DE19912378A1 - Suction hoist has operating units, suction plate, suction surface, operating chambers, pipes and vacuum generating unit - Google Patents

Abstract

The suction hoist has at least one operating unit (1) for raising and lowering at least one suction plate (3) which defines a suction chamber (7) evacuable when placed on a suction surface (5). The operating unit has an operating chamber (11) which can be evacuated by means of a vacuum-generating unit (31). The suction plate is fixed to one end of an axially movable bar (4). The operating unit has at least one first operating chamber (10) which can be evacuated by means of a first pipe (35). A second pipe (36) leads from the first chamber to the suction chamber. A second chamber is connected by at least one third pipe (37) to the suction chamber.

Description

State of the art

The invention is based on a lifting suction device for lifting of workpieces with suction surfaces according to the generic term of claim 1.

Such lifting suction devices or lifting suction devices are used in particular in workpiece transport devices. They can be used to manufacture workpieces, for example be sucked in and lifted up to be transported afterwards become. This is common in sheet metal processing, for example, where one cut out of a larger sheet Piece of sheet metal for further processing from the base sheet must be highlighted. After that, either Base plate can be transported away or it can separated piece by means of the horizontally movable Hubsaugers are transported away. After correct Positioning of the separated workpiece becomes this detached from the vacuum cleaner and can be further processed. A  reliable working suction device of this type is from the international application WO 89/00965 known.

There can be rows or two-dimensional fields of such Lift suction cups can be provided to cut from a sheet of metal finished workpieces in several places at the same time to attack and take up. It is known through suitable control of the suction cups, e.g. B. when lifting smaller ones Parts only to activate those suction cups that are above the are arranged to be lifted. To increase the Operational safety, it is also desirable to take precautions to provide for the interference or injury from not be able to avoid sufficiently firmly sucked in workpieces. Suitable controls with the associated sensors can Complicate systems with lifting suction devices and make it more expensive.

The invention and its advantages

The lifting suction device according to the invention with the features of claim 1 is characterized in that increased operational safety without any design effort for suitable sensors and controls can be achieved. Because if the working unit has at least one for lifting a workpiece evacuable working chamber, which preferably can only be evacuated through the suction chamber, then a lifting of the workpiece is reliably prevented, as long as the suction chamber is not as gas-tight as possible it is concluded that an evacuation also as a lifting chamber identifiable working chamber through the suction chamber through is possible. Once the seal between the suction plate and workpiece suction surface due to, for example Surface defects of the workpiece is insufficient because of the secondary air flowing in in the area of the suction plate the lifting chamber cannot be evacuated as much as it is for a  Lifting of the workpiece is required. This is automatic without any suction sensors or the like and without appropriate control ensures that only one safe and effective suction attack of the suction plate on Workpiece can be lifted.

According to an advantageous embodiment of the invention works the work unit fully pneumatic, so that no electrical or mechanical drives for the lowering or Lifting movements are required. This is achieved in that the work unit at least one by means of a Vacuum generating device via at least a first Line evacuable, axially variable first Has working chamber in which the end facing away from the suction plate a rod, at the other end of which the suction plate is attached. From the first chamber leads at least a second line to the suction chamber. Furthermore, an as Lifting chamber acting axially variable second Chamber of Labor provided that has at least a third Line is connected to the suction chamber. This Construction creates the opportunity to lower the Suction plate required movement by evacuation to bring about the first working chamber. The suction chamber will via the second line through the first working chamber evacuated through, this evacuation only then can be made sufficiently strong if a reliable sealing seat of the suction plate on the suction surface is guaranteed. As soon as the evacuation of the suction chamber has generated sufficient negative pressure in this, then the second working chamber acting as a lifting chamber via the third Line evacuated, this evacuation only until Lifting the workpiece can progress if throughout the suction plate largely gas-tight on the Suction surface adheres. Due to the appropriate gas-carrying Connection of the different chambers in which the first Working chamber, the suction chamber and the second  Working chamber are connected in series, is thus an imperative order of their evacuation and thus the associated work strokes or activities of the work unit fixed. The first step is to evacuate the lowering the suction plate in the first working chamber time-delayed subsequent second step an evacuation of the Suction chamber for safe attack of the lifting device on Workpiece and then time-delayed evacuation of the second working chamber, which is then used to lift the Workpiece leads. For following this order are no control valves or the like. required.

