US2431395A - Timer escapement - Google Patents

Description

Nov.25, 1947. v c. E. GODLEY I 2,431,355

DIMER ESCAPEMENT Filed Nov. 24, 1941 GSheets-Sheet 1 INVENTOR 674,225 I BY j X ATTORN Nov. 25, 1947. c. E. GODLEY 1 2,431,395

TIMER ESCAPEMENT Filed Nov. 24, 1941 6 Sheets-Sheet 2 U I mun INVENTOR (Jar/2: .ZT a/Zqy a flm ATTOR Nov. 25, 1947.

C. E. GODL'EY TIMER ESCAPEMENT Filed Nov. 24, 1941 6 Sheets-Sheet I5 INVENTOR jar/4s Z. J/qy.

ATTORN Nov. 25, 1947. c. E. GODLEY 2,431,395

TIMER ESCAPEMENT Filed Nov. 24, 1941 v e Sheets-Sheet 4 v ATTORNE NOV. 25, 1947. c, GODLEY 2,431,395

TIMER ESCAPEMENT Filed Nov. 24, 1941 6 Sheets-Sheet 5 INVENTOR E E '}drZa6 zrgddleg,

ATT NEY Nov. 25, 1947.

Filed Nov. 24', l94l EBB-55' TIMER GODLEY 2,431,395

ESCAPEMENT 6 Sheets-Sheet 6 INVENTOR ATTO Y5.

Patented Nov. 25, 1947 TIMER ESCAPEMEN T Charles E. Godley, Ferndale, Mich., assignor to King-Seeley Corporation, Ann Arbor, Mich., a

corporation of Michigan Application November 24, 1941, Serial No. 420,288

15 Claims. 1

The present invention relates to timing devices, and in particular is directed to the provision of an improved timer for producing an audible or other signal, or other operation, at the expiration of a selectively adjustable interval; and this application is a continuation in part of applicants copending application, Serial No. 379,925, filed February 21, 1941.

The principal objects of the present invention are to provide a timer of the above generally indicated character, embodying an improved clock movement which is economical of manufacture and assembly, and which is positive and reliable in operation; to provide such a timer embodying an improved positive escapement, employing a pallet adapted in one rotative position to lock the escapement wheel and adapted in another rotative position to permit the escapement wheel to advance; to provide such a structure, wherein the pallet is withdrawn from locking position by means of an extension spring, which is readily adjustable to alter the timing of the escapement and wherein the pallet is urged into locking position by the advance of the escapement wheel; and to generally improve the construction and arrangement of timing devices of the type to which the present invention relates.

With the above as well as other objects in View, which appear in the following description and in the appended claims, preferred but illustrative embodiments of the invention are shown in the accompanying drawings throughout the several views of which corresponding reference characters are used to designate corresponding parts and in which:

Figure 1 is a view in front elevation of a timer embodying the invention;

Fig. 2 is a view in axial vertical section through the timer of Fig. 1;

Fig. 3 is a detail view, taken along the line 33 of Fig. 2;

Fig. 4 is a fragmentary sectional View, taken along the line 44 of Fig. 2;

Fig. 5 is a detail view, taken along the line 55 of Fig. 2;

Fig. 6 is a detail view in section, taken along the line 6-6 of Fig. 5;

Fig. 7 is a view in section taken along the line 'l-'! of Fig. 5;

Fig. 8 is a View in section taken along the line 8--8 of Fig. 2;

Fig. 9 is a view corresponding generally to Fig. 8, but showing the hammer cocking mechanism in the off or released position;

Fig. 10 is a, view taken along the line Ill-l0 of Fig. 9;

Fig. 11 is a fragmentary detail view, taken along the line H--ll of Fig. 8;

Fig. 12 is a fragmentary detail view, taken along the line [2-42 of Fig. 9;

Fig. 13 is a fragmentary detail view, taken along the line i3i3 of Fig- 9;

Fig. 14 is a fragmentary detail view, taken along the line i il4 of Fig. 9;

Fig. 15 is a fragmentary detail view, taken along the line Iii-l5 of Fig. 10;

Fig. 16 is a diagrammatic View of the improved escapement, based upon Fig. 5, but drawn on an enlarged scale;

Fig. 17 is a View corresponding to Fig. 16, but showin the elements of escapement in difierent relative positions;

Fig. 18 is a view corresponding generally to Fig. 5, but showing the adaptability of the present escapement to wheels of different numbers of teeth;

Fig. 19 is a view in front elevation of a modified dial construction;

Fig. 20 is a View in elevation of a modified construction of an escape wheel;

Fig. 21 is a view taken at right angles to Fig. 20;

Fig 22 is a plan View of a fixture for assembling the hereinafter described clutch connection;

Fig. 23 is a, view in vertical central section, taken along the line 23-23 of Fig. 22;

Figs. 24, 25 and 26 are comparative views of a modified escapement construction;

Fig. 27 is a view similar to Fig. 24, showing a further modification of the escapement mechanism;

Fig. 28 is a side elevation of the balance staff and escapement element employed in Fig. 2'7; and

Fig. 29 is a view illustrating the manner in which the escapement element of Figs. 2'? and 23 is formed.

It Will be appreciated from a complete under standing of the present invention that the ire-- provements thereof may be embodied in timing mechanism of widely varying specific construetions, and intended for a relatively wide variety of difierent purposes. Also, in a generic sense, the character of the signal produced by the device may be of either audible, visual, or other character. In an illustrative but not in a limiting sense, the present improvements are herein dis-- closed in connection with a timing unitwhich operates to provide an audible signal.

Referring more particularly to Figs. 1 and 2 of the drawings, the present mechanism comprises generally a hammer mechanism designated as a whole as 35, which is directly connected to a main arbor 32, which, in turn, is adapted to be rotated in a starting direction from a normal or starting direction by means of a setting dial 34 and which is driven in the opposite or'timing direction by a movement designated as a whole as as. It will be appreciated that the movement 36, which has a clutch connection with the arbor so, is effective, upon release of the dial 34, to drive the hammer mechanism in the return direction at a substantially uniform rate, and that, consequently, the time interval for which the device is set is determined by the degree of angular movement through which the arbor 32 and the hammer mechanism 38 are moved in the setting direction by the dial 3%. As is described in more detail hereinafter, the setting movement of the dial also serves to wind or load the main spring 38, associated with the movement 36, and the initial setting movement also acts to cock the hammer mechanism 53. The hammer mechanism has associated therewith means to trip the same at the conclusion of the return movement, which tripping action enables the hammer mechanism to effect an operation. As previously mentioned, the hammer may, in a generic sense, be caused to effect a wide variety of operations and consequently, throughout the present description and in the claims, except where a specific type of operation is particularly referred to, the term hammer mechanism is used in a generic sense, as referring to a suitable operator or like part. In the present instance, the hammer mechanism is arranged to ring a bell, and as illustrated, the hammer mechanism is of the multiple type, and produces a succession of bell notes.

Considering the above-mentioned elements in more detail, and referring particularly to Figs. 2, 5 and 7, the movement 35 comprises a main gear 49, which drives the arbor 32 at a rate determined by the escapement. The escapement comprises the escapement wheel 52, a pallet Ml, a balance wheel 65, and an adjustable pallet spring 58.

More specifically, the main gear is rotatably journalled on a portion 58 formed on the arbor 32, and a face plate 52 secured to the back of the main gear 40 abuts a shoulder formed on the arbor, thereby preventing movement of the ear G8 to the right relative to the arbor 32. The other face of the main gear 55 is provided with a face plate 56, which is also seated on the portion 55 and directly and frictionally engaged by a clutch plate 53. The plate 58 is rigidly secured to and directly rotatable with the arbor 32.

