US2871702A - Escapement - Google Patents

Description

R. G. TETRO Feb. 3, 1959 ESCAPEMENT Filed June 18, 1956 15 Sheets-Sheet 1,

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Feb. 3, 1959 R. G. TETRo 2,871,702

ESCAPEMENT Filed June 18, 1956 5 Sheets-Sheet 2 IN1/EN ToR.

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R. G. TETRO Feb. 3, 1959 ESCAPEMENT 3 Sheets-Sheet 3 Filed June 18, 1956 nited States Patent() ESCAPEMENT Roland G. Tetro, Bristol, Conn., nssignor to The E. Ingraham Company, Bristol, Conn., a corporation of Connecticut Application June v18, 1956, Serial No. 592,013

3 Claims. (Cl. Wl-1.5)

This invention relates generally to escapements, and more particularly to escapements which impart timed intermittent snap motion to control devices.

The escapement with which the present invention is concerned is of the type having a rotary escape or output member and a series of augularly spaced stops there'- around, of which the ecsape member is spring-loaded so as intermittently to turn or advance with a lively snap action against and engage consecutive stops on its release from each preceding stop. To this end, there is provided a time-driven member and cam means operated thereby to cause disalignment between the springloaded escape member and each engaged stop and, hence, release of the yformer from the latter, .after a predetermined rest interval, as well as quick operative realignment between the escape member and each stop against which it advances. Further, the torsion-type spring which powers the escape member is not only initially preloaded, but is anchored with its ends to the ,latter and to the time-driven member so that the same will partly unwind on each intermittent advance of the escape member and be fully rewound by the time-driven member during each of the aforementioned rest intervals of the escape member.

One prior escapement of this type is disclosed in the patent to Hall, No. 2,227,133, dated December 31, 1940. ln this prior escapement, disalignment between the spring-loaded escape member and each engaged stop and realignment between the former and each stop against which it advances, are achieved by mounting the escape member for rotation about a fixed axis and providing two stops on a slide which is reciprocated by a cam on the time-driven member so that one stop is moved out of engagement with the escape member and releases the latter for an intermittent advance while the other stop is simultaneously moved into the path of the advancing escape member, and vice versa. While this prior escapement is generally satisfactory', it does have drawbacks in some important respects. Thus, one of its more important drawbacks is its lack of versatility, in that it permits the use of only two stops due tor their provision on a slide and the requirement that they both perform for each intermittent advance of the escape member in releasing and stopping the same, respectively, wherefore the escape member is limited to intermittent advances in equal steps of 18() degrees. An even more important drawback is the difficulty, due to the movability of the stops, of readily attaining in any event that accuracy of coordination between the stops on the slide, lthe escape member and the slide-reciprocating cam, which is imperative to achieve the uniformity of the periodic time-cycle performance of the escapement that is required for most applications. Thus, accurate coordination of these parts requires not only a high degree of accuracy of the parts themselves with hardly any tolerances in size or shape, but also their assembly in an exacting fashion, all of which is hardly conducive to etiicient mass production of this escapementV at low cost.

