U.S. patent application number 15/718081 was filed with the patent office on 2018-08-09 for b.l.t. bolt carrier.
The applicant listed for this patent is Claude A. Durham, III. Invention is credited to Claude A. Durham, III.
Application Number | 20180224227 15/718081 |
Document ID | / |
Family ID | 63037082 |
Filed Date | 2018-08-09 |
United States Patent
Application |
20180224227 |
Kind Code |
A1 |
Durham, III; Claude A. |
August 9, 2018 |
B.L.T. BOLT CARRIER
Abstract
A bolt assembly is provided for a firearm. The bolt assembly
comprises a block adapted to connect to a firearm frame and a bolt
carrier adapted to reciprocate within the frame. The bolt assembly
comprises a support element between the block and the bolt carrier.
The support element is adapted to reciprocate within the frame with
respect to the cap and with respect to the bolt carrier. The first
and second spaced apart parallel rods are connected to the cap and
extending from the cap. The bolt carrier defines a pair of spaced
apart bores receiving the rods. A first spring is interposed
between the block and the support element, a second spring is
received on the first rod, and a third spring is received on the
second rod.
Inventors: |
Durham, III; Claude A.;
(Lakeside, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Durham, III; Claude A. |
Lakeside |
CA |
US |
|
|
Family ID: |
63037082 |
Appl. No.: |
15/718081 |
Filed: |
September 28, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62400826 |
Sep 28, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F41A 3/82 20130101; F41A
3/26 20130101 |
International
Class: |
F41A 3/26 20060101
F41A003/26; F41A 3/82 20060101 F41A003/82 |
Claims
1. A bolt assembly for a firearm comprising: a block adapted to
connect to a firearm frame; a bolt carrier adapted to reciprocate
within the frame; a support element between the block and the bolt
carrier; the support element adapted to reciprocate within the
frame with respect to the cap and with respect to the bolt carrier;
first and second spaced apart parallel rods connected to the cap
and extending from the cap; the bolt carrier defining a pair of
spaced apart bores receiving the rods; a first spring interposed
between the block and the support element; a second spring received
on the first rod; and a third spring received on the second rod.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 62/400,826 filed on Sep. 28, 2016, entitled
"BLT Bolt Carrier" which is hereby incorporated by reference in its
entirety for all that is taught and disclosed therein.
BACKGROUND OF THE INVENTION
[0002] Normal AR15 rifles have an extension tube that extends to
the rear of the upper receiver and contains the recoil spring.
Given the length of the bolt carrier, the recoil spring needs this
length to compress and provide an adequate range of motion of the
bolt carrier. A disadvantage of a standard AR recoil assembly, the
travel of the buffer to the rear of the buffer tube causes the
weapon to have more felt recoil due to more mass at the rear of the
weapon. While fine for rifles with normal shoulder stocks, the
protruding extension tube is a problem for pistol variants of the
AR 15, as well as folding or fully collapsing stocks, which are
incompatible with a fixed extension tube.
[0003] Accordingly, it is desirable to create a shorter bolt
carrier that has a recoil spring capability that operates fully
within the limited length of an AR-15 upper, with no extension
tube. Due to spring resonance of a shorter operating platform, the
BCG weight is operating closer to center axis, and less recoil is
noticed as muzzle flip is reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 shows the B.L.T. Bolt Carrier. The assembly includes
a bolt carrier 1 that has opposed linear bores. A top-hat shaped
center support 4 has parallel protruding guide rods 2 that extend
into the bores so that the center support telescopes with respect
to the bolt carrier. The two bores associated with the rods are
large enough to receive compression coil springs 16 that bias the
center support away from the bolt carrier.
[0005] An end cap 5 is threaded 11 to connect to the lower receiver
(not shown) on existing threads where a stock might normally be
attached, in line with the center of the barrel bore and bolt
carrier. The cap essentially becomes the rear wall of the receiver,
and the fixed frame of reference that the bolt reciprocates with
respect to. A rear spring (coil, compression) 17 is captured
between the center support 4 and the cap. Thus, as the bolt
reciprocates, the main springs 16 and rear spring 17 both compress,
each storing some of the recoil energy for recover for stripping
and chambering the next round. The center support 4 floats between
the bolt carrier and the cap during recoil cycling, at a middle
position between the two.
[0006] If a single rear spring were used (as in a conventional
AR-15), it would have to be much longer, and the "end cap" would
need to be lengthened to become an extension tube. This is partly
due to the need to absorb recoil energy, and partly due to the
length of the fully collapsed spring when the coils are stacked
against each other, a condition normally to be avoided. It is not
possible to extend the rear spring forward into or around the bolt
carrier because of the needed structure and functions of the bolt
carrier. However, the main spring that resides in part within the
bolt carrier bore provides this added spring capability without
lengthening the rear spring undesirably. The three springs are
essentially end to end, and the entire rear spring remains to the
rear of the entire front spring in all conditions. These are
serially connected with the center support gripped or pinched
between them, and each spring has a size and shape based on the
space it has to work within the B.L.T. BCG.
[0007] In this exploded view, the image shows the rear view of the
main spring zero footprint pocket (6), the guide rods (2) that are
attached to the center support (4). The end cap is the end of the
B.L.T. BCG that houses the solid height of the rear spring.
[0008] FIG. 2 shows the installed length with a frontal view
looking to the right side to the rear. The B.L.T. utilizes a
milspec bolt. The bore is milspec diameter (15).
[0009] FIG. 3 shows the installed length with the right side of the
B.L.T. BCG. The guide rod bore hole goes through the entire BCG.
