DE102016204122B4 - Suction holding device and method for operating a suction holding device - Google Patents

Abstract

Suction holding device, comprising at least one suction holding unit (2) having a vacuum channel (7) connected by a shut-off valve (17) in a first vacuum channel section (7a) connected to a vacuum source (4) and one connected to a suction chamber (8) or connectable second vacuum channel portion (7b) is divided, wherein the suction chamber (8) coverable by an object to be held (3) suction opening (22) and in a captured during a Absaugbetriebsen release position of the shut-off valve (17) by means of the vacuum source (4) the vacuum duct (7) can be evacuated, wherein the shut-off valve (17) is switchable to a shut-off position as an alternative to the release position, in which it separates the second vacuum duct section (7b) from the first vacuum duct section (7a) so that the suction effect of the vacuum source (4 ) is interrupted with respect to the suction chamber (8), and with a Druckabgriffsstelle (36) for the tapping of a in the vacuum channel (7) prevailing fluid pressure, characterized in that the suction holding unit (2) connected to the shut-off valve (17) pilot channel (26) into which a pneumatic control pressure medium can be fed, through which the shut-off valve (17) from the release position in the shut-off position is switched, wherein in the course of the pilot channel (26) depending on the height of the at the Druckabgriffsstelle (36) in the vacuum channel (7) prevailing fluid pressure actuable pilot valve (31) is turned on, from a pilot channel (26 ) for the passage of the pneumatic control pressure-releasing open position in a pilot channel (26) shut-off closed position is switchable when the at the Druckabgriffsstelle (36) prevailing fluid pressure has dropped at least to a predetermined or predetermined minimum vacuum value.

Description

The invention relates to a Saughaltevorrichtung, comprising at least one Saughalteeinheit having a vacuum channel which is divided by a shut-off valve connected to a vacuum source or connectable first vacuum duct section and connected to a suction chamber or connectable second vacuum duct section, wherein the suction chamber by a festzuhaltenden Subject has coverable suction port and in a captured during a Absaugbetriebsphase release position of the check valve is evacuated by the vacuum source through the vacuum channel through, the check valve is switched alternatively to the release position in a shut-off position in which it separates the second vacuum duct section from the first vacuum duct section, so the suction effect of the vacuum source is interrupted with respect to the suction chamber, and with a Druckabgriffsstelle for tapping a pressure prevailing in the vacuum channel fluid pressure.

The invention further relates to a method of operating a suction holding device having at least one suction holding unit having a vacuum channel which is divided by a shut-off valve into a first vacuum channel portion connected to a vacuum source and a second vacuum channel portion connected or connectable to a suction chamber. wherein the suction chamber has a coverable by an object to be held suction opening and in a Absaugbetriebsphase a release position einnehmendem shut-off valve by the vacuum source through the vacuum channel is evacuated through, the shut-off valve is alternatively switched to the release position in a shut-off, in which it the second vacuum channel section of the first vacuum duct section so that the suction effect of the vacuum source is interrupted with respect to the suction chamber, and wherein during the Absaugbetriebsphase the in the vacuum duct on a pressure tap prevailing fluid pressure is tapped.

A trained in the aforementioned sense and operable suction holding device is from the DE 101 40 248 A1 where it has a Flachsauggreifer, which is connected via a vacuum channel to a vacuum generator. In the course of the vacuum channel, a solenoid valve and a pressure sensor are turned on, wherein the data determined by the pressure sensor are processed in an evaluation and the control of the solenoid valve takes place in dependence on the data of the pressure sensor.

One from the DE 198 47 314 A1 known suction holding device is used for gripping and holding objects and has a suction cup, in which a suction chamber is formed, which has a coverable by an object to be fixed suction opening. To the suction chamber, a vacuum channel is connected, which is connected to a vacuum source, which can cause an evacuation of the suction chamber during a Absaugbetriebsphase to hold the attached to the suction opening object by means of negative pressure. In the course of the vacuum channel, a shut-off valve is switched on, which can take either the Absaugbetriebsphase enabling release position or a vacuum channel and thus the Absaugbetriebsphase interrupting shut-off. Switching from the shut-off position to the release position is tactile by the application of an actuating member of the shut-off valve on the part of the object to be held. During operation of the known suction-holding device, it may happen that an object attached to the suction cup does not completely close the suction opening and yet causes the shut-off valve to be switched to the release position, so that a suction operating phase connected to a not inconsiderable energy consumption is initiated, without any associated holding effect would.

