US3836233A

US3836233A - Anti-flash shutter with two compartments

Info

Publication number: US3836233A
Application number: US00211495A
Authority: US
Inventors: F Frungel; H Lohse
Original assignee: Individual
Current assignee: Impulsphysik GmbH
Priority date: 1970-12-24
Filing date: 1971-12-23
Publication date: 1974-09-17
Anticipated expiration: 1991-09-17
Also published as: FR2118917A1; SE372109B; DE2063888B2; FR2118917B1; DE2063888A1; BE776502A; CH539276A; GB1316537A; NL7117826A; IT946043B; CA962866A

Abstract

In a frame of the shutter an opening is provided for the passage of light, and at least three transparent plates extend across the opening to define with one another two compartments which the light must pass successively. Explosive charges are provided for opaquing both compartments simultaneously to thereby terminate the passage of light through the opening.

Description

United" States Patent 11 1 Friingel et al.

[ 11" 3,836,233 1*Sept. 17, 1974 ANTI-FLASH SHUTTER WITH TWO 5,342,540 9/1967 Abegg et al 350/160 R COMPARTMENTS 3,344,434 10/1967 Beckmann et a1....

3,409,909 11/1968 Scott et al 350/160 R 1 lnvemorsi Frank Friingel, Herwigredder a, 3,424,515 l/l969 Risk 2 Hamburg 56; Horst Lohse, 3,674,344 7/1972 Lacy Hamburg, both of Germany 3,721,172 3/1973 Frungel et al 350/266 [73] Assignee: said Frungel, by said Lohse m" Primary ExaminerRona1d L. Wibert Not1ce: The portton of the term of th1s patent subsequent to March 20, Assmam Examiner-Y MFGraw 1990 has been disclaimed Attorney, Agent, or Fzrm--M1chael S. Str1ker [22] Filed: Dec. 23, 1971 21 Appl. No.: 211,495 [57] ABSTRACT In a frame of the shutter an opening is provided for [30] Foreign A li ati P i it D t the passage of light, and at least three-transparent Dec 24 1970 Germany 2063888 plates extend across the opemng to define with one another two compartments which the light must pass [52] U S Cl 350/266 95/53 350/ R successively. Explosive charges are provided for 350/2673 opaquing both compartments simultaneously to 51 Int. Cl G03b 9/08, G021 1/28 thereby terminate the Passage 0f the [58] Field of Search 350/160 R, 266, 267, 312; openmg' [56] UNITE D SEFX F ES EgENTS 20 Claims, 4 Drawing Figures 2,489,751 11/1949 Candler, Jr. 350/267 f [111 l I 1 l 1 1 it 5 ];k 1u11111 d a V1254 llllllllllll'rl J/:(- '=u 5/ r1111 4 5 PAIENIED 3.836.233 sum 2 or 2 1* ANTI-FLASH SHU'l'lER'WITH 'rwo COMPARTMENTS BACKGROUND OF THE INVENTION The present invention relates generally to a shutter, in particular to an anti-flash shutter. Still more particularly the invention relates on an anti-flash shutter having closure times shorter than 100 microseconds, which is particularly suited for protecting the human eye against atomic flash.

Anti-flash shutters of the general type here in question are already known. Their purpose is to blacken or opaque the shutter cross section in a relatively short period of time, for instance by injecting into a chamber carbon powder orbe vaporization of electrically detonatable wires or the like. Such shutters are used where a rapid closure (against passage of light) of relatively large cross-sectional areas, for instance on the order of between substantilly 30 and 200 cm is required, which cannot be obtained with the necessary rapidity in any other way. Conventionally, such shutters have a single chamber and are usually provided with a unit composed of a charge of carbon powder and a small quantity of explosive, for instance nitro-pentane (Np) plus sulfur acid or lead-tricinate. When the explosive is detonated, usually electrically, it blows or injects the charge of carbon powder into the chamber from an edge zone of the latter, thereby opaquing or blackening the shutter. It is also known to provide two or more such units spaced circumferentially of the chamber, in order to obtain shorter opaquing times. This means that quantities of carbon powder are blown into the chamber from two or more locations, and this carbon powder usually adheres to the inner surfaces of the transparent plates -generally glasswhich bound the chamber.

It is also known from the prior art to use an explosive wire which, when detonated, will explosively vaporize with the vaporized material of the wire becoming deposited on the surfaces of the plates and opaquing the shutter in that way. Again, several such wires can be used per chamber.

