EP2016290B1 - Procedure for the loading of a working cylinder, control module for it, working cylinder and utilization of the same - Google Patents

Abstract

The invention demonstrates how energy saving working cylinders are loaded with fluid under pressure in order, for example, to power devices for tensioning (toggle joint tensioning apparatus), and/or compressing, and/or jointing, and/or stamping, and/or embossing, and/or punching, and/or welding, if necessary under the interposition of gearing parts such as guides, parallelogram gears, toggle joint articulations, or the like, with the fluid supply being controlled in such a way during the no-load stroke (idle stroke) of the piston (4) that only the forces of inertia and/or weight and/or the forces of friction of moveable parts are overcome and are not acted upon by the fluid pressure until the power stroke of the piston (4).

Description

The invention relates to a toggle clamping device with a cylinder, a piston, a sealing element, a piston rod, a toggle joint assembly, a clamping head and a clamping arm, wherein in the cylinder, the piston is sealed by the sealing element liftable movable by compressed air, wherein the piston via the piston rod and the toggle link assembly, which is located in the chuck, moves the clamp arm, and the cylinder has a cylinder bottom and a cylinder cover, with a further channel disposed therein, through which engages the piston rod in the chuck.

Toggle jigs of the presumed kind are used in large numbers in the bodywork of the automotive industry. There, they usually serve to hold together sheet-metal components that are joined together by clinching (local high compression), gluing or spot welding. In toggle clamping devices of this type usually drives a piston via a piston rod with the interposition of a toggle joint arrangement to a pivoting clamping arm, which with an abutment, im Technical jargon also called "pine", cooperates. Between clamping arm and abutment (jaw) to be held sheet metal parts are stretched, in order to connect them permanently. Devices of this kind are, for example, in the applicant's catalogs "production program", "clamping technology for professional series production", "clamping systems, handling, forming technology, punching, flanging, pressure joining, embossing" and in the patents DE 196 16 441 C1 . DE 198 24 579 C1 and DE 199 30 990 C1 to find.

In all these toggle clamps, the full pressure force is only needed immediately during the last part of the working stroke, just when clamping by the tensioning arm. This implies that for 90 percent or more of the so-called idle stroke, also called Anstellhub, the piston in question with its piston rod only a small force to overcome the friction and certain inertia and weight forces, is necessary. The supply of pressurized fluid, usually compressed air and thus the pump power and its drive power is required in the prior art for the entire stroke of the associated piston with piston rod, toggle joint and arm, which means that constantly the majority of Drive energy for the provision of the fluid, especially compressed air, is lost.

From the DE 195 12 429 A1 is a single or multi-stage differential cylinder previously known, with surface-dependent training and entry sequence of multi-stage version with a bottom sides acting Ausfahrdruckmittelleitung and acting on the annular spaces, by a spring-loaded, aufsteubares by Einfahrdruckmitteldruck check valve Einfahrdruckmittelleitung, via an upstream spool with the positions "Extend-stop-retract" are controllable. This device is characterized by a connecting line between the cylinder chambers, in which a spring-loaded, on the one hand under the action of the Einfahrdruckmitteldrucks and on the other under the action of the Ausfahrdruckmitteldrucks plus a load component closing the check valve, at the closing of the retraction-side check valve opens. Such a single and multi-stage differential cylinder is to be used as an actuator for pincer-like crushing tools, in which it is desirable that the Anstell- and the release stroke are traversed faster than the subsequent to the Anstellhub working stroke. Therefore, the cylinder chambers, so the bottom pressure chamber and the so-called annulus, when extending the cylinder initially connected to each other with the effect that the displaced during extension from the annulus pressure fluid flows into the cylinder pressure chamber, which flows through the pressure medium fed into the cylinder pressure chamber by the pump Accelerated deployment process accelerating supportive. This switching situation is maintained until the extending piston rod encounters the initiation of the actual working stroke defining resistance. This Resistance or the so-called load component leads to a pressure increase in the cylinder pressure chamber, which causes the closing of the inserted into the connecting line between the cylinder chambers check valve, so that the further extension of the cylinder takes place only under the action of the pressure medium fed through the pump in the cylinder pressure chamber, then also correspondingly slower in the now on the cylinder and possibly then on the object acting forces account bearing way.

