Rotary ammunition magazine and follower
View Patent ↗A rotary ammunition magazine for a rifle has a follower that is spring biased and rotates about an axis to move cartridges for feeding to the rifle's chamber. The follower has a surface portion which engages the last cartridge in the stack. The surface portion has one or more characteristics including a transverse orientation angle, a longitudinal orientation angle and an arcuate shape which determine the direction of the force vector and the lengthwise load distribution on the cartridge.
1. A follower for advancing cartridges in an ammunition magazine, said follower comprising:
a plate having a surface positionable within said magazine facing one of said cartridges, said plate having an axis of rotation oriented parallel to said one cartridge;
a bearing mounted on said plate, said bearing comprising at least one lug, said at least one lug defining a bore coaxially aligned with said axis of rotation of said plate;
said surface comprising a surface portion projecting outwardly from said plate, said surface portion being engageable with said one cartridge, said surface portion being angularly oriented relatively to said plate at a transverse orientation angle measured about said axis of rotation.
2. A follower according to claim 1 , wherein said surface portion is arcuate and subtends an angle measured about an axis of curvature oriented transversely to said axis of rotation.
3. The follower according to claim 2 , wherein said surface portion is angularly oriented relatively to said plate at a longitudinal orientation angle measured about an axis oriented transversely to said axis of rotation.
4. The follower according to claim 1 , wherein said surface portion is angularly oriented relatively to said plate at a longitudinal orientation angle measured about an axis oriented transversely to said axis of rotation.
5. The follower according to claim 1 , wherein said bearing comprises first and second lugs, said first and second lugs defining respective first and second bores coaxially aligned with said axis of rotation of said plate.
6. A magazine for holding a plurality of ammunition cartridges, said magazine comprising:
a plurality of sidewalls defining a space for receiving said cartridges;
an elongate opening defined between a first and a second of said sidewalls providing access to said space;
a follower mounted within said space, said follower being rotatable about an axis of rotation oriented parallel to said cartridges for urging said cartridges toward said opening, said follower comprising:
a plate having a surface positioned facing one of said cartridges;
a shaft mounted within said space, said shaft being coaxial with said axis of rotation, said plate being mounted on said shaft;
said surface comprising a surface portion projecting outwardly from said plate, said surface portion being engageable with said one cartridge, said surface portion being angularly oriented relatively to said plate at a transverse orientation angle measured about said axis of rotation a spring biasing said plate for rotation about said axis of rotation.
7. The magazine according to claim 6 , wherein said surface portion is arcuate and subtends an angle measured about an axis of curvature oriented transversely to said axis of rotation.
8. The magazine according to claim 7 , wherein said surface portion is angularly oriented relatively to said plate at a longitudinal orientation angle measured about an axis oriented transversely to said axis of rotation.
9. The magazine according to claim 6 , wherein said surface portion is angularly oriented relatively to said plate at a longitudinal orientation angle measured about an axis oriented transversely to said axis of rotation.
10. The magazine according to claim 6 , further comprising a bearing mounted on said plate, said bearing engaging said shaft.
11. The magazine according to claim 10 , wherein said bearing comprises at least one lug mounted on said plate, said at least one lug defining a bore receiving said shaft.
12. The magazine according to claim 10 , wherein said bearing comprises first and second lugs attached to said plate, said first and second lugs defining respective first and second bores receiving said shaft.
13. The magazine according to claim 6 , wherein one end of said shaft is supported on a third one of said sidewalls and an opposite end of said shaft is supported on a fourth one of said sidewalls, said third and fourth sidewalls being at opposite ends of said magazine.
14. The magazine according to claim 6 , wherein said spring comprises a coil spring acting between said plate and one of said sidewalls.