US2588424A

US2588424A - Electric switch

Info

Publication number: US2588424A
Application number: US121045A
Authority: US
Inventors: Harry B Speaker
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1949-10-12
Filing date: 1949-10-12
Publication date: 1952-03-11
Anticipated expiration: 1969-03-11

Description

March 11, 1952 H. B. SPEAKER ELECTRIC SWITCH Filed Oct. 12, 1949 FIG.|

FIG. 2

FIG.4

IN V EN TOR.

HARRY B. SPEAKER ATTORNEY Patented Mar. 11, 1952 UNITED STATE S PATENT O FF ICE ELECTRIC SWITCH Harry B. Speaker, Neptune, N. J assignor to the United States of America as represented by the :Secretary of the Army Application October 12, 1949, Serial No. 121,045

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 6 Claims.

closed by subjecting the switch to acceleration- 101 .3 P riod of time. Although said switch is :Darticu'arly "useful in an ordnance projectile, or the like, '10). the purpose of closing an electric :circuitiordetonating its war head, its usefulness is not limited thereto.

{Bhepresent invention is made up of two chambers which intercommunicate through a conduit pierced :by a restricted delay channel. Said chambersand channel contain a mobile electrical conductor (such as mercury). Each chamber also contains a gas (such as .air) which is more 'rarifiedin one chamber ("lower pressure chamber) than in the other (higher pressure chamber). .-As a result of this pressure differential, whfin the switch ,is unoperated (at rest), said mobile conductor is maintained in a condition of balance, at diiierent levels or heights in the two chambers. For convenience I will refer to these levels in the two chambers as unoperated levels.

When the device is subjected to acceleration, said mobile conductor flows from the lower pressure chamber to the h gher pressure chamber, until a new condition of balance is effected, with said .mobile conductor atother levels in the two chambers (which I will refer to as operated levels). This flow reouires a certain length of time. which is a function of the viscosity of the mobile conductor, the pressure differential. the relative heights .of the mobile conductor in the two chambers, the cross-sectional size of the delay channel and the degree of acceleration applied.

:One or more electrical terminals are suitably posit oned in one or both chambers so as to be in electrical contact with the mobile conductor, either in its unoperated condition (at rest) or in its operated condition (after the application of acceleration for a requisite period of time). If, in the unoperated condition, said mobile conductor is in contact with a terminal, then a circuit incorporating said .terminal may be opened upon the application of a predetermined amount of acceleration. If, however, in the unoperated condition, the mobile conductor is not in contact with a terminal. then the closing ofa circuit may ,be accomplished by acceleration.

An object of the present invention is to provide an electrical switch operated by acceleration and, moreparticularly, to provide such a switch having a time delay.

Another object is .to provide such an acceleration actuated switch, wherein a circuit may be either opened or closed.

Still another object is to provide such a switch which returns to its at rest, or unoperated, condition after acceleration has ceased and, particularly, which returns .to its said unoperated condiv tion without having efiected any circuit change, in the event that an insufficient amount of acceleration-has been applied.

Yet another object is to provide such a switch which may be relatively small in size, simple, inexpensive and completely enclosed, and which need have no moving structural parts.

In the drawings, which are .drawn to an enlarged scale:

Figure 1 is .a vertical cross section of one embodiment of the present invention in an at rest or unoperated condition,

Figure 2 shows the embodiment of Figure 1 in its operated condition (after having been subjected to a requisite amount of acceleration),

Figure 3 is a vertical cross section of a second embodiment of the present invention in its at rest or unoperated condition; and

Figure 4 similarly shows said second embodiment when sufiicient acceleration has been applied to operate it.

Referring now to Figures 1 and 2, the first embodiment of the present invention there illustrated comprises cy-indrical lower pressure and higher pressure chambers II, I3 which intercommunicate by Way of a conduit or tube I5 pierced by a relatively restricted delay channel I6. The walls of said chambers II, I3 and tube I5 may be of any suitable dielectric material (such as glass or plastic) which has suflicient structural strength to take the strains of operation of the device.

The chambers II, I3 are partially filled with mercury IT, or some other suitable mobile electrical conductor which may flow through the delay channel I6. When in its unoperated condition (i. e. when it is at rest), there is a higher head or level of mercury I1 in the lower pressure chamber I I than in the higher pressure chamber I3, because a suitable gas l8 (as air) in the space above the mercury in the chamber II has been rarified to a greater degree than a gas 20 in the chamber I3.

