DE1752745A1 - Device for deep drawing of seamless containers closed at one end - Google Patents

Description

The invention relates to a device for deep-drawing seamless containers closed at one end.

In particular, the invention relates to a fluid operated system for a deep drawing device, which ensures precise control of the stroke of a reciprocating piston during the entire working time is. This precise and reliable control of the stroke of the reciprocating piston is particularly important Meaning, because at least one drawing punch is attached to each of the two opposite sides of the piston, so that a movement of the piston in one direction or the other represents a working stroke and at least one container generated in this way on each stroke. In addition, the device should strokes in a number of 120 to 160 per minute

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Hannovtr 43400 · Comnwrzbank Haanww VHKB · Otmamr loafc Hannover 10 »4M · DwHdK Bank Hannover 7/1« 05

execute what the problem of uniform control and Dimensioning of the stroke of the driving piston in both directions only clarified. This lift control device or control must not only be essentially instantaneous, but also in a relatively smooth, pliable manner Art, because the thickness of the container wall during the deep-drawing process is very small, for example on the order of about 0.152 mm. If there is excessive jolting or shaking of the Splitting the device dsbif occurs, the entire pulling process seriously in! rage.

Various methods have been proposed, such as that disclosed in U.S. Patent 3,167,044 is described in which a fluid operated device Manufactures container by pulling and there is a piston which has a drawing punch at the opposite end wearing. A piston driven by a crank, which is located in a fluid circuit and which is used to drive a reciprocating piston has been described in U.S. Patent 2,766,590. A! Fluid coupling is also described in U.S. Patent 3,314,274. Until now, however, the earlier practice of deep drawing is still not with a drive piston, which constantly moves a piston back and forth, the drawing punch on its opposite ends has been combined with a reliable lift control device, with an instant correction of a

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unbalanced stroke of the drawing punch is created relative to the drive piston. The drive system according to the US patent 3 167 044, which works completely hydraulically, speaks relatively slowly and has all the problems of the leakage fluid that occurs. If a drive piston of the type described in US Pat. No. 2,766,590 into a hydraulic circuit with a drive piston therein is used for the drawing punches, as shown for example in US Pat. No. 3,167,044, additional ones result Problems because the rapid reciprocating motion of the drive piston can encourage an unbalanced stroke, but one Correction in such a device must be effective immediately and reliably, but also smoothly.

The object of the \ ^r orliegenden invention is to provide an improved pull-up device in which an accurate Hubbemessung of the drawing punch on opposite ends of a common drive piston by a reliable and smooth operating control of the stroke of the common! Drive piston is guaranteed at all times and thereby a too large or too small stroke of the drawing punch is prevented. The device always works in a constant, repeatedly self-correcting manner.

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This is achieved in that a closed hydraulic circuit is provided, in one branch of which there is a piston and in its other branch a yoke that moves back and forth is arranged is, whereby with the mediation of the fluid, the piston is reciprocable, which is on both sides with a piston rod is provided, which carries drawing punch, and that with each side of the hydraulic circuit on both sides of the piston a control container connected, the fluid in that part of the hydraulic circuit feeds, in which there is a lack of fluid, which indicates and triggers a change in the stroke of the piston.

An embodiment of the invention is referred to explained in more detail on the drawing.

In the drawing show:

Fig. 1 is a schematic view of an overall control system for a device as disclosed in US Pat. No. 3,167,044 as prior art is shown

FIGS. 2 and 2a are schematic views of a hydraulic drive and control system according to FIG present invention using a tandem pulling device and

3 shows a section through a check valve,

which is used in the hydraulic circuit of the present invention.

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As already mentioned above, the well-known tax system, as described in U.S. Patent 3,167,044, improved by the present invention. The description of the hydraulic The circle of this US patent is brief but sufficient to show the problems encountered with such a system and the features and advantages of the present invention, for which reference is first made to FIG. 1 of the drawing, to highlight.

