DE1254855B - Welding punch press, especially for thermoplastic plastics - Google Patents

Description

Welding punch press, especially for thermoplastic plastics The invention relates to a welding punch press, in particular for thermoplastic Plastic and similar materials that soften plastically at the welding temperature with hydraulic or pneumatic drive and electric lift control as well with attachment means to limit the stroke of the tool that is used to exert pressure, z. B. an electrode and at the same time provided with the punching tool, relative to Workpiece movable press link until the end of the welding process.

For welding of thermoplastics are predominantly Hydraulically or pneumatically operated presses are used because they are adjustable by their Pressure and thus also adjustable contact pressure for the pressing together of the welded parts before, during and after welding. Beyond that one strives when welding flat material such. B. thermoplastic plastic films or plates, etc., to cut through the welded material at the same time as the welding process, to cut or punch.

Various devices have been developed for this purpose. At the one is a combined welding and punching tool by means of a rotary table device used, with welding and punching tools performing their processing separately.

Another facility uses welding and stamping processes a combined tool from just one press, a so-called welding punch press, carried out.

The invention is in this last-mentioned machine combination applicable. It deals exclusively with the control of welding and punching machines.

The welding process by means of purely thermal heating devices or High frequency heating is well known. One subdivides the welding time in a heating season in which the material to be welded initially changes its solid state passes into a plastic state and in its further course the fusion of the two surfaces to be welded, and a cooling period during which the The weld metal is cooled down again so that the weld point is made after removal the welding press is solidified.

With smaller welding presses you have to specialize in the heating season Attach importance, especially when the material has softened, because the parts to be welded are pressed together under a given contact pressure Need to become.

If this pressure is generated hydraulically or pneumatically, so it is found that after the material has become dough, the pressing force remains unchanged is able to push the softened material away from the weld, what is usually not wanted. A pressure limiting device must therefore be provided which prevents the weld cross-section from being reduced too much.

To limit the contact pressure serving devices belong to the known prior art. The simplest way is to use spacer bars, which are placed on the table and on which the movable press part rests, This means that when the weld metal softens, this part penetrates deeper is avoided.

During the subsequent punching it is then necessary that these stops be removed again so that the punching can be carried out. Happened so far this removal by manual labor, resulting in a quick, continuous sweat and Excludes punching process.

In a device dealt with in German Auslegeschrift 1 114 630 for welding thermoplastic plastics is for that which carries the electrode Pressing member provided an adjustable stop screw with a toggle lock cooperates as a counter stop and is intended to prevent the weld metal from already is pushed away during the heating season by excessively high initial pressure the pressing of the welding tool into the still cold material is interrupted and only after the end of the heating season again made possible by the pressing member through the The stop screw and the toggle lock are locked during the heating-up time and the latter is unlocked by means of an electromagnet immediately after the start of the cooling period will. In this known device, the welding takes place in two stages, wherein the pressing member in the second stage after heating the The weld metal is only moved towards the weld metal so that the parts to be welded together is ensured. With this known device, d. H. however, no suggestion is given by this known welding device, how the stop mechanism of a welding punch press is to be designed in the the welding process is followed by a punching process.

The invention is based on the object of a welding punch press to create that does not suffer from the disadvantages of the known welding punch presses is, in particular the stop means previously used in welding and punching presses adherent disadvantage should be remedied.

To solve this problem, a welding punch press is proposed, which is characterized in that the stop means, which is known per se Way on the stationary or movable part of the press in the stop position are adjustable for the other part, are provided with a drive, by an electrical timer control of the movable press member is so controllable that it is before switching on or before the start of the punching stroke of this member the lifting gear is automatically removed from the stop position.

Preferably, at the same time as or through the welding stroke of the movable press member or its drive the timer, z. B. a time delay relay, set in motion after a predetermined, preferably adjustable Cooling period via a valve removing the lifting gear from the stop position and thus the release of the working piston under pressure for the Controls punching stroke. In the preferred embodiment of the invention the hydraulic or pneumatic drive cylinders for the working piston of the movable press member and the control piston of the stop means from a common Pressure source, e.g. B. a pump, controlled from a valve, its to the cylinder the control piston leading and serving for its extension into the stop position Connecting line to the working cylinder through a pressure valve of such a pressure setting what is blocked is that it is the line leading from it to this cylinder for the working stroke of the working piston only releases when the control piston is in contact with the stop means has reached its stop position. Such a control according to the invention is Applicable to all types of welding and punching presses, in particular both to bridge punching with several working cylinders as well as punching presses with a C-shaped stand and cantilever, movable press link. In both cases it does not matter whether the working cylinder or cylinders is located above the workpiece and in general Electrode and punching tool carrying press ram or press beam or the opposite Drive the work table so that it can be raised and lowered, and also for the arrangement of the lifting accessories it does not matter at which point between the movable and the stationary Press link attack them on these parts. In general, it is recommended that the sling outside of the combined welding and punching tool on fixed part of the press are arranged and by one or more control cylinders be brought into the working position and removed from this.

