US2939393A

US2939393A - Vented safety squib arming device

Info

Publication number: US2939393A
Application number: US710634A
Authority: US
Inventors: Kenneth A Johnson; James A Ousley; Willmer N Stark
Original assignee: General Precision Inc
Current assignee: General Precision Inc
Priority date: 1958-01-23
Filing date: 1958-01-23
Publication date: 1960-06-07
Anticipated expiration: 1977-06-07

Description

June 7, 1960 K. A. JOHNSON ETAL 2,939,393

VENTED SAFETY SQUIB ARMING DEVICE Filed Jan. 23, 1958 2 Sheets-Sheet 1 INVENTOR. KENNETH A. JOHNSON JAMES A. OU SLEY BY WILLME N. STARK ATTORNEY June 7, 1960 K. A. JOHNSON ETAL 2,939,393

VENTED SAFETY SQUIB ARMING DEVICE 2 Sheets-Sheet 2 Filed Jan. 23, 1958 INVENTOR. KENNETH A. JOHNSON JAMES OUSLEY /W|LL N. STARK M,

ATTORNEY VENTED SAFETY SQUIB ARMING DEVICE Kenneth A. Johnson, Pleasanton, and James A. Ousley and Willmer N. Stark, Liver-more, Calif., assignors to General Precision, Inc., a corporation of Delaware Filed Jan. 23, 1958, Ser. No. 710,634

2 Claims. (Cl. 102-70) This invention relates to a new and improved safety squib, and more particularly to a novel vented safety squib arming device adapted to ignite a rocket propellant, or the like.

Heretofore, disastrous premature firings of propellants for rockets, or the like, have been caused by ignition of the main propellant charge by the squib before the preparations for'firing have been completed.

An object of this invention is to provide a squib having a safety mechanism formed as an integral part. thereof which will prevent the premature firing of the main propellant by accidental ignition of the squib.

Briefly described, our inventionprovides a squib having a ported rotatable plate located Within a housing. On one side of the plate, and lying within the same housing, is a squib package. On the other side of the plate is a plug having both an ignition passage and a vent passage. The ignition passage leads into a propellant chamber and the vent passage is sealed off tightly from the ignition passage and is opened into the atmosphere, or other suitable media.

The ported rotatable plate can be actuated either by hand or a suitable motor such as a low current torque motor associated with and operating an arm/safe switch, whereby when the squib is in an unarmed, or armed position, the plate is turned so that the ignition passage is closed and sealed off from the squib package and the vent passage is open. When the switch and squib are both armed, the ported rotatable plate is positioned so that the ports therein are positioned so as to permit open communication through the ignition passage from the squib to the propellant charge and at the same time the vent passage is closed. There is also provided a suitable check valve over the ignition passage to prevent blowback into the squib chamber when the main propellant charge is burning. If desired, suitable packing may be provided between the rotary plate and the plug containing the ignition passage and the vent passage.

Other objects and advantages of this invention will become apparent as the discussion proceeds, and when taken in consideration with the accompanying claims and drawings, in which:

Figure 1 shows a perspective view of the outside housing of a combination squib and arm/safe switch suitable for firing a propellant in a rocket;

Figure 2 shows a cross-sectional view taken on the line 22 of Figure 1;

Figure 3 shows a cross-sectional view taken along the line 33 of Figure 2;

Figure 4 shows a cross-sectional view taken along the line 4-4 of Figure 3;

Figure 5 shows a cross-sectional view taken along the line 5-5 of Figure 3, and;

Figure 6 shows a cross-sectional view taken along the line 6-6 of Figure 3 showing the position of the ports in the rotary plate.

Turning now to a detailed description of our invention,

Patented June 7, 1960 the numeral 10 designates generally a cylindrical casing housing the squib and other mechanism embodying our invention. The numeral 11 designatesgenerally a second cylindrical casing housing a motor such as at low current torque motor and an arm/safe switch, or the like. It is here pointed out that the motor and arm/safe switch does not form a part of this invention, and a complete description thereof is unnecessary for anunderstandin'g of the operation of our squib. Therefore, for the purpose of simplicity, no further description of the construction and operation of this motor is deemed necessary. It is hereby pointed out that if desired them'echanism of our squib can be operated manually, as willv be further explained later.

Turning now to a detailed description of the internal mechanism of the squib embodying our invention, and as shown in cross-sectional view of Figure 2, the-numeral 12 designates a squib package encased in a supporting member 13. The squib 12 and supporting member 13, together with the electrical igniter 14, maybe of conventional design and configuration. Centrally disposed within the housing 10, and extendingpartially and centrally therethrough, is .a tubular support member 15, through which a shaft 16 is rotatably mounted. Shaft 16 desirably extends into-motor casing, 11, and: preferably is supported and sealed in casing 11 by means of bearing.

