Abstract: A self-driven synchronous rectifier circuit (50) for a DC—DC power converter. The circuit comprises a primary transformer (16), a first synchronous rectifier (SQ1) coupled to the primary transformer (16), a second synchronous rectifier (SQ2) coupled to the primary transformer (16), an external drive circuit (18). The circuit (50) also comprises a plurality of switches (SQ3, SQ4) controllably coupled to second synchronous rectifier (SQ2). The external drive circuit (18) provides turn-off signaling for both synchronous rectifiers (SQ1, SQ2) Turn-on signaling provided for first synchronous rectifier (SQ1) by the primary transformer (16) turn-on signaling for second synchronous rectifier (SQ2) is provided by the external drive circuit (18).

Abstract: A push-pull converter for converting an input voltage to a selectable output voltage is disclosed. The push-pull converter includes a pair of primary switches and a pair of primary windings of a transformer. The voltage stress across the primary switches is regulated by means of a clamp capacitor. The clamp capacitor clamps the voltage of the primary switches during the reset of the primary windings of the transformer. An alternate embodiment is also disclosed in which the voltage stress across the primary switches is regulated by means of two clamp capacitors. The clamp capacitor clamps the voltage of the primary switches during the reset of the primary windings of the transformer. The clamp capacitors extend the transformer reset period to include the lagging dead time for the corresponding switches, as well as the complementary powering stage. Current in the output section during the dead times is permitted by means of an additional diode, therein.

Abstract: A rectifier circuit having voltage clamping circuitry is disclosed. The rectifier circuit includes a transformer having a primary winding and a secondary winding and transistor switches each being connected to an end of the secondary winding of the transformer. The rectifier circuit further includes a first diode having an anode terminal connected to a first end of the secondary winding and a second diode having an anode terminal connected to a second end of the secondary winding. The cathode terminals of the first and second diodes are coupled to a capacitor. The energy stemming from voltage spikes and/or high frequency ringing appearing at the transistor switches due to parasitic effects is effectively absorbed by the first and second diodes and collected in the capacitor. The collected energy is recycled to control the operation of the transistor switches.

Abstract: An external driving circuit (21) for a bridge type synchronous rectifier circuit (20) having a first and second first synchronous rectifier (Q3,Q4), a primary driving circuit (14), and a pair of totem pole drivers (16,18). The timing signal for the first and second synchronous rectifiers (Q3,Q4) is derived from the external driving circuit (21). The external driving circuit (21) includes a first and second switch drivers (22,24). The external driving circuit (21) is interfaced with the synchronous rectifier circuit (20) by connecting first and second switch drivers (22,24) to the totem pole drivers (16,18). The first and second switch drivers (22,24) provides storage for circuit current which is fully discharged at the appropriate time to facilitate turning on and off the synchronous rectifiers (Q3,Q4).

Abstract: A self-driven synchronous rectifier circuit (42) for a power converter. The circuit comprises a transformer (49, 70) having a secondary winding with a first and second terminal, a first synchronous rectifier (14) coupled to the second transformer terminal and having a control terminal, and a second synchronous rectifier (16) coupled to the first transformer terminal and having a control terminal. The circuit (42) also comprises a first switch (44) coupled to the first synchronous rectifier (14) control terminal, and a second switch (46) coupled to the second synchronous rectifier (16) control terminal. The first (44) and second switch (46) are also coupled to the secondary winding. Switching transitions of the first (14) and second (16) synchronous rectifiers are initiated by a polarity reversal of the voltage of the secondary transformer winding.

