US2637791A

US2637791A - Inertia switch

Info

Publication number: US2637791A
Application number: US172581A
Authority: US
Inventors: Bleier Stanley
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1950-07-07
Filing date: 1950-07-07
Publication date: 1953-05-05
Anticipated expiration: 1970-05-05

Description

Patented May 5, 1953 UNITED STATES PATENT OFFICE INERTIA SWITCH Stanley Bleier, Asbury Park, N. J., assignor to the United States of America as represented by the Secretary of the Army Application July 7, 1950, Serial No. 172,581

(Granted under Title 35, U. S. Code (1952),

see. 266) 6 Claims.

ter consists of a small, self-contained, cylindri cally-shaped unit including a microwave receiver, a microwave transmitter, and an electronic detonator exciter. Such a beacon is used as a tracking aid inmissiles or similar devices. In operation, the electronic detonator exciter is energized only by a received signal having a specific characteristic, and it responds to such signal to effect the firing of an externally-connected electric detonator.

With the beacon installed in a rocket or other missile, there is the danger of premature detonation of the firing circuit, with consequent damage to the missile and possible serious injury to personnel.

With the foregoing in mind, it is oneof the objects of my invention to provide an improved inertia switch adapted particularly for use in transponder beacons and which, by virtue of its structural and operating characteristics prevents the firing circuit of the detonator excited unit from functioning until the rocket or missile is far enough away in its flight from the launching site. Accidental discharge, therefore, would not be too dangerous.

Other objects and advantages will hereinafter appear.

For the purpose of illustrating my invention, an embodiment thereof is shown in the drawing, wherein Figure 1 is a front, elevational view of an inertia switch embodying and operating in accordance with my invention;

Fig. 2 is an elevation'al view, looking toward the left in Fig. 1;

Fig. 3 is a section taken on the line 3-3 in Fig. 2; and

Fig. 4 is a view similar to Fig. 8, and illustrativ of the operating action.

In my improved inertia switch, a compressed spring II) is effective to hold a piston II yieldingly in the extreme lefthand position in a cylinder I2, as shown in Fig. 3. A switch unit I4 is disposed between two plates I5 and IS with which the cylinder structure is provided, and is fixed to the latter by studs I! which pass through plate I5 and are screwedinto the insulating base I8 of the switch unit.

A fixed contact I9 and a movable, spring-contact 20 are disposed in the base I8 in the relative positions shown, and are held in place by the terminal studs 2I and 22, respectively. Extending through spring-contact 20 and insulated therefrom by a bushing 23, is a pin 24 which is held or locked in 'a raised position, as shown in Fig. 3, when engaged with the outer cylindrical surface of piston II In this position, pin 24 holds or looks spring-contact 20 out of engagement with contact I9.

When installed, for example, in a transponder beacon, the cylinder I2 01 .my improved inertia switch is fixed with respect to the beacon casing, and the arrangement or orientation is such that the direction of travel from the launching site is toward the left as viewed in Figs. 3 and 4, and in line with piston I I and cylinder I2. Due to the accelerationof cylinder I2 when the rocket and the beacon contained therein are launched, and because of the inertia of piston I I, the latter will lag behind cylinder I2 and the tension of spring ID will increase'in proportion to occurring movement of the cylinder relatively with respect to the piston. In a specific design, the action was such that piston I I would assume the relative position shown in Fig.4 only at an impact of about 5 Gs acceleration, and then only if such acceleration were maintained for approximately ten seconds. There were two factors which entered into this characteristic action. One of these was the adjustment of screw-25 to vary the initial tension of loading spring Ill. The other factor was the damping or dash-pot action provided by the continuous passage 26, Z'Ifroni one end of piston II to the other end thereof. By choosing the right, respective diameters for the

passages

25 and 21, the permissible rate of air-flow through piston II is obtained to'give the correct amount of damping or dash-pot action for the operating characteri tics desired.

\Vhen the impact is suflicient as the rocket is launched, and when the rate' of acceleration persists for the predetermined number of seconds, piston II will reach the position shown in Fig. 4, relatively with respect to cylinder I2. Pin 24 will then be free to slip off the end of cylinder I2 under the spring-action of contact 2n, and the latter will engage contact I9, as shown, to effect completion of the firing circuit of the detonator exciter unit referred to.

To reset my improved inertia switch, an upward pull is exerted on the knob 28 fixed on the end of pin 24, until the latter clears piston II which is then free to snap back to its initial position shown in Fig. 3, under the loading force exerted by spring Ill.

In the; specific design referred to, the length of piston M was, one inch, and! the. diameter of the bore 01' passage '26 was approximately .016 inch. The respective dimensions of the other parts were in proportion, as shown in th drawing, all the figures of which are drawn to thesame scale.

Examples of other specific; uses to; which my improved inertia switch might be put are shown. in Patent No. 915,246, issued March 16, 1909,,to- Harry F. Stratton, in Patent No. 21883144; is-

sued January 23, 1940, to Frank A, Eytman, and;

in Patent No. 2,431,027, issued November-1.8, 1.947., to John W. Busacker et a1.

