U.S. patent number 3,724,326 [Application Number 05/167,208] was granted by the patent office on 1973-04-03 for sub-caliber conversion unit.
Invention is credited to Robert W. Day.
United States Patent |
3,724,326 |
Day |
April 3, 1973 |
SUB-CALIBER CONVERSION UNIT
Abstract
A sub-caliber conversion unit adapted to be detachably secured
to and firmly supported by the lower receiver group of a larger
caliber pistol, wherein the slide in such conversion unit operates
independently of the barrel, and means are provided to permit full
travel of said slide.
Inventors: |
Day; Robert W. (San Antonio,
TX) |
Family
ID: |
22606399 |
Appl.
No.: |
05/167,208 |
Filed: |
July 29, 1971 |
Current U.S.
Class: |
89/196; 42/77;
42/49.02; 42/7 |
Current CPC
Class: |
F41A
21/10 (20130101); F41A 11/02 (20130101) |
Current International
Class: |
F41A
11/00 (20060101); F41A 21/10 (20060101); F41A
21/00 (20060101); F41A 11/02 (20060101); F41d
011/06 (); F41c 021/10 () |
Field of
Search: |
;89/196,163,128
;42/77 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Borchelt; Benjamin A.
Assistant Examiner: Jordan; C. T.
Claims
What is claimed is:
1. In combination with the receiver of a larger caliber pistol
comprising a foremost end portion U-shaped in transverse section,
aligned bores adapted to receive a cross pin, spaced and rearwardly
extending slide rails, and an integrally formed cross member
intermediate said slide rails,
a sub-caliber conversion unit comprising a barrel, slide and recoil
spring means,
said barrel terminating forwardly in a downwardly depending tubular
section and rearwardly in a downwardly depending lug,
horizontal flats laterally of said lug,
said tubular section of said barrel adapted to at least partially
insert into the foremost end of said receiver,
said recoil spring means abutting selected portions of said slide
and said lug,
means in said lug adapted to coact with said cross pin whereby said
flats are pulled downwardly against said slide rails and said lug
is pulled rearwardly against said cross member in said
receiver.
2. The invention of claim 1 including securing means on said
tubular section adapted to pass outwardly of the foremost end
portion of said receiver.
3. The invention of claim 1 wherein said recoil spring means at
least partially extends forwardly into said tubular section in said
barrel whereby a full length recoil spring is utilized.
4. The invention of claim 1 wherein said means comprise a bore in
said lug which is out of alignment relative to the aligned bores in
said receiver whereby upon insertion of said cross pin said flats
are pulled downwardly against said slide rails and said lug is
pulled rearwardly against said cross member in said receiver.
5. The invention of claim 1 wherein said means comprise a
downwardly opening slot in said lug and a spring at least partially
restricting passage of said cross pin whereby upon insertion of
said cross pin said flats are pulled downwardly against said slide
rails and said lug is pulled rearwardly against said cross member
in said receiver.
6. The invention of claim 1 wherein said conversion unit further
includes a breech block detachably secured to a selected portion of
said slide.
7. A firearm comprising a barrel, slide, recoil spring means and
receiver assembly,
said receiver assembly comprising a foremost end portion U-shaped
in transverse section, aligned bores adapted to receive a cross
pin, spaced and rearwardly extending slide rails, and an integrally
formed cross member intermediate said slide rails,
said barrel terminating forwardly in a downwardly depending tubular
section and rearwardly in a downwardly depending lug,
horizontal flats laterally of said lug,
said tubular section of said barrel adapted to at least partially
insert into the foremost end of said receiver assembly,
said recoil spring means at least partially extending into said
tubular section of said barrel and abutting selected portions of
said slide and said lug,
means in said lug adapted to coact with said cross pin whereby said
flats are pulled downwardly against said slide rails and said lug
is pulled rearwardly against said cross member in said receiver
assembly.
Description
BACKGROUND OF THE INVENTION
The sub-caliber conversion unit of the subject invention coacts
with the lower receiver group of a larger caliber pistol without
modification or alteration thereto, and the sub-component parts
thereof operate in their normal, intended manner. Such conversion
unit is rapidly and easily secured to or removed from the lower
receiver group. The barrel is supported along its longitudinal axis
by said lower receiver group thereby eliminating the inaccuracies
inherent in prior art conversion units. Means are provided whereby
the recoil spring operates the slide independently of the barrel
and allows full travel of said slide. A coacting sub-caliber
magazine insert, detachably secured in the magazine of the large
caliber pistol, provides sub-caliber cartridges for such
sub-caliber pistol.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a
sub-caliber conversion unit which is rapidly and easily installed
on or removed from the lower receiver group of a large caliber
pistol, wherein no modification of or alteration to said lower
receiver group is required.
