DE2242120A1 - DEVICE FOR PRECISELY POSITIONING OF PRESSES, IN PARTICULAR OF SLOTING MACHINES - Google Patents

Description

MASCHINENFABRIK WEINGARTEN A-G Weingarten, August 24th, 1972 '7987 WEINGARTEN

µ 72 224212C

Device for stopping presses with precise positioning, in particular grooving machines

The present invention relates to a device for stopping presses with precise positioning, in particular grooving machines for the production of grooved »sheets for sheet metal stacks of electrical machines, their clamping plates for the ones to be punched In the cycle of the ram stroke, the blank executes increments of rotation by an angle corresponding to the slot pitch, and to generate the incremental Rotary movement of the clamping plate one by one with a drive motor related crankshaft of the grooving machine driven indexing gear is provided.

In such grooving machines, the press ram is driven as well as that of the clamping plate for the blanks from the crankshaft, which is usually mounted in the lower part of the grooving machine. The continuous, revolving rotation of the crankshaft is used to drive the clamping plate through an interposed indexing gear in a step-by-step rotary movement of the Clamping plate converted. Each rotation of the crankshaft causes the clamping plate to rotate by one of the slot spacing angle of rotation corresponding to the blanks to be punched. The size of the angle of rotation is determined by means of a downstream indexing gear Change gear changeable.

The turning step of the clamping plate generated by the indexing gear starts shortly after the punching tool attached to the ram emerges from the grooved plate during the return stroke.

The end of the turning step results on the one hand from the requirement the ram at a sufficient distance from the one on the clamping plate shutdown the board in order to avoid difficulties in feeding and removing the board, and on the other hand, that with the ram stopped the step of rotation of the clamping plate has already ended, so that the large deviations that occur

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from the desired stopping point of the crankshaft due to uneven Braking has no effect on the position of the driver element of the clamping plate that engages in a marking on the plate to have.

The last-mentioned requirement arises because the unsutured '' Blanks are fed to the clamping plate in a precisely defined position must be so that the driver element properly in the corresponding marking on the board can intervene.

As soon as the turning step is finished, the support plate is locked in the direction of rotation by the indexing device, for as long as until the tool emerges from the board and a new rotation step of the support plate begins.

In relation to the position of the crankshaft, this means that the rotary movement of the clamping plate is approximately 60 ° after bottom dead center begins and ends about 60 ° after top dead center. The rotary feed movement of the clamping plate including the plate took place thus over an angular range of 180 ° in relation to the crankshaft. The crankshaft is stopped in the range of up to 80 ° after top dead center. Under these circumstances it was ensured that the shutdown of the slot punching machine would not take place until took place at a point in time at which the feed of the blank was carried out.

After completing one circuit board at a time, the crankshaft and thus also the press ram and the clamping plate stopped in order to remove the grooved and feed a to allow unslotted board.

The disadvantage of this design is that for a turning step of the clamping plate, only an angle of rotation of the crankshaft of 180 ° is available, which is enormous at high stroke rates large acceleration forces occur in the indexing gear.

In addition, it can happen that the tappet comes to a standstill late when the brake is worn and that the feed is flawless and removal of the board obstructed.

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To avoid these disadvantages, devices for stopping the crankshaft of a grooving machine have already been proposed (OS 1 552 595 and AS 1 627 269). Both versions have in common that the one deviates from the desired holding division Position of the idle partial shafts of the clamping plate for the blanks are rotated in this way by means of stops which correspond to a correspondingly designed counter surface of the sub-spindle that the deviation disappears.

However, both versions have the disadvantage that they have a rela-. tively require a lot of manufacturing effort and the parts are subject to considerable wear and tear. In addition, the AS 1 627 269 it happens again and again that production has to be interrupted because of a brake that needs to be readjusted. In the According to OS 1 552 595, turning the crankshaft is even impossible if the stop point deviates from the target position goes beyond a certain level.

In another known version (DL-PS 42 644) the crankshaft is stopped after the required work strokes have elapsed by means of two pulse generators rotating synchronously with the crankshaft. The disadvantage, however, is that the discs at a Changes in the number of strokes must be adjusted in each case in order to take account of the changed run-out path of the crankshaft. In addition, there is no possibility of minor variations in the holding position of the crankshaft from to correct the desired stop position afterwards, which is an indispensable prerequisite for the correct discarding the board to be punched is on the clamping plate.

