EP3560885B1 - Industrial truck - Google Patents

Description

The invention relates to an industrial truck with a hitching device for transporting trailers and with a lifting device for lifting loads, the lifting device comprising a fork carriage which is provided with a fork-shaped load-handling device, the load-handling device having at least one load section which extends around a substantially horizontal first pivot axis is arranged on the fork carriage between an unfolded position and a folded position by essentially 90 ° pivotable.

The in-house transport of goods and the flow of materials, in particular the supply of materials to production lines in production facilities, are usually carried out using trailers on which the goods to be transported are transported within the production facility, in particular using pallets.

For pulling one or more of these trailers, industrial trucks designed as tractors are used, which are provided with a corresponding hitch to which one or more trailers can be attached. Such industrial trucks should have compact dimensions in order to be able to safely transport the transport trailer within a production plant on narrow transport routes.

For loading and unloading the trailers, industrial trucks designed as forklifts are used which are provided with a lifting device, for example a lifting mast, on which a fork carriage is arranged so that it can be moved up and down. A load-handling means, for example a load fork consisting of two fork prongs, is arranged on the fork carriage. For the safe transport of a load on the fork tines, such industrial trucks should be provided with a tilting function for the load handling device, with which the tips of the load handling device can be tilted upwards in order to avoid the loss of the load on the load handling device when driving over an irregular roadway to avoid. The tilting function of the load handler must be designed for the maximum load in order to incline the for each load on the load handler To achieve load handling equipment with the tips up. In order to achieve the tilting function of the load-bearing means, it is known to make the lifting mast on which the fork carriage is arranged so that it can be raised and lowered, or to incline the fork carriage in the lifting mast.

In order to be able to implement the functions of pulling trailers and loading and unloading the trailer with a single industrial truck, which combines the function of a compact tractor with the function of a forklift, is from the generic DE 10 2008 036 411 A1 An industrial truck is known which is provided with a hitching device for pulling trailers and in which the fork-shaped load-handling means arranged on a fork carriage which can be raised and lowered in a lifting mast has load sections which can be folded in and out and which are between an unfolded position (function of the Industrial truck as a forklift, for example for loading and unloading the trailer) and a folded position (function of the industrial truck as a compact tractor for pulling trailers) are arranged pivotable by essentially 90 ° on the fork carriage. In this way, an industrial truck is made available in a simple manner, which on the one hand has the function of a tractor, with compact dimensions of the industrial truck being achieved in the longitudinal direction of the vehicle when pulling one or more trailers due to the foldable load sections of the load handling device, and on the other hand has the function of a forklift with which the trailers can be loaded and unloaded.

The folding function of the load sections of the load handling device between the unfolded and the folded position is only possible if there is no load on the load sections. The folding function is therefore only to be designed for the load-free state.

That from the DE 10 2008 036 411 A1 Known industrial truck is not provided with any tilting function of the load handling device in order to enable the load handling device, which has been folded out downwards, to be tilted with a load on it for safe transport.

The present invention is based on the object of providing an industrial truck of the type mentioned at the outset that can be constructed with little construction effort is provided with a folding function of the load sections and a tilting function of the unfolded load sections.

This object is achieved according to the invention in that the fork carriage is arranged on a lifting carriage so that it can pivot about a substantially horizontal second pivot axis, the lifting carriage being arranged so that it can be raised and lowered on the lifting device, and an actuator is provided with which the fork carriage is arranged around the second pivot axis is pivotable relative to the lifting carriage and with which the at least one load section of the load-bearing means can be pivoted about the first pivot axis relative to the fork carriage.

According to the invention, the fork carriage is arranged on the lifting carriage, which can be raised and lowered on the lifting device, so as to be pivotable about a substantially horizontal second pivot axis. In this way, a tilting function of the load sections can be achieved in a simple manner, with which the tips of the downwardly unfolded load sections can be inclined upwards in order to avoid a loss of the load on the load handling device when driving over an irregular roadway. According to the invention, the load sections are furthermore arranged so as to be pivotable about an essentially horizontal first pivot axis on the fork carriage between an unfolded position and a folded position by essentially 90 °. In this way, the folding function of the load sections can be achieved in a simple manner in order to achieve compact dimensions of the industrial truck for transporting trailers in the folded position of the load sections. According to the invention, only a single and thus a common actuator is provided for the folding function and the tilting function of the load sections, so that the two functions (folding function of the load sections and tilting functions of the load sections) can be implemented with little construction effort.

The industrial truck according to the invention has the function of a tractor for pulling trailers with the load sections folded up. With the load sections folded upwards, the industrial truck can be made small in the longitudinal direction of the vehicle in order to achieve agile maneuvering in narrow aisles. The trailer device to which the trailer is coupled is preferably arranged on the fork carriage and thus on the rear of the vehicle. The industrial truck according to the invention points downwards The unfolded load sections continue to function as a forklift truck for loading and unloading the trailer and for transporting loads on the unfolded load sections. With the tilting function of the fork carriage and thus the tilting function of the load sections arranged on the fork carriage, it is possible to incline the tips of the load sections upwards, so that a loss of the load on the load sections when driving, especially at high speeds, over an irregular roadway can be safely avoided. In the industrial truck according to the invention, the load is normally located in the rear of the truck when it is being transported, so that a driver of the truck does not see the load while the truck is traveling. With the tilting function of the fork carrier and thus the tilting function of the load sections arranged on the fork carrier, the risk of losing the load located on the unfolded load sections is reliably avoided.

The tilting function of the fork carriage and the load sections is preferably a pivoting movement of the fork carriage about the second pivot axis through an angle of 10 ° or less. The tilting function of the fork carriage and the load sections must be available for each load weight of a load transported on the load sections (from 0 kg to the maximum load / payload of the industrial truck).

The folding function of the load sections is preferably a pivoting movement of the load sections about the first pivot axis by approximately 90 °. Since the load sections are almost in a vertical position in the upwardly folded position, the folding function of the load sections only has to be available if there is no load on the load sections, as in the event that there is a load on the load sections , the folding process of the load sections upwards cannot be completed.

