DE2133845A1 - Device for cross wire feed in a mesh welding machine - Google Patents

Description

Patent attorneys H. imSCHERLlCl ANIl

InIK-GoH

Vrer.na ^. KÖRBER MÖHCHEH 22, Sietnsdotfctr. 10 _{? # July ig? 1}

EVG development and collecting society m.b.H. In Graz

(Styria, Austria) Vinzenz-Muciiitsch-Str. 36

Patent application

Device for cross wire feed in a mesh welding machine

For electric mesh welding machines that use the spot welding method work, the line wires are usually pulled continuously from storage rings and in the longitudinal direction of the machine parallel to each other in a mutual distance corresponding to the desired longitudinal wire division of the grid Hehe of arranged transversely to the machine and to the line wire coulter Welding electrodes supplied, whereas the cross wires of the machine at a distance from the welding electrodes from the side, i.e. in the direction transverse to the longitudinal wire set. The already welded wire mesh together with the line wire array connected to it and the cross wire that is fed in are each pushed forward together in the machine until the wire crossing point is in alignment with the hehe of welding electrodes come lying down and the welding can be carried out

The feed of the welded wire mesh together with the line wire set and the fed cross wire by one cross wire »

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division as well as the intermittent actuation of the welding electrodes after this feed movement are usually of the Motor-driven main shaft of the machine derived, which makes one revolution with each work cycle of the machine and mostly also drives the device for the cross wire feed.

In a known device of this type, the transmission takes place the movement of the main shaft of the machine on the transport rollers, between which the cross wire is advanced by frictional engagement is, mechanically via a crank, a rack and a self-shifting gear, which the reciprocating Movement of the rack is converted into an intermittent rotary movement of the transport rollers, with a switching mechanism for this ensures that despite the reversal of the direction of movement of the rack when passing through the dead center position of the crank, the direction of rotation the transport rollers always remain the same · As it is in most In cases where it is desired to be able to feed cross wires of different lengths to the mesh welding machine, the drive crank is used designed with an adjustable crank radius.

In another known device for feeding the transverse wires two pairs of transport rollers are provided, which move in opposite directions depending on the movement of the drive crank. and carry out forward movements and of which a pair of transport rollers is always pressed against the cross wire under spring load while the other is lifted from the cross wire by a control mechanism against the pressure of the pressure spring «

The first disadvantage of all these devices is the difficulty of setting the different transverse wire lengths required for different width grids. The change in the radius of the drive crank is done by hand and requires the entire welding machine to be shut down. The crank pin mounted in a sliding guide is then "shifted" by means of a crank-driven spindle or the like. A scale can be provided on the guide of the crank pin and on the crank pin

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even a pointer can be mounted, which allows the set the desired cross wire length on the scale. The accuracy that can be achieved in this way is naturally limited.

Another limitation of the accuracy lies in the transmission. The claw clutches usually used in self-shifting transmissions work more precisely the smaller they are the claws are. It should now be noted that the cross wire is not only fed in, but also cut to length and out of the feed path must be removed before the next cross wire of the machine can be fed. These processes take a certain amount of time. Are the intended coupling claws small and act If the machine is running at high speed, there is no longer enough time readily available for these work processes. There are then quite complicated and expensive gears necessary in order to achieve an optimum of accuracy and on the one hand on the other hand, to achieve a sufficiently long switching time so that the operations described can be mastered.

The present invention relates to one for a mesh welding machine of the type described certain, novel device for cross wire feed, in which the cross wire material with the help is withdrawn from a wire ring intermittently by transport rollers and advanced in the direction transverse to the line wire array to then cut to length according to the desired cross wire length to ί will. It deals with the task of designing the device in such a way that that the achievable accuracy of the cross wire lengths can be increased significantly and that it is possible to use the machine to feed cross wires of different lengths quickly, preferably while the machine is running. This object is achieved according to the invention in such a way that the individual work cycles of the mesh welding machine controlling main shaft or an auxiliary shaft coupled with this a clock is arranged, which in each work cycle of the machine initially a to initiate the cross wire feed supplies the first clock signal by which the drive

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the transport rollers is switched on, that an actual value transmitter controlled by the transport rollers or by the advanced cross wire ^{material is provided for 1} the cross wire feed length, which triggers the shutdown of the transport rollers via an adjustable counting and control device when the target value of the cross wire feed length is reached, and that the clock generator after the end of the for the cross wire feed the maximum available time period 3e.of the working cycle supplies a second clock signal for resetting the counting and control device.

In this way it is achieved that each of the transport rollers advanced cross wire length not, as before, by the drive which transmits the feed force and is therefore subject to wear, but via an actual value counter and a control circuit including a control device is established which can be formed with high accuracy, wherein In addition, the control unit, if desired, during the course of the Machine can be set to a changed cross wire feed length.

As will be explained in more detail later, within the scope of the invention preferably electronic control circuits and hydraulic drive circuits for generating and regulating the feed movement of the cross wire used *

Embodiments of the invention are now referred to explained in more detail on the drawings.

The Pig, Λ to 3 show schematically the mechanical part each of an embodiment of a device according to the invention;

pig, 4 represents an exemplary embodiment of the electronic Control circuit of the devices according to the Pig, 1 to 3 represent

Pig. Figure 5 shows a detail of an electronic control circuit with several counters;

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6a and 6b show embodiments for actual value transmitters which are directly influenced by the cross wire material,

Fig. 7 is a diagram for explaining the cyclic control operations ·

In the device according to the invention shown schematically in FIG. 1, a hydraulic pump 3 is driven by the main shaft 1 of the mesh welding machine. The pump 3 conveys oil from a tank (not shown) into a pressure line in which a constant oil pressure is maintained by an adjustable throttle valve 6. The supply and discharge lines to and from the oil tank are labeled T » a

Via an oil filter 5 and an electro-hydraulic servo valve 7 the pump 3 can be set in operative connection with an oil motor 8 will. The oil motor 8 is able, via a back gear 9, to drive the transport rollers, which are coupled to one another by gearwheels 10, 10V 11, 11 ·, between which the transverse wire 12 by friction closure is advanced to set in rotation. The contact pressure exerted by the transport rollers on the cross wire can be achieved by means of an adjusting screw 13, which is only indicated schematically, can be regulated.

On the main shaft 1 of the machine, the eotor is also one e.g. photoelectric or inductive clock generator 2, (j which serves, in cooperation with a pulse generator 14 seated on the axis of the oil motor 8, which is part of a counting and Control device for the cross wire length is the electrohydraulic one Servo valve 7 to control. The nature of this control is in the Connection with FIGS. 4 and 5 will be explained in more detail.

In the embodiment according to 'Fig. 2, a shaft 25 is driven from the main shaft 1 of the mesh welding machine via a countershaft 18, which is arranged in alignment with a second shaft 26. The two aligned shafts 25 »26 can be connected to one another by a hydrostatic coupling 15 · On the shaft 26 is a hydraulically actuated, mechanically

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Niche brake 16 arranged with the-hydrostatic clutch 15 via an oil line 27, in which an electrohydraulic Servo valve 7 and an oil filter 5 are installed in connection stands.

If the electrohydraulic servo valve 7 is brought into such a position, as will be described later, that a connection is established between the hydrostatic clutch 15 and the brake 16, the hydrostatic clutch is activated in these two elements and in the line 27 by the conveying action of the driven rotor Oil pressure builds up until the pressure reaches the value set at the adjustable throttle valve 6. The brake 16, which is kept pulled by a spring in the idle state, is relieved of the action of the spring mentioned by a pressure piston and thereby released . At the same time, the housing of the hydrostatic clutch 15 is entrained by the pressurized oil, creating an operative connection from the main shaft 1 of the machine via the back gear 18, the shaft 25, the hydrostatic clutch 15, the shaft 26 and the back gear 9 to the Gearwheel, @ ffn 10, 10 · comes about, which _{drive the transport roller ^ 11 9} 11 '.

As soon as the electrohydraulic servo valve 7 is in a position is brought, in which das.vom the rotor of the hydrostatic Clutch 15 to drain oil delivered via line T to the tank can, the line 27 and all elements connected by it are depressurized. The spring provided in the brake 16 pulls the Brake on, and in the hydrostatic clutch 15 no more torques can be transmitted from the rotor to the housing.