The DE 19 41 785 A1 relates to a pneumatically or hydraulically driven power stroke cylinder, in particular for cutting, embossing or pressing tools, wherein the drive power is supplied to the cylinder via a working pressure line and a back pressure line so that the working stroke of the piston is divided into a forward stroke, caused by the back pressure only a correspondingly low differential pressure acts on the piston and a power stroke, in which the back pressure is turned off by valve action, and the full power of the piston drives.

The differential pressure acting on the piston arises because the same drive energy presses on both sides in opposite directions on different sized piston surfaces.

The DE 333 903 C describes a hydraulic pressing plant, wherein the plunger is connected to an auxiliary piston and the pressing cylinder with an auxiliary cylinder of smaller volume. The auxiliary cylinder is connected to the pressurized water, the pressure cylinder to water under ordinary pressure and both cylinders are connected by a controlled valve with each other in such a way that pressurized water passes only when placing the plunger on the workpiece in the press cylinder. The plunger and the auxiliary piston have a top of the auxiliary piston closed by a valve, connected at the bottom of the auxiliary piston by a transverse bore with the press cylinder longitudinal bore in which a control rod is guided, which acts with its upper end on the valve and so far with its lower end protrudes from the plunger that it opens the valve at or immediately before placing the latter on the workpiece and pressure water can pass through the longitudinal bore and transverse bore in the press cylinder.

The DE 10 2004 027 849 A1 relates to a drive unit, in particular for an injection unit or an ejector of an injection molding machine, with a working cylinder having three pressure chambers, one of which has an acting in the extension direction small effective area, one acting in the extension direction large effective area and an acting in the retraction effective area, and with a valve arrangement for acting on the pressure chambers in each case with high pressure or low pressure. The device is characterized by a high-pressure accumulator and a low-pressure accumulator, which are connectable via the valve arrangement with the pressure chambers, wherein the force acting in the retraction effective area and one of the effective acting in the extension direction effective surfaces are subjected to high pressure both during rapid deployment and during rapid retraction.

The invention has the object of providing a toggle lever device according to the assumed genus in such a way that it works more energy efficient and manages with simple, robust control means for the control of the compressed air to the cylinder chambers.

The object is solved by the reproduced in claim 1 features.

To adjust the different pressure forces during the idle stroke (Anstellhub) and the power stroke, so when clamping by the tension arm analogous to the performance, in particular liter power of air, is in the toggle lever according to the invention during the idle stroke on both sides of the working piston, via the piston rod and the toggle joint arrangement the Clamping arm drives, effective only with the differential force in the direction of the working stroke, resulting from the difference between the acted upon by the compressed air piston surface in the working cylinder and the opposite side of the piston ring surface, ie in Zylinderrückhubraum. Compressed air consumption and in particular energy consumption for the pump and its drive motor and thus energy consumption for the generation of compressed air, thereby significantly, for example, reduced by 50%.

For the initiation of the actual working stroke, so when clamping by the clamping arm, the piston ring surface, so the Zylinderrückhubraum relieved of pressure, while the piston surface is acted upon in the working cylinder space by the full pressure medium pressure. The full force of the compressed air is then available immediately from the beginning of the tensioning process by the clamping arm of the toggle lever tensioning device. The retraction of the piston rod and thus the open pivoting of the clamping arm is done by the pressurization of the piston ring side, so the Zylinderrückhubraumes by the previously reversed spool.

