EP2921261B2 - Pneumatically operable working machine - Google Patents

Description

The invention relates to a pneumatically operable working device for use in body construction in the motor vehicle industry, with a cylinder which has a cylinder housing, a piston displaceable therein and a piston rod connected to it, linearly displaceable and led out of the cylinder housing, and with a cylinder connected to the cylinder housing Head housing, wherein an area of the piston rod projecting into the head housing interacts with at least one toggle lever for pivoting an arm assigned to the toggle lever, in particular gripping arm or tensioning arm, this arm being mounted in the head housing and being pivotable between a closed position and an open position.

Such a tool is from the DE 296 15 157 U1 known. In this case, two toggle levers pivot directly on the end of the piston rod located in the head housing. Here, two gripping arms can be pivoted between a closed position and an open position. In the closed position, the gripping arms are arranged parallel to one another. A bearing axis for the two toggle levers which is arranged in the region of the free end of the piston rod is provided at the end with bearing rollers which are guided in guide grooves in the head housing.

Due to the direct connection of the toggle levers to the piston rod, the opening angle of the gripper arms cannot be adjusted. In addition, this design does not allow a particularly large opening angle of the gripping arms to be represented, because the piston rod projects into the path of movement of the central joint of the toggle lever.

In addition, in this implement the free end of the piston rod is guided over the axis passing through it, which at the same time forms the bearing axis of the toggle levers. The length of the piston rod cannot be adjusted on this implement. This means that the opening angle of the arms cannot be adjusted.

Pneumatically operated tools that have gripping or clamping arms, and in which a piston rod that cannot be adjusted in length are used, are also from the DE 10 2004 040 606 B3 . EP 2 241 402 A1 and US RE 41,223 E known.

In the EP 2 548 700 A1 describes a pneumatically operable working device in which a piston of a cylinder is positioned in the open position of a tensioning arm in the region of a base of the cylinder housing. In order to be able to set the opening angle of the tension arm, the piston rod is designed to be variable in length and has piston rod parts with threaded sections, the piston rod parts being screwed into one another. By rotating the piston rod part facing the bottom of the cylinder housing, in the case of pistons arranged in the region of the bottom, the length of the piston rod can be changed by means of turning the piston rod part that are accessible from the outside, and thus the opening angle of the tensioning arm can be continuously adjusted.

A pneumatically operable implement that has the features of the upper portion of claim 1 is known from the US 4,576,367 A. known. In this pneumatically operated implement, the bearing element has a single receptacle for the pivotable mounting of a single joint connector. This interacts with a toggle lever to which an arm is assigned which is mounted in the head housing. This arm is a clamping arm for clamping a workpiece.

The object of the present invention is to develop a working tool of the type mentioned at the outset such that a large pivoting angle range, in particular a large opening angle of the arm, can be represented with a universal design of the connection of the piston rod and at least one arrangement of the toggle lever and the associated arm.

The object is achieved by a pneumatically operable implement, which is designed according to the features of claim 1.

In the pneumatically operable implement according to the invention, the piston rod receives a bearing element for the toggle lever in the region of its end projecting into the head housing. The bearing element is guided in a guide of the head housing in the direction of the longitudinal axis of the piston rod. The bearing element has a receptacle for the pivotable mounting of an articulated connector at a radial distance from the longitudinal axis of the piston rod. This is pivotally connected to the arm at a distance from a pivot axis of the arm in the region of an end facing away from the bearing element. The end pivot axes of the joint connector and the pivot axis of the arm are arranged parallel to each other.

In the working device according to the invention, the at least one toggle lever for pivoting the arm assigned to the toggle lever, in particular the gripping arm or clamping arm, is not mounted directly in the piston rod, but instead the bearing element is provided for mounting this toggle lever. This bearing element is designed so that the toggle lever engages the bearing element at a radial distance from the longitudinal axis of the piston rod. Because of this mounting, the piston rod does not limit the pivoting path of the articulated connector forming part of the toggle lever.

In the working device according to the invention, the bearing element is designed in such a way that it has receptacles on opposite sides for the pivotable mounting of two joint connectors. Depending on the design of the working device, a receptacle can remain free with this design, with which only one of the two receptacles receives an articulated connector to which an arm is assigned, or both receptacles are equipped with articulated connectors so that the working device has two arms. Because the bearing element is guided in a guide of the head housing in the direction of the longitudinal axis of the piston rod, forces can be optimally introduced into the arm or from the arm into the bearing element, regardless of whether the implement has one or two arms.

