EP2661410B1 - Device for lifting and transporting loads - Google Patents

Description

The invention relates to a device for transporting loads, which is attached or to be attached to another device. This device may be a stationary or movable device, wherein the movable device may be, for example, a vertically movable load carriage of an industrial truck. The device comprises at least two horizontally movable load-bearing elements, which are movable relative to each other by drive elements. The load-bearing elements are additionally guided on a common guide rail.

Such devices for receiving loads can for example be integrated in an industrial truck or designed as an attachment which is attached to a device such as a forklift or fastened. They usually have two or more mutually movable load-bearing elements, which may for example have the shape of two mutually movable forks. This mobility of the forks is achieved by appropriately trained adjusting devices and allows the users to adapt the forks to the width of a male object or to therein recesses in which engage the forks. Clamping the load between the load-bearing elements is also a possible application of such adjusting devices.

In many cases, the load-bearing elements can not only be moved towards and away from each other, but also both can be moved in parallel and simultaneously in the same direction to compensate for inaccurate truck access without much maneuvering. This side thrust movement is made possible by the same drive elements as the movement of load-bearing elements toward and away from each other. The respective adjusting devices are actuated by the operator of the truck from the workplace, without having to dismount.

Since such load-bearing devices are usually in intensive use in relatively harsh environments, the robustness of the construction is an important requirement criterion. The The load to be picked up always comes in direct contact with the device and protruding parts of the load or too rough a picking up of the load can cause damage.

The load-bearing elements can be adjusted relative to each other and are usually moved by hydraulic or electric drives. The drive elements used for this purpose represent the most sensitive components of this type of adjustment and should therefore be installed as protected as possible. In most known solutions, however, the drive elements in the form of hydraulic adjusting cylinders are mounted open. Another disadvantage of externally mounted drive elements is an impairment of the operator's view of the load-bearing elements.

In these load-receiving devices with an adjustment of the load-bearing elements basically two different types are to be distinguished. The first type is a device with telescopic guide elements, wherein the load-bearing elements can be adjusted far beyond the width of the guide structure addition. The guide construction always consists of an upper and a lower pair of telescopic rail systems, which overlap each other during extension and retraction. Known solutions of this type of load-bearing devices in which it has been attempted to incorporate the drive elements protected are, for example GB 2 207 414 A or from the European patent application EP 0 949 192 A2 , the European patent EP 0 628 511 B1 or the international patent application WO 2010/7131956 A1 known.

In the first two solutions, the cylinder housings are more or less integrated with the fixed guide structure, with the cylinder housings connected to the fixed frame and the movable piston rods driving the load-bearing members. The load-bearing elements are connected via slide rails which engage around the fixed guide construction.

In the latter solution, the piston rods are connected to the fixed guide structure, wherein the cylinder housing also function as a slide rail. A disadvantage of the latter design, however, may be that the required thick-walledness of the cylinder housing greatly reduces the adjustment force and is no longer sufficient for the side thrust movement.

A second type of these devices with an adjustment of the load-bearing elements represents a device in which the load-bearing elements can not be adjusted or only slightly or partially beyond the guide structure and thus do not require a telescopic guide device. This second type of adjusting is used in practice most often, but also applies here that the drive elements should be installed as protected as possible and the view should be reduced as little as possible. However, the adjusting devices of the first type with telescopic guide elements are too expensive and too heavy to be used as a competitive adjustment of the second type.

Known solutions of the adjusting devices in which the load-bearing elements can not be fully adjusted beyond the guide structure, are widely known, but usually consist of a simple upper and a simple lower guide and two drive elements in the form of hydraulic cylinders, which are arranged outside the guide. Such devices are for example from the German utility model DE 20 2007 006 866 U1 , the Japanese patent application JP 2000 169097 A or the European patent specification EP 1 645 536 B1 known.

Another solution is further from the US patent US 4,960,357 known, can be adjusted in the load-bearing elements within the width of the guide structure, so as to be able to accommodate loads of different dimensions. In this solution, the drive elements are installed protected in the upper guide structure. The moving sliding elements, which are connected to the load-bearing elements, are designed as a roller construction and are located outside of the fixed guide construction and embrace them. However, the height of this construction is relatively high, lateral forces on the load-bearing elements can not be intercepted and the adjustment does not use the full width of the guide structure. Furthermore, the terminals and supply lines are accommodated to the drive elements at the back of the device, whereby the construction depth of the device increases considerably.

