Slide-wire system with a twist level slide device incorporates automatic descent and braking for the safe and rapid evacuation of personnel from tall structures. This device is used on any tall structure that might require emergency evacuation. It is also used to transfer materials and equipment

Billings, C. R.

Mc Daris, R. A.

Mc Gough, J. T.

Neal, P. F.

English

NASA Technical Reports Server

Vertical Adjustment Bolts
SLOPE OF CABLE 
DURING DESCENT 
SLOPE OF CABLE 
AFTER DESCENT 
Slide Win
olt 
December 1966
	 Brief 66-10575 
S	 NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Emergency Escape System Uses Self-Braking Mechanism on Fixed Cable 
The problem: 
To design an emergency escape system that incorpo-
rates automatic descent and braking for the safe and 
rapid evacuation of personnel from tall structures. 
Other escape systems use handbrakes to control 
descent and braking. Manual operation causes injuries 
to users because of stopping too soon and piling up 
other evacuees or not stopping soon enough and 
hitting the ground terminal.
The solution: 
A slide-wire system with a twist level slide device, 
which is a self-braking mechanism. 
How it's done: 
Each twist level slide device is attached to a slide 
wire or fixed cable suspended between the tall struc-
ture and an A-frame terminal. Prior to use, the device 
is retained at the structure with breakaway string. 
(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.
https://ntrs.nasa.gov/search.jsp?R=19660000573 2020-03-11T17:45:42+00:00Z
The twist lever slide device is attached to the slide-
wire cable as shown. Before descent, the cable contacts 
only the support bolt. Clearance between the cable 
and pressure bolt is set with the vertical adjustment 
bolts. As the device descends, its angle of suspension 
remains essentially constant because of the attached 
load. The slide wire cable has a decreasing angle of 
slope, and as the slope decreases, the cable eventually 
contacts the pressure bolt. The resultant twisting of 
the cable forces the device to a smooth, but rapid, 
stop. 
The initial clearance setting between the cable and 
the pressure bolt determines the eventual stopping 
point of the twist lever slide device. Field experi-
mentation will quickly determine proper adjustment 
bolt settings for stopping at a predetermined point. 
To evacuate the structure, each person hooks a 
personal sling-type harness to one of the twist lever 
slide devices. The person's weight breaks the string 
retaining the device, and it descends along the slide 
wire. The device automatically stops at ground level 
before reaching the A-frame terminal.
Notes: 
I. This system is presently in operation at John F. 
Kennedy Space Center. 
2. The automatic descent and braking features permit 
evacuation of unconscious or injured personnel. 
3. This device could be used on any tall structure 
that might require emergency evacuation. It could 
also be used to transfer materials and equipment. 
4. Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Kennedy Space Center 
Kennedy Space Center, Florida 32899 
Reference: B66-10575 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: C. R. Billings, R. A. McDaris,

J. T. McGough, and P. F. Neal

(KSC-66-44) 
j	 TLLI
• 
CV 
Brief 66-10575	 Category 05


Emergency escape system uses self-braking mechanism on fixed cable

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