Abstract: A method for modifying the specificity or efficiency of an enzyme, while retaining its catalytic activity, is disclosed. The method is characterized by selecting an enzyme, the tertiary structure of which is substantially known or deduced; identifying a single specificity or efficiency-related region of the enzyme; identifying or constructing unique restriction sites bounding the identified region in the DNA coding therefor; generating a DNA sequence which corresponds to at least a portion of the identified region, except that the nucleotides of at least one codon are randomized, using the generated DNA sequence to replace the original such sequence; expressing the DNA including the generated DNA sequence; and selecting for a desired modification so that the DNA coding therefor may be isolated; the randomized DNA being generated by means of a PCR assembly method. Enzyme generated using this method, and having enhanced specificity or efficiency, are also disclosed.

Abstract: A tufting machine comprising a drive shaft, an eccentric rotatable by the drive shaft, a connecting member (6) mounted at its proximal end for rotation about the eccentric (4) and coupled at its distal end to pushing means (26) for pivotal movement in relation thereto, a needle mounting means associated, for reciprocating movement, with the said pushing means (26) which impart the reciprocation to the needle mounting means under the impulse of the connecting member (6). The connecting member comprises at least two parts, a distal part (22) for engaging the pushing means and an adjustable proximal part (24) for engaging the said eccentric, the adjustment being possible by varying the position of the proximal part with respect to at least a part of the said eccentric (4). The variation may be provided by a split eccentric with inward facing grooves (10, 12) on the two parts to vary the relative position and thus the focus of the eccentric may be varied without providing a replacement eccentric.

Abstract: This invention relates to a novel method of manufacturing a lyophilized suppository composition wherein said suppository is made in situ in an applicator cartridge.

Abstract: An apparatus and method for simulating a desired response in accordance with an external applied force. The apparatus includes a member which is responsive to the applied force, an actuator coupled to the member for exerting a torque on the member, a force sensor for detecting the applied force, and a torque sensor for detecting the torque exerted by the actuator. Signals from the force sensor are used to determine the system response based upon a desired relation. The force sensor signals also are used to determine the actual system response based upon the physical characteristics of the apparatus. The detected torque is compared with the desired and the actual system response, and as a result of the comparison the torque exerted by the actuator onto the member is adjusted accordingly so that the member performs the desired system response. The actuator is preferably an electric motor so that the apparatus can simulate any desired response, notwithstanding the physical characteristics of the system.

Abstract: An apparatus and method for simulating a desired response in accordance with an external applied force. The apparatus includes a member which is responsive to the applied force, an actuator coupled to the member for exerting a torque on the member, a force sensor for detecting the applied force, and a torque sensor for detecting the torque exerted by the actuator. Signals from the force sensor are used to determine the system response based upon a desired relation. The force sensor signals also are used to determine the actual system response based upon the physical characteristics of the apparatus. The detected torque is compared with the desired and the actual system response, and as a result of the comparison the torque exerted by the actuator onto the member is adjusted accordingly so that the member performs the desired system response. The actuator is preferably an electric motor so that the apparatus can simulate any desired response, notwithstanding the physical characteristics of the system.

Abstract: A computer base unit has a keyboard and computer peripherals. A removable workslate, capable of stand-along operation and containing a digitizer display, computer and rechargeable power supply attaches to the base unit through an interlocking connector that holds the workslate in a tilted position and connects the base unit and its peripherals to the workslate computer. The base unit and workslate comprise housings are constructed of a composite comprising layers of woven, resin impregnated fibers and a layer of electromagnetic shielding.

Abstract: An apparatus and method for simulating a desired response in accordance with an external applied force. The apparatus includes a member which is responsive to the applied force, an actuator coupled to the member for exerting a torque on the member, a force sensor for detecting the applied force, and a torque sensor for detecting the torque exerted by the actuator. Signals from the force sensor are used to determine the system response based upon a desired relation. The force sensor signals also are used to determine the actual system response based upon the physical characteristics of the apparatus. The detected torque is compared with the desired and the actual system response, and as a result of the comparison the torque exerted by the actuator onto the member is adjusted accordingly so that the member performs the desired system response. The actuator is preferably an electric motor so that the apparatus can simulate any desired response, notwithstanding the physical characteristics of the system.