The object of the invention is therefore to provide a device for receiving loads, which provides a good protection of the drive elements with a compact and robust construction, with the largest possible adjustment range for the load-bearing elements achieved and the disadvantages mentioned should be avoided. According to the invention, this object is achieved by a device having the features of independent claim 1. Advantageous developments of the device will become apparent from the dependent claims 2-9.

The inventive device for transporting loads according to the preamble of claim 1 provides at least two load-receiving elements, which are each mounted on a horizontally movable sliding arm, and which are movable by drive elements relative to each other, wherein the slide arms are mounted on at least one Gleitführungskörper and through the Drive elements along the at least one Gleitführungskörper are movable, and the load-receiving elements are additionally guided on a common guide rail, wherein the at least one Gleitführungskörper and the common guide rail connected by at least one connecting element and spaced from each other.

The device according to the invention is characterized in that the drive elements are at least partially in the interior of the at least one Gleitführungskörpers, and the slide arms are guided movably within the at least one Gleitführungskörpers, wherein the at least one Gleitführungskörper has at least one longitudinal slot through which a connecting portion of a sliding arm the at least one Gleitführungskörper protrudes and is connected to a load-receiving element.

In this case, during operation of the device preferably the largest part of the respective drive element lies within the at least one sliding guide body, which may include both a fixed attachment and a movable mounting within the Gleitführungskörpers. An attachment of the slide arms to movable drive elements can be realized.

The at least one Gleitführungskörper thus at least partially surrounds both the drive elements and the slide arms, so that they are advantageously protected housed in a Gleitführungskörper, which also serves to guide the slide arms. Such a protected installation of the drive and sliding elements offers great advantages, since damage and failure of the truck are reduced and the maintenance costs thus remain low. At the same time, the device can be made very compact, so as to ensure a good view from the operator to the load-bearing elements and can be produced inexpensively.

Preferably, the at least two load-receiving elements are additionally each attached to movable guide arms, which are mounted on a common guide rail.

Even if the drive elements are not telescopic, it can be provided that the slide arms and / or the guide arms protrude in the outer position of the load-receiving elements from the at least one Gleitführungskörper and / or the common guide rail. For this purpose, the width B of the load-receiving elements is less than the length L of the slide arms carried out, so that the slide arms in the inner position of the load-receiving elements also partially overlap when two Gleitführungskörper are provided.

However, the load-bearing elements preferably project less than halfway out of the guide rail or at most around the width B of the load-bearing elements. How far the load-bearing elements and / or guide arms can be extended from the guide structure depends on the one hand on the length L of the respective sliding arm, because for a stable power transmission and leadership, the slide arms and guide arms at the maximum opening sufficiently far in the Gleitführungskörper or in the guide rail remain stored. However, the possible length of the slide arms L is also determined by the desired minimum and maximum opening area of the load-bearing elements in relation to the width of the guide structure, since both the drive elements and the slide arms / guide arms must be accommodated within the width of the guide structure. The Gleitarmlänge L is thus limited compared to adjusting with telescopic, overlapping guide rails.

For the inclusion of conventional load carriers and Euro pallets, the load-bearing elements, for example, must be able to be driven quite far together, whereby the length L is limited and the load-bearing elements can be adjusted at most by the width B of the load-bearing elements outside of the guide body. In applications where the minimum clearance is greater, the slide arms and guide arms may be made slightly longer relative to the width of the slide body, and the load bearing members could still be extended slightly beyond their width B outside the guide body. If certain applications require that the load-bearing elements must be driven together, the drive element and the sliding arm / guide arm can be made so short, that the load-bearing elements for stability reasons can not protrude from the guide body.

Preferably, the at least one Gleitführungskörper and the guide rail is connected by two connecting struts with each other and spaced apart so that between the connecting struts, a Gleitführungskörper and the at least one guide rail, a viewing window is formed.

In one embodiment of the invention, a drive element comprises a cylinder which lies at least partially within a sliding guide body, and a piston rod which is movably driven in this cylinder.

The piston rod is connected to a sliding arm, wherein the cylinder, the piston rod and the sliding arm are arranged on an axis within the at least one Gleitführungskörpers. For example, the piston rod is hydraulically driven in the cylinder, and the cylinder has ports for hydraulic fluid. These connections for a hydraulic means are preferably mounted on the circumference of the cylinder and led out in the direction of the main plane of the device from a Gleitführungskörper. This arrangement has the advantage that the connections and hoses located thereon can be led out of a sliding guide body at the top and bottom in a space-saving manner without adversely increasing the design depth of the device and impairing the operator's vision.