The implement can thus be designed such that the receptacles for the pivotable mounting of the two joint connectors are provided on the respective side of the bearing element, thus laterally with respect to the longitudinal axis of the piston rod. This design enables a structurally simple connection of the two articulated connectors that interact with the arms.

If only one arm is present in the implement, the same bearing element can be used for reasons of standardization of the implement, in which case only one joint connector is connected to the bearing element for connection to one arm, while the other receptacle of the bearing element does not accept a joint connector.

If the bearing element receives the two hinge connectors, it is considered to be particularly advantageous if the bearing element, the hinge connectors and the arms are arranged symmetrically to a plane running through the longitudinal axis of the piston rod. This results in a symmetrical design of the implement in the area of the head housing and the two arms, so that gripping or clamping forces introduced into the two arms are introduced symmetrically into the implement when contacting a component associated with the implement, for example a body panel.

The guidance of the bearing element in the guidance of the head housing in the direction of the longitudinal axis of the piston rod is particularly advantageous. This guidance is important not only from the point of the actual guidance of the bearing element in the head housing, but also from the aspect of introducing the forces acting on the arm or arms from the bearing element into the head housing. This guided mounting of the bearing element makes it possible to implement the implement both in the variant with one arm and in the variant with two arms. In the variant with one arm, forces are introduced asymmetrically into the head housing via the arm. This is easily possible due to the guidance of the bearing element in the head housing, because the forces are introduced directly into the head housing via the bearing element and the guide assigned to it.

From a structural point of view and from the point of view of wear, it is considered to be particularly advantageous if the bearing element is mounted in a guide of the head housing by means of a sliding and / or roller bearing. In the case of roller bearings in particular, the use of roller bearings in the form of roller or barrel bearings is considered to be advantageous.

The guide has in particular mutually parallel guide surfaces which are arranged parallel to the pivot axis of the arm.

According to a structurally particularly preferred design, it is provided that the respective receptacle has a plate-shaped attachment which is connected to a base body of the bearing element, the attachment having a hole for receiving a bearing pin for the associated joint connector. Such a design enables a simple connection of the joint connector to the bearing element, with a structurally simple design of this arrangement.

A particularly good guidance of the bearing element with an optimal force application point of the joint connector or joints results in the working device according to the invention in that the bearing element in the axial direction of the piston rod has one behind the other bearing parts for supporting the bearing element in the head housing, whereby, based on the axial direction of the Piston rod, the at least one receptacle is arranged between the bearing parts. Because of this design, forces can be transmitted between the bearing element and the articulated connector with a high tilting stability of the bearing element.

The pneumatically operated implement has in particular a toggle lever for pivoting an arm assigned to it, or in particular two toggle levers, each of the two toggle levers serving to pivot an arm assigned to this toggle lever. The arm is in particular a gripping arm.

The toggle lever or the toggle lever are arranged in the closed position of the arm or the arms in particular in an over-dead center position. A further pivoting of the respective toggle lever beyond the dead center position is prevented by a stop which can be arranged as desired and which has the task of preventing an axial displacement of the piston rod or components interacting with this piston rod in the direction of a bottom of the cylinder housing.

According to a preferred development of the invention, it is provided that the piston rod of the implement cannot be changed in length and the open position of the arm can be adjusted continuously. In this case, the piston rod preferably has a threaded section and, in the region of the threaded section, receives a stop part which is adjustable in the longitudinal direction of the piston rod and which, in the open position of this arm, bears against a system which is stationary with respect to the head housing, the piston rod being rotatable with respect to its longitudinal axis and moreover is rotatable with respect to the bearing element.

Due to this design of the implement, the position of the stop part with respect to the piston rod, based on the axial direction of the piston rod, can be changed, so that the opening angle of the arm can be adjusted continuously by adjusting the stop part. At this opening angle, the stop part contacts the stationary part with respect to the head housing Investment.

The working device can be designed such that the cylinder and the head housing represent separate structural units or a common structural unit.

