US2642715A - Pendulum actuated electric clock - Google Patents

Description

June 23, 1953 L. ROBERT PENDULUH ACTUATED ELECTRIC CLOCK Filed Dec. 20, 1948 r x 0. 2.. Tm mm Mo N m W m x m W m 3 A m 1 W Patented June 23, 1953 UNITED STATES PATENT OFFICE PENDULUM AUTlJZ'iZEiJLE-GTBIC CLOCK ApplicationDecemb'er 20, 1948, Serial N'o. 66,'331 In France January 16,, 1948 1 Claim. 1

This invention relates to 'ele'ctricclocks Wherein the pendulum is driven by the action exerted by an emissive coil on a magnetized bar. ln such clocks it is essential to obtain the maximum isochronism of the oscillations.

Various devices have been hitherto proposed which provide means for applying a braking effeet at the end of the oscillation to improve the above-mentioned isochronis'm. For this purpose, three-pole magnetized bars have been utilized, having two poles of the same sign at the ends and a third pole of the opposite sign in the middle.

Magnets have also been utilized, which are driven by an energizing coil secured at the rest position of the pendulum.

Such arrangements are only 8fi'l01811t when the positive resistances of the clock mechanism are very low. It is therefore necessary to overcome the resistances and the losses of inertia.

To overcome the disadvantages outlined above the present invention provides an electric clock wherein the braking action is obtained by the combination of a central coil mounted on the clock stand and cooperating with a three-pole magnet having spaced-apartrecurvate, two poles of the same sign being positioned at the spacedapart ends of said magnet while the third pole of opposite sign is positioned centrally of said magnet. The mechanism of the clock according to the invention is much simplified and necessitates but a very small number of wheels.

The oscillating movement of the pendulum ensures the tooth by tooth rotational drive through the intermediary of a special pawl control member, of a first wheel carrying a stud adapted to actuate the minute wheel, which is, while the hour wheel journaled freely on the minute wheel shaft, is frictionally driven at regular intervals by this shaft when the hour wheel is released from engagement with a locking device.

Other characteristic features of the invention will become apparent from the following description with reference to the accompanying drawing, in which:

Fig. 1 is a front view of the clock mechanism partly broken away to show details of construction, and

Fig. 2 is a side view of same.

Fig. 3 shows the manner in which the clock journals are mounted.

Fig. 4 is an enlarged perspective view of the driving mechanism for the hour hand.

The mechanism is supported by two plates I and I. The pendulum oscillates about a spindle 2 journalled in the aforesaid plates and com- 2 prises a rod "3 weighted at its lower portion :by a' cou'nterweight of :conical shape, :formed from a plurality of washers .such as 5. This particular shape of counterweight reduces resistance during the oscillatory. movements.

The rod 3 'carries1under the counterweight a magnetized bar 6 having spaced-apart .recui'vate ends, as shown in Rig. 1., and having at -:'I,, 1" "two poles of same. sign and at l" a pole of opposite sign.

The distance separating the two ends I, I is equal to the length .of 'a coil '8 which has :its axis arranged horizontally and is secured to the clockcasing or base member in 3111051131011 corresponding to the rest -position of the pendulum. The pendulum :rod '3 is :causedto oscillate-by the periodic energization of the coil 8. Since the ends I, l areof the same polarity, which is :orpposite in sign to 'thepole 'I each will be driven out of the coil 8'upon its :energ-ization, i. :e. this action will occur when either of the poles I, l is in the coil 8, so that the oscillation of "the pendulum .is constantly energized.

The pendulum is arranged to drive :either directly or, in the case of a .large-isize clock,x by means of a fork .member, a pawl 8 mounted on an arm I0 secured to the spindle 2 of the pendulum. This pawl 9 drives a toothed wheel I I. To prevent each oscillation of the pendulum from causing the wheel II to be driven on more than one tooth, the pawl 9 is fast, by a common connection with a strap 35 which pivots about a shaft 36, with a hook-shaped cam member l2 guided by a fixed pin I3 secured on the plate I. Thus the engaging portion of the pawl 8 is lifted out of meshing engagement with the teeth when the wheel II has been rotated by a one-tooth interval. A lever I4, pivotally mounted about I5 carries a pin 31 which engages the teeth of the wheel II whereby the rotation of the wheel I I will raise lever I4 which will connect by means of contact element 38, on reaching its uppermost position, the terminal contacts of the wires I6, ll inserted in the circuit for energizing the coil 3. These wires may be concealed within the clock casing on their remaining path.