ICC

Another prior escapement of this type is disclosed in the patent to Black et al., No. 2,678,570, dated May 1S, 1954. In this escapement, the spring-loaded escape member is mounted for compound motion, rotary about the axis of the time-driven member and bodily diametrically thereof, while the stops are fxedly mounted about this axis. The time-driven member is provided with a pair of diametrically opposite cam ngers, While the escape member is provided with av slot having a semicircular wall which is arranged eccentrically with respect to the coinciding rotary axes of these members, and with the cam fingers cooperate in camming the escape member from engagement with each stop while prevented thereby from turning, and in quickly camming the escape member into alignment with each stop against which it advances while the cam iingers lag behind. For its support for rotation coaxially of the time-driven member and Vfor its guidance diametrically thereof, the escape member is slidably mounted in a carrier which, in turn, is mounted for rotation about the axis of the time-driven member. While this prior escapement with its fixed stops avoids the disadvantages of the aforementioned prior Hall escapement springing from the movability of the stops thereof, it has nevertheless the same handicaps as the latter escapement insofar as its adaptability to ei`n`cient and low-cost mass production and also its versatility are concerned. Thus, nothing short of most accurate coordination between the rotary mounting of the carrier coaxially of the time-driven member, its guide provisions for the sliding escape member, the slot in the latter and the cam fingers on the time-driven member, will achieve chord-like contact of the cam iingers with the semicircular slot wall which is imperative if the escape member is assuredly to be cammed from engagement with each stop and as assuredly cammed back into alignment with each stop against which it advances. Needless to say, such accurate coordination of so many parts requires not only exceptional accuracy of the parts themselves with hardly any tolerances in size or shape, but also their assembly in a most exacting fashion, wherefore this prior escapement is hardly adaptable to eicient and low-cost mass production. Moreover, insofar as the versatility of this prior escapement is concerned, the possible intermittent advances of the escape member are confined to a relatively small angular range. Thus, an analysis of the camming action lfor the release of the escape member from each stop and for its realignment with each stop against which it advances, will show that the escape member may intermittently advance in equal steps of 60 degrees as a maximum, while considerably smaller indexing steps of the same may be achieved only at the cost of considerably greater and even prohibitive friction between the cam fingers and semicircular slot wall and also increasingly smaller engagement area between the escape member and each stop, with resulting rapid wear of these parts and ensuing inaccurate performance of the same, as well as possible jamming of the cam action.

It is the primary aim and object of the present invention to provide an escapement of this type which not only has none of the aforementioned drawbacks of the prior escapements, but is also simpler in construction and lower in cost than the latter and, moreover, lends itself to efficient mass production.

Thus, it is among the objects of the present invention to provide an escapement of this type which is far more versatile than the aforementioned prior escapements insofar as the permissible angular range of the intermittent steps of the escape member is concerned.

It is another object of the present invention to provide an escapement of this type which is not only simpler d in construction and lower in cost than the aforementioned prior escapements, but is also more accurate in its performance than the latter.

`It is a further object of the present invention to provide an escapement of this type of which the escape member has compound rotary and bodily linear motion for its intermittent advances against successive stops and for its periodic release from the latter and realignment with the next stops, respectively, while the stops are xedly mounted, thereby to avoid at any rate the aforementioned disadvantages springing from movable stops, as in the prior Hall escapement.

Another object of the present invention is to p'ivide an escapement of this type in which the spring-loaded escape member and the time-driven member are directly located and relatively turnableon a common shaft, and the escape member is additionally providedwith an elongated slot through which the shaft extends ttedly, thereby not only achieving the requisite movability of these members for their proper performance without the need of a carrier for the escape member as in the prior Black. et al. escapement, but also achieving by this exceedingly simple orientation of both members on one and the same shaft accurate relative rotation between them about a single axis and accurate guidance ofthe escape member in any angular position for its bodily motion radially of this axis and, hence, optimum uniformity of the action of the cooperatng cam and follower means on these members in retracting the escape member from each stop and advancing it into alignment with the next stop.

A further object of the present invention is to provide an escapement of this type in which one of the escape and time-driven members is provided with a simple cam formation about their aforementioned common rotary axis and the other member carries simple pin-type follower means in cooperation with the cam formation, thereby not only achieving in mass-produced escapements of this type the aforementioned optimum uniformity of the cam action in retracting the escape member from each stop and advancing it into alignment with the next stop, even despite considerable tolerances in size or shape of the cam formation and/ or pin-type follower means or despite variations in their coordination, but also making absolute uniformity of the rest intervals between successive intermittent advances of the escape member solely conditional upon the equidistant radial spacing of the stops from the common rotary axis of the members, and not at all upon their accurate equiangular spacing from each other. tervals between successive intermittent advances of the escape member is achieved on mere accurate radial spacing of the stops from the common rotary axis of the escape and time-driven members, and this presents no problem Whatever even in mass production of the escapement. v

