Joints between two rigid materials lined with velcro fabric can now be broken with ease using any one of several methods. Three such methods are applicable to either hook or loop fabric

Whitacre, H. E.

English

NASA Technical Reports Server

Base Mated ExpandableTube 
FIGURE 3 
Pile 
FIGURE 4
October 1969
	 Brief 69-10388 
NASA TECH BRIEF 
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. 
Quick-Release Hook- and-Loop Fastener 
Collar
Reaction 
Layer 
1 
46 
Journal 
Shaft
____ Af 
Bearing Block
FIGURE 1 
Loop Fibers 
Collar 
Cam 
AW ^  
B se Material 
 Retraction Layer 
Aperture Journal Shaft Expandable	 Base 
FIGURE 2	
Tube	 Material 
Figs. 1 and 2. The cam method of separation. A loop-pile fabric adheres to a rigid base material. Groups 
of fibers protrude through apertures in a retraction layer; each aperture is ringed by a collar. The retraction 
mechanism consists of either strip cams rotatable about journal shafts mounted in bearing blocks, or ex-
pandable tubes. The cams are linked by cranks and thrust links, and rotated by a lever. When the lever lies 
parallel with the fabric, the cams lie flat, the plate is lowered, and the looped pile projects freely through 
the collars and engages applied hooks (fig. 2). When the lever is raised, the layer rises, the loops in the 
fibers are straightened by the collars, and the opposing hooks are released. A variation of this method uses 
expandable pneumatic tubes (fig. 2; right half) or perforated expandable mats instead of cams. Figs. 3 and 
4. For still another method the pile groups are confined in rows by channel elements (fig. 3). Under the 
channel elements are either cams or expandable tubes (fig. 4). When the channel elements are raised, the 
loops are straightened (fig. 4). The perpendicularly parallel displacement of the elements, relative to the 
rigid base material, may be ensured by provision of guide means (not illustrated). 
The problem:	 flexes as force is applied to the material's edge in 
Velcro fasteners incorporate two types of fabric: 	 order to break the joint progressively. If neither 
a "hook" fabric attached to one base material and a 	 material is flexible the joint can be broken only by 
"loop" fabric attached to the other. Normally one of 	 application of force that is excessive relative to the 
the two fabrics is applied to a flexible material that 	 joint's area—between 5 and 40 lb/inch 2 , depending 
(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=19690000383 2020-03-16T18:17:46+00:00Z
on the material in hooks and loops (stainless steel, 
nylon, and polyester have been used successfully). 
The solution: 
Joints between two rigid materials can now be 
broken with ease by use of any of various methods. 
Three such methods (figs. 1-4) are applicable to either 
the hook or the loop fabric. The essence of each 
method is that all the hooks or all the loops are 
straightened simultaneously; the need for "peeling" 
is eliminated. 
Many modifications of this idea are possible. The 
surfaces of the rigid materials need not be flat or 
parallel planar.
Note: 
Documentation is available from: 
Clearinghouse for Federal Scientific 
and Technical Information 
Springfield, Virginia 22151 
Price: $3.00 
Reference: TSP69- 10388 
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

madeto NASA, Code GP, Washington, D.C. 20546.

Source: Horce E. Whitacre

Manned Spacecraft Center 
(MSC-10950)
is 
Brief 69-10388	 Category 05


Quick-release hook-and-loop fastener

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