JP2547808Y2 - Telescopic boom device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic boom device used for, for example, a crane truck.

[0002]

2. Description of the Related Art As this type of telescopic boom device, there is a telescopic boom device having a multi-stage telescopic boom device driven by a hydraulic cylinder installed therein.

In such a telescopic boom device, a distal end of a piston rod (hereinafter simply referred to as a rod) of a hydraulic cylinder is connected to a proximal end of a base boom, and a cylinder end of the hydraulic cylinder on the rod side is connected to an intermediate boom. And the telescopic boom device is driven to expand and contract by connecting to the base end of the telescopic boom.

[0004] When such a telescopic boom device is extended and a hanging load acts on the distal end side, the load acts on the hydraulic cylinder in the extended state. There is a risk of buckling.

Conventionally, against the possibility of buckling of the hydraulic cylinder, the buckling strength of the hydraulic cylinder is improved by preventing or restricting the rotation of the hydraulic cylinder around the pivot while the center line of the hydraulic cylinder remains straight. Things are going on.

[0006]

However, if the rotation of the hydraulic cylinder around the pivot axis is prevented while the center line of the hydraulic cylinder remains straight (see, for example, Japanese Utility Model Application Laid-Open No. 62-183698), In the retracted state of the boom device, the center of gravity of the hydraulic cylinder is located on the free end side of the pivot, so
Due to vertical vibration such as running vibration of the vehicle, the vibration load of the hydraulic cylinder is concentrated on the pivot portion, and there is a possibility that the rotation preventing structure at the pivot portion may be fatigued and destroyed.

If the rotation of the hydraulic cylinder around the pivot axis is limited while the center axis of the hydraulic cylinder is kept straight, the buckling reverses when the deflection of the hydraulic cylinder becomes large to some extent. Large buckling may occur rapidly, and the hydraulic cylinder may be damaged.

The present invention has been made in view of such circumstances, and does not cause damage to the hydraulic cylinder due to fatigue destruction or reversal of buckling of the pivot portion of the hydraulic cylinder, thereby improving the buckling strength of the hydraulic cylinder. It is intended to aim at.

[0009]

In order to achieve this object, the present invention is directed to a telescopic boom device of this kind, in which the hydraulic cylinder is provided with the cylinder end at the cylinder end opposite to the piston rod side of the hydraulic cylinder. While providing a support member to be supported on the inner surface of the front boom, after passing the other end of the wire rope through the pulley, it is fixed to the upper and lower inner surfaces of the base end of the front boom,
The support force of the pulley that receives the tension from the wire rope is caused to act obliquely with respect to the center axis of the hydraulic cylinder,
It is characterized in that a bending moment for bending the cylinder in a downward convex shape is applied by the support force of the support member and the pulley.

[0010]

According to the first aspect of the present invention, a pulley is provided at the end of the hydraulic cylinder opposite to the rod to support the tension from the wire rope, and the supporting force of the pulley is applied to the center of the hydraulic cylinder. Letting it act on the axis
A bending moment for bending the cylinder downwardly convexly can be imparted by the support force of the support member and the pulley.

Therefore, the center axis of the hydraulic cylinder is slightly bent in a required direction before the use of the telescopic boom device, and the degree of the bending is exerted by applying a load to the hydraulic cylinder in this state. Proceeds, the hydraulic cylinder does not inadvertently reverse and buckle, and the original buckling strength of the hydraulic cylinder can be enjoyed.

Further, since the pivot portion can move up and down of the hydraulic cylinder, the vibration energy of the hydraulic cylinder in the retracted state is not so concentrated, so that the fatigue of the pivot portion is reduced and the pivot portion is not broken. .

Therefore, it is possible to improve the buckling strength of the hydraulic cylinder without causing the hydraulic cylinder to be damaged due to the fatigue destruction or the reversal of the buckling of the pivot portion of the hydraulic cylinder.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

In the drawings, reference numeral 1 denotes a telescopic boom device.

The telescopic boom device 1 has a five-stage boom in which first to fifth booms are sequentially inserted from the base side thereof, and is entirely telescopically extensible. .

In the figure, 3 of the five-stage booms indicates a third-stage boom, and 4 indicates a fourth-stage boom.
Indicates a fifth stage boom. The third stage boom 3 corresponds to the base boom of the present invention, the fourth stage boom 4 corresponds to the intermediate boom, and the fifth stage boom 5 corresponds to the first boom.