It is another object of the present invention to provide an escapement of this type in which the time-driven member is directly turnable on the aforementioned common shaft, and the escape member is divided into an escape clement which cooperates with the stops and an output element which is iixedly mounted on this common shaft and is drivingly connected with the escape element by the simple expediency of a key formation which is received with a sliding fit in the aforementioned elongated slot in the escape element, thereby permitting anchorage of the opposite ends of the torsion-type loading spring on the escape element and time-driven member, respectively, with ensuing periodic partial unwinding and rewinding of the spring while the same is advantageously retained in concentric disposition about the common shaft.

Other objects and advantages will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings.

In the accompanying drawings,in which certain modes Thus, the ultimate in uniformity of the rest inr of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a fragmentary elevational view of an escapement embodying the present invention;

Fig. 2 is a fragmentary section through the escapement as taken on the line 22 of Fig. l;

Fig. 3 is a fragmentary section through the escapement as taken on the line 3-3 of Fig. 2;

Fig. 4 is a fragmentary section through the escapement as taken on the line 4 4 of Fig. l;

Fig. 5 is a fragmentary section similar to Fig. 4, but showing certain parts of the escapement in different operating positions;

Fig. 6 is a fragmentary section through an escapement embodying the present invention in a modified manner;

Fig. 7 is a fragmentary section through an escapement embodying the present invention in another modified manner;

Fig. 8 is a fragmentary section similar to Fig. 7, but showing certain parts of the modified escapcment in different operating positions; Y

Figs. 9 and l0 are fragmentary sections through an escapement embodying the present invention in a further modified manner, with certain parts being shown in different operating positions, respectively;

Figs. ll and l2 are fragmentary sections through an escapement embodying the present invention in another modified manner, with certain parts being shown in different operating positions, respectively;

Fig. 13. is a fragmentary section through an escapement embodying the present invention in a further modified manner;

Figs. 14 and l5 are fragmentary sections through an escapement embodying the present invention in another modified manner; and

Fig. 16 is a fragmentary section through an escapement embodying the present invention in still another modified manner.

Referring to the drawings, and more particularly to Figs. l to 5 thereof, the reference numeral 2t) designates an escapement having its major operating parts arranged, in the present instance, between end plates 22 and 24 which are held in spaced parallel relation by a plurality of pillars 26 and nuts 28. The major operating parts of the escapement are, in the present exampie, a time-driven member 3b and an escape member 32, a coupling spring 34 therebetween, an output element 36, a driving connection 33 between the escape member 32 and output element 36, a plurality of stops 4rd, and cam mechanism 42.

The time-driven member 3i?, which is presently a gear disc and for convenience referred to hereinafter as the time gear, is driven by a pinion 44 which, in turn, is driven by a constant-rate prime mover, conveniently a synchronous motor (not shown), either directly or through intermediation of suitable reduction gearing in a casing 46. Hence, the time gear 36 is driven at a constant rate whenever the prime mover is running. The time gear 30 is, in the present instance provided with a hub 48 which is journalled on a shaft Sit that is journalled with its ends in the opposite end plates 225 and 24 (Fig. 3).

The escape member --2, being presently iu the form of a disc, is provided with a peripheral shoulder 32 and also with a slot 54 through which the shaft 59 extends fittedlv so that the escape member is turnable about the axis of this shaft and is also guided for bodilv movement, within limits, radially thereof (Figs. 3 The escape member 32, which is axially .retained on the shat t Stl between a collar form-ation Se thereon and the time gear 36', is adapted intermittentiy to advance unidirectionally, with a snap action, into successive positions in which its shoulder 52 rests against successive stops 4i) for a predetermined time interval. Tl ere'being in the present example two of these stops di) which are arranged diametrically opposite each other with respect to the shaft axis x-x (Fig. 4), it stands to reason thatv the escape member 32 will be advanced in equal intermittent steps of 180 degrees. The stops 4i) are, in the present instance, provided with shanks 58 (Fig. l) by means of which they are firmly mounted in the end plate 22. These stops 40 are accurately spaced equal distances from the shaft axis x-x.

