Switching techniques and devices

Claim 2

A switching device comprising a switch having an input terminal and an output terminal, said switch being operative between a first condition wherein a circuit is completed between the input terminal and the output terminal and a second condition wherein no circuit is completed between the terminals, and control means for operating said switch between said first and second conditions including means operative to rapidly and repetitively operate the switch between said first and second conditions with said switch initially remaining in one condition longer than the other and then progressively less in the one condition and longer in the other condition until the switch remains in the other condition substantially continuously.

Claim 3

The device of claim 1 including a summing circuit operative to produce an output signal which is a combination of the signals applied to the summing circuit, a first signal source connected to said summing circuit, a second signal source connected to the input of said switch and means connecting the output of said switch to said summing circuit whereby the signal generated by the second signal source can gradually be added to or removed from the signal appearing at the output of the summing circuit through the operation of said control means to operate said switch from being predominantly in one condition to being predominantly in the other condition.

Claim 4

The device of claim 1 wherein said control means comprises a first function generator operative to generate a repetitive signal, a second function generator operative to generate a second signal having a time constant which exceeds the period of oscillation of said first signal, and a comparator for comparing the instantaneous values of the signals generated by said function generators and having a first output when the instantaneous value of a first one of said signals exceeds the instantaneous value of the other and having a second output when the instantaneous value of the other signal exceeds that of said one signal, said switch being operative to one condition in response to the first output of said comparator and operative to said other condition in response to said second output.

Claim 5

The device of claim 3 wherein a signal generated by said first function generator is substantially a sawtooth signal wherein the signals generated by the second function generator is substantially a ramp function, the minimum value of said ramp function being less than the minimum value of said sawtooth function while the maximum value of the ramp function exceeds that of said sawtooth function whereby the output of the comparator and therefore the condition of the switch will remain constant except while said ramp function generator is transitioning between its peak values.

Claim 6

The device of claim 1 including a second switch which Is operative between a first condition wherein a circuit is completed between an input terminal and an output terminal and a second condition wherein no circuit is completed between the terminals, and wherein the control means includes coupling means operative to operate said second switch between said first and second conditions in opposition to the operation of said first switch between said first and second conditions whereby as said first switch is operated from being predominantly in said one condition to being predominantly in the other condition, said second switch is operated from being predominantly in said other condition to being predominantly in said one condition.

Claim 7

The device of claim 5 wherein said control means comprises a first function generator operative to generate the repetitive waveform, a second function generator operative to generate a second waveform having a time constant which exceeds the period of oscillation of said first waveform, and a comparator for comparing the instantaneous values of the first and second waveforms and having a first output when the instantaneous value of one waveform exceeds that of said other waveform and having a second output when the instantaneous value of said other waveform exceeds that of said one waveform, said first switch being operative to said first condition in response to one output of said comparator and being operative to said second condition in response to the other output of said comparator while said coupling means operates said second switch to said second condition in response to said one output of said comparator and operates it to said first condition in response to the other output of said comparator.

Claim 8

The device of claim 6 adapted for use in a control system wherein the second waveform is essentially a ramp function with a minimum value which is less than the minimum value of said repetitive waveform and a maximum value which exceeds the maximum value of the repetitive waveform and including a first control signal source connected to the input terminal of said first switch, a second control signal source connected to the input terminal of said second switch, and a summing circuit connected to the outputs of said switches whereby the control signal appearing at the output of the summing circuit is one control signal or the other while the ramp function is at its maximum or minimum value and is progressively switched from one control signal to the other as the ramp function transitions from one peak value to the other.

Claim 9

The combination of claim 7 including a third switch operative between a first condition wherein a circuit is completed between an input terminal and an output terminal and a second condition wherein no circuit is completed between the terminals, a third control signal source connected to the input of said third switch the output of said third switch being connected to the summing circuit, an additional second function generator operative to generate a waveform having a time constant which exceeds the period of oscillation of said first waveform, an additional comparator connected to the first function generator and the additional second function generator and having a first output when the value of one of these waveforms exceeds that of the other and having a second output when the value of the other waveform exceeds that of said one waveform, the condition of said second and third switches being responsive to the output of said additional comparator, additional coupling means for operating said second and third switches in opposition to each other in response to the output of said additional comparator and actuating means operative to selectively actuate a selected second function generator to initiate a switching from one control signal to another.

Claim 10

The combination of claim 8 including gates between the comparators and the respective switches to which they are connected, said actuating means also including means for actuating said gates to control the response of said sWitches to the outputs of said comparators whereby the response of the individual switches is controlled by a selected comparator.

Claim 11

The combination of claim 7 adapted for use in an elevator system comprising a structure giving it to at least two landings, a car mounted for movement relative to the structure to serve the landings, and regulating means for regulating the speed of the car in response to the speed control signal appearing at the output of the summing circuit, said first control signal source generating a course speed control signal, while said second control signal source generates a fine speed control signal, and actuating means responsive to the approach of a car to a landing at which it is to stop to actuate said second function generator to initiate switching from said course speed control signal to said fine speed control signal.

Claim 12

The combination of claim 10 wherein the course speed control signal is a time dependent signal and the fine control signal is a function of the distance to the floor at which the car is to stop.

Claim 15

The method of claim 12 adapted for switching between a first signal source controlled by said first switch and a second signal source controlled by a second switch similar to said first switch including the additional step of operating said second switch between its open circuit condition and its closed circuit condition in opposition to said first switch.

Claim 18

The method of claim 14 adapted for switching between a plurality of signal sources controlled by switches similar to said switch including the steps of generating a transition waveform for each transfer between signal sources desired, selecting the pair of signal sources between which the transfer is to be made, operating a first switch controlling a first one of the selected signal sources to said first condition when the instantaneous value of the associated transition waveform exceeds that of said repetitive waveform, operating said first switch to said second condition when the instantaneous value of the associated transition waveform iS less than that of the repetitive waveform and operating a second switch controlling the second one of the selected signal sources between its first and second conditions in opposition to said first switch.