JPS6354630B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a boom telescoping device for a multi-stage boom.

(Prior Art) Cranes and the like are generally equipped with a telescoping multi-stage boom, and a hydraulic cylinder is used for the telescoping operation.

By the way, in such a multi-stage boom,
If one hydraulic cylinder corresponds to one boom, an m-stage boom requires (m-1) hydraulic cylinders, and a large number of hydraulic cylinders must be installed in a small boom. Naturally, there was a problem that the degree of freedom in design was small.

For this reason, when extending and retracting the leading boom, the telescopic cylinder for extending and retracting the leading boom is abolished, and the telescopic cylinder of the second boom into which the leading boom is slidably inserted is used to extend and retract the leading boom. Are known.

However, in such conventional technology, since the second boom is in a floating state, the second boom may slide together with the first boom due to friction when the first boom is extended, and the multi-stage boom is in a depressed state. Sometimes this tendency is even more pronounced.

(Problems to be Solved by the Present Invention) The present invention has been made in view of the above points, and an object of the present invention is to reliably prevent simultaneous extension of the second boom due to friction when the first boom is extended. It is.

(Technical means for solving the problem) The present invention provides a continuous three-stage boom including a front boom, in which pin holes are formed in the front boom, second boom, and connecting member, while pin holes are formed in the second boom and the third boom. A locking portion is formed on the boom, and when the first boom is extended, the lashing pin is transferred from the pin hole to the locking portion, and the second boom is connected to the third boom.

(Embodiment) An embodiment of the present invention will be described below based on the drawings. Reference numeral 1 indicates the entire multi-stage boom, which is composed of three consecutive booms including a front boom.

That is, the multistage boom 1 includes a base boom 2, an intermediate boom 3 slidably inserted into the base boom 2, and a tip boom 4 slidably inserted into the intermediate boom 3. ing.

Reference numeral 5 denotes a hydraulic cylinder disposed within the multi-stage boom 1, the base end of which is pivotally supported by the base boom 2, and the rod 6
A connecting member 7 of an appropriate length is extended from the tip.

A pin hole 10 that matches the pin holes 8 and 9 formed at the ends of the intermediate boom 3 and the front boom 4 is bored at the tip of the connecting member 7, and the connection is usually made by inserting a lashing pin 11. The member 7 is connected to the front boom 4 and the intermediate boom 3.

On the other hand, a boom head 12 is fixed to the front boom 4, and the insertion holes drilled in each of the front boom 4 and the boom head 12 are aligned and secured with fixing bolts 13. .

Further, when the boom head 12 and the boom 4 are secured with the fixing bolts 13, the insertion holes 14 and 15 formed in both are made to match, and furthermore, these insertion holes 14 and 15 are , matches a pin hole 16 drilled in the connecting member 7, so that the securing pin 11 can be inserted therein.

By the way, as will be described later, in order to prevent simultaneous extension of the intermediate boom 3 when the front boom 4 is extended, a locking device 17 is provided on the base boom 2 and the intermediate boom 3.

This locking device 17 is connected to a pin hole 19 of a projecting piece 18 provided on the base boom 2 and a tip member 2 of the intermediate boom 3.
The pin hole 21 of No. 0 is aligned with the pin hole 21 of No. 0 so that the securing pin 11 can be inserted therein.

In addition, 22 is a stopper fixed to the tip of the front boom 4, and 23 is a pin hole drilled at the base of the front boom 4. When the front boom 4 is extended, the pin holes 10 and 8 of the connecting member 7 and the intermediate boom 3 are inserted. The securing pin 11 can be inserted by matching the position.

Further, 24 and 25 are guide pieces and parts attached to the connecting member 7.

Next, the operation of the present invention will be explained. When the multi-stage boom 1 is retracted, the securing pin 11 is normally connected to the connecting member 7.
, the pin hole 8 of the intermediate boom 3, and the pin hole 9 of the tip boom 4, thereby securing the three together.

