SU1744451A1 - Projector for measurement of linear dimensions of parts - Google Patents

Abstract

The invention relates to a measurement technique and can be used for non-contact measurement of the linear dimensions of parts. The aim of the invention is to improve the accuracy and the expansion of the measurement range by using the mechanism of orientation of the ends of the light-conducting collector to a normally incident light beam when the measurement range is changed. During the measurement, the controlled part 16 is installed on the measuring station 2. Using the radiation source 1 and the lens 3, a projection is obtained on the screen 4. The contours of the projection using screws 9, 8, 8, carriages 5 set the branches 12 to the working position. The carriage 5 is pressed against the guides 6 and 7 using a V-shaped spring 10. The center of the end of the branch 12 moves B to the projection plane by moving the axis of one carriage in the guides 6 and the other axis in the guides 7. At the same time the carriage 5 rotates relative to the axis and orients the plane of the end of the branch 12 perpendicular to the direction of the light beam. 2 hp ff, 4 ill. (Ls

Description

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four

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The invention relates to an instrumentation technique and can be used for contactless measurement of the linear dimensions of parts.

A known optical system for monitoring parts, comprising a sequentially installed and optically interconnected illuminator, a measuring station with a drive unit, an optical system, a light-emitting diode collector with branches, a position-sensitive photodetector, a control unit, the output of which is connected to

photoreceiver input, binary signal generating unit, interface, computer.

A disadvantage of this device is the low measurement accuracy and the impossibility of measuring parts of different types, since each branch of the light guide collector is rigidly fixed in the projection plane of the part fragments.

A projection device for measuring the linear dimensions of objects, taken as a prototype containing a projector, two photodetectors in the form of linear video drivers, platforms, guides, a control unit, an information signal processing unit, is also known, the platform being installed on guides in the projection plane (screen projectors) with the possibility of their relative movement in it.

This device has a low measurement accuracy, because when moving in the plane of the screen, the angle of incidence of light on the linear video signal shapers changes when they are moved, which leads to a change in the distribution of light intensity on the surface of the photodetectors and, accordingly, the video signal from the photodetectors. the location of the platforms at the edges of the screen, which are significantly remote from the optical axis of the projector. This leads to an error in determining the size of the signals from the photodetectors. Photodetectors should not leave the projection plane, since this leads to an even larger error in determining the size due to both a change in the magnification factor and the defocusing of the projection.

Especially significant is the normality of the incidence of a light beam on the plane of the end of a light-water collector, since the light-guide collector has a small entrance aperture.

The aim of the invention is to improve the measurement accuracy due to the automatic orientation of the ends of the light guide collector to a normally falling beam when changing the range of measured sizes and expanding the measurement functionality.

This is achieved by the fact that a projection device for measuring the linear dimensions of parts, comprising a housing and successively installed in it an optically coupled radiation source, a measuring station, an objective lens, a screen with main guides, the axes of symmetry of which lie in the screen plane, the carriages mounted in the respective main guides with the possibility of longitudinal movement, the light guide block, the input ends of the branches of which are placed one on each of the carriages, the optoelectronic unit, is optically coupled first yield light guide unit, the control blocks and processing of information signals, electrically associated with opto-electronic unit is provided with additional guide on the number of main guide set the corresponding base guide in one

the plane, the normal plane of the screen, at an angle to them, parallel to the axes by the number of guides rigidly connected to the respective carriages and installed in each of the guides with the possibility of moving along them, the branches of the light guide block are fixed on the edges of the carriages so that the central fiber of each branch is located at a right angle to the axis established in the main guides, and the working surfaces of the additional guides are profiled in accordance with the dependence

oh xkd

Y -

d / ± Yl + (-O-

x - kd

where d is the distance between the axes; t is the distance between the focus of the lens and the screen plane; x is the distance from the optical axis of the objective to the axis of the carriage mounted in the main guides I K I 1.

In addition, each card is made in the form of a V-shaped slider connected to parallel axes and equipped with a V-shaped spring installed inside the slider, and the device is equipped with micrometric screws according to the number of carriages axial movement and pivotally connected to the carriage,

Figure 1 presents the structural diagram of the proposed device; figure 2 - screen module with the mechanism for installing the end of the branch of the light guide collector; on fig.Z - section aa in figure 2; Fig. 4 shows a carriage design in which the ha with the spring are combined.

A projection device for measuring the linear dimensions of parts contains a source of radiation 1, a measuring station 2 (for example, a mandrel), a lens 3, a screen 4, a carriage 5, main guides 6, additional guides 7, tgu 8, micrometric screw 9, spring 10 , light guide block 11c with branches 12, optoelectronic block 13, block 14 of control and block 15 of information processing.

The radiation source, the measuring station 2, the lens 3 are located in the housing successively on the same optical axis, and the screen 4 is installed so that the main guides 7 are located in the plane of projection of the part 16 installed in the measuring station 2. The light-guiding unit 11 is optically connected with opto-electronic

unit 13, the input of which is connected to the output of the processing unit 15.

The carriage 5 (FIG. 2) has two axes 17, 18, one of which 17 is installed in the main guides 6, and the other 18 is in additional guides 7. The branch 12 of the light-guiding unit 11 is rigidly fixed on the edge of the carriage 5 so that that the optical axis of the central fiber of the branch 12 is located at a right angle to the axis 17, perpendicular to the axis installed in the main guides 6. The geometrical center of the end face of the branch 12 lies in the plane of projection of the part 16 installed in the measuring station 2.

