JPS6055439B2 - Mounting structure of extension pulley on telescopic boom - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention has at least three booms that are mutually telescoping, an extension pulley is attached to the tip of the intermediate boom,
One end of the extension wire rope that is wrapped around the extension pulley is fixed to the base boom, and the other end is fixed to the base end of the front boom, so that the intermediate boom is connected to the base boom. In a telescopic boom configured such that the front boom is extended relative to the intermediate boom by simply extending the
, , Li C'd↓FJ- This relates to a new structure.

FIG. 1 diagrammatically shows a three-stage telescopic boom of this type, which comprises an intermediate boom 1, a base boom 2 that telescopically supports the intermediate boom 1, and a base boom 2 that telescopically supports the intermediate boom 1. A front boom 3 that is extendably supported by the intermediate boom 1, an extension pulley 4 provided at the tip of the intermediate boom 1, and an extension pulley 4 that is wrapped around the extension pulley 4 and one end of which is attached to the base boom. an extension wire rope 5 fixed to a distal end portion A of the boom 2 and whose other end is fixed to a proximal end portion B of the forward boom 3; and a hydraulic cylinder for extending and contracting the intermediate boom 1 with respect to the base boom 2. (shown in the figure) etc., and when the intermediate boom 1 is extended with respect to the base boom 2, the forward boom 3 is also extended with respect to the intermediate boom 1 at the same time by the wire rope 5. Such telescoping booms themselves are commonly used and known in hydraulic telescoping boom cranes.

Incidentally, in this type of telescopic boom, the wire rope for extension tends to have a larger diameter along with the trend of larger cranes.In this case, for the safety of the rope 5, the diameter d of the rope and the diameter D of the pulley 4 are The ratio (D/d) needs to be higher than a certain ratio, and the larger it is, the more the rope 5
The fatigue strength of is increased, which is preferable.

Here, if the pulley 4 is made larger while adopting the structure in which the shaft center of the pulley 4 is located higher than the main body of the intermediate boom 1 as before, the wire rope 6 for crane hoisting and stretching will be placed higher up accordingly. It becomes necessary to stretch the sheep block 7 to the tip of the front boom 3, which requires making the sheep block 7 larger and therefore heavier.
This is undesirable because it results in a reduction in the lifting capacity of the crane within the limited overturning moment of the crane. This invention was made in view of the above background, and the shaft center of the extension pulley is not located above the telescopic boom as in the past, but is located in the middle of the telescopic boom, thereby increasing the amount by which the extension pulley protrudes upward. In this case, the axis of the extension pulley would be located on the side plates of the front boom, but in the present invention, the mounting structure of the extension pulley is By devising this, it was possible to increase the boom width of the forward boom, that is, the dimension between its both side plates, and thus to increase the rigidity of the forward boom as much as possible. In the mounting structure of the present invention, one extension pulley is arranged at the tip of the intermediate boom and on both sides of the front boom in a plan view perpendicular to the axis of the telescoping boom.
The axes of the extension pulleys are in a V-shaped relationship, and each extension pulley has a U-shaped cross section with wall plates inside and outside, and is covered with a bracket made of a copper plate continuous to the intermediate boom. Ori,
Each extension pulley is pivotally supported by a headed shaft that penetrates the inner and outer wall plates of the bracket from the outer wall plate side, and the headed shaft is prevented from coming out by a pin located inside the inner wall of the bracket. It is characterized by this.

Below are the second to second examples of the present invention adopted in a four-stage telescopic boom.
This will be explained in detail using Figure 4. In the diagram, 1, 2, 3, 4, 7 are the first
Same numbers in the figure. Corresponds to.

In this example, a basic boom 8 having a hydraulic cylinder is further provided at the base of the base boom 2 to form a four-stage telescopic boom. Further, 9 is an auxiliary winding pulley for an auxiliary winding wire lobe provided in front of the sheave block 7. The mounting structure of the extension pulley will be explained with reference to FIG. 4, which is projected onto a plane along the line ■-■ in FIG. 2, that is, perpendicular to the axis of the telescopic boom. In the figure, 7 is a sheave block installed in front of the front boom 3. It is made up of side plates 7a and 7b formed by extending both side plates of the front boom 3 in the z direction. A main winding pulley 10 and an auxiliary winding pulley 11 are supported above, and a main winding pulley group 12 is supported below, and the main winding wire lobe 6 wound around the main winding drum (not shown) is supported by the pulleys 10 and 12. The auxiliary winding wire lobe, which is wound around the pulley group of the main winding hook (not shown) and the auxiliary winding drum, is also wound around the pulleys 11 and 9. The above structure is a normal one. 4 in Fig. 4 is an extension pulley, and only one is shown in the figure;
The pulleys 4 are arranged in pairs on both sides with the front boom 3 in between, and their shaft centers are located in the middle of the front boom 3, and both shaft centers are located as shown in the figure. They are slanted and have an H-shaped relationship with each other.