The stop part is in particular non-rotatably positioned in the head housing. If the piston rod is rotated with respect to its longitudinal axis, and thus the position of the stop part changes in the direction of the longitudinal axis of the piston rod, the stop part is accordingly not rotated and is only displaced in the axial direction of the piston rod. This positioning of the stop part in the head housing can be achieved in different ways, for example by guiding the stop part in the direction of the longitudinal axis of the piston rod in the head housing, or by an out-of-round design of the stop part, the non-round outer contour of the stop part with a correspondingly designed inner contour of the head housing cooperates.

The system, which is stationary with respect to the head housing, can be designed in different ways. The stationary system has the task of forming the bearing surface for the stop part, which prevents further axial adjustment of the stop part when the stop part contacts the stationary system and thus defines the open position of the arm. In particular, it is provided that the contact surface extends orthogonally to the longitudinal axis of the piston rod. Here, a contact surface of the stop part that extends orthogonally to the longitudinal axis of the piston rod interacts with the stop surface when the stop part rests.

In order to ensure that there is no adjustment of the stop part and piston rod during operation of the implement, and thus no adjustment of the open position of the arm, it is provided that the thread between the piston rod and the connection part is self-locking.

The position of the stop part can be adjusted in a structurally particularly simple manner if a bottom of the cylinder housing facing away from the head housing has means for rotating the piston rod in the closed position of the arm when the piston is arranged in the region of the bottom. These means penetrate in particular the floor and can preferably be displaced in the direction of the longitudinal axis of the piston rod in order to be brought into engagement with the piston rod. It is then possible to turn the piston rod from outside the cylinder housing. If the stop part is in the desired set position, the means are brought out of engagement with the piston rod again. This takes place, for example, when the cylinder is pressurized by the pressure medium.

It is also considered advantageous if a bottom of the cylinder housing facing away from the head housing has means for axially displacing the piston rod in the closed position of the arm when the piston is arranged in the region of the bottom in order to move the toggle lever out of an over-center position. This means for axially displacing the piston rod in the closed position of the arm is provided in order to enable the arm to be released from the over-dead center position of the toggle lever in a fluid-independent manner if the supply of fluid to the cylinder should fail in the closed position of the arm. To achieve this, it is only necessary to exert a force on the piston rod via the means for axially displacing the piston rod, with which the piston rod is moved slightly axially and the toggle lever is pivoted out of the dead center position. As a rule, the pivoting angle of the toggle lever from the dead center position to the overdead position is a fraction of an angular degree, so that it is only necessary to move the toggle lever out of the overdead position by moving the piston rod a short distance by means of the means for axially displacing the piston rod, which corresponds to this small angle.

It is considered to be particularly advantageous if the means for axially displacing the piston rod have the means for rotating the piston rod. The means are designed in the simplest manner as displaceable in the bottom of the cylinder housing and a plunger sealed against the bottom, which has a receptacle for a tool for rotating the plunger outside the cylinder housing and a receptacle for non-rotatably engaging in a receptacle of the latter within the cylinder housing facing end of the piston rod. When the plunger is inserted into the piston rod, the piston rod can be moved axially by applying an impact force to the plunger, and the toggle lever can thus be moved out of the dead center position. Irrespective of this, the plunger has the task of turning the piston rod about its longitudinal axis when the plunger is rotated by means of the tool and thus adjust the stop part with respect to the piston rod.

Further features of the invention are shown in the subclaims, the description of the figures and the figures themselves, it being noted that all individual features and all combinations of individual features are essential to the invention.

Fig. 1

ein erstes Ausführungsbeispiel eines pneumatisch betreibbaren Arbeitsgerätes, das einen einzigen Arm aufweist, veranschaulicht in einer Schnittdarstellung bei einer eingestellten geöffneten Stellung von 30°,

Fig. 2

das Arbeitsgerät gemäß Fig. 1 in einer geöffneten Zwischenstellung,

Fig. 3

das Arbeitsgerät gemäß der Fig. 1 und 2 in der geschlossenen Stellung,

Fig. 4

das erste Ausführungsbeispiel des Arbeitsgerätes in einem Schnitt durch eine Kolbenstangenachse des Arbeitsgeräts, senkrecht zur Schnittdarstellung gemäß der Fig. 1 bis 3 geschnitten, veranschaulicht für eine veränderte eingestellte geöffnete Stellung,

