes provided for the joint cover.