JPH0130759B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-stage boom telescoping device.

In general, cranes and the like employ multi-stage booms, and it is preferable that the multi-stage booms operate sequentially in a predetermined order whether they are extended or retracted. To achieve this, it is necessary to devise a hydraulic circuit, use electrical means such as a limit switch, or use a cam. However, as the number of booms increases, the structure for sequentially extending and retracting them becomes quite complex and expensive.

The present invention has been made in view of the above circumstances,
a second boom within the first boom, a third boom within the second boom, a fourth boom within the third boom,
It is an extension/retraction device for multi-stage booms that are slidably inserted into each other, and the second and third booms are sequentially extended and retracted relative to the first boom using two hydraulic cylinders and a cam device, and the fourth The purpose of the present invention is to provide a boom that is simple in structure, inexpensive, and capable of reliably extending and retracting by using pulleys and cables to extend and retract simultaneously with the third boom.

Embodiments of the present invention will be described below based on the drawings. A first boom 1, a second boom 2 that is slidably inserted into the first boom 1 and is extendable and retractable with respect to the first boom 1. , a third member slidably inserted into the second boom 2 and extendable and retractable with respect to the second boom 2;
A multi-stage boom is constituted by the boom 3 and a fourth boom 4 that is slidably inserted into the third boom 3 and is extendable and retractable with respect to the third boom 3.

The tip of the piston rod 6 of the first hydraulic cylinder 5 is pivotally supported on the inner base of the first boom 1.
The tip of the cylinder body 7 is pivotally supported on the inner base of the second boom 2 together with the tip of the piston rod 9 of the second hydraulic cylinder 8. The cylinder body 10 of the second hydraulic cylinder 8 is provided with pulleys 11 and 12 at its base and tip, respectively, and the tip of the body 10 is pivotally supported by the inner base of the third boom 3. There is.

Note that the base of the main body 7 of the first hydraulic cylinder 5 and the second
The base of the main body 10 of the hydraulic cylinder 8 is the connecting member 13
It is supported by

On the other hand, a cable 14 whose one end is fixed to the base of the fourth boom 4 is hung around the above-mentioned pulley 11, and the other end is fixed to the base of the second boom 2. Also,
A cable 15 having one end fixed to the tip of the fourth boom 4 is suspended around the pulley 12, and the other end is fixed to the tip of the second boom 2.

Next, the hydraulic circuit of the present invention will be explained with reference to FIG.
The pressure oil supplied to the oil passage 16 from a hydraulic pump (not shown) reaches the piston side oil chamber 20 of the first hydraulic cylinder 5, and then passes through the pipe line 2.
1. The oil is supplied to the piston side oil chamber 22 of the second hydraulic cylinder 8 via the oil passage 18. In addition, the oil passage 17
The pressure oil supplied to the piston rod reaches the piston rod side oil chamber 23 of the first hydraulic cylinder 5, and then passes through the pipe line 24,
The oil is supplied to the piston rod side oil chamber 25 of the second hydraulic cylinder 8 through the oil passage 19.

The pressure oil supplied to the oil passage 16 or 17 as described above is supplied to the extension side oil chamber or contraction side oil chamber of each of the first hydraulic cylinder 5 and the second hydraulic cylinder 8.

By the way, a pair of guides 26 and 26' are fixed to the upper wall of the base of the second boom 2, passing through the upper wall.
Shafts 27, 27' are inserted into the guides 26, 26' with their upper and lower ends extending slightly beyond the guides 26, 26'. And this axis 27,2
7', one at its bottom, the other at its top,
Locking arms 29, 2 with locking portions 28, 28'
9' is fixed, and this locking arm 29, 2
On the shafts 27, 27' on the opposite side of 9', there are abutment arms 3
0,30' are fixed, and these locking arms 29,
29' and abutment arms 30, 30' for the cam device C.
is configured.

On the other hand, stoppers 31, 31' are fixed to appropriate positions on the inner and outer surfaces of the upper wall of the second boom 2, and springs 32, 32' ( The clockwise rotation of the locking arms 29, 29' and the abutment arms 30, 30', which are biased by the guides 26, 26' (FIG. 4), is restricted. By the way, the third
At the base of the outer surface of the upper wall of the boom 3 and the inner tip of the upper wall of the first boom 1, there are locking rollers 33 that can engage with the locking portions 28, 28' of the locking arms 29, 29' described above.
33' is fixed to the tip of the inner surface of the upper wall of the first boom 1 and the base of the outer surface of the upper wall of the third boom 3.
Abutment rollers 34, 34' that can come into contact with the aforesaid abutment arms 30, 30' are provided. Therefore, when the multistage boom is in the contracted state, the abutting roller 34' is in contact with the abutting arm 30', and the abutting arm 30' and the locking arm 29' are moved counterclockwise against the spring 32'. In addition to rotating in the direction,
The locking roller 33 engages with the locking portion 28 of the locking arm 29 . Therefore, the first boom 1 and the second
The lashing with the boom 2 is released, and the second boom 2 and the third boom 3 are lashed.

