EP1902997B1 - Crane with linked wireless control box - Google Patents

Description

Bridge cranes are used, for example, to transport workpieces or loads within a hall. For this purpose, fixed rails are mounted along the side walls of the hall, on which runs a crane bridge. The crane bridge is driven by one or more motors to move them from one hall position to another.

Like in the DE 42 09 535 A1 and the US 2003/0127635 A1 described runs along the crane bridge a cat, which is also set by electric motors in motion. On the cat is a hoist in the form of a cable or a chain hoist. Again, electric motors are provided to set the cable drum or the chain nut in motion.

The control of the individual drive motors is done by the user via a so-called control box or control pear. In the housing of the control box are manually operated buttons included to control the direction of movement and the speed of the individual drive motors.

In order to distribute the control commands from the control box to the individual drives, the control box is connected to the crane via a cable. The cable is hanging from the crane.

A similar facility is out of the woods DE 10207880 A1 known. Again, the system has a cat, which is provided with drive means and along a crane bridge is movable. On the cat a hoist is arranged, which is provided with drive means. There are provided control means in the form of a control panel for controlling the individual drive means. The keypad communicates with the controller via a radio link. Thus, the control means comprises receiving means for receiving control commands which control the movements of the individual drive means. The control panel forms a control box having manually operable buttons and transmitter means connected to the buttons which communicate with the receiving means to communicate manually input control commands to the control means.

The cable can either end at the cat, or there is a separate vehicle on the crane bridge for the control cable, which allows the crane operator to move in the longitudinal direction of the crane bridge, because the upper suspension point on the crane bridge can migrate. When attaching the cable to the cat, the possibility of movement of the crane operator is severely limited. Due to the height of the control box above the floor and the usual installation height results in a lateral clearance of about 2 m from the free-hanging position of the control box.

Another disadvantage of this solution is that the signal transmission of the control signals, which operate with very small electrical power, is not without problems at the contact points. There may be wire breaks leading to control errors.

However, these disadvantages are offset by the advantage that the control box is unambiguously assigned to the crane and because of the fixed connection with the crane also at any time can be found.

Furthermore, it is known from practice to connect the control box via a radio link signal technically with the crane. This eliminates the need for a control cable between the crane and the control box.

Another disadvantage of this solution is that the signal transmission of the control signals, which operate with very small electrical power, is not without problems at the contact points. There may be wire breaks leading to control errors.

However, these disadvantages are offset by the advantage that the control box is unambiguously assigned to the crane and because of the fixed connection with the crane also at any time can be found.

The newer way of transmitting the control commands in such overhead cranes is done wirelessly by means provided in the control box transmitting device which communicates with a receiving device on the crane. This type of communication avoids the disadvantages of transmitting extremely low power electrical signals to the control cables and also allows the crane operator substantially greater flexibility. He can move much further away from the crane, which is beneficial for certain loads.

This is offset by the disadvantage that the assignment of the control box to the crane is no longer clear and that the control box may be difficult to find within the hall because it is not placed by a crane operator as instructed at a specific agreed place.

Based on this, it is an object of the invention to provide a bridge crane, in which the advantages of the two systems are interconnected.

This object is achieved by a bridge crane with the features of claim 1.

In the new bridge crane a crane bridge is provided, which is provided with drive means to move along fixedly laid rails. Along the crane bridge runs a cat or trolley, which is also provided with drive means. On the cat or trolley is a hoist with its own drive means to lift using a lifting device in the form of a chain or a rope loads from the ground or other documents or lower it.

For controlling the individual drives control means are provided which have receiving means to receive control commands. There is further provided a control box having manually operable buttons and provided with a transmitting means which communicates with the receiving means for transmitting the control commands from the control box to the control means.

The control box is connected to the crane bridge via a linear connection means.

The linear connection now only ensures that the crane is clearly connected to its control box. Confusion of control boxes with several cranes within a hall are thereby inevitably excluded. Likewise, by the firm connection between Kran and its associated control box avoided the situation that possibly the control box within the hall is difficult to find again.

The control box may be a box of elongate shape having at least two buttons. The buttons can be operated directly or manually via a rocker.

The linear connection means connecting the control box to the crane may be a rope or a chain.

The flexibility on the part of the manufacturer is increased if a receiving device is provided on the connecting means, via which the connecting means to the control box is detachably or permanently connected. This makes it possible, where appropriate, to decouple the control box or to manufacture cranes that are delivered with or without connecting means, while on the other hand, the control box always has the same shape.

