US1927895A - Electric clock - Google Patents

Description

Sept. 26, 1933. P, MacGAl-IAN 1,927,895

ELECTRIC CLOCK Filed Aug. 8, 1930 i Fig. 2 Z

i 9 g g-3131 3" 2 /4 g 35 7 40 6O /0 a I 5 INVENTOR Paul MacGahan.

' ATTORNEY Patented Sept. 26, 1933 ELECTRIC CLOCK Paul MacGahan, Orange, N. J., assignor to Westinghouse Electric & Manufacturing Company, a corporation of Pennsylvania Application August 8, 1930. Serial No. 473,847

4 Claims.

This invention relates broadly to a timing device driven by a synchronous motor, and has particular relation to a motor-driven clock mechanism in which an indicator is provided '5 whereby notice is given in the event of a tem porary failure of current to the motor.

In apparatus of the above described character, it is necessary, in the event of failure of current supplying the motor, that some means be provided to call attention to the fact that the clock has been stopped. This is especially important when, as is often the case, the current failure lasts for a relatively short space of time. Upon resumption of current, the clock will immediately start, and, if there is no indication that a stoppage has occurred, it will not be apparent that the clock reading is inaccurate.

The former practice for accomplishing the above-mentioned object was to provide an auxiliary indicatoror signal, on the dial of the clock, actuated by an independent mechanism. My invention utilizes a part of the necessary clock mechanism, namely, the second hand or pointer, as a stoppage indicator.

. An object of my invention is to provide a mechanism of; the above-mentioned character in which one of a plurality oftime-indicating members of a clock is utilized to indicate a failure of current to the clock motor.

Another-object of my invention is to provide means whereby movement of one of a plurality of normally moving indicating members is permanently arrested upon failure of current to the clock motor and means whereby movement of the a member may be re-established, upon reception of current flow through the motor, at the will of an operator.

These and other objects of my invention are more fully explained in the following description, taken in conjunction with the accompanying drawing, in which p c Figure 1 is a schematic View of a clock mechanism constructed in accordance with my invention, and i Fig. 2'is a schematic'view of a modification of the mechanism shown in Fig. 1.

Referring to Fig. 1, a source of current is indicated as comprising conductors 1 and 2. A synchronous motor 4,. provided with the usual pole pieces 5,, field winding 6 and a rotating armature'7, is connected to the conductors 1 and 2 through a flexible cable 3. A plurality of indicators or pointers 8, 9 and 10 cooperate with the numerals 11, arranged in an ordinary manner around the circumference of a clock dial 12.

The pointers 8, 9 and 10 are secured, respectively, to one end of a plurality of concentrically disposed actuating shafts 13, 14 and 15. The shafts 13 and 14 are connected, respectively, through the gear train 16, to the shaft 35 of the motor armature 7. The shaft 15 of the second hand 10 is connected, through a Worm gear 17 and worm 18, a pair of clutch members 19 and 20, shaft 21, gear wheel 22 and pinion 23, to the shaft 35 of the motor armature '7. The clutch 65 member 20 is splined or keyed to the shaft 21 in such manner that the clutch member 20 may move longitudinally with respect to the shaft 21.

A bell-crank lever 24 having, at one extremity, a shifting fork or yoke 25, adapted to cooperate with the collar of the clutch member 20, is provided, at its other extremity, with an armature 26. The bell-crank lever is journalled to a shaft or pin member 28. A spring member 29 is provided to normally bias the bell-crank lever 24 to the position shown in the drawing. Stop members 30 and 41 are provided to limit the arc of travel of the bell-crank lever 24.

A manually operable reset member 31, substantially of U-shape, is journalled on the shaft 33. A bearing member 32, at one end of the resetmember, is adapted to cooperate with the bell-crank lever 24 for a purpose to be hereinafter more fully explained. The other end of the reset member 31 is provided with a push button 36.

The operation of my mechanism is as follows:

To start the clock, the synchronous motor 4 is connected to the conductors land 2, whereupon current will flow through the coil 6, and the armature '7 will rotate the indicators or pointers 8 and 9 through the gear train 16. At the same moment, the operator will press downwardly upon the push button 36, thereby moving the bell-crank lever 24 in such manner that the armature 26 will be placed in close proximity to the pole pieces 5 of the motor 4 and will be under the influence of the leakage flux of the pole pieces. The clutch member 20, at the same time, will move longitudinally, along the shaft 21, into engagement with the clutch member 19. The second hand 10, therefore, will also be connected to the shaft of the motor armature 7.

In the event of any failure of current in the conductors 1 and 2, the field winding 6 and the pole pieces 5 of the motor 4 will be deenergized. The armature 26 of the bell-crank lever 24, under the influence of the spring 29, will be moved away from the pole pieces 5. At the same time, the clutch member 20 will be disengagedfrom the cooperating clutch member 19, and the connection between the shaft 15 of the second hand 10 and the shaft 35 of the motor armature 7 will be broken.

If, however, current flow is reestablished in the conductors 1 and 2, the synchronous motor 4 will immediately start, the indicators or pointers 8 and 9 will thus resume their travel around the clock dial 12, but the second hand 10 will remain motionless.

The reading of the indicators or pointers 8 and 9 will thus be inaccurate, since the time interval of the duration of current interruption has not been recorded. An observer, by glancing at the clock and finding the second hand 10 motionless, is notified that the current has been interrupted. He immediately places the pointers 8 and 9 in their correct positions and then presses on the push button 36, which action, as explained above, will reestablish travel of, the second hand 10.