Toggle clamps can be used with great advantage in the bodywork of the automotive industry. Existing production lines can be provided without structural changes with such toggle lever tensioning devices as are the subject of the invention, thereby reducing energy costs to considerably reduce the operation of such production lines. It is particularly advantageous that the control of the pressure medium pressure with completion of the idle stroke (Anstellhubes) by a robust piston valve, which is operated by the piston rod driving piston directly. Complicated valve controls are not required. The control of the spool takes place directly through the piston of the drive unit for the clamping arm. This reduces the number of parts and avoids complicated wearing parts. During the idle stroke, there is no connection between the piston rod or piston and the piston valve. Rather, the piston valve is space-saving in the cylinder cover, which separates the cylinder, in which the piston is longitudinally displaceable and sealing, separates from the clamping head, arranged longitudinally displaceable and sealing.

Inventive embodiments are described in claims 2 to 4 .

Fig. 1

eine Kniehebelspannvorrichtung im Längsschnitt, in teilweise geöffneter Stellung, und

Fig. 2

die aus Fig. 1 ersichtliche Kniehebelspannvorrichtung, gleichfalls im Längsschnitt, in Spannstellung.

Further features and advantages will become apparent from the following descriptions of the drawings, in which the invention - partly schematically - is illustrated in several embodiments. Show it:

Fig. 1

a toggle lever device in longitudinal section, in partially open position, and

Fig. 2

from Fig. 1 apparent toggle clamping device, also in longitudinal section, in clamping position.

In the drawing, reference numeral 1 designates a cylinder having a cylinder bottom 2 and a cylinder cover 3. Cylinder bottom 2 and / or cylinder cover 3 can be connected by screws (not shown) with the actual cylinder 1 releasably and replaceably.

The cylinder 1 may be circular in an orthogonal to its longitudinal axis guided cross-section, but also oval, rectangular, flat oval or otherwise designed.

In the cylinder 1, a piston 4 in the longitudinal axis direction in opposite directions, that is arranged in the direction of X or Y sealed by a sealing element 5 liftable. On one side of the piston 4, a piston rod 6 is assigned, via which a clamping arm 7 is moved via a toggle joint arrangement 8. The clamping arm 7 interacts with an abutment, not shown, also called jaw, together. The basic structure of toggle clamps is state of the art and will not be described here for the sake of simplicity. Devices of this type can be found in the attached Bibliography apparent publications are taken, as they are also described in the introduction to the specification of this patent.

In a cylinder wall 9 is a longitudinal channel 10 which is connected to the cylinder cover 3 end facing compressed air conducting with a transverse channel 11, which opens at one end into the working cylinder chamber 12 and here to a not drawn control system for a suitable fluid supply and - discharge or vent connected. This fluid is compressed air, which is available everywhere in the factories and especially in production lines.

At a distance from its other end of the longitudinal channel 10 is connected in compressed air conduction with a arranged in the cylinder cover 3 branch channel 13, while the longitudinal channel 10 is also connected at its end in compressed air-conducting connection with a channel section 14 compressed air conducting, which opens into a chamber 15 fluid-conducting.

In the cylinder cover 3, a further channel 16 is arranged, which opens into a cylindrical bore 17. This channel 16 is followed by a chamber channel 18, which opens at one end compressed air conducting to the channel 16 and at the other end into the chamber 15.

In the bore 17, a piston slide 19 is guided longitudinally displaceable and sealing, which protrudes with a certain length in a Zylinderrückhubraum 21 and is guided in the chamber 15 with a piston 20 longitudinally displaceable and sealing. The chamber 15 is thereby subdivided into two cylinder chambers, wherein in the one cylinder chamber 22 of the chamber channel 18 discharges compressed air, while in the cylinder chamber 23 of the channel portion 14 discharges air pressure.

The piston slide 19 has a longitudinal channel 24, which extends in the illustrated embodiment coaxially to the longitudinal axis of the spool 19 over part of its length and has an orthogonal to the longitudinal axis extending compressed air, connected to the longitudinal channel 24 branch channel 25.

