Jan. 21, 1958 R. H.

PARK 2,820,411
SPONSIVE MAGNETO GENERATOR

-?
 United States Patent Office 2,820,411
Patented Jan. 21, 1958
2
comes better understood by reference to the following de
tailed description when considered in connection with the
2,820,411 accompanying drawings wherein:
Fig. 1 is a sectional view of the nose portion of a bomb
NERTIA RESPONSIVE MAGNETO GENERATOR and illustrating a fuze including the magneto generator
Robert H. Park, Hartford, Conn. of the present invention;
Fig. 2 is a plan view of the magneto generator pef se;
Application October 7, 1948, Serial No. 53,321 Fig. 3 is a sectional view taken along line 3-3 of Fig.
2; and
3 Claims, (Cl. 102-70.2) 0. Fig. 4 is a view in diagrammatic form of an electrical
(Granted under Title 35, U.S. Code (1952), sec. 266) firing circuit for the bomb of Fig. 1 and using the mag
neto generator of the present invention.
Referring more particularly to the drawings in which
The present invention relates to magneto generators and 15 views,numerals
like indicate like parts throughout the several
10 indicates generally a bomb having a casing 11
more particularly to a new and improved inertia respon
sive magneto generator particularly well suited for use isanda afuze main charge 12. Secured in the nose of casing 11
13 having contained therein a detonator 14 and
with ordnance devices operable upon impact or sudden a booster charge 15.
changes in acceleration or deceleration. A magneto generator indicated generally at 16 is posi
Inertia responsive magneto generators heretofore de tioned within fuze 13. Magneto generator 16 comprises
vised generally have taken the form of an initially closed a cylindrical housing of ferromagnetic material indicated
magnetic circuit for a voltage generating coil in which the generally at 17. A permanent magnet 18 is centrally
magnetic circuit includes an inertia responsive element disposed within the housing 17 and is secured to the end
and a permanent magnet which in some cases is also en wall 19 thereof as by a screw 21. The end wall 19 is
ployed as the inertia responsive element. 25 secured to one end of the cylindrical portion 22 of hous
In certain of the prior art generators such, for example, ing 17 by screws 23. Cylindrical portion 22 has an in
as that disclosed in the patent to Edmund L. Zalinski for turned flange 24 at the opposite end thereof.
Magneto-Electric Fuse, No. 384,662, the generating coil Permanent magnet 18 has a flanged spool-shaped core
is arranged to link all of the flux lines of the initially closed 25 fastened to its end opposite to the wall 19. Core 25
magnetic circuit such that upon movement of the inertia 30 has wound thereon a generator coil 26 having conductors
responsive element out of the magnetic circuit, the flux 27
linkages of the coil with the magnetic circuit are suddenly An and 28 leading therefrom to the electric detonator 14.
annular air gap 29 is defined between the flange of
decreased whereupon a voltage is induced in the coil. cylindrical portion 22 and one of the flanges of core 25.
Applicant has found that the output of the voltage gen An annular armature ring 31 of ferromagnetic material
erating coil may be greatly increased by arranging the 35 is normally positioned in air gap 29, thereby to com
inertia responsive element initially in a closed magnetic plete or substantially close a first magnetic circuit or flux
circuit unlinked with the coil so that the flux linkages with path for permanent magnet 18, the first flux path thereof
the coil are suddenly greatly increased from substantially being indicated by dash lines at 32, and to shunt the por
zero as the inertia element moves to open the circuit, the tion of a second magnetic circuit or flux path for the
flux lines being transferred to a second magnetic circuit in 40 magnet indicated by the dashed lines 44. It will be under
cluding an air path traversing the coil as the element stood that the air gap is no larger than necessary to pro
OWes.
vide free movement of the ring in the gap thereby to avoid
An object of the present invention is to provide a new leakage of the flux and resultant linkage thereof with the
and improved inertia responsive magneto generator for coil. Secured to armature ring 29 by screws 33 is an
firing ordnance devices. annular inertia member 34 of non-magnetic material
Another object is to provide an inertia responsive mag such, for example, as brass, member 34 being arranged
neto generator of this character which is self-contained for free movement within housnig 7 in the direction of
and therefore is not dependent for its operation on dry end wall 19.
cells, storage batteries or the like, and is compact thereby The electrical diagram of Fig. 4 illustrates a simplified
requiring a minimum of space for installation. 50 arrangement of an electrical firing circuit for use with
A further object is to provide an inertia responsive the magneto generator of the present invention. The
magneto generator for the firing circuit of an ordnance de generator coil 26 is connected to one side of detonator
vice in which the magnetic flux is transferred from a first 14 by conductor 27. The other end of coil 26 is con
path comprising a closed magnetic circuit having no flux
linkage with the voltage generating coil to a second path 55 nected by conductor 28 to wiper contact 35 which nor
mally bears against insulating sleeve 36 of movable switch
in which the magnetic flux traverses the coil whereby the conductor member 37. On the other side of sleeve 36 a
flux in the path is substantially linked therewith. wiper contact 38 bears thereagainst. Conductor 39 con
A still further object is to provide an inertia responsive nects contact 38 with the other side of detonator 14.
