US3052187A

US3052187A - Safety device for delayed action fuze

Info

Publication number: US3052187A
Application number: US569400A
Authority: US
Inventors: Herman L Thwaites; Garland H B Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-12-22
Filing date: 1944-12-22
Publication date: 1962-09-04
Anticipated expiration: 1979-09-04

Description

Sept. 4, 1962 H. L. THWAITES ETAL 3,052,187

SAFETY DEVICE FOR DELAYED ACTION FUZE Filed Dec. 22, 1944 Fig. 2. 14 J7 Hernia-n, L. 77Lwaz'1es E] nmm tow G tl'o rump United States Patent 3,052,187 SAFETY DEVICE FOR DELAYED ACTION FUZE Herman L. Thwaites, Clark Township, and Garland H. B. Davis, Elizabeth, N.J., assignors to the United States of America as represented by the Secretary of War Filed Dec. 22, 1944, Ser. No. 569,490 9 Claims. (Cl. 10282) This invention relates to a safety device for a delayed action fuze and more particularly to a safety device capable of self-arming when placed in contact with a liquid.

An object of this invention is to provide a self-arming safety device for a grenade incorporating a time delay fuze such as is described and claimed in the copending application Ser. No. 569,401, filed December 22, 1944, of Herman L. Thwaites and George L. Matheson.

A further object of the invention is to provide a selfarming safety device that will supplement a manually operated safety device to render the time delay fuze safe when the manual safety device has been removed.

Other objects and advantages of the invention will appear from the following description and the accompanying drawings in which:

FIG. 1 is a side view of a grenade incorporating the invention;

FIG. 2 is atop view of a grenade incorporating the invention; and I FIG. 3 is a vertical section taken along the lines 33 of FIG. 2.

Referring to the drawings in detail, the grenade consists of a charge cup 14 threadedly engaged with a fuze case 5 by means of a screw cap 13 and a primer holder 15. The charge cup 14 contains a plurality of TNT pellets 19 having a central hole through which extends a detonator 18. The TNT pellets 19 are spaced from the Side walls and the bottom of the cup 14, and this space is filled with magnesium powder 2% The magnesium powder preferably comprises a mixture of gradient size particles.

Within the fuze case 5 is contained 'a firing pin 11 threadably engaged with a firing pin nut which is urged to the firing position toward a primer 16 by a spring 9. The end of the firing pin 11 opposite the primer 16 is provided with outwardly tapered shoulders abutting against corresponding inwardly tapered shoulders of a split washer 8. The split washer 8 is held in the position shown in the drawing by a retaining ring 6. It will be evident that when the retaining ring 6 is moved upwardly from around the split washer 8, the split washer is caused to separate because of the action of spring 9, and the firing pin 11 is driven against the primer 16.

The retaining ring 6 is secured to the shank of a perforated plunger 2 by means of a brass screw 7. Between the perforated under-shoulder of the plunger 2 and a shoulder of the fuze case 5 are positioned a bakelite washer 4 and two rubber discs 3. The rubber discs 3 are positioned between the Bakelite washed 4 and the perforated shoulder of the plunger 2 so that when the rubber discs swell on immersion in the gasoline or other liquid hydrocarbon they will move the perforated plunger 2 upwardly thus withdrawing the retaining ring 6 from around the split washer 8.

Adjacent the upper portion of the fuze case 5 are provided two holes for receiving a cotter pin and pull ring assembly 1. When the cotter pin is in position, movement of the perforated plunger 2 in an upward direction is prevented. This pull ring and cotter pin assembly 1 therefore provides a manually operable safety to insure against premature firing of the device.

A self-arming safety device is provided which renders the fuze safe after the cotter pin and pull ring assembly have been removed manually. This self-arming safety consists of a rubber disc 17 compressed within the bore of the fuze case 5 at its open end directly above the perforated plunger 2. The rubber disc 17 is sprung into position and serves to hold the perforated plunger 2 firmly in position after the pull ring and cotter pin have been withdrawn. Thus accidental displacement of the perforated plunger 2 and consequent release of the firing pin is prevented so long as the rubber disc 17 remains in place.

