Abstract: A table that is useful alone and in combination with a tray and/or other inserts supported atop the table. The table is of a unitary molded plastic construction and is configured for nested stacking with like tables for convenient and compact storage and handling. The table has a top surface of regular polygonal shape with four truncated corners, and a plurality of legs depending from the table top at respective ones of the truncated corners. The legs, going from top to bottom, diverge outwardly with each being in the form of a channel that opens inwardly for nested receipt of a corresponding leg of a subjacent table of like construction. The table top has an upstanding marginal rim extending along the peripheral edge of the top surface thereof, and the marginal rim functions to prevent objects from rolling or sliding off the top surface and/or as containment structure for an insert such as a decorative panel and/or a removable tray that may have a design printed thereon.

Abstract: A method and apparatus of quench hardening to a desired depth the full axial extent of the wall surface, or selected portions of the wall surface, of an axially extending bore in an elongated workpiece wherein the bore has a selected uniform cross-sectional shape throughout the length thereof and is closed at one end, which method and apparatus involves providing an inductor with an outer shape generally matching but smaller than the cross-sectional shape of the bore to permit passage of the inductor through the bore, supporting the workpiece with the axis of the bore extending vertically and the open end facing downward, electrically energizing the inductor with a known frequency and at a selected power level, passing the energized inductor upwardly through the bore to inductively heat the wall surface of the bore progressively upwardly from the lower end thereof while progressively liquid quenching the wall surface immediately below the inductor during the upward passage thereof through the bore, and direct

Abstract: Method and apparatus for heating a billet of magnetic metal material to a forging or other elevated processing temperature above the Curie point temperature of the workpiece metal by first inductively preheating the billet in an induction heating coil to a preheat temperature not appreciably higher than the Curie point temperature of the workpiece metal, and then conveying the preheated billet from the induction heating coil into, and post-heating it to the elevated processing temperature within, the heating chamber of a slot-type high efficiency electric radiant heat electric furnace.

Abstract: Method and apparatus for heating a billet of nonmagnetic metal material to forging temperature by first preheating the billet in a high efficiency slot-type electric radiant heat furnace to a preheat temperature a substantial level below the forging temperature, and then conveying the preheated billet from the furnace immediately into an inductive heating coil and energizing the coil to inductively post-heat the billet to the forging temperature.

Abstract: Apparatus for inductively heating a non-rotating workpiece includes a rotatable spindle of insulating material having a split-ring secondary mounted thereon for rotation therewith and which secondary has opposite ends electrically connected in series with the opposite ends of a multiple turn inductor coil. A primary winding in the form of a split-ring is supported in fixed coaxial relationship with respect to the spindle and the secondary ring thereon, and opposite ends of the primary ring are connected across a source of high frequency alternating current. The apparatus is mounted on a slide for displacement toward and away from a workpiece to selectively position the inductor in magnetically coupled relationship with the workpiece, whereby the workpiece is inductively heated in response to rotation of the spindle and energization of the primary ring.

Abstract: A method of hot-shearing an elongated metal bar into sections of given gauge length comprises longitudinally indexing the metal bar to position cross-sectional zones thereof where it is to be sheared successively at a plurality of heating stations at which the shear zones of the bar are progressively heated by resistance heating units to reduce the force required for subsequent shearing of the bar through the heated shear zones on ensuing index thereof to a shearing station.

Abstract: A method and apparatus of quench hardening to a desired depth the full axial extent of the wall surface, or selected portions of the wall surface, of an axially extending bore in an elongated workpiece wherein the bore has a selected uniform cross-sectional shape throughout the length thereof and is closed at one end, which method and apparatus involves providing an inductor with an outer shape generally matching but smaller than the cross-sectional shape of the bore to permit passage of the inductor through the bore, supporting the workpiece with the axis of the bore extending vertically and the open end facing downward, electrically energizing the inductor with a known frequency and at a selected power level, passing the energized inductor upwardly through the bore to inductively heat the wall surface of the bore progressively upwardly from the lower end thereof while progressively liquid quenching the wall surface immediately below the inductor during the upward passage thereof through the bore, and direct

Abstract: A method and apparatus for hardening a small internal passage in a workpiece wherein the workpiece is indexed into coaxial alignment between axially spaced inductor coils and an actuator telescopically inserts a magnetically permeable flux concentrating rod through the passage, and coextensive with the coils and in inductive relationship with the interior surface, such that upon energization of the coils, flux is concentrated in the concentrating rod and effectively inductively delivered to the surface to raise the temperature thereof to a heat treating temperature, the actuator being extended to another position wherein a quenching ring is disposed adjacent to the surface for delivering coolant thereto to quench harden the surface, the actuator being finally retracted to allow sequential indexing of workpieces.

Abstract: A method and apparatus are provided for an improved power inverter circuit, including a separate starting inverter having an A.C. output applied across a load prior to energizing the main inverter, and driven by a series of repeating gating signals. On achieving a preselected load condition, the starting inverter is removed from the circuit and the main power inverter is energized.

Abstract: A method and apparatus for controlling the frequency of a power inverter for converting D.C. current into A.C. current having a frequency controlled by gating signals, which apparatus and method includes a load voltage detector for deriving a voltage wave; a load current detector for deriving a current wave; a phase shifter to shift the phase of one of the waves by 90.degree.; a multiplier to multiply the voltage and current waves; one with the other to produce a product; a reference signal for comparison with the product to create a control signal; and, a gating signal controller responding to the control signal.

