DE955270C - Machine for automatic recording of the cross-section of machine parts - Google Patents

Description

ISSUED JANUARY 3, 1957

A 20864IX / 42 a

is used

The invention relates to a machine for automatically recording the outline of a machine part by means of a magnifying lever system which has a rotatably mounted feeler roller for scanning the outlines of the machine part. Such a machine is used in mechanical engineering for checking more or less complicated outline designs of machine parts, but especially for checking turbine blades, e.g. B. of ⁰ nozzle motors, use, There are known various types of devices for checking the outline shape of machine parts. They differ in whether mechanical or optical means are used for enlargement.

The optical means make it possible to project an enlarged image of the various cross-sections of the machine part to be tested in appropriately selected levels. The projection takes place either on tracing paper or on light-sensitive

Paper. The outline is created either by photographic development or by hand shown by the examiner following the outlines with the pen.

In both cases, the reproduction is inaccurate. Change during photographic processing the dimensions of the photosensitive paper after treatment in the various Bathing and drying. When tracing ίο the outlines by hand on tracing paper is the Accuracy of reproduction depends on the hand of the person and therefore usually only limited.

In the case of mechanical means, these aforementioned inaccuracies do not occur in the reproduction on. There are machines known in which the outline of the machine part with a point, for. B. a tactile finger or a caliper, scanned by the handlebars of a pantograph verao greater! and with the help of a second point that slides directly on the sheet of paper, followed by ^ is drawn. However, the exact reproduction of the scanned outlines on a sheet requires in these cases that the diameter of the probing part is not larger than the diameter of the die Records executive tip.

Now, however, the pressure exerted by the probe tip on the machine part to be tested is due to this limited that this point may not leave any trace on the machine part. The one on the tip of the drawing The transmitted force changes like the pressure on the button divided by the enlargement number. This force is of the same order as the frictional resistance of the pen on top of it Paper. This results in deviations that are greater, the greater the magnification, so that the accuracy achieved is even worse than with optical means.

Furthermore, a device for producing the profile of copying cams is known in which a Roller is used for scanning. The roll is mounted on a lever and is driven by a rotating one Original cams from via corresponding intermediate links according to the for the copying process known principle of the cranesbill controlled. With such a device, however, can a more precisely enlarged outline of the original cam can never be obtained.

With a machine according to the invention, an accurate enlarged image of the outlines of a Machine part received, and the inaccuracies occurring in known machines and devices are avoided.

The machine according to the invention is characterized by a drawing head on a Drawing disk automatically records circles whose diameter is equal to the diameter of the feeler roller multiplied by the magnification ratio is.

The drawing head preferably has an axis which is parallel to the plane of the drawing and which is at the ends is provided with two identical, loosely mounted character wheels and one is essentially vertical to the plane of the drawing and the same distance from the two drawing wheels having axis is attached, which is set in rotation by a motor.

In order to avoid any stalling during recording, the relative movement of the scanning roller automatically controlled on the outline by one or the other of two electric motors that each set the drawing disc with the object to be tested in rotation, if the resistance of this disc in the direction of rotation is below a certain value, or the Operate the shaft of the rod carrying the drawing head, if the resistance of the disc in the direction of rotation is greater than this same value.

The machine according to the invention can also be provided with a stopping device which starts automatically while the motor driving the shaft of the character stick is running, when the resistance of this shaft in the pivoting direction exceeds a certain value. Further Means can be provided by which the machine can be operated again after this standstill is set.

The machine can also be provided with a manual control device which, when driving the Drawing disc by the motor allows the speed of rotation of this motor to be reduced, if the normal speed causes an angular speed of the character stick that is too high, from which a friction of the drawing head on the drawing disk results, through which the contact can be canceled between the scanning roller and the object to be tested.

An exemplary embodiment of the subject matter of the invention is shown in the drawing.

