EP1762340B1 - Clamping device - Google Patents

Abstract

Clamping device comprises an expanding clamping element whereby a flow channel (4) is provided between the first and the second fluid drive fluidically connects the fluid drive (1,2) with each other. The flow channel comprises a valve (5) with an actuator (8), which is actively connected with the both fluid drive for opening and closing of the valve.

Description

The invention relates to a clamping device according to the preamble of patent claim 1.

A clamping device of the type mentioned above for positionally accurate positioning of components is after the DE 297 00 886 U1 known. This consists of an insertable into a component opening Spreizspannelement which is operatively connected to the spreading / despreading within the component opening with a first fluid drive and for tensioning / relaxing the component against a component support with a second fluid drive. The connection of the Spreizspannelements with the first and second fluid drive is realized in this solution by means of a first and second actuating mechanism, ie, the components are mechanically interconnected. Other connectivity options are discussed below.

Such clamping devices are used in particular in the automotive industry. Workpieces to be machined often have to be clamped not only at the processing station, but in particular also positioned accurately positioned. For this purpose, at least one opening is provided on the component (workpiece), in which the clamping device can engage. So that the clamping position is clearly defined, the clamping device is first spread apart within the component opening. Thus, the position of the workpiece with respect to the processing station is clearly defined and independent of manufacturing tolerances with respect to the opening size. In order to secure the workpiece during processing not only in X-Y- (surface of the component support), but also in the Z-direction, this is additionally braced against the component support on the processing station.

In the solution after the DE 297 00 886 U1 This is done via a non-positive connection of the clamping jaws with the workpiece. Alternatively, of course, but also a positive connection for clamping / relaxing against the workpiece support possible. This will be discussed in more detail below.

A disadvantage of the DE 297 00 886 U1 is that for actuating the two fluid drives each separately operated control valves are required, ie to cause the two movements is a relatively complicated control is required.

The sake of completeness is at this point still on the DE 102 38 815 A1 and the EP 0 970 780 A1 pointed.

The former discloses a centering clamp, which is in principle also suitable for clamping a workpiece against a component support. However, in the absence of the above-described spreading function, this device does not work well enough for some applications.

The EP 0 970 780 A1 discloses a spreading element, which, however, is only partially able to clamp a component against a workpiece support, since the clamping function can only be optimally realized if the workpiece has inclined edges.

The invention is based on the object, starting from the DE 297 00 886 U1 to provide a clamping device in which the actuation of the two fluid drives or the clamping elements for spreading / despreading or clamping / relaxing is substantially simplified.

This object is achieved with a clamping device of the type mentioned by the features listed in the characterizing part of patent claim 1.

According to the invention, it is thus provided that between the first and second fluid drive, a fluid duct fluidically interconnecting the fluid drives is provided, which comprises a valve with an actuating element, the opening / closing the valve is operatively connected to one of the two fluid drives.

In other words, according to the invention, the two fluid drives are fluidly connected to each other, wherein a valve controls each, which drive at which time with the control fluid (pressure medium) is applied. In this way, there is an automated sequence of movements of the fluid drives, with only one control signal. This is to apply the tensioning device to the fluid supply to the pressure medium, which then leads without further influence from the outside to the sequence-controlled actuation of the two fluid drives. If the expanded clamping position is to be released again, conversely the other fluid connection of the clamping device is subjected to the pressure medium, so that the fluid drives, which are operatively connected to one another, release the workpiece again in a fixed sequence.

Other advantageous developments emerge from the dependent claims.

The clamping device according to the invention including its advantageous developments according to the dependent claims will be explained in more detail with reference to the drawing of a preferred embodiment.

Figur 1

die erfindungsgemäße Spannvorrichtung in entspreizter und entspannter Position;

Figur 2

die Spannvorrichtung gemäß Figur 1 in gespreizter und gespannter Position; und

Figur 3

eine besondere Ausführungsform des Ventils am erfindungsgemäßen Strömungskanal.

It partially shows in section

FIG. 1

the tensioning device according to the invention in despread and relaxed position;

FIG. 2

the tensioning device according to FIG. 1 in a spread and cocked position; and

FIG. 3

a special embodiment of the valve on the flow channel according to the invention.

The in the Figures 1 and 2 shown clamping device for positionally accurate positioning of components 7 comprises a in one Component opening 8 insertable Spreizspannelement 3, which is operatively connected to the spreading / despreading within the component opening 8 with a first fluid drive 1 and for clamping / relaxing the component 7 against a component support 9 with a second fluid drive 2. The fluid drives 1, 2 are optionally designed to be pneumatically or hydraulically operable, ie the term "fluid" is always understood here in the sense that the pressure medium is either gaseous (eg air) or liquid (eg hydraulic oil).

