EP1024109B1 - Attachment for industrial trucks with a mast, in particular for forklift-trucks - Google Patents

Abstract

The additional equipment has a hydraulically driven element mounted on two horizontal bearers (12,13) on the lifting pillar with an associated hydraulic drive (14) and control unit (18). The hydraulic drive, control element and drive elements (19a,19b) are at least partly arranged in a space (7) bounded by vertical planes contg. the front of the horizontal bearers and the rear edges of the side walls (9,10) of the lifting carriage (8).

Description

The invention relates to an attachment for industrial trucks with a mast.

The subject of the invention can be used advantageously in industrial trucks with attachments with hydraulic self-propulsion, as for Forklifts are described in VDI Guideline No. 3578. After that are attachments additional devices that are used for load handling, transport protection or load movement can be used. Such devices are used for Carrying loads from above, in the middle and / or from below, for clinging, Turning, pulling and lifting the load, for tipping sideways, forwards and backwards, for pushing the load forward and across, for holding the load from above and / or from the side and to adjust the fork spacing. The following are described as loads: paper rolls, concrete pipes, barrels, Bales, box-packed goods, stones, containers and boxes, foundry inserts and bulk goods. Due to the depth, the so-called stem dimension, and the dead weight of the attachment becomes the load capacity of the Vehicle reduced. This requires a reduction in the above Sizes.

As industrial trucks, VDI guidelines no.3586 include stated all funds moving on the floor (corridor), which are in the in-house Transport of their type after transport, pulling, pushing, Lifting, stacking or on-shelf storage of loads of all kinds that serve driverless, pedestrian-controlled, or driven by a driver who is sitting or standing on the industrial truck or lifting driver's seat.

So-called are usually between the vehicle and the attachment Interfaces arranged according to VDI guidelines No. 3642. This Guidelines regulate the range of hydraulic pressures and flow rates as well as the dimensions and arrangement of hydraulic couplings. As a result, the weight of the attachment becomes necessary and further reduced the load capacity of the vehicle and above all that Costs increased. The subject of the invention is not only for special advantages Sideshift devices, but also for attachments or attachments according to DE 31 25 384 C2 and DE 40 41 846 A1 the same Applicant suitable for attachments for forklifts at which the forks are hydraulically symmetrical transverse to their longitudinal direction are movable. In the DE 31 25 384 C2, the forks are also still individually and additionally extendable in their longitudinal directions, what additional hydraulic drives required. Side shifting devices are known for the asymmetrical shifting of the load, namely either to compensate for driving or positioning errors or - after the swiveling of the forks by 90 degrees - to insert the Load left or right on storage racks. For each individual drive to provide the necessary hydraulic hoses, resulting in whole "hose trees" leads.

Sideshift devices that belong to the attachments are by DE 196 02 055 C1 and DE 196 02 553 A1 of the same Applicant known, they are completely hydraulic via appropriate Valves controlled from the vehicle.

For this purpose, the vehicle has an appropriate number of hydraulic pressure hoses connected to the sideshift drive, and since these pressure hoses cover the entire stroke of the lifting carriage must have an appropriate length and are in Zigzag shape over pulleys partly on the rear of the mast, partly between the profiles of the mast and partly also guided between the side walls of the lifting carriage. At the height of Masts e.g. for order picking stackers six and more meters As a result, considerable hose lengths are required. This has a number of disadvantages:

Such pressure hoses laid over deflection rollers are subject to one high wear. Therefore, DIN 20066, Part 5, contains those for hose assemblies of fluid technology, note that the period of use including a possible storage period for hose lines Art should not exceed the period of six years and that the Storage period should not exceed two years. This makes of From time to time an exchange of the expensive pressure hoses with everyone Problems with venting and filling the entire hydraulic Systems with corresponding follow-up costs required.

Another problem resides in the possibility that in such a long time Hoses create air cushions that significantly impair the function, because they lead to jerky movements of the sideshift can. Think of a load that is in several meters Located above the ground on the mast of a forklift and through jerky movements of the sideshift drive to horizontal Rocking movements is stimulated.

