JPH10218570A - Grantry type rope locking device for walking crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rope locking device from adversely affecting the life of the rope of a walking crane, by turning the portal stanchion of the crane being moved in posture to keep away from the rope. SOLUTION: When a box boom extends, an n-stage boom 4n and an (n-1)- stage boom 4n-1 separate from each other to separate a portal stanchion 11 from a rod 12. The stanchion 11 thus separated from the rod 12 that normally forces it down automatically rises to its upright position defined by a stopper 17 by means of the turning force of a torsion spring. When the box boom telescopes, on the other hand, the n-stage boom 4n and the (n-1)-stage boom 4n-1 move toward each other to bring the stanchion 11 into contact with the rod 12. Upon the telescopic motion of the box boom to the limit, the rod 12 forces the stanchion 11 down. The stanchion 11 is thus turned down in posture to keep away from the rod 12 while the crane is moved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portal crane locking device for a mobile crane which prevents the rope from falling off from the back of the boom of the mobile crane.

[0002]

2. Description of the Related Art Conventionally, as a mobile crane in which this kind of rope retaining device is used, for example, there is an all terrain crane shown in FIG.

[0003] In this mobile crane, a carrier 2 travels by the operation of a worker in an operator's cab 1. Carrier 2
The upper revolving superstructure 3 is mounted on the
Is provided with a box boom 4 that can be raised and lowered. The box boom 4 is composed of multi-stage booms, and the booms of each stage extend and contract in a telescopic manner. Further, a boom head 5 is provided at the tip of the box boom 4, and the boom head 5 is provided with sheaves 6 and 7. A winding wire rope 8 is wound around each of the sheaves 6 and 7, and a hook 9 is connected to the winding wire rope 8.

[0004] In such an all terrain crane, the box boom 4 is raised at the time of operation, and the boom of each stage is extended. Then, a load is loaded on the hook 9 suspended at the tip of the box boom 4. The load hung on the hook 9
The wire rope 8 is lifted or lowered by being wound up or extended.

In order to prevent the wire rope 8 stretched on the back surface of the box boom 4 from dropping off from the back surface of the box boom 4 when the wire rope 8 is rolled up and unwound, the portal column 10 shown in FIG. Is attached to the back of the boom 4. 4, the same parts as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. When the wire rope 8 falls off, the dropped wire rope 8 gets caught on the projection on the side surface of the boom 4, and the boom 4 and the wire rope 8 are damaged. A rope detent device prevents such damage.
The gate-type support 10 has a gate-like shape in the shape of a katakana "U", and a wire rope 8
Is enclosed in the gate to prevent falling off.

[0006]

However, the height of the gate of the portal post 10 is set so that the portal post 10 contacts the wire rope 8 and does not refract the wire rope 8 hung on the back surface of the boom 4. , Very high. Therefore, when moving the crane, it is necessary to lower the portal column 10. In the prior art, the rope detachment prevention device falls down by its own weight in the state shown in FIG. Since the wire rope 8 is stretched during the operation of the crane, the portal column 10 is erected by this tension. Therefore, the wire rope 8 is rubbed against the portal column 10 when the wire rope 8 is extended or wound up during the crane operation. On the other hand, since the wire rope 8 is loosened during non-work, the portal column 10 falls down. As described above, since the conventional rope detachment prevention device is always in contact with the wire rope 8, the rope detachment prevention device and the wire rope 8 rub against each other, which adversely affects the life of the wire rope 8.

[0007] For this reason, there is also conceivable a rope detachment prevention device in which the portal column 10 is not always kept in contact with the wire rope 8 and the portal column 10 is manually raised and held only during crane work. However, if the configuration is used in which the rope stopper device is manually raised during the crane operation, it takes time and labor to prepare for the operation, and it is not possible to expedite the work by spending labor and time.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a portal type of a telescopic boom which surrounds a rope hung along the back of a telescopic boom of a mobile crane. In a portal rope stopper device for a crane comprising a portal column provided on the back of a boom at a predetermined stage so as to be able to be raised and lowered, a column raising means for urging the portal column to a side where the column type column is raised, and the column raising means is erected by the column raising means. A stopper for stopping the gate-type post at a predetermined position, and a stopper provided on the back of the boom of a step adjacent to the predetermined-stage boom provided with the gate-type post, and coming into contact with the portal-type post standing up according to the retracting operation of the telescopic boom. And a column lowering means for pressing down the gate type column.

