US2618118A

US2618118A - Watch movement

Info

Publication number: US2618118A
Application number: US107038A
Authority: US
Inventors: Wilbur T Harris; Francis R Mcaloon
Original assignee: United States Time Corp
Current assignee: United States Time Corp
Priority date: 1949-07-27
Filing date: 1949-07-27
Publication date: 1952-11-18
Anticipated expiration: 1969-11-18

Description

l A l I i 2 -L l I 1 INVENTORS.

WILBUR T. HARRIS FRANCIS R. MCALOON 5W ATTORNEY.

2 SHEETS-SI-IEET l W. T. HARRIS EI'AL WATCH MOVEMENT Nov 18, 1952 Filgad July 27, 1949 Nov. 18, 1952 w. r. HARRIS ETAL 2,618,118

WATCH MOVEMENT Filed July 27, 1949 2 SHEETS-SHEET 2 If) 92 W I I 74 90 64 as 84 I INVENTORS. 84 WILBUR T. HARRIS F iucls R. McAL-OON %OQ'W ATTORNEY.

Patented Nov. 18, 1952 Wilbur T. Harris, Southbury, and Francis R. McAloon, Waterbury, Conn., assignors to The United States Time Corporation, Middlebur-y, Conn, a corporation of Connecticut Application July 27, 1949, Serial No. 107,038

6 Claims.

.This invention relates to improvements in watch movements and more particularly pertains to improvements in that part of the movement for supporting and actuating a central sweep second staff. Further, but without restriction thereto, the invention relates to mechanism of this nature suitable for use in an inexpensive watch.

Heretof'or'e in watches generally, and particularly in inexpensive watches, when it has been desired to provide sweep-type second hands which are pivotally mounted so as to be concentric with the center arbor of a watch, additional components have been required; and in order that the cost of providing'such additional components would be maintained at a minimum, such additional components were for the most part added to the frame adjacent the exterior surface of the rear frame plate, thus increasing the overall thickness of the movement and consequently addingto the overall thickness of the watch.

In certain popular inexpensive watch movements, the sweep second staff is mounted in a tubular center arbor and the end of the sweep second staffwhich is disposed adjacent the rear name plate is provided with a small pinion. Said pinion is driven by a relatively very large gear wheel mounted in a so-called outboard posi-' tion adjacent the rear frame plate and fixed to the outer end of" the third wheel staff which projects through said rear frame plate. Such outboard wheel is supplementary to the usual third wheel of the watch movement which is also mounted on said staff between the frame plates.

use: of such a. large gear wheel to drive the sweep second pinion is necessary to span the distance between the third wheel staff and center arbor and secure the necessary gear tooth ratio. Generally, said large gear wheel has an even greater diameter than the usual third wheel fixed to the, same staff, whereby'the size of the move ment has to be relatively large to accommodate such a large gear wheel within the perimeter of the-frame plates. Further, appreciable clearance between said wheel and the rear frame plate is required in order to allow for a'certain amount of cooking of said wheel realtive to the third wheel staff without having the rim or teeth of the gear wheel engage the rear frame plate. A substantialamount of such cocking is inescapable whenusing manufacturing methods such as are necessary when producing inexpensive" watches. Unless such clearance is provided,- inspection costs are materially increased to insure that each such gear wheel ismou'nted on the third wheel staff with substantially perfect perpendlculan-ty.

It is also to be noted that in inexpensive watches, it has heretofore been customary to provide substantially flat frame plates each having only a single level in order that the cost of producing the plates could be maintained at a minimum. In view of the foregoing,- the overall thickness of such inexpensive movement and watch has been substantially in excess of that of more expensive watches in which multiple levels are provided within the movement, such multiple levels permitting considerable decrease in the thickness of the movement and watch.

In general, the cost of providing a central sweep second hand on an inexpensive watch has presented sufficie'ntly great mechanical operation and cost difficulties that most inexpensive watches have not had such sweep second hands and have used instead a conventional second hand disposed on the lower or upper portions of the dial in the vicinity of the numerals 12 or '6 thereon. In these circumstances, said second hand is fixed directly to an extended end of the fourth wheel staff. Such construction materially limits gear ratios in the time train as well as positions of the fourth wheel staff. Substantially no variance in either said ratio or position of the fourth wheel staff has been possible in situations where variations therefrom may have been desir able, for example, for purposes of rendering the movement more compact and smaller in overall dimensions.

