US2800763A - Power take-off device with staggered ratchets - Google Patents

Description

July 30, 1957 a e. ENSIGN ETALY 2,800,763

POWER TAKE-OFF DEVICE WITH STAGGERED RATCHETS Filed Au 4, 1953 3 Sheets-Sheet 1 INVENTOR$ George G- zhszlyn,

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azennzao ver ad Osszan LundafiZ BY ATTORNEYS cs. G. ENSIGN EI'AL 2,800,763

July 30, 1957 POWER TAKE-OFF DEVICE WITH STAGGERED RATCHETS Filed Aug. 4, 1953 3 Sheets-Sheet 3 m m m mm wiw m S V 1.1 Ev u f 2; m ma ao United States Patent POWER TAKE-OFF DEVICE WITH STAGGERED RATCHET S George G. -Ensign and Glenn T. Soper, Elgin, Ill., and

Ossian Lundahl, Orlando, Fla., assignors to Elgrn National Watch Company, Elgin, 111., a corporation of Illinois Application August 4, 1953, Serial No. 372,218 1 Claim. c1; 58-28) This invention relates to energy-transfer or power takeoff devices for transferring small amounts of energy from an oscillating'member to an intermittently actuated continually advanced member, for example in an electrically actuated wrist watch.

A feature of the invention is the provision of an oscillating member having a projecting part, a rocker member moved by said part and having an actuator, and a continually advancing member having ratchets with staggered orv offset teeth which are successively actuated from the rocker.

Another feature is the provision of an oscillating member having a projecting part, a rocker member moved by said part and having an actuator, and a driven member having ratchets with staggered or offset teeth which are successively and alternately engaged and moved by the actuator during the forward and return strokes of the oscillating member.

A further feature is the provision of a horological assembly including an oscillating member, means for impulsing the same, and a projecting jewel pin moved with the member; a pallet piece having a fork for receiving the pin and being moved thereby, and also having an actuator; and a counting train including a pair of ratchets having their teeth staggered or offset and presented in the path of said actuator for successive and alternate actuation thereby during the forward and return strokes of the member: and in which the pallet piece acts to prevent excessive oscillatory movement.

A further feature is the provision of a power take-01f for an electrically actuated timepiece comprising a balance and train parts mounted with parallel axes, together with a shaft extending in a radial plane relative to the axes and having parts intermittently advanced from said balance and having a worm in driving relation to a train part, whereby a speed reduction is obtained.

With these and other features in view, as will appear in the course of the following description and claim, an illustrative form of practice is shown in the accompanying drawings, in which:

Fig. 1 is a plan view of parts of an electrically ac-. tuated watch, including a staggered-ratchet train drive or power take-off;

Fig. 2 is an upright section on a larger scale, substantially on broken lines 2-2 of Figs. 1 and 3;

Fig. 3 is a horizontal section of the same, substantially on line 3-3 of Fig. 2, that is, with the balance cock and parts of the balance removed;

Fig. 4 is a fragmentary upright section, substantially on line 44 of Fig.v 2.

In the drawings, the watch has a support or frame structure comprising a pillar plate PP, a balance cock BC and bridges and plates 20, 21, 22, 23, on which are mounted the train and the actuator lever, and the magnetizable 2,800,763 Patented July 30, 1957 ice yoke 24 having pole pieces 28 and the electrical winding or coil C. A balance staff BS is journalled in bearings of the plate PP and the balance cock BC and has a diametrical arm 37 connected to the balance wheel r1m BW which carries the diametrically opposed masses MA and MB. The wheel rim and mass MA are of non-magnetizable material; and the mass MB is magnetizable for cooperation with the pole pieces 28 between which it passes as the balance oscillates (Fig. 2). A hairspring collet HSC is connected to one end of the hairspring HS, which at its other end is fixed to a stud HSD on the balance cock BC.