The necessary torque for the intermittent advances of the escape member 32 is derived from the earlier mentioned spring 34, while the aforementioned cam mechanism 42 acts bodily to shift the escape member for periodic release of its shoulder 52 from each stop 49 and quick alignment of the same with the next stop against which it springs with a snap action. To this end, the torsion spring 34, being presently of the cylindrical helical type,` is interposed between the escape member 32' and the time gear 3l), not directly but advantageously through intermediation of the output element 36 for a reason which will appear obvious hereinafter. Thus, the spring 34 surrounds the hub 43 of the time gear 3l) and is anchored with its ends 6l! and 62 on posts 64 and 66 on the time gear Eil and on a disc 68 on the output element 36, respectively, of which the latter is firmly mounted on the shaft 5t? and is, in the present instance, a pinion in permanent mesh with a gear disc 79 on a shaft 72 that may be the driver of a control or any other device, such asy timer-switch mechanism, for instance, which is to be operated and controlled by the present escapement. The spring 34 is preloaded so as normally to urgev the output pinion 36 in a countercloclrwise direction (Fig. 2). relative: to the time gear 3l) which, by its described motor drive or any other suitable means, is prevented from backing in the opposite or clockwise direction. The spring force acting on the output pinion 36 is imparted toI the escape member 32 through the earlier mentioned driving connection 38 which, besides the shaft 50, further includes a transverse key '74 on the latter which is received with a sliding tit in the slot S4 in the escape member.

The cam mechanism d?, comprises, in the present instance, two cam rises 76 and Tilv which are presently provided on the peripheral edge of the escape member 32 (Figs. 4 and 5), and a follower pin lll) which is carried by the time gear Sil.

Assuming now that the motor for the drive of the time gear 3l) is running and that the escape member 32k and follower pin Sil are presently in their respective full-line positions in Fig. 4 in which the shoulder S2 on the escape member 32 has just come to rest against the stop 44M, it then. follows that the escape member will remain in this temporary rest position while the time gear 30 conti-nues to rotate, counterclockwise as viewed in Fig. 4, and the follower pin 8l) thereon rides past the cam rise 78 on the escape member and into the dotted-line position Sila. When the follower pin reaches the position 80a (Fig- 4.) the same will, on continued rotationof the time gear 30, begin to cooperate with the cam rise 76 on the escape member 32 and gradually shift the latter bodily from the full-line position into the dot-and-dash-line position in which its shoulder 52 is about to clear the stop Lilla, the follower pin fill having by then reached the dot-and-dashline position Silk (Fig. 4). While the pin 80 on the time gear 30 thus travels through one-half revolution from its full-line position to its dot-and-dash-line position 80h, the spring 34 is reloaded or rewound, this by virtue of the fact that during this time period the time gear 3l) is driven while the output pinion 36 is held against rotation due to the engagementof the shoulder 52 on the escape member 32 with the stop 40a (Fig. 4).

