US 3724385 A
Description (OCR text may contain errors)
United States Patent 1191 eatty et al. I
1 51 Apr. 3, 1973  FUZE HAVING A PNEUMATIC AND INERTIA ARMING SYSTEM  Inventors: Bobby D. Beatty, Bloomfield; Gary' D. Butts, Loogootee; Stanley J. Herold, -Switz City; Donald E. LaGrange, Washington, all of ind.
 Assignee: The United States oi America as represented by the Secretary of the Navy 22 Filed: Sept. 20, 1971 21 Appl.No.: 181,791
521 u.s.c1 ..1o2/s1,102/7s  Int. Cl. ..F42c 5/00  Field of Search .ll02/8l, 76, 78, 7O
 References Cited UNITED STATES PATENTS 3,048,111 8/1962 Baker et al. ..l02/8l X 9/1901 Lynch et al ..1o2/s1 2,469,352 5/1949 Lauritsen ..l02/8l 2,872,869 2/1959 Rasmussen ..1o2/s1 2,981,192 4/1961 Grandy .....102/7s 3,583520 6/1971 Gawlick ..102/81 Primary Ekaminer samuel W. Engle Attorney-R. S. Sciascia et al.
 ABSTRACT A fuze for a pyrotechnic device having a firing pin for detonating a primer. An inertia sleeve is provided for preventing forward movement of the firing pin until a pneumatic latch is operated by the pressure supplied by a launching force. A borerider pin is also provided for preventing detonation of the primer while the fuze is inside a launcher barrel.
2 Claims, 6 Drawing Figures PATENTEUAPREJ ms 3, 724. 385
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FUZE HAVING A PNEUMATIC AND INERTIA ARMING SYSTEM STATEMENT OF GOVERNMENT INTEREST The invention described herein. may be manufactured and used by-or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
BACKGROUND OF THE INVENTION The present invention relates to a fuze for a pyrotechnic device, such as a flare, and more particularly relates to a fuze having safety features to prevent accidental arming of the fuze.
Various safety devices are employed to prevent accidental arming and premature ignition of ordnance devices, as ignition of flares, or explosion of bombs or missiles, while aboard a ship or plane, creates a highly dangerous condition. Frequently, an arming' pin, or wire, is provided to prevent actuation of a firing pin until the arming pin is removed. For example; in U.S. Pat. No. 3,316,841, which issued May 2, 1967, to Charles E. McFann and Arnold S. Munach, there is shown a bomb fuze having an arming pin passing through a housing and shaft thereby locking all mova- I ble elements of the fuze until the arming pin is removed.
Another device for arming a fuze uses a setback slide mechanism which responds to setback forces developed during acceleration to arm the fuze. Such a device is shown in U.S. Pat. No. 3,339,488, which issued Sept. 5, 1967, to Julius Borchers. In this patented device, movement of a setback slide pivots a lever and initiates a timing mechanism to release a detonator carrier which moves into an armed position.
SUMMARY OF THE INVENTION The present invention relates to a fuze that is to be attached to an ordnance item, such as a pyrotechnic flare, and which is to be launched through a launching barrel. A setback slide is provided which carries a spring-loaded firing pin and forward movement of the setback slide and firing pin is prevented by a borerider pin. Aft movement of the setback slide is prevented by a locking mechanism which is unlocked by the pressure applied for launching the ordnance item. In the event that the setback slide is unlocked and moves rearward,
if the ordnance item does not clear the barrel, the borerider pin is provided with means for preventing actuation of the firing pin.
BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT tion 11 is comprised of a housing 13 having a bore 14 in the aft end 'in which a pneumatic button 15 is slidably mounted. A shaft 1 6 is attached to the inner end of pneumatic button 15 and shaft 16 passes through a bore 17 in wall 18 of housing 13. A compression spring 19 is provided around shaft 16 between wall 18 and button 14, and a retaining ring 21 is provided on the end of shaft 16 to retain button 15 within housing 13. Button 15. is provided with two annular grooves 22 and 23. A sealing ring 24 is positioned in groove 22 and groove 23 is arranged to'receive a ball 25 that is positioned in a hole 26 that communicates between bore 14 and a second bore 27 in housing 13.
A cylindrical setback slide 28 is positioned in bore 27 and setback slide 28 is provided with a reduced diameter portion 29 that joins the enlarged diameter portion of slide 28 by a tapered surface 31. A spring 32 is provided between one end of setback slide 28 and the end of bore 27 to bias setback slide 28 in a forward direction. A bore 33 is provided in setback slide 28 and a firing pin 34 is slidably positioned in bore 33 of setback slide 28. A ball 35 is provided for locking firing pin 34 in a cocked position and a spring is provided for driving firing pin 34 when firing pin 34 is released. Ball is positioned in a tapered hole 36 in setback slide 28 and the diameter of ball 35 is sufficiently large to extend into bore 27 of setback slide 28 and prevent forward movement of firing pin 34. A hole 37 is provided in housing 13 to receive ball 35 when setback slide 28 moves forward to permit release of firing pin 34.
