TEMPORARY VIBRATION FIX FOR THE(Sanitized)1540 LIGHT TABLE

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B05171A000400030019-0
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 6
• Document Creation Date: December 28, 2016
• Document Release Date: June 6, 2005
• Sequence Number: 19
• Publication Date: August 31, 1971
• Content Type: MFR

Approved For Release 2005/06/23 CIA-RDP78B05171A000400030019- ~,
SUBJECT: Temporary Vibration. Fix for the
Table
U 0:
NPIC/TSG/ESD/TEB-124/71
31 August 197.1
1.540 Tight.
1. On 21 July 1971, IEG, solicited
the aid of ESD to alleviate the effects of vibration on the
11540 Light Table. is currently
working on a permanent solution to the problem but their
results will not be available for several months.
was hoping that ESD could provide some aid in the meantime.
Contained herein are the results of ESD's efforts.
2. IEG, was selected as a PI
with more than average Vibration problems with his
1540 Light Table. He was questioned to insure that he had
followed all recommendations to minimize vibrations (i.e.,
a slight tilt to the table, table close to building column,
and operator not in contact with table during high magni-
fication operations). then indicated that he
was most aware of vibration when he was studying a particu-
lar image for an extended period of time. An obvious
solution in this case would be to provide direct coupling
between the microscope's objective and the film stage. A
wedge was glued to the top surface of a hold down ring and
when vibration-free viewing was desired the wedge was
placed in contact with the rhomboid'arm. All image motion
was stopped at the expense of convenience and maneuvera-
bility. This solution is completely unacceptable for
scanning operations.
The next approach was to provide isolation of
the entire table from the source of vibration. Isolation
pads were :placed under the wheels of. light table.
Although is satisfied with this solution, most
other PI's,are not. Isolution pads.flexible enough to
attenuate 15 Hz frequencies, also cause the table to sway
freely. In addition, any contact with the table, by-
passing the isolation pads, causes vibrational motion to
continue. _?
Declass review by NGA/DoD
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SUBJECT: Temporary Vibration Fix. for the
Table
The next approach was to stiffen the bridge beam.
Theory states that a "closed box" beam is more rigid than
a "C" beam. An idealized case would be to replace the
"C" beam. This is the solution that has
chosen. A compromise to this solution is to c ose the
beam only part way. By clamping a 3/8" aluminum plate
to the open side of the bridge beam, vibrational image
motion is reduced significantly. This solution appears
to solve vibration problems with a minimum amount of additional
limitations created. Three vibration attenuation kits
have been fabricated and are being used by PI's in IEG.
(Section 3) describes the kit and discusses its operational'
limitations.
3. The vibration attenuation kit consists of one
aluminum plate (9" x 5" x 3/8") clamped to the microscope;:.'
carriage bridge beam either on the left hand or right
hand side. The plate is fastened.'to the beam by four-'
'C"-clamps. Figures 1 and 2 show the kit attached to the
right hand side of an 01540 Light Table. Attachment
of the kit does not require any permanent alterations
to the existing light table.
The only limitation to this solution is the re-
duction in surface area the microscope can cover. The'' addition of a 9 inch plate to the right hand side of the
bridge beam restricts the carriage assembly to 5 inches
of travel to the right from center. A 9 inch plate, attached
to the left hand side, restricts carriage motion to 5 inches
left of center. The area of the viewing surface used '."
by the PI is a function of which.,hand he writes with."
"
'A
right handed PI normally uses the left hand side of the
viewing area for monoscopic viewing and the center for
stereoscopic viewing. The right hand viewing area is
used as a writing surface. A left.handed PI is just the
opposite. There has been very lit=tle complaint by PI's
who have the kit attached to their'table. The only complaint'
was by a PI who had a little trouble using his grid overlay:
He was able, though, to adjust theiimagery such that he.
could use-the grid. The overall impression of those PI's
involved is that they would gladly give up. viewing area,
seldom used, to stop image motion.
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 Approved For Release 2005/06/23 CIA-RDP78B05171A000400030019-0
25X1
5X1
SUBJECT: Temporary Vibration Fix for the
Table
1540 Light
4. This solution to the. vibration problem is offered
as a temporary fix until makes their more rigid
bridge beam available. It is, however, possible that this
fixrshould-the fix prove to be not economically
feasible. ESD will supply design drawings and additional
information for those who are interested.
25
25
5X1
Test Engineer
TEB/ESD/TSG/NPIC
Distribution:
Original - NPIC/TSG/ESD/TEB (Chrono)
1 - NPIC/IEG/OD/Ch
1 - DDI/IAS/Tech. Adv.
1 - Army/SPAD
1 - NPIC/TSG/
1 - NPIC/TSG/RED/SDB
1 - DIA/DI-8 (Tech 8, Dev r
1 - NPIC/TSG/ESD/EPB
25
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Figure 1: Front view of an 1540 Light
Table with a Vibration At gnu ton
attached to the rig'~~p~l$ FV Ileae5/06/23 : CIA-RDP78B05171A000400030019-0
carriage beam.
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CAUTION -DANGEROUS VOLTAGE
Figure 2: Rear view of an 1540 Light
Table with a Vibration Attenuation Kit
attached to the riglAtpp}& ft~el&set 5/06/23: CIA-RDP78B05171A000400030019-0
carriage beam.
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