GB2369345A

GB2369345A - Locking unit

Info

Publication number: GB2369345A
Application number: GB0122860A
Authority: GB
Inventors: Walter Stowasser; Klaus Meissner; Hans Brenner; Klaus Conrad; Thomas Krebs; Michael Irsch; Jens Fery
Original assignee: Atecs Mannesmann GmbH
Current assignee: Atecs Mannesmann GmbH
Priority date: 2000-09-21
Filing date: 2001-09-21
Publication date: 2002-05-29
Anticipated expiration: 2021-09-21
Also published as: GB0122860D0; GB2369345B; GB0122511D0; JP2002128469A

Abstract

A locking unit 5 for a telescopic system having a main frame 1 and a plurality of telescopic sections 2 which are guided inside one another and can be moved out of a starting position into in each case at least one extended position. A drive 6 is provided for moving at least one driver bolt of a locking unit 5 into and out of a driver bolt opening, and for moving a coupling device for displacement of at least one locking bolt into and out of a locking bolt opening. The drive 6 is arranged fixedly on the main frame and a mechanical drive connection 7 is provided between the drive 6 and the locking unit 5.

Description

LOCKING UNIT

The present invention relates to a locking unit for a telescopic system of a hydraulically actuated telescopic jib of a crane having a jib box frame and a plurality of telecopic sections guided one inside another and moveable from a starting section position to an extended position, and to a telescopic jib.

EP 0 661 234 Al and counterpart U. S. Patent No. 5,628, 416 discloses a crane with a telescopic jib which has at least one box frame in which a plurality of telescopic sections of the jib are arranged, these sections being extendable from a starting position into, in each case, one extended position. In the starting position, the individual sections which are guided inside one another are secured to one another and/or to the box frame of the jib by means of a locking bolt. The extension and retraction of the individual sections is in each case effected by a single-stage piston-cylinder unit, which is releasably coupled to the section which is to be displaced by means of a locking unit. This coupling is effected by means of two driver bolts of the locking unit, which can be introduced in a positively locking manner into corresponding locking openings in the section which is to be moved. The driver bolts are held in the locking position by spring preloading and can be pulled out of the locking position, in order to be uncoupled in each case from the moved section of the jib, by means of a mechanism which is actuated by a hydraulic cylinder of the locking unit. The locking unit is equipped with a coupling device which can move relative to the locking unit and by means of which the

respective locking bolt can be gripped and pulled out of the locking opening. The locking bolt, like the driver bolt, is held in the locking opening by spring preloading and is unlocked counter to the spring force by the coupling device. A hydraulic drive by a piston-cylinder unit is provided for the unlocking movement of the coupling device. In this known crane, the free end of the piston rod of the single-stage piston-cylinder unit which is provided for movement of the individual sections is attached to the lower end (with respect to the working position) of the telescopic jib, while the locking unit is attached to the extendable cylinder housing (telescopic cylinder) of the piston-cylinder unit.

A telescopic system with a single-stage telescopic cylinder unit which functions in a similar way is known from EP 0 943 580 A2 and its counterpart U. S. Patent No.

6,216, 895. This system, however, does not use a single locking bolt to secure the individual sections to one another, but rather a pair of locking bolts which in each case engage in locking openings arranged in the side faces of the individual sections. The locking bolts lie opposite one another with respect to the longitudinal axis of the jib. To actuate the locking bolts, which are likewise held in the locking position under spring preloading, there is a separate hydraulic piston/cylinder unit, which acts on the locking bolts via a lever system.