The combination of the two different functions of the load sections (folding function and tilting function of the load sections) is technically complex since the two functions require different levels of force. According to the invention, the two functions of the load sections (folding function and tilting function of the load sections) do not require two different actuators, namely a first actuator for the folding function and a second actuator for the tilting function, but a single, common actuator for both Folding function as well as for the tilting function intended. This leads to advantages, since this results in a simple structure with little construction effort, as well as simple control, since only one actuator has to be supplied with energy, whereby the construction effort can be further reduced.

According to a preferred embodiment of the invention, the actuator is formed by a linear drive which swivels the fork carriage around the second pivot axis relative to the lifting carriage in a first adjustment range and pivots the at least one load section of the load-bearing device around the first pivot axis relative to the fork carriage in a second adjustment range. With a linear drive, which in the first adjustment range pivots the fork carriage about the second pivot axis relative to the lifting carriage and thus enables the tilting function of the load sections and which in a second adjustment range pivots the at least one load section of the load handling device around the first pivot axis relative to the fork carriage and thus the folding function the load section achieved, the two functions (tilting function and folding function) and the two different movements (pivoting fork carriage for tilting function / pivoting load sections for folding function) can be achieved in a simple manner and with little construction effort.

According to a preferred embodiment of the invention, the actuator is formed by a hydraulic cylinder which is fastened to the lifting carriage with a cylinder housing and has an extendable piston rod which swivels the fork carriage about the second pivot axis relative to the lifting carriage in a first stroke area and which swivels in a second stroke area at least one load section of the load suspension device is pivoted about the first pivot axis relative to the fork carriage. The two functions (tilting function and folding function) and the two different movements (pivoting fork carriage for tilting function / pivoting load sections for folding function) can thus be achieved in a simple manner and with little construction effort using a single hydraulic cylinder.

With particular advantage, at least one first contact body is arranged on the piston rod, which is in operative connection with a vertical contact surface of the lifting carriage, and at least one second contact body is arranged, which is in operative connection with a contact surface of the fork carrier inclined with respect to the vertical. With such contact bodies, which are in operative connection with a vertical contact surface of the lifting carriage and with a contact surface of the fork carriage inclined relative to the vertical, a pivoting movement of the fork carriage on the lifting carriage around the second pivot axis can be achieved in a simple manner in the first stroke area in order to adjust the tilting function of the To achieve fork carrier and thus the load sections arranged on the fork carrier.

The vertical contact surface of the lifting slide preferably extends over the first stroke area and the second stroke area of the piston rod and the inclined contact surface of the fork carrier extends over the first stroke area of the piston rod. This ensures that the fork carriage is pivoted only in the first stroke area and the piston rod can be supported on the vertical contact surface of the lifting carriage both in the first stroke area and in the second stroke area via the first contact body.

At least one third contact body is preferably arranged on the piston rod, which in the second stroke area of the piston rod comes into operative connection with an actuating device with which the at least one load section of the load handling device can be pivoted about the first pivot axis relative to the fork carriage. With such a contact body, which comes into operative connection in the second stroke area with the actuating device, which pivots the load sections about the first pivot axis, a pivoting movement of the load sections on the fork carriage about the first pivot axis can be achieved in a simple manner in the second stroke area of the piston rod to achieve the folding function of the load sections.

According to an advantageous embodiment of the invention, the actuating device has a first actuating lever which is arranged in an articulated manner on the fork carriage and on which at least one load section of the load suspension device is supported. With such an actuating lever, which is actuated directly or indirectly by the piston rod, the load sections can be pivoted about the first pivot axis in a simple manner.

The actuating device can only have the first actuating lever, which comes into direct operative connection with the piston rod in the second stroke area and is actuated directly by the piston rod.

According to an advantageous development of the invention, the actuation device has a second actuation lever which is articulated on the first actuation lever and which is provided with a receptacle for the third contact body. The first operating lever is thus operated indirectly by the piston rod. The use of a second operating lever, which comes into operative connection with the piston rod in the second stroke area and which transfers the forces of the piston rod to the first operating lever, enables the load sections to be folded in and out with low forces.

A second contact body is preferably arranged on the piston rod between two first contact bodies and two third contact bodies are provided, between which the two first contact bodies and the second contact body are arranged. A total of five contact bodies are thus arranged on the piston rod. This makes it possible to arrange the second contact body on the longitudinal axis of the piston rod and to arrange the two first contact bodies and the two third contact bodies symmetrically to the longitudinal axis of the piston rod, which has a favorable effect on the distribution of forces on the piston rod.

According to an advantageous embodiment of the invention, the contact bodies are designed as rollers rotatably arranged on the piston rod. As a result, during the tilting function and during the folding function, there is no sliding friction but rolling friction on the contact bodies, whereby wear and tear can be minimized.

According to a preferred embodiment of the invention, the first stroke area of the piston rod is larger than the second stroke area of the piston rod. This enables a favorable design of the forces required and the energy required for the tilting function and the folding function. As a rule, only low to medium pressures of the hydraulic cylinder are required for the folding function, since the folding function, which is 90 °, only has to be carried out without a load, usually in the range of 5% of the payload. Since the tilting function of the fork carriage, which is usually is only 3 ° -10 ° and must be available for the maximum load / payload, thus extending over a wide stroke range of the piston rod, the tilting function can also be implemented with low to medium pressures in the hydraulic cylinder.

According to one embodiment of the invention, it is particularly advantageous if an end stop is provided between the lifting carriage and the fork carriage which limits the pivoting movement of the fork carriage relative to the lifting carriage. With such an end stop, the tilting function with raised tips of the load sections can be limited in a simple manner to a desired value, for example 3 ° -5 °.

The end stop is advantageously formed by an elastic element which is connected to the fork carriage and interacts with a stop surface of the lifting carriage. With an elastic element as an end stop, the pivoting movement of the fork carriage and thus the tilting function can be stopped gently. If the towing device is arranged on the fork carriage, the elastic element can also be used to reduce the vibrations and shocks coming from the towing device when the trailer is being pulled during acceleration and braking when the truck is trailered with one or more trailers attached.

The elastic element is preferably designed as a sleeve which is arranged on a fastening rod fastened to the fork carriage. As a result, the end stop can be implemented in a simple manner and with little construction effort.

The second operating lever is preferably designed as a push rod.

