US3287897A

US3287897A - Timepiece escapement

Info

Publication number: US3287897A
Application number: US477205A
Authority: US
Inventors: Johnson Harold Alec
Original assignee: AMF Inc
Current assignee: AMF Inc
Priority date: 1965-08-04
Filing date: 1965-08-04
Publication date: 1966-11-29
Anticipated expiration: 1983-11-29

Description

Nov. 29, 1966 H. A. JOHNSON 3,287,897

TIMEPI ECE ESCAPEMENT Filed Aug. 4, 1965 5 Sheets-Sheet l INVENTOR HAROLDAJOHNSON Nov. 29, 1966 H. A. JOHNSON 3,287,897

TIMEPIECE ESCAPEMENT Filed Aug. 4, 1965 i5 Sheets-Sheei 2 HAROLD JOHNSON ,uw TORN Nov, 29, 1966 H. A. JOHNSON TIMEPIECE ESCAPEMENT .3 Sheets-Sheet Filed Aug. 4, 1965 INVENTOR HAROLD JOHNSON United States Patent O 3,287,897 TIMEPIECE ESCAPEMENT v Harold Alec Johnson, Los Angeles, Calif., assignor to American Machine & Foundry Company, a corporation of New Jersey Filed Aug. 4, 1965, Ser. No. 477,205 10 Claims. (Cl. 58-116) This invention relates to movements for clocks and watches, and in particular to escapement mechanisms for use in the same.

The escapement mechanism as it exists in clocks and watches is a major cause of their inaccuracy and high cost of manufacturing. This results chiefly from the close dimensional requirements and the necessity for adherence to close tolerences especially with regard to the distance between axis of the escapement wheel and the axis of the escapement pawl.

It is therefore the main object of the invention to provide an escapement mechanism which eliminates the need for adherence to close tolerances and permits considerable departure from conventi-onal dimensional requirements without sacrificing the accuracy of the watch.

Another object of the invention is to provide an escapement mechanism having an escapement dog which is selectively movable or adjustable in relation to the escapement axis.

Still another object of the invention is to provide an escapement mechanism having means to increase or decrease .the resistance in the movement of the escapement dog towards the escapement wheel.

A still further object of the invention is to provide a clock or watch which is relatively simple and inexpensive to assemble and to manufacture without sacrice of accuracy or durability. A

These and other objects of the invention, as well as, certain features of novelty and advantages will be apparent from the following description of an exemplary embodiment.

In the accompanying drawings illustrating the embodiment of the invention:

FIG. 1 is a front elevation of a stop watch incorporating the invention;

FIG. 2 is a top View of the same, taken on line 2 2 of FIG. l;

FIG. 3 is a sectional rear view of the stop watch with the cover removed to illustrate its components;

FIG. 4 is a partial sectional side elevation taken on line 4 4 of FIG. 3;

FIG. 5 is also a partial sectional side elevation taken on line 5 5 of FIG. 3, illustrating the escapement mechanism on an enlarged scale;

FIG. 6 is another sectional side elevation taken on line 6 6 of FIG. 3;

FIG. 7 is an exploded view of the main drive gear and its clutch mechanism;

FIG. 8 is a partial sectional view of the escapement mechanism, taken on line 8 8 of FIG. 5, illustrating the action of the escapement dog in conjunction with the escapement wheel, and;

FIG. 9 is a partial sectional view, similar to FIG. 8, illustrating a modified form of an adjustable escapement mechanism.

It should be understood at the outset that the present invention has application in a wide variety of clock or watch movements as well as in related timing mechanisms. However, for the sake of brevity only, the presrice ent invention will be shown and described in connection with a stop watch. This example has been chosen since its principles and concepts may be clearly observed.

Now with reference to the drawings, stop watch W consists of an outer casing or covering 10 in which is enclosed an inner housing 12 supporting and containing the various clockwork components. As is common, the casing 10 and inner housing 12 are formed generally of a front shell or face and a rear shell or back. The parts of ythe inner housing 12 are held together and spaced by a plurality of spacer screws 50. The outer covering 10 has a front transparent face 18 and a back which is clipped inconventional fashion to the housing 12. The watch W is provided with a stem or knob 20 normally situated at the 12 oclock position.