The device according to the above-mentioned US patent consists of a housing 2, which is closed at both ends by appropriate closures 4. Each closure 4 has a central opening 6, which is connected to an en-feprechenden Similar opening 8 is aligned in the end of a cap 10 of a cylinder in which a piston 14 is mounted. At opposite Piston rods 16 are attached to the sides of piston 14, the ends of which carry drawing punches 18. Each drawing punch 18 moves through the corresponding tool assemblies, such as hold-down devices, drawing dies, etc., which are designated by 20. The tools 20 contain, as disclosed in the above-mentioned US patent, a shape 22 with which the shape and the curvature of the bottom of a container is formed when the drawing process by the drawing punch 18 comes to an end and the workpiece or the container has been driven through the tools 20 and emerges from them again. At this bottom shape 1st a border so holder 3 LS attached. The other bottom shape carries the limit switch 4 LS. These switches kick the floor

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of the container together, so that a switchover of the anti-piston piston 14 takes place. The opposite sides of the cylinder 12 are provided with openings 24 and 26, and a line 28 leads to the opening 24 and a line 30 to the opening 26. The line 28 is connected to the opening 32 of a four-way valve and the line 30 to the Opening 34 of the same valve 33. This valve also contains an opening 36 which is connected to a line 28 which leads to a pump 40, and an opening 42 which is connected to a line 44 which leads directly to a reservoir 46. This four-way valve is conventionally controlled in the US patent by opposing air operated valves 48 and 50 which, in turn, are controlled by limit switches 3 LS and 4 LS located to the right and left of the drawing tools. If a main switch of the main circuit is switched on, the pump 40 conveys a fluid through the line 38. If the fertilizer 33 is in the neutral position, the openings 36 and 42 are connected via the line 52 of the valve 33. In this position the device is ineffective and the pump only pumps the Fluidura out of the reservoir 46 and back again via the line 44. If the valve 33 is actuated by appropriate means so that the openings 36 and 32 are connected by the valve line 54, the fluid flows from the pump 40 via the line 38, opening 36 and line 54 into the line 28 and then neon left to the left side of the piston 14,

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while on the same side ΐ'Iu i dura aur. the opposite space of the cylinder 12 through the opening 26, line 30, opening 34 of the valve 33, through the valve line 56, opening 42 and line flows back into the reservoir 4o. All of this is accomplished by air valves 48 and 50 in a manner analogous to that described in the referenced patent. When the system is switched to automatic operation and the piston 14 ends its stroke on the right, the limit switch 4LS is actuated, which in turn actuates the air valve 50, specifically because the valve line 53 in connection with the openings 3- ' and Ao the valve 32 is brought, while the valve 60 in line Va ⁿ binöung with the jffnungen 32 and is brought 42nd As a result, the piston 14 now moves in the opposite direction. The air valve 48 can now also be actuated roughly. As a result, the pump -10 will demand a fluid to the valve line 58 via the line 30 and the line 30 to the right side of the cylinder 12, while at the same time fluid from the left half of the cylinder 12 via the line 28, valve 33, valve line 60, line 44 flows into the reservoir 46 until the piston 14 has completed its full stroke to the left and the bottom of the deep-drawn container in the left die of the tool package 20 touches the left bottom mold 22 and thus actuates the limit switch 3 LS, which in turn actuates the air valve 43 operated, which switches the spindle of the valve 38 into such a position that the opening 34 of the valve 33 is now connected again to the lines 28 and 38 and the valve

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line 56 with lines 30 and 44. Now is the air valve 50 is set so that actuation of the spindle of the valve 33 is enabled. This automatic way of working works continues as long as the entire device is working.

From the above description it can be seen that the actuation of the valve 33 via the air actuated valves 48 and 50 takes place, and that the latter in turn by the limit switches 3LS and 4LS, which are in the tool assembly 20 the pulling device are controlled. The limit switches 3LS and 4LS do not respond particularly quickly to any inaccuracies in the stroke of the piston 14, which depends on their position and the way in which they control valve 33 is due. In addition, the entire control system is designed so that corrections for the strokes in a simple manner and primarily by virtue of the fact that the pump 40 is effected and therefore not so quickly and so go smoothly as it would be possible. A quick correction is in a device of the type in question, with Stroke rates of 160 works per minute are necessary. For this reason, the device for self-correcting the stroke of the Work stamp immediately and with extraordinary accuracy, Suppleness and reliability.