According to a further advantageous embodiment of the invention is the first line to a vacuum generating device connected, the one fed by a compressed air source Has injector nozzle, preferably between Compressed air source and injector nozzle a control valve, in particular in the form of a 3/2-way valve with ventilation option is arranged. Through this control valve, the entire Work movement described initiated or canceled so that there is no additional valve to control the lowering and lifting movements of a single work unit is required. These movements can only be done by Connection of the first line with the working one Vacuum generating device can be carried out. Further Control valves can be provided and especially for the self-regulating operation of several parallel work units be beneficial.

To keep the order of Evacuation processes is one of the Invention provided that the second line as a throttle line is formed, which has a flow resistance that is greater is as the flow resistance of the first line, where preferably the flow resistance of the first line between approx. 20% and approx. 80%, in particular between approx. 40%  and about 60% of the flow resistance of the second line is. This is an evacuation of the first working chamber possible, although this remains open towards the suction chamber and therefore, secondary air through the second line into the first Working chamber is sucked in as long as the suction plate is not on Workpiece lies tight. The second line can expediently through the rod carrying the suction plate be passed so that a special line, for. Legs Hose line, can be omitted. The third line can expediently be designed as a bore through the suction plate, the flow resistance of the third line in turn on the flow resistance of the upstream lines so can be agreed that an effective evacuation of the second working chamber only if it is sufficiently safe Suction attack on the workpiece is possible. At a Embodiment with a single work unit needs Except for the third line, no further line in the second Chamber of Labor to be led, making a special one simple construction is possible.

A particularly compact design of the lifting suction device is according to a special embodiment of the invention possible that the first working chamber within the second Working chamber, preferably coaxially with this, is arranged. The first line can expediently be located within the second Working chamber to be led to the first working chamber. For Allow a relative movement of the working chambers the first line flexible and at least in sections for example in the form of a pressure-resistant plastic hose be trained.

According to a further advantageous embodiment of the invention is the first working chamber and / or the second Working chamber by an axially variable Bellows enclosed. Compared to one that is also possible Formation of the chamber walls by telescopic  interlocking container sections is a solution with Bellows, especially round bellows especially cost-effective and gastight without great design effort sealable. A bellows can, for example, by suitable Diameter retaining rings or spacer rings against radial Constriction be secured so that an evacuation in the essentially only leads to an axial shortening.

According to a further advantageous embodiment of the invention is in the first line between vacuum generation institution and first working chamber at least one Control valve arranged so that it is controlled so that it sufficient vacuum in the suction chamber and / or in the second working chamber held in an open position and at ambient pressure in the suction chamber and / or in the second working chamber can be switched into a locked position. This can ensure that when a Workpiece rests on the suction plate and the pressure in the Suction chamber and the second working chamber that sinks Suction through the valve in the open position is maintained while in the absence of a Workpiece and corresponding ambient pressure in these Chambers a separation of the work unit from Vacuum generator can be done. In group operation of several work units, the suction power of one closed vacuum generating device on those Work units are concentrated in their area Workpiece is located without leakage air by unusable Work units is sucked in. The control valve is preferably designed as a pulse valve that in the absence a new control pulse remains in the position in which it was set by the previous control impulse. It is preferably pneumatically controllable and / or pneumatic operable, at least one line from the second Working chamber or the suction chamber to the control valve can lead to the in the lifting chamber or the suction chamber  existing pressure for control, switching or actuation of the valve.

