US3173635A

US3173635A - Preejection sequencer for aircraft

Info

Publication number: US3173635A
Application number: US335703A
Authority: US
Inventors: William H Simmons
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-01-03
Filing date: 1964-01-03
Publication date: 1965-03-16
Anticipated expiration: 1982-03-16

Description

March 16, 1965 W. H. SIMMONS PREEJECTION SEQUENCER FOR AIRCRAFT Filed Jan. 5, 1964 INVENTOR. WILLIAM H. SIM MONS BY 777. 6 0/615 Mm J.

ATTORNEY United States Patent 3,173,635 PREEJECTION SEQUENCER FGR AIRCRAFT William H. Simmons, Houston, Tex., assignor to the United States of America as represented by the Secretary of the Army Filed Jan. 3, 1964, Ser. No. 335,703 2 Claims. (Cl. 244-122) (Granted under Title 35, US. Code (1.952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to preejection apparatus for aircraft.

In such apparatus, a number of propellant actuated devices have to be operated in sequence, close together in time and automatically. The number of such devices may be too large for a crewman to operate manually in the desired order under stress of necessity for haste and possible danger. In event any propellant actuated device fails to function, then those devices dependent upon it for being later actuated will also fail to function. Manually operated initiators have been tried at critical locations but beside leaving much to human error, have an undesirable increase in weight.

An object of this invention has been to reduce the weight in this type apparatus, enhance its reliability, simplify its construction and improve its accuracy over an extended range of environmental temperatures.

According to this invention, this preejection apparatus has been simplified and made lighter and made more reliable. Specifically, the functions of two gas pressure sources and the pyrotechnic delay train have been combined into a single device which replaces the first gas pressure source with the result that the preejection apparatus is not only simplified but made about 12% lighter in weight and with a significant gain in reliability. In addition, this inventon significantly improves the timing accuracy of the apparatus by eliminating the pyrotechnic delay train which is undesirably sensitive to variations in environmental temperature.

Referring to the drawings:

FIG. 1 is a diagrammatic representation of the preejection apparatus of this invention including the sequencer of FIG. 2.

FIG. 2 shows a preferred embodiment of the sequencer of this invention.

Referring to FIG. 1, a solid propellant pressure type sequencer 11, shown also in FIG. 2, is connected by a gas pressure line 12 leading to a dump valve 15 for reducing cabin pressure to a safer level before personnel are ejected in the customary manner in their seats. Another pressure line 13 from sequencer 11 leads to a canopy unlocking mechanism 14 to be actuated after a usual predetermined time interval has elapsed subsequent to actuation of the valve 15. The canopy jettison device 16 is operated in the usual manner after the functioning of canopy unlock mechanism 14. In the event of failure of the mechanism 14 to actuate device 16, then to insure that the device will nevertheless function, another pressure line 17 leads from sequencer 11 to the device 16.

In FIG. 2, the sequencer of FIG. 1 includes a fluid pressure cylinder 24 closed at one end by a pressure cap 8 and firing head 23 and containing a propellant charge or cartridge 9 and means familiar in the art for actuating said charge electrically, mechanically or pneumatically. Orifice is located at the end of said cylinder opposite pressure cap 8 and is covered by a separable or frangible cover 18 to retain the control fluid in cham- 3,ii3,635 Patented Mar. 16, 1965 her 25 until its discharge is desired. Fluid discharge control rod 26 is afiixed to piston 27 and extends through said orifice, thus restricting said orifice to a desired area for fixing a basic maximum fluid discharge rate. When pressure generated by charge 9 has increased to a designed level in chamber 28 the cover 18 is removed or ruptured and said piston and control rod move up-- ward with their velocity being controlled by the dis= charge rate of the control fluid through said orifice.