A preferred embodiment of the present invention is shown in FIG. 2 and comprises a housing 70, in FIG in which a drive machine 72 is mounted, which comprises a crankshaft 74. The crankshaft 74 is made up of stub shafts 78

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and crank webs 76 together, between which a crank pin lies and is mounted in suitable bearings. The crankshaft is driven by a wheel 80 in a known manner. When the drive wheel rotates, the crankshaft 74 moves, which lies with the crank pin in a sliding block 82, which moves up and down in a slot 83 and moves the yoke 84 back and forth, alternately afterwards left and right so that the left and right pistons 85 and 86, respectively, also reciprocate. During the reciprocating movement of these pistons, the fluid in the chambers 90 and 92 acts on opposite sides of a drive piston 94, which lies in a cavity 71 of an elongated cylinder 95. Piston rods 96 are attached to the drive piston 94 on opposite sides, at the ends of which one or more drawing punches 98 are attached. The fluid in the cavity 71 and in the chambers 90 and 92 forms a common fluid circuit, the piston 94 lying in one branch of the circle and the yoke 84 in another branch. The drawing stems 98 take the workpiece to be drawn in the shape of a cup with them through a die stack 250, which can be composed of several dies.

The chambers 90 and 92 are provided with an overload line 99, which contains Riiok3chlagventile 100, so that these Overload line with the chambers 90 and 92 can be brought into connection. These valve assemblies work as follows, for which purpose

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Reference is made to Figures 2 and 3 of the drawings. It is assumed that the drive piston 94 to the right has been moved and there is a foreign body in the right die stack that is subject to movement of the associated Opposite drawing punch 98. Becomes the front end of the draw pile impaired by such a foreign body, the i ^ uidumssdruck rises in the left ventricle 90 on the left side of the drive piston 94 very strongly, whereby a force on the part 101 of the finger 101 'of the left Valve arrangement 100 is generated, which is greater than the force that is exerted by an air pressure of the air line 103, the wants to keep the left valve 100 in the closed position and the z. B. set to 1.97, ie approximately equal to 2 kg per cm is. The air line 103 is with a bore 200 at the small end of the housing 201 of the check valve design connected (Fig. 3). Air in line 103 flows through chamber 202 into valve housing 201. When the hollow plunger 101 'is in the extended position shown, is the bore 203 in the shaft 204 of the plunger in communication with the space 205 of the housing 201, so that air is free in can flow into the space 205 and can hold the plunger 101 of the valve assembly 100 in the extended position. V ^ enn der Fluid pressure in the chamber 90 but exceeds the air pressure in the line 103, the plunger 101 'is pushed back and the Hole 203 exposed to atmosphere. Of the

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Plunger 101 "remains in this retracted position as long as until he manually duv'cb the operator again becomes, which is done by the fact that the handle 206 detected and the, shaft 204 is pressed inward, so that the Bore 203 in the shaft 204 again with the small chamber 202 is in communication in the housing.

'. When the left valve assembly 100 opens, runs Fluidurn from the chamber 90 via the bypass line 99'ab, ', so that the right valve arrangement 200 also opens, so that Pluidum from chamber 92 also expires. Both valve arrangements 100 now remain open until they are readjusted and allowed by the operator the outflow of I'luidum from chambers 90 and 92 into the Bypass line 99, which means that the IMuidum is about the Bypass line is reciprocated instead of acting on the drive piston 94. When the pressure on the drive piston 94 disappears, it remains there until the fault has been eliminated. The right valve 100 operates in similarly if a malfunction occurs on the left drawing die. Using a bypass line to the Short-circuiting the two fluid chambers prevents damage on the machine or its other facilities.

Bgi the back and forth movement of the drive piston 94 to the left and to the right is at least one drawing punch 98 and a Yferlsfcück moved through associated drawing dies

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and a drawing operation is carried out. When carrying out drawing operations, it must always be precise and uniform Stroke length of each drawing piston take place, so that containers are created by the drawing process, which are uniform Distinguish quality. When a plurality of drawing dies are attached to each piston rod 96, this problem becomes even more complicated if there is an uneven stroke of the piston 94 in one direction or the other occurs.

Uneven strokes of the drive piston 94 and the The larger or smaller strokes of the drawing punches 98 which result from this are reduced by the present invention in the following corrected automatically.