A feature of the present invention resides in the method of and arrangement for securing the clutch plate 58 to the arbor 32 and for accurately predetermining the pressure which the plate 53 exerts against the main gear as, thereby, of course, determining the torque which the clutch can sustain without slippage. As clearly appears in Figs. 2 and 23, the inner marginal edge 55 of the clutch plate 53 seats against a relatively short fiat portion 62 on the arbor 32, and, preferably, the righthand face of the clutch plate 5 3, immediately adjacent the central opening therein, lies slightly spaced from a shoulder 55 on the arbor 32. In accordance with the present invention, the central opening in th clutch plate 58 is given a slightly rough or toothed marginal surface, and also, prior to assembly thereof with the arbor 32 and the gear 55, the central portion of the clutch plate 58 is pressed from the main body of the plate. In assembly, after the main gear 55 is applied to the arbor 82, the clutch plate 58 is simply pressed thereon, and, it being understood that the opening in the clutch plate 58 is of a diameter very slightly less than the diameter of the portion 52 of the arbor, the pressing on of the clutch plate 53 causes the central opening therein to solidly bind upon the portion 52 with a ratchet action, which positively prevents removal thereof. The pressing on movement of the plate 55 ultimately brings the main body portion thereof into frictional engagement with the face plate 55. The clutch plate 53 is preferably slightly cupped, with the concave face thereof presented to the face plate 55, and is also preferably provided with a series of equiangularly spaced, radially extending notches 59, four being preferable. Ihese notches extend inwardly from the periphery of the plate 58 and their length is preferably between 50% and of the radius of the plate 58. The plate 58 is preferably formed of springlilre material, and consequently, in the assembled position Of the parts, a substantial proportion of the originally concave facial area of the plate 58 resiliently engages the face plate 55 with a frictional holding effect which progressively increases as the pressing on movement of the clutch plate 58 is continued.

It will be understood, as hereinafter described, that even in the normal or zero setting of the timer, the main spring 38 is.loaded to a substantial extent, and this loading is, of course, increased each time the dial is rotated to set the timer for a predetermined timing interval. The holding effect of the clutch connection between the members 58 and 58 must, of course, be sufficient to reliably sustain the maximum loading of the spring 38 without introducing slippage. On the other hand, in order to facilitate a winding operation, and also to minimize the duty of the clutch elements, it is desirable to maintain the slippage value of the clutch at as low a value as is consistent with the just-mentioned duty. These considerations make it desirable to accurately gauge the frictional holding effect of the clutch elements, and in accordance with the present invention, this may be accomplished as an incident to the above-mentioned pressing on operation.

Referring particularly to Figs, 22 and 23, an illustrative fixture comprises a die 5|, having a pocket 53 therein, in which the clutch plate 58 may be seated, the form of the pocket being such that only the radially central parts of the plate 53 are engaged thereby. With plate 58 thus preliminarily positioned within the pocket 53, the arbor 32, with the plates 52 and 56 and the gear 40, previously assembled thereon, may be projected downwardly through the opening in the die 5| towards the position of the parts shown in Fig. 23. The latter projecting movement brings the gear 40 into relatively non-rotative engagement with a spring loaded indicating member 55. Preferably and as illustrated, this relatively non-rotative connection is afforded by forming the inner peripheral face of the member 55 as an internal gear with which the gear 40 may mesh. The assembly 55 is provided at one side with a pointer 51, which is adapted to register with a relatively fixed scale 6|, and is also provided with a diametrically opposite extension 63 to which one end of the loading spring 55 is secured. The other end of the spring 65.is anchored. It will be understood that any suitable means (not shown) may be employed to rotatively support the assembly 55 above the die 5|, the principal requirement being that the toothed portion of the assembly 55 shall be of sufficient depth so that the gear 40 remains meshed there with throughout the full range of the pressing on movement of the clutch plate 58.

With the parts thus preliminarily positioned, a compressive force may be applied between the upper end of the arbor 32 (Fig. 23) and the die 5|, which forces portion 62 on the arbor 32 through the roughened central opening in the plate 58. Concurrently with the application of this pressing force, a rotative force may be applied to the arbor 32, so as to cause the same to rotate in a clockwise direction, as viewed in Fig. 22. The initial pressing on movement of the plate 58 affords a non-rotative connection between the plate 58 and the arbor 32. Consequently, this rotation of the arbor 32 drives the clutch plate 58. As soon as the pressing on movement is continued far enough to bring the clutch plate 58 into engagement with the face plate 56, a rotative force is applied through the clutch to the gear 39. .This force tends to rotate the assembly 55 in a clockwise direction, as viewed in Fig. 22, which latter rotation stresses the spring 65. It will be evident that the degree to which the spring 65 is stressed, and, consequently, the scale reading to which the pointer 5'! is moved, depends upon the frictional holding efiect between the plates 56 and 58, and that this holding effect is progressively increased as the pressing on movement is continued. The assembly.operation is, of course, completed when the pressing on movement brings the pointer 51 to the desired scale reading.

The main gear 4i drives the escapement through a train of intermediate gears comprising the pinions iii and 72 and the gears 14 and 15 which are carried by a stafl 18, and further comprising the pinions 89 and 82 and the gear M, which are carried by the staff 86. The staff 85 also carries the escape wheel 42. The staffs l3 and 86, and the staff" 98 which carries the balance wheel 46 and the pallet 4d, are supported by front and rear movement plates 92 and EM, which, in turn, are rigidly maintained in predetermined spaced relation to each other by the hereinafter described pillars 96. As illustrated, the staffs l3 and 86 are each provided with reduced end portions, which are freely rotatable within corresponding bearing openings provided therefor in the movement plates 92 and M, it being understood that the staffs are permitted to have a very slight amount of longitudinal play so as to insure a free running condition thereof. The opposite ends of the staff 9d are pointed, one such pointed end being received in a corresponding tapered seat formed in a plug 98 which is conventionally pressed through the movement plate 92. lhe other tapered end of the staff 93 is received in a corresponding tapered seat formed in a plug see, which, in the preferred practice of the invention, is relatively freely slidable within the opening 532 provided therefor in the movement plate ed. A leaf spring HM, one end whereof is riveted to the movement-plate 94 as by a rivet E05, has its other end [93 bearing directly upon the back of the plug Mid, and acts to continuously urge the same towards the plug 98, thereby maintaining a predetermined loading between the staff so and its bearing. A limit to such inward movement is afforded by the shoulder Ht on the plug Hit, and a limit to outward movement of the plug we is afforded by a member H2, carried by the hereinafter described hammer mechanism. It will be understood that the staffs 78 and 85 may be provided with bearings which correspond to those described for the staff 90, it being appreciated, however, that the latter type bearings are of principal importance in connection with the staff 953, since this staff is driven in one direction by the escapement spring 48, and consequently is considerably more sensitive to changes in bearing pressures than are the other staffs which are driven entirely by the relatively heavy main spring 38. It is found in practice that certain of the assembly operations, which occur after the main and intermediate gears and the escapement elements are assembled between the movement plates 9E3 and 92, tend to distort the plates, and any binding and locking of the staff 90 which might otherwise be caused by such deformation is entirely overcome by the just-described free running bearings for the staff mentioned.

It will be appreciated that in usual constructions, a substantial part of the ticking noise produced by the operation of the escapement is due to the play which normally must be allowed between the balance staff and its bearings, which play enables the balance staff to oscillate in an axial direction. Constructions heretofore used have employed, of course, an adjustable bearing arrangement. The setting of the adjustable bearing is, however, a rather critical operation and one that complicates the assembly operation. Moreover, at least some play must be left in the bearing, as will be understood, to accommodate changes in temperature and the like. The present arrangement not only eliminates these assembly difficulties, but also entirely eliminates the necessity for any play in the balance staff bearings, since the spring ltd serves to continuously hold both ends of the staff seated in the corresponding bearings. The elimination of this play in the bearings materially reduces the intensity of the ticking noise, particularly when the present bearing arrangement is employed in connection with a flexible escape wheel of the type shown in Figs. 20 and 21 and described hereinafter.

The movement plates t2 and 525 are also provided with aligned bearing openings in which the arbor 32 is journalled, it being noted that axial play of the arbor 32 is limited by the engagement of the shoulder 9i thereon with the movement plate 9 1 and by the engagement of the shoulder 93 thereon with the movement plate 92.

