Abstract: A symmetrical ac power system provides a balanced ac output, whose maximum voltage with respect to a reference ground potential is one-half the ac output voltage, and which is derived from a single phase ac source through the use of an isolation transformer having a center-tapped secondary winding. The center tap is connected to the output power load circuit as a ground reference potential with respect to the symmetrical ac output so as to constitute the reference ground potential for the power supply and load. Since symmetrical ac power is applied to the load by the system, reactive load currents, other power artifacts, EMI and RFI emissions and other interference and noise components ordinarily resulting from the application of conventional ac power to the load are reduced or eliminated by appearing as equal inversely phased signal elements which cancel one another. In order to maximize the performance of the symmetrical power system, the isolation transformer has a bifilar-wound secondary winding.

Abstract: A blind cord safety device for use in controlling an adjustable blind having a looped control cord and a looped control chain by enclosing the loops has housing within which are disposed a rotatable wheel adapted to engage the chain loop thereabout and a U-shaped cord loop receiver adapted to receive the cord loop in a peripheral groove formed thereon. The receiver is mounted within the housing so as to permit limited longitudinal but not lateral movement of the receiver within the housing. A spring is disposed within the housing between the receiver and the housing top so as to normally urge the receiver away from the housing top so as to avoid slack in the cord as a result of the cord stretching over time as a result of use.

Abstract: A symmetrical ac power system provides a balanced ac output, whose maximum voltage with respect to a reference ground potential is one-half the ac output voltage, and which is derived from a single phase ac source through the use of an isolation transformer having a center-tapped secondary winding. The center tap is connected to the output power load circuit as a ground reference potential with respect to the symmetrical ac output so as to constitute the reference ground potential for the power supply and load. Since symmetrical ac power is applied to the load by the system, reactive load currents, other power artifacts, EMI and RFI emissions and other interference and noise components ordinarily resulting from the application of conventional ac power to the load are reduced or eliminated by appearing as equal inversely phased signal elements which cancel one another. In order to maximize the performance of the symmetrical power system, the isolation transformer has a bifilar-wound secondary winding.

Abstract: A dental floss holder is provided with a slot-headed locking axle on which a spool of floss is mounted. A length of floss from the spool disposed within the holder passes through the axle slot and is spanned across two spaced prongs formed on the holder and locked to the axle by being wound on the axle beneath the slotted head after spanning. Tension is selectively manually applied to the spanned floss by the unidirectional rotation of locking cap which is held in position by the slotted head of the locking axle to provide a taut span of floss which can be manipulated between the user's teeth.

Abstract: A valve for medical use has a cannula mounted on a hub and fixed in a fluid conduit so that the cannula points upstream. An elastomeric valve element is mounted on the hub within the conduit so as to enclose the cannula. The valve element has a first solid portion of circular cross-section disposed upstream of the cannula point which closes the conduit, a second hollow frustoconical portion within which the cannula point is disposed, and a third hollow cylindrical portion surrounding the cannula downstream from its point and fixed to the hub. The second portion has a frustoconical interior passageway. In use, the valve element is compressed by application of a medical appliance to the valve element first portion to cause the cannula point to pierce the first portion to provide a path for fluid flow through the conduit.

Abstract: A valve for medical use has a cannula mounted on a hub and fixed in a fluid conduit so that the cannula points upstream. An elastomeric valve element is mounted on the hub within the conduit so as to enclose the cannula. The valve element has a first solid frustoconical portion upstream of the cannula point, a second hollow frustoconical portion within which the cannula point is disposed, and a third hollow cylindrical portion surrounding the cannula downstream from its point and fixed to the hub. The second portion has a frustoconical interior passageway tapering inwardly from the first portion toward the hub. A supplementary metallic frustoconical sleeve is fixed within the second element interior so as to open outwardly toward the first element and enclose the cannula point. In one type of use, the valve element is compressed to cause the cannula point to pierce the first portion to provide a path for fluid flow through the conduit.

Abstract: A dental floss holder is provided with a slot-headed locking axle on which a spool of floss is mounted. A length of floss from the spool disposed within the holder passes through the axle slot and is spanned across two spaced prongs formed on the holder and locked to the axle by being wound on the axle beneath the slotted head after spanning. Tension is selectively manually applied to the spanned floss by the unidirectional rotation of locking cap which is held in position by the slotted head of the locking axle to provide a taut span of floss which can be manipulated between the user's teeth.

Abstract: A dental floss holder is provided with a slot-headed locking axle on which a spool of floss is mounted. A length of floss from the spool disposed within the holder passes through the axle slot and is spanned across two spaced prongs formed on the holder and locked to the axle by being wound on the axle beneath the slotted head after spanning. Tension is applied to the spanned floss by rotating a locking flange which is held in position by the slotted head of the locking axle to provide a taut span of floss which can be manipulated between the user's teeth.

