US2420028A

US2420028A - Electrical switch

Info

Publication number: US2420028A
Application number: US438506A
Authority: US
Inventors: Robert M Bleakney; Everly J Workman
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-04-10
Filing date: 1942-04-10
Publication date: 1947-05-06
Anticipated expiration: 1964-05-06

Description

May 6, 1947- R. M. BLEAKNEY ET A1. `2,420,028

ELECTRICAL SWITCH Filed April 10, 1942 WW/1' A A A A l A A l A' A A A A j...

ATTORNEY Patented May 6, 1947 .T ENT 0. FF If Albuquerque,

.. Mex., assignorsv to theUnitcd` Stoicsof AmericaV as rcorosintesir b v` the Score! .tary of the. New

Application April 10, 1942, Seralfllo. .438,5i6'` Zlaims- 1 'Iglnsfinvention relates to electric switches, and. in: particular, to an improved switch of` the so called inertia type, in which the circuit Contact; members .thereof are .operated as,` switch ,body is subieotedto acceleration @ne application oifour invention is-tofanprdie nance projectile within wirlich` the` switch may be installed? fory the purpose of4 closing an elec-H tric circuit-for detonating a powdery charge with?. inthe projectile asethe Vlatter isaccele-ated upon` being medi-rom, a gun. it will be. understood, however, that: o-u-r improved switch may bel uti;-V lized'fonotherapplications.andthat the appended claims-.shouid'be so construed.`

An` object; of our invention 4is to. provide an improvedL typeot: inertia. switch in which the switch` contaos: will be closed` and locked, inf their l closed: position as` the switch is; subjected to ac. celeration.

Another object of; our. invention is. to provide.

an inertia.ty1pe.switch in` which an incr-tia. contanti memberisrinitially-spaced from a` iixed con?. tact member. byv an extensible tie member, the. latter member being extended as. the switci-i` is.` subjectedto, aV predetermined' degree. of: accelera?,` tion, permitting the, lined.` and inertia contact members to l move towards. and .engage each other.

Another object is to provide aninertia oper.- ated switchiawhichwthe-inertia contact member is initially spaced apart from the xed contact member by a t i`e.member. of ductile material, which, when the switch is subjected to a predetermineddegree` of acceleration will elongate to permit the inertia Contact member to engage the xed contactmembee of the switch.

A further object is to provide an inertia operated switch in which an inertia contact member is-` in-itiallzgrl spaced apa-rt from the fixed contact member by a Closely coiled. tie member which Will be elongated as the switch ismsubjected to a pref determined degree of elongationgpermitting:the switch contact members to engage each other...

Sti1l-another object ofour invention is to provide an inertia switch in which the inertia contact member is initially spaced apart from the iixed contact member by a closely coiled tie mem ber of ductile material, the latter being permanently elongated as the switch is subjected to an acceleration, thereby permitting the fixed and inertia contact members to engage each other.

Another object is to provide an inertia operated switch utilizing a cupped Xed contact member and a cylindrical inertia contact member movable into engagement therewith, one of the contact members being provided with means for locking. the two together upon.- their;` cheesesment.

These and other objects; oi` ourfinyentionwill become more apparent from the detaileddescrip?. tion to follow and from the drawn-lgs,V in; which:

Fig. 1 is a central longitudinal section of a. preferred embodiment of: our improved; inertia operated switch when. in: its: Open-C` .Guit 1195i tion, the partsbeing shown in elevati n;

Fie. 2 isa similar viewi` showing; theswitohin: its closedgcircuit position;

Fie. 3 is a, oontralloneitudinal. section taken on the line 3 3 of Fig. 1, the parts again being shown in elevation;

Fig. 4 is a crossesection takenv ontheline fie-4. ofi-Eig. 1';

Fig. 5 is a perspective viewof the movable con-sf tact member; and

Fig. 6A is a cross-section taken on the line 6 6- of Fig. 2.

Referring now to-the drawings, the switch comA prises a support member l0 which may be made of any suitable` insulating material. Included Withinvsupportrnember I0 is anopening I'2` com-A posed of a series of axial bores |3y i4; I 5 andv 125, the last of which communicates with an outlet passage FI, The bores I3V to i6 are preferably or progressively smaller diameters, thereby producing aV succession of stop shoulders` I8, IQnandy 20;

A tubular member 2| which, inthe present em bodiment, is made of; metallic material,v is/pro-V videdwith an upper;portionzZ-Zsand aA lowerportion 23pf-s-malle;` diameter providing anosetlk which is adapted to seat upon shoulder` 13",., The bottom face ofthe tubular; portion- 23.` rests. more shoulder i9.

