DEVELOPMENT OF A SIGNAL ACTUATED DEVICE AND A TIME EVENT MARKER FOR A MINIATURIZED RECORDING SYSTEM

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03424A000400040012-2
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 21
• Document Creation Date: December 27, 2016
• Document Release Date: April 30, 2014
• Sequence Number: 12
• Publication Date: February 15, 1958
• Content Type: REPORT

Declassified in Part- Sanitized Copy Approved forRelease2014/05/01 : CIA-RDP78-03424A000400040012-2
Q--45-11"4-PI-zar_ A x_
4 T"13
DEVELOPMENT OF A SIGNAL ACTUATED DEVICE AND A TIME EVENT MARKER FOR A
MINIATURIZED RECORDING SYSTEM
TABLE OF CONTENTS
Paragraph No,
Page No.
1.0
Introduction
1
2.0
Summary of Prototype Components, TEM
1
3.0
Difficulties Encountered
2
3.1
In Differential Gearing
2
3.2
In Bending of Ratchet Shafts
4
3.3
In Wobble in Printed Circuit Discs
4
3.4
In Adjustment of Printed Circuit Discs
and Contact Fingers
5
3.5
In Dynamics of Operation
4.0
Operation of Calendar Driving Solenoids
11
4.1.1
Necessity for Change to Solenoid Drive
12
4.5
Solenoid Design Considerations
13
5.0
Printed Circuit Information
16
5.1
Printed Circuit Plate
16
5.2
Contact Finger Mounting and Material
16
5.3
Printed Circuit Mounting
17
5.11
Watch Movement Mounting
18
z�.0
Selection of Power Supply, TEM
18
7,0
General Status of S.A.D., Project 74B
19
Figure I � Block Diagram
20
���, Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
1
1
1
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
DEVELOPMENT OF A SIGNAL ACTUATED DEVICE AND A TIME EVENT MARKER FOR
A MINIATURIZED RECORDING SYSTEM
1.0 Introduction
1.1 This report covers the status of work on Project No. 74
to February 15, 1958.
1.2 All of our effort has been concentrated on TEM System NB".
This system was described in Paragraph 3.0 in the report
for work ending October 31, 1957.
2.0 Summery of Prototype Components, TEM
2.1 Negator Spring Drive to provide power for a watch used as
the time base. This mechanical power source will be hand
wound and will be used to power the watch only. This spring
drive is identical to that used on a previous project.
2.2 The watch will have a once/minute contact to operate the
calendar portion of the system by providing pulses to the
units-disc calendar drive-solenoid.
2.3 Separate solenoid and ratchet systems will be provided for
each of the digits disc's, three in number. The first disc
stores units information, while the second and third discs
store 10's and 100's information, and 1000's and 10,000's
information, respectively. In this calendar portion, the
printed circuit discs are face down toward a printed cir-
cuit plate, on which are mounted the contact fingers which
ride against the disc lower sides.
2.4 A TEM sweep bridge which reads out the coded calendar informa-
tion stored in the three discs is also operated by a solenoid
-1-
-- Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
�
and ratchet system. Here, the movable portion is a' bridge
carrying the contact fingers over a commutator arrangement,
the contact segments themselves being stationary and arranged
circularly around the bridge. These segments are connected
by printed circuit to their corresponding tie-in points with
the calendar contact fingers.
2.5 A transistor multivibrator system is used to provide 10
pulses per second to the TEM sweep drive solenoid, upon
reception of an external sweep command. This multivibrator
is encapsulated and mounted on the TEM unit.
2.6 The necessary resistors and capacitors needed (see Section
4.1 and 4.2) for proper calendar solenoid operation are
mounted both on the printed circuit plate and on the bottom
plate of the assembly. Internal connections are made by
stand-off terminals with feed through connectors.
2.7 External connections are made through an amphenol connector
of a similar type to that used in a previous project. This
connector will have a clamp to secure a mating plug and
cable, since a cable system of connections between units
is desired.
2.8 The watch movement used as a time base will have a mechanical
hack arrangement for starting the time base, very similar to
the arrangement used in a previous project.
3.0 Difficulties encountered which have delayed progress are:
3.1 An internal differential gear system was originally con-
templated, as shown in the block diagram, Figure 2, report
of August, 1957.