Preferably, at least one recess in the sliding guide body is provided in the region of the connections for the hydraulic medium transversely to the longitudinal slot, through which the connections are guided. The cylinder is also detachably mounted in the sliding guide body, so that it can be rotated together with the terminals after a release and pulled out of a Gleitführungskörper.

In one embodiment of the invention, the connection between the piston rod and the slide arm is located inside the slide arm. This has the advantage that the sliding arm can be made longer and provides better guidance, as if the connection is attached to the outside of the sliding arm or another connecting element between the sliding arm and piston rod would be provided. Such an external junction would also be more unstable.

Preferably, two Gleitführungskörper are provided in each of which a drive element is located and a sliding arm is mounted. As a result, the construction is much stiffer and more robust than, for example, those of the US patent US4,960,357 known design. The two guide arms can also be guided in each case in a guide rail or together in a guide rail. In this case, the two sliding guide bodies are arranged one above the other in a preferred embodiment. In a particularly preferred embodiment, the two Gleitführungskörper are interconnected.

The load-bearing elements can be supported directly on the common guide rail even without guide arms.

Further advantages, features and expedient developments of the invention will become apparent from the dependent claims and the following description of preferred embodiments with reference to the drawings.

Fig. 1

eine dreidimensionale Vorderansicht eines Ausführungsbeispiels der erfindungsgemäßen Vorrichtung mit Lastaufnahmeelementen in Außenstellung;

Fig. 2

das Ausführungsbeispiel der Figur 1 mit Lastaufnahmeelementen in Innenstellung;

Fig. 3

eine Frontansicht des Ausführungsbeispiels der Figur 1; und

Fig. 4

eine Seitenansicht des Ausführungsbeispiels der Figur 1.

From the pictures shows:

Fig. 1

a three-dimensional front view of an embodiment of the device according to the invention with load-receiving elements in the outer position;

Fig. 2

the embodiment of FIG. 1 with load-bearing elements in the inner position;

Fig. 3

a front view of the embodiment of FIG. 1 ; and

Fig. 4

a side view of the embodiment of FIG. 1 ,

FIG. 1 shows an embodiment of the device according to the invention for receiving and transporting loads in a three-dimensional front view, wherein FIG. 3 additionally shows a front view of this embodiment, and individual parts are better to be inferred due to the perspective of each of the figures. The device 10 is preferably designed as an attachment for a not shown, vertically movable load carriage, which is located on an industrial truck such as a forklift. The device can be mounted on this load carriage and dismantled if necessary another attachment should be used. However, the device may also be firmly integrated into a load carriage or an industrial truck or also be attached to a stationary device, wherein the connection to a stationary device may be fixed or only temporary.

The device comprises at least two load-receiving elements 20, 21, which may be designed, for example, as forks. These load-bearing elements 20, 21 are horizontally movable in different positions, which is achieved by a Gleitführungskonstruktion and drives with which both forks are moved separately. However, the drives of the two load-receiving elements can also be synchronized. In the FIG. 1 For example, the load-bearing elements 20, 21 are shown in the outer position, in which both forks are in their outermost position.

The forks are connected to slide arms 30, 31, which are movably guided in each case in a sliding guide body 50, 51. The two Gleitführungskörper 50, 51 are arranged one above the other and formed as profiles, which are preferably hollow cylindrical inside. The essentially cylindrical slide arms can thus be movably mounted in the interior of the slide guide bodies 50, 51.

The two Gleitführungsprofile 50, 51 are connected to each other and their outer contour is preferably rectangular, so that they form a rear surface with which the device 10 can be attached by suitable means on the load carriage of a truck. This structure is also the side view of FIG. 4 can be seen in which a plurality of attachment hooks 110, 101 are attached to the rear side of the device as a means for attaching the device 10 to a load carriage. Preferably, there are corresponding attachment hooks both on the Gleitführungskörpern 50, 51 and on the lower guide rail 70.

The Gleitführungskörper 50, 51 further each have at least one longitudinal slot 52, 53, which preferably extends forward over the entire length of each Gleitführungskörpers. However, the longitudinal slot can also be executed interrupted. However, at least in the area of the slide guide body in which the slide arms move horizontally with the load receiving members 20, 21, a longitudinal slot is inserted in each slide guide body such that a connecting portion 32, 33 of each Sliding arm 30, 31 protrudes through the longitudinal section and is connected outside the Gleitführungskörpers with a load-receiving element.

