US2375627A - Firing mechanism - Google Patents

Description

y 1945- c. v, CROCKETT, JR ET AL 2,375,627 v v FIRING MECHANISM Filed March 8, 1943 5 Sheets-Sheet l Snnmtors attorneys May 8, 19455.

c. v. CROCKETT, JR, ET AL FIRING MECHANISM 3 She etsL-Sheet 2 Filed March s, 1945 y c. v. CROCKETT, JR, ET AL 2,375,627

FIRING MECHAN ISM Filed March 8, 1943 3 Sheets-Sheet 5 W mm a 7 Inventors Patented May 8, 1945 UNITED STATES. PATENT OFFICE. Y

FIRAIN G MECHANISM Clarence V; Crockett, Jr., Birmingham, and

Ghristiaan H. Bouvy, Detroit, Mich, assignorsto General Motors-Corporation, Detroit, Mich a corporation of Delaware- Application March'S, 1943, Serial No. 4781372 7 Claims. ('01. 89-28) This invention relates to gun firing mechanism. Its development arises from the desire to provide electrical firing for a howitzer which originally was designed for lanyard firing. In such gun the usual firing mechanism is of the double action type in which pull of the trigger on thegun first retracts and then releases the firing pin. A variable effort of from about twenty pounds up to a maximum of about sixty-five pounds is required through a travel of about two and one-half inches, The amount of power required to operate the trigger on the howiter is greater than can be developed by any reasonable size electrical solenoid yet electrical firing is desired in conformity with usual tank and gun carriage practice.

An object of the invention is to provide firing mechanism under control of a relatively small solenoid, which can be easily and quickly applied to existing howitzer structure and adopted for I immediate use in gun carriage and tank installations.

A further object of the invention is to provide for trigger actuation by the electrical energization of a solenoid which merely operates a latch and releases a powerful force previously stored as an incident to gun recoil action.

Another object is to take advantage of the howitzer travel in return to its in battery position to put energy into a spring, this energy later being utilized to pull the trigger in the howitzer breech. Another object is to provide for automatic restoration of the latching mechanism after the gun has been fired and before howitzer return motion again stores energy in the trigger actuating spring.

Other objects and advantages will become apparent in the course of the following specification having reference to the accompanying drawings wherein Figure 1 is a top plan view of a portion of a howitzer to which the invention has been applied; Figure 2 is a side elevation looking in the direction of the arrows on line 22 of Figure 1 showing the trigger actuating parts in cocked position; Figure 3 is a fragmentary view of the parts shown in Figure 2 at the limit of released position; Figure 4 is a detail sectional view on a large scale taken on line 4-4 of Figure 1 and Figure 5 is an enlarged sectional view on line 55 of Figure 2.

With the exception of Figure 3 all the views in the drawings illustrate the parts in battery position and locked against firing by means of the hand lever mechanism best shown in Figure 4. This hand lockout will be disregarded in the initial description of the structure and operation.

In the conventional howitzer installation a pair of recoil cylinders ll contain springs, not shown, which act against plungers carried by the breech 2 for the gun barrel 3 and cushion recoil of the gun and urge it toward the left in g ral for holding the gun in battery position. A stationary boss or plate 4 adapted to be secured on a suitable gun carriage and forming part of a fixed cradle mounts the forward extremities .of a pair of upper and lower frames 5' and 6, respectively, each of which consists of a tube formed to generally U-shape outline and projected rearwardly above and below the breech. Welded to the rear of the upper frame 5 is a mounting plate I having bolted on the underside a U-shaped strap 8 to the dependent spaced legs of which are fastened the ends of a forwardly projecting U-shaped bracket 9.

