EP3087022B1 - Work device - Google Patents

Description

The invention relates to a working device, comprising a suitable for actuating a fluid-operated drive means actuator having a working valve which is controlled by a generated based on a pneumatic control pressure control signal and which contains a pneumatic control pressure supplying control device to their manual operation with a is equipped with a movable manual actuating means and has a pneumatic control pressure providing control output.

From the DE 20111435 U1 is designed as a lifting device working device of the aforementioned type, with which it is possible to raise and lower a umzupositionierenden object with little effort and also to position as long as desired at any desired height level. Responsible for the lifting movement is designed in the manner of a working cylinder drive means which is equipped with a variable volume drive chamber, which can be acted upon by a drive fluid which is provided in the amount of secondary pressure at a secondary port of a pressure control valve. The secondary pressure is maintained at a constant level by the pressure regulator, but may be temporarily varied up or down to vary the volume of the drive chamber and thus the height position of the article. This temporary change of the secondary pressure can be effected by a control device connected to the pressure regulating valve, which can be manually operated by means of a movable manual operating means and serves to connect a pressure control to a pneumatic control pressure acting on the secondary pressure. The pneumatic control pressure is provided by an external control pressure source, which is alternatively connectable to the atmosphere with a control input of the pressure control valve. The control means allows by means of the movable manual actuating means an optional connection of the control input of the pressure regulator with either the external one Control pressure source or the atmosphere to temporarily detune the pressure control valve so that it causes either a supply or a discharge of drive fluid with respect to the drive chamber of the drive device. A disadvantage of the known working device is that due to the quasi-digital control of the pressure control valve, a sensitive handling of an object is hardly possible.

From the EP 0361162 A2 is a manipulator known, which has a force-controlled control. A force transducer detects the manual force applied by the operator to a hand lever, which is then converted into an electrical voltage signal, on the basis of which a drive device of the manipulator is actuated. In such a system, a relatively high effort is required to exclude a functional impairment due to environmental influences. Also, this control system has a significant energy consumption.

The DE 198 01 839 A1 deals with a device for generating a counterweight force in a manipulator. A load to be manipulated is here movable via a gearbox and can be balanced by means of a pressure-medium-operated drive generating a counterweight force.

The invention has for its object to provide a working device of the type mentioned above, which allows a simple design, an energy-saving, reliable and sensitive manual operation.

To achieve this object, it is provided in connection with the features mentioned above that the actuating device has a closed pneumatic cavity system providing the control pressure, to which a volume-variable control chamber of the control device connected to the control output belongs, whose volume is continuously variable with the result of a continuously variable change in the control pressure by manually moving the manual actuating means.

In this way, the control device is designed to generate a continuously variable control pressure. Compressed air trapped in the pneumatic cavity system can be compressed to different degrees by manually moving the manual operating means, so that the pressure in the closed pneumatic Cavity system prevailing internal pressure, which is supplied to the working valve as a pneumatic control pressure changed. In this case, a continuous variable pressure change can be realized, with the result that the working valve can not be controlled purely digital, but with continuously variable control pressure. A consequence of this is the possibility for sensitive yet precise control of the working valve. Since the control pressure is provided in a closed system, a constant supply of a control pressure medium is unnecessary, which keeps the energy consumption very low. The system is also very robust against environmental influences, which opens up a variety of possible applications.

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

To realize the invention, the working valve can be both of the electrically controllable type and of the pneumatically controllable type. In a pneumatically controllable design directly provided by the control device pneumatic control pressure can be used as a pneumatic control signal. In this case, the working valve includes a pneumatically adjustable valve member. In an electrically operable work valve, a pressure sensor device is expediently provided, which acts as a converter and on the basis of the detected by it pneumatic control pressure causes an electrical control signal, which is used to actuate a valve member of the working valve. Such a working valve contains in particular an electromagnetic drive for adjusting the valve member.

Expediently, the control device contains two components, each referred to as a control component, which are movable relative to one another by carrying out a relative movement designated as a control movement and which together define the volume-variable control chamber of the closed pneumatic cavity system. One of the control components forms the manual actuating means and can be moved manually relative to the other control component to control the volume of the control chamber and, consequently, the therein prevailing, used as a pneumatic control pressure internal pressure to vary. The existing stepless adjustability of the manual actuating means ensures a constant change in the control pressure, if necessary, to the correspondingly variable control of the associated working valve.

