Patent Publication Number: US-2009235838-A1

Title: Selectable delay mechanism for pyrotechnic munitions

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to U.S. Provisional Application Ser. No. 61/038,003, filed on Mar. 19, 2008. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of pyrotechnic munitions used to redirect, control or incapacitate targets and specifically, a variable delay system which enables the operator to select the desired engagement distance for the munition. 
     BACKGROUND OF THE INVENTION 
     Pyrotechnic munitions can be produced in a number of different configurations and calibers. One configuration type is the burning smoke or riot agent-emitting munition. These munitions are designed to carry their payloads downrange and begin emitting their contents once the predetermined delay time has been reached. Another munition configuration example is the aerial deterrent. In this configuration, the payload is propelled down range and is designed to discharge in the air above the target after the predetermined delay time has been met. 
     Each munition round type or configuration will employ a delay mechanism designed specifically for that round. Previous types of delays may comprise a simple burning timed fuze, a pressed delay composition or a combination of both. The delays may be initiated directly from the shell discharge itself or by another direct or indirect initiation method. 
     While prior delay configurations for these munitions employ many advantages and disadvantages, they all share a common problem. The problem is the delay must be designed in conjunction with the intended operational range. This limits the rounds capabilities to a single specific operational distance. The operational distance may hinder the end user&#39;s ability to safely discharge the munitions due to lack of, or excessive distance to the target. In addition, users of these munitions must maintain a number of supplies of munitions having various delays so that they are available for a specific application. In addition to storage and transportation issues, errors can be made in selecting a munition having an unintended delay mechanism whereas the munition can detonate prematurely or too late for its intended application. Consequently, a need exists for a variable delay mechanism which enables an operator to select the desired engagement distance for the particular application of the pyrotechnic munition. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a selectable delay mechanism for a pyrotechnic munition that will permit its use at different operational ranges. The delay times, may be physically selected by the operator prior to deployment of the munition. Incorporating a selectable delay mechanism provides for versatility of up to four delay munitions into a single adaptable unit. The selectable delay mechanism of the present invention includes a fuze core, an indexing sleeve and an indexing ring which can be adjusted to select the specific delay time prior to detonation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of the delay mechanism of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS INVENTION (SHOULD BE INVENTION?) 
       FIG. 1  illustrates the selectable delay mechanism  10  of the present invention. The selectable delay mechanism  10  is for a pyrotechnic munition which permits use of the munition at different operational ranges. The selectable delay mechanism includes a fuze core  12  positioned within an indexing sleeve  14 . Fuze core  12  has a hollow cylindrical lower portion  16  for placement of ignitable delay materials  18 . The lower portion  16  includes a number of ports  20  running longitudinally along the centerline of the lower tubular portion, each spaced at a specific distance and angle from one another. Three ports are shown in  FIG. 1  for illustrative purposes. The lower portion  16  of the fuze core  14  is positioned within a hollow cylindrical interior  22  of the indexing sleeve  14 . The fuze core is positioned within and sealed with the hollow interior of the indexing sleeve by a sealing ring  24 . Ring  24  is positioned within a groove  26  in the fuze core and a corresponding groove  28  in the indexing sleeve. Sealing ring  24  can be an O-ring or other material used to form a seal between the fuze core and the index sleeve. 
     Positioned along an upper portion  30  of the fuze core is an index ring  32  which is shaped or keyed in such a way that it is able to move along the centerline axis but not rotationally around the centerline of the mechanism. A pressure spring  34  applies pressure against the index ring and is held in place by a retaining  36 . 
     The fuze core is pressed into the index sleeve until the sealing ring locks in to the grooves within the index sleeve. The index sleeve also has ports  38  along its centerline at a specific distance and angle from one another which line up with corresponding ports  20  in the fuze core, directing the delay emission to the pyrotechnic mix  40  contained within the munition  42 . The index sleeve  14  is attached to a lower portion  44  of the main projectile body of the munition  42 . 
     When assembled into the munition  42 , the fuze core protrudes slightly from an end of the projectile. A screwdriver or other tool is utilized to select the desired range or delay time by turning the fuze core inside the index sleeve. As the delay core is turning inside the index sleeve, the turning force applied is forcing the index ring up and out of an index groove against pressure applied by the pressure spring. As the fuze core is rotated, pressure on the index ring will cause it to drop in to the next index groove on the index sleeve. In each index position, a port in both the fuze core and index sleeve are in alignment. The further the ports are from the initiation of the delay composition, the longer the delay. 
     The delay composition contained within the fuze core can consist of a single time delay fuze or multiple strands of timed delay fuze. Alternatively, the selectable delay system can include delay composition consisting of single pressed column delay, a multiple individual pressed column delay, or a single multi-staged pressed column delay. 
     An alternative arrangement for indexing the fuze core and the index sleeve can be by means of a spring loaded detent pin or other indexing means such as interference grooves, locking rings, set screw or other mechanical fasteners.  FIG. 1  illustrates the O-ring/groove orientation as reference numeral  24 . However, reference numeral  24  can also be referencing the alternative indexing mechanisms. 
     Although the present invention has been described and illustrated with respect to a preferred embodiment thereof, it is to be understood that changes and modifications can be made therein which are within the full intended scope of the invention as hereinafter claimed.