0n the slightest continued travel of the follower pin 80 on the time gear Sil from its dot-and-dashline position 80h (Fig. 4) into its full-line position 80C (Fig. 5), the shoulder 52' on the escape member 32 will clear the stop 40a, and the escape member will thus be releasedk for an 6 intermittent advance through 180 degrees against the other stop 4Gb (Fig. 5') under the urgency of the spring 34. The output pinion 36, of course, participates in this spring-advance of the escape member 32 through 180 degrees and, accordingly,y indexes the control shaft 72 through a smaller anngle due to the exemplary reduction character of the pinion 36 and gear disc 70. While the escape member 32 and output pinion 36 are thus quickly spring-advanced through 180 degrees, the follower pin 011 the continuously driven time gear 30 will hardly ad- Vance to any noticeable extent beyond the full-line position 80e (Fig. 5 with the result that the same cooperates with the cam rise 78 on the released escape member to cause a bodily shift of the latter so as to bring its shoulder 52 into full operative alignment with the stop 4Gb by the time the escape member reaches the position in Fig. 5. Of course, while the spring 34 will be partly unwound when impelling the escape member 32 and output pinion 36 through 180 degrees, the same will be rewound to its full preload condition while the shoulder 52 on the escape member rests against the stop 4Gb (Fig. 5) and the time gear 30 continues to be driven. As soon as the escape member 32 reaches the position in Fig. 5, the follower pin on the time gear Sil will gradually advance from its position e past the cam rise 7S on the escape member and in time cooperate with the cam rise 76 thereon in bodily shifting the escape member for the release of its shoulder 5-2 from the stop 4Gb and another intermittent spring advance of the escape member through another degrees, this time against the stop 40a. The escape member 32,. and hence also the output pinion 36, are thus spring-advanced in steps of 18() degrees and intermittently stopped for rest intervals of equal duration, and the. control shaft 72 is accordingly indexed.

It appears from the foregoing description of the instant escapement 20 that the same achieves the aforementioned important objectives of simplicity of construction which permits its highly efficient mass production at very low cost, and of highly accurate and reliable perfonnance for the longest time even despite considerable tolerances in size or shape of its operating parts.

While in the described escapement 20 the contact pressure between the shoulder 52 on the spring-loaded escape member 32 and each stop 40 engaged thereby is relied on to prevent release of the former from the latter, under shock or vibration, for instance, while the follower pin 80 on the time gear 30 is in any angular position in which it doesA not lock the escape member against such release, the escape member 32 of the modified escapement 20a of Fig. 6 is yieldingly held in engagement with each stop 40 by means of aI compression-type spring 90 which is received in the slot 54a in the escape member and interposed between an. endwall 92 thereof and the adjacent end of the transverse key 74a on the shaft 50a. The escape member 32a will thus effectively resist unauthorized release from either stop 40', under vibrational or shock forces, for instance, not only with the considerable static friction between its shoulder 52a and the stop engaged thereby, but with the additional force of the spring 90.

Still greater assurance against unauthorized release of the escape member 32b from either stop 40" of the modified escapement 20b of Figs. 7 and 8 is afforded by providing the escape member with a cam slot 96 with which the follower pin 80 on the time gear 3)b cooperates. The cam slot 96 has a part-circular portion 96a which is disposed concentrically with respect to the axis of the shaft 50B when the escape member 32h rests with its shoulder 52b against either stop 40 to the desired full extent, and a continuing portion 96h which slants outwardly away from the slot portion 96a. Thus, with the escape member 32h in the exemplary full-line position in Fig. 7 in which its shoulder 52b rests fully against the stop 40a",l the follower pin 80 is shown in a full-line position. in which it will, on its continued clockwise rotation with the time gear 30b, cooperate with the slanting slot portion 96b and cam the escape member into its dotted-line position (Fig. 7) in which its shoulder SZb is about to clear the stop 40a. At that time, the follower pin has reached the dotted-line position 80a. On the slightest further advance of the follower pin beyond its dotted-line position 80a in Fig. 7 into the position shown in Fig. 8, the escape member 32b will be released from the stop 40a and be spring-urged, clockwise, from the dotted-line position in Fig. 7 into the position in Fig. 8 in which its shoulder 52h bears against the stop 40h". During this spring-advance of the escape member 3217, the slanting slot portion 96b therein will cooperate with the follower pin 80 in its position in Fig. 8 and bodily shift the escape member into alignment with the stop 40h, while the part-circular slot portion 96a will cooperate with the follower pin in retaining the escape member in alignment with the stop 40h until its shoulder 52b comes to rest thereagainst. On continued rotation of the follower pin 30 with the time gear 302) from the position shown in Fig. 8, the former wili cooperate with the cam slot 95 in locking the escape member against unauthorized release from the stop 40h, under vibrational or shock forces, for instance, until its accurately timed release from this stop is achieved on cooperation between the `follower pin and the slanting slot portion 96b, as will be readily understood.