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2 _
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
A reasonable investigation did not show any source for such
small assemblies as would be necessary here. Differentials
of various types have been used in Other fields, such as
radar servo systems, but the power involved is of a radi-
cally different order of magnitude.
In such cases, also, the primary consideration is close fit
with no back lash, with less emphasis on the power required
to overcome the friction of the sliding faces involved. Our
experience has been mainly confined to straight gear trains
always under compression, in which backlash-is not a problem.
After considerable study of a completed assembly, we concluded
that we do not, at present, have the total facility for pro-
ducing a satisfactory differential gear assembly.
3.1.1 A parallel development had been carried along using
a magnet drive for each of the separate calendar discs
in TEM as a safeguard against such insurmountable diffi-
culties with the differential system This latter sys-
tem also presented difficulties, of course, in the solu-
tion of the various mechanical and electrical problems
encountered. All of these problems seemed solvable
with a reasonable amount of engineering expenditure, and
at the time of writing, most have been solved, as present
satisfactory testing of a nearly completed prototype
attests. The latter method of drive, therefore, has
been adopted.
-3-
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
3.2 Shafts used with the solenoid drive system are longer than
in usual watch work, and in general, the power which must
be delivered through them by ratchets to overcome inertia�
and contact finger friction on the printed circuit discs
Is considerably greater than the -power needed by a watch.
Consequently somewhat heavier staking for assembly of The
ratchet to the shaft was necessary, but bending of the
shafts during the staking operation with resultant wobble
of the printed circuit discs mounted on the shaft ends
proved to be a problem; a solution was found by enlarging
the transverse shaft cross section and tempering the shaft.
3.3 The printed circuit coding discs are "outboard" mounted,
SO that each must be mounted on a portion of it ratchet
shaft smell enough to go through a bearing used to support
the shaft. It is difficult to obtain true transverse
mounting here clue to this small shaft-end cross-section.
This added to the eroblem of shaft wobble causing wobble
of the printed circuit disc. Wobble of the printed circuit
disc is extremely undesirable because it changes the contact
pressures of the printed circuit contact fingers and also the
point of contact of these fingers on the disc. This wobble, then
reduces the alignment margin needed to absorb other uncontrollable
variables in positioning.
Some difficulty was experienced by our supplier of printed
circuit discs, so that the original lot of discs was unsatis-
factory and had to be replaced. Since discs were received
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
approximately two months after we had scheduled them,
considerable delsy was experienced in the development
of good_ contacts from these discs: the problem of ob-
contacts
taming eleven consistent/running on paths .090 inches
wide with 100 stens per revolution is not a simple one.
3.4 Considerable analysie of the problem of assembly of these
contacts into proper relative positions maintaining high
electrical conductance to the disc, has been made. Origi-
nally we had contemplated the use of adjustable contacts
to allow individual contact tangential alignment after
the contact system was in position. However, some study-
showed that the lengths of individual contacts could be
controlled accurately enough to eliminate the need for
the more complex adjustable contacts. Furthermore, it
was felt that the introduction of a tangential adjustment
would render more difficult simultaneous adjustment in
height (which determines contact pressure) and in radius,
(which determines position of contact from center of printed
circuit disc).
3.4.1 To aid in contact adjustment, a transparent disc has
been fabricated which is equipped with scribed lines
defining the circular paths and relative angular
positions of the ends of the contacts. This disc
is first placed on the shaft to check the contact
alignments before the printed circuit disc is
mounted. Then, when the printed circuit disc has
been assembled to its hub, the contacts should
meet the disc In the proper positions. To check
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
3.4.2
us e-eL FT
ht
at' i-ft.tk-(
proper assembly of printed circuit disc and hub,
the assembly is rotated on an optical comparator to
determine the radial eccentricity, if any, of the
disc relative to the printed circuit.
The. final adjustment of the printed circuit disc/to
obtain precise angular alignment to the contacts is
made with an electrical check as follows: 4 small
brass block with two scribed lines on it/ insulated
on its lower side, is placed on the printed circuit
in such a way that the scribed lines/are level with
and adjacent tb a radial line scribed on the back
A
of the printed Circuit disc. The two scribed lines
k
on the block correspond to one,complete motion of
the disc, a hundredth part (;14' the circle. One mark
on the block is aligned with the disc mark when an
outer-most contact is\jn(t "making". The other mark,
ui
then, corresponds to the same contact Just "breaking".