With specic reference to FIGS. 3 5, the clock-work mechanism for driving the watch includes the knob 20 which is secured to the top end of a suitably shaped stem plate 22, .the upper end of which projects through cutout portions 24 formed in the front and rear shell of the inner housing 12, as well as in the watch case 10. The lower end of plate 22 terminates in a hub` 26 rotatably supported by a transverse shaft or pin 28, which is pivotally mounted in suitably formed bearings in the front and rear wall of the inner housing 12. Adjacent to the hub 26 of stern plate 22 and, also, loosely supported by the shaft 28, there is located a gear sector 30 which engages with a pinion gear 32 (FIG. 3). The gear sector 30 is provided with an extension arm 34 having a boss 36 carrying two spaced, horizontally projecting pins 38 (FIGS. 3 and 4). A torsion spring 40, constituting the main spring of the stop watch W, is wound loosely around the hub 26. One end of the spring 40 is lodged between the projecting pins 38 and the other end of said spring is lodged against a stationary pin 42 which is integral with and projecting horizontally from the inner side of the front wall of the housing 12. In addition, housing 12 is provided with two additional pins 44 and 46 which are similar to pin 42 and which are spaced apart from pin 42 and from each other so that the stationary end of the spring 40 can be lodged against either of the three pins and thus provide means for adjusting the tension lof said spring 40.

Midway along the stem plate 22 is hooked one end of a tension spring 48, which has its other end anchored to one of the spacer screws 5l) separating the parts of the housing 12. The tension spring `48 serves the purpose of keeping the stem 2G and plate 22 in the normal upright l2 oclock position and returning it to this position after it has been cocked during winding operation which will be described hereinafter.

The indicator assembly and drive mechanism powered by the main spring `assembly previously described is shown clearly in FIGS. 6 and 7. Engaging with the gear sector 3) is a small pinion gear 32 fixed concentrically to one face of a clutch disc 52. The other face of the clutch disc 52 is provided kwith a plurality of radial teeth 54, .as illustrated in FIG. 8. The clutch disc 52 is iixed on a stepped shaft 56 projecting from both faces of the disc. Each end -of shaft 56 is rotatably supported in suitable bearings means provided in the front and rear inner faces of the housing 12. Adjacent to clutch disc 52 and loosely supported on the stepped shaft 56, is situated -a gear 58 having a plurality of peripheral teeth. In addition, one face of gear 58 is provided with a recess or shoulder 60 (FIG. 8) which is further provided with a plurality of radial teeth 62 arranged in such a manner as to engage with and co-operate with the radial teeth 54 on the face of clutch disc 52 when gear '58 is made to abut the disc 52. A collar 64 is fitted adjacent the other and smooth face of the gear 58 and is also loosely supported by the stepped shaft 56. The collar 64 is formed of a yieldable material such as sponge rubber or felt. A washer 66 completes the assembly mounted on the stepped shaft 56 and acts as the spacer between the collar 64 and the inner side of the housing 12. The front end of shaft 56 protrudes through the housing 12 and carries the indicator hand 16.

In operation, the watch W is wound by simply moving the stem 20 in a counterclockwise direction as indicated by the arrow D to the dotted line position of FIG. 4 and then releasing the same. The movement of stem 20 is imparted to the gear sector 30 effecting a vwinding of the spring 40, through the engagement of the stem plate 22 on the side edge 116 of boss 36 on the arm extension 34. Since gear sector 30 meshes with gear 32, which in turn is fixed on shaft 56, the anticlockwise rotation imparted to sector 30 effects a rotation of the shaft 56 thus carrying the indicator hand 16 to its zero position.

Thus far, there has been described a simple clockwork movement sufficient to illustrate the construction of and function of the escapement of the present invention. For this purpose, reference is now made to FIGS. 3, 6, 8 and 9.