The pinion it, which directly meshes with the main gear til, and the companion gear M are rigid with respect to each other and are ress fitted upon the corresponding shaft it. The immediately adjacent pinion l2 and its gear iii in turn are rigid with each other and are freely journalled on the staff 78 between the just mentioned gear i l and a sleeve 1 M, which, in turn, is press fitted upon the staff 18. Similarly, the pinion 80 and the gear 84 are rigid with respect to each other and are press fitted upon the staff 36. The pinion 82 and the escapement wheel :52, in turn, are rigid with each other, and are freely journalled on the staff 86 between the gear 84 and a sleeve i i t, which is press fitted on the staif 86.

It will be noted that each of the staffs l8 and 85 carry two gear and pinion assemblies, which pyramiding 0r doubling up of the gear and pinion assemblies is advantageous for several reasons. First, this pyramiding obviously reduces the required number of staffs, and thus not only simplifies the unit as a whole but reduces the space requirements thereof. Further, and of perhaps even greater importance, this pyramiding enables the load reactions on the staffs to be balanced out in such a way as to avoid any heretofore encountered binding of the staifs as the gears and pinions wear in.

Considering now the escapement mechanism, and referring particularly to Figs. 5, 6, 7, 16 and 17, the previously mentioned balance wheel 46, the pallet 44, and a spring hook E29 are press fitted upon the staff and so rotate as a unit 7 therewith. The pallet 44 is formed to define a tooth 522 and a locking shoulder I24. The looking shoulder I2 3 co-operates with each tooth of the escape wheel to momentarily stop rotation of the latter when the parts occupy the relative positions shown in Fig. 16, and the tooth I22 of the pallet is engaged by each successive tooth of the escape wheel 42, upon release of such tooth from the shoulder ii-lfi, so as to rotate the pallet 44 from the position shown in Fig. 17 back to the blocking position shown in Fig. 16. The pallet 44 is rotated from the blocking position of Fig. 16 in a clockwise direction surhciently far to release the escape wheel tooth from the shoulder I24, by

means of the extension spring 58, one end where- 1 of is hooked to the spring hook I20, and the other end whereof is secured to a bracket I26. The other end 01' the bracket i126 rides in a guide slot l28 formed in the bracket support I39, which support is rigichy secured to the adjacent movement plate 92. The bracket I26 also receives a threaded adjusting screw I32, which may be rotated in one direction to extend the spring 48. Rotation of the screw in the opposite direction enables compression spring iSi to force the bracket i213 to the right, thereby shortening the spring 63. The use of an extension type spring for co-operating with the pallet 34 is regarded as a feature oi the present construction, since such extension spring can very readily be adjusted after all or" the parts are assembled, so as to vary the tension of the spring 48 throughout a very considerable range.

The parts are shown in Figure in the position to which the pallet 45 is moved by the passage therepast of a tooth of the escape wheel 32. When the pallet t4 occupies the just mentioned position, the pilot spring 18 occupies an over center position in which it urges the pallet 34 a clockwise direction, as viewed in Figures 5, l6 and 17. As long, however, as the pallet occupies the just mentioned position, it blocks the tooth b of the escape wheel 42 and holds the latter against rotation. The spring do is efiective to move the pallet 43 from the just mentioned position toward the position shown in Fig. 1'7, during the course of which movement the shoulder E thereof passes out or blocking relation to the tooth b of the escape wheel 42, enabling the latter to start in a clockwise direction under the influence of the main spring 38, which, as described below, acts directly against the arbor 32, which arbor is clutched to the escape wheel 42 through the previously mentioned main gear so and the intermediate gears. As soon as the escape wheel is free of the shoulder I24, the tooth 1) thereof moves toward the tooth I22 oi the pallet to, which latter tooth is now in the path of movement of the tooth b. Consequently, the tooth b or". the escape wheel strikes the tooth of the pallet l and rocks the latter from the pc .511 or l? to the position of Fig. 16, during which movement the pallet spring ts is again loaded. This movement of pallet dd brings the shoulder iZt into blocking relation to the next successive tooth of the escape wheel 42, enabling the pallet to momentarily stop the movement of the escape wheel. As soon, however, as the pallet spring 43 is enabled to overcome the rotative force imparted to the pallet i l by the escape wheel this spring again rocks the pallet out of the blocking position of Fig. 16 towards the free position of Fig. 17.

An important feature of the pallet 44, as illustrated in Figs. 16 and 1'7, is the rounded corner I25 between the braking shoulder I24 and the notch 52? in advance of the tooth PM. It will be noted from Fig. 16 that the point on shoulder i2 1 engaged by the spoke of the escape wheel 42 is in an area which is cylindrical in form, but that a limited clockwise movement of the pallet it under the influence of spring 48 shifts the point oi engagement to the rounded corner I25.

As the point of engagement moves over the rounded corner I25, the distance of the point of engagement from the center of stafi 98 progressively decreases. This progressive decrease of the radius of the point of engagement has two important functions: first, it reduces the effect of the frictional resistance to clockwise rotation of pallet st to compensate for the progressive reduction in the force exerted by spring 48 and, second, it permits the escape wheel to begin its movement and accelerate before it is actually released by pallet A l, thus increasing the speed with which it strikes tooth I22.

It will be appreciated that the spring 48, balance wheel 66, pallet hook iii and stafi constitute an escapement system, which oscillates between the blocking and free positions shown in Figures l6 and 17, respectively. It will further be appreciated that the escape wheel 42 is enabled to advance one tooth during the course of one full cycle of movement of the just mentioned escapement system. The amplitude of the movement may be expected to vary somewhat in accordance with the loading of the main spring and in accordance with the angular spacing between successive teeth of the escape wheel The period or rate of the movement, however, is determined substantially entirely by the weight of the moving parts and by the tension of the spring 43, so that for any given tension of the spring 43, such rate or period is substantially independent of the loading of the main spring and also is substantially independent of the angular spacing between the teeth of the escape wheel 42.

As afore-mentioned, the period or rate of the escapement can be varied over a substantial rang by varying the tension of the spring 48, variations up to 30% having been found readily available in practice. It is preferred in practice, therefore, to employ the adjustment of the tension of the spring 48 as the means for calibrating the timer, an increase in tension serving to increase the escapement rate and a decrease in tension serving to decrease the escapement rate. This adjustment can, of course, be made by the simple expedient of turning the mounting screw I32 in one direction or the other.

As was previously mentioned, the escape rate appears to be substantially independent of the angular spacing between the successive teeth of the escape wheel 42. Consequently, by altering the number of teeth on the escape wheel, an

exceedingly wide variation in the escape rate is readily available. More specifically, the escape wheel shown in Fig. 5 is provided with eight teeth, whereas the wheel of Fig. 18 is provided with four teeth. Accordingly, the wheel of Fig. 5 requires twice as long to make a complete revolution as does the wheel of Fig. 18, and the structure of Fig. 5 has one-half the escape rate of the structure of Fig. 18. It will be understood, of course, that by employing twice the number of teeth as are employed in the wheel of Fig. 5, the escapement rate is reduced by one-half, and that other proportionate increases and decreases of the escape rate provided by the structure of Fig. are obtainable by corresponding other proportionate decreases and increases in the number of teeth on the escapement wheel.

The actual escape rates employed and the gear ratio between the escape wheel and the arbor 32 determine, of course, the time interval afforded for each full 360 of movement of the arbor 32 and the dial l, or for each fraction of such full movement. Various escape rates and gear ratios may be employed, as will be understood. By way of illustration but not of limitation, it is preferred to adjust the escapement so as to provide an escape rate of 216 escape teeth per minute, which corresponds, of course, with an eighttoothed wheel, to 2'7 escape wheel revolutions per minute and, with a four-toothed wheel, to 54 escape wheel revolutions per minute. It is further preferred to adjust the gear ratio between the escape wheel so that the eight-toothed wheel provides a sixty minute period for a full revolution of the dial. With this gear ratio, a four-toothed wheel, of course, provides a 30 minute timing interval and a sixteen-toothed wheel provides a two hour timing interval.