The Gleitführungskörper 50,51 can also be designed so that a longitudinal slot for the first load-receiving element is located in the upper region and facing upward, while a longitudinal slot for the second load-receiving element facing downward. The front side of the entire Gleitführungskörpers would thus be completely closed and for the connections of the drive means would have to be provided in this case no separate recess.

The load-bearing elements slide in their movement along the Gleitführungskörpern along and are held by the slide arms in the Gleitführungskörpern. In this case, the load receiving elements 20, 21 may be integrally formed with the slide arms 30, 31, be welded to them or releasably connected, for example via a screw connection with them.

The horizontal movement of the slide arms 30, 31 and thus the load-bearing elements 20, 21 is effected by two drive elements which are arranged within the Gleitführungskörper. These are, for example, hydraulic cylinders 40, 41, which are arranged in the Gleitführungskörpern. In the cylinders in each case a piston rod 42, 43 is movably guided, wherein the piston rod 42, 43 is connected in each case with a sliding arm. The movement of a piston rod out of a cylinder or into a cylinder thus causes a movement of the slide arms and thus the load-bearing elements.

The connection of the piston rods 42, 43 with the slide arms 30, 31 is preferably within the slide arms, wherein the connection can be made in various ways. For example, a sliding arm can be formed from a tubular profile into which the piston rod is introduced and fixed there. However, the sliding arm can also be formed from a solid profile, in which then a cavity for introducing the piston rod is introduced. In this case, a screw introduced from the front through the opening of the longitudinal slot can connect the piston rod to the sliding arm. Preferably, the connection is made easily movable, so that slight rotations of the slide arm in the guide body, the seals of the hydraulic cylinder in the area of the piston rods as little as possible burden.

The width B of the load-bearing elements is preferably less than the length L of a sliding arm, so that the load-receiving elements 20, 21 in their outer position as in FIG. 1 can easily protrude beyond the ends of the Gleitführungskörper 50, 51, while the thereto located slide arms 30, 31 are still performed within the Gleitführungskörper. For this purpose, the slide arms 30, 31 protrude slightly out of the Gleitführungskörpern out, but are still with a much larger section within the Gleitführungskörper. The maximum external position of the load-bearing elements 20, 21 is thus not necessarily limited by the total length of the Gleitführungskörper.

At a distance from the Gleitführungskörpern 50, 51 at least one guide rail 70 is attached, which is connected via a connecting element with the Gleitführungskörpern. Preferably, the connecting element is at least two vertical connecting struts 80, 81, which extend between the Gleitführungskörpern 50, 51 and the guide rail 70 and are horizontally spaced apart so that between the connecting struts 80, 81, the Gleitführungskörpern 50, 51st and the guide rail 70 provides a viewing window for the operator of the device. The connecting struts 80, 81 are preferably designed so that the construction depth of the device 10 is not increased by them, ie they are, for example, as in the embodiment of FIG. 1 attached to the bottom of the Gleitführungskörpern 50, 51 and the top of the guide rail 70, while an attachment at the rear of these components would increase the depth of construction.

The load receiving elements 20, 21 are guided via guide arms 60, 61 on the guide rail 70, wherein the guide rail 70 may be formed as the Gleitführungskörper 50, 51 as a hollow cylinder, so that the guide arms 60, 61 analogous to the slide arms 30, 31 also cylindrical can be formed. In the guide rail 70 is then also a longitudinal slot (without reference numeral), project through the connecting portions of the guide arms 60, 61 and connected to the load-receiving elements 20, 21. However, the guide rail 70 may also be designed differently than the sliding guide body, as long as it ensures a guide of the load-receiving elements 20, 21 in the lower region of the device 10.

If it is provided that the load-bearing elements 20, 21 are to be movable outward beyond the sliding guide construction, the guide rail 70 should be designed to be load-bearing. If this is not intended, would as a guide rail 70th For example, sufficient a simple bar on which the load-bearing elements 20, 21 are supported without the help of guide arms.

Preferably, a wear bush is provided within the sliding guide body 50, 51 at least in the range of movement of the slide arms 30, 31. However, the wear bush extends only to the cylinders 40, 41, in the area no closure sleeve is required. Thus, the cylinders 40, 41 can be made as large as possible in diameter and thus generate sufficient force to be able to move the load-bearing elements 20, 21 together, for example, with a load in parallel (side thrust function) or to be able to clamp a load.

