Viscous-film damper eliminates response lag of resonance generated noise when inserted into the thrust measuring system. This technique can be applied to automated devices when pulsed force or low order impact is involved, and where signal noise is produced by stopping or reversal of mechanical travel or by water hammer

Postma, R. W.

English

NASA Technical Reports Server

Tension 
Rod
Sensor 
November 1966	 Brief 66-10550 
NASA TECH BRIEF	 /M 
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. 
Damper Reduces Effects of Resonance on Force Transducer 
The problem: 
Resonance generated noise tends to interfere with a 
transducer signal when critical measurements of small 
thrust components are being made. Straight mechan-
ical damping has proven unsatisfactory due to re-
sponse lag that degrades the signal. 
The solution: 
A viscous-film damper that eliminates response 
lag is inserted into the thrust measuring system. 
How it's done: 
The damper assembly consists of a piston, axially 
restrained by a tension rod that is opposedly held by 
a disk spring and close fit in a fixed cylinder. A thin
layer of high viscosity fluid between the annular sur-
faces of piston and cylinder produces a laminar damp-
ing force. 
Notes: 
1. This technique can be applied to automated devices 
where pulsed force or low order impact is involved, 
as in production machines, dispenser, etc., where 
signal noise is produced by stopping or reversal of 
mechanical travel or by water hammer. 
2. The damper may be installed either in series with or 
parallel to the thrust transducer. Series installa-
tion is required in a system including acceleration 
compensation.
(continucd 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=19660000548 2020-03-11T17:44:44+00:00Z
3. Piston travel is limited by spring tension to the 	 Patent status: 
microinch level.	 No patent action is contemplated by NASA. 
4. Inquiries concerning this innovation may be di- 	 Source: R. W. Postma 
rected to:	 of North American Aviation, Inc. 
Technology Utilization Officer	 under contract to 
Western Support Office 	 Western Support Office 
150 Pico Boulevard 	 (WSO-321)
Santa Monica, California 90406 
Reference: B66-10550 
Brief 66-10550	 Category 05


Damper reduces effects of resonance on force transducer

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