As previously mentioned, the movement plates 92 and 9d are maintained in fixed, spaced relation to each other by means of pillars 96, three of which are shown in the drawings and which are equiangularly spaced. A feature of the present construction resides in forming a positive but readily releasable connection between the pillars 93 and the plates 82 and 53 5-. Referring particularly to Fig. 15, each movement plate is provided with a keyhole slot $9 individual to each pillar, and each pillar 96 is notched, as indicated at 8'5, to define fiat-sided sections 85 which are narrow enough to pass through the neck of the corresponding keyhole slot. It will be understood that a pillar is assembled with respect to its plates and 94 by rotating the pillar so as to bring the narrow portions 95 thereof into alignment with the necks of the keyhole slots, and that after the pillar is moved into the bases of the keyhole slots. the same is rotated through a slight angle so as to bring the narrow portions 95 out of alignment with the necks of the slots. The fit between the slotted pillars and the slots in the movement plates is preferably such as to frictionally prevent unintentional rotation of the pillars. It will further be appreciated that the notches er in the pillars 95 are spaced along the bodies thereof in accordance with the desired spacing between the movement plates 92 and lit, and that the length of each such notch is substantially equal to the thickness of the associated movement plate.

Referring particularly again to Figs. 2 and l, the main spring 38 is of usual spiral form, one outwardly turned end E li! whereof is hooked through an opening provided therefor in the main spring housing Hi2, and the other inwardly turned end ltd whereof is hooked through a corresponding opening provided in the outer wall of a spring dog i i-i5. It is preferred to anneal or otherwise treat the main spring prior to assembly so as to overcome any otherwise existing tendency of this spring to take a set after being placed in service.

The dog M6 is of cup-shaped form, the inner whereof open, and the base its whereof is provided with a non-circular opening, which nonrotatably receives the complementarily formed portions t lt of the arbor 32. The inner surface of the base its bears against shoulders, such as I50, formed on the arbor 32, and the dog t lt is maintained in place on the portions M9 by a nut l52, which is threaded on to the outer reduced end of the arbor 32. The main spring housing 152, in turn, is provided with a plurality of axially extending, circumferentially distributed teeth or projections which project through corresponding openings provided in the front movement plate 92. The housing Hi2 may, therefore, be secured to the movement plate $2 in any one of a plurality of rotative positions, each whereof corresponds to a different initial loading of the main spring 38.

The just described arrangement, wherein the main spring and its housing are mounted external to the movement plate and are readily connectible to and disconnectible therefrom, not only permits ready replacement of the main spring, but also serves a further important advantage of enabling the movement, comprising the arbor, the main gear, and the intermediate gears, to be freely run in before the escapement and the main spring are applied.

The setting dial 34 is herein illustrated as being formed of a plastic or other moldable composition, having a generally circular body portion provided with graduations Ifill, and having a blade-like or otherwise formed readily graspable central handle portion 162. The inner face of the dial 3 3 is provided with diametrically opposite pockets its, which receive tongs IE6 provided on a setting lever I63. The lever 163, in turn, is nonrotatably secured to the arbor 32, between the nut I52 and the dog H56. The dial 34 is also provided with a central recess I70, which receives the nut I52, and preferably, and as illustrated, a usual holding spring H2 surrounds the nut and frictionally engages the inner surface of the pocket fill. If desired, a set screw IN or other means may be provided to more positively secure the dial 3 3 in assembled relation to the arbor 32.

The provision of a circular dial having the graduations distributed therearound is regarded as an important feature of the present construction. It will be appreciated from Fig. 1 that in the zero or re-set position of the timer, the zero point on the dial 34 registers with the reference mark Hit or other indication carried by the face plate V58. To set the timer, the dial 3 1! is rotated clockwise, as viewed in Fig. 1, from the just mentioned initial position, during which movement the graduations on the dial successively register with the reference mark I 75 on the face plate. The interval for which the timer is set may thus be initially read at a fixed point on the unit, thus entirely overcoming the confusion which results from the use of dials wherein a movable pointer on the setting member is required to be moved into registry with fixed numerals distributed around the face plate.

From the description thus far given, it will be appreciated that the just mentioned clockwise setting movement of the dial 34 positively rotates the arbor 32 in a counterclockwise direction as viewed in Fig. 5, said rotation being transmitted to the arbor through the driving connection afforded by the setting lever I68. The just mentioned rotation of the arbor correspondingly drives the spring dog I46 in a counterclockwise direction, as viewed in Fig. 4, thereby winding up or loading this spring. The rotation of the arbor 32 applies a rotative force through the clutch plate 53, which tends to rotate the main gear as in a counterclockwise direction, as viewed in Fig. 5. This tendency is transmitted through the gear train to the escape wheel 42 and tends to rotate the latter in a counterclockwise direction, which is the opposite to the direction of rotation normally imparted thereto by the main spring 38. The just mentioned reverse movement of the escape wheel 42 brings a tooth into engagement with the back of the tooth I22 on the pallet 44. The radius of the pallet in the region 'at the back of the tooth I22 is too great to allow a movement therepast, in a counterclockwise direction, of the escape wheel. The pallet 44 therefore operates to prevent reverse movement of the escape wheel and of the main gear 40. During a setting movement of the dial 34, therefore, the clutch plate 53 slips past the main gear 40. Upon release of the dial 34, however, the main spring 38 becomes eirective to apply a torque to the arbor which rotates the latter in a clockwise direction, as viewed in Fig. 5, the rate of such clockwise or return movement being determined, of course, by the escapement, as aforedescribed. The return movement is stopped at the zero position of the timer by the bell hammer mechanism now to be described, and at the conclusion of such movement also, the bell hammer mechanism operates to give one or more audible signals.

Referring particularly to Figs. 2 and 8 through 14, the hammer mechanism comprises generally a driving dog I80, 2. setting pawl coil I82, a plurality of hammers I84 and I85, two being shown by way of illustration, and a tripping lever I87, The dog I80 is illustrated as a cup-shaped stamping having a non-circular opening in its base which co-operates with flats such as I8I on the arbor 32 to provide a driving connection for the dog I80. The inner face of the dog I80 engages the trip lever I81. and movement of the dog I80 along the arbor 32 in the other direction is limited by the overlying portion I89 of the hereinafter mentioned bracket 204. The pawl I82 is of generally bell crank shape having legs I86 and I88. A pair of ears I90 extend laterally from the leg I88, and are provided with bearing openings through which the reduced end portion I92 of the arbor 82 is freely passed. The pawl I82 is normally maintained in seating relation to the dog I80 by means of a compression spring I96 which surrounds the reduced portion I92 of the arbor, and which spring normally causes the dog I80 to engage the lever I81. One end of spring I96 bears against the leg E88 and the other end thereof bears against the leg I85 of the pawl. The latter end of the spring is straightened, and is received in a notch I98 cut in the reduced portion I92 of the arbor. With this relation, it will be appreciated that any movement of the pawl I82 to the right, as viewed in Fig. 2, compresses the spring I86 somewhat, rendering it efiective, upon release of the pawl, to restore the latter to the normal position shown in Fig, 2.

