The present invention relates to a new and improved construction of transportation installation, and, more specifically relates to apparatus for transmitting control signals to transportation installations, especially in the form of elevators or the like.
In its more particular aspects the present invention relates to apparatus for transmitting control signals to elevators, wherein for the puspose of reducing the number of transmission lines the signals representative of the floor and cabin call as well as the cabin position are transmitted in coded form, there being provided memories in which there can be stored the coded floor and cabin call and the coded cabin position signals. Additionally, a comparator compares the signals representative of the floor and cabin calls with the cabin position and produces a respective control signal governing the direction of travel and stopping of the elevator cabin.
In order to save in transmission lines it is generally known in this particular field of technology to employ for relay-remote controls group selection circuits with diode matrixes. Thus, for instance, in the case of a diode matrix having ten inputs and five outputs, it is possible to transmit ten control commands which have been simultaneously infed to the inputs by means of five transmission lines connected with the outputs.
Now in U.S. Pat. No. 3,882,447 granted May 6, 1975 there is known to the art an apparatus wherein powering and controlling of the floor lamps and the lamps of the elevator cabin or car position display of an elevator system is accomplished by means of a diode matrix. The rows or lines of the matrix are correlated to the up service lamps and down service lamps and the cabin position lamps, whereas the columns of the matrix are correlated to the individual floors. The lamps are connected in series with the relevant diodes which bridge the cross-over or intersection points of the matrix. Each row and each column has a transistor switching circuit which can be switched by means of a control signal and by means of which there can be switched the lamps.
Although with this apparatus it is possible to save or wiring and switching circuits due to the employment of the diode matrix, nonetheless the prevailing equipment expenditure is still quite considerable in view of the relatively complicated transistor switching circuits, and therefore, cannot be tolerated for elevator controls which should be less expensive.
According to another state-of-the-art control apparatus as taught in the French Pat. No. 1,562,779 the floor and cabin call signals as well as the cabin position signal are transmitted in a coded form. For this purpose there are provided two diode matrixes. One of the diode matrixes is used to form the cabin call information, whereas the other is employed to form the floor and cabin position information. Binary techniques are used for coding. All information which is present in the form of coded words are transmitted over common lines or conductors and stored in memories or storages. Logical switching circuits prevent the simultaneous transmission of the information. Thus, the formation, transmission and storage of the cabin position information only is accomplished during travel of the elevator car or cabin, and the input of floor and cabin call signals is blocked. The formation, transmission and storage of the floor and cabin call signals is only possible during stoppage of the elevator cabin, and at the same time there is blocked the input of the cabin position. The information stored in the cabin and floor call memories are compared in a comparator with the information stored in the cabin position memories and the result is infed to a drive control.
With the previously discussed control apparatus there is realized a certain saving in the transmission lines or conductors, which, however, it still not adequate for elevator systems which should be of low cost. A further drawback particularly arises from the use of only one single diode matrix for the floor call and the cabin position. This requires, apart from additional lines or conductors, an appreciable expenditure in logic circuits for the mutual blocking of the input. Additionally, for the input of the cabin position there is required at the chute or shaft for each floor a switch, this resulting in an additional increased cost of the elevator system. A further drawback resides in the fact that with power failure it is not possible to ascertain the elevator cabin position, which, in turn, requires that there be accomplished a correction travel to the next floor of the building.
In Austrian Pat. No. 249,923, there is disclosed a control apparatus for elevators wherein the cabin position can be transmitted in a coded fashion without using a diode matrix. In this system there is mounted at the elevator cabin a four-place or four-position optical or magnetic scanning device which coacts with diaphragms mounted in the elevator chute or shaft. The diaphragms which are mounted at the height of the relevant floor are arranged, as concerns number and sequence, in accordance with the binary code used for coding purposes. So that there is not present any switching point differences there is provided for each floor an additional, shorter diaphragm which frees the evaluation of the remaining diaphragms. The resultant large number of diaphragms which are required for this system constitute an appreciable drawback of such control apparatus. A further shortcoming is that after power failure the cabin position no longer is known so that here also there must be accomplished a correction travel of the elevator to the next floor or storey.