US2196866A - Dead beat cylinder escapement - Google Patents

Description

M. A. JUILLERAT 2,196,866

DEAD BEAT CYLINDER ESCAPEMENT Filed July 30, 1938 m Ill/L Illlll w Ill w INVENM C: "gunk flrflig Jll/LLERH Patented Apr. 9, 1940 UNITED STATES PATENT OFFICE DEAD BEAT CYLINDER EscAPEMENT Application July 30, 1938, Serial No. 222,087 In Luxemburg July 31, 1937 3 Claims.

The present invention relates to a dead beat cylinder escapement for the regulation of spring and other motors, and particularly applicable to time fuzes actuated by'clockwork. It is known :3 that the cylinder escapement of the Graham type, which is well known in the clockwork art and is used in the ordinary watches because of its simplicity as compared to the chronometer or free anchor escapement, which is of a more costly construction and requires more skill for its correct adjustment, is constituted, as represented in Figures 1 and 2 of the annexed drawing, by a hollow cylinder I with a thin wall (about 1% mm. thick) in which there is formed a first notch 2, called the great notch, the edges of which are provided with impulse lips cooperating with theteeth 3 bent at right angles, of the escape wheel 4 integral with the pinion 5, the cylinder further carrying, at its lower end, another notch 6, of a height smaller than the first, called the small notch and adapted to permit the cylinder l to describe, from its rest position (Figure 2), a half oscillation of an amplitude of about 180 without causing the wheel 4 to move back by striking the arm l of that tooth 3 which, after having given an impulse to the ingoing lip of the great notch, has penetrated inside the cylinder (Figure 2) and is resting, during the swing of the cylinder in one direction, with the apex of its actuating ramp against the inner face of the part 8 of the wall of the cylinder l (Figures 1 and 2) which has been left at the upper part of the great notch 2 I after the latter has been cut out.

The cylinder realized in this way is fragile,

since, on one hand, for obtaining a half oscillation of the order of 180, it is necessary to carve it out deeply by the small notch, so that the remaining solid part 9 of the wall (Figures 1 and 2) shall occupy but a short arc, and, onthe other hand, the cylinder is very strongly hardened in order to resist as much as possible the wear produced by the 432,000 daily knocks and frictions of the teeth of the escape wheel against the wall or brim of the cylinder. Furthermore, the sharp angles of the notches which are out along generating lines of the cylinder, and the forced setting in of the plugs l0, l0 carrying the journals II, II contribute to the fragility of the cylinder which will frequently split apart under the effect of the stresses thusset up.

The above mentioned drawbacks of the Graham cylinder escapement make its application, to certain time devices very dimcult, especially in the case of mechanical time fuzes actuated by a clockwork mechanism, since, on one hand, thedevice would not resist the high stresses produced by the knocks and vibrations to which its parts are subjected, and since, on the other hand, the distance between the axes of the escape wheel and the cylinder must remain absolutely fixed and invariable as the axis of oscillation of the said cylinder must normally coincide exactly with the axis of the fuze and of the projectile.

One has, of course, tried to build cylinder escapements with a short resting period and with small amplitude oscillations, of about in which the brim of the cylinder is supported at one end only and oscillates inside a semi-circular aperture formed in a plate and limiting to a great extent the amplitude of the oscillations of the said cylinder. But such an escapement cannot be regarded as being capable of regulating, to a sufiicient extent and in a sufliciently precise manner, the great variations of the motive force encountered in the mechanical time fuzes.

It has therefore been necessary to design a cylinder escapement construction capable'of giving the balance member oscillations of a sufficient amplitude forproperly regulating the variations of the motive power, due chiefly to the centrifugal force, to the nutation effects, etc.

In the mechanisms of portable watches, the number of oscillations of the balance member are, generally of 18,000 per hour, or about 5 oscillations per second, with an average amplitude of 280 to 300.