Abstract: A plug type electrical termination for a multiple conductor armored electrical cable having a hollow connector head filled with high temperature tin-based solder. The electrical conductors pass into one end of the head and extend out the other end through individual bores formed in a cylindrical plug portion, terminating beyond the plug portion in threaded conductor tips, to which conductor terminals are attached. The portion of each conductor within each bore is enclosed in a preselected one of several embodiments, in which the conductor insulation may or may not extend through the bore. In certain embodiments, the individual conductors are enclosed by silver-plated metallic sheaths.

Abstract: An earring jacket has a connecting member having a bore therethrough at one end to receive attaching means for attaching the connecting member to a human ear and an ornamental member pivotally connected to the connecting member so that the ornamental member, when so connected, pivots with respect to the connecting member about an axis transverse to the axis of said bore so that the ornamental member hangs vertically from the ear.

Abstract: A medical device which presents the backflow of fluid therethrough is particularly useful as a bloodless catheter assembly, that is, prevents the backflow of blood through the catheter by utilization of a self-closing valve carried in a hollow catheter housing to one end of which a catheter is fixed so as to provide a fluid passage through the catheter and catheter housing. The fluid passage in the catheter housing is sealed by a self-sealing valve element extending transversely across the passage upstream from the catheter. A hollow needle is held in the catheter housing downstream of and pointed at the valve element. Attachment of a fluid dispensing medical appliance to the other catheter housing end forces the valve element downstream onto the needle so as to pierce the valve element and open a fluid passage from the catheter housing upstream of the valve element through the hollow needle to the catheter.

Abstract: A retractable intravenous needle assembly wherein a cannula is mounted on a hub within an interior passage formed in a housing in which the cannula and hub are slidably mounted so as to have the cannula point manually extend beyond the housing. Flexible wings extending laterally from the housing are manually folded upwardly to release a locking stop formed in the interior passage from engaging a locking lug on the hub. The cannula point is then manually retracted into the housing until the locking lug engages a locking recess formed in the interior passage to lock the hub in the housing. The locking recess is so located in the passage that the housing completely encloses the cannula point when the locking lug is locked in the locking recess, thus facilitating handling and disposal of the used assembly without endangering hospital personnel.

Abstract: A blood collection device wherein a double-ended cannula is retracted within the barrel of the device for storage and disposal. The cannula is attached to the device immediately prior to use by being threaded into an aperture formed in a movable disc disposed within the barrel and rotated to a locked operating position for attachment of the cannula and use. After use, the disc is counter-rotated to permit the cannula, mounted to the disc, to be longitudinally retracted completely within the barrel to a position in which the cannula is permanently locked by stopping the disc against further movement. The disc aperture is threaded in the same direction as it is rotated to the operating position to avoid moving the disc out of the locked position during attachment of the cannula to the device.

Abstract: A method for determining orthodontic bracket placement on a malocclused tooth to correct the malocclusion includes the steps of generating digital information which defines the shape and location of the malocclused tooth in the patient's jaw, from which digital information a mathematical model of the tooth and jaw is generated. The correct placement position of a bracket is then calculated from the digitized information. A standard bracket is thereafter modified, if desired, individually for the patient, in view of the patient's physical deviations from the statistical averages. The shape of a bracket positioning jig is calculated and formed. Another step is forming an archwire for the brackets. The method may be used on one or more teeth in the same dental arch, as well as for both dental arches with respect to malocclusion therebetween.

Abstract: A blood collection device wherein a double-ended cannula is retracted within the barrel of the device for storage and disposal. The cannula is mounted on a first disc which is connected to a second axially aligned disc by a pair of string-like flexible members which are operable, when the second disc is moved away from the first disc, to retract the cannula completely within the barrel to a position in which the cannula is permanently locked by stopping the first disc against further retractive movement and the second disc against movement toward the first disc.

Abstract: A catheter inserter has an inserter housing with a flat base and a cannula housing disposed within the inserter housing with a cannula extending generally parallel to the inserter housing longitudinal axis. Stop means are disposed at each end of the inserter housing. locking means on the cannula housing selectively engage the stop means to lock the cannula housing in a first disposition in which the cannula extends outwardly from the inserter housing and in a second disposition in which the cannula is retracted within said inserter housing. The cannula housing has a passage in fluid communication with the cannula which, together with means on the inserter housing and cannula housing, permit the external viewing of blood passing into the fluid passage from the cannula.

Abstract: A blood collection device wherein a double-ended cannula is retracted within the barrel of the device for storage and disposal. The cannula is attached to the device immediately prior to use by being threaded into an aperture formed in a movable disc disposed within the barrel and rotated to a locked operating position for attachment of the cannula and use. After use, the disc is counter-rotated to permit the cannula, mounted to the disc, to be longitudinally retracted completely within the barrel to a position in which the cannula is permanently locked by stopping the disc against further movement. The disc aperture is threaded in the same direction as it is rotated to the operating position to avoid moving the disc out of the locked position during attachment of the cannula to the device.