U.S. patent number 3,603,259 [Application Number 04/740,304] was granted by the patent office on 1971-09-07 for fuze setback and angular acceleration detent.
This patent grant is currently assigned to Avco Corporation. Invention is credited to George Webb.
United States Patent |
3,603,259 |
Webb |
September 7, 1971 |
FUZE SETBACK AND ANGULAR ACCELERATION DETENT
Abstract
A safety fuse is shown incorporated in rocket propelled round of
ammunition. Two complementary mechanisms act upon a slider to
maintain it in a position wherein a primer charge therein is out of
register with a firing pin. When the round of ammunition is
discharged from a gun, linear and angular acceleration are
effective on a locking ball to overcome the action of a spring and
disengage the ball to overcome the action of a spring and disengage
the ball from a notch in the slider's guideway. Angular
acceleration of the round causes the ball to roll into a laterally
extending position in the slider. After discharge from the gun,
centrifugal force disengages two plungers from the slider
permitting it to travel laterally bringing the primer charge into
register with the firing pin.
Inventors: |
Webb; George (Richmond,
IN) |
Assignee: |
Avco Corporation (Richmond,
IN)
|
Family
ID: |
24975932 |
Appl.
No.: |
04/740,304 |
Filed: |
June 26, 1968 |
Current U.S.
Class: |
102/235 |
Current CPC
Class: |
F42C
15/26 (20130101); F42C 15/22 (20130101); F42C
15/184 (20130101) |
Current International
Class: |
F42C
15/184 (20060101); F42C 15/00 (20060101); F42C
15/22 (20060101); F42C 15/26 (20060101); F42c
015/26 () |
Field of
Search: |
;102/79,80,72,78 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Borchelt; Benjamin A.
Assistant Examiner: Devitt, Jr.; Jerald J.
Claims
Having thus described the invention what is claimed as novel and
desired to be secured by Letters Patent of the United States
is:
1. A fuze for incorporation in a round of ammunition which will be
linearly and angularly accelerated, relative to a central spin
axis, when discharged from a gun, said fuze comprising:
a slider;
housing means including a guideway receiving said slider for
movement in a path transverse to said spin axis;
a primer charge;
an igniting means;
means for lockin said slider in a "safe" position preventing
operative contact between the igniting means and the primer
charge;
said locking mean comprising:
a locking element partially engaging said slider and said housing
means and maintaining the slider in said "safe" position;
a reversely folded leaf spring anchored in said slider, effective
on said locking element in the same direction as the round of
ammunition is to be linearly accelerated, for maintaining the
locking element in its locking position;
said slider having a passageway transverse to said guideway and
receiving said locking element when the locking element is
displaced from its locking position against the action of said
resilient means, upon linear acceleration of said ammunition
round;
whereby the locking element will only be displaced from its locking
position by a predetermined linear acceleration and only maintained
so displaced in said slider passageway by angular acceleration,
thereby permitting movement of the slider from its "safe" position
only under conditions encountered in discharge of the round of
ammunition from a gun.
2. A fuze as in claim 1 wherein the locking element is a ball.
3. A fuze as in claim 1 wherein:
the slider has a greater mass on one side of the spin axis,
whereby when the locking element is displaced from its locking
position the slider may be displaced by centrifugal force from its
"safe" position to a position permitting operative contact between
the igniting means and the primer charge.
4. A fuze as claim 1 further comprising:
a plunger; and
resilient means urging said plunger radially inwardly, relative to
said spin axis, against the side of said slider in said "safe"
position,
thereby providing additional means for retaining said slider in its
"safe" position, which means will be released only upon a spin rate
producing a predetermined centrifugal force.
5. A fuze as in claim 2 further comprising:
a pair of plungers;
resilient means respective urging said plungers radially inwardly,
relative to said spin axis, against opposite sides of said slider
in said "safe" position;
thereby providing additional means for retaining the slider in its
"safe" position, which means will not be released upon a radial
loading in only one direction relative to said spin axis.
