The invention relates to a mobile crane comprising a main jib which is mounted in a luffable manner thereon and can be raised by means of a luffing cylinder, and comprising a main jib extension which is releasably connected to a main jib head of the main jib by means of upper and lower bolts, the main jib extension, proceeding from a basic position after release of the upper or lower bolts, can be angled relative to the main jib about a luffing axis by means of an angling drive, the angling drive engages a foot of the main jib extension, a maximum angling angle is limited by an adjustable angling plate and the angling plate engages the foot of the main jib extension and the main jib head.
The invention also relates to a method for angling a main jib extension relative to a main jib of a mobile crane.
The German utility model DE 20 2004 020 760 U1 already discloses a mobile crane comprising a main jib and a main jib extension which is fastened to its main jib head. The main jib extension can be luffed from a basic position, in which the main jib extension is oriented with its longitudinal direction in extension of the longitudinal direction of the main jib, to a 20° position and a 40° position. Typically, the main jib extension is releasably fastened to the main jib head by means of two lower bolts arranged in the region of bottom chords of the main jib extension and by means of two upper bolts arranged in the region of top chords of the main jib extension. In order to be able to luff the main jib extension out of the basic position about the lower two bolts serving as a luffing axis, in a first step the two upper bolts are withdrawn and in a second step the luffing of the main jib extension is effected by means of hydraulic luffing cylinders which engage the main jib head and the main jib extension. The two upper bolts are inserted and withdrawn in each case by means of a hydraulic bolting cylinder. In order to supply power to the luffing cylinders and the bolting cylinders, an autarkical hydraulic unit is arranged on the lower end of the main jib extension. The hydraulic unit used can be e.g. a diesel motor or electric motor each having an associated hydraulic pump.
German patent document DE 103 21 493 B4 discloses a mobile crane comprising a main jib extension and an angling plate. The angling plate is designed as a mechanically lockable telescopic apparatus having a tubular guiding plate and a sliding plate which is guided and extendible therein and is likewise tubular. The guiding plate has stop openings for receiving bolts which serve to support the sliding plate at its lower end and thus permit a preselected length of the angling plate and thus angular adjustment of the main jib extension. The angling plate is arranged in the region of a bottom chord of the main jib and the main jib extension. The desired angling is achieved by raising the main jib, whereby the angling plate is reduced in length until the sliding plate impinges upon the bolt and is supported thereon.
Moreover, European patent application EP 2 253 576 A1 discloses another embodiment of an angling plate for angling a main jib extension of mobile cranes. The angling plate which is formed from two angle levers has, in its basic position which corresponds to a 0° position of the main jib extension with respect to the main jib, several pairs of aligned stop openings for bolts. By selecting one pair of the stop openings for the bolts, the length of the angling plate can be varied and the main jib extension can be fixed in various angular positions, preferably 0°, 20° and 40°. The actual angular movement of the main jib extension is effected by means of a lifting machine located on the crane or next to the crane.
The present invention provides a mobile crane and a method for angling a main jib extension relative to a main jib of a mobile crane, by means of which the angling of the main jib extension is simplified.
In accordance with the invention, in the case of a mobile crane comprising a main jib which is mounted in a luffable manner thereon and can be raised by means of a luffing cylinder, and comprising a main jib extension which is releasably connected to a main jib head of the main jib by means of upper and lower bolts, the main jib extension, proceeding from a basic position after release of the upper or lower bolts, can be angled relative to the main jib about a luffing axis by means of an angling drive, the angling drive engages a foot of the main jib extension, a maximum angling angle is limited by an adjustable angling plate and the angling plate engages the foot of the main jib extension and the main jib head, a simplification is achieved by virtue of the fact that the angling drive is a component of an angling plate in the form of a combi-angling plate. In an advantageous manner, a known passive, mechanically limiting angling plate is converted into a hydraulically supported combi-angling plate which also provides the mechanical limitation. By integrating the angling drive into the combi-angling plate, it is not necessary to provide any additional force transmission points on the main jib head or the main jib extension. The angling per se is effected as far as possible on the ground or at the storage position of the main jib so that it is not necessary to work far above the upper edge of the mobile crane. The invention permits angling of the main jib extension in a mobile crane which stands on flat ground and has a horizontally oriented telescopic jib. For the last part of the luffing of the main jib extension to a 20° or 40° position, the luffing cylinder of the main jib is used. Since the extension path of the hydraulic cylinder of the angling drive can be freely selected, the angling drive can be configured relatively independently of the terrain when the extension path is selected to be longer.