A roller collet RC on the balance staff BS supports a contact fin 50 which during each stroke encounters the contact blade CB near the neutral axis, i. e. at the time of maximum velocity, and causes the blade CB selectively to engage the side contacts 60, 60a whereby to close a current path from the blade CB through the contact 60 to the coil C, during the forward'stroke of an oscillation cycle, or through the contact 6011 to the coil C, during the return stroke thereof. A block 54 of insulating ma terial is fixed on the pillar plate PP by screw 56 and slidingly carries a block 55 on which is mounted the contact blade CB. The block 55 can be moved toward and from the balance axis by the screw 57 which has a flange engaged in a kerf of the block 55: the binder screw 55b holds the block 55 in adjusted position, at the desired depth of engagement of the free end of contact blade CB with the contact fin 50. The side contacts 60, 6011, are also mounted in the block 54 at their bent ends; and a conductor 62 is electrically associated at one end with the side contact pieces and at the other end with a terminal 65 of the coil C. The other terminal 69 of the coil C is connected by conductor 71 insulatedly carried on the plate PP to the connection clip 72. A second connection clip 212 is connected to the plate PP which thus serves as a return conductor. The conventionally illustrated battery B is connected at one terminal to the clip 212 and at the other terminal tothe clip 72: so that when the contact blade CB engages either side contact 60 or 60a, current flows-from the battery to clip 212, the plate PP, screw 55b, block 55, contact blade CB, the contact 60 or 60a, conductor 62, through the coil C, and by conductor 71 and clip 72 back to the battery B. The positions and tensions in the contacts 60, 60a may be regulated by the screws 61, 610, the contact 60 having a bight piece 60d extending beneath the contact blade and contact 60a. Each time the fin 50 causes the blade CB to engage a contact 60, 60a, the-pole pieces 28 are magnetized and deliver an impulse to the mass MB, and thereby the balance system is maintained in oscillation.

According to the present invention, the roller collet RC carries a so-called jewel pin, 51, which may be of ruby, sapphire, metal, or other material. A pallet piece or rocker 10 has tines 11, 12 with a notch between them for receiving the pin 51, and is supported by the pivot 13 carried by the bridge 23 and the pillar plate PP. The pallet piece 10 carries projections providing an actuator 15 which has laterally extending ends having oppositely angled or beveled edges for respective engagement with the teeth of the ratchet wheels 81, 82. The piece 10 also carries a safety pin 19 for engaging in a passing hollow of the safety collet SC in the usual manner during the passing action.

Bearing standards 78 and 79 on the plate PP support a shaft 80 having thereon two ratchet wheels 81, 82 with like numbers of teeth but with these teeth staggered or offset as shown in Figs. 2 and 3,;so that each tooth of one ratchet lies midway of a tooth space of the other ratchet. The lateral span and shaping of the actuator 15 (Fig. 1), and the tooth spacings of the ratchets 81, 82 are so correlated, as shown, that the actuator 15 is free of one ratchet as it completes its actuation of the other ratchet; whereby it permits movement of such other ratchet to a position at which the other ratchet receives the -actuator'into the next succeeding; tooth gap.

A detent ratchet 83isfixed' on the shaft80, andhas twice as many teeth'as either ratchet'81, 82. A detent spring pawl 84 is mounted on the plate PP, and cooperates with the detent ratchet 83 to prevent retrograde movements. A worm 85 fixed on the shaft80 is in mesh with a worm wheel 86 of. the counting train which leads.

tothe indicating hand or hands (not shown) in.usua1 fashion.

In operation, the balance assembly is maintained in oscillatory movement by the successive magnetic impulses delivered thereto. As the roller collet RC approaches neutral axis in the counterclockwise, e. g. forward, stroke, as indicated by the arrow in Fig. 3, the pin 51 passes the tine 11 of the pallet which then has its actuator resting in the ratchet 81, and enters the pallet notch. The pin 51 then acts on the notch wall of tine 12 to rock the pallet clockwise about its pivot 13; at the end of this rocking movement, the pin 51 escapes from the notch and leaves the pallet and continues in its forward stroke against the action of the hairspring HS until it reaches the end of the forward stroke. The balance assembly then moves back in the clockwise or return stroke; as the pin 51 again approaches the neutral axis, it passes the tine 12 as the pallet 10 has its actuator resting in the ratchet 82, and again enters the pallet notch and acts on time 11 to return the pallet 10 by a counterclockwise rocking movement until the pin 51 escapes from the notch and continues to the end of the return stroke of the balance assembly. The safety pin 19 partakes in the pallet movement, and cooperates with the safety collet SC so that the pallet can only move at the proper points in the cycle.

While the actuator rests in the ratchet 81, it lies partly between adjacent teeth of the ratchet 81 and is clear of the ratchet 82 (Fig. 3). During the clockwise rocking of the pallet 10 during the forward balance stroke, the actuator 15 moves into engagement with a tooth of the ratchet 82, causing this ratchet and therewith the shaft 80 to turn as shown by the arrows in Figs. 2, 3 and 4. This motion of the shaft 80 is through an angle of slightly greater than half the arcuate tooth spacing of the ratchet 81, 82 and the pawl 84 passes from one tooth to the next on the ratchet 83. As the shaft 80 turns, the ratchet 81 also moves by a half-tooth, such movement being permitted as theactuator 15 moves from the tooth gap. During the rest of the forward stroke and essentially half of the return stroke of the balance assembly, the actuator 15 remains in' a tooth space of ratchet 82 and clear of ratchet 81. Thereafter whenthe pin 51 moves the pallet 10 clockwise, the actuator leaves the ratchet 82 and enters the next tooth space of ratchet 81 and produces a further half-tooth-space movement of ratchet 81 and of shaft 80. Thus the shaft 80 is intermittently rotated by successive and alternate actuations of the ratchets 82, 81 during the forward and return strokes, so that the shaft 80 is moved by one ratchet tooth angle of either ratchet 81.or 82 for each complete cycle of the balance system. This motion is transferred by worm 85 to the wheel 86 and thus to the train. At each half-step, the detent pawl .84 acts on the detent ratchet 83 to' prevent retrogression.

