US2961502A

US2961502A - Switch devices

Info

Publication number: US2961502A
Application number: US569521A
Authority: US
Inventors: Frank A Hester
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-11-18
Filing date: 1944-12-23
Publication date: 1960-11-22
Anticipated expiration: 1977-11-22

Description

NOV. 22, 1960 TER 2,961,502

SWITCH DEVICES Original Filed Nov. 18, 194s IN V EN TOR.

F RFINK H. HESTER BY 68 [A rme/vr/ SWITCH DEVICES Frank A. Hester, New York, N.Y., assignor, by mesne assignments, to the United States of America as. represented by the Secretaryof the Navy Original application Nov. 18, 1943, Ser. No. 510,798. Divided and this application Dec. 23, 1944, Ser. No. 569,521

8 Claims. (Cl. ZOO-61.01)

This invention relates to switch devices, and. more particularly to an electric switch for opening and closing.

closed andclaimed in my above identified copending application. Under certain circumstances, it is desirable to avoid firing of the charge, and the primary object of my present invention is to provide an improved electric switch for use in a depth charge firing control circuit which will accomplish this purpose.

More part cularly, it is an object of my present invention to provide an electric switch of the inertia type which is responsive to mechanical vibrations, such as acoustical waves or the like, for controlling an electric circuit in which it may be connected.

Another object of my present invention is to provide an improved electric switch as aforesaid which can be made very sensitive.

Still another object of my present invention is to provide an improved inertia type, electric circuit controlling switch which will serve to instantaneously open or close a circuit upon predetermined movement of a vibratory member thereof.

A further obiect of my present invention is to provide an inertia type. electric circuit control switch as above set forth which is particularly useful in a depth charge detonating control circuit for controlling the firing of the charge.

It is also an ob ect of my present invention to provide an inertia type, electric circuit controlling switch as above set forth which is very s mple in construction, inexpensive in cost. and highly efiicient in use.

In accordance with my present invention, I provide a pair of vibratory spring members, preferably but not necessarilv of the leaf spring type, one of which is relatively stiff and the other of which is relative y flexible. One end of the stiff spring is secured to a suitable support and its other end is freely suspended. Secured to the stiff spring, in proximity to its freely suspended end, is a weight or mass which is tuned with this spring to some suitable, predetermined frequency; or flexible spring has one end secured to the aforesaid weight or mass and its other end is also freely suspended for cooperation with a contact member which may be carried by the aforementioned weight or may be secured to some other suitable member in spaced relation to the freely suspended, vibratory end of the more flexible spring. The latter spring is tuned, either by itself or with a suitably added mass or weight, to substan tially the same frequency as that to which the stifi Spring and its associated mass are tuned. The relative The second fiexibilities of the two springs are such that,- when the stiif spring is. set into. vibration by an external force to vibrate with some particular amplitude at substantial- 1y its resonant frequency, the second or flexible spring will be causedv to vibrate thereby at substantially the same frequency but with much greater amplitude. Upon vibration of the latter spring, which constitutes one contact element of the switch, it will engage the othercontact element of the switch to thereby complete the electric circuit in which it is connected. The last mentioned contact element may be made adjustable relative to the flexible spring so that the circuit will not be closed until the vibration of the flexible spring has reached a certain, desired amplitude. In this way, the switch may be made extremely sensitive.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, as well as additional objects and advantages thereof, will best be understood from the following description of one embodiment thereof, when read in connection with the accompanying drawingin which the single figure shows a central, sectional view of a switch constructed in accordance with my present invention and connected in the control circuit of a depth charge firing device.

Referring more particularly to the drawing, there is shown a depth charge detonating control device 1 comprising a diaphragm of magnetic material having a vibratory, central portion 5 coupled to the outer, annular portion thereof by a thin, flexible, annular portion 7 whereby the central portion 5 is capable of acting substantially as a piston. A magnetostriotive rod or the like 9 is secured to the vibratory portion 5 of the diaphragm and forms therewith a vibratory system. The rod 9 has two motional nodes around one of which is placed a winding 11 which constitutes a driving coil for the vibratory diaphragm portion 5, and around the other of which is a winding 13 constituting a driven coil. The driving coil or winding 11 is connected in the output or pate circuit of a power amplifier 15 (eg, a type 3A4 tube), and the driven coil 13 is connected in the input or grid circuit of a combined detector and amplifier 17 (e.g., a type 1T4 tube). The vibratory diaphragm portion 5, the magnetostrictive rod 9, the two

windings

11 and 13, and the tubes 15 and 17 form an oscillating circuit which generates the outgoing signal. The output of the detector-amplifier i7 is connected to the power amplifier l5 and excites the power ampifier 15 which then drives the rod 9 through its output coil 11, while the rod 9, in turn, excites the detector-amplifier tube 17 through the receiving coil 13. This oscillatory system is arranged to oscillate preferably at the natural frequency of the vibratory system comprised of the diaphragm portion 5 and the rod 9, and this frequency may be approximately 25 kc. per second. The length of the rod 9 is preferably equal to three-fourths of the wave length at the natural frequency of the oscillating. system, and, as stated above, the

windings

11 and 13 are preferably arranged about the rod 9 at the two motional nodes thereof.