In FIG. 3 it will rbe seen that the peripheral teeth of the main gear 58 mesh with a pinion 68 which is fixed to a larger gear 70. Both gears -68 and 70 are Ifixed on a shaft 72 which is rotatably supported in suitable bearings means provided in the front and rear faces of housing 12. Gear 70 meshes with still another pinion gear 74 fixed on a shaft 76 on which is fixed still another wheel `78 which comprises the escapement wheel of the present mechanism. The shaft 76 is also rotatably supported at both ends in suitable bearing means provided in the front and rear inner faces of the housing 12. The escapement wheel 78 comprises an inner peripherally geared member 80 and a concentric internally geared ringing member 82 surrounding gear 80 and coplanar therewith in the fashion of a sun and ring gear assembly. As illustrated in FIGS. 3 and 6', the peripheral teeth of gear 80` and the opposing teeth of ring gear 82 face each other with the apexes of one general-ly opposed to the valleys of the other and are so arranged as to provide an annular narrow path 81. Within path 81 there projects an escapement dog o1 finger 84. As shown in this embodiment, the escapement wheel, i.e. its two ring members are formed as one piece; however, as noted later, this is only one form and may be conveniently fashioned of two or more pieces relatively fixed for unitary rotary movement.

Projecting escapement dog 84 is formed as part of a movable escapement drum 86 mounted on a central stem or shaft 88, rotatably suported in a bearing boss 90 on the inner surface of rear face of housing 12, and which acts as a fulcrum point for the drum 86. The front face 92 (FIG. 5) of the boss 90 engages with the inner face of drum 86 and acts as retainer and an additional 'bearing for the latter. The escapement dog 84 projects parallel to the axis 76 of the escapement wheel 78 from the front face of drum 86 which is substantially parallel to the plane of the escapement wheel 78. The dog 84 is situated eccentrically with respect to the fulcrum shaft 88 thus being able to oscil'late freely between the teeth of

gears

80 and 82. In order to give better oscillating performance, the drum might as shown be provided with an outer metal ring 96 for added weight.

It will be obvious that in operation, so long as the escapement drum 86 is free t-o move, i.e, oscillate and the escapement wheel 78 is driven through the clockwork movement, the projecting dog 84 will cause the controlled and timed rotation of the escapement wheel 78 and consequently, that of the main gear 58 and hand 16.

The stop watch W is also provided with a start and stop lever 100 which projects from an elongated slot 102 in the watch case (FIG. 3) and is integral with an arcuate guide flange 104, which is slidably confined in the peripheral lspace between the case 10 and housing 12. A curved lug 106 projects from the lower side of flange 104 through a suitable slot in housing 12 and is provided with an arcuate tail 108. The free end of the tail 108 is formed into a stop lug or shoulder 110. Lug 106 is also provided with a shaped hump 112 which engages the free end of a flexible lock lever 114 projecting from and secured to one of the transverse spacer screws 50.

In viewing FIG. 3 of the drawings, it is self-evident that when the lever is moved in a clockwise direction, the stop lug 100 wedges itself between the inner peripheral wall of housing 12 and the periphery of the escapement drum 86, as illustrated in FIG. 3', and thus effecting a locking of the latter and preventing any movement 0f the same.

When lever 100 is moved in a counterclockwise direction, as indicated by the arrow S, the stop lug is caused to ydisengage from the escapement drum 86, the latter can then oscillate when urged by the escapement dog 84 and wheel 78. The flexible lock lever 114 is employed 'for the purpose of holding the lever 100 firmly in either the locked or unlocked position.

Because gear 32 is connected to the remainder of the watch gearing through the ratchet-like

clutch gearing members

52 and 58, operation of the watch is prevented so long as the stop lever 100 is in locked position. Of course, the clutch mechanism permits the return of stem 20, since after the stem 20 is pushed in counterclockwise direction to the end of the slot 24 as shown in dotted lines in FIG. 3, it automatically snaps back and returns to its 12 oclock position due to the action of the tension spring 48 attached to the stem plate 22. To prevent undesired play and give greater sta-bility to the stern plate 22 during winding operation, the latter is provided with a ringshaped arcuate guide lug 118 which is concentric with the pivot point of said stem plate and slidingly engages with the inner `side of the peripheral portion of the housing 12.