A borerider pin 38 is provided in hole 39 of housing 13 and borerider pin 38 has a pair of enlarged diameter portions 41 and 42 and a hemispherical portion 43. A
a spring is positioned in hole 39 for biasing borerider pin 38 outwardly from hole 39. As best shown in FIGS. 2 and 6 of the drawings, setback slide 28 has a slot 44 which is sufficiently large to accept pin 38 but prevents the passage of enlarged diameter portions 41 and 42. A fuze cap 45 is threadedly attached to housing 13 and contains a primer 46, delay pellet 47 and ignition pellet 48. As one method of launching the fuze and attached ordnance item is by compressed air, a sealing ring 49 of resilient material is provided around the outer periphery of housing 13 in an annular groove 51 to prevent excessive leakage of air between the outer perimeter of fuze section 1 1 and the inner surface of a launching tube 52.
OPERATION Upon launching fu'ze section 11 and the associated ordnance item, the propelling force, such as that created by an explosion, or such as compressed air, moves pneumatic button 15 against the force of spring 19 and groove 23 becomes aligned with hole 26 in housing 13. Ball 25 is now free to move partially into groove 23 so that setback slide 28 will no longer be in a locked condition. As fuze section 11 is accelerated through launching tube 52, the inertia of setback slide 28 causes spring 32 to be compressed and setback slide 28 moves rearwardly to release borerider pin 38, as shown in FIG. 3 of the drawings. Firing pin 34, however, remains locked with setback slide 28. Spring 40 moves borerider pin 38 so that hemispherical portion 43 contacts launching tube 52 Referring now to FIG. 4 of the drawings, a malfunction condition is shown wherein fuze section 11 has not cleared launching tube 52, but is no longer in motion. Spring 32 will drive setback slide 28 to its original position against borerider pin 38 and firing pin 34 remains in a locked condition by ball 35. In the event that fuze section 11 is removed manually from launching tube 52, the enlarged diameter 42 of borerider pin 38 prevents spring 40 from driving borerider pin 38 out of hole 39.
Referring now to FIG. 5 of the drawings, fuze section 11 has cleared launching tube 52 and spring 40 has driven borerider pin 38 out of hole 39. After the setback force created by the acceleration of the device has diminished, spring 32 drives setback slide 28 forward, as borerider pin 38 is not now present to prevent movement. When tapered hole 36 in setback slide 28 becomes aligned with hole 37 in housing 13, ball 35 moves partially into hole 37 and firing pin 34 becomes unlocked. Firing pin spring 30 then drives firing pin 34 into primer 46 and the detonation of primer 46 ignites delay pellet 47 which, in turn, ignites ignition pellet 48.
It can thus be seen that two sequential events must take place before primer 46 is detonated by firing pin 34. First, pneumatic button 15 must be depressed to release ball 25 and, while button 15 is in this position, setback slide 28 must move in an opposite direction to the movement of button 15, in order to release borerider pin 38. For example, an accidental dropping of the fuze will not release firing pin 34, as two forces acting in opposite directions are required for this actuation.
1. A fuze for a pyrotechnic device compri g,
a housing having first and second longitudinally extending parallel bores,
a setback slide slidably positioned in said first longitudinally extending bore, said setback slide having a reduced diameter portion,
a pneumatic button slidably positioned in said second longitudinally extending bore, said pneumatic button having an annular groove in its periphery,
a firing pin slidably mounted within said setback slide,
spring means for actuating said firing pin,
releasable means for locking said firing pin in said setback slide,
a borerider pin releasably connected to said setback slide and having means for preventing actuation of said firing pin,
a primer ignitable by said firing pin, and
a locking ball in said housing engageable with said reduced diameter portion of said setback slide for locking said setback slide in said housing, said locking ball being receivable in said annular groove of said pneumatic button for unlocking said setback slide whereby said firing pin is actuated upon forward movement of said dpneumaticbutton, then rearward movement of sat setback slide, followed by forward movement of said setback slide.
2; A fuze for a pyrotechnic device as set forth in claim 1 wherein said releasable means for locking said firing pin in said setback slide comprises a second locking ball engageable with the forward end of said firing pin, and a hole in said housing for receiving a portion of said second locking ball thereby unlocking said firing pin.