17. On the end of shaft 16 there is provided a groove 18 for the purpose of receiving tongue 19 located on shaft 20 formed'integral with, or attached to a rotary valve plate 21. Rotary valve plate 21 is provided with a pair of ignition ports 22 and a pair of vent ports 23, as best shown in Figure 6.

Positioned on the side of rotary valve plate 21 opposite the squib package 12 is a plug 24. Plug 24 is provided with a vent passage 25 and an ignition passage 26. If desired, the faces of the plug 24 and the rotary valve plate 21 can be lap-ground for the purpose of providing a tight seal between the rotary valve plate 21 and the plug 24. On the other hand, if desired, the plug 24 can be sealed by means of a 0 ring 27 located between the walls of the housing 10 and the plug 24, and the vent passage 25 can be sealed by means of an 0 ring 28, and the ignition passage 26 can be sealed by means of another 0 ring 29. Closing the opposite side of the ignition passage 26 is a spring loaded check valve 30 located within a chamber 31 communicating with a passage 32. The chamber 31 and passage 32 are located within an L having a flange 34 thereon, and which is supported to flange 35 formed integral with housing 10. If desired, threads 36 may be formed on the L for the purpose of attaching the squib assembly to a suitable housing containing a propellant charge (not shown). Vent passage 25 is in communication with a port 37 which may exhaust to the atmosphere, or into any other suitable chamber, as desired. Further, if desired, a blow out plug 38 can be provided to lightly seal the port 37 from the entrance of dirt, dust and the like.

Attention is now directed to Figure 2 and Figure 6 for an explanation of the placement of the ignition port 22 and vent ports 23. In the position shown in Figures 2 and 6, the ignition ports 22 are over the ignition passage 26, preventing open communication between the passage 32 leading into the propellant chamber and the vent ports 23, and out of position over the vent passage 25. In this position the squib is set to be armed. Upon the rotation of the rotary valve plate 21 in a counterclockwise direction, or to the left in Figure 6, the ignition ports 22 are moved away from the ignition passage 26 and the vent ports 23 are moved into position opening the vent passage 25. In this position the squib is said to be armed.

Turning now to a description of the operation of our invention, it is desirable to consider the rotary valve plate 21, in effect a rotary valve which moves from an arm/ safe to an armed position until manually, or with a switch contained within the housing 11, and is actuated by a rotation of shaft 16. When the squib is safe" the ports 22 in valve plate 21 close the ignition passage 26 and at the same time the ports 23 open the vent passage 25. In this position accidental firing of the squib package 12 would prevent the expanding gas from entering a chamber 31 and passage 32 by means of the seal formed by the rotary valve plate .21, and would permit'escape of the hot burning gasses from the squib 12. out through the vent 37, the vent ports23 being open to cause open communication throughthevvent to the squib package 12; 'When it is desired to arm the squib, the rotary valve plate 21 is rotated clockwise and the valve ports 23 close the vent passages 25 and the valve ports 22 open the ignition, passage '26, whereby firing of the squib permits passage of the burning gasses through ignition passage 26 into chamber 31 and through passage 32 into the main propellant for firing or ignition thereof.

Spring-loaded check valve 30 is provided over ignition passage 26 in order to prevent blow-back into the housing of hot gasses from the main propellant through the passage 32 and the chamber '31.

It is to be understood that changes in material, size and shape of the various mechanisms making up our invention can be resorted to without departing from the spirit of our invention, as set forth in the appended claims:

2,939,393 a g V a We claim:

1. A vented safety squib arming device comprising a cylindrical housing, a squib package inside said housing, a plug in said housing having an ignition passage and a vent passage therein, a check valve operably closing said ignition passage and a rotary valve plate in said housing positioned between said squib package and said plug, said plate having ignition ports and vent ports therein, a rotary drive shaft extending axially of said cylinderand through said squib package and connected to and driving said rotary valve plate, said ports in said plate being positioned to alternately coincide with the ignition passage in the plug and the vent passage in the plug to open the ignition passage to said squib package and simultaneously close the vent passage to said squib package as said plate is rotated by said shaft when said squib is armed and close the ignition passage and simultaneously open the vent passage when said squib is arm/safe.

2. A vented safety squib arming device according to claim 1, in which there is provided an O ring seal means surrounding each of said passages, one of said O ring seal means also being positioned in said plug to make a sealing cont-act with the surface of said rotary valve plate lying adjacent said plug.

References Cited in the file of this patent UNITED STATES PATENTS 2,586,437 Rabinow Feb 19, 1952 2,779,284 Kane Jan. 29, 1957 2,808,000 Lindsay Oct. 1, 1957