The present invention relates to a telescopic crane of a type having a substructure, a revolving superstructure mounted to the substructure, a counterweight and a boom structure comprised of a main boom having a boom base and at least one telescope section which is received in the boom base and displaceable between retracted and extended positions.
In extended position, telescopic cranes are exposed to varying degrees of stress depending on the angular disposition. Oftentimes, the lateral deformation of the main boom in steep-incline disposition is the criterion that limits the load-carrying capability. When the angular disposition is flat or average, the loads applied in the mounting of the extended telescope sections represent a crucial criterion for the maximum load-carrying capability. In the latter case, the so-called super lift operation has been developed for torque relief.
The use of telescopic cranes with super lift operation has been known for a long time. An example is illustrated in a brochure issued by Mannesmann Demag Fördertechnik, Demag AX 1600, April 1996, pages 5, 17 and 27. A guy truss is arranged on the boom base of the main boom for placement on the boom base to increase the load-carrying capability and to reduce sag of the main boom. The guy truss is connected, on the one hand, to the foot region of the main boom via a guy rope of substantially constant length, and, on the other hand, to the head or collar of one of the inner telescope sections via a further guy rope of normally variable length. This reinforcing configuration is applicable for the base unit alone, or in conjunction with the arrangement of a fly jib in the form of a latticed tower which can be of the fixed type or luffing type. Telescopic cranes of this kind suffer shortcomings because the boom structure deforms laterally, especially in steep-incline disposition.
It is thus an object of the present invention to provide an improved telescopic crane, obviating the afore-stated drawbacks.
In particular, it is an object of the present invention to provide an improved telescopic crane whose lateral deformation of the boom structure is significantly reduced, in particular in steep-incline disposition, compared to conventional telescopic cranes.
These objects, and others which will become apparent hereinafter, are attained in accordance with the present invention by providing at least one guy support which is mounted to the boom structure and connected to a tension means extending substantially longitudinally in the direction of the boom structure, with the guy support oriented with respect to the luffing plane at an inclination which is so selected that a lateral load acting on the boom structure is partially or entirely received by the guying.
The inclination of the guy support can be realized transversely to the longitudinal direction or in longitudinal direction or in superimposed transversely to and longitudinally in direction of the boom structure.
According to another feature of the present invention two inclined guy supports can be provided on the topside of the respective boom element of the boom structure, whereby the angular disposition of both guy supports is normally identical. Of course, the angular disposition of both guy supports may also differ depending on the direction of the forces acting on the boom structure. The foot ends of both guy supports may be connected to the topside of the boom structure at a common area, or may be offset to one another. It is also conceivable to connect the foot end of the guy supports with the boom structure in the transition zone (i.e., the transition area) between topside and respective sidewall. As an alternative, there is also the option to arrange the foot end of at least one of the guy supports upon a girder which extends transversely to the longitudinal axis of the boom structure and projects beyond the boom structure.
Through the provision of a guy support according to the present invention, the portion of the guying force, effective in lateral direction, can be gradually and continuously modified in dependence on the angular disposition of the guy support. In the event, two guy supports are arranged offset to one another, both parallel guy supports act as super lift operation in a same manner as the conventional guy truss, when the boom structure is in the one extreme disposition, i.e. vertical disposition. At an angular position of <90° to>0° for both guy supports, the effective tautening force is split into a component super lift operation and a component lateral guying. In the other extreme position, i.e. horizontal disposition, both guy supports realize a reinforcement in both lateral directions.
The free head end of each guy support can be selectively connected via a first tension member (i.e., a first tension sub-arrangement) with the substructure, the superstructure, the foot region of the boom structure, the fixed or separately guided counterweight, or the bottom in the direction of the boom structure, and via a further tension member (i.e., a second tension sub-arrangement) with a selected area of the boom structure in the direction of its head. The respectively desired angular disposition of the guy supports may be adjusted step-by-step or continuously by swinging the guy supports, so that an asymmetric angular disposition is also possible. Thus, when a lateral force is applied on one side, the respective guy support is inclined progressively in the direction of lateral guying whereas the other guy support remains in a central position.