In order to avoid unauthorized disconnection of the control box from the connecting means, a lockable lock can be provided.

In order not to restrict the movement space of the crane driver unnecessarily, the connecting means may be crane-side connected to the cat or the trolley or its own vehicle, which is movable along the crane bridge. This additional vehicle does not have its own drive means but is passively moved by the crane operator by correspondingly to the connecting means or the control box pulls.

Typically, the control box hangs approximately at a height of 1 m to 1.20 m above the ground, resulting in a corresponding height of the bridge crane above the ground to the fact that the crane operator about 2 m to 3 m to move against the free-hanging control box to the side can. With a larger lateral movement would be due to the pendulum suspension of the control box reach a height in which a reasonable operation is no longer possible.

To counteract this, a connecting means may be provided whose length is greater than corresponds to the distance of the crane bridge from the ground. In order to prevent the control box from dragging on the ground, a drive device can be provided on the crane side, by means of which the linear connection means can be moved in the direction of the crane bridge. This drive means may be a spring motor in the simplest case, by which the linear connection means is resiliently biased in the rest position of about 1.20 m above the ground. Against the action of the spring motor, the crane operator can pull away the connecting means and thus receives a greater margin.

Such a solution would not be possible in conjunction with a control cable through which electrical signals pass, because there is a great risk of damaging the wires in the cable and, moreover, it is difficult to transfer data from the movable cable to a fixed position on the crane.

Depending on the form in which the line-shaped connecting means are designed, can drive to a sprocket or a rope drum / disc. The cable drum / disc can simultaneously serve as a memory to accommodate the excess amount of linear connection means. In the case of a chain for this purpose a bag-shaped chain memory is provided.

The line-shaped connecting means is advantageously associated with a stop to the retraction stroke of the linear connecting means in the direction of the crane bridge, i. away from the ground, to limit.

The hoist provided on the cat may be a cable pull or a chain hoist.

Incidentally, developments of the invention are the subject of subclaims.

The following description of the figures is limited to the explanation of the essential aspects of the invention. It is clear that a number of modifications are possible. Smaller, not described details, the expert can refer to the drawings in the usual way, which supplement the description of the figures so far.

Fig. 1

zeigt in einer perspektivischen Ausschnittsdarstellung einen erfindungsgemäßen Brückenkran;

Fig. 2

zeigt ein alternatives Ausführungsbeispiel des erfindungsgemäßen Brückenkrans mit einem eigenen Fahrzeug auf der Kranbrücke für das linienförmige Verbindungsmittel;

Fig. 3

zeigt in einer perspektivischen Darstellung einen Kettenzug, wie er an dem Kran verwendet werden kann;

Fig. 4

zeigt einen Seilzug in perspektivischer Darstellung, wie er an dem erfindungsgemäßen Kran verwendet werden kann;

Fig. 5

zeigt in einer vergrößerten Darstellung eine lösbare Verbindungsanordnung für die Steuerbox, in einer perspektivischen Ausschnittsdarstellung;

Fig. 6

zeigt eine mittels eines Federmotors vorgespannte Seilscheibe zum Aufwickeln bzw. Verkürzen der effektiven Länge des linienförmigen Verbindungsmittels; und

Fig. 7

zeigt eine durch einen Federmotor vorgespannte Kettennuss zum Verkürzen der effektiven Länge des linienförmigen Verbindungsmittels.

The following drawings are not necessarily to scale. To illustrate the essential details, it may be that certain areas are exaggerated in size.

Fig. 1

shows in a perspective sectional view of a bridge crane according to the invention;

Fig. 2

shows an alternative embodiment of the bridge crane according to the invention with a separate vehicle on the crane bridge for the linear connection means;

Fig. 3

shows in a perspective view a chain hoist, as it can be used on the crane;

Fig. 4

shows a cable in perspective view how it can be used on the crane according to the invention;

Fig. 5

shows in an enlarged view a releasable connection arrangement for the control box, in a perspective cutaway view;

Fig. 6

shows a biased by a spring motor pulley for winding or shortening the effective length of the linear connecting means; and

Fig. 7

shows a biased by a spring motor sprocket to shorten the effective length of the linear connecting means.

Fig. 1 shows in an enlarged schematic perspective view of a section of a bridge crane 1, which has a transverse to its longitudinal direction movable bridge carrier 2. At the ends of the bridge girder 2 sit two crane head carrier 3, of which only one can be seen because of the broken representation. The bridge girder consists of an I-profile with a top flange 4, a web 5 and a bottom flange 6. The bridge girder 2 is connected at the front end to the crane head carriers 3.

