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Pneumatically Actuated Miniature Peristaltic Vacuum Pumps

Small, rugged, low-power pumps could be fabricated inexpensively. Pneumatically actuated miniature peristaltic vacuum pumps have been proposed for incorporation into advanced miniature versions of scientific instruments that depend on vacuum for proper operation. These pumps are expected to be capable of reaching vacuum-side pressures in the torr to millitorr range (from ≈133 down to ≈0.13 Pa). Vacuum pumps that operate in this range are often denoted roughing pumps. In comparison with previously available roughing pumps, these pumps are expected to be an order of magnitude less massive and less power-hungry. In addition, they would be extremely robust, and would operate with little or no maintenance and without need for oil or other lubricants. Portable mass spectrometers are typical examples of instruments that could incorporate the proposed pumps. In addition, the proposed pumps could be used as roughing pumps in general laboratory applications in which low pumping rates could be tolerated.

Posted in: Mechanical Components, Briefs, TSP

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Miniature Gas-Turbine Power Generator

Energy density would greatly exceed that of a typical battery system. A proposed microelectromechanical system (MEMS) containing a closed- Brayton-cycle turbine would serve as a prototype of electric- power generators for special applications in which high energy densities are required and in which, heretofore, batteries have been used. The system would have a volume of about 6 cm3 and would operate with a thermal efficiency >30 percent, generating up to 50 W of electrical power. The energy density of the proposed system would be about 10 times that of the best battery-based systems now available, and, as such, would be comparable to that of a fuel cell.

Posted in: Mechanical Components, Briefs, TSP

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Improved Gear Shapes for Face Worm Gear Drives

These shapes offer potential for increasing precision and reducing vibration and noise. Shapes different from the traditional ones have been proposed for face worm gears and for conical and cylindrical worms that mesh with them. The proposed shapes are based on the concept of generating a face worm gear surface by use of a tilted head cutter instead of by the traditional use of a hob. (As used here, “head cutter” is also meant to signify, alternatively, a head grinding tool.)The gear-surface-generation equipment would be similar to that used for generation of spiral bevel and hypoid gears. In comparison with the corresponding traditional hob, a tilted head cutter according to the proposal would be larger, could be fabricated with greater precision, and would enable the generation of gear surfaces with greater precision and greater productivity.

Posted in: Mechanical Components, Briefs, TSP

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Alternative Way of Shifting Mass To Move a Spherical Robot

A payload would change its position by lengthening and shortening suspension cables. An alternative method of controlled shifting of the center of mass has been proposed as a means of locomotion of a robot that comprises mostly a payload inside a hollow, approximately spherical shell. The method would be applicable to robots that include rigid, semirigid, or flexible inflated shells, including those of the “beach-ball rover” type, variants of which have been described in several previous NASA Tech Briefs articles.

Posted in: Mechanical Components, Briefs, TSP

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Fastener Starter

This tool is superior to prior screw and nut starters. The Fastener Starter is a creative solution to prevent the loss of small fasteners during their installation. This is the only currently available tool that can firmly grip and hold a single screw, bolt, nut, washer, spacer, or any combination of these parts. Other commercially available fastener starters are unable to accommodate a variety of parts simultaneously. The Fastener Starter is a more capable and easier tool to use than prior tools. Its compact size allows it to be used effectively in cramped, difficult-to-see locations. Its design also allows it to be used with or without handles and extenders in other difficult-to-reach locations. It provides better protection against cross threading and loss of fasteners and associated parts. The Fastener Starter is non-magnetic and does not off-gas, thus meeting flight hardware requirements.

Posted in: Mechanical Components, Briefs

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Temperature-Controlled Clamping and Releasing Mechanism

A report describes the development of a mechanism that automatically clamps upon warming and releases upon cooling between temperature limits of 180 K and 293 K.

Posted in: Mechanical Components, Briefs, TSP

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Piezo-Operated Shutter Mechanism Moves 1.5 cm

This shutter is designed for use as part of an atomic clock. The figure shows parts of a shutter mechanism designed to satisfy a number of requirements specific to its original intended application as a component of an atomic clock to be flown in outer space. The mechanism may also be suitable for use in laboratory and industrial vacuum systems on Earth for which there are similar requirements. The requirements include the following:

Posted in: Mechanical Components, Briefs, TSP

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