JPH0253357B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a bending device for a multi-joint boom for a cargo handling machine or a concrete distributor, which is constructed by combining a plurality of booms by rotatably connecting the ends of adjacent booms. The present inventors have already developed a cargo handling device having an articulated boom 20 as shown in FIG. In this cargo handling device, a revolving body 24 is attached to a mast 21 so that it can be raised and lowered by a lifting device 22 having a lift cylinder 25, and can be rotated around the mast 21 via a turning ring 23. It is made by attaching an articulated boom 20. The multi-joint booms 20 include a plurality of booms (in this example, three booms: a boom 1' at the base end, a boom 1 at the middle end, and a boom 2 at the tip end).
, the bending cylinder 10 and links 11 and 1 are connected around the pin 3 between the ends of adjacent booms.
2, the boom 1' at the base end is connected to a frame 26 fixed on the revolving body 24 by a luffing cylinder 27 centered around a pin 3'.
The rotating body 24 is mounted so as to be able to rise and fall freely.
The hoisting rope 29, which is repeatedly wound around the hoisting winch 28 installed above, is hung over a guide sheave 30 attached to the boom joint and tip, and a hanging device 31 is suspended from the boom tip. . This cargo handling device can extend and retract the multi-joint boom 20 in the horizontal direction, and when constructing a building etc., it is possible to take in and take out suspended loads through the side opening. In this way, there is no need to leave openings for hanging loads on the floor until the end, and work can be done even in bad weather such as rain or snow, which shortens the construction period and allows workers to There is no need to pull together the hanging tool 31 or the suspended load during loading and unloading, which can contribute to reducing labor and improving safety. Furthermore, by attaching a fresh concrete pumping pipe (concrete distributor) to the articulated boom 20 shown in FIG.
Mobility is improved, and there is no need to connect piping for pumping fresh concrete or disassemble it. FIG. 2 is a diagram showing the configuration of a bending device provided between adjacent booms in such a multi-joint boom 20, in which one ends of the links 11 and 12 are rotatably connected to the booms 1 and 2 by pins 32 and 33, respectively. The bending cylinder 10 has one end rotatably connected to the boom 1 by a pin 34, and the other end rotatably connected to the other ends of the links 11 and 12 by a common pin 35. Become. Such a structure is generally used because it allows for a wide rotation range. However, as will be explained in detail later, depending on the orientation of boom 1, even if the rotation angle α of boom 1 and boom 2 is the same,
The moment M around the joint point (pin 3) acts on the refraction cylinder 10 in both tension and compression directions,
If the range of the rotation angle α between the boom 1 and the boom 2 is wide, the geometrical shape of the joint will be unfavorable to receive the moment M near the maximum and minimum rotation angle α, and the refractive A large load acts on the cylinder 10, and the stroke also becomes long. As the stroke becomes longer, the buckling strength must be increased, so a longer cylinder 10 must be used. In view of the above-mentioned points, it is an object of the present invention to provide a bending device for a multi-joint boom that can be made smaller and lighter. To achieve this object, the present invention provides a multi-joint boom bending device in which a plurality of booms are combined by rotatably connecting the ends of adjacent booms, in which one end of the link is connected to the boom joint. The other ends of two or two sets of bending cylinders are rotatably connected to or near the center of rotation of the link, and one end of each of the adjacent booms is rotatably connected to the other end of the link. It is characterized by being rotatably connected. FIG. 3 is an embodiment of the present invention, and shows an example in which the present invention is applied to the multi-joint boom 20 shown in FIG. As shown in FIG. 3, in this embodiment, two refraction cylinders 6, 8 and one
The bending cylinders 6 and 8 are rotatably connected to the booms 1 and 2 by pins 7 and 9, respectively, and the link 4 has one end connected to the center of rotation of the boom joint, that is, the boom 1. , 2 are rotatably connected to a connecting pin 3, and the other end of the link 4 and each other end of the bending cylinders 6, 8 are rotatably connected to each other by a common pin 5. , which constitutes a refraction device. With such a configuration, when changing the rotation angle α between the boom 1 and the arm 2, the rotation angle range can be shared by the two bending cylinders 6 and 8. The stroke per cylinder of the book is small, so the two triangles formed between the cylinders 6, 8, the link 4, and the booms 1, 2 are not as flat as the conventional one, and therefore, The loads acting on the cylinders 6, 8 are also relatively stable over the entire range of movement. This will be explained using skeleton diagrams shown in FIGS. 4 to 9 while comparing it with the conventional example. The range of rotation angle α, which is a premise for comparison, is 60° to 240°.
Figures 4, 6 and 8 are of the present invention, Figures 5 and 7.
9 and 9 are conventional examples under the same conditions as the previous figure in each figure, and FIGS. 4 to 7 show the rotation angle α
is 60° and Figures 4 and 5 show the refraction cylinders 6, 8,
When a compressive force is applied to the refraction cylinders 6, 8, and 10, FIGS. 6 and 7 show that the rotation angle α is
This is a case where a compressive force is applied to the refraction cylinders 6, 8, and 10 at an angle of 240°. When the rotation angle α is the minimum angle of 60 degrees, the triangle formed by the cylinders 6 and 8, the link 4, and the booms 1 and 2 of the present invention shown in FIGS. The triangle formed by the cylinder 10, link 11, and boom 1 in the case of the conventional example shown in FIG. and link 11
A large force acts on the A similar trend is seen in the comparison between FIGS. 8 and 9. Figure 10 shows the cylinder acting force (t) in the range of rotation angle α = 60° to 240° when the moment around the joint point (pin 3) is ±5 t・m and the working oil pressure is 210 kg/cm ² . It is a diagram illustrating a comparison between the present invention and a conventional example with the maximum loads set to be the same.
It can be seen that the case according to the present invention is averaged over the entire range and is more stable than the case according to the conventional example. Particularly in the case of the conventional example, if the rotation angle α is even slightly less than 60°, the cylinder acting force becomes infinite, and it is virtually impossible to use the cylinder in this vicinity. The general specifications of the cylinder under the above conditions are as shown in the table below.