The object of the present invention is to provide a device for to provide precise stopping of the clamping plate for blanks in grooving machines, with the simplest way and Any large deviations of the holding position of the clamping plate from a required position without the use of wearing parts can be made to disappear.

This object is achieved in that as a drive motor for. the slot punching machine is a known direct current pancake motor is arranged, and that the disc motor at

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stopped crankshaft depending on its position in relation controllable to a predetermined angular position in a direction of rotation which causes a possible angular deviation to disappear is.

An embodiment of the invention is characterized by two at a distance from one another in the vicinity of the action of the web one synchronized with the crankshaft revolving Nooke arranged contactless encoder and another contactless encoder, which is close to the action Track of a cam rotating synchronously with the clamping plate ' is.

It is advantageous according to the invention that the donors included angle related to the axis of rotation of the cam disk is at least equal to the angle by the amount of which the stop point the crankshaft scatters when stopped at top dead center.

It is also proposed by the invention that the control area formed by the cam extends so far in the circumferential direction of the Cam disc extends that only when the crankshaft is in the correct position are both sensors damped, and that the sensors are linked to one another via a logic circuit which has three contactors, one of which is the further puncture process of the grooving machine controls, and the other two each cause one direction of rotation of the pancake motor.

Another Formation of the invention proposed that a potentiometer is provided for adjusting the number of strokes of the plunger, which with is mechanically coupled to a further potentiometer which is connected to the timing element.

Another great advantage of the invention is that the pancake motor is coupled directly to the crankshaft.

The advantages that can be achieved with the invention are that the feed area for one rotary step of the clamping plate extends over a larger part of the crankshaft revolution can. By increasing the time available for a rotary step, even those with high stroke rates of the

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Groove punching machine considerable acceleration forces considerably be reduced. In addition, the number of ram strokes can be infinitely varied between a minimum and maximum value can be set quickly and precisely, with the mechanical coupling of the potentiometer for setting the stroke rate with another potentiometer ensures that the stopping point of the crankshaft is as accurate as possible is adhered to. This motor has an extremely small rotating mass and has a very constant start-stop behavior so that hardly any major "deviations of the crankshaft from the required holding position can occur and thus the the previously used separate brake and clutch can be omitted.

It is now also possible to set the stopping point of the crankshaft in to relocate the top dead center of the slide movement, with the space required for transporting the board between The ram and clamping plate are additionally enlarged.

It is also possible to set up the grooving machine in the To carry out slow speed.

The invention is in the following to / hand a drawing that shows a represents any embodiment, explained in more detail.

Show it:

B'ig. 1 an automatic groove punching machine

Fig. 2 is a partial side view of the grooving machine on average

Fig. 3 shows the sequence of the punching and turning step period, pulled on one turn of the crankshaft

Fig. 4 shows the position of the cam disk when it is correct Shutdown of the crankshaft

Fig. 5 shows the position of the cam disk when it is too weak Burning of the crankshaft

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Pig. 6 the position of the cam disc when the crankshaft is braked too hard

. Pig. 7 different punctures on the according to the invention equipped grooving machine during the Manufacture of a circuit board

8 shows the electrical circuit diagram for the inventive Furnishings.

In the grooving machine shown in FIGS. 1 and 2, 1 denotes a transport device which has holding arms 1 a for the blanks 2. 3 denotes the clamping plate on which the blanks 2 are placed by the transport device 1. The spindle 4 of the clamping plate 3 is connected to the crankshaft 7 via a change gear 5 and an indexing gear 6 on its underside a cam 5b, in the vicinity of which a contactless encoder 8 is arranged. Another in sync with. of the crankshaft 7 rotating cam 11 carries a spanning about 90 ° extending cam 11a in the web near two likewise arranged in this embodiment, offset by 90 ° encoder 9 ^nd 10th The length of the cam 11a in the circumferential direction of the cam disk 11 is dimensioned such that when the cam disk 11 is in the correct position, both transmitters 9 and 10 are damped. The extension of the cam 11a in the circumferential direction of the cam disk 11 can of course be selected. It is only necessary to set the angular spacing of the encoders 9 ^and 10 from one another accordingly.

The ram 12 of the slot punching machine is driven directly by a DC-operated disc motor 13 coupled crankshaft 7 via a linkage 14 with rocker arm 15 on the connecting rod 16.

The mode of operation of the device according to the invention is described below using the sequence of the grooving process of a board.