The added cost of providing sweep second hands in inexpensive watches has been mainly due to the cost of the required number of additional components referred to in the foregoing as well as using a tubular center arbor in which the sweep second staff was rotatably mounted. Production of tubular center arbors suitable for use in inexpensive watches having sweep second staffs is costly due to the high degree of precision, and consequent inspection costs, required to insure satisfactory mechanical performance of the arbor and sweep second staii when mounted therein.

It is an object of the present invention to pro vide an inexpensive watch movement which may be made thinner than the conventional inexpensive movement.

It is another object of the invention to inexpensively provide multiple levels in a watch movement which may be advantageously utilized for purposes of rendering the movement thinner as well as affording means for embodying: sweep second mechanism in the movement without ap= preciably increasing the cost of production thereof.

It is a still further object of the invention to so arrange the components of the time train that the sweep second pinion is driven by the third wheel of the time train, thus eliminating the need for additional gears or wheels to drive the sweep second pinion as has heretofore been customary in attempts to produce an inexpensive sweep second watch movement.

Details of these objects and of the invention as well as other objects thereof are set forth in the following specification and illustrated in the accompanyin drawings comprising a part thereof.

In the drawings:

Fig. 1 is a fragmentary sectional side elevation of a watch movement embodying the principles of the invention.

Fig. 2 is a perspective view of one embodiment of a component of the invention illustrated in Fig. 1.

Fig. 3 is a fragmentary, sectional side elevation of a watch movement illustrating another embodiment of the component shown in Fig. 2.

Fig. 4 is a view similar to Fig. 3 illustrating a still further embodiment of the component of the invention shown in Fig. 2.

Fig. 5 is a view similar to Fig. 3 illustrating a modification of the invention in which it is not necessary to provide a separate component such as shown in Fig. 2.

Fig. 6 is a plan view of the rear frame plate of a watch movement embodying the form of the invention shown in Fig. 5.

In inexpensive watch movements, it is generally recognized that the least expensive type of construction is that using a pair of spaced, substantially planar frame plates mounted in parallel relation, said plates being provided with pierced bearing apertures which rotatably support the various components of the movement. In the present drawings, and particularly Fig. 1, it will be seen that the movement frame comprises a front frame plate Ill and a rear frame plate 12 which are fixed in spaced relationship by a plurality of suitable conventional pillars, not shown. Substantially centrally of the rear frame plate an enlarged aperture Hi is provided for purposes to be described.

The inner surface of the rear frame plate is also preferably subjected to a sweeping, or end milling, operation to provide a recess 15 which accommodates the open end of the barrel 18. The barrel is mounted on the barrel arbor which also supports barrel gear 22. The barrel and barrel gear are rotatably driven relative to the frame by the mainspring within the barrel. Front frame plate It is also provided substantially centrally thereof with a bearing aperture 24 which rotatably receives the tubular center arbor 26. The portion of the arbor which engages the bearing 24 has a diameter larger than the other portions of the arbor in this particular movement. Variations from this arbor configuration are possible.

Secured to center arbor 26 Ba cannon pinion 28. Minute hand 30 is press fitted to the outer end of center arbor 26. Rotatably mounted on the forward end of center arbor 26 is hour socket 32 to which hour hand 34; is secured as well as the hour gear wheel 36. Differential gear 38 and pinion 40 are mounted on a short stub shaft 42 and connect hour gear wheel 36 and cannon pinion 28 to give the customary 12:1 ratio of movement between the minute and hour hands.

Center pinion 44 is also rotatably mounted on center arbor 26, and secured to said pinion is a 4 center wheel 46 which moves as a unit with said inion. The inner surface of frame plate In is preferably provided with a circular broad shallow recess 41, formed by a sweeping or end milling operation and resembling recess l6 of frame plate I2, to accommodate center wheel 46 and permit the movement to be consequently thinner. There is also fixed to the center arbor a disc 58 providing a collar against which pinion 44 abuts. Disposed between center wheel 46 and annular shoulder 50 on the center arbor is a spring washer 52 which frictionally connects the center pinion 44 with the center arbor 26, whereby the barrel gear 22 which meshes with said center pinion 44 will also drive the center arbor 26. The friction afforded by washer 52 can be overcome to permit movement of the center arbor relative to the center pinion M and center wheel 48 when it is desired to set the hands of the watch. It will also be seen from Fig. 1 that center wheel 46 drives third wheel pinion 54 as well as third wheel 56 which are both secured to the third wheel staff 58 rotatably mounted in suitable bearings in the frame plates 10 and I2.