' The lower pressure chamber I I is provided with i two electrical terminals I9 which extend through pressure chamber I3.

the walls of said chamber and are suitably hermetically bonded to said walls. The higher pressure chamber I3 is likewise provided with a pair of electrical terminals 2|. It will be noted that the terminals I9 are located below the unoperated level of the mercury I! in chamber II (as shown in Figure 1), but above the operated level of the mercury in said chamber II (as shown in Figure 2). Similarly the terminas 2| in the higher pressure chamber I3 are located intermediate the unoperated and operated levels (shown respectively in Figures 1 and 2) of the mercury I! in said chamber I3.

Re erring now to Figures 3 and 4 of the draw-' ing, the second form of my invention there illus- Fach of the

chambers

25, 21 is partially filled with mercur 33, or some other suitable mobile conductor whi h may flow through the delay channel 32. The lower end of t e tube 3I' extends down far enough sothat it is always submer ed in the mercury 33 at any operating level I of the mercury in the hi her pressure chamber 21. The gas 3 above the mercury 33 in the lower pressu e chamber 25 has a lower pressure than t e gas 3'! in the hi her pressure chamber 21, With t e re ult that, when unoperated, there is a relativel hi h level of mercury 33 in said chamber 25 and a relatively low level of mercury in said chamber 21.

Extending through the side walls of the lower pres ure chamber 25 and hermetically sea ed the ein are a pair of electrical te minals 39. The hi her pressure chamber 27 is similarly provided with a pair of electrical terminals 4|. Said terminals 39 are positioned intermediate the unoperated and operated levels (shown respectively in Figures 3 and i) of mercury 33 in the chamber 25, and. similarly, the terminals 4! are located at a position which is intermediate the unoperate and operated levels of mercury in the chamber 21.

Although not shown in the drawing because not necessarily a part of the present invention, a device embodying the present invention would, in some applications, be mounted in gimbals so as to maintain the device level at all times.

In the operation of the form of my device illustrated in Figures 1 and 2, the elements are as shown in Figure 1 when the device is at rest (unoperated). Due to the differential pressure of the gases I8, 20 in the chambers II, I3, the mercury I I achieves a state of balance at the unoperated levels shown in Figure 1. As there shown, the level of the mercury I! is higher in the lower pressure chamber I I than in the higher The terminals I9 and/or 2! may be connected into any suitable circuit or circuits (not shown). As, when unoperated, the terminals I9 are submerged in the mercury I I, any circuit connected thereto is closed at said terminals. However, as the terminals 2| are then above the unoperated level of the mercury I'E in the higher pressure chamber I3, any circuit connected through said terminals is open.

During operation, the device is subjected to an acceleration. When this occurs, mercury I] ZfiQWS small size of the delay channel I6 as compared n v.) v)

to the viscosity of the mercury I'I, this flow will continue for a finite period of time until a new state of balance is reached (Figure 2). It will be seen, that the terminals I9 are now above the operated level of the mercury H in the lower pressure chamber I I so that any circuit in which they are connected will have been opened. Also, the terminals ZI are now submerged in the mercury I I in the higher pressure chamber I3 so that any circuit in which they are connected will have been closed. As soon as the acceleration ceases, the differential pressure or" the gases I8, 20 will cause the mercury I! to flow back to the unoperated levels (Figure 1).

It will be understood that a certain combination of acceleration and time are necessary before the mercury I'I reaches the operated levels (Figure 2) so as to efiect electrical disconnection of the terminals is and connection of the terminals 2I. advance, and the sizes of the chambers I I, I3, the cross sectional area of the delay channel I6, the amount of mercury Il, the relative pressures of the gases i8, 28, the relative positions of the terminals 9, 2i and other factors may be chosen to meet any desi ed operating characteristics. The basic principle of operation, however, will remain the same.

Although two sets of terminals I9, 2I have been shown. it will be understood thatthis is merely illustrative and 'a particular embodiment may have only one of the sets or, if two sets are 'pro-' vided, only one may be" used. Also one terminal of each set i9, 2! may be at a lower level so as to" be submerged in the mercury ll during all stages of operation. Again, a plurality of terminals may be used so as to achieve any desired sequential operation. Thus, for instance, several sets of terminals (not shown) may be disposed at different levels so as to open or close circuits at differenttime intervals.