The solenoid is noW_pulsed from the test input until
one disc revolution is Made. If disc adjustment is
correct, the disc mark will\etop half way between the
block marks, ,�since this indiCates the disc contacts
\
are stopping, after each pulse,\with the contact
finger ends midway across the contacts. If not, the
three screws holding the disc are loosened, the disc
is rotated slightly in the proper direction against
the ratchet, which is held, and after the screws are
-6-
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2 -
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
retightened, the solenoid is pulsed to put the disc
through one revolution, and a check is made to see
that the disc mark falls half way between block
marks. This procedure is repeated until precise
alignment is obtained.
3.4.3 Some slight variations have been found in the printed
circuit discs which were not expected and which are
evidently due to machine-dividing errors in the
original master disc made by the supplier, although
the errors discovered could also have been due to
poor photographic technique in producing the master.
3.5 The operation of the printed circuit with the solenoid type
of operation introduced dynamic problems (see Section 3.1.1).
These problems were (a) a means of returning the solenoid
plunger to its rest position. (b) a means to prevent the.
plunger from rotating in the solenoid housing when the coil
was energized. (c) a means to prevent the force of the sole-
noid from rotating the calendar disc and TEM sweep bridge
more than 3.6 degrees and 24 degrees respectively; that is,
a means to prevent overtravel of the driven system.
3.5.1 The solenoid was designed with a spring coiled loosely
about the driving arm, which is actually an extension
of the plunger. One end of the spring rested against
the plunger, while the other end pressed against a
slotted pin fastened upright to the solenoid mounting
bracket and in line with the driving, arm, The purpose
-7-
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
of this spring was to return the plunger to its rest
position.
The coil spring was designed to have a force of about
2 grams in its normal rest position and about 3 grams
in its normal compressed position. This was calculated
to be sufficient to return the plunger to rest regard-
less of orientation of the unit, since the plunger
itself weighs about 0.8 grams.
The coil Spring had a tendency to buckle in its middle
when the solenoid was energized. As the spring buckled,
it would seize the driving arm and cause a malfunction
of the solenoid. Sometimes this malfunction showed
up as a failure of the plunger to close fully and
sometimes as a failure of the plunger to return to
rest.
3.5.1.1 A new spring was designed to overcome this
difficulty. This new spring, made of pre-
tempered Tagiloy special alloy strip, is a
single leaf spring and is fastened to the
top of the solenoid mounting bracket by a
single screw. An elongated hole is provided
in the spring for pre-tension adjustment.
From the mounting screw, the spring comes for-
ward, is looped back and bent down to rest
against the plunger nose. The spring is
�
_ Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
slotted in order to straddle the driving
arm.
This' spring was adjusted to give a force of
1.8 to 2.8 grams when the solenoid is in the
de-energized position and with the plunger ad-
justed to a gap of .0201. When the plunger is
fully closed, the spring has a force of 6 to
8 grams. This force is not disturbing since
the plunger can counteract a restoring force
of 65 grams when closed fully by the energized
coil.
Thi. design proved very successful. There were
no malfunctions in any tests that could be attri-
buted to this design.
3.5.2 The action of the solenoid when energized occasionally
imparted a slight twist or rotary motion to the plunger.
The slotted pin mentioned in 3.5.1 also served as a guide
to prevent this, but .the rotary motion of the plunger
caused the driving arm to rub on one side of the pin,
in turn causing excessive friction which contributed
to the malfunction outlined in 3.5.1.
3.5.2.1 This fault was corrected simply by putting a
.018" diameter hole in the outer portion of
-9-
I __ Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
the plunger working face and pressing .015"
diameter brass pin into the back end of the
solenoid housing EO that it extended through
the hole in the plunger face.
Results showed no malfunctions in any tests
that could be attributed to this design.
3.5.3 Upon assembling the solenoid in the unit with the
ratchet wheel, shaft, and calendar disc, it was found
that the force of the solenoid would cause the calen-
dar disc to travel inertially further than the required
3.6 degrees.
