US3286633A - Constant frequency escapement mechanism - Google Patents

Description

Nov. 22, 1966 ca. 5. WESTERMAN 3,286,633

CONSTANT FREQUENCY ESCAPEMENT MECHANISM Filed Sept. 5, 1964 2 Sheets-Sheet 1 Fig/ INVENTOR.

GEORGE S. W STERMAN 7 i ATTORNEYS Nov. 22, 1966 ca. S..WESTERMAN 3,286,633

CONSTANT FREQUENCY ESCAPEMENT MECHANISM Filed Sept. 5, 1964 2 Sheets-Sheet 2 -62 69' ml HHHIH I! J? 7 W t? INVENTOR. 34 7 7 GEORGE S.WESTERMAN 3 37' BY m M44. WM

7 ATTORNEYS United States Patent 3,286,633 CONSTANT FREQUENCY ESCAPEMENT MECHANISM George S. Westerman, Cinnaminson, N..I., assignor to the United States of America as represented by the Secretary of the Army Filed Sept. 3, 1964. Ser. No. 394,367 4 Claims. (Cl. 102-84) The invention described herein may :be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty there- This invention relates to timing mechanisms and, more particularly, to timing mechanisms associated with projectile fuzes.

In time movements of mechanical time fuzes, the escapement area that meters out time is a most critical one. Normally, a block, which is adjustable to a predetermined set position, supports the free ends of a hairspring that controls the beat frequency or oscillation of the escapement lever in the timer. However, when subjected to high speed rotational environment, the hairspring has a tendency to stiffen from the effects of centrifugal force resulting in a decrease in its deflection, which in turn increases the beat frequency, The increase in beat frequency normally makes the timing movement run faster than that for which it had been adjusted. Thus, when precision timing is required particularly in a projectile fuze environment, a deviated setting of the timer from its regulated adjustment is necessary in the field. The present invention eliminates the need for such deviated settings heretofore required in the field for use in a high spin environment.

A primary object of the invention is to provide a timing mechanism adapted to operate at a constant predetermined tbeat frequency when subjected to variable speed effects of rotation.

A further object of the invention is to provide an arcuate timing mechanism capable of compensating for tendencies of its hairspring frequency to deviate when placed in a dynamic environment.

These and other objects and advantages of the invention will become apparent from the following description and accompanying drawings in which:

FIG. 1 is an elevational view partly broken away in section to show the timing mechanism of a projectile fuze;

FIGJZ is a sectional view taken along line 22 of FIG. 1;

-FIG. 3 is an enlarged perspective view of a preferred support arrangement for an end of the hairspring shown in FIG. 2;

FIG. 4 is an elevational view of the firing pin locking arrangement;

FIG. 5 is a sectional elevation view of the adjustable arrangement supporting a hairspring end; and

FIG. 6 is a view similar to FIG. 2 with certain parts removed and others enlarged showing the escapement area of the mechanism,

The projectile fuze, generally shown at 10 (FIG. 1), is provided with rearwardly located attaching or threaded means 11 for connection to a forward portion of projectile body 12 as the forward nose portion thereof. The timer mechanism or movement assembly shown generally at 13 is mounted within the fuze for rotation therewith as the projectile spins during its flight. The mechanism 13 includes a spirally wound spring 14 having its outer end attached or secured to a fixed internal member 16 and its inner end connected to central shaft 18 rotatably positioned about a longitudinal axis of the fuze. Gear 20 carried by shaft 18 is interconnected by gear train elements 21, 22, 23, 24, 25, 26 to escapement gear 27 which is driven by gear 26 carried by common shaft 28. Escapement gear 27 (FIGS. 2, 6) is thus biased by the stored'energy in spirally wound spring 14 for rotation as controlled by the pallets 30', 31 of an oscillating escapement lever 32. The radially central portion 35 of shaft 33 carrying escapement lever 32 is rigidly connected to hairspring 34 substantially at the mid-point thereof. Each of the hairspring free ends 36, 37 is positioned in appropriate slots or grooves 38 (FIGS. 3, 6) of an upstanding leg member 39 of an adjustable and self-compensating support arrangement generally shown at 40 (FIGS. 3, 5, 6) and to be more fully described hereinafter.

Referring again to FIG. 1, firing pin 41 is cocked with its shaft 42 spring loaded and which when released will ignite detonator 43. Compression spring 44 on shaft 42 is compressed between shaft collar 45 and a suitably recessed shoulder 46 on a stationary member of the movement assembly 13. A locking cam 47 (FIGS. 1, 4), for normally retaining collar 45 in a retracted position, is pivotally carried by post 48 suitably journalled in fixed or stationary members or plates 49 of the movement assembly. A torsion spring loaded shaft 50 (FIG. 4), appropriately journalled in stationary movement assembly members, normally engages cam 47 in the cocked position of firing pin collar 45 until the timing mechanism has run its predetermined time when a circumferential opening 52 in timing disk 53 rotated by shaft 18 is aligned with and receives an offset projection 54 of the thusly rotated shaft 50. Minute predetermined rotation of shaft 50 and recess 55 therein will immediately free cam 47 to be withdrawn from locking the firing pin collar 45, enabling the spring biased firing pin 41 to stab or ignite the detonator.