While the previously described forms of the escapement are provided with two examplary stops for intermittent advances of the escape member through 180 degrees, the escapement of the present type is quite versatile in achieving intermittent advances or steps of the escape member through angular distances which are larger or smaller than 180 degrees. Thus, the escapement 20c in Figs. 9 and 10 is provided with six stops 100, so that the escape member 32e is spring-advanced in steps of 60 degrees. The cam mechanismfor the periodic release of the escape member from successive stops and its alignment with each stop against which it advances, comprises peripheral cam edges 102 and 104 on the escape member 32C and two spaced follower pins 106 and 10S o'n the time gear 30C. Assuming that the escape member 32C is presently in the full-line position in Fig. 9, in which it rests against the stop 100e, the pin 106 will in its counterclockwise travel with the time gear Stic reach the full-line position in Fig. 9 and thereupon cooperate with the cam edge 102 on the escape member 32C in bodily shifting the latter into the dotted-line position in which the same is about to be released from the stop 10051 for a spring-advance against the next stop 100b. The pins 106 and 103 have by this time reached the respective dotted-line positions 10611 and 108a (Fig. 9), and the escape member 32C will be released from the stop 1001i and spring-advanced against the next stop 100b on the slightest further advance of the pins into their positions 10611 and 101% (Fig. l0). During this springadvance of the escape member 32C against the stop 10011, the cam edge 104 on the escape member will cooperate with the pin 108, in its position 10Sb in Fig. l0, in bodily shifting the former into alignment with the stop 100b. On continued rotation ofthe time gear 30e the pin 106 will move toward the cam edge 102 on the escape member and in time cooperate with the same in bodily shifting the latter for its release from the stop 10011 and springadvance against the next stop 100C, while the pin 108 will in the meantime move away from the cam edge 104 so as to permit the next release of the escape member from the stop 100e, and will have reached a position in which to cooperate with the cam edge 104 in bodily shifting the escape member into alignment with the next stop 100C by the time the escape member is released from the stop 10012 and spring-advanced against the stop 100C. The escape member is thus periodically advanced in intermittent steps of 60 degrees, and the pins 106 and 10S alternately cooperate with the cam edges 102 and 104 on the escape member in releasing the latter from each stop and aligning it with the next stop against which it is spring-advanced. i

While in the escapement 20e just described the escape member is advanced in steps of 60 degrees, this by virtue of the provision of six stops, it stands to reason that a similar escapement could be provided with twelve stops, for example, in which case the escape member would be advanced in steps of 30 degrees, the cam edges on the escape member and therelative disposition of the two follower pins on the time gear being, of course, modified in an obvious manner for the 30 degree stepping of the escape member.

Figs. 11 and 12 show a further modified escapement 20d which is in all respects like the escapement 20c of Figs. 9 and 10, except that a single follower pin 112 on the time gear 30d cooperates with a cam slot 114 in the escape member 32d in periodically releasing the latter from the stops and aligning it with each next stop against which it is spring-advanced. r1`hus, with the escape member 32d presently in the full-line position shown "n Fig. 11, in which it has just come to rest against the stop 10011', the pin 112 on the time gear 30d will advance from its full-line position, counterclockwise as viewed in Fig. 1l, and in time cooperate with an inwardly spiralling end length or portion 114:1 of the cam slot 114 in bodily shifting the escape member into the dotted-line position in which it is about to be released from the stop 100er. The pin 112 has by this time reached the dottedline position in Fig. 1l, and will, ou its slightest further advance into the position shown in Fig. 12, cause release of the escape member from the stop 100a for its springadvance against the next stop 1005. During this springadvance of the escape member, the spiral portion 114a of the cam slot 114 therein will iirst cooperate with the pin 114, in its position shown in Fig. l2, in bodily shifting the escape member into alignment with the stop 100b, while the remaining concentric portion of this cam slot will cooperate with the pin 114 in retaining the escape member in alignment with the stop 100b' until it comes to rest thereagainst (Fig. 12). The pin 112 on the time gear 30d thus cooperates with the cam slot 114 in the escape member 32d in periodically releasing the latter from successive stops 100 and shifting it into alignment with each stop against which it is spring-advanced.