3.5.3.1 The problem here was to prevent this overtravel
without increasing theclosing-load on the
solenoid as would be the case if, for example,
a stronger detent spring were added.
.The problem was solved by adding a stop pin as
close to the ratchet wheel as possible and in
such a position that the driving arm would be
pressed between the pin and one tooth of the
ratchet wheel, preventing any overtravel motion.
The result was a positive single step operation
without overtravel of the calendar discs. Work
is still being done, however, to minimize the in-
ertial effects of the TEM sweep bridge and asso-
ciated gear train.
1 n
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
4.0Operationvic)..B./.. drivi& solenoids
_.
4.1 These solenoids are pulsed through series capacitors when
their respective circuits are closed. The capacitors are
charged rapidly, thus limiting average operating currents
to small values even though the circuits may remain closed
for substantial times. Then, when the circuit is opened,
the capacitor discharges through a high resistance connected
across it, at a rate which insures a discharge of 5 time-
constants by the time the circuit is reclosed for another
solenoid pulse.
4.2 The units disc solenoid is operated through once/minute watch
contracts, while the next two solenoids are operated through
the printed circuit discs and corresponding contact fingers.
In any case, the contact fingers do not carry current during
"make" (due to inductive delay in build up), and carry only
micro-ampere levele during "break" (due to capacitive charging),
and so contact life is not shortened by any arcing affects.
4.
Detailed analysis has been made of this current pulse opera-
tion, which is basically a series R-L-C circuit energized by
DC voltage at t c. The'L and R are determined by the sole-
noid itself, and the value of C stems from"energy needed" re-
quirements. Too large a capacitor, supplying excess energy,
causes unnecessary battery drain and too small a capacitor
will not yield enough energy under the current pulse to
operate the solenoid. Also, if the nominal C is neer or
below the critical value, the change of energy input with a
small change in capacitance becomes appreciable, and circuit
oscillation may occur. The actual capacitance and resistance
-II-
- Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
vary with temperature: in order to insure operation under all
-temperature conditions a value of C equal to 180% that of
critical was selected, using capacitors with manufacturing
tolerances of plus or mihus 15%.
4.4 Necessity for change to solenoid drives from the original es-
capement type watch was brought about by the following consi-
derations:
4.4.1 Assume that a contact disc is mounted on the escapement
shaft of a watch.. The normal mainspring must then be
strengthened so that it must drive not only the watch,
but also the printed circuit discs. This introduces
both static and dynamic mechanics problems.
4.4.2 Consider for the moment only the comparatively static
problem arising when the escapement stops against its
banking pin in one position or the other. Here, in
the normal operation of a watch, the pallet stone angle
is such that its escapement is locked by the force of
the gear train. When the balance wheel returns from its
furtherest excursion and before it unlocks the escapement
wheel, it first backs this wheel and the gear train up
a small amount. 'Normally this action is readily accom-
plished, but if the mainspring pressure has been greatly
increased (to overcome the added resistance of the con-
tact disc springs), the force required to unlock it is
also increased. However, when the pallet fork is over
and locked against the escapement wheel tooth, there is
no longer any friction drag from the printed circuit
-12-
- Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
disc. Consequently the mainspring's total force
(which might be several times that required to
operate the escapement alone) is now locking up the
pallet fork so that the work to be done by the
balance wheel when it returns is much larger than
would normally be the case. If it does unlock the
pallet fork, however, so that the escapement wheel
drives the balance wheel, the escapement wheel must
immediately take up the friction load of the contacts
on the printed circuit disc while it is delivering
power to the balance wheel in.such a manner that the
balance wheel .is not overbanked.
4.4.3 Because of the foregoing, the seriousness of which being
previously overlooked, attention has been turned to a
new drive system using solenoid and ratchet drive assem-
blies. This latter system has subsequently been in-
corporated in the prototype TEM unit.
4.5 Solenoid design considerations
4.5.1 Tests showed that the shaft of the first solenoid design
was saturating at the ampere-turn levels necessary to pro-
vide sufficient mechanical output to overcome the inertia '
and static frictioi of the load. Furthermore, calculation
indicated considerable energy was being lost at the top
air gap of the solenoid, which is a non-working gap.