A driving lug 209, having a sloping back, is pressed outwardly from the driving dog I88, and upon rotation of the dog I89 in a counterclockwise direction, from the off position shown in Fig. 9, toward the on position shown in Fig. 8, the abrupt face of the lug 200 engages behind the leg I88 of the pawl I82, and applies a rotative force to the latter. The just mentioned rotation of the pawl I82 brings the hammers I 84 and I85 from the tripped positions of Fig. 9 to the cooked positions of Fig. 8, as hereinafter described. Shortly after the pawl reaches a position in which the hammers assume the cooked positions, the leg I85 of the pawl encounters a gradually rising cam surface 202 which is struck from the body of a bracket 204 which is rigidly but adjustably secured to the rear movement plate 84. The continued movement of the pawl past the cam surface 202 enables the latter to cam the pawl I82 from the position shown in Fig. 2 to a position far enough to the right thereof to clear the lug 208. When the lug 280 clears the pawl I82, the driving force of the dog I on the latter is relieved, enabling a continued setting movement of the dial and of the arbor 32 without further altering the position of the pawl E82. On the other hand, during the return or timing movement of the arbor 32, the dog I 80 moves in a clockwise direction, as viewed in Figs. 8 and 9. Due to the fact that the pawl I82 frictionally engages the surface of the dog I80, and also has a frictional engagement with arbor 32, the return movement of the arbor 32 may serve to return the pawl I82 from the setting position shown in Fig. 8 to the setting position shown in Fig. 9. If not, the gradual return movement of the dog 58:? ultimately brings the grounded back of the lug 288 into engagement with the front face of the pawl leg I86, enabling the dog H353 to rotate the pawl I82 to the normal position of Fig. 9. A limit to the return movement of the pawl I82 is afforded by a lug 206 which is struck outwardly from the previously mentioned bracket 284. As soon as the pawl I82 engages the lug 286, the further movement there of is interrupted, and the continued movement of the dog I89 enables the sloping back of the lug 280 to again lift the pawl I82 off its seat, enabling the lug 298 to passbehind the pawl to the normal position shown in Fig. 9.

Except as hereinafter noted, the hammer I84 I85 are duplicates. The hammer I84 comresses a relatively heavy head 2I0, which is soured at the outer end of a length of relatively heavy spring wire 292, the other end whereof is igidly secured to a post 2I3 which is secured to and projects from the previously mentioned bracket 294. In the released position of the hammer shown in Fig. 9, the wire 2I2 bears, at an intermediate point, against one of the previously mentioned pillars 96, which acts to limit the radial outward movement of the hammer head H9. The head 250 is made up of two complementary portions Mile and 2I8b which are permanently secured to each other, as by riveting over the ends of the tongues ZIEic, formed on the member 240a, and which project through corresponding openings provided therefor in the body of the member 2501). The free end of the wire 2 I2 is rigidly clamped between the portions 2I8a and The head member 2I9b is provided with an extended arm 2M, having a finger 2H5 which lies in the path of movement of leg I88 of the pawl and also having a hook 2I8. In the cooked position of the hammer, the hook engages the latch 228 which may be and preferably is formed as a flange projecting from the bracket 204. As most clearly appears in Fig. 10, the flange 228 is provided with a slot 222 individual to each hammer. In the cocked position of each hammer, the hook 2E8 thereof engages over the lower end of each slot 222.

It will be appreciated that the tripping of the hammers I84 and 85 from the cocked positions of Fig. 8 enables these hammers to give the signals for which the device is designed and this tripping action is accomplished by means of the previously mentioned tripping lever I8'I, which is loosely journalled on the arbor 32 for swinging movement from the oiT position shown in Fig. 9 to the on position shown in Fig. 8.

Fhe previously mentioned driving dog [fill is provided with an inwardly struck lug Zilil, and the just mentioned tripping lever it? is provided with an outwardly struck lug 2'52 which lies in the path of movement of the lug The normal position of the parts is that shown in Fig. 12, in which the lug 23E lies immediately in front of, but in engagement with, the lug 232 and in. hich position the nose 23 of the tripping lever it! engages an abutment 236 formed on the previously mentioned bracket flange 22%. The tripping lever liil thus co-operates with the do ii??? to form a limit stop to the return or timing movement of the timing device, and it will be understood that the dog let drives the lever iiil into engagement with the abutment 236 when the zero point on the dial registers with previously ientioned mark H on the face plate llti (Fig. l) A setting movement of the timer, as previously described, causes the arbor to drive the dog Hill in a counterclockwise direction, as viewed in Figs. 8 and 9. This movement causes the lug 23% to move away from the lug 232. The friction between the interengaging marginal. edge portions of the dog and the lever till enables the dog i331 to frictionally move the lever it? from the off position of Fig. 9 to the on position of Fig. 8. In the latter position, the nose 233 thereof engages an abutment 2% formed on the previously mentioned bracket After, as the just mentioned limit to the movement of the tripping lever i3? is reached, slippage occurs between the lever i8! and the dog tell, enabling latter to continue in the counterclockwise direction without further altering the position of the lever If the setting movement of the dial is continued throughout the full 360 degrees of movement thereof, the concluding part of such movement brings the lug 23o int-o engagement with the back of the lug 2321. Consequently, the tripping lever l8! co-operates with the dog ib not only for the purpose of forming a limit stop to the return movement of the timer, but also for the purpose of forming a limit stop to the setting movement thereof.

Assuming that the setting movement of the dog l as influenced by the dial lid, is interrupted either when the just mentioned limit is reached or is interrupted at an intermediate position, the release of the dial Sill enables the main spring so to initiate a return or timing movement of the dog 586. During the course of the just mentioned return movement, the lug 23!! again engages the face of the lug and continued return movement of the dog its cams the trip lever i3 from the on position of Fig. 8 towards the on position of Fig. 9. During this movement of the lever E57, the flange 242 formed thereon engages under the noses 244 of the hammer arms 2M. This action enables the tripping lever lii'i to cam the noses 2M radially outwardly, as viewed in Fig. 8, and ultimately releases these arms from the latch 22s. Upon being released, the energ stored in the springs are associated with the individual hammers whips the heads of the hammers radially outwardly. as viewed inFigs. 8 and 9. During the course of this whipping movement, the springs engage the supporting post 96, as described previously, so that the final whipping movement occurs as a result of fiuxure of that part of each spring between the pillar 9t and the associated head. The weight of the heads 2lii carries them 14 to the position shown in Fig. 9, enabling them to strike the bell 2% associated with the timer.

It is sometimes desired to produce two bell notes or two successive operations of the hammers H4 at spaced intervals. This result may be accomplished, as shown in Fig. 10, by making the edge 2% of flange 242 of stepped form, or alternatively, if the edge 243 is a straight edge, by providing slightl diiierent tapers on the undersides of the noses 24 3 of the hammer arms, which portions are engaged by the flange 2% of the tripping lever.

It will be noted from Figs. 2 and 10, that the movement 36 and the principal parts of the hammer mechanism are housed within a cup-shaped enclosure 258. The base of the enclosure 25%] is provided with three openings, through which the extreme ends of the pillars 96 are passed, and in order to secure the enclosure 259 against axial movement off of the pins, a conventional clip spring 252 is preferably employed, the body whereof hooks beneath grooves formed in the pin extremities, as will be understood. The side of the enclosure 254] is provided with an opening 254, through which the heads of the hammers I34 and it? may project upon being tripped by the tripping level Ial, and in the present instance, the bell 2%, which is also of generally cup shape. is secured directly to the back of the enclosure 2% by means of a countersunk screw 25%.

A feature of the present arrangement resides in an improved method for mounting and adjusting the hammers, it being appreciated that in order to ensure a clear, unblurred note from each hammer, the normal spacing between each hammerhead and the inner surface of the bell should be held between rather close limits. In view of the fact that each hammer is carried by a section of spring wire, and further in View of the fact that the characteristics of this wire vary somewhat, the present invention provides for the use of a fixture having pillars corresponding to the pillars and 95, against which each spring 2l2 bears, viewed in Figs. 8 and 9, together with means for supporting the head elements Zita and Zillb in proper position. Thus, the free end of the spring 2 l 2 may be allowed to take up a free radial position between the head elements 2 i (la and 2 l 0b, after which the elements 2963a and illilb may be rigidly secured together with the spring 2l2 clamped therebetween.