In particular, at least a fourth line can be provided be from the second chamber to a first Vacuum chamber of the control valve leads. The control valve can in addition to this first vacuum chamber, a second Have vacuum chamber with a first control line one in the direction of the second vacuum chamber Check valve connected to the first vacuum chamber is. Preferably, the control valve can be designed such that it is biased into an open position and only then into one Lock position switches if only in the second Vacuum chamber is under vacuum or when the pressure in this chamber is lower than the pressure in the first Vacuum chamber.

Such work units are particularly suitable for the Group or parallel operation of a variety of Work units, for example, in a regular Area distribution on a common, possibly horizontal movable frame can be arranged and the preferably constructed identically and / or to the same Vacuum generating device can be connected. In In such a case, it is particularly advantageous to use the aforementioned Control lines of the work units via at least one Connecting line to connect. The following Description of preferred embodiments is explained that such a connection enables the establishment of intelligent, allows self-directed groups of work units at those automatically work units that are during of a lifting process not above a workpiece suction surface, automatically from the vacuum generating device are separated, whereby the Suction energy of the vacuum generating device on the  work units each attacking the workpiece can be concentrated.

Further advantages and advantageous configurations of the Invention are the following description, the Drawings and the claims, the wording is made by reference to the content of the description.

drawing

Embodiments of the subject of the invention are in shown in the drawings and below described. Show it:

Fig. 1 is a schematic axial section through an embodiment of a device according to the invention Hubsaug,

Fig. 2 is a functional schematic of another embodiment of a Hubsaugeinrichtung (a) according to the invention at rest, (b) with a lowered onto the workpiece suction cup and (c) with raised workpiece, and

Fig. 3 is a schematic pneumatic diagram of another embodiment of a lifting suction device according to the invention with several connected to a common vacuum generator, connected to each other for mutual control.

Description of the embodiments

The lifting and suction device 1 shown schematically in FIG. 1 has an exclusively pneumatically operable working unit 2 for lifting and lowering a suction plate 3 , which is attached to the lower end of an axially or vertically movable rod 4 designed in the manner of a piston rod. The suction plate or suction cup 3 , which is open at the bottom, is intended to be used on an essentially smooth, in particular flat, suction surface 5 of a workpiece 6 , e.g. B. a piece of sheet metal to be placed and limited together with the suction surface when the suction plate abuts the workpiece, a suction chamber 7 , which is open at the bottom in the illustrated idle state of the work unit.

The working unit 2 has two working chambers arranged coaxially one inside the other, axially variable in length, which can be shortened by evacuation, namely an inner first working chamber or lowering chamber 10 and a larger outer second working chamber or lifting chamber 11 enclosing the first working chamber on all sides.

The first working chamber 10 is bounded at the top by a circular head plate 12 fastened to the end of the rod 4 facing away from the suction cup and at the bottom by a base flange 13 which has a central, axial passage opening through which the rod 4 is passed in a sealed manner. The top plate 12 and the bottom flange 13 are connected by a round bellows 14 made of rubber-like material and form with it an essentially gas-tight wall of the first working chamber. Spacer rings 14 can be provided in the outwardly directed folds of the bellows to prevent the bellows from contracting radially when evacuated. Arranged within the first working chamber is a helical compression spring 16 which surrounds the piston rod 4 and which is supported on the one hand on the upper side of the base flange 13 and on the other hand on the underside of the head plate 12 and is designed with regard to its spring force in such a way that it presses the inner bellows in the event of insufficient vacuum, expanded axially in particular in the first working chamber at ambient pressure. The bottom flange 13 is disposed within a as an axial guide serving for the bottom flange guide sleeve 17, the working unit is fastened by its upper end to the underside of the head flange 18 and having at its lower end an inwardly directed stop shoulder 19, which as a stop for the downward movement the bottom flange 13 is used. A helical compression spring 20 surrounding the inner bellows 14 is supported on the one hand on the underside of the head flange and on the other hand on the upper side of the bottom flange 13 and, in the rest position shown, presses the bottom flange 13 onto the stop shoulder 19 .