Each crane head carrier 3 forms a chassis and consists of two mutually parallel and attached side cheeks 7 and 8, between which wheels 9 are rotatably mounted. At least one of the wheels 9 is driven by a geared motor 11 so as to move the bridge crane along the fixed rails. The two wheels 9 of each crane carrier 3 accordingly provide a corresponding piece on the underside.

Along the crane bridge 2 runs a cat 12, which drives with the help of a total of 4 wheels 13 on the upper side of the lower flange 6. At least one of the wheels 13 is drivable by a drive motor, not shown, to move the cat 12 in the direction parallel to the longitudinal extent of the crane bridge 2 powered.

On the cat sits a hoist 14, from the underside of a load-carrying means 15 hangs down. The load-receiving means 15 is provided at its free lower end with a hook 16. The hook 16 serves to connect to the load receiving means 15 to be maneuvered load 17.

From the cat 12, a rope 18 depends down, at the lower free end of a control box 19 is attached. The control box 19 contains a plurality of buttons 21 for controlling the bridge crane 1. By selectively pressing buttons 21, the bridge 2 is set in motion in a known manner along its rails forward or backward. The actuation of other buttons 21 causes a movement of the cat 12 in the direction parallel to the longitudinal extent of the crane bridge 2, while another set of buttons controls the actual hoist 14 to raise or lower the load 17 at different speeds and directions.

The transmission of the input by the user via the buttons 21 control commands to the individual control devices using a contained in the control box 19 transmitting device 22 which cooperates with a receiving device 23 which is provided in the cat 12, for example in the hoist 14.

The other connections between the receiving device 23 and the individual control devices for the various drives are not shown in the drawing, since they are not the subject of the invention. The control devices themselves and their connection to the receiving device 23 are sufficiently familiar to the person skilled in the art from the prior art.

• Durch Betätigen der entsprechenden Taster 21 und Gedrückthalten wird der dem jeweiligen Taster 21 zugeordnete Antrieb in Bewegung gesetzt. Die Bewegung hält solange an, wie der Benutzer die Taste 21 betätigt hält. Der Steuerbefehl der manuell über den Taster 21 eingegeben wird, wird von der Sendeeinrichtung 22 der Steuerbox 19 drahtlos, beispielsweise per Funk, also auf dem Hochfrequenzweg an die Empfangseinrichtung 23 übermittelt. Die Empfangseinrichtung 23 setzt die empfangenen Signale in andere elektrische Signale um, die über Kabel (nicht veranschaulicht) an die einzelnen Steuereinrichtungen übermittelt werden.

The handling of the described bridge crane 1 is done as follows:

• By pressing the corresponding button 21 and holding it down the drive assigned to the respective push-button 21 is set in motion. The movement stops as long as the user holds the key 21 pressed. The control command, which is input manually via the push-button 21, is transmitted by the transmitting device 22 of the control box 19 wirelessly, for example by radio, that is, on the high-frequency path to the receiving device 23. The receiving device 23 converts the received signals into other electrical signals, which are transmitted via cables (not illustrated) to the individual control devices.

The control box 19 is connected via the cable 18 fixed to the cat 12 and thus inevitably runs with the crane back and forth. The purpose of the cable 18 is solely to uniquely connect the control box 19 with the crane 1. In this way, the control box 19 can neither be misplaced nor lost otherwise. It is inevitably close to the mechanical parts of the bridge crane 1. Incorrect operations due to incorrect assignment of overhead cranes, which are installed together in a hall, are excluded.

The rope 18 is so long that the control box 19 hangs in a comfortable working height of about 1.2 m above the ground. Depending on the height of the crane bridge 2 above the ground, the crane operator thus obtains a freedom of movement of about 2 m to 3 m radius of the circumference around the loosely hanging control box 19. At a further distance from the position of the cat 12 or the suspension point on the cat 12, the control box 19 would reach because of the fixed connection via the cable 18 in unergonomic heights.

In the bridge crane according to the invention, the rope is used 18 only the mechanical connection between the control box and the crane bridge.

To give the crane operator greater freedom of movement, it is possible to run on the crane bridge 2 another carriage 25, from which the rope 18 hangs down. On the rope 18, as before, the control box 19 is attached.

The carriage 25 has a chassis 26 on which a plurality of wheels 27 are freely rotatably mounted, which run on the top of the lower flange 6. The carriage 25 runs passively, i. he is moved or pulled by means of the rope 18 by the crane operator.