Another object is the provision of such a sub-caliber conversion
unit which is firmly supported at several locations along its
longitudinal axis by the lower receiver group.
A still further object is the provision of such a sub-caliber
conversion unit wherein the slide operates independently of the
barrel, and means are provided to permit full travel of said
slide.
A further object is the provision of a sub-caliber conversion unit
adaptable for use with the lower receiver group of a larger caliber
pistol including a sub-caliber magazine insert detachably secured
in the magazine of said larger caliber pistol.
A final object is to provide such a sub-caliber conversion unit
adaptable for use with the lower receiver group of most larger
caliber pistols, without modification, wherein the sub-components
thereof work in their normal, intended manner.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view, partly broken away and partly in
section, of the conversion unit of the subject invention, said
conversion unit is detachably secured to the lower receiver group
of a larger caliber pistol.
FIG. 2 is a vertical sectional view, transverse to the longitudinal
axis, taken along the line 2--2 of FIG. 1, looking in the direction
of the arrows.
FIG. 3 is a vertical sectional view, transverse to the longitudinal
axis, taken along the line 3--3 of FIG. 1, looking in the direction
of the arrows.
FIG. 4 is a fragmentary, side elevational view, partly broken away
and partly in section, of the foremost and medial portions of
sub-caliber conversion unit with a blade sight secured to the
barrel housing, showing the slide secured in retracted
position.
FIG. 5 is a fragmentary, vertical sectional view showing another
means for securing the barrel housing to the foremost end of the
receiver.
FIG. 6 is a fragmentary, plan view taken along the line 6--6 of
FIG. 5, looking in the direction of the arrows.
FIG. 7 is a fragmentary, side elevational view, partly broken away
and partly in section, showing still another means for securing the
barrel housing to the foremost end of the receiver.
FIG. 8 is a vertical sectional view, transverse to the longitudinal
axis, taken along the line 8--8 of FIG. 7, looking in the direction
of the arrows.
FIG. 9 is a fragmentary, side elevational view, partly broken away
and partly in section, showing another means for securing the rear
portion of the barrel housing to the receiver.
FIG. 10 is a vertical sectional view, transverse to the
longitudinal axis, taken slightly rearwardly of the rear face of
the barrel housing, looking in a forward direction.
FIG. 11 is a fragmentary, horizontal sectional view, showing
another means for securing the rear portion of the barrel housing
to the receiver.
FIG. 12 is a fragmentary, side elevational view showing still
another means for securing the rear portion of the barrel housing
to the receiver.
FIG. 13 is a side elevational view, partly broken away and partly
in section, showing the magazine utilized in the larger caliber
pistol with a sub-caliber magazine insert detachably secured
therein, which insert accommodates ammunition for the sub-caliber
pistol.
FIG. 14 is a side elevational view, partly broken away and partly
in section, of the magazine insert.
FIG. 15 is a top plan view of FIG. 14 of the drawings.
Referring now to the drawings, wherein like reference characters
designate like or corresponding parts throughout the several views,
there is shown in FIG. 1 of the drawings an embodiment of the
sub-caliber conversion unit 20 of the blow back type which is
adapted to coact with the lower receiver group 21 of a larger
caliber pistol, such as the Government model Colt 45 caliber
semi-automatic pistol or the like; alternatively, an automatic
pistol may be constructed in accordance with the principles of the
invention. Conversion unit 20, which has the general shape and
dimensions of the corresponding parts of the larger caliber pistol,
comprises barrel housing 22, barrel 23, breech block 24,
reciprocable slide 25, and desirably a sub-caliber magazine insert
26, or separate sub-caliber magazine. Removal of cross pin 27 and
slide stop 28 (see FIG. 4) of the larger caliber pistol permits the
barrel and slide assembly to be removed from the receiver. The
lower receiver group 21 to which conversion unit 20 is detachably
secured by means of cross pin 27 and slide stop 28 comprises the
frame, trigger mechanism, hammer, sear, springs, safeties, stocks,
and magazine of the larger caliber pistol.