' The iixed contact oi our. switch comprises a cupped. member 25. may be of copper or Someother. suitable electrically Conductive material, andsrositi nedwithintne bore mythe bottoinoi the. contrasting uoonshoulder 2o. The open top of member 25' is chamfered at 26 and is spaced at 21 from the bottom of tubular section 23.

A conductor 23 may be soldered or otherwise secured to the bottom of the cupped contact member 25 and may be led out of the switch body through passageway il. A similar conductor 29 may be likewise secured to the body of a copper sleeve 3i? which is secured within the tubular section 22.

The metallic sleeve 38 is formed with oppositely positioned lugs 33 at the bottom thereof. The ends of the lugs are secured together to form a closed loop to which is attached a bight portion 34 formed at one end of a closely coiled helix 3| which, in the present embodiment, is made of a highly ductile material such as soft copper.

The inertia contact member of our switch is a solid cylindrical member 32 which is provided with oppositely disposed axial grooves 39. An open link member 38 which is metallic and preferably resilient is securedto contact member 32 by the grooves 39. A bight portion 4|] of the link 38 is coupled to a complementary bight portion 35 formed at the bottom end of tie member 3|.

The inertia contact member 32 has a tapered surface 36 formed at the bottom to permit unimpeded entry into the cupped contact member 25 and one end 4| of the link member 38 is bent so that it projects beyond the cylindrical surface of contact member 32. Thus when contact member 32 enters cupped member 25, the projecting end portion 4| will score the inside of the cupped contactI as at 42 and lock the

contact members

32 and 25 together.

The operation of our switch will be obvious. Assuming that the switch is installed on the inside of aprojectile, the contacts are in the position shown in Fig. 1, while the projectile is in a rest position. When the projectile is fired from a gun, however, the acceleration of the projectile and hence the switch will cause the inertia contact member 32 to exert a force upon the coiled tie member 3| in accordance with the equation Force-:MassXAcceleration Being of a ductile material, the latter will be axially extended until its shape is substantially as illustrated in Fig. 2, permitting contact member 32 to enter cupped contact member 25 and complete a circuit between conductors 2B and 29 which may be provided to detonate a powder charge within the projectile. This circuit has not been illustrated as it does not form a part of our invention.

The size of the wire constituting the coiled tie member 3| and the internal diameter of the coil together with the combined masses of the cyl- 11' inder 32 and link member 38 will of course be determined by the degree of acceleration involved. `For example, where accelerations are of the order of 8,000 g, g being equal to the acceleration due to gravity, we have found the fol- .l

lowing to be satisfactory:

1. Tie member 3|-soft copper-diameter .020"- internal diameter of coil .040"-5 turns 2. Link member Sli-beryllium copper-diameter 3. Combined mass of contact member 32 and link member 38:275 milligrams While the embodiment of our invention which has been described represents a preferred form of our invention, it will be evident that modications and changes therein may be made by those skilled in the art without departing from the spirit and scope of our invention and from the appended claims.

Having thus set forth and disclosed the nature of our invention, what is claimed is:

1. In a projectile including an electric circuit therein, an inertia switch carried internally of said projectile for controlling said circuit comprising a support, a cupped fixed contact member carried by said support, a complementary cylindrical contact member adapted to be received in said cupped contact member, a coiled ductile tie member, one end of which is connected to said support and the other end to said cylindrical contact member for initially spacing said contact members apart, said cylindrical contact member being movable when said projectile is subjected to a predetermined degree of acceleration to axially extend said tie member and enter said cupped contact member, and locking means carried by one of said contact members to lock said contact members together as said contact members move into engagement with each other.

2. In a projectile including an electric circuit therein, an inertia switch carried internally of said projectile for controlling said circuit comprising a support, a cupped fixed contact member carried by said support, a second complementary inertia responsive cylindrical contact member adapted to be received by said xed contact, said second contact member including a pair of oppositely disposed axial grooves therein and an open link member carried in said grooves with one end of said link member projecting beyond the cylindrical surface of said second contact member, and a coiled ductile tie member, one end of which is connected to said support and the other end to a bight portion of said link member to initially space said contact members apart, said second contact member being movable when said projectile is subjected to a predetermined degree of acceleration to axially extend said tie member and enter said cupped contact member whereby the end cf said link member projecting beyond the cylindrical surface of said second contact member will score the inner surface of said cupped contact member, causing said contact members to be locked together.

ROBERT M. BLEAKNEY. EVERLY J. WORKMAN.

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

UNITED STATES PATENTS Number Name Date 1,336,828 Edwards Apr. 13, 1920 FOREIGN PATENTS Number Country Date r188,175 French 1935 602,624 French 1925