Instead of tying the control box 19 via a rope is also possible, as in Fig. 2 indicated schematically, this purpose to use a chain 28.

The carriage 25 can also run on a parallel to the crane bridge 2 laid separate bills.

The hoist 14 may be, for example, a chain hoist as it is used as a chain hoist 31 in FIG Fig. 3 is shown.

To the chain hoist 31 includes an asynchronous drive motor 32 which is coupled to the input side of a reduction gear 33. On the output side, the transmission drives a sprocket which is located in a sprocket housing 34. The sprocket housing 34 is formed in the known shape, so that the chain sprocket running therein is not recognizable because of the representation. To the chain nut around runs a chain 35, at the free end of the hook 16 is attached. The empty strand of the chain 35 runs into a sack-shaped chain storage, not shown.

At the top of the sprocket housing 34, two mounting flanges 36 are provided, with which the chain hoist 31 is attached to the cat 12. On the side remote from the gear side of the sprocket housing 34 is a control box 37 in which the necessary for the control of the motor 32 electromechanical parts are included. Alternatively, it is also possible to accommodate the receiving device 23 within the control device 37 and to transmit the control commands to the central crane control system from here.

Instead of a chain hoist, the bridge crane 1 according to the invention can also be provided with a cable 41. The cable 41 has attached to the cat 12 frame 42, on one side of a geared motor 43 is flanged. With the help of the geared motor 43, a cable drum 44 is selectively set in motion. From the circumference of the cable drum 44 runs a hoist rope 45, which leads to a hook bottle 46. On the hook block 46 of the hook 16 is attached. The hoist rope 45 forms from the view of the cable drum 44 behind the hook block 46, an empty strand 47 which is fixedly connected to the frame 42. The cable 44 is in this way a two-strand cable.

On the side remote from the geared motor 48 side, in turn, a control box 48 may be provided in the For example, as described in connection with the chain hoist 31, the receiving device 23 is housed.

Alternatively, the receiving device 23 may also be contained in the cat 12.

The necessary for the transmission of the necessary drive power and the control commands cables are not shown, since they are not important for the understanding of the invention.

Fig. 5 shows in an enlarged sectional view schematically a detachable connection between the cable 18 and the chain 28 and the control box 19. Such a detachable connection may be required if for maintenance or because certain, very large parts are unfavorable to maneuver, it is expedient to maneuver the overhead crane 1 in the known manner, as is common in wireless control boxes.

The embodiment shown is merely one of the conceivable solutions, with the sole purpose here being to explain the principle of the detachable connection in order to selectively unlatch the normally tethered control box 19.

The connecting arrangement 51 may, for example, have a cylindrical pin 52 fastened to the free end of the cable 18 or the chain 28, which is provided with a circumferential annular groove 53 in the vicinity of its lower end. The pin 52 represents the actual coupling means, which is insertable into a bore 54 on an upper side 55 of the control box 19. Within the control box 19 is seated axially displaceable with a key to be operated profile cylinder 57 which is oriented so that its direction of movement is tangent to the leading from top to bottom into the control box 19 bore 54. On the profile cylinder, a pin 58 is fixed, whose diameter is matched to the width of the annular groove 53.

With the help of the lockable profile cylinder 57, the pin 58 can be brought from a position in which it projects into the clearance of the bore 54, in a position in which it is withdrawn from the gauge.

• Um die Steuerbox 19 mit dem Seil 18 bzw. der Kette 28 zu verbinden, wird mit Hilfe eines nicht gezeigten Schlüssels der Profilzylinder 57 in eine Stellung gebracht, in der er aus der Steuerbox 19 vorragt, so dass der an dem Profilzylinder 57 befestigte Bolzen 58 aus dem Lichtraumprofil der Bohrung 54 zurückgezogen ist. Sodann wird von oben her der Zapfen 51 in die Bohrung 54 eingesteckt. Durch Anschläge wird die Einstecktiefe definiert. Wenn die gewünschte Einstecktiefe erreicht ist, wie sie durch die Anschläge festgelegt ist, wird der Profilzylinder 57 in die Steuerbox 19 eingedrückt, wodurch der damit verbundene Bolzen 58 in die Ringnut 53 eingreift. Durch bekannte Schließmechanismen wird der Profilzylinder 57 in der eingedrückten Stellung fixiert. Es wird damit eine formschlüssige Verbindung zwischen dem Seil 18 bzw. der Kette 28 und der Steuerbox 19 erhalten. Die formschlüssige Verbindung lässt sich nur lösen, indem durch Einstecken eines Schlüssels in den Profilzylinder 57 der Profilzylinder in eine Stellung gedreht werden kann, so dass er aus dem Steuerboxgehäuse 19 ein Stück weit zurückgezogen werden kann, bis der Zapfen 58 die Nut 53 freigibt.

