Abstract: A reconfigurable serial loop multiplex communication system for communication of digital and analog status and control information between field terminal locations or to a central control location via a twisted pair line. Input modules in a first terminal station communicate signals received at their input to output modules having the same byte address in other terminal stations. At the central control locaton, signals from an input module may be readdressed for communication to output modules having a different byte address.

Abstract: A toggle switch having a molded insulating frame mounting a snap-in bushing secured thereto for snap-in mounting of the switch in a hole in a mounting pane. This bushing pivotally retains the toggle lever for operating the switch contacts within the base. This frame includes a pair of depending legs between which the insulating switch base is snap-in mounted and retained. This frame has integrally molded therewith a pair of oppositely disposed resilient back-up elements for pressing against the back of the panel, these elements having at their ends ramped riser bars for accommodating a range of different panel thicknesses while retaining the switch against significant movement on the panel during toggle lever operation.

Abstract: An absolute calibration system for a wideband superheterodyne receiver in which a fixed-frequency signal source supplies an IF signal to the mixer for conversion to an RF signal. The RF signal produced in this manner passes through the RF components of the receiver to the input port of the receiver where it is detected by a wideband detector. The video output signal from the detector provides an indication of the RF gain of the receiver required for calibration. The calibration results provided by the IF signal are compared to that provided by a single frequency, absolute calibrated RF source to produce a correction factor which is applied to the IF calibration data over the entire RF band.

Abstract: A calibration system for a wideband superheterodyne receiver in which a fixed-frequency signal source supplies an IF signal to the mixer for conversion to an RF signal. The RF signal produced in this manner passes through the RF components of the receiver to the input port of the receiver where it is detected by a wideband detector. The video output signal from the detector provides an indication of the RF gain of the receiver required for calibration. The fixed frequency IF signal may be converted to an RF signal for calibration purposes at every frequency that the receiver can accommodate merely by sweeping the local oscillator throughout its frequency range.

Abstract: A speed control subassembly is made by providing a generally flat heat sink plate having a laterally-formed collector strip at its upper edge. A double-sided-adhesive insulator tape strip is stuck to the heat sink, this tape having a hole large enough to receive a thyristor chip so that the thyristor anode contacts the heat sink with solder paste therebetween. Two formed terminal strips extending in opposite directions are stuck to the tape so that one contacts the cathode and the other contacts the gate of the thyristor chip with solder paste therebetween. A chip capacitor is placed across the terminal strips with solder paste therebetween. A small force is applied to the capacitor and then heat is applied to the stack of parts to solder the parts together and to the heat sink and to set the adhesive resin. This subassembly is then placed into a trigger switch housing and connected to the contacts and variable resistor thereof to provide a trigger speed control switch for portable tools.

Abstract: A toggle switch having an insulating housing that completely encloses all metal parts enabling connection of "live" wires to the switch terminals safely. The housing includes a molded base and a molded snap-in cover. A toggle lever supporting bushing is clamped between the base and cover and is provided with a snap-in collar for snap-in mounting the switch in a hole in a mounting panel. The toggle lever actuates an over-center wire link that imparts shear and wiping motion and snap-action to butt contacts. The terminals have insulation shearing slots into which unstripped wires are forced to make electrical connections. An integrally molded plug overlies a hole in the cover and is connected to the cover by thin sections which break when the plug is depressed into such hole to force the wires into the connectors.

Abstract: A low inductance resistor comprising a metalized, planar silicon wafer, positioned beneath the emitter tabs of an RF power transistor to provide dc balancing and stabilization and thus eliminate the need for more costly collector feedback circuits.

Abstract: A chopper for adjustably controlling the average value of the voltage supplied from a D.C. battery source to a motor load for adjustable speed control. The chopper comprises manually-operable spring-biasing means for applying force to close a contact to energize the motor and electromagnetic means simultaneously energized for re-opening the contact. This occurs at a high repetition rate so that the average value of the voltage across the motor determines the motor speed. This average value of voltage is proportional to the closed-to-open time ratio of the contact and is adjustable by manual control. Two versions are disclosed. In the first version, the spring-biasing force is applied to the contact by depressing a trigger. In the second version, the spring-biasing force is applied to the contact by rotation of a knob. Both versions may use either tension or compression spring force.

Abstract: A two-piece snap-on yarn trapper including a molded U-shaped bracket that snaps onto a yarn detector switch and supports a plural-turn helical spring. This spring is held inwardly bowed in the bracket so that the turns are held open or separated on the yarn side to provide a series of V-grooves for receiving the yarn that is drawn tightly thereinto by the trip lever of the yarn detector switch thereby to trap the yarn when it goes slack. The bracket is provided with a pair of inner edges or guides to guide the yarn to the middle portion of the helix where trapping is most effective and reliable. The helical spring is compressed and snap-in assembled on a pair of angularly-disposed stubs received in opposite ends thereof to hold the spring in its bowed condition on the bracket due to the tension of the helix.

Abstract: Improved pivoting and sliding contactors and an operating member for lever and rocker operated electric switches are disclosed. A resiliently pivotally mounted forked operating member engages with the contactors adjacent opposite sides thereof and pivots and slides the contactors on a common contact terminal into and out of sliding engagement with contact terminals on either side of the common terminal. Separate contactor forms for maintained ON-OFF-ON and momentary ON-ON type circuit commutations are used.