The operation of the second embodiment (Figures 3 and 4) is similar to the operation already described, the lower pressure and hi her pressure chambers 25, Z'I being similar to the chambers II and I3, respectively, of Figures 1 and 2. This second embodiment may be considered more satisfactory for some installations, because of its compactness and unitary form, and it also has the advantage of having the conduit 3! disposed entirely within the cylindrical structure so as to be less subject to damage.

The present invention may be used irrespective of the direction in which the acceleration is applied. Thus, in a projectile which should reach a certain altitude before its war head is triggered, the acceleration acts in a vertical direction. But in a centrifugal machine, the acceleration may be applied horizontally or, as a matter of fact, in any direction. The heights of the mobile conductor are then efiective along the axis of acceleration. Thus, in the present patent application, such terms as unoperated level, operated" level, etc., are to be considered relative to a particular axis of acceleration, which may or may not be vertically oriented.

While there have been described what are at present considered to be preferred embodiments of my invention, it will be obvious to those skilled in the art that changes and modifications may be made therein without departing from the invention and it is aimed in the appended claims to Obviously this may be calculated in cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. An acceleration operated electric switch comprising, a closed lower pressure chamber, a closed higher pressure chamber, a conduit provided with a delay channel interconnecting said chambers, a mobile electrical conductor within said chambers and channel, gas in each of said chambers, the gas in said lower pressure chamber being more rarified than the gas in said higher pressure chamber, said mobile conductor extending, in one of said chambers, to unoperated and operated levels when said switch is in unoperated and operated conditions respectively, at least one electrical terminal in said last-mentioned chamber at a position intermediate said unoperated and operated levels, so that, when said mobile conductor is at one of said levels, it is in electrical contact with said terminal and, when it is at the other of said levels, it is electrically disconnected from said terminal.

2. A switch as defined in claim 1, wherein said chambers are juxtaposed laterally relative to the axis of acceleration.

3. A switch as defined in claim 1, wherein said chambers are arranged in tandem along the axis of acceleration.

4. An acceleration operated electric switch comprising two closed chambers, a conduit provided with a delay channel interconnecting said chambers, a mobile conductor in said channel and chambers, a gas in each chamber, said gas in one chamber being more rarified than said gas in the other, said conductor extending to unoperated and operated levels in each of said chambers, an electrical terminal in one of said chambers positioned intermediate the unoperated and operated levels in said chamber.

5. An acceleration operated electric switch comprising, a closed lower pressure chamber, a closed higher pressure chamber, a conduit provided with a delay channel interconnecting said chambers, a mobile electrical conductor within said chambers and channel, gas in each of said chambers,

the gas in said lower pressure chamber being more rarified than the gas in said higher pressure chamber, said mobile conductor extending, in said lower pressure chamber, to an unoperated level when said switch is in an unoperated condition and to an operated level, which is lower, when said switch is in an operated condition, at least one electrical terminal in said lower pressure chamber at a position intermediate said unoperated and operated levels, so that, when said mobile conductor is at said unoperated level, it is in electrical contact with said terminal and, when said mobile conductor is at said operated level, it is electrically disconnected from said terminal.

6. An acceleration operated electric switch comprising, a closed lower pressure chamber, a closed higher pressure chamber, a conduit provided with a delay channel interconnecting said chambers, a mobile electrical conductor within said chambers and channel, gas in each of said chambers, the gas in said lower pressure chamber being more rarified than the gas in said higher pressure chamber, said mobile conductor extending, in said higher pressure chamber, to an unoperated level when said switch is in an unoperated condition and to an operated level, which is higher, when said switch is in an operated condition, at least one electrical terminal in said higher pressure chamber at a position intermediate said unoperated and operated levels, so that, when said mobile conductor is at said unoperated level, it is electrically disconnected from said terminal and, when said mobile conductor is at its operated level, it is in electrical contact with said terminal.

HARRY B. SPEAKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,600,121 Mazade Sept. 14. 1926 1,695,546 Goodhue Dec. 18, 1928 2,236,790 Erich Apr. 1, 1941 2,404,179 King July 16, 1946