In the escapement mechanism illustrated on an enlarged scale in FIG. 8, the escapement dog 84 has the shape of a diamond having four equal straight sides and having two angles between them acute -and two obtuse. This shape has been found convenient. However, as will be seen in FIG. 9, it is by no means to be understood as being the only shape. It has been observed that dogs or fingers having round or oval cross-sectional shapes, as well, are sufficiently successful. FIG. 8 furthermore illustrates that the angles of the teeth of the ring gear 82 and the peripheral teeth o-f the gear 80 of the escapement wheel 78 may be substantially the same and that the distance of the axis of the shaft 88 of the carrier drum 86 and the escapement dog 84 is predetermined and fixed.

Notwithstanding this, the slope and pitch of the teeth are not critical and may vary along with the shape of the dog. This, of course, gives emphasis to one of the chief advantages of the present invention, that is, the dimensional limits of gear or dog are not critical thus enabling clock movements to be made easily and more cheaply than heretofore. Another advantage lies in the fact that by being able to vary these factors, a watchmaker may readily choose his timing Without being overly concerned with the criticality of his components.

In a modified embodiment of the escapement mechanism illustrated in FIG. 9, another heretofore unknown feature can be seen in the design which permits various settings of the escapement dog 120 relative to the laxis or fulcrum pin 122 of the carrier member 124, in the case an oval arm-shaped member, on which the said dog is fixed. The arm 124 which, of course, replaces the dog carrying drum 86 shown in FIG. 7, is provided with a plurality of spaced and longitudinally aligned holes 126, any one of which may be engaged with the fulcrum pin 122 permitting shifting of the .axis of the arm 124 towards or away from the escapement dog 120 so that when the dog is engaged with and moved by the

teeth

128 and 130 of the escapement wheel 132, greater or lesser resistance may be generated. When the axis of the escapement arm 124 is brought closer to the escapement dog 120, it requires greater energy on the Ipart of the escapement wheel to move sai-d dog to and fro and thus effects a slower movement of the escapement wheel 132 and consequently of the watch mechanism. When the distance -of the axis of the arm 124, relative to the dog 120, is increased, the swinging angle of the latter is decreased and it takes less energy to move the same which in turn results in a faster movement of the escapement wheel and the therewith converted watch mechanism. It can be readily seen that this arrangement makes it possible to design an angle escapement mechanism adaptable for a number of predetermined timings and specific applications.

In both the embodiment shown in FIGS. 8 or 9, it will be observed that the fulcrum axis of the carrier member is parallel to the axis of the escapement wheel and it intersects the plane of the escapement wheel within the space or area :between the teeth of the gear members. This facilitates oscillation of the dog or finger.

In conventional escapement mechanisms, the dimensional limits between, for example, the axis shaft 88 of the escapement drum 86 and the axis shaft 70 of the escapement wheel 78 are extremely critical and require the observance of a close tolerance, the present invention entirely eliminates this need and permits slackening of this dirllensional requirement to a degree not heretofore poss1 e.

The embodiments of the present invention as shown in the drawings are merely illustrative. Many other forms, all within the scope of the present invention, can be fashioned for both the coplanar escapement wheel assembly and/ or escapement dog. These embodiments will seem obvious now that the concept has been taught, nevertheless, the inner and outer coplanar gear members can be molded in integral forms, Ias shown, or machined, stamped or assembled of separate parts in either metal or plastic. The escapement dog may also take various shapes including round, oval, square or multilateral. As to the teeth on the gear members, their shape may take various forms, (as shown) either having acute or more obtuse angles, sharp or flat top etc. It is seen apparent that one or more of the elements, (dog, teeth, etc.) may be varied, the only criterion to be concerned with being the over-all geometry permitting the dog to oscillate between the teeth at a predetermined timing.

It will also be `apparent that the present invention need not be confined to use in stop watch (as described for illustration) but in any watch movement.

While we have shown the invention in the best forms known to us, it will nevertheless be understood that this is purely exemplary and that modifications in the construction, arrangement and combination of parts and the substitution of equivalents, mechanically and otherwise, may be made without departing 'from the spirit of the invention, except as it may be limited in the appended claims.