6. A fuze as in claim 5 wherein the resilient means acting upon the
locking element comprise:
a reversely folded leaf spring anchored in said slider; and
the slider has a greater mass on one side of the spin axis;
whereby when the locking element is displaced from its locking
position and the plungers are displaced from retaining contact with
said slider, the slider may be displaced, by centrifugal force from
its "safe" position to a position permitting operative contact
between the igniting means and the primer charge and wherein said
locking element now locks said slider in the armed position.
Description
The present invention relates to improvements in safety fuzes for
ammunition.
Safety fuzes for ammunition have attained a high degree of
reliability in preventing inadvertant detonation. This is
particularly true of known fuzes which comprise a pair of spring
loaded plungers that maintain a slider in a "safe" position. When a
predetermined spin rate is attained, centrifugal forces cause the
plungers to release the slider allowing it to travel to an "armed"
position in which a primer charge is brought into register with the
firing pin of the fuze. The firing pin will then impinge the primer
charge to detonate the ammunition, upon impact with a target.
One object of the present invention is to provide a complementary
mechanism, compatible with the above-described type of safety,
which will be responsive to other than centrifugal force and
prevent inadvertant arming of a fuze in the remote and unlikely
event the spring loaded plungers are inoperative for that
purpose.
In its broader aspects, the invention has for its object, the
provision of a simple inexpensive and highly reliable safety
mechanism for preventing inadvertant arming of fuzes employed to
detonate ammunition.
These ends are attained in a fuze construction wherein a locking
element is resiliently maintained in a locking position to prevent
lateral movement of a slider from a "safe" position in which
operative contact between a firing pin and primer charge is
prevented. The locking element, preferably in the form of a ball,
is displaced from its locking position by linear acceleration and
maintained so displaced by rotational acceleration of the round of
ammunition in which the fuze is incorporated.
While the described safety mechanism can be used independently it
cooperates uniquely in a construction wherein spring loaded
plungers also prevent movement of the slider from its "safe"
position until a predetermined rate of spin has been imparted to
the round of ammunition as evidenced by the centrifugal force
required to disengage the locking plungers.
The above and other related objects and features of the invention
will be more fully apparent from a reading of the following
description of the accompanying drawing and the novelty thereof
pointed out in the appended claims.
In the drawing:
FIG. 1 illustrates a round of ammunition in which a fuze of the
present invention is embodied;
FIG. 2 is a longitudinal section, on an enlarged scale, through the
fuze identified in FIG. 1;
FIG. 3 is a section taken on line III--III in FIG. 2, illustrating
the "safe" position of the fuze;
FIG. 4 is a section taken on line III--III in FIG. 2, illustrating
the "armed" position of the fuze;
FIG. 5 is a section taken on line V--V in FIG. 3; and
FIG. 6 is a section taken on line VI-VI in FIG. 3.
While the present invention may be employed in fuzes, for a wide
variety of ammunition, certain aspects are particularly applicable
to the type of ammunition illustrated by the round 10 and seen in
FIG. 1. The round 10 comprises an igniter 12, a rocket motor 14, a
fuze 16, a warhead 18 and a ogival cap 20.
Such a round is fired from a rifled barrel by igniting a prime in
the igniter 12 to initiate combustion of a solid propellant in the
rocket motor 14. The gases generated in this fashion accelerate the
round through the barrel as an initial spin is imparted to it by
the rifling of the barrel. After discharge from the barrel the
round is further accelerated by the rocket motor and additional
spin is imparted to the round of discharge of hot gases through
tangential spin ports 22. Thereafter, the fuze 16 detonates the
warhead 18 upon impact with the target.
The fuze 16, now to be described, provides two complementary
mechanisms for preventing inadvertent detonation of the warhead.
Referencing FIGS. 2 and 3, the fuze 16 comprises a container 24
having a flange 26 which is spun inwardly to retain a body member
28. The safety and firing elements of the fuze are contained within
the chamber formed by the container 24 and body member 28.
A slider 30 is retained in a symmetrical radial slot 32, formed in
the body member 28 by a plate 33. The slider carries a primer
charge 34 which in the "safe" position of the fuze, is maintained
out of register with the path of travel of a firing pin 36. The
slider 30 is held in this "safe" position by a pair of locking
plungers 38 which are respectively urged into notches 40, on
opposite sides of the slider by springs 42.