Fig. Ι is a perspective view of the character head;

Fig. 2 is a schematic plan view of the essential parts of the machine;

Fig. 3 is a perspective view of these parts;

4 is a schematic representation in a plane extending parallel to the drawing disk and FIG shows the arrangement of the outline to be scanned and the feeler roller with respect to the axes of FIG Drawing washer and roller lever at normal no Work;

Fig. 5 shows schematically a borderline case in which the force exerted by the contour on the follower roller is entirely transferred to the roller lever;

Fig. 6 shows the manner in which certain parts of the outline cannot be removed from the follower roller by simple rotation in the same direction can be overrun ';

Fig. 7 shows in which case the angular velocity the roller lever becomes excessive;

8 and 9 show the drive motor of the drawing disk in the working and in the rest position and an automatic device for switching this motor off and on and for switching it on or off Disengaging the drive motor for the shaft of the drawing rod; ·

Fig. Ίο shows the drive motor of the shaft of the The stick and the clutch of this engine;

Fig. Ii shows the automatic shutdown device in the linkage of this motor;

Fig. 12 is an electrical circuit diagram of the machine.

The character stick ι carries at the free end a character head 21 with a horizontal support axis 2, on the ends of which two identical knurled drawing wheels 3 and 4 are loosely rotatably mounted, which are at an equal distance from a vertical pivot 5, which is rotatable in a Bearing 6 of the character rod 1 is mounted and rotated by a small electric motor 7 will. A ball joint shown schematically at 8 transmits the rotary movement to the support shaft 2 and the drawing wheels 3 and 4 in a horizontal plane.

The drawing head 21 created in this way rests on a sheet of paper which covers or is covered by a sheet of carbon paper. In a certain position of the character stick 1, the head draws a circle 9, the diameter of which is equal to the distance between the character wheels. 3 and 4. If the scanning roller has a diameter of 10 mm and a five-fold magnification is used, a distance of 50 mm is selected between the drawing wheels. The circle 9 then also has a diameter of 50 mm and represents exactly five times the magnification of the image of the scanning roller 13.

When the follower roller 13 shifts, the drawing rod 1 moves the drawing head and the drawing head pulls in a continuous manner circles, which represent this shift with five times magnification. A continuous image of the successive layers of the scanning roller, and the movements of the drawing head take place without friction, because the drawing wheels are

run twice parallel to the trajectory.

This makes it possible to press the scanning roller against the object to be tested with little force and still get a very precise image of the outline formed by the envelope curve of the circles.

Of the. The object 10 to be tested is fastened to a drawing disk 11 which is rotatably mounted about a vertical axis 12. The scanning roller 13, which is firmly connected to a vertical shaft 15 by a lever 14, is pivoted by the levers 16, 17 and a link 18 which forms a joint parallelogram with them, a vertical shaft 19 which carries the drawing stick 1, at the end of which the drawing head 21 is attached. The rod 1 can also oscillate in a vertical plane about a joint 20 of the shaft 19.

The axis 12 and the axes of the shafts 15 and 19 are parallel and lie in the same plane.

The distances between the axis 12 and the axes of the shafts 15 and 19 are in relation to one another same ratio as the lengths of levers 14 and i. While the disk 11 is rotating under these conditions the path of the drawing head 2.1 on this disk is homothetic to the Path of the follower roller 13 in relation to the axis 12 the disc. If you choose 13 for the diameter of the roller and for the distance between the drawing wheels 3 and 4 values that correspond to the homothetic ratio, see above if the inner envelope curve of the drawn circles is also homothetic to the outline scanned by the roller 13, then that this envelope curve represents an enlargement of the outline.

The shaft 15 is parallel to its axis with one provided running flattening on which a holder 22 can slide and be clamped, which carries the lever 14 with the follower roller 13. This device allows the follower roller 13 without further parallel to the shaft 15 while maintaining to move the angular position so that any number of outlines selected in the height of the object can be changed without changing the reference axes on the disk 11, for all Cases are chosen once and which are in a certain position to the main axes of the object after its attachment in the pliers 23 are located in the extension of the axis 12 of the Disk 11 lies.

The follower roller 13 will go to the tested Object pressed by a long spring 24, which is inclined in the by the handlebars 18 and the two Lever 16, 17 formed parallelogram is stretched and their action by shifting the one end 25 along the lever 16 can be adjusted.

