System of automatically controlling distance in linear movement

DETAILED DESCRIPTION Accordingly, the primary object of the present invention is to provide a system of controlling that movable position of all the movable members which can be converted into linear movement between a first member and a second member to the position preset by a user through a mechanically contactless intermediary in which an ultrasonic pulse narrow in directivity and high in S/N ratio is used, wherein said first member and said second member are placed in a relatively variable relation in respect of distance between each other on a straight line.
In keeping with the principles of the present invention, the objects are accomplished by a unique system of controlling mechanically connected movable members (not shown) to a desired position so as to permit the movement of the position of the movable members in a specified relation with respect to the distance L between a transmitter T and a receiver R, said system comprising disposing said transmitter and said receiver between two members TO and RO, said transmitter being adapted to emit a narrow directional ultrasonic pulse, said receiver being adapted to receive and convert the pulse into an electrical signal, said members TO and RO interlocking mechanically with the movable members (not shown) which it is desired to control to a desired position and which are placed in a relatively variable relation with each other in respect of distance on a straight line between the members, deciding the distance L between the transmitter T and the receiver R with the time (hereinafter referred to as "propagation time") required for the distance between the transmitter T and the receiver R to have atained the desired distance on the basis of the propagation time required for the ultrasonic pulse generated from the transmitter T to be received by the receiver R installed in an opposed relation with respect to the transmitter T on a straight line, generating a suitable control signal, and controlling the distance L between the transmitter T and the receiver R to the desired distance