In the embodiment of FIG. 1 of the drawings, barrel 23 of any
desired sub-caliber is carried in barrel housing 22. Barrel 23
terminates rearwardly in an integrally formed, angularly downwardly
extending cartridge loading ramp 29 which aids in guiding a
cartridge C into the cartridge chamber. It is understood that the
invention is not to be restricted solely to a barrel housing with a
separate barrel insert but also covers a barrel housing which is
rifled to any desired caliber and further includes an integrally
formed cartridge loading ramp.
Longitudinally extending tubular section 30 is integrally formed on
the foremost end of barrel housing 22 downwardly of barrel 23.
Cylindrical plug 31, adapted to insert into the foremost end of
bore 32 in section 30, may be adjusted in length and/or composition
by the user to provide a desired barrel weight. Vertically
extending female threads 33 in plug 31 accommodate set screw 34 the
remote end of which abuts nylon insert 35 or the like carried in a
communicating bore 36 in barrel housing 22. Insert 35 is adjusted
to bear against the lower surface of barrel 23 by means of set
screw 34 thereby securing plug 31 and also eliminating
manufacturing clearances between the barrel housing and the barrel.
A horizontally extending shoulder 37 (see FIG. 4) which lies in a
plane slightly below the upper limit of bore 32 is provided in each
side of the barrel housing, said shoulder 37 extends into the rear
face of tubular section 30.
Barrel housing 22 terminates rearwardly in an integrally formed and
downwardly depending lug 38; the rear face of the barrel housing,
barrel and lug terminate in the same transverse, vertical plane. A
transversely extending bore 39 in lug 38 accommodates cross pin 27
heretofore mentioned whereby the rear portion of the barrel is
detachably secured to the receiver.
Breech block 24, of any suitable material and preferably of
suitably heat treated steel, is generally U-shaped in elevation,
comprising base 40 with spaced, upstanding fore and aft portions
41-42, respectively. The breech block thus formed is detachably
secured in the rearmost, upper portion of slide 25 by means of
transversely extending pins 43-44 which are passed through bores in
slide 25 and insert into aligned bores in portions 41-42,
respectively. Longitudinally extending bore 45 passes through
portion 41 of the breech block while coaxial bores 46-47 of
progressively greater diameters are provided in aft portion 42.
Firing pin 48 passes through bore 46 and terminates forwardly in a
reduced diametral extension 49 which carries spring 50, said
extension partially inserts into bore 45 and is adapted to strike
cartridge C; the ends of spring 50 abut the rear surface of portion
41 and shoulder 51 of the firing pin maintaining the pin in
normally retracted condition. Rearwardly, firing pin 48 terminates
in transversely extending and spaced collars 52-53 which ride in
bore 47 with pin 44 passing intermediate the said collars thereby
retaining the firing pin in the breech block. A cartridge extractor
54, such as is well-known in the art, is carried in breech block
24; the empty cartridge cases are ejected through port 55 by
striking ejector 56 which may be provided on magazine insert 26,
installed in conversion unit 20, or on lower receiver group 21.
It is to be understood that breech block 24 may be integrally
formed with slide 25; in such modification of the invention pin 43
is not required and the rearmost pin 44 is utilized solely to
retain firing pin 48 in the composite slide-breech block.
As best seen in FIGS. 4 and 10 of the drawings, the lower surface
of barrel housing 22 rearwardly of tubular section 30 is milled or
otherwise removed to provide a generally horizontal flat 57 which
extends along a plane slightly above the upper limit of bore 32 in
tubular section 30, said flat also extends laterally of lug 38. The
lower sides of barrel housing 22 corresponding to flat 57 are
provided with shoulders 58 which parallel and are above the plane
of flat 57; shoulders 58 terminate inwardly in vertically extending
shoulders 59. The interior angle formed between the foremost end of
shoulder 58 and the rear end of tubular section 30 is desirably
radiused, indicated by reference numeral 60, and the exterior angle
formed between the rearmost portion of shoulder 58 and the rear end
of barrel housing 22 is also desirably radiused, indicated by
numeral 61.
Still referring to FIG. 4 of the drawings, slide 25 further
includes integrally formed and forwardly extending sides 62 which
pass laterally of each shoulder 59 on the barrel housing with the
upper edge of each side generally paralleling and spaced slightly
downwardly of the respective shoulder 58; the lower edge of each
side 62 lies in the plane of shoulder 37. Forwardly, an integrally
formed cross member 63 joins the opposing sides; the upper surface
64 of said cross member is approximate medially the upper and lower
edges of sides 62. The innermost surface of each side includes a
longitudinally extending slot 65 which extends forwardly into cross
member 63, forming recess 66 therein. Downwardly depending section
67, integrally formed with cross member 63, is generally U-shaped
in transverse section and is adapted to slidably insert into the
foremost end of the receiver; section 67 includes a longitudinally
extending bore 68 which is coaxial with bore 32 in tubular section
30. The foremost ends of cross member 63 and section 67 are
vertically aligned, and as viewed in FIG. 1 of the drawings, in
loaded and cocked condition, such vertically aligned portions are
spaced slightly rearwardly of the rear end of tubular section
30.
