Locking pin can be withdrawn only when stress on the joint is negligible. Pin consists of a forward-pointing sleeve, a spring-loaded sliding handle, and a sliding plunger. Plunger movement controls installation and withdrawal of pin

Nelson, E. P.

Othman, T. E.

Zmuda, L. J.

English

NASA Technical Reports Server

September 1970	 Brief 70-10409 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage cornnierIa! 
application. Tech Briefs are available on a subscription basis from the Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Foolproof Quick-Release Locking Pin 
A novel quick-release locking pin has been devel-
oped which can be withdrawn (to separate linked 
members) only when stress on the joint is negligible. 
Handle	 First Member 
Plunger 
Detent Ball 
Push 'U Plunger	 Second Member 
Button	 Spring
Pin Installed and Locked 
The pin consists of a forward-pointing sleeve, with 
a spring-loaded sliding handle at its rear end, housing 
a sliding plunger that is urged backward (to its locking 
position) by a spring within the handle (see fig.). To 
a limited extent the plunger can slide forward against 
the plunger spring; the handle, backward against the 
handle spring. A groove near the front end of the 
plunger accommodates detent balls when the plunger 
is pushed forward by compression of its spring; when 
the plunger is released backward, the balls are forced 
outward into holes in the sleeve and so prevent with-
drawal of the pin. 
To install the pin, the plunger is pressed forward 
so that the balls fall into its groove; the pin is pressed 
into place, the plunger is released, and the balls lock 
the sleeve against withdrawal. 
To withdraw the pin, the plunger is pressed for-
ward to accommodate the locking balls and at the
same time pulls backward on the handle. If lateral 
stress on the pin is negligible the pin is withdrawn from 
the joint; if the stress is considerable, the handle 
spring is compressed and the plunger is forced back-
ward by the handle so that the balls are returned to 
their locking position. 
The allowable amount of stress on the joint at part-
ing is adjusted by adjustment of the pressure required 
for compression of the handle spring. If the stresses 
on the joint are too great for the pin to be withdrawn 
in the normal manner, hammering the forward end of 
the plunger simply ensures that the plunger is in its 
rearward position, with the locking balls preventing 
withdrawal of the pin. A forged stop on the forward 
end of the plunger prevents the plunger from being 
driven backward. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: TSP70- 10409 
Patent status: 
This invention is owned by NASA, and a patent 
application has been filed. Royalty-free, nonexclusive 
licenses for its commercial use will be granted by

NASA. Inquiries concerning license rights should be

made to NASA, Code GP, Washington, D.C. 20546. 
Source: T. E. Othman, E. P. Nelson
and L. J. Zmuda of

North American Rockwell Corp.

under contract to 
Marshall Space Flight Center
(MFS-18495) 
Category 07 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19700000395 2020-03-17T00:47:16+00:00Z


Foolproof quick-release locking pin

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