Device includes cable wound on reel; special assembly enclosed in fluid medium controls unwinding speed of cable during descent. Device is compact and reliable. It can be rewound quickly because reel disengages from latches when it is turned in opposite direction

Belew, R. R.

English

NASA Technical Reports Server

Latch
Key 
Latch 
A—A	 B—B 
0 1 
Inch\ 
01
cm 
November 1974	 B74-10226 
NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Emergency Descent Device 
A new device has been developed for emergency 
descents from tall structures. The device includes a 
cable wound on a reel. A special assembly enclosed in a 
fluid medium controls the unwinding speed of the 
cable during a descent. 
The basic mechanism as illustrated includes a cable 
reel, a latch ring, and a vane-rotor assembly enclosed in 
a fluid. When the cable is unwinding, the spinning reel 
engages two spring-loaded latches. The resulting torque 
is transmitted to the latch ring which is keyed to 
rotate the vane-rotor assembly.
While the vane-rotor assembly is spinning, the vane 
slides back and forth in the plane perpendicular to the 
rotor axis. This vane includes a number of bypass 
orifices (not shown). Fluid moving through these orifices 
controls the torque of the spinning rotor which, in 
turn, allows the reel to unwind at safe speeds. 
The device is compact and reliable. It can be re-
wound very quickly because the reel disengages from 
the latches when it is turned in the opposite direction. 
Emergency Descent Device
(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights.
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https://ntrs.nasa.gov/search.jsp?R=19740000226 2020-03-17T13:55:08+00:00Z
Notes: 
1. Another emergency descent device is described in 
NASA Tech Brief 73-10369 (MFS-22720). 
2. Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code ATO1 
Marshall Space Flight Center, Alabama 35812 
Reference: B74-10226
Patent status: 
Inquiries concerning rights for the commercial use of 
this invention should be addressed to: 
Patent Counsel 
Marshall Space Flight Center 
Code CCO1 
Marshall Space Flight Center, Alabama 35812 
Source: R. R. Belew
Marshall Space Flight Center
(MFS-23074)
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. 
B74-10226
	 Category 05, 07


Emergency descent device

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