Fastener /Boydbolt/ has recently been designed to furnish positive lock and release characteristics that positively prevent accidental adverse functions of lock or release

Brueger, J.

Fenske, T.

Hamill, W.

Katz, M.

English

NASA Technical Reports Server

lat 
BOYDBOLT Spring Locking Balls 
November 1968
	
Brief 68-10512 
NASA TECH BRIEF 
NASA Teèh 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. 
Boydbolt, a Positive-Latch, Simple-Release Fastener 
Locking Spline	 Spindle 
Release Si 
-,*A, ) 1 
10
Soc 
RECEPTACLE
In the attachment of experimental equipment to 
support brackets within and without a space vehicle, a 
fastener is required that will remain in the latched po-
sition under high dynamic preload but permit removal 
simply and by the application of small force. 
A fastener (Boydbolt) has recently been designed to 
furnish these features plus positive lock and release 
characteristics that positively prevent accidental ad-
verse functions of lock or release. 
A floating receptacle, specially designed to receive 
the Boydbolt, is riveted or screwed to the support 
structure. This receptacle contains two locking and 
two release splines in its outer section. Inside, the re-
ceptacle is machined to form a four-lead thread that 
has opposing 90° segments removed to provide a 
breach-type engagement for the bolt. The forward 
portion of the bolt is threaded in a mating pattern, 
i.e., flats are machined on approximately 90° oppos-
ing segments so that the bolt may be freely inserted 
into the receptacle. Immediately above these threads 
are two locking balls whose action is controlled by 
the position of a central spindle. In the raised posi-
tion, the spindle will prevent the balls from moving 
towards the center of the bolt, thus providing for 
positive engagement of the balls with either the lock- 
ing or release splines. The spindle is maintained in
its free position by a spring. The top of the bolt is 
machined to a double hex socket to receive a lock or 
release hex-headed hand tool. 
To assemble the Boydbolt fastener, insertion of the 
hand tool in the bolt socket causes the spindle to be 
depressed, thus releasing the locking balls. The bolt 
assembly is then inserted into the receptacle with the 
locking balls oriented in line with the release spline. 
The bolt is now rotated clockwise until the balls en-
gage the locking spline and stop the bolt from turning 
further, the threads of bolt and receptacle now being 
fully engaged. Upon withdrawal of the hand tool from 
the bolt, the spindle moves in to force the balls into 
the locking splines, thus preventing any rotation of the 
bolt assembly under vibration conditions. 
Notes: 
Thisdevice lends itself to manufacture in a vari-
ety of sizes both as to length and diameter so that 
a wide range of applications may be accom-
modated. 
2. Documentation for the innovation is available from: 
Clearinghouse for Federal Scientific 
and Technical Information 
Springfield, Virginia 22151 
Price $3.00 
Reference: B68-10512	 (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=19680000468 2020-03-12T06:03:17+00:00Z
Patent status: 
Inquiries about obtaining rights for the commer-
cial use of -this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: W. Hamill, J. Brueger, 
• M. Katz, and T. Fenske
of The Bendix Corporation 
under contract to 
Manned Spacecraft Center 
(MSC-13061)
. 
Brief 68-10512	 •	 Category 05


Boydbolt, a positive-latch, simple-release fastener

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