US328769A - Electric clock - Google Patents

Description

(No Model.)

P. R. FIELD.

ELECTRIC GLOGK.

Patented Oct. 20, 1885.

Witnesses.

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UNITED STATES PATENT QFFIQEO FRANK R. FIELD, OF GREENFIELD, MASSACHUSETTS.

ELECTRIC CLOCK.

SPECIFICATION forming part of Letters Patent No. 328,769, dated October 20, 1885.

Application filed June 1,1880.

T0 aZZ whom it may concern:

Be it known that I, FRANK R. FIELD, of Greenfield, county of Franklin, State of Massachusetts, have invented an Improvement in Electric Clocks, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention relates to an electric clock of that class in which a time-measuring pendulum controls in its vibrations the circuit of an electro-magnet, which in turn actuates an impelling device by which an impulse is given to the pendulum, and its oscillatory movement thus maintained for an indefinite period of time.

The impulse is herein shown as derived from the force of gravity, the impelling device consisting of a pivoted arm arranged to bear by its weight against the pendulum during a portion of its vibratory movement in one direction, the said arm being raised or restored to its normal position before the return movement of the pendulum by the armaturelever of an electromagnet. This magnet is shown as having two coils, one in a perma nently-closed circuit and the other in a circuit controlled by the pendulum, the coils being so wound or connected that the currents passing through both tend to neutralize one another, so that the magnet is energized with maximum effect when the circuit controlled by the pendulum is broken and the current flows only through the permanently-closed circuit.

The impelling device is supported or held in its highest position by a prop, which is disengaged from the impelling device when the latter is engaged by the pendulum-rod near the end of its vibration in one direction, thus leaving the impelling device supported by the pendulum-rod, so that its weight acts to impel the said rod during a portion of its vibration, after which the impelling device, which in this instance directly controls the magnet, changes the condition of the latter, causing the movement of the armature-lever, by which the impelling device is raised or restored to its normal position and the prop placed beneath it.

When the impelling device arrives at its SerinlNo.1(l7,261. (No model.)

normal position, and is engaged and held by the prop, it again reverses the condition of the electro-magnet, causing the return movement of the armature, and thus leaving the impelling device free to act on the pendulumrod as soon as the latter again disengages it from its prop.

The armature-lover ofthe magnet may also be employed to actuate hands which indicate the time measured by the pendulum in the usual manner, and the main or primary clock may also control any desired number of secondary clocks or dials having actuating mechanism for hands, which are thus moved in unison with those of the main or primary clock.

Figure 1 is an elevation of the mechanism of the main clock as seen looking from the rear, the circuit being indicated in diagram; Fig. 2, a side elevation of the clock mechanism; Figs. 3 and 4, details showing the parts in different positions, and Fig. 5 an elevation ofthe mechanism ofone ofthe secondary clocks as seen from the front, the circuit-connection between it and the main clock shown in Fig. 2 being indicated in diagram.

The pendulum-bob a and the rod a may be of any usual construction, preferably being provided with means for compensation for variations in temperature, so that its vibrations will be as nearly as possible isochronous, it being shown as supported on a flexible spring, (E, in the usual manner.

The impelling device comprises an arm, I), pivoted at b at or near the point about which the pendulum oscillates, and a connected supporting-arm, b which rests on a prop orsupport, 0, until the moment arrives for imparting an impulse to the pendulum, which is done at each alternate beat. The center of gravity of the impelling device Z: I) is at one side of its pivotal point b so that it tends to oscillate about the said point. The extremity of the arm If is provided with a small shoulder or notch, b, which receives the end of the prop c and retains the latter in engagement with the said arm, and the prop is itself pivoted at c, and provided witha weight, 0, at one side of its pivot, so that it tends to turn from beneath the arm I), as shown in Fig. 3,

when the said arm is raised so as to disengage the shoulder I) from the end of the prop.