Preferably, each hairspring end 36, 37 is provided with a support arrangement 40 having an upstanding slotted leg 39 that is confined to movement along a predetermined straight line extending through the hairspring and escapement lever central connection 35, and which slidingly supports its respective hairspring end at respective positions such that the central connection 35 is at all times equidistant therefrom. Each of the support arrangements 40, symmetrically positioned about the hairspring and lever connection 35, includes a housing or block body (FIGS. 3, 5, 6) which preferably has formed in its upper surface a centrally located, longitudinally extending slot 61 that communicatively intersects with a lengthwise, central cylindrical bore or passageway 62. The passageway 62 is closed at one end 63, but otherwise extends substantially the full length of the housing. The open end of the passageway has intersecting lateral openings for containing a pin 64' to retain a transversely apertured cover plate 64 in secured position, after a controlled defiection spring 65 and a cylindrical block 66 have been inserted in their appropriate positions. The closed end 63 preferably is counterbored to satisfactorily retain spring 65 in a desired central position biasing cylinder 66 against cover plate 64, and cylinder 66 is formed with a threaded lateral surface opening to receive appropriate mating threads 67 on the bottom of support leg 39 which passes through slot 61. A longitudinal threaded bore 68 is provided in the lower central portion of each housing and receives a corresponding threaded adjusting screw 69 which is retained in proper position by its collar 69 in an appropriate keeper '70. A slot 71 in the head end of each screw 69 enables each of the housings 60 to be independently adjusted lengthwise of the hairspring 34 and relative to the connection 35.

With the foregoing construction it should be apparent that after each support leg 39 has been basically adjusted to a predetermined regulated position relative to the hairspring, further adjustments in the field are no longer necessary to compensate for subsequently predicted high spin environments since centrifugal force developed will urge the cylinders 66 outward against the respective deflection springs 65. The resulting outward movement of legs 39 increases the effective length of the hairspring to compensate for any tendency that centrifugal force effects would have upon the beat frequency of the timer. Thus, the hairspring can maintain its normal reciprocatory movements between deflected S positions, one of which is shown in dotted lines illustrating the hairspring ends 36, 37 (FIG. 6), in assisting the escapement lever to accurately control the metering of timer power output.

Various modifications or changes may 'be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. A timing mechanism for a projectile fuze comprising, an oscillatory escapement lever for metering timer power output, a hairspring connected to said lever and controlling the oscillation thereof, means slida'bly mounted for reciprocatory movement substantially along a line extending through said hairspring and lever connection and supporting end portions of said hairspring, and mean biasing said supporting means toward said connection, so constructed and arranged that when the timing mechanism is subjected to high speed rotation, said supporting means will maintain a substantially constant predetermined beat frequency therein.

2. A timing mechanism as defined in claim 1 in which said supporting means are provided with independently adjusting means.

3. In a projectile fuse timing mechanism having an oscillatory escapement lever for metering timer power output, a hairspring having a central portion connected to a central portion of said lever and controlling the oscillation of said lever, and means supporting end portions of said hairspring, said support means including a pair of housings each having a passageway substantially symmetrically positioned about a common center line passing through said lever and hairspring connection, a movable block in each passageway, means in each passageway biasing one end of the :block therein towards said connection, and means connected to each block and slidingly receiving a respective hairspring end portion, by virtue of all of which each block may be moved against its biasing means for adjusting the effective lengths of said hairspring to maintain a substantially constant predetcnmined beat frequency in the timing mechanism when the latter is subjected to high speed rotation,

4. The structure recited in claim 3 wherein said housings are adjustable along said common center line.

References Cited by the Examiner UNITED STATES PATENTS 2,226,669 12/ 1940 Perrenoud 10284 2,406,730 8/1946 Whitehead 581 17 3,168,833 2/1965 Popovitch 102-84 X BENJAMIN A. BORCHELT, Primary Examiner. G. H. GLANZMAN, Assistant Examiner.

Claims (1)

1. A TIMING MECHANISM FOR A PROJECTILE FUZE COMPRISING, AN OSCILLATORY ESCAPEMENT LEVER FOR METERING TIMER POWER OUTPUT, A HAIRSPRING CONNECTED TO SAID LEVER AND CONTROLLING THE OSCILLATION THEREOF, MEANS SLIDABLY MOUNTED FOR RECIPROCATORY MOVEMENT SUBSTANTIALLY ALONG A LINE EXTENDING THROUGH SAID HAIRSPRING AND LEVR CONNECTION AND SUPPORTING END PORTIONS OF SAID HAIRSPRING, AND MEANS BIASING SAID SUPPORTING MEANS TOWARD SAID CONNECTION, SO CONSTRUCTED AND ARRANGED THAT WHEN THE TIMING MECHANISM IS SUBJECTED TO HIGH SPEED ROTATION, SAID SUPPORTING MEANS WILL MAINTAIN A SUBSTANTIALLY CONSTANT PREDETERMINED BEAT FREQUENCY THEREIN.

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