Fig. 5

das erste Ausführungsbeispiel des Arbeitsgerätes, veranschaulicht bei einer eingestellten geöffneten Stellung von 50°,

Fig. 6

das Arbeitsgerät gemäß Fig. 5 in einer geöffneten Zwischenstellung,

Fig. 7

das Arbeitsgerät gemäß der Fig. 5 und 6 in der geschlossenen Stellung,

Fig. 8

ein zweites Ausführungsbeispiel eines pneumatisch betreibbaren Arbeitsgerätes, das zwei Arme aufweist, veranschaulicht in einer Schnittdarstellung bei einer eingestellten geöffneten Stellung von 90°,

Fig. 9

das Arbeitsgerät gemäß Fig. 8 in einer geöffneten Zwischenstellung,

Fig. 10

das Arbeitsgerät gemäß der Fig. 8 und 9 in der geschlossenen Stellung,

Fig. 11

das zweite Ausführungsbeispiel des Arbeitsgerätes, veranschaulicht bei einer eingestellten geöffneten Stellung von 160°,

Fig. 12

das Arbeitsgerät gemäß Fig. 11 in einer geöffneten Zwischenstellung,

Fig. 13

das Arbeitsgerät gemäß der Fig. 11 und 12 in der geschlossenen Stellung,

Fig. 14

eine vergrößerte Schnittdarstellung durch den Bodenbereich des Zylinders bei nicht in Wirkstellung befindlichem Stößel,

Fig. 15

eine Schnittdarstellung gemäß Fig. 14, bei in Wirkstellung befindlichem Stößel,

Fig. 16

eine vergrößerte Schnittdarstellung der Anbindung eines Lagerelements an einen Arm.

The invention is shown in the figures on the basis of two preferred exemplary embodiments, without being limited thereto. It shows:

Fig. 1

a first embodiment of a pneumatically operable implement, which has a single arm, illustrated in a sectional view with a set open position of 30 °,

Fig. 2

the implement according to Fig. 1 in an open intermediate position,

Fig. 3

the implement according to the Fig. 1 and 2 in the closed position,

Fig. 4

the first embodiment of the implement in a section through a piston rod axis of the implement, perpendicular to the sectional view according to the 1 to 3 cut, illustrated for a changed set open position,

Fig. 5

the first embodiment of the implement, illustrated with a set open position of 50 °,

Fig. 6

the implement according to Fig. 5 in an open intermediate position,

Fig. 7

the implement according to the Fig. 5 and 6 in the closed position,

Fig. 8

2 shows a second exemplary embodiment of a pneumatically operable working device, which has two arms, illustrated in a sectional view with a set open position of 90 °,

Fig. 9

the implement according to Fig. 8 in an open intermediate position,

Fig. 10

the implement according to the Fig. 8 and 9 in the closed position,

Fig. 11

the second embodiment of the implement, illustrated with a set open position of 160 °,

Fig. 12

the implement according to Fig. 11 in an open intermediate position,

Fig. 13

the implement according to the Fig. 11 and 12 in the closed position,

Fig. 14

2 shows an enlarged sectional view through the base region of the cylinder with the plunger not in the active position,

Fig. 15

a sectional view according to Fig. 14 , with the plunger in the active position,

Fig. 16

an enlarged sectional view of the connection of a bearing element to an arm.

figure description

The figures show a pneumatically operated implement 1, which is used in particular in the body shop of the motor vehicle industry. The implement 1 is a handling gripper with a single arm 2 - gripping arm - according to the embodiment according to the 1 to 7 - or with two arms 2 - two gripper arms - according to the embodiment of the 7 to 13 educated. Both embodiments have a similar structure. In this respect, the representation of the 1 to 4 described the first embodiment.

As shown in the 1 to 4 the implement 1 has a cylinder 3. A head housing 5 is connected to a cylinder housing 4 via fastening means (not illustrated). The cylinder housing 4 accommodates a piston 6 displaceable in this and a piston rod 7 connected to it, linearly displaceable and guided out of the cylinder housing 4 and sealed, and not variable in length. A region of the piston rod 7 projecting into the head housing 5 interacts with at least one toggle lever 8 for pivoting the arm 2 assigned to it. This arm 2 is mounted in the head housing 5 via an axis 9 and about this axis 9 between an open position ( Fig. 1 ) and a closed position ( Fig. 3 ) swiveling.