Referring to the modification shown in Fig. 2, a second hand or pointer 10 is secured to one end of a shaft 15. The other end of the shaft 15 is rotatably mounted in one end of a lever 37. The lever 37 is journalled to a pin 38. Armature 26 is secured, by means of a pin 27, to the lever 37. A worm gear 1'7, adapted to cooperate with the worm 18, is fixedly secured to the shaft 15. A slot 39 is provided in the second-hand dial 40 to allow lateral movement of the shaft 15 and the second hand or pointer 10, for a purpose to be hereinafter explained.

The operation of the mechanism shown in Fig. 2 is as follows:

When it is desired to start the clock, the indicating members 8, 9 and 10 are placed in their respective positions. The motor 4 is then connected to conductors 1 and'2 through the cable 3. At the same moment, push button 32 is pressed downwardly by the operator. The reset member 31 thus moves the lever 3'7 and shaft 15 upwardly until movement of the lever 3'7 is arrested by the stop member 41. The armature member 26 is thus placed under the influence of the leakage fiux of pole pieces 5 of the motor 4. The worm gear 17 will engage the worm 18, and the shaft 15 and the second hand 10 will move upwardly in the slot 39 to occupy a position in the center of the second-hand dial 40. The armature 7 will then rotate the indicators or pointers 8, 9 and 10 through the gear train 16 and shafts 13, 14 and 15.

In the event of any failure of current in the conductors 1 and 2, the pole pieces 5-of the motor 4 will become deenergized, and the armature 26, lever 3'7 and shaft 15 will drop downwardly under the influence of gravity until further downward movement is arrested by the stop member 30.

If current is reestablished in the conductors 1 and 2, the motor 4 will immediately start, and actuation of the indicating members 8 and 9 will be immediately reestablished. Actuation of the indicating member 10 will not be reestablished because the worm gear 17 has been disengaged from worm 18.

The reading of the indicators 8 and 9 will be inaccurate because the time interval of the duration of current interruption has not been recorded. The observer is notified of this fact when he notices that the indicator 10 remains stationary. He will then immediately place the indicators 8 and 9 in their proper positions and restart the indicator 10, as explained above.

I do not wish to be restricted to the specific arrangements of parts as described and illustrated, as it is apparent that various modifications thereof will fall within the spirit and scope of my invention. I desire, therefore, that only such restrictions be imposed as are indicated in the appended claims.

I claim as my invention:

1. Time mechanism comprising a plurality of timed driven members, a common driving source therefor comprising an alternating-current motor capable of operating in synchronism with a source of timed electrical alternations, the mechanism being of a type in which said motor and said driven members will stop upon a substantial cessation of the alternating-current power-supply for said motor, characterized by electro-responsive means for automatically causing said motor to start upon an establishment of said power-supply, means for simultaneously automatically starting less than all of said driven members and operating the same in synchronism with said motor while causing the remainder of said driven members to remain still, separately controlled means for placing said remainder of the driven members in synchronous driven connection with said motor after a period of interruption of the power-supply, and electromagnetic means responsive to the substantial maintenance of said power-supply for thereafter maintaining said operation of said remainder of the driven members as long as the power-supply is substantially maintained.

2. Clock mechanism comprising a plurality of time-indicating, driven members adapted to operate at different speeds to indicate different subdivisions of time, one of said driven members being a seconds-indicating member, a common driving source therefor comprising an alternatingcurrent motor capable of operating in synchronism with a source of timed electrical alternations, the mechanism being of a type in which said motor and said driven members will stop upon a substantial cessation of the alternatingcurrent power-supply for said motor, characterized by electro-responsive means for automatically causing said motor to start upon an establishment of said power-supply, means for simultaneously automatically starting all of said driven its iio

members except said seconds-indicating member and operating the same in synchronism with said motor while causing the seconds-indicating member to remain still, separately controlled means for placing said seconds-indicating member in synchronous driven connection with said motor after a period of interruption of the power-supply, and electromagnetic means responsive to the substantial maintenance of said power-supply for thereafter maintaining said operation of said seconds-indicating member as long as the powersupply is substantially maintained.

3. Time mechanism comprising a plurality of timed driven members, a common driving source therefor comprising an altemating-current motor capable of operating in synchronism with a source of timed electrical alternations, the mechanism being of a type in which said motor and said driven members will stop upon a substantial cessation of the alternating-current powersupply for said motor, characterized by electroresponsive means for automatically causing said motor to start upon an establishment of said power-supply, means for simultaneously automatically starting less than all of said driven members and operating the same in synchronism with said motor while causing the remainder of said driven members to remain still, separately controlled means for placing said remainder of the driven members in synchronous driven connection with said motor after a period of interruption of the power-supply, and electromagnetic means responsive to the electromagnetic flux produced in said motor for thereafter maintaining said operation of said remainder of the driven members as long as the power-supply is substantially maintained.

4. Clock mechanism comprising a plurality of time-indicating, driven members adapted to operate at different speeds to indicate different subdivisions of time, one of said driven members being a seconds-indicating member, a common driving source therefor comprising an alternating-current motor capable of operating in synchronism with a source of timed electrical alternations, the mechanism being of a type in which said motor and said driven members will stop upon a substantial cessation of the alternatingcurrent power-supply for said motor, characterized by electro-responsive means for automatically causing said motor to start upon an establishment of said power-supply, means for simultaneously automatically starting all of said driven members except said seconds-indicating member and operating the same in synchronism with said motor while causing the seconds-indicating member to remain still, separately controlled means for placing said seconds-indicating member in synchronous driven connection with said motor after a period of interruption of the power-supply, and electromagnetic means responsive to the electromagnetic flux produced in said motor for thereafter maintaining said operation of said seconds-indicating member as long as the powersupply is substantially maintained.

PAUL MACGAHAN.

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