Fig. 13 shows a further modified escapement 20e the escape member 32e of which is spring-advanced in intermittent steps of 360 degrees. To this end, the present escapement is provided with a single stop 118, and the escape member 32e is normally urged by a spring 120 into a position in which its shoulder 52e is in operative alignment with the stop 1115. The spring 120, which is presently of the compression type, is received in the slot 54e in the escape member 32e and interposed between an endwall 122 of this slot and the adjacent end 124 of the transverse key 74e on the shaft 50e. The time gear 30e carries in this instance a depending lug 126 which, on engagement with a similar upstanding lug 128 on the escape member 32e, bodily shifts the latter, against the force of the spring 120, for release of its shoulder 52e from the stop 118 and a spring-advance of the escape member, through 360 degrees,-into reengagement with the stop 118, the spring acting during this springadvance of the escape member bodily to shift the latter for realignment of its shoulder 52e with the stop, as will be readily understood. When the shoulder 52e on the escape member comes to rest against the stop 118 at the end of each intermittent spring-advance of the former through 36() degrees, the lug 126 on the time gear 30e is ahead, counterclockwise as viewed in Fig. 13, of the lug 128 on the escape member 32e, so that the lug 126 will never interfere with the spring-advance of the released escape'member through the full 360 degrees.

While in the previously described forms of the present escapement the follower pin or pins are carried by the 9 time gear and the cam means are provided on or in the escape member, it is, of course, entirely feasible to provide the follower pin or pins on the escape member and the cam means on or in the time gear. Thus, Figs. 14 and 15 show an escapement 201 in which the time gear 30]c carries a cam disc 130, while the escape member 32f carries a follower pin 132. In Fig. 15, the escape member- 32) is shown in a momentary full-line position in which its shoulder 52f is about to be released from the stop 134 for a spring-advance of the escape member, counterclockn wise, through 180 degrees, i. e., into the dot-and-dash-line position (Fig. 15) in which its shoulder rests against the other stop 136. rThe escape member 32]c has been bodily shifted from a position in which its shoulder 527 is in full engagement with the stop 134 into the full-line position in Fig. l5, on cooperation between the follower pin 132 on the escape member and the rising lobe 138 of the cam disc 130 on the time gear 303 while the latter is driven counterclockwise as viewed in Fig. l5. On slight further advance of the cam disc 13th with the driven time gear 30f beyondy the angular position shown in Fig. l5, the pin 132 on the escape member will reach the crest 140 of the rising lobe 138 of the cam disc 130, with the result that the escape member will be released from the stop 134 and spring-advanced through 180 degrees against the other stop 136. In being thus springadvanced, the escape member 32f will carry the follower pin 132 into the dot-and-dash-line position in Fig. 15. When the pin 132 is thus carried into its dot-and-dash-line position, it is urged to ride down the lobe 13S and along the continuing inner dwell 142 of the cam disc 130 by the interposed spring 144 between the transverse key 74f on the shaft 50i and the escape member 32], with the result that the shoulder 52f on the latter is brought into alignment with the stop 136 before engaging the same. On continued rotation of the time gear 30f with the cam disc 130 from the position shown in Fig. 15, the lobe 138 on the cam disc will in time cooperate with the follower pin 132 in its dot-and-dash-line position and release the escape member 32)c in its dot-and-dash-line position from the stop 136 for its next spring-advance against the stop 134, as will be readily understood.

