In the course of the production or refurbishment of switch mechanisms, the forces generated by the switch mechanism must be definitively set and tested. One of the aims is that the forces generated by the switch mechanism do not go above or below certain upper and lower limits. For this purpose, opposing forces that correspond to the forces of the switch blade during later operation are applied to the switch mechanism acting as a test piece while it is performing actuating operations on the test rig.
The mechanical dimensions of the switch mechanisms differ very widely according to the area of use, manufacturer and development history. Externally, common to all switch mechanisms is the so-called actuating slider, which transfers the linear movement and force of the mechanism to the switch blade, and (optionally) so-called test sliders, which are likewise connected to the switch blade and make a mechanical indication of the position of the blade to the mechanism possible. For the testing, the switch mechanism is ideally fastened in the same way as it is later on the track (usually by way of a number of screw connections). On account of the different outer dimensions of the mechanisms, the two movable components are located at different positions in relation to the fastening points of the switch mechanism.
The document “PT 10K Multi: Variabler Prüftisch für Weichenstellantriebe” [PT 10K Multi: Variable test bench for switch actuating mechanisms], available on the Internet on Mar. 31, 2014 at http://www.probitron.de/fileadmin/pdf/datenblatt_multi.pdf, discloses a variable test bench for switch mechanisms that consists of a basic module and exchangeable test modules. The basic module has a hydraulic system as a force generator, a controller and also measuring and safety equipment. Available for different models of switch mechanisms are individual test modules, which according to the illustration respectively consist of a bench with rollers and position holders that are individually designed for the switch mechanism. The adaptation of the coupling point between the test piece and the test-rig force generator consequently takes place by mounting the test piece on a test module that is individually designed for the test piece.
A test slider mechanically indicates the actual position of the switch blade to the switch mechanism. For testing the test slider, it would have to be moved at the same time as the actuating slider. However, in this case the movement of the actuating slider and the test slider do not take place synchronously; the length of the displacement is also different. Therefore, the known art dispenses with complete testing of the switch mechanism including the test sliders, since the switch mechanism is tested without the test sliders fitted. The test sliders are only fitted after the test.