Reference numeral 13 denotes a bracket provided at the front end of the intermediate boom 1. The bracket 13 has a U-shaped cross section and is composed of an outer wall plate 13a, an inner wall plate 13b, and a ceiling wall plate 13c.
b is substantially on the same plane as the outer wall plate 1a of the intermediate boom 1, and the outer wall plate 13a projects outward as can be seen from FIG.

16 is a headed shaft for a pulley having a head 16a on one side and a pin hole 16b for a retaining pin on the other side, and the headed shaft 16 is connected to the outer wall plate 13a of the bracket 13, the boss of the pulley 4, It passes through the inner wall plate 13b of the bracket 13.

Reference numeral 14 denotes a retaining pin disposed inside the inner wall plate 13b of the bracket 13. The lower end of the retaining pin 14 is fitted into the pin hole 16b of the headed shaft 16, while the upper end extends above the bracket 13. The plate fixed to the upper end can be fixed to the top wall plate 13c of the bracket 13 with bolts 15 while being superimposed on the top wall plate 13c. In the figure, 1d indicates a part of the bottom wall plate constituting the intermediate boom 1, W1 indicates the width between the inner wall plates 1a of the intermediate boom 1, and W2 indicates the width between the outer wall plates of the front boom 3. Reference numeral 5 denotes a telescopic wire lobe, one end of which extends outward from the tip of the proximal boom 2 and is fixed to the bracket A, and the other end extends from a metal fitting (not shown) protruding outward from the proximal end of the proximal boom 3. ), and is wound around a pulley 4 in the middle.

In the above structure, intermediate boom 1 is used for base boom 2.
If the front boom 3 is extended, the front boom 3 extends with respect to the intermediate boom 1, as in the previous case.

The assembly order will be explained below.

As mentioned above, the width between the outer surfaces of both outer wall plates of the front boom 3 is W2, but that part is attached to the outer surface of the proximal end of both outer wall plates along the inner surface of the outer wall plate 1a of the intermediate boom 1. There is a protrusion, usually called a side pad, that guides the forward boom 3. Therefore, it is impossible to insert the front boom 3 into the intermediate boom 1 when the pulley 4 etc. are assembled as shown in Figure 4. be. Then, pull out the pin 1 shaft 16 and pulley 4.
With the front boom 3 removed, one end of the wire lobe 5 is fixed to the base end of the front boom 3, and the front boom 3 is inserted into the intermediate boom 1. Next, the pulley 4 is placed in a predetermined position, and the headed shaft 16 is moved outward. The pin 14 is inserted from above, the pin 14 is then fixed with the bolt 15, and the other end of the lobe 5 is fixed to the bracket A to complete the assembly. Since the present invention is constructed as described above, firstly, the shaft for the pulley 4 is a headed shaft 16, which is arranged at an angle, and the pin 14 method is used to prevent the pulley from slipping out. Even if a part of the lower end of the pulley 4 is made within the width W1, the tip of the headed shaft 16 can be placed as far outward as possible, and therefore the width W2 of the front boom 3 can be made as large as possible and has high rigidity. Second, the inner and outer wall plates 13b and 13a of the bracket 13 are connected to the headed shaft 1.
6 between the head 16a and the pin 14, there is no risk that both wall plates 13a, 13b will open despite the overall U-shaped cross section. Since the pin 14 is used to prevent the pin 14 from coming off, it is extremely easy to attach the pin 14 even though it is a so-called bag part, and there are many advantages such as ease of assembly.

[Brief explanation of the drawing]

Fig. 1 is a diagrammatic conceptual diagram of a three-stage telescopic boom, Figs. 2 to 4 are a front view and a plan view of an embodiment of the extension pulley mounting structure according to the present invention, and Figs. FIG.

Claims (1)

[Claims] 1 having at least three mutually telescoping booms;
An extension pulley is attached to the tip of the intermediate boom, and one end of the extension wire rope wrapped around the extension pulley is fixed to the base boom, and the other end is fixed to the base end of the front boom. In a telescopic boom configured such that the front boom is extended relative to the intermediate boom only by extending the intermediate boom relative to the base boom, the intermediate boom is One extension pulley is arranged at the tip of the boom and on both sides of the front boom, and the axes of both extension pulleys are in a V-shaped relationship, and each extension pulley has an inner and outer extension pulley. It is covered with a steel plate bracket that has a U-shaped cross section with a wall plate and is continuous with the intermediate boom, and each extension pulley is a headed type that penetrates the inner and outer wall plates of the bracket from the outer wall plate side. 1. A mounting structure for an extension pulley in a telescopic boom, characterized in that the headed shaft is pivotally supported by a shaft, and the headed shaft is prevented from being removed by a pin located inside the inner wall of the bracket.