If, according to an advantageous embodiment of the invention, the second operating lever on the receptacle for the third contact body is provided with an insertion bevel for the third contact body, a guide for the third contact body can be achieved in a secure manner with the insertion bevels, so that the third contact body during the stroke the piston rod is guided into the receptacle for an optimal fit.

The second operating lever is advantageously urged into an initial position by a spring. The spring makes it possible to hold the actuating lever securely in a defined starting position when it does not interact with the third contact body, so that it is ensured that the third contact body can hit the receptacle on the second actuating lever when the piston rod is extended.

A sensor device is particularly advantageously provided with which the pivoting movement of the at least one load section of the load-bearing means about the first pivot axis relative to the fork carriage can be detected. With such a sensor device, the folding function can be safely monitored and the folded-in position and the folded-out position of the load sections can be detected in order to achieve a high level of operational safety for the industrial truck.

The at least one load section of the load-bearing means is preferably supported in the unfolded position on a support surface of the fork carrier. This reliably prevents the load sections from being able to pivot about the first pivot axis below the unfolded position and a secure and stable support of the load on the unfolded load sections on the fork carriage is achieved.

According to an advantageous embodiment of the invention, the at least one load section of the load handling device can come into contact with a stop on a vehicle body of the industrial truck in the folded position. This prevents the lifting carriage from being lifted when the load sections are in the upwardly folded position. As a result, safe trailer operation can be achieved.

The trailer hitch is preferably arranged on the fork carriage.

According to an advantageous embodiment of the invention, a hydraulic lifting cylinder is provided for raising and lowering the lifting carriage, to which a pressure limiting valve is assigned to limit a maximum load to be lifted. With a pressure relief valve of this type, lifting a load that is too heavy can be avoided in a simple manner.

According to an advantageous embodiment of the invention, the hydraulic cylinder is designed as a double-acting hydraulic cylinder to which a further pressure limiting valve is assigned. With a further pressure relief valve of this type, the tilting function and the folding function of the load sections can be secured in a simple manner and an excessively heavy load can be prevented from being tilted with the tilting function and / or the folding function being carried out when there is a load on the load sections.

Figur 1

eine erfindungsgemäßes Flurförderzeug in einer perspektivischen Darstellung auf das Fahrzeugheck mit nach unten ausgeklappten Lastabschnitten,

Figur 2

das Flurförderzeug der Figur 1 mit nach oben eingeklappten Lastabschnitten,

Figur 3

einen Ausschnitt der Figur 1 mit durch die Neigefunktion waagerecht angeordneten Lastabschnitten,

Figur 4

die Figur 3 in einer Seitenansicht,

Figur 5

eine Darstellung gemäß der Figur 4 mit durch die Neigefunktion nach oben geneigten Lastabschnitten,

Figur 6

eine Darstellung gemäß der Figur 4 mit durch die Klappfunktion nach oben eingeklappten Lastabschnitten,

Figur 7

einen Schnitt der Figur 4 mit durch die Neigefunktion waagerecht angeordneten Lastabschnitten,

Figur 8

einen Schnitt der Figur 5 mit durch die Neigefunktion nach oben geneigten Lastabschnitten,

Figuren 9a bis 9c

Schnittdarstellungen gemäß den Figuren 7 und 8 mit einer Verdeutlichung des Aufbaus und Ablauf der Klappfunktion der Lastabschnitte,

Figur 10

eine Ansicht gemäß Pfeil A in der Figur 3,

Figur 11

einen als Hydraulikzylinder ausgebildeten Stellantrieb,

Figur 12

den Hydraulikzylinder der Figur 11 in verschiedenen Hubstellungen,

Figur 13

einen Ausschnitt der Figur 9b in einer perspektivischen Darstellung,

Figuren 14a-14c

Schnittdarstellungen gemäß der Linie B-B der Figur 10 mit unterschiedlichen Stellungen des Gabelträgers und der Lastabschnitte,

Figur 15

einen Ausschnitt der Figur 6 in einer vergrößerten Darstellung,

Figur 16

den zweiten Betätigungshebel in einer Seitenansicht,

Figur 17

einen Ausschnitt der Figur 3 mit einer Verdeutlichung des Aufbaus der Sensoreinrichtung,

Figur 18

einen Ausschnitt der Figur 2 mit einer Verdeutlichung des Aufbaus des Anschlags an dem Fahrzeugkörper des Flurförderzeugs und

Figur 19

den Schaltplan einer Hydraulikanlage des erfindungsgemäßen Flurförderzeugs.

Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiment shown in the schematic figures. Here shows

Figure 1

an industrial truck according to the invention in a perspective view of the rear of the vehicle with load sections folded out downwards,

Figure 2

the truck of the Figure 1 with load sections folded up,

Figure 3

a section of the Figure 1 with horizontally arranged load sections due to the tilt function,

Figure 4

the Figure 3 in a side view,

Figure 5

a representation according to Figure 4 with load sections inclined upwards due to the tilting function,

Figure 6

a representation according to Figure 4 with load sections folded up using the folding function,

Figure 7

a cut of the Figure 4 with horizontally arranged load sections due to the tilt function,

Figure 8

a cut of the Figure 5 with load sections inclined upwards due to the tilting function,

Figures 9a to 9c

Sectional representations according to Figures 7 and 8 with an illustration of the structure and sequence of the folding function of the load sections,

Figure 10

a view according to arrow A in FIG Figure 3 ,

Figure 11

an actuator designed as a hydraulic cylinder,

Figure 12

the hydraulic cylinder of the Figure 11 in different stroke positions,

Figure 13

a section of the Figure 9b in a perspective view,

Figures 14a-14c

Sectional views along the line BB of Figure 10 with different positions of the fork carriage and the load sections,

Figure 15

a section of the Figure 6 in an enlarged view,

Figure 16

the second operating lever in a side view,

Figure 17

a section of the Figure 3 with an illustration of the structure of the sensor device,

Figure 18

a section of the Figure 2 with an illustration of the structure of the stop on the vehicle body of the industrial truck and

Figure 19

the circuit diagram of a hydraulic system of the industrial truck according to the invention.

In the Figures 1 and 2 an inventive industrial truck 1 is shown in a perspective view, which can be used as a tractor and as a counterbalanced forklift.