Additional guides 7 (Fig. 1) are located in the plane, the normal projection plane and passing through the main guides 6 and their working surfaces are made according to the profile described by the formula:

R

,

oh xkd

d / ± Yl + (- “Y,,

x-kd

where d is the distance between the axles of the carriage 5; C is the distance between the focus of the lens 3 and the plane of the screen 4; x is the distance from the optical axis of the objective 3 to the axis 17 of the carriage 5 installed in the main guide 6,

K 1 and the + sign in front of the root, with additional guides in front of the main ones; K 1 and the sign - before the root - otherwise.

When -j-1 additional guides can be made at an angle arctg-p to the main

guide 6.

A tg 8 is installed in the main guide 7 and pivotally connected to the carriage 5, the micrometer screw 9 is threadedly connected to the screen 4 and the grip 8. A compression spring 10 is installed between the glue 8 and the platform.

The carriage 5 (FIG. 4) can be made as one whole with a thrust 8, from a single plate with a weakened section at the point of their connection, which allows to simplify the design and dispense with the spring 10, which is played by the weakened part of the carriage 5,

The device works as follows.

In the initial state, a sample part 16, the size of which is in the middle of the tolerance floor, is installed in measuring station 2. A radiation source 1 illuminates the part with a collimated beam (light), the lens 3 forms a clear projection of the part on the screen 4. Along the projection contour with a micrometer screw 9 and 8, carriages 5 are installed so that the projection border passes through the optical axis of the corresponding branch 12. Spring 10 presses carriage 5 to the guides

0 6.7.

This installation of the carriages 5 is controlled as follows. The control unit 14 scans a position-sensitive photodetector (e.g., a CCD array),

5, which is part of the opto-electronic unit 13 (not shown in FIG. 1). The information signal from the opto-electronic unit 13 enters the information processing unit 15, which processes this signal and

0 displays information about the position of the light-shadow border on the photosensitive surface of the photodetector in the selected rows, which are based on the design of the device and its alignment. (As

5 of the information processing unit, a video monitor may be used).

The position of the light-shadow border at the center of the end of the branch 12 corresponds to a certain number of illuminated cells of the photodetector. The device is calibrated in the usual way by installing parts of a known size followed by recording the readings of the information processing unit 15.

Next, the measuring part is inserted into the measuring station 2 and the readings of the information processing unit are recorded. When changing the type of the measured part, the dimensions of which go beyond the measurement range at this position of the wind guide 12 of the light guide unit 11, the microcarving screw 5 moves the carriage 5 with a rod 8 with the branch 12 rigidly fixed in it to a new - the shadow again appears in the center of the end of the branch of the light guide unit 11. At the same time, the center of the end of the branch 12 moves in a plane in which the projection is always clear (projection plane), since the axis 17 of the carriage 5 moves to

0 main directions 6 located in the projection plane. When the second axis 18 of the carriage 5 moves in the additional guide 7, the carriage 5 rotates relative to the first axis 17 so that the plane of the end face of the branch 12 is always perpendicular to the direction of the light beam incident on it, which is provided by the profile of the additional guide 7 described by the above formula.

When the carriage 5 is moved to the optical axis with the help of the micrometer screw 9 through the tube 8, the carriage is turned when its axis 18 is moved in the additional guides 7 in the opposite direction and the end of the branch 12 of the light guide block is again normal to the incident beam.

If it is necessary to move the ends of the branches 12 of the light guide block 11 in the plane of projection in a direction perpendicular to the X-axis, a screen 5 of a similar design is used, with main and additional guides arranged respectively in the plane of projection and the plane normal to it passing through these main directions carriage, and the role of the carriage performs the described screen, equipped with two axes.

Thus, the proposed technical solution allows the device to be rebuilt with a change in the measurement range, while the center of the end of the branch of the light guide block is always in the projection plane, and the end face plane is perpendicular to the light beam incident on it, which is especially important for the light guide block. entrance aperture. This allows you to transfer a clear light-shade projection boundary in a wide range of measured dimensions from the projection plane to the opto-electronic unit, which improves the measurement accuracy and extends the functionality by expanding the measurement range. In addition, the readjustment time of the device is reduced by eliminating the alignment time of the light guide body.

Claims (3)

Claim 1. Projection device for measuring linear dimensions of parts, comprising a housing and optically coupled radiation source, measuring station, lens, screen with main guides sequentially installed, whose axes of symmetry lie in the screen plane, carriages mounted in respective main guides with the possibility of longitudinal movement, a light guide block, the input ends of the branches of which are placed one on each of the platforms, an optical-electronic unit optically coupled with the output of the light guide unit, the control and processing units of the information signals electrically connected with the optical-electronic unit, characterized in that, in order to increase the accuracy and expansion measurement range, it is provided with additional guides according to the number of main guides set at an angle to the corresponding main guides, parallel to the hinge axes according to the number of guides rigidly connected with the corresponding carriages and installed in each of the guides with the possibility of moving along them, the branches of the light guide block are fixed the ends of the carriages so that the axis of the central fiber of each branch intersects at a right angle with the corresponding hinge axis installed in the main guide, the end of the central fiber parallel to the hinge axis, and the working surfaces of the additional guides are profiled in accordance with the dependence thirty oh x kd Have where d is the distance between the axes of the carriage; - the distance between the focus of the lens and the screen plane; x is the distance from the optical axis of the lens to the axis installed in the main guides I K 1. 2. Pop-1 device, characterized in that the carriage is made in the form of a V-shaped slide, the ends of which are fastened to the expanding V-shaped spring installed inside it. 3. Pop-1 device, characterized in that it is provided with micrometric screws according to the number of carriages, each of which is mounted on the screen with the possibility of axial movement and pivotally connected with the carriage. / / V-v Mr. MF Zl LI 8 II / / 01 Ј 2Pf CH77A-: pn  .. -1-3.-s.i -d.4 yu 1917 frfril 1A 185I LT i Type A