Abstract: Method and apparatus for uniformly heating a workpiece such as a sucker rod or the like having a uniform cross-section over a major portion of its length and an enlargement adjacent each end thereof. A multi-turn inductor is coaxially disposed around a portion of an elongated workpath with the rod being longitudinally moved at some preselected rate of travel along the workpath toward the inductor entrance end. The inductor is normally at a first level of energization adapted to inductively heat the rod major portion to some predetermined temperature as it passes through the inductor. Sensing a preselected power absorption level by the rod as the enlargement adjacent the leading end is inductively coupled with the inductor causes the inductor to be automatically placed at a second, higher level of energization for heating the enlargement to the predetermined temperature.

Abstract: A transformer having a laminated core and a coil enclosing a leg portion of the core, has a thin plastic frame means interleaved between an adjacent pair of core laminations in liquid-tight relation therewith to form, with the pair of core laminations, a completely enclosed internal passageway in the core for the circulation therethrough of a liquid cooling medium for cooling the core during transformer operation. The frame means has inlet and outlet connections projecting outwardly of the core for connection to a supply of a liquid cooling medium, and they communicate with the opposite ends of the internal cooling liquid passageway in the core through slot-shaped openings extending edgewise through the frame side walls.

Abstract: A device for inductively heating simultaneously and alike a plurality of identical elongated workpieces each having at least two axially spaced portions, to produce identical predetermined heat profiles in the workpiece throughout their longitudinal extents. The workpieces are conveyed at a predetermined uniform speed along work paths extending in a linear direction. A plurality of like multi-turn induction heating coils are coaxially disposed along the work paths and connected to a two-level power source. A reciprocal stop aligns the leading ends of the workpieces along the feed paths relative to the heating coils. The coils are at a first level of energization adapted to inductively heat the first axial portion of the respective workpieces identically to the same predetermined temperature as they pass through the coils.

Abstract: A sucker rod fitting for connecting together in an end-to-end relationship a plurality of sucker rods to form a sucker rod string for driving a pump in an oil well by an above ground oil pumping unit, the fitting comprising an elongated body having a central bore extending from an open end to a closed end, and the bore being defined at its end sections by cylindrical end walls, and between its end sections by alternately converging and diverging tapered sections which cause any breakage in a retained sucker rod to occur within the fitting.

Abstract: A method and apparatus of quench hardening to a desired depth the inner surface of an axially extending bore in an elongated, thin-walled workpiece having an outer, axially extending surface wherein the bore has a selected, uniform cross-sectional shape, which method and apparatus involves providing an inductor with an outer shape generally matching, but smaller than, the cross-sectional shape of the bore, supporting the workpiece with the axis entending vertically, energizing the inductor with a known frequency and at a selected power level, moving the energized inductor downwardly through the bore to inductively heat the inner surface progressively while applying no fluid quench to the inner surface, letting the workpiece cool and then moving the inductor upwardly through the bore to progressively heat the inner surface while progressively liquid quenching the inner surface immediately below and after the progressive heating operation.

Abstract: An induction heating arrangement for heating an end length of a forging bar following the cut-off therefrom of a previously heated and forged end length is arranged to heat the end length to a uniform temperature despite the existence of a residually heated terminal end from the previous heat. The heating arrangement has an induction heating coil with a longitudinally extending axial passageway therethrough for receiving the bar length to be heated by insertion into the passageway through the feed-in end thereof. A reciprocable flux diverter or robber ring is moved into the open other end of the coil passageway to surround the residually heated terminal end of the inserted bar end length, during a predetermined portion of the total coil heating cycle, to divert the flux from and prevent it from penetrating and heating the residually heated terminal end, whereby the inserted bar end length is evenly heated throughout its entire axial extent to the desired uniform forging temperature.

Abstract: A method and inductor are provided for annealing the corners of an elongate hollow structural beam in which the corners become work hardened when the beam is produced by cold working initially flat metal plate to the hollow beam configuration. The corners of the beam are inductively heated progressively along the length of the beam in a manner which concentrates heat in the corners and controls the spreading of heat into the sides of the beam from the corners so that the work hardened areas are annealed to provide for the corners and walls to be more uniform in hardness and strength in connection with use of the beam as a structural member.

Abstract: A method and apparatus for heating a conical valve seat surface of a valve seat ring insert which has been previously press fitted or molded into an engine component such as an engine head. The method and apparatus includes mounting an inductor for reciprocal movement axially toward and away from the valve seat of the engine head and biasing the inductor toward the valve seat, encircling the inductor with an axially biased electrically conducting hollow ring-shaped magnetic flux shield through which a coolant is circulated, and moving the inductor and conducting ring shield toward the valve seat of the engine head to locate the inductor in a preselected position providing the necessary magnetic coupling gap between the inductor and valve seat surface of the valve seat insert while the conducting ring shield is maintained in heat transfer surface contact with and stray flux shielding relation to the portion of the engine head immediately around the valve seat surface of the insert.

Abstract: A method for uniformly heating a workpiece such as a sucker rod or the like having a uniform cross-section over a major portion of its length and an enlargement adjacent each end thereof. A multi-turn inductor is coaxially disposed around an elongated workpath with the rod being longitudinally moved along the workpath at some preselected rate of travel toward the inductor entrance end. The inductor is normally at one level of energization adapted to inductively heat the enlargement adjacent the rod leading end to some predetermined temperature as it passes through the inductor. After a first predetermined time interval triggered by the rod as it travels along the workpath, the inductor is automatically placed at another, lower level of energization for inductively heating the elongated major portion to the same predetermined temperature.