US2531483A - Safety for firing mechanisms for cannon using separate loading ammunition - Google Patents

Description

NOV. 1950 w. SUMMERBELL ETAL SAFETY FOR FIRING MECHANISMS FOR CANNON USING SEPARATE LOADING AMMUNITION Original Filed July 10, 1945 Patented Nov. 28, 1950 SAFETY FOR} FIRING MECHANISMS FOR. ("JANNON' USING SEPARATE LOADING AMMUNITION William Summerbell, Washington, D. 0., Louis J. Rhein, Aberdeen, Md., and Owen D. Hoopes,

Watervliet, N; Y.; Edith May Summerbell executrix of said William Summerbell, de-

ceased.

Original application July 10, 1945. Serial No. 604,286. Divided and this application February 16, 1949, Serial No. 76,742

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 4 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This application is a division of our copending application, Serial Number 604,286, filed July 10, 1945 now Patent Number 2,504,162, and relates to a head-space safety for use in the firing mechanism of large calibre guns and howitzers.

It is the principal object of the invention to provide a safety device in connection with a firing mechanism wherein the extractor of the primer cartridge cannot be moved forward to fully seated position when the firing lock housing is not screwed fully home, on the obturator spindle.

A further object is to provide a mechanism wherein the operation of screwing the firing lock housing fully onto the obturator spindle, automatically releases the primer cartridge extractor for full forward movement into firing position.

In short, the principal object is to provide a safety mechanism by which firing of the gun is positively prevented unless and until the mechanism is fully seated in gas-tight relation with the obturator spindle.

Other objects and advantages will become apparent after a study of the following disclosure.

The invention is intended more particularly for use in cannon of relatively large calibre such as the Armys 8-inch, 155 mm., and 240 mm. guns and howitzers. In these cannon the projectile and propellant are separately loaded. Ignition of the charge is effected by a firing mechanism screwed onto an obturator spindle rigidly united with the breechand having a central flash passage leading therethrough to the breech chamber whenthe breech is closed. Firing of the cannon is then effected by the detonation of a primer cartridge confined in the passage in the obturator spindle plug, in alignment with and in communication with, the obturator spindle passage. Since this passage is in direct communication with the breech chamber and is subjected to the full pressure engendered by ignition of the propellent therein, it is highly important that the firing mechanism be fully seated and in gas tight relation with the obturator spindle before a round is fired.

The description of the constructionof the firing lock, its operation and its relation to the breech of the cannon, are all fully detailed and described in the parent application aforesaid and hence need not be here repeated.

In the drawings.

Fig. 1 is a vertical axial cross section through the rear end of the obturator spindle, spindle plug, extractor and safety.

Fig. 2 is a vertical section taken in a plane identified by the line 22 of Fig. 1,

Fig. 3 is an exploded perspective view of the housing, safety plunger, plunger spring and extractor, and

Fig. 4 is a perspective view to an enlarged scale, of the safety or plunger.

The model illustrated is for a gun having a breech ring with interrupted threads, a breechblock carrier hinged to the breech ring on an axis which is normal to the bore axis of the gun, and a breechblock pivoted in the aforesaid carrier upon an axis which is substantially coincident with the bore axis of the barrel when the breech is closed, whereby the breechblock may be locked in the breech ring by means of the usual interrupted threads and a partial turn of the breechblock.

Thus numeral l identifies a portion of the aforesaid breech carrier having a central bore 2 and a counterbore 3 opening through the rear face of the carrier. The rear end of obturator spindle 4 has a rotatable sliding fit in bore 2. A firing lock housing 5 has a first or rear, generally cylindrical portion 6 slidably fitting counterbore 3 and a reduced forward extension 1. This extension has an internally threaded bore 9 and an outer diameter sufficiently less than the diameter of counterbore 3 to provide an annular chamber accommodating spring 8. The threads of bore 9 engage those upon the rear end of spindle 4 as will be obvious from inspection of Fig. 1. Spring 8 exertsa force at one end against the shoulder between portions 6 and l and at the other end against the shoulder between bores 2 and S, to thereby urge the spindle 4 and housing 5 rearwardly.

' The rear end of spindle 4 has a threaded counterbore l0 concentric of bore or flash passage i5 and into which the reduced forward end I I of spindle plug I2 is threaded. Spindle plug l2 has an enlarged cylindrical portion 93 rearwardly of "the top of bore l5.

its reduced end II, and a rear portion M of reduced diameter.

As clearly shown upon Fig. 1, when plug 12 is screwed home, its forward end is in gastight relation with a shoulder formed between counterbore I and bore I of spindle 4. Tight sealing relation is assured by a washer l6.

Housing 5 has a reduced bore rearwardly of threaded bore 9 to fit portion [3 of spindle plug I2 and is again reduced to form a bore it opening through its rearward face to accommodate rear portion M of plug 12. The portion I4 is of substantially smaller diameter than bore I6 so that extractor H has a smooth fit between them.

