US3016685A

US3016685A - Electric watch

Info

Publication number: US3016685A
Application number: US792014A
Authority: US
Inventors: James H Reese
Original assignee: Hamilton Watch Co
Current assignee: Hamilton Watch Co
Priority date: 1959-02-09
Filing date: 1959-02-09
Publication date: 1962-01-16
Anticipated expiration: 1979-01-16
Also published as: CH404558A; CH1230162A4; CH402744A; CH117560A4

Description

Jan. 16, 1962 J. H. REESE 3,016,685

ELECTRIC WATCH Filed Feb. 9, 1959 2 Sheets-Sheet 1 was A 35 5s:

INVENTOR BY I fiwmufga fe flw ATTORNEYS J. H. REESE ELECTRIC WATCH Jan. 16, 1962 2 Sheets-Sheet 2 Filed Feb. 9, 1959 C/WE': 665.15

INVENTO.

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United States Patent Ofiice 3,016,685 Patented Jan. 16, 1962 This invention relates to battery operated electric watches and more particularly relates to an improved contact and index system for such watches.

In electric wrist watches of the moving coil type which have been proposed and in the commercial electric wrist watch of the assignee, it has been customary to provide periodic energization to the coil by means of some type of spring-type commutating system. One such system is illustrated in assignees patent to J. A. Van Horn et al. No. 2,806,908. The proper operation of this type of contact system is absolutely essential to the successful performance of the watch and it has been found'that some criticality of adjustment exists.

According to the present invention, it has now been found that it is possible to entirely eliminate this type of spring-type contacting system and to utilize the indexing function of the balance wheel to perform the switching operation during, the time that it indexes. That is to say, in a battery operated electric watch of the aforementioned type, the balance wheel serves as the source of motive power and it is necessary to provide an indexing mechanism which receives power from the oscillating movement of the balance wheel and transforms these oscillations into rotary movement in one direction. Generally speaking, this has been accomplished by means of a toothed wheel which is advanced step by step by means of a periodic contact with a camming member carried by the balance Wheel.

In the present invention, the very energy which is required to advance the toothed index wheel is also utilized to provide an electrical contact without any requirement for the expenditure of additional energy. Because of the unique arrangement of the contact system, adjustment is entirely eliminated, thereby obviating the criticality previously mentioned. Fewer parts are required in that the entire spring-type contact system is done away with, thereby permitting a space reduction which makes possible a thinner watch movement. In addition to this, it is found that the contact which is obtained is more reliable than that which is possible with the spring-type contact system.

It is accordingly a primary object of the present invention to provide an improved contact and index system for an electric watch.

It is another object of the invention to provide an improved contact and index system for an electric watch of the type utilizing an oscillating balance staff to im part one-way motion to an index wheel wherein the energy required to advance the index wheel is also utilized to provide the periodic electrical contact.

It is another object of the invention to provide an improved contact and index mechanism for an electric watch wherein adjustment of the contact system is substantially eliminated.

It is another object of the invention to provide an improved contact and index system for an electric watch utilizing fewer parts than were heretofore found necessary.

It is still another object of the present invention to provide an improved contact and index system for an electric watch which permits a reduction in the size of the watch to provide a thinner watch movement.

It is still a further object of the invention to provide an improved contact and index system which produces more reliable contact than that obtainable heretofore.

These and further objects and advantages of the present invention will become more apparent upon reference to the following specification and claims and appended draw ings wherein:

FIGURE 1 is a partial vertical section of an electric watch showing the combined contact and index system of the present invention;

FIGURE 2 is a diagrammatic plan view showing the commencement of the index and contact cycle;

FIGURE 3 is a diagrammatic plan view showing the termination of the index and contact cycle;

FIGURE 4 is a diagrammatic plan view showing the return movement of the balance stat: wherein neither contacting nor indexing occurs; and

FIGURE 5 is a diagrammatic plan view showing another embodiment of the contact and index system.

Referring to FIGURE 1, there is seen a pillar plate 10 which, in conjunction with a bridge, not shown, carries a balance staff 12. The balance staff 12 carries a balance wheel on which there is mounted a coil of the general type shown in the aforementioned Van Horn et al. Patent No. 2,806,908. Also attached to the balance staff 12 is an index roller 14 Which may comprise a split collar of the type shown in the Van Horn et al. patent. A'

semi-cylindrical jewel pin 16- is mounted in the index roller and extends downwardly below the lower surface thereof as seen in FIGURE 1.

