Abstract: A shield for hypodermic needles is disclosed which is preferably of unitary construction and made of a plastic such as polypropylene. The shield is preferably cylindrical and is formed as a sleeve with a hollow bore for receiving the cannula of a hypodermic needle assembly. The shield is fixed at the hub of the needle assembly and can be either attached to the hub using a method such as heat or sonic sealing, or it can be manufactured with the hub as a unit. The sleeve has an upper axially rigid portion toward the tip end of the cannula, a lower axially rigid portion at the hub end, and at least two displaceable portions between the upper and lower rigid portions. Each of the displaceable portions are further subdivided into at least two subportions by introducing slits into the displaceable portions. The sleeve has hinging portions at the interfaces between the rigid portions and the displaceable portions, and a hinging portion at the interface between the displaceable portions.

Abstract: A method and apparatus are shown for generating and transmitting very short and widely separated high frequency sine-wave pulses of electromagnetic energy into space. A transistor, a charging capacitor, and an inductor are coupled into a first series loop path to form a discharge circuit. A bias voltage source, the same charging capacitor, and a charging resistor are coupled into a second series loop path to form a recharging circuit. The bias voltage source is selected to be capable of biasing the forward conduction path of the transistor near its breakdown condition. An original information signal is sampled upon each occurrence of a periodic reference signal, and the transistor is then triggered into its breakdown or avalanche mode. The starting times of successive transmitted pulses are modified in accordance with a pulse position modulation protocol.

Abstract: A reversible hand operated rotary power tool contains an internal mechanism for reducing the reaction torque that would otherwise be exhibited directly upon the housing, and hence imposed upon the hand of the operator. The mechanism is bidirectional, and reduces reaction torque to the same extent whether the tool is being operated in a forward direction or in a reverse direction. The mechanism includes a planetary differential mechanism having an input driven from a powered rotor, one separate output that is drivingly coupled to an output shaft, and another separate output that is drivingly coupled to an offset shaft that is laterally offset from the axis of the powered rotor. A lever system is employed to inhibit rotation of the offset shaft in either direction relative to the housing and thereby reduce reaction torque exhibited on the housing.

Abstract: A humbucker pickup for creating electrical signals indicative of the string vibrations of an electric guitar includes a matched pair of elongated coil assemblies and a transversely polarized permanent magnet disposed between and parallel to the coils. Each coil assembly includes a flat vertically oriented core plate which is reduced to partial height in one portion of its length. The core structures are disposed parallel to each other but with the partial height portions of the core plates at opposite ends of the respective core structures. Under each string of the instrument the full-height portion of one core plate forms a tall pole piece adjacent the string for concentrating the magnetic field through the string, while the reduced-height portion of the other core plate forms a short pole piece spaced away from the string.

Abstract: A brake assembly is universally mountable to any one of several different types and sizes of hand trucks. The complete brake assembly includes a brake control handle that is removably attached to the upper frame of the hand truck; a brake bar assembly having a base removably attached to the axle of the hand truck, and a horizontally extending brake bar with brake pads on its two ends adapted to engage the wheels; a cam mechanism for depressing the brake bar; and a cable coupling the brake control handle to the cam mechanism.

Abstract: A feed forward cancellation amplifier system for amplifying radio frequency telephony signals, including a main amplifier, an error correction circuit producing a message error signal, an error amplifier for producing an amplified message error signal that is then subtracted from the amplified and distorted message signal output of the main amplifier prior to a final output circuit, a negative feedback circuit responsive to a test signal for compensating and minimizing variation or drift in the operation of the error amplifier, the error correction circuit including a vector modulator responsive to modified quadrature vector components of the message error signal for producing a single voltage vector error signal, and the negative feedback circuit including an I & Q network for modifying the quadrature vector components of the error signal in the error correction circuit.The preferred form of the invention utilizes PIN diodes to provide voltage controlled attenuators in the vector modulator.