Pressure lines

29, 30 and 31 are sequentially uncovered at designated time intervals to supply pressurized gas in a timed sequence to whatever they may be connected in a manner corresponding to the

pressure lines

12, 13 and 17 in FIG. 1. Indentations or cuts 19 at appropriate locations in the control rod 26 reduce the cross-sectional area of this rod and increase the effective orifice area at times corresponding to the opening of successive pressure lines. Changeable orifice inserts may be provided to permit ready variation of the basic fluid discharge rate thus permitting a single device to be used in difierent apparatus. Similarly, changeable control rods of suit-- able configuration may be provided to permit the device to be adapted to varied sequential programs in different apparatus. O-ring 21 prevents fluid from chamber 25 from entering the pressure lines and O-rin'g' 22 provents gas from chamber 28 from prematurely entering the pressure lines. 7

To obtain a substantially uniform propellant burning rate is believed within the skill of the art. An alternate way of obtaining substantially uniform pressure, involves what is known as a high-low system wherein propellant is supplied at any conventient rate to a high pressure chamber and metered into a lower pressure chamber at a substantially constant rate. Any well known suitable type of primer or initiator may be used for firing the propellant cartridge.

I claim: H

1. In an aircraft preejection apparatus including it source of gas pressure, means comprising a dump valve actuated by gas from said source for dropping cabin pressure, a canopy unlocking means, a time delay device between said source and said canopy unlocking means whereby cabin pressure is dropped before the canopy is unlocked, means for jettisoning said canopy after it has been unlocked, the combination therewith of the improvement for simplifying said apparatus and reduc-- ing its weight, said improvement including a corribinaton of said source of gas pressure and said time delay device into a single unit of sequencer type thruster including a cylinder and piston therein, a propellant in said cylinder, a control rod connected to said piston and projecting out of an end wall of said cylinder, said rod having spaced portions of reduced diameter for controlling a cushioning delay between said piston and a cylinder end wall through which said control rod extends, said cylinder being provided with a plurality of exhaust ports sequentially uncovered by said piston, a pressure line leading from a first exhaust port uncovered by said piston and leading to said dump valve, and second pressure line leading from a second exhaust port uncovered by said piston to said canopy unlocking means.

2. Apparatus according to claim 1 in which a third pressure line leads from a third exhaust uncovered by said piston to said canopy jettisoning means.

References Cited by the Examiner UNITED STATES PATENTS 1,915,435 6/33 Miller 891.01 2,370,526 2/45 Doran 6053 2,892,602 6/59 Servanty 244.-122.

FERGUS S. MIDDLETON, Primary Examiner.v

Claims

1. IN AN AIRCRAFT PREEJECTION APPARATUS INCLUDING A SOURCE OF GAS PRESSURE, MEANS COMPRISING A DUMP VALVE ACTUATED BY GAS FROM SAID SOURCE FOR DROPPING CABIN PRESSURE, A CANOPY UNLOCKING MEANS, A TIME DELAY DEVICE BETWEEN SID SOURCE AND SAID CANOPY UNLOCKING MEANS WHEREBY CABIN PRESSURE IS DROPPED BEFORE THE CANOPY IS UNLOCKED, MEANS FOR JETTISONING SAID CANOPY AFTER IT HAS BEEN UNLOCKED, THE COMBINATION THEREWITH OF THE IMPROVEMENT FOR SIMPLIFYING SAID APPARATUS AND REDUCING ITS WEIGHT, SAID IMPROVEMENT INCLUDING A COMBINATION OF SAID SOURCE OF GAS PRESSURE AND SAID TIME DELAY DEVICE INTO A SINGLE UNIT OF SEQUENCER TYPE THRUSTER INCLUDING A CYLINDER AND PISTON THEREIN, A PROPELLANT IN SAID CYLINDER, A CONTROL ROD CONNECTED TO SAID PISTON AND PROJECTING OUT OF AN END WALL OF SAID CYLINDE,R SAID ROD HAVING SPACED PORTIONS OF REDUCED DIAMETER FOR CONTROLLING A CUSHIONING DELAY BETWEEN SAID PISTON AND A CYLINDER END WALL THROUGH WHICH SAID CONTROL ROD EXTENDS, SAID CYLINDER BEING PROVIDED WITH A PLURALITY OF EXHAUST PORTS SEQUENTIALLY UNCOVERED BY SAID PISTON, A PRESSURE LINE LEADING FROM A FIRST EXHAUST PORT UNCOVERED BY SAID PISTON AND LEADING TO SAID DUMP VALVE, AND SECOND PRESSURE LINE LEADING FROM A SECOND EXHAUST PORT UNCOVERED BY SAID PISTON TO SAID CANOPY UNLOCKING MEANS.