4.5.2 Solenoid plunger saturation at working ampere-turn levels
became evident from (a) examination of plotted data, pull
(in grams) vs. ampere turns applied, where the pull needed
- Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
is obtained at the cost of greater and greater ampere-
turn increments; and (b) measuring flux in the plunger
by means of a pick up coil and comparino: the corresponding
calculated flux density with the curves for the 4750
steel, which curves are supplied by the manufacturer.
It -i,;as desired to operate at incipient saturation, since
above this point energy is being sup-nlied at diminishing
utilization (as outlined above) are below this point
plunger shaft cross section becomes unnecessarily large,
which, in turn, results in (a) unnecessary increase in
solenoid volume, and (b) decrease in the coil constant,
Ge, for the solenoid coil. A decrease in this coil
figure of merit results in decreased overall efficiency.
In view of the above, a new solenoid was constructed of
relay steel +5, having the same dimensions as the origi-
nal solenoid of 4750 steel. Now at a flux density of
fifteen kilogauss (the value needed to produce forces
large enough to overcome the load), 4750 steel has a
high magneto motive force per unit length (being highly
saturated), whereas relay steel 445, for this same flux
density, has a relatively low mmf gradient corres-
ponding to incipient saturation. Tests of the new
solenoid confirmed the above; operation was shifted
to plunger incipient saturation. Therefore, relay steel
#5 was adopted in lieu of 4750 steel, and the solenoid
-- Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
dimensions remained unaltered.
� 4.5.3 Regarding the top air gap; calculation indicated this
gap to be 15% of the maximum solenoid gap. However, a
reduction of the reluctance of this gap was complicated
by several factors; reductions to the 'second power of any
increase in plunger shaft cross section would be desir-
able from this viewpoint, but undesirable from other
considerations, (see above). Therefore, a reduction to
the first Dowerof a dimension change was used. This
could be effected either by increasing the axial dimen-
sion of gan face (thickening the housing and lengthening
the shaft accordingly) or by decreasing the length of the
gar itself. This latter was down to .00071 nominal already
and any further decrease not only would entail machining
complications, but would also enhance any-tendency toward
radial pull (seizure) present due to eccentricity of fit,
since for .a given eccentricity, the radial pull increases
as the length of the-gap decreases. In view of these
considerations, the former method of decreasing tor gap
reluctance was tried. The solenoid housing thickness
Was increased 110%, with a correspond decrease in top
gap releietance. This was verified during test of the new
configuration by noting the pull-in force to be 15% higher
than previously, for a given coil current.
4.5.4 This work is still in progress. Other solenoid design
-15-
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
� problems still under investigation are:
(a) Magnitude of electrical losses due to circulating
current in brass coil bobbin.
(b) Reduction of radial pull at to air gap due to
minute eccentricities in fit of plunger, bobbin
and housing. .
(c) Coil configuration and wire size agreement to pro-
duce ampere turns per volt ratio yielding operation
at incipient saturation.
(d) Use of modified circuitry to prevent the heavy sole-
noid current pulses from passing through the power
source.
(e) Development of higher-power solenoid as an alternate
method of winding the time base, to allow elimination
of the negator spring.
5.0. Printed Circuit information
5.1 The printed circuit used for TEM consists of an epoxy plate .030"
thick with printed circuitry on both sides. Since this is mounted
against a brass plate, the printed circuit must first be insulted
by a spacer or shim. For this purpose, a .010" epoxy sheet has
been cemented to the brass plate. The holes in this sheet for
bringing through the upper ends of the ratchet shafts have been
cut oversize to prevent any adhesive (dhich is used to bind the
epoxy sheet to the brass plate) from being squeezed into the
ratchet shaft bearings.
5.2- The posts for the contact fingers are fastened to the .030"
thick epoxy printed circuit plate. The contact post consists
of a headed cylinder with an internal thread in the smaller
_1 4_
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
diameter. This post is a screw machine part in stock from a
previous project, reouiring a spacer�to permit the screw
(which is threaded into the bottom of this headed cylinder),
to clamp the cylinder tightly to the printed circuit plate.