These prior art constructions are fully usable for many of the intended applications. They do, however, have the disadvantage that if they are located at a relatively short distance from the site of a nuclear explosion, they will be destroyed by the heat generated during the explosion. At the very least, there is a danger that such shutters will become damaged under these circumstances and will not operate properly, thereby threatening injury to the eye of a viewer who happens to be using the shutter at the time the detonation occurs. Attempts have been made to overcome the problem by vapor-depositing a layer of gold on thesurfaces of the transparent plates, to act as a heat reflector. Unfortunately, the advantages obtained in this manner by the reflective capability of the deposited gold layer are more than overcome by the fact that the deposition of such a layer reduces the visibility through the shutter -which normally amounts to between substantially 80 and 90 percentto approximately 5 percent. Thus, the deposition of a reflective gold layer was found not to be the answer to the problem.

SUMMARY OF THE INVENTION It is, accordingly, a general object of the present invention to provide an improved anti-flash shutter of the type here under discussion which is not possessedof the disadvantages of the prior art.

An additional object of the invention is to provide such an improved anti-flash shutter which is capable of withstanding the heat flash generated during a relatively close nuclear explosion.

Another object of the invention is to provide such an improved shutter which can be produced inexpensively.

In pursuance of these and other objects which will become apparent hereafter, one feature of the invention resides in an anti-flash shutter which, briefly stated, comprises a frame having an opening for the passage of light, first means extending across said opening and defining at least two axially successive internal compartments through which light must pass successively, and third means for terminating the passage of light through both of said compartments simultaneously.

Such a shutter has the advantage that even if that chamber which faces towards the nuclear explosion is destroyed as a result of the heat flash, the other chamber will remain intact and provide the desired protection.

It is advantageous to utilize three substantially parallel transparent plates extending across an opening in the frame, the outer plates defining with the inner plate the two chambers. The opaquing means may be located in the region of the center or inner plate, that is in the region of the circumferential margin of the inner plate, with such means being electrically activatable.

The invention further proposes, according to another concept, that the frame itself be of an elastomeric material which is resiliently yieldable, and silicon rubber has been found particularly suitable for this purpose.

The transparent plates themselves may be of synthetic plastic material but, depending upon given optical requirements, they may also be made of glass which may or may not have special optical characteristics. The utilization of elastomeric material for the frame makes it possible for the shutter to yield, particularly to yield to the internal pressure which will suddenly occur in the chambers when the explosive charges or wires are detonated to blow the carbon powder into the chambers. This reduces the possibility that the shutter might become destroyed or damaged by separation of the margin of the plates from the frame with the consequent possibility that some or all of the opaquing material (E.G., the carbon powder) might vent to the exterior and prevent proper blackening of the shutter.

The opaquing itself, that is the injection of opaquing material into both chambers, takes place symmetrically which means that the center or middle plate can be made of a different material than the two outer plates. Thus, this material of the center plate need not be resistant against shock waves resulting from the detonation of the explosive charges and can be selected in accordance with other considerations, for instance it can be a material having good adhesion for carbon powder or other material used for the opaquingcharge, such as the material available under the tradename Ziellon. This is also a reason why the shutter according to the present invention can be made of much lighter weight and of much smaller thickness than would otherwise be possible, considerations which are evidently also important. The fact that the frame can yield makes it also charges, that is the wires which are to connect the charges with a source of electrical energy for detonating them, in the frame itself. In fact, a plug or connector may also be embedded, with the wires connected to it and with suitable male or female portions of the connector being exposed at the exterior of the frame for engagement with a similar external connector which in turn is in electrically conductive relationship with a source of electrical energy. By so embedding the wires and the connector, considerable labor is saved which would otherwise be necessary for installing these components in proper manner. Also, the charge of carbon powder and the explosive charge (or charges, if more than one are provided of each) are embedded in the frame so as to be sealed with respect to the outer side thereof, which eliminates the necessity for providing screw connectors as in the prior art into which these components are threaded from the exterior.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a cross section through an embodiment according to the present invention;

FIG. 2 is a diagrammatic plan view through a further embodiment of the invention;

FIG. 3 is a section taken on line III-III of FIG. 2; and

FIG. 4 is a fragmentary section through still another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing now in detail, and firstly the embodiment illustrated in FIG. 1, it will be seen that the shutter disclosed in the Figure is provided with two spaced, parallel transparent outer plates 1. These plates 1 may be of synthetic plastic material or of glass, depending upon the requirements made of the, especially optical requirements. If synthetic plastic material is utilized, it may advantageous be polymethylmethacrylate of the type which is commercially available under the tradename Plexiglass," or polycarbonate of the type available under the tradename Makrolon." Located between the plates 1, in parallelism therewith and spaced from both of them, is an inner or intermediate plate 3, which may be of a material having particularly good adhesive characteristics (to facilitate adhering of the carbon powder or the like to it), or which may have other desirable characteristics, for instance it may be of a material which is especially resistant to thermal energy. Such material may for instance be of the type which is commercially available under the tradename Cellon" from the German "Dynamit" Company. Of course, the plate 3 must be transparent as are the plates 1.

