US3636878A

US3636878A - Safety grenade

Info

Publication number: US3636878A
Application number: US847852A
Authority: US
Inventors: James P Fay
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-08-06
Filing date: 1969-08-06
Publication date: 1972-01-25
Anticipated expiration: 1989-01-25

Abstract

A grenade having control means for arming the grenade in response to a predetermined free flight thereof and for firing an armed grenade in response to interruption of said free flight of the grenade, said control means having a safety time factor for preventing arming of the grenade in response to short periods of free flight. Means can also be provided for preventing unintentional operation of the grenade.

Description

United States Patent Fay [451 Jan. 25, 1972 [54] SAFETY GRENADE 2,996,009 8/l96l Donahue, Jr. et al 102/76 [72] Inventor: James P. Fay, l8 France St., Norwalk, Primary Examiner koben stahl Conn 0685] Attorney-Johnson & Kline [22] Filed: Aug. 6, 1969 [57] ABSTRACT [211 App]. No.: 847,852

A grenade having control means for arming the grenade in response to a predetermined free flight thereof and for firing [52] Cl "102/64, 02/76 an armed grenade in response to interruption of said'free flight [51] I Cl 27/08 of the grenade, said control means having a safety time factor [58] Field ofSearch ..l02/64, 76 for Preveming arming f the grenade in response to she" periods of free flight. Means can also be provided for prevent- [561 Retewnces ing unintentional operation of the grenade.

UNITED STATES PATENTS 1 1 Claims, 1 1 Drawing Figures l,2l6,078 2/1917 Coleman ..l02/76 m II M I56 5&3 49 N PATENTED JANZS 1912 SHEET 1 BF 2 I NVENTOR. James P F Q BY i 197 TOR/V576 PATENTED JANZS r972 SHEET 2 OF 2 INVENTOR f ay 147' 7' ORA/E Y5 Jay/65 SAFETY GRENADE I-Ieretofore, grenades were usually activated by a fuse which was normally ignited by a spring-operated striker and the fuse calibrated to set off the main charge at a predetermined interval of time thereafter. This has several disadvantages. Accidents can occur if a man should drop a grenade so as to accidentally ignite the fuse. Also, there is a danger that if thrown too soon, it can be picked up and thrown back before the fuse sets off the charge. To avoid this, it has been the practice of arming the grenade and holding it for a few seconds so that it will explode before it can be picked up and returned.

The present invention provides a grenade having a novel control for preventing the difficulties heretofore encountered. In carrying out the invention, the grenade is provided with a means for arming the grenade in response to predetermined free flight of the grenade and for firing the armed grenade in response to interruption of said free flight of the grenade.

A feature of the invention resides in the safety construction wherein the grenade is armed only after a predetermined in terval of free flight and should the free flight cease prior to the arming, the control returns to normal position. Thus, if the grenade is dropped and/or accidentally placed in free flight for a short period of time, it will not become armed.

Another feature of the invention resides in the fact that the control means can be rendered inoperative to arm the grenade until a pin or other safety unit has been intentionally removed, thus preventing accidental arming of the grenade during storage or handling.

The control member can be a mechanical control member or an electrical control member and is highly effective in preventing accidental discharge of the grenade.

Other features and advantages of the invention will be apparent form the specification and claims when considered in connection with the accompanying drawings wherein:

FIG. 1 is a sectional view of one form of the invention.

FIG. 2 is a partial view of FIG. 1 with the grenade in armed position.

FIG. 3 is a view similar to FIG. 2 with the grenade in firing position.

FIG. 4 is a fragmentary view showing the dashpot.

FIG. 5 is a view of a safety device for the grenade.

FIG. 6 is a sectional view of another form of the invention.

FIG. 7 is a view of the sear means of FIG. 6.

FIG. 8 is a sectional view of still another form of the invention.

FIG. 9 is a detail of the control member of FIG. 8.

FIG. 10 is a sectional view of a further form of the invention.

FIG. 11 is a view taken along line l1ll of FIG. 10.

FIG. 12 is a sectional view showing a diagrammatic electrical circuit of a still further form of the invention.

