Elastomeric extractor member
View Patent ↗A biasing member for a bolt assembly of a firearm is described herein. The biasing member comprises a body having a first portion configured to engage and seat within a biasing member receiving indentation of an arm of the extractor, and a second portion configured to engage and seat within a receiving area along a bolt of the firearm. The body provides a biasing force directed against the extractor arm. The body comprises an elastomeric material, and is configured such that the first and second portions provide varying levels of compression sufficient to maintain a substantially constant extractor tension between the extractor arm and a cartridge.
1. A bolt assembly for a firearm, comprising:
a bolt;
an extractor arm pivotally mounted in the bolt having a biasing member receiving indentation formed thereon; and
a biasing member in mechanical communication with the extractor arm and the bolt so as to provide a biasing force against the extractor arm, the biasing member comprising a compressible body having a first cylindrical portion engaged with the biasing member receiving indentation of the extractor arm and having a first diameter and a second cylindrical portion received along the bolt and having a second diameter greater than the first diameter, wherein the body consists essentially of an elastomeric material and is configured to maintain a substantially constant extractor tension between the extractor arm and a cartridge engaged by the bolt assembly.
2. The bolt assembly of claim 1 , wherein the extractor arm comprises a first end, a second end opposite the first end, and a pivoting region arranged between the first end and the second end, wherein the extractor arm is configured to pivot on the pivoting region against the bolt.
3. The bolt assembly of claim 2 , wherein the extractor arm comprises a claw shaped portion proximate its first end.
4. The bolt assembly of claim 3 , wherein the biasing member receiving indentation is proximate the second end.
5. The bolt assembly of claim 1 , wherein the elastomeric material comprises elastomeric polymer units containing silicone, fluorosilicone, or fluorocarbon.
6. The bolt assembly of claim 1 , wherein the elastomeric material comprises elastomeric polymer units having the formula:
wherein R is selected from the group consisting of CH 3 , F, CF 3 , and CH 2 CF 2 CF 3 .
7. The bolt assembly of claim 1 , wherein the elastomeric material comprises elastomeric polymer units having the formula:
wherein R is selected from the group consisting of F and CF 3 .
8. The bolt assembly of claim 1 , wherein the elastomeric material comprises elastomeric polymer units containing thermoplastic or thermoset elastomers.
9. The bolt assembly of claim 1 , wherein the body of the biasing member further comprises a first convex distal end adjacent the first cylindrical portion configured to engage the biasing member receiving indentation and a second convex distal end adjacent the second cylindrical portion configured to engage the bolt.
10. The bolt assembly of claim 1 , further comprising an annular flange between the first and second cylindrical portions configured to be supported by an annular surface about the biasing member receiving indentation.