JPH0237827Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a jib crane that suspends a load from the tip of an inclined jib.

(Prior Art) Conventionally, for example, the structure of the load hanging part of a jib crane such as a truck crane is as shown in Figs. 4 and 5.
As shown in the figure, a plurality of hanging sheaves 21 are lined up at the tip of the jib 1 and rotatably supported by a spindle 22, and a hook block 23 has a plurality of hook sheaves 24 arranged directly below each lifting sheave 21, and a hook sheave pin is attached to the hook block 23. 25, and a hook base 6a of a hook 6 disposed below the hook sheave 24 is supported by a hook pin 26, which is widely used. In the figure, 27 is a frame of a hook block.

(Problem to be Solved by the Invention) However, when using the above-mentioned conventional jib crane having a load hanging part inside a building, even if the rope R is cut off and the hook block 23 is hoisted up to the highest position, the hook sheave pin 25 and the hook pin 26 are As shown in FIG. 4, a large unhoistable distance S remains, and the effective lift is reduced. Generally, when installing machinery inside a building, the effective lifting height of the hook must be as large as possible due to ceiling height restrictions. It was not suitable as such.

This invention is intended to solve the above-mentioned conventional problems, and aims to provide a jib crane that can increase the effective lifting height of the load hanging section.

(Means for Solving the Problems) In order to achieve the above object, the jib crane of this invention has a plurality of hanging sheaves pivotally supported at the tip of the jib, and a plurality of hook sheaves pivotally supported on the hook block. In a jib crane having a load hanging part around which a hoisting rope is wound, a hook sheave is arranged on both sides of the hook base, and the hook sheave is rotatably supported by a hook pin that supports the hook base. The suspension sheave directly above is a wide sheave, and the rope is wound around one hook sheave adjacent to the hook base, and the rope is wound through the wide sheave to the other hook sheave adjacent to the hook base.

(Function) In the jib crane of this invention, the hook pin supports the hook base and also serves as a support shaft that rotatably supports the hook sheave.
The distance L between the conventional hook sheave pin and the hook pin shown in FIG. 4 becomes zero, and the hook block can be hoisted to a higher place by this L, increasing the effective lifting height. In addition, the rope exiting one hook sheave adjacent to the hook base is routed through the wide sheave pivoted at the tip of the jib to the other hook sheave adjacent to the hook base, and at this time, the rope is passed through the body of the wide sheave. Because the rope is wound in a straight winding manner, even near the highest hoisting position when the hook block is close to the hanging sheave, the deviation angle α (fleet angle) of the rope going in and out of the hook sheave is
(see figure) is small, so the rope can be smoothly wound and unwound without coming off each sheave.

(Embodiment) An embodiment of this invention will be described below with reference to FIGS. 1 to 3.

In the figure, reference numeral 1 denotes a telescopically tiltable jib of a truck crane, which is telescopically and tiltably driven by a known drive mechanism (not shown). 2 is a guide sheave, which is a rope (wire rope) driven by a winder (not shown).
3 is a hanging sheave rotatably supported by a support shaft 4 at the tip of the jib 1. The hanging sheaves 3 include narrow hanging sheaves 3a, 3b, and 3d around which one rope is wound,
It consists of a wide sheave 3c. On the other hand, 5 is a hook block, and the hook 6 is constructed by attaching both ends of a trunnion pin-type hook pin 7 that supports the hook base 6a in a swingable and rotatable manner to the frame 8, and rotatably supports the hook sheave 9 on the hook pin 7. . The hook sheave 9 is a narrow hook sheave 9a~
9d are arranged in two pieces on each side of the hook base 6a, and the hook sheave 9a is located directly below the hanging sheave 3a, the hook sheave 9b is located directly below the hanging sheave 3b, and the hook sheave 9d is located directly below the hanging sheave 3d. They are arranged as follows. Further, the width W of the wide sheave 3c is approximately equal to the sum of the width of the hook base 6a and the width of the hook sheave 9c, and the hook sheave 9C is disposed directly below the end of the wide sheave 3c. Then, the rope R is wound around the hook sheave 9 as shown in the figure.
The rope R exiting from b passes over a wide sheave 3c and is wrapped around a hook sheave 9c. In addition, the rope R
One end is wound up by the winding machine as mentioned above,
The other end is fixed to the jib 1.

In the truck crane having the load lifting section 10 configured as described above, the hook block 5 can be hoisted together with the hook sheave 9 to a position where the upper end of the hook base 6a approaches the wide sheave 3c, and the hook sheave pin 25 and the hook pin 26 in FIG. The effective lifting height of the hook 6 increases by an amount corresponding to the distance L between the axes. For example, in the case of a 25 ton hook with a rope diameter of 16 mm, this L dimension is approximately 400 to 500 mm.
Therefore, when lifting work is performed in a building with limited ceiling height, the benefit of increasing the effective lifting height by this amount L is large. Furthermore, the rope R extending from the hook sheave 9b to the hanging sheave 9c via the wide sheave 3c is wound around the body of the wide sheave 3c in a helical line shape, so that even if the hook block 5 reaches the uppermost position, the hanging sheave 9b The deviation angle α (fleet angle) of the rope R of 9c and 9c is small, so the rope R is
It can be smoothly wound and rewound without coming off. If a narrow hanging sheave 15 shown by a chain line in FIG. 2 is placed on the hook center line instead of the wide sheave 3c, the deviation angle α increases and the rope R is moved away from each sheave 15, 9b, 9c. It comes off and is of no practical use.

In the above embodiment, the width W of the wide sheave 3c is expanded to just above the hook sheave 9c, but as shown by the chain line in FIG.
Wide sheave 1 having a width W′ approximately equal to the width of a
1 may be used and no hook sheave is provided directly above the hook sheave 9c.

This invention is not limited to the above embodiment. For example, in the above embodiment, four hanging sheaves 3 and four hook sheaves 9 were used, but an appropriate number of these sheaves can be used, such as two each or six. You may use more than one. Further, as the hook 6, a single-hanging type hook may be used. Furthermore, this invention can be applied to various jib cranes other than truck cranes, such as wheel cranes.

(Effects of the invention) As explained above, according to this invention, a practically useful jib crane is provided, which can increase the effective lifting height of the load hanging part and is particularly suitable for work inside a building.

[Brief explanation of the drawing]

Fig. 1 is a front view of a load hanging section of a truck crane showing an embodiment of this invention, Fig. 2 is a side view taken along arrow A-A in Fig. 1, and Fig. 3 is a side view taken from arrow B-- in Fig. 2. B is a plan view, FIG. 4 is a front view of a load hanging section of a conventional truck crane, and FIG. 5 is a side view taken along the line C--C in FIG. 4. 1... Jib, 3... Hanging sheave, 3c... Wide sheave, 4... Support shaft, 5... Hook block, 6... Hook, 6a... Hook base, 7... Hook pin, 8... Frame, 9... Hook sheave, 10... Load hanging part, 1
1...Wide sieve.

Claims (1)

[Scope of utility model registration request] Multiple hanging sheaves pivoted at the tip of the jib,
In a jib crane that has a load hanging part in which a hoisting rope is wound around a plurality of hook sheaves pivotally supported on a hook block, the hook sheaves are arranged on both sides of the hook base, and the hook sheaves are suspended by hook pins that support the hook base. The hanging sheave directly above the hook base is a wide sheave, and a rope wound around one hook sheave adjacent to the hook base passes through the wide sheave and is connected to the other hook sheave adjacent to the hook base. A jib crane characterized by being wrapped around a hook sheave.