EP0021171B1 - Double-linked crane jib system - Google Patents

Description

The invention relates to a double link crane boom system according to the preamble of claim 1.

Such a double link crane boom system is known from FIG. 3 of DE-C 602 311, according to which an exactly horizontal load path is sought. With regard to the size of the adjustment range of the deflection point, there are no demands in this publication; it can rather be seen from the drawings that a modest approach of the deflection point to the first articulation axis was sufficient.

In the known embodiment, the retaining link is subject to bending loads in that a support of a curved elongated hole is attached to the second retaining arm, into which a pin which corresponds to the fifth horizontal articulation axis and which attaches to the retaining link engages; the executives acting between the elongated hole and the pin exert a bending load on the retaining link at a point between the second horizontal articulation axis and the third horizontal articulation axis.

The invention has for its object to meet the requirements for achieving a small, minimal radius, a large, maximum radius and an approximately horizontal load path at the same time in a generic double-link crane boom system with a given size of the structural parts and to relieve the restraint arm from bending forces.

The measures according to the characterizing part of claim 1 serve to solve this problem.

It has been found that, in the configuration according to the invention, the tasks are fulfilled in accordance with the requirements, in such a way that the trajectories of the deflecting shaft connect tangentially to one another at the transition from the first adjustment range to the second adjustment range.

The decoupling of the first restraining arm when the stretched position between the traction link and the coupling device occurs can be carried out automatically without the need for external intervention in the system. The first restraining arm need not be permanently rigidly connected to the load arm. It is conceivable that the first retaining arm is articulated to the load arm in or near the second hinge axis and is supported on the load arm in a rotationally fixed manner by the second retaining arm in the first adjustment range of the system. The second retaining arm is permanently connected to the load arm in a rotationally fixed manner, but this does not require that the second retaining arm and the load arm are connected to one another, for example by a welded or screw connection. Rather, the second restraint arm and the load arm can also be connected to one another in an articulated manner, for example in the second articulation axis, the rotationally fixed connection between the second restraint arm and the load arm being able to be established by a permanently effective bracing, because the requirement for a rotationally fixed connection of the second Retaining arm and the load arm is already fulfilled when the second restraining arm is fixed in a rotational direction in a rotational direction.

A possible connection between the first restraining arm and the tension link, which causes the first restraint arm to be automatically decoupled from the tension link when the stretched position between the tension link and the tension coupling occurs, is based on an elongated hole connection between the first retention arm and the tension link.

• Fig. 1 eine erfindungsgemäße Ausführungsform eines Doppellenker-Kranauslegersystems in der Stellung minimaler Ausladung;
• Fig. 2 das Doppellenker-Kranauslegersystem gemäß Fig. 1 in einer Stellung mittlerer Ausladung, und zwar derjenigen Stellung, in der die Zugkoppel gerade in Strecklage zu dem Zuglenker getreten ist, so daß diese Stellung die Grenzstellung zwischen einem ersten Verstellbereich des Systems und einem zweiten Verstellbereich des Systems bildet und
• Fig. 3 das Doppellenker-Kranauslegersystem nach den Fig. 1 und 2 in einer Stellung maximaler Ausladung.

The accompanying figures explain the invention; it represents:

• Figure 1 shows an embodiment of a double link crane boom system according to the invention in the position of minimal radius.
• Fig. 2, the double link crane boom system according to FIG. 1 in a position of middle radius, namely the position in which the drawbar has just entered the drawbar in the extended position, so that this position is the limit position between a first adjustment range of the system and a second Adjustment range of the system forms and
• Fig. 3 shows the double link crane boom system according to FIGS. 1 and 2 in a position of maximum radius.

