Abstract:
A drive mechanism (16A, 16B) including a rotary actuated motor (18) configured to rotatably drive a drive arm (24) between a first position to a second position and an actuator (30) responsive to movement of the arm, wherein the actuator is thermally isolated from the arm in both the first position and the second position to create a thermal barrier. The drive arm is configured to engage and advance the actuator between the first position and the second position, while remaining physically spaced from the actuator in the first position and the second position. The drive arm includes a recess (26) such as an opening, wherein the actuator has a member (30, 34) configured to reside in the recess and remain thermally isolated from the arm in both the first position and the second position. In one preferred embodiment, a shutter (14) of an imaging device (10) is positioned in response to the actuator, which shutter remains thermally isolated from the motor and arm. Other devices may be driven as well, such as switches.
Abstract:
A drive mechanism (16A, 16B) configured to drive a thermally isolated actuator (30) between two positions. The drive mechanism includes a rotary actuated motor (18) configured to rotatably drive a motor member (20), and a drive member (22) coupled to the motor member and having a drive arm (24, 42) configured to responsively move from a first position to a second position upon rotation of the motor member. An actuator (30) is responsive to movement of the drive arm (24) moved from the first position to the second position. A drive circuit (60) is configured to generate a pulse width modulated (PWM) drive signal (70) configured to controllably drive the motor, the PWM drive signal having a first duty cycle (Phase 1) configured to advance the drive arm from the first position, and having a second duty cycle (Phase 2) different than the first duty cycle as the drive arm approaches the second position. The drive signal may be removed (Phase3) before the drive arm (42) engages a hard stop (54). The drive mechanism may comprise at least one sensor (40) configured to determine a position of the drive arm (42) proximate the first position and proximate the second position. The actuator is thermally isolated from the drive arm (42) in both the first position and the second position.
Abstract:
A detector apparatus (10) is provided and includes a collector (20) having access to a sample of a gaseous fluid and a tester (40) coupled to and disposed remotely from the collector (20). The tester (40) includes a test chamber (41) into which a sample is directed from the collector (20), an excitation element 43, such as a laser, to excite the sample in the test chamber (41) and a spectrum analyzing device (44), such as a spectrometer, coupled to the test chamber (41) to analyze the excited sample, and preferably to generate a plasma or filament, for evidence of a concentration of particles of interest, such as isotopic molecules, in the gaseous fluid exceeding a threshold concentration. The threshold concentration is defined in accordance with a type of the particles of interest and a residence time of the sample. In particular, the apparatus is for radioactive anomaly detection of hidden or shielded special nuclear materials (SNM) or smuggled nuclear weapons in shipping containers at ports where the are loaded or unloaded via a crane system, or at check points when the containers are on trucks that move or pass through check points.
Abstract:
A device (10) operable in a ultra-high vacuum and in a cryogenic environment. The device has bi-stable solenoid motors (18) configured to drive a shutter assembly (12) defining an aperture (15) having a first shape when the motors are each disposed in the respective first position, and wherein the aperture has a second shape when the motors are each disposed in the respective second position. Actuators (30) responsive to the motors are thermally isolated from the cryogenic shutter assembly except when the motors position the shutter assembly to change a shape of the aperture. The device is suitable for use in FLIR and other thermally sensitive devices.
Abstract:
A drive mechanism (16A, 16B) having a bi-stable motor (18) driving an actuator (22) with a high starting torque, and a slower, regulated velocity as the actuator moves through its range of travel. This advantageously maintains high torque margins at low velocity, and lowers the kinetic energy of the bi-stable actuator at end of travel by limiting the terminal velocity (Wm) and establishing a softer stop. A solenoid may be used in one embodiment. Actual bi-stable motor values are obtained immediately before the move to maintain accurate control of the motor, such as the resistance and inductance of the motor coil. For instance, the bi-stable motor (46) may be driven into a stop (50, 52), and the coil resistance(Rm) may be calculated by sensing current (Im) associated with the calibration voltage (Vd). Inductance (Lm) may be measured similarly by applying low level AC currents. Back-emf is sensed through the coil resistance, and an estimated motor rotation rate is sent to a feedback loop (68) to maintain the desired rate.
Abstract:
A drive mechanism (16A, 16B) configured to drive a thermally isolated actuator (30) between two positions. The drive mechanism includes a rotary actuated motor (18) configured to rotatably drive a motor member (20), and a drive member (22) coupled to the motor member and having a drive arm (24, 42) configured to responsively move from a first position to a second position upon rotation of the motor member. An actuator (30) is responsive to movement of the drive arm (24) moved from the first position to the second position. A drive circuit (60) is configured to generate a pulse width modulated (PWM) drive signal (70) configured to controllably drive the motor, the PWM drive signal having a first duty cycle (Phase 1) configured to advance the drive arm from the first position, and having a second duty cycle (Phase 2) different than the first duty cycle as the drive arm approaches the second position. The drive signal may be removed (Phase3) before the drive arm (42) engages a hard stop (54). The drive mechanism may comprise at least one sensor (40) configured to determine a position of the drive arm (42) proximate the first position and proximate the second position. The actuator is thermally isolated from the drive arm (42) in both the first position and the second position.
Abstract:
A drive mechanism (16A, 16B) configured to drive a thermally isolated actuator (30) between two positions. The drive mechanism includes a rotary actuated motor (18) configured to rotatably drive a motor member (20), and a drive member (22) coupled to the motor member and having a drive arm (24, 42) configured to responsively move from a first position to a second position upon rotation of the motor member. An actuator (30) is responsive to movement of the drive arm (24) moved from the first position to the second position. A drive circuit (60) is configured to generate a pulse width modulated (PWM) drive signal (70) configured to controllably drive the motor, the PWM drive signal having a first duty cycle (Phase 1) configured to advance the drive arm from the first position, and having a second duty cycle (Phase 2) different than the first duty cycle as the drive arm approaches the second position. The drive signal may be removed (Phase3) before the drive arm (42) engages a hard stop (54). The drive mechanism may comprise at least one sensor (40) configured to determine a position of the drive arm (42) proximate the first position and proximate the second position. The actuator is thermally isolated from the drive arm (42) in both the first position and the second position.
Abstract:
A detector apparatus is provided and includes a collector having access to a sample of a gaseous fluid and a tester coupled to and disposed remotely from the collector. The tester includes a test chamber into which a sample is directed from the collector, an excitation element to excite the sample in the test chamber and a spectrum analyzing device coupled to the test chamber to analyze the excited sample for evidence of a concentration of particles of interest in the gaseous fluid exceeding a threshold concentration. The threshold concentration is defined in accordance with a type of the particles of interest and a residence time of the sample.
Abstract:
A device (10) operable in a ultra-high vacuum and in a cryogenic environment. The device has bi-stable solenoid motors (18) configured to drive a shutter assembly (12) defining an aperture (15) having a first shape when the motors are each disposed in the respective first position, and wherein the aperture has a second shape when the motors are each disposed in the respective second position. Actuators (30) responsive to the motors are thermally isolated from the cryogenic shutter assembly except when the motors position the shutter assembly to change a shape of the aperture. The device is suitable for use in FLIR and other thermally sensitive devices.