The arm I) is provided with a projection or finger, b (best shown in Fig. 2,) extending across the path of movement of the pendulumrod a, so that the latter at the end of its oscillation toward the left, when viewed as in Figs. 1 and 3, engages said finger If, as shown in Fig. 3, turning the impelling device slightly on its pivot, and raising the arm I), and disengaging the shoulder 71" from the prop c, which then turns from beneath the arm, leaving the impelling device supported by the finger If, resting against the side of the pend ulum-rod, so that in the return movement of the pendulum-rod the weight of the impelling device is added to it and imparts an impulse sutficient to make up for the resistance from friction and other causes to the movement of the pendulum. This impulse is imparted to the pendulum in its movement from left to right, as shown in Fig. 3, and it is necessary, in order to make the impulse eflective, that the weight of the impelling device should be removed from the pendulunrrod before it makes its return mo vement.

The impelling device is thus removed from the pendulum-rod and restored to its normal position, resting on the prop, as shown in Fig. 1, by means of an electro-magnet, d, and its armature e, and armature-lever 0, provided with a prop-restoring projection or finger, 6

The magnet d is shown in this instance as having two coils, one in a permanently-closed circuit, 2 3, with the battery B, and the other in a circuit, 4 5 6, including the said battery, and also including the impelling device connected with the wire 6 and a contact-piece, 0 on the armature-lever connected with the wire 5.

The impelling device is provided with a pin or projection, I), which in the movement of the said impelling device with. the pendulum, which imparts its impulse thereto, comes in contact with the piece 6 thus closing the circuit 4 5 6, through the second coil of the magnet d, the two coils of which are so wound or connected in circuit that when the current thus passes through both its effect is neutralized on the electro-magnet, permitting the armature e to be retracted by the retractor e, and in this retractive movement the impelling device is restored to its normal position by the armature-lever bearing against the projection I), and at the same time the finger c ofthe armature-lever acts upon a spring or yielding finger, 0, connected with the prop c, and thus tends to turn the said prop to its normal position, (shown in Fig. 1,) so that the moment the arm rises above the end of the prop the latter will be thrown beneath it by the elastic force of the spring-finger c, which has been somewhat strained by the movement of the armaturedever. (See Fi 4.)

The movement of the prop in this direction is limited by a stop,

The movement of the armature-lever is very quick, and it thus throws theimpelling device so that the latter will move on by its momentum after the backward movement of the armature has been arrested by a stop, 0 provided for this purpose, and will thus break the circuit at b c of the second coil of the magnet d, leaving the current unopposed in the permanently-closed coil, which will thus energize the magnet with full effect, causing the latter to attract its armature c, and thus restoring the parts to the position shown in Fig. 1 during thereturn vibration of the pendulum from right to left, at the end of which vibration. the propelling device will again be engaged by the 11iendulum-rod and the operations repeated, as before described.

In order to indicate the time measured by the vibrations of the pendulum, the armature (I may be made to actuate suitable wheel-work or to turn the hands of the clock in any usual manner. As shown, in this instance the armature-lever c is provided with apawl, f, engaging the teeth of a ratchet-toothed wheel, f, which is thus caused to turn once in a minute, and its arborf may be provided with a pointer or hand,f, (see Fig. 2,) which will thus rotate once a minute, like the secondhand of a watch or clock, and which may be made by means of suitable speed-reducing wheel-work (not shown) to turn a minute and hour hand in the usual manner. The pawl f is provided with-an inclined portion or looking-cam, f", which is engaged by a stationary projection or pin, f, in. its movement, which turns the wheel f, said pin thus holding the pawl down against the wheel and preventing the latter from turning beyond the point to which it is positively moved by the pawl. The retaining-pawl f prevents backward rotation of the wheelf when the pawlf is moved to engage a new tooth on the wheel.

The main or primary clock shown in Figs. 1 to 4 may also be employed to actuate any number of secondary clocks placed at any desired points that can be connected in electric circuit with the main clock,which circuit will include a circuit-closer operated periodically by the said main clock.

