Wire Wound Springs versus Machined Springs; A Comparison

This white paper addresses the high points of choosing between Machined Springs and Wire Wound Springs, and goes into further detail regarding the unique differences that can significantly affect design considerations. Complete with charts detailing technical benefits between the two methods of producing springs. This educational white paper is an essential reference document for any engineer working with mechanical components.

Posted in: White Papers, Mechanical Components

Lightweight, Reusable Payload Launch and Transportation Latch

This device can be used for latching cargo in aircraft, supporting hazardous materials, or latching pallets and shipping boxes.

This innovation addresses the problem of automatic engagement and disengagement of payloads from their transport vehicle when lifted by a crane or other material handling device. The prior state-of-the-art is in material handling devices that require personnel to activate the latch, or latches that are actuated by heavy, bulky actuator systems fixed to the transportation device. These require significant accommodations on the transport vehicle to mate to the latch.

Posted in: Briefs, Mechanical Components, Mechanics, Materials handling, Construction vehicles and equipment, Industrial vehicles and equipment

Structural Assembly Incorporating Integral Thermal Heat Spreader for Cold Plate Cooling

Lyndon B. Johnson Space Center, Houston, Texas

In a structural cold plate, typically there is a structural member such as a honeycomb panel or a brazed sandwich assembly that provides the structural strength, and at least one cold plate that cools equipment attached to the structural member. The cold plate is typically located between the structural member and the item it is cooling. With this configuration, the cold plate’s location, shape, and size are limited to being placed beneath the item it is cooling. This requires an additional envelope that is equal to the cold plate thickness. Being able to locate the cold plate in locations other than beneath the item it is cooling would have multiple benefits including reduced envelope requirements in the direction of the item it is cooling, as well as allowing a larger cold plate cooling footprint.

Posted in: Briefs, Mechanical Components, Cooling, Parts

Advanced Magnetostrictive Regulator, Valve, and Force-to-Angle Sensor

The components are lightweight, compact, highly precise, and can operate over a wide range of temperatures and pressures.

Typical aerospace rocket engines use valves to control the flow and pressures of propellant and pressurants. These typical valves are designed to operate with a mechanical, electromechanical, or pneumatic operator. They all have at least one, and often multiple, penetrations from the fluid to the operator’s prime mover. The penetrations are sources for leaks, failures, and are often considered to be unreliable for use in single string systems. Therefore, the fluid system designer frequently will utilize several parallel path valves, effectively doubling the resources needed to accomplish the task. These redundant valves allow for isolation of the potentially leaking fluid penetrations. If the systems cannot afford the multiple path approach, then the valves are subjected to high levels of testing and quality control, or utilize bellows or other expensive and difficult to handle/design and costly features.

Posted in: Briefs, Mechanical Components, Mechanics, Computational fluid dynamics, Sensors and actuators, Rocket engines, Transmission valves

Circular Cross-Section Blades for a Sampling Device

The blades can be used for shallow or deep sampling, low-strength or high-strength sampled media, and consolidated or unconsolidated sampled material.

To date, there are solutions that can collect samples by being deployed from a distance from a low-gravity body or using a touch-and-go approach. To increase precision collection of samples from both consolidated and unconsolidated material, allow for precise sampling location selection, and impart a low impact on the spacecraft, bi-blade sampling devices have been developed.

Posted in: Briefs, Mechanical Components, Mechanics, Materials handling, Spacecraft

Clamshell Sampler

One action with one actuator is used to acquire and retain the sample.

NASA’s Jet Propulsion Laboratory, Pasadena, California

The Clamshell mechanism, with one quick action, acquires and retains a sample from a small body surface while minimizing sampling energy. The sampler has two quarter-sphere buckets that are driven into the small body surface. One mechanism drives a linkage that causes the two buckets to rotate about a common axis to close the buckets into each other. A benefit of this design is that one action with one actuator is used to acquire and retain the sample. Thin blades result in minimum sampling energy.

Posted in: Briefs, Mechanical Components, Sensors and actuators, Energy conservation, Test equipment and instrumentation, Spacecraft

Shape Memory Alloy Rock Splitter

This splitter can be applied wherever explosive or impact techniques cannot be used.

John H. Glenn Research Center, Cleveland, Ohio

A working prototype of a non-explosive, static rock splitter for space exploration using shape memory alloys (SMAs) as the driving member also has terrestrial applications. The static, compact, non-explosive shape memory alloy rock splitter (SMARS) was designed for sampling geological deposits, including planetary bodies such as the Moon, Mars, and near-Earth asteroids (Figure 1). The splitter employs high-temperature SMAs that generate extremely large forces in response to thermal loads, while providing a compact and cost-effective method for fracturing rocklike materials and minerals when compared to hydraulic or explosive-based alternatives. The active elements, in the form of pre-shaped cylindrical pellets, are used in conjunction with custom-built DC voltage heaters placed in boreholes.

Posted in: Briefs, Mechanical Components, Test equipment and instrumentation, Mining vehicles and equipment, Spacecraft

Passive, Low-Insertion-Force/High-Retention-Force Cam Plug Design for Sample Tube Sample Caging

This plug could be used for soil and sediment samples in petroleum and mining industries, or to plug products of various sizes tightly in tubes for shipping.

NASA’s Jet Propulsion Laboratory, Pasadena, California

AMars “sample caching rover” mission designed to collect, document, and package samples for future collection and return to Earth was recommended as the highest-priority mission for 2013–2022 by the 2011 Planetary Decadal Survey. A key premise of the Mars 2020 rover, which will gather samples for potential future return, is that it should be possible for the samples to be packaged and left on Mars for an extended period of time (at least five Mars years) without loss of scientific value. Two particularly important characteristics of a sample are the structure and relative positioning of the rock fragments and grains. These characteristics can be affected by shock and vibration that could fracture the sample and create relative movement among the fragments and grains, and therefore cause loss of valuable scientific information.

Posted in: Briefs, Mechanical Components, Packaging, Vibration, Test equipment and instrumentation, Spacecraft

Design Support and Analysis Tool for Pyrotechnically Actuated Valves

Lyndon B. Johnson Space Center, Houston, Texas

This software predicts flow through the initiator of a Primer Chamber Assembly Valve. These valves exhibited a potential failure mode for specific operating conditions where dual simultaneous firings of the initiator occurred. The software tool was able to identify a fluid dynamic source for this potential failure mode. Furthermore, the software was also used to provide new conceptual designs that may alleviate or eliminate these failure modes.

Posted in: Briefs, Mechanical Components, Computational fluid dynamics, Failure modes and effects analysis, Sensors and actuators, Valves

Deployable Extra-Vehicular Activity Platform (DEVAP) for Planetary Surfaces

Potential applications include stable work ramps for vehicles, vessels, or portable shelters.

The Deployable Extra-Vehicular Activity Platform (DEVAP) is a staging platform for egress and ingress attached to a lunar, Mars, or planetary surface habitat airlock, suitlock, or port. The DEVAP folds up into a compact package for transport, and deploys manually from its attached location to provide a ramp and staging platform for extravehicular activities (see figure).

Posted in: Briefs, Mechanical Components, Mechanics, Spacecraft

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