From the DE 38 10 989 C2 a handling device is known, which is equipped with a suction device to hold objects by means of negative pressure can. The suction device has a connected to a vacuum source vacuum channel, in the course of which a valve member is turned on, which is positionable depending on the pressure difference at him in the vacuum channel releasing open position or in a flow cross-section of the vacuum channel reducing working position. The working position is present when no object is sucked on the suction device. In order to ensure the functionality of the valve member, no shut-off position can be realized in this suction, in which the fluid passage is completely prevented by the vacuum channel.

The invention has for its object to provide a reliable and yet energy efficient working suction holding device and a method for operating such a suction holding device.

To achieve this object, it is provided in connection with a suction holding device of the type mentioned that the suction holding unit has a pilot channel connected to the shut-off valve, in which a pneumatic control pressure medium can be fed, through which the shut-off valve from the release position to the shut-off can be switched, wherein in the course of the pilot channel a dependent on the height of the prevailing at the Druckabgriffsstelle in the vacuum channel fluid pressure controllable pilot valve is switched, which is switchable from a pilot channel for the passage of the pneumatic control pressure-releasing open position into a shut-off the pilot passage closed position, when the prevailing at the Druckabgriffsstelle fluid pressure has dropped at least to a predetermined or predeterminable minimum negative pressure value.

In this way, energy-efficient operation of the suction holding device is possible because the suction of a vacuum chamber connected to the suction chamber can be stopped with technically simple means when the suction port of the suction chamber is not or only partially covered by an object. The associated interruption of the Absaugbetriebsphase is controlled on the basis of the prevailing in the pilot passage fluid pressure, wherein the shut-off valve is switched by a feedable pneumatic control pressure medium in the shut-off position, when the prevailing in the pilot passage fluid pressure does not have a characteristic for the suction and holding of an object minimum Low pressure value has reached or fallen below. When the fluid pressure in the pilot channel properly decreases to a minimum negative pressure value during the exhaust operation phase, a pilot valve is closed which influences the fluid passage through a pilot channel drivingly communicating with the shut-off valve and into the pneumatic control pressure medium required to switch the shut-off valve to the shut-off position can be fed. If the pilot valve, due to the construction of the minimum negative pressure value, is switched to a shut-off position in the pilot control channel, the pneumatic control pressure medium fed into the pilot control channel can no longer exert any drive force on the shut-off valve, so that the same remains in the open position to ensure an undisturbed suction operating phase and reliable operation To ensure retention of an object covering the suction opening. The suction holding device works particularly effectively when it is equipped with a plurality of suction holding units operated in parallel in order to keep an object at the same time under pressure by means of a plurality of suction chambers, since a suction operating phase is maintained here with little technical effort only with respect to those suction chambers which are actually completely covered by the object to be held are. The suction holding device can be realized cost-effectively without electrical sensors and without tactile detection measures and thus very cost-effectively. If the Absaugbetriebsphase interrupted due to a not completely closed suction, there is a through the shut-off valve to the atmosphere sealed system, which has virtually no leakage, which promotes energy-saving operation.

Advantageous developments of the invention will become apparent from the dependent claims.

The Druckabgriffsstelle for the required for the actuation of the pilot valve fluid pressure is expediently in the leading to the suction chamber second vacuum channel portion of the vacuum channel. This ensures that the pilot valve does not switch to the closed position when the shut-off valve has been switched to the shut-off position due to a negative pressure which does not build up in the vacuum channel through the fed-in pneumatic control pressure medium. However, in principle it is quite possible to lay the Druckabgriffsstelle in the first vacuum channel section. Since in this case, the pilot valve with active vacuum source also switches to the closed position, when the shut-off valve switches to the shut-off, it requires to reset to the initial state of appropriate measures to cancel the pressure prevailing in the first vacuum duct section negative pressure again, for example, means a conscious Allow venting of the first vacuum channel section.

The suction holding device can be realized in a particularly simple and cost-effective manner if the fluid pressure prevailing at the pressure tapping point is connected directly to the pilot valve as the actuating pressure, which causes the switching operation between the open position and the closed position. In particular, the pilot valve may have a drive surface movable to initiate the switching operation, which is constantly exposed to the fluid pressure prevailing at the pressure tap of the vacuum channel, for example by means of a pressure tap channel connecting the pilot valve to the pressure tap of the vacuum channel, separate from the vacuum channel.

The pilot valve is expediently of the type "normally open" and biased by spring means in its open position. The tapped at the Druckabgriffsstelle fluid pressure acts on a drive surface of the pilot valve, which is oriented opposite to the effective direction of the spring means. As a result, a negative pressure building up in the vacuum channel can act on the drive surface and cause a negative pressure force which overcomes the actuating force of the spring means and switches the pilot valve counter to the actuating force of the spring means into the closed position.