To be particularly advantageous, a structure of the control device has proven in the manner of a pneumatic cylinder. In this connection, one of the two control components is formed by a housing and the other control component by a unit containing a piston and a piston rod, which is referred to as a piston-piston rod assembly. As with a pneumatic cylinder, the piston is located within the housing and defines together with the housing at least one housing chamber used as a control chamber. The piston rod projects out of the housing and, like the housing, offers the possibility of a force introduction in order to change the relative position between the housing and piston-piston assembly, whereby the volume of the control chamber and thus the control pressure prevailing therein are changed. During operation of the working device, the housing is expediently used as a manual actuating means, which can be detected, for example, with one hand in order to initiate a manual actuating force that causes the control movement. On the housing but also an additional handle may be attached, which facilitates the manual initiation of the actuating force.

Particularly advantageous is to equip the piston-piston rod assembly with a passing through the housing piston rod, either with an integrally continuous piston rod or with a multi-part piston rod. On opposite sides of the housing protruding end portions of the piston rod can be used to fix the control device to a supporting structure, so that subsequently the control pressure can be influenced by a displacement of the housing in the longitudinal direction of the piston-piston rod assembly can. Such a design is easy to manufacture and ensures a very good linear guide of acting as a manual actuator housing relative to the other control component.

Preferably, the piston is arranged in the housing of the control device such that it axially divides the interior of the housing into two housing chambers, one of which is used as a control chamber for providing the variable pneumatic control pressure. The other housing chamber is expediently constantly vented, in particular by communicating directly with the atmosphere. Depending on the direction in which the relative movement between the two control components takes place, results in a reduction or increase in the volume of the control chamber and, accordingly, an increase or decrease of the pneumatic control pressure, with even a negative pressure can be generated as a pneumatic control pressure.

A particularly comfortable operation of the working device is possible if the control device has spring means by which the two control components are held in a relative position acting as a basic position. This basic position is stabilized by the spring means and can only be canceled by a restoring force of the spring means is overcome. This is done by means of the manually initiated from outside force. If this manual actuation force is removed again, the control components return to the normal position due to the acting spring force. In this way, it is ensured that the control device always provides a reproducible constant pneumatic control pressure in manually unactuated state.

In conjunction with a constructed in the manner of a pneumatic cylinder control device, it is advantageous if a spring unit of the spring means is arranged in each of the two partitioned from the piston in the housing housing chambers, which is effective between the piston and the housing. The spring means ensure a "centering" between the Both control components and also for a kind of mechanical feedback to the operator, which is confronted with increasing displacement of the manual operating means with a stronger counteracting spring force, so that it is given a sense of a more or less adjusted pneumatic control pressure.

The fact that the pneumatic control pressure is provided in a closed cavity system, wherein it is varied only by the volume change of the cavity system, also offers the advantage that on the control side no valves are required, which is another factor for the reduction of manufacturing costs.

In a particularly advantageous embodiment of the working device, the working valve is formed by a pressure regulating valve. The pressure regulating valve has a primary port connectable to a pressure source providing a driving fluid, and also a relief port communicating with a pressure sink, the pressure sink being directly the atmosphere in a pneumatic driving fluid. The pressure control valve also has a secondary connection to which, during operation of the working device, there is a secondary pressure of the drive fluid, the height of which depends on the pneumatic control pressure applied simultaneously to the pressure regulating valve. Depending on the setting, an output or a return flow of drive fluid may be caused to cause the volume of the drive chamber and related functions.

The invention can be used particularly advantageously in connection with an embodiment of the working device as a handling device, which is suitable for raising and / or lowering objects or to hold them in a desired height position in a stable manner. Such a handling device contains a drive device with two drive components which are movable relative to one another under the execution of a working movement and together define a drive chamber which is connected to the secondary connection of the pressure control valve. A first of the two Drive components is connected or connectable to an article holding means to which a repositioned object is at least temporarily fixable. By changing the pneumatic control pressure, supply or discharge of the driving fluid into or out of the driving chamber can be caused to cause a working movement of the first driving component to change the height position of the article holding means. By appropriate specification of the control pressure, the article holding means can be kept stable if necessary in each set height position.