The open position of the arm 2 is infinitely adjustable. For this purpose, the piston rod 7 has a threaded section 10 and receives in its area a stop part 11 which is adjustable in the longitudinal direction of the piston rod 7. The stop part 11 is in the open position of the arm 2 on a stationary with respect to the cylinder housing 4, which is designed as an annular contact surface 12 of the head housing 5, which surrounds the piston rod 7 and is arranged orthogonally to the longitudinal axis 13 of the piston rod 7. The cooperating with the contact surface 12 of the head housing 5, also annular contact surface of the stop part 14 is designated by the reference number 14. This contact surface 14 is arranged parallel to the contact surface 12.

The stop part 11 is non-rotatably positioned in the head housing 5, specifically via a groove, not shown, which extends parallel to the longitudinal axis 13 of the piston rod 7 and into which the stop part 11 engages. The thread in the area of the threaded section 10 between the piston rod 7 and the stop part 11 is self-locking.

The piston rod 7 is rotatable with respect to its longitudinal axis 13 and receives a bearing element 15 for the toggle lever 8 in the region of its end facing the toggle lever 8. The piston rod 7 is rotatable about the longitudinal axis 13 with respect to the bearing element 15. For this purpose, the piston rod 7 is inserted into a receptacle 16 of the bearing element 15 and is fixedly connected to the bearing element 15 by means of a form-locking ring 17 extending the longitudinal axis 13.

This connection enables the piston rod 7 to be rotated about the longitudinal axis 13 with respect to the receptacle 16 and thus the bearing element 15.

A bottom 18 of the cylinder housing 4 facing away from the head housing 5 has means 19 for rotating the piston rod 7 in the closed position ( FIG. 3 ) of the arm 2 with the piston 6 arranged in the region of the base 18. This means 19 is a plunger, which is sealed in the bottom 18 and is displaceable in the longitudinal axis 13 of the piston rod 7. The end of the plunger 19 arranged outside the cylinder housing 4 has a hexagon recess 20 for receiving a tool (not shown) for rotating the plunger 19 about the longitudinal axis 13, the tool being inserted into the hexagon recess 20 with a hexagon end. The end arranged inside the cylinder housing 4 is provided with a projection 21 with a hexagonal cross section. These details are the representation of the Fig. 13 can be removed when the plunger 19 is not in engagement. Fig. 14 shows the engagement of the plunger 19, wherein the projection 21 in the closed position of the arm 2 is inserted into a recess 22 of cross-section of the facing end of the piston rod 7. By rotating the plunger 12 by means of the tool, the piston rod 7 can thus be rotated and, as a result, the position of the stop part 11 relative to the piston rod 7 can be changed. Fig. 14 illustrates that with the plunger 19 inserted in its recess 2 in the bottom end position of the piston rod 7, an axial gap 23 remains between a head 24 of the plunger 19 and the base 18, so that when an external force or impact force is applied to the plunger 19 in the region of its head 24 there is an axial displacement of the plunger 19 to a consequent mechanical displacement of the piston rod 7 slightly away from the base 18.

The bearing element 15 is symmetrical with respect to a plane that runs through the longitudinal axis 13 of the piston rod 7. Two axes 25 are mounted in the bearing element 15, the respective axis 25 receiving roller-shaped roller bearing elements 26 on both sides of the bearing element 15, which are guided in a bearing groove 27 extending in the longitudinal axis 13. As a result, the bearing element 15 is guided in the direction of the longitudinal axis 13 essentially without play. On opposite sides, the bearing element 15 has plate-shaped receptacles 28 in the manner of tabs which are connected to a base body 39 of the bearing element 15. Each receptacle 28 is intended to receive a plate-shaped joint connector 29 in the region of an axis 30. In the embodiment which has only one arm 2, only one receptacle 28 is connected, while the other receptacle 28 remains free. This other mount is only connected in the event that a second arm 2 is present.

The bearing element 15 has in the axial direction 13 of the piston rod 7 one behind the other at a distance from each other the roller bearing elements 26 for mounting the bearing element 15 in the head housing 5. Relative to the axial direction 13 of the piston rod 7, the receptacle 28 or the two receptacles 28 is arranged between these roller bearing elements 26.