US Pat. No. 4,618,306 is a front-end device designed as a structural unit known for tipping barrels, which consists of two hollow side members exists, which is rigidly connected to each other by a base plate are. On this base plate is inside a large volume Housing a complete hydraulic drive unit with accumulators, Electric motor, hydraulic pump, oil pan and control unit. This The drive unit is only connected to the electrical control lines Vehicle connected, on the dashboard of the electrical control switch can be detachably attached, but is completely in front of the lifting carriage. Due to the considerable depth of the drive unit the forks must be made longer, and it gets the center of gravity very far towards the forks laid at the front so that the entire arrangement is top-heavy. Come in addition nor that in front of the drive unit, a drive cylinder for a rotary movement a clamp for the barrels on one of the hollow side members is attached. This drive cylinder also shifts the center of gravity of the front-end device even further forward. To record this The vehicle's lifting forks are placed in the hollow side members retracted, i.e. also the masses of lifting forks and side members add up to one with the distance of the load from the lifting carriage considerable overturning moment. The device has no sideshift device.

From DE 44 15 429 C2 it is with a mounting device with a Sideshift device for forklift known, one on two lifting forks Postpone turning device for precast concrete. The one of these turning devices has a hydraulic drive that acts on a pivot bearing, the other a pivot bearing, which is only an automatic reset device having. Each of the pivot bearings has a shoe-shaped one Basic body or side member into which one of the lifting forks is inserted becomes. The hydraulic drive is via quick couplings to the hydraulic system of the vehicle, and the hydraulic lines are guided over the mast. The drive system of the rotating device is so not self-sufficient. The reference to one from the truck hydraulics independent rotary drive does not say anything about their spatial Accommodation. All rotary actuators and their components as well as those on the Forks slid on shoe-shaped base or side members are completely in front of the lifting carriage. Here too, through the considerable depth of the hydraulic drive on one of the forks of the Center of gravity very far forward in the direction of the fork tines, see above that the entire arrangement is top-heavy. In particular, also shifts this hydraulic drive further increases the focus of the front attachment forward. The lifting forks of the Vehicle retracted into the longitudinal beams of the rotary drives, i.e. also the Masses of longer lifting forks and side members add up with the Distance of the load from the lifting carriage to a considerable tipping moment.

The US-A 4 902 190, which corresponds to the closest prior art, has set the goal, the stem size and the To keep the top heaviness of a fork stem as low as possible. This succeeds but only to a very limited extent because there are three complete frames, namely a lifting slide, a side shift support frame and a very deep, U-shaped sideshift frame open at the bottom. whose edges up pulled forward to the front surfaces of the vertical fork legs are. Within the depth of the sideshift support frame and sideshift frame there are two horizontal drives, namely above the ends of the vertical fork legs a motor with a threaded spindle for a symmetrical adjustment of the distance between the forks. The The motor can be either an electric motor or a hydraulic motor. For A hydraulic motor is provided with a hydraulic valve Driver is operated, in turn two hydraulic hoses via the Lift mast conditional. As it is common to use the symmetrical fork adjustment Unloaded forks can make the engine very weak his. Nevertheless, the volume and top heaviness are up and enlarged at the front, because the above drive elements are included at least half of their depth before the front level of the Sideshift support frame arranged, which is only due to the shift motor and threaded spindle up and forward was possible. Otherwise the adjustment of the forks would have been impossible. Within the Sideshift support frame is a much stronger, double acting Hydraulic cylinder provided, the pressure lines not shown and are not described, but which are available and also via the Lift mast must be performed. Also on the presence of one Control unit for the hydraulic cylinder in the attachment can from the Revelation cannot be closed. So that the following can Invention task can not be completely solved.

In contrast, the invention is based on the task of laying to avoid hydraulic pressure hoses over the mast for which Drive the attachments as small and light hydraulic elements as possible with the lowest possible energy consumption and the tilting moment known hydraulic units and / or hydraulic components reduce the stability of the vehicle.

The solution to the problem is the one specified at the beginning Implement according to the invention by the features in claim 1.

The invention makes it possible to lay hydraulic pressure hoses to dispense with the mast and for the drive the attachments small and light hydraulic elements with low Use energy needs. An extension of the forks is not required, and the top heaviness is compared to that in State of the art significantly reduced.

Compared to US Pat. No. 4,902,190, only two frame elements are used needed, namely the lifting slide, which consists of two side walls and two horizontal beams lying one above the other, and from the side shift frame, which consists of two vertical struts, which are separated by one upper horizontal rail and a lower horizontal rail connected are. These horizontal rails are made direct by means of the horizontal beams guided. Between the lifting slide and the side shift frame there is no other frame. This will decrease continue the number of parts, the manufacturing costs, the depth and that Stem dimension together with the weight and the resulting Tilting moment. All hydraulic elements from the group of pumps and the control units are only behind the front one Level.