【table】

[Table] In the above table, the cylinder weight in the present invention is the total weight of two cylinders. As can be seen from the above table, according to the present invention, it is possible to use a small cylinder with a stroke that is about one-fourth that of the conventional example, and the total weight of the cylinder can be reduced to about one-third. In connection with this, the number and size of the links and the members surrounding the links are also reduced, so the weight is also significantly reduced. In the above embodiment, one cylinder 6, 8 is provided on each side of the link 4 of the boom joint part, but either one or both may be used in combination with two or more small diameter cylinders. It is also possible. Further, one end of the link 4 may be located not at the pin 3 but at a position near the pin 3 of the booms 1 and 2. Further, the connection points of each cylinder 6, 8 to the link 4 do not necessarily have to be the same. As described above, according to the present invention, since the boom joint portion is constituted by two (sets) of refraction cylinders having one end connected to each boom and the link connected as described above, the refraction The cylinder, the link, and the members surrounding these can be significantly reduced in size and weight. Therefore, when the present invention is applied to cargo handling equipment, concrete distributors, etc., the weight of the multi-jointed boom can be reduced, working capacity can be improved, manufacturing costs can be reduced, and energy savings can also be achieved. I can contribute.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a cargo handling device having an articulated boom using a conventional refraction device, Fig. 2 is a partially enlarged view of the refraction device in Fig. 1, and Fig. 3 is a partial enlarged view of the refraction device of the present invention. 4 to 9 are skeleton diagrams showing a comparison between the present invention and a conventional example at various boom postures and boom rotation angles, and FIG. 10 is a side view of a boom joint showing an embodiment. It is a graph showing a comparison of cylinder acting force in a dynamic angle range. 1, 2...Boom, 3, 5, 7, 9...Pin, 4...
Link, 6, 8...Refraction cylinder.

Claims (1)

[Claims] 1. In a multi-joint boom bending device that combines multiple booms by rotatably connecting the ends of adjacent booms, one end of the link can be rotated to or near the center of rotation of the boom joint. Two or two sets of bending cylinders which are freely connected and have one end rotatably connected to each of the adjacent booms, each other end of which is rotatably connected to the other end of the link. An articulated boom refraction device featuring: