Improvements in and relating to Percussion Fuses for Projectiles.
Year: 1890

page_text: Date of Application, 7th Jan., 1890-Accepted, 22nd Feb., 1890
COMPLETE SPECIFICATION.
Improvements in and relating to Percussion Fuses for Projectiles.
I, WILLIAM HALE DRIGGS, Lieutenant United States Navy, residing at number
2023 Hillyer Place, in the City of Washington, District of Columbia, United States
of America, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
My invention relates, generally, to fuses for explosive projectiles and, particularly,
to improvements in that class thereof which is known as percussion fuses, in which
the hammers or plungers contained within the stocks or casings thereof have
hitherto, generally, been held in place by frictional spring action or force until
the sudden stoppage of the flight of the projectiles released and permitted them
to move forward and strike against and explode the caps or fulminates, the fire or
sparks therefrom being transmitted to the interiors of said projectiles and causing
explosion of their charges; and it consists of the novel constructions and arrange-
ments or combinations of parts hereinafter fully disclosed in the description, drawing
and claims.
The objects of my invention are, first, to provide percussion fuses with novel and
improved springs by which the hammers or plungers of said fuses are held normally
stationary in their stocks or casings and released during the flight of the projectiles by
centrifugal force; second, to provide percussion fuses with novel and improved
springs by which the peculiarly constructed hammers or plungers of said fuses are
held normally stationary in their stocks or casings, or away from the caps or
fulminates, until they are set free by the expansion of said springs by centrifugal
force, which is due to the rapid twisting or spinning motion of projectiles when
discharged from rifled guns or ordnance, this expansion of the springs permitting
the plungers to move forward and come into contact with and explode the caps or
fulminates when the projectiles come into forcible impact with the resisting objects
or mediums at which they are directed; third, to provide percussion fuses with
novel and improved devices for normally holding their plungers stationary in their
casings, or out of contact with their caps or fulminates so that they will be safe
for handling and transportation or not liable to explosion from ordinary degrees of
concussion; fourth, to provide improvements in percussion fuses which will enable
them to act with equal efficiency when they are placed either in the front or rear
ends of shells or projectiles; fifth, to provide improvements in the parts of fuses
which are capable of being or adapted to be applied to some of the fuses now in
use; and sixth, to provide certain other novel constructions and arrangements or
combinations of parts, as hereinafter fully described and claimed.
These objects are accomplished by the mechanism illustrated in the accompanying
drawing forming part of this specification, and in which―
Figure 1, represents a longitudinal central section of my preferred form of
percussion fuse;
Figure 2, a detail side elevation of the hammer or plunger;
Figure 3, a transverse sectional view of this fuse, the section being taken on the
line, -a, of Figure 1; looking toward the base or rear end of the casing;
Figure 4, a detail, perspective view of the spring used in this fuse;
Figure 5, a longitudinal, central section of a slightly modified form of my
improved fuse, the same being adapted for use in the front end of a shell or
projectile;
Figure 6, a similar view of another modified form of my improved fuse;
Figure 7, a detail, perspective view of the spring employed in connection
therewith

page_text: Figure 8, a sectional view and side elevation of a modified form of safety pin or
plate for this form of fuse;
Figure 9, a transverse, sectional view of the plunger, the section being taken on the
line, 2, of Figure 6, looking toward the rear end thereof, and―
Figure 10, an inner face view of one of the halves of the two-part plunger.
In the drawing the numeral, 1, indicates the stock or casing of the fuse, which is
screw-threaded along its rear portion, 2, and closed at its rear end by a solid base-
piece, 3, from which projects the annular rib or flange, 4; also, in the rear surface of
this base-piece is formed a square or other polygonally-shaped recess, 5, into which a
wrench-pin or other suitable instrument of corresponding shape is to be introduced
for inserting said stock or casing into and removing the same from the rear end of
the projectile, which, as usual, is formed with a screw-threaded opening.