All other elements, not mentioned here in more detail, which are provided with the same reference numerals as in FIG. 1, have the same function as in FIG. 1 and therefore do not require any further explanation here. It should only be mentioned that components are already commercially available which contain the hydrostatic clutch 15 and the brake 16 assembled. The use of such elements is of course also possible within the scope of the invention. However, for the sake of clarity

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a separate representation of both elements is given preference

In the embodiment of the invention shown in FIG. 3 is the process like the real connection between the main shaft 1 of the mesh welding machine and the transport rollers 11, 11 ' is, in principle the same as in the device according to FIG. 2. The difference between the embodiments according to the Fig. 2 and 3 is merely that, according to FIG. 3, both the Clutch 17 as well as brake 16 by spring pressure and oil pressure piston be actuated and that a hydraulic pump 3 is provided to generate the oil pressure, which is of a dedicated to 4 motor provided for this purpose, preferably an electric motor, is driven.

The electrohydraulic servo valve 7 controls the oil flow in such a way that that either the clutch 17 is applied via the line 30 or the brake 16 via the line 31 Element does not perform its proper function; so if the brake 16 is applied, it is released at the same time and the transport rollers can rotate freely; If the clutch 17 is acted upon, the operative connection between the Waves 25 and 26 interrupted.

To depending on the solenoid of the electrohydraulic Servo valve 7 supplied excitation current in later explained Way a variable throttling effect in the servo valve 7 to g achieve and thus ensure a smooth engagement or braking, are in the oil lines 30, 31 between the electrohydraulic Servo valve 7 "and clutch I7" resp. the brake 16 return lines 28 and 29 to the tank provided with throttles are provided, through which it is achieved that the electrohydraulic servo valve 7 is always traversed by flowing oil.

In Fig. 4 is schematically an example of an electronic Control circuit shown, with the help of which the length of the to be fed Cross wire can be adjusted. The clock generator 2 controlled by the main shaft 1 of the mesh welding machine is at a standstill via an amplifying AND gate 20 with the solenoid of the electrohydraulic ^ η servo valve 7 in connection.

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inductive or photoelectric clock generator 2 is the preferred way of doing this built up that he with each full revolution of the main shaft 1 within a certain angular sector of, for example 300 ° a pawn impulse, during the rest of the angle sector of 60 °, for example, does not emit a pulse. The V / ahl the size of the angular sector in which a pulse is emitted, depends on the largest required cross wire length that is fed should be, and the translation ratio between the Main shaft rotation and the rotation of the transport rollers. The leading edge of the continuous pulse forms the first clock signal, by which the drive of the transport rollers is switched on, and the trailing edge of this pulse forms the second Clock signal that causes the counter and control device to be reset.

In Pig. 7 is to illustrate this process on the The abscissa α plotted a full revolution of the main shaft 1, while an angular sector of 300 ° on the ordinate Continuous pulse T with a leading edge that detects the rotation of the main shaft FI and a trailing edge F2 is entered. The continuous impulse T opens the AND gate 20, so that the counting and control device 19, the electrohydraulic valve 7 via this gate in the Can operate the opening direction. Through the valve 7, the oil motor is switched on in the device according to FIG. 1 or in the case of the Devices according to FIGS. 2 and 3 via the hydrostatic or hydraulically actuated clutch an operative connection between the main shaft 1 and the transport rollers 11, 11 established; the transport rollers therefore begin to rotate, whereby the cross wire material is advanced, and begins at the same time the actual value transmitter, e.g. designed as a pulse transmitter, 14 pulses output, the time density of which is proportional to the feed rate.

The pulses emanating from the pulse generator 14 are counted in the counting and control device 19. The device 19 for its part now sends control voltages to the gate 20 at certain fixed counting points, whereby the excitation current at the solenoid of the servo valve 7 initially increases to a maximum value

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and then a descending course is given.

For example, the arrangement can be made so that according to 7 shows the excitation current E at the solenoid of the servo valve 7 is increased by one level after a certain number of pulses until it reaches its maximum value after a series of levels, in which the servo valve 7 is then fully open and the oil can flow through it with minimal resistance.

In the same way, the current reduction can be carried out according to the presetting of the counting and control device to a desired feed length done gradually so that the opening and closing of the servo valve and thus the onset and termination of the transport movement of the transport rollers 11, 11 'take place gradually, as can be seen from the diagram of FIG.

