Abstract: Folding propeller system for safe packing and shipping, and easy deployment.

Abstract: In an aspect, an apparatus includes a hovering unmanned aerial vehicle (HUAV). The HUAV includes an arm assembly configured to support a propeller in such a way that propeller drag of the propeller is decoupled from yaw torque requirements associated with the hovering unmanned aerial vehicle. In another aspect, an apparatus includes an HUAV that has an arm assembly that is field-foldable relative to the HUAV between a flight-ready state and a folded state. In another aspect, an apparatus includes an HUAV having an arm assembly that is keyed in such a way as to facilitate field-assembly relative to the HUAV.

Abstract: Folding propeller system for safe packing and shipping, and easy deployment.

Abstract: In an aspect, an apparatus includes a hovering unmanned aerial vehicle (HUAV). The HUAV includes an arm assembly configured to support a propeller in such a way that propeller drag of the propeller is decoupled from yaw torque requirements associated with the hovering unmanned aerial vehicle. In another aspect, an apparatus includes an HUAV that has an arm assembly that is field-foldable relative to the HUAV between a flight-ready state and a folded state. In another aspect, an apparatus includes an HUAV having an arm assembly that is keyed in such a way as to facilitate field-assembly relative to the HUAV.

Abstract: The invention provides a hovering aerial vehicle with removable rotor arms and protective shrouds. Removing the shrouds reduces the weight of the vehicle and increases flight time. Removing the rotor arms makes the vehicle easier to transport. Removable rotor arms also simplify field repair or replacement of damaged parts.

Abstract: The invention provides a hovering aerial vehicle with removable rotor arms and protective shrouds. Removing the shrouds reduces the weight of the vehicle and increases flight time. Removing the rotor arms makes the vehicle easier to transport. Removable rotor arms also simplify field repair or replacement of damaged parts.

Abstract: In one aspect, an electronic association is maintained between each order received at a place at which goods or services are offered, the goods or services to be delivered at a point in the place, and the association of the order with the delivery place is enabled to be altered between the time when the order is placed and the time when the order is delivered.

Abstract: A system for detection of smoke by measuring changes in the contrast of a multi-contrast target disposed remotely from a photoelectric sensor. The obscuration of the detection path causes a reduction in the contrast of the sensed target, and a change of predetermined magnitude is employed to trigger an alarm. The target has one or more relatively darker and one or more relatively lighter areas which are viewed by the sensor. The sensor can be composed of a plurality of photosensors each viewing a respective area of the target. Or, the sensor can be a single scanning sensor such as a video camera. Only a single line or segment of a line of the video frame pattern need be employed to monitor the target. The video camera can be employed on a shared basis for providing smoke monitoring and detection, together with other functions, such as intrusion detection, access control, or visual surveillance of an area.

Abstract: For use in an alarm system, a security switch is provided, the transition state of which is detected by an associated circuit and a coded signal transmitted along a communication path indicative of the transition state, this coded signal being received and decoded to provide an output indication of the switch state.

Abstract: An electronic sounder employs a pair of piezoelectric oscillators tuned to different frequencies to provide loud raucous sound. The sounder is especially suited for providing audible indications of an alarm condition which is sensed by an associated alarm system.