With this device it is possible to achieve the desired Generating pressure without friction, which results in deviations in the recording could, as by the usual devices with counterweight and. Sheave generated will.

The sheet of paper used for recording is attached to the drawing disk by any means, in particular by small magnets that are attached to the disc made of steel are put on ,. This type of fastening is facilitated by that the head 21 can be raised by pivoting the rod 1 about the joint 20.

The rotational movement of the disc for scanning the object 10 by the roller 13 and the Recording by the movements of the head 21 on the sheet of paper can be done by a small Electric motor 27 are generated, which the disc 11 in the manner shown in FIGS. 8, 9 and 12 with the aid of a small roller 26 which runs on the knurled edge of the disc 11.

From Fig. 4 it can be seen in what way the force resulting from the rotational movement of the disc 11 is transmitted to the lever 14 carrying the scanning roller and the rod 1 running parallel to it through the outline of the object 10 to be tested. In this figure, I denotes the axis of rotation of the disk 11 and of the object to be tested, which is denoted by 12 in FIGS. P is the profile of this object.

At every moment, the profile P exerts a force F on the follower roller 13 and its means, which runs at right angles to the profile at the point of contact M and passes through the center A. The movement S of the center A is a rotary movement around the axis ο of the shaft 15 (Fig. 3). The force F can be broken down into two components which emanate from the center A and of which one F _r goes radially through the axis ο, while the other F ₁ runs tangentially and at right angles to the former. The radial component F _r is destroyed in ο by the back force of the shaft 15. The tangential component F _t determines the movement of the follower roller and the character stick es.

A drive problem arises in the case of FIG. 5, where the perpendicular to the profile at the contact point M goes through the axis of rotation ο.

Here the tangential component F _{t is} equal to zero, and the force F falls with the component F ₁ .

together. The roller is no longer shifted, and the movements of the lever and the disc are 'blocked.

According to the invention, this problem is eliminated in the following way:

i. The motor 2J stops driving the disc;

2. the shaft 19 of the character rod is driven;

3. This drive stops automatically, and the first drive intervenes again as soon as the profile P with respect to the scanning roller again assumes the position according to FIG.

For this purpose, the drive motor of the disc is attached to a dynamometric holder, who moves to one side or the other when the transmitted force is a certain Limit. In the latter case controls the movement of the dynamometric Halters stopping the motor by any electrical or mechanical device. At the same time, this movement and a clutch create another drive device switched on, which causes the rotary movement of the shaft 19 of the character rod 1. Under this Under the influence of this, the follower roller moves further along the profile.

When, as a result of this movement, the scanning roller lies opposite the profile P again, as shown in FIG. 4, that is to say when the force F again has a tangential component F _t , the disk 11 is no longer locked. The force exerted by the drive device of the disc on the dynamometric holder falls below the set limit, and this drive device resumes its normal position. According to the invention, this return of the drive device to the normal position, by mechanical or electrical means known per se, causes the motor to be restarted and the clutch of the shaft of the drawing rod to be disengaged, these two effects being separated by a small period of time, thus avoiding any interruption of the curve should be avoided.

From Fig. 8 it can be seen that the motor 27 for driving the disc 11 with the drive roller 26 is arranged at one end of a link 28, the other end of which engages a lever 29, which is mounted on a stationary pin 32 by a joint 31. This joint engages a tension spring 30, the other end of which is suspended from a fixed point 33. The handlebars 28 is guided between two pins 34 and 35, which are counteracted by precisely matched springs 36 and 37 a stop of their housings 38 and 39 are pressed. The housings 38 and 39 are set in such a way that that the pins 34 and 35 leave exactly the gap between them that the smooth Passage of the handlebar 28 is permitted. When the driving force of the disk 11 in one sense or the other exceeds the value that corresponds to the pressure 8 » corresponds to the springs 38 and 39, the link 28 is pivoted about the joint 31 and presses for example the spring 38 with the help of the pin 34 together. This will be described in the below Way the braking and almost immediate stopping of the motor 27 causes so that the stopped Washer 11 is no longer subject to the action of pin 34, which is transmitted by roller 26 will.