Gear pumps are preferably used as hydraulic pumps, because they are small and inexpensive; but also axial piston or diaphragm pumps, since these are also driven by solenoid coils can be.

The control can be carried out from the vehicle using multi-core power cables, but can also be done wirelessly via a radio remote control, whose Transmitter can be operated from the vehicle. In this case it is particularly advantageous if the control unit has a power store assigned, which also supplies the electricity for the pump drive.

• die Steuereinheit starr mit dem mindestens einen Hydraulikantrieb verbunden ist,
• bei Anordnung eines Seitenschieberrahmens für Gabelzinken an den Horizontalträgern der Seitenschieberrahmen seinerseits zwei übereinanderliegende Horizontalschienen besitzt, die längsverschiebbar an den Horizontalträgern des Hubschlittens geführt sind, und daß der Hydraulikantrieb und die zugehörigen Steuereinheit für die Horizontalverschiebung des Seitenschieberrahmens zwischen den besagten Ebenen angeordnet ist,
• der Hydraulikantrieb einen Doppelzylinder mit gleichsinnig bewegbaren Kolben aufweist und wenn die Steuereinheit ein Wegeventil ist, durch das die Druckseite einer Hydraulikpumpe nach Maßgabe der Verschieberichtung dem einen oder dem anderen Kolben aufschaltbar ist,
• in der Druckleitung zwischen der Druckseite der Hydraulikpumpe und der Steuereinheit ein Druckspeicher angeordnet ist,
• die Druckseite der Hydraulikpumpe einem Druckschalter aufgeschaltet ist, durch den nach Erreichen eines vorgegebenen Drucks im Druckspeicher die Hydraulikpumpe stillsetzbar ist, und/oder, wenn
• der Hydraulikantrieb einen Doppelzylinder mit gleichsinnig bewegbaren Kolben aufweist, wenn die Förderrichtung der Hydraulikpumpe umkehrbar ist und wenn die Steuereinheit ein Wegeventil und zwei entgegengesetzt geschaltete Druckbegrenzungsventile aufweist.

It is particularly advantageous if - either individually or in combination:

• the control unit is rigidly connected to the at least one hydraulic drive,
• when a sideshift frame for forks is arranged on the horizontal supports, the sideshift frame in turn has two superimposed horizontal rails which are longitudinally displaceably guided on the horizontal supports of the lifting carriage, and that the hydraulic drive and the associated control unit for the horizontal displacement of the sideshift frame is arranged between the said levels,
• the hydraulic drive has a double cylinder with pistons which can be moved in the same direction and if the control unit is a directional valve through which the pressure side of a hydraulic pump can be connected to one or the other piston in accordance with the direction of displacement,
• a pressure accumulator is arranged in the pressure line between the pressure side of the hydraulic pump and the control unit,
• the pressure side of the hydraulic pump is connected to a pressure switch, by means of which the hydraulic pump can be stopped after reaching a predetermined pressure in the pressure accumulator, and / or if
• the hydraulic drive has a double cylinder with pistons which can be moved in the same direction if the delivery direction of the hydraulic pump is reversible and if the control unit has a directional control valve and two pressure relief valves connected in opposite directions.

The additional advantages are in the detailed description below specified, which relates to details of a sideshift device, without being limited to this.

Exemplary embodiments of the subject matter of the invention are as follows explained in more detail with reference to Figures 1 to 6.

Figur 1

eine perspektivische Darstellung eines ersten Ausführungsbeispiels einer Baugruppe aus Hubschlitten, Seitenschieberrahmen und horizontal wirkendem Hydraulikantrieb, jedoch ohne Steuereinheit und Druckmittelversorgung, in einer Ansicht von schräg hinten,

Figur 2

eine teilweise geschnittene rückseitige Ansicht eines zweiten Ausführungsbeispiels einer Baugruppe aus Hubschlitten, Seitenschieberrahmen und horizontalwirkendem Hydraulikantrieb mit Steuereinheit und Druckmittelversorgung,

Figur 3

eine Seitenansicht des Gegenstandes von Figur 2 in Richtung des Pfeils III in Figur 2 in vergrößertem Maßstab mit aufgesetzten Gabeln, von denen nur die vordere sichtbar ist,

Figur 3a

den Gegenstand von Figur 3 ohne aufgesetzte Gabeln, jedoch mit einem schraffiert eingezeichneten Bereich für die Unterbringung zumindest der wesentlichen schweren Teile des Hydraulikantriebs, und

Figuren 4 bis 6

Verschiedene Hydraulikschaltungen mit Steuereinheiten und Druckmittelversorgungseinheiten.

