Abstract: A chopping type electrical converter having a primary circuit utilizing controlled rectifiers for chopping the input voltage, a secondary circuit for providing a DC output voltage, and a control unit which continuously monitors current flow in the secondary circuit and delays trigger pulses to the controlled rectifiers in the primary circuit whenever it is unsafe or undesirable to trigger them. In a preferred embodiment, the controlled rectifiers are mounted in series-connected pairs with a step-down transformer for each controlled rectifier. The number of pairs and the interwoven triggering order of the controlled rectifiers enables high voltage and high frequency operation with minimal stress on the converter components. The control unit prevents each member of each pair of controlled rectifiers from being triggered whenever the other member of the pair is still conducting, or whenever current is flowing in the secondary winding of the transformer associated with the controlled rectifier.

Abstract: An improved nailing machine having a longitudinally reciprocating nail driving ram and a loose nail feeder means associated therewith, which feeds nails to an alignment chamber positioned in a plane adjacent to the stroke path of the driving ram. The nails are fed into the alignment chamber at an angle to the stroke path of the driving ram whereupon a magnet located adjacent to the driving ram rotates the nail from the initially inclined delivery position and draws it from the alignment chamber into a driving position aligned within the stroke path of the driving ram. The nailing machine may be operated pneumatically to facilitate rapid nailing operations, in which case nails are delivered to the alignment chamber by means of timed bursts of air down a pneumatic transfer tube leading from the loose nail feeder to the alignment chamber.

Abstract: A machine for measuring and cutting predetermined lengths of electric cable such as armored (BX) or insulated cable which is supplied from a coil or reel to a "caterpillar" feed assembly and then to a cutting assembly, the feeding and cutting being synchronized and controlled to effect the cutting, automatically, of a predetermined number of pieces cut to predetermined uniform lengths, the controls including means for measuring the fed cable and for counting the number of pieces.

Abstract: A hand maneuverable sailing rig includes a sail construction having a mast, a sail attached thereto and a bowed, wishbone boom encircling the mast and sail. The wishbone boom is attached to the mast and sail by stays and tie lines. The mast is pivotably supported on mast support means and the resulting sail construction is a highly maneuverable, wind-propelled device suitable for use with roller or ice skates, skateboards or sailboards.

Abstract: A motor control system for AC motors utilizing an inverter which is switched to provide pulsewidth modulated DC voltage to be applied to the motor in phase sequence. The pulsewidth modulation is a function of an input reference signal, a signal dependent on motor current and a boost signal operative at low speeds. The motor voltage is continuously regulated as a function of load to provide the necessary power to drive the load.

Abstract: A metal forming machine for forming articles from metal workpieces has a plurality of driven members for performing work on the metal workpieces. A drive shaft is connected with the driven members for transferring force to the driven members. A frangible portion is connected in the drive shaft and is designed to fail upon the occurrence of a predetermined overload at the member being driven from the drive shaft. A signalling device is associated with the frangible portion to stop the machine and give an alarm when an overload occurs which breaks the frangible portion.

Abstract: A process and apparatus for producing a dust-free blend of additives for use in plastic manufacture wherein the materials are extruded through apertures in a thin die plate supported by a strong die plate support, the apertures in the die plate being larger at their inlet ends than at their outlet ends, and apertures in the die plate support being larger than the die plate apertures, and the product being strand-like pellets of the additive materials.

Abstract: A wrist and ring finger support for bowlers comprising a flexible glove element in combination with a rigid support piece, the glove element having straps for attachment to a bowler's hand and wrist and pocket for receiving a straight flat portion of the support piece in a position to support the wrist, the support piece having an extension at its distal end angled and shaped to provide effective support to the ring finger, as far as, and beyond the first joint. Each element is suitably padded, for the user's comfort.

Abstract: A portable high-rise escape device for attachment to the windowsill of a tall building is disclosed comprising a telescoping length extendible boom, an actuable pneumatic driver for extending the boom, a detachable wall mounting bracket to securely connect the boom to a windowsill, a length of cable having a harness at one end, a winch to contain and release the cable at a predetermined rate, and cable guides to guide the cable from the winch to the end of the boom.