The actuating mechanism for the hands of the secondary clock is shown in Fig. 5, and comprises an eleetro-magnet, we, included in the circuit 20 21 with the battery B, the said circuit also including the circuit-closer controlled by the main clock, which consists in this instance of a pair of springs, a, normally insulated from one another and projecting into the path of the pin a, connected with the wheel f or its arbor, so that once at each rotation of the said wheel the said pin rubs over the springs a, completing the circuit between them, and then immediately afterward breaking the said circuit. The armaturem and its armature-lever m in the secondary clock is thus caused to make a to-and-fro movement by the magnet m and retractor m once at each revolution of the wheel f or, in other words, once a minute-and the said armature-lever is provided with a pawl, 0, engaging a ratchettoothed wheel, f, having sixty teeth, and provided with a retaining-pawl, 1', which prevents backward rotation while the pawl 0 is moved back by the action of the retractor m to engage a new tooth on the ratchet. The pawl 0 is provided with an arm, 0, extending along the armature lever substantially at right angles to the movement of the pawl, and the said arm is engaged at the end of the movement of the armature produced by the attraction of the magnet by a stationary stop projection, 0 which limits the said movement, at the same time holding the pawl down between the teeth of the ratchet and positively locking the same so that it cannot move too far by its momentum. A stop, m limits the backward movement of the armature under the action of its retractor, so that the pawl cannot be moved back over more than one tooth of the ratchet at a time.

It is not essential that the magnet (Z of the main clock should be a differential magnet, as shown. It might contain a single coil the circuit of which would be governed by the circuit-closer b 6 controlled by the pendulum, either closing the circuit of the said magnet and energizing it when the members of the said circuit-closer come in contact or closing a shunt of the said magnet and thus demagnetizing it.

If the magnet were energized when the circuit was closed at 1) e its position with relation to the armature would have to be reversed, as the armature-lever would restore the inipelling device and its prop in its movement toward the magnet instead of away from the magnet, as shown.

I claim- 1. The combination of the pendulum with an impelling device, and an electromagnet and its armature, by which the impelling device is raised or restored to its normal position after an impulse has been imparted to the pendulum, and a positive mechanicallyoperating prop or support for the impelling device independent of the said armature, which prop retains the impelling device in its normal position ready to impart a new impulse independently of the movement of the armature after the impelling device has been raised, substantially as described.

2. The pendulum and impellin g device, con sisting of two rigidly connected pivoted arms combined with a movable prop, which normally engages one of the said arms, the other arm being engaged by the pendulum-rod near the end of its vibration in one direction, and the prop disengaged from the impellin g device by the movement of the latter produced by the pendulum, substantially as described.

3. The pendulum-impelling device and its prop, combined with an electro-magnet and its armature, and armature-lever, provided with an electric contact-piece, the impelling device having a co-operating contact-piece which, when it comes in contact with the armature-lever, changes the condition of the net, causing a movement ofthe armature-lever by which the impelling device is restored to its normal position, the prop placed beneath it, and the contact-pieces separated, substantially as described.

i. A pendulum-impelling device and its pivoted prop provided with a yielding finger, combined with an electro-magnet and its armature and armaturelever, the said impelling device and armature-lever having co-operating contact-pieces controlling the circuit of the magnet, and the armature-lever co-operating with the impelling device and yielding finger of the prop in the movement which takes place when the contact-pieces come together, the armaturelevcr operating to raise the impelling device and by the yielding finger to place the prop beneath it, substantially as described.

5. The pendulum-impelling device having a shouldered supporting-arm and an arm which is engaged by the. pendulum-rod, combined with a pivoted prop which engages the shouldered arm, and is weighted to fall out from engagement therewith when the said arm is raised by the action of the pendulum-rod, substantially as described.

6. In an electric clock, the pendulum and its impelling device, and electromagnet by which the latter is restored to its normal po sition after an impulse has been imparted to the'pendulum, combined with a pawl having an inclined projection and a co-operatinglocking projection, and a ratchet-wheel actuated by the said pawl and imparting movement to the hands of the clock, substantially as dedescribed.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FRANK R. FIELD.

Witnesses: J AMES S. GRINNELL, FREEMAN C. Gnrswom).

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