US2138234A

US2138234A - Projectile fuse

Info

Publication number: US2138234A
Application number: US207085A
Authority: US
Inventors: Henry Pierre
Original assignee: Mefina SA
Current assignee: Mefina SA
Priority date: 1937-05-25
Filing date: 1938-05-10
Publication date: 1938-11-29
Anticipated expiration: 1955-11-29
Also published as: GB498780A; NL47205C; FR833503A; BE426510A; CH197622A

Description

Nov. 29, 1938. P. HENRY PROJEGTILE FUSE Filed May 10, 1938 Pic-1.1.

FIG.4.

@HVENTOR HENRY PIERRE ATTYS Patented Nov. 29, 1938 UNETED STATES PROJECTHIE FUSE Pierre Henry, Geneva, Switzerland, assignor to Mefina S. A., Binningen, Switzerland, a corporation of Switzerland Application May 10, 1938, Serial No. 207,085 In Switzerland May 25, 1937 16 Claims.

This invention relates in general to improved 'safety mechanism for clockwork time fuses for projectiles and more particularly has reference to a. clockwork time fuse for projectiles to be set for a fraction of a revolution. The hammer or firing pin of the fuse is tensioned by a spring and is held fast in this tensioned position by a centrifugally actuated bolt controlled by a time regulating member driven by the clockwork until at the end of a period corresponding to a previously adjusted setting, the time regulating member releases the bolt held against the centrifugal force acting thereon, so that the now freely movable hammer or firing pin is projected under the action of the spring against the detonator and effects the explosion of the projectile.

In such fuses it is known to lock the hammer or firing pin holding bolt, in addition to the time regulating member, by the provision of a second belt which, on firing the projectile, will, due to its inertia, move to an inoperative position and thereby release the hammer holding bolt. This additional safety mechanism is intended to render the projectile safe during transportation, in that any premature explosion thereof is prevented, even if the clockwork should inadvertently come into operation.

There are, however, serious defects in the known fuses, due to the safety means coming into operation through their inertia, especially "the deficient security after setting, since the resistance, which has to be overcome by inertia bolts at their change of position, cannot be selected at will, but must be a function of the acceleration of the projectile arising at the firing thereof. Thus, in fuses for projectiles having low initial speed, an unintentional release may occur, for example, through accidental dropping of an already set projectile from even a low height of a few decimeters. Such projectiles might, as the release is not outwardly visible, immediately explode at a subsequent alteration of the setting.

An object of the present invention is to devise a safety mechanism free from this defect and which provides for complete security, both during the setting operation and during the transportation of a projectile in the set condition.

Another object of this invention is to provide a fuse, the setting of which can be altered or put back at any time without danger independently of the previous set period, as only a running down of the time regulating member and a simultaneous minimum rotation of the projectile can effect the release of the hammer or firing pin.

A further object is to provide a construction in which the safety bolt on one side fixes the zero position of the setting and on the other side is itself locked in this zero position by the time regulating member against accidental release.

Still another object is to provide a safety mechanism so constructed that through its positive release it immediately allows the setting, but on the return of the time regulating member to the zero position it again automatically assumes the locked position when it is not subjected to centrifugal force exceeding a given amount, which secures it. in the releasedposition and so renders the release of the hammer or firing pin possible.

With these and other important objects in View, which may be incident to my improvements, the invention resides in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements comprising my invention may be varied in construction, proportions and arrangement, without departing from the spirit and scope of the appended claims.

An example of construction of the invention is illustrated in the accompanying drawing, in which:

Figure 1 is an axial sectional View taken through the lower part of a time fuse according to the present invention.

Fig. 2 is a sectional and partial top View taken on the line lI-II of Fig. 1 and shows the safety members in the zero position.

Fig. 3 is a view similar to Fig. 2 showing the positions of the members at the maximum setting,

Fig. 4 is another view similar to Fig. 2 showing the position of the members during the flight of the projectile immediately before the disengagement of the hammer locking bolt.

As shown in the drawing, the fuse comprises a framework I mounted in a casing 2. The lower end of the framework is provided with a sleeve 12, in which the hammer or firing pin in is slidably mounted.

Hammer or firing pin I 0 is subjected to the projectile. The inner edge of the bolt 13 engages in a notch l5 of the hammer or firing pin Ill, while the tip 16 of its outer edge bears against the inner face of an annular abutment l! of a toothed crown l8. The toothed crown together with its abutment N form the time regulating member which, by means of a pinion I9, is in connection both with the driving shaft 2!! of the clockwork and with exterior setting members (not illustrated) In the annular abutment I! of the toothed crown I8 is a gap 2! (Fig. 3), which extends about one-twelfth of its circumference and is so formed that at one end the end surface 22 forms ,an'

In the toothed crown l8 a space between two teeth is omitted (no space formed between two adjacent teeth) at a place previously determined by the position of the gap 2!, so that an abutment 24 is there formed which cooperates with pinion H! to limit rotation of crown is. This fixes the maximum setting, which is effected by a counter-clockwise rotation of crown l8 from the position of Fig. 2, so that the gap 22 cannot in any case during the setting operation come before the tip it of the swinging bolt 13 to permit said bolt to swing out of notch i5 and thereby release the hammer H) (see Fig. 3).