Each of the third boom 3, the fourth boom 4 and the fifth boom 5 is formed in a substantially rectangular prismatic cross section, and has an upper base 3a, 4a, 5a and a lower base 3b, respectively. , 4b, 5b and side walls 3c, 4c, 5c on both sides, and the telescopic boom device 1 is provided with the upper bottoms 3a, 4a,
It is used and stored with 5a facing upward.

Inside these booms 3, 4, 5, a hydraulic cylinder 6 is provided for driving both the fourth boom 4 and the fifth boom 5 with respect to the third boom 3.

The hydraulic cylinder 6 has a cylinder body 7 and a piston rod (hereinafter, referred to as a rod) 8. The distal end of the rod 8 has first side walls 3 c at the base end of the third boom 3. The end of the cylinder body 7 on the rod 8 side is pivotally supported via a pivot 11 via a second pivot 12 to the side wall 4c of the base end of the fourth boom 4. And the second pivots 11 and 12 are connected to a central axis O described later.
It is installed in a direction orthogonal to the -O line.

The counter rod 8 of the cylinder body 7
At the end on the side (opposite side of the rod 8), the fifth boom 5
The roller 13 that rolls on the inner surface of the lower bottom 5b is installed, and the steady rest member 14 extends to just below the upper bottom 5a.
Is protruding. In addition, the roller 13 of this embodiment
Corresponds to the support member in the present invention.

The hydraulic cylinder 6 thus installed is
When supported by the rollers 13 and supported by the first and second pivots 11 and 12 and supported by the rollers 13, the expansion and contraction axes of the expansion and contraction directions correspond to the expansion and contraction directions of the third, fourth and fifth booms 3, 4, and 5. It is parallel. Note that, in FIG. 1, the OO line indicates a central axis corresponding to the telescopic axis.

Then, the second pivot 1 is
The first and second pivots 11, 1
The pulley 15 having a rotation axis parallel to the center axis O-
It is supported on O.

One end of the pulley 15 is connected to the third boom 3.
The wire rope 17 is attached to a fixing device 16 mounted on the base end of the fifth stage boom 5 and wound around the base end.

The pulley 15 and the wire rope 17 and the like in this embodiment are provided with two systems similarly formed on both sides of the hydraulic cylinder 6 in parallel.

As shown in FIGS. 2 to 4, the fastening device 16 comprises a fastening plate 18 and a fixing metal 19.

The fixing brackets 19 are fixed to both sides of the lower end of the base end of the fifth stage boom 5 by welding. Each of the fixing brackets 19 has a concave portion having an open base end and a semicircular tip end. 19a are both formed with the inside open (see FIG. 4).

The semicircular shape on the tip side of the concave portion 19a is a portion for supporting the fastening plate 18 so as to be able to swing up and down.

A circular portion 18a slightly smaller than the semicircle of the concave portion 19a is formed at the front edge of both ends of the fastening plate 18, and the circular portion 18a of each of the wire ropes 17 is formed therebetween. Two through holes 18b for screwing the end fitting 17a, which is the other end, are formed.

Therefore, by fitting the circular portions 18a of the fastening plate 18 into the concave portions 19a of the fixing brackets 19 on both sides, the wire rope 17 does not bend and the wire rope 17 does not bend as shown by arrows in FIG. Can be changed freely.

As the hydraulic cylinder 6 expands and contracts, the fourth stage boom 4 is driven to expand and contract with respect to the third stage boom 3 via the first and second pivots 11 and 12, and the wire rope 17 is moved. The fifth-stage boom 5 is driven to expand and contract via this.

The wire rope 17 extends from the base end of the third stage boom 3 to the pulley 15 so as to be substantially parallel to the central axis line OO.
From the center axis line OO to the fastening device 16 are inclined and inclined at an angle 2θ.

Therefore, the force applied to the pulley 15 by the tension applied to the wire rope 17 is a force that pushes the pulley 15 down at an angle θ with respect to the center axis line OO.

Therefore, the central axis OO of this force is
The vertical component to the line is the second pivot 12 and the roller 1
3 act on the cylinder body 7 toward the lower bottoms 4b and 5b at an intermediate portion on the rod 8 side of the cylinder body 7 to slightly project the cylinder body 7 downward. A bending moment to bend so as to form a shape.

As a result, the center axis O-
O draws a bending curve indicated by a virtual line P in FIG. This bending curve P causes the cylinder body 7 to bend downward as described above, but this bending curve P is also transmitted to the rod 8 side beyond the second pivot 12, and the rod 8 has an upwardly convex shape. Deflection occurs.