Counterbore 69 in the rear end of section 67 accommodates flange 70
of a forwardly extending, cup-shaped retainer 71, said retainer
includes axial bore 73 in the foremost end thereof. Elongated guide
pin 73 which terminates rearwardly in head 74 carries recoil spring
75; the foremost end of said pin passes through bore 72 with the
ends of spring 75 bearing against the inner surface of retainer 71
and head 74, respectively; the rearmost end of head 74 is placed
against the face of lug 38. The recoil spring and guide thus formed
are free-floating and self-aligning under all conditions. When
slide 25 is in the retracted position, illustrated in FIG. 4 of the
drawings, recoil spring 75 is compressed principally within
retainer 71.
As heretofore mentioned, the foremost end 76 of receiver 77 is
generally U-shaped in transverse section (see FIG. 8), permitting
section 67 of slide 25 which inserts therein to move rearwardly
until the rear end thereof abuts an integrally formed and
transversely extending shoulder 78 in the receiver, said shoulder
is positioned forwardly of bore 79 (see FIG. 10) which accommodates
cross pin 27. Rearwardly of bore 79 the receiver 77 includes an
integrally formed, transversely and vertically extending member 80.
Longitudinally extending and spaced slide rails 81 begin in
proximity to shoulder 78 and extend rearwardly approximately along
the plane of flat 57.
The user inserts the foremost end of rails 81 of the receiver into
the mating and rearwardly opening slots 65 in the slide and
conversion unit 20 is pushed rearwardly. Lug 38 is adapted to pass
intermediate slide rails 81 in a close fit and the upper surface of
said slide rails bear against flats 57 laterally of lug 38.
Simultaneously the foremost end of the receiver passes outwardly of
section 67 of the slide; continued rearward movement of conversion
unit 20 causes tubular section 30 of the barrel housing to insert
in a tight fit into the foremost end 76 of the receiver until
stopped by the rear surface of lug 38 butting the foremost surface
of member 80.
In the preferred embodiment of the invention, barrel housing 22 and
lug 38 are preferably composed of a malleable material, such as
aluminum. Bore 39 in lug 38 is slightly out of alignment with
respect to bore 79 in the receiver; when cross pin 27 is driven
into bore 79, and thence into bore 39, the lug 38 is pulled
downwardly and rearwardly whereby flats 57 laterally of lug 38
firmly seat upon the upper surface of slide rails 81 and the rear
surface of lug 38 bears firmly against the foremost end of member
80 in the receiver.
The foremost end 76 of receiver 77 is secured to tubular section 30
by means of clamp 82 detachably secured at one end to section 30
and adapted to pass downwardly of and support the foremost end of
said receiver.
There is shown in FIGS. 5-6 of the drawings another embodiment of
securing means for the foremost end of the receiver. More
particularly, recess 83 in the lower surface of tubular section 30
accommodates one end of a spring clamp 84 detachably secured
therein by means of screw 85 or other fastening means whereby
spring tension is applied against the foremost end 75 of the
receiver.
In the embodiment of FIGS. 7-8 of the drawings, the rearmost
portions 86 of tubular section 30 extend substantially outwardly of
the corresponding portions of the foremost end 76 of the receiver;
a rearwardly opening, generally U-shaped recess 87 is provided
therein into which the foremost end of the receiver inserts in a
close fit. Set screw 88 or the like passes through section 86 and
is adjusted to bear against end 76, additionally securing the same
in recess 87.