One of the broader aspects of my invention resides in the provision of an inertia switch wherein some suitable means, such as the compressed spring I 0, operates to hold two. members such as cylinder ['2 and; piston, H yieldingly in: an.- initial relative. position as shown. in: Fig. 3, and wherein there is incorporated some, form of switch means suchas the: unit M1 arran ed to beopened when the two members are inthe initial relative position and to be closed when these members: are in a second relative position; as shown. in Fig 4.

While but one embod ment: of my invention has been and describeditiwill' be understood! by those skilled" in. the art; that: various modifications, such as in the size, shape and arrancement of the parts. might be made without departin from the spirit of nay-invention, or the scope of the claims.

The invention claimed is:-

1. In an inertia switch of the character described, a. cylinder; a piston disposed in said cylinder and mo able relatively with respect thereto. from an initiai position at; one end of said cylinder to: a second position. toward the other end or said cylinder, a. coil spring compressed between said piston and said. other end of; said cylinden. and: a switch unit disposed at one side of said? cylinder: said unitcomprisinc a base of insulating material fixed to; said cylinden a switch contact fixed in said? base, and a sprin contact. supported by said base and; movableinto and out of engagement" with said: fixed contact, saidv spring-contact beinggpnovided with a. pin one: end of which extends loosely through said: base-and? through the adjacent: cylinder; wall for engagement with the: cylindrical surface of said piston to hold said spring-contact. disengaged: fronr said fixed contact, the; disposition: of said; pin longitudinally of said. cylinder bein such that: with. saidpist'onin said second: "position thereof said pin; is released. by' said piston to permit engagement. of; said spring-contact with said fixed contact, said piston, being: provided with a passage OfrelatiVeIy small" cross-sectional area and extending from: one. end? to the: other end; of said piston. to; effect: a dash'spot action against a relatively rapid movement of? said. piston from said; initial; position to said second position, thereof, the:- other end off said pin. protruding from said" base to. permit withdrawal! of. said pinout of said cylinder.

2. In an. inertia. switch of the: character described, a cylindenprovided' on onesidethereof with two plates spaced? and parallel with respect to each other; a piston disposed in said cylinder and movable relatively with respect thereto from an initial position at one end of said cylinderto a second position toward the other end of said cylinder,-a coil spring compressed between said piston and said other end of said cylinder, and a switch unit disposed between and fixed to said plates; said, unit. comprising a base, of insulating material, a; switch contactfixcd in saidbase, and a U-shape spring-contact disposed within said base and fixed to the latter at one end, the other end of said spring-contact being disposed for movement into and out of engagement with said fixed. contact, saidspring-contact being provided at said. other end thereof with a pin one end of which; extends .loosely through said base and through the adjacent cylinder Wall for engagement with the cylindrical surface of said piston to-hold said other end of said spring-contact disengaged from said fixed contact, the disposition of said pin longitudinally of said cylinder being such that with said piston in said second position thereof said pin is: released by said piston to permit engagement of said other end of said springrcontactwith said, fixed contact...

3,. In,v an inertiaswitch of the character described, a cylinder, a piston disposed in said cylinderand movable relatively with respect thereto from an initia1 position at one end of said cylinder to av second position toward the other end of said cylinder, a. spring compressed. between said piston and. said. other end of said cylinder, and a switch unit disposed atone side i of said cylinder; said unit comprising a base. of

insulating material fixed to said cylinder, a switch. contact fixed in. said base, and a. springcontact. supported bysaid base and. movable into and out: of engagement with said fixed contact, said. spring-contact being providedwithapin one end of which extends loosely through said base and through the adjacent cylinder wall for engagementwith the; cylindrical surface of saidpiston to hold said spring-contact disengaged from said fixed contact, the, disposition of said pin longitudinally of. said cylinder being. such. that with said piston, in. said second. position thereof saidv pin" is released by said piston to permit engagement of said spring-contact with said fixed contact and, said pistonbeing provided with a passage extending fromone. end to. the other end of said piston.

4., In an inertia switch of the character described, a cylinder, a piston disposed in said cylinder and movable relatively with respect thereto from an initial position at. one end of said cylinder to; a. second position toward the other end of said cylinder, a spring compressed between said piston and said other end of said cylinder, and switch means spring-biased to one position and having at least one part thereof engageable with said piston and disposed to be locked in another position. by virtue of such ongagement, said piston being provided with a passage extending from one end to the other end of said piston to regulate the movement of said piston.

5'. In an inertia: switch. of. the. character described, a cylinder, a piston disposed in said cylinder, a spring compressed between said piston and one end of said cylinder, and switch means spring-biased to onevpositi'on and having at least one part thereof engageable with the cylindrical surface of said" piston, and disposed to. be locked in another position by virtue of said engagement, said piston being movable axially along said cylinder to a given position toward said one end of the latter to disengage said part from said cylindrical surface thereby to effect movement of said switch means to another posi- References Cited in the file of this patent UNITED STATES PATENTS Name Date Boothroyd Mar. 15, 1938 Number Number Number Name Date Gilbert July 28, 1942 Gilbert Oct. 6, 1942 Haiderson Oct. 17, 1944 FOREIGN PATENTS Country Date Germany July 2, 1932 France Dec. 28, 1925