It will be recalled from the previous description hat the abutment 2% on the hammer bracket co operates with the trippin lever It! to form a limit to the setting movement of the timer, and that the abutment 2% carried by the bracket 2% co-operates with the lever i8l to form a limit to the return or timing movement of the timer. Accordingly, in order to allow for initial adjustment of the timer, so as to insur that the zero point on the dial 341 will arcuately register with the mark Ht on the face plate H8 in the reset position. of the timer, the bracket 2% is rotatably adjustable relative to the movement plate 92. For this purpose, the bracket 2M- is secured to the movement plate 92 by means of three circumferentially distributed screws 269, each whereof may be threaded into a tapped opening in the movement plate 9 5, and each whereof passes through elongated slot formed in the bracket 2%. As illustrated, fine adjustments of the bracket 264 facilitated by providing the latter with a series of gear-like teeth 262, which are disposed for meshing engagement with corresponding teeth on a tool (not shown) which may be introduced into a drilled opening 2% in the mounting plate 92 and 15' rotated so as to correspondingly rotate the bracket 284.

It will be noted from the previous description that the entire time assembly is directly supported by the movement plates 92 and 94-. In order to secure the timer to the face plate I18, it is preferred to provide the latter with a plurality of inwardly struck lugs 25L which pass through corresponding slots formed in the movement plate 82 and which lugs may be slightly twisted by a pair of pliers or similar tool so as to lock the parts in assembled relation to each other. The twisting of the lugs draws the inner marginal edge of the enclosure 250 into engagement with the inner face of the face plate I78. The face plate I18 may, of course, be secured to any suitable casing or box in any desired manner. The just mentioned twistable lugs are found in practice to admit of frequent removals of the movement from the face plate without impairing the efficiency of the connection, or without causing the lugs to break off.

The present escape mechanism is found in practice to operate relatively quietly. In certain instances, however, it is found preferable to utilize the somewhat resilient escape wheel construction, shown in Figs. 20 and 21. In these figures the escape wheel 219 is formed of a single sheet of metal, such, for example, as spring bronze. The center body portion is planar and is provided with an opening 2'E2 to receive the supporting arbor or stafi. The successive teeth of the escape wheel 278 are constituted by fiat ends 214 and spokes 2'53. It will be noticed that the ends 214 are substantially co-planar with the center body portion of the wheel, but that the spokes 216 are twisted relative to the ends and the body through approximately 90 degrees, so that such spokes relatively readily flex slightly when they engage the associated pallet, such as 44. This flexing softens each impact between the escape wheel and the pallet and consequently makes the operation of the escapement wheel exceedingly quiet.

Considering now the operation of the timer as a Whole, it will be appreciated that th parts are shown in Figures 1 and 9 in the normal, or off, position thereof, in which the zero point on the dial 34 registers with the mark I16 on the face plate I18 and in which the hammers I84 and I85 occupy their released positions. In these latter positions the springs associated therewith bear against the associated movement pillar 9B, and are thereby maintained out of contact with the bell 2&6. Under thes conditions, also, the main spring is subjected to a normal loading determined, as previously described, by rotating the spring housing I l2 relative to the arbor as an incident to the assembling of the main spring with the movement The main spring thus urges the arbor 32 in a clockwise direction, as viewed in Figure 9, tending to move th dial in a counterclockwise direction (Figure l) past the zero point. Such movement is, however, prevented by the engagement of the nose 23 of the tripping lever I8? with the abutment 236 on the adjusting bracket 28%. Until set by the dial 34, therefore, the timer remains at rest at the just mentioned zero position.

Assuming it is desired to effect an operation of the timer, the dial 34 may be rotated in a clockwise direction, as viewed in Figure 1, throughout all or part of the permitted 360 of movement thereof. The arbor 82 moves directly with the dial during this setting movement. The initial arbor movement drives the movement 36 in an opposite direction until such a time as a tooth of the escape Wheel 42 binds against the back of the pallet tooth I22, thereby blocking further such reverse movement. Following this blocking action, the continued movement of th arbor 32 causes slippage of the clutch plate 58 past the main timer gear 48. The setting rotation of the arbor 32 also winds up the main spring 38, as previously described.

The setting rotation of the arbor 32 causes a corresponding rotation of the dog I89 associated with the hammer mechanism. The initial such rotation of the dog I80 rocks the pawl I82 in a counterclockwise direction, as viewed in Figure 9, enabling the leg I88 thereof, through its engagement with the fingers 2I6 of the hammer arms 2I4, to move the hammers from the off, or tripped, position of Figure 9 to the cocked positions of Figure 8, at the conclusion of which movements the hammer arms snap behind latching bracket 220. Shortly after the just mentioned latching of the hammers is effected, the arm I88 of the pawl I82 rides up on the lug 202 and is thereby cammed to the right, as viewed in Figure 2, far enough to clear the driving lug 208 on the dog I80. It will be appreciated that th setting movement may be stopped at any time after the cooking of the hammers is effected, which cocking may be arranged to take place in the course of a relatively few degrees of rotation of the dial 34.

Due to the frictional connection between the dog I88 and the tripping lever I87, the initial rotation of the dog I88 moves the tripping lever from the on position of Figure 9 to the on position of Figure 8, in readiness to provide a limit stop to the setting movement of the dial 34. This movement of the tripping lever I8! also carries the flange 242 thereof out of co-operative relation to the noses 228 of the hammer arms so that the tripping lever I81 does not interfere with the cocking of these hammers.

If the setting movement is continued throughout the full 360 of permitted movement thereof, the final such movement thereof brings the lug 238 on the dog I into engagement with the back of the lug 232 on the tripping lever I81, thereby tending to rotate the latter in a counterclockwise direction beyond the position shown in Figure 8. Any such further movement is, however, prevented by the engagement of the nose 238 of the tripping lever with the abutment 240 on the adjustable bracket 284. The lever I81, therefore, prevents movement of the dial 34 beyond the full 360 of movement.

Assuming the dial 34 is released at any point between the point at which the hammers are cooked and the just mentioned limit position, the main spring 38 is immediately rendered effective to drive the arbor 32 in a clockwise direction (Figures 5, 8 and 9) at a rate determined by the escapement which controls the return movement of the arbor 32 through the clutch connection between the clutch plate 58 and the main gear 48. During the course of such return movement of the arbor 32, the dog I88 may be expected to frictionally drive the pawl I82 back to the position of Figure 9. If the frictional force is not sufficient to do this, the continued movement of the dog I88 brings the lug 288 into engagement with the back of the pawl arm I86, enabling the latter to positively return the pawl. When the pawl reaches the normal position shown in Figure 9, the arm I88 thereof engages the fixed lug 286, enabling the lug 200 to cam the pawl I82 to the right, as viewed in Figure 2, far enough to permit the lug 200 to pass behind the pawl and resume the position shown in Figure 9. As the dog I80 approaches the zero, or starting, position, the lug 230 on the dog I80 comes into engagement with the lug 232 on the tripping lever I81. Continued return movement of the dog I80 swings the tripping lever I87 from the on posi tion of Figure 8 toward the off position of Figure 9. In the course of this movement, the flange 242 on the tripping lever I81 successively engages the noses 220 on the hammer arms 2I4 and cams these arms out of engaging relation to the latch 220. As each hammer arm is released from the latch, the energy stored in the spring 2I2 associated therewith whips the head of the hammer into engagement with the bell 246, as described above. It will be understood that the interval between each bell note is determined by the configuration or proportioning of the noses 244 of the arms 2I4, it being preferred, of course, that the final bell note be timed to occur substantially simultaneously with the arrival of the dial at the zero position. When the dial arrives at the zero position, also, the nose 234 of the tripping lever l81 engages the abutment 236 on the bracket 204, thereby stopping the return, or timing, movement.

