Disconnect device is described, which consists of stud with enlarged end held in collet locked by pins, which are held in place by piston. When squib is fired, trapped combustion products force piston to release pins

Alexander, P., Jr.

Mcdougal, A. R.

English

NASA Technical Reports Server

ctor 
ring 
Stud 
December 1972
	 B72-10713 
NASA TECH BRIEF 
NASA Pasadena Office
	 -4r 
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. 
Squib-Operated Disconnect 
The problem: 
A small squib-operated disconnect was required 
for the Mariner Mars 1971 spacecraft; the device had 
to withstand repeated proof-testing at extreme vibra-
tion with no degradation of performance even when 
stressed at 1,360 to 2,160 kg (3000 to 5000 pounds) ten-
sion. Moreover, at the time of disconnection, neither 
gases nor debris could be ejected. 
The solution: 
A stud with an enlarged end is held in a collet 
locked by pins held in place by a piston; when a squib 
is fired, trapped combustion products force the piston 
to release the pins. 
How it's done: 
A multiple-jaw split-collet assembly is mounted in 
a cylindrical cavity as shown in the following diagram; 
the lower stud fastened to the collet serves as the 
means for attaching the disconnect to the rocket. 
When the upper stud (fastened to the spacecraft) is 
inserted into the collet, it will be held lightly by the 
natural spring action of the collet jaws; however, 
when the pin locator bushing is put in place, retaining 
pins are forced by the piston against the collet jaws. 
Since the pins prevent the collet jaws from expanding, 
the upper stud is held securely in place; the piston 
is held in position by the piston spring shown in the 
diagram. 
The annular volume E, formed by the clearance 
between the cap and the piston, is made gas-tight by 
0-rings. When the squib is fired, gases enter the squib 
port and the annular volume, forcing the piston to 
compress its spring; this action frees the retaining
Squib 
Port 
Pisto 
Pistol 
Sprin 
CoMe 
pins and allows the ejector spring to push the upper 
stud out of the collet jaws, as indicated in the follow-
ing diagram.
(continued overleaf) 
This documentwas 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=19720000712 2020-03-17T03:43:06+00:00Z
Exhaust gases from the squib are confined by 0-
rings to remain in the annular volume E; the retain-
ing pins have shoulders to prevent their being thrown 
out when the upper stud is released. The upper and 
lower studs are equipped with 0-rings to effect an 
hermetic seal of the inner working parts of the device.
Note: 
Requests for further iniormation may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office.. 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP 72-10713 
Patent status: 
This invention is owned by NASA, and a patent 
application has been filed: Inquiries concerning non-
exclusive or exclusive license for its commercial de-
velopment should be addressed to: 
NASA Patent Counsel 
Mail Code 1 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Source Paul Alexander, Jr. and 
Allan R. McDougal of
Caltech/JPL
under contract to
NASA Pasadena Office 
(NPO-11330) 
B72-10713	 Category 06


Squib-operated disconnect

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server