As shown in FIG. 1, the grenade has a frangible body 10, preferably metal, filled with a charge of explosive material 11, preferably a powder. A firing and control device comprises a plug 12 threaded into an opening 13 in the body 10 and has a tubular housing 14 threaded on the plug. The housing has a closed end 15 carrying a primer or detonator 16 which is located within the charge of explosive material to fire the charge when actuated. A firing element 17 having a firing pin 17a for actuating the primer is slidably mounted in the housing and is normally urged to firing position by a spring 18 having one end engaging the plug 12 and the other end bearing on a flange 19 on the firing pin. The firing pin is held in retracted position against the urging of spring 18 by a sear member or latch 20 having one end pivoted at 21 on the plug and having a latch element 22 at the other end extending under a shoulder 23 on the firing pin when the latter is in retracted position. When the sear is released by moving the latch element 22 from the shoulder 23, the spring moves the firing element 17 downwardly. The pin 17a, upon impact with the primer 16, will fire the charge and explode the grenade.

The novel control for the sear means operates to arm the grenade in responses to a predetermined free flight and to fire the armed grenade in response to interruption of said free flight thereof.

In the control shown in FIGS. 1-5, a control strand or cord 30 has a weight 31 herein illustrated as a ball secured at one end and disposed in a cavity 32, preferably spherical, formed in a projecting head portion 33 of the plug 12. A tubular pedestal 34 is carried by the plug and projects into the cavity as shown in FIG. 1. The strand passes through the pedestal and is connected to a piston 35 operating in cylinder 36 formed on the plug to form a control dashpot.

The strand is then connected to a sear control or blocking member 37 disposed in a bore 38 in the firing member. It is normally positioned. as shown in FIG. I. In this position it engages the sear 20 and blocks the sear against release of the latch 22 from the shoulder 23 of the firing member. The end of the strand is connected to a light spring 39 which tends to draw the strand downwardly when the device is in free flight so that the ball moves from contact with the wall as shown in FIG. 1 until the ball 31 is seated on the pedestal as shown in FIG. 2.

As the strand moves downwardly under the action of spring 39, it is controlled by the dashpot to provide a timing operation. The strand moves the blocking member 37 past a resilient actuator 40 for the sear to the position shown in FIG. 2 to arm the device.

The dashpot as illustrated in FIG. 4 has a flap valve 41 under the piston normally closing a plurality of ports 42 in the piston to seal the ports resulting in the slow downward movement of the piston. However, when the free flight of the grenade is interrupted, the ball 31 falls off of the pedestal 34 and draws the strand 30 upwardly against spring 39. The strand can move relatively quickly in this direction since the flap valve 41 opens the vent ports 42.

As the strand moves upwardly, the control or blocking member 37 moves upwardly and engages the sear actuator 40 to pivot the sear and retract the latching element 22 from the shoulder 23. The spring 18 immediately drives the firing element 17 downwardly to cause the firing pin 17a to strike the primer 16 and discharge the explosive material.

An advantage of this control resides in the fact that should the grenade be subjected to free flight for a period of time less than that required by the dashpot for arming the grenade, as might be occasioned by handling the grenade or by dropping it to the ground, the ball, upon interruption of said free flight of the grenade, automatically quickly draws the strand upwardly and resets the control means. This provides an important safety factor.

The form of the invention shown in FIGS. 6 and 7 is similar in structure and operation as that of FIG. 1 with the exception of the structure and operation of the sear means. As shown, the sear means comprises an elongate element 120 having one end pivoted on the closed end of the housing 14 at 121. The sear extends upwardly through an aperture in the end of the firing element 117. It has a latch element 122 normally engaging the end of the firing element at 123 and holding the firing element in retracted position against the action of spring 18. The upper end is curved at 111 and has a narrow slot 112 communicating with a large opening 113 (FIG. 7). The upper end extends into the enlarged bore 138 as shown in FIG. 6 and has an anchor 114 for the spring 39.

In operation the control or blocking member 37 is in normally blocking position as shown in FIG. 6. When the grenade is in free flight, the ball 31 is moved to the top of the pedestal by spring 39. The strand 30 moves the blocking member 37 downwardly and it passes through the enlarged opening 113 with the strand passing through slot 112 and thus arming the grenade. Upon interruption of free flight of the armed grenade, the ball 31 leaves the pedestal drawing the strand 30 upwardly. This will move the upper end of the sear means to the right in FIG. 6 and release the latch element 122 from contact with the wall at 123 and permit the spring 13 to move the firing element 117 downwardly and cause the firing pin 1 17a to strike the primer 16 and fire the grenade.