Next, to explain the operation of the present invention, when the multi-stage boom is in the contracted state as shown in FIG.
A hydraulic pump (not shown) is operated to supply pressure oil to oil path 1.
6, both hydraulic cylinders 5 and 8 try to extend. However, in the second boom 2 and the third boom 3, the locking roller 33 is
Since it is engaged with the locking portion 28 of No. 9, it is secured (FIG. 4), and first the first hydraulic cylinder 5 is extended. Therefore, the second boom 2 extends more than the first boom 1. When the second boom 2 is fully extended,
The abutment roller 34 disposed on the inner surface of the upper wall of the tip of the first boom 1 comes into contact with the abutment arm 30 and rotates the abutment arm 30 counterclockwise against the spring 32, so that the abutment roller 34 is locked. At the same time that the locking portion 28 of the arm 29 is released from the locking roller 33, the first boom 1
A locking roller 33' disposed on the inner surface of the upper wall of the tip faces the locking portion 28' of the locking arm 29'. Therefore, the binding between the second boom 2 and the third boom 3 is released, pressure oil is supplied through the pipe line 21 and the oil line 18, the second hydraulic cylinder 8 is extended, and the third boom 3 is expanded. It will extend from the second boom 2.

Due to the extension of the third boom 3 and the movement of the abutting roller 34', the locking arm 29' and the abutting arm 30' rotate clockwise due to the biasing force of the spring 32' to lock them. portion 28' engages the locking roller 33', and the second boom 2 and the first boom 1
(Figure 5). Furthermore, as the third boom 3 extends, tensile force is applied to the cable 14.
At the same time, the fourth boom 4, whose other end is fixed, is attached to the third boom.
Extend from boom 3. When the second hydraulic cylinder 8 is fully extended, the multistage boom reaches its fully extended state.

When the multi-stage boom is at its maximum extension, the first
Since the boom 1 and the second boom 2 are tied together, and the second boom 2 and the third boom 3 are unlocked, when pressure oil is supplied to the oil passage 17, the pressure oil is transferred to the first hydraulic pressure. Although the contraction side oil chambers 23 and 25 of the cylinder 5 and the second hydraulic cylinder 8 are reached, the second hydraulic cylinder 8 contracts first.

When the second hydraulic cylinder 8 retracts, the third boom 3 retracts into the second boom 2, and at the same time, a tensile force acts on the cable 15 whose one end is fixed to the fourth boom 4, causing the fourth boom 4 to shrink at the same time. When the third boom 3 is maximally contracted into the second boom 2, the abutment roller 34' comes into contact with the abutment arm 30' and rotates counterclockwise, contrary to the above description, and the locking arm 29' is rotated counterclockwise. At the same time that the locking portion 28' is released from the locking roller 33', the locking roller 33 faces the locking portion 28. Therefore, the binding between the first boom 1 and the second boom 2 is released, the first hydraulic cylinder 5 is retracted, and the second boom 2 is retracted into the first boom 1. By reducing the second boom 2, the cam device C
is disengaged from the abutting roller 34 and the locking roller 33', and as a result, the abutting arm 30 is released from the spring 32.
The second boom 2 and the third boom 3 are locked together because the second boom 2 and the third boom 3 are rotated clockwise and the locking portion 28 engages the locking roller 33.

As described above, in the present invention, a cam device having a locking arm and an abutment arm is disposed at the base of the second boom, and is placed at appropriate positions on the first boom side and the third boom side corresponding to each arm of the cam device. A matching roller and a locking roller are arranged, and a pulley pivotally supported at the tip and base of the third boom is suspended to connect the second boom and the fourth boom.
A pair of cables are fixed between the booms, and hydraulic cylinders are installed between the first and second booms and between the second and third booms, so that the second and third booms can be extended and retracted in sequence. By doing so, the third boom and the fourth boom can be simultaneously extended and retracted, and the multi-stage boom can be extended and retracted in as little time as possible and with a small boom cross section. Furthermore, compared to a system in which all four stages of booms are extended and retracted sequentially, the structure is simpler and cheaper.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional side view schematically showing the entire multi-stage boom, and FIG.
The figure is a hydraulic circuit diagram, Figures 3a and 3b are enlarged plan views and side views showing the cam device installed on the second boom, Figure 4 is a partial plan view showing the second boom in a contracted state, and Figure 5 The figure is a partial plan view showing the second boom in an extended state. 1...First boom, 2...Second boom, 3...
Third boom, 4... Fourth boom, 5, 8... Hydraulic cylinder, 14, 15... Cable, 29, 29'...
... Locking arm, 30, 30' ... Collision arm, 3
3, 33'... Locking roller, 34, 34'... Collision roller, C... Cam device.

Claims (1)

[Claims] 1 A multi-stage boom is constructed by slidably inserting a second boom into the first boom, a third boom into the second boom, and a fourth boom into the third boom. The first and second hydraulic cylinders are arranged between the first boom and the second boom and between the second boom and the third boom, respectively, and a cam device having a pair of arms is installed at the base of the second boom. However, the locking roller 3 of one arm 29 is located at the base of the third boom.
3, and the other arm 2 at the tip of the first boom.
9' locking rollers 33' are respectively provided,
At the tip of the first boom, there is an abutting roller 34 that releases the engagement with the locking roller 33 of one arm 29.
Also, at the base of the third boom, there is an abutting roller 3 for releasing the engagement with the roller 33' of the other arm 29'.
A multi-stage boom extension and retraction device in which a pair of cables are fixed between the second boom and the fourth boom by hanging pulleys arranged at the ends of the base of the third boom. . 2. The body tip of the first hydraulic cylinder and the second hydraulic cylinder.
2. The multi-stage boom telescoping device according to claim 1, wherein the piston rod tip of the hydraulic cylinder is integrally and pivotally connected to the second boom base.