Because the pressure exertion and the end position of the pressure-exerting tool during the welding process on the consistency of the treated material, its Depending on the thickness and its softening properties, it is recommended according to the invention the lifting gear to different stop positions or welding strokes of the to make movable press member adjustable. Preferably there is the drive of the appropriately acting on the movable press part of the stop means from a hydraulic or pneumatic cylinder and a lifting device that supports this Piston with limited and possibly adjustable stroke.

However, since known means of stroke limitation are often complicated or not acting fast enough, the adjustable sling preferably consists from one on its drive part, z. B. Pistons, differently unscrewed Stop screw.

One embodiment of the invention is exemplified below for a bridge punch, namely Fig. 1 shows a cylinder of a welding punch press in section, and F i g. 2 a diagram of the electro-hydraulic control of the welding punch press.

The exemplary embodiment also applies analogously to a punch press only one cylinder for the working stroke as for a bridge punch press with two parallel cylinders for the working stroke.

A welding punch press that works according to this system is according to FIG. 1 a working cylinder in a stationary press body 1 by means of screws 3 2 attached. In this, the piston 4 moves, which at its lower end as Press ram can be formed if in a so-called C-shaped press about the working cylinder is arranged in the press stand and directly on an upper one movable press member acts. In the case of a bridge punch, on the other hand, the generally the piston rod of the piston 4 with the lower ends of at the corners of the press beam arranged tie rods connected and in the stationary press body 1 be arranged so that the stroke of the piston 4 down the described below Press bar 18 together with the welding and punching tools against the not shown, the press table underneath and carrying the workpiece is moved.

The cylinder 2 is fastened upwards by a screw 6. in its lower part designed as a cover 5 'stop cylinder 5 sealed. A thread for screwing in the pipe screw connections opens into its cylinder space 9 for supplying the hydraulic fluid to the hydraulic system. The hydraulic fluid then passes through a connection 7 and a bore 8 into the cylinder chamber 9 Acting on the cylinder on this side becomes the working stroke of the welding punch press carried out.

A further screw-in thread O is located independently of the line 7 in the upper part of the stop cylinder 5, which is in one, formed in this upper Cylinder space 11 opens. Lines 7 and 11 are two separate lines and not connected to each other. A piston moves in the upper cylinder space 12, which is held against the outer wall of the cylinder by a sleeve 13 sealed is. The connection of the cylinder space 11 is formed by a screw 15 attached Cover 14.

The piston 12 protrudes in its upper position when it is against the cover 14 strikes, a piece out of this with a cylindrical extension 12 '.

A stop screw 16 screwed into the piston 12 can be locked in position relative to the piston 12 by a lock nut 17 will. The head 16 'of the screw 16 rests against the press beam 18, which is with a part 18 'of the crosshead located outside of the welding and punching tools is firmly connected.

In the in F i g. 1, the piston 12 has moved through the pressure medium flowing into the line 10 and the pressure arm 11 to the cover 14 ajar, and the ram or press bar 18 is on the head 16 'of the screw 16 ajar, so that a deeper penetration of the electrodes into the weld metal than set by the stop screw 16 is prevented.

After the cooling period following the welding process has expired is, the punching should now take place and this is shown in Fig. 2 in a hydraulic circuit diagram symbolically shown multi-way valve 19 by running a not shown Timer for the cooling period controlled electromagnetically in position 19 a, so that the pressure medium from the cylinder chamber 11 via the connection 10 into the oil sump 20 can expire. This lowers the piston 12 with the stop screw below and gives the press ram resp.

Press bar 18 clears the way to carry out the punching. That the The pressure medium still acting on the cylinder chamber 9 now moves the press ram or the press bar further down to the lowest position, from which through not Means shown the switchover to the return stroke takes place.

The control for such a punch press takes place according to FIG. A Multi-way valve 21 with its switching positions a, b and c leads in the position 21 a that of a pump 22 via line 23 through the multi-way valve 19 and the line 24 pumped oil into an oil sump 35. The working piston 4 is located in its upper rest position. The line 26 to the annular space 25 of the cylinder is blocked.

To carry out the working stroke, consisting of welding stroke and punching stroke, the multi-way valves 19 and 21 are at the same time electromagnetically in the position b brought. As a result, in the multi-way valve 19, the one leading into an oil sump 20 Drain line interrupted, and the pressure medium passes through a line 23, the Valve 19 and a line 27 in the cylinder chamber 11 and pushes the piston 12 in which is the stop screw 16, up until the cylinder 12 on the cover 14 strikes. A bias valve 28 lets the flow of oil through only when through the The pressure setting ensures that the piston 12 is in the stop position moved up. Only then is the pressure medium via a line 29, check valve 30, line 31 passed into the multi-way valve 21, position b, so that via a line 33 the cylinder space 9 of the cylinder 2 is acted upon.