As the distance of the tension members from the boom structure has also an impact on the desired reinforcement, it is proposed to change the length of the guy supports in steps or continuously. The tension members may be a guy rope or a guy rod, and may be arranged with or without prestress. When prestressed at a degree that can be re-adjusted, the tension means is operatively connected with a tensioning mechanism. Suitably, the tensioning mechanism is a winch or a piston and cylinder unit. However, it is also possible, to exploit the angular disposition and/or change in length of the guy supports as tensioning mechanism. The tensioning mechanism may be selectively mounted to the guy supports, to the boom structure, to the superstructure or substructure, or to the counterweight.
According to another feature of the present invention, the guy supports are mounted to the main boom in the area of the boom base, in particular in the forward region between the hinged attachment of the luffing cylinder and the forward bearing on the boom base. Each guy support is suitably connected to a piston and cylinder unit which is mounted to the boom base, for continuous adjustment of the guy supports.
According to another feature of the present invention, the guy support includes two poles between which the winch may be positioned.
A telescopic crane according to the present invention may be further complemented by a fixed or luffing fly jib in the form of a latticed mast. Guy supports in accordance of the present invention may also be mounted to this type of jib.
A lateral guying is especially effective when the crane is provided with a measuring device, e.g. a load cell, for detecting a lateral deformation of the boom structure. When the deformation exceeds a predetermined admissible value, the tension member connected to the guying is activated for tautening the guying. The extent of lateral deformation can be registered directly or indirectly via crane parameters, for example, the rope tension, the rope length and the rope extension. However, forces acting upon the boom structure may be used for determination the degree of lateral deformation, such as side winds, exposure to sunlight and temperature of the boom structure.
The above and other objects, features and advantages of the present invention will be more readily apparent upon reading the following description of preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:
a is a principal illustration of a first embodiment of a telescopic crane according to the present invention, illustrating the arrangement of a guy support which is inclined with respect to the luffing plane;
b is a 90° rotated disposition thereof;
c is a perspective illustration thereof;
a to 3d are principal illustrations of a third embodiment of a telescopic crane according to the present invention, illustrating variations of an arrangement of two inclined guy supports terminating in separate foot ends;
a is a front view of an exemplified telescopic crane embodying the principals of the present invention with two inclined guy supports;
b is a side view thereof;
a–7c show various exemplified illustrations of telescopic cranes embodying the principles of the present invention; and
Throughout all the Figures, same or corresponding elements are generally indicated by same reference numerals.
Turning now to the drawing, and in particular to
In accordance with the present invention, the guy support 2 is inclined with respect to the luffing plane at an angle of α>0. As shown by broken lines, the guy support 2 may also be inclined to the other side. The guy support 2 has a free end 5 which is guyed by means of tension members 6, 7, preferably guy ropes. Although not shown in detail, the tension members 6, 7 are connected at a fixed point on the boom structure, or a tensioning mechanism such as a piston and cylinder unit, or a winch. Tautening of the tension members 6, 7 may, however, also be realized without use of a tensioning mechanism by arranging the tension members 6, 7 at a smaller or greater angel α and then further inclining the guy support 2. As an alternative, it is also possible to make the guy support 2 of telescopic configuration to effectuate a tautening through change in length.