Abstract: A modular computer system is disclosed that includes a self-contained work-slate unit having a housing comprising a dense layer forming an external surface of the housing, a first layer of woven structural fiber material overlaying the relatively high density layer, a layer of closed cell foam material overlaying the first layer of structural fiber material preferably woven, a second layer of woven structural material overlaying the layer of closed cell foam material, a layer of electro-magnetic shielding material overlaying the second layer of woven structural material and a third layer of woven structural fiber material overlaying the layer of electromagnetic shielding. The first, second and third layers of woven structural fibers, the layer of electro magnetic shielding and the layer of closed cell foam are permeated with a thermoset resin for binding the respective layers of the composite housing together.

Abstract: A doll including a body, the body being shaped to depict the body of a mermaid, a head, the body and head having generally hollow interiors, apparatus positioned within the body and the head for providing sound, and apparatus for activating the apparatus for providing sound.

Abstract: A quick drawing mechanism for use in an animated figure toy having a hollow torso and arm. A push button at the back of the torso is pushed causing a plate with rack to pivot and an arm connector having gears which engage the rack to rotate. Rotation of the arm connector causes the hollow arm to rotate upward and an upper member inside the arm to engage a stationary cam member mounted in the torso. The cam member causes the upper member to pivot which releases a lower member releasably held inside the hollow arm simulating a quick draw.

Abstract: A toy including a figure adapted to be moved slowly from a lowered position in which the figure is concealed behind a portion of a housing to a raised position in which the figure is visible and to be moved rapidly from its raised position to the lowered position. The mechanism moving the figure is driven by a music box and includes a post supporting the figure, a pin fixed to the post, an actuating arm having an aperture at one end in which the pin is loosely engaged and being secured to a housing at its other end. The means driven by the music box to cause the arm to reciprocate between the raised and lowered positions, also rotates the figure about a verticle axis.

Abstract: A toy including a base portion having a spherically contoured lower surface with a generally flattened portion at the center thereof and an upper surface with a centrally positioned post, and a plurality of other members, each of like configuration, but of different sizes, each being provided on the undersurface thereof with a centrally positioned cup-shaped socket portion configured for generally interlocking with the post, and on the upper surface thereof with a generally centrally positioned post. A figure member is provided with a cup-shaped socket portion in the bottom thereof for engagement with the post of the uppermost other member.

Abstract: A winding and launching device for toy vehicles which includes a base covered by a shell, the shell having a shaft projecting therefrom and being adapted to mate with a coupling on a flywheel-driven toy vehicle for rotating the flywheel. The shaft is rotated at high speed through a step-up gearing arrangement by a crank positioned on the shell. A button protrudes from the shell and is connected to a platform which holds the shaft in place, depressing the button pulls the shaft from the vehicle coupling so that the vehicle may speed away.

Abstract: The collector-emitter electrodes of each of two NPN transistors having the collector electrode of each direct current cross connected to the base electrode of the other are connected, respectively, across an operating potential source through a collector load resistor element and an active collector load element. A biasing circuit arrangement is effective upon each application of supply potential to activate the active collector load element a period of time later than that at which base-emitter drive current is initiated through the base-emitter junction of the NPN transistor having the collector-emitter electrodes thereof connected across the supply potential source through the active collector load element whereby this transistor is always triggered conductive first upon each application of supply potential.

Abstract: During the presence of a selected internal combustion engine operating parameter such as a coolant temperature range, the alternating current timing signals induced in the output coil of an electrical generator assembly having at least a rotor member rotated in timed relationship with the engine are overridden by the output signal of a circuit combination that produces the output signal during the positive going portion of each of the timing signals and maintains the output signal for a period of time that varies inversely in duration as the potential level with respect to ground of an engine speed variable potential signal varies directly with engine speed to provide an engine speed ignition spark retard that diminishes substantially linearly in value from maximum to minimum between selected first lower and second higher engine speeds.