The front end of the stock or casing of the fuse is open and formed with screw-
threads, 6, for receiving and removably retaining the correspondingly screw-threaded
anvil, 7, as usual, which as shown, is also formed with a square or similarly shaped
recess, 5, in its front or outer face for receiving a wrench-pin or similar device for
operating said anvil and conveniently securing the same to and removing it from the
front end of said stock or casing. If desired, the rear end of the stock or casing and
the front end of the anvil may be cut away or made to form polygonally-shaped
surfaces for the application of suitable wrenches, as usual, for the same purposes.
The inner face of the anvil is formed with a screw-threaded, central, circular
recess, 8, which communicates with a small duct, 9, leading out through the front
face of said anvil, all for the purposes hereinafter stated.
Within the stock or casing is arranged the hammer or plunger, 10, which, as
shown in Figures 1 and 2, is formed cylindrical in shape and of reduced diameter
along its rear portion, where it is provided with an annular groove, 11, and also, with
an annular flange, 12, which normally rests against the rear wall of the opening in
said casing. In the periphery of this plunger, at directly opposite points, are formed
longitudinal rearwardly-convergent grooves, 13, and its front end is provided with
one or more contact-points, 14, the purposes and functions of these features being
hereinafter fully explained.
To the inner face of the anvil, 7, the plunger holding and releasing spring, 15, is
secured in any suitable manner. As shown in Figures 1 and 4, this spring is provided
at its front end with an annular plate or disk, 16, which is formed with a central
opening, 17, and with a central, forwardly-projecting, tubular neck, 18, which is
exteriorily screw-threaded, secured in the correspondingly screw-threaded recess, 8,
formed in the inner face of the anvil, and adapted to hold the cap, or fulminate, 19, in
place after it has been inserted in said recess. From directly opposite points of the
periphery of the disk, 16, extend two elastic or spring fingers, 20, which project
rearwardly and slightly converge toward each other along their rear portion. At
their rear or free ends these spring-fingers are provided with the enlarged and curved
flanges, 21, which are heavier than the body portions of said spring-fingers and extend
at right angles thereto. The object of making these curved flanges of greater relative
thickness and weight than the body portions of said spring-fingers is that, when they
are under the influence of centrifugal force, due to the rapid whirling or spinning
motion of the projectile during its flight from a rifled piece of ordnance, they will
more readily move outward from the annular groove, 11, and straighten said spring-
fingers in the side grooves, 13, of the plunger and thus permit the latter to move
forward and by means of the contact point or points, 14, explode the cap or fulminate
when the projectile comes into contact with an opposing medium. The object I have
in view in using one or more of these contact points is to provide for the employment
of either center or rim fire-caps or fulminates.
It will be obvious that this form of my improved percussion fuse, constructed as
shown and described, will be entirely free from accidental explosion, both before and
after its application to a projectile, as the plunger 10, is normally held securely away
from the cap, 19, by the curved flanges, 21, of the spring-fingers resting within the
annular groove, 11, at the rear end of said plunger; that the spring-fingers, 20, fit

page_text: snugly within the grooves, 13, in the opposite sides of said plunger, prevent the same
from revolving independently of the casing and guide the same and its contact point
or points 14, when released directly forward against said cap; that said plunger is
set free or released to move forward by the expansion of the spring-fingers to points
on a direct line with the inner surface of the casing, this expansion being effected by
the centrifugal force imparted to said spring-fingers through the rapid whirling or
spinning motion imparted to the projectile by its discharge from a rifled piece of
ordnance; that the plunger, after having been released by the centrifugal force
imparted to the spring-fingers and their heavy, curved flanges, does not move forward
to strike and explode the cap until the advancing projectile comes into contact with
an opposing medium or object, and that, as soon as the contact point or points of the
plunger strike the cap, the fire or sparks therefrom will pass through the small duct
in the center of the anvil, ignite the charge contained in the shell or projectile and
explode the latter.