Under the swinging bolt [3 in the breech 25 of the fuse, a radial recess 26 is provided in which a second bolt 2'!v is slidably mounted and urged inwardly by a spring" 28. This bolt 21, which is the safety bolt, is provided with a head 29 having an inner surface 39 inclined with respect to the radial central plane of. the bolt. The outer surface 3| of the safety bolt. head opposite the surface 23 of the abutment H is shaped so that in the zero position (Fig. 2) these two surfaces harmonize, being placed obliquely against the direction of force, the parts having the position illustrated in Fig. 2. In this zero position the safety bolt 27, which is atits innermost radial position, prevents a clockwise rotation of the toothed crown is, while, due to the wedging action of the surface 23 of the toothed crown abutment on the surface 3| of the safety bolt, an effectual locking of the whole safety system is obtained. It will be noted that in this locked or zero position, the inner surface of abutment ll adjacent the end 3?. prevents outward movement of the locking bolt it. This locking of the system can only be released by setting of the fuse, when the time regulating member is rotated counter-clockwise against the motive power of the clockwork. Upon counter-clockwise rotation of the toothed crown, the tip 32 of the toothed crown abutment slides along the surface 3d of the safety bolt and thereby shifts the safety bolt 2'! against the action of the spring 28 into the position shown in Fig. 3. In the case of an eventual setting back to zerothat is, upon a clockwise rotation of the toothed crownthe safety bolt, due to the action of the spring 28 (no centrifugal force acting on the bolt), automatically moves back into the original locking position. It will be seen that the bolt l3 can therefore arrive in the notch 2i and release the hammer or firing pin In only when the safety bolt 21, as shown in Fig. 4, is urged radially outwardly by centrifugal. force against the action of the spring 28 and when the toothed crown through the action of the clockwork has rotated some degrees clockwise beyond the zero position (Fig. 2). In the zero position, as can be seen from Fig. 2, a distance between the pinion l9 and the shoulder 24 of the toothed crown must remain corresponding to a rotation through a few degrees of the toothed crown.

The function of the safety bolt 27 is fourfold:

Firstly, as can be seen from Fig. 2, the safety bolt when not subjected to centrifugal force fixes the zero position of the setting, as it prevents the toothed crown l8 from a further clockwise rotation, which might result in the release of the hammer bolt l3 under the effect of an accidental lateral blow on the projectile. This, of course, would cause the immediate explosion of the projectile. I

Secondly, the safety bolt 21 is locked in the zero position of the setting (Fig. 2) against any accidental release.

Thirdly, the safety bolt 21 will allow counterclockwise rotation of the toothed crown, as is necessary at setting, and will again return automatically under the action of spring 28 into the locking position shown in Fig. 2 upon the reversal of the rotation of the toothed crown.

Fourthly, the safety bolt 27 must, upon the rotation of the projectile during flight, move to a position under the action of centrifugal force thereon, as soon as this force is greater than the opposing force of the spring 28, at which position said safety bolt 2? will not check the desired release of the hammer or firing pin locking bolt i3.

It is obvious that instead of the radially movable safety bolt Z'l, any other member removable from the path af the time regulating member can also be employed, for example, an eccentrically mounted swinging bolt.

While I have shown and described the preferred embodiment of my invention, I wish it to be understood that I do not confine myself to the precise details herein set forth by way of illustration, as it is apparent that many changes and variations may be made therein by those skilled in the art, without departing from the spirit of the invention or exceeding the scope of the appended claims..

I claim:

1. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt adapted to be displaced by centrifugal force when the projectile is in flight, means urging said bolt to an inner position when not subjected to the centrifugal force of flight, and means on saidsafety bolt cooperating with the setting control member when the bolt is in its inner position for limiting rotary movement of said member in a given direction to determine the zero position of said member and for locking said bolt against accidental release, said means on the bolt permitting movement of the settin member in an opposite direction but acting in the'absence of centrifugal force on said bolt to again limit movement in said given direction beyond the zero setting, said bolt when subjected to centrifugal force being displaced to shift the means carried thereby out of cooperative engagement with said member.

2. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt normally in a position to block rotation of the control member in its driven direction beyond a given limit, said safety bolt being adapted to be moved outwardly by centrifugal force when the projectile is in flight to permit driven rotation of said control member beyond the given limit, and cooperating means on said safety bolt and control member operable upon rotation of the control member in a direction opposite from that in which it is driven for displacing the safety bolt outwardly to permit such opposite rotation for setting the control member.

3. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt, means urging said safety bolt to a position to block rotation of the control member in its driven direction beyond a given limit, said safety bolt being adapted to be moved outwardly by centrifugal force when the projectile is in flight to permit driven rotation of said control member beyond the given limit, and cooperating means on said safety bolt and control member operable upon rotation of the control member in a direction opposite from that in which it is driven for displacing the sefety bolt outwardly against said urging means to permit such opposite rotation for setting the control member.

4. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a radially movable safety bolt, means urging said safety bolt to a position to block rotation of the con trol member in its driven direction beyond a given limit, said safety bolt being adapted to be moved outwardly by centrifugal force when the projectile is in flight to permit driven rotation of said control member beyond the given limit, and cooperating means on said safety bolt and control member operable upon rotation of the con trol member in a direction opposite from that in which it is driven for displacing the safety bolt outwardly against said urging means to permit such opposite rotation for setting the control member.

5. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt normally in a position to block rotation of the control member in its driven direction beyond a given limit, said safety bolt being adapted to be moved outwardly by centrifugal force when the projectile is in flight to permit driven rotation of said control member beyond the given limit, and means for locking said safety bolt against outward movement when in blocking engagement with said control member.

-6. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt normally in a position to block rotation of the control member in its driven direction beyond a given limit, said safety bolt being adapted to be moved outwardly by centrifugal force when the projectile is in flight to permit driven rotation of said control member beyond the given limit, cooperating means on said safety bolt and control member operable upon rotation of the control member in a direction opposite from that in which it is driven for displacing the safety bolt outwardly to permit such opposite rotation for setting the control member, and means for looking said safety bolt against outward movement when in blocking engagement with said control member.

'7. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt normally in a position to block rotation of the control member in its driven direction beyond a given limit, said safety bolt being adapted to be moved outwardly by centrifugal force when the projectile is in flight to permit driven rotation of said control member beyond the given limit, and means including a surface on said safety bolt oblique to the direction of movement of said safety boltand a surface on the control member oblique to the circumferential movement of said member adapted to cooperate with the oblique surface on the safety bolt to urge the bolt inwardly upon engagement of said oblique surfaces and the exertion of pressure on said bolt by the control member, whereby outward movement of said safety bolt is blocked.

8. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt normally in a position to block rotation of the control member in its driven direction beyond a given limit, said safety bolt being adapted to be moved outwardly by centrifugal force when the projectile is in flight to permit driven rotation of said control member beyond the given limit, and cooperating means on said safety bolt and control member operable upon rotation of the control member in a direction opposite from that in which it is driven for displacing the safety bolt outwardly to permit such opposite rotation for setting the control member, said control member having a toothed portion, a pinion meshing with said toothed portion, and an abutment carried by said toothed portion for limiting rotation thereof.

9. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt normally in a position to block rotation of the control member in its driven direction beyond a given limit, said safety bolt being adapted to be moved outwardly by centrifugal force when the projectile is in flight to permit driven rotation of said control member beyond the given limit, and cooperating means on said safety bolt and control member operable upon rotation of the control member in a direction opposite from that in which it is driven for'displacing the safety bolt outwardly to permit such opposite rotation for setting the control member, said control memher having a toothed portion, a pinion meshing with said toothed portion, and an abutment formed on said toothed portion by the omission of a space between two adjacent teeth and adapted to cooperate with said pinion for limiting the rotation of said member.

10. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt mounted for movement outwardly by centrifugal force produced by rotation of the projectile in flight, means urging said safety bolt to an inner position when not subjected to centrifugal force, a blocking cam surface formed on said safety bolt and extending obliquely to the direction of movement of said safety bolt, and a blocking cam surface formed on said rotary control member and inclined to engage and cooperate With the blocking cam surface of the safety bolt when said safety bolt is in its innermost position, to retain the safety bolt in its innermost position, and to block rotation of said member in the direction in which it is driven by the clockwork.

11. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt mounted for movement outwardly by centrifugal force produced by rotation of the projectile in flight, means urging said safety bolt to an inner position when not subjected to centrifugal force, a blocking cam surface formed on said safety bolt and extending obliquely to the direction of movement of said safety bolt, a blocking cam surface formed on said rotary control member and inclined to engage and cooperate with the blocking cam surface of the safety bolt when said safety bolt is in its innermost position, to retain the safety bolt in its innermost position, and to block rotation of said member in the direction in which it is driven by the clockwork, a releasing cam surface formed on said safety bolt extending obliquely to the direction of movement thereof, and a releasing cam surface formed on said rotary control member and inclined to cooperate with the releasing cam surface of said safety bolt upon rotation of the control member in a direction opposite from that in which it is driven by the clockwork to displace the bolt outwardly.

12. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt mounted for movement outwardly by centrifugal force produced by rotation of the projectile in flight, means urging said safety bolt to an inner position when not subjected to centrifugal force, a blocking cam surface formed on said safety bolt and extending obliquely to the direction of movement of said safety bolt, and a split annular flange carried by said rotary member, one end face of said annular flange being inclined to form a blocking cam surface adapted to engage and cooperate with the blocking cam surface of the safety bolt when said safety bolt is in its innermost position, to retain the safety bolt in its innermost position, and to block rotation of said member in the direction in which it is driven by the clockwork.

13. A safety mechanism for clockwork time fuses of projectiles, comprising a rotary clockwork driven time setting control member, a safety bolt mounted for movement outwardly by centrifugal force produced by rotation of the projectile in flight, means urging said safety bolt to an inner position. when not subjected to centrifugal force, a blocking cam surface formed on said safety bolt and extending obliquely to the direction of movement of said safety bolt, a split annular flange carried by said rotary member, one end face of said annular flange being inclined to form a blocking cam surface adapted to engage and cooperate with the blocking cam surface of the safety bolt when said safety bolt is in its innermost position, to retain the safety bolt in its innermost position, and to block rotation of said member in the direction in which it is driven by the clockwork, a releasing cam surface formed on said safety bolt extending obliquely to the direction thereof, and a releasing cam surface formed on the other end of said annular flange and inclined to cooperate with the releasing cam surface of said safety bolt upon rotation of the control member in a direction opposite from that in which it is driven by the clockwork to displace the bolt outwardly.

14. In a device of the character described, a firing pin, a centrifugally actuated bolt for looking and releasing the firing pin, a rotary clockwork driven time setting control member, a safety bolt mounted for movement outwardly by centrifugal force produced by rotation of the projectile in flight, means urging said safety bolt to an inner position when not subjected to centrifugal force, a blocking cam surface formed on said safety bolt and extending obliquely to the direction of movement of said safety bolt, a split annular flange carried by said rotary member, one end face of said annular flange being inclined to form a blocking cam surface adapted to engage and cooperate with the blocking cam surface of the safety bolt when said safety bolt is in its innermost position, to retain the safety bolt in its innermost position, and to block rotation of said member in the direction in which it is driven by the clockwork, and means on the locking bolt engaging said split flange for retaining said locking bolt in locked position until the split in the flange is reached.

15. In a device of the character described, a firing pin, a centrifugally actuated bolt for looking and releasing said firing pin, a rotary clockwork driven time setting control member, a safety bolt mounted for movement outwardly by centrifugal force produced by rotation of the projectile in flight, means urging said safety bolt to an inner position when not subjected to centrifugal force, a blocking cam surface formed on said safety bolt and extending obliquely to the direction of movement of said safety bolt, a split annular flange carried by said rotary member, one end face of said annular flange being inclined to form a blocking cam surface adapted to engage and cooperate with the blocking cam surface of the safety bolt when said safety bolt is in its innermost position, to retain the safety bolt in its innermost position, and to block rotation of said member in the direction in which it is driven by the clockwork, a releasing cam surface formed on said safety bolt extending obliquely to the direction thereof, a releasing cam surface formed on the other end of "said annular flange and inclined to cooperate with the releasing cam surface of said safety bolt upon rotation of the control member in a direction opposite from that in which it is driven by the clockwork to displace the bolt outwardly, and means on the locking bolt engagingsaid flange for retaining said locking bolt in pin-locking position until the split in the flange is reached.

16. In a device of the character described, a firing pin, a centrifugally actuated bolt for locking and releasing said firing pin, a rotary clockwork driven time setting control member, a safety bolt mounted for movement outwardly by centrifugal force produced by rotation of the projectile in flight, means urging said safety bolt to an inner position when not subjected to centrifugal force, a blocking cam surface formed on said safety bolt and extending obliquely to the direction of movement of said safety bolt, a split annular flange carried by said rotary member, one end face of said annular flange being inclined to form a blocking cam surface adapted to engage and cooperate with the blocking cam surface of the safety bolt when said safety bolt is in its innermost position, to retain the safety bolt in its innermost position, and to block rotation of said member in the direction in which it is driven by the clockwork, a releasing cam surface formed on said safety bolt extending obliquely to the direction thereof, a releasing cam surface formed on the other end of said annular flange and inclined to cooperate with the releasing cam surface of said safety bolt upon rotation of the control member in a direction opposite from that in which it is driven by the clockwork to displace the bolt outwardly, means on the locking bolt engaging said flange for retaining said locking bolt in pin-locking position until the split in the flange is reached, said safety bolt when not subjected to centrifugal force serving to block movement of said flange in one direction to bring the split therein to a. position to permit release of the locking bolt, and means for limiting movement of the flange in the opposite direction to prevent the split reaching a position to release the locking bolt.

PIERRE HENRY.