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Патент USA US3095805

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July 2, 1963
3,095,795
H. W. YATES
CAMERA SHUTTER
Filed June 8, 1960
2 Sheets-Sheet 1
INVENTOR.
HÄROLD Y/)TES’
“Mmm
ATTORNEY
July 2, 1963
3,095,795
H. W. YATES
CAMERA SHUTTER
Filed June 8, 1960
2 Sheets-Sheet 2
.In
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_
IÑVENTOR.
/ÍÄÑÓÁD YATES
BY
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ATTORNEY'
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3,095,795
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cause the solenoids respond almost instantly to time im
pulses or signals and the widest variation of periodic pat
tern is possible.
In the case of the nose cone re-entry which is being
in diagrammatic form in FIG. 4. It consists of an addi
tional series of overlapping blades 14 mounted on shafts
carrying small pinions 15 which revolve around a large
gear 16.
These blades constitute an auxiliary or addi
described the actuation of the solenoid 5 is synchronized Ul tional shutter or diaphragm in series with the main shutter
and are shown separately in FIG. 4. lf the blades are
to time, and timing marks may be placed on the film by
actuated to give one or more revolutions throughout any
any suitable means in synchronism with the timing signals
lMarking a film with time indicia
one-second actuation of the main shutter, there will be a.
A number of methods have been proposed
continuously varying exposure with each main shutter
position from all the way closed, shown at the left of FlG.
4, through partly open, at the center, to wide open, at the
actuating the solenoid.
is not new.
such as the flashing of Ia neon light along the edge of the
film or other means which will give marks on the photo
graphic emulsion. As the particular method of forming
right.
When the nose cone is first making its re-entry and so
has very low brilliance, there will not be sufficient energy
solely for the purpose of pointing out that the operation 15 in the second when the main shutter is partially open,
but during the second when it is wide open there will be
of the shutter may, and normally will, be synchronized
one or more cycles of exposure from zero to wide open.
with such conventional time marking.
In the beginning at the wide open point, there will often
After the object has passed the field of View of the
be sufiicient energy to produce a narrow strip of usable
camera, the solenoid 5 is cut olf and a pulse actuates the
the wide open
solenoid 9. This temporarily withdraws the armature 8 20 spectrum one or more times a second
main shutter position. As the brilliance increases there
and permits the stop 7 to slide past it to the closed shutter
will be exposure times that lare right in each second and
position which is shown in FIG. 3. The closing impulse
this will remain true with maximum brilliance because
may be initiated automatically or manually as desired.
even at maximum brilliance the moving .auxiliary shutter
When the simple modification of the present invention
is used to produce a streak from a re-entering nose cone, 25 blades 14 reduce the opening periodically to a very small
figure. As the nose cone dies down in brilliance there
at the beginning when the cone is radiating very little
will only be useful spectral exposures during the wide
energy, the film will be completely underexposed at the
open intervals of the main shutter Ias is the case when the
predetermined shutter opening shown in FIG. l, but every
re-entry is starting.
second the wide open shutter will give suñicient exposure
With only the continuously moving blades 14- there
so that even in the beginning phase of the re-entry there 30
would be no accurate time marks and so an additional
will be some record part of the time, with the time cycle
larger blade 17 is provided with» `a counterbalance 1S and
described above every other second. As the nose cone
pinion 19 driven vfrom the main 'gear through the idler
increases in brilliance and/or cornes nearer there will
pinion 2.0. This blade periodically closes the shutter :and
begin to be a record during the periods when the shutter
is in the partially opened position shown in FIG. 1, and 35 it effects a much more rapid Iclosing and opening than
do the blades 14. As a result, periodic time marks are
in the position in «FIG 2 the exposure will become more
made near the open point of the secondary shutter. The
and more perfect. As the brilliance of the cone increases
time marks :and the relative exposure are shown in graphic
towards its maximum, the shutter opening on FIG. 1
form in F'lG. 5. The time marks are quite sharp and
begins to represent a more and more perfect exposure and
the position of FIG. 2 represents a greater and greater de 40 by synchronizing with the marking on the film a very
accurate determination of time is possible. `On the other
gree of overexposure. tlf the field of view of the camera
Ih‘and, FIG. 5 shows that the rise and fall of exopsure
is such that the nose cone remains -in it after it has been
effected by the blades 14 is more ygradual so that »at :all
markedly slowed down, the decrease in brilliance and/ or
times during the track there will be correct exposure for
increase in distance will repeat the situation `described
for the start of the exposure but in reverse order. After 45 a short time and, »as has been pointed out above, this
permits obtaining useful spectrograms throughout the
the nose cone has passed out of the field of View of the
passage of the object across the fieldA of view of the
camera, a pulse is applied to the solenoid 9 and the shutter
camera.
`
closes.