The pilot valve is preferably a 2/2-way valve. Such a two-way valve has expediently a movable to switch the pilot valve between two switching positions valve member which is coupled to a drive surface which is constantly acted upon by the tapped at the Druckabgriffsstelle the vacuum channel fluid pressure.

The check valve is preferably of a "normally open" type. It is biased by spring means in the release position, the action of which is opposite to a switch from the release position in the shut-off driving force resulting from the application of a drive surface of the shut-off valve with the feed through the pilot channel pneumatic control pressure medium. If the pilot channel during the Absaugbetriebsphase switched by the building up in the vacuum channel vacuum in the closed position, a subsequently fed into the pilot duct pneumatic control pressure medium can no longer reach the drive surface of the check valve, so this remains due to the still effective spring means in the release position.

The suction holding device expediently has a vacuum source connected to the first vacuum channel section, to which a control means is assigned for its selective activation or deactivation. The vacuum source is preferably an ejector device operating on the principle of a jet pump, which is supplied with compressed air, wherein the operating state of the ejector device depends on whether momentarily a supply of compressed air takes place or not. The latter can be suitably controlled by means of a control valve device of the suction holder. Such equipped suction holding device works energetically particularly efficient, because the vacuum source in times when no Absaugbetriebsphase is needed, can be deactivated.

The suction holding device is preferably designed so that the pilot channel is fed in a controlled manner with the pneumatic control pressure medium. Thus, there is the possibility of selectively inducing or preventing the feeding process of the pneumatic control pressure medium. This is expediently carried out by means of a control valve device which is switched on in the connection between the pilot control channel and a control pressure source providing the pneumatic control pressure medium.

A particularly conveniently operated suction holding device has an electronic control device, by means of which the feeding of the pneumatic control pressure medium into the pilot channel by means of a triggered control signal can be caused, wherein the triggered control signal is in particular an electrical signal. The triggered control signal is generated in particular delayed in time after the beginning of the Absaugbetriebsphase. This ensures that, when the suction opening is completely closed, it is possible to build up a minimum negative pressure value that causes the pilot valve to switch to the closed position before the shut-off valve is acted on by the pneumatic control pressure medium and switched to the shut-off position.

In particular, measures are taken in the suction holding device, which only cause the feeding of the pneumatic control pressure medium in the pilot channel, if during the Absaugbetriebsphase with properly closed suction opening would be expected to reach the minimum negative pressure value. This can be determined empirically based on previous measurements.

To generate the triggered control signal, the suction-holding device contains, for example, a time-switching device and / or a detection device that responds to the object to be held.

The suction holding unit expediently has a housing in which the vacuum channel and the pilot channel are formed and on which at least one flexible suction cup defining the suction chamber is arranged. The housing also preferably carries the shut-off valve and the pilot valve.

The problem underlying the invention is achieved in connection with an initially mentioned method for operating a suction holding device in that the tapped at the Druckabgriffsstelle fluid pressure is used directly for actuating a pilot valve, by which the switching position of the shut-off valve can be predetermined, wherein the pilot valve is designed in that it is switched into a closed position preventing the switching of the shut-off valve into the shut-off position when the fluid pressure tapped in the vacuum channel has dropped to at least a predetermined or predefinable minimum negative pressure value.

When operating the suction holding device by means of the pilot valve advantageously a pilot channel is controlled, through which the shut-off valve, a pneumatic control pressure medium can be supplied, by the switching of the shut-off valve from the release position in the shut-off is hervorufbar, the Pilot duct is closed by the pilot valve when the tapped in the vacuum duct fluid pressure has dropped at least to a predetermined or predeterminable minimum negative pressure, so that a subsequent switching of the shut-off valve is prevented by the fed into the pilot control pneumatic control pressure medium.

The suitable for switching the shut-off valve in the shut-off pneumatic control pressure medium is expediently caused delayed with respect to the start time of the Absaugbetriebsphase. This ensures that a sufficiently long period of time is available to ensure the establishment of the minimum negative pressure value and the closing of the pilot valve before the pneumatic control pressure medium is supplied to the shut-off valve.

The invention will be explained in more detail with reference to the accompanying drawings. In this show:

1 a circuit diagram of a suction holding device according to the invention preferred structure,

2 in the 1 Suction holding unit of the suction holding device shown in dashed lines in a schematic, but with respect 1 representational representation, wherein a deactivated basic position is shown

3 the arrangement 2 during the Absaugbetriebsphase in the sucked and detained state of an object, and

4 the arrangement 2 in the partially covered state of the suction opening and, accordingly, canceled Absaugbetriebsphase with shut off by the shut-off valve vacuum channel.