In such a configuration, when the telescopic boom is extended, a distance is created between the boom of the step provided with the gate-type support and the boom of the adjacent step provided with the support-down means. Move away from the means of strut support. When the gate-type strut moves away from the strut-down means, the gate-shaped strut which has been pushed down by the strut-down means automatically rises to a position defined by the stopper by the strut-raising means.

When the telescopic boom shrinks, the distance between the boom of the step provided with the column-shaped column and the boom of the adjacent step provided with the column-down means is reduced, and the column-type column is provided with the column-down means. Abut As the telescopic boom further contracts, the portal post is pushed down by the strut-down means.

[0011] The portal strut pushed down by the strut strut means maintains the pushed down posture as long as the telescopic boom does not expand or contract.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment in which a portal type rope retaining device for a mobile crane according to the present invention is applied to the above-described all terrain crane will be described.

FIG. 1 is a side view showing a portal rope retaining device according to the present embodiment. In this figure, the same or corresponding parts as those in FIG. 4 are denoted by the same reference numerals.

The box boom 4 is provided with the upper revolving unit 3 described above.
The state shown in the figure shows a state in which the box boom 4 is contracted. On the back of the tip of the _n- th stage boom 4 _n constituting the box boom 4,
Each end of the portal column 11 having a U-shape is rotatably supported. The portal 11 surrounds the hoisting wire rope 8 hung along the back of the box boom 4 in a portal configuration.

Further, (n− _n) adjacent to the _n- th stage boom 4 _n
1) A rod 12 is fixedly provided on the back surface of the distal end of the stage boom 4 _n-1 . The rod 12 constitutes a pillar lowering means for abutting on the upright portal 11 and pushing down the portal 11 in accordance with the contraction operation of the box boom 4.

FIG. 2 (a) is a partially enlarged side view of the portal rope retaining device shown in FIG. 1, and FIG. 2 (b) is a plan view of FIG. 1 (a). In addition, the same figure shows the gate type support 11
Is shown, only one end is shown, and the gate-shaped support 11 is configured such that the other end exists at a position symmetrical to this.

Both ends of the column-shaped support 11 are supported by the _n- th stage boom 4 _n by pins 13, and the portal-type support 11 pivots around these pins 13 and freely undulates. Each pin 13 has a torsion spring 14 inserted therein. One end of the torsion spring 14 is locked to the _n- th stage boom 4 _n , and the other end is locked to the end of the portal column 11. The torsion spring 14 is a spring that constitutes a column raising means that urges the portal column 11 toward the side where the column type column 11 is raised.

One rod 12 is composed of a pair of rod members, and one end of each rod member is (n-
1) It is fixed to the stage boom 4 _n-1 . A roller 15 is rotatably supported by a pin 16 at the other end of each rod member. In the illustrated state, the roller 15 is in contact with the base of the portal column 11. When the portal 11 moves with the expansion and contraction of the _n-th boom 4 _n , the roller 15 rotates and comes into contact with the base of the portal 11 with low resistance.

When the torsion spring 14 raises the column-shaped support 11, the stopper 17 protruding near the end of the column-shaped support 11 forms a wall 18 of the _n- th stage boom 4 _n .
To stop the gate-type column 11 in the upright position as described later.

In such a configuration, when the box boom 4 is extended, the n- _th boom 4 _{n on} which the portal column 11 is provided and the adjacent (n-1) -th boom 4 on which the rod 12 is provided. _As shown in the side view of FIG. 3A, a distance is created between _n-1 and _n-1, and the portal 11 is separated from the rod 12. When the portal 11 is separated from the rod 12, the portal 11 that has been pushed down by the rod 11 automatically rises to the illustrated upright position defined by the stopper 17 by the rotational force of the torsion spring 14. Since the torsion spring 14 is designed so that the rotational force of the spring remains when the portal column 11 is raised at this position, the portal column 11 is fixed at this upright position.

