US2997839A

US2997839A - Indexing and contact mechanism

Info

Publication number: US2997839A
Application number: US748961A
Authority: US
Inventors: Fritsch Daniel
Original assignee: Hamilton Watch Co
Current assignee: Hamilton Watch Co
Priority date: 1958-07-16
Filing date: 1958-07-16
Publication date: 1961-08-29
Anticipated expiration: 1978-08-29

Description

1961 D. FRITSCH 2,997,839

INDEXING AND CONTACT MECHANISM Filed July 16, 1958 28 FIG. I 26 FIG. 2

l6 FIG 4 4 l4 55 m 54 FIG. 3

FG' 5 INVENTOR 58 DANIEL FRITSCH so ATTORNEYS United States Patent'O 2,997,839 INDEXING AND CONTACT MECHANISM Daniel Fritsch, Lancaster, Pa., assignor to Hamilton Watch Company, Lancaster, Pa., a corporation of Pennsylvania Filed July 16, 1958, Ser. No. 748,961 Claims. (Cl. 58-28) This invention relates to the indexing mechanism for electric timepieces and more particularly relates to an improved mechanism of this type which combines the function of an index wheel pawl with that of a contact making arm.

In electric timepieces having oscillating balances, it is necessary to provide an indexing wheel which receives the power from the oscillating balance wheel and transforms the oscillating movement of the balance wheel into rotary motion in one direction. The index Wheel must therefore be provided with something for negating the oscillating motion of the balance wheel in one direction and for utilizing the motion of the balance wheel in the other direction to advance the indexing wheel in a step by step relation. In addition to this the timepiece also must contain a periodic switching mechanism for properly energizing the drive arrangement and this mechanism is most often actuated by the balance staff.

The present invention concerns itself with this indexing-contact problem and provides an improved solution to both aspects of the problem through a unique combined mechanism which accomplishes both functions.

It is accordingly a primary object of the present invention to provide an improved mechanism for simultaneously providing one way rotation of an index Wheel and periodic energization of the electromagnetic drive of an electric timepiece.

It is another object of the present invention to combine in an improved manner the mechanical means for changing the oscillating motion of the balance wheel into unidirectional rotary motion of an index wheel with a contact making arm.

It is a further object of the invention to provide a contact making arm formed of spring material which under the influence of a wheel turning in one direction will have a lateral motion while under the influence of the wheel when turning in the other direction will have a longitudinal motion.

It is a further object of the present invention to provide an indexing wheel which receiving impulses from the oscillating motion of the balance wheel transforms those impulses by reason of the tooth shape of the wheel and a spring pressed pawl into rotary motion in one direction, while at the same time making the contact which energizes the oscillating movement of the balance wheel.

These and further objects and advantages of the invention will become more apparent on reference to the attached specification and claims and appended drawing wherein:

FIGURE 1 is a partial section through a timepiece movement showing only those parts essential to illustrate the invention and with the wheel in the position of starting the indexing motion;

FIGURE 2 is a similar view shown at the end of the indexing motion;

FIGURE 3 is a similar view showing the wheel at the end of the return motion of the balance wheel;

FIGURE 4 is a partial horizontal section through a timepiece movement showing another embodiment of a device constructed according to the invention; and

FIGURE 5 is a further partial horizontal section showing still another embodiment of a device constructed according to the invention.

FIGURE 1 shows a balance stafi 8 supporting a roller Patented Aug. 29, 1961 table 10 which in turn carries an indexing pin 12. This stafl 8 carries the oscillating balance wheel and in turn brings the indexing pin 12 into engagement with the teeth 14 of the indexing wheel 16 when moving in either direction. The index wheel 16 carres a pinion, not shown, on the shaft 18 which in turn is connected to a train of gears to operate the hands of the watch. Only the essential parts of the invention are shown in this drawing, the entire timepiece being described in applicaton Seral No. 409,934, filed February 12, 1954, now Patent No. 2,888,797.

The indexing wheel teeth are formed with one radial side 20 and a side 22 at an acute angle to the radial side. The formation of the teeth provides for a lesser movement of the indexing wheel 16 in one direction than in the other when impulsed by the pin 12.

Connected to the electric circuit of the watch is a contact cylinder 24 connected to a Wire 26 carried on the contact post 28, the contact post wire and cylinder being the subject of a separate copending application. The cylinder 24 receives contact from a contact point 30 carried on an elongated spring arm 32.