The industrial truck 1, viewed in the longitudinal direction of the vehicle, has a front drive part 2 in which at least one steerable drive wheel, not shown in detail, is arranged. The industrial truck 1 according to the invention has an electric drive system and comprises an electric travel drive motor and steering motor, which are arranged in the drive part 2 and are no longer shown, and are in operative connection with the drive wheel. In the drive part 2 or adjacent to the drive part 2, a battery compartment 3 is arranged, in which an energy supply device of the electric drive system can be arranged, for example a battery block.

Following the drive part 2 and the battery compartment 3, the industrial truck 1 has a driver's workstation 4 which is formed by a standing platform 5. A rear frame section 6, which is provided with load rollers 7, is formed adjacent to the driver's seat 4.

To operate the industrial truck 1, a handlebar-like operating arrangement 8 is provided, which is arranged on the upper side of the drive part 2.

The industrial truck 1 according to the invention is provided with a lifting device 9 on the rear frame section 6 or adjacent to the rear frame section 6. The lifting device 9 is designed as a lifting frame with a fixed, non-inclinable standing mast 10, which has two standing mast profiles 10a, 10b which are spaced apart in the transverse direction of the vehicle and which are arranged vertically and which are fastened to the rear frame section 6, for example. In the standing mast profiles 10a, 10b, a lifting carriage 11 is arranged so that it can be moved up and down by means of guide rollers not shown in detail. To raise and lower the lifting slide 11, a lifting drive 12, designed as a lifting cylinder 12a, for example, is provided, which is connected to the lifting slide 11 by means of a lifting means, for example a lifting chain.

A fork carriage 13 of the lifting device 9 is arranged on the lifting carriage 11. The fork carriage 13 is provided with a fork-shaped load-receiving means 14 which, in the exemplary embodiment shown, is formed by two load sections 14a, 14b arranged laterally in the transverse direction of the vehicle. The two Load sections 14a, 14b are arranged around an essentially horizontal first pivot axis D1 arranged in the transverse direction of the vehicle on the fork carriage 13 between a downwardly unfolded position ( Figure 1 ) and a folded-up position ( Figure 2 ) arranged pivotable by essentially 90 °.

A hitching device 20 for transporting trailers is also provided on the fork carriage 13. The towing device 20 here has several vertically spaced flange plates in which a coupling bolt can be arranged. The towing device 20 can be actuated manually or be designed as an automatic coupling device which can be actuated from the driver's seat by means of a corresponding actuating element.

In the Figure 1 , in which the load sections 14a, 14b are folded out downwards, the industrial truck 1 has the function of a forklift, with which loads can be handled and transported on the load sections 14a, 14b. In the function of a forklift truck, a tilting function is desired for the load sections 14a, 14b, with which the load sections 14a, 14b can be tilted with the tips upwards in order to avoid a loss of the load on the load sections 14a, 14b while driving, in particular with Avoid high driving speeds over an irregular roadway. In the case of the industrial truck 1 according to the invention, the load on the load sections 14a, 14b is normally located in the rear of the truck 1 when it is being transported, so that a driver of the industrial truck 1 who is in the driver's workplace 4 and who is looking forward in the direction of travel towards the handlebars 10 does not see the load in his back while driving the truck 1. With the tilting function of the load sections 14a, 14b arranged on the fork carriage 13, the risk of losing the load located on the unfolded load sections 14a, 14b is reliably avoided.

In the Figure 2 , in which the load sections 14a, 14b are folded up, the industrial truck 1 has the function of a tractor which is compact in the longitudinal direction of the vehicle and to which trailers can be attached to the trailer device 20 and pulled.

In the industrial truck 1 according to the invention, the fork carriage 13 arranged on the lifting carriage 11 has a tilting function with which the tips of the load sections 14a, 14b can be tilted upwards (tilting back). In addition, the load sections 14a, 14b are provided with the folding function and can be switched between the downward unfolded position ( Figure 1 ) and the folded up position ( Figure 2 ) can be folded in and unfolded.

The structure of the lifting carriage 11 with the fork carriage 13 and the load sections 14a, 14b with the tilting function and the folding function is illustrated below with reference to FIG Figures 3 to 18 described in more detail.

The fork carriage 13 is arranged on the lifting carriage 11 so as to be pivotable about a substantially horizontal second pivot axis D2 arranged in the transverse direction of the vehicle. The second pivot axis D2 is arranged in the upper area of the lifting carriage 11 and of the fork carrier 13.

An actuator 25 is provided with which the fork carriage 13 can be pivoted about the second pivot axis D2 relative to the lifting carriage 11 and with which the at least one load section 14a, 14b of the load-bearing means 14 can be pivoted about the first pivot axis D1 relative to the fork carriage 13.

The actuator 25 is formed by a linear drive designed as a hydraulic cylinder 26, which - as from the Figures 7 to 10 can be seen - is attached to a cylinder housing 26a on the lifting carriage 11 and which has an extendable piston rod 26b which - like the Figure 12 - in a first lifting area H1 the fork carriage 13 is pivoted about the second pivot axis D2 relative to the lifting carriage 11 and in a second lifting area H2 adjoining the first lifting area H1 the at least one load section 14a, 14b of the load handling device 14 about the first pivot axis D1 relative to Fork carriage 13 pivoted.

To actuate the fork carrier 13 and the load sections 14a, 14b, a plurality of contact bodies are arranged on the piston rod 26b, as in FIG Figure 11 is shown in more detail.

At least one first contact body 30a, 30b is arranged on the piston rod 26b and is in operative connection with a vertical contact surface 31a, 31b of the lifting carriage 11, and at least one second contact body 32 is arranged with a contact surface 33 of the fork carrier that is inclined with respect to the vertical V 13 is in operative connection. A contact surface 36 of the fork carrier 13 adjoins the inclined contact surface 33. The contact surface 33 is thus inclined with respect to the contact surface 31a, 31b. The contact surface 31a, 31b is arranged on a front side of the lifting carriage 11 facing the fork carriage 13 and the inclined contact surface 33 and the adjoining contact surface 36 are arranged on a rear side of the fork carriage 13 facing the lifting carriage 11.

The vertical contact surface 31a, 31b of the lifting carriage 11 extends over the first stroke area H1 and the second stroke area H2 and thus over the entire stroke of the piston rod 26b. The inclined contact surface 33 of the fork carrier 13 extends only over the first stroke area H1 of the piston rod 26b.