Due to the possibility of constantly variable volume change of the control chamber can be influenced on the flow rate of the drive fluid, which can affect the speed of the working movement. This opens up to the operator a sensitive movement and also positioning of the article holding means or an object fixed thereto.

Particularly useful in connection with a handling device is considered when the non-acting as a manual actuating control component is stationary with respect to the operating movement in the execution exporting first drive component is arranged. In this way, the control device moves together with the first drive component, which makes the handling of the working device particularly simple.

The working device can be used in many ways, even for purposes not previously described. It is conceivable, for example, a use as a door opener in trains that have a pneumatic door operating system. Furthermore, in potentially explosive rooms or cabins it is dangerous or even forbidden to work with electrical signals. Here you could generate harmless pneumatic signals using the working device. By way of example, the handling of parts or the opening of the cabin doors of paint shops may be mentioned here.

When the control device is switched directly to a pressure-regulating, designed as a slide valve working valve, there is also the Possibility to switch or control higher pressures. In this context, one could realize a speed regulation in machine tools with pneumatic motors.

Also worth mentioning is the combination of two control devices with a working as an AND valve working valve to realize a pneumatic two-handed operation. A use for this is in particular that of a press control, in which there is a high security requirement.

The control device could also be designed so that an increase of the control pressure can be brought about by repeated actuation of the control device in the manner of a pumping function. This particular in cases where particularly high pressure changes are desired by the control pressure.

Finally, as a further possible use, a coupling of the control device is addressed with a 5/3-way valve, wherein by means of the control device an optional venting or venting of the directional control valve could be caused.

The invention will be explained in more detail with reference to the accompanying drawings. In its only figure ( FIG. 1 ) schematically illustrates an advantageous embodiment of the working device, in connection with a configuration as a device for repositioning objects suitable handling device.

In the drawing, a working device 1 is illustrated, which is designed in an advantageous manner as a handling device 1a. With such a handling device 1a, any objects, one of which is illustrated in FIG. 2, can be moved and, if necessary, also repositioned. Specifically, the handling device 1 a also allows at least one indicated by a double arrow lifting movement 3 of the article 2 for raising and / or lowering the article 2, which is relevant, for example, in the logistics sector, where objects 2 received at a first location and deposited at a spaced point again should be.

In particular, in connection with a configuration as a handling device 1a, it is advantageous if the working device 1 can not only cause the described vertical lifting movement 3 of the object 2, but also a relative thereto or superimposed transverse movement in particular a horizontal direction, such a movement as a movement is designated and illustrated in the drawing at 4 with a double arrow. Even a superimposed rotary motion or pivoting movement can be realized. By means of these combined movement possibilities, an object 2 can be displaced very variably in space and repositioned as required.

The working device 1 expediently has a support structure 5, which is indicated only schematically, which is formed, for example, by a device frame and which, depending on the construction of the working device 1, can be stationary or movable. The support structure 5 may for example also be a movable extension arm.

From the drawing, a suitably a part of the working device 1 forming fluid-operated drive device 6 is still visible. The drive device 6 has two under the execution of an indicated by a double arrow working movement 7 relatively movable drive components, which are hereinafter referred to as the first drive component 8 and as a second drive component 9. The working movement 7 is preferably a linear movement.

The two drive components 8, 9 together define a drive chamber 12. Due to the relative mobility between the two drive components 8, 9, the drive chamber 12 has a variable volume. The working movement 7 can be brought about by supplying a pressurized drive fluid either into the drive chamber 12 or out of the drive chamber 12.

The drive device 6 is preferably a linear drive device. This should be followed by the further description. In a non-illustrated embodiment, the drive device 6 as Rotary drive device designed.

The second drive component 9 is arranged rigidly or movably on the support structure 5. In the working movement 7, the first drive component 8 moves relative to the second drive component 9, with the result that an item holding means 13 connected to the first drive component 8 carries out a vertical lifting movement 14, with the result that a held on the item holding means 13 Object 2 is caused to the lifting movement 3 described above.