Also mounted inthe dependent legs of the support bracket 8 for rotation is a rockshaft Ill which at its right end has pinned or fixed thereon a lever arm I I connected by a flexible cable or chain I2 with the trigger arm I3 in a movable breech block, Engaged with the trigger actuating lever H is one leg of a torsional coil spring Hi whose opposite end bears against the support bracket 8. The winding of the spring and its action on the rockshaft is such as to. impart a rotating tendency to the rockshaft ill in a clockwise direction as viewed in Figure 2, whereby in the absence of a stronger opposing force the rockshaft will be turned until a lever arm I5 pinned at the opposite or left end of the shaft 10 comes into engagement with one. side of a stop pin indicated at [6. The stop pin l6 also serves as an abutment for the lever l5 to limit its rotation in counterclockwise direction as indicated in Figure 3 of the drawings, when counterclockwise movement occurs to exert pull on the chain {2 for firing the gun. Trigger actuating movement is supplied by force storedin a heavier coil spring H which force in the cockedposition of the parts, predominates thatof the return spring l4. s

A link I8 joins one end of the main spring H to a lever arm 19 pinned or keyed to the rockshaft Ill. The other end of the springll engages a cross bar 20 of a yoke having forwardly projecting pins 2-l2| slidably mounted in the stationary boss 4. Adjustable nuts 22 carried by the pins 21 are engageable with the front face of the boss 4- 1 for limiting rearward. movement of the yoke upon stationary boss 4. This relieves all or nearly all the tension in the spring I! so that the force of the restoring spring M. then takes precedence for returning the rockshaft ID to original position Nowif the rockshaft after return is retained by suitable latch mechanism, the return motion of the gun barrel through the recoil cushioning mechanism brings the abutment ears 23 into engagement with and picks up the spring anchoring yoke to carry it forward and stretch or extend the main spring I! for again storing energy therein for a subsequent firing operation.

To keep the spring I! under tension the rockshaft retainer arm I is arranged to engage at its free end with the end of a latch lever 24 pivotally mounted on the fulcrum pin 25 fixed in the mounting bracket 9 on an axis in spaced parallelism with the axis of the rockshaft. A coiled torsion spring 26 yieldably depresses the latch lever 24 into the path of the rockshaft arm I5 to the limit provided by a stop pin 2! projecting laterally from the bracket 9 into a V-shaped notch at the opposite end of the latch lever 24. This same stop pin 21 extends into a similar notch in a release lever 28 and limits movement thereof.

The release lever 28 is arranged beside the latch 24 and is coaxial therewith on the fulcrum pin 25. A shoulder or ratchet stop formed on the release lever 28 is provided to engage one arm of a pawl or bell crank 29 pivoted on the free end of the latch 24 and provided with a torsion spring 54 which tends to rock the bell crank for releasably maintaining engagement with the stop on the lever 28. Its opposite arm projects downwardly so as to be in the path of return movement, of the rockshaft arm l5 to break the connection between the levers 24 and 28. Thus normally the bell crank 29 servesas a strut to transmit motion from the lever 28 to the latch 24 when the lever is moved in a counterclockwise direction as viewed in Figure 2 for freeing the rockshaft. Then upon return of the rockshaft under its restoring spring l4 and irrespective of the position of the release lever 28 the bell crank or pawl 29 upon being struck by the arm I5 immediately allows the latch 24 to drop into locking engagement with the arm l5 under influence of the spring 26. For restoring the parts after force is solenoid 3! mounted on the frame bracket 9 and having a projectible plunger 32 to engage the lower arm of the release lever 28. Plunger projection upon energization of the solenoid will serve to retract the latch but thereafter as soon as the rockshaft is returned and regardless of continued plunger projection, the latch will return to position for holdin the firing mechanism cocked. Even though the gunners finger is not removed from the solenoid switch button before start of howitzer recovery from recoil, latching of the rockshaft occurs. Thus relatching is independent of solenoid plunger position. As soon as the gunner does release the firing switch button the solenoid circuit is broken to enable plunger retraction and the lever 23 reassumes its original position under tension of the spring 30. Then the bell crank or pawl 29 is forced by its torsional spring into its original position and the gun is again ready to fire.