The opposite ends of center arbor 26 are constricted, as will be readily seen from Fig. 1, for purposes of providing at the opposite ends thereof annular knife edge-type bearings 69 and 62 comprising part of the subject matter of co-pending application Serial No. 11,177, filed February 26. 1948, now abandoned, and assigned to the assignee of the present application. Bearings Y and E2 rotatably support sweep second staff '64 which extends at its ends beyond the ends of the center arbor 2E. The forward end of sweep second staff as also supports hub 66 of sweep second hand 68. The rearward end portion of staff 64 has fixed thereto sweep second pinion 10 which meshes with third wheel 56, whereby the third wheel drives the sweep second staff in addition to driving the conventional fourth wheel pinion of the movement, said pinion not being shown in the present disclosure. In view of this dual function of third wheel 56, an economy in components is effected to reduce the cost of the movement while providing it with a sweep second hand centrally thereof.

Mounted within aperture M in rear frame plate 52 is a cup-shaped potence 12 which is preferably formed by stamping or pressing from sheet metal so as to have walls of substantially uniform thickness as well as reduce the cost of production. The potence is also provided at its rim with a flange i i that is disposed against the outer surface of rear frame plate [2, said flange preferably being produced simultaneously with the formation of the potence. The side portion of the potence adjacent the rim thereof frictionally engages the walls of aperture M to retain the potence in operative position relative to the frame plate. The potence may be provided, if desired, with a slightly tapered side surface 16 adjacent the inner end or bottom thereof to facilitate inserting the potence within the aperture 14.

The bottom of the cup of the potence i also provided substantially centrally thereof with a bearing aperture 13 which receives and supports the rearward end of center arbor 26. It will thus be seen that the center arbor is provided with a plurality of spaced

bearings

24 and 78 which afford firm means to rotatably support the center arbor relative to the movement.

Due to the use of the potence 12, the bottom thereof provides an additional level for the rear frame plate in order that the center arbor 26 may be terminated at its rearward, end inwardly of the movement, whereby the rearward end of the staff 64 and sweep second pinion may also be disposed inwardly of the rear frame plate as distinguished from being mounted in an outboard position relative thereto. This feature is important in the present invention both from the standpoint of reducing the cost of producing a sweep second hand construction and decreasing the thickness of the movement.

Co-eng'agement between the teeth of sweep second pinion T0 and third wheel 56 is possible due to an opening 80, produced by milling or otherwise, in a portion of the side wall of the potence 12 adjacent the bottom thereof. The rim of third wheel 56 moves within said opening.

In order that the hub 66- of the sweep second hand may not engage or otherwise interfere with the movement of the minute hand 30, a space is maintained between said minute hand and hub by biasing sweep second pinion 10 against the rearward end of the center arbor 28 as is clearly shown in Fig. 1. It will be observed that said rearward end of the center arbor is not only provided on its interior with a knife edge bearing 62', but the exterior of the end of said arbor is provided with a circular knife edge thrust bearing 82 which slidably engages the inner end surface of pinion 10. A minimum of friction therefore results between the end of the center arbor and pinion 10.

The pinion I0 is biased against the inner end of center arbor 29 by suitable means such as a leaf spring 84 which is secured to the outer surface of frame plate l2 by any appropriate means such as screws, rivets, or spot welding, none of which are shown in the drawing. The spring 84 need not be strong due to the light force it needs to exert in order to maintain the sweep second staff in its operative position relative to the center arbor. 'I'hus, said spring imposes no appreciable burden on the time train of the watch due to the frictional engagement of the spring with the end of sweep second staff 64. In order that the spring 84 may engage the rearward end of staff 64 without appreciably increasing the thickness of the movement, the rim of the potence 72 is provided with a. notch 86, said notch continuing through the adjacent portion of the flange 14 as is clearly shown in Figs. 1 and 2. Said notch accommodates the spring 84 and thus permits it to engage the rearward end of the staff 64 without the spring extending to any appreciable extent beyond the outer surface of the flange 14 of the potence as is clearly shown in Fig. 1.

The foregoing relates to one embodiment of potence which may be utilized in the construction of the type described. The potence shown in Fig. 1 is'also shown in perspective view in Fig. 2, while in Figs. 3 and 4, two different embodiments of potence which may be used are illustrated.

The potence shown in the embodiment in Fig. 3 is substantially the same as the potence 14 of Figs. 1 and 2 but in order to provide additional support for the extreme rearward end of staff 64, a disc-like member 88 having a central bearing aperture 90 is mounted within the open end of her 88 relative to the potence, an annular seat 92 may be provided therefor. Further, the press fit between the rim of member 88 and the inner surface of the potence may be such that the engagement of the member 88 with the rim of the potence 12 will force the outer surface of the rim of the potence into greater frictional engagement with the surface of the aperture [4 in the rear frame plate I2. Thus, any need for screws or other means for securing the potence to the rear frame plate is eliminated.