The total in the drawing with reference numeral 1 designated suction holding device has at least one suction holding unit 2 that is designed to handle any object 3 hold by means of negative pressure and after a certain holding period, which is preferably freely selectable, let go again. In a preferred application that applies to the embodiment, the suction holding device 1 used as a suction gripping device, in which at least one suction-holding unit 2 by means of a not shown positioning relative to the object to be held 3 is movable and active to the object 3 is attachable to take the latter by means of negative pressure. Subsequently, the suction holding unit 2 be moved by means of the positioning in space to the object 3 reposition and place in another place again.

Contains the suction holder 1 several suction holding units 2 , several or all suction holding units 2 be arranged together on one and the same positioning device or in each case at a separate positioning device.

Several suction holding units 2 are expediently combined to form a uniformly handled suction holding unit group, wherein they are used together at the same time to a large-area object 3 hold.

In the drawing, only one suction holding unit 2 fully mapped, while optional further suction holding units 2 are only indicated. The suction holder 1 can also easily via only a single Saughalteeinheit 2 feature.

Grasping and holding the object 3 is effected by negative pressure, by a vacuum source 4 provided. A control means is preferred 5 present, with which the operating state of the vacuum source 4 pretend and that is particularly suitable, the vacuum source 4 alternatively to activate or deactivate. The vacuum source 4 has a suction connection 6 , at which with active vacuum source 4 a suction effect is due to which one with the interposition of a vacuum channel 7 connected suction chamber 8th is evacuable.

At the vacuum source 4 The exemplary embodiment is an ejector device which operates in a manner comparable to a jet pump 4a , It has an input connection 12 , with the interposition of the tax means 5 , which in this case is an electrically actuated control valve device 5a is connected to a pressure source "P", which is preferably a compressed air source. The ejector device 4a also has an outlet communicating with the atmosphere "R" 13 , On at the input port 12 fed pressure medium flows through an internal suction nozzle 14 and enters the outlet 13 to the atmosphere, with the suction nozzle 14 at the suction connection 6 causes the already mentioned suction effect.

Depending on the operating state of the control valve device 5a is the pressure source "P" either to activate the vacuum source 4 with the input connector 12 connected or to deactivate the vacuum source 4 from the input terminal 12 separated. The operating state of the control valve device 5a is suitably by an electronic control device 15 specifiable, which expediently forms part of the suction-holding device 1 is, which is preferred also for the vacuum source 4 and the control means 5 or the control valve device 5a applies.

The suction holding unit 2 has a housing indicated by dashed lines 16 that from the vacuum channel 7 is interspersed. One in the course of the vacuum channel 7 switched on shut-off valve 17 divides the vacuum channel 7 in a first vacuum channel section 7a and a second vacuum channel section 7b , The first vacuum channel section 7a is to the suction connection 6 the vacuum source 4 connected, the second vacuum channel section 7b to the already mentioned suction chamber 8th preferably in at least one flexible suction cup 18 is formed, which expediently on the housing 16 is attached.

The suction chamber 8th is above a suction opening 22 in contact with the atmosphere. At the suction opening 22 it is in particular an opening of the suction cup 18 ,

To an object 3 to grab and hold, will be the suction opening 22 and the object 3 relative to each other so positioned that the object 3 the suction opening 22 completely covers and thus closes, as in the 1 and 3 is indicated. During a suction operation phase of the suction holding device 1 takes the shut-off valve 17 one out 1 to 3 apparent release position in which it passes the fluid through the vacuum channel 7 through which releases through the object 3 closed suction chamber 8th by means of the active vacuum source 4 is evacuated and the object 3 because of this in the vacuum channel 7 and in the suction chamber 8th generated negative pressure is recorded.

The removal of a previously seized object 3 is thereby provable that the suction chamber 8th is ventilated. For this purpose, the deactivation of the vacuum source is sufficient in the embodiment 4 , because in this case the suction connection 6 through the ejector device 4a through communicating with the atmosphere "R". Alternatively or additionally, it is possible, the suction holder 1 equip with means that make it possible to use the vacuum channel 7 To pressurize with overpressure and thereby generate a so-called ejection pulse through which the object 3 active from the suction opening 22 is dropped.

