US 3726220 A
A low impulse sustained power cartridge for an initiator power source of energy to accurately and flexibly control the gas output to a system demand. The cartridge has a metering nozzle or throat constriction mounted in the forward end of the cartridge case adjacent the propellant grain by which a low impulse initial gas pressure is delivered that rounds off at peak pressure to sustain an even slow decay.
Description (OCR text may contain errors)
filtrate Etates atet 1 1 1111 3,726,22fi
MacDonald et al. 5] Apr. 10, 1973 54] CARTRIDGE 3,270,668 9 1966 Silver ..102/20 1 1 Hugh Macvonald, (1119911118911, 333331323 31321 $133112; 6 a1. ....l33
Roger Schultz, phlladelphla; 3,089,419 5/1963 Pollard ..102/39 Lennord L. Pitney, Levittown, both of Pa.
Assignee: The United States of America as represented by the Secretary of the Army Filed: June 1, 1971 Appl. No.2 148,561
References Cited UNITED STATES PATENTS l/l97l Ciccone et al ..23/28l Primary Examiner-Robert F. Stahl Attorney-Harry M. Saragovitz, Edward J. Kelly, Herbert Ber] and William Sommer 5 7 ABSTRACT A low impulse sustained power cartridge for an initiator power source of energy to accurately and flexibly control the gas output to a system demand. The cartridge has a metering nozzle or throat constriction mounted in the forward end of the cartridge case adjacent the propellant grain by which a low impulse initial gas pressure is delivered that rounds off at peak pressure to sustain an even slow decay.
3 Claims, 1 Drawing Figure PAIEmEnA R 1 01% 3,726,220
\NvENTozs HUGH D.MAC.DONALD,JR ROGER SCHULTZ LENNOED PITNEY 4 M MM ATTORNEYS CARTRIDGE The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.
This invention relates to cartridges, and more particularly, to a power cartridge for an initiator.
Existing initiator cartridges have been found unsatisfactory due to their delivering a high peak pressure at initiation and, immediately following, suffering a rapid pressure decay.
It is an object of the invention to provide an initiator cartridge that delivers gas with low impulse initiation and sustaining power.
Another object of the invention is to provide such a cartridge in which the delivered power is a more accurately and flexibly controlled gas output for a system demand.
These and other objects, features and advantages will become more apparent from the following description and accompanying drawing in which the sole FIGURE is a longitudinal sectional view of an initiator containing a cartridge embodying the principles of the invention.
The initiator, shown generally at 10, has a chamber portion 11 provided with a threaded rearward portion 12 for securing initiator cap 13 upon assembly with the improved cartridge 14 seated in the chamber 11. The cap 13 has an appropriate control passage containing an operative firing pin 15 when an actuating device (not shown) is connected to the cap external threads 16. The rearward end of the cap passage is internally threaded to secure a shipping plug 17. A shipping cap 18 similarly protects the forward end of the initiator, particularly during transit and storage, as it is secured to the external threads 19 on the chamber reduced forward nose which has a central energy delivering passage 20. A transverse locking or set screw 21 secures the sealed connection of cap 13 on chamber 11.
The cartridge head has a central passage 22, the rearward portion of which is enlarged to suitably secure primer 23 in fluid communication with the igniter pellets 24 positioned in the rearward end of the forwardly opening cartridge case. A cup-shaped pellet retainer 25 is threadedly secured to an internally threaded surface portion of the stepped internal surface of the cartridge case. The base of the retainer 25 has a plurality of apertures 26 to fluidly communicate pellets 24 with the elongated propellant grain 27 which has a central elongated passage 30 interconnecting its conically recessed end portions 28, 29. A cylindrically shaped inhibitor 31 surrounds the external lateral surface of the propellant grain 27 and, upon assembly, is cemented to the cartridge case internal surface and is in longitudinal alignment with the sidewalls of pellet retainer 25 and nozzle case 32. The rearwardly opening nozzle case 32 is cemerited to the forward internal surface of the cartridge case and has a forward centrally apertured base 33. A metering nozzle member 34, having a central throat constriction 35 intermediate conically tapering approach and exit surfaces 36, 37, is cemented to the inner sidewall of the nozzle case 32 with a rupturable tape seal 38 positioned intermediate the nozzle member 34 and nozzle case base 33 overlying the nozzle base central aperture.
The initiator cartridge provides a low impulse at mitiation and the delivered gas pressure rounds off at peak pressure to sustain an even slow decay, while having the capability to be responsive to changes of load. Thereby adequate propellant gas pressure is supplied to begin operation of a power take-up unit of an inertia reel or the like, without subjecting the unit to a pressure-peak shock. The slow decay sustains the near peak pressure over a time period necessary to operate the take-up reel.
Various modifications, changes or alterations may be resorted to without departing from the scope of the invention as defined in the appended claims.
1. A low impulse sustained power cartridge for an initiator comprising,
a cartridge case having a forwardly opening propellant chamber and a primer in its rearward end, igniter pellet means in said propellant chamber adjacent said primer,
an elongated propellant grain in said chamber and having a central elongated passage therethrough, and
metering nozzle means cemented to the forward end of said cartridge case adjacent said propellant grain and in substantial axial alignment with said propellant grain passage, said nozzle means including a metering nozzle member having a central throat constriction intermediate conically tapering approach and exit surfaces,
said nozzle means including a rearwardly opening cartridge nozzle case cemented to the forward internal surface of said cartridge case, said nozzle case having a forward centrally apertured base, said metering nozzle member being cemented to the inner sidewall of said nozzle case, and a tape seal intermediate said nozzle member and said nozzle case base overlying the base aperture.
2. The structure of claim 1 wherein a plurally apertured pellet retainer is positioned intermediate said pellet means and said elongated propellant grain.
3. The structure of claim 2 wherein said elongated propellant grain has an inhibitor surrounding its external surface, said inhibitor being cemented to the internal surface of said cartridge case and in longitudinal alignment with said pellet retainer and nozzle case.