As described above, the escape rate of the present mechanism can be varied over a substantial range by adjusting the tension of the spring 48 and by changing the number of teeth on the escape wheel 42. For each escape rate, also, the time required for a full 360 of travel of the dial depends upon the gear ratio employed. Certain changes in the gear ratio can best be made by the addition to or elimination from the gear set of one or more gears. In certain instances it is, therefore, desirable to arrange the escape mechanism to accommodate rotation of the escape wheel 42 in either direction. Such an arrangement is shown in Figs. 24, 25 and 26, in which the pallet 44 is provided with a single radially projecting finger I22, the respectively opposite radial faces whereof correspond to the previously described shoulder I22. In addition, the pallet 44 is provided with two shoulders I24 and I24, which individually correspond to the shoulder I24 and which are symmetrically arranged at either side of the finger I22. The rotative position of the spring bracket I20 with respect to the pallet 44 and the mounting for the fixed end of the spring I48 are such that the spring 48 always tends to rock the finger I22 to a position in which it lies between and on a line with the axis of the pallet shaft 90 and the axis of the escape wheel 42.

As will be appreciated, Figs. 24 and 26 correspond, respectively, to Figs. 16 and 18, and the operation of the escapement, considering clockwise rotation of the escape wheel 42, is the same as previously described with reference to Figs. 16 and 18. If, however, the gearing is changed so as to produce counterclockwise rotation of the escape wheel 42,, the parts cooperate as shown in Fig. 25. That is to say, the tooth of the escape wheel bears against the righthand radial face of the finger I22 and urges the pallet 44 in a clockwise direction sufficiently far to bring the shoulder I24" into blocking relation to the next succeeding escape wheel tooth. The spring 48 opposes the just-mentioned rotation of the pallet 44 and swings the same in a counterclockwise direction, thereby releasing such next succeeding escape wheel tooth from the shoulder I24 and 18 allowing such tooth to advance and strike the finger I22 as just described. In other respects, the operation depicted in Fig. 25 is the same as previously described.

In Figures 27 and 28 is illustrated a further modification of the escapement, in which the escapement element, or pallet, is formed integrally with the balance staff and a slightly modi fied form of resilient escapement wheel is provided. As shown best in Figures 27 and 28, the balance staff is illustrated on a larger scale than in Figures 24 to 26. The balance staff 90', however, except for the details of the escapement element itself, hereinafter described, is similar in arrangement and construction to the balance stafi 90, previously described and illustrated. In this form of the invention, the escapement element or pallet 280 is similar in form to the element 44', illustrated in Figures 24 and 26, being provided with a pair of shoulders 28I forming braking surfaces, a pair of escape notches 282, and an intermediate radial projection 283 which extends radially to a substantially greater degree than the shoulders 28I and which receives the impulse from the escapement wheel. The escapement element 280, including the escapement notches and the radial projection 283, is formed integral with and from the balance stafl 90 by a stamping operation, in the manner illustrated in Figure 29. As shown in Figure 29, the balance staff 90 is placed between a pair of die elements 290 and 29I which, when forced together, form the notches 282 in the balance staff and extrude the metal which formerly occupied the notched spaces to form the radial projection or impulse member 283.

It will be observed that in the escapement element of Figures 27 and 28, as well as the escape ment element of Figure 24, the corner between the braking surface and the notch is rounded in the manner illustrated and described in connection with the pallet 44, illustrated in Figures 16 and 17, except that the notches and braking surfaces are duplicated in the reversible form of pallet.

The form of escapement element or pallet illustrated in Figures 27 and 28 may be used equally well with an escapement wheel of the form illustrated in Figures 24 to 26 or of the form illustrated in Figures 20 and 21. However, there is illustrated in Figure 27 a further modified form of escapement wheel 292 provided with a plurality of resilient teeth 293. The escapement wheel 29I is formed of sheet metal and has a flat central portion 294 secured in any suitable man ner to a hub 295, which is provided with pinion teeth 298 adapted to mesh with the teeth of gear I8 in the manner illustrated in Figure 7. The teeth 293 are formed integrally from the same sheet of metal as the central portion 294, and are initially 0f the width indicated in dotted lines at 291. However, after the Wheel is blanked out of the sheet metal, the teeth are twisted through an angle of 90 at the point 298 adjacent the bases so that the plane of the teeth extends parallel to or contains the axis of the wheel. This produces a relatively thin, fiat-bladed resilient tooth for cooperation with the escapement element 280 in the manner described in connection with the resilient escapement wheel illustrated in Figures 20 and 21.

It will be understood that the form of escapement wheel illustrated in Figure 27 may be substituted for the escapement wheel 42 in Figures 19 16 and 1'7 or for the escapement wheelAZin Figures 24' to26, if desired;

While several specific embodiments of the invention have been described in detail, it' will be appreciated that Various modifications in the form, number and arrangement of parts may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. An escapement mechanism comprising an oscillating balance staff, means directly on and movablewith said staff forming an escapement space permitting escapement of teeth successive- 1y; said means also having a braking surface associated therewith, and an escapement Wheel having peripherally arranged resilient teeth cooperating with said means mounted on the staff for escapement through said space, and cooperable with said braking surface prior to passage through said space.

2. An escapement mechanism comprising an oscillating staff, an escapement member mounted on and movable with the staff, said member having an'extension therefrom and a braking surface thereon with space therebetween, and an escapement wheel having peripherally arranged resilient teeth cooperating -resiliently with the braking surface of the escapement'member and passing through said space'into resilient cooperation with said extension for driving the latter.

3. An escapement wheel comprising peripherally arranged teeth, each of which consists'of a plane of springy material arranged as a cantilever, -said plane havin'g'an outer edge of substantial length which is substantially parallel to the axis of the wheel.

4. An escapement mechanism comprising an oscillating balance staff, 'means on said staff forming an escapement space permitting escapemerit of teeth successively, said escapement means also having an extension'and a braking surface associated therewith, and an escapement wheel having peripherally arranged resilient teeth cooperating resiliently with the braking surface of the resilient member and passing through said space and cooperating with said extension for driving the latter, the plane of resilient movement of said teeth being parallel tothe plane of movement of saidextension,

5. An escapement mechanism comprising a rotatable escapement wheel having a plurality of peripherally arranged teeth, an oscillating balance staff, and escapement means directly on and movable with said staff for permitting escapement of said teeth progressively, said means having a braking surface for successively engaging said teeth and a substantially radially projecting impulse surface adapted to be struck by each tooth as 'it is released from said braking surface, said braking surface and impulse surface being separated by a notch of sufficient sizelto permit pas'sag'eof one to'oth of said wheel at a time, said braking surface being a curved surface whose radius from the axis of said'means progressively decreases as the surface approaches said notch.

6. An escapement mechanism comprising a rotatable escapement wheel'having a plurality of peripherally arranged teeth, an oscillating balance staff, and escapement means directly on and movable with said staff for permitting escapement of said teeth progressively, said means having a braking surface for successively engaging said teeth and a substantially radially projecting impulse surface adapted to be struck by each tooth as it is released from said braking surface,

said braking surface and'impulse surface being separated by a notch ofsufficient size to permit passage of one'tooth of said wheelat a time, said braking surface being a curved surface whose radius from the axis of said means progressively decreases as the surface approaches 'saidnotch beginning with a curve approximately concentric to the axis of oscillation of saidmeans and terminating at said notch in a curve whose tangent is approximately perpendicular to the plane of said impulse surface.

7. An escapement mechanism comprising a-rotatable escapement Wh'eelhaving a plurality of peripherally arranged teeth, an'oscillating balance staff, and escapement means directly on and movable with said staff .for permitting escapement of said teeth progressively, said means having a braking surface for successively engaging said teeth and a substantially radially projecting impulse surface adapted to be struck by each tooth as it is released from said'braking surface, said braking surface and impulse surface being separated by a notch of sufficient size to permit passage of one tooth of said wheel at a time, said braking surface being a curved surface whose radius from the axis of said means progressively decreases as the surface approaches'said notch and said impulse surface projecting from said axis of oscillation a substantiallygreater distance than'any part of said braking surface.