The shut-off valve 17 can alternatively to the release position in an in 4 illustrated shut-off be switched. In this shut-off position is a fluid passage through the vacuum channel 7 excluded. The first vacuum channel section 7a is then from the second vacuum channel section 7b separated fluid-tight.

Preferably, the shut-off valve 17 designed as a 2/2-way valve.

It is advantageous if the shut-off valve 17 a monostable valve is by spring means 23 is biased into a basic position, which is the release position. Switching into the shut-off position and holding in this shut-off position can be caused by a drive surface 24 the shut-off valve 17 is acted upon by a pneumatic control pressure medium from which a driving force results, the spring force of the spring means 23 is opposite and which is greater than the spring force of this spring means 23 , When the drive surface 24 is not acted upon by the pneumatic control pressure medium, takes the shut-off valve 17 the release position or returns to this release position.

The drive surface 24 is on a movable valve member 25 the shut-off valve 17 trained in that 4 is illustrated schematically.

During the shut-off position of the shut-off valve 17 is the suction effect of the vacuum source 4 with respect to the suction chamber 8th regardless of whether the vacuum source interrupted 4 is active or not.

That for generating the on the shut-off valve 17 acting driving force required pneumatic control pressure medium is the shut-off valve 17 through one as pilot channel 26 designated fluid channel of the suction holding unit 2 can be fed through. The pilot channel 26 has a feed section 26a , which is connectable to a control pressure source, which is exemplarily in an advantageous manner with the pressure source "P" is identical, but in principle could also be a separate pressure source in this regard. In the connection between the feed section 26a and the control pressure source "P" is a control valve device 27 turned on, for better distinction from that of the vacuum source 4 associated control valve device 5a in the following also as the second control valve device 27 referred to as. This second control valve device 27 can alternatively be positioned in each one of two switching positions, which are on the one hand to a in 1 illustrated venting position and on the other hand is a ventilation position. In the ventilation position, the second control valve device provides 27 for a continuous fluid connection between the feed section 26a and the control pressure source "P", so that pneumatic control pressure medium in the feed section 26a the pilot channel 26 is fed. In the venting position is the feed section 26a separated from the control pressure source "P" and instead connected to the atmosphere "R", so that the feed section 26a the pilot channel 26 vented and thus depressurized.

Both control valve devices 5a . 27 are expediently designed to be electrically actuated and to the already mentioned electronic control device 15 connected, by the operating state of both control valve devices 5a . 27 can be specified. This is indicated in the drawing by dashed arrow lines.

In the course of the pilot channel 26 is a pilot valve 31 turned on, can be determined by the function of its switching position, whether that the feed section 26a supplied pneumatic control pressure medium is capable of acting on the shut-off valve 17 to act to switch this to the shut-off position.

The pilot valve 31 divides the pilot channel 26 in the already mentioned feed section 26a and in one to the shut-off valve 17 connected operating section 26b , The actuating section preferably opens 26b in a drive chamber 32 the shut-off valve 17 coming from the moving drive surface 24 is limited.

Preferably, it is the pilot valve 31 around a 2/2-way valve. The pilot valve 31 is optional in one 1 . 2 and 4 apparent open position or in one 3 apparent closed position positionable. In the open position, the fluid passage through the pilot channel 26 released and the feed section 26a communicates with the operating section 26b , In the closed position is the channel profile of the pilot channel 26 interrupted and the feed section 26a from the operating section 26b separated.

At the pilot valve 31 it is expediently a monostable valve by spring means 33 is biased into a basic position, which is the open position.

The pilot valve 31 has a movable drive surface 34 on, opposite to the effective direction of the associated spring means 33 is oriented. This means that one on this drive surface 34 Pending negative pressure quasi a pulling force on the pilot valve 31 exercises and then seeks the pilot valve 31 against the force of the spring means 33 to switch to the closed position.

The pilot valve 31 is switchable to the closed position and retained in the closed position when on the drive surface 34 acting a negative pressure, which has a certain minimum height, which is referred to below as the minimum negative pressure value. Once on the drive surface 34 acting fluid pressure, which is also referred to as the actuating pressure for better distinction below, is a predetermined minimum value having negative pressure, so is a pressure lying below the atmospheric pressure by a predetermined amount, finds the switching of the pilot valve 31 from the previously occupied open position in the closed position instead.

To the pilot valve 31 to be able to switch on the actuating pressure is the pilot valve 31 via a pressure tap channel 35 at a pressure tap 36 to the vacuum channel 7 connected. This means that the drive surface 34 the pilot valve 31 is always exposed to the same fluid pressure at the Druckabgriffsstelle 36 in the vacuum channel 26 prevails.

