Abstract: A low profile semiconductor clamp with force indicating means is disclosed. A resiliently compressive spring washer, such as a belleville, is incentrically disposed within and bowed above an annularly larger indicator washer. The washers rest on a base member to which a clamping force is to be applied by tightening a nut down on a threaded stud extending freely up through the base member and the washers. A load washer is disposed between the nut and the spring washer. In unclamped condition, the load washer rests on the spring washer and hence is spaced above the indicator washer, whereby the indicator washer may be freely manually rotated about the stud. Upon tightening the nut, the load washer compresses the spring washer until the load washer engages the indicator washer to impede manual rotation thereof due to its frictional binding between the load washer and the base member.

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: 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 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 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: 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: 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: 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: 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.

Abstract: RFI (radio frequency interference) is eliminated by the placing of a conductive elastomer coating over the toggle lever seal so as to electrically connect the toggle lever to the switch metal frame or housing that is grounded through the mounting panel.

Abstract: A toggle switch having a molded insulating frame including a pair of depending legs between which the insulating switch base is snap-in mounted and retained. The frame includes a bushing having a resilient collar for snap-in mounting of the switch in a hole in a mounting panel. This bushing pivotally retains the toggle lever for operating the switch contacts within the base. The legs of the frame are inwardly curved and tapered so that bases of varying tolerances may be retained thereby rigidly and securely.

Abstract: A line of 2-wire pilot devices using current level as a signal for implementing solid state control systems. A variety of alternative pilot devices such as flag type limit switch, magnetic type proximity switch, capacitance type proximity switch and temperature responsive switch, in addition to pushbutton switch, are usable as logic inputs to the system based upon two intermediate current levels. Shorted lines and open lines are detected by zero voltage and zero current levels, respectively. A variety of alternative outputs such as logic output and relay output are also useable in the system. In addition, tachometer and motion transducer systems with pulse inputs and pulse integrator and non-volatile memory outputs, respectively, are further possible modifications of the system.

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: An improved method and means for making electrical connections for an internal indicating lamp within a small switch. The conducting leads of the lamp and/or a voltage dropping resistor are connected to and held in good electrical engagement with stationary terminals of the switch as an incident to the terminals being seated in place of the switch housing and secured thereto thereby eliminating the need for special connectors or soldering or welding of the leads to the terminals.