A frame 6 is provided, in this instance composed of elastomeric material which is resiliently yieldable, and silicon rubber with high resilience is particularly advantageous for this purpose. The plates extend across the opening provided in this frame 6, and in the region of the outer circumferential margin of the plate 3 there are embedded in the frame 6 charges 3 of carbon powder in which in turn there are embedded explosive charges 4 of known type. Reference numeral 5 designates conductors which are connected with the charges 4, also being embedded and extending to the exterior of the frame 6 for connection with a source of electrical energy which is required to detonate the charges 4.

Frame 6 is surrounded at its outer side with a member 7 which is of substantially U-shaped cross section with the open side facing inwardly towards the frame 6. Member 7 may be of synthetic plastic material or of metal and is utilized particularly for relatively largedimensioned shutters, especially if they have a rectangular or quadratic outline. If the member 7 is of metallic material, it can be conductively connected with one of the wires 5 whereas the other wire passes out of the frame 6 and out of the member 7 via an insulated bushing 9 to provide an external contact 8 for connection with a source of electrical energy. 7

It will be appreciated that in place of the charges illustrated in FIG. 1, others can be utilized. For instance, it is possible to provide that chamber which faces towards the light source that is the nuclear flashwith an explosive wire which, when electrically detonated, will explosively vaporize so that its vaporized particles become deposited on the plate surfaces binding the chamber in question. The other chamber, that is the one facing away form the light source, can be provided with the carbon and explosive charges described with respect to FIG. 1. This embodiment is insofar advantageous as the vaporized particles of the explosive wire provide excellent reflective capability in the chamber facing towards the explosion (that is the nuclear explosion), whereas carbon powder is preferred for the other chamber because it provides for a more definite blackening.

Coming to the embodiment in FIGS. '2 and 3 it will be seen that here there is illustrated a smaller shutter of circular outline. In such smaller shutters, and particularly in shutters of circular outline, the member7 of the embodiment in FIG. 1 may be omitted. This is especially true when the outer transparent plates 11 and the intermediate plate 12 are secured together by means of bolts or screws 19 which are distributed about the circumference of the shutter. The frame 16 is again of elastomeric material of high yielding capability, and it is possible but not necessary to locate intermediate the plate 12 and the two plates 11 a spacing member or spacing rings in order to locate and maintain the plates in parallel relationship.

FIGS. 2 and 3 show that a single carbon charge and explosive unit is located at the frame centrally intermediate the plates 11, so that it can discharge to both axial sides of the plate 12. Thus, the central unit discharges into both of the chambers simultaneously and opaques both chambers simultaneously. The explosive charge 14 is located again in the carbon powder charge 13 and electrically conductive wires 15 are provided which extend to the outer side of the frame 16. Of course, a single unit can be utilized only if the cross section which is to be blackened is not so large that excessive time will be required for effecting the opaquing. Alternately more than one such unit can be provided, distributed about the circumference of the shutter.

In the embodiment of FIG. 4 we show that a shutter according to FIG. I can be constructed in accordance with the opaquing concept of FIGS. 2 and 3. In other words, the single unit (or each unit) can act on both chambers simultaneously to opaque them. In this embodiment the carbon powder charge 24 has embedded in it the explosive charge 25, being so located in a frame 26 intermediate the two outer plates 21 that the two chambers, which are defined between the plates 21 by the intermediate plate 22, will both receive carbon powder simultaneously from the charge 24.

Shutters of the type here in question frequently must be capable of storage for prolonged periods of time. In order to prevent the intrusion of moisture into the carbon powder charge under such circumstances, it is possible to provide on the carbon powder charge a cover, preferably in the form of a coating of colonium or Zapon lacquer and to thereby seal the charge against the intrusion of moisture. In addition, such a coating prevents falling-out of carbon particles into the chambers, for instance in case of an impact on the shutter during careless handling or the like.

In addition, the intrusion of air and moisture can also be visually signalled according to a concept of the invention, in that the two chambers are evacuated to an extent sufficient to cause the outer plate to become slightly inwardly deformed in a concave manner. This is true particularly in the shutters having plates or synthetic plastic material and as long as the concavity is visible the user is assured that air and moisture will not have intruded. On the other hand, if the concavity is not visible, then the shutter is replaced as no longer absolutely reliable in its operation.