The spring arm 32 shown in FIGURES l-3 is formed with three

right angle bends

34, 36 and 38 and terminates in a short section 40 which is spot welded to the post 42, which is an integral part of a bridge (not shown). Secured to the spring arm 32 is a D-shaped jewel 44 engaging the teeth 14 of the index wheel 16. FIGURE 1 shows the positions of the various elements at the start of the index motion.

Referring to FIGURE 2 it will be seen that the indexing pin 12 has moved to the end of its indexing stroke and is about to leave the tooth 14. The movement of the indexing wheel causes the jewel 44 to ride to the apex of the tooth 14 and this moves the spring arm 32 so that contact is made between the contact 30 and the cylinder 24. Continued movement of the indexing wheel 16 through inertia brings the D-shaped jewel 44 into position between two consecutive teeth of the indexing wheel. During this operation the spring 32 flexes approximately from the bend 34 so as to move the contact through an arc of which the point 34 is the center.

FIGURE 3 shows the staff 8 moving in the reverse direction and bringing the pin 12 into engagement with the leading side 22 of the teeth 14 to move the index wheel 16 in a direction opposite to that above described. This movement brings the D-shaped jewel 44 into contact with the radial side of the teeth 14 and moves the spring lever 32 longitudinally so as to cause the lever to flex about the angle 38. This motion does not move the contact 30 into engagement with the cylinder 24. At the end of this fiexure about bend 38 the jewel 44, which is still in engagement with the teeth 14, returns the index wheel to the position shown in FIGURE 1, so that the total movement of the indexing wheel 16 constitutes an advance of one tooth in the direction of the arrows shown in FIGURES 1 and 2. The movement of the indexing wheel in an opposite direction as shown in FIG- URE 3 is counteracted by the return movement caused by the spring 32 returning to normal position.

The use of the contact arm as a spring pawl for the indexing wheel combines the two functions in a relatively inexpensive part, easy to assemble and rugged and reliable in action.

While the embodiment of the invention shown in FIG- URES 1-3 utilizes three bends in the spring arm adjacent its point of attachment the invention is not limited to this type of construction. Thus referring to FIGURE 4 there is seen an arrangement wherein the spring arm 46 is provided with only two

bends

48 and 50. In this embodiment the spring arm is Welded to the post 42 at 52 and extends past the post at 54. This extension combines with the cross portion 56 to provide all of the. resilient action necessary to effect a proper action between the jewel carried by the arm and the index wheel. (Not shown.)

Referring to FIGURE 5 there is shown still another embodiment of the invention wherein a spring arm 58 is provided with a loop 60 having its end 62 attached to the post 64.

In. all embodiments of the invention the portion of the spring arm carrying the jewel is free to move in two directions substantially at right angles to one another.

.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 embaced therein.

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

a 1. In an electric timepiece having an oscillating balance wheel and staff, an indexing and contacting mechanism comprising, a pin carried by said staff, a toothed wheel indexed by said pin, a first contact, an arm extending past said latter wheel and carrying cam means engaging said teeth, a second contact carried by said arm and movable in a first direction substantially perpendicular to the longitudinal axis of saidrarm into ene gear-nee:-

gagement. with said' first contact, post means, said arm being attached at its end to said post means and being looped adjacent said post means so that movement of said toothed wheel in one direction moves said second contact in said first direction into engagement with said first contact, and movement of said toothed wheel in the opposite direction moves said second contact in a second direction substantially parallel to the longitudinal axis of said arm whereby said contacts do not engage one another.

2. An indexing and contact mechanism as set out in claim 1 wherein said arm extends about said post at least 270.

3. An indexing and contact mechanism as set out in claim 1 wherein said arm extends about said post ap proximately 360.

4. An indexing and contact mechanism as set out in claim 1 wherein said post means lies within said loop.

5. An indexing and contact mechanism as set out in claim 4 wherein the end of said loop is attached to one side of said post means and another side of said post means is spaced from said loop.

References Cited in the file of this patent UNITED STATES PATENTS 2,521,887. Wihanto Sept. 12, 1950 2,626,500 Westlake Jan. 27, 1953 FOREIGN PATENTS 370,956 Great Britain Apr. 8, 1932