The article holding means 13 is for example a vacuum gripper, a magnetic gripper or a purely mechanical gripper, for example in the manner of a parallel gripper. Regardless of its concrete embodiment, the article holding means 13 is in particular able to releasably hold an object 2, so that the object 2 can be temporarily held for the purpose of its transport and subsequently also deposited again.

The article holding means 13 is preferably arranged detachably on the first drive component 8. In this case, as shown, a direct attachment may be provided or also an indirect connection using a not further illustrated intermediate structure.

By the weight force of the article holding means 13 and the article 2 fixed to the article holding means 13, the first driving component 8 undergoes an operating force "FB" which seeks to move the first driving component 8 in order to reduce the volume of the driving chamber 12.

The first drive component 8 is, in particular, a drive unit 15 which has a drive piston 15a and a drive rod 15b fixedly connected to the drive piston 15a. The second drive component 9 consists in particular of a drive housing 16, in which the drive piston 15a is received linearly movable and from which the drive rod 15b protrudes linearly displaceable. The drive piston 15a, together with an end-side end wall 16a of the drive housing 16, already delimits it mentioned drive chamber 12th

By way of example, the drive rod 15b, starting from the drive piston 15a, extends in a straight line or obliquely downward. The operating force "FB" therefore pulls down the drive unit 15, wherein the drive piston 15a, which acts as a movable wall of the drive chamber 12, is acted upon in the direction of the end-side end wall 16a arranged below it. The currently existing between the drive piston 15a and the end-side end wall 16a axial distance depends on the current filling volume of the drive chamber 12 with drive fluid.

It can be seen that a change in the filling volume of the drive chamber 12 causes a lifting movement 14, 3 in the sense of raising or lowering.

A in the drive housing 16 on the drive chamber 12 axially opposite side of the drive piston 15a lying further chamber 12a of the drive housing 16 has expediently a permanent connection to the atmosphere, so that in their ambient pressure prevails and during the lifting movement 14 an exchange of air with the atmosphere, i. a "breathing" is possible.

In one embodiment, not shown, the drive device 6 is integrated into a kinematic system such that the two chambers 12, 12a are reversed in terms of their function.

For controlled actuation of the drive chamber 12 with a drive fluid, the working device 1 is equipped with an actuating device 17 composed of a plurality of functional components. The main components of the actuating device 17 are a working valve 18 and a control device 19 serving to actuate the working valve 18.

The working valve 18 is preferably a pressure regulating valve 22. A pressure regulating valve 22 permits operation of the handling device 1a in such a manner that the article 2 is balanced at any set height position so that it maintains the relevant height position as long as desired. in the In connection with this functionality, the handling device 1a can also be referred to as a balancer.

The pressure regulating valve 22 is expediently a mechanical or servo-pneumatic pressure regulating valve.

If the balancing functionality is not desired or if the working device 1 is of a different type than a handling device 1a, the working valve 18 can also be of a different type of valve, in particular also of the type of a non-regulating proportional valve.

The further explanation of the embodiment should be based on a designed as a pressure control valve 22 working valve 18.

The pressure regulating valve 22 has a primary connection 23, which is connected in operation of the working device 1 to a pressure source 24 supplying the drive fluid 6 required for actuating the drive device 6. The pressure source 24 provides the drive fluid so that it is under an overpressure, which is referred to as the primary pressure.

The pressure control valve 22 is also provided with a discharge port 25 which is constantly connected to a pressure sink 26. This pressure sink 26 is in particular the atmosphere.

It should be mentioned at this point that the drive fluid is preferably compressed air. In this case, a pneumatic actuation of the drive device 6 takes place. A realization as a hydraulic drive device 6 with a liquid drive fluid is, however, also readily possible.

The pressure regulating valve 22 also has a secondary connection 27, which is connected to the drive chamber 12 during operation of the working device 1. A realized example by means of a fluid line working channel 28 connects the secondary terminal 27 with a connection opening 32 of the drive housing 16, which is in fluid communication with the drive chamber 12.

The pressure control valve 22 has a valve housing 33 and a valve member 34 movably arranged in the valve member 34. As part of a control movement, the valve member 34 is variably positionable within the valve housing 33 to the secondary terminal 27th connect either to the primary port 23 or to the discharge port 25, wherein the respective fluid connection is preferably each with a variable flow cross-section feasible, or shut off. In this way, a fluid flow with different flow rates is possible depending on the current control position of the valve member 34.

