Digital motor speed control

Claim 2

Apparatus for controlling the speed of a motor which is driven by pulse signals comprising first pulse-generating means connected to said motor for generating first pulses wherein the time between successive pulses is a function of the speed of rotation of said motor, second pulse-generating means receiving said first pulses for initiating the generation of a second pulse having a variable duration of time and for terminating said second pulse if the time between successive first pulses is greater than a preselected minimum interval of time, third pulsegenerating means for generating third pulses wherein each third pulse has a time duration related to the time interval between the instant of termination of one of said second pulses associated with one of said first pulses and the instant of initiation of the next occurring first pulse, and means for transmitting said third pulses to said motor.

Claim 3

The apparatus of claim 1 wherein said second pulse-generating means comprises a first pulse generator including input means for receiving in parallel two different pulse signals, said first pulse generator generating a first timing pulse signal which starts at the time of receipt of at least one of said pulse signals and terminates a given fixed period of time after the termination of both of said two different pulse signals, a second pulse generator connected to said first pulse generator for generating a second timing pulse signal having a fixed duration of time and activated at a predetermined time after the termination of said first timing pulse, means for connecting said first pulse-generating means and said second pulse generator to the input means of said first pulse generator whereby the two different pulse signals received are said first pulses and said second timing pulse signals.

Claim 4

The apparatus of claim 2 further comprising means for preventing the activation of said second pulse generator whenever the time between the termination of one timing pulse and the start of the next timing pulse is less than said predetermined time.

Claim 5

The apparatus of claim 3 wherein said third pulse-generating means is connected to said first and second pulse generators so that each third pulse starts at the start of a second timing pulse signal and terminates at the end of the next occurring first timing pulse signal.

Claim 6

The apparatus of claim 1 wherein said second pulse-generating means comprises a first time delay means, said first time delay means having first and second inputs and an output and including means for generating a pulse signal which starts upon receipt of a pulse signal by at least one of said inputs and ends a first fixed period of time after the termination of pulse signals at both of said inputs, one of said inputs receiving said first pulses, a second time delay means having an input and an output and including means for generating a second pulse signal a second fixed period of time after receipt of a signal at its input, means for connecting the output of said first time delay means to the input of said second time delay means for transmitTing a signal to the latter at the end of each first pulse signal generated by the former, and means for connecting the output of said second time delay means to the other input of said first time delay means.

Claim 7

The apparatus of claim 5 wherein said means for connecting the output of said second time delay means to the other input of said first time delay means is means for generating a third pulse signal of predetermined time duration.

Claim 9

The apparatus of claim 1 further comprising means for applying a continuous signal to the motor until the latter reaches a given speed during the start up period.

Claim 10

The apparatus of claim 1 further comprising means for applying a braking signal to the motor until the latter slows down to a given speed during the stopping period.