The outer or second working chamber 11 is bounded at the top by the head flange 18 , at the bottom by the suction plate 3 and radially by an outer bellows 24 which connects the head flange to the suction plate and the inner working chamber 10 and the compression springs 16 , 20 and the axial guide sleeve 17 encloses and can also be equipped with spacer rings 25 to prevent the radial contraction of the bellows. The outer bellows 24 made of rubber-like material forms the radially outer boundary of the compact work unit.

The work unit can by means of the head flange z. B. on a horizontally movable carrier of a transport device or other suitable location. A central threaded bore 30 of the head flange serves as a pneumatic connection for connecting the work unit to a suitable vacuum generating device 31 , which in the example shown comprises an injector nozzle 32 , which is connected to a compressed air line 34 via a 3/2-way valve 33 with ventilation position. From the pneumatic connection 30 , a first line 35, symbolized by a dot-dash line, leads through the base flange 13 into the interior of the first working chamber 10 . The first line is formed between the flanges 18 , 13 by a flexible plastic hose line, which is guided between the bellows inside the outer bellows. A second line 36 leads from the first working chamber through the piston rod 4 to the suction chamber 7 . The first line and the second line are dimensioned such that the flow resistance of the second line is approximately twice as high as that of the first line 35 , so that when air is drawn out through the first line from the first working chamber, air is also through the second line is sucked in from the outside, but that a gradual evacuation of the first working chamber takes place overall. From the suction chamber 7 shown in the idle state, a third line 37 formed through a through hole in the suction plate leads from below into the interior of the otherwise completely closed and no further connection outer working chamber 11th

In the embodiment shown in FIG. 2, for reasons of clarity, the features corresponding to the features shown in FIG. 1 are designated with the same reference numbers. The differences from the embodiment according to FIG. 1 lie essentially in the structure of the head flange 38 , which in the embodiment according to FIG. 2 has a control valve 41 provided with two pneumatic connections 39 , 40 , the function of which is explained in more detail in connection with FIG. 3. The control valve 41 has a displaceable within a cylindrical transverse bore and sealed against the inner wall of the bore valve body 42 , which separates a first vacuum chamber 43 shown on the left from a second vacuum chamber 44 shown on the right and which, depending on the pressure conditions between the vacuum chambers, the vacuum generation device connectable to the pneumatic connection 40 connects to or disconnects from the first line 35 . A fourth line 45 designed as a vertical flange bore connects the second working chamber to the first vacuum chamber 43 .

The mode of operation of the working unit is first described for the case shown in FIG. 1, in which the first line 35 is connected directly to the injector nozzle 32 for generating negative pressure. At ambient pressure in all chambers, the working unit is in the rest position shown in FIG. 1 and in FIG. 2 (a) with the first working chamber 10 fully expanded and the second working chamber 11 relaxed and in equilibrium. In this state, the suction plate 3 floats above the workpiece 6 at a distance. When switching the directional valve 33 in the open position, compressed air flows into the injector nozzle 32 and creates a vacuum of, for example, -0.8 bar. The inner working chamber 10 is gradually evacuated via the first line 35 , at the same time leakage air is sucked in from the area of the suction chamber 7 into the first working chamber 10 via the line 2 and the vacuum there is partially reduced again. However, since the flow resistance of the second line 36 is approximately twice that of the first line 35 , more air is drawn off per unit of time than can flow in, so that a residual vacuum of, for example, -0.4 bar builds up in the inner working chamber 10 . Since the inner compression spring 16 is designed to be weaker than the outer compression spring 20 , the bottom flange 13 is not pulled upward with increasing negative pressure in the inner working chamber, but the head plate 12 is moved downward with the piston rod 4 located therein. As a result, the suction plate 7 is lowered pneumatically and the outer bellows 24 fixedly connected to the suction plate is stretched ( FIG. 2 (b)). As long as the suction plate is still above the suction surface 5 during the approach phase, the suction chamber 7 is still open and the outer working chamber communicates with the surroundings via the third line, so that air flows into the outer working chamber through this line during axial expansion.