The pressure control valve 22 is capable of providing a regulated secondary pressure at the secondary port 27. This secondary pressure is at most as high as the primary pressure, but usually lower.

The height of the regulated, prevailing at the secondary terminal 27 secondary pressure can be predetermined by means of a control signal with which the pressure control valve 22 is driven. Finally, the control signal determines the level of the secondary pressure at which the pressure regulating valve 22 separates the secondary connection 27 from both the primary connection 23 and the discharge connection 25.

Depending on the type of working valve 18 or pressure regulating valve 22, the control signal may be an electrical control signal or a pneumatic control signal. Preferably, the working valve 18 or pressure control valve 22 is of the electrically controllable type, in which the control processes take place on the basis of an electrical control signal. This applies to the embodiment.

Regardless of the type of working valve 18 or pressure regulating valve 22, however, the control signal is based on a pneumatic pressure, which is referred to as control pressure. This pneumatic control pressure is supplied to the pressure regulating valve 22 by means of a control channel 35, for example defined by a control line, which is connected to a pneumatic control input 36 of the pressure regulating valve 22. A pressure sensor device 39 of the actuating device 17, which is preferably designed as a direct component of the pressure control valve 22, acts as a pneumatic-electrical converter and generates from the pneumatic control pressure, the electrical actuating signal for the electric actuatable pressure control valve 22.

When the pressure control valve 22 is of the pneumatically controllable type, the pneumatic control pressure is used directly as a pneumatic control signal for the control operation of the valve member 34.

An advantage in the generation of the pneumatic control pressure is seen in the fact that the pneumatic control pressure medium used for this purpose, ie in particular compressed air, is not constantly fed from the outside, but in one closed internal pneumatic cavity system 37 is provided, wherein the amount of the control pressure medium always remains constant. To change the pneumatic control pressure ultimately only the volume of the cavity system 37, in which the pneumatic control pressure medium is locked, changed.

The aforementioned, closed pneumatic cavity system 37, which is also referred to as "cavity system" below for simplicity, has a volume-variable control chamber 38 formed in the control device 19. The pneumatic control pressure can be tapped at a fluid connection with the control chamber 38 Control output 42. This control output 42 is in fluid communication with the control input 36 of the working valve 18 and pressure control valve 22.

If the pressure control valve 22 is combined with the control device 19 to form a structural unit, the control output 42 and the control input 36 can be directly connected to one another. In the embodiment, the fluid connection is made by the already mentioned control channel 35 which is connected on the one hand to the control output 42 and on the other hand to the control input 36. In this case, the volume contained in the control channel 35 also belongs to the cavity system 37.

The control device 19 has a in the context of a through a Double arrow indicated control movement 43 manually movable manual actuating means 44, wherein the control movement 43 of the manual actuating means 44 causes a change in volume of the control chamber 38. Depending on whether the control movement 43 results in a reduction or enlargement of the control chamber 38, there is an increase or a reduction of the internal pressure prevailing in the cavity system 37 and used as a pneumatic control pressure. Consequently, the pneumatic control pressure without any fluid exchange can be caused solely by a change in volume of the cavity system 37 and in particular the control chamber 38. The trigger is a manual actuating force, which is manually initiated by an operator in the manual actuating means 44.

The prevailing in the cavity system 37 pneumatic control pressure is proportional to the control movement 43. Thus, the control pressure is continuously variable. Thus, the pressure regulating valve 22 a continuously variable control signal can be imposed, which provides the advantageous possibility not only to effect a change in the secondary connection pending secondary pressure, but also to influence the flow rate of the pressure fluid control valve 22 and the drive means 6 overflowing drive fluid, which ultimately a Influencing the movement speed of the lifting movement 3 or 14 allowed. Thus, not only the height position of the article holding means 13 or the object 2 held thereon can be varied, but also the stroke speed associated with the change of the height position.