The twin contact wires are staked into parallel slots in the
head of this cylinder, which is on the top, or disc side, of
the printed circuit. After adjustment of position (see Sec-
tion 2.4), the wires are soldered to the machined part to in-
sure high electrical conductivity and mechanical rigidity.
5.2.1 Most of the contact wires for the prototype are of
special gold alloy designated
which, al-
though yielding excellent contact conductance, has
a slight tendency to wear against the disc. The units
calendar disc, therefore, receiving ten times the wear
of the next disc, has been fitted with .005" contact
wires of hardened Paliney #7 alloy, (a harder substance
than C-12), to reduce wear. This material also shows
excellent contact conductance for like contact pressures,
but because of its 20% higher co-efficient of elasticity,
similar pressures (1 gram per wire) are obtained at
smaller downward deflections of the printed circuit
disc. .This effect slightly increases the load on the
drive solenoid for the same downward deflections of the
printed circuit disc. However, tests show that sufficient
solenoid force is available.
5.3 First samples of this printed circuit plate show considerable
bowing, convex upward, across the plate's width dimension. As
:17-
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
STAT
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
this deviation is approximately .018", appropriate places
have been found for additional screws on the layout to hold
the printed circuit down solid. against the lower plate. Be-
cause the printed circuitry on the bottom of the printed cir-
cuit plate projects about .002" out from the bottom face of
the plate, all hold-down screws are equipped with .002" washers
placed on the screws between the printed circuit Plate and the
epoxy spacing plate.
5.3.1 In future units, this will be accomplished by incorporat-
ing support pads directly to the bottom side of the printed
circuit plate.
5.4 In the previouslycontemplated configuration, provision had been
made for a viewing hole in the printed circuit plate so that the
Balance Wheel of the watch could be observed. This introduced
complications in construction of the printed circuit. In the
present TEM unit, wherein the negator spring drives nothing but
the watch (see Section 4.3).the watch is mounted in a drawer
which is pushed into the unit. This is similar to the drawer-
mounting used in a previous project in which various components
were drawer mounted. In the present TEM unit, therefore, the
watch is not only observable. (from the bottom of the unit), but
is also accessible from both top and bottom when the drawer is
pulled out. The once/minute watch contacts are thus also
readily accessible.
6.0 Selectionof Power Supply TEM
6.1 Careful attention must be paid to the selection of power supply
for operation of the TEM prototype. A battery capable of handling
-18-
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
50 ma pulses of current with no more than 10% fall in terminal
voltage during delivery of current, must be used. �
6.1.1 Also, for the prototype. _crteaiia a battery potential of
nine volts open circuit should be used during actual
unit operatIon. This should be reduced to six volts,
however, when a solenoid is pUlsed directly through its
test input position, as otherwise the solenoid will be
overpowered and damage to the coil and/or driving mem-
bers may result.
6.2 In all subsequent TEM units, a battery open circuit voltage of
six volts will suffice during actual oljeration since the latest
solenoid design has an ampere-turns per volt ratio which brings
operation down to the six volt point.
6.2.1 Unless specifically stated in a future report, the power
supply needed for future units mast still pass the peak
currents outlined in Section 6.1 above.
6.3 Detailed investigation of shelf life, ampere hours per unit
volume, change of voltage with temperature, peak current capa-
bility, etc., of various types of miniature electromotive cells
is presently in progress. This is being done with a view toward
recommendation of the best type and size of cell compatable
with the requirements of this project.
7.0. General status of S.A.D.. Project 741
7.1 The printed circuit plate has been ordered from a supplier and is
being awaited.
7.2 All machined parts for this unit are completed.
7.3 The modified watch movement and hack mechanism for this unit
are presently being fabricated.
-19-
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
I
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2
0
Cl CT :1--�
,
1
c:DOLeNOID
I 4.
L.; 7
7.2) .
21; ,k_4i
Lai3_.L4 L,1)1
tO loo
, C
,5 o Le Kin
)
(2 P

jI
HC)
TEO 71401-1S A,NOS!
DISC.
3t 4 21 3)
" 1;1 .
0 0 0 X 1 0 4 0 0 0
4 CD / r
'
TA,L1 LT
A
Declassified in Part - Sanitized Copy Approved for Release 2014/05/01 : CIA-RDP78-03424A000400040012-2