In this way, the suction plate is lowered pneumatically into the mounting position shown in FIG. 2 (b). When the suction plate touches the workpiece, the suction chamber 7 is closed. From this point on, leakage air can no longer flow through the second line into the inner working chamber 10 or ambient air can get into the outer working chamber 11 . If the suction continues to operate, the suction chamber 7 is slowly evacuated through the second line 36 , as a result of which the suction plate 3 sucks firmly onto the suction surface 5 . By closing the suction chamber 7 from the environment, a connection between the second line 36 and the third line 37 is made through the suction chamber 7 simultaneously with the attachment. Via this connection, the outer working chamber 11 is now also evacuated with a time delay, as a result of which the outer bellows contracts. Here, the workpiece firmly adhering to the suction plate is then raised, as shown in Fig. 2 (c). During the lifting, the contracted inner working chamber carried by the base flange 13 then moves upward with the workpiece, this movement being guided through the guide sleeve 17 for the base flange. An increase does not occur if there is no safe suction attack between the suction plate and the workpiece. The workpiece remains securely attached to the suction plate as long as air continues to be extracted.

The described sequence of work strokes of the work unit, in which the suction plate is first lowered by pulling together the first working chamber, then a safe force attack on the workpiece is established by evacuation of the suction chamber and finally the suctioned workpiece is raised by evacuation of the second working chamber or lifting chamber, is achieved solely by Appropriate series connection of the chambers 10 , 7 and 11 predetermined without separate control devices, such as valves, are required to maintain this order.

The schematic pneumatic diagram of FIG. 3 shows a lifting suction device with three identically constructed working units 50 , 51 , 52 , the schematically shown structure of which corresponds to the structure of the embodiment shown in FIG. 2 and which is connected to a common vacuum generating device 53 of the one shown in FIG. 1 Are connected. For reasons of clarity, corresponding features have been given the same reference numbers. In each of the working units, a first control line 54 leads from the first vacuum chamber 43 of the control valve 41 via the pneumatic connection 39 and the pneumatic connection 40 to the second vacuum chamber 44 , in which a spring which prestresses the valve in the open position can be located. In each of the control lines, downstream of the pneumatic connection 39 , there is a check valve 55 which blocks in the direction of the second vacuum chamber 44 . The control lines of all working units are connected to one another by a connecting line 56 , which branches off between the check valve and the second vacuum chamber.

The operation of this group connection of several working units will now be described in the event that the lifting suction device shown is moved to a location in which the first working unit 50 and the second working unit 51 are arranged above a workpiece 6 , while under the third working unit 52 no workpiece lies. Before the work cycle, all control valves 41 are in the open position and all working and pressure chambers are at ambient pressure. The lifting process is initiated by opening the valve 33 of the vacuum generator 53 . The first working chambers 10 are then evacuated through the first lines 35 connected in parallel, as a result of which all the suction plates 3 are lowered. The lowering in the working units 50 , 51 leads to the suction plate resting on the workpiece, as a result of which the suction chamber is closed and the second working chamber or lifting chamber 11 is connected to the vacuum generator 53 . In the third working unit 52 , the lifting chamber 11 remains at ambient pressure since the suction chamber 7 remains open due to the absence of a workpiece.

In the case of the work units in contact with the workpiece, the outer lifting chamber 11 is now evacuated and with it the left evacuation chamber or vacuum chamber 43 of the associated control valve 41 connected via the fourth line 45 . As a result, the valve body 42 of the pulse valve 41 is fixed in the open position. The evacuation of the left vacuum chamber 43 leads to an evacuation of the connected first control line 54 , since the check valve 55 opens in this direction. The vacuum reaches the connecting line 56 and the connected right vacuum chamber 44 with a slight delay. However, the evacuation of the right-hand evacuation chamber in the work units 50 , 51 in contact with the workpiece does not cause the pulse valve to be moved into the blocking position because the opposing left-hand evacuation chamber 43 was previously evacuated. In the right working unit 52 without workpiece contact, the second working chamber 11 cannot be evacuated and therefore, like the left negative pressure chamber 43 connected via the fourth line, remains at ambient pressure. Evacuation via the connecting line 56 and the left vacuum chamber is prevented by the check valve 55 . However, the right vacuum chamber 44 is gradually evacuated via the connecting line 56 , as a result of which the pulse valve 41 , as shown on the right in FIG. 3, is switched into the blocking position. So that the connection of the first working chamber 10 there to the vacuum generator 53 is interrupted, so that the inner return spring 16 of the first working chamber of the working unit 52 pulls the piston there and the suction plate back into the rest position with the suction plate raised. This automatic switching off of the work units of the lifting suction device that are not in the workpiece engagement takes place automatically without separate activation from the outside and enables the vacuum generated by the vacuum generator 53 to be used exclusively by the work units that are actually in the work engagement, thereby enabling energy-saving operation of the device.