In the form of the invention shown in FIGS. 8 and 9, control is similar to that in FIG. I, with the exception of the sears and sear-actuating means which is as shown in FIG. 9. It comprises block 210 secured to the strand 3% and carrying a pair of spring legs 211, M2 urged to the position of H6. 8. The sears 22% are pivotally carried by the plug 12 and have latches 222 extending under the shoulders 223 on the firing pin, as shown in FIG. 8. In arming the device, when it is in free flight, the spring 39 moves the strand downwardly, removing the blocking element 37 from behind the sears. As the strand moves down, the

legs

211, 212 move inwardly to pass the ends of the sears and then outwardly to extend under the shoulders 220a on the scars. As the free flight is interrupted, the ball falls off the pedestal drawing the strand upwardly. The

legs

211, 212 spread outwardly. This outward movement causes the sears to pivot with their upper ends moving outwardly and removing the latches 222 from shoulders 223 on the firing pin, whereupon spring 13 urges the firing pin to firing position.

In the form of the invention shown in FIGS. and M, the control means is similar to that shown in H6. ll, except that the sears 320 for controlling the firing are arcuate elements 322 cooperating with a V-groove 323 on the end of the firing member 317. The sears are held in place by the ends of resilient arms 3MB extending from a sleeve 311i slidable in bore 338 in the housing part 31% secured to the plug 12. The sleeve 311 has resilient latch fingers 315 engaging shoulders 316 in the housing part 314a which will prevent the sleeve from sliding upward. The latch fingers 315 have hooked members 330 extending upwardly to cooperate with a firing ring 331 carried by the dashpot piston 335. The ring has a cam surface 332 cooperating with the hooked members 330 to retract the latches on the sleeve during the downward movement of the ring with the strand 30 under the urge of spring 39 during free flight of the grenade to free the sleeve. The ring has a free edge 333 to engage the hooks 330 on the sleeve to withdraw the sleeve in an upward direction by the upward movement of the strand 30 upon interruption of the free flight. This causes the resilient arms 31% to be moved from behind the sears. The sears 320 move out of the groove 323 in the firing member 317. This enables the spring 318 to move the firing member 317 into firing position.

If desired, means can be provided to prevent unintentional firing of the device. While this may take many forms, it is herein illustrated as a means applicable to the forms of the invention shown in FIGS. ll, 6, 8 and ll) for preventing movement of the strand 30 until a safety device is removed. As shown in FIG. 5, the head portion 33 of the plug 112 opposite the pedestal 34 has an aperture 45 to receive a hollow pin 46 slidable in the aperture and having an O-ring 17 sealing the aperture. The hollow pin is adapted to slide over the pedestal, as shown in MG. 5, to grip the strand and hold it against accidental movement. The projecting portion of the pin has a ring 48 which may be gripped to withdraw the pin. It is only after the pin is withdrawn that the strand can move to arm the grenade in response to free flight and fire the grenade in response to interruption of said free flight.

The foregoing forms of the invention have mechanically controlled arming and firing means. in the form of the invention shown in FIG. 12 an electrical control means is provided. As shown, the spherical cavity 32 in the head portion 33 of the plug 12 threaded in the body it) is provided with an insulating liner 5% and supports two spaced electrical contacts 5E0, 502. Contact 501 is connected through a normally closed switch 503 to the terminal of a battery 5&4 with the other terminal of the battery being grounded.

A safety pin 503a normally maintains the switch in open position until it is desired to fire the grenade at which time the pin 50311 is withdrawn to permit the normally closed switch to complete the circuit therethrough.

The contact 502 is connected through a lead 505 to a resistor 506 and a capacitor 507 to ground. Also the lead connects through a resistor 593 to a unijunction transistor 5439 and to a firing member or squib 516 to ground. The squib 516 is usually located in the housing M in inner wall E5 in place of the primer l6, and battery, resistors, capacitor and transistor are usually potted into a single unit (not shown) disposed within the housing M.

The liner 500 has a quantity of electrolyte E stored therein and normally out of engagement with the contacts 501. 502 as shown in W6. 12. However, when the grenade is in free flight the electrolyte will move to the dot-and-dash position and will close the circuit between

contacts

501, 502.

With the circuit closed the current will flow through the resistor 506 and charge the capacitor 597 at a predetermined rate and providing the desired time delay for arming the grenade. The current will also flow through resistor 508 to provide a small bias on the transistor 509. When the free flight of the grenade is interrupted, after the grenade has been armed, the electrolyte B will return to normal position and open the circuit. This causes the bias current to become zero whereupon the capacitor discharges through its connection to the transistor 509 to ground and ignites the squib and fires the charge in the grenade.