Since the combi-angling plate engages in the region of the foot of the main jib extension, a fork head offset, which compensates for a deformation of the main jib extension, is not required between the main jib and main jib extension. It is particularly important in the case of long slender jib systems. As a result, it is also not necessary to provide an auxiliary cylinder, by means of which a fork head offset must be compensated for.
Preferably, provision is made that the angling drive engages the main jib head on the one hand and engages the main jib extension on the other hand. In particular, the angling drive is designed in this case such that the main jib extension can be raised and lowered so as to pivot about the luffing axis against the effect of the gravitational force of the main jib extension.
In one advantageous embodiment, provision is made that the main jib extension, proceeding from a basic position after release of the upper bolts, can be angled about a luffing axis in the region of a bottom chord of the main jib extension by means of the angling drive, and the angling drive engages in the region of the top chord of the main jib extension.
It is particularly advantageous that the angling drive is designed as a hydraulic cylinder having a housing and rod.
In one structurally simple and advantageous embodiment, provision is made that the combi-angling plate consists of a sliding plate, a guiding plate and the angling drive, the angling drive drivingly engages the sliding plate on the one hand and the guiding plate on the other hand and the sliding plate can be displaced relative to the guiding plate by means of the angling drive. In particular, the angling drive in this case is releasably fastened to the sliding plate. In a particularly preferred manner, the sliding plate is pivotably mounted on the main jib head, the guiding plate is pivotably mounted on the main jib extension, the sliding plate is guided in the guiding plate and a maximum displacement of the sliding plate in the guiding plate can be limited by means of a stop bolt.
In accordance with the invention, in the case of a method for angling a main jib extension relative to a main jib of a mobile crane, in particular a mobile crane as described above, wherein the main jib is mounted in a luffable manner on the mobile crane and can be raised by means of a luffing cylinder, the main jib extension is releasably connected to a main jib head of the main jib by means of upper and lower bolts, an angling drive engages a foot of the main jib extension, a maximum angling angle is limited by an adjustable angling plate and the angling plate engages the foot of the main jib extension and the main jib head, a simplification is achieved by virtue of the fact that by means of the angling drive which is a component of an angling plate in the form of a combi-angling plate, the main jib extension, proceeding from a basic position, is raised relative to the main jib about a luffing axis as far as until the upper or lower bolts are relieved, then the upper or lower bolts are removed, at least one combi-angling plate is inserted, or has already been inserted, between the main jib head and a top chord or bottom chord of the main jib extension, the main jib extension is lowered by means of the angling drive for as long as until the maximum angular position is reached or a head of the main jib extension comes to rest on a ground, the angling drive is drivingly separated from the combi-angling plate and if the maximum angular position is not yet reached, the main jib is raised in order to angle the main jib extension until the desired angling angle is achieved. With regard to the advantages associated with this, reference is made to the previous statements relating to the mobile crane.
Preferably, provision is made that the main jib extension, proceeding from a basic position, is raised relative to the main jib about a luffing axis as far as until the upper bolts are relieved, then the upper bolts are removed, at least one combi-angling plate is inserted, or has already been inserted, between the main jib head and a top chord of the main jib extension.
In the context of the present invention, a mobile crane is understood to be both a movable telescopic crane and a movable crawler crane comprising a lattice mast jib.
The invention will be explained in greater detail hereinafter with reference to an exemplified embodiment illustrated in the drawings.
This main jib extension 1 is divided into a basic jib 1a which is designed as a lattice mast and typically has a truss pipe construction, and a tip 1b which adjoins said basic jib and is designed as a box jib. In
Basically, such main jib extensions 1 are constructed as modular systems from individual main elements and can be assembled depending upon the requirement of the length or load-bearing capacity thereof. The individual main elements have dimensions allowing transportation and in most cases are not also carried with the telescopic crane but instead are transported separately. If the axle loads of the telescopic crane and the installation size of the main jib extension 1 allow, the main jib extension 1 can also be carried if required. This would then be located in a transport position laterally next to and in parallel with the main jib 2. The individual main elements are connected to one another by means of bolt connections to form the desired main jib extension 1. The attachment to the main jib head 2a can be effected using main elements or as a preassembled unit or units.