The working units 50 , 51 remain switched on until the vacuum generation is terminated by blocking the valve 33 and ventilation of the working units and lowering of the suction plate for depositing the workpiece is initiated. The spring force in the control valves 41 then returns each valve 41 to the open position, if it is not already in the open position.

All in the description, the following claims and The features shown in the drawing can be both individually as well as in any combination with each other be essential to the invention.  

List of reference numbers

1

Lift suction device

2nd

Work unit

3rd

Suction plate

4th

pole

5

Suction surface

6

workpiece

7

Suction chamber

10th

first working chamber

11

second working chamber

12th

Headstock

13

Bottom flange

14

inner bellows

15

Spacer ring

16

inner compression spring

17th

Guide sleeve

18th

Head flange

19th

Stop shoulder

20th

outer compression spring

24th

outer bellows

25th

Spacer rings

30th

Tapped hole

31

Vacuum generation device

32

Injector nozzle

33

3/2-way valve

34

Compressed air line

35

first line

36

second line

37

third line

38

Head flange

39

Pneumatic connection

40

Pneumatic connection

41

Control valve

42

Valve body

43

first vacuum chamber

44

second vacuum chamber

45

fourth line

50

first unit of work

51

second work unit

52

third unit of work

53

Vacuum generation device

54

Control line

55

check valve

56

Connecting line

Claims (20)