As shown in
Turning now to
a to 3d show principal illustrations of a third embodiment of a telescopic crane according to the present invention, illustrating variations of an arrangement of two inclined guy supports 2.1, 2.2 terminating in separate foot ends 8.1, 8.2, respectively. In
A special case is illustrated in
Referring now to
As the guy supports 2.1, 2.2 are of an identical construction, the following description refers only to the guy support 2.1. However, it will be understood by persons skilled in the art that a description of one of the guy supports 2.1, 2.2 is equally applicable to the other one of the guy supports 2.1, 2.2. The guy support 2.1 includes two poles 13 which extend substantially parallel in the lower section and slightly converge in the area of the upper section. Interconnection of both poles 13 is realized by crossbars 14. The inner one of the poles 18 is provided at its foot end with a hinge 24. The outer one of the poles 13 bears upon the upper portion of the sidewall 9 of the boom base 1 when the guy supports 2.1 occupies their greatest inclination. This respective point of attack on the sidewall 9 is suitable reinforced by sheet metal 26. A winch 27 is rigidly positioned between the poles 13 in the lower area of the guy support 2.1. A guy rope 29 is secured on one end via a rope-end fitting or thimble 31 to the top region of the guy support 2.1 and is guided from there in the direction to a point of reversal (not shown), arranged at the boom tip, and back to a deflector sheave 30 disposed in the top area of the guy support 2.1. From there, the guy rope 29 runs to the winch 27. Positioned on the backside in the top area of the guy support 2.1 is a guy rod 32 for providing a rear safety mechanism for the guy support 2.1.
As described above, the superstructure 15 is swingable so that both guy supports 2.1, 2.2 can be deposited parallel to the topside 3 of the base boom 1 for transport of the telescopic crane. To raise again the guy supports 2.1, 2.2, each of the guy supports 2.1, 2.2 is provided as set-up aid with a piston and cylinder unit 28 (only the piston and cylinder unit 28 of guy support 2.1 is shown here) which has one end hinged to the sidewall 25 and another end hinged to a central region of the pertaining guy support.
As shown in
a–7c show various exemplified illustrations of telescopic cranes embodying the principles of the present invention. In each of these embodiments, the guy supports 2.1 and 2.2 may be pivotally attached to a boom base and/or to an extension thereof (e.g., a telescopic section 42, a fixed/rigid fly jib, a luffing fly jib, etc.).
b shows a schematic illustration of the telescopic boom crane 40 provided with a rigid fly jib, generally designated by reference numeral 49 to form a tower-like latticed extension of the boom crane 40. The fly jib 49 is mounted to the head 48 of the innermost one of the telescope sections 42.
c shows a schematic illustration of a telescopic boom crane, generally designated by reference numeral 50 and including a plurality of telescope sections 52 and a mast 51. The boom crane 50 is extended by a luffing fly jib, generally designated by reference numeral 52 to form a tower-like latticed extension of the boom crane 50. The luffing jib 52 has at least one, suitably two, slewed supports 53 which are mounted to the head 54 of an innermost one of the telescope sections 52.
d shows an illustration of a telescopic boom crane 40, providing guy supports 2.1 and 2.2 pivoting on an extension. As shown, the guy supports 2.1 and 2.2 are pivoting on the fly jib 49, which is mounted to the innermost one of the telescopic sections 42.
The boom structure 105 comprises the boom base 103 and a plurality of telescope sections 106, 107, 108, 109 and 110. The telescope section 106 is received in the boom base 103 and is respectively displaceable between a retracted and an extended position. The telescope section 107 is received in the telescope section 106 and is respectively displaceable between a retracted and an extended position. The telescope section 108 is received in the telescope section 107 and is respectively displaceable between a retracted and an extended position. The telescope section 109 is received in the telescope section 108 and is respectively displaceable between a retracted and an extended position. The telescope section 110 is received in the telescope section 109 and is respectively displaceable between a retracted and an extended position. In other words, the telescope section 110 is the innermost one of the telescope sections 106–110. The telescope section 110 is provided with a boom head 111 for guiding a rope 112 to which a load 113 can be attached. The telescope section 109 is provided with a collar 114.