At least one third contact body 34a, 34b is arranged on the piston rod 26b, which in the second stroke area H2 of the piston rod 26b comes into operative connection with an actuating device 40 with which the at least one load section 14a, 14b of the load-bearing means 14 about the first pivot axis D1 relative to the fork carriage 13 is pivotable.

In the illustrated embodiment are on the piston rod 26b - as from the Figure 11 can be seen - a total of five contact bodies 30a, 30b, 32, 34a, 34b are arranged. The second contact body 32 is arranged on the longitudinal axis LA of the hydraulic cylinder 26. The second contact body 32 is attached between two first contact bodies 30a, 30b, which are arranged on both outer sides of the contact body 32. Furthermore, two third contact bodies 34a, 34b are provided, between which the two first contact bodies 30a, 30b are arranged. The contact body 34a is arranged on the outside of the contact body 30a and the contact body 34b is arranged on the outside of the contact body 30b.

The contact bodies 30a, 30b, 32, 34a, 34b are designed as rollers that are rotatably arranged on the piston rod 26b. For the rotatable mounting of the rollers designed as rollers Contact body 30a, 30b, 32, 34a, 34b, a fork-shaped holder 35 is arranged on the piston rod 26b, in which the rollers are rotatably mounted.

The first contact bodies 30a, 30b designed as rollers are only in contact with the vertical contact surface 31a, 31b of the lifting carriage 11. The first contact bodies 30a, 30b designed as rollers run on the contact surface 31a, 31b in the first stroke area H1 and the second stroke area H2. The second contact body 32, designed as a roller, is only in contact with the inclined contact surface 33 and the contact surface 36 of the fork carrier 13 adjoining the inclined contact surface 33. The second contact body 32, designed as a roller, runs in the first stroke area H1 on the inclined contact surface 33 and in the second stroke area on the contact surface 36. The third contact bodies 34a, 34b, which are designed as rollers, only come into contact with the actuating device 40 in order to Lifting range H2 to pivot the load sections 14a, 14b about the first pivot axis D1.

The actuating device 40 has - as in Figures 3 to 10 and 13 is shown in more detail - a first operating lever 41, which is articulated on the fork carriage 13 on a hinge axis G1. The first actuation lever 41 is also supported on the at least one load section 14a, 14b of the load suspension means 14. The two load sections 14a, 14b are connected by means of a cross strut 14c ( Figure 10 ) connected, on which the operating lever 41 is supported. For this purpose, a contact body 120 can be provided on the first actuation lever 14 so that it can rotate about a second hinge axis G2 on the first actuation lever 41 and is designed as a roller. The contact body 120 is supported, for example, on the transverse strut 14c and rolls on this when the load sections 14a, 14b of the load suspension means 14 are pivoted about the first pivot axis D1. The actuating lever 41 of the actuating device 40 is thus in contact with the cross strut 14c in the area of the second joint axis G2 by means of the contact body 120 designed as a roller. When the load sections 14a, 14b of the load suspension device 14 are folded up and down about the first pivot axis D1, the contact point between the actuating lever 41 and the cross strut 14c changes, for which the contact body 120, designed as a roller, rolls along the cross strut 14c.

The actuation device 40 has a pair of second actuation levers 42a, 42b which are articulated on the first actuation lever 41 about a hinge axis G3.

The operating lever 42a is - as from the Figures 15 and 16 can be seen in more detail - provided with a receptacle 43a for the third contact body 34a. Correspondingly, the actuating lever 42b is provided with a receptacle 43b for the third contact body 34b.

The first actuating lever 41 thus actuates the two load sections 14a, 14b by means of the contact body 120 designed as a roller and the second actuating levers 42a, 42b are provided in order to transmit the forces from the piston rod 26b of the hydraulic cylinder 26 to the first actuating lever 41. The second operating lever 42a, 42b is designed as a push rod which only transmits compressive forces F from the contact body 34a, 34b to the first operating lever 41, as in FIG Figure 15 is illustrated.

On the receptacle 43a, 43b, the second actuating lever 42a, 42b is provided with an insertion bevel 44 which forms a guide to guide the third contact body 34a, 34b in the first stroke area H1 in order to ensure a perfect fit of the contact body at the end of the first stroke area H1 34a, 34b in the receptacle 43a, 43b.

The second operating lever 42a, 42b is each supported by a spring 45 ( Figure 15 ) is acted upon in an initial position, which in the Figure 7 and 10 is shown. The spring 45 is fastened with a first end to the actuating lever 42a or 42b and with a second end to the fork carriage 13. In the illustrated embodiment, the spring 45 is designed as a tension spring.

An end stop 50 is provided between the lifting carriage 11 and the fork carriage 13, which limits the pivoting movement of the fork carriage 13 relative to the lifting carriage 11 and thus the tilting movement of the tilting function. The structure of the end stop 50 is based on Figures 10 , 13, 14a-14c described in more detail. The end stop 50 is formed by an elastic element 51 which is connected to the fork carrier 13 and interacts with a stop surface 52 of the lifting carriage 11.

In the exemplary embodiment shown, the elastic element 51 is designed as a sleeve 51 a, for example a rubber sleeve, which is arranged in a longitudinally displaceable manner on a fastening rod 53 fastened to the fork carrier 13. The fastening rod 53 extends through a hole in the lifting slide 11 onto the rear side of the lifting slide 11 opposite the fork carriage 13, on which the stop surface 52 is formed. The elastic element 51 is arranged between the stop surface 52 on the lifting carriage 11 and a holder 54 arranged on the fastening rod 53. In the exemplary embodiment shown, the holder 54 is formed by a nut screwed onto the fastening rod 53 and a washer which is arranged between the element 51 and the nut.

Furthermore, a sensor device 70 is provided with which the pivoting movement of the at least one load section 14a, 14b of the load-bearing means 14 about the first pivot axis D1 relative to the fork carriage 13 can be detected. The sensor device 70 consists in the illustrated embodiment - as from the Figures 10 and 14th can be seen in more detail - from a sensor 71 arranged on the fork carriage 13, for example a non-contact inductive sensor, and measuring elements 72 arranged on the load section 14a, for example finger-like extensions that move into the measuring field of the when the load section 14a is pivoted about the first pivot axis D1 Move sensor 71. The sensor device 70 is connected to an electronic control device of the industrial truck 1.