A pump 110, which is driven by a motor 110 ^f , pumps a hydraulic fluid, for example oil, at low pressure, for example 2.8 kg / cm, from a container or reservoir essentially continuously through a main line 112 and through branch lines 114 of the crankshaft 74. The line 112 also branches off to the bearings for the stub shafts 78 of the crankshaft via the branch line 116, in which a pressure regulating valve 116 'is contained and from which branch lines 118 emanate. These lines are used to lubricate all bearings.

Fluid from the tank also flows from the pump 1'Ό via branch lines 120 and 121 via a number of check valves 122 and 124 in line 120, 123 and 125 in

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the line 121 to the lower ends of the chambers 90 and 92 as well as to regulating tanks 126 and 126 ', which are connected in the lines 120 and 121 between the different check valves and 124 and 123 and 125, respectively. These volume regulating containers 126 and 126 ′ contain a piston 128 acted upon by air, which acts against the fluid in each of the containers 126 and 126 ′, and. the eluid is kept at a pressure of 2.8 kg / cm by means of the pump 110. The fluid in lines 120 and 121 presses pistons 128 in chambers 126 and 126 into their retracted position. Each chamber 126 and 126 'is connected to a three-way solenoid air valve 130 via lines 132 and 133, while the valve 130 is in turn connected to a main compressed air line 103 ¹ by line 135. The lines 121 and 120 are also connected to branch lines 136, 137 and 138, of which the line 136 contains check valves 139 and 140 that counteract one another. The operation of the valve 130 is controlled at the right time via the micro-limit switches LS1 and LS3, which are arranged at opposite ends of the machine. One of these switches is switched by the switch contact X on a certain drawing punch 98 when the stroke increases, which indicates a corresponding disturbance in the stroke or in the total movement path of the piston 94 in one case

Direction can be traced back and causes the desired Shift the valve as follows.

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When ζ, B. the drive piston 94 executes a stroke to the left, which is greater. than in Pig. As shown in FIG. 2, v / eil fluid escapes from the chamber 90, the microswitch IS3 is actuated by (for the associated switching contact X on a right drawing punch 98, because an unbalanced stroke of the drive piston 94 takes place relative to the stroke of the yoke 84. When this occurs , the limit switch LS3 closes (see Pig. 2 and 2a) and energizes the relay Rp, which then _{closes the contacts R 2} in the glue for the solenoid 2, while the contacts R "

create a hold circuit for the relay Rp. Y ^T is supplied hen the solenoid 2 with current, it immediately moves the spindle of valve 130, so that the apertures A and C are connected to each other so that air from the line 135 at a higher pressure,

2

for example, 5.6 kg / cm than the low pressure of 2.8 kg / cm in the hydraulic lines 112 z. B. can act on the piston 128 in the volume rain! Container 126 so that

this against the pressure of 2.8 kg / cm "of the pluid in the bed
^w holder 126 can move. The result of this is that essentially all of the pluid from the container 126 is pressed via the line 120 past the valve 124 into the chamber 90 until the loss of pluid in this chamber via the line 138 is compensated for again. The pluid in line 138 then opens valve 190 and allows excess pluid to drain through valve 140 via line 160

ο with a pressure that is above the pressure of 2.8 kg / cm and

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also through the line 112 into the bearings of the drive machine 72 and back to the container. It can also be seen that during the escape of the fluid from the cylinder 126 at an increased pressure, the check valves 122 and 123 are held in the closed position by this fluid pressure, the more so as the pressure of the fluid in the container is almost zero When the piston rod of piston 128 reaches the end of its stroke, it will detect a closed limit switch LS2 and open it and thus also a conductor which leads \ A to relay R _n . When the relay Rp opens, the solenoid 2 is de-energized and the valve 130 returns to its neutral position, whereby all parts are blocked and the 3? Luidum continues through the lines 120 with approximately

2.8 kg / cm pressure flows through, so that the piston 128 in the Longer 126 is returned and the chamber by the pump 1 "O fills again, so that the G-leioh__weight in the entire hydraulic system is restored.