At the beginning of the work cycle, the plunger 17 is in its upper position

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Dead center stopped. The clamping plate 3 with the driver element (not shown) for the board 2 is in a precisely predetermined position so that the board 2 that has just been grooved is received by the holding arms la of the transport device 1, transported to the next station, not shown for the sake of simplicity, and stored there can. Another holding arm of the transport device 1 simultaneously conveys a blank 2, which has not yet been grooved, from an alignment station, also not shown, over the clamping plate 3 and lowers it onto it. In the alignment station, the board 2 was aligned by means of a marking, for example a hole punched in it, in such a way that the marking always assumes the same position in relation to the clamping plate 3 when the board 2 is put down. The holding position of the clamping plate 3 is chosen so that its driver element is precisely aligned with the marking in the board and can engage in it. After the board has been clamped onto the clamping plate 3, the pancake motor 13, which is operated with direct current, receives a start signal. The start-up process that now takes place, but also the braking process, can be influenced by limiting the motor current.

Since the clamping plate 3 and the ram 12 of the grooving machine are in mechanical connection with the crankshaft 7, each revolution of the crankshaft 7 causes a stroke of the tappet 12 and. a step of rotation of the mounting plate 3 by an angle equal to the Slot pitch of the board 2 to be sloted corresponds. The size of the The rotary step was previously set via the change gear 5 been.

As can be seen from FIG. 3, a turning step begins shortly after the tool attached to the ram 12 emerges from the groove punched in the plate 2. Because of the positionally precise shutdown of the clamping plate 3 which is possible by the device according to the invention, the duration of a rotary step of the clamping plate 3 can now be extended until shortly before the tool hits the blank 2. The size of the turning step resulting here is approximately 270 °. The beginning of the rotary step is determined by position A of the crankshaft 7, the end of the rotary step by position B. The angular range BA of the crankshaft J in which the clamping plate 3 is stopped,

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is therefore still 90 and is sufficient for perfect punching of the grooves in the board 2 to allow.

In the embodiment to be described here, the pancake motor was 13 has been started when the plunger 12 is in the upper Dead center and the turning step to be performed was halfway through. It follows from this that the After completion of a plate 2, crankshaft 7 must be carried out as close as possible to the desired stopping point, otherwise the driver element of the clamping plate 3 not with the The marking in the board 2 is aligned, which means that proper grooving of the board 2 is not possible.

After all the grooves have been punched into the blank 2 lying on the clamping plate 3, which continues to rotate step by step, ■ the clamping plate 3. » apart from the last half turning step, rotated by 360 ⁰ . The tool emerges from the last punched groove and the crankshaft 7 now has to be stopped again in order to enable the finished board 2 to be removed and a new board 2 to be fed in.

The switch-off signal required for this for the pancake motor I3 supplies the contactless encoder 8, namely when it by the Nooke 5b rotating synchronously with the clamping plate 3 is damped on the change gear 5a. Because the braking angle of the disc motor 13 depends on the number of strokes set, but the crankshaft 7 is as precisely as possible regardless of the number of strokes the desired stop position is to be stopped, the cam 5b is arranged so that the switch-off signal is so early is supplied that a shutdown of the crankshaft 7 is possible even at the maximum number of strokes in the desired position. So that the crankshaft 7 is not stopped accordingly earlier at lower stroke rates, which is at least a certain amount Loss of time in the correction of your holding position, described later, is possible with the potentiometer l8 for the setting the number of strokes of the grooving machine, a further potentiometer 19 is coupled, which enables the switching on of the timing element 20 Signal to contactor 21 initiated at the right time. Despite the pending shutdown signal for the pancake motor I3 is only switched off when

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if its braking torque is sufficient., the crankshaft 7 in the desired Stop the holding position.

Immediately after the crankshaft 7 has stopped, the contactless sensors 9 and 10 check whether the desired Holding position of the crankshaft 7 has been adhered to exactly ".

That's the case when, as in Pig. 4, both encoders 9 and 10 are attenuated by the Nooke 11a. Then the board 2 taken up by the holding arms la of the transport device 1 and, as already stated, transported away.

However, if the holding position of the crankshaft 7 deviates from the desired holding position for any reason, a correction process takes place immediately after the crankshaft 7 is stopped, in which the pancake motor 1J> starts at slow speed at a reduced speed and the direction of rotation is controlled in this way becomes that the deviation disappears. The speed of the pancake motor 13 operated at creep speed is set by means of potentiometers 24 and 25.