In order to position the drive unit 15 carrying an object 2 stationarily in any height position, a lifting force is required in the drive chamber 12 of a certain working pressure which, in conjunction with a pressurizing surface of the drive unit 15 delimiting the drive chamber 12-exemplarily formed on the drive piston 15a showing the weight of the drive unit 15 and the operating force "FB" compensated. If the drive unit 15 carrying an object 2 is to be raised, an increase in pressure in the drive chamber 12 is required, which is caused by means of an increase in pressure of the secondary pressure applied to the secondary connection 27. The desired increase in the secondary pressure is achieved by a temporary increase in pressure of the pneumatic control pressure by the manual actuating means 44 according to the dash-dotted line illustration according to arrow 45 is manually displaced in the sense of a reduction in volume of the control chamber 38. Once the desired height position of the drive unit 15 has been reached, the manual operating means 44 is moved back into the basic position existing before the lifting movement is triggered, in which the moved mass is again balanced in terms of its strength.

In a corresponding manner, a lowering of the drive unit 15 can be caused by the manual actuating means 44 is displaced from the force balance on the drive means 16 causing basic position opposite to the direction of the arrow 45a, so that the volume of the cavity system 37 increases and the pneumatic control pressure is lower , In such a case, in the pressure control valve 22, a fluid connection between the secondary port 27 and the discharge port 25, which allows escape of drive fluid from the drive chamber 12, to allow the drive unit 15, the desired drop. Again, the sinking speed can be stopped at any time and at any point by the manual operating means 44 is moved back into the basic position defining the equilibrium state.

When filling the cavity system 37 with the control pressure medium and / or by a corresponding adjustment of the basic position of the manual operating means 44, the system can be easily adjusted with respect to each weight to be handled, so that a constant height position is maintained when the manual operation means 44 assumes the normal position. You can without further provide means that allow a so-called teaching of various loads.

At this point, it should be mentioned that the control device 19 is coupled in a preferred development of a security system, which causes a movement is only possible if the manual operating means 44 is moved by an operator.

It is also possible to use the control device 19 as a feedback means by a safety system in the event of a fault or other event, a pneumatic reaction to the manual actuating means 44 triggers, which is registered by a person holding the manual actuator 44.

The designed for a manual operation control device 19 advantageously includes two under execution of the control movement 43 relative to each other movable first and second control components 45, 46. The first control component 45 forms advantageously the manual actuating means 44, which is movable relative to the second control component 46 in the context of the control movement , Both control components 45, 46 together limit the above-mentioned control chamber 38. It is considered to be particularly advantageous to carry out the control device 19 in the manner of a pneumatic cylinder, as is the case in the illustrated advantageous embodiment. Such a structure is characterized in particular by the fact that the first control component 45 forming the manual actuating means 44 is designed as a housing 47 and the second control component 46 as a piston-piston rod assembly 48.

The housing 47, which is virtually a cylinder housing, has an elongated housing interior 51, in which a piston 48 a of the piston-piston rod assembly 48 is received linearly displaceably under sealing. A piston rod 48b fixedly connected to this piston 48a projects out of the housing 47 at the front side, its length portion located outside the housing 47 forming a fastening portion 48c which can be used for fixing the control device 19.

It is advantageous if the piston rod 48b completely penetrates the housing 47 and, as in the exemplary embodiment, protrudes on opposite sides of the housing 47, each with a fastening section 48c. By means of the two fastening portions 48c, the piston-piston rod assembly 48 is fastened to a holder 52.

The housing interior 51 is axially divided by the piston 48 a into a first housing chamber 53 and a second housing chamber 54. In the control movement 43, the length of the two housing chambers 53, 54, which are bounded on the piston 48 a opposite end face in each case by an end-side end wall 47 a, 47 b of the housing 47 changes. To the extent that each extends a housing chamber 53 or 54, the respective other housing chamber 54, 53 shortened.

The passing through the housing 47 piston rod 48b passes under sealing slidable the two end-side end walls 47a, 47b, of which it is expediently guided in each case linearly displaceable.

The one, first housing chamber 53 forms the control chamber 38. The second housing chamber 54 is expediently permanently in communication with the atmosphere, so that it is depressurized and in the control movement 43 an exchange of air with the atmosphere is possible in order not to hinder the control movement 43.

