Abstract: Methods and systems are described herein for an article of manufacture for use in a weapon sight wherein the article of manufacture comprises a passively charged photoluminescent material. When installed in a weapon sight, the passively charged photoluminescent material provides light to a fiber optic of the weapon sight during low light conditions to illuminate a reticle pattern of the weapon sight.

Abstract: Methods and systems are described herein for an article of manufacture for use in a weapon sight wherein the article of manufacture comprises a passively charged photoluminescent material. When installed in a weapon sight, the passively charged photoluminescent material provides light to a fiber optic of the weapon sight during low light conditions to illuminate a reticle pattern of the weapon sight.

Abstract: Methods and systems are described herein for an article of manufacture for use in a weapon sight wherein the article of manufacture comprises a passively charged photoluminescent material. When installed in a weapon sight, the passively charged photoluminescent material provides light to a fiber optic of the weapon sight during low light conditions to illuminate a reticle pattern of the weapon sight.

Abstract: Methods and systems are described herein for an article of manufacture for use in a weapon sight wherein the article of manufacture comprises a passively charged photoluminescent material. When installed in a weapon sight, the passively charged photoluminescent material provides light to a fiber optic of the weapon sight during low light conditions to illuminate a reticle pattern of the weapon sight.

Abstract: In an AC magnetic tracker one or more multi-axis field sources, each operating at a different frequency, or frequency set, are detected and tracked in three-dimensional space, even when wireless or otherwise not physically connected to the tracking system. Multiple sources can be tracked simultaneously as they each operate with their own unique detectable set of parameters. The invention not only provides the ability to uniquely identify one or more sources by their frequencies, but also to synchronize with these frequencies in order to measure signals that then allow tracking the position and orientation (P&O) of the source(s). Further, these sources need not be present at the time of system start-up but can come and go while being detected, discriminated and tracked. It also should be noted that application of such systems in multiples with more sensors not synchronized to a source or sources also could be employed to give the reverse appearance of a known source phase and incoherency with the sensors.

Abstract: Self-calibrating AC magnetic tracking systems and combination “outside-in” and “inside-out” architectures offer unique motion tracking capabilities. More area is covered with minimal distortion using the tracking system itself to determine overall P&O based on the P&O of an initial, reference marker. The output as anticipated and needed by the user is output without confusion and without costly and time-consuming metrology while covering a large region when distance from the reference may be great. A method according to the invention includes the steps of positioning a plurality of stationary AC magnetic “markers” in a tracking volume and moving a mobile AC magnetic marker proximate to a first one of the stationary markers designated as a reference marker. The position and orientation (P&O) of the mobile marker is determined relative to the reference marker, then moved so as to be proximate to a second one of the stationary markers.

Abstract: In an AC magnetic tracker one or more multi-axis field sources, each operating at a different frequency, or frequency set, are detected and tracked in three-dimensional space, even when wireless or otherwise not physically connected to the tracking system. Multiple sources can be tracked simultaneously as they each operate with their own unique detectable set of parameters. The invention not only provides the ability to uniquely identify one or more sources by their frequencies, but also to synchronize with these frequencies in order to measure signals that then allow tracking the position and orientation (P&O) of the source(s). Further, these sources need not be present at the time of system start-up but can come and go while being detected, discriminated and tracked. It also should be noted that application of such systems in multiples with more sensors not synchronized to a source or sources also could be employed to give the reverse appearance of a known source phase and incoherency with the sensors.

Abstract: A small, lightweight field source acts as a “pseudo-sensor” in an AC magnetic tracking system, facilitating wireless operation. Upon activation, the source sends out three continuous low-power magnetic signals, a separate frequency from each of three resonant orthogonal coils, without the need for switching to a receive mode or detecting a synchronizing signal to start the three signals simultaneously. This simple structure allows the source to be kept small and consume little power so that it can operate for over one hour before needing to be re-charged. This design approach thus allows a user or object being tracked to move about freely with no restricting cabling to a base station or even to a body-mounted electronics module and bulky battery. A family of frequencies can be used for each of several such pseudo-sensor sources in order for the base station sensors and electronics to track multiple sources.

Abstract: Techniques for removing distortion in an AC magnetic tracker identify a characteristic frequency in the distortion environment which is then utilized to extract distortion components from the tracker receiver signals so that the corrected position and orientation can be calculated. A multiplicity of alternative techniques for determining this characteristic frequency are disclosed, several of which can be done during operation without interrupting system operation while others can be done off-line. The invention also allows the use of a tuned tracker transmitter since it does not need to operate at multiple frequencies. The invention differs from the prior art by treating an extended conductor characteristic as just another unknown. The position and orientation algorithm solves the 6 unknown coordinates of position and orientation plus the one more unknown—the extended conductor characteristic frequency.

Abstract: A pelletising machine of the kind comprising an annular die having radial bores therethrough, and adapted to be rotated about its central axis, whereby material introduced into the centre of the die is extruded through the bores by the action of freely rotatable pelletising rollers which are closely spaced from the inner peripheral surface of the annular die, and having a door which can be hinged between an open position enclosing the die, there being a cut-off knife mounted on the end of a shaft extending through the wall of said door, characterised in that the shaft supporting the cut-off knife passes through a guide sleeve carried in a housing secured to the wall of the door, there being means to permit fine adjustment of the position of said shaft axially within said guide sleeve and means permitting said guide sleeve together with said shaft to be moved as a unit rapidly outwardly relative to said housing and returned inwardly to their initial position.