1. Lifting suction device for lifting workpieces with suction surfaces, with at least one working unit ( 1 , 50 , 51 , 52 ) for lifting and lowering at least one suction plate ( 3 ), which limits a suction chamber ( 7 ) that can be evacuated when in contact with a suction surface ( 5 ) , characterized in that the working unit ( 1 ; 50 , 51 , 52 ) for lifting a workpiece has at least one working chamber ( 11 ) which can be evacuated by means of a vacuum generation device ( 31 ; 53 ) and which can be evacuated through the suction chamber ( 7 ). 2. Lifting suction device according to claim 1, characterized in that the suction plate is attached to one end of an axially movable rod ( 4 ), that the working unit has at least one first working chamber ( 10 ) which can be evacuated via at least one first line ( 35 ), into which the End of the rod ( 4 ) facing away from the suction plate and leading from the at least one second line ( 36 ) to the suction chamber and that a second working chamber ( 10 ) is provided for lifting the workpiece, said second working chamber ( 10 ) communicating with the suction chamber via at least a third line ( 37 ) communicates. 3. Lifting suction device according to claim 2, characterized in that the first line ( 35 ) is connected to a vacuum generating device ( 31 ; 53 ) which has a injector nozzle ( 32 ) fed by a compressed air source ( 34 ), preferably between the compressed air source ( 34 ) and the injector nozzle ( 32 ) a directional valve ( 33 ) is arranged. 4. Lifting suction device according to one of the preceding claims, characterized in that a lowering movement and a lifting movement of the suction plate ( 3 ) can only be carried out by connecting the working unit, in particular the first line ( 35 ), with a vacuum generating device ( 31 ; 53 ). 5. Lifting suction device according to one of claims 2 to 4, characterized in that the second line ( 36 ) is designed as a throttle line which has a flow resistance that is greater than the flow resistance of the first line ( 35 ), preferably the flow resistance of the first line is between approximately 20% and approximately 80%, in particular between approximately 40% and approximately 60% of the flow resistance of the second line. 6. Lifting suction device according to one of claims 2 to 5, characterized in that the second line ( 36 ) through the rod ( 4 ) from the first working chamber ( 10 ) to the suction chamber ( 7 ) is guided. 7. Lifting suction device according to one of claims 2 to 6, characterized in that the third line ( 37 ) is designed as a bore through the suction plate ( 3 ), preferably with the exception of the third line ( 37 ) no further suction line in the second working chamber ( 11th ) leads. 8. Lifting suction device according to one of claims 2 to 7, characterized in that the first working chamber ( 10 ) within the second working chamber ( 11 ) is arranged, preferably coaxially with the second working chamber ( 11 ). 9. Lifting suction device according to one of the preceding claims, characterized in that the first working chamber ( 10 ) and / or the second working chamber ( 11 ) is enclosed by an axially variable-length bellows, in particular a round bellows ( 14 , 24 ). 10. Lifting suction device according to one of claims 2 to 9, characterized in that an axial guide device ( 17 ) for the first working chamber ( 10 ) is provided, which is designed such that the first working chamber ( 10 ) as a whole is axially movable in the contracted state. 11. Lifting suction device according to one of claims 2 to 10, characterized in that in the first line ( 35 ) between the vacuum generating device ( 53 ) and the first working chamber ( 10 ) at least one control valve ( 41 ) is arranged, which is controlled such that it is kept at negative pressure in the suction chamber (7) and / or in the second working chamber (11) in an open position and switchable at ambient pressure in the suction chamber (7) and / or the second working chamber (11) into a locking position. 12. Lifting suction device according to claims 11, characterized in that the control valve is designed as a pulse valve ( 41 ) and / or that it is pneumatically controllable and / or pneumatically actuated. 13. Lifting suction device according to one of the preceding claims, characterized in that at least a fourth line ( 45 ) from the second working chamber ( 11 ) leads to a pneumatically controllable and / or actuatable control valve ( 41 ), the fourth line preferably to a first vacuum chamber ( 43 ) of the control valve leads. 14. Lifting suction device according to one of claims 11 to 13, characterized in that the control valve ( 41 ) for actuating a valve body ( 43 ) has a first vacuum chamber ( 43 ) and a second vacuum chamber ( 44 ) connected to the second working chamber ( 11 ) , which is connected via a control line ( 54 ) with a check valve ( 55 ) blocking the direction of the second vacuum chamber ( 44 ) and the first vacuum chamber ( 43 ), the control valve ( 41 ) preferably being biased into a passage position and into a blocking position switches when a vacuum is present in the second vacuum chamber ( 44 ) with respect to the first pressure chamber ( 43 ). 15. Lifting suction device according to one of the preceding claims, characterized in that it has several, preferably to a common vacuum generating device ( 53 ) connected, working units ( 50 , 51 , 52 ), the control lines ( 54 ) of the working units via a connecting line ( 56 ) are connected. 16. Method for operating a lifting suction device for Lifting workpieces with suction surfaces, the Lifting suction device for at least one work unit Has at least one suction plate that raises and lowers one that can be evacuated when the suction surface is in contact Suction chamber limited and being the work unit at least one that can be evacuated to lift the workpiece Has working chamber, characterized in that the Working chamber evacuated through the suction chamber becomes. 17. The method according to claim 16, characterized in that the working chamber only through the suction chamber is evacuated through. 18. The method according to claim 16 or 17, characterized characterized in that the work unit for lowering the Suction plates at least one from the second working chamber has a separate, evacuable first working chamber and that the first working chamber automatically before the second Working chamber is evacuated. 19. The method according to claim 17 or 18, characterized characterized in that the suction chamber through the first Working chamber is evacuated. 20. The method according to any one of claims 17 to 19, characterized characterized in that the second working chamber by the is evacuated through the first working chamber.