U.S. patent number 3,603,577 [Application Number 04/860,284] was granted by the patent office on 1971-09-07 for buffer device with torsion bar actuated brakeshoes.
This patent grant is currently assigned to N/A. Invention is credited to Robert G. DeRaad.
United States Patent |
3,603,577 |
DeRaad |
September 7, 1971 |
BUFFER DEVICE WITH TORSION BAR ACTUATED BRAKESHOES
Abstract
A buffer device includes a piston slidingly disposed in a
cooperating cylinder so as to be displaceable therein by an
energized, reciprocative member. A compression spring and a torsion
bar are energized by the piston during displacement with the
compression spring absorbing sufficient energy from the member to
return it to its normal position, and the torque in the torsion bar
being applied to a pair of brakeshoes carried by the piston so as
to be actuated thereby against the inside of the cylinder to
convert to heat the remaining energy imparted to the piston.
Inventors: |
DeRaad; Robert G. (Garretson,
SD) |
Assignee: |
N/A (N/A)
|
Family
ID: |
25332873 |
Appl.
No.: |
04/860,284 |
Filed: |
September 23, 1969 |
Current U.S.
Class: |
267/151; 188/129;
89/198; 188/271; 267/209 |
Current CPC
Class: |
F16F
7/06 (20130101) |
Current International
Class: |
F16F
7/06 (20060101); F16F 7/00 (20060101); F16f
003/02 () |
Field of
Search: |
;188/129,271,268
;267/9C,151 ;213/22,24,31,32R,37 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Halvosa; George E. A.
Claims
What I claim is:
1. A buffer device for resiliently stopping an energized
reciprocative member at a retracted position and for returning the
member to a normal position comprising a cylinder, an inner surface
of said cylinder, a piston slidingly accommodated in said cylinder
and disposed for displacement by the member when energized, a
coiled compression spring arranged in said cylinder for compression
by said piston when displaced by the energized member to absorb a
sufficient portion of the energy therefrom for returning said
piston to the normal position, a torsion-bar spring arranged to be
twisted by said piston during displacement by the energized member
to absorb a further portion of the energy therein, and a pair of
brakeshoes carried by said piston and disposed for actuation by
said torsion-bar spring when energized against said inner surface
to convert the remaining energy in the member to heat.
2. The buffer device as defined claim 1 and including means for
connecting said torsion-bar spring to said piston for longitudinal
displacement therewith and rotational displacement relative
thereto, and cam means carried by said torsion-bar spring for
actuation thereby when energized against said brakeshoes for
displacement thereof against said inner surface.
3. The buffer device as defined in claim 2 including a pin
extending through said torsion-bar spring, a pair of cam followers
formed by projecting ends of said pin, a cap attached to said
cylinder, and a pair of cam slots formed in said cap for
cooperatively engaging said cam followers, said cam slots being
designed so that said brakeshoes are applied thereby against said
inner surface for frictional contact therewith according to the
displacement of said piston by the energized member.
4. The buffer device as defined in claim 2, wherein said means for
connecting said torsion bar spring to said piston comprises a head
of elliptical configuration mounted on one end of said torsion bar
spring and cooperating surfaces in said piston, and wherein said
cam means on said torsion bar spring comprises a pair of cam lobes
formed by the elliptical configuration of said head and disposed
for camming contact with said brake shoes.
5. The buffer device as defined in claim 2, and including
cooperating cam means attached to said cylinder and to said torsion
bar for converting longitudinal displacement thereof by said piston
to rotational displacement for energizing said torsion bar spring
during displacement thereof by said piston.
6. The buffer device as defined in claim 2, and including a pair of
cam followers extending from said torsion bar, a cap mounted on
said cylinder, and a pair of cam slots formed in said cap for
sliding engagement by said cam followers to translate longitudinal
displacement of said torsion bar to rotational displacement
thereof.
7. The buffer device as defined in claim 6, and including means for
adjustably mounting said cap on said cylinder so as to adjustably
compensate for wear of said brake shoes and of said cam slots.