The at least one load section 14a, 14b of the load handling device 14 is supported in the downwardly folded-out position on a support surface 75 of the fork carriage 13 ( Figure 18 ). For this purpose, the load sections 14a, 14b are each provided with a stop 76 which, in the downwardly unfolded position, rests against the support surface 75 of the fork carrier 13 and thus prevents the load sections 14a, 14b from pivoting further downwards. If, in the downwardly unfolded position, there is a load on the load sections 14a, 14b, the weight of the load is supported on the fork carriage 13 via the stop 76 and the support surface 75.

At least one of the two load sections 14a, 14b of the load handling device 14 can come into contact with a stop 80 on a vehicle body of the industrial truck 1 in the upwardly folded position. For this purpose, the load sections 14a, 14b are each provided with a projection 81, which can come into contact with the stop 80 when the load sections 14a, 14b are in the upwardly folded position. When the projection 81 rests against the stop 80, unintentional lifting of the lifting carriage 11 in the stationary mast 10 can be avoided, for example in the pulling mode when pulling a trailer attached to the towing device 20.

In the Figures 3-5 , 7th , 8th and 9a the configuration of the industrial truck 1 according to the invention is shown as a counterbalanced forklift. The load sections 14a, 14b are in the downwardly folded-out position with the folding function. In the Figures 3, 4 and 7th the load sections 14a, 14b are in a horizontal position due to the tilting function with a minimum tilting angle of 0 °, for example. The piston rod 26b of the hydraulic cylinder 26 is completely retracted. In the Figures 5 , 8th and 9a the load sections 14a, 14b are in a position inclined by the inclination function with raised tips with a maximum inclination angle of, for example, 3 ° -5 ° (back inclination). The piston rod 26b of the hydraulic cylinder 26 is extended to the end of the first stroke range H1.

In the Figures 6 and 9c the configuration of the industrial truck 1 according to the invention is shown as a tractor. The load sections 14a, 14b are in the position folded upwards with the folding function. The piston rod 26b of the hydraulic cylinder 26 is extended to the end of the second stroke range H2.

In the case of the industrial truck 1 according to the invention, the lifting carriage 11 in the stationary mast 10 can be raised and lowered by means of the lifting drive 12. On the lifting carriage 11, the fork carriage 13 is arranged to be pivotable about the second axis of rotation D2 in order to use the hydraulic cylinder 26 to perform the tilting function of the downwardly unfolded load sections 14a, 14b for safe transport of an on the To enable load sections 14a, 14b located load in the configuration of the industrial truck 1 as a counterbalanced forklift. The rotational movement of the fork carrier 13 about the second pivot axis D2 forms the tilting function and the tilting movement of the load sections 14a, 14b. The load sections 14a, 14b are arranged on the fork carriage 13 so that they can be folded in and out about the first pivot axis D1 in order to achieve the folding function of the load sections 14a, 14b with the hydraulic cylinder 26 in order to configure the truck 1 with the load sections 14a, 14b folded down as a counterbalanced forklift and with the load sections 14a, 14b folded upwards, the configuration of the industrial truck 1 as a tractor. In the downwardly unfolded position, the load sections 14a, 14b rest with the stop 76 on the support surface 75 of the fork carrier 13 and cannot pivot further downward about the first pivot axis D1.

Is based on the Figures 3, 4 and 7th When the piston rod 26b of the hydraulic cylinder 26 is extended downwards, the contact bodies 30a, 30b arranged on the piston rod 26b run down on the contact surfaces 31a, 31b of the lifting carriage 11 and the contact body 32 arranged on the piston rod 26b runs on the inclined contact surface 33 of the fork carrier 13 downward. This causes the fork carrier 13 to pivot about the second pivot axis D2 relative to the lifting carriage 11 and the tilting function of the load sections 14a, 14b is achieved. The inclined contact surface 33 of the fork carrier 13 extends over the first lifting area H1 of the lifting cylinder 26, so that in the first lifting area H1 of the hydraulic cylinder 26, only the tilting function of the load sections 14a, 14b is achieved with the rotary movement of the fork carrier 13 relative to the lifting carriage 11.

During the extension movement of the piston rod 26b in the first stroke range H1 of the hydraulic cylinder 26, the bevels 44 on the actuating lever 42a, 42b guide the contact bodies 34a, 34b arranged on the piston rod 26b into the receptacle 43a, 43b of the actuating levers 42a, 42b, so that at the end of the first stroke area H1, the contact bodies 34a, 34b run into the receptacles 43a, 43b of the actuating levers 42a, 42b.

The Figures 5 , 8th and 9a show the position at the end of the first stroke range H1 of the piston rod 26b, in which the load sections 14a, 14b with the tilting function are inclined maximally upwards.

Is based on the Figures 5 , 8th and 9a If the piston rod 26b of the hydraulic cylinder 26 is extended further down into the stroke area H2, the contact bodies 30a, 30b arranged on the piston rod 26b run down on the contact surfaces 31a, 31b of the lifting carriage 11 and the contact body 32 arranged on the piston rod 26b runs on the contact surface 36 of the fork carriage 13 down. The contact surface 36 is arranged parallel to the contact surface 31a, 31b so that the extension movement of the piston rod 36b in the second stroke area H2 does not lead to any further pivoting of the fork carriage 13 about the second pivot axis D2 relative to the lifting carriage 11. Is based on the Figures 5 , 8th and 9a With the piston rod 26b of the hydraulic cylinder 26 extended further down into the stroke range H2, the contact bodies 34a, 34b on the piston rod 26b, which are arranged in the receptacles 43a, 43b of the second actuating levers 42a, 42b, actuate the first actuating lever 41, so that the load sections 14a, 14b be pivoted upwards around the first pivot axis D1 on the fork carriage 13 and folded in ( Figure 9b ). At the end of the second stroke range H2, the load sections 14a, 14b are fully folded up ( Figures 6 , and 9c ). In the second stroke area H2 of the hydraulic cylinder 26, the contact of the contact bodies 34a, 34b with the actuating levers 42a, 42b, which transmit the extension movement of the piston rod 26b of the hydraulic cylinder 26 to the load sections 14a, 14b, exclusively performs the folding function of the load sections 14a, 14b achieved with the rotary movement of the load sections 14a, 14b relative to the fork carrier 13.