In order to be able to angle the main jib extension 1 relative to the main jib head 2a or main jib 2, provision is made to withdraw the two upper bolts 4c at the bolting points A and B in the region of a top chord 1d of the main jib extension 1 so that the main jib extension 1 can be angled relative to the main jib 2 about the lower spindle 4d in the region of the lower bolting points C and D in the region of a bottom chord 1e of the main jib extension 1 about the angling angle b. The lower spindle 4d thus forms the luffing axis w. Instead of the spindle 4d, the bolts 4c could also be used if they were aligned horizontally. The angling angle b is typically in the range of 0° to 40°. In order to limit the angling angle b or to be able to set it to the typical angling angle values of 20° and 40°, two so-called angling plates 5 are provided, one of which is designed as an active combi-angling plate 6. The angling plate 5 and the combi-angling plate 6 extend in the region of the longitudinal sides of the top chord 1d of the main jib extension 1 and in parallel with one another.
The passive angling plate 5, by means of which a displacement path and therefore the angling angle b can be manually limited by means of a stop surface 5a, consists substantially of a sliding plate 5b having a long hole-shaped guiding opening 5c, at which a guiding plate 5d can be guided in the longitudinal direction c along a sliding plate 5b. The sliding plate 5b is designed as an elongated flat profile having the stop opening 5c and extends substantially in parallel with the longitudinal direction v of the main jib extension 1. At an end facing the main jib head 2a, the sliding plate 5b has a bore, via which the sliding plate 5b is releasably fastened to the main jib head 2a at the bolting point E by means of a bolt 5e. The bolt 5e is oriented with its longitudinal extension in parallel with the spindle 4d. Slid onto the sliding plate 5b is the guiding plate 5d which for this purpose has a closed rectangular cross-section with a guiding opening 5f (see
The active combi-angling plate 6 is comparable in terms of the structure of the manual part with the above-described passive angling plate 5 and correspondingly has a stop surface 6a, a sliding plate 6b, a stop opening 6c, a guiding plate 6d, a bolt 6e, a guiding opening 6f, a stop bore 6g, a stop bolt 6h which corresponds to the stop bolt 5h and is also defined as a bolt 6p, and a bolt 6i. In the exemplified embodiment, the stop bolt 6h and the bolt 6p are the same and are provided with different terms and reference signs only in relation to their insertion location. Two bolts can also be provided next to one another but the function of the active combi-angling plate 6 does not provide a simultaneous use of the stop bolt 6h and bolt 6p which means that only one bolt can be provided for this purpose. The bolt 6e is releasably fastened to the main jib head 2a in a bolting point F and the bolt 6i is releasably fastened thereto at a bolting point H. The stop bolt 6h is not inserted in the basic position with the angling angle b of 0°.
Compared with the passive angling plate 5, the active combi-angling plate 6 is supplemented by a drive 6j in order to be able to actively displace the guiding plate 6d relative to the sliding plate 6b. For this purpose, the sliding plate 6d is provided, at its end opposite the main jib head 2a, with an angle bracket 6m, at which the angling drive 6j consisting of two hydraulic cylinders extending mutually in parallel and having housings 6k and a rod 6l are connected on the housing side. The hydraulic cylinders extend in the c longitudinal direction of the angling plate 5 or combi-angling plate 6. In order to connect the angling drive 6j or the hydraulic cylinders extending mutually in parallel and having its rods 6l to the sliding plate 6b of the combi-angling plate 6, the sliding plate 6 is extended with respect to the passive angling plate 5 by a rod part 6n in order to form an abutment for the angling drive 6j. Arranged at the end of the rod part 6n opposite the main jib head 2a is a bore 6o (see
The angling drive 6j is dimensioned such that only the empty weight of the main jib extension 1 can be angled down or up.