Such a small deflection is caused by the hydraulic cylinder 6
If a load for compressing the telescopic boom device 1 is applied to the fifth stage boom 5 or the like in advance, the load only increases the bending of the hydraulic cylinder 6, and the hydraulic cylinder 6 is turned over. The possibility that the hydraulic cylinder 6 is damaged due to large buckling is reduced.

The first and second stopper devices 2 correspond to the distal end of the rod 8 and the end of the hydraulic cylinder 6 on the side opposite to the rod 8 of the cylinder body 7.
1 and 22 are installed.

The first stopper device 21 includes a fixing member 23 connecting the side walls 3 c on both sides at the base end of the third stage boom 3 and further on the end side than the first pivot 11, and the hydraulic cylinder 6. At the tip of the rod 8 of the first pivot 1
1 and a bracket portion 24 further protruding than the fixing member 23, with the upper surface of the bracket portion 24 facing a small gap 25 below the fixing member 23, and a tension bolt 26.
It is connected by.

Therefore, the first stopper device 21
In the case where the bending of the hydraulic cylinder 6 is in the required direction, the bracket portion 24 is displaced in a direction away from the fixing member 23, so that the fixing member 23 does not hinder its movement, and the amount of displacement is When the gap is larger than the gap 25, the tension bolt 26 functions to prevent the hydraulic cylinder 6 from being excessively bent.

In the first stopper device 21, since the gap 25 is set, when a vertical vibration is applied to the retractable boom device 1 in the retracted state, the hydraulic cylinder 6 moves up and down within a certain range. And the energy can be dissipated by the exercise, so that there is an advantage that the fatigue destruction as in the related art is reduced.

Furthermore, the first stopper device 21 does not limit the movement of the bracket 24 at the tip of the rod 8 to both the upper and lower sides, and can be made compact with a simple structure using a tension bolt 26 or the like. Since the space can be occupied, the occupied space can be reduced, and the workability of the maintenance work performed from the base end side in the stored state of each boom is improved.

The second stopper device 22 includes a fixing member 27 for connecting between the side walls 4c on both sides at a position immediately above the second pivot 12 at the base end of the fourth stage boom 4;
And a bracket portion 28 formed integrally with the cylinder body 7 on the base end side of the pivot 12 and extending upward and facing the side surface on the base end side of the fixing member 27. The bracket portion 28 is adjustable. A push bolt 31 is provided.

Therefore, the second stopper device 22
In the case, when the bending of the hydraulic cylinder 6 is in the required direction and the bending is equal to or more than a predetermined amount, the tip of the push bolt 31 contacts the side surface of the fixing member 27, and the bending is further increased. To prevent

That is, both the first and second stopper devices 21 and 22 prevent the hydraulic cylinder 6 from excessively bending in a required direction, and reduce the increase in the bending. The purpose of this invention is to improve the buckling strength of the hydraulic cylinder 6. However, when implementing the present invention, the installation of the first and second stopper devices 21 and 22 may be omitted as appropriate.

In this embodiment, since the first and second stopper devices 21 and 22 are provided as described above, the hydraulic cylinder 6 is provided as compared with the case where the installation of these stopper devices is omitted. Is as described above.

This means that when the buckling strength to be set is constant, the buckling strength of the hydraulic cylinder 6 itself can be reduced by employing both or one of the stopper devices 21 and 22. Therefore, the hydraulic cylinder 6 can be made lightweight by reducing the diameter of the hydraulic cylinder 6 or the like.

Next, a second embodiment shown in FIG. 5 will be described. This second embodiment is different from the first embodiment described above mainly in the winding condition of the wire rope and the support member. .

In the following, portions that are the same as those in the first embodiment are given the same reference numerals in the figure, and description thereof will not be repeated.

That is, the pulley 15, the first roller 41, and the second roller 42 are provided at the end of the hydraulic cylinder 6 opposite to the rod, which is located within the base end of the fifth stage boom 5. And the second in the second embodiment.
The roller 42 corresponds to the support member of the present invention.

The pulley 15 is provided on the center axis OO of the hydraulic cylinder 6 in the same manner as in the first embodiment.
It is supported in parallel with. A first roller 41 that rolls on the inner surface of the lower bottom 5b of the fifth step boom 5 is disposed on the distal side of the pulley 15, and on the inner surface of the upper bottom 5a on the proximal side of the pulley 15 The second roller 42 that rolls is arranged.

The second roller 42 has a function as a fulcrum similarly to the roller 13 of the previous embodiment, and the first roller 41 is a hydraulic cylinder similar to the anti-sway member 14 of the previous embodiment. 6 also has a function of suppressing vertical vibration.