• Bei der aus Fig. 1 ersichtlichen Stellung ist der Querkanal 11 an eine nicht dargestellte Druckluftquelle angeschlossen. Dadurch wird der Arbeitszylinderraum 12 mit Druckmitteldruck über den Längskanal 10, den Abzweigkanal 13 sowie den Zweigkanal 25 und den Längskanal 24 im Kolbenschieber 19 an den Zylinderrückhubraum 21 mit demselben Druckmitteldruck beaufschlagt. Das bedeutet, dass sowohl der Arbeitszylinderraum 12 als auch der Zylinderrückhubraum 21 durch Druckluft gleichzeitig beaufschlagt sind. Dadurch wirkt die Druckluft von beiden Seiten auf den Kolben 4 ein. Da aber die Druckluft auf der einen Seite, auf der sich die Kolbenstange 6 befindet, eine geringere Fläche, eben nur die Ringfläche, beaufschlagt, ergibt sich eine in Richtung Y, also in Arbeitsrichtung wirkende Hubverstellungskraft, die durch die Differenz der fluidwirksamen Kolbenflächen bestimmt wird. Infolgedessen wird der Kolben 4 sowie die Kolbenstange 6 und der Spannarm 7 über die Kniehebelgelenkanordnung 8 beim Leerhub nur mit einer relativ geringen Antriebskraft bewegt. Infolgedessen verringert sich die beim Leerhub (Anstellhub) erforderliche Antriebsenergie entsprechend der druckmittelwirksamen Flächen im Arbeitszylinder, zum Beispiel um 50 Prozent. Man kann dies auch durch die Wahl der druckluftwirksamen Kolbenflächen bestimmen, zum Beispiel dadurch, dass man die Querschnittsfläche der Kolbenstange 6 entsprechend variiert. Man hat es zum Beispiel bei Kniehebelspannvorrichtungen in der Hand, die Kolbenstange 6 im Durchmesser zu verringern, um dadurch während des Leerhubes (Anstellhubes) die aufzuwendende Energie noch weiter herabzusetzen. Trifft der Kolben 4 auf die Stirnseite des Kolbenschiebers 19, so wird dieser entsprechend in seiner Längsachsrichtung verschoben bis er die aus Fig. 2 ersichtliche Stellung erreicht hat. In dieser Stellung ist der Abzweigkanal 13 von dem Zylinderrückhubraum 21 abgesperrt und über den Längskanal 24 im Kolbenschieber 19 und seinen Zweigkanal 25 an den Kanal 16 druckluftleitend angeschlossen, wodurch der Zylinderrückhubraum 21 entlüftet wird. Diese Entlüftung kann über ein geeignetes nicht dargestelltes Steuerungssystem geschehen.

The mode of action of the Fig. 1 and 2 apparent toggle tensioning device is the following:

• At the Fig. 1 apparent position of the transverse channel 11 is connected to a compressed air source, not shown. As a result, the working cylinder space 12 is pressurized with pressure medium pressure via the longitudinal channel 10, the branch channel 13 and the branch channel 25 and the longitudinal channel 24 in the spool valve 19 to the Zylinderrückhubraum 21 with the same pressure medium pressure. That means, that both the working cylinder space 12 and the Zylinderrückhubraum 21 are acted upon by compressed air simultaneously. As a result, the compressed air acts on the piston 4 from both sides. However, since the compressed air on one side, on which the piston rod 6 is, a smaller area, just the annular surface, acted upon, there is an acting in the direction Y, ie working direction Hubverstellungskraft, which is determined by the difference of the fluid-effective piston surfaces , As a result, the piston 4 and the piston rod 6 and the clamping arm 7 is moved via the toggle lever assembly 8 during the idle stroke only with a relatively small driving force. As a result, the drive energy required during the idle stroke (adjustment stroke) decreases corresponding to the pressure-medium-effective areas in the working cylinder, for example by 50 percent. This can also be determined by the choice of the compressed air-effective piston surfaces, for example by varying the cross-sectional area of the piston rod 6 accordingly. It is for example in toggle clamps in the hand to reduce the piston rod 6 in diameter, thereby further reduce the energy to be expended during the idle stroke (Anstellhubes). Meets the piston 4 on the front side of the spool 19, it is accordingly moved in its Längsachsrichtung until he made the Fig. 2 has reached an apparent position. In this position, the branch channel 13 is shut off from the Zylinderrückhubraum 21 and connected via the longitudinal channel 24 in the spool valve 19 and its branch channel 25 to the duct 16 compressed air-conducting, whereby the Zylinderrückhubraum 21 is vented. This venting can be done via a suitable not shown control system.

