Abstract: A solid state protection system for AC electric motors driving high inertia loads requiring long acceleration times. An electroresponsive relay (OL) is separately responsive to permissible acceleration time, circuitry (DT, DC), acceleration overload current circuitry (ACA), and to normal running overload current circuitry (ACR). Up-to-speed detector and latch circuits (USD, USL) deactivate the acceleration time circuitry and overload current circuitry, and activate the running overload current circuitry upon attainment of normal running speed by the motor. The response levels of the overload and time response circuits are individually settable.

Abstract: A portable electric tool speed control switch of the trigger actuated type having an adjustable trigger stop that affords selective setting of the maximum speed point to any one of a multiplicity of speed points. The trigger stop is integrally mounted in the trigger and abuts the switch housing to limit trigger depression. A spring-biased plunger pin (16) extends rearwardly through the trigger head (10) toward the housing and an adjusting knob (20) recessed in and rotatably mounted in the trigger head has a notched helical track (20b) that engages a tooth at the head of the pin so that rotation of the knob adjusts the plunger pin to provide a trigger stop by abutting the housing at the selected point of trigger depression thus setting the speed point of the tool and affording returning repeatedly to the same speed point.

Abstract: In a joystick controller for electric switches, a resilient bias is provided, biasing the joystick to its neutral position, by means of a garter spring which encircles and embraces two ring members, one ring member being displaced in its own plane in response to pivoting the joystick about its pivot and the other ring member being secured to a fixed housing part. The two ring members are profiled so that the garter spring rides from them upon pivoting the joystick through greater than a threshold angle from its neutral position, so that the bias is removed and the joystick stays put.

Abstract: An improved circuit for energizing and quickly deenergizing the DC operating winding of an electromagnetic relay or contactor from sources of AC supply. It employs a full wave rectifier bridge, a transistor for initiating and maintaining the energization of the relay or contactor control winding when AC is supplied to the bridge, and a zener diode connected in parallel with the main conducting path of the transistor to facilitate quick deenergization of the control winding when the AC supply to the bridge is interrupted.

Abstract: A drive mechanism for converting reciprocating motion into intermittent rotary motion for use in a decimal counter or the like having an integrally molded drive member having two flexibly mounted pawls which are spring biased to insure engagement with the ratchet teeth and two fixed mounted, escapement type, driving and stopping pawls and an integrally molded, driven ratchet wheel, having two concentric rings of teeth, which in turn is coupled to the number wheels. On the impulse movement, the lower, escapement type pawl disengages a ratchet tooth whereafter, nearly simultaneously, first the rear, flexible pawl drives (pulls) the outer, larger diameter ring of teeth at the rear circumferential side thereof a portion of the first clockwise increment of rotation and then the upper, escapement type pawl smoothly engages and drives the smaller diameter ring of teeth for completion of the first clockwise increment of rotation.

Abstract: A gate turn-off device is formed by the integration of a lateral SCR and a vertical power transistor operating in parallel, with the latter carrying most of the load current whereby the former may be easily turned off which in turn terminates base drive to the transistor and thus the device is turned OFF.

Abstract: A one-piece seal for an electric switch for sealing the spaces between a pivotal switch actuator and its supporting frame and between such frame and the switch base. This seal comprises a generally rectangular molded member of resilient material having a bushing extending up into sealing engagement with the pivotal area of the actuator, a land on its upper surface locating and retaining the seal with respect to the aperture in the switch frame, a pair of lugs or pads on its bottom surface for locating and retaining the seal with respect to the switch base, a radius on each of the outwardly facing bights between these lugs and the planar bottom surface of the seal into which the sharp corners of the base bite to effect a tight seal, and thinner sections formed by recesses on opposite sides of the aforesaid land for receiving complementary shelf portions of the frame in combination with thicker side strips or ribs that are pinched between the frame and base for a tight seal.

Abstract: A temperature sensitive thyristor is incorporated with an astable multivibrator to provide active temperature sensing. Below the switching temperature Tsw of the thyristor, an oscillatory signal is present at the output of the multivibrator. When the temperature exceeds Tsw, oscillation ceases because of the shunt path provided through the thyristor when it intrinsically switches to its low resistance on state above Tsw. Cooling results in resumption of oscillation. This is a "fail-safe" arrangement because component failure also provides a warning condition (absence of oscillation).