Reference numeral 115 designates a hydraulic cylinder for lifting and lowering the boom structure 105 along the luffing plane. The luffing plane can be defined by three points, namely a first point at the base 120 of the boom structure 105, a second point at the boom head 111 and a third point, namely a center of gravity of the load 113. The triangle described by these three points is indicated with the dotted line 121 in
The telescopic crane 100 is provided with two guy supports 130 and 131, which are mounted to the base boom 103 of the boom structure 105. As may be taken from
Each of the guy supports 130 and 131 is attached to the boom base 103 via a joint. The guy support 130 is attached to the boom base 103 via a joint 135 and the guy support 131 is attached to the boom base 103 via a joint 136. The joints 135 and 136 are constructed such that they allow a pivotal movement around the joints 135 and 136 boom structure 105, such that an inclination of each of the guy supports 130 and 131 by be independently varied with respect to the luffing plane. It has to be noted that the guy supports 130 and 131 may be connected by means of a cross-strut such that only a coordinated movement of both guy supports 130 and 131 is possible. This cross-strut may also be telescopic, i.e. allow for an extension and retraction. The joints or hinges 135 and 136 may directly be connected to the boom base 103 or may be mounted to a frame (not shown in
Preferably, the guy supports 130 and 131 including or excluding the joints 135 and 136 may be detachable from the boom base 103.
As shown in
Between the collar 114 of the telescope section 109 and the distal end of the guy support 131, there is provided a tension means 139. Between the distal end of the guy support 131 and a stabilizer foot 140 of a plurality of stabilizer feet 140 of the substructure, there is provided another tension means 141. Preferably, the tension means 139 and 141 may be realized with one and the same rope.
Instead of being attached to the substructure 101, the tension means 138 may also be attached to one of the boom base 103, the superstructure 102, the stabilizer foot 140 and the ground. Instead of being attached to the stabilizer foot 140, the tensioning means 141 may be attached to the boom base 103, to the superstructure 102, to the substructure 101 and to the ground.
Between the guy support 130 and the boom base 103, there is provided a stabilizer leg 150. Between the guy support 130 and the boom base 103 there is provided another support leg 151. Preferably, the support legs 150 and 151 are attached to the boom base 103 and to the respective one of the guy supports 130 and 131 via suitable joints. Also, the support legs 150 and 151 may be provided with telescope means, allowing a lengthening and shortening of a length of the support legs 150 and 151 to thereby accomplish that the guy supports 130 and 131 are folded to the boom base 103 for a transport.
Due to the joints 135 and 136, the guy supports 130 and 131 can be inclined with respect to the luffing plane. Such inclination can be adapted. Preferably, during operation of the telescopic crane, an inclination of the guy supports 130 and 131 can be selected such that a lateral load acting on the boom structure 105 is partially or entirely received by the guying, comprising the guy supports 130 and 131 and the tensioning means 137, 138, 139 and 141.
In a variant of the exemplary embodiment of the telescopic crane 100 and the guying device according to the exemplary embodiment shown in
The guying shown in
Furthermore, the arrangement of the guy supports according to the present invention may fulfill a double function, namely in one position they serve for a normal super-lift operation and in another operating position they provide for a combination of super-lift operation and lateral guying. During the normal super-lift operation, the guy supports according to the present invention are arranged in the luffing plane or arranged parallel to the luffing plane. In the combination of super-lift operation and lateral guying, the guy supports are arranged with an inclination with respect to the luffing plane. This inclination may, for example, be 45°, such that forces acting laterally to the luffing plane and forces acting parallel to the luffing plane can be dealt with. Due to this, for example, when the boom structure is erected such that it is in a steep inclination, for example as shown in
The inclination of the guy supports 130 and 131 may be suitably adjusted between a position without an inclination where the guy supports 130 and 131 are in the plane of the luffing plane, i.e. parallel to the luffing plane and the other extreme position, where the guy supports are inclined with an angle of 90° to the luffing plane and where there is an angle of 180° between the two guy supports 130 and 131.
According to a variant of the exemplary embodiment shown in
While the invention has been illustrated and described as embodied in a telescopic crane, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Number | Date | Country | Kind |
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199 305 374 | Jun 1999 | DE | national |
This is a continuation-in-part of prior filed copending U.S. patent application No. 09/605,403, filed Jun. 28, 2000 now U.S. Pat. No. 6,550,624, which claims the priority of German Patent Application, Serial No. 199 305 37.4, filed Jun. 28, 1999.
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Number | Date | Country | |
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20040040926 A1 | Mar 2004 | US |
Number | Date | Country | |
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Parent | 09605403 | Jun 2000 | US |
Child | 10400193 | US |