When the cotter pin and pull ring assembly 1 has been withdrawn by the operator, the grenade is ready for immediate placement. The grenade is then introduced into a gasoline tank or other receptacle containing gasoline. The gasoline acts upon the rubber disc 17 causing it to swell and then to spring outwardly, thus effectively removing itself from the end of the fuze case 5. At the same time the gasoline will enter through a central hole in the disc 17 and through the holes in the shoulder of the perforated plunger 2 and come in contact with the two rubber discs 3. The automatic removal of the disc 17 in the manner described permits the perforated plunger 2 to be moved upwardly in the fuze case 5 when the rubber discs 3 swell under the action of the gasoline on the rubber.

After a period of from four to eight hours the rubber discs 3 will usually have swollen to such an extent as to push the plunger 2 upwardly a distance sufficient to withdraw the retaining ring from around the split washer 8. The force of the spring 9 urging the firing pin nut 10 and the firing pin 11 in a downward position causes the split washer 8 to be forced into the space left by the retaining ring 6. When this happens, the firing pin is released and the spring 9 forces the firing pin against the primer 16 which sets off the detonator 18 and the TNT charge 19. The resulting explosion bursts the gasoline container and the magnesium particles, ignited by the explosion, set the gasoline on fire.

While the above described invention is particularly useful in destroying a tank containing a liquid hydrocarbon, such as gasoline or the like, it may readily be modified for use in receptacles containing other liquids.

Under such circumstances the disc 17 and the discs 3 acting on the perforated plunger 2 could be made of materials which were capable of swelling in such other liquids as for example in the case of water, gellatin discs could be used.

We claim:

1. In a time delay fuze having a safety device capable of self arming upon contact with a liquid hydrocarbon the combination of a fuze case having a central bore with a cocked firing pin therein, means including a movable plunger within said bore for releasing the cocked firing pin, and means for preventing premature movement of the plunger to release the cocked firing pin, the last mentioned means comprising a rubber disc compressed within the bore at one end adjacent the plunger, said disc being capable of being deformed upon contact with the liquid hydrocarbon thereby automatically disengaging itself from the bore.

2. A delayed action fuze capable of firing when contacted with a liquid hydrocarbon which comprises a fuze case having a central bore having positioned therein a cocked firing pin, a series of discs capable of being deformed upon being contacted with the liquid hydrocarbon, a plunger actuated by the deformation of said discs to release the cocked firing pin, and means to prevent premature movement of the plunger to release the firing pin, said means comprising a disc capable of being deformed upon contact with the liquid hydrocarbon compressed within the bore at the open end thereof adjacent the plunger thereby permitting the disc to disengage itself automatically from said bore when contacted with the liquid hydrocarbon.

3. A delayed action fuze capable of firing when contacted with gasoline which comprises a fuze case having a central bore having positioned therein a cocked firing pin, a series of rubber discs capable of being deformed upon being contacted with the gasoline, a plunger actuated by the deformation of said discs to release the cocked firing pin, and means to prevent premature movement of the plunger to release the firing pin, said means comprising a rubber disc capable of being deformed upon contact with the gasoline compressed within the bore at the open end thereof adjacent the plunger thereby permitting the disc to disengage itself automatically from said bore when contacted with the gasoline.

4. A delayed action fuze capable of firing when contacted for a period of time with gasoline, which comprises a fuze case having a central bore, a cocked firing pin positioned within the bore, a split washer engaging with the firing pin in cocked position, a retaining ring holding the split washer in engagement with the firing pin, a movable plunger connected to the retaining ring, a rubber disc capable of being deformed upon contact with the gasoline, the said disc being positioned within the bore adjacent to the plunger, thereby causing movement of the plunger to release the firing pin when the disc is contacted with the gasoline for a period of time, and means to admit the gasoline to the disc.