Show it:

Figure 1

1 shows a perspective view of a first exemplary embodiment of an assembly comprising a lifting slide, side shift frame and horizontally acting hydraulic drive, but without a control unit and pressure medium supply, in an oblique view,

Figure 2

3 shows a partially sectioned rear view of a second exemplary embodiment of an assembly comprising a lifting slide, side shift frame and horizontally acting hydraulic drive with control unit and pressure medium supply,

Figure 3

3 shows a side view of the object from FIG. 2 in the direction of arrow III in FIG. 2 on an enlarged scale with forks attached, only the front of which is visible,

Figure 3a

the object of Figure 3 without attached forks, but with a hatched area for accommodating at least the essential heavy parts of the hydraulic drive, and

Figures 4 to 6

Various hydraulic circuits with control units and pressure medium supply units.

Figure 1 is essentially the structural requirements for the accommodation of control unit and pressure medium supply: On Sideshift frame 1 consists essentially of an upper horizontal rail 2, a lower horizontal rail 3 and two straight lines Vertical struts 4 and 5. The upper horizontal rail 2 is with notches 6 for the form-fitting hanging from not shown here Provide forks. The horizontal rails 2 and 3 are on their mutually facing sides U-shaped and defined by their vertical outer sides two vertical and transverse to the direction of travel running virtual plane-parallel planes E1 and E2, the spacing of which Profile width of the horizontal rails 2 and 3 corresponds.

As far as above and below the terms "vertical" or "vertical" are used, these terms are not strictly geometric, because deviations from this result from a work-related inclination of the mast can result and also result. The reference to "Front" and "rear" are based on the direction of travel of the vehicle to which the sideshift device is attached.

The side shift frame 1 is guided on a lifting slide 8, which also can be referred to as equipment carrier and two plate-shaped side walls 9 and 10, the rear edges of which have a third virtual and vertical Level "E3" that go to the first and second levels E1 and E2 again runs parallel. These levels are important tools for the determination of the definitions according to the invention, which is based on the Figures 1 and 3 is clarified. The through the levels E1 and E3 in Direction of travel of the truck, not shown, defined space 7 at least partially to accommodate at least a portion of the below hydraulic elements described in more detail. Preferably can these can also be accommodated in that part of room 7 which lies between levels E1 and E2, through the front and back of the sideshift frame.

On the outer surfaces of the side cheeks 9 and 10 are 11 stub axles Fixed guide rollers, by means of which the lifting carriage 8 in vertical Direction is guided on a mast not shown. The sidewalls 9 and 10 are at a clear distance "h" by an upper horizontal beam 12 and a lower horizontal beam 13 connected, the upper horizontal beam 12 in a unit with a double-acting Hydraulic drive 14 is designed so that these parts are mutually stiffen and reinforce. The horizontal beams 12 and 13 are behind both sides clearly above the side cheeks 9 and 10.

The upper sliding surface of the horizontal beam, equipped with sliding bodies 12 is through the upper horizontal rail 2 of the side shift frame 1st hidden and therefore shown in dashed lines. The hydraulic drive 14 has two pistons 15 and 16, which are designed as plungers and to which Bump vertical struts 4 and 5 of sideshift frame 1. The extendable length of the pistons 15 and 16 determines the maximum horizontal travel of the sideshift frame 1. This maximum Starting from a middle position, travel can be between 50 and Be 250 mm on both sides.

Details of such side shift devices are in the DE 196 02 055 C1 and described in DE 196 02 553 A1, so that here in-depth explanations can be dispensed with.

The two ends of the lower horizontal support 13 are with support rollers 17th provided, on which the front leg of the lower horizontal rail 3 of the sideshift frame 1 is supported. Their rear legs is milled at both ends in the range of movement of the support rollers 17. The horizontal beams 12 (with the hydraulic drive 14) and 13 are also located at least essentially between the imaginary, by definition Levels E1 and E2.

In Figures 2, 3 and 3a are for the same parts or parts with the same Function uses the same reference numerals. In contrast to the figure 1 are the straight vertical struts 4 and 5 by mirror symmetry offset vertical struts 4a and 5a replaced.