As from the Figures 14a-14c can be seen, the position of the Figure 14a the Figure 7 corresponds to the position of Figure 14b the Figure 8 corresponds and the position of Figure 14c the Figure 9c corresponds, at the end of the first stroke range H1, the elastic element 51 arranged on the actuating rod 53 comes into contact with the stop surface 52 and limits the tilting function of the fork carrier 13 and thus of the load sections 14a, 14b to the desired value of, for example, 3 ° to 5 °. The elastic element 51 leads to a gentle stop of the tilting movement of the fork carrier 13 ( Figure 14b ). Since when the load sections 14a, 14b ( Figure 14c ) the fork carriage 13 in the same position as in the Figure 14b is and thus the elastic element 51 is in contact with the stop surface 52, the elastic element 51 can continue to reduce vibrations and shocks when pulling a trailer attached to the trailer hitch 20, which are caused by the hitch 20 in the pulling mode of a trailer when accelerating and Come slow down.

With the contact bodies 30a, 30b, 32, 34a, 34b designed as rollers, sliding friction is avoided and rolling friction is achieved both during the tilting function and during the folding function, whereby wear is minimized. With the contact body 120 designed as a roller, sliding friction at the contact point between the actuating lever 41 and cross strut 14c is also avoided and rolling friction is achieved during the folding function of the load sections 14a, 14b, whereby wear is minimized. Furthermore, the actuating levers 41, 42a, 42b are preferably mounted accordingly in order to achieve low friction and low wear.

The first lifting range H1, in which the tilting function of the load sections 14a, 14b is achieved, which must be available for the maximum load / payload on the load sections 14a, 14b and which leads to an inclination of the load by 5 °, for example, preferably extends Over a stroke range from 0% to approx. 70% of the stroke of the piston rod 26b of the hydraulic cylinder 26. The second stroke range H2, in which the folding function of the load sections 14a, 14b by 90 ° is achieved, which is only available for unloaded load sections 14a, 14b must stand, whereby the moving mass of the load sections 14a, 14b to be folded is usually about 5% of the payload, preferably extends over a stroke range of about 70% to 100% of the stroke of the piston rod 26b of the hydraulic cylinder 26. The first stroke range H1 of the Piston rod 26b is therefore preferably larger than the second stroke area H2 of piston rod 26b.

The ratio between the piston stroke of the piston rod 26b, moving mass, required tilting movement and folding movement of the load sections 14a, 14b can thus be optimized in such a way that low pressures of the hydraulic cylinder 26 for the tilting function without load, medium pressures of the hydraulic cylinder 26 for the folding function and high pressures of the Hydraulic cylinder 26 are required for the tilting function with a load. Secure the pressure of the hydraulic cylinder 26 with a The pressure limiting valve or a pressure sensor that detects the pressure of the hydraulic cylinder 26 can therefore be used to easily detect and avoid incorrect operations, for example avoiding the tilting function with an impermissibly high load on the load sections 14a, 14b or avoiding the folding function with a load on the load sections 14a, 14b will.

In the Figure 19 the circuit diagram of a hydraulic system of the industrial truck 1 according to the invention is shown.

A hydraulic pump 100 delivers into a delivery line 101. The lifting cylinder 12a is designed as a single-acting hydraulic cylinder which is connected to the delivery line 101 by means of a line 102. In the line 102 a valve 103 is arranged, with which the lifting and lowering operation of the lifting cylinder 12a can be controlled. A drain line 106, which leads to a container 105 and in which a drain valve 104 is arranged, branches off from the delivery line 101.

A pressure limiting valve 107 is connected to the delivery line 101, which limits the maximum delivery pressure in the delivery line 101 and serves to limit a maximum load to be lifted with the lifting cylinder 12a. The pressure limiting valve 107 can thus prevent an inadmissibly high load from being lifted with the lifting cylinder 12a.

The hydraulic cylinder 26 for the tilting function and the folding function is designed as a double-acting hydraulic cylinder. A directional control valve 110, which is connected to the delivery line 101, is provided for controlling the retraction movement and the extension movement of the piston rod 26b. A line 111a is connected to the directional control valve 110, which is connected to the pressure chamber of the hydraulic cylinder 26 acting in the direction of the extension movement of the piston rod 26b, and a line 111b is connected to the pressure chamber of the hydraulic cylinder 26 acting in the direction of the retraction movement of the piston rod 26b is. A further pressure limiting valve 112 is connected to the line 111a and limits the maximum actuation pressure in the line 111a. With the pressure relief valve 112, the tilting function with an impermissibly high load on the load sections 14a, 14b and / or the folding function with a load on the load sections 14a, 14b can be prevented.

In line 111a there is also a shut-off valve 113 which can be opened into an open position by the pressure in line 111b. To bypass the shut-off valve 113, a bypass line 114 is provided in which a check valve 115 opening in the direction of the pressure chamber of the hydraulic cylinder 26 is arranged. With the shut-off valve 113, undesired movement and undesired acceleration of the piston rod 26b due to external forces can be avoided.

The invention is not limited to the illustrated embodiment.

Instead of the actuating levers 41, 42a, 42b, the actuating device can have only a single actuating lever.

Instead of the actuator being designed as a hydraulic cylinder 26, the actuator can be designed as an electric linear drive.

The inclination function can also incline the fork tips of the load sections 14a, 14b in relation to the representation of the Figure 4 include downward and thus a forward leaning of the load sections 14a, 14b.

Other values can also be selected for the stroke ranges H1 and H2, for example the first stroke range H1, in which the tilting function is achieved, can extend over a stroke range from 0% to approx. 50% of the stroke of the piston rod 26b of the hydraulic cylinder 26 and the The second stroke area H2, in which the folding function is achieved, extend over a stroke area of approximately 50% to 100% of the stroke of the piston rod 26b of the hydraulic cylinder 26.