In case of failure of electr c power or other cause which makes the firing solenoid inoperative,

'hand firing also has been provided. For hand firing purposes the opposite arm of the lever 28 is provided with an elongated slot slidably receiving the pin in a clevis 33, which in the cocked position of the parts is at the front or bottom of the slot in condition to release the latch upon the pull on the rod 34 fixed to the clevis 33. As shown in Figures 1 and 2 the forward end of the pull rod 34 is connected by a clevis 35 to a lever arm 36 on a rockshaft 31 mounted in the stationary boss 4 and provided with a hand crank 38. Rearward pull on the handle 38 will rotate lever 28 in the same direction as it is rotated by the solenoid and actuate the firing mechanism.

Provision is also made for manual cooking of the parts as may become necessary in the case of misfiring or for initially setting up the parts for the first shot. Accordingly a hand crank 39 is mounted on the fulcrum pin 25 and is connected by a link 48 to a lever arm 42 pinned on the rockshaft ID. This lever arm 42 is in the form of a sector having an arcuate slot to which is fitted a pin 43 on the end of the link 40. The hand crank 39 may be moved between the forward limit shown by full lines and the rearward limit shown by dotted lines in Figure 4. In either limit it abuts the supporting parts of the firing mechanism and is releasably retained in either position by being connected to an overcenter coil spring 44, whose point of attachment on the lever carried lateral pin 4| moves above or below center as the case may be and in either position exerts sufficient pull to prevent accidental displacement of the crank.

When the gun is to be fired the hand crank 39 is swung to its rearward or broken line position, wherein the link pin 43 is moved forward in the slot of the sector arm 42. Upon rocking of the shaft NJ to fire the gun the sector arm will be carried forward until the rear end of its slot approaches the broken line position of the pin 43 in Figure 4. Should automatic return of the rockshaft to latched position fail then forward swinging of the hand crank 39 by reason of the engagement of the pin 43 with the rear end of the slot in the sector 42 will return the parts to cocked position. As long as the hand lever is leftin forward full line position, engagement of the pin 43 with the sector will prevent refiring of the gun. It will be noted in Figure 4 that the joint between the lever 39 and the link 40 is above a line which would intersect the pins 43 and 25 and the overcenter relation tends to maintain the parts against breakage of the joint under influence of any force tending to rotate the rockshaft in counterclockwise direction. Thus the hand cocking lever 39 serves the'additional purpose of a safety device to supplement the latch and to prevent rotation of the rockshaft under influence of the main spring I I in the event the latch becomes inoperative or is released accidentally at a time When firing is not desired.

We claim:

1. A gun having a fixed cradle, a barrel mounted on the cradle for recoil movement and firing mechanism including a rockshaft mounted on the cradle for movement between firing and cocked position, a trigger carried with the barrel and operatively connected with the rockshaft, a retainer arm fixed on the rockshaft, a retractible latch member arranged to project into the path of and to block the retainer arm in its cocked position to lock the rockshaft against rotation in gun firing direction, a latch release member positioned adjacent the latch member, a pawl carried by one of the members and releasably engaged with the other member to transmit latch releasing movement therebetween, means on said pawl arranged to be struck by the shaft retainer arm on its return to cocked position and thereby release pawl engagement with said other member, a relatively light spring operatively connected with the rockshaft for urging return of the retainer arm to latch engaging cocked position, a relatively heavy spring operatively connected at one end with the rockshaft for urging the rockshaft to firing position upon latch release and means operatively connecting the opposite end of the last mentioned spring with the barrel so that the spring force decreases below that of the first mentioned .spring upon barrel recoil travel.

2. A gun having a fixed cradle, a barrel mounted on the cradle for recoil movement and firing mechanism therefor including a trigger carried with the barrel, a trigger actuating rockshaft carried by the cradle, a spring operatively connected with the shaft to impart rocking motion to cocked position, a second spring operatively connected with the shaft to rock the same away from cocked position, means operatively connecting the last mentioned spring with the barrel and operative with recoil to decrease the force of the last mentioned spring and enable the first spring to rock the shaft, a latch engageable part on the rockshaft, a spring pressed latch mounted on the cradle and engageable with said part on the rockshaft to lock the rockshaft in cocked position, a release member coacting with said latch and mounted for movement relative thereto, a pawl carried by the latch and engageable with the release member to transmit member movement in one direction to the latch for releasing the rockshaft, said pawl also being engageable with the rockshaft part in its return to cocked position for tripping the pawl from engagement with the release member and insuring latch engagement with the rockshaft part regardless of restoration of said release member.

