SU1290173A1 - Stroboscopic tachometer - Google Patents

Abstract

The invention relates to a measurement technique and can provide a reading of the frequency of rotation of pulleys, drums and other objects. The purpose of the invention is to expand the area of unambiguous reading of the stroboscopic tachometer, which has a disk 1 rotating at a measured speed, pulse lights 4 and 5, one with red 6 and the other with green 7 light filters. On the dark surface of the disk there are two white marks 2 and 3 located on the radii forming an angle of if 360 ° / n, where n 1. Pulse illuminators 4 and 5 are connected to control device 10 containing a pulse generator 11, ring scaler 12 The electronic keys 13 and 14 linking the power source 15 to the pulsed illuminators 4 and 5. The control device 10 provides illumination of the disk with white marks 2 and 3 pairs of pulsed flashes, where the green flash lags behind the red for a certain time. Stopping the visible image of the rotating disk 1 can be achieved with different ratios of the period of rotation of the disk 1 and the pulse periods of the pulse generator 11. 3il. g (l fia}

Description

1: 12

The invention relates to a measuring technique and can be used for non-contact measurement of the frequency of rotation of shafts, pulleys, drums and other parts of various mechanisms.

The purpose of the invention is to expand the field of unambiguous reading of the stroboscopic tachometer.

Fig. 1 shows a general view of a stroboscopic tachometer and a diagram of a control device for pulsed illuminators; Fig. 2 shows visible images of rotational disk marks when a stroboscopic tachometer is operated; Fig. 3 is a diagram of an annular scaler.

The stroboscopic tachometer contains a dark disk 1 rotating at a measured speed. On the two radii of this disk, forming an angle

360 °

 where n 1, at equal distances from the center, two identical marks 2 and 3 are applied. Against disk 1 there are two pulsed illuminators 4 and 5 (one of which is equipped with red 6 and the other with green 7 light filters) connected to the outputs 8 and 9 of the control device 10 comprising a pulse generator 11 with an adjustable period T, an annular counting device 12, the outputs of which are connected to the control inputs of electronic switches 13 and 14 connecting the power supply 15 to the illuminators 4 and 5.

In the general case, the counting device 12. contains a binary counter 16 with a capacity of n and a decoder 17 of the state of the counter 16, and the decoder 17 has only outputs with the numbers (n-1) and n corresponding to the filling: counter 16 (n-1) pulses and n pulses. Conclusions from the rest of the outputs of the decoder 17 in this case as superfluous are absent.

The input of counter 16 is combined with one of the inputs of the decoder 17 and connected to the output of the generator 11. The remaining inputs of the decoder 17 are connected to the outputs of the counter 16, and (n-1) and the p-th outputs of the decoder 17 are connected to the control outputs of the electronic keys 13 and 14 respectively.

Strobe tachometer works as follows.

732

Upon receipt of 11 pulses from the generator to the input of the ring scaler 12 to (n-1), and the output of the decoder 17 passes each pulse with a serial number (n-1) + + a, where a 0,1,2, ... Each impulse with the sequence number n + a, i.e. the lag of one output pulse of the ring scaler 12 from the other output pulse is 1 / n part of the follow-up period of these pulses equal to T T n.

These pulses unlock the electronic keys 13 and 14 and, when connected to the power supply source 15, the illuminators 4 or 5, turn them on, causing, due to the presence of the light filters 6 and 7, one after another short red and green flashes of light directed towards the rotating light. with a measurable speed disk 1 with marks 2 and 3.

Thus, the control device 10 provides illumination of a disk with labels 2. and 3 pairs of pulsed flashes (first red and then green), following with a period of. T T n, and at any period of the following pairs of flashes a green flash is lagging behind red for time

T

 - ". P

When operating the device, stopping the visible image of the rotating disk 1 can be achieved with different ratios of the period of rotation of the disk 1 and the period of the pulse of the generator 11.

Let with a certain period T,., Following the flashes of the illuminators 4 and 5 and with the lag of the green light.

veterans 4 at time t - extensible

P

image of disk 1 is stopped .. If the period T "is slightly less than the period of rotation of disk 1, then the image of disk 1 with marks 2 and 3 (the angle between

360.

which looks as follows.

At the time of the green flashlight illuminator 5, label 2 takes place between the radius of the OB and OD, mark 3 takes place between the radius of the coolant and OI. Both labels reflect green light. It is important that in the sector between the radii of the exhaust gas and the OD two reflections are observed: red from mark 3 and green from

 312901

marks 2. The small time interval between these two flashes leads to the fact that the light reflected by the marks in this sector is perceived as yellow.

Thus, the operator observing the image of the rotating disk 1 sees three images of marks arranged in the direction of rotation of the disk 1 in the following order: red mark, jo three-color mark consisting of radially green, yellow and red stripes, and green label

Similarly, if the stop of the image of disk 1 has reached and with a period of J5 T slightly longer than the period of rotation of disk 1, then the operator watching the image of the rotating disk 1 sees three images of marks 2 and 3 located in the direction of rotation 2 of disk 1 in the following order : red, label, three-color label of red, yellow and green radial stripes, green label.

The more the disc 1 image is stopped when the disc 1 turns on and the period T of the flashes of the lights illuminates, the smaller is the width of the yellow bar in the middle mark. In principle, there can be no yellow bar in the image of the middle mark, then the middle mark splits into two (red and green) and the operator observes four marks: two red and two green, which also indicates inequality

35

period of rotation of disk 1 and period T ".

With exact equality of the period T and the period T of the rotation of the disk 1, the positions of the radii of OB and EG, as well as the OD and OE are in pairs, because during the time T between the lights of 4 and 5, the disk 1 rotates

H and label 2 takes when green

the same place that the red mark occupied with the red flash was 3. The operator, observing the image of the rotating disk 1, at the same time sees three fixed monochrome marks

734

the same size, respectively, red, yellow and green colors (the sequence of colors is shown in the direction of rotation of the disk 1). The rotation period of disk 1 is

T TP (p + 1G, where q 0,1,2 ..

jo

J5 o

five

five

0

0

To obtain the same image on the rotating disk 1 at a different frequency of rotation of the latter and a constant period T of output pulses of the generator 11, it would be necessary to increase the frequency of rotation of disk 1 by (n + 1) times (i.e. the indications of the proposed tachometer could be confused with the frequency of rotation of the disk 1, equal, for example, to 60 and 6060 revolutions per minute). Within such a wide range of rotational frequencies, the tachometer reading is unambiguous.

Claims (1)

Invention Formula A stroboscopic tachometer containing a p-tunable pulse generator, a disk mounted on the object under study, two pulsed lights illuminated in front of the disk, connected to a power source, one of which is supplied with red and the other with green in order to expand the area of unambiguous reading, the disk surface is made dark with two identical white marks located at equal distances from the center of the disk along the radii forming an angle of 4 360 ° / n, where n 1 is integer In addition, a ring scaling device with a capacitance of n pulses and two electronic keys were additionally introduced, two pulsed illuminators were connected to the power source via electronic keys, the control inputs of which are connected to the (n – 1) -th and n-th output . The counting device, the input of which is connected to the output of the generator. A f: f Editor A.Revin Compiled by Y. Vlasov Tehred l. Serdyukova Order 7893/39 Circulation 798 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 ftuf.3 l- / 4 Proofreader L. Patay