Housing 5 is provided with a smooth radial bore l8, which at its inner end, opens into bore IS. A safety or plunger i9 has a fit within bore l8 and a reduced inner end 22 adapter to project into bore [6 under certain conditions subsequently explained. The safety I9 is urged into radially inward or looking position by a coil spring 25 acting between the bottom of a bore in the safety and a plug 2! threaded into the enlarged outward end of bore 18. It will be noted from Fig. 4 that the main cylindrical portion of safety [9 and its reduced inner end 22, are joined by a smooth, frusto-conical cam surface 23 for a purpose presently described.

Spindle plug l2 has a central axial bore to accommodate a primer cartridge C whose head has a rim seating on the complementary rim surface of extractor l1 and is thus adapted to be withdrawn from the spindle plug bore by withdrawal of the extractor. The extractor is operated by a firing lock 24 guided for vertical movement on housing 5 by downwardly and rearwardly extending ribs 25 and 26 formed on the confronting walls of a diametral channel 21 opening through the rear face of housing 5. Lock 24 has cam grooves, not shown, in which fit oppositely disposed lugs 28 and 29 on extractor I1. Thus, as the firin lock and its firing pin 35 are moved downwardly from the closed or firing position shown upon Fig. l, the extractor is cammed out of the fully seated position shown to withdraw the cartridge C.

From Figs. 1 and 2 it will be noted that the extractor has a pad 3|. This pad fits within a slot or keyway formed in housing 5 in and along The arrangement limits the motion of the extractor to axial translation. The parts are so dimensioned and related that, when safety 19 is elevated to the position shown in Fig. l, the pad 3| may slide smoothly beneath the reduced end 22. However, when safety I9 is allowed to descend from its position shown, under the urge of spring and with extractor I? in rearward position, end 22 moves into the path of pad 31 and prevents the extractor and its primer from movement into fully seated position.

Prior to use, spindle plug l2 will be screwed fully into the end of spindle 4 and housin 5 and the parts carried thereby are separate and unconnected with the spindle. Extractor II is in retracted position so that safety [9 has its end 22 projecting into bore l6, thus making it impossible to move the extractor and cartridge into firing position.

Housing 5 and its associated parts are placed in operative position on the gun by screwing extension I onto the rear threaded end of obturator spindle 4. As the extension is turned home, the rearward corner of enlarged cylindrical portion l3 of plug [2, engages the frusto-conical surface 23 of plunger l9 and forces the latter outwardly against the action of spring 20. When, and only when, the housing 5 is fully seated on spindle 4. in the position shown upon Fig. 1, plunger 19 is moved outwardly to clear bore l6 and the firing pin slide may be then closed to move the extractor and a primer cartridge therein into fully seated position.

We have thus provided a safety feature which positively prevents the gun from being fired unless and until the firing mechanism is fully seated on the obturator spindle of the gun. It is our desire and intention to reserve all the modifications of the previously-disclosed preferred form of the invention which fall within the scope of the subjoined claims.

We claim:

1. In a firing mechanism for a gun having a breechblock and an obturator spindle having a first central axial flash passage leading through the breechblock thereof, said passage terminating rearwardly in a threaded counterbore, a spindle plug threaded into said counterbore and having an axial passage shaped to receive a primer cartridge and forming a continuation of said flash passage, a housing threadable on said spindle into fully-seated, gas-tight relation therewith, and safety means preventing the full insertion of a primer cartridge in said plug unless and until said housing is threaded on said spindle into fully-seated position thereon.

2. In a firing mechanism for a gun having an obturator spindle, a spindle plug rigidly connected with said spindle and having a chamber to receive a primer cartridge, a housing axially movable on said spindle from an initial to a fully seated position thereon, an extractor for a cartridge slidably mounted in said housing for movement with a cartridge into said chamber, safety means on said housing spring pressed into the path of said extractor, and means normally responsive to axial movement of said housing to fully seated position on said spindle to retract said safety means out of the path of said extractor.

3. In a firing mechanism for a gun having an obturator spindle, a spindle plug threaded into said spindle and forming a chamber for the reception of a primer cartridge, 2. housing threadable onto said spindle from an initial to a fully seated position, thereon, an extractor mounted in said housing and movable into final position in synchronism with movement of a primer cartridge into fully seated position in said chamber, a plunger mounted for radial movement in said housing, a spring urging said plunger to project one end thereof. into the path of said extractor to prevent movement thereof to said final position, said plug being engageable with said plunger to retract the same out of the path of said extractor only when said housing is threaded into fully seated position on said spindle.

4. In a firing mechanism for a gun having an obturator spindle through the breach thereof, a spindle plug threadedly engaged with the rear end of said spindle, said plug having a chamber opening rearwardly through the end thereof to receive a primer cartridge, a firing lock housing threadable onto said spindle from an initial position to a final position in gas-tight relation therewith, an extractor slidable in said housing and engageable with the head of a cartridge to move in a unit therewith as said cartridge moves into said chamber means carried by said housing to move said extractor and a cartridge therein as a unit the path a: said extractor onlywhen said hous- 10 ing is in final position on said spindle, whereby said extractor and a cartridge cannot be moved to firing position until said housing is in said final position.

WILLIAM SUMMERBELL.

LOUIS J. RHEIN.

OWEN D. HOOPES.

No references cited.

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