In the mechanical time fuzes actuated by clockwork mechanism it has been found, however, that by reason of the short time of their operation, which is, according to the trajectory to be described by the projectile, of 40 to 100 seconds, the number of oscillations of the spring balance member is, according to the type of escapement used, of to 300 per second, or 180,000 to 1,080,- 000 per hour. I

In a mechanical fuze of this sort, the balance member is, of course, very light and its moment of inertia very low with respect to the relatively high force of the driving spring, as compared to the ratio existing in a watch mechanism between the moment of inertia of the balance member and the force of the spiral spring, so that the oscillations of the balance member cannot exceed an amplitude of to in either direction, or, as a whole, to

The escapement according to the present invention is based on the considerations which have just been exposed and it has the object of remedying the drawbacks which have been mentioned, of the usual type of cylinder escapement; said i do drawbacks are also present in the simplified Graham escapement, which has already been proposed for watches and which comprises a cylinder with a single notch cooperating with a flat escape wheel. The simplified cylinder escape of the latter type has been abandoned for watches because it did not prove satisfactory in practical use. The author has thought that he could make an interesting application of this escape to mechanical time fuses, in which the operating conditions are entirely different from those in watches, and he has therefore improved said escape in a manner to render such application possible, considering the very severe conditions in which the escape must work and which are due to the extremely high stresses set up at the moment the shot is being fired.

The cylinder escape according to the present invention is characterised by the fact that the closed curve limiting the said single notch upon the cylinder surface has a round form, with no sharp angles, and that safety coupling means are provided for avoiding any misadjustment of the correct position of the cylinder on one hand with respect to the balance member spring and on the other hand respect to the balance member itself, under the effect of the stresses and forces set up upon firing the projectile.

Thus, by giving the notch a round form, the strength of the cylinder to Violent shocks is considerably increased and any possibility of breaking in the weaker portion is avoided, since the latter does no more contain any sharp angles, while the provision of safety coupling means for the cylinder permits to make the mounting absolutely fixed and invariable and to avoid any accidental misadjustment of the so-called escape position, which is well known by those skilled in the art.

By way of example, one embodiment of the escapement according to the invention has been described below and represented to an enlarged scale on the annexed drawing.

Figure l, referred to above, represents in longitudinal axial and transverse section respectively a cylinder escapement such as is used at the present day in clockwork mechanisms.

Figure 2, which has also been referred to above, shows respectively a transverse section of the cylinder along the line II -II of Figure 1 and a plan View of the escape wheel.

Figure 3 is an elevation of the cylinder according to the invention.

Figure 4 represents in partial section and elevation the removable journal of the cylinder, fixed to the balance member.

Figure 0 shows in partial section and elevation the simplified escapement according to the invention.

Figure 6 is a plan view of the escape wheel of the balance member and a transverse section of the cylinder along the line VI-VI of Figure 5 and showing diagrammatically the operation of the escape mechanism at the moment when the first impulse onto the ingoing lip is about to commence.

Figure '7 is a diagrammatic plan view showing the operation of the escape mechanism after the first impulse unto the ingoing lip, with the apex of the tooth at rest on the inner face of the cylinder, whilst Figure 8 represents diagrammatically the operation of the said escape mechanism after the impulse of the outgoing lip, with the apex of the tooth at rest on the outer face of the cylinder.

The simplified cylinder escapement according to the invention, represented in Figures 3 to 8, comprises a cylinder l2 on which is formed during the make a shoulder I 3 and a. pin H on a part of which is formed one or more grooves 15, the object of which shall be described later. On the outer face of the cylinder is formed a single notch IS with the lips formed simultaneously by means of a profiled milling cutter which leaves no sharp angles after the milling has been effected.

The cylinder is coupled to the balance member I! by means of a journal l8, acting as a plug, the stem [9 of which is adjusted freely without play in the bore of the cylinder and the angular fixing of the latter to the balance member being obtained by the provision of a flat part on both the cylinder, in 20, and on the journal l8, in 2|. This journal I8 is also integral with the second pin 23 of the cylinder.