Conversely, if an excessive stroke of the piston 94 to the right occurs, the limit switch LS1 is acted upon by the switching contact X on one of the left drawing punch 98 and the switch is closed. When the switch LS1 closes, it supplies the relay R ₁ with current, so that the contacts R. in the hold circuit close and the contacts R. in the line of the solenoid 1 * The movement of the solenoid 1 causes a displacement of the spindle of the Valve 130, whereby the valve

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Openings B and C are connected to each other. Air can now flow into the volume control chamber 126 and cause the piston 128 to move so that the fluid can flow from the chamber 126 in the line 121 past the valve 125 up into the chamber 92 until the fluid in it Chamber is completed again. At the same time, excess fluid flows via line 137 to valve 139, opens this valve and returns to the storage container via lines 160 'and 112, if necessary via the bearings of the drive device. In a similar way, as already mentioned above, the valves 122, 123 are acted upon by the liquid pressure and held in their closed position when the excess fluid flows back into the reservoir. When the piston 128 in the chamber 126 * reaches the end of its stroke and empties the chamber 126 ', its rod pushes against the switch LS4, opens this switch and interrupts the circuit of the relay R ... opens the relay R., opens the contacts R ₁ and R _{1fi |} so that the solenoid 1 is de-energized so that the valve 130 can return to its inactive or neutral position.

The present control system provides a simple, reliable and immediate actuation for correcting and compensating for the stroke of a drive piston in both directions, so that precise strokes are ensured for all drawing punches 98 of the MaBobine at all times. The Seibet correction of the stroke takes place automatically and smoothly and provides

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ensures that high quality containers are obtained, and furthermore permits the use of a plurality of drawing punches on a single piston rod on each side of the drive piston 94, so that several containers are drawn simultaneously with one stroke of the piston 94 in one direction. The chambers 71, 90 and 92, 126 and 126 ¹ and the bypass line 99 are initially filled with hydraulic fluid via the pump 110 and the lines 120 and 121 before the machine begins to work. During the purging of the bypass line 99, the check valves 101 are opened by being pulled outward on the shaft 204 by hand so that the bypass line 99 is in communication with the chambers 90 and 92. Trapped air is vented from the chambers and the bypass line, as well as from the various pipelines, via suitable air vent valves 260 which are provided with oil diverters to the oil reservoir.

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Claims (7)

Claims 1. A device for deep-drawing seamless containers closed at one end, characterized in that a closed hydraulic circuit is provided, in one branch of which a piston (94) and in the other branch of which a bin and reciprocating yoke (84) is arranged, whereby the piston (94) can be moved back and forth under the mediation of the fluid, which piston rod (96) has a piston rod (96) on both sides and which carries a slide (87), and a regulating tank on each side of the hydraulic circuit on both sides of the piston (94) (126 or 126 ») is provided, which feeds fluid into that part of the hydraulic circuit in which there is a lack of fluid, which is indicated and triggered by a change in the stroke of the piston (94). 2. Apparatus according to claim 1, characterized in that daQ an overload protection device (101) is provided through which the straight effective hydraulic sub-circuit with a bypass line (99) in connection, via the fluid from this sub-circuit drains. 3. Apparatus according to claim 1 or 2, characterized in that each on the piston (94) acting hydraulic Teilkreij with a regulating tank (126) to replenish the fluid. I see is. ' WH / Si -19- .109832 / 0555 4. Apparatus according to claim 1, 2 or 3 »characterized in that that in each regulating container (126) a piston (128) is arranged which actuates the one in the regulating container by means of compressed air Fluid conveyed into the hydraulic circuit. 5. Apparatus according to claim 3 and 4, characterized in that compressed air is applied to the piston when the Ziehstetnpels is enlarged (128) acts, which moves the piston (128) so that Fluidutn from the control container (126) to supplement the fluid in the hydraulic circuit flows. 6. Apparatus according to claim 5 »characterized in that the Supply of compressed air is controlled via a solenoid valve, that actuates a switch on the drawing die. 7. Device according to one of the preceding i.nsprüche, thereby characterized in that the actuation of the drive piston (94) for the drawing punch (98) is connected to a piston (85, 86) Yoke (84) takes place, which is moved back and forth by a crankshaft and the iluidum flow back and forth accordingly leaves. 109832/0555