As in the aforementioned prior art, the fluid drives 1, 2 each comprise a cylinder chamber 10, 11, in which a respective piston 12, 13 is movably mounted. The piston 12, 13 is operatively connected via a piston rod 14, 15 optionally with the Spreizspannelement 3 or the component support 9.

As explained above and as in the embodiment according to the Figures 1 and 2 realized, the Spreizspannelement 3 can be operatively connected via a first adjusting mechanism 20 with the first fluid drive 1 and a second adjusting mechanism 21 with the second fluid drive 2. Alternatively, however, it is just as possible to create another operative connection (eg likewise fluidically) between the fluid drives 1, 2 and the spreading element 3 or the component support 9, ie the solution according to claim 1 takes into account all these possibilities.

With regard to the expansion element 3, it is provided that this has a plurality of radially adjustable expansion jaws 22. These are in the DE 297 00 886 U1 Called "centering body" and create a non-positive bond with the component. As mentioned in the beginning and as in the Figures 1 and 2 shown, the expansion jaws 22 according to the invention are provided with a corresponding projection in order to realize not only a frictional, but a positive connection to the component can. This positive connection is particularly advantageous for a secure clamping of the component against the component support.

Essential for the invention is now that between the first 1 and second fluid drive 2, a fluid drives 1, 2 fluidly interconnecting flow channel 4 is provided which comprises a valve 5 with an actuating element 6, the opening / closing of the valve 5 with a the two fluid drives 1, 2 is operatively connected. In the illustrated embodiment, the flow channel 4 fluidly connects the above-mentioned cylinder chambers 10, 11 of the two fluid drives 1, 2. The flow channel 4, the valve 5 and the adjusting element 6 are an integral part of the clamping device, d. H. arranged within this.

It is further provided that the two fluid drives 1, 2 are arranged in a common housing 16, wherein this is also designed to be displaceable with respect to the component support 9, namely, that the two fluid drives 1, 2 receiving housing 16 in a Guide housing 17 is mounted axially displaceable. The guide housing 17 itself is firmly connected to the component support 9 in the preferred embodiment.

To form the aforementioned second actuating mechanism 21, the piston 13 of the second fluid drive 2 is fixedly connected to the guide housing 17, d. H. a movement of the piston 12 always leads to a relative movement between the housing 16 and the guide housing 17. This will be explained again in detail below.

It is further provided that between a movement of a fluid drive 1 (alternatively, not shown: fluid drive 2) and an opening degree of the valve 5 is a (in the mathematical sense) functional relationship, ie this is invariably adhered to by the components during operation, which but does not mean that he could not be preset arbitrarily, for example, by a corresponding implementation mechanism on the actuator 6th

In the embodiment according to FIGS. 1 and 2 Furthermore, a pressure relief channel 18 with a check valve 19 is provided between the two fluid drives 1, 2 (also within the housing 16).

• Figur 1 zeigt zunächst die Spannvorrichtung in ungespreizter und ungespannter Stellung, d. h. die Spreizbacken 22 sind radial nach innen gezogen und das Gehäuse 16 ist maximal nach oben ausgefahren. Ein Bauteil 7 ist bereits auf der Bauteilauflage 9 platziert.

Finally, the operation of the tensioning device according to the invention will be explained below:

• FIG. 1 shows first the tensioning device in unspreizter and untensioned position, ie the expansion jaws 22 are pulled radially inward and the housing 16 is extended upwardly at maximum. A component 7 is already placed on the component support 9.

Pressure medium (eg air, oil) is now supplied via port 23. This has the consequence that the piston 12 moves upwards within the cylinder space 10. About the operative connection to the expansion element, which is mechanically formed in this case and according to the DE 297 00 886 U1 may correspond, the spreader jaws 22 are pressed radially outwards, until they come to rest at the edge of the component opening.

Depending on the predefined operative relationship, the fluid drive 1 or the piston 12 controls the valve 5 via the adjusting element 6, which in turn determines the flow passage through the flow channel 4 mentioned above. The movement of the piston 12 thus results in that the pressure medium can also reach the second fluid drive 2. The pressure medium supply to the second cylinder chamber 11 in turn has the consequence that the housing 16 is pulled or pressed down within the guide housing 17. In addition to the spreading action on the expanding jaws 22, the pressure medium supply thus also leads to a tensioning of the workpiece on the component support 9 via the housing 16 and the expansion jaws 22 formed in a form-fitting manner with the component.