Therefore, if a two-stage boom is required, by extending the hydraulic cylinder 5 in this state, the intermediate boom 3 can be moved relative to the base boom 2 while the front boom 4 is held in the contracted state within the intermediate boom 3. and expand,
After that, if the hydraulic cylinder 5 is reduced, the intermediate boom 3
is reduced to base boom 2.

On the other hand, when a three-stage boom is required, the lashing pin 11 is pulled out from the pin holes 10, 9, and 8, and the pin hole 19 of the projection piece 18 and the pin hole 20 of the tip member 20 are removed.
and fix the intermediate boom 3 to the base boom 2.

Thereafter, when the hydraulic cylinder 5 is extended, the connecting member 7 comes into contact with the stopper 22 to extend the front boom 4 with respect to the intermediate boom 3 (see FIG. 3a).

When the front boom 4 is fully extended, the hydraulic cylinder 5 is contracted, and only the hydraulic cylinder 5 is contracted while the front boom 4 is held in the extended state. When the hydraulic cylinder 5 is minimized, the pin hole 10 of the connecting member 7,
Since the pin hole 8 of the intermediate boom 3 and the pin hole 23 of the front boom 4 match, the lashing pin 11 inserted into the pin holes 19, 21 is pulled out and the pin hole 10,
8, 23 (see Figure 3b).

Therefore, since the front boom 4 is fixed in an extended state with respect to the intermediate boom 3, if the hydraulic cylinder 5 is then extended, the intermediate boom 3 will be extended further than the base boom 2 (see Figure 3c). .

When the crane work is completed, the hydraulic cylinder 5 is reduced, the intermediate boom 3 is stored in the base boom 2, and the lashing pins 11 are transferred to the pin holes 19 and 21.

Next, after extending the hydraulic cylinder 5 and bringing the connecting member 7 into contact with the stopper 22, the lashing pins 11 are transferred to the pin holes 16, 15, 14 and the hydraulic cylinder 5 is contracted. is stored in the intermediate boom 3. Thereafter, the lashing pins 11 are transferred to the pin holes 10, 9, and 8, and the vehicle assumes a running position.

In this example, the multi-stage boom consisted of a three-stage boom consisting of a base boom, an intermediate boom, and a front boom, but even if the multi-stage boom is four or more stages, three successive booms including the front boom are used. Applicable to booms.

(Effects of the Invention) As described above, in the present invention, since a single lashing pin is selectively inserted into the pin hole, the operation is ensured, and when the front boom is extended, the front boom is Simultaneous extension of the second boom, which is slidably inserted, can be reliably prevented.

[Brief explanation of drawings]

The drawings illustrate embodiments of the invention.
The figure is a longitudinal sectional view of the multistage boom, FIG. 2 is an exploded sectional view of the main parts of the boom, and FIGS. 3 a, b, and c are explanatory diagrams showing the extension procedure. 1...Multi-stage boom, 2...Basic boom (third boom),
3...middle boom (second boom), 4...first boom,
5... Hydraulic cylinder, 7... Connection member, 8, 9, 1
0, 14, 15, 16, 19, 21...pin hole, 1
1...Lashing pin.

Claims (1)

[Claims] 1. A multistage boom having at least a front boom, a second boom into which the front boom is slidably inserted, and a third boom into which the second boom is slidably inserted, one end of which is pivoted to the third boom. A hydraulic cylinder that is connected and provided with a connecting member at the other end, a stopper provided on the front boom, a pin hole formed to match the front boom, a second boom, and the connecting member, and the second boom. consisting of pin holes of the locking device formed to match the third boom, and a single lashing pin that can be selectively inserted into these pin holes,
The lashing pin is configured to be transferred to the pin hole of the locking device when the front boom is extended by bringing the connecting member into contact with the stopper and extending the hydraulic cylinder. Boom extension device in multi-stage boom.