The joint connector 29 is pivotally connected to the arm 2 in the region of an axis 31 in the region of its end facing away from the bearing element 15. This axis 31 is positioned at a distance from the axis 9 of the arm 2. The axis 9 and the axes 30 and 31 are arranged parallel to one another. The axes 9, 30 and 31 are designed so that the axes 30 and 31 and 9 and 31 form the toggle lever 8, wherein in the open position according to Fig. 1 the connecting line between the axes 30 and 31 makes an angle of less than 90 ° with respect to the connecting line of the axes 9 and 31 with respect to their centers, while in the closed position of the arm according to Fig. 3 This angle is slightly greater than 90 °, so that there is a slight over-center position in which the bearing element 15 is fixed in the direction of the longitudinal axis 15 and in the direction of the piston rod 7 by the roller bearing elements 26 on the piston rod side in the region of the end of the bearing groove 27, which is the Piston rod faces, abut on this end 32 of the bearing groove 27.

Fig. 15 shows a detail of the mounting of the articulated connector 29 in the arm 2. Here, the axis 31 is extended and engages in a guide groove 33 of the head housing 5 which extends essentially over a quarter circle.

• Das Zylindergehäuse 4 ist durch den Kolben 5 in zwei Arbeitsräume 34 und 35 des Fluids unterteilt. Ausgehend von der geöffneten Stellung von 30° des Arms 2 bezüglich der Längsachse 13, in der sich der Arm 2, bezogen auf die eingestellte Position des Anschlagteils 11 in der maximal geöffneten Stellung befindet, wird in bekannter Art und Weise der Arbeitsraum 34 mit Fluid beaufschlagt, sodass der Kolben 6 in Richtung des Bodens 18 bewegt wird. Hierbei gelangt das Anschlagteil 11 im Bereich dessen Anlagefläche 14 außer Kontakt mit der Anlagefläche 12 des Kopfgehäuses 5. Der Kolben 6 und die Kolbenstange 7 ziehen das Lagerelement 15 mit und es wird über den Kniehebel 8 der Arm 2 mit dessen im Bereich des freien Endes des Armes 2 angeordneten Greifelement 36 in Richtung eines im Kopfgehäuse 5 gelagerten Greifelements 37 bewegt. - Die Zwischenstellung ist in Fig. 2 veranschaulicht.

The operation of the implement 1 according to the embodiment of the 1 to 4 is as follows:

• The cylinder housing 4 is divided by the piston 5 into two working spaces 34 and 35 of the fluid. Starting from the open position of 30 ° of the arm 2 with respect to the longitudinal axis 13, in which the arm 2 is in the maximum open position with respect to the set position of the stop part 11, the working space 34 is acted upon with fluid in a known manner , so that the piston 6 is moved in the direction of the bottom 18. Here, the stop part 11 arrives in the area of its contact surface 14 out of contact with the contact surface 12 of the head housing 5. The piston 6 and the piston rod 7 pull the bearing element 15 with it and the arm 2 with its in the area of the free end of the Arm 2 arranged gripping element 36 moves in the direction of a gripping element 37 mounted in the head housing 5. - The intermediate position is in Fig. 2 illustrated.

When the piston 6 moves further, it finally reaches its end position adjacent to the base 18, in which the two gripping elements 36 and 37 make contact or a sheet metal arranged between them is gripped by means of the gripping elements 36 and 37. When the arm 2 is closed, the toggle lever 8 is in a slight dead center position, in which the connecting line of the two axes 30 and 31, based on their center point, is at an angle slightly unequal to 90 ° to the longitudinal axis 13 of the piston rod 7 is arranged such that the center point of the axis 30 is arranged somewhat closer to the ground than the center point of the axis 31. Since in this closed position of the arm 2 a stop position is likewise formed in which the roller bearing elements 26 on the piston rod side at the end 32 of the guide groove 33, the toggle lever 8 can only be moved out of this over-center position by actively loading the other working space 35 into the fully open position according to FIG Fig. 1 when the stop part 11 is in contact with the head housing.