In a preferred concrete implementation has the pilot valve 31 a switchable between the closed position and the open position valve member 37 on which the drive surface 34 is formed and that with respect to the housing 16 movable drive surface 34 an actuation chamber 38 limited, in which the pressure tap channel 35 with its the pressure tap 36 opposite end portion opens. In conjunction with the above explanations, it can thus be seen that the pilot valve 31 as long as the basic position forming open position occupies, as at the Druckabgriffsstelle 36 prevailing fluid pressure has not reached the minimum negative pressure value yet. But as soon as the at the pressure tap 36 prevailing fluid pressure has dropped to the minimum negative pressure value, the pilot valve switches 31 from the open position to the closed position and keeps this closed position until the actuation pressure has risen again above the minimum negative pressure value.

The said minimum negative pressure value is by appropriate interpretation of the spring force of the spring means 33 and the size of the drive surface 34 given or can be specified by varying these sizes to the desired height.

Because that at the Druckabgriffsstelle 36 prevailing fluid pressure the pilot valve 31 switched directly as the switching operation inducing operating pressure, unnecessary electrical detection and / or operating measures to obtain the desired switching function. Thus, the suction holder can be realized very inexpensively.

Although the pressure tap 36 at any position within the vacuum channel 7 could be positioned, it is called considered advantageous when, according to the embodiment in which the suction chamber 8th leading second vacuum channel section 7b located. This placement has the advantage of being at the Druckabgriffsstelle 36 can not form a vacuum when the vacuum source 4 activated and the shut-off valve is switched to the shut-off position.

Hereinafter, a mode of operation of the suction-holding device considered to be particularly advantageous 1 described.

One for grasping an object 3 serving process begins with the 2 apparent deactivated basic position in which the vacuum source 4 inactive and the feed section 26a the pilot channel 26 is vented. As a result, the vacuum channel prevails 7 and in the pilot channel 26 Atmospheric pressure, so that the shut-off valve assumes the release position and the pilot valve assumes the open position.

Following this is the object to be recorded 3 on the suction cup 18 positioned so that the suction opening 22 is closed. At the same time or even before or after is by means of the electronic control device 15 the vacuum source 4 activated so that the in 3 illustrated Absaugbetriebsphase takes place. Thereby the vacuum channel becomes 7 and the suction chamber 8th evacuated and the object 3 is due to the negative pressure generated at the sealed through him suction opening 22 recorded.

While the vacuum in the vacuum channel 7 builds up, remains the pilot valve 31 in the open position. The pilot channel remains 26 initially deaerated on the input side by the second control valve device 27 , as already during the deactivated basic position of the 2 , is held in the vent position.

The suction holder 1 However, it is designed so that the pilot channel 26 is vented when after the attachment of the article 3 to the suction opening 22 a certain period of time has passed, which is known as the period of The venting is done by way of example by switching the second control valve device 27 in the ventilation position.

The delay period is sufficiently long to assure that it is properly received by an item 3 covered suction opening 22 the minimum negative pressure value in the vacuum channel 7 can build up. In any case, this minimum negative pressure value is a sufficiently high negative pressure in order to keep the item under pressure due to negative pressure 3 to guarantee.

To ensure this process, the switching of the second control valve device 27 in the ventilation position preferably by means of the electronic control device 15 triggered triggering signal. This triggering is exemplified by a to the electronic control device 15 belonging time switching device 42 causes the delay period is stored.

For example, the delay period begins to run with the start of the Absaugbetriebsphase, or even after using a not further shown detection device, a certain relative position between the suction port 22 and the object to be captured was detected.

Is the suction opening 22 properly closed, builds in the vacuum channel 7 the minimum negative pressure value before the second control valve device 27 receives the switching to the ventilation position causing electrical control signal.

When the minimum negative pressure value is reached, the pilot valve switches 31 in the out 3 apparent closed position, so that the connection between the feed section 26a and the operation section 26b the pilot channel 26 is interrupted. If now afterwards the ventilation of the feed section 26a happens, this affects the switching position of the shut-off valve 17 not so that remains unchanged in the release position, so that the Absaugbetriebsphase is continuously active.

To subsequently deposit the object 3 becomes in the manner already mentioned above the vacuum channel 7 vented so that at the pressure tap 36 prevailing fluid pressure in the short term rises to at least the atmospheric pressure, which is a switching back of the pilot valve 31 into the open position entails.

Conveniently, the vacuum channel 7 already vented on the input side at this time, by the second control valve device in the embodiment 27 was switched back to the vent position. This switching back to the venting position is particularly due to the deactivation of the vacuum source 4 coupled. This ensures that the shut-off valve 17 is not undesirably moved into the closed position after completion of the Absaugbetriebsphase.