In Fig. 1 the parts 11 Oa, 110b, 11 Oc are components of a rigid support, i.e. the parts 11 Oa, 11 Ob, 11 Oc are unchangeable in their relative position under normal circumstances. At 11 oc, a basic link 112 is articulated on the carrier 110 about a first horizontal hinge axis 114. The basic link 112 is pressure-resistant. At the tip of the basic link 112, a load arm 120 of a head link 116 is articulated about a second horizontal hinge axis 118. A double-acting hydraulic piston-cylinder unit 132 is arranged between the basic link 112 and the carrier 110, specifically a point 11 above the carrier 110, which serves to change the inclination of the basic link 112 and thus to adjust the entire system. The position of minimal projection of the system can be seen in FIG. 1. In this position, a cable deflection point on the load arm 120, which is denoted by 134, has a minimal distance amin in front of an axis 136 which is shown in dash-dot lines and which, for example, symbolizes a tower axis in the case of a tower crane.

The course of the hoisting rope is selected so that when the wind is at a standstill, the height of the load hook or other load lifting device is not changed when the deflection point 134 passes through the line between the two extreme positions, in which one of the throat a _mln and in the other the projection a _maxll (Fig. 3).

In the second articulation axis 118, two restraining arms are articulated on the basic link 112, a first restraining arm 150 and a second restraining arm 152. The second restraining arm 152 is connected in a rotationally fixed manner to the load arm 120 by an anchoring, not shown but symbolized by the bow 154, so that the second restraining arm 152 cannot be moved relative to the load arm 120 in the sense of enlarging the arc 154. The first restraining arm 150 is connected to the second restraining arm 152 by a pull coupling 156, which extends between the third horizontal articulation axis 126 and a fifth horizontal articulation axis 164, so that in the adjustment range shown in FIG. 1, the first restraining arm 150 on the second Retaining arm 152 and thus ultimately rigidly fixed to the load arm 120, in the sense that the arc 166 shown in broken lines cannot be increased in angle. One can speak of a restraint device 150, 152, 156 associated with the head link 116, which is held by the tension link 128 articulated on the carrier 110 in a fourth horizontal articulated axis 130 at 110. The third horizontal hinge axis 126 is formed between the pull link 128 and the pull coupling 156. An elongated hole guide 160 is arranged on the first restraining arm 150 and wraps around an articulated head 162 on the third horizontal articulated axis 126 connecting the drawbar coupling 156 and the drawbar 128.

In the position of the crane boom system shown in FIG. 1, the first restraining arm 150 is subjected to pressure by a force K acting on the deflection point 134. The articulated head 162 is always in the lower end of the elongated hole 60 in FIG. 1. The system spanned by the first restraining arm 150, the second restraining arm 152, the guying 154 and the pulling coupling 156 behaves as a rigid disk; the movement of the system takes place in the first joint axis 114, the second joint axis 118, the third joint axis 126 and the fourth joint axis 130. The deflection point 134 for the hoisting rope passes through the double-dotted, approximately horizontal load path 138 up to the radius amax _{l '}

In Fig. 2 the system is in the position which corresponds to the projection a _maxI . In this position according to FIG. 3, the pulling coupling 156 has just entered the pulling arm 128 in the extended position. If the adjustment system is now further adjusted from the position according to FIG. 2 in the direction of the position according to FIG. 3, the pull coupling 156 remains in the extended position with respect to the pull link 128. The system now behaves as if a single pull element 128 + 156 would attack directly on the second restraining arm 152, which is still fixed invariably with respect to the load arm 120 via the arc 154. The boom system now behaves similarly to the system shown in FIG. 1 with the difference that the movement now takes place in the first articulated axis 114, the second articulated axis 118, the fifth articulated axis 164 and the fourth articulated axis 130. The first restraining arm 150 is no longer loaded. The elongated hole 160 can move freely relative to the joint head 162, as is shown from the difference between FIGS. 2 and 3.