The assembly of the shutter may be carried out in a manner analogous to that disclosed in German Pat. No. 1,939,740.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in anti-flash shutter, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended:

1. An anti-flash shutter, comprising a frame having an opening for the passage of light; first means extending across said opening and defining a chamber; second means also extending across said opening and subdividing said chamber into one compartment adapted to face the heat flash of a nuclear explosion and subject to destruction by such flash, and an axially successive additional compartment through which light must pass after passing through said one compartment; and third means for simultaneously terminating the passage of light through both of said compartments so that maximum opaquing of the shutter results upon the occurrence of a flash and opaquing of at least said additional compartment remains even in the event of destruction of said one compartment.

2. An anti-flash shutter as defined in claim 1, said center plate having a circumferential margin; and wherein said third means is located in the region of said margin.

3. An anti-flash shutter as defined in claim I, said first means comprising at least two at least substantially parallel transparent outer plates spaced from one another so as to form said chamber, and said second means comprising a center plate located between said outer plates.

4. An anti-flash shutter as defined in claim I, wherein said third means comprises at least one unit including a charge of carbon powder and an explosive adapted to discharge said carbon powder into one of said compartments, and at least one explosively vaporizable wire adapted to discharge into the other of said compartments and form a reflective layer therein.

5. An anti-flash shutter as defined in claim 3, said center plate being of a material having high thermal resistance.

6. An anti-flash shutter as defined in claim 3, said plates having circumferential margins sealingly connected with said frame; and wherein said frame is composed at least predominantly of elastomeric material which is resiliently yieldable.

7. An anti-flash shutter as defined in claim 6, wherein said elastomeric material is silicone rubber.

8. An anti-flash shutter as defined in claim 6, further comprising an electrically conductive additive admixed with said elastomeric material.

9. An anti-flash shutter as defined in claim 8, wherein said additive is graphite.

10. An anti-flash shutter as defined in claim 3, wherein said plates are of synthetic plastic material.

11. An anti-flash shutter as defined in claim 3, said. third means being electrically activatable; and further comprising electrical conductor means and connecting plug means embedded in said frame.

12. An anti-flash shutter as defined in claim 3, said plates having circumferential margins, and said frame being profiled and sealingly engaging said margins.

13. An anti-flash shutter as defined in claim 3, said plates having circumferential margins connected with said frame; and further comprising an annular inwardly open member of U-shaped cross-section exteriorly embracing said frame and margins and maintaining the latter in tight engagement with the former.

14. An anti-flash shutter as defined in claim 13, said member being of metallic material.

15. An anti-flash shutter as defined in claim 13, said member being of synthetic plastic material.

16. An anti-flash shutter as defined in claim 13, said member being of glass-fiber reinforced synthetic plastic material.

7 8 17. An anti-flash shutter as defined in claim 13; and 19. An anti-flash shutter as defined in claim 3; further further comprising a strap overlying a radial edge face comprising spacing members interposed between said of said annular member in taut condition. center plate and the respective outer plates.

18. An antiflash shutter as defined in claim 3, 20. An anti-flash shutter as defined in claim 3, wherein said compartments are partially evacuated to wherein at least one of said plates is a filter for laser an extent requisite for causing concave inward deforbeams.

mation of said outer plates.

Claims

3. An anti-flash shutter as defined in claim 1, said first means comprising at least two at least substantially parallel transparent outer plates spaced from one another so as to form said chamber, and said second means comprising a center plate located between said outer plates.

4. An anti-flash shutter as defined in claim 1, wherein said third means comprises at least one unit including a charge of carbon powder and an explosive adapted to discharge said carbon powder into one of said compartments, and at least one explosively vaporizable wire adapted to discharge into the other of said compartments and form a reflective layer therein.

11. An anti-flash shutter as defined in claim 3, said third means being electrically activatable; and further comprising electrical conductor means and connecting plug means embedded in said frame.

17. An anti-flash shutter as defined in claim 13; and further comprising a strap overlying a radial edge face of said annular member in taut condition.

18. An anti-flash shutter as defined in claim 3, wherein said compartments are partially evacuated to an extent requisite for causing concave inward deformation of said outer plates.

19. An anti-flash shutter as defined in claim 3; further comprising spacing members interposed between said center plate and the respective outer plates.

20. An anti-flash shutter as defined in claim 3, wherein at least one of said plates is a filter for laser beams.