SU714338A1 - Device for intermittent driving of cine film in motion-picture camera - Google Patents

Description

The invention relates to film technology and can find application in film-making and film-projection devices, as well as in slide projectors and search engines, which require discrete movement of film by one frame with the possibility of simple pitch adjustment.

Known devices for intermittently pulling film, comprising a stepper motor mounted on a shaft

J of a jump drum and associated with a control circuit [1].

'The closest Wo technical essence to the proposed one is a device that has a device for centering the frame and its exact installation. The hopping drum in this "device is driven by a servomotor controlled automatically by a pulse circuit containing a trigger, a stop signal generator, a power amplifier, which is switched on * by means of control pulses generated by the photosensor of synchronous signals. The disk of the photosensor of synchronous signals is located on the "shaft of an electric motor rotating at a constant speed and setting in motion the pulling and holding gear drums of the Tape drive mechanism [2J.

However, this mechanism is very complicated, since S consists of a pulse control circuit having a large number of adjustable elements, and a servo system that contains a complex position photosensor in the feedback circuit and does not disconnect the supply voltage from the servomotor in the ₁₀ frame-standing mode. Changing the ' ^, ''Conditions of stretching the film (naira * i1mer, the formation of soot in the film channel, changing the pressing force, thickening of the grease in bearings, etc.) makes it necessary to adjust the control circuit of the servomotor.

The purpose of the invention is to simplify the design, and increase the reliability.

This is achieved by the fact that in the proposed

2F device, a forming amplifier, a coincidence element, and a pulse generator, the output of which is connected to the input of the forming amplifier connected to an electric motor, and to the

wow '' Entrance ^: ' _{t of the} element I match; the second input of the input is connected to the input of the power amplifier. The output of the threshold element is connected to the input of the stop signal generator, and the electric motor and servomotor are made on piezoceramic vibrators. _;

In FIG. 1 shows a functional diagram of a device for intermittent protyafig. 2 ^ diagrams of his work. ..... -

The device includes a film 1, a pulling drum 2, a retaining drum 3, a rotor of the 4th spinning piezoceramic vibrator 5, constituting an electric motor, a photosensor 6 of synchronous signals, a trigger 7, a stop signal generator 8, a power amplifier 9, a jump drum 10, a rotor 11 and a piezoceramic vibrator 12 constituting a '^ ^ Ш ШЖЖйтелнн,,,, a position feedback photosensor 13. the threshold element 14, the forming amplifier 15, the pulse generator 16 and the coincidence element 17.

In FIG. 2> the following diag. frames: control pulse 18 at the output of the photosensor 6 synchronous signals, voltage 19 at the output of the trigger.?, pulses 20 at the output of the generator 16, pulses 21 at: The output of the matching element 17, voltage 22 at the output of the power amplifier 9, change of rotor speed 23 11 servomotors, voltage 24 at the output of the photosensor 13 feedback • 'W'WRjikeHHjQ' and the response level 'of the threshold element. 14, voltage 25 at the output of the threshold element 14, pulse 26 at the output of the stop signal generator 8, ···. ··· '. ·;

The device works as follows. ' ^: When 'turning on the supply voltage, the generator 16 generates a sequence of pulses 20, which are formed'; an amplifier 15 in the excitation voltage '; piezoceramic vibrator 5, which 'drives the rotor 4 of the electric motor in rotation. constant speed communication. In this case, the photo of the sensor for 6 synchronous signals is issued by a clock pulse 18, which transfers the trigger <'' ger 7 to a stable state, in which 2 4 voltage 19 from the output of the trigger 7 is supplied. To the second input of the coincidence element 17, to the first input ~ 20 pulses from the generator 16. On the output element 17 matches for all the time specified by voltage 19 of the trigger 7, appears - ^; pulse ray 21, which after the transformation; In the amplifier 9, it enters in the form of a cosine - sinusoidal voltage 22 to the piezoceramic vibrator 12 of the servomotor. Piezoceramic vibration time. The rotor 12 in the mode of resonant mechanical vibrations causes the variation of the rotation speed 23 of the rotor 11 ser1338- / 4 of the motor from zero to maximum. This movement is transmitted to the jump bar: ban 10, which provides pulling, film 1, and to the position sensor feedback sensor 13. Simultaneously with stretching the film I, the voltage 24 at the output of the GB photosensor decreases to a certain level at which threshold element 14 is triggered. In this case, the voltage 25 at its output decreases abruptly. When the film 1 ^{ιβ is drawn} to a predetermined pitch of the frame, a voltage 24 appears at the output of the photosensor 13, at a certain level of which the 'threshold element 14 is triggered. A positive voltage drop 25 at the output of the threshold j ⁴ element 14 starts the stop signal generator 8, the output pulse 26 of which translates trigger 7 to another steady state. As a result, the voltage 19 is removed from the second output of the coincidence element 17 and there are no pulses 21 at its output, and the voltage 22 of the supply of the piezoceramic vibrator 12 of the servomotor is also removed. The damping mechanical vibrations of the vibrator 12 smoothly reduce the rotational speed of the rotor 11 of the servomotor to zero, ₅ and the mechanical pressure of the vibrator 12 to this rotor 11 provides a rigid fixation of its position.

This ends the stretching of the film 1 For one frame, the control system ^{10 is} set to its initial state and waits for the next control pulse 18 from the photosensor 6 of synchronous signals. The manufacturing accuracy of the position feedback photosensor 13 and 5 the choice of the response level of the threshold element 14 determines the accuracy of the film I pulling, while the frame pitch is determined by the operation mode of the position feedback photosensor 13.

Claims (2)

1. USSR author's certificate JVo Ш5812, cl. G 03 21/44, 1965. 2. US patent number 3819258, cl. 352-163; 1974 (prototype).