After reaching the preset number of pulses, accordingly the desired feed length, the Krreger current becomes the solenoid of the servo valve 7 in the gate 20 is completely interrupted.

The main shaft 1 of the machine now continues to rotate, the transport rollers 11, 11 · but stand still because now in the execution 1 shows the operative connection between the pump 3 and the oil motor 8 or in the embodiment according to FIGS. 2 and 5 the operative connection between the main shaft 1 and the transport rollers is interrupted. f

As soon as the main shaft 1 has rotated so far that the clock 2, the pulse output with the trailing edge F2 is terminated via a line 22 which connects the clock generator 2 with the counting and Control device 19 connects, the counter of device 19 is reset to Hull, so that a new counting process can begin can"

depending on the presetting of the counting and control device 19 can the current curve E in Fig. 7 extends over a small or large part of the length of the continuous pulse T, i.e. the length of the continuous pulse is decisive for the maximum feed length

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Should the actual value encoder 14- or the Counting and control device 19 with regard to the shutdown function of the feed fail after the desired feed length has been reached, at the end of the continuous pulse T from the clock generator 2 the feed is stopped because at the time of arrival of the trailing edge F2 of the continuous pulse T one of the two inputs of the AND gate 20 is dead. The servo valve 7 then interrupts the feed

Instead of the examples described here, Thought digital control circuits can of course also be used on analog-based circuits.

™ The pulse generator 14 can be directly connected to the drive means for the Transport rollers 11, 11 'be coupled, as shown in the Pig · 1 to 3 is shown, or it can, as indicated in Pig 6a, the cross wire between a measuring wheel 23 and a support roller 24 are passed through · In this case the measuring wheel and the support roller is taken along by the moving cross wire 12 and the pulse generator, which is coupled directly to the measuring system, sends accordingly the feed movement of the cross wire impulses.

In the modified embodiment according to FIG. 6b, measurements are taken of the actual value in the feed path of the cross wire material 12 is a magnetic one Recording head 32 and a magnetic reading head 33 provided at a predetermined distance a therefrom, these two Heads cooperate so that each time a magnetic signal mark is read from the cross wire by the read head 33 Counting signal is output to the counting and control device 19 and at the same time the recording of a new magnetic signal mark on the cross wire 12 is caused by the recording head 32. The reading head 33 then delivers after each feed of a piece of wire with the length a a counting pulse.

The two arrangements described last have the advantage that pulses are only emitted when the cross wire is actually moved "

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Instead of a single counting and control device 19 can also several designated in Fig. 5 with 19a, 19b and 19c are provided which can be individually and optionally connected to the pulse generator 14 through relays 21a, 21b, 21c. The production the connection can be made by hand using pushbuttons or automatically by a control mechanism. At this Arrangement can have any different number of pulses in each counting and control device, corresponding to a specific one Cross wire length, can be saved. With a mesh welding machine equipped in this way, it is possible to measure the length of the Cross wire according to a preset program or by pressing a button, according to the preset in the counting and control devices evaluate, change.

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Claims (12)

