The purpose of this study was to (1) evaluate the mechanical efficiency (ME) of two commercially available lever-propulsion mechanisms for wheelchairs and (2) compare the ME of lever propulsion with hand rim propulsion within the same wheelchair. Of the two mechanisms, one contained a torsion spring while the other used a roller clutch design. We hypothesized that the torsion spring mechanism w...

1 , A. Stroupe 2 , H. Aghazarian 3 , M. Garrett 4 , P. Younse 5 , and M. Powell 6 . 1 Jet Propulsion Laboratory, MS 198-219, 4800 Oak Grove Drive, Pasadena, CA 91109, [email protected]; 2 Jet Propulsion Laboratory, MS 198-219, 4800 Oak Grove Drive, Pasadena, CA 91109, [email protected]; 3 Jet Propulsion Laboratory, MS 198219, 4800 Oak Grove Drive, Pasadena, CA 91109, Hran...

Over the last 10 years the electrical propulsion fleet grew three times faster than the world fleet. This paper provides an overlook of the main drivers supporting this impressive growth and explores supporting drivers for future growth. The paper also explores two emerging technologies in electrical propulsion and distribution and how these influence ship design: DC distribution and energy sto...

The nuclear thermal rocket (NTR) is a proven, high thrust propulsion technology that has twice the specific impulse (Isp ~900 s) of today’s best chemical rockets. During the Rover and NERVA (Nuclear Engine for Rocket Vehicle Applications) programs, twenty rocket reactors were designed, built and ground tested. These tests demonstrated: (1) a wide range of thrust; (2) high temperature carbide-ba...

Studies of manual wheelchair propulsion often assume bilateral symmetry to simplify data collection, processing, and analysis. However, the validity of this assumption is unclear. Most investigations of wheelchair propulsion symmetry have been limited by a relatively small sample size and a focus on a single propulsion condition (e.g., level propulsion at self-selected speed). The purpose of th...

Objective. To compare the energy expenditure of two types of manual wheelchair propulsion. Design. Experimental and comparative design using matched controls. Background. A new manual wheelchair propulsion technique is proposed to minimize the overload exerted on the upper limb during the classical propulsion. The energy cost and other parameters of this new propulsion technique were evaluated....

During wheelchair propulsion, in order to apply power to the pushrim effectively, shoulder and trunk stabilization is needed to control arm movements and the consequent transfer of power from the limbs through to the pushrim. Available trunk control may be one of the most important force-generating mechanisms during wheelchair propulsion, particularly when an individual is fatigued or propellin...