The modification of FIGS. 4 and 5 involves additional
It will be seen that by means of the present invention
moving parts although the moving parts do not require
there will be a record of the path of the nose cone through
precision manufacture and the gears may be made quite
an enormously greater range than is possible with a single
cheaply as there is no backlash problem. Nevertheless,
shutter opening and exact timing can be noted because
any ‘additional movi-ng parts involve some increased
the different shutter openings will result »in a different ex
maintenance problems and so when spectral data is not
posure for the portion of the track covered by them.
needed, the simpler modification of FIGS. l to 3 presents
Thus, at the start there will be a series of brighter and
advantages.
brighter dashes corresponding to the wide open shutter.
The ballistic cameras `of the present invention do not
Presently there will be both bright and less bright Ipor~
time marks on the film constitutes no part of the present
invention, it is not shown and has been described above
differ from standard cameras as far as the capability of
tions, the latter corresponding to the shutter position of
their recording surface is concerned. Ordinarily this
FIG. l. Then, for a very short period in the path, after
maximum brilliance has been reached, the track will again 60 means that the energy which is recorded must be in the
pass through the same phases in reverse order. The dif
ferent exposures can be sharply correlated with timing
marks of the film Where these are made and so the loca
tion and energy distribution at a wide number of points
in the track is satisfactorily recorded photographically.
For timing purposes the simple setup described above
will give an adequate record. However, where it is de
sired to obtain spectra at the various points by incorporat
ing a conventional dispersing means such as the grating
visible, ultraviolet or very near infrared to which photo
»gnaphic emulsions can be made sensitive. It is, however,
possible to provide a surface with a mosaic of infrared
)detectors or a 'converter tube which can be used .beyond
65 the range of infrared sensitive film. Mosaics for infra
red cameras are of course well-known and can be used
Without significant «change in a ballistic camera employ
ing the present invention. The sensitivity of mosaics of
infrared ‘detectors is considerably less than the visible
in the camera so that spectra are photographed on a dif 70 so much longer exposures may ‘be necessary.
«ferent part of the film from the main track, there may not
be a perfect exposure throughout the whole of the track. .
lf it is desired to have the best spectral record throughout
the whole track, a further modification of the present in
Converter
tubes have greater sensitivities more comparable to
photographic emulsions land within their response range
`constitute a useful modification. ‘Ordinarily the greater
sensitivity and compactness of photographic emulsions
vention permits this. {This further modification is shown 75 make them the preferred recording surface. However,
3,095,795
5
6
in unusual cases, 'for example where a re-entering nose
cone must be recorded against a bright ‘daylight sky, the
use of infrared detectors with suitable sky ñlters is worth
while. The particular recording `surface does not form
any part of the present invention and the above descrip
tion of surfaces other than films or plates is only for the
latching means to stop the closing of the shutter at
a predetermined aperture.
2. A ballistic camera acconding to claim l, provided
with overlapping obscurating means in series with the
purpose of .further illustrating the flexibility and versa
tility of the present invention. To suml up, it may be
considered that the present invention is useful with
cameras using any kind of optical radiations; that is
to say, radiations of wave length suñiciently short to obey
optical laws.
In the claims the term “solenoid” is used in its general
sense to cover an electromagnetic »intermittent actuating
means to produce a movement over -a limited path. The
tem is not used in the restricted sense =as limited to a
solenoid in which the armature moves only in a straight
line.
I claim:
shutter and means for moving the obscurating means con
tinuously through a range from substantially full obscura
tion to fun opening of substantially the same size as the
full opening of the shutter.
3. A ballistic camera according to claim 2 in which
the obscurating means «comprise -a series of rotating over
lapping blades, each ‘blade being `provided with a shaft
and a pinion and a movable .gear engaging said pinions
whereby movement of the gear causes each pinion to
rotate and to move the overlapping blades through ‘a
range from fully closed to wide open.
4. A ballistic camera according to claim 2 comprising
an additional obscurating means driven in syn'chronism
with the 4continuous obscurating means »at la rate to pro
duce periodic, very :short periods of obscuration.
1. In a ballistic camera having a radiant energy respon 20
5. A ballistic camera according to claim 4 in which
sive surface and wide :angle imaging optics, the improve
the additional obscurating means is driven to close the
ment which comprises
shutter opening .at a time when the continuously moving
(a) an iris type shutter centered on the optic axis,
obscurating means `are substantially wide open.
(b) electrically `actuated means for periodically and
substantially instantly opening the shutter- to a wide 25
References Cited in the ñle of this patent
open position against the resistance of rapid shutter
UNITED STATES PATENTS
closing means including Ia solenoid .and a linkage
Írom the solenoid to the shutter,
2,420,339
R'abinow ____________ __ May 13, 19‘47
(c) a stop on said linkage, releasable latching means
2,577,774
Lee ________________ __ Dec. 11, 1951
for said stop to hold the shutter partly open,
30 2,861,506
Leder ______________ __ Nov. 25, 1958
(d) a `solenoid ¿for releasing the latch, and
2,907,257
Schiks _______________ __ Oct. 6, 1959
(e) means for adjusting the position of said releasable
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