Claims (23)

1. Industrial truck (1) having a hitch (20) for transporting trailers and having a lifting device (9) for lifting loads, wherein the lifting device (9) comprises a fork carrier (13) which is equipped with a fork-shaped load pick-up means (14), wherein the load pick-up means (14) has at least one load section (14a; 14b) which is arranged on the fork carrier (13) so as to be pivotable through substantially 90° about a substantially horizontal first pivot axis (D1) between a folded-out position and a folded-in position, characterized in that the fork carrier (13) is arranged on a lifting carriage (11) so as to be pivotable about a substantially horizontal second pivot axis (D2), wherein the lifting carriage (11) is arranged so as to be raisable and lowerable on the lifting device (9), and a positioning drive (25) is provided by means of which the fork carrier (13) is pivotable relative to the lifting carriage (11) about the second pivot axis (D2) and by means of which the at least one load section (14a; 14b) of the load pick-up means (14) is pivotable relative to the fork carrier (13) about the first pivot axis (D1).
2. Industrial truck according to Claim 1, characterized in that the positioning drive (25) is formed by a linear drive which, in a first adjustment range, pivots the fork carrier (13) relative to the lifting carriage (D1) about the second pivot axis (D2) and, in a second adjustment range, pivots the at least one load section (8a; 8b) of the load pick-up means (14) relative to the fork carrier (13) about the first pivot axis (D1).
3. Industrial truck according to Claim 1 or 2, characterized in that the positioning drive (25) is formed by a hydraulic cylinder (26) which is fastened by means of a cylinder housing (26a) to the lifting carriage (11) and which has a deployable piston rod (26b) which, in a first stroke range (H1), pivots the fork carrier (13) relative to the lifting carriage (11) about the second pivot axis (D2) and, in a second stroke range (H2), pivots the at least one load section (14a; 14b) of the load pick-up means (14) relative to the fork carrier (13) about the first pivot axis (D1).
4. Industrial truck according to Claim 3, characterized in that, on the piston rod (26b), there is arranged at least one first contact body (30a; 30b), which is operatively connected to a vertical contact surface (31a; 31b) of the lifting carriage (11), and at least one second contact body (32), which is operatively connected to a contact surface (33), which is inclined relative to the vertical, of the fork carrier (13).
5. Industrial truck according to Claim 4, characterized in that the vertical contact surface (31a; 31b) of the lifting carriage (11) extends over the first stroke range (H1) and the second stroke range (H2) of the piston rod (26b), and the inclined contact surface (33) of the fork carrier (13) extends over the first stroke range (H1) of the piston rod (26b).
6. Industrial truck according to one of Claims 3 to 5, characterized in that, on the piston rod (26b), there is arranged at least one third contact body (34a, 34b) which, in the second stroke range (H2) of the piston rod (26b), enters into operative connection with an actuating device (40) by means of which the at least one load section (14a; 14b) of the load pick-up means (14) is pivotable relative to the fork carrier (13) about the first pivot axis (D1) .
7. Industrial truck according to Claim 6, characterized in that the actuating device (40) has a first actuating lever (41) which is arranged articulatedly on the fork carrier (13) and on the at least one load section (14a; 14b) of the load pick-up means (14) .
8. Industrial truck according to Claim 7, characterized in that the actuating device (40) has a second actuating lever (42a; 42b) which is arranged articulatedly on the first actuating lever (41) and which is equipped with a receptacle (43a; 43b) for the third contact body (34a; 34b).
9. Industrial truck according to one of Claims 4 to 8, characterized in that a second contact body (32) is arranged on the piston rod (26a) between two first contact bodies (30a, 30b), and two third contact bodies (34a, 34b) are provided, between which the two first contact bodies (30a, 30b) and the second contact body (32) are arranged.
10. Industrial truck according to one of Claims 4 to 9, characterized in that the contact bodies (30a, 30b, 32, 34a, 34b) are formed as rollers arranged rotatably on the piston rod (26b).
11. Industrial truck according to one of Claims 3 to 10, characterized in that the first stroke range (HI) of the piston rod (26b) is greater than the second stroke range (H2) of the piston rod (26b).
12. Industrial truck according to one of Claims 1 to 11, characterized in that, between the lifting carriage (11) and the fork carrier (13), there is provided an end stop (50) which limits the pivoting movement of the fork carrier (13) relative to the lifting carriage (11).
13. Industrial truck according to Claim 12, characterized in that the end stop (50) is formed by an elastic element (51) which is connected to the fork carrier (13) and which interacts with a stop surface (52) of the lifting carriage (11).
14. Industrial truck according to Claim 13, characterized in that the elastic element (51) is formed as a sleeve (51a) which is arranged on a fastening rod (53) which is fastened to the fork carrier (13).
15. Industrial truck according to one of Claims 8 to 14, characterized in that the second actuating lever (42a; 42b) is formed as a thrust rod.
16. Industrial truck according to one of Claims 8 to 15, characterized in that the second actuating lever (42a; 42b) is equipped, at the receptacle (43a; 43b) for the third contact body (34a, 34b), with an insertion bevel (44) for the third contact body (34a; 34b).
17. Industrial truck according to one of Claims 8 to 16, characterized in that the second actuating lever (42a; 42b) is forced into an initial position by a spring (45).
18. Industrial truck according to one of Claims 1 to 17, characterized in that a sensor device (70) is provided by means of which the pivoting movement of the at least one load section (14a; 14b) of the load pick-up means (14) relative to the fork carrier (13) about the first pivot axis (D1) can be detected.
19. Industrial truck according to one of Claims 1 to 18, characterized in that the at least one load section (14a; 14b) of the load pick-up means (14) is, in the folded-out position, supported on a support surface (75) of the fork carrier (13).
20. Industrial truck according to one of Claims 1 to 19, characterized in that the at least one load section (14a; 14b) of the load pick-up means (14) can, in the folded-in position, come into contact with a stop (80) on a vehicle body of the industrial truck (1) .
21. Industrial truck according to one of Claims 1 to 20, characterized in that the hitch (20) is arranged on the fork carrier (13).
22. Industrial truck according to one of Claims 1 to 21, characterized in that, for the raising and lowering of the lifting carriage (11), a hydraulic lifting cylinder (12a) is provided, which is assigned a pressure-limiting valve (107) for limiting a maximum load for lifting.
23. Industrial truck according to one of Claims 3 to 22, characterized in that the hydraulic cylinder (26) is in the form of a double-acting hydraulic cylinder which is assigned a further pressure-limiting valve (112).

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