When the switch 40 is actuated, the device shown in FIG. 10 is also activated set. The shaft 19 of the character rod 1 carries a Disc 44 which can be made magnetic by electrical means. The stream becomes this Purpose fed through the conductor 47 in a known manner to a solenoid. Axially opposite this disc rotates slowly and continuously another disc 45, for example made of mild steel, which is set in a uniform rotary motion by an electric motor 46. By the actuation of the switch 40 a direct current is supplied through the conductors 47, whereby the The magnetic clutch consisting of disks 44 and 45 is engaged and both disks practically connected to one another by the magnetic field. The motor 46 displaces thus the shaft 19 in a slow rotational movement and with this also the scanning roller 13 and the Character stick i, so that the machine follows the profile of the Blade continues to record, despite the fact that the disk χ ι is no longer driven.

"As soon as the follower roller 13 has been brought back onto the profile P by this movement, after the disc 11 has been rotated further by the spring 36 and the pin 34, the latter ceases to act on the switch 40, thus in the manner described below the motor 27 is switched on again and accordingly the disk 11 is driven again.

Closing the switch 40 also switches off the current of the magnetic coupling 44, and the cessation of the slow rotational movement of the shaft 19 and the follower roller 13 and des Character stick 1. To avoid any interruption of the recorded curve, it is advisable to shutdown by about 1 second

delay with respect to the moment of the new driving of the disc 11. This delay is achieved automatically in the manner described below.

Fig. 9 shows the dynamometric device with the drive motor 27 of the disk 11 and the seated on the motor shaft roller 26 in the rest position of the machine. The role 26 is no longer at the edge of the disk 11. The spring 30, those on the other side of the line 33-32 Lever 29 acts, holds the handlebar 28 in a position removed from the disc 11 and actuated the switch 42, which in this position switches off the current of the three motors 7, 27 and 46 and the The machine stops.

A stop 43 provided on the edge of the disk 11 causes the pivoting during the rotation of the lever 29 and stopping the machine at the end of the recorded curve. the Disc 11 no longer in contact with roller 26 can then be loosely rotated by hand. At the beginning of a recording, the handlebar 28 is first shifted by hand in such a way that the switch 42 released and the roller 26 against

as the stop 43 is printed. This will make the Disc driven by the motor 27, and the motors 7 and 46 are also turned on. As soon the stop 43 has passed the roller, the handlebar 28 again takes the one shown in FIG. 8 “Position one, and the curve will continue to be recorded.

Another difficulty can arise if, in the position according to FIG. 5, the tangential component F _t is reversed by the profile, as is indicated in FIG. 6. This component F _t then opposes the movement of the scanning roller. The further movement of the roller is only possible when the disk with the object 10 rotates in the opposite direction.

The suspension of the dynamometric device, which carries the drive roller 27, allows a short rotary movement in the opposite direction. If the part of the profile according to FIG. 6 is relatively short, the resilient movement allows recording. If this part is longer, however, the movement is blocked at the moment when the tangential component F _t becomes equal to the driving force of the follower roller. In order to avoid any unusual force which could cause a change in the shape of the machine parts, a force limiter of known type is switched on in the transmission of the motor 46 and the shaft 19, which switches off the power to the machine

and brings it to a standstill. Then you can continue to record, using the other direction of rotation of the disc.

Fig. 11 is an embodiment of the foregoing Safety device. The clutch

The disk 44 of the motor · 46 is not seated firmly on the shaft 19, but is loosely supported on it. she carries an arm 48 which strikes against a lever 17 when the disc rotates and this takes away. Between the lever 17 and the arm 48 there is a switch 49, which is under the action yields a certain pressure and is designed, for example, as a microswitch. If the pressure exerted by the arm 48 on the trigger of the switch 49 exceeds the selected value, the 'switch is opened and turns off the power to the machine.

A further operational difficulty can arise in the case of FIG. 7 when the profile P forms a fairly small angle with the lever IM . In this case, a small angular movement of the disk and the object about the axis / a large displacement of the Afotastrolle 13, thus also of the drawing head 21 can correspond. However, the speed of this latter is limited. From Fig. Ι it can be seen that it can only move without substantial friction when its displacement during one revolution of the character wheels 3 and 4 is small. In the present case, the drawing head 21 cannot move fast enough to keep the scanning roller 13 correctly in contact with the profile of the object 10, and the curve recorded is thus incorrect.