3. In a gun having a fixed cradle and a barrel mounted on the cradle for recoil action, trigger actuating mechanism including a rockshaft having a lever arm and being mounted on the cradle, a pair of spring elements operatively connected with the rockshaft to exert opposing forces on the rockshaft, means anchoring one of said springs on the gun barrel so that its exerted force is variable and is predominant in gun battery position but is inefiective against the exerted force of the other spring upon recoil action of the gun barrel, a latch positioned adjacent and detachably engageable with said rockshaft arm to retain the same releasably cocked, an electrical solenoid having a plunger, a pawl device interposed between the plunger and the latch to transmit plunger travel to the latch for releasing the rockshaft for its actuation under predominant spring forces, first in trigger actuating direction and then, as a result of gun barrel recoil, in the opposite direction, said pawl being arranged to be struck by the arm of the rockshaft in its return travel and thereby be shifted out of plunger and pawl motion transmitting relation for enabling latch reengagement with said rockshaft arm irrespective of solenoid plunger position.

4. In a gun having a fixed cradle and a barrel mounted on the cradle for recoil travel, firing.

mechanism including a rockshaft mounted on the cradle and rotatable from cocked position to fire the gun, an actuating spring operatively connected at one end with the rockshaft for exerting force to rock said shaft away from cocked position, mean mounting the opposite end-of said spring for movement with gun barrel travel whereby spring force is decreased upon recoil travel, a second spring operatively connected with the rockshaft to return the same to cocked position and a releasable latch to hold the rockshaft on its return to cocked position.

5. In a gun having a fixed cradle and a barre mounted on the cradle for recoil travel, firing mechanism including a rockshaft mounted on the cradle and rotatable from cocked position to fire the gun, an actuating spring operatively connected with the rockshaft for exerting force to rock said shaft away from cocked position, a spring anchoring member carried by the barrel so that spring force decreases upon gun recoil travel, .a second spring operatively connected with the rockshaft to return the same to cocked position, a rockshaft latch, a solenoid having a plunger member operable to move the latch to release position upon solenoid energization, a motion transmitting trip pawl interposed between the latch and said member and means to trip said pawl out of motion transmitting relation to the member and the latch upon return of the rockshaft.

6. In a gun having a fixed cradle and a barrel mounted on the cradle for recoil movement, firing mechanism, including a trigger actuating rockshaft mounted on the cradle, a pair of springs operatively connected with the rockshaft in opposing thrust relation, means joining one of said springs to the barrel for travel with barrel recoil to render its force ineffective against the other spring, a pair of lever arms separately pivotally mounted side by side on a common axis radially spaced from the axis of the rockshaft, a lever carried by the rockshaft and releasably retaining the rockshaft cooked by engagement with the end of one of said pair of lever arms, spring means active on the last mentioned lever arm and yieldably retaining it in latched engagement with the rockshaft lever, a bell crank pivoted on the end of the-last mentioned lever arm, a spring active on the bell crank to urge one crank arm into engagement with a thrust seat on the other lever arm and to project its other crank arm into the return path of the rockshaft lever so as to be struck to free the bell crank from the last mentioned lever arm, a solenoid having a .projectable plunger to strike and swing the last mentioned lever arm upon energization of the solenoid and a spring exerting its force on said lever arms to spread their free ends apart.

'7. Gun firing mechanism including a trigger actuating rockshaft oscillatable from cocked position to firing position and back to cocked position, a lever arm fixed on the rockshaft for swinging to and fro therewith, a spring pressed latch engageable with said arm in its cocked position, a release member pivoted in side by side' coaxial relation with said latch, a trip pawl interposed between the latch and its release member to provide a motion transmitting connection, a part on the pawl projecting into the return path of the rockshaft lever arm to be struck to break said connection, and a solenoid having a plunger engageable with the release member to actuate the same upon electrical energization of the solenoid.

CLARENCE V. CROCKETT, JR.

CHRISTIAAN H. BOU V Y

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