FIG. 2 shows the device 10 of the embodiment of FIG. 1 with the load-bearing elements 20, 21 in the inner position, wherein in particular it is apparent that a Gleitführungskonstruktion with two Gleitführungskörpern compared to only one Gleitführungskörper brings the advantage that the slide arms 30, 31 can easily overlap in the inner position. So they can run longer than a single Gleitführungskörper and thus provide better guidance. Further, a pair of sliding guide bodies offer higher rigidity and stability than solutions in which a plurality of drives are housed together in a sliding guide body.

For reasons of stability and to reduce the manufacturing costs, the guide bodies over the entire width of the device preferably have the same shape, ie the same cross section. Thus, the Gleitführungskörper can be easily manufactured in the desired length and the individual components are mounted in them or on them. The area of a Gleitführungskörpers in which a sliding arm moves and the area of the Gleitführungskörpers in which the drive elements are installed, but need not necessarily have the same design. In the guide region of the slide arms, the slide arms are slidably mounted in the inner region of the Gleitführungskörpers and also must be room for the driving piston rod. The region of the Gleitführungskörpers, in which the hydraulic cylinders are mounted, must be able to absorb these drive elements, wherein the Gleitführungskörper in this area, the hydraulic cylinders or drive elements at least partially surrounded. However, both areas can have different designs, which can be adapted to the respective requirements.

As a drive cylinder 40, 41 standard hydraulic cylinders can be used for the supply of hydraulic fluid preferably at the periphery of the cylinder 40, 41 several connections are provided for the supply and discharge of hydraulic fluid. The terminals 44, 44 ', 45, 45' are preferably arranged so that the feeds are in the direction of the main plane of the device. The main plane of the device is the plane in which the Gleitführungskörper, the guide rail and the connecting struts are, so that the hydraulic fluid is discharged upwards or downwards or fed from there. This has the advantage that the construction depth of the device is not increased by the hoses and the feeds protected above and below the Gleitführungskörpern along can be performed.

The drive cylinders 40, 41 are preferably connected at the bottom side via a bolt oscillating with the Gleitführungskörpern 50, 51. This movable connection can be used to avoid high stresses on the seals of the drive cylinder in the region of the piston rods.

Preferably, transverse to the longitudinal slot 52, 53 of each Gleitführungskörpers recesses 54, 55, 56, 57 in the upper and lower portions of the Gleitführungskörper. Through these recesses, the connections for the hydraulic fluid can be led to the outside. For disassembly of the drive cylinder, the connections are released and the cylinders can be rotated by loosening their fastening bolts by 90 degrees, so that the connections can come to rest in the longitudinal slot of the Gleitführungskörper. The respective cylinder can then be pulled out of the Gleitführungskörper. When mounting a drive cylinder, these steps are done in reverse order.

In the middle of the sliding guide bodies 50, 51, an oil feedthrough block 90 can be mounted, which extends vertically over both Gleitführungskörper and beyond. Via this oil passage block 90, hoses may be led up from the ports 45, 45 'of the lower drive cylinder 41 for connection with the tubes of the upper drive cylinder 40, being guided closely along the slide guide bodies (not shown). The oil passage block 90 also serves as protection for the piston rods 42, 43. Above the hoses of the lower and the upper drive cylinder are brought together in a synchronizing valve, also not shown. The synchronizing valve serves to move both load-receiving elements 20, 21 relative to one another at the same speed.

In the region of the middle terminals 44 'and 45' of the two cylinders 40, 41, two protective elements 91, 92 are preferably mounted. These can be welded to the Gleitführungskörper and compensate for one hand, the weakening of the profile through the recesses 55 and 56. On the other hand, they also visually close the recesses and protect the connections and hoses behind them against damage. Such protective elements could also be provided on the outer terminals 44 and 45, but the weakening of the profile in the outer area is less relevant.

The FIGS. 1 to 4 show an embodiment of the invention, in which the drive elements are formed by a drive cylinder and an associated piston rod, each drive cylinder with the associated Gleitführungskörper is fixed or oscillating, while a load-receiving element is attached via a sliding arm on a piston rod and thus along the Gleitführungskörpers is mobile. However, the invention can also be realized by a reverse construction by attaching a load receiving member to a sliding arm, which in turn is attached to a drive cylinder. The drive cylinder forms the sliding arm or a part of it and is movable within a Gleitführungskörpers when the end of the associated piston rod is fixed or resiliently mounted on the Gleitführungskörper. In the figures, the at least one sliding guide body is shown at the upper end of the device, while the common guide rail is arranged at the lower end, so that the Gleitführungskörper is arranged above the guide rail. The invention is not limited to such an arrangement. The guide rail can also be arranged above the Gleitführungskörpers.