Abstract: A hand tool comprising elements for clamping a conduit or cable to be cut, a saw blade supporting assembly pivotally connected to the clamping elements, in a manner to guide the saw in its desired cutting path, and means for causing sawing movement of the saw blade, the saw blade supporting assembly and the clamping elements being so juxtaposed that they can be gripped by one hand of the tool operator to cause both gripping of the work and advancement of the saw blade in its cutting position; the other hand of the operator being available to effect cutting movement of the saw blade.

Abstract: A strip of interconnected edge clips for attachment to contact pads on a circuit-bearing board, in which a plurality of edge clips each have a free end and a stem end with the stem ends of the clips connected with a carrier rail or strip. A pair of spaced-apart spring fingers are on the free ends of the clips for receiving an edge of a circuit-carrying board therebetween, and an elongate auxiliary support strand extends past the free ends of the plurality of clips and is mechanically connected with the free ends of the clips to provide support to the clips. According to another aspect of the invention, the clip has an angularly extending interconnecting portion between the stem end and free end, offsetting the free end in both a sideward and rearward direction relative to the stem end.

Abstract: A method for determining the extensibility of selected non-excised tissue of the uterine cervix, ear or skin by:(a) positioning the tissue between two force transmitting members, applying a varying compressive force to the tissue through the force transmitting members, measuring the force applied and the displacement of the non-excised tissue resulting from said force, and calculating the modulus of extensibility curve of the tissue, or(b) positioning the tissue between two force transmitting members, applying a constant compressive force to the tissue through the force transmitting members, measuring the displacement of the tissue resulting from the application of the force, and continuously monitoring the changes in the displacement of the tissue over a period of time to determine the changes in the extensibility of the tissue while the constant force is applied.

Abstract: An ultrasonic testing instrument and a method of non-destructive and non-invasive testing. The instrument and method employ a high intensity collimated ultrasonic beam. The collimated beam is achieved by means of acoustical lenses and/or reflectors.

Abstract: A cleaner which is particularly suited for use as a bilge cleaner comprises (a) methyl-2 pyrrolidone, (b) an alkylaryl polyether alcohol obtainable as the reaction product of octylphenol and ethylene oxide and containing an average of five ethylene oxide units per molecule, and (c) an alkylaryl polyether alcohol obtainable as the reaction product of octylphenol and ethylene oxide and containing an average of seven to eight ethylene oxide units per molecule. One or more of defoaming and color agents and a fragrance component are included in preferred embodiments of the invention.

Abstract: An improved process for dissolution of metals by etching, and particularly the etching of copper in printed circuit board processing or the like, using an aqueous H.sub.2 O.sub.2 --H.sub.2 SO.sub.4 etching solution, in which the concentration of H.sub.2 SO.sub.4 in the etching solution is allowed to decrease during use of the etching solution from an initial, relatively high level at the time the etching solution is put into use, to a final, relatively low level. When a predetermined concentration of dissolved etched metal exists in the etching solution, the etching solution is removed from use, H.sub.2 SO.sub.4 is added to increase the concentration of H.sub.2 SO.sub.4 in the etching solution to approximately the initial, relatively high level, and the metal is precipitated out of the etching solution.

Abstract: A control device for a discharge lamp, comprising an electronic switch connected between an AC supply source and a loading circuit including the discharge lamp to be controlled, and a control circuit delivering pulses to a control electrode of the switch so as to control the state of conduction thereof; the control circuit comprises means for detecting the passages through zero of the voltage at the terminals of the loading circuit and generating means responsive to the detecting means for generating pulses controlling the passage of the switch to the non-conductive state, whereby non-conduction periods of the switch are controlled for an adjustable duration in response to the passages through zero of the voltage at the terminals of the loading circuit.

Abstract: A lock-down mechanism for use with an exit door wherein an electromagnet on the door attracts an armature on the push rail when the latter is pushed to unlatch the door, the door being held unlatched as long as the electromagnet is energized.