According to the invention, this difficulty is overcome in that the rotational speed the disc is reduced to a fraction of its normal speed, for example on the fourth part of this normal speed. Any braking device known per se can be used for this purpose that is put into action at the desired moment. The drive motor can be braked electrically, for example.

Fig. 12 shows an embodiment of the circuits of the different parts of the machine. The motor 7 of the drawing head can be found here again, the motor 27 of the drawing disk 11, which consists of two single-phase motors with opposite induction consists on a common shaft, and the motor 46, which drives the shaft 19 of the character rod 1 and the The drawing head. At 52, for example, alternating current is fed to a manual switch box 50, 51, the separate or simultaneous switching on of the motors, reversing and braking of the motor 27 and switching on the Coupling 44, 45 of the motor 46 is permitted. The braking of the motor 27 is achieved in that in the induction coil for the direction of rotation that is not used is one coming from a rectifier 54 Direct current is introduced. The clutch 44, 45 of the motor 46 is engaged by that in the disc 44 a rectified and smoothed, coming from the rectifier 56 Electricity is initiated. The actuation of one of the switches 40, 41 acts on a circuit relay 5.3 iao a, which switches off the current of the motor 27 and initiates a braking current through which this motor is stopped immediately. At the same time, a current is also passed into the coupling 44, 45 of the motor 46. When the switches 40 ', 41 return to the rest position occupy, relay 53 switches the brake

current of the motor 27 from and. the operating current of this motor immediately on again. The delay relay 55 maintains the feed current of the clutch 44, 45 for about 1 second.
The operating switch 42 and the safety switch 49 switch off the supply current to the machine without further ado, but the switch 42 can be bridged by the normal individual controls.

Claims (7)

PATENT CLAIMS: 1. Machine for automatic. Drawing the outline of a machine part using a magnifying lever system, which has a rotatably mounted feeler roller for scanning the outlines of the machine part, characterized by a drawing head (21) on a Drawing disk (11) automatically records circles (9), the diameter of which is equal to that with • the diameter of the feeler roller multiplied by the enlargement ratio. 2. Machine according to claim 1, characterized in that the character head is a for Has the plane of the drawing parallel axis (2), the s5 at the ends with two identical, loosely mounted Drawing wheels (3, 4) is provided and at a substantially perpendicular to the plane of the drawing standing and the same distance from the two drawing wheels (3, 4) having axis (5) is attached, which is set in rotation by a motor (7). 3. Machine according to claims 1 and 2, characterized in that the axis (2) with The axis of rotation (5) is connected via a ball joint. 4. Machine according to claim 1, characterized in that that the scanning roller (13) by means of an oblique in which serve for enlargement ^ the. Parallelogram (16, 17, 18) arranged The spring (24) presses on the test item (10) and that the action of the spring is adjusted one of its ends (25) is adjustable on one of the sides (16) of the parallelogram. 5. Machine according to claim 1, characterized in that the movement of the scanning roller (13) along the profile to be tested in an automatic manner by one or the other the other of two motors (27,46) can be controlled, the motors either being the drawing disk drive with the object if the resistance of this disk is less than a certain one Limit value, or drive the shaft (19) of the character rod (1) when the resistance of the Disc is greater than this value. 6. Machine according to claims 1 and 5, characterized in that it is provided with a stopping device (Fig. 11) which automatically engages during the drive of the shaft of the character rod when the resistance this wave exceeds a certain limit value, and that means (42, 51) are provided -are, through which the driving immediately after stopping in the opposite direction he follows. 7. ■ Machine according to claims 1 and 5, characterized by. a manual control box (5 °> 5 ³ O> which, when the drawing disc is driven by the motor (27), allows the speed of this motor to be reduced if the normal speed of this motor would result in an excessively high angular speed of the drawing staff and the drawing head. Considered publications:
German patent specifications No. 380153, 638283, 410. For this purpose 2 sheets of drawings © 609548/53 β. (609 726 12:56)