If the supply of the fluid to the working device 1, in particular to the working space 35, has failed, this over-center position of the toggle lever 8 can be released by the mechanical action of the plunger 19 described above. The axial displacement of the piston rod 7 and thus the corresponding axial displacement of the bearing element 15 mean that the joint connector 29 is pivoted slightly so that the center point of the axis 30 is further away from the ground than the center point of the axis 31. In this position there is a pivoting movement of the arm 2 mechanically possible by gripping the arm 2.

As before, regarding the representation in particular of the Fig. 13 and 14 illustrates, the position of the stop member 11 can be changed by rotating the piston rod 7. The plunger 19 is inserted into the recess 22 of the piston rod 7. The plunger 19 is moved back when the cylinder 3 is pressurized to transfer the piston 6 from the closed position of the working device, with pressure medium being fed to the working space 35 and also acting on the facing end face of the plunger 19. Even when the plunger 19 is mechanically acted upon in order to transfer the toggle lever from the dead center position, the plunger 19 is subsequently moved back on account of the pressure medium supplied to the working space 35 (after the pressure medium is available again).

In Fig. 4 the reference numeral 38 denotes an interrogation device which is mounted in the head housing 5 and serves to interrogate the position of the bearing element 15 or the stop part 11.

The 5 to 7 show for the previously discussed operating states according to the 1 to 4 a working device 1 adjusted with respect to the opening angle with an opening angle of 50 °. This adjustment clearly results, for example, from the fact that the contact surfaces 12 and 14 are at a different distance from one another when the arm 2 is closed, the change in the distance corresponding to the change in the position of the stop part 11 with respect to the piston rod 7.

The embodiment according to the 8 to 13 largely corresponds to that of 1 to 7 , To avoid repetition, reference is made to the detailed description of the first exemplary embodiment.

In the embodiment according to the 8 to 13 two arms 2 are provided instead of one arm 2. The connection of the second arm is identical to the one arm according to the first exemplary embodiment, with which the bearing element 15, the articulated connector 29 and the arms 2 are arranged symmetrically to the plane running through the longitudinal axis 13 of the piston rod 7. In this respect, reference is made to the above description regarding the connection of one arm 2.

The second exemplary embodiment also differs from the first exemplary embodiment in that the respective arm 2 is modified and, moreover, the gripping element 37 is part of the second arm 2.

Fig. 8 shows the implement 1 with the two arms 2 in an open position of 90 °, Fig. 9 the intermediate position and Fig. 10 the closed position in which the two gripping elements 36 and 37 make contact.

Fig. 11 shows for the execution of the implement 1 with the two arms 2 an adjusted position of the stop part 11, so that an open position of 160 ° according to Fig. 11 reveals Fig. 12 illustrates the intermediate position and Fig. 13 shows the closed position.

The two exemplary embodiments make it clear that by simply retrofitting or supplementing the implement 1, it can be converted to the variant with one arm 2 or two arms 2. It is only necessary, starting from the variant with the one arm 2, to use a modified head housing 5 which has no receptacle for the gripping element 37 and instead to mount the two arms 2 via the toggle lever 8 in this modified head housing 5 and to the Tying bearing element 15.

LIST OF REFERENCE NUMBERS

1

implement

2

poor

3

cylinder

4

cylinder housing

5

head case

6

piston

7

piston rod

8th

toggle

9

axis

10

threaded portion

11

stop part

12

contact surface

13

longitudinal axis

14

contact surface

15

bearing element

16

admission

17

Positive engagement ring

18

ground

19

Medium / plunger

20

hexagonal recess

21

head Start

22

recess

23

axial gap

24

head

25

axis

26

Rolling element

27

bearing groove

28

admission

29

Adjustable connector

30

axis

31

axis

32

The End

33

guide

34

working space

35

working space

36

gripping element

37

gripping element

38

interrogator

39

body

Claims (13)