DE 198 24 671 Al and its counterpart U. S. Patent No. 6,189, 712 discloses a telescopic crane, the sections of which can be moved telescopically by a single hydraulic piston-cylinder system. In this case, the displaceable part of the piston-cylinder system, i. e. either the piston rod or the cylinder housing, is equipped with two locking units, one of which is arranged at the upper end of the displaceable part and the other of which is arranged at the

lower end of the displaceable part. This makes it possible to considerably shorten the length of the piston-cylinder system with respect to the required length in the solution described in EP 0 661 234 Bl or EP 0 943 580 A2, for example to shorten this length by half. However, in this case the extension of a section is carried out in two steps; in the first step, the lower locking unit is used, and in the second step the upper locking unit is used. The reverse is true when retracting a section. In this known solution, the locking unit once again has two driver bolts which lie opposite one another and is designed to actuate an individual locking bolt for each section. In this case, the driver bolts and the locking bolt are actuated via a common drive of a hydraulic piston-cylinder system on the locking unit. This piston-cylinder system acts, via a cam-controlled mechanism, to convert the linear movement on the driver bolts and the locking bolt in such a manner that the locking bolt can only be unlocked when the two driver bolts have been introduced into the respective driver openings of the section which is to be moved. Conversely, the driver bolts can only be pulled out of the driver openings of the section in question when the locking bolt is in its locked position. This ensures that there can be no uncontrolled extension or retraction of a section without the guidance provided by the hydraulic telescopic piston-cylinder unit.

These known solutions have the drawback that, to actuate the locking units, which are fixedly connected to the movable part of the telescopic piston-cylinder system, it is necessary to provide hydraulic feedlines leading to this movable part. This requires a considerable construction and assembly outlay.

It is an object of the present invention to reduce the operational cost of a locking unit without impairing its operational reliability.

In accordance with the invention, there is provided a locking unit for a telescopic system comprising a main frame and a plurality of telescopic sections guided inside one another and each moveable along an axis from a starting position into at least one extended position, each of the telescopic sections having a driver bolt opening and at least one axially displaceable locking bolt receptive in a locking opening for fixing the section relative the next larger section or, in the case of the innermost section, relative the main frame, the locking unit being fixedly connected to an actuating means for displacing the telescopic sections and including at least one driver bolt that can be moved along the axis by a drive axis, the driver bolt being engageable in one of the driver bolt openings, a coupling device moveable by the drive relative to the locking unit, the coupling device being operable to grip and withdraw the at least one locking bolt out of the locking opening, wherein the drive is arranged fixedly on the main frame, and wherein there is a mechanical drive connection between the drive and the locking unit.

An important feature of the locking unit is that the drive for moving a driver bolt (two driver bolts are preferably provided) and for moving the coupling device in order to displace a locking bolt (two locking bolts are preferably provided) is arranged fixedly on the main frame and that there is a mechanical drive connection between this drive and the locking unit. Therefore, there are deliberately no hydraulics acting in the locking unit, and consequently the locking unit also does not have to be provided with hydraulic feed lines and outlet lines. It is also unnecessary to provide an electro-mechanical drive in the locking unit,

outlet lines. It is also unnecessary to provide an electro-mechanical drive in the locking unit, which would require corresponding electrical connection lines to the locking unit. To drive the locking unit, it is preferable to provide a rotary motor drive which is arranged in the region of the lower end of the frame, the mechanical drive connection comprising a torque transmission bar, which is arranged substantially parallel to the axis. In the locking unit there is a mechanism which converts the rotary movement of the bar into translational movements for the driver bolt (s) and the locking bolt (s). The bar may slidably engage a drive wheel, in particular a toothed wheel, which is mounted rotatably and in a fixed position on the locking unit. The rotary movement can be converted into the required translational movement for example by a rack drive, on which the drive wheel acts, or a crank drive or a slotted-guide control means.

Instead of a rotary drive movement, it is also possible for the drive, which is arranged outside the locking unit, to execute a sliding movement, which can be transmitted to the locking unit by a connecting rod. During the telescopic movement of a section, this connecting rod may be guided in a sliding manner in the locking unit and, when the desired locking position of the section is reached, can be fixedly connected to a coupling element of the locking unit in order to transmit linear movements. For this purpose, it is advantageously to provide a coupling fixture which can be engaged in a positively locking manner, in particular a coupling fixture which is designed as a driver projection and can be engaged by a rotary movement of the connecting rod. Alternatively, the connecting rod may also be of tubular design and the coupling fixture may be in the form of a spreading fixture which, for example, can be actuated mechanically by an actuating rod in the connecting rod, from the lower end of

the box frame of the telescopic jib. A spreading fixture of this type could also be activated and deactivated by a rotary movement of the actuating rod.