Fig. 16 shows another modified escapement 20g which is in all respects like the escapement 20) of Figs. 14 and 15, except that the follower pin 132' on the escape mer-1- ber 32g projects into a cam slot 150 in the time gear 30g. The pin 132 has been moved to its full-line position, in which the escape member 32g is about to be released from the stop 152, on cooperation with the outwardly slanting end length or portion 150av of the cam slot 150 during preceding counterclockwise rotation of the time gear 30g. On slight further counterclockwise rotation of the time gear 30g and its cam slot 150, the slot portion 150:1 and follower pin 132' will cooperate to release the escape member 32g from the stop 152 for its spring-advance into the dot-anddashline position in which it rests against the other stop 154, the cam slot 150 and follower pin 132 cooperating during this spring-advance of the escape member bodily to shift the same into alignment with the stop 154, as will be readily understood. The follower pin 132 and cam slot 150 thus cooperate in periodically releasing the escape member from each stop and aligning it with the next stop against which it is spring-advanced.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

What is claimed is:

1. In an escapement, the combination with a shaft and a plurality of stops arranged peripherally throughout about the shaft axis and spaced equiangularly from each other and equal distances from said shaft axis, of a first time-driven member on said shaft turnable about the axis thereof; an escape member having a shoulder and a rectilinear' slot through which said shaft extends fittedly so as to be turnable about the axis thereof and also guided for bodily movement radially thereof; anchor means on said members, respectively; a preloaded spring secured with its opposite ends to said anchor means, respectively, and normally urging said escape member in the drive direction of said first member; a cam disc with a cam periphery and pin means on said members, respectively, and cooperating bodily to retract and advance said escape member for disengagement of said shoulder from each stop on which it rests and for its operative alignment with each next stop toward which it springs, respectively; and an output element turnable about said shaft axis and drivingly connected with said escape member for rotation therewith.

2. In an escapement, the combination with a shaft and more than two stops arranged peripherally throughout about the shaft axis and spaced equiangularly from each other and equal distances from said shaft axis` of a first time-'driven member on said shaft turnable about the axis thereof, an escape member having a shoulder and a rectilinear slot through which said shaft extends fittedly so as to be turnable about the axis thereof and also guided for bodily movement radially thereof; anchor means on said members, respectively; a preloaded spring secured with its opposite ends to said anchor means, respectively, and normally urging said escape member in the drive direction of said first member; a cam disc with a cam periphery and two pins on said members, respectively, of which said cam disc and one pin cooperate bodily to re tract said escape member for disengagement of said shoulder from each stop on which it rests, and said cam disc and the other pin cooperate bodily to advance said escape member for operative alignment of said shoulder with each stop toward which it springs; and an output element turnable about said shaft axis and drivingly connected with said escape member for rotation therewith.

3. In an escapement, the combination with a journalled shaft and more than two stops arranged peripherally throughout about the shaft axis and spaced cquiangnlarly from each other and equal radial distances from said shaft axis, of a first time-driven member freely turnable on said shaft; an output element mounted on said shaft; a transverse key on said shaft; an escape member having a shoulder and a rectilinear slot in which said key is received with a sliding fit so that said escape member is turnable about said shaft axis and guided for bodily movement radially thereof as well as drivingly coupled with said output element; a preloaded helical torsion spring about said shaft anchored with its opposite ends to said first member and output element, respectively, and normally urging the latter in the `drive direction of said first member; a cam formed by a peripheral margin of said escape member; and two pins on said rst member of which one pin cooperates with said cam bodily to retract said escape member for disengagement of said shoulder from each stop on which it rests and the other pin cooperates with said cam bodily to advance said escape member for its operative alignment with each next stop toward which it springs, respectively.

References Cited in the file of this patent UNITED STATES PATENTS 644,745 Marshall Mar. 6, 1900 735,317 Tregoning Aug. 4, 1903 1,427,312 Miller Aug. 29, 1922 1,479,970 Leppert Ian. 8, 1924 2,762,884 Van Eyk Sept. 11, 1956 2,810,302 James et al Oct. 22, 1957

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