The retraction of the piston rod 6, so a movement in the direction X (opening stroke) is done by appropriate control of the control device, not shown, whereby the Druckmitteldruckbeaufschlagung the piston ring side, so the Zylinderrückhubraums 21 by the previously reversed, in this case designed as a spool valve 19 valve. In this case, the channel 16 is connected via the controller to the pressure medium pressure. The compressed air is thereby introduced via the channel 16 and the longitudinal channel 24 in the spool valve 19 in the Zylinderrückhubraum 21. Via the chamber channel 18, the pressure medium pressure also propagates into the chamber part 22 and acts on the piston 20 and thereby keeps the spool 19 in its off Fig. 2 shown position.

When introducing the idle stroke (Anstellhubes) in the Y direction, the compressed air in turn propagates through the transverse channel 11 and the channel 10 to the branch channel 13 and also via the channel section 14 into the chamber 15 and acts on the piston 20, whereby this in his Fig. 1 is displaced apparent position, whereupon the cycle described above can be repeated.

For the initiation of the power stroke thus a reversal takes place, such that the Zylinderrückhubraum 21 is then no longer acted upon with compressed air, but only the working cylinder space 12, whereby the full pressure medium pressure is at the initiation of the power stroke available.

The reference numeral 40 denotes a device only schematically indicated for detecting the position of the piston rod 6. This device 40 may be a so-called cassette known from toggle clamping devices, in which the respective position of the piston rod 6, for example via a switching lug 41, can be detected by means of pneumatic switches, microswitches, inductive switches or the like. The device 40 may also be arranged in the form of a cassette directly associated with the cylinder 1, for example in a recess thereof, as shown in FIG Fig. 2 is shown, where the device for detecting the various positions of the piston rod 6 and thus indirectly also the angular position of the clamping arm 7 is disposed in a located on the back of the clamping head 42 slot 43. This slot 43 may preferably extend in the longitudinal axis direction of the clamping head 42 and thus parallel to the stroke direction of the piston rod 6 or transversely thereto. Preferably, the device 40 seals the slot to the outside largely, for example, liquid and dustproof from. The device 40 can also be designed as a so-called adaptive cassette, in which by single or multiple driving certain positions these positions in a memory electronically can be stored and dismantled to assign, for example, a clamping arm 7 different angular positions. The device parts 44, 45 may be switches, for example electrical switches or inductive switches, which are damped by the switching lug 41. The data is retrieved via a suitable electrical or electronic plug 46 and transmitted via a line, for example to a remote control station, a data processing system or the like. These data may be included in a production control or regulation and may be located in, for example, a production line in the body shop of the automotive industry.

