Ordnance – Cartridge feeding – Belt feed
Reexamination Certificate
1999-01-13
2001-03-20
Carone, Michael J. (Department: 3641)
Ordnance
Cartridge feeding
Belt feed
C089S033170, C089S033160
Reexamination Certificate
active
06202534
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gun system, and an ammunition handling system for a gun. More particularly, the present invention relates to a shell casing unloading device used in the ammunition handling system of a high rate of fire automatic gun.
2. Description of the Related Art
Automatic high rate of fire guns, for example 20 mm M61A1 Gatling-type guns used in fighter aircraft, are mated with ammunition handling systems that deliver a steady supply of rounds to the gun (each round including a shell and a brass shell casing), remove the spent shell casings from the gun, and store the spent shell casings to preclude their ingestion by the aircraft's engine(s).
FIG. 1
depicts an ammunition handling system used with a high rate of fire gun. A continuous conveyor belt
21
feeds rounds into a storage drum
22
. The rounds leaving the drum are reinserted into the conveyor belt, then fed via a loading sprocket
24
into a gun
26
. Each round includes a shell
27
and a shell casing
28
. An unloading sprocket
30
takes the spent shell casings
28
from the gun
26
. Unloading sprocket
30
rotates within the housing of a transfer unit
31
.
FIG. 2
depicts a conventional unloading sprocket
30
. The sprocket
30
includes a forward sprocket
32
and an aft sprocket
34
. The two sprockets are fixed together by a hub
36
, and therefor rotate in unison.
FIG. 3
broadly depicts the aft end “a” of a shell casing
28
and the forward end “f” of the shell casing.
In normal operation, high rate of fire gun mechanisms are subjected to severe accelerations in multiple directions. When subjected to such accelerations, the forward end “f” of shell casing
28
in the conventional unloading sprocket
30
can become bound between the forward sprocket
32
and a gun guidebar. This interference can result in the forward end “f” of shell casing
28
being dented.
Dented shell casings may be deformed to an extent that is physically incompatible with the high speed mechanisms contained in the ammunication handling system, causing these mechanisms to jam and, in some instances, be damaged as the dented shell casing is processed through them. In an extreme case, this damage may render the gun system inoperable.
SUMMARY OF THE INVENTION
The present invention is directed to an ammunition handling system and a shell casing unloading device used in an ammunition handling system that substantially minimizes one or more of the problems due to the limitations and disadvantages of the related art.
The principal advantage of the present invention is the incorporation of a shell casing unloading device that substantially reduces the number of dented shell casings.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The advantages of the invention will be attained by the apparatus particularly pointed out in the written description and claims below, as well as the attached drawings.
To achieve the advantages of the invention, an ammunition handling system includes a loading sprocket for feeding a round into a gun, the round including a shell and a shell casing, and an unloading device for unloading the shell casing from the gun. The unloading device includes a first rotatable shaft having a first circular gear and a first non-circular gear fixed thereto, the first shaft being drivable by a power source. A second rotatable shaft is provided having a second non-circular gear fixed thereto and engaged with the first non-circular gear, and a first sprocket and first hub fixed thereto to rotate with the second shaft. A second sprocket and second hub nominally aligned with the first sprocket is mounted around a reduced diameter portion of the first hub to be rotatable independently of the second shaft, having a second circular gear engaged to rotate with the first circular gear.
Based on the circular shape of the first and second circular gears, the second sprocket will rotate at a generally constant velocity. However, based on the non-circular shape of the first and second non-circular gears, the second shaft and the first sprocket will rotate at a variable velocity.
The first sprocket is the forward sprocket, handling the forward end “f” of the shell casing, and the second sprocket is the aft sprocket, handling the after end “a” of the shell casing. The variable velocity of the forward sprocket, which includes slowing down below the speed of the aft sprocket then accelerating to catch up with the speed of the aft sprocket, enables the forward end “f” of the shell casing to avoid a random binding condition of the forward end “f” of the shell casing between the guide bar and the forward sprocket, thereby avoiding denting of the forward end “f” of the shell casing.
In another aspect of the invention, the unloading device includes a first rotatable shaft having a first circular gear and a first non-circular gear fixed thereto, the first shaft being drivable by a power source. A second rotatable shaft has a second non-circular gear fixed thereto and engaged with the first non-circular gear, and a first sprocket fixed to the second shaft to rotate therewith. A second circular gear is coupled to a second sprocket, which is provided generally coaxially aligned with the first sprocket, and the second circular gear is engaged with the first circular gear.
It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory, and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 4270436 (1981-06-01), Bishop et al.
patent: 4328737 (1982-05-01), Nelson et al.
patent: 4505181 (1985-03-01), Schneider et al.
patent: 4932307 (1990-06-01), Menges et al.
IDF 20MM Gun System-Lockheed Martin; Nov. 20, 1996.
Engineering Change Proposal for 20MM Gun System: (ECP) No. IDF-5606-0013; Mar. 21, 1997.
Baxter David R.
Derry Bernard A.
Prouix Edward A.
Carone Michael J.
Finnegan Henderson Farabow Garrett & Dunner LLP
General Dynamics Armament Systems
Thomson Michelle
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