If two driver bolts are provided, it is advantageous for these bolts to be arranged on opposite sides with respect to the longitudinal axis of the frame. Correspondingly, when using two locking bolts, these locking bolts should also be arranged on opposite sides of the frame, preferably in the region of side faces of the respective section.

To ensure that the drive bolts and the locking bolts are held securely in their locking position when they are not actuated by the locking unit, it is preferable for the locking bolts and driver bolts to be fixed in engagement in the locking opening or driver opening by spring preloading.

A telescopic system according to the invention has at least one, and preferably two, locking units of the type described above, which are fixedly connected to the actuating means which effects the displacement of the individual telescopic sections, i. e. in the case of hydraulic actuation to the telescopic cylinder or, if appropriate, also to the piston rod of the hydraulic piston-cylinder system. Separate mechanical drives may be provided. Preferably, however, a common mechanical drive for both locking units is provided. In this case, it is particularly expedient to use a torque-transmission means of variable length, for example a telescopic torque-transmission means (e. g. profiled rods or tubes).

The invention will now be further described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a diagramatic depiction of a lateral side of a telescope jib embodying a locking unit in accordance with the invention ; Figure 2 is a view similar to figure 1 of another embodiment of the telescopic jib ; Figure 3 is a schematic depiction of a coupling device arranged with the locking unit and used for gripping and pulling a locking bolt out of a locking bolt opening; Figure 4 is a schematic showing of a toothed drive wheel employed with a mechanism to convert rotary movement to translative movements of the locking bolts and of driver bolts; Figure 5 is a schematic showing of a coupling element arrangement used when the drive executes a sliding movement transmitted to the locking unit via a connecting rod which is fixedly connected to the coupling element to transmit linear movement; Figure 6 is a schematic showing of a tubular connecting rod used with a spreading fixture coupling and having an actuating rod mechanically actuating the spreading fixture from a box frame lower end; and Figure 7 is a schematic showing of a variable length torque transmission means of a common mechanical drive for actuating two locking units in a telescopic jib.

Figure 1 shows a lateral section through a telescopic boom or jib, of which only the box frame 1 and a first telescopic section 2 are illustrated. Further sections, which adjoin the section 2, are not shown further for the sake of simplicity. However, U. S. Patent No.

5,628, 416 discloses a plural telescopic jib wherein the sections are guided inside one another

and provided with locking bolts. The lower end, in the working position, of the box frame 1 is denoted by reference numeral 9. A piston rod 4 of a hydraulic piston-cylinder unit for telescopic section extension, is attached to this lower end 9. The cylinder housing of the pistoncylinder unit is denoted by reference number 3. The cylinder housing 3 is the movable part of the piston-cylinder unit, but it is also possible to use a reverse arrangement for the movable part of the piston-cylinder unit. A locking unit 5 is attached to the lower end of the movable cylinder housing 3, so that this unit also moves when the hydraulic piston-cylinder unit is actuated. A rotary motor drive 6 (e. g. electric motor or hydraulic motor) is arranged in the region of the lower end of the box frame 1. The torque from this motor 6 can be transmitted by a profiled rod 7. This profiled rod 7 is operatively connected to a mechanism 8 on the locking unit 5. The mechanism 8 converts the rotary movement into corresponding linear movements for actuation of the driver bolts and locking bolts. To enable the locking unit 5 to move with the cylinder housing 3 without problems, the profiled rod 7 is guided in a sliding manner in the mechanism 8. On account of the profiled cross section of the profiled rod 7, it is ensured that it is always possible to transmit the torque produced by the motor 6 to the mechanism 8 (a positive lock). To convert the rotary movement into the movements required for actuation of the locking and driver bolt (s), it is possible, for example, to provide a rack which interacts with a toothed wheel driven by the profiled rod or to provide a crank drive. To realize the securing functions mentioned above (locking of the actuating means of locking and driver bolts), it is possible, for example, to provide slotted-guide control means for converting a rotary movement into translational movements, as known from U. S. Patent No. 6,189, 712.

