An astronomical precision observatory wall regulator with a spring impulsed escapement, remontoire, electrical winding system, barometric and stratified temperature compensation. The case is nickel plated brass fitted with etched glass. Made by Sigmund

This is one of eight clocks manufactured in this very attractive case format. In my opinion, these 8 clocks are the are the most attractive of all the Riefler products. This example is considered by many to be the best of the eight because it is the most complete. This fine regulator is sold with its original Riefler instrument panel and slave clocks by Magenta. This wall mounted cabinet ( 33 inches tall, 28.5 inches wide and 8 inches deep) has a glass door where one can see the contents inside. This includes rheostats, voltmeter, ammeter for the regulation of the electrical current to the remontoire coils and for the transmission of time signals to chronographs, seconds sounders and slave clocks. A schematic wiring diagram signed by S. Riefler, installation instructions and original sales invoice are also included.

Case: This is a form that has stood the test of time. Today, many would still consider this 100 year case style to still be a progressive presentation. The timepiece is wall mounted to a backboard that is fitted with electrical components on the upper left side. The backboard of the clock case is rigidly mounted to this supporting board with four large screws. From this board the case is hinged on the right. The mahogany top and bottom, four nickel plated brass supports and three etched glass panels swing away from the backboard so as to provide access to the interior without disturbing the movement and pendulum. The panels are frosted in a decorative pattern. Clear surfaces allow one to view the timepiece. This case measures approximately 60 in. (152 cm.) high; 17¾ in. (45 cm.) wide; 9 in. (23 cm.) 

Dial: The diameter of the dial including the gilt bezel is 10.25 inches (26.25mm). The engraved and silvered brass dial features a conventional regulator layout. Minutes are positioned around the perimeter in a closed minute ring. The 5 minute divisions are labeled in Arabic style numerals. The minute hand originates from the center of the dial and as a result is the longest of the three hands on the dial. The seconds are displayed in the upper half of the dial. These are labeled in 10 second increments in Arabic numerals. The hour dial is located in the lower half of the dial. The hours are displayed in a 24 hour format. The outer hour ring has 0-11 in Roman style numerals and 12-23 are labeled in Arabic. It is signed DR. S. Riefler – Munchen / (Patent date Nos.) D.R.P. No. 50739 – D.R.P. No. 100870 / No. 341 – (and dated) 1913. A cut-out in the dial allows one to view the position of the remontoire weight and provides access to clean the electrical contact. The three hands are finely shaped from blued steel. Four steel screws mount this dial to the dial feet that are secured to the front plate of the movement.

Movement: This is a very high quality movement. Its design is respected the world over and became a benchmark in the quest for precision. The brass plates are 4mm thick. The brass is tempered and milled. Four substantial brass posts or pillars support the plates and are secured with steel screws. A heavy milled bracket, fastened to the backplate with screws, supports the two agate discs mounted to the top of the works. These form the bearing surfaces for the knife edge suspension. The anchor and the pendulum suspension are one rigid unit and this is designed to rock via hardened steel knife edges on top of the agate surfaces at a precisely determined axis. This directly relates to the same axis that he pendulum oscillates on. The provided impulse to the pendulum is done by flexing the suspension spring through the suspension block rather than the conventional crutch system. The escapement employs two co-axially mounted wheels that provide locking and impulse. The driving weight is re-cocked electrically by two coils that are situated on the left-hand side of the movement. All of the hardened steel arbors run in sapphire bearings and are set in screwed chatons. The pallets and contact breaker are also sapphires. The wheels are treated in a gilded finish and the steel parts are polished and chromed. A 4 volt battery powered electro magnet operates a remontoire which is mounted on the front plate just behind the dial. The remontoire weight (10g) is rewound every 20-40 seconds depending on the state of the battery charge. The works and dial are mounted on an iron bracket that is secured to the wall mount. Two large thumb screws fasten the movement via threaded holes in the lower movement posts to the bracket. The bracket also has adjustable screws in order to adjust the fit correctly.

Pendulum: Sigmund Riefler had an on going business where he made and sold pendulums to be used by other clockmakers. It is estimated that he made and sold 3,839 pendulums. His pendulums were state of the art and designed from the point of view of mathematics. This pendulum is the JSCH model and features barometric compensation. It was designed to function in free air, taking into consideration variables such as temperature and changes in barometric pressure. When the temperature variable is accounted for, the variations of temperature are considered at different levels of the room. So the compensating tubes are positioned at a pre-determined position from the top of the rod. The regulation is preformed first from the large 40 toothed nut supporting the bob. One complete revolution alters the daily rate by 40 seconds. A change in position of one tooth reflects a change of one second a day. This wheel has a hinged locking lever which when engaged prevents accidental adjustments of this feature. All of these components are made of invar. In addition, a tray is fitted to the rod so one can place weights on it. This is also aid the regulation of the clock or to bring the pendulum into time. Two weights of 2 grams are provided. The addition of one wight will change the rate by 5 secs in 24 hours. Both of these are mounted on silk threads. The two levers that support the threads are adjustable and mounted to the back of the case. The bob is a distinctive shape. It is referred to as a double truncated cone. The designed proved to be very effective. The bob is engraved with the following, “RIEFLER / MUNCHEN / D.R.P. / 100870 / 1734.”

Barometric compensation: Barometric compensation is preformed by an aneroid barometer that is mounted on the pendulum rod. The aneroid tank is engraved with the number 75. On the top of the vacuum tank is a carefully calculated weight. This rises and falls in inverse proportion to the rise and fall of the barometric pressure.

This fine regulator was designed and guaranteed to be accurate to .03 – .06 seconds a day.


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