SU876425A2 - Automatic controlling method of operating condition of table vibrator with loose gripping of mould for shaping articles - Google Patents

Description

(54) AUTOMATIC CONTROL METHOD

OPERATING MODE OF VIBRATION AREA WITH FREE

PRESSING THE FORM FOR FORMING PRODUCTS

The invention relates to the building materials industry, in particular, to methods for forming reinforced concrete products in on-board walkways with vertically oriented chambers.

According to the main author. St. No. 774942 discloses a method for automatically controlling the mode of operation of vibrating pads with free pressing of a mold for molding articles, which includes forming signals at the moment of striking the working device on the mold with a concrete mixture and at the time of unbalance of the optimal position and ensuring that both pulses change the rotation speed of the unbalances. In this cnoco6ie, the height and the degree of compaction of the concrete mixture being laid in the form are measured. unbalance changes the intensity of the effect between the actual and calculated ziache-. nor amplitude of the driving force. is he

provides for a change in the process of molding only the amplitude of vibrations and the amplitude of external influences.

However, this method does not provide uniform compaction, since it does not change the natural frequency of the shape with the concrete mixture to achieve equality with the optimum frequency of the concrete mix (before the resonance occurs in the form-concrete mixture system) and maintain the resonance during the molding process.

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The purpose of the invention is to increase the uniformity of compaction of the concrete mix.

This goal is achieved by the fact that in the method of automatic control of the mode of operation of vibrating platforms with free

5, pressing the mold to form products additionally builds a calibration dependence of the optimum vibration frequency values on the height and degree of compaction of the concrete mix; for the measured values of the layer thickness and its degree of compaction, the optimum vibration frequency values are determined by the calibration dependence, compared with the actual values by comparison and regulation of the force of pressing the form to the exciter pathogen, they change the natural frequency of the op. with the concrete with a sma for compacted concrete mix.

The drawing shows the functionality of the diagram of the device that implements the proposed method.

For the concrete mixture 2 used in molding 1, the calibration dependences between the optimal amplitude of the driving force P. are built, the optimum frequency of oscillations and the height of the concrete mixture at various degrees of compaction, i.e. Pp f, (H, S); w fj (H, S) /

The dependency Pp f ((HiS) lays on the basis of the operation of the functional converter 3, whose task is to form at the output a signal corresponding to the optimal (calculated) amplitude of the driving force Pp (for example, the amplitude Pp at a height of one hundred concrete mixture H (and the degree of its compaction S).

The dependence tJe fa.OtS), expressed through the magnitude of the pressing force of form I to the exciter 4 by means of springs 5, 25, forms the basis of the operation of the functional converter 6, the task of which is to form at the output a signal corresponding to the optimal (calculated) value of the natural frequency with a concrete mix placed in a syu (c (n (n))).

With the help of the height sensor 7 and the degree of compaction (density) sensor 8 of the concrete mix, the height value H and the degree S of compression are measured and converted into signals that are fed to the corresponding opposite inputs, functional converters 3 and 6,

From the output of the converter 3, the signal Pp of the optimal (calculated) amplitude of the driving force is removed and sent 4o as a reference to one of the outputs of the comparison element 9, to the other input of which from the sensor 10 a signal Yar characterizing the actual amplitude of the driving force is applied. The difference of the signals at the output of the comparison element 9 is supplied to the executive unit 11, which generates signals that control the drive of the regulator 12 for changing the amplitude of the driving force until equality between RF and Pp. The required change in the magnitude F of the actual amplitude of the driving force can be achieved, for example, by a corresponding change in the moment of eccentrics (the static moment of the mass of the Balances 13)

In the second control channel from the output of the $ 5 converter 6, the signal Fp of the optimal (calculated) value of the pressing force of the form, which characterizes the achievement of

equal to the natural frequency of the form and the optimal frequency for concrete, and is sent as a reference to one of the inputs of the comparison element 14, to the other input of which from the sensor 15 is supplied the signal Rp, reflecting the magnitude of the actual pressing force of form I to the exciter 4 by springs 5 through elastic pads 16. The difference between the DR Pp-Rp signals at the output of the comparison element 14 is supplied to the actuator 17, which provides, for example, by varying the amount of compression of the springs 5, the required regulation of the pressing force of the form until reaching equality between RC and RR.

The tuning to the resonant mode (third control channel) of the vibrator-shape system is carried out in a manner known per se. For this, a special control channel is provided, consisting of an unbalance position sensor 18 at the moment of impact, an unbalance moment sensor 19 of the optimum position, a converter 20 and an actuator 21 controlling the rotational speed of the drive motor 22,

In those cases when the pulses from sensors 18 and 19 do not coincide in time and are dependent on the magnitude and mismatch sign, converter 20 generates a control signal by which actuator 21 performs the required adjustment of the oscillation exciter from the shaft while moving. coincidence of these signals in time and thus ensuring the retention of a given mode of operation.

Claims (1)

Invention Formula A method for automatically controlling the mode of operation of vibrating platforms with a free pressing of the mold to form products according to the author. St. No. 774942, characterized in that, in order to increase the uniformity of compaction of the concrete mix, the calibration dependence of the optimal values of the vibration frequency on the height and the degree of compaction of the concrete mix is additionally constructed, and the measured values of the measured values of the height of the layer and its compression ratio are determined by the calibration dependence oscillations, compare them with the actual values and, based on the results of the comparison, by adjusting the magnitude of the force. with the concrete mix to equal the optimum frequency for the layer to be compacted concrete mix. Sources of information taken into account Gary examination 1. USSR Copyright Certificate № 774942, cl. B 28 B 1/08, 1978.