The handling is as follows:

• To connect the control box 19 with the cable 18 and the chain 28 is brought by means of a key, not shown, the profile cylinder 57 in a position in which it protrudes from the control box 19, so that the attached to the profile cylinder 57 bolt 58th is withdrawn from the clearance space of the bore 54. Then, the pin 51 is inserted into the bore 54 from above. Stops define the insertion depth. When the desired insertion depth is reached, as determined by the stops, the profile cylinder 57 is pressed into the control box 19, whereby the bolt 58 connected thereto engages in the annular groove 53. By known locking mechanisms of the profile cylinder 57 is fixed in the depressed position. It is thus obtained a positive connection between the cable 18 and the chain 28 and the control box 19. The positive connection can only be solved by turned by inserting a key into the profile cylinder 57 of the profile cylinder in a position can be so that it can be withdrawn from the Steuerboxgehäuse 19 a piece until the pin 58, the groove 53 releases.

In this way, it is ensured that the control box 19 can only be used mechanically separated from the bridge crane 1 by specially authorized personnel.

As already mentioned above, the radius of action of the crane operator is limited when the control box 19 is connected to the crane bridge 2 via the cable 18. In order to increase the radius of action, in the case of a cable 18, a take-up device 61 may be used which is installed, for example, in the cat 12.

To the take-up device 61 includes a pulley or cable drum 62, at one end of the rope 18 is attached. The pulley 62 is freely rotatably mounted on a shaft 63 fixed in the cat 12. The axis 63 itself is rotatably connected to the cat 12.

On the viewer side facing the pulley 62 includes a pocket-shaped recess 64, which serves as a receiving space for a spiral belt spring 65. The coil spring 65 is connected at one end to the axis 63 and at the other end to the pulley 62nd

By means of a person sitting on the rope 18 rider 66, which cooperates with a stationary stop on the cat 12, the winding of the rope 18 is limited to the pulley 62.

• In der Ruhestellung, wenn der Reiter 66 an dem entsprechenden Anschlag der Katze 12 anliegt, befindet sich die Steuerbox 19 in der üblichen Höhe von etwa 1,20 m über dem Boden einer Halle, in der der Brückenkran 1 installiert ist. Wenn der Kranführer einen größeren Bewegungsbereich braucht, d.h. einen größeren Abstand von der angehängten Last einnehmen muss, zieht er die Steuerbox 19 zu sich her, womit zusätzlich Seil 18 von der Seilscheibe 62 abgewickelt wird. Die zwischen der drehfest gehalterten Achse 63 und der Seilscheibe 62 wirksame Spiralfeder 65 ist ständig bestrebt, das Seil 18 zurückzuziehen und wieder aufzuwickeln, wodurch das Seil gespannt gehalten wird. Für den momentanen Anwendungszweck steht jedoch eine zusätzliche Länge an Seil 18 zur Verfügung, die es dem Kranführer ermöglicht, sich weiter von der Katze 12, und damit der angehängten Last 17, zu entfernen. Wenn der Kranführer auf die Katze 12 zugeht, wird automatisch das Seil 18 wieder auf die Seilscheibe 62 aufgewickelt, bis der Reiter 66 am Anschlag anliegt, womit die konstruktive Höhe der Steuerbox 19 über dem Boden erreicht ist.

The operation of the illustrated arrangement is like follows:

• In the rest position, when the rider 66 rests against the corresponding stop of the cat 12, the control box 19 is in the usual height of about 1.20 m above the floor of a hall in which the bridge crane 1 is installed. If the crane operator needs a larger range of motion, ie has to take a greater distance from the attached load, he draws the control box 19 to her, which in addition rope 18 is unwound from the pulley 62. The effective between the rotatably supported axis 63 and the sheave 62 spiral spring 65 is constantly anxious to retract the rope 18 and rewind, whereby the rope is kept taut. For the current application, however, an additional length of rope 18 is available, which allows the crane operator, further from the cat 12, and thus the attached load 17 to remove. When the crane operator approaches the cat 12, the rope 18 is automatically rewound onto the pulley 62 until the rider 66 abuts the stop, thus reaching the constructive height of the control box 19 above the ground.