The balance staif' BS, the train gear 86, and other train parts can be mounted on the support with their axes parallel; and a large speed reduction accomplished by'the stepping of the ratchets and use ofthe worm drive. Forexample, with-a 300-beat balance, and 15 teeth in each ratchet, the-shaft 80 turns 10 revolutions per minute, and with a single thread worm 85, and a gear 86 of 10 teeth, the wheel 86 turns once per minute, i. e. at the proper rate for a seconds pinion, and can be coupled by a 1:1 ratio drive to a center seconds pinion SP.

The structure and conditions of operation are particularly of merit with a balance system which is impulsed during a stroke by means moved by the system, in that such a balance system is normally inherently capable of continuing excessive amplitudes of oscillation. For example, with the illustrative electrically actuated watch, it is desirable to have the balance move for about one and one-half turns, or 270 degrees at each side of the neutral axis, in each stroke. At neutral axis, the impulse is delivered. Now, if a shock occurs in the absence of a motion-limiting device, this amplitude of swing may increase to 360 degrees; whereupon a second movement of the contact blade could occur, with a further impulsing in the same direction, thereby tending to cause an additional forward movement; and during the return a first impulsing occurs as thebalance'regains the position of a two-turns amplitude, a further like return impulse at the neutral axis, and probably a third impulse at two-turns amplitude in the return stroke. This is avoided by the employment of the rocker member of limited motion, because as the amplitude increases toward two turns, the jewel pin 51 ultimately encounters the tine 11 or 12 of the rocker or pallet piece and thereby is brought to a standstill before the pin 51 can again engage and close the contact blade CB. Thus the maximum amplitude is limited to less than 360 degrees or two turns, and it is notable that the various frictions and resistances normally increase with amplitude, whereas the duration of contact closure, and hence the quantity of impulsing energy, decreases with increase of the balance velocity at neutral axis, so that the system tends to regain and to operate at a constant amplitude dependent upon the adjustment of the contactblade CB toward or from the balance staff.

In service, also, the system is effectiveto prevent disturbances and damage during setting, e. g. during movements of the hands to proper time position when the watch is placed in service. When the setting stem is actuated'to cause the hands to move, rotational forces are exerted along the train toward the worm gear 86, but can produce no rotation of the worm 85 and shaft due to the low pitch of the worm teeth. Hence there is no movement of the rocker 10 from the ratchets 81, 82; and no damaging stress exerted between parts on the uocker and parts on the balance.

It is obvious that the invention is not restricted to the illustrative form of practice, but may be employed in many ways within the scope of the appended claim.

We claim:

A power take-off device for an electrically actuated timepiece having a support and an oscillatory balance thereon, comprising a pallet piece rockably mounted on the support for movement from one end position to another about a pivot axis parallel to the balance axis and having a forked end, a first element carried in an arcuate path concurrently with the balance for entering said forked end and moving the pallet piece from one end position thereof to the other and thereafter leaving the said forked end during the continuance of the balance stroke; a shaft rotatably mounted on the support'with its axis spaced from the balance axis and substantially at right angles thereto, a pair of ratchets fixed on the shaft with their teeth staggered, and actuator elements onthe pallet piece and located in a plane parallel to the shaft axis and intersecting the teeth of both ratchets, each said element having an inclined surface cooperative with the teeth of the corresponding ratchet, the said surfaces being oppositely inclined relative to one another; said ratchets being spaced from one another in said plane whereby when" one actuator element is engaged with and moving 6 one said ratchet, the other actuator element moves into References Cited in the file of this patent the space between the ratchets so that the other ratchet can pass the other actuator element; means for prevent- FOREIGN PATENTS ing retrograde movement of the ratchets, and means on 46,460 France Mar. 24, 1936 the pallet piece and balance for preventing movement of 5 (lst addition to No. 779,105) v v the pallet piece from its occupied end position so long as 702,282 France Jam 20, 1931 said first element is out of the said forked end. 480,407 Great Britain Feb. 22, 1938

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