The end cap shows the threads with a 1 3/16''-16 tpi pitch is how
the end cap attaches to the lower receiver.
[0010] FIG. 4 shows the view when the B.L.T. carrier is in
collapsed position from being fired. In this position, the
retention guide rod is showing through the ejection port cutout.
The center support recesses internally into the end cap fully
compressed.
[0011] FIG. 5 shows a top view image looking down on the installed
length, ready to fire. This spring technology has zero footprint
solid height. The main springs recess internally in the carrier.
The rear spring recesses into the end cap.
[0012] The rear spring 17 presses on the rear surface of the flange
of the center support 4, and the main springs press on the front
surface of the flange, guided by the rods.
[0013] FIG. 6 shows the B.L.T. Bolt Carrier. The assembly includes
a bolt carrier 1 that has opposed linear bores. A top-hat shaped
center support 4 has parallel protruding guide rods 2, 3 that
extend into the bores so that the center support telescopes with
respect to the bolt carrier. The retention guide rod 3 has a flared
tip that prevents the center support assembly from falling out of
the bolt carrier. The bore associated with rod 2 is large enough to
receive a compression coil spring 16 (not shown) that biases the
center support away from the bolt carrier.
[0014] An end cap 5 is threaded 11 to connect to the lower receiver
(not shown) on existing threads where a stock might normally be
attached, in line with the center of the barrel bore and bolt
carrier. The cap essentially becomes the rear wall of the receiver,
and the fixed frame of reference that the bolt reciprocates with
respect to. A rear spring (coil, compression) 17 is captured
between the center support 4 and the cap. Thus, as the bolt
reciprocates, the main spring 16 and rear spring 17 both compress,
each storing some of the recoil energy for recovery for stripping
and chambering the next round. The center support 4 floats between
the bolt carrier and the cap during recoil cycling, at a middle
position between the two.
[0015] If a single rear spring were used (as in a conventional
AR-15) it would have to be much longer, and the "end cap" would
need to be lengthened to become an extension tube. This is partly
due to the need to absorb recoil energy, and partly due to the
length of the fully collapsed spring when the coils are stacked
against each other, a condition normally to be avoided. It is not
possible to extend the rear spring forward into or around the bolt
carrier because of the needed structure and functions of the bolt
carrier. However, the main spring that resides in part within the
bolt carrier bore provides this added spring capability without
lengthening the rear spring undesirably. The two springs are
essentially end to end, and entire rear spring remains to the rear
of the entire front spring in all conditions. These are serially
connected with the center support gripped or pinched between them,
and each spring has a size and shape based on the space it has to
work within.
[0016] In this extended position/installed length is a see through
image that shows internal view of the main spring zero footprint
pocket (6), the smooth guide rod (2) that is attached to the center
support (4) by the threaded end (8), the retention guide rod (3)
and the flared tip (7) that is inserted through the carrier from
the front to the center support where it is threaded into the
center support (4), now the carrier (1), main spring (16), guide
rods and center support connected in operational order. The end cap
is the end of the B.L.T. BCG that houses the solid height of the
rear spring.
[0017] FIG. 7 shows installed length showing a frontal view looking
to the right side to the rear. The B.L.T. utilizes a milspec bolt.
The bore is milspec diameter (15), utilizes milspec dust cover
cutout (12)
[0018] FIG. 8 shows installed length showing the right side of the
B.L.T. BCG, the guide rod bore hole goes through the milspec
ejection port cutout. The end cap shows the threads with a 1
3/16''-16 tpi pitch is how the end cap attaches to the lower
receiver
[0019] FIG. 9 shows the B.L.T. carrier is in collapsed position
from being fired. In this position the retention guide rod is
showing through the ejection port cutout. The center support
recesses internally into the end cap.
[0020] FIG. 10 shows a cutaway view from the bottom looking up in
the collapsed position when in recoil from being fired.
[0021] FIG. 11 shows a cutaway view from the top looking down in
the extended install length ready to be fired.
[0022] FIG. 12 shows a top view image looking down on the installed
length, ready to fire. This spring technology with zero footprint
solid height. The main spring on the left side shows how the spring
recesses internally in the carrier. The rear spring recesses into
the end cap.
[0023] The rear spring 17 presses on the rear surface of the flange
of the center support 4, and the main spring presses on the front
surface of the flange, guided by the rod 2.
[0024] FIG. 13 shows the same view as FIG. 12, but in the fully
compressed condition in full recoil. The center support 4 ensures
that if a first one of the springs is fully compressed so that the
coils touch each other, then the other spring will have some
accommodation to limit this "crash" before it can have a harmful
effect.
[0025] FIG. 14 is fully compressed no springs.
[0026] FIG. 15 is a frontal view looking from the left side to the
rear.
[0027] List of the parts:
[0028] 1. B.L.T. (bufferless technology) Bolt Carrier
[0029] 2. Guide Rod Smooth
[0030] 3. Guide Rod Retention
[0031] 4. Center support
[0032] 5. End cap
[0033] 6. Main spring "zero footprint" pocket
[0034] 7. Flared end of retention guide rod
[0035] 8. Threaded guide rod ends
[0036] 9. Standard Cam cutout
[0037] 10. Standard gas key cutout
[0038] 11. End cap threads (standard buffer threads)
[0039] 12. Standard dust cover cutout
[0040] 13. Standard Gas stake bolt holes
[0041] 14. Gas hole
[0042] 15. Milspec B.C.G. bore hole
[0043] 16. Main spring
[0044] 17. Rear spring
* * * * *