PHILIPP HÖRZ, ULM, GERMANY, late 1890's
Two train with hour and half hour count wheel strike. Cast iron/steel post and strap frame. Graham deadbeat escapement with adjustable pallets. One second wooden rod pendulum. Harrison type type maintaining power. Movement is equipped with a one minute period Robert Robin , (Huygens endless chain style) gravity remontoire. 1 17.5"w x 18"h x 18"d.
Notice in the third photo the safety provision made at the top of the pendulum. In case of a failure of the suspension spring, the pendulum will not drop catastrophically, but be retained by the ring surrounding the suspension mount. See Horz 3 train, Hainz, and Schwalbach for other examples. In the first and second photo one can see the tight complexity of this clock. It has the same weight as its' larger three train model.
The first two photos show the larger (driving) weight of the two used in the endless chain remontoire system. The 'L' shaped brace holds a spring-loaded pad that can just be seen under the weight. As the weight descends it depresses the pad which is attached to a rod connected to a detent. When the detent is actuated the remontoire cycles, thus lifting the weight back to its' starting position about 1/2 inch above the pad. The cycle is driven from the main going barrel weight. This type of remontoire is sometimes found in fine spring-driven table clocks, typically French. It's use allowed the clock to have the portability that a spring afforded with the accuracy provided by the constant force of gravity, in addition to the other benefits of a remontoire. For a further discussion on remontoire see Wagner. The Robin style of remontoire was not popularly employed in tower clocks, perhaps because of the harsher environment that a tower clock is typically found. There is a greater possibility of the chains becoming fouled, or entangled from careless winding. While this remontoire is of French origin, to date I have only found this system used by a few German tower clock makers.
Click on pictures for more details and restoration shots.
1. The Robin remontoire was an invention of Robert Robin, France. In 1772 he presented a paper to the Academie Royale de Sciences on his remontoire for which he is best known. It is based upon the Christiaan Huygens endless rope system invented by Huygens in 1658 as means for maintaining power to a clock mechanism while it is being wound (maintaining power system). Robin's genius was to make this endless rope maintaining power system automatic through one of the wheels in the Huygens system being powered by the main going barrel and released periodically by a detent connected to the Huygens remontoire weight. This relatively simple, reliable system allowed a clock to have the portability of a spring-driven clock with the constant power of a weight driven clock. It also serves the same purpose as any other train remontoire of isolating the escapement from the inaccuracies found through the rest of the clock train, and in the case of a tower clock, the effects of weather on the exterior dial being transmitted backward to the escapement.