Elasticity is determined by isolators physical dimensions and by type of elastomer used. Once elastomer is selected and cast between two concentric tubes of device, isolator elasticity will remain fixed. Isolators having same dimensions can be built to different elasticity requirements using same elastomer

Bright, C.

Owens, L.

English

NASA Technical Reports Server

July 1974	 B74-10039 
NASA TECH BRIEF 
John F Kennedy 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. 
Control of Elasticity in Cast Elastomeric Shock/Vibration Isolators 
The problem: 
Elasticity in cast elastomeric shock/vibration isolators 
(see Figure 1) is determined by their physical dimensions 
and by the type of elastomer used. Once the elastomer 
is selected and cast between the two concentric tubes of 
the device, the isolator elasticity will remain fixed. 
There is no effective way to produce isolators to 
different elasticity requirements without changing their 
dimensions or using different elastomers. 
Elastomer 
Figure 1. Standard Isolator Shock/Vibration 
The solution: 
Isolators having the same dimensions can be built to 
different elasticity requirements using the same elas-
tomer.
Figure 2. Improved Shock/Vibration Isolator 
The second method is very similar. Instead of wax, a 
cylindrical spacer of low-density foam such as poly-
urethane is inserted. When more elastomer is added to 
complete the mount, the foam then effectively acts as a 
void. Again the size of this spacer may be varied to meet 
different elasticity requirements. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
Reference: B74-10039 
lfITIl1'
Small-

Diameter
Hole 
Low-Temperatur 
Melting Point Solid 
Low-Density Foam 
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How it's done: 
Two approaches may be used. In the first, the elas-
tomer is poured between the two concentric tubes to 
height h 1 as shown in Figure 2. Next, a low-temperature 
melting point material such as wax is poured to height 
h2 . After the wax hardens, more elastomer is added. 
When the elastomer has set, two small-diameter holes 
are drilled in the isolator outer wall at the wax layer 
level. The wall then is heated and the molten wax is 
poured out, leaving a void. The size of this void may be 
varied, depending on the elasticity desired.
Patent status: 
Inquiries concerning rights for the commercial use of 
this invention should be addressed to: 
Patent Counsel 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
Source: L. Owens and C. Bright

Kennedy Space Center 
(KSC-10850) 
Category 07, 08 
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Control of elasticity in cast elastomeric shock/vibration isolators

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