To cause the control movement 43, it is sufficient to use the housing 47 as a manual operation means 44 and to detect with one hand and to move relative to the piston-piston rod assembly 48 linearly in one or the other direction. Depending on the direction of displacement, this results in an increase or decrease in the volume of the first housing chamber 53 forming the control chamber 38.

Due to the housing 47 completely passing through the piston rod 48b is the manual actuating means 44, which is formed by the housing 47, transverse to the direction of the control movement 43 optimally supported, so that a low-wear operation of the control device 19 is possible.

In an embodiment not shown, the piston rod 48b designed and arranged so that it protrudes on only one side of the piston 48a and penetrates only one of the end-side end walls 47a or 47b.

The two attachment portions 48c may be end portions of a one-piece piston rod or also the end portions of two length portions of a multi-piece piston rod which are connected from opposite sides to the piston 48a.

In order to specify the above-mentioned basic position of the manual operating means 44, the control device 19 is expediently equipped with spring means 55 which fix the two control components 45, 46 in an elastically flexible manner in a relative position forming the basic position.

The two control components 45, 46 are mutually resiliently clamped together by the spring means 55 in such a relative basic position that the manual control means 44 forming the first control component 45 is movable from the basic position in opposite directions. Depending on the direction of movement, the volume of the control chamber 38 is reduced or increased.

The expediently existing spring means 55 are arranged and designed so that in each direction of movement of the control movement 43, which starts from the basic position, a restoring spring force is overcome. The spring forces are in the home position of the manual operating means 44 in equilibrium. Consequently, releasing the manual operating means 44 causes an automatic return to the normal position and an almost immediate stop of the working movement 7, because the secondary pressure 27 adjusts in this case immediately back to the working pressure, which fixes the current height position of the drive unit 15.

Expediently, the spring means 55 are composed of two separate spring units 55a, 55b which act in opposite directions on the manual operating means 44 and the first control component 45, respectively. In connection with an embodiment of the control device 19 in the manner of a pneumatic cylinder, it is advantageous to accommodate each of the two spring units 55a, 55b in one of the two housing chambers 53, 54, so that they are each supported between the housing 47 and the piston-piston rod assembly 48. In an embodiment not shown, the spring units 55a, 55b are arranged outside the housing 47.

The spring means not only cause a defined basic position of the control device 19, but also give the operator a feeling for the operation, because the spring force to be overcome is greater, the stronger the manual actuating means 44 is deflected from the basic position.

As a holder 52 for the second control component 46 is especially the first drive component 8, which is connected to the object to be moved 2 or connectable. An advantageous effect of this attachment is that the entire control device 19 is displaced together with the first drive component 8. Thus, in particular, it is also possible to precisely guide the object 2 to be repositioned manually.

In principle, the second control component 46, relative to which the manual control means 44 forming the first control component 45 is movable in the context of the control movement 43, be attached to any other support 52. In this context, dash-dotted lines illustrated at the top left in the drawing, alternatively to use the support structure 5 as a holder 52.

A realization of the control device 19 in the manner of a pneumatic cylinder is a very cost-effective solution because you can fall back on common pneumatic cylinders that require only minor adjustments.

Claims (16)

