Working platform and collapsible basket facilitate entry of men with equipment into the overhead manhole of a deep tank. A winch and pulley rigging hold the basket which is suspended in the manhole. The basket is suspended at three points without the rig impinging on the area of the manhole

Ehrhardt, W. R., Jr.

English

NASA Technical Reports Server

July 1969	 Brief 69-10180 
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. 
Space-Saving Hoist for Tank Manholes 
The problem: 
The area of an overhead manhole of a deep tank is 
often severely limited for the passage of men and 
equipment. Access is still-further restricted by the 
rigging and operation of a hoist. The need for men 
with equipment to enter and clean the fuel and oxidant 
tanks of the Saturn II is an example of this difficulty. 
The solution: 
A working platform is rigged, above and clear of the 
tank (which is vulnerable), having a square hole in its
center directly over the manhole; the dimensions of 
the hole equal or slightly exceed the diameter of the 
manhole. On the platform a winch (powered or man-
ual) is mounted opposite the center of one side of the 
square hole where a pulley is fixed that leads over the 
edge of the hole. A pair of pulleys, one at each of the 
two corners of the hole that oppose this pulley, are 
mounted leading both toward each other and down 
through the hole. 
The collapsible basket (or bucket) used consists of 
a steel ring, at its top, to which the fabric sides and 
(continued overleal( 
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.
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bottom of the basket are roven; inside the bottom of 
the basket is a fiberglass disk. At each of two of three 
equidistant points on the top ring of the basket an 
idling pulley is mounted; at the third point will be 
fixed the end of the winch's cable. 
From the winch the cable is laid over the nearest 
pulley on the platform; roven through one idler on the 
basket, through a guard tube between the idlers, 
through the second idler, and through the pair of 
opposed pulleys on the platform; and made fast at 
the third point on the periphery of the basket. Thus 
the basket is suspended at three points without the 
rig impinging significantly on the area of the man-
hole. One may enter the basket by ladder. 
For many industrial applications the rig could be 
much simpler, especially when the top of the tank is 
robust enough to bear men and equipment. Then 
there would be no need for a platform. The first pulley 
could be dispensed with; the winch could be clamped 
at the edge of the manhole, at one of three equidistant 
points on its periphery; and the other two tank-top 
pulleys could be clamped at the other two equidistant
points. Alternatively the winch could be mounted on 
a portable steel tripod or other frame directly over 
the edge of the manhole. 
Notes: 
I. This information may interest oil, shipping, or 
railroad companies; and producers of chemicals, 
gas, or electricity. 
2. Documentation is available from the: 
Clearinghouse for Federal Scientific 
and Technical Information 
Springfield, Virginia 22151 
Price $3.00 
TSP69-10 180 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: William R. Ehrhardt, Jr. of
North American Rockwell Corporation 
under contract to
Marshall Space Flight Center
(M FS- 16508)
. 
is 
. 
Brief 69-10180	 Category 05


Space-saving hoist for tank manholes

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