Referring to a still further embodiment shown in Fig. 4, it will be noted that the potence 12' is provided on its outer side wall with a flange 14' positioned between the outer edge or rim of the potence and the bottom thereof in order that flange 14 may be disposed against the inner surface of frame plate l2 as distinguished from the outer surface of the frame plate which is engaged by flange 14 in the embodiments shown in Figs. 1 through 3. A slight additional recess 15 is formed on the inner surface of frame plate 12 to accommodate flange 74', the recess 19 merging with recess I6. The bottom surfaces of recesses ['6 and 15 are considered to be part of the inner surface of frame plate 12. The rim of the potence 12', however, is provided with a notch 86' for purposes of accommodating the spring 84.

The potence 12 is also provided with a disc-like the member 83 be press-fitted into potence 12 in such a manner that the outer surface of the rim of the potence is forced into firm frictional engagement with the walls of aperture 14 in order that the potence may be securely assembled to the frame plate 12. However, under these circumstances, the flange M will serve to properly position the potence relative to the frame plate.

In the modification of the invention shown in Figs. 5 and 6, the advantages heretofore describedare secured without using a separate piece of material for the formation of the potence. In the modified form of the invention, the potence is formed integrally with the rear frame plate 12. As shown in Fig. 6, the central aperture 98 is so formed as to leave a tongue 96. The tongue 96 is bent in a direction to extend into the movement as shown in Fig. 5, and the inner end 94 thereof is bent into a plane parallel with the plane of the rear frame plate. The latter portion 94 is provided with an aperture I00 which serves as a rotatable bearing for the inner end of the center arbor 28. Preferably, the portion 94 is made thinner as by milling a depression I02 therein to receive the sweep second staff pinion 10.

The sweep second staff '64 and the pinion l0 fixed thereto, are positioned as described in connection with the previous modifications so that the pinion l0 meshes with the third wheel 56. The spring 84 attached to the outer surface of the rear frame plate l2 serves to hold the pinion 10 in abutting relation with the inner end of the arbor 26.

Due to the feature of directly driving the sweep second staff pinion 10 by the conventional third wheel of the movement, the overall area as well as thickness of the movement is materially reduced as compared to a movement provided with either an outboard large gear wheel to drive an outboard sweep second pinion or a second hand fixed to the fourth wheel staff, the second hand in this instance being disposed on the dial in the vicinity of the numerals 6 or 12 on the dial. Providing a Watch with a sweep second hand, such as in the present invention, and particularly one driven directly by the conventional third wheel of the movement, also permits great latitude of positions for the third, fourth, and escape wheel staffs where desired for compacting the movement to render the area smaller than movement wherein a non-sweep second hand is secured to the fourth Wheel staff.

While the invention has been illustrated and described in its preferred embodiments and has included certain details, it should be understood that the invention is not to be limited to the precise details herein illustrated and described since the same may be carried out in other ways, falling within the scope of the invention as claimed.

What we claim is:

1. In a Watch movement having a rear frame plate provided with an aperture substantially centrally thereof, the combination of a tubular center arbor rotatable relative to said movement in axial alignment with said aperture, a, sweep second staff rotatable within said center arbor and having its ends extending beyond the ends of said arbor, one end of said staff being disposed adjacent said rear frame plate, pinion fixed to said one end of said staff and abutting the adjacent end of said center arbor, a cup-shaped potence disposed within said frame plate aperture and having its rim positioned adjacent the outer surface of said frame plate and its bottom extending into movement from said frame plate, the bottom of said potence being aper-tured to provide a bearing rotatably receiving one end of said center arbor and the rim of said potence being notched, and a spring fixed relative to said frame plate and extending into said notch in said potence rim to engage said one end of said staff and bias said pinion thereon against said adjacent end of said center arbor.

2. In a Watch movement having a rear frame plate provided with an aperture substantially centrally thereof, the combination of a tubular center arbor rotatable relative to said movement in axial alignment with said aperture, a sweep second staff rotatable within said center arbor and having its ends extending beyond the ends of said arbor, one end of said staff being disposed adjacent said rear frame plate, a pinion fixed to said one end of said staff and abutting the adjacent end of said center arbor, a cup-shaped ,5 potence disposed within said frame plate aperture and having its rim positioned adjacent the tence rim to engage said one end of said staff and bias said pinion thereon against said adjacent end of said center arbor.

