Mechanical & Fluid Systems

Two SMA-Actuated Miniature Mechanisms

These mechanisms represent two different approaches to latch/release operation. The figures depict two miniature mechanisms actuated by strips made of shape-memory alloy (SMA). A typical SMA is a nickel-titanium alloy known by the trade name “Flexinol” or “Nitinol.” In preparation for a typical application, a suitably sized and shaped piece of an SMA is deformed by a predetermined amount at the lower of two operating temperatures, then mounted in a mechanism. When stroking of the mechanism in one direction is desired, the piece of SMA is heated above a transition temperature to make it return to the “remembered” undeformed state. When stroking of the mechanism in the opposite direction is desired, the SMA is cooled below the transition temperature to make it return to the deformed state.

Posted in: Briefs, Mechanical Components, Mechanics

Read More >>

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: Briefs, TSP, Mechanical Components, Mechanics

Read More >>

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: Briefs, TSP, Mechanical Components, Mechanics

Read More >>

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: Briefs, Mechanical Components, Mechanics

Read More >>

Nanoactuators Based on Electrostatic Forces on Dielectrics

Large force-to-mass ratios could be achieved at the nanoscale. Nanoactuators of a proposed type would exploit the forces exerted by electric fields on dielectric materials. As used here, “nanoactuators” includes motors, manipulators, and other active mechanisms that have dimensions of the order of nanometers and/or are designed to manipulate objects that have dimensions of the order of nanometers.

Posted in: Briefs, TSP, Mechanical Components, Mechanics

Read More >>

Two-Step Laser Ranging for Precise Tracking of a Spacecraft

A document proposes a two-step laser ranging technique for precise tracking of a coasting interplanetary spacecraft to determine the degree to which leakage of fuel, solar wind, and/or solar-radiation pressure causes it to deviate from a purely gravitational trajectory.

Posted in: Briefs, TSP, Mechanical Components, Mechanics

Read More >>

Synthetic Bursae for Robots

Functions would be similar to those of natural bursae. Synthetic bursae are under development for incorporation into robot joints that are actuated by motor-driven cables in a manner similar to that of arthropod joints actuated by muscle-driven tendons. Like natural bursae, the synthetic bursae would serve as cushions and friction reducers.

Posted in: Briefs, Mechanical Components, Mechanics

Read More >>

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.