Abstract: A bench vice comprises a fixed jaw and a moveable jaw, both sliding on a slide bar. The jaws are made of plastics material and are supported against pressures imposed by the slide by pins retained in the jaws. One of the pins on the fixed jaw is knurled to provide a jamming function against the slide. The moveable jaw has a knob screwed onto a block fixed on the slide, so that rotation of the knob advances the moveable jaw along the slide, or releases it.

Abstract: A forward converter circuit that includes elements capable of generating a zero volt switching (ZVS) signal across the power switch. The ZVS generating elements include a series combination of a switch and shunt inductance, which are connected in parallel across the primary winding of the power transformer. An offset capacitor is placed in series with the shunt inductance and is operated in conjunction with a control circuit to couple the magnetizing current from the primary winding of the power transformer and use it to charge the offset capacitor. This provides zero volt switching of the power switch at turn-on and turn-off, and reset of the core of the power transformer without the use of a tertiary winding. The circuit also achieves added protection of the power switch without the use of an active clamp.

Abstract: Effective harmonic correction without frequency, power or voltage limitations is achieved in a single-stage DC-to-DC converter by disconnecting the bulk capacitor of a typical single-stage converter during low voltage conditions, and by using various phase and cycle modulation techniques associated with a switchable auxiliary transformer winding which charges the bulk capacitor to control its voltage. A means is thus provided to control the level of harmonics generated depending upon the level of the AC output voltage. When the auxiliary winding is used as a clamp winding, full ZVS conditions are provided for both the auxiliary winding switch and the converter's primary winding switch. Energy can then also be directed, under independent control of the switched auxiliary winding, to independent power nodes, i.e., either the output capacitance and load, or the bulk capacitor. This ensures that the output voltage will not be affected during any period needed to recharge the bulk capacitor.

Abstract: A continuous mode flyback converter circuit which includes elements capable of generating a zero volt switching (ZVS) signal across the power switch. The ZVS generating elements include a switched shunt inductance coupled in parallel with active clamp components and connected across the primary winding of the power transformer. The circuit reduces the reverse recovery current through the secondary stage rectifier and the current through the active clamp switch during operation of the converter. The ZVS generating elements may also be used for flyback converters which do not utilize an active clamp.

Abstract: A boost converter circuit which includes elements capable of generating a zero volt switching (ZVS) signal across the power switch. The ZVS generating elements include a switched shunt inductance which is referenced to the positive rectified supply voltage instead of to the output voltage as with other ZVS techniques. This causes a reduction in the inductance value required for generating the ZVS signal, and a resulting reduction in the power loss associated with operation of the converter. The inventive circuit permits operation of the boost converter using high frequency FET devices or slower switching insulated gate bipolar junction transistors as the power switch.

Abstract: A thermally regulated power system, where the extent to which the temperature of a power module causes a change in the output power of the module depends on the output current of the module. Similarly, the extent to which the output current of the power module causes a change in the output power of the module depends on the temperature of the module. In one embodiment, a thermally regulated down slope power sharing system without a share line includes N+1 power modules coupled in parallel to the same output port, where N is an integer greater than one. The slope of the down slope curve of a power module is changed in response to the temperature of the power module such that a power module operating at a higher temperature outputs less current for a given bus voltage than a power module operating at a lower temperature.

Abstract: A blood collection device has a modular suction regulator assembly in the form of an adjustable negative pressure relief valve which controls the level of suction in a collection chamber by admitting air to a short bleed-in passage proximate to a suction connection. The modular assembly is a canister which drops into a receptacle oriented transversely in the collection vessel, and defines a laterally-directed intake manifold which resists blockage. The intake passes centrally through the canister along a path spanned by a filter, past a hat-shaped poppet supported on a compression spring. Fluted and threaded members control the scale and range of poppet response so that the assembly may be calibrated before installation. A face plate covers the installed canister, and radial vanes in the intake manifold double as gripping elements for manual adjustment of the assembly. A bellows meter provides refined suction resolution by linearly advancing across an oblique or curved reference line.

Abstract: An interleaved flyback electrical power converter system having a plurality of flyback power converters operated in continuous mode, each converter utilizing a power switch operated under zero voltage switching conditions. The interleaved flyback power converter system is highly efficient and compact, and is suitable for use in high power, high frequency applications.

Abstract: A transient voltage protection circuit includes a normally closed switch connected between a rectifier circuit and a DC to DC converter. This switch is caused to switch to a current limit state when the voltage input to the DC to DC converter exceeds a first predetermined value, thereby protecting the DC to DC converter from voltages that exceed the converter's operational limits. The switch is returned to its normally closed state when the voltage input to the converter drops below a second predetermined lower value. A capacitor connected across the input terminals of the converter is charged up when the switch is closed and functions to supply power to the DC to DC converter when the switch is in its current limit state.