1. Work device, with an actuating device (17) suitable for actuation of a fluid-actuated drive unit (6), which has an operating valve (18) which may be controlled by a control signal generated on the basis of a pneumatic control pressure and which contains a control device (19) supplying the pneumatic control pressure and which, for its manual actuation, is equipped with movable manual actuation means (44) and has a control outlet (42) providing the pneumatic control pressure, wherein the actuating device (17) has a closed pneumatic hollow space system (37), characterised in that there belongs to the hollow space system (37) a volume-changing control chamber (38) of the control device (19) connected to the control outlet (42), the volume of which is continuously variable with the result of a constantly variable change in control pressure by manual movement of the manual actuation means (44).
2. Work device according to claim 1, characterised in that the operating valve (18) is of the electrically controllable type, wherein the actuating device (17) has, for detecting the pneumatic control pressure and based on the detected pneumatic control pressure, a pressure sensor device (39) generating an electrical control signal serving to control the operating valve (18) and expediently forming a direct constituent of the operating valve (18).
3. Work device according to claim 1, characterised in that the operating valve (18) is of the pneumatically controllable type, wherein a pneumatic control signal for the operating valve (18) is formed directly by the pneumatic control pressure.
4. Work device according to claim 2 or 3, characterised in that the operating valve (18) has a pneumatic control inlet (36), which is pneumatically connected to the control outlet (42) of the control device (19) to receive the control pressure.
5. Work device according to any of claims 1 to 4, characterised in that the control device (19) has two control components (45, 46), movable relative to one another in the execution of a control movement (43), and together bounding the volume-changing control chamber (38), wherein one of the control components (45) forms the manual actuation means (44), by manual actuation of which the control movement (43) changing the volume of the control chamber (38) relative to the other control component (46) may be generated.
6. Work device according to claim 5, characterised in that the control device (19) is designed in the manner of a pneumatic cylinder, wherein its one control component (45) is formed by a housing (47) and its other control component (46) by a piston-piston rod assembly (48), wherein the piston (48a) of the piston-piston rod assembly (48) is mounted in the housing (47) and the piston rod (48b) of the piston-piston rod assembly (48) extends out of the housing (47), and wherein the piston (48a) together with the housing (47) bounds the volume-changing control chamber (38), the volume of which may be varied constantly by a relative movement between the housing (47) and the piston-piston rod assembly (48) which takes place during the control movement (43).
7. Work device according to claim 6, characterised in that the piston-piston rod assembly (48) has a piston rod (48b) passing through the housing (47) and extending out of the housing (47) on opposite sides.
8. Work device according to claim 6 or 7, characterised in that the housing (47) forms the manual actuation means (44), wherein the control movement (43) results from a manually generated linear movement of the housing (47) relative to the piston-piston rod assembly (48).
9. Work device according to any of claims 5 to 8, characterised in that inside the housing (47) the piston (48a) divides two housing chambers (53, 54) axially from one another, with one housing chamber (53) forming the control chamber (38) while the other housing chamber (54) is expediently constantly vented.
10. Work device according to any of claims 5 to 9, characterised in that the control device (19) has spring means (55) by which the two control components (45, 46) are held relative to one another in a basic position, starting from which the control component (45) with the manual actuation means (44) may be moved to execute the control movement (43) while overcoming a resetting spring force of the spring means (55), alternately in one of two opposite directions relative to the other control component (46), wherein the volume of the control chamber (38) undergoes an increase or a decrease depending on the direction of movement.
11. Work device according to claim 10 in conjunction with claim 9, characterised in that, in each of the two housing chambers (53, 54), there is located one of two spring units (55a, 55b) of the spring means (55) which are effective between the piston (48a) and the housing (47).
12. Work device according to any of claims 1 to 11, characterised in that the operating valve (18) controllable by the control device (19) is a pressure-control valve (22) which has a primary port (23) which may be connected to a pressure source (24) providing driving fluid, a relief port (25) communicating with a pressure sink (26), and a secondary port (27) which may be connected to a volume-changing drive chamber (12) of the drive unit (6), wherein expediently the level of secondary pressure at the secondary port (27) of the pressure-control valve (22) and/or the flow rate of the driving fluid flowing into or out of the drive chamber (12) may be constantly and variably preset by the pneumatic control pressure.
13. Work device according to any of claims 1 to 12, characterised in that it has a drive unit (6) connected to the operating valve (18) and actuable by fluidic power from the actuating device (17).
14. Work device according to claim 13 in conjunction with claim 12, characterised in that the drive unit (6) contains a volume-changing drive chamber (12) which is connected to the secondary port (27) of the pressure-control valve (22).
15. Work device according to claim 14, characterised in that it is in the form of a handling device (1a) suitable for the raising or lowering of objects (2), wherein the drive unit (6) has two drive components (8, 9) which together bound the volume-changing drive chamber (12), of which the one first drive component (8) may be moved relative to the other second drive component (9), with simultaneous changing of the volume of the drive chamber (12) and executing an operating movement (7), wherein the movable first drive component (8) is or may be connected to object holding means (13) for holding an object (2), the height of which in space may be varied by the operating movement (7).
16. Work device according to claim 15 in conjunction with any of claims 5 to 11, characterised in that the control component (46) not forming the manual actuation means (44) is mounted immovably relative to the first drive component (8), so that it accompanies the operating movement (7) of the latter.

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