Riefler -Borrill Precision Regulator Clock (MP 166)

The Riefler Clock

 The Riefler clock was first used in 1890 and quickly established itself in most the world's observatories as an accurate regulator until the advent of the quartz and atomic clocks.  It takes its place alongside the LeRoy and Shortt Clocks as the most accurate electro-mechanical devices invented and able to detect shifts in gravity caused by local tides and changes in the earth's precession.  It established a new standard in timekeeping by doing away with most of the pendulum's constraints and instead rocked the pendulum spring itself.  This was possible using a pendulum bearer with knife edges and a specially constructed escapement wheel and pallets.    The prototype clock pendulum swung in an airtight chamber which was almost a vacuum at a strictly controlled temperature and because it could not be rewound by hand, an electro-mechanical gravity lever was reset according to the Synchronome method.  The result was a very even power distribution to the escape wheel.   

The Meccano Riefler incorporates most of these features.  The pendulum rests on a bearer which is supported on knife edges and the escapement is highly accurate and uses the 30 tooth ratchet wheel.  The weighted lever is electrically reset using elekrikit parts, and there is a maintaining power device and pivot bearings to ensure even power distribution to the escape wheel.   The mechanism is housed in an attractive Meccano and glass case, and stands on a wooden plinth.

The clock is named after Stuart Borrill of Skegness who made the precision escapement wheels and pallets.


Clock drawings showing the anchor, pallets and escape wheels,  the knife edges and the pendulum suspension spring

Anchor, escape wheels and pallets

The Meccano Riefler Regulator Clock

Escape Wheels and Pallets


Pendulum carrier and one of the two knife edges