Abstract: A frequency converter is provided for a three-phase electric motor and has input connections for a multi-phase alternating current electric supply source, and output connections for connection to a three-phase electric motor. A SCR bridge including a plurality of SCRs interconnects the input connections and the output connections. A trigger circuit is connected to the SCR bridge for selective firing of the SCRs, in response to timing pulses generated upon zero crossing of the input means phases. Logic circuits interconnecting said timing pulse generators and the trigger circuits for effecting selective sequential firing of the SCRs at the zero crossings. Firing of said SCRs is respectively terminated by natural commutation. In one embodiment of the invention single phase current is converted to multiphase current.

Abstract: Apparatus for the non-invasive disintegration of kidney stones and the like. An ellipsoidal reflector open at one end is positionable against the body, and may have a diaphragm across the opened end to prevent leakage of water contained in the reflector. A spark gap is located at the first focal point of the ellipsoid, and sonic aiming means is physically interconnected with the ellipsoid for aiming the ellipsoid at the kidney stone or the like to locate the kidney stone at the second focal point of the ellipsoid. A series of sparks discharged across the spark gap generates a succession of shock waves that travel through water in the reflector, and through the body to impinge on the kidney stone or the like and thereby to disintegrate the same.

Abstract: Apparatus is provided for the extracorporeal disintegration of kidney stones and the like. An ellipsoidal reflector has a spark gap positioned at one focus point of the ellipsoid, and the reflector is positioned so that the kidney stone being disintegrated is at the second focus point. The reflector is filled with water so that when a spark is generated through the spark gap, a shock wave is generated through which is focused through the water and through body tissues on the kidney stone. Both an electrocardiogram apparatus and an ultrasound pick-up apparatus are coupled to a spark triggering circuit controlling the pulse generator so that a spark or pulse can be generated only during ventricular contraction, thereby avoiding any possibility of inducing fibrillation of the heart.

Abstract: A balance-type scale is provided which is made nearly substantially entirely of plastic, thereby being resistant to environmental degradation. A counter-balance weight is of metal, but is embedded within the plastic. The scale is of two-part construction, comprising a body including the counter weight and a hook-like structure at the opposite end. A suspension member is pivotally connected to the body, and comprises a pair of spaced plates embracing the body. The suspension member includes a pointer, and the body is provided with indicia to be read opposite the pointer and readable directly in units of weight.

Abstract: A disposable electrode pad is provided for a defibrillator electrode. The pad is saturated with electrically conductive greasy material, sometimes known as electrogel. The pad is designed for adhesive or other securing to the electrode, and the pad is covered with a tear-off aluminum sheet cover to protect the integrity and sanitation of the pad, while still allowing sufficient electrical conductivity for monitoring a patient's heartbeat through the electrode.

Abstract: A dog brush is provided for attachment to a conventional vacuum cleaner. Semi-flexible plastic bristles are curved in the direction in which the brush is drawn across a dog, whereby to cradle loose hairs transversely of the air flow into the vacuum cleaner, and thus most efficiently to pull the loose hairs into the vacuum cleaner. Restrictive orifices are provided to increase velocity of air flow further to facilitate picking up loose hairs. The handle of the brush is oriented for most efficient brushing of a dog.

Abstract: Electronic defibrillating mechanism in which the electrodes comprise handles to be grasped by an operator with electrodes in the form of discs to be placed against the chest of the patient. The handles are provided with push buttons, and a neon ready-light is provided in each push button to indicate when the apparatus is charged to the desired extent for the operator to effect a defibrillating discharge.