Jewel lock
The Jüdel lock is a mechanism added to the switch setting device of rail switches , with which the positions of the two switch blades are secured. Its name goes back to the industrialist Max Jüdel , who, in addition to signal boxes , also produced switches from the end of the 19th century and brought this type of switch locks onto the market. Until recently, the Jüdel lock was the main switch lock used in Switzerland.
function
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The manual or motor drive for the switch adjustment cannot secure the positions of the switch blades produced with it without an appropriate device. Restoring forces that arise on the tongues during pulling operation can easily turn back the hand lever or the drive motor. In the spot of manual switches placed on horizontal pivoting lever has a weight attached (see left figure), that the tongues -positively fixed in their position. With motorized switches, the tongues are i. d. R. firmly held in a form-fitting manner. The corresponding lock can be attached close to the motor ("inner switch lock") or individually on each of the two tongues ("outer switch lock").
The Jüdel lock is a form fit between the tongues with half an adjusting rod each acting on one tongue: the inner end of the half rod leading to the adjacent tongue is brought behind a stop attached to the tongue threshold .
A lever (red) is pivoted horizontally with the rod coming from the adjustment drive (blue in the figure on the right). At its free end, two short levers, also horizontally pivoting, are coaxially attached (each marked with two small dots in green and magenta), which move the half-bars (also green and magenta) leading to the tongues from the other end. The main lever, a short lever, a half-rod, a tongue, and the turnout frame together form a five-membered transmission chain with five rotary joints that do not initially positively , d. H. has too much freedom of movement . The inevitability is created by restricting the freedom of rotation at the joint between the short lever and the half rod. There is a cam (marked with a colored circle) on the half-rod, which strikes the short lever when the rod wants to swing outwards. Your freedom of movement in the opposite direction is restricted as it hits the stop block fixed on the tongue sill (upper edges of the active surfaces marked in yellow). While the tongue is moved to rest against the outer rail, the inner end of the half-bar (green) slides on the transverse surface of this block up to its corner. Then the inner end of the half bar (green) goes "around the corner" and takes its end position in front of the block surface that is parallel to the tongue and serves as a stop.
The short lever and the half bar (magenta) to the other tongue are in the extended position. The cam of the half rod is at the stop of the short lever. The “knee joint” between them cannot fold through. In the opposite direction, the inner end of the half rod rests against the block.