Patent claims: Λ, J device for the cross wire feed in a grid welding machine, in which the cross wire material is withdrawn intermittently from a wire ring with the help of transport rollers and advanced in the direction transverse to the longitudinal wire array, in order then to be cut to length according to the desired cross wire length, characterized in that A clock generator (2) is arranged on the main shaft (1) that controls the individual work cycles of the mesh welding machine or on an auxiliary shaft coupled to it, which in each work cycle of the machine initially supplies a first clock signal (F1) which is used to initiate the cross wire feed and which the drive uses (8; 15; 17) of the transport rollers (11, 11 ') is switched on so that one of the transport rollers or the advanced transverse . wire material controlled actual value transmitter (14; 23, 24; 32, 33) for the cross wire feed length is provided which, via an adjustable counting and control device (19), stops the transport rollers when the set value of the cross wire feed length is reached triggers, and that the clock generator (2) after the expiry of the maximum time available for the cross wire feed of each work cycle a second clock signal. (F2) for resetting the counting and control device (19) delivers. 2. Apparatus according to claim 1, characterized in that between the main shaft. (1) of the mesh welding machine and the transport rollers (11, 11 ") for the cross wire, hydraulically operated, controllable by means of an electrohydraulic servo valve (7) Drive or power transmission elements (3, 8; 15, 16; 3, 16, 17) are provided, the electrohydraulic servo valve (7) both as a function of the clock generator (2) arranged on the main shaft (1) and of the one that can be preset Counting and control device (19) can be controlled (Pig 1 to 3). 3. Device according to claims 1 and 2, characterized in that that one of the main shaft (1) of the mesh welding machine continuously driven oil pump (3) and one of this oil pump 20 9810/1092 Pump-fed oil motor (8) for driving the transport rollers (11, 11 ') for the cross wire (12) are provided, the electrohydraulic servo valve (7) between the oil pump (3) and the oil motor (8) is (Fig. 1). 4 _O device according to claims 1 and 2, characterized in that two aligned yokes (25, 26 ) are provided, between • which a hydrostatic clutch (15) or a hydraulically actuated clutch (17) is located, which is capable of establishing an effective connection between the two aligned 7 / ellen, or * to interrupt, that also on one (26 ) of the two cursing "tendency" .Teile between the hydrostatic clutch (15) or the hydraulically operated clutch (17) and the transport rollers (.11, 11 ') a hydraulically operated, mechanical brake (16) is provided which enables is to determine the transport rollers (11, 11 '), and that the oil pressure in the line (27) between the hydrostatic clutch (15) and the brake (16) or in the feed lines (30, 31) of the hydraulically actuated clutch ( 17) and the hydraulically actuated ba Ren brake (16) by means of the hydraulic servo valve (7) is so controllable that when an operative connection is established between the two shafts (25, 26) by means of the hydrostatic clutch (15) or the hydraulically actuated clutch (17), the brake ( 16). | released and, if this operative connection is interrupted, the brake is applied, 5. Apparatus according to claim 4, characterized in that in the feed lines (30, 31) of the hydraulically actuated Clutch (17) and the brake (16) an oil pump (3) driven by an additional motor (4) is located (Fig. 3). 6. Device according to one of claims 1 to 5 »thereby characterized in that the actual value transmitter (14) is a pulse transmitter whose pulse sequence corresponds to the feed speed of the cross wire material is proportional, and that the counting and control device (19) contains a counter which, when a predetermined 209810/1092 Counter reading a switch-off signal to the electro-hydraulic ^ servo valve "(7) outputs and in turn can be reset by a clock signal from the clock generator (2) (FIG. 4). 7. Apparatus according to claim 6, characterized in that in the excitation circuit of the electrohydraulic servo valve (7) there is an AND gate (20) to which on the one hand a clock (2), each of which supplies a continuous pulse (T), the front and back Trailing edge (FI ₁ F2) serve as clock signals, and on the other hand the Zäh.1- and control device (19) are connected. 8. Apparatus according to claim 7 »characterized in that the payment and control device (19) increases continuously or in steps to a maximum value and then decreases again from this value Control voltage (E) supplies to the AND gate (20). 9 «Device according to one of claims 6 to 8, characterized characterized in that the actual value transmitter (14), optionally by program control relays (21a, 21b, 2ic), to one of several Counting and control devices (19a, 19b, 19c) can be switched on, which are set to different cross wire feed lengths. ' 10. Device according to one of claims 1 to 9, characterized in that the actual value transmitter (14) with the transport rollers (11, 11 ') for the cross wire (12) for synchronous movement is coupled (Fig. 1 to 3). 11. Device according to one of claims 1 to 9, characterized ' characterized in that a measuring wheel (23) and a support roller (24-) are provided, which can be set in rotation through the cross wire passed between them (12), and that the actual value transmitter (14) is coupled to the measuring wheel (23) for synchronous movement (Fig. 6a and 6b). 12. Device according to one of claims 1 to 9, characterized in that for measuring the actual value in the feed path of the cross wire material (12) a magnetic recording 209810/1092 head (52) and at a predetermined distance therefrom a magnetic Read head (33) are provided, which cooperate so that each time a magnetic signal mark is read from the cross wire through the reading head (33) a counting signal to the counting and control device (19) and at the same time the recording of a new magnetic signal mark on the cross wire (12) is caused by the recording head (32). The patent attorney L.2.10.7ο ■ 209810/1092 Blank page