The Quest for Accuracy

 By Bruce Shawkey

Found this fun little article in a 1960s issue of Europa Star magazine:

The Bulova Accutron increased watch accuracy to about a minute a month. Wasn't this good enough? How accurate does a watch or clock need to be?

Here's another article that deals with this question:

Function The circuit of the motor Is without current when the motor is stopped. Therefore. it cannot sleet on Its own. as the transistor, which transmits the Impulses to the motor is dosed. The motor. thmefore, has to be slatted by means of a "start-ing lover" specially created for that purpose. to that the transistor can again transmit the neces-sary impulses. This lover Is built into the escapement and starts simultaneously the motor and the balance wheel. The motor turns with a speed that is determined by the battery voltage. i.e. at 1.5 Volt ankh 1,000 turns per minute. It turns continuously until No battery is flat. The pinion of the central axio of the motor is situated vertically in front of the escapement. 

As soon as the starting device has been actuated, a co-operation begins between the balance wheel. the lever leek. the *harshened wheel and the motor. However, it would be far too complicated to des-cribe NI: coApenition In a few sentences. It sulfides to know that with each full oscillation of the balance wheel the motor is temporarily coupled to the escapement, in order to resel the lever fork into its initial position, with the spiral spring armed and thus ready to transmit a new Impulse to the balance wheel. This coupling is done by the star-shaped wheel which works with the pinion of the motor. 

The axle of the star-shaped wheel surpasses the holding plate of the escapement and ends in a worm-gear, which operates the wheel of the seconds hand. Thus ihe seconds hand Is also moved forward by the fraction of a second when the lover is turned back to its original position by the star-shaped wheel. 

The periodic coupling of the star-shaped wheel to the pinion of the motor is controlled by the lever fork when it Is at the end of Its working stroke. i.e. at a moment when the ellipse el the balance wheel has already left the lever fork. 

    Thus the balance wheel is kept moving through periodical Impulses of the spiral spring mounted on the lever shall. Any other function takes place after those moving Impulses. Any variation or alteration of the transmission elements or the decrease of the battery tension do not influence the precision of the watch rate. 

In fack these elements are just reselling the lever fork into its Initial armed position and move the hands. This operation may be slowing down on account of the continuous discharging of the battery. however, the rata of the balance wheel Is not Influenced and neither the Indication of tho exact lime. 

This is for the first time that an electric clock movement has been developed. In which the balance wheel Is kept mowing through impulses of constant power, which results in the fact that this movement is independent from any distur. bailees.

Conclusion 

The Estop movement and the forms In which the Seclicon clock are presented constitute a very real advance. However. this is not all; new ma-nulacturing techniques have been developed so that the cost ol the finished clock is not excessive and within the range of a wide section of the Public. 

The Sicken clock thus nsc a definite need at the present day: It makes available to everyone a timekeeper of a new order of accuracy, in a pre-sentation that fits in with both classical and modern styles ol room furnishing.