Abstract: A method of processing fruit, such as oranges, in which different chemical treatments are applied to different output streams of fresh fruit by passing the fruit in a continuous flow to an electronic grading apparatus having a single input but a plurality of separate and parallel outputs, and applying different chemical treatments to the continuous streams of fruit received from the different parallel outputs. This method permits a complete flexibility for optimizing treatment of various different grades of fruit that are intended to be sold as fresh fruit, or for different batches of the same grade that are intended for different markets. A particular advantage is that fruit intended for use in byproducts may be processed without any chemical treatment at all.

Abstract: A finger-mounted, rotatable slide for a stringed musical instrument includes a finger ring adapted to be received on one of the player's fingers, a rigid rail attached to a point on the circumference of the ring and extending from the ring in a direction perpendicular to the plane of the ring, and a finger tab provided on the rail. One longitudinal edge of the rail is straight, for engaging the strings, and the finger tab is on the other longitudinal edge of the rail. The player of the instrument mounts the ring on a finger, and applies an adjacent finger to the tab to selectively rotate the ring so as to either engage the straight edge of the rail with the strings, or disengage the rail from the strings.

Abstract: A non-reusable, disposable syringe has a cylindrical barrel with a needle assembly on its forward end, and a needle trap for protecting the needle from contact. The needle trap includes a hollow plastic housing with a rearward end portion adapted to fit over the cylindrical barrel, and a generally cone-shaped forward end portion having a closed forward extremity. A locking member of generally hollow cylindrical shape is secured within the rearward end of the needle trap housing and has forwardly directed flexible, circumferentially spaced, inwardly tapering fingers that taper inwardly more rapidly than the forward end of the housing when the needle trap is placed over the barrel the fingers of the locking member flex outwardly to pass over the needle base and then flex inwardly to assume a locking position behind the needle base.

Abstract: A prefabricated tooth replacement assembly includes a cap adapted to be secured upon an abutment, a replacement tooth for occupying a void in the patient's mouth, and an interlock for supporting the replacement tooth from the cap in a selected position of adjustment relative thereto. The interlock is provided by forming an opening in the replacement tooth, forming a lateral protrusion on the cap, and selecting the configuration of the parts such that the protrusion from the cap frictionally engages the opening in the replacement tooth. Further, the replacement tooth is made at least partially hollow, and the protrusion from the cap extends into its hollow interior and is then locked in place by bonding material filling the hollow interior.

Abstract: An eye bolt for a bicycle cantilever brake system is modified by the enlargement of the shoulders of the head, so that they no longer set within the contoured adjustment washer and the addition of a device to hold the brake shoe stud within the eye. Generally this device would include a threaded hole oriented transversely to the eye and a cooperative set screw. This combination allows the brake shoe stud to be held firmly in place in the eye shaft. With this configuration, the brake shoe may be replaced or adjusted without undoing the nut which retains the eye bolt, thereby allowing the firm retention of the contour adjustment washers during the operation.

Abstract: A variable displacement engine includes a rotatable crankshaft having a journal, a cam having an eccentric opening that receives the crankshaft journal, a piston rod assembly having one end journalled on the eccentric cam, and the cam also having an arcuately extending cavity that has gear teeth formed in its outer wall that are at a constant radius distance from the radial center of the eccentric opening, and a gear wheel disposed within the cavity and engaging the gear teeth for selectively adjusting the angular position of the cam relative to the crankshaft journal.

Abstract: An improved air ionizing apparatus that may be used as part of an air filtering system. The apparatus consists of an air passageway with at least one negatively charged ionizing member therein and a conductive strip, positively charged with respect to the ionizing member extending around at least a major portion of the interior periphery of the outlet of the passageway. The conductive strip attracts the negative ions, causing them to disperse as air directed down the passageway propels them toward and through the outlet of the passageway.

Abstract: An extendible multi-frame stand includes at least three frames arranged in a telescoping relationship, having a single coherent alignment and locking mechanism which includes alignment means for preventing relative rotation between the first and second frames, alignment means for preventing relative rotation between the second and third frames, means for locking the second and third frames at the limits of their longitudinal extension positions, and cam-operated releasable locking means for controlling extension and retraction of the second and third frames relative to each other and to the first frame.