What is claimed is:

1. A timing escapement mechanism comprising a pair of coplanar spaced concentric gear members one of which comprises a wheel gear having a plurality of peripheral teeth and the other of which comprises a ring gear having a plurality of internally facing teeth, and a dog located between the inner and outer gear members adapted to oscillate between said teeth.

2. A timing escapement mechanism comprising a pair of driven coplanar concentric gear members one of which comprises a wheel gear having a plurality of peripheral teeth andthe other of which comprises a ring gear having a plurality 4of internally facing teeth, and a freely pivotal follower dog located between the inner and outer gear members adapted to oscillate between the teeth of said two driven gear members.

3. A timing escapement comprising a pair of relatively fixed coplanar concentric gear members one of which comprises a wheel gear having a plurality of peripheral teeth and the other of which comprises a ring gear having a plurality of internally facing gear teeth, said relatively fixed gear members being as a unit freely rotatable about a fixed axis and a driving dog located between the inner and outer geant members, said dog being adapted to oscillate between the teeth thereof, and drive means for oscillating said drive dog thereby causing said relatively fixed gear members to effect a periodic rotary movement about its fixed axis.

4. In a clock or watch movement, an escapement mechanism comprising a pair of relatively fixed annularly spaced coplanar concentric gear members one of which comprises a wheel gear having a plurality of peripheral teeth and the other of which comprises a ring gear having a plurality of internally facing gear teeth, said relatively fixed gear members being as a unit rotatable about their common central axis, and a dog located within the annular space between said gear members, said dog being pivotally mounted to oscillate between the teeth of said gear means, and means co-operating with said clockwork movement for driving either said gear members or said dog to thereby effect a periodic rotary movement of said gear members.

5. In a clock or watch movement, an escapement mechanism comprising a pair of relatively fixed annularly spaced coplanar concentric gear members one of which comprises a wheel gear having a plurality of peripheral teeth and the other of which comprises a ring gear having a plurality of internally facing gear teeth, said relatively fixed gear members being as a unit Irotatable about their common central axis, and a follower dog located within the annular space between said gear members, said dog being mounted to pivot about an axis remote from said dog, and means co-operating with said clockwork movement for driving either said gear members or said dog to thereby effect a periodic rotary movement of said gear members.

6. In a clock or watch movement, an escapement mechanism comprising a pair of relatively fixed annularly spaced coplanar concentric gear members one of which comprises a wheel gear having a plurality of peripheral teeth and the other of which comprises a ring gear having a plurality of internally facing gear teeth, said relatively fixed gear members being rotatable as a unit about their common central axis, and a follower dog located within the annular space between said gear members, said dog being pivotally mounted to pivot about an axis remote from said dog, means for selectively varying the distance between said dog and the pivot axis, and means co-operating with said clockwork movement for driving either said gear members or said dog to thereby effect a periodic rotary movement of said gear members.

7. In a clock or watch movement an escapement mechanism comprising a wheel member rotatably mounted about its central axis, said Wheel member having formed in one face thereof a pair of spaced concentric gear members, one of said gear members having a plurality of peripheral teeth, the other of said gear members having a plurality of linternal teeth opposing those of said one member, carrying means located adjacent said one face of said wheel member, nger means projecting from said carrier means into the space between the teeth of said gear members, said carrier means being pivotably mounted about an axis parallel to the axis of said wheel member to permit said finger to move within the space between said gear members, means for driving either said wheel member or said carrier member to effect periodic rotary movement and oscillation of said finger.

8. The mechanism in accordance with claim 7, wherein said carrier means comprises a second wheel member disposed in a plane parallel to the plane of'the first wheel member and is pivotable about its central axis, the projecting finger being located in a position radially remote from said central axis and substantially parallel thereto. References Cited by the Examiner 9. The mechanism in accordance with claim 7, wherein FOREIGN PATENTS the carrier means includes means for selectively positioning the finger `radially of said axis. 5791722 6/1933 Germany' 10. The mechanism in accordance with claim 7, where- 5 in the axis of the carrier means intersects the plane of RICHARD B' WILKINSON Prlmary .Exammer' the Wheel member in the space between the gear members. GERALD F. BAKER, Examiner.