Referring now to both FIGURES l and 2, a contact 18 is attached to the jewel pin 16 in any suitable manner, such as by means of an adhesive. This contact 18 has a cutaway diagonal edge 20 and a vertical end 22. The portion of the contact attached to the jewel pin 16 has a semi-circular extension 24 which extends around the balance staff 12 out of contact therewith and passes up through an aperture 26 insulation 28 is provided between the contact and the index roller and may consist of an insulating adhesive or a synthetic resin. The contact itself preferably consists of a precious or semi-precious alloy compound having good conductivity characteristics and may, as an example, be formed of a gold alloy.

Referring again to FIGURE 1, the pillar plate 10 and a train bridge 30

support bearings

32 and 34 and an index assembly shown generally at 36. This index assembly consists of an index pinion 38 and staff 40, an index wheel collet 42, and a contact pivot 44. The index pinion staff 40 may be frictionally received in the metal collet 42 and this is brazed or welded to the pivot 44 which extends through the bearing 34. The pivot is preferably formed of a precious or semi-precious metal alloy and engages a similar precious or semi-precious alloy contact pad 46 carried by a battery lead 48 mounted below the pillar plate and secured thereto in any suitable manner, not shown.

The collet 42 carries a composite index wheel indicated generally at 50 consisting of an upper toothed alloy contact wheel 52 and a lower toothed magnetic index Wheel 54. The teeth on both wheels are in alignment with one another and extend into the path of movement of the jewel pin 16 and contact 18 carried by the balance staff 12.

A small cylindrical index magnet 56 is frictionally carried by the pillar plate 10 beneath the index wheel 50 and acts upon the magnetic index wheel 54 to pull the index assembly 36 downwardly so that the pivot 44 maintains continuous electric contact with the pad 46 on the battery lead i8. This magnet also serves a detent and drive function as presently will be explained.

In an electric watch of the type illustrated in Van Horn 1 et al. Patent No. 2,806,908, it is desired to provide elecin the index roller 14. Suitable tric energization to the balance stalf carried coil during a short period of time as the balance wheel and staff oscillate in one direction. During the return oscillation, it is ordinarily desired that no contact be made, although it is possible to design electric watches to operate with an impulse in both directions. The instant contact and index system is designed to transform the oscillating motion of the balance staff into one-way rotary motion of the composite index wheel 50 and to cause a limited time duration energization of the coil'carried by the balance staff as the balance staff oscillates in one direction only. Indexing of the index wheel is carried out during this oscillation.

Referring to FIGURE 2, the balance staff is shown rotating or oscillating in the direction indicated by the arrow A and the jewel pin 16, contact 18, index wheel 50 and index magnet '56 are shown in greatly magnified size. The position of the index wheel 50 seen in FIGURE 2 is an at rest position wherein a tooth 58 is centered over the index magnet 56 and is held by magnetic attraction between the magnet and the underlying magnetic tooth of the index wheel 54. According to a preferred embodiment of the invention the teeth of the composite index wheel 50 are provided with edges 60 which lie on diameters of the center of the index wheel. The trailing edges 62 of the teeth form acute angles with these leading edges.

In FIGURE 2, as the balance staff and index roller 14 rotate in the direction of the arrow A, the diagonal edge 20 of the contact 18 engages the tip of a tooth 64. This establishes a contact to one terminal of the balance staff carried coil as follows: From the battery, not shown, through battery lead 48, contact pad 46, pivot 44, collet 42, contact index wheel 52, contact 18, and contact lead 24 to the coil. The other side of the coil may be grounded to the watch frame in any suitable manner, such as by connection to the hairspring.

As the balance staff 12 and index roller 14 rotate in the direction of the arrow A the contact drives the index wheel against the holding force of the index magnet 56 until the index wheel reaches the position shown by the broken lines at 66 in FIGURE 2 and as illustrated in FIGURE 3. Referring now to FIGURE 3, the contact 18, index jewel 16 and index wheel 50 are shown in the positions represented by the broken line 66 in FIGURE 2. This represents the end of the contact period whereupon further movement of the balance staff and index roller in the direction of the arrow A will cause termination of the contact between the tooth 64 and diagonal edge 20 of contact 18.