Abstract: An electric snap-action electric switch is disclosed which employs movable contact means having an inverted V-shaped cam surface. The movable contact means is spring biased into engagement along its cam surface with the end of a pivoted operator lever. Upon movement from one extreme position the lever cams and pivots the contact means inwardly of the switch until the end of the lever rides beyond the apex of the V-shaped surface, whereupon the contact means moves with snap action under spring action to change switch circuits. Contact wiping action occurs during inward pivotal movement of said contact means, and abutting stationary contact engagement results from its snap-action movement.

Abstract: An off-lock for a toggle switch of the type having a slotted guide plate and a spring-biased toggle lever having flats on opposite sides of the portion thereof extending through the elongated slot in the guide plate to confine the toggle lever for non-rotatable pivotal motion. The lever lock consists of arcuate grooves around the toggle lever slightly above the guide plate deep enough to allow rotation of the toggle lever after it is pressed down to bring such grooves to the level of the guide plate. For off-lock in its center off position, the toggle lever is pressed down against the force of the plunger springs and turned 90.degree. so as to cause the opposite edges of the slot in the guide plate to mesh with the arcuate grooves and thus lock the toggle lever against pivotal movement. To release the off-lock, the toggle lever is turned 90.degree. whereupon it snaps up to normal position allowing pivotal movement.

Abstract: An electric snap-action switch is disclosed having a movable contactor with oppositely inclined camming surfaces meeting at an apex on the top thereof. The contactor is centrally biased upwardly from below and cammed downwardly from above by a laterally movable operator traversing the inclined camming surfaces such that the contactor snaps laterally against vertical stationary contacts as the apex is crossed by the operator.

Abstract: A snap-action overcenter contact mechanism utilizes a spring-loaded apexed plunger depressibly cammed within a rockable actuator block. The plunger rides in tracks in the block which ensure registered pivotal movement of the block and plunger, and also guides the plunger for depression within the block perpendicular to the pivotal axis thereof. A cam, which may be in the form of a roller mounted to a linearly sliding operator or a toggle lever operator, traverses the plunger to depress the plunger within the block against the bias of compression springs. When the cam translationally crosses the apex of the plunger, the stored energy of the springs is released, and the plunger and block pivot to an alternate position. A positive off feature is also disclosed wherein secondary cams formed on the operator strike the block to force it to pivot to an off position if the first cam has crossed the apex of the plunger and the block has not pivoted to the off position.

Abstract: A switching system having a photo-sensitive power switching or control element such as a photo SCR, photo triac, photo transistor or the like that is normally turned on or off by coupled light from a controlled light source such as an LED (light emitting diode), neon lamp, incandescent lamp or the like. A thermally-sensitive light-gating element such as an LC (liquid crystal) element controls the light impinging on the photo-sensitive element. The gating element may sense the temperature of the photo-sensitive power switching or control element directly if the two are integral in which case the combined device would be self-protecting. On the other hand, the gating element may be separate and may be arranged to sense the temperature of an external source that may or may not be controlled by the photo-sensitive power switching or control element in which case the latter would be controlled by the temperature.

Abstract: In the exemplary embodiment, an attachment is mounted to the switch housing and supports stationary supply terminals which extend through the switch housing to make sliding and wiping contact externally of the housing with the terminals of an indicator lamp carried by the switch operator when the latter is moved to a designated position.

Abstract: The snap-in mounting means includes a ring-like retainer member disposed in an annular groove provided near the outer end of an elongated bushing which extends from a switch frame member on a switch base of an electrical toggle switch assembly and pivotally supports a toggle lever for actuating switch contacts housed in the switch base. The retainer member is radially compressible and expandable in the bushing groove between a normally expanded position where its outer dimension is larger than the dimension of the mounting hole in a support panel on which a switch assembly is to be mounted and a compressed position where it can pass through the mounting hole.As the bushing is initially inserted into the mounting hole from the rear of the panel during mounting, a portion of the retainer member engages the rim of the mounting hole and it is cammed thereby to the compressed position inside the groove.

Abstract: Thermally sensitive silicon thyristors capable of intrinsically switching between high and low resistance states in response to a predetermined temperature in the range -30.degree. C to +150.degree. C; this intrinsic switching temperature being not only lower than heretofore achieved but also predictably determinable. The two terminal breakover voltage is nominally equal to one-half Vmax at a temperature less than 50.degree. C, where Vmax is the maximum value of the two terminal breakover voltage of the thyristor with respect to temperature.

Abstract: A thermostatic control as shown and claimed in U.S. Pat. No. 3,135,849 in which the reed in this new disclosure has a pair of split legs. One leg of a first set of such pair is a flipper leg and the other leg of such first set carries a contact which is designed to be resistant to erosion from arcing and welding. One leg of another set of such pair of legs carries a contact which is designed to carry current in excess of 20 amp. at 250 V, the other leg of said other set is a flipper leg. A lost motion slot in a flipper spring provides a sequential drive for the two contacts carrying legs such that the arc resisting contact both makes and breaks the electrical circuit and the current carrying contact never makes or breaks the circuit but merely carries the current established by the arc resisting contact.The control as shown also eliminates a force multiplying adjusting lever and a pivot interface between such lever and the range lever.

Abstract: EMI (electromagnetic interference) is prevented by grounding the switch operator. This is done by placing an electrically conductive spring brush within the switch housing to connect the toggle lever to the metal frame of the switch. Since the metal frame is connected through its mounting panel to ground, the toggle lever becomes grounded to prevent EMI.