Mechanical Components

System Regulates the Water Contents of Fuel-Cell Streams

An assembly of devices provides for both humidification of the reactant gas streams of a fuel cell and removal of the product water (the water generated by operation of the fuel cell). The assembly includes externally-sensing forward-pressure regulators that supply reactant gases (fuel and oxygen) at variable pressures to ejector reactant pumps. The ejector supply pressures depend on the consumption flows. The ejectors develop differential pressures approximately proportional to the consumption flow rates at constant system pressure and with constant flow restriction between the mixer-outlet and suction ports of the ejectors. For removal of product water from the circulating oxygen stream, the assembly includes a water/gas separator that contains hydrophobic and hydrophilic membranes. The water separator imposes an approximately constant flow restriction, regardless of the quality of the two phase flow that enters it from the fuel cell. The gas leaving the water separator is nearly 100 percent humid. This gas is returned to the inlet of the fuel cell along with a quantity of dry incoming oxygen, via the oxygen ejector, thereby providing some humidification.

Posted in: Mechanical Components, Briefs

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Magnetically Attached Multifunction Maintenance Rover

This robot could move along a ferromagnetic structure in any orientation. A versatile mobile telerobot, denoted the magnetically attached multifunction maintenance rover (MAGMER), has been proposed for use in the inspection and maintenance of the surfaces of ships, tanks containing petrochemicals, and other large ferromagnetic structures. As its name suggests, this robot would utilize magnetic attraction to adhere to a structure. As it moved along the surface of the structure, the MAGMER would perform tasks that could include close-up visual inspection by use of video cameras, various sensors, and/or removal of paint by water-jet blasting, laser heating, or induction heating.

Posted in: Mechanical Components, Briefs, TSP

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Method of Calibration for a Large Cathetometer System

This method costs considerably less than does a prior method A method of calibration has been devised for a pair of mutually orthogonal two-axis cathetometers that, when used together, yield measurements of three-dimensional positions of objects mounted on an optical bench. Each cathetometer has a horizontal travel of 1.8 m and a vertical travel of 1.2 m. The cathetometers are required to measure X ,Y, and Z coordinates (see figure) to within ±0.005 in.(±0.127 mm).

Posted in: Mechanical Components, Briefs, TSP

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Advanced Infant Car Seat Would Increase Highway Safety

This system would keep a baby safe, comfortable, and entertained, thereby reducing distractions for an adult driver. An advanced infant car seat has been proposed to increase highway safety by reducing the incidence of crying, fussy behavior, and other child-related distractions that divert an adult driver's attention from driving. In addition to a conventional infant car seat with safety restraints, the proposed advanced infant car seat would include a number of components and subsystems that would function together as a comprehensive infant-care system that would keep its occupant safe, comfortable, and entertained, and would enable the driver to monitor the baby without having to either stop the car or turn around to face the infant during driving.

Posted in: Mechanical Components, Briefs

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Development of Biomorphic Flyers

Autonomous flight control and navigation in small size is offered for planetary and terrestrial exploration applications. Biomorphic flyers have recently been demonstrated that utilize the approach described earlier in "Bio-Inspired Engineering of Exploration Systems" (NPO-21142), NASA Tech Briefs ,Vol.27, No.5 (May 2003), page 54, to distill the principles found in successful, nature-tested mechanisms of flight control. Two types of flyers are being built, corresponding to the imaging and shepherding flyers for a biomorphic mission described earlier in "Cooperative Lander-Surface/Aerial Microflyer Missions for Mars Exploration" (NPO-30286), NASA Tech Briefs, Vol.28, No.5 (May 2004), page 36. The common features of these two types of flyers are that both are delta-wing airplanes incorporating bio-inspired capabilities of control, navigation, and visual search for exploration. The delta-wing design is robust to ~40 G axial load and offers ease of stowing and packaging.

Posted in: Mechanical Components, Briefs, TSP

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Second-Generation Six-Limbed Experimental Robot

This robot is designed to be more agile and dexterous than its predecessor. The figure shows the LEMUR II—the second generation of the Limbed Excursion Mechanical Utility Robot (LEMUR), which was described in "Six-Legged Ex- perimental Robot " (NPO-20897), NASA Tech Briefs,Vol.25, No.12 (December 2001), page 58. The LEMUR II incorporates a number of improvements, including new features, that extend its capabilities beyond those of its predecessor, which is now denoted the LEMUR I.

Posted in: Mechanical Components, Briefs, TSP

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Miniature Linear Actuator for Small Spacecraft

A report discusses the development of a kit of mechanisms intended for use aboard future spacecraft having masses between 10 and 100 kg. The report focuses mostly on two prototypes of one of the mechanisms: a miniature linear actuator based on a shape-memory-alloy (SMA) wire. In this actuator, as in SMA-wire actuators described previously in NASA Tech Briefs, a spring biases a moving part toward one limit of its stroke and is restrained or pulled toward the other limit of the stroke by an SMA wire, which assumes a slightly lesser or greater "remembered" length, depending on whether or not an electric current is applied to the wire to heat it above a transition temperature. Topics addressed in the report include the need to develop mechanisms like these, the general approach to be taken in designing SMA actuators, tests of the two prototypes of the miniature linear actuators,and improvements in the second prototype over the first prototype resulting in reduced mass and increased stroke. The report also presents recommendations for future development, briefly discusses problems of tolerances and working with small parts, states a need for better understanding of behaviors of SMAs, and presents conclusions.

Posted in: Mechanical Components, Briefs, TSP

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