In Figure 5, of the drawing is illustrated an embodiment of my invention which is
applicable to percussion fuses designed to be employed in the front ends or points of
projectiles. In this construction of my invention the rear portion, 2, of the stock or
casing, 1, is made plain and formed in its rear end with the central recess, 5, while
the forward portion thereof, 22, is screw-threaded and provided with the annular
flange, 12; also the opening at the front end of said casing is screw-threaded, for a
short distance rearward, for the purpose of receiving and holding the correspondingly
screw-threaded anvil, 7, which is made solid and formed with the square or similarly
shaped recess, 5, in its outer or front face, for the purpose hereinbefore explained. In
this modification of my invention the inner face of the anvil is formed with a trans-
verse groove, 23, within which is fitted and suitably secured the transverse portion of
the plunger holding and releasing spring, 15, the rearwardly extending fingers, 20, and
the curved flanges, 21, thereof operating to normally hold the plunger, 10, stationary,
but to quickly release the same on the occurrence of centrifugal force, as also herein-
before explained. The outer or front face of this plunger is formed with the central,
circular recess, 8, for receiving the cap or fulminate, 19; also communicating with
this recess is the small, central duct, 9, which extends entirely through the rear
portion of said plunger, registers with the recess, 5, in the rear end of the casing and
conveys the fire or sparks from the cap or fulminate to the explosive charge within
the projectile. In this form of my invention 1 preferably employ a rim-fire cap or
fulminate, and for this reason two contact-points, 14, are arranged opposite the closed
end of the rim of said cap and are preferably formed as parts of the transverse portion
of the spring, 15, but, as is obvious, a single contact-point is all that need be used
for center-fire caps.
In Figure 6, of the drawing, is illustrated another embodiment or modification of
my invention, in which the principle or mode of operation is the same as that incident
to the forms of fuses shown in Figures 1 and 2, and in which the casing, 1, the anvil, 7,
and the plunger, 10, are arranged in the same inanner as in the preferred form of my
fuse, shown in Figure 1, but in which there are the following differences in the
construction of the parts forming the same.
The plunger is of the shape of a truncated cone and has its smaller end projecting
rearwardly and normally supported against the solid base, 3, of the casing. It is
formed in two parts and provided at its front end with the two-part contact-point, 14,
and with the longitudinal grooves, 13, at opposite points in its periphery. Inter-
mediate the two parts of this plunger is arranged the peculiarly shaped spring, 15, as
shown in Figures 6 and 7, having the rearwardly extending fingers, 20, and the heavy,
curved flanges, 21, which are fitted in correspondingly-shaped grooves, 21', as shown
in Figures 9 and 10, formed in the inner faces of the two parts of said plunger. Over
the edges of these grooves, for a portion of their length, project the flanges, 21",
operate to hold the spring-fingers, 20, slightly loose within said grooves, so as to permit
them to move back and forth therein, to a limited extent, and to bend slightly at their
point of junction. This plunger is normally held from forward movement by a bolt
which

page_text: or pin, 24, provided with a screw-threaded shank, 25, which is secured in a corre-
sponding hole formed in the base-piece, 3, of the casing, and with a conically-shaped,
barbed head, 26, at its front end, which fits in a space of the same shape between the
curved flanges of the spring-fingers. Interiorly of the casing, near its front end, is
formed an annular ledge, 27, against which is placed the disk, 16, having the central
opening, 17, leading to the circular recess, 8, in the inner face of the anvil, which
contains the cap or fulminate, 19, and communicates with the small duct, 9, leading to the
interior of the projectile. The disk, 16, is held rigidly in place against the ledge, 27,
by the anvil, 7, when the latter is fully screwed into the front end of the casing. The
opening, 17, with which this disk is formed has its surrounding wall slightly inwardly-
dished, as at, 28, for conforming to the shape of the cap or. fulminate, 19, and firmly
holding the same in place. This disk is also formed or provided with rearwardly
extending arms or guides, 29, which are arranged to fit within the grooves, 13, in the