There is a deviation in the holding position of the crankshaft 7 in individual cases results from either too weak or too strong braking of the moving machine parts, must therefore first the direction of the deviation can be determined to the disc armature motor 13 in the required to achieve the desired effect. der.liehe direction of rotation to be able to control. Take on this task the contactless encoders 9 and 10.. ■

In Pig. 5 shows the position of the Nooke Ha and thus of the crankshaft 7 in relation to these two contactless transmitters 9 and 10 when the braking is too weak. As can be seen, the transmitter 9 is undamped in the operating direction of rotation of the crankshaft 7 assumed in the direction of the arrow YJ.

In contrast, FIG. 6 shows the position of the Nooke Ha when it is too strong Braking the crankshaft 7 · The Nooke Ha is located here not yet in the active position to the encoder 10. As a result, this is still undamped.

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From Fig. 5 and 6 it can be seen that the transmitter 9 and 10 depending on the direction the deviation of the crankshaft 7 from the desired holding position have a certain switching state. This switching state is linked in this exemplary embodiment AND elements existing control according to FIG Correction in the operating direction of rotation of the pancake motor 13 (positive correction) and if the braking is too weak via the * Contactor 23 makes a correction in the opposite direction (negative correction).

Contacts 21a, 22a are used to control the pancake motor I3 and 23a of the contactors 21, 22 and 23 at corresponding points of the Arranged circuit.

When the deviation disappears, both encoders 9 and 10 are damped, as a result of which the pancake motor I3 is switched off the slow speed is effected. The maximum remaining breakpoint error that can be achieved during this braking process in relation to the desired one Holding position is + _ 0.5 °. Should be before the correction occurring deviation be so large that neither of the two transmitters 9 and 10 is damped by the Nooke 11a, then takes place Correction as long as immediately after the pancake motor 13 has been switched off in its indicated by the arrow 17 Operating direction of rotation until both encoders 9 and 10 are dampened.

In Fig. 7 the most important functions of the invention are Groove punching machine applied during the manufacture of a plate 2.

The circuit shown in Fig. 8 also ensures that that the grooving machine cannot be switched on or that the transport device does not have a new plate 2 on the clamping plate 3 can be stored, provided that both encoders 9 and 10 are not attenuated.

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Claims (1)

224212Q Claims l.y device for stopping presses with precise positioning, in particular of grooving machines for the production of grooved sheets for sheet metal stacks from electrical machines, their clamping plates for the blank to be punched, executes rotary steps in the cycle of the ram stroke by an angle corresponding to the slot pitch, - and for generating the step-by-step rotary movement of the clamping plate one driven by the crankshaft of the grooving machine connected to a drive motor Indexing gear is provided, characterized,· : that as a drive motor for the grooving machine a per se known direct current pancake motor (lj5) is arranged, and that the pancake motor (13) when stopped Crankshaft (7) depending on its position in relation to a predetermined angular position in .ein a possible Winkelab The direction of rotation that makes it disappear is controllable 2. Device according to claim 1, characterized by two at a distance from one another in the vicinity of the path of a rotating synchronously with the crankshaft (7) Nooke (lla) arranged contactless encoder (9,10) and a further contactless encoder (8), which is in the vicinity of the web a cam rotating synchronously with the clamping plate (3 ") (5a) is arranged. 3 »Device according to claims 1 and 2, characterized in that the angle enclosed by the encoders (9, 10) is related on the axis of rotation of the cam disk (lla) is at least equal to the angle by whose amount the stop point of the crankshaft (7) scatters when stopping at top dead center. K. Device according to claims 1 to 5, characterized in that the control area formed by the cam (11a) is -2- ■ 409809/0809 world extends in the circumferential direction of the cam disc (11) that only when the stopped crankshaft (7) is in the correct position are both senders (9,10) damped. 5. Device according to claims 2 to 4, characterized in that that the donors (8,9,10) are linked to one another via a logic circuit. 6. Device according to claim 5 *
characterized in that the logic circuit J has contactors (21, 22, 25), one of which (21) controls the further puncturing sequence of the grooving machine, and the other two (22, 23) each have one direction of rotation of the pancake motor (13) cause. 7. Device according to claims 1 to 6, characterized in that that a potentiometer (18) is provided for adjusting the number of strokes of the plunger (12), which with a further potentiometer (19) is mechanically coupled, which is connected to the timing element (20). 8. Device according to claim 1,
characterized in that the pulley motor (I3) connects directly to the crankshaft (7) is coupled. k 0 9 8 ü β! Ο 'B 0 Ϊ «J Blank page