Description
BACKGROUND OF THE INVENTION
This invention relates to automatic firearms and provides therefor
a buffer device for resiliently stopping a reciprocative member and
returning it to its normal position to complete an operating
cycle.
With most automatic guns, especially those which fire high-velocity
rounds that create considerable recoil reaction, buffer devices are
required for resiliently stopping an energized reciprocative member
without injurious impact and then returning it back to its normal
position. Most of the buffer devices used in firearms convert the
excess energy applied thereto to heat through frictional means with
the degree of frictional conversion being determined by the load
applied to the buffer.
SUMMARY OF THE INVENTION
It is a principal object of this invention to provide, for firearms
having a reciprocative member energized by cartridge discharge
forces, a buffer device for resiliently stopping the member and
returning it to its normal position in which buffer device the
degree of frictional conversion of the energy transfered to the
buffer device by the member is determined by the linear
displacement of the energized member and not by the load applied
thereby to the buffer device.
It is another object of this invention to provide such a buffer
device in which a coiled compression spring is arranged to absorb
sufficient energy from the member during its recoil stroke to
return it to its normal position with the remaining energy in the
member being converted to heat by a pair of brakeshoes which are
carried by the piston and which are actuated radially therein
against the interior surface of an inclosing cylinder by the
torsion-bar spring according to the torque applied thereto.
It is a further object of this invention to provide for such buffer
device actuation by means of a cam follower and cam slot arranged
to energize the torsion bar by applying a torque thereto during
displacement of the member and according to the design of the cam
slot.
Further objects and advantages of the invention will be apparent
from the following specification and the accompanying drawings
which are for the purpose of illustration only.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinally cross sectioned view of the buffer
device with the piston shown in its normal position;
FIG. 2 is a view similar to Fig. l but showing the piston actuated
by the gun member to its retracted position;
FIG. 3 is a view taken along line 3--3 of Fig. 1; and
FIG. 4 is a view taken along line 4--4 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Shown in the FIGS. is a buffer device 12 arranged so as to be acted
upon by a reciprocative gun member 14 which is energized by
cartridge discharge force for longitudinal displacement from a
forward normal position to a rearward retracted position, which is
from left to right in the FIGS. Buffer device 12 functions, as
hereinafter described, to resiliently stop member 14 in its
retracted position by gradually reducing the energy therein to zero
and then returning it to its normal forward position with a reduced
force.
Buffer device 12 includes a cylinder 16 which slidingly
accommodated a piston 18 and the buffer device is positioned so
that the piston is displaceable along the extended axis of movement
of reciprocating member 14. Piston 18 is provided with a shaft 20
which projects coaxially therefrom through a mating hole 22 in a
bearing 24 which is secured to the front end of cylinder 16. The
end of shaft 20 is contactable by member 14 during displacement to
a retracted position, thereby displacing piston 18 rearwardly in
cylinder 16.
The rear end of cylinder 16 is provided with an annular flange 28
which is of T configuration in cross section and includes an
annular inner section 30 that forms an annular shoulder 32 around
the inside of the cylinder and an outer section 34 that projects
outwardly therefrom. A coiled compression spring 36 is disposed
between shoulder 32 and the adjacent end of piston 18 so as to be
compressed thereby, when displaced by member 14 in cylinder 16, to
absorb a portion of the energy in the member.
A cuplike cap 38 is secured to outer section 34 so as to extend
coaxially from cylinder 16 and so as to be rotationally adjustable
relative thereto through the cooperation of a plurality of bolts 40
mounted through mating holes in the outer section and elongated
slots 42 in the cap.
Piston 18 slidingly accommodates a pair of diametrically opposed
brakeshoes 44 which are essentially of sectoral configuration in
cross section, as noted in FIG. 3, and which are disposed in mating
recesses 46 of similar configuration so as to be radially
displaceable therein into and out of contact with inner surface 48
of cylinder 16. Each of the brakeshoes 44 includes a friction unit
50, composed of a suitable composition such as is used in
brakeshoes for automobiles, and a metallic shell 52 therefor which
encases the friction unit except for face 54 thereof which is
contactable with inner surface 48. Face 54 is arcuately formed
according to the same radius as inner surface 48 so as to have full
contact therewith when pressed thereagainst as hereinafter
described.