3. In a watch movement having a rear frame plate provided with an aperture substantially centrally thereof, the combination of a tubular center arbor rotatable relative to said movement in axial alignment with said aperture, a sweep second staff rotatable within said center arbor and having its ends extending beyond the ends of said arbor, one end of said staff being disposed adjacent said rear frame plate, a pinion fixed to said one end of said staff and abutting the adjacent end of said center arbor, a cup-shaped potence disposed within said frame plate aperture and having its rim positioned adjacent the outer surface of said frame plate and its bottom extending into the movement from said frame plate, the bottom of said potence being apertured to provide a bearing rotatably receiving one end of said center arbor and the rim of said potence being notched and except at said notch being provided with a flange disposed against the outer surface of said frame plate, and a spring fixed relative to said frame plate and extending into said notch in said potence rim to engage said one end of said staff and bias said pinion thereon against said adjacent end of said center arbor.

4. In a watch movement having a rear frame plate provided with an aperture substantially centrally thereof, the combination of atubular center arbor rotatable relative to said movement in axial alignment with said aperture, a sweep second staff rotatable within said center arbor and having its ends extending beyond the ends of said arbor, one end of said staff being disposed adjacent said rear frame plate, a pinion fixed to said one end of said staff and abutting the adjacent end of said center arbor, a cup-shaped potence disposed within and frictionally engaging the walls of said frame plate aperture and having its rim positioned adjacent the outer surface of said frame plate and its bottom extending into the movement from said frame plate-the bottom of said potence being apertured to provide a bearing rotatably receiving one end of said center arbor and the rim of said potence being notched, a flange on the exterior of said potence disposed against the inner surface of said frame plate, and a spring fixed relative to said frame plate and extending into said notch in said potence rim to engage said one end of said staff and bias said pinion thereon against said adjacent end of said center arbor.

5. In a watch movement having a rear frame plate provided with an aperture substantially centrally thereof, the combination of a tubular center arbor rotatable relative to said movement in axial alignment with said aperture, a sweep second staif rotatable within said center arbor and having its ends extending beyond the ends of said arbor, one end of said staff being disposed adjacent said rear frame plate, a pinion fixed to said one end of said staff and abutting the adjacent end of said center arbor, a cup-shaped potence disposed within said frame plate aperture and having its rim positioned adjacent the outer surface of said frame plate and its bottom extending into the movement from said frame plate, the bottom of said potence being apertured to provide a bearing rotatably receiving one end of said center arbor and the rim of said potence being notched, a flange on the exterior of said potence disposed against the inner surface of said frame plate, a member press-fitted into said potence adjacent the rim thereof to force the potence into firm frictional engagement with the walls of said frame plate aperture, said member being provided with a bearing aperture pivotally receiving said one end of said staff, whereby said pinion is disposed between said member and the bottom of said potence, and a spring fixed relative to said frame plate and extending into said notch in said potence rim to engage said one end of said staff and bias said pinion thereon against said adjacent end of said center arbor.

6. In a watch movement of the full plate type having a generally planar rear frame plate provided with an enlarged aperture substantially centrally thereof, a front frame plate provided with a bearing aperture substantially centrally thereof, the combination of a tubular center arbor rotatable relative to said movement in the bearing aperture in said front frame plate and in axial alignment with the enlarged aperture in said rear frame plate, a sweep second staff rotatable within said center arbor, one end of said center arbor extending through said front frame plate to carry a hand and the corresponding end of said sweep second staff extending beyond said center arbor to carry a hand, the other end of said arbor terminating within said movement and the corresponding end of said sweep second staff terminating adjacent said rear frame plate, a pinion fixed within said movement near said last named end of said sweep second staff and adapted to abut against said last named end of said center arbor, a potence comprising a tongue of said rear frame plate material and displaced from the plane thereof so as to extend into said movement from the enlarged aperture in said rear frame plate, said potence having a portion parallel with said rear frame plate apertured to provide a bearing rotatably receiving said last named end of said center arbor, and a spring carried by said rear frame plate engaging said last named end of said sweep second stafi to bias said pinion against said last named end of said center arbor.

WILBUR T. HARRIS.

FRANCIS R. MCALOON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 199,392 Woerd Jan. 22, 1878 220,815 Earl Oct. 21, 1879 2,192,272 Puthod Mar. 5, 1940 FOREIGN PATENTS Number Country Date 131,857 Switzerland May 16, 1929- 188,929 Switzerland Apr. 16, 1937 216,726 Switzerland Dec. 16, 1941 226,488 Switzerland July 16, 1943