The 4 shows an operating state after initiation of the Absaugbetriebsphase in a case where the suction port 22 by an object to be held 3 not or not completely closed. It may well be that the object 3 in one with several suction holding units 2 equipped suction holder 1 by other Saughalteeinheiten located in the Absaugbetriebsphase 2 is held. Anyway, the missing cover would have the suction opening 22 without any protective measures that result through the vacuum channel 7 A suction would take place which would be ineffective and consequently would result in unnecessary energy consumption.

In the illustrated suction holder 1 has not completely closed the suction opening 22 The result is that at the Druckabgriffsstelle 36 prevailing fluid pressure does not drop to the minimum negative pressure, so the pilot valve 31 remains positioned in the open position. Consequently, the pneumatic control pressure medium, the time delay after initiation of the Absaugbetriebsphase in the feed section 26a the pilot channel 26 is fed, unhindered to the shut-off valve 17 and pour this into the in 4 Switch over the illustrated shut-off position. This is still due to the active vacuum source 4 acted first vacuum channel section 7a from the second vacuum channel section 7b and the suction chamber 8th separated fluid-tight and it can not be ambient air through the suction chamber 8th through into the first vacuum channel section 7a overflow. This reduces the air and energy consumption.

Will the suction holder 1 then deactivated again, finds a vent of the pilot channel 26 instead, so the shut-off valve 17 returns to the release position and can again join a Absaugbetriebsphase.

Claims (17)