Variations and modifications may be made within the scope of the invention and portions of the improvements may be used without others.

l claim:

l. A grenade having an explosive charge, means including sear means for firing said charge, and control means for controlling the firing of said charge, including a strand having means thereon for normally maintaining said strand in a retracted position, a blocking means carried by said strand for engaging and preventing actuation of said sear means to fire said charge with said strand in normal position, means for moving said strand from normal position in response to free flight of the grenade for a predetermined time, movement of said strand from said normal position moving the blocking means from said blocking position to an armed position with respect to said sear means, interruption of said free flight causing said strand to be retracted to normal position and causing the armed sear means to be actuated to fire the explosive charge.

2. The invention as defined in claim ll wherein there is a safety means engaging said strand and preventing operation of the control means until the safety means is positively removed.

3. The invention as defined in claim 1 wherein the control means includes time delay action means connected to said strand to prevent arming the device by accidental free flight thereof for a period of time less than the time consumed by the delay action means.

4. The invention as defined in claim 3 wherein the time delay action means comprises a dashpot for slowing the action of the control means from normal condition to am the device, said dashpot having vent means to permit the control means to retum to a normal condition in the event the free flight ceases before the time delay means has completed its function.

5. A grenade device comprising a frangible body, a charge of explosive material within the body, means for firing the charge, and control means for the firing means comprising an actuating element normally held in retracted position, a blocking means normally positioned in blocking relation to said firing means and connected to said actuating element, said blocking means being moved from blocking relation to an anning position in response to predetermined movement of said actuating element from normal position as a result of free flight of the device, said actuating element actuating the armed device for firing the charge on return of the actuating element to said normal position in response to interruption of said free flight of the device.

6. The invention as defined in claim 5 wherein the means for firing the charge includes a spring-urged firing pin and a releasable sear normally holding the firing pin in retracted position and the control means includes a control member for normally preventing release of said sear and movable with respect to said sear to arm the device in response to free flight of the device and for causing the sear to release the firing pin in response to the interruption of said free flight of the device.

7. The invention as defined in claim 5 wherein the control means for firing the charge comprises a plug mounted on said body, a tubular housing on said plug and having a closed inner end with said primer mounted therein to be disposed in said charge, a firing pin movable in the housing and urged to firing position by resilient means, sear means holding said firing pin in retracted position, and means for actuating the sear means comprising a flexible strand having a weight at one end disposed in and resting on the wall of a cavity larger than the weight and formed in said plug, said strand passing through a pedestal projecting into said cavity and connected to a time delay means and to a control element for the sear and having the other end connected to resilient takeup means for the strand whereby upon free flight of the grenade the resilient takeup means draws the flexible strand downwardly as controlled by the time delay means and moves the weight into a position on the pedestal, the movement of the strand enabling the control element to be moved into operating relation to the sear means and upon interruption of the free flight of the grenade the weight moves back to the original position causing retraction of the strand and moving of the control element to release the sear means from the firing element to enable the firing pin to be moved under the urge of resilient means to firing position.

8. The invention as defined in claim 5 wherein the means for firing the charge comprises a tubular housing having a closed inner end with said primer mounted therein to be disposed in said charge, a firing pin slidable in the housing and urged to firing position by resilient means, sear means holding said firing pin in retracted position, and control means including means for actuating the sear means comprising a flexible strand having a weighted ball at one end disposed in and resting on the wall of a large cavity in a spherical chamber connected to said housing, said strand passing through a pedestal projecting into said chamber and connected to a time delay means and to a blocking element for the sear and having the other end connected to resilient takeup means for the strand whereby upon free flight of the grenade the resilient takeup means draws the flexible strand downwardly as controlled by the time delay means and moves the ball into a position on the pedestal, the movement of the strand enabling the blocking element to be moved out of blocking relation to the sear means and upon interruption of the free flight of the grenade the weighted ball moves off of the pedestal and back into engagement with the wall causing retraction of the strand moving of the blocking element to release the sear means to enable the firing pin to move under the urge of resilient means to firing position.

9. The invention as defined in claim 6 wherein the releasable sear is pivoted intermediate its ends and has a shoulder adjacent the upper end for engagement by the control means, and said control member comprises a resilient actuator movable past the shoulder for arming the device and for engaging said shoulder to move the sears to release position during the firing operation.