LIST OF REFERENCE NUMBERS

10

Load-carrying device

20.21

Load-bearing element, fork tine

30.31

sliding arm

32.33

Connecting portion of a sliding arm

40.41

Drive element, cylinder

42.43

piston rod

44.44 '45.45'

connection

50.51

Gleitführungskörper

52.53

longitudinal slot

54,55,56,57

recess

60.61

guide

70

guide rail

80.81

Connecting element, connecting strut

90

Oil passage block

91.92

protection element

100,101

fastening hooks

Claims (12)

1. A device for transporting loads, comprising at least two load lifting elements (20; 21) that are each installed on horizontally movable sliding arms (30; 31) and that can be moved relative to each other by drive elements, whereby the sliding arms (30; 31) are mounted on at least one sliding guide member (50; 51) and can be moved by the drive elements along the at least one sliding guide member (50; 51), and the load lifting elements (20; 21) are additionally guided on a shared guide rail (70), whereby the at least one sliding guide member (50; 51) and the shared guide rail (70) are joined to each other by means of at least one connecting element (80; 81) and are situated at a distance from each other,
   characterized in that
   the drive elements are at least partially inside the at least one sliding guide member (50; 51), and the sliding arms (30; 31) are guided movably inside the at least one sliding guide member (50; 51), whereby the at least one sliding guide member (50; 51) has at least one elongated slot (52; 53) through which a connecting section (32; 33) of a sliding arm (30; 31) projects out of the at least one sliding guide member (50; 51) and is connected to a load lifting element (20; 21).
2. The device according to claim 1,
   characterized in that
   the at least two load lifting elements (20; 21) are each additionally installed on movable guide arms (60; 61) that are mounted on a shared guide rail (70).
3. The device according to claim 1 or 2,
   characterized in that,
   when the load lifting elements (20; 21) are in the outer position, the sliding arms (30; 31) and/or the guide arms (60; 61) project out of the at least one sliding guide member (50; 51) and/or out of the shared guide rail (70) at the maximum by the width B of the load lifting elements (20; 21).
4. The device according to one of claims 1 to 3,
   characterized in that
   the width B of the load lifting elements (20; 21) is less than the length L of the sliding arms (30; 31), and in that, when the load lifting elements (20; 21) are in the inner position, the sliding arms (30; 31) overlap in certain areas.
5. The device according to one of claims 1 to 4,
   characterized in that
   the at least one sliding guide member (50; 51) and the shared guide rail (70) are connected to each other by two connecting struts (80; 81) and are at a distance from each other in such a way that a viewing window is formed between the connecting struts (80; 81), the at least one sliding guide member (50; 51) and the shared guide rail (70).
6. The device according to one of claims 1 to 5,
   characterized in that
   a drive element comprises a cylinder (40; 41) that is situated, at least partially, inside the at least one sliding guide member (50; 51), and a piston rod (42; 43) is movably driven in the cylinder (40; 41) and is connected to a sliding arm (30; 31), whereby the cylinder (40; 41), the piston rod (42; 43) and the sliding arm (30; 31) are arranged on an axis inside the at least one sliding guide member (50; 51).
7. The device according to claim 6,
   characterized in that
   the piston rod (42, 43) is hydraulically driven in the cylinder (40; 41), and the cylinder (40; 41) has connections (44; 45) for a hydraulic medium.
8. The device according to claim 7,
   characterized in that
   the connections (44; 45) for a hydraulic medium are installed on the circumference of the cylinder (40; 41) and they extend out of a sliding guide member (50; 51) in the direction of the main plane of the device.
9. The device according to one of claims 7 or 8,
   characterized in that,
   in the area of the connections (44; 45) for the hydraulic medium, crosswise to the elongated slot (52; 53), there is at least one recess (54; 55; 56; 57) in the sliding guide member (50; 51) through which the connections (44; 45) pass, and in that the cylinder (40; 41) is detachably installed in the sliding guide member (50; 51).
10. The device according to one of claims 6 to 9,
    characterized in that
    the connection between the piston rod (42; 43) and the sliding arm (30; 31) is located inside the sliding arm (30; 31).
11. The device according to one of the preceding claims,
    characterized in that
    each sliding arm (30; 31) is mounted with the appertaining drive element inside its own sliding guide member (50; 51).
12. The device according to claim 11,
    characterized in that
    the two sliding guide members (50; 51) are arranged one above the other and are connected to each other.

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