SU736167A1 - Start-stop tape-driving mechanism - Google Patents

Description

I

The invention relates to instrumentation, namely, devices for moving the tape carrier information.

A start-stop tape-driving mechanism (LPM) is known, in which the tape carrier during operation in the starting mode is pressed by the roller controlled by the pressure to the rotating element or the driving element - the shaft or roller, and in the stop mode by the controlled brake element (bar, roller ) is pressed against the fixed stop 1. Such a device has a high speed in start-stop mode.

However, this device is structurally complex (especially in the control elements of the pressure roller and brake assembly) and, besides, considerable electrical energy is expended on the rotation of the driving element and in the control electromagnetic elements.

The closest in technical essence to the present invention is a high-speed start-stop tape-driving mechanism comprising a pressure roller mounted in a bracket, a reciprocating transducer rigidly connected with it.

oscillations, connected via a switch to a generator and to a voltage source, as well as a shaft periodically mated through a tape carrier with a pressure roller 2 .. 5 In this device, the control electromagnetic devices that are complex and consume significant electrical power are replaced by economical and faster ones control elements made in the form of piezoceramic elements and operating using the inverse piezoelectric effect.

However, in this device, the complexity of the start-stop mode of operation is not eliminated. The start-stop mode here is provided by two alternately controlled units (leading and pressure roller) and two braking brakes. The rotation of the drive roller still consumes a considerable amount of electrical power. In addition, the presence of a high-inertia drive element reduces the overall speed of the whole mechanism, since it takes an appropriate amount of time to accelerate it. In order to eliminate the latter drawback, the driving element is made constantly rotating, and electric energy is additionally spent on it in the standby mode of operation of the LLM. The purpose of the invention is to simplify the increase in speed and efficiency of the mechanism. This goal is achieved by the fact that, in a known start-stop tape-driving mechanism, comprising a pressure roller mounted in the bracket, a piezo-transducer of reciprocating oscillations rigidly connected with it, connected through a switch to the generator and to a voltage source, as well as a shaft, periodically mating through a tape carrier with a pressure roller, a piezotransducer of torsional vibrations is inserted, fastened to the shaft and electrically connected to the second output of the switch, while the shaft is in place of the coupling with the tapes The internal carrier is made with an annular groove, the length of which is equal to the width of the tape carrier, and the depth-thickness of the same carrier. FIG. 1 shows one of the variants of the proposed device (a variant with electric control of a pressure roller) in FIG. 2 is a view along arrow A in FIG. 1. The device consists of a torsional oscillation piezotransducer 1, a piezoceramic element 2 bonded in any known manner with a piezotransducer 1, preferably in one of the antinodes of its oscillations, a pressure roller 3 rigidly connected by a clamp 4 with an end of a control bimorph piezoelectric converter reciprocating element 5 , tape media 6, placed in the groove 7 of the piezoelectric transducer 1, the input source 8, connected through a switching device 9 with the element 5, the generator This is an electrical excitation 10 connected through a switching device 9 with element 2, and women And, which receive control commands to the switching device 9. In FIG. Figure 2 shows an imaginary general geometrical plane 12 of symmetry of the pressure roller 3 and the piezoelectric transducer 1 and one of the working positions of the element relative to this plane of rotation direction while the pressure roller 3 and carrier movement 6. The tape drive mechanism works as follows. When the starting command for moving the carrier 5 to the busses 11, the switching device 9 connects the source 8 to the element 5, and under the action of its output signal, the latter bends down, presses the roller 3 to the piezoelectric transducer 1, simultaneously pressing to it and the carrier 6. For the same The command device 9 connects the output of the excitation generator 10 to the electrodes of the piezoceramic element 2, which, excited at one of the natural frequencies, causes resonant bending oscillations in the piezoelectric transducer 1. At the same time Adding oscillation piezoelectric transducer is chosen so that it does not coincide with an imaginary common geometric plane of symmetry 12 {plane extending through the geometric axis of the pressure roller 3 and the piezoelectric transducer 1), otherwise the displacement of the information carrier 6 will be difficult. The choice of this direction is easily accomplished, for example, by rotating the element 2 around the axis of the piezotransducer 1. The vibrating piezotransducer 1 due to shock coupling with the pressure roller 3 causes the latter to rotate, and due to the presence of friction coupling of the roller 3 with the carrier 6, the latter is set in motion relative to the surface of the guide annular groove 7 on the piezoelectric transducer 1. The presence of the annular groove 7 ensures simultaneous friction contact of the roller 3 with the piezoelectric generator 1 {roller height greater than the groove width) and with the carrier 6, leaving a sliding contact between the carrier and the resonator. The excited piezoelectric transducer 1 exerts a very weak brakes n ee: 1, acting on the carrier 6, which ensures its easy movement. This effect is also promoted by the torsional vibrations arising in the rod of the piezoelectric transducer 1. The direction of displacement of the carrier 6 is determined by the mutual constructive arrangement of the elements of the tape mechanism, and its linear speed can be adjusted by changing the frequency and amplitude of the output signal of the excitation generator 10. When a bus arrives The commands of the "Stop switching device 9" command automatically stop the supply of the excitation signal from the output of the generator 10 to the element 2, and the oscillations stop. The transducer 1 and the above-mentioned friction links of the “resonator-carrier-roller” link instantly stop the movement of the carrier 6. The low-inertial pressing roller 3 doesn’t delay the temporary braking process of the carrier 6. When rewinding the carrier 6, the corresponding co-driver on bus 11 of the switching device 9, the signal to the piezoelectric element 5 from the output of the source 8 is terminated, the frictional contact "roller-resonator is violated and the carrier 6 is released. Simultaneously from the output of the excitation generator 10, it is reduced ny amplitude signal to element 2, which excites pezopreobrazovate / 1b 1 with a lower intensity. These small high-frequency oscillations of the piezoelectric transducer 1 provide an effective reduction of friction between the carrier 6 and the piezoelectric transducer when rewinding the carrier. This reduces the wear of the carrier and the resonator in the region of the guide annular groove 7.

The proposed device also provides continuous movement of tape media. It performs this function on the start command until a stop command is received (“Stop”). In this case, the movement of the carrier is characterized by a rather high uniformity.

Claims (2)

1. USSR author's certificate number 449373, cl. G 11 B 15/43, 1974. 2. USSR author's certificate No. 297993, cl. G 11 In 15/28, 1968 (prototype) Xi w 12 FIG. 2