As already described above, the press ram or the press crosshead with the welding electrode so far down that on the one hand the welding can take place, on the other hand, after the punched material has softened further lowering of Press ram or press crosshead can not be done because the stop screw 16 prevents this.

Remain during the heating and cooling period to carry out the Weld the multi-way valves 19 and 21 in the position b. Is now the timer expired for the cooling period, the multi-way valve 19 is back in its position a moves. In this position, as already described above, the drainage takes place of the oil from the cylinder chamber 11 into the oil sump 20. At the same time, the pressure oil passed via the lines 23, 24, 31 to the multi-way valve 21, from where it is how previously pressurized on the cylinder chamber 9 via the line 33 for punching. As soon as the punching has been carried out, a limit switch (not shown) is activated in the lowermost punching position, the multi-way valve 21 is reversed into position 21c. Through this the flow of pressurized oil passes from line 31 into line 26 and acts on the Cylinder ring space 25, so that the press ram or the press beam is back again moved up to its starting position. In this starting position he has another, not shown, given via a limit switch control pulse that the multi-way valve 21 is moved into position 21 a. In this rest position is the Annular space 25 shut off so that the press ram or press beam rests on the oil column and thus maintains its position.

As already mentioned, the stop screw can be in its height position changed and adjusted so that the press ram according to the desired uniform weld seam strikes the screw or screws and thereby prevents the upper electrode from penetrating deeper into the softened weld metal.

Both the heating and cooling periods run according to the Control by a timer. When the welding process is finished, i. H. the If softened material becomes solid again, the punching takes place by the multi-way valve switched on and so that the working cylinder is acted upon again. Simultaneously receives the upper cylinder, which so far has the stop in its effective position has held, free drainage, so that the piston with the stop screw after moves down and gives the press ram free run to perform the punching.

After the welded part is separated from the waste by the punching has been, the ram or the press beam moves back into its upper rest position return.

Claims (7)

Claims: 1. Welding punch press, especially for thermoplastic Plastic and similar materials that soften plastically at the welding temperature with hydraulic or pneumatic drive and electric lift control as well with stop means to limit the stroke of the tool exerting pressure, z. B. an electrode, and at the same time provided with the punching tool, relative to Workpiece movable press member until the end of the welding process, thereby characterized in that the stop means '(16, 16') in a known manner on the stationary (1) or movable (18) part of the press in the stop position for the other part are adjustable, provided with a drive (10, 12) by an electric timer control of the movable press member (18) can be controlled in such a way that it can be switched on or before the start of the punching stroke Link the stop means (16, 16 ') automatically removed from the stop position. 2. Press according to claim 1, characterized in that the stop means (12, 16) to different stop positions or welding strokes of the movable Press member (18) are adjustable. 3. Press according to claim 1 or 2, characterized in that the Drive of the stop means acting on the other, preferably the movable press part (16) from a hydraulic or pneumatic cylinder (11) and this stop means bearing piston (12) with a limited, optionally adjustable stroke. 4. Press according to claim 2 or 3, characterized in that the adjustable stop means from one of its drive part (piston 12) different The stop screw (16) can be screwed out far. 5. Press, in particular bridge punch, according to claim 3 or 4, characterized characterized in that the drive cylinder (11) of the stop means (16, 16 ') in one Piece with a stop cylinder (5) of the working cylinder (9) of the piston drive of the movable press member (18) is formed. 6. Press according to one of claims 1 to 5, characterized in that that the hydraulic or pneumatic drive cylinder (9 or 11) for the working piston (4) of the movable press member (18) and the control piston (12) of the stop means (16, 16 ') from a common pressure medium source (pump 22) via a valve (19) are fed, its leading to the cylinder (11) of the control piston (12) and for its extension into the stop position serving connecting line (27) to Working cylinder (9) through an adjustable preload valve (28) such pressure setting is blocked that it leads from her to this cylinder line (29, 33) for the working stroke of the working piston (4) only releases when the control piston (12) has reached its stop position with the stop means (16, 16 '). 7. Press according to one of claims 1 to 6, characterized in that that simultaneously with or through the welding stroke of the movable press member (18) or its drive (4) the timer, z. B. Time delay relay in progress is set after a predetermined, preferably adjustable cooling period Via a valve (19) the lifting gear or its control piston (12) can be removed from the stop position and thus the release of the pressurized medium Controls working piston (4) for the punching stroke. Documents considered: German Auslegeschrift No. 1 114 630.