The Spreizspannstellung is then in FIG. 2 achieved and presented. To loosen it is now via the port 24 pressure medium It should be noted that the two in FIG. 2 Ports shown 24 are connected directly to each other via a common pressure medium connection. The pressure medium entering at the fluid drive 1 causes the spread position to be released, wherein at the same time the flow conditions in the flow channel 4 are defined via the control element 6 and the valve 5.

The medium entering the fluid drive 2 at the connection 24 causes the housing 16 to be lifted upwards within the guide housing 17. The pressure medium below the piston 13 leaves, as long as the valve 5 is still open, the tensioning device via the flow channel 4 and the port 23. Once the valve 5 is closed due to the operative connection to the piston 12, the pressure medium, if this should be necessary but also leave the cylinder chamber 11 via the provided with a check valve 19 pressure relief channel 18 (and finally again via the terminal 23) to the piston each corresponding recesses are schematically indicated to make understand that the pressure medium can flow to the corresponding terminals ,

After this loading of the tensioning device with the pressure medium via the port 24, this is thus again in a despread and relaxed position, and all this, without the need for an externally actuated, control engineering influence. The connection according to the invention of the two fluid drives thus creates the possibility of being able to combine two movements without external control technology in a simple manner.

With reference to FIG. 3 Finally, an embodiment is provided in which the valve 5 is designed as a spring-loaded valve and the piston 12 is designed as a pull rod actuator 6 is provided, the valve 5 against the force of the piston during a movement of the piston 12 (in the picture above) Spring 25 opens and in this way a fluid flow from the first cylinder chamber 10 via the flow channel 4 to the second Cylinder space 11 allows. In this embodiment, the piston moves as shown FIG. 3 apparent, ie, almost to its first (in the picture upper) end position before then actually opened the valve 5 and thus the clamping movement is initiated (the time of opening the valve can thus be defined over the length of the tie rod).

LIST OF REFERENCE NUMBERS

1

first fluid drive

2

second fluid drive

3

Spreizspannelement

4

flow channel

5

Valve

6

actuator

7

component

8th

component opening

9

component support

10

first cylinder space

11

second cylinder space

12

Piston of the first fluid drive

13

Piston of the second fluid drive

14

piston rod

15

piston rod

16

casing

17

guide housing

18

Pressure relief duct

19

check valve

20

first actuating mechanism

21

second actuating mechanism

22

Moveable

23

connection

24

connection

25

feather

Claims (10)

1. A clamping device for the precise positioning of components (7), comprising
   an expanding clamping element (3) that can be inserted in a component opening (8), which element is effectively connected to a first fluid drive (1) for expanding/contracting inside the component opening (8) and to a second fluid drive (2) for clamping/release of the component (7) against a component support (9),
   characterised in that
   a flow channel (4) fluidically connecting the fluid drives (1, 2) to each other is provided between the first (1) and second fluid drive (2), which channel comprises a valve (5) with an adjusting element (6) which is effectively connected to one of the two fluid drives(1, 2) for opening/closing the valve (5).
2. The clamping device according to Claim 1,
   characterised in that
   the fluid drives (1, 2) each comprise a cylindrical space (10, 11) in which a piston (12, 13) is moveably mounted.
3. The clamping device according to Claim 2,
   characterised in that
   the flow channel (4) connects the cylindrical spaces (10, 11) of the two fluid drives (1, 2) to each other fluidically.
4. The clamping device according to Claim 2 and 3,
   characterised in that
   the piston (12, 13) is effectively connected by means of a piston rod (14, 15) either to the expanding clamping element (3) or to the component support (9).
5. The clamping device according to one of Claims 2 to 4,
   characterised in that
   the two fluid drives (1, 2) are arranged in a common housing (16).
6. The clamping device according to Claim 5,
   characterised in that
   the housing (16) is designed so that it is displaceable with respect to the component support (9).
7. The clamping device according to Claim 5 or 6,
   characterised in that
   the housing (16) receiving the two fluid drives (1, 2) is mounted in a guide housing (17) so that it is axially displaceable.
8. The clamping device according to Claim 7,
   characterised in that
   the guide housing (17) is fixedly connected to the component support (9) and in that the piston (13) of the second fluid drive (2) is connected in a fixed position to the guide housing (17).
9. The clamping device according to one of Claims 1 to 8,
   characterised in that
   a pressure relief channel (18) with a check valve (19) is provided between the two fluid drives (1, 2).
10. The clamping device according to one of Claims 1 to 9,
    characterised in that
    the expanding clamping element (3) is effectively connected by means of first adjusting mechanics (2) to the first fluid drive (1) and by means of second adjusting mechanics (21) to the second fluid drive (2).

Images