periphery of the two-part plunger and thus cause the same to positively rotate with
the casing during the flight of the projectile, in the same manner as when the spring-
fingers are fitted within said grooves, as in the other forms of my invention; however, I
only employ these ribs or guides 29, when the conical, barb-headed pin, 26, is used
for normally securing the two-part plunger to the casing, as I sometimes prefer to
dispense with them and, also, with said conical, barb-headed pin, and employ in lieu
of the latter a barbed, knife-edged plate, 30, of the form shown in transverse section
and in side elevation in Figure 8, of the drawing, and which may be provided with
either a polygonal or screw-threaded shank, 25, for securing it to the base-piece of the
casing. Under the employment of this plate, the proximate surfaces of the two-part
plunger are placed over its barbed, knife edge, which will cause said plunger to
positively rotate with the casing, the same as when the guides or spring-fingers are
employed. In this manner, whether the barbed pin or the barbed plate be employed,
the two-part plunger will be compelled to rotate with the casing and projectile, and,
as it does the centrifugal force will cause the spring-fingers to expand and release said
plunger then, the moment the projectile strikes the opposing object, the plunger will
fly suddenly forward and cause its two-part contact-pin to explode the cap or fulminate
and, also, the charge within the shell or projectile, in the same manner in which the
same results are effected in the other forms of my invention.
I am aware that percussion fuses exist in which the plungers are normally held by
the frictional contact of springs and spring-fingers, but they are not safe form handling
or transportation, as they are liable to explosion and damage from ordinary degrees
of concussion; but I am not aware that, prior to my invention, plungers have ever
been held by springs or spring-fingers which were capable of being expanded and
released from said plungers by centrifugal force.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is―
1. In a percussion fuse, the combination, with a casing and a plunger, of a spring
which is constructed and adapted to expand and release said plunger by the action
of centrifugal force, substantially as described.
2. In a percussion fuse, the combination, with a casing and a plunger, of a
spring which is constructed and arranged to normally hold said plunger at or near
its rear end and to expand and release the same by the action of centrifugal force,
substantially as described.
3. In a percussion fuse, the combination, with a casing and a movable plunger
formed with longitudinal peripheral grooves, of a spring which is constructed and
adapted to expand and release said plunger by the action of centrifugal force,
substantially as described.
4. In a percussion fuse, the combination, with a casing and a movable plunger
formed with longitudinal peripheral grooves, of a stationary spring which is
constructed and adapted to expand and release said plunger by the action of
centrifugal force, substantially as described.

page_text: 5. In a percussion fuse, the combination, with a casing and a movable plunger-
formed with longitudinal peripheral grooves, an anvil, a cap or fulminate, one or more
contact-points for exploding the same, and means for conveying the fire from said
cap or fulminate to the charge within a shell or projectile, of a spring which is
constructed and adapted to expand and release said plunger by the action of centrifugal
force, substantially as described.
6. In a percussion fuse, the combination, with a casing and a movable plunger
formed with longitudinal, peripheral grooves, of a spring provided with rearwardly
projecting fingers which are constructed and adapted to expand and release said
plunger by the action of centrifugal force, substantially as described.
7. In a percussion fuse, the combination, with a casing and a movable plunger
formed with longitudinal, peripheral grooves, of a spring provided with rearwardly--
projecting fingers which are constructed and arranged to normally hold said plunger
at or near its rear end and to expand and release the same by the action of
centrifugal force, substantially as described.
8. In a percussion fuse, the combination, with a casing and a movable planger
formed with longitudinal, peripheral grooves, of a spring provided with rearwardly--
projecting fingers having heavy, curved flanges and constructed and arranged to
normally hold said plunger at or near its rear end to expand and release the same
by the action of centrifugal force, substantially as described.