The wheel II is fast with a pin I8 meshing with the teeth of a wheel [9 so as to rotate the latter. A retaining pawl 20 is provided in order to limit the rotational movement of wheel I9.

The shaft 2 I, carrying the wheel I9, also carries an eccentric cam 22 and the minute hand 23. The hour hand 24 is fast with a sleeve 25 on 3 which a ratchet wheel 26 is secured. The sleeve 25 is loosely mounted on the shaft 2!.

A vertically arranged fork 28 is pivoted on another shaft 21; this fork has at the end of each prong thereof a pair of pins 29 adapted to mesh with the teeth of the ratchet wheel 26.

As shown in Fig. 4, an eccentric cam 22 mounted upon the shaft 2| is positioned for rotation between the prongs of a fork member 28. The fork member 28 carries pins 29 which are adapted alternately to engage the teeth of ratchet wheel 26 to hold it against rotation by frictional engagement with the shaft 2|. Rotation of the eccentric cam 22, which is effected by the rotation of shaft 2|, causes the fork member 28 to reciprocate laterally and to release, at regular.

intervals, one of the pins 29, thereby permitting the ratchet wheel 26 to rotate and then effects Ie engagement of the other pin 29 with the teeth of the ratchet wheel to hold the wheel against rotation until the next periodic release.

This will cause the hour hand 24 to rotate at regular intervals. With the arrangement described one of the gearings of the conventional clock mechanism may be dispensed with.

To reduce frictional losses between shafts and their journals, the latter are made of simple cylindrical members suchas shown at 30 in Fig. 3. These cylinders engage hollow sleeves screwthreaded externally so as to be screwed into the plates. A set-pin 3| is provided for acting as a counter-pin to the end journal pin of the shaft 39.

The clock casing is formed by two uprights of any suitable material such as wood, provided with grooves,- as at 32, for receiving both in the front and back faces of the mechanism, glass plates 33, 34 adapted to prevent dust or other foreign substances from penetrating into the mechanism. The front glass plate 33 acts as a dial. This plate. may be provided with the conventional marks either by engraving or other mechanical or chemical action applied to the glass surface, vor by adhesively secured signs of paper or other material.

7 It will be readily understood that the embodiment described hereinabove and illustrated in the accompanying drawing is merely given by way of example without any purpose of limitation as to shape, size, arrangement, material utilized, etc. Various modifications may be brought to the details of the apparatus without impairing or exceeding the scope of the invention.

What I claim is:

electric clock comprising a pendulum, electrically-energized means for oscillating said pendulum, a minute wheel fixedly mounted on a shaft, a first toothed wheel provided with a pin in driving engagement with the said minute wheel, a toothed hour wheel having circumferenti'ally disposed teeth and rotatabiy mounted upon said shaft and rotatable by frictional engagement with said shaft, a vertically disposed fork member having spaced-apart prongs pivotally mounted about a fixed point below the said shaft and carrying adjacent the ends of said prongs a pair of pins engageable between the teeth of said hour wheel, an eccentric cam member mounted on said shaft between the spaced-apart prongs and engageable with the sides of said prongs to cause a regular oscillating movement of said forked member upon rotation thereof, and a pawl control means actuated by said pendulum and actuating in turn in a tooth by tooth manner said first toothed wheel.

LEON ROBERT.

References lCited in the file of this patent UNITED STATES PATENTS Number Name Date 120,185 Davis Oct. 24, 1871 541,840 Diehl July 2, 1895 1,970,412 Bates Aug. 14, 1934 2,209,858 Steiert July 30, 1940 FOREIGN PATENTS Number 7 Country Date 19,818 Great Britain of 1914 571,105 France Jan. 26, 1924 479,376 France Dec. 24, 1915 677,304 France Dec. 9, 1929

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