3. An escapement mechanism comprising arotatable escapement wheel having a plurality of peripherally arranged teeth," an oscillating bal-t ance staff, and escapement means directly on and movable with said staff for permitting'es capement' of said teeth progressively, said means having a braking surfacefor successively engag-j ing' said teeth and asub'stantially radially pro- -je'cting impulse surface adapted'to be struck by each to'oth' as it is 'reIeased'fr'om said braking surfacepsaid braking surface andimpulse surface being'separa'ted by a notch of sufficient size to permit passage of one tooth of said wheel at a time said braking surface being a curyed sure face whose radius-fromthe axis of said means progressively decreases as the surface approaches said notchbeginning witha curve approximately concentricto the axis of oscillation of said means and terminating at said notchjin a curve whose tangent is approximatelyperpendicular to the plane ofsaid impulse surface and said impulse surface projecting from saidaxis of oscillation a substantially greater said braking surface.

9. A reversible escapement mechanism com-, prising a rotatable escapement wheel having a plurality of peripherally arranged radially pro- J'ec'tin'g teeth, an oscillating balance staff :lhaving' a radial projection defining a pair of oppositely; directed substantially radially-extending impulse surfaces, one impulse surface beingadapted'to be engaged successively by said teeth whensaid Wheel is rotating in one direction and the'other e di b nga e sucq lyrbr a e h when said wheel is rotating in the other direction, said element havin a notch formed therein at each side of said projection, one notch being adapted to permit p'assage of oneofsaid teeth at a time into contact with said projection when the'wheel rotates in one direction and theother notch being adapted, to permitsuch passage of one of said teeth at a time into contact with'said projection when the Wheel rotates in the 'opposite distance than part :or

direction, and said element having at the opposite sides of each notch from said projection a braking surface adapted when the element is in one rotative position to engage one of said teeth and interrupt the movement of said tooth toward the projection and adapted to permit movement of said tooth through the notch and into engagement with said projection when the element is in another rotative position, one of said braking surfaces being operative when the wheel is rotating in one direction and'the other braking surface being operative when the wheel is rotating in the opposite direction, and a spring eccentrically connected to said balance staff and having a dead center position when said projection extends toward the axis of said wheel.

10. A reversible escapement mechanism comprising a rotatable escapement wheel having a plurality of peripherally arranged radially projecting teeth, an oscillating balance staff having an escapement element fixed to said balance staff and having an integral radial projection defining a pair of'oppositely directed substantially radially extending impulse surfaces, one impulse surface being adapted to be engaged successively by said teeth when said wheel is rotating in one direction and the other adapted to be engaged successively by said teeth when said wheel is rotating in the other direction, said balance staff having a notch formed directly therein at each side of said projection, one notch being adapted to permit passage of one of said teeth at a time into contact with said projection When the Wheel rotates in one direction and the other notch being adapted to permit such passage of one of said teeth at a time into contact with said projection when the wheel rotates in the opposite direction, and said balance staff having at the opposite sides of each notch from said projection a braking surface adapted when the balance staff is in one rotative position to engage one of said teeth and interrupt the movement of said tooth toward the projection and adapted to permit movement of said tooth through the notch and into engagement with said projection when the balance staff is in another rotative position, one of said braking surfaces being operative when the wheel is rotating in one direction and the other braking surface being operative when the wheel is rotating in the opposite direction, and a spring eccentrically connected to said balance staff and having a dead center position when said projection extends toward the axis of said wheel,

11. A unitary balance staff and escapement element comprising a generally cylindrical shaft having a radial projection formed integrally therewith, said shaft having notches at each side of the projection adapted to act as escapement spaces.

12. An escapement mechanism comprising an oscillating balance staff, a shaft extending parallel to said staff, an escapement wheel on said shaftesaid wheel having a central sheet metal web portion and resilient peripheral teeth projecting substantially radially from said web portion and integral with said Web portion, means directly on and movable with said staff defining a peripheral braking surface adapted in one rotative position of said stafi to engage the extremity of one of said teeth and block movement of said wheel, said means defining the braking surface being adapted on rotation of said staff in one direction from said position to release said tooth and permit rotation of said wheel, a spring acting to rotate said staff in said one direction when said braking surface is in engagement with a tooth of said wheel, and means directly on and movable with said staff forming a substantially radially projecting impulse surface in a position to be engaged by the extremity of each tooth of said Wheel when the tooth is released from said braking surface and to be moved by the tooth in a direction to rotate said staff in the opposite direction into the position in which said braking surface engages the next succeeding tooth of said wheel.

13. An escapement mechanism comprising an oscillating balance staff, a shaft extending parallel to said staff, an escapement wheel on said shaft, said wheel having a central sheet metal web portion and resilient peripheral teeth projecting substantially radially from said web portion and integral with said web portion, means directly on and movable with said staif defining a peripheral braking surface adapted in one rotative position of said stafi to engage the extremity of one of said teeth and block movement of said wheel, said means defining the braking surface being adapted on rotation of said staif in one direction from said position to release said tooth and permit rotation of said wheel, said peripheral braking surface terminating adjacent the releasing extremity thereof in a peripheral braking surface of progressively decreasing radius from the axis of said staff to effect a gradual release of said tooth as said staff rotates in said one direction, a spring acting to rotate said staff in said one direction when said braking surface is in engagement with a tooth of said wheel, and means directly on and movable with said staff forming a substantially radially projecting impulse surface in a position to be engaged by the extremity of each tooth of said wheel when the tooth is released from said braking surface and to be moved by the tooth in a direction to rotate said staff in the opposite direction into the position in which said braking surface engages the next succeeding tooth of said wheel.

14. An escapement mechanism comprising a rotatable escapement wheel having a plurality of peripherally arranged teeth, an oscillating balance staff, and escapement means directly on and movable with said staff for permitting escapement of said teeth progressively, said means having a peripheral braking surface for successively engaging said teeth and a substantially radially projecting impulse surface adapted to be struck by each tooth as it is released from said braking surface, said braking surface and impulse surface being separated by a notch of sufficient size to permit passage of one tooth of said wheel at a time, said braking surface being a curved surface having a portion adjacent said notch whose radius from the axis of said means progressively decreases as the surface approaches said notch beginning with a curve approximately concentric to the axis of oscillation of said means and terminating at said notch in a curve whose tangent is approximately perpendicular to the plane of said impulse surface,

15. An escapement mechanism comprising an oscillating balance staff, a shaft extending parallel to said staff, an escapement wheel on said shaft and having peripheral teeth extending substantially radially therefrom, means directly on and movable with said staff defining a peripheral braking surface adapted in one rotative position of said. staff to engage the extremity of one of mit rotation of said wheel, saidperlpheral bra-k- 5 ing surface. terminating adjacent the releasing extremity thereofin a peripheral braking surface of progressively decreasing radius from, the axis of said stafi to permitagradualrelease of said tooth as said staff rotates in said one direc tion, a spring acting to rotate said stafi in said one direction when said braking surfaceis in engagement with a tooth of said wheel, and means directly on and movable with said staff forming a substantially radially,pnpjecting impulse surface extending radiallyto a reaterextent than the maximum radius of said; braking surface and adapted to be engaged by'ea ohtoothof said wheel when the tooth is releasedfrom saidbraking surface and to be moved by the tooth in a direction to rotate said staff inthe opposite directionto shift said stafi" into the position in which said braking surface-engages the-next succeeding tooth of said wheel.

CHARLES E. GODLEY.

REFERENCES CITED.

The. following references are of record in the file-of this patent:

UNITED STATES PATEN TS Number A- Name Date.

1,934,611 Franz Nov. 7, 1933 1,4u1'L58Z- Calvert Mar. .6, 1923 328,308 Hart Oct. 13, 1885 2,150,633: Rhodes et a1 Mar. 14, 1939 1,398,776 .Greenwald Nov, 29; 1921 797,730 .Gundorph Aug. 22, 1905 1,861,947 Kohler- July.19, 1932 1,895,398: Rhodes Jan. 24, 1933 1,995,363 Rhodes Mar. 26,1935

FOREIGN PATENTS Number Country Date 27,413- Denmark Apr.;18,' 1921 OTHER- REFERENCES Horological Review Publication of Oct. i 1916, pages 129 and. 131.

Scientific American Supplement of June. 10, 1905, pages 24,616 and 24,617.

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