The amount of rope 18 that can be removed from the sheave 62 is constructively determined by the amount of rope stored on the sheave 62.

If a chain 28 is used as a linear connecting means between the control box 19 and the crane bridge 2, instead of the illustrated arrangement according to FIG Fig. 6 to increase the operating radius a sprocket 71 are used as a drive means 61. This is a sprocket, as well as for example to drive the chain 35 is used.

The sprocket 71 contains corresponding chain pockets 72 for receiving chain links 73 of the chain 28. The sprocket 71 is in turn mounted rotatably in the cat 12 and is connected via a schematically indicated spring motor 74 which is connected via a dashed line 75 with the sprocket 71, in the winding, ie biased in the sense of shortening the effective length of the chain 28. The excess portion of the chain 28 is collected in a chain store, not shown.

Instead of arranging the spring motor 74 axially adjacent to the sprocket 71, it can also, as in Fig. 6 shown within a recess in the flank of the sprocket 71 are housed.

To a bridge crane belongs a control box, which communicates with the control device, which controls the individual drives of the bridge crane, by wireless way. In order to obtain a clear association between control box and mechanical parts of the crane, the control box is connected to the bridge girder via a chain or rope.

Claims (20)

1. Gantry crane (1)
   with a crane bridge (2), which is provided with drive elements (11) and runs along fixedly laid rails,
   with a trolley (12), which is provided with drive elements and is movable along the crane bridge (2),
   with a hoist (14), which is arranged on the trolley (12) and is provided with drive elements,
   with control elements (37, 48) for controlling the individual drive elements (11, 33, 43), wherein the control elements (37, 48) have receiving elements (23) to wirelessly receive control commands, which control the movements of the individual drive elements (11),
   with a control box (19), which has manually operable control switches (21) and transmitting elements (22) that are connected to the control switches (21) and communicate wirelessly with the receiving elements (23) to transmit manually input control commands to the control elements (37, 48)
   characterised by a linear connecting element (18, 28), which is connected to the control box (19) at one end and to the crane bridge (2) or the trolley (12) at the other end.
2. Gantry crane according to claim 1, characterised in that the control box (19) has an elongated shape with at least two control switches (21).
3. Gantry crane according to claim 2, characterised in that the control switches (21) are operable with a rocker switch or a joystick.
4. Gantry crane according to claim 1, characterised in that the linear connecting element (18, 28) is a cable.
5. Gantry crane according to claim 1, characterised in that the linear connecting element (18, 28) is a chain.
6. Gantry crane according to claim 1, characterised in that a connection device (51) is provided between the linear connecting element (18, 28) and the control box (19).
7. Gantry crane according to claim 1, characterised in that the control box (19) is detachably or undetachably connected to the connection device (51).
8. Gantry crane according to claim 1, characterised in that the linear connecting element (18, 28) is connected to the trolley (12).
9. Gantry crane according to claim 1, characterised in that a vehicle (25), which is independent of the trolley (2) and to which the linear connecting element (18, 28) is fastened, runs on the crane bridge (2).
10. Gantry crane according to claim 1, characterised in that a rail, on which a vehicle (25), which is independent of the trolley (2) and to which the linear connecting element (18, 28) is fastened, runs parallel to the crane bridge (2).
11. Gantry crane according to claim 1, characterised in that the linear connecting element (18, 28) has a length that exceeds the distance of the trolley (12) or the crane bridge (2) from the ground.
12. Gantry crane according to claim 11, characterised in that a drive arrangement (61) is provided on the crane side, by means of which the linear connecting element (18, 28) is movable in the direction of the crane bridge (2).
13. Gantry crane according to claim 12, characterised in that the drive arrangement (61) has a spring motor (65).
14. Gantry crane according to claim 12, characterised in that the drive arrangement (61) comprises a sprocket (71).
15. Gantry crane according to claim 12, characterised in that a storage means (62) is provided on the crane side to receive an excess portion of the linear connecting element (18, 28).
16. Gantry crane according to claim 15, characterised in that the storage means is formed by a chain cavity.
17. Gantry crane according to claim 15, characterised in that the storage means (62) is formed by a drum, onto which the linear connecting element (18) can be wound.
18. Gantry crane according to claim 11, characterised in that the linear connecting element (18, 28) has an associated stop (66), which restricts the return stroke of the linear connecting element (18, 28) in the direction of the crane bridge (2).
19. Gantry crane according to claim 1, characterised in that the hoist (14) is a cable hoist (41).
20. Gantry crane according to claim 1, characterised in that the hoist (4) is a chain hoist (31).

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