A slot 44 is formed in one side of the slider 30 and receives a
ball 46. A leaf spring 48 maintains the ball 46 in a recess 50
(FIGS. 5 and 6) formed in the body member 28. The spring 48 is of
simple construction having one bent end 52 positioned by a hole in
the slider 30 with its other end 54, being reversely folded within
a slider slot 56 to overlie the ball 46. The ball 46 thus provides
a second means for preventing inadvertent displacement of the
slider 30 to its "armed" position.
A second ball 58 is carried within a slot 60, formed in a slider
30, opposite the slot 44. The purpose of this second ball will be
described later.
The firing pin 36 is mounted on a weight 62 and is biased from the
slider 30 by a spring 64. The firing pin 36 travels in a generally
axially direction, passing through an opening 66 in the retaining
plate 33. A recess 68 in the slider 30 is registered with the
firing pin 36 in the safe position of the fuze. The firing pin thus
will not be damaged in the event it is thrown forwardly during
handling or otherwise when the slider 30 is in its "safe"
position.
In normal use the round of ammunition 10 would be loaded into a gun
barrel with the fuze 16 in its described "safe" position. Upon
firing of the igniter 12, the round will be accelerated both
linearly and angularly as it is discharged along the gun barrel.
The linear acceleration of the round will cause the ball 46 to
deflect the free end 54 of the leaf spring 48 as the ball 46 is
moved out of the body member recess 50. The angular acceleration of
the round will cause the ball 46 to then roll within the slot in or
passageway 44 toward the sidewall of the slot 32. As this occurs,
the free end 54 of the leaf spring 48 will return toward its
original position preventing the ball 46 from reentering the recess
50. The described movement of the ball 46 is best shown by the
phantom line positions in FIG. 6.
In the environment of a rocket powered ammunition round, it is
preferred that the described release of the safety provided by ball
46 occur within the limits of the rounds travel through the gun
barrel.
After discharge from the barrel the round is further accelerated
both linearly and angularly by the rocket motor. When the resultant
centrifugal forces reach a predetermined level, the spring forces
on locking plungers 38 are overcome and then they are withdrawn
from the notches 40. The slider 30 has a greater mass at its upper
end so that, it will be displaced by centrifugal force to the
"armed" position of FIG. 4 once the plungers 38 have been so
withdrawn. The balls 46, 58 are thrown by centrifugal force, into
notches 70, formed in the sidewalls of slot 32, to lock the slider
30 in this armed position.
When the round 10 hits its target, the firing pin will be thrown
forward to strike the primer charge 34, thus providing a high
energy discharge which passes through an explosion 72 in the body
member 28 to detonate the warhead 18.
The described safety action of the ball 46 is particularly suited
to use in combination with a safety of the type provided by the
plungers 38 in that it imposes a maximum number of force loadings
which must be imposed in a proscribed sequence before the fuze is
armed. Such loadings and sequence are virtually impossible to
obtain except in actual firing of a round of ammunition. Therefore,
an ultimate measure of safety is provided.
While it is extremely unlikely, if the locking plungers 38 failed
to perform their safety function, the ball 46 would be capable of
providing a fully adequate measure of safety. Thus it will be
apparent that the described safety functions of the ball 46 will be
adequate, per se, for the requirements of many types of
ammunition.
In this connection it should be noted that the ball must be
subjected to both linear and angular acceleration before it can be
displaced to permit arming of the fuze. Not only is it unlikely
that both such forces would occur in ordinary handling of
ammunition or even accidental mishandling, it is further unlikely
that they would occur with a magnitude comparable to those
generated in the discharge of ammunition. Beyond this the linear
force to displace the ball 46 may be in an opposite direction, as
described, to that required to cause the firing pin to impact the
primer charge. With this in mind it could be advantageous to have
the leaf spring return the ball 46 into the locking recess 50 if
there is not sufficient centrifugal force, in addition to linear
and acceleration, to arm the fuze.
This and other modifications of the described and preferred
embodiment of the invention will occur to those skilled in the art
within this scope of the inventive concepts which are delineated by
the following claims.
* * * * *