In the forward through the levels E1 and E2 (see Figures 1, 3 and 3a) and at the back limited room 7 is - from top to bottom - First of all, the double-acting hydraulic drive 14 with a continuous or one-piece cylinder body 14a and the two Pistons 15 and 16. The inner ends of the numbered cylinder bores have the smallest possible axial distance from each other, such as this is also shown in DE 196 02 055 C1 and in DE 196 02 553 A1 is. In the present case, however, the radial connection holes were also relocated as close as possible to each other so that a control unit 18 in the form of an electromagnetically actuated directional valve with the magnetic drives 18a and 18b and three switching positions immediately, i.e. without the interposition of pressure hoses to the Hydraulic drive 14 could be flanged.

Below and within the room 7 there is again a pump block 19 with a hydraulic pump 19a and an electric motor 19b. The Pump sump and a tank are not particularly shown in Figure 2, but are also in room 7. Reference is made to FIGS. 4 to 6. Also the electrical lines for the control unit 18 and the pump motor 19b are not shown.

The latitude (transverse to the direction of travel) of control unit 18 and Pump block 19 is not on the clear distance of the side cheeks 9 and 10 limited; it is only necessary to ensure that the vertical struts 4 / 4a and 5 / 5a cannot touch anywhere.

Between the control unit 18 and the pump block 19, in a further embodiment of the invention - the management of a pressure accumulator 20 flow into. The pressure accumulator can, since it does not have a long pressure line requires, also arranged outside the room 7 on the lifting carriage as shown in Figure 2. The pressure accumulator brings the following Advantage with it: Since it also during the breaks in the side shift movement, can be charged over long periods of time the performance of the pump block 19 and thus its dimensions be reduced. This happens in borderline housing cases the other hydraulic elements in room 7 significantly counter. Also for the case of the use of power storage (accumulators) arise Advantages when using a pressure accumulator.

Exceeding the depth of the room 7 by the dimensions of the individual hydraulic elements are approved and also as long as not critical, like not having a mutual disability and / or a touch with other construction elements occurs. For example, it is possible also part of the depth of the space between the side cheeks 9 and 10 for the accommodation of hydraulic elements.

Such a possibility is explained with reference to FIG. 3: in the side cheek 9 of the lifting carriage 1 is located between the stub axles 11 a drive roller 21, which by the vertical movement of the lifting carriage 1 is driven relative to the mast, not shown, namely either by friction or by positive engagement, for example by Intervention in a rack or roller chain, both not shown. The Rotational movement of the drive roller 21 can either be directly on a Hydraulic pump 22 are transmitted, or by transmission means 23rd to a pump operating within space 7 between levels E1 and E2 is housed. One of the forks 36 is on by means of hooks 36a and 36b the horizontal rails 2 and 3 removably attached.

FIG. 3a shows the object from FIG. 3 without forks attached, but with a hatched area for the accommodation at least the essential heavy parts of the hydraulic drive.

The single-acting hydraulic drives 14 are shown in FIGS. 4 to 6 Disc pistons and piston rods are shown, but this is not fundamental changes in the building principle. The control units are shown in FIGS 18 designed and shown as directional control valves with three switching positions. In Figure 6, the control unit 24 consists of a magnetically controlled Directional control valve 25 with two switch positions and two anti-parallel switched directly controlled pressure relief valves 26 and 27. Die Control units 18 and 24 are directly connected to the hydraulic drives 14 flanged.

In FIG. 4, the pump block 19 contains a pump sump 28 and a directly controlled pressure relief valve 29. In FIG. 5 there is one Arrangement supplemented by a pressure accumulator 20, its supply and discharge 30 between the hydraulic pump 19a and the control unit 18 to the Pressure line 31 is connected. A hydroelectric pressure switch 32 limits the pressure in the pressure accumulator 20 and switches via an electrical one Line 33 corresponding to the electric motor of the hydraulic pump 19a. In FIG. 6 there is a hydraulic pump 35 with two in a pump block 34 Rotation and conveying directions are provided.

In the claims and in the description is of at least one Hydraulic drive and an associated control unit. It therefore it is understood that the attachment also other additional equipment and / or can have additional functions, so that also several hydraulic drives with associated control units or directional valves can be provided. In addition, it is understood that in addition for the hydraulic drives also electromechanical drives corresponding control units can be provided, e.g. Rotary drives for rotary devices that are driven purely electrically can and for example electric motors and reduction gears contain.