1. Pneumatically operable work tool (1) for use in body construction in the motor vehicle industry, with a cylinder (3) which has a cylinder housing (4), a piston (6) moveable therein and a piston rod (7) which is connected to said piston, moveable linearly and guided out of the cylinder housing (4), and with a head housing (5) connected to the cylinder housing (4), wherein a region of the piston rod (7) protruding into the head housing (5) cooperates with at least one toggle lever (8) to pivot an arm (2) assigned to the toggle lever (8), in particular a gripper arm or clamping arm, wherein this arm (2) is mounted in the head housing (5) and is pivotable between a closed position and an opened position, wherein, in the region of its end protruding into the head housing (5), the piston rod (7) receives a bearing element (15) for the toggle lever (8), wherein the bearing element (15) is guided in a guide (27) of the head housing (5) in the direction of the longitudinal axis (13) of the piston rod (7), and the bearing element (15), at a radial distance from the longitudinal axis (13) of the piston rod (7), has a receiver (28) for pivotable mounting of a hinge connector (29), which in the region of an end facing away from the bearing element (15) is connected pivotably to the arm (2) at a distance from a pivot axis (9) of the arm (2), wherein the end pivot axes (30, 31) of the hinge connector (29) and the pivot axis (9) of the arm (29) are arranged parallel to each other, wherein on its sides facing away from each other, the bearing element (15) has recesses (28) for pivotable mounting of two hinge connectors (29), characterized in that in the axial direction of the piston rod (7), the bearing element (15) has bearing parts (26) arranged behind each other and spaced apart for mounting the bearing element (15) in the head housing (5), wherein at least one receiver (28) is arranged between the bearing parts (26) in relation to the axial direction (13) of the piston rod (7).
2. Work tool according to Claim 1, characterized in that it has a single toggle lever (8) for pivoting an assigned arm (2), or two toggle levers (8, 8), wherein each of the toggle levers (8, 8) serves to pivot an arm (2) assigned to this toggle lever (8).
3. Work tool according to Claim 1 or 2, characterized in that the two hinge connectors (29) connected to the receivers (28), in the region of their ends facing away from the bearing element (15), are connected pivotably to two arms (2) at a distance from the pivot axes (9) of the arms (2), wherein the pivot axes (9, 30, 31) of the hinge connectors (29) and the arms (2) are arranged parallel to each other.
4. Work tool according to Claim 3, characterized in that the bearing element (15), the hinge connectors (29) and the arms (2) are arranged symmetrically to a plane running through the longitudinal axis (13) of the piston rod (7).
5. Work tool according to any of Claims 1 to 4, characterized in that the respective receiver (28) has a plate-like shoulder (28) connected to a base body (39) of the bearing element (15), wherein the shoulder (28) has a hole for receiving a bearing bolt (30) for the assigned hinge connector (29).
6. Work tool according to any of Claims 1 to 5, characterized in that the bearing element (15) is mounted in the guide (27) of the head housing (5) by means of a plain bearing and/or roller bearing.
7. Work tool according to any of Claims 1 to 6, characterized in that the guide (27) has parallel guide faces which are arranged parallel to the pivot axis (9) of the arm (2).
8. Work tool according to any of Claims 1 to 7, characterized in that the piston rod (7) is not variable in length and in that the opened position of the arm (2) is fully adjustable, wherein the piston rod (7) has a threaded portion (10) and in the region of the threaded portion (10) receives a buffer part (11) which is adjustable in the length direction of the piston rod (7) and, in the opened position of this arm (2), lies on a support (12) that is stationary relative to the head housing (5), and the piston rod (7) is rotatable relative to its longitudinal axis (13), wherein the piston rod (7) is rotatable relative to the bearing element (15).
9. Work tool according to Claim 8, characterized in that the buffer part (11) is positioned rotationally fixedly in the head housing (5).
10. Work tool according to Claim 8 or 9, characterized in that the stationary support (12) is formed as a support face of the head housing (5).
11. Work tool according to any of Claims 1 to 10, characterized in that in the closed position of the arm (2) or arms (2, 2), the toggle lever (8) or toggle levers (8, 8) is/are arranged in an over-dead-center position.
12. Work tool according to any of Claims 1 to 11, characterized in that a base (18) of the cylinder housing (4) facing away from the head housing (5) has means (19) for rotation of the piston rod (7) in the closed position of the arm (2) when the piston (6) is arranged in the region of the base (18).
13. Work tool according to any of Claims 1 to 12, characterized in that a base (18) of the cylinder housing (4) facing away from the head housing (5) has means (19) for axially displacing the piston rod (7) in the closed position of the arm (2) when the piston (6) is arranged in the region of the base (18), in order to move the toggle lever (8) out of an over-dead-center position.

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