magneto generator for the firing circuit of an ordnance Switch member 37 is threadedly engaged with screw-shaft
device in which the linkage of the voltage generating coil 60 41, the shaft being rotated by an impeller 42 as the bomb
with the magnetic flux of the magneto generator is effected 10 falls from a launching aircraft. In order to provide a
by the movement of an inertia responsive element out of a sufficient time delay before arming the circuit a reduc
closed magnetic circuit for the flux, thereby producing an tion gear 43 may be interposed between shaft 41 and im
induced current output from the coil of sufficient ampli peller 42.
tude to operate the firing circuit. 65 In the operation of the device, it is, of course, apparent
A still further object is to provide electrical firing ap that the circuit, as illustrated in Fig. 4 is in an open or
paratus for ordnance devices which is highly effective for unarmed condition before the bomb leaves the aircraft.
the purpose intended, durable, efficient and simple in op peller It is also apparent that as the shaft 41 is rotated by im
eration, and economical to manufacture. 42 as the bomb falls through the air, the mov
Other objects and many of the attendant advantages of O position able conductor member 37 moves to its circuit closing
this invention will be readily appreciated as the same be wherein it bridges the gap between contacts 38
and 35 and thereby arms the circuit, **
 3. 4
As the bomb strikes the surface of the water, inertia spool-shaped member whereby a firing voltage is induced
element 34 is suddenly moved forward in response to in the firing circuit as the armature is suddenly moved
the set forward force due to the impact, thereby with out of the magnetic circuit upon impact of the ordnance
drawing armature 31 from air gap 29. When this occurs, device with its target.
the flux in the magnetic circuit initially closed by the 2. An inertia responsive magnet generator comprising,
armature, moves to a second path bridging air gap 29 in in combination, a cup-shaped ferromagnetic member hav
a predetermined manner effective to traverse coil 26 in ing an inturned flange on the lip portion thereof, a cylin
- sufficient quantity to induce in the coil a current suffi drical permanent magnet, secured on one end thereof, to
cient to fire detonator 14 thereby to fire; the bomb. the bottom portion of said cup member centrally thereof
A particular advantage of the arrangement of the pres O and terminating at the other, end flush with the inner
ent invention results from the positioning of the coil 26 surface of said flange, a spool-shaped ferromagnetic core
in such a manner that with the armature 31 in the closed member secured to said other end of the said magnet co
magnetic circuit position, there is substantially no flux axially therewith thereby to define an annular air gap
linkage between the coil and the magnetic circuit; whereas between said flange and the inner flange portion of the
when the armature is moved from the initial or closed core member, a coil wound about said core member, an
circuit position, a substantial portion of the flux lines are annular ferromagnetic member disposed in said air gap
caused to follow a new path or circuit traversing coil 26. thereby to shunt the magnetic flux of said magnet where
Thus, the coil produces a large voltage, output by reason by Substantially none of said flux, threads through said
of the sudden change from zero flux linkage to a sub coil until said annular member is moved out of the air
stantial linkage with the magnetic circuit. 20 gap, and a non-magnetic inertia responsive member loosely
Obviously many modifications and variations of the sleeved about said magnet and secured to said annular
present invention are possible in the light of the above member for suddenly, withdrawing the annular member
teachings. It is therefore to be understood that within from the air gap as inertia forces are applied to the mag
: the scope of the appended claims the invention may be neto generator thereby to generate a voltage in said coil
practiced otherwise than as specifically described. 25 proportional to the rate. of change of flux linkages of the
The invention described herein may be manufactured coil with the flux of the magnet.
and used by or for the Government of the United States 3. An inertia responsive magnet generator comprising,
of America for governmental purposes without the pay in combination, a ferromagnetic member, a permanent
ment of any royalties thereon or therefor. magnet, means for securing said magnet at one end there
What is claimed as new and desired to be secured by 30 of to said ferromagnetic member, a core member secured
Letters Patent of the United States is: to said magnet at the opposite end thereof, a coil wound
1. An inertia controlled magneto generator for the on said core-member, said magnet and said ferromagnetic
firing circuit of an ordnance device comprising, incom member defining an air gap, a movable ferromagnetic
bination, a ferromagnetic housing of hollow cylindrical member initially mounted in and substantially filling said
formation one end thereof being closed the other end air gap thereby, to shunt, the magnetic flux of said magnet
being open and having an inturned flange, a cylindrical from said coil, and means for moving said movable mem
permanent magnet axially aligned within said housing ber out of said air gap whereby the flux of said magnet
and secured at one end to the closed end of the hous is caused to flow through said coil thus generating a volt
sing, a flange spool-shaped member of ferromagnetic ma 40 age in said coil.
terial mounted on the other end of said magnet, an arma References Cited in the file of this patent
ture ring of ferromagnetic material normally positioned
between one of the flanges of the spool-shaped member UNITED STATES PATENTS
and the inturned flange of the housing thereby to close 384,662 Zalinski --------------- June 19, 1888
the magentic circuit from the magnet through the hous 2,404,553 Wales ------------------ July 23, 1946
ing, an inertia ring of non-magnetic material secured to
the armature ring and positioned for free movement with FOREIGN PATENTS
in the housing axially of the magnet, and an induction 506,280 France ------------------ May 26, 1920
525,333 Great Britain ----------- Aug. 27, 1940
coil arranged in said firing circuit and wound on the .