• Bis zur Stellung der Fig. 2 kann das durch die Gelenkachsen 118, 126 und 164, sowie den Umlenkpunkt 134 aufgespannte Polygon als eine starre Scheibe betrachtet werden. Diese starre Scheibe hat als momentanen Drehpol in der Stellung gemäß Fig. 2 den Punkt P, der sich aus den gedachten Verlängerungen des Grundlenkers 112 und des Zuglenkers 128 ergibt. Nach Erreichen der Position gemäß Fig. 2 bis zum Übergang in die Position gemäß Fig. 3 kann man das von den Gelenkachsen 118 und 164, sowie dem Umlenkpunkt 134 aufgespannte Polygon als starre Scheibe auffassen, deren momentaner Drehpol wiederum durch die gedachten Verlängerungen des Grundlenkers 112 und des Zuglenkers 128 definiert ist. Der Umlenkpunkt 134 dreht sich also bei Annäherung des Systems von der Stellung gemäß Fig. 1 kommend an die Stellung der Fig. 2 um den gleichen momentanen Drehpol P wie bei Beginn des Übergangs des Systems von der Stellung gemäß Fig. 2 in die Stellung gemäß Fig. 3. Dies ist gleichbedeutend mit der Aussage, daß die Wegabschnitte 138 und 138' tangential aneinander anschließen.

By choosing the location for the fifth articulation axis 164, it can be achieved that the path of the deflection point 134, which is designated 138 'beyond the projection a _maxI and is drawn with three-dot-dash lines, remains essentially horizontal, that is to say only slight, acceptable deviations from the horizontal Own path. In this way, a usable _throat a _{maxII is} achieved. The path section 138 'of the deflection 134 adjoins the path section 138 tangentially with a transition tangent T, as can be seen from FIG. 2. The correctness of this determination can be demonstrated as follows:

• Up to the position of FIG. 2, the polygon spanned by the hinge axes 118, 126 and 164 and the deflection point 134 can be regarded as a rigid disk. 2, point P, which results from the imaginary extensions of the basic control arm 112 and the pull control arm 128. After reaching the position according to FIG. 2 until the transition to the position according to FIG. 3, the polygon spanned by the articulation axes 118 and 164 and the deflection point 134 can be regarded as a rigid disk, the current pivot of which in turn is due to the imaginary extensions of the basic link 112 and the link 128 is defined. The deflection point 134 thus rotates when the system approaches from the position shown in FIG. 1 to the position shown in FIG. 2 by the same momentary rotation pole P as when the system began to change from the position shown in FIG. 2 to the position shown in FIG 3. This is equivalent to the statement that the path sections 138 and 138 'connect tangentially to one another.

The fifth hinge axis 164 can be positioned in relation to the other hinge axes 114, 118, 126 and 130 in such a way that the approximately horizontal connection of the curve section 138 'to the curve section 138 is ensured.

Claims (2)

1. Double-linked crane jib system with a substantially horizontal load path, comprising a main link (112) acting as a compression member and pivotally mounted on a support (110) about a first horizontal pivot (114), a top link (116) pivotally mounted on the main link (112) about a second horizontal pivot (118), with a load arm (120) having a guide point (134) for guiding a hoisting cable within the suspension span, a retaining device (150, 152, 156) and further a retaining link (128) which at a fourth horizontal pivot (130) is connected to the support (110) and engages the retaining device (150, 152, 156) at a point of application (162) which varies in relation to the load arm (120) during the displacement of the jib radius, the retaining device (150, 152, 156) comprising a first retaining arm (150), which is articulatedly connected about a third horizontal pivot (126) to the retaining link (128) and at or near the second pivot (118) to the load arm (120), and a second retaining arm (152) which is connected to the load arm (120) in a manner precluding relative rotation and at a fifth horizontal pivot (164) to the retaining link (128) at or near the third pivot (162), characterised in that the retaining link comprises a tension link (128), in that the second retaining arm (152) is connected at the fifth horizontal pivot (1 64) via a tension coupling link (156) forming apart of the retaining device (150, 152, 156) to the tension link (128) via the third pivot, and in that, when the tension link (128) and the tension coupling link (156) reach an extended position, the first retaining arm (150) can be uncoupled from its connection to the tension link (128) - transition from a first displacement zone (138) to a second displacement zone (138') - and can be coupled to the tension link (128) when this extended position is no longer present - transition from the second displacement zone (138') into the first displacement zone (138) -, the first retaining arm (150) being supported in the first displacement zone (138) by the second retaining arm (152) and the tension coupling link (156) being supported in relation to the load arm (120) in a manner precluding relative rotation.

2. Double-linked crane jib system according to Claim 1, characterised in that the first retaining arm (150) is connected to the tension link (128) by a slot connection (160, 162).

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