9. In a percussion fuse, the combination, with a casing and an anvil, the former
being formed with a polygonal recess in its rear face and the latter with a recess
of the same shape in its front face, substantially as and for the purpose described.
10. In a percussion fuse, the combination, with a casing and an anvil containing a
cap or fulminate, of a plunger having a contact-point and a spring provided with
rearwardly-projecting fingers which are constructed and arranged to normally hold
said plunger at or near its rear end and to expand and release the same by the action
of centrifugal force, substantially as described.
11. In a percussion fuse, the combination, with the casing, the anvil and the spring-
fingers secured thereto, of the plunger, held between said spring-fingers and formed
with longitudinal grooves and, also, with an annular groove at or near its rear end,.
.substantially as described.
12. In a percussion fuse, the combination, with the casing, the anvil formed with a
central, circular recess and a small duct communicating therewith, the cap or
fulminate in said recess, and the plunger provided with a contact-point, with
longitudinal grooves and with an annular groove at or near its rear end, of the
spring-fingers extending into said grooves and constructed and arranged to normally
hold said plunger stationary and to expand and release the same by the action of
centrifugal force, substantially as described.
13. In a percussion fuse, the combination, with the casing, the anvil formed with a
central, circular recess and a small duct communicating therewith, the cap located in
said recess, and the spring secured to said anvil and provided with rearwardly-
extending fingers having heavy, curved flanges at their rear ends, of the plunger
formed with a contact-point on its front end, with longitudinal grooves and with an
annular groove at or near its rear end in which said curved flanges of the spring-
fingers engage and hold said plunger normally stationary and which are adapted to
expand and release said plunger by the action of centrifugal force, substantially as
described.
14. In a percussion fuse, the combination, with the casing, the plunger formed with
a contact-point at its front end, with an annular groove at or near its rear end and
with longitudinal grooves in its periphery, and an anvil secured to said casing and
formed with a circular recess and a small duct communicating therewith, and a cap or
fulminate arranged within said recess, of a centrally-open disk secured to said anvil
and provided with a central, tubular neck fitting within the recess of said anvil and
with rearwardly-projecting spring-fingers arranged within the longitudinal and
annular grooves of said plunger and holding the same normally stationary and which

page_text: are adapted to expand and release said plunger by the action of centrifugal force,
substantially as described.
15. In a percussion fuse, the combination, with the casing, the plunger formed with
a contact-point at its front end, with an annular groove at or near its rear end and
with rearwardly-converging, longitudinal grooves in its periphery, and an anvil
secured to said casing and formed with a circular recess and a small duct com-
municating therewith, and a cap or fulminate arranged within said recess, of a
centrally-open disk secured to said anvil and provided with a central, tubular neck
fitting within the recess of said anvil and with rearwardly-projecting spring-fingers
arranged within the longitudinal and annular grooves of said plunger and having
heavy, curved flanges at their rear ends for holding said plunger normally stationary
and which are adapted to expand and release the same by the action of centrifugal
force, substantially as described.
16. In a percussion fuse, the combination, with the casing, the plunger formed with a
contact-point at its front end, with an annular groove at or near its rear end and with
rearwardly-converging, longitudinal grooves in its periphery, and an anvil secured to
said casing and formed with a central, screw-threaded recess and a small duct
communicating therewith, and a cap or fulminate arranged within said recess, of a
centrally-open disk provided with a screw-threaded neck fitting within said recess and
with rearwardly-projecting spring-fingers having heavy, curved flanges, which are
respectively arranged within the longitudinal, rearwardly-converging and annular
grooves of said plunger and which are adapted for holding said plunger normally
stationary and to expand and release the same by the action of centrifugal force,
substantially as described.
17. In a percussion fuse, a spring composed of a centrally-open disk provided with
rearwardly extending fingers having heavy, curved flanges at their rear ends,
substantially as and for the purpose described.
Dated this 7th day of January 1800
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.