When the box boom 4 is contracted, the n- _th boom 4 _n provided with the gate-shaped column 11 and the adjacent (n-1) -th boom 4 _n-1 provided with the rod 12 are provided. Is reduced, and the portal column 11 abuts on the rod 12. When the box boom 4 is further contracted and retracted, the portal column 11 is pushed down by the rod 12 as shown in FIG. At this time, the column-shaped support 11 and the rod 12 are contacted with low resistance by the roller 15, and the portal-type support 11 is pressed down smoothly.

In this embodiment, the crane operation is performed in a state where the box boom 4 is extended and the portal column 11 stands up, and the wire rope 8 does not contact the portal column 11 during the operation. Further, the gate-shaped column 11 pushed down by the rod 12 maintains the pushed-down posture unless the box boom 4 is extended. Therefore, it is possible to lower the portal column 11 to a position that does not contact the wire rope 8 when the crane is moved. Therefore, the conventional concern that the gate-shaped support strung on the wire rope 8 rubs against the wire rope 8 and adversely affects the life of the wire rope 8 is solved.

Further, the operation of raising and lowering the rope stopper device can be automatically performed by extending and retracting the box boom 4. Therefore, unlike the rope stopper device according to the present embodiment, which is different from the conventional rope stopper device that manually raises the portal column during crane work, the labor and time for handling the rope stopper device are reduced, and the work is reduced. Proceed quickly.

In the above embodiment, the present invention is applied to an all-terrain crane. However, the present invention can be applied to other cranes as well. Further, in the above-described embodiment, the spring constituting the column raising means has been described as the torsion spring 14, but it may be composed of another spring. In each of these cases, the same effect as in the above embodiment is achieved.

[0025]

As described above, according to the present invention, when the telescopic boom of the mobile crane is extended, the portal column is automatically raised to the position determined by the stopper by the column raising means. Also, when the telescopic boom is retracted, the portal post is automatically pushed down by the strut-down means. For this reason, the posture of the gate-type wire rope stopper device can be easily controlled by extending and retracting the boom, and the operation can be performed quickly.

Further, the portal-type strut pushed down by the strut strutting means maintains the pushed-down posture as long as the telescopic boom does not expand or contract. Therefore, when the crane is moved, the portal column is tilted so that it does not contact the rope.
The rope release device will not adversely affect the life of the rope.

[Brief description of the drawings]

FIG. 1 is a side view of a tip end portion of a box boom equipped with a portal rope detachment prevention device for a mobile crane according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view showing a side surface and a plane of the portal type rope retaining device shown in FIG. 1;

FIG. 3 is a side view showing a change in the posture of the portal rope detachment prevention device according to the embodiment.

FIG. 4 is a side view showing a general all terrain crane.

FIG. 5 is a side view showing a portal-type rope stopper device of a conventional mobile crane.

[Explanation of symbols]

Reference Signs List 4 ... Box boom 4 _n ... n-th boom 4 _n-1 ... (n-1) -th boom 11 ... Gate-shaped strut 12 ... Rod (post strut means) 13, 16 ... Pin 14 ... Torsion spring (strut erecting means) 15) Roller 17 ... Stopper 18 ... Wall of _n- th stage boom 4n

Claims (3)

[Claims] 1. A movable crane comprising a portal-type column provided around a boom at a predetermined stage of the telescopic boom so as to be able to move up and down, surrounding a rope hung along the back of the telescopic boom of the movable crane. In the portal-type rope retaining device, a column raising means for urging the portal-type column to a side where the column-type column is raised,
A stopper for stopping the portal-type column standing up by the column-raising means at a predetermined position, and a stopper provided on the back surface of a boom adjacent to the predetermined-stage boom provided with the column-type column in accordance with the contraction operation of the telescopic boom. A column-type rope retaining device for a mobile crane, comprising a column-lowering means for abutting the portal-type column and pushing down the portal-type column. 2. An end of the portal type column is rotatably supported on the rear surface of the distal end of an n-th stage boom, and the column raising means has one end at the n-th stage boom and the other end at the gate. The stopper comprises a projection of the portal type column which abuts on a part of the n-th stage boom in the upright position, and the column supporting means comprises a (n-1) th stage. 2. The portal type rope retaining device for a mobile crane according to claim 1, wherein the device comprises a rod fixedly provided on the back surface of the end of the boom. 3. The device according to claim 2, wherein the rod contacts the portal column via a roller.