JPS6113508Y2 - - Google Patents

Description

[Detailed description of the invention] When transporting a mobile crane from one work site to another, the counterweight is removed and the top half of the jib is removed, and the mobile crane is placed in a transport position and transported on a trailer, etc. Therefore, transporting a mobile crane always involves the work of installing and removing a counterweight.

The present invention relates to a mobile crane with a counterweight mounting and removal function.

Here, the mobile crane will be briefly described with reference to FIG. 1. A jib 2 is provided on the front side of the main body 1 so that it can be raised and lowered, and a gantry arm 3 that can be raised and lowered is provided on the rear side. The midway portion of the jib 2 and the main body 1, and the tip of the arm 3 and the main body 1 are connected by an extendable jib limit stopper 4 and an extendable sub-arm 5, respectively. A hook 6 is suspended from the tip of the jib 2 and is raised and lowered by a hoisting and lowering device (not shown), and a rope 8 connected to a hoisting device 7 is connected to the arm 5.
The rope 8 is hung around the tip and the tip of the rope 8 is connected to the vicinity of the tip of the jib 2 so that the jib 2 can rise and fall. The jib limit stopper 4 is the jib 2
This is to prevent the structure from rising above a predetermined angle or falling down. When transporting such a mobile crane, the upper half 9 of the jib is removed, the gantry arm 3 is laid down, the rope 8 is connected to the bracket 10 provided at the upper end of the base half 9' of the jib, and the counterweight 11 is removed. Take a posture.

Next, we will discuss the conventional counterweight installation and removal work. There are many possible ways to install and remove the counterweight, but
Here, the work performed by raising and lowering the gantry arm 3, which is closely related to the present invention, will be described.

As mentioned above, the gantry arm 3 necessary for the raising and lowering movement of the jib 2 can be raised and lowered, and since this arm 3 has sufficient strength, the counterweight 11 can be attached using the raising and lowering movement of the arm 3. Can be removed.

As a first conventional example, an extendable sub-arm 5
Alternatively, a hydraulic cylinder is provided in parallel with the sub-arm 5, and the gantry arm 3 is raised and lowered by driving the hydraulic cylinder, and the counterweight 11 is mounted and removed. In this example, a dedicated hydraulic cylinder must be provided for the above-mentioned work, and the hydraulic cylinder itself is expensive, and the manufacturing cost has increased due to the piping that must be attached.

As a second conventional example, the jib 2 is assembled as shown in FIG. 7 is actuated to wind in and unwind the rope 8. Due to this winding and unwinding operation, the distance between the tip of the jib 2 and the tip of the gantry arm 3 changes, and the gantry arm 3 eventually rises and falls. It is something that moves. In this example, the counterweight 11 cannot be installed or removed until after the jib 2 has been assembled, and the removed upper half 9 of the jib is transported by another truck. It would be extremely inconvenient if the transport of the upper half 9 of the jib was delayed due to poor performance.

Furthermore, both of the above-mentioned examples do not have a device for connecting the gantry arm 3 and the counterweight 11, requiring a complicated connection operation using a chain block or the like.

The present invention was developed to eliminate such drawbacks, and it is possible to attach and detach the hoisting rope that is hung from the end of the gantry arm that can be hoisted to the middle of the jib, and to create an extendable and retractable rope that limits the hoisting angle of the jib. The jib limit stopper is installed close to the jib's hoisting rope connection position, and the jib limit stopper can be fixed in the jib hoisting state, and the gantry arm and counterweight can be disconnected by a chain or the like. This is a characteristic feature.

Embodiments of the present invention will be described below based on FIGS. 2 and 3.

2 and 3 show the counterweight 11 in a raised or lowered state, respectively, and in both figures, the same components as in FIG. 1 are designated by the same reference numerals.

Attach the end of the extensible jib limit stopper 4 on the jib 2 side close to the connecting position of the rope 8 (for example, to the bracket 10 for connecting the rope 8), and further attach the end of the extensible jib limit stopper 4 to the required position of the jib limit stopper 4. A device (for example, a stopper pin 12 passing through the jib limit stopper 4 in the radial direction) for restraining expansion and contraction in the length is provided. Also, gantry arm 3
A hook 13 is provided at the tip of the gantry arm 3 and the upper surface of the counterweight 11, and the gantry arm 3 and the counterweight 11 can be connected and separated by a chain 14 or the like. Further, the counterweight 11 can be fixed to the main body 1 with bolts 15.

Since the present invention is constructed as described above, the counterweight can be installed and removed by performing the following operations.

First, when removing the counterweight 11, the expansion and contraction of the stopper 4 is restrained by the stopper pin 12, and the rope 8 is secured to the bracket 10.
2, connect the gantry arm 3 and counterweight 11 with the chain 14, and then remove the bolt 15 (the state shown in FIG. 2). If the rope 8 is rewound by the undulating device 7, the counterweight 11 can be removed and lowered (the state shown in FIG. 3).

In the above operation, since the expansion and contraction movement of the jib limit stopper 4 is restrained, the movement of the jib 2 can be restrained, and the mounting position of the stopper 4 on the jib side is located close to the connecting position of the rope 8. Therefore, when the counterweight 11 is suspended, no excessive moment is applied to the jib 2.

When attaching the counterweight 11, the above procedure can be reversed, and in this case, it can be done directly from the transportation position.

Of course, instead of the chain 14, a rope may be used to connect the hooks 13, 13.

As described above, according to the present invention, there is no need to provide a hydraulic cylinder for attaching and detaching the counterweight, it is easy to connect and disconnect the counterweight and the gantry arm, and it is also possible to attach and detach the counterweight in any condition. Demonstrates excellent effects.

[Brief explanation of the drawing]

Figure 1 is an overall view of a conventional mobile crane, Figure 2
3 and 3 are explanatory diagrams of the mobile crane according to the present invention, FIG. 2 is a diagram showing the counterweight being lifted up, and FIG. 3 is a diagram showing the counterweight being lowered. 2 is a jib, 3 is a gantry arm, 4 is a jib limit stopper, 8 is a rope, 11 is a counterweight, and 13 is a hook.

Claims (1)

[Scope of utility model registration request] The hoisting rope that is hung around the tip of the gantry arm that can be hoisted can be detached from the middle of the jib, and the extendable jib limit stopper that limits the hoisting angle of the jib is installed close to the jib's hoisting rope connection point. A mobile crane characterized in that the jib limit stopper can be fixed in the jib up-and-down state, and the gantry arm and counterweight can be disconnected by a chain or the like.