Abstract: An oscillating stack receiving table carries thereon a pair of cooperating chain driven ejector assemblies which function in their "at rest" position as gates to stabilize the stack of articles during rotation of the table and which are operable to sweep across the table when the latter is "at rest" to eject the stack of articles from the table onto associated take-away conveyor apparatus.

Abstract: A multi-position selector switch of the sliding bridging contact type having a molded plastic base and a metal cover closing the open top of the base and also serving to pivot the operating lever. A plurality of similar one-piece stationary contact-terminals are inserted through holes in the bottom of the base and are held in place by a plastic liner that is dropped in to hug the walls of the base and is clamped down by the cover. The stationary contact-terminals have pairs of wings recessed in the bottom of the base whereby they are held in place by the plastic liner. A movable bridging contact is spring-biased on a reciprocal actuator block that is detented to the cover. The inner end of the operating lever extends into a slot in the actuator block whereby the latter is moved over the stationary contacts from one detent to another. The switch parts are designed for simplicity and east of manufacture and automated assembly.

Abstract: An extremely small time-setting switch adapted for mounting in a hole in the case of an electronic watch and having a coin slot whereby it may be rotated to any one of a plurality of operating positions including a "run" position, a "stop" position, a "minutes change" position, and an "hours change" position. The switch is provided with a generally annular detent structure affording clearance at its middle for the movable contact and affording a better feel including an audible click when rotated into each of its several operating positions and the stationary parts of the switch are locked to one another to prevent movement when the rotary knob is turned in a structure affording an extremely thin, flat package adapted to be staked into the watch case.

Abstract: A trigger switch for a portable electric tool providing substantial pretravel of the trigger before closing force is applied to the contacts. This is a safety measure to prevent the motor from starting if the trigger should be accidentally pressed in handling a circular saw or the like. The pretravel is provided by a telescopic joint between the trigger and contact carrier, each of which is biased independently by a return spring to insure immediate reopening of the contacts upon release of the trigger.

Abstract: RFI (radio frequency interference) is eliminated by placing conductive grease between the toggle lever and its pivot pin in an electric switch to insure good connection of the toggle lever to ground through the housing. This conductive grease also prevents any tendency for the rubber seal material forcing its way into the space between the pivot pin and the toggle lever during the in situ molding operation which otherwise might insulate the toggle lever and cause RFI radiation due to its antenna effect.

Abstract: A round plastic bushing and frame for an electric switch wherein the bushing has a flared collar that is radially squeezed when it is pressed through a round hole from the back of a mounting panel and spreads out in front so that its edge locks the bushing to the panel for great strength retention. A pair of integral spring fingers press against the back of the panel to keep the collar tight against the front of the panel. The integral frame has a pair of parallel arms that hug the switch base and are terminated in hooks that engage notches on opposite sides thereof to secure the integral bushing and frame to the base.In a first version where the bushing and frame cannot be molded integrally into final form, the collar is molded as a radial flange on the projecting end of the bushing and, after removal from the mold, is formed into a frusto-conical collar around the tip of the bushing for snap-in mounting.

Abstract: A method of making electrical contacts of the type having a pair of disk-shaped contacts of precious metal secured to an electrically conductive base member. In this method, continuous flat silver strip is first preformed in a punch press to provide a series of disks left connected to one another at their opposite peripheral edges to afford sufficient stiffness for handling. A pair of these strips are then fed, while maintaining registration therebetween, concurrently with a continuous base member into a brazing or welding machine and are secured to one surface of the base member adjacent opposite edges thereof to form a continuous subassembly strip. This subassembly strip is then fed into a cut-off device with accurate registration so as to make cuts through the connection exactly between adjacent disks of directly opposite pairs thereof and through the base member to provide two round contacts spaced apart on a rectangular base member.

Abstract: A portable tool double-pole trigger switch enclosing a speed control circuit that includes a plastic pack SCR (semi-conductor controlled rectifier) of the sensitive gate type, a capacitor and a variable resistor. In a first version, the mounting tab of the SCR is soldered to a connector that is contacted by the resistor slider. A ceramic capacitor may be used by soldering its leads between the cathode and gate terminals of the SCR, the mounting tab serving as the anode terminal. A chip capacitor may be used by soldering it to bridge the cathode and gate terminals. In another version, the mounting tab may be arranged to be contacted directly by the resistor slider, thus eliminating the aforesaid connector.