With this means of adjustment and coupling of the journal [8 to the cylinder l2, the latter is no more stressed, thus eliminating the possibility of any cracking of the cylinder, as will occur in the usual type of cylinder with plugs driven in by force.

A fiat escape wheel 22 punched out in one single operation and having the edge of its teeth 24 properly ground and polished, cooperates with the lips of the cylinder l2.

As will be seen from Figures 3 to 8, this escape mechanism is of an extremely simple construction and the interchangeability of the flat escape wheel is provided by the punching out process used for manufacture.

In Figure 6, the cylinder is seen in the rest position, at the moment when the first impulse in the direction of the arrow 1 on the ingoing lip is about to start. In Figure '7, this impulse has given rise to a half-oscillation of the cylinder in a clockwise direction, the amplitude of which attains about without causing the outgoing lip of the cylinder to strike the base 25 of the tooth 24 and forcing the wheel to move back. In this view, it will be seen that after the escape, the tooth 24 remains at rest against the inner face of the cylinder [2, and, at the end of the oscillation, the latter, urged by the spring 28 of the balance member (represented on Figure 5), will be just about to start swinging back into the opposite direction indicated by the arrow f.

In Figure 8, it will be seen that, after the escape and a corresponding impulse on the outgoing lip, the next tooth 24 of the wheel 22 is at rest against the outer face of the cylinder. It will be seen that the latter will end its half-oscillation also with an amplitude of 85.

The grooves l5 formed on a part of the cylinder pin 14 are fitted with a ring 2'! of more ductile metal, engaging the cylinder with a tight fitting. On said ring is fixed the spring 28 of the balance member which may be of any convenient form, for instance a torsion blade or a spiral spring, etc.

Due to the fact that the cylinder is provided on one hand with a pin made directly in one part with the cylinder, and, on the other hand, with a grooved part formed on said pin, there is pr0- vided a practically perfect safety against any future misadjustment of the ring attached to the spring of the balance member, with respect to the cylinder.

Furthermore, it should be remarked that due to the provision of only one notch in the cylinder, without any sharp angles, the resistance of the latter may be considerably increased since the cross section of the remaining portion 26 (Figure 6) has substantially the profile of a concentric U, the high resistance features of which are well known.

Lastly, due to the fact that the escape wheel is obtained by a punching out operation, there is provided a perfect interchangeability of this extremely important part of the mechanism, at very reduced cost price.

What I claim is:

1. In mechanical clockwork time i uses for projectiles, a dead beat cylinder escapement comprising a hollow cylinder provided with a-slngle notch of rounded form without sharp angles and with ingoing and outgoing bevelled lips on the edge of said notch, a flat escapement wheel provided with a series of teeth having suitably curved impulse surfaces cooperating with said ingoing and outgoing lips of the cylinder, a balance memher, a spring for actuating said balance member, safety means for coupling said cylinder to said spring so as to prevent any misadjustmentof the correct position of said cylinder with respect to said spring under the effect of the forces set up at the firing of the projectile, and. safety means for coupling said cylinder to said balance member so as to prevent any misadjustment of the correct position of said cylinder with respect to said balance member under the effect of the forces set up at the firing of the projectile. I

2. In mechanical clockwork time fuses for projectiles, a dead beat cylinder escapement according to claim 1, in which said first mentioned safety coupling means comprise a ring of ductile metal rigidly secured to one end of said spring, and a pin formed in one piece with said cylinder and provided at its end with a series of grooves engaging said ring with a tight fit.

3. In mechanical clockwork time fuses for projectiles, a dead heat cylinder escapement according to ciaim l, in which said second mentioned safety coupling means comprise a journal carrying said balance member, a pin integral with said journal and adjusted freely but snugly in the core said cylinder, a flat surface provided on said journal and on said cylinder for the angular fixing of the latter two parts to one another.

MAURICE ARISTE JUILLERAT.

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