10. The invention as defined in claim 6 wherein the sears comprise arcuate shoes normally urged by spring fingers carried by a slidable sleeve into engagement with a groove on the firing pin to hold the said pin in retracted position, and said control member having a firing ring interlocking with said sleeve in an arming position and moving said ring and spring fingers to release the sears from holding relation with the firing pin to enable the pin to fire the charge.

1 l. The invention as defined in claim 5 wherein the control means comprises a flexible strand having a weight at one end resting on the wall of a spherical cavity, a tubular pedestal projecting into said cavity and through which the strand passes, a control member carried by the strand and a resilient takeup for the strand to cause the strand to move in one direction and the ball to be seated on the pedestal and the control member arm the device in response to free flight of the grenade, said ball falling from said pedestal upon interruption of said free flight of the grenade and causing the strand to move in the opposite direction causing the control member to actuate means for firing the armed grenade.

STATES PATENT OFFICE UNETED PO-105O Patent No.

Inventor(s) James P. Fay

It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

column 1, line 33 "form" should read from; line 73,

"responses" should read --response--;

column 3, line 60 "510" should read --5o1--;

column 6, line 5 after "strand" --and-- should be inserted.

Signed and sealed this lOth.day of October 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSGHALK Attesting Officer Commissioner of Patents as PATENT OFFICE CQRRECHON STA UNETED S t t n 2 m. e 7 t d t 9 a e u a l m t 2 K P do T 7 L 3 e 9 e 0 f 5 ie 3 s 1 M 2 b 7 n C u i r S r y m e 6 Te r 80 n e b Tn 2 u b m 3 5 .1 m h; u m m as o J w me 3 u R1 bd OS O f E ae rn h o B 6U. f0 1 S.. 00 d h e P m y R C .8 tr .8 a t r e d a no r d .D ic w d w m P: m M e a O Q a rd 6 1 er a T mm mm d "d m E u l n h m x; y 0d u a t a 0a hl o r F r Su h t d rt 0 s S e nb D m n .w u an Ti H F 3 m o r e m w 8 S b? O 1 6 S 9 T1 7 e t fs 5 t r 8 m m n e n f d we a a ee S a. n c i 6 J it 3n 0 a Ci 3 ft 30 6 5 Tf Fu 6 ie P d Ef AM L 8S 6 e 6 L0 3 a me n n n F c 1; l 8 0g \1 a l" l l i S SS S 1 O l 9 J t t N r m l 3 6 3 ms t w Ih Le Ae n n t n A t W t w V d m w mm a n n 1 l l P I a o o o 2 c c

Claims

1. A grenade having an explosive charge, means including sear means for firing said charge, and control means for controlling the firing of said charge, including a strand having means thereon for normally maintaining said strand in a retracted position, a blocking means carried by said strand for engaging and preventing actuation of said sear means to fire said charge with said strand in normal position, means for moving said strand from normal position in response to free flight of the grenade for a predetermined time, movement of said strand from said normal position moving the blocking means from said blocking position to an armed position with respect to said sear means, interruption of said free flight causing said strand to be retracted to normal position and causing the armed sear means to be actuated to fire the explosive charge.

2. The invention as defined in claim 1 wherein there is a safety means engaging said strand and preventing operation of the control means until the safety means is positively removed.

4. The invention as defined in claim 3 wherein the time delay action means comprises a dashpot for slowing the action of the control means from normal condition to arm the device, said dashpot having vent means to permit the control means to return to a normal condition in the event the free flight ceases before the time delay means has completed its function.

5. A grenade device comprising a frangible body, a charge of explosive material within the body, means for firing the charge, and control means for the firing means comprising an actuating element normally held in retracted position, a blocking means normally positioned in blocking relation to said firing means and connected to said actuating element, said blocking means being moved from blocking relation to an arming position in response to predetermined movement of said actuating element from normal position as a result of free flight of the device, said actuating element actuating the armed device for firing the charge on return of the actuating element to said normal position in response to interruption of said free flight of the device.

11. The invention as defined in claim 5 wherein the control means comprises a flexible strand having a weight at one end resting on the wall of a spherical cavity, a tubular pedestal projecting into said cavity and through which the strand passes, a control member carried by the strand and a resilient takeup for the strand to cause the strand to move in one direction and the ball to be seated on the pedestal and the control member arm the device in response to free flight of the grenade, said ball falling from said pedestal upon interruption of said free flight of the grenade and causing the strand to move in the opposite direction causing the control member to actuate means for firing the armed grenade.