It is to be noted that in this position (FIGURE 3), the tooth 64 is closer to the center of the index magnet 56 than is the tooth 58. Because of this, the magnetic attraction of the index magnet is stronger towards tooth 64 than tooth 58 and the index magnet thereby drives the index wheel 50 in the direction of the arrow B until the tooth 64 is centered over the index magnet as was the tooth 58 in FIGURE 2. The index wheel has thereupon been indexed one tooth position and contact to the coil has been established through the very movement that caused indexing.

Referring now to FIGURE 4, there is seen the return swing of the balance staff and index roller. With the index roller moving in this return direction, the jewel pin 16 will completely pass by the tooth held in equilibrium by the index magnet '56 as may be seen from FIG- URE 2 and a comparison of the path of movement of the jewel pin indicated at C and the equilibrium tooth '58. Referring back to FIGURE 4, the jewel pin 16 strikes the acute angle edge 62 of a tooth in the relative position of the tooth 64 in FIGURE 2 and moves that tooth to the broken line position shown at 68 in FIGURE 4.

The total movement of the index wheel 50 during this engagement with the jewel pin on back swing is indicated by the arrow D in FIGURE 4 and is less than the movement of the index wheel on engagement with the contact during forward swing as is indicated by the arrow E in FIGURE 2. The larger movement E in FIGURE 2 is suflicient to bring the tooth being moved into a position over the index magnet where the magnet draws the tooth forward. On the back swing however, the movement is insufiicient to cause the index magnet to advance the wheel and therefore when the jewel pin clears the tooth, the tooth merely returns to its position of rest over the magnet. As a result, the oscillation of the balance staff imparts a one-way rotary motion to the index wheel.

While the shape of the contact 18 in FIGURES 1 through 4 represents a preferred contact shape utilizing the diagonal edge 20, it is possible to use different shapes of contact members. Thus, referring to FIGURE 5 there is shown another embodiment of the invention wherein similar parts are provided with the same reference numerals. According to this embodiment of the invention the contact comprises a flat strip 70 adhesively secured to the jewel pin 16 in place of the diagonal shaped contact of FIGURES 1 through 4. It is believed apparent that the operation of this embodiment of the invention is identical to that previously described in connection with the embodiment shown in FIGURES 1 through 4.

As a result of the above-described action of the contact and index system of this invention it is possible to drive the index wheel of an electric watch from the oscillating motion of the balance staif while utilizing the same driving energy to provide electrical contact to a coil carried by the balance staff. The number of parts previously necessary to provide such contact is very substantially reduced thereby permitting the construction of a thinner electric watch movement. In addition to this, the adjustment of the older type spring contact is eliminated while at the same time the reliability of contact is improved.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. A contact-indexing device for an electric watch comprising an oscillating balance staff, a toothed index wheel adapted to be driven by said balance staff, contact-index means carried by said balance staff, said contact-index means engaging said index wheel as said balance staff oscillates to advance said index wheel in one direction and to establish periodic electric contact between said index wheel and said contact means, a permanent magnet mounted at one side of said index wheel and imparting an axial thrust thereto, an electrically conducting staff carrying said index wheel, and a contact member engaging one end of said staff to establish electrical contact therewith, said magnet thrusting said statf against said contact member to provide contact therewith as said index wheel rotates.

2. A contact-indexing device as set out in claim 1 wherein said index-wheel comprises a magnetic portion and a non-magnetic portion.

3. A contact-indexing device as set out in claim 1 wherein said contact-index means comprises an index roller mounted on said balance staif and a jewel pincer-- wheel adapted to 'be driven by said balance staff, a roller on said balance staff, an index and contact means mounted on said roller and including an electrically insulating cam member and an electrically conducting contact, said index and contact means engaging said index wheel as said balance staff oscillates to impart step by step advancement thereto in one direction, said contact electrically engaging said index wheel during at least a portion of the oscillation which causes said advancement, said cam engaging said index wheel during the reverse oscillation which causes no net advancement, a detentedrive means holding said index Wheel in pre-established rest positions and imparting drive thereto during each step by step advancement, said detent-drive means comprising a 6 permanent magnet imparting an axial thrust to said index wheel, a staff carrying said index wheel, and a contact member engaging one end of said staff, said magnet thrusting said staff against said contact member to provide contact therewith as said index wheel rotates.

References Cited in the file of this patent UNITED STATES PATENTS 750,492 Schmidt Jan. 26, 1904 1,752,446 Marti Apr. 1, 1930 1,964,857 Neumann July 3, 1934 2,195,311 Hurst Mar. 26, 1940 2,577,703 Fillinger Dec. 4, 1951