LIST OF REFERENCE NUMBERS

1

Side shift frame

2

upper horizontal rail

3

lower horizontal rail

4

vertical strut

4a

vertical strut

5

vertical strut

5a

vertical strut

6

notches

7

room

8th

lifting

9

side cheek

10

side cheek

11

stub axle

12

upper horizontal beam

13

lower horizontal beam

14

hydraulic drive

14a

cylinder body

15

piston

16

piston

17

support rollers

18

control unit

18a

magnetic drive

18b

magnetic drive

19

pump block

19a

hydraulic pump

19b

electric motor

20

accumulator

21

capstan

22

hydraulic pump

23

transmission means

24

control unit

25

way valve

26

Pressure relief valve

27

Pressure relief valve

28

sump

29

Pressure relief valve

30

Supply and discharge

31

pressure line

32

hydroelectric pressure switch

33

management

34

pump block

35

hydraulic pump

36

forks

36a

hook

36b

hook

E1

first floor

E2

second level

E1

Third level

Claims (10)

1. Auxiliary device for forklift trucks with a lifting mast, especially for forklift trucks with a lifting sledge (8) affixed to the lifting mast, and two side cheeks (9, 10) as well as two horizontal supports (12, 13) located one above the other at a clear distance ("h"), to which at least one hydraulically operated element of a group consisting of load carrier, transport security element, rotation means, tilting means, pushing means, pulling means, holding means, lifting means, fork adjustment means, or side pushing frame is held together with the relevant associated hydraulic drive, whereby the front sides of the horizontal supports (12, 13) extend across a first vertical plane (E1), and the rear edges of the side cheeks (9, 10) of the lifting sledge (8) extend across a third vertical plane (E3), whereby the said planes (E1, E3) enclose between them a space (7), in which the at least one hydraulic drive (14) is located, which is connected with one of the horizontal supports (12) of the lifting sledge (8), whereby the hydraulic drive (14) is allocated at least one control unit (18, 24), characterised in that apart from the at least one hydraulic drive (14) the relevant associated control unit (18, 24) and at least one drive element out of a group consisting of a hydraulic pump (19,a, 35), a pump motor (19b), a power store, a pump sump (28), a pressure store (20) and radio receiver are also positioned at least in part in the said space (7) between the first (E1) and the third (E3) vertical plane in such a way that the said elements of the hydraulic drive are located behind the first plane (E1).
2. Auxiliary device according to Claim 1, characterised in that the control unit (18, 24) is fixedly connected to the at least one hydraulic drive (14).
3. Auxiliary device according to Claim 1, characterised in that the horizontal support (12) and the cylinder body (14a) of the at least one hydraulic drive (14) are formed from one single piece.
4. Auxiliary device according to Claim 1, characterised in that the arrangement of a side pushing frame (1) for fork prongs incorporates two horizontal rails (2, 3) arranged one above the other on the horizontal supports (12, 13) of the side pushing frame (1), whereby the same are longitudinally and displaceably positioned on the horizontal supports (12, 13) of the lifting sledge (8), and in that the hydraulic drive (14) and the associated control unit (18, 24) for the horizontal displacement of the side pushing frame (1) are located between the planes (E1, E3).
5. Auxiliary device according to Claim 1, characterised in that the hydraulic drive (14) incorporates a double cylinder with equally moveable pistons (15, 16), and in that the control unit (18, 24) consists of a directional valve through which the pressure side of a hydraulic pump (19a, 35) can be switched to one or the other piston (15, 16) depending on the movement direction.
6. Auxiliary device according to Claim 1, characterised in that a pressure store (20) is located within the pressure line (31) between the pressure side of the hydraulic pump (19a, 35) and the control unit (18, 24).
7. Auxiliary device according to Claim 1, characterised in that the pressure side of the hydraulic pump (19a) is switched to a pressure switch (32) with which the hydraulic pump (19a) can be stopped when a predetermined pressure is reached within the pressure store (20).
8. Auxiliary device according to Claim 1, characterised in that the hydraulic drive (14) incorporates a double cylinder with equally moveable pistons (15, 16), and in that the conveying direction of the hydraulic pump (35) is reversible, and in that the control unit (24) incorporates a directional valve (25) and two opposingly switched pressure limiting valves (26, 27).
9. Auxiliary device according to Claim 1, characterised in that the control unit (18, 24) can be activated from the forklift truck via electric cables.
10. Auxiliary device according to Claim 1, characterised in that the control unit (18, 24) can be activated via remote radio control.

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