Referring now to FIGS. 9-10 of the drawings, there is shown another
means for securing the rear portion of the barrel housing 22 to the
lower receiver group 21. More specifically, barrel housing 22
terminates rearwardly in a downwardly depending lug 89 the rear end
of which is vertically aligned with the rear end of the barrel
housing. A longitudinally extending slot 90 is provided in the
bottom surface of the lug with a communicating, angularly upwardly
extending slot 91 terminating rearwardly in the face of said lug. A
longitudinally extending bore 92 which is slightly below the plane
of flat 57 communicates rearwardly with slot 91. A transversely
extending recess 93 in lug 89 opens downwardly and terminates
upwardly in the approximate plane of slot 90. One end 94 of a
spring is adapted to insert into bore 92; portion 95 of said spring
lies in slot 91 and extends downwardly through slot 90; terminal
portion 96 of said spring lies in slot 90 forwardly of recess 93
and extends angularly upward. It is to be understood that portions
95,96 of the spring partially restrict passage of cross pin 27
through recess 93. When pin 27 is driven into bore 79 in the
receiver, the foremost end is stopped by said spring. An additional
force causes pin 27 to ride over the lower portions 95,96 thereby
exerting a downward and rearward spring tension on the barrel
housing.
In the embodiment of FIG. 11 of the drawings, lug 97 includes a
transversely extending, tapered bore 98 adapted to receive a
mating, tapered pin 99; said pin is driven through bore 79 in the
receiver, through tapered bore 98, and thence into aligned bore 79
in the opposite side of the receiver. Female threads 100 in the
remote end of pin 99 accommodate screw 101 whereby slide stop 102
is detachably secured thereto.
Referring now to FIG. 12, barrel housing 22 includes an integrally
formed, downwardly depending lug 103; transversely extending slot
104 which preferably opens downwardly communicates with an
angularly upwardly and rearwardly extending slot 105. Drive pin 27
is first passed through aligned bores 79 in the receiver with the
said pin passing through slot 104. A downward force applied to the
rear portion of the barrel housing causes pin 27 to partially ride
up inclined slot 105 securing the barrel housing to the receiver.
To remove barrel housing 22 from the receiver, pin 27 must first be
removed.
A downwardly opening recess 106 (see FIG. 4) is provided in the
outer surface of side 62 adjacent the rear end of slide stop 28
whereby slide 25 may be locked to the rear. Conventional sights 107
are mounted upon the upper surface of the barrel housing 22 or
slide 25.
There is shown in FIGS. 13-15 of the drawings sub-caliber magazine
insert 26 which desirably inserts into a conventional magazine 108
of the larger caliber pistol. Magazine 108 is integrally formed
comprising spaced sides 109-110, rounded front 111, back 112, base
113 and an internal, spring activated follower 114 or the like
whereby cartridges are fed into the cartridge chamber in the
barrel. A rectangularly shaped magazine catch slot 115 is provided
in a uniform, exact location in each such type magazine, normally
in the upper, right-hand side 109 and which in some magazines at
least partially extends into front 111. Magazine insert 26
comprises spaced sides 116-117, front 118 and back 119, which
portions are adapted to pass inwardly of the corresponding members
of the larger caliber magazine 108. Slot 120 (see FIG. 14) is
provided in side 116, said slot terminates upwardly in
perpendicularly extending slot 121 forming an outwardly extending
lip 122 adapted to insert into the rearmost portion of magazine
catch slot 115 in the larger caliber magazine 108. Bracket 123 is
secured at any desired location on back 119 whereby insert 26 is
positioned forwardly in magazine 108.
Follower 124 (see FIG. 15), carried in insert 26, is stopped
upwardly by means of inturned lips 125-126 on the upper end of the
respective sides. Ejector 56 heretofore mentioned preferably
extends perpendicularly upward of lip 126. Downwardly depending lug
127 on follower 124 accommodates one end of spring 128; the lower
end of said spring bears against a L-shaped floor plate 129 which
is maintained in insert 26 by pin 130 bearing against the lower
surface of the said plate and passing through aligned bores (not
shown) in the lower portions of sides 116,117.
The user positions insert 26 upon follower 114 of magazine 108 and
exerts a downward force thereon until lip 122 inserts into the
rearmost portion of slot 115. To remove insert 26 from magazine
108, a pointed tool is inserted in slot 115 thereby depressing lip
122 at which time insert 26 is forceably ejected from the larger
caliber magazine by the spring activated follower 114.
Sub-caliber magazine insert 26 may be loaded or unloaded either
prior to or after insertion in magazine 108. It is to be understood
that the invention is not to be restricted solely to the use of
magazine catch slot 115 but a slot or other opening may also be
provided on any other selected part of the magazine to accommodate
a coacting member, or other securing means may be provided on the
large caliber magazine and the coacting sub-caliber magazine insert
carried therein.
It should be understood, of course, that the foregoing disclosure
relates to only preferred embodiments of the invention and that
numerous modifications or alterations may be made therein without
departing from the spirit and scope of the invention as set forth
in the appended claims.
* * * * *