An oscillatory system as above described may be connected to a depth charge in the manner more fully disclosed in my above identified copending application and makes use of the Doppler effect to obtain firing of the charge at the point of closest approach to the target. As the depth charge falls, the unit emits, continuously, a high frequency acoustic signal which is reflected from the target back to the diaphragm 3.. Due to the fact that a relative velocity exists between the depth charge -and;the

target, the received, reflected signal and the outgoing,

transmitted signal and on the magnitude of the relative velocity between the charge and the target. The weak, reflected signal is'received by the vibratory-portion 50f the diaphragm and sets into vibration the magnetostrictive rod 9. This energizes the driven coil 13, and the signal is amplified by regeneration around the oscillator loop. Due to this regeneration, the amplitude of the signal is suflicient to produce a heterodyne at the grid of the detector-amplifier 17. Thus, a component of which the frequency is the difference between the outgoing signal and the reflected signal appears in the output of the detectoramplifier 17, since this tube acts as a simple, grid-leak detector. The circuit is so designed that the detectoramplifier 17 operates at maximum detector sensitivity, while the power amplifier 15 operates at maximum power output.

' The output of the amplifier 17 is connected to a multistage, selective amplifier 19 which responds only to very low frequencies. When the frequency difference is in the order of about 30 cycles per second (or anyother suit able, low frequency), this signal is passed by the amplifier 19 and is applied to a limiter amplifier 21. The characteristic of this circuit, as more particularly described in my above identified copending application, is such that it will not respond at all to weak signals, while its response to strongsignals is independent of the signal strength.

The output of the limiter amplifier 21 is coupled to a normally-blocked, cold-cathode discharge device 23 (e.g., a type 359A tube), which acts as a firing tube. A capacitor 25 is connected in series with the tube 23, as is also a detonator 27 of a suitable depth charge. The capacitor 25 is normally charged through a resistor 29 from a suitable DC voltage source connected at the point A. When a strong signal is applied to the limiter amplifier 21 for predetermined time (e.g., one-fifth second). it will effect firing of the tube 23. When the tube 23 is fired, it provides a current discharge path therethrough for the capacitor 25 and the detonator 27 whereby firing of the charge is effected.

Under certain circumstances, it is desirable to prevent firing of the charge as, for example, in response to certain extraneous noises such as those produced by the explosion of another charge in the vicinity of the controlled charge. For this purpose, I provide a switch 31 constructed in accordance with my present invention and adapted to act as an anti-countermine switch. The switch 31 includes a relatively stiff leaf spring 33 which is connected at one end to the diaphragm 3 or to some other suitable member rigidly connected with the diaphragm, the opposite end of the spring 33 being freely suspended.

37 and 39 remain spaced from each other. Any abnormally intense, undesirable acoustical waves having cornponent frequencies of the order of the resonant frequency of the switch 31 which strike the diaphragm 3 will cause the spring 33 and the mass 35 to vibrate at the resonant frequency thereof. This, in turn, will cause the spring 37 to vibrate at substantially this resonant frequency, but with much greater amplitude, to contact the screw 39 and thereby complete a circuit through a resistor 45 connected to the capacitor 25 in shunt relation with the discharge tube 23 and the detonator 27. Thus, when an abnormally intense wave strikes the diaphragm 3, the circuit I through the resistor 45 is completed before the one through the discharge tube 23 is completed and the capacitor 25 discharges through the resistor 45 instead of through the detonator 27. In this way, prematurefiring of the depth charge is avoided. If the source of the abnormally intense waves or undesired vibrations should be at a considerable distance. fro-m the controlled depth charge, the amplitude of the abnormal vibrations striking the diaphragm 3 may be very small. It is for this reason that the switch 31 is arranged as above described so as to greatly multiply the amplitude of vibrations in the spring 37 due to the relative flexibility of the springs 33 and 37 and thereby insure engagement of the spring 37 with the terminal screw 39 to complete the alternative current discharge path through the resistor 45 for the capacitor 25. By making the screw 39 adjustable on the terminal plate 41, the spacing between the contact elements 37 and 39 can be varied to require a greater or lesser amplitude of vibration of the spring 37 before it will contact the screw 39. In this way, the sensitivity of the switch 31 can be readily controlled.