The angling of the main jib extension 1, which is located in the basic position shown in
In a next step, the angling drive 6j is again actuated and the rods 6l of the hydraulic cylinders are slowly retracted. As a result, the sliding plate 6b is slid relative to the guiding plate 6d in the direction of the main jib 2 via the coupling part 6q so that the spaced interval between the bolting points G, H and E, F is increased and the main jib extension 1 pivots about the angling angle b via the spindle 4d of the bolting points C, D arranged in the region of the bottom chord 1d. By reason of this angling movement, the head 1f of the main jib extension 1 is lowered in the direction of the ground 3 until it contacts the ground 3. The angling drive 6j is then retracted slightly further, whereby the bolt 6p in the bore 6o is relieved and is then transferred as a stop bolt 6h to the stop bore 6g. This has the advantage that, during the setting-up procedure, it is not forgotten to decouple the angling drive 6j and the angling drive is no longer involved in the main flow of forces when a load is being lifted. The desired maximum displacement path is also set at the angling plate 5 previously or at the latest at the present time in order to permit or limit the angling of the main jib extension 1 to the 20° position or 40° position.
In a further step, by luffing the main jib 2 about the luffing angle a the main jib extension 1 is angled further and the tip 1f of the main jib extension 1 slides therethrough across the ground 3 in the direction of the main jib 2. By means of the luffing action, the main jib extension 1 is angled further for as long as until the angling plate 5 and the combi-angling plate 6 limit the angling in a preselected position. At the point in time the angling movement is limited in the 40° position by the angling plate 5 and the combi-angling plate 6, the tip 1f is still just about in contact with the ground 3. During further luffing of the main jib 2, the main jib extension 1 lifts from the ground 3 in the 40° position. This position, in which the main jib extension 1 is located in a 40° position with respect to the main jib 2, is illustrated in
Back-fitting or angling-up the main jib extension 1 is performed in the reverse sequence.
The substantial difference in this alternative sliding plate 6b compared with the previously described sliding plate 6b is that this sliding plate 6b is not flat profile-shaped over its entire length but instead is formed, at least in the region of the stop opening 6c and the bore 6o, from two flat profile-shaped sliding plate parts 6b′, 6b″ which extend in parallel and spaced apart from one another in order to receive therebetween the angling drive 6j which is designed as a hydraulic cylinder. The sliding plate 6b also has, in addition to the stop opening 6c, a bore 6o in the region of its centre in order to releasably connect the rod 6l of the angling drive 6j to the sliding plate 6b by means of the bolt 6p. This bore 6o is also used as a stop surface 6a′ for the stop bolt 6h or bolt 6p in the 20° position. The further bolt which is shown in
The guiding plate 6d shown in
Although, in connection with the present exemplified embodiment, the main jib 2 is described as a telescopic jib and the main jib extension 1 is described as a lattice mast jib comprising a box tip, the invention can also be applied to other embodiments of main jib 2 and main jib extension 1. The main jib 2 can also be a lattice mast jib or a combination of telescopic jib, lattice mast jib and/or box jib. Lattice mast jibs or box jibs or combinations thereof are feasible for the main jib extension 1.
Furthermore, the exemplified embodiment relates to the use of an angling plate 5 and a combi-angling plate 6. Instead of providing one angling plate 5 and one combi-angling plate 6, it is also possible to provide two combi-angling plates 6 which are each arranged in the edge region of the top chord 1d of the main jib extension 1. This embodiment comprising two combi-angling plates 6 without an angling plate 5 is preferred. The use of a single combi-angling plate 6 which is arranged centrally in relation to the width of the top chord 1d of the main jib extension 1 is also feasible. Furthermore, the combi-angling plate 6 has been described up to this point as a tension member. An embodiment as a compression member is also feasible as is the arrangement in the bottom chord region. It is also feasible that the luffing axis w is then arranged in the region of the top chord 1d. The foot 1c of the main jib extension 1 is correspondingly chamfered, preferably in the form of an adapter, in order to permit angling of the main jib extension 1 about the upper luffing axis w.
Number | Date | Country | Kind |
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10 2015 119 379.5 | Nov 2015 | DE | national |
The present application claims the priority benefits of International Patent Application No. PCT/EP2016/077002, filed Nov. 8, 2016, and claims benefit of German patent application DE 10 2015 119 379.5, filed Nov. 10, 2016.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2016/077002 | 11/8/2016 | WO | 00 |