5. In an incendiary grenade adapted to be immersed in a body of inflammable liquid hydrocarbon and to ignite and scatter the ignited liquid responsively to detonation of the grenade, the improvement which consists in a delayed action fuze mounted on the grenade, the fuze comprising a casing having a bore extending therethrough and communicating with an exterior end recess on the casing, a normally cocked firing pin mounted in the bore, releasable means operatively connected to the firing pin securing the latter in cocked position, a spring mounted in the bore and connected to the firing pin continuously urging the firing pin towards firing position, a piston mounted in the bore connected to the pin-releasable means and having an enlarged head directed to the said end recess on the casing, a plurality of rubber discs engaging the piston and head thereof, one of the said discs being positioned and frictionally held in the end recess on the casing, additional rubber discs being positioned in the bore beneath the piston head and in engagement therewith, the said rubber discs being gradually and progressively deformable while in contact with the said liquid hydrocarbon, the said casing having liquid passages connecting the end recess with the rubber discs beneath the piston head, the said passages being obstructed by the rubber disc in the end recess until the said disc becomes expelled from the recess responsively to deformation of the disc in contact with the liquid hydrocarbon, the latter then entering the passages and contacting the rubber discs beneath the piston head, progressive deformation of these discs under action of the liquid actuating the piston for operating the releasable means for the pins for enabling the pin to snap from cocked position to firing position under action of the spring responsively to the gradually progressive deformation of the said rubber discs, and additional removable safety means extending into the casing and obstructing the liquid passages until removed, thereby preventing actuation of the firing pin until after removal of the safety means from the casing and expulsion of the rubber disc from the end recess for uncovering the liquid passages for exposing the discs in the bore to the liquid hydrocarbon.

6. In a time delay fuze capable of firing after immersion in a liquid hydrocarbon for a given period of time, the combination of a casing having a bore extending therethrough, a firing pin positioned in the bore, a split washer in the bore adjacent to the firing pin and in engagement therewith for holding the firing pin in cocked position, a retaining ring engaging with the split washer and holding the washer in engagement with the firing pin, a plunger slidably mounted in the bore and opera tively associated with the retaining ring for moving the ring from engagement with the split washer, and a series of rubber discs capable of being deformed when immersed in the liquid hydrocarbon, the said discs being located in the bore in engagement with the plunger, the discs being slowly and progressively deformable under prolonged contact With the liquid hydrocarbon for actuating the plunger after immersion in the liquid hydrocarbon for a given time until the retaining ring becomes removed from the split washer, thereby releasing the firing pin.

7. in a time delay fuze capable of firing after immersion in gasoline for a given period of time, the combination of a housing having a bore therethrough, a firing pin located in the bore, a split washer in the bore and engaging the firing pin for holding the pin in cocked position, a retaining ring engaging the split washer and holding the Washer in engagement with the firing pin, a plunger positioned in the bore connected to the retaining ring for moving the ring from engagement with the split washer, and a series of rubber discs operatively engaging the plunger and being protractedly deformable by the gasoline when immersed in the gasoline for a given time until the retaining ring is separated from the split Washer responsively to deformation of the rubber discs by the gasolines, thereby releasing the firing pin.

8. A delayed action fuze capable of firing when contacted for a period of time with a liquid hydrocarbon, which comprises a fuze case having a central bore, a cocked firing pin positioned within the bore, a split washer in the bore engaging with the firing pin when the pin is in cocked position for securing the pin in the said cocked position, a retaining ring in the bore holding the split Washer in engagement with the firing pin, a movable plunger in the bore and connected to the retaining ring, and a disc capable of being deformed by prolonged contact with the liquid hydrocarbon, the disc being positioned in the bore in engagement with the plunger, thereby causing movement of the plunger to release the firing pin when the disc is contacted with the liquid hydrocarbon.

9. A delayed action fuze capable of firing when contacted over a prolonged period of time with a liquid hydrocarbon, which comprises a fuze case having a central bore, a cocked firing pin positioned within the bore, a split Washer in the bore and engaging with the firing pin when the latter is in cocked position, a retaining ring in the bore engaging the split washer for holding the split Washer in engagement with the firing pin, a movable plunger mounted in the bore and connected to the retaining ring, a resilient disc positioned in the bore and slowly reactive with the liquid hydrocarbon for gradual deformation responsively to prolonged contact with the liquid hydrocarbon, the said disc being positioned in engagement with the plunger, progressive deformation of the disc by prolonged contact with the liquid hydrocarbon causing movement of the plunger to release the firing pin and means to admit the liquid hydrocarbon to the deformable substance.

References Cited in the file of this patent UNITED STATES PATENTS 811,252 Seddon Jan. 30, 1906 1,788,856 Bossone Jan. 13, 1931 FOREIGN PATENTS 116,726 Greece Dec. 24, 1900 75,250 Switzerland Oct. 18, 1916 495,845 France July 12, 1919