Abstract: An information display apparatus, such as a lectern (6), is disclosed which is usable when giving a presentation or speech. The lectern includes a screen (2) for the display of text and a memory for the storage of text to be displayed. Also included is a controller (9) for controlling the text displayed on the screen in response to the operation of a keypad. The lectern includes a transmitter such as an infrared diode for the actuation of a further piece of apparatus such as a projector (54) or an audio system.

Abstract: An electrical power converter system having a power factor correction circuit and a switching power converter. The power factor correction circuit converts the AC line voltage into an unregulated DC voltage referred to as the PFC voltage, which supplies an unregulated DC input voltage to the switching power converter. The switching power converter converts the unregulated DC input voltage into one or more regulated DC output voltages. The PFC voltage automatically adjusts to an appropriate value for achieving the desired power factor correction, converter efficiency, and converter temperature. In a preferred embodiment, the value of the PFC voltage is adjustable in response to a control signal produced by a PFC control circuit. The PFC control circuit measures the peak value of the input line current to determine whether the power factor is acceptable. If the power factor is acceptable, the PFC voltage will be maintained at a relatively low value.

Abstract: Size reduction in a clamped power converter can be achieved, and stability of the converter under no-load and transient loads can be substantially improved, by operating the converter in a continuous flyback mode.

Abstract: A device to facilitate the use of extraction discs used in analysis of water impurities includes a cylindrical body with a top cavity to receive the extraction disc with a threaded ring holder to hold an open bottom container sealed on the extraction disc with a valve to selectively channel flow from the extraction disc into three downward passages, two of which open through the bottom into wash and elute sample containers and a third to a tube that opens into a large collection container sealably attached to the bottom of the body around the smaller containers with a vacuum passage through the bottom of the body into the large container controlled by a valve. The body has two parallel slots On opposite sides of the body to engage into cut outs of a rack panel supported above a housing with a slanted top wall with elliptical holes cut to receive the collection container and support it sticking out of the housing.

Abstract: A fluid collection vessel for drainage of body fluids includes a molded body with internal dividers constituting ports, baffles and subchambers, and a face plate that closes the body to form a suction-regulated multi-chamber vessel. The vessel has overpressure and underpressure protection, and cannot lose its fluid when tipped. The molded body incorporates novel valves and ports, and a wall structure enhances its utility for blood collection and monitoring. Dynamic fluid level is stabilized by diversion of fluid energy into a side chamber in the downstream region of the manometer column.

Abstract: A collection vessel for drainage of body fluids includes a molded body with internal dividers constituting ports, baffles and subchambers, and a face plate that closes the body to form a suction-regulated multi-chamber vessel. The vessel has overpressure and underpressure protection, and resists tipping. The molded body includes a wall structure that enhances its utility for blood collection, monitoring, and reinfusion, and incorporates novel valves, ports, handle and stand.

Abstract: A device to facilitate the use of extraction discs used in analysis of water impurities includes a cylindrical body with a top cavity to receive the extraction disc with a threaded ring holder to hold an open bottom container sealed on the extraction disc with a valve to selectively channel flow from the extraction disc into three downward passages, two of which open through the bottom into wash and elute sample containers and a third to a tube that opens into a large collection container sealably attached to the bottom of the body around the smaller containers with a vacuum passage through the bottom of the body into the large container controlled by a valve. The body has two parallel slots on opposite sides of the body to engage into cut outs of a rack panel supported above a housing with a slanted top wall with elliptical holes cut to receive the collection container and support it sticking out of the housing.

Abstract: An ostomy bag has a non-adhesive filter formed by a carbon fabric disc with impermeable layers on the front and back surfaces. The front layer has a central aperture whereas the rear layer is imperforate. The filter is releasably secured to an adhesive area around a vent opening of the bag with the aperture aligned with the opening so that gas can flow into the filter and radially outwards. The filter be peeled off and reversed to block escape of gas from the opening.

Abstract: In a matrix array for the supply of an electrographic stylus writing apparatus, a plurality of styli are driven by short pulses through R/C networks. The styli are divided into subgroups and parallel capacitors connect the styli of each subgroup to a high voltage switch which is responsive to a capacitor pulse driver. Each stylus is also driven through a resistive line which completes the R/C circuit. The resistive lines are connected in parallel for similar styli of each group to a resistor enable pulsing circuit and all resistive lines are connected via isolation diodes to a resistor reset means. In operation, a short pulse from the capacitor driver circuit is applied to all the capacitors of a single group and an enabling pulse is applied to a predetermined single resistive line of each group so that the combined, enabled R/C circuit for a single stylus within one of groups is activated.