Technique incorporates weld-free method for securing flanges to projecting ends of unmachined box-beam framework so flanged structure may be reused without modification. One such framework may be readily assembled to another by simply matching flanges together and passing connecting members between preformed holes in structures

Gilman, M. M.

English

NASA Technical Reports Server

f	 Jaiiary 1975	 B74-10273 
NASA TECH BRIEF 
Lyndon B. Johnson Space Center 
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. 
Flange Design for Large-Scale Modular Assembly Jigs 
The problem: 
In previous large-scale modular assembly jigs, the 
mounting and interconnecting flanges have been 
attached by welding. Such all-welded structures have 
the usual disadvantages associated with welding, e.g., 
the lack of accurate dimensioning, coplanarity, and 
parallelism. Thus during the assembly of such 
modules special alinement of the flanged joints is 
necessary.
The solution: 
A new technique incorporates a weld-free method 
for securing flanges to the projecting ends of an un-
machined box-beam framework in such a way that the 
flanged structure may be reused without modifi-
cation. One such framework may be readily 
assembled to another by simply matching the flanges 
together and passing connecting members between 
preformed holes in the structures. 
(B) 
Drill Bit	 Locating Pad on 
 
End 
End  
Special Drill 
Bushing
Modular Assembly Jig 
Locating Pad
(C) 
Installation and Alinement 
of Locating Pad and Collar 
Weld-Free Installation of Load-Bearing Flanges
(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=19740000273 2020-03-17T13:57:12+00:00Z
How it' done: 
The technique consists of aiming and doweling sets 
of precision-machined locating pads and collars to the 
unmachined square box-beam ends of the modular 
assembly jig to provide distortion-free load-bearing 
flanges (see figure). The floating pad-and-collar 
design permits the lateral alinement of the pad centers 
relative to master grid-plate centers. At the pad 
centers are tooling holes 3/4 in. (1.9 cm) in diameter. 
These holes are alined on 70.00-in. (177.80-cm) grid 
centers, which are accurately located with respect to 
each other within ±0.005 in. (±0.013 cm). 
The collar is connected to the pad by a set of 
machine screws, passing through slightly oversize 
holes in the collar and into tapped holes in the pad, 
and by a pair of dowel pins driven through registering 
holes in both members. The attachment collars then 
permit movement for exact length and perpendicu-
larity alinement, prior to being attached by dowels to 
the box-beam ends. By this means, the combined 
planar deviation relative to the master tooling 
grid-plate can be held to ±0.015 in. (±0.038 cm). 
Because the tooling is held to close tolerance while 
being fabricated, special alinement during the 
buildup of several modules is not necessary.
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Johnson Space Center 
Code AT3 
Houston, Texas 77058 
Reference: TSP74-10273 
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 
development should be addressed to: 
Patent Counsel 
Johnson Space Center 
Code AM 
Houston, Texas 77058 
Source: M. M. Gilman of

Rockwell International Corp.

under contract to

Johnson Space Center 
(MSC-1.9372) 
Categories: 06 (Mechanics) 
07 (Machinery)	 0 
08 (Fabrication Technology) B74-10273


Flange design for large-scale modular assembly jigs

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