Although I have shown and described but a single form of my present invention, it will undoubtedly be apparent to those skilled in the art that many other modifications thereof, as well as changes in the particular one described, are possible. For example, instead of employing leaf springs, other suitable vibratory members To the latter end of the spring 33 is connected a weight n is in connection with safes.

may be used, or other forms of springs may be used, if desired. Also, while I have described my present invention with particular reference to a firing control circuit of a depth charge, it should be apparent to those skilled in the art that many other uses thereof are possible. For example, the switch of my present invention may be employed in a control circuit for a vibratory system which is not to exceed a certain degree of vibration. In

such case, the switch will close when the spring 37 has attained a predetermined amplitude of vibration to thereby control the vibrating force in any suitable manner. Another possible use of the switch of my present invention The switch may, for example, be mounted in some suitable location within the safe and set into vibration when an unauthorized person readily suggest themselves.

vide the desired tuning. The diaphragm 3 may be grounded and the spring 33, the mass 35, and the spring 37 are conductively connected thereto. As clearly shown in the drawing, the spring 37 also has one end freely suspended and arranged to serve as one contact element of the switch for cooperation with a second contact element 39. The contact element 39 may comprise an adjustable screw carried by a terminal plate 41 which may be mounted either on the mass 35 through an insulating block 43 or on some other, suitable member which is insulated from the contact spring 37.

Upon normal operation of the firing circuit as described above, the switch 31 is inactive and the contact elements tampers with the safe, as by tapping, whereupon the switch will be operated to close an alarm circuit or the like. Many other uses and applications will, no doubt, I therefore desire that my invention shall not be limited except insofar as is made necessary by the prior art and by the spirit of the appended claims.

I claim 'as my invention:

1. An inertia switch device comprising a first vibra-' tory member, a second vibratory member carried by said first vibratory member and constituting one contact element of said switch, and a second contact element cooperatively associated with said second vibratory memher in spaced relation thereto, said vibratory members being so related to each other that upon vibration of said first vibratory member with relatively small amplitude, said second vibratory member will be caused to vibrate thereby with relatively large amplitude and will engage said second contact element for closing said switch.

2. An inertia switch device comprising a first vibra;

tory member tuned to a predetermined frequency, a second vibratory member carried by said first named vibratory member and constituting one contact element of said switch, said second vibratory member being tuned to substantially the same frequency as said first vibratory member, and a second contact element cooperatively associated with said second vibratory member in spaced relation thereto, said vibratory members being so related to each other that upon vibration of said first vibratory member at said frequency with relatively small amplitude, said second vibratory member will be caused to vibrate thereby at substantially said frequency with relatively large amplitude and will engage said second contact element for closing said switch.

3. An inertia switch device comprising a first spring member, a mass associated therewith and tuned with said spring member to a predetermined frequency, a second spring member resiliently carried by said mass and constituting one contact element of said switch, and a second contact element cooperatively associated with said second spring member in spaced relation thereto, said spring members being so related to each other that upon vibration of said first spring member at said frequency with relatively small amplitude, said second spring member will be caused to vibrate thereby at substantially said frequency with relatively large amplitude and will engage said second contact element for closing said switch.

4. An inertia switch device comprising a first spring member, a mass associated therewith and tuned with said spring member to a predetermined frequency, a second spring member resiliently carried by said mass and constituting one contact element of said switch, and means also carried by said mass constituting a second contact element of said switch, said second spring member being so related to said mass and said first spring member that upon vibration of said first spring member and said mass at said frequency with relatively small amplitude, said second spring member will be caused to vibrate thereby at substantially said frequency with relatively large amplitude and will engage said second contact element for closing said switch.

5. An inertia switch device comprising a first and relatively stiff spring member, a mass associated therewith and tuned with said spring member to a predetermined frequency, a second and relatively flexible spring member resiliently carried by said mass and constituting one contact element of said switch, and means also carried by said mass constituting a second contact element of said switch, said second spring member being so related to said mass and said first spring member that upon vibration of said first spring member at said frequency with relatively small amplitude, said second spring member will be caused to vibrate at said frequency with relatively large amplitude and will engage said second contact element for closing said switch.

6. An inertia switch device according to claim 3 Wherein the mass and resilience of said second spring member are such that second spring member is also resonant at substantially said predetermined frequency.

7. An inertia switch device comprising a first and relatively stiff leaf spring fixed at one end and freely suspended at its other end, a mass carried by said spring in proximity to its said free end, said mass and spring being tuned to a predetermined frequency, a second and relatively flexible leaf spring having one end fixedly connected to said mass and its other end freely suspended relative to said mass, said second spring being also tuned to substantially said predetermined frequency and its freely suspended end constituting one contact element of said switch, and a second switch contact element carried by said mass in association with the freely suspended end of said second leaf spring, said leaf springs being so related that upon vibration of said first spring with relatively small amplitude at said frequency, said second spring will be caused to vibrate thereby at substantially said frequency with greater amplitude whereby its freely suspended end will be brought into engagement with said second contact member for closing said switch.

8. An inertia switch device according to claim 7 wherein said second switch contact element is adjustably carried by said mass for adjustment relative to said second leaf spring.

No references cited.