Reference numeral 47 designates a seal through which the piston rod 6 can be led out of the working cylinder space 1 in a compressed air-tight manner.

reference numeral

1

cylinder

2

cylinder base

3

cylinder cover

4

piston

5

sealing element

6

piston rod

7

clamping arm

8th

Toggle lever arrangement

9

cylinder wall

10

longitudinal channel

11

Querkanal

12

Working cylinder chamber

13

branch channel

14

channel section

15

chamber

16

channel

17

drilling

18

chamber channel

19

spool

20

piston

21

Cylinder return

22

cylinder space

23

"

24

longitudinal channel

25

Zweigkanal

40

Device for detecting

41

Schaltfahne

42

clamping head

43

slot

44

contraption

45

"

46

plug

47

poetry

X

stroke direction

Y

"

bibliography

• Prospectus of Tünkers Maschinenbau GmbH, Ratingen, "Clamping technology for professional series production"
• Prospectus of Tünkers Maschinenbau GmbH, Ratingen, "Production Program"
• Prospectus of Tünkers Maschinenbau GmbH, Ratingen, "Clamping Systems, Handling, Forming Technology"
• DE 195 12 429 A1
• DE 19 41 785 A1
• DE 333 903 C
• DE 10 2004 027 849 A1
• DE 196 16 441 C1
• DE 198 24 579 C1
• DE 199 30 990 C1

Claims (4)

1. Toggle lever clamping device having a cylinder (1), a piston (4), a sealing element (5), a piston rod (6), a toggle lever joint arrangement (8), a clamping head (42) and a clamping arm (7), where the piston (4), which is sealed by the sealing element (5) and can be moved up or down (X or Y) in the cylinder (1), can be moved by compressed air, where the piston (4) moves the clamping arm (7) by means of the piston rod (6) and the toggle lever joint arrangement (8), which is located in the clamping head (42), and the cylinder (1) incorporates a cylinder bottom (2) and a cylinder cover (3) in which is disposed a further duct (16) and through which the piston rod (6) extends into the clamping head (42), characterised in that the piston (4) during the idle stroke (Y) is both at the piston end directed towards the work cylinder chamber (12) and at the annular piston end directed towards the cylinder return chamber (21) subjected to the same air pressure from a piston valve (19) which is longitudinally displaceably and sealingly guided in a bore (17) in the cylinder cover (3) and which incorporates coaxially with the longitudinal axis a longitudinal duct (24) and connected to it a branch duct (25) and that to initiate the power stroke the piston (4) actuates the piston valve (19) and displaces it in a longitudinal direction, and where the piston valve (19) vents the cylinder (1) on the annular piston side via the longitudinal duct (24) and the branch duct (25) and the further duct (16).
2. Toggle lever clamping device in accordance with claim 1, characterised in that a transverse duct (11) which is connected at one end to a compressed air source or can be vented and which can be connected to the work cylinder chamber (12) and which can via a further longitudinal duct (10) disposed in one wall (9) of the cylinder (1) and a branch duct (13) in a first position of the piston valve (19) be connected to the cylinder return chamber (21) via the longitudinal duct (24) in the piston valve (19), where the longitudinal duct (24) in the piston valve (19) can be connected via the branch duct (25) alternatingly in a first position of the piston valve (19) to the further longitudinal duct (10) or in a second position of the piston valve (19) be connected to the further duct (16) which can either be connected to the compressed air source or can be vented via the cylinder return chamber.
3. Toggle lever clamping device in accordance with claim 2, characterised in that the piston valve (19) is longitudinally displaceably and sealingly guided in a bore (17) via a piston (20), where the piston (20) is disposed in a chamber (15) which can either be connected to the compressed air source via a chamber duct (18) or can be vented, while the cylinder chamber of the chamber (15) disposed on the opposite side is connected to the further longitudinal duct (10) via a duct portion (14).
4. Toggle lever clamping device in accordance with claim 3, characterised in that the bore (17), the piston valve (19) and the cylinder chambers (22, 23) which are separated from one another by the piston (20) of the piston valve (19) are disposed in the cylinder cover (3) and that the longitudinal axis of the piston valve (19) extends parallel to the longitudinal axis of the piston rod (6) and that the piston valve (19) can be pushed into the cylinder return chamber (21) with a limited longitudinal portion and is arranged so that it can be displaced by the piston (4) when the power stroke is initiated.

Images