It is also possible to use, as is well known, a rack drive or a crank drive for the aforemention conversion of rotary to translational movements.

Figure 2 shows an alternative embodiment. Like parts which have the same function are in each case provided with the same reference numeral as in Figure 1. The principal difference consists in the fact that, firstly, the lengths of the cylinder housing 3 and the piston rod 4 do not correspond to the entire length of the box frame 1, but rather only to approximately half the length of the box frame 1, and secondly that there are two locking units 5. Of the latter, one is attached to the upper end of the cylinder housing 3, and the other is attached to the lower end of the cylinder housing 3. These locking units 5 may, as illustrated in Figure 2, be actuated by a common mechanical drive (rotary drive 8 and profiled rod 7). Instead of a single-part profiled rod 7, it would advantageously also be possible to use a torque-transmission means of variable length, for example in the form of a telescopic profiledtube or rod element. A further alternative would be two rods which are mechanically coupled to one another in a rotationally fixed manner and interact with the drive 6. Naturally, it would also be possible to set up in each case one completely separate drive connection for each locking unit 5, i. e., for example, to provide two separate profiled rods which lead from a common rotary motor drive or in each a separate rotary motor drive, in the region of the lower end of the box frame 1, to the respective locking unit 5. Naturally it is also possible for the locking units 5 illustrated in Figure 2 to be arranged so as to function appropriately if the reverse arrangement of the piston-cylinder unit is used, i. e. the cylinder housing 3 is secured in the region of the lower end of the box frame 1. In such a case, one locking unit 5 may be

directly connected to the extendable end of the piston rod 4, while the second locking unit 5 is indirectly coupled to the piston rod 4 via a holding means (e. g. in the form of tie rods), which runs on the outer side of the piston rod 4 parallel to and at a distance therefrom, in the direction of the lower end of the box frame 1, so that this second (lower) locking unit is guided past the outside of the stationary cylinder housing 3 when the piston rod 4 is retracted and extended.

Referring to Figure 3, a coupling device 20 is arranged with locking unit 5.

The coupling device 20 is moveable relative to the locking unit 5 and is used to grip a driver bolt or a locking bolt 22 and pull it out of a bolt associated opening 24 in, e. g. , a telescopic section 26, this pulling out being effected against the bias of a spring holding, e. g. , the locking bolt in locked position.

For converting rotary drive to a linear movement with mechanism 8 and as shown in Fig. 4, a toothed drive wheel 30 is used to engage a rack 32 and drive it in a linear direction. The rack is couplable with a spring preloaded locking bolt 22 as at 34 so the bolt can be drawn from an associated locking opening against the preloading. Profiled rod 7 is guided slidably in drive wheel 30.

Figure 5 schematically depicts a coupling element 40 arranged with locking unit 5 and used where drive 6 executes a sliding movement. A connecting rod 7 transmits sliding movement, and during a section telescopic movement the connecting rod 7 is guided in the locking unit. The connecting rod 7 is fixably connectable to coupling element 40 when the telescopic section is in a locking position in order to transmit linear movements such linear

movements being depicted by arrow 46. The engagable connection of connecting rod 47 to coupling element 40 can, e. g., be with a positive locking coupling fixture 44.

As shown in Figure 6, the connecting rod 7 can be a tubular rod, and can include an actuating rod 48 therein. Coupling fixture 44 can comprise a spreading fixture, and the actuating rod 48 can mechanically actuate the spreading fixture from lower and 9 of the box frame.

Figure 7 depicts the common mechanical drive for actuating the two locking units 5 shown in the Figure 2 embodiment. The common mechanical drive includes a variable length torque transmission member 50 driven by drive 6. Transmission member 50 includes a first member length 52 attached to drive 6, and a second member length 54 telescopingly moveable within member 54. The transmission member can be of a profiled tube construction, or it could be of profiled rod construction.