The pulley 15 of such a cylinder body 7
One end of the wire rope 43 is fixed to the base end of the third stage boom 3 in the same manner as in the previous embodiment, and is extended to the pulley 15 in parallel with the central axis OO. However, the fastening device 16 for fastening the other end of the wire rope 43 is installed on the inner surface of the upper bottom 5a of the base end of the fifth stage boom 5 and is upwardly inclined at an angle 2θ with the center axis OO. It is inclined. The fastening device 16 is the same as that of the previous embodiment.

Therefore, due to the tension of the wire rope 43, a force acts on the pulley 15 in a direction inclined at an angle θ upward with respect to the central axis OO.

Then, on the base end side of the pulley 15, a second
The roller 42 is disposed and the inner surface of the upper bottom 5a is used as a fulcrum, so that the cylinder body 7 is given a bending moment to bend downward by the tension of the wire rope 43 as in the first embodiment. You.

In the first and second embodiments described above, the direction in which the wire ropes 17 and 43 are stretched is appropriately set in order to impart a required bending moment to the cylinder body 7. Pulley 15 is center axis OO
May be deviated from.

Although the above embodiment has been described with reference to the case where the present invention is incorporated in a telescopic boom device having a multi-stage boom, it is needless to say that the present invention can be directly applied to a telescopic boom device having a three-stage structure. Absent.

[0057]

As described above, according to the first aspect of the present invention, a pulley is installed at the end of the hydraulic cylinder opposite to the rod to support the tension from the wire rope, and The supporting force is applied to the hydraulic cylinder at an angle with respect to the central axis thereof, and a bending moment for bending the cylinder downward in a convex shape can be applied by the supporting force of the support member and the pulley.

Therefore, the center axis of the hydraulic cylinder is slightly bent in a required direction in advance of using the telescopic boom device, and the degree of the bending is exerted by applying a load to the hydraulic cylinder in this state. Proceeds, the hydraulic cylinder does not inadvertently reverse and buckle, and the original buckling strength of the hydraulic cylinder can be enjoyed.

Further, since the pivot portion can move up and down of the hydraulic cylinder, the vibration energy of the hydraulic cylinder in the retracted state is not so concentrated, so that the fatigue of the pivot portion is reduced and the pivot portion is not broken. .

Accordingly, it is possible to improve the buckling strength of the hydraulic cylinder without causing the hydraulic cylinder to be damaged due to the fatigue destruction or the reversal of the buckling of the pivot portion of the hydraulic cylinder.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a telescopic boom device.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a top view of the fastening device.

FIG. 4 is an explanatory view related to a fixing bracket and a fastening plate.

FIG. 5 is an explanatory view of a tip structure of a hydraulic cylinder in a second embodiment.

[Explanation of symbols]

 O Central axis line 1 Telescopic boom device 3 Base boom (third stage boom) 4 Intermediate boom (fourth stage boom) 5 Front boom (fifth stage boom) 5a Upper bottom 5b Lower bottom 6 Hydraulic cylinder 7 Cylinder (cylinder body) 8 Piston rod 11 First pivot 12 Second pivot 13, 42 Support member 15 Pulley 17, 43 Wire rope

Claims (1)

(57) [Scope of request for utility model registration] 1. A base boom, an intermediate boom, and a front boom are sequentially inserted to be extendable and extendable, and a hydraulic cylinder for extending and retracting the boom is provided between the base boom and the intermediate boom in a direction parallel to the direction in which the boom extends and contracts. At the end of the boom, the tip of the piston rod of this hydraulic cylinder is at the base end of the base boom, and the cylinder end of the hydraulic cylinder at the piston rod side is at the base end of the intermediate boom. Each of the hydraulic cylinders is connected by a pivot installed in a side direction orthogonal to the direction of extension and contraction of the boom, and further, a pulley is provided at a cylinder end of the hydraulic cylinder on the side opposite to the piston rod so as to be supported in parallel with the pivot. A wire rope fixed to the base end side of the boom and the other end fixed to the base end side of the front boom is passed through the pulley, and the intermediate boom and the front boom are moved from the base boom by extension of the hydraulic cylinder. And a support member for supporting the cylinder end on the inner surface of the boom at the end of the hydraulic cylinder opposite to the piston rod. After passing the end through the pulley, it is fixed to the upper and lower inner surfaces of the base end of the tip boom, and the supporting force of the pulley receiving tension from the wire rope is inclined with respect to the center axis of the hydraulic cylinder. A telescopic boom device that acts to apply a bending moment to bend the cylinder downwardly convexly by the support force of the support member and the pulley.