Table floats in tank of water and has air compartments underneath. Table height and level are controlled by automatic adjustment or air pressure within these compartments

Burch, J. L.

English

NASA Technical Reports Server

.Solenoid
/ 
Chambers 
Rubber 
Band 
Air
Bearing
Pendulum 
September 1974	 B74-10144 
NASA TECH BRIEF 
Marshall Space Flight 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. 
Self-Leveling Load Table 
The problem: 
Docking maneuvers between space vehicles are simu-
lated on specially designed tables which must remain 
horizontal at all times. The mechanical tables that are 
used for this purpose are very heavy and bulky. They 
rest on many legs which need frequent adjustments 
because the changing temperatures of the surrounding 
environment offset leveling. In addition, the tables are 
sensitive to underground shocks and therefore require 
expensive substructural supports.
The solution: 
A new table has been developed which levels itself 
automatically. 
How it's done: 
The table floats in a tank of water and has air 
compartments underneath. Table height and level are 
controlled by the automatic adjustment of air pressure 
within these compartments. 
Solenoids 
Rubber 
Band
Solenoid 
Self-Leveling Table Assembly
(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=19740000144 2020-03-17T14:06:25+00:00Z
to 
As shown in the illustration, the assembly includes a 
tank which is filled with water to support the table. The 
bottom part of the table has nine square chambers. The 
middle chamber on each side admits an airhose for air 
pressure control.The table is centered in the tank by 
four rubberbands attached to its corners. 
The air pressure in the chambers is controlled for two 
reasons: first, to maintain the table constantly level and, 
second, to keep the table from submerging too deeply or 
rising too high in the tank. 
Table level is controlled with two pendulum air 
bearings which are mounted on the adjacent sides of 
the table (sides I and 4 in the illustration). The air 
bearing on side 1 is electrically connected to the solenoid 
valves on sides 2 and 4, while the air bearing on side 4 
is connected to solenoid valves on sides 1 and 3. 
Therefore, when the table is offset from the horizontal, 
one or both of the bearings will activate the respective 
solenoid valves to allow air pressure into the proper 
chambers. 
In addition to the horizontal level control, the 
assembly includes a depth switch (not shown) which is 
mounted on the bottom of the tank. The switch 
generates a signal when the table immerses too deeply 
or when it rises too high in the tank. This 'signal 
controls the solenoid valves on all four sides simul-
taneously, either to allow additional pressure to raise 
the table or to evacuate the pressure to lower the level.
Note: 
Requests for further information may be directed to 
Technology Utilization Officer 
Marshall Space Flight Center 
Code ATO1 
Marshall Space Flight Center, Alabama 35812 
Reference: B74-10144 
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 develop-
ment should be addressed to: 
Patent Counsel 
Marshall Space Flight Center 
Code CCO1 
Marshall Space Flight Center, Alabama 35812 
Source: J. L. Burch
Marshall Space Flight Center
(MFS.22039)
S 
B74. 10144	 Category 06


Self-leveling load table

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