Suction holding device, with at least one suction holding unit ( 2 ), which has a vacuum channel ( 7 ), which by a shut-off valve ( 17 ) in one with a vacuum source ( 4 ) connected or connectable first vacuum channel section ( 7a ) and one with a suction chamber ( 8th ) connected or connectable second vacuum channel section ( 7b ), wherein the suction chamber ( 8th ) an object to be held ( 3 ) coverable suction opening ( 22 ) and in an assumed during a Absaugbetriebsen release position of the shut-off valve ( 17 ) by means of the vacuum source ( 4 ) through the vacuum channel ( 7 ) is evacuated through, with the shut-off valve ( 17 ) is switchable to a shut-off position as an alternative to the release position, in which it the second vacuum channel section ( 7b ) from the first vacuum channel section ( 7a ), so that the suction effect of the vacuum source ( 4 ) with respect to the suction chamber ( 8th ) is interrupted, and with a pressure tap point ( 36 ) for tapping one in the vacuum channel ( 7 ) prevailing fluid pressure, characterized in that the suction holding unit ( 2 ) one to the shut-off valve ( 17 ) connected pilot channel ( 26 ), in which a pneumatic control pressure medium can be fed, through which the shut-off valve ( 17 ) is switched from the release position into the shut-off position, wherein in the course of the pilot channel ( 26 ) depending on the height of the pressure tap ( 36 ) in the vacuum channel ( 7 ) controllable fluid pressure actuable pilot valve ( 31 ) is switched on, the one from the pilot channel ( 26 ) for the passage of the pneumatic control pressure medium releasing open position in a pilot channel ( 26 ) shut-off closed position is switchable when the at the pressure tap point ( 36 ) prevailing fluid pressure has dropped at least to a predetermined or predeterminable minimum negative pressure value. Suction holding device according to claim 1, characterized in that the pressure tapping point ( 36 ) in which to the suction chamber ( 8th ) leading second vacuum channel section ( 7b ) is located. Suction holding device according to claim 1 or 2, characterized in that at the Druckabgriffsstelle ( 36 ) prevailing fluid pressure the pilot valve ( 31 ) is switched directly as the switching operation between the open position and the closed position causing actuating pressure. Suction holding device according to one of claims 1 to 3, characterized in that the pilot valve ( 31 ) via a for switching the pilot valve ( 31 ) movable drive surface ( 34 ), which is constantly at the pressure tap point ( 36 ) of the vacuum channel ( 7 ) is exposed to prevailing fluid pressure. Suction holding device according to one of claims 1 to 4, characterized in that the pilot valve ( 31 ) for receiving at the pressure tap point ( 36 ) in the vacuum channel ( 7 ) prevailing fluid pressure via a pressure tap channel ( 35 ) fluidly to the vacuum channel ( 7 ) connected. Suction holding device according to claim 4 or claim 4 and claim 5, characterized in that the pilot valve ( 31 ) by spring means ( 33 ) is biased in the open position, wherein by the at the Druckabgriffsstelle ( 36 ) tapped fluid pressure actuable drive surface ( 34 ) of the pilot valve ( 31 ) opposite to the effective direction of the spring means ( 33 ) is oriented. Suction holding device according to one of claims 1 to 6, characterized in that the pilot valve ( 31 ) is a 2/2-way valve. Suction holding device according to one of claims 1 to 7, characterized in that the shut-off valve ( 17 ) in the release position by spring means ( 23 ) is biased, the action of which is opposite to a switching from the release position to the blocking position causing driving force, from the application of a driving surface ( 24 ) of the shut-off valve ( 17 ) with the through the pilot channel ( 26 ) is fed through pneumatic control pressure medium. Suction holding device according to one of claims 1 to 8, characterized in that it is attached to the first vacuum channel section ( 7a ) connected vacuum source ( 4 ) which, for its selective activation or deactivation, comprises a control means ( 5 ), wherein the vacuum source ( 4 ) expediently around an ejector device which can be operated with compressed air ( 4a ) and the control means ( 5 ) about a compressed air supply controlling, electrically operated control valve device ( 5a ). Suction holding device according to one of claims 1 to 9, characterized in that it is connected to the pilot channel ( 26 ) connected, for selectively switching on or off the pneumatic control pressure medium trained control valve device ( 27 ) contains. Suction holding device according to one of claims 1 to 10, characterized in that it comprises an electronic control device ( 15 ), by which the feeding of the pneumatic control pressure medium in the pilot channel ( 26 ) can be brought about by means of a triggered control signal. Suction holding device according to claim 11, characterized in that the electronic control device ( 15 ) is configured to generate the triggered control signal delayed in time after the beginning of the Absaugbetriebsphase. Suction holding device according to claim 11 or 12, characterized in that it comprises a time-switching device (12) for generating the triggered control signal ( 42 ) and / or has a responsive to the object to be held responsive detection device. Suction holding device according to one of claims 1 to 13, characterized in that the suction holding unit ( 2 ) a housing ( 16 ), in which the vacuum channel ( 7 ) and the pilot channel ( 26 ) are formed and at least one of the suction chamber ( 8th ) defining flexible suction cup ( 18 ) is arranged. Method for operating a suction-holding device, which via at least one suction-holding unit ( 2 ), which has a vacuum channel ( 7 ), which by a shut-off valve ( 17 ) in one with a vacuum source ( 4 ) connected or connectable first vacuum channel section ( 7a ) and one with a suction chamber ( 8th ) connected or connectable second vacuum channel section ( 7b ), wherein the suction chamber ( 8th ) an object to be held ( 3 ) coverable suction opening ( 22 ) and in a release position einnehmendem during a Absaugbetriebsphase stop valve ( 17 ) by means of the vacuum source ( 4 ) through the vacuum channel ( 7 ) is evacuated through, with the shut-off valve ( 17 ) is switchable to a shut-off position as an alternative to the release position, in which it the second vacuum channel section ( 7b ) from the first vacuum channel section ( 7a ), so that the suction effect of the vacuum source ( 4 ) with respect to the suction chamber ( 8th ) is interrupted, and wherein during the Absaugbetriebsphase the in the vacuum channel ( 7 ) at a pressure tap point ( 36 ) prevailing fluid pressure is tapped, characterized in that at the Druckabgriffsstelle ( 36 ) tapped fluid pressure immediately to actuate a pilot valve ( 31 ) is used, by the switching position of the shut-off valve ( 17 ), whereby the pilot valve ( 31 ) is designed so that it is in a the switching of the shut-off valve ( 17 ) in the shut-off preventing closing position is switched when in the vacuum channel ( 7 ) tapped fluid pressure has dropped at least to a predetermined or predeterminable minimum negative pressure value. A method according to claim 15, characterized in that by means of the pilot valve ( 31 ) a pilot channel ( 26 ), through which the shut-off valve ( 17 ) is fed to a pneumatic control pressure medium, by switching the shut-off valve ( 17 ) can be brought out of the release position into the shut-off position, whereby the pilot channel ( 26 ) through the pilot valve ( 31 ) is closed when in the vacuum channel ( 7 ) tapped fluid pressure has dropped at least to a predetermined or predeterminable minimum negative pressure value, so that a subsequent switching of the shut-off valve ( 17 ) into the pilot channel ( 26 ) fed pneumatic control pressure medium is prevented. A method according to claim 16, characterized in that the pneumatic control pressure medium based on the initiation of Absaugbetriebsphase delayed in time in the pilot channel ( 26 ) is fed.

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