Shells 52 are each provided with a front surface 56 and a rear
surface 58 which is parallel thereto, and a first wall 60 and a
second wall 62 which are both tapered inwardly and are contactable
with cooperating surfaces 64 and 66 in piston 18 to limit inward
displacement of the brakeshoes relative thereto. Second wall 62, as
shown in FIG. 3, is shorter than first wall 60, for a purpose to be
described hereinafter, and they are connected by a planar base 68.
Because of the difference in the lengths of first wall 60 and
second wall 62, base 68 is angularly disposed relative to an
intersecting diameter of cylinder 16, as shown in FIG. 3,
Brakeshoes are actuated outwardly into frictional contact with
inner surface 48 by means of a cam shaft 70. Such cam shaft 70
includes a head 72 which is mounted to a torsion-bar spring 80 and
is of elliptical configuration to form a pair of diametrically
opposed cam lobes 74 each of which is cammingly contactable with
base 68 of one of the brakeshoes. Head 72 is rotatingly received in
piston 18 by an axial chamber 73, which has communication with
recesses 46 so that cam lobes 74 may extend thereinto for camming
contact with brakeshoes therein, and the head is held against
longitudinal displacement in the piston by contact of the front and
rear sides of the head with surfaces 76 and 78. Head 72 is fixed to
the front end of torsion-bar spring 80 which extends rearwardly
therefrom through compression spring 36 to terminate in cap 38. A
cylindrical support 81, formed on the rear end of torsion-bar
spring 80, is slidingly disposed in cap 38 and a pin 82 extends
diametrically through the support, as shown in FIG. 4, so that the
projection ends form a pair of cam followers 84 which cammingly
engage a pair of cooperating cam slots in the cap. Cam slots 86 are
designed so as to convert longitudinal movement of torsion-bar
spring 80, relative to cap 38, to rotational displacement thereof
so as to bias head 72 in a direction that rotates cam lobes 74
toward first walls 60, which is in the counterclockwise direction
in FIG. 3, to increase the sections of bases 68 along which the cam
lobes are cammingly effective.
When member 14 is energized and driven to its retracted position it
contacts the end of shaft 20 to drive piston 18 rearwardly in
cylinder 16. The displacement of piston 18 compresses spring 36,
which absorbs a portion of the energy imparted to the piston by
member 14, and drives cam shaft 70 rearwardly. As cam shaft 70 is
moved to the rear, followers 84 move along cam slots 86 causing
torsion-bar 80 to be wound and absorb more of the energy imparted
to piston 18 by member 14. This biases head 72 for rotation so that
lobes 74 thereon act against the respective bases 68 of brakeshoes
44 to cam them brakeshoes against inner surface 48 and convert the
remaining energy imparted to piston 18 to heat through the
frictional contact of the shoes with the inner surface. The design
of cam slots 86 determines the pattern of the frictional conversion
of of the remaining energy to heat along the longitudinal
displacement of member 14. Metallic shells 52 facilitate the
sliding contact of brakeshoes 44 with the contact areas of piston
18 and the sliding contact of cam lobes 78 with the respective
bases 68.
When member 14 is stopped at its retracted position it is
immediately returned to its normal position by the energy stored in
spring 36 and buffer device 12 is thereby made ready for its next
cycle. A resilient bumper 88 is installed in the front face of
piston 18 to cushion the impact thereof with bearing 24 when
stopped thereby in its forward position.
Wear of face 54 and cam slots 86 can readily be compensated for by
adjusting the position of cap 38 on cylinder 16, through the
cooperation of bolts 40 with slots 42. Also, by having cap 38, with
its cam slots 86, adjustable the amount of energy to be stored in
torsion bar 80 and applied to brakeshoes 44 can be readily
changed.
I wish it to be understood that I do not desire to be limited to
the exact details of construction shown and described, for obvious
modification will occur to a person skilled in the art.
* * * * *