Means are provided for permitting operation of the coupling device 20 to grip and pull out a locking bolt from an associated locking opening only when a driver bolt is received in its associated driver opening, such means being, e. g. , of the type disclosed in the above-mentioned U. S. Patent No. 6,189, 712.

The locking unit 5 has an extremely high degree of operational reliability and does not need any movable hydraulic or electrical lines to be laid in order to supply energy to and control the actuating device and the moveable locking unit.

Claims

1. A locking unit for a telescopic system comprising a main frame and a plurality of telescopic sections guided inside one another and each moveable along an axis from a starting position into at least one extended position, each of the telescopic sections having a driver bolt opening and at least one axially displaceable locking bolt receptive in a locking opening for fixing the section relative the next larger section or, in the case of the innermost section, relative the main frame, the locking unit being fixedly connected to an actuating means for displacing the telescopic sections and including at least one driver bolt that can be moved along the axis by a drive axis, the driver bolt being engageable in one of the driver bolt openings, a coupling device moveable by the drive relative to the locking unit, the coupling device being operable to grip and withdraw the at least one locking bolt out of the locking opening, wherein the drive is arranged fixedly on the main frame, and wherein there is a mechanical drive connection between the drive and the locking unit.

2. A locking unit according to claim 1, wherein the drive includes a rotary motor drive arranged proximal a lower end of the main frame, the mechanical drive connection comprising a bar arranged parallel to the axis for transmitting a torque output, the locking unit having a mechanism for converting rotary movement of the bar to translative movements of the at least one driver bolt and the at least one locking bolt.

3. A locking unit according to claim 2, further comprising a toothed drive wheel rotatably mounted in a fixed position on the locking unit, the bar slidably engaging the drive wheel.

4. A locking unit according to either claim 2 or claim 3, wherein the mechanism includes one of a rack drive, a crank drive, and a slotted-guide control means for converting rotary movement into translational movement.

5. A locking unit according to claim 1, wherein the drive is one which executes a sliding movement, a connecting rod for transmitting the sliding movement during telescopic movement of a section, the connecting rod being guided in the locking unit, the locking unit including a coupling element, the connecting rod being fixably connectable to the coupling element when the section is in a desired locking position in order to transmit linear motion.

6. A locking unit according to claim 5, further comprising a positive locking coupling fixture engageably connecting the connecting rod to the coupling element.

7. A locking unit according to claim 6, wherein the coupling fixture comprises a driver projection for engagement with a rotary movement of the connecting rod.

8. A locking unit according to claim 6, wherein the connecting rod is a tubular rod and the coupling fixture comprises a spreading fixture which can be mechanically actuated from a lower end of the main frame by an actuation rod.

9. A locking unit according to any preceding claim further comprising means for permitting operation of the coupling device to grip and pull out the at least one locking bolt from its associated locking opening only when the at least one driver bolt is received in its associated driver opening.

10. A locking unit according to any preceding claim, wherein the locking unit includes two driver bolts, which are disposed opposite one another with respect to the axis.

11. A locking unit according to any preceding claim, wherein each telescopic section has two locking bolts arranged opposite one another with respect to the axis.

12. A locking nut according to any preceding claim, wherein the at least one locking bolt and the at least one driver bolt are held engaged in respective locking and driver openings with a spring preloading.

13. A telescopic system having at least one locking unit as claimed in any preceding claim.

14. A telescopic system according to claim 13, wherein two locking units are provided fixedly connected to the actuating means.

15. A telescopic system according to claim 14, comprising a common mechanical drive for actuating each of the locking units.

16. A telescopic system as claimed in claim 15, wherein said common mechanical drive includes variable length torque-transmission means.

17. A locking unit substantially as described herein and illustrated in the accompanying drawings.

18. A telescopic system substantially as described herein and illustrated in the accompanying drawings.