JP2000007281A - Multistage telescopic boom for crane vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide multistage telescopic booms for a crane vehicle in a simple structure, in a lighter weight and easy in at adjustment of the condition of spreading a rope. SOLUTION: An expansion hydraulic cylinder 20 for connection between adjacent booms at one place on and after the second stage is arranged in the boom, and the front and rear stages of the booms are connected via an elongation rope sheave 10 and a contraction rope sheave 12 respectively provided from the second stage boom to the boom one stage before the final stage with an elongation rope 11 and a contraction rope 13. Otherwise, the total number J of the stages of the booms is in odd number, 5 or greater, and the front and rear stages of the booms are connected via the elongation rope sheaves 10 respectively provided from the second stage boom to the boom one stage before the final stage with the elongation rope 11 and a multistage contraction rope 15 having one end connected to the first stage boom 1 is bridged in J/2 turns around a plurality of multistage contraction rope sheaves 14 provided on the booms mounted with the expansion hydraulic cylinder 20, with the other end connected to the final stage boom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage telescopic boom of a crane truck capable of projecting a rear end of a second-stage boom from a rear end of a first-stage boom at the time of the most contraction.

[0002]

2. Description of the Related Art In a mobile crane having a multi-stage telescopic boom mounted on a vehicle, the telescopic boom is prevented from protruding from the front end of the vehicle body during traveling, or the amount of protrusion (so-called overhang) is reduced. It is required to do so. A mobile type having a second-stage boom rearward projecting mechanism, in which the rear end of the second and subsequent booms is projected from the rear end of the first-stage boom at the time of the most contraction, as a device that satisfies this demand. Cranes are well known.

FIG. 5 schematically shows a side sectional view of a conventional multi-stage telescopic boom having the second-stage boom rearward projecting mechanism, which will be described below with reference to FIG. The first-stage boom 1 has a second-stage boom 2, a third-stage boom 3, a fourth-stage boom 4, and a fifth-stage boom 5 inserted therein so as to be able to expand and contract sequentially. The first-stage boom 1 and the second-stage boom 2 are connected by a second-stage telescopic hydraulic cylinder 25 disposed between an outer lower surface of the second-stage boom 2 and an inner lower surface of the first-stage boom 1. . A third-stage telescopic hydraulic cylinder 26 is provided in the second-stage boom 2 and the third-stage boom 3, and the third-stage boom 3 is provided with the cylinder 21 of the third-stage telescopic hydraulic cylinder 26. The distal end of the piston rod 22 of the third-stage telescopic hydraulic cylinder 26 is attached to the second-stage boom 2.
Further, the rear end of the fourth-stage boom 4 and the front end of the second-stage boom 2 are connected via a fourth-stage extending rope sheave 10 c rotatably attached to the front end of the third-stage boom 3. They are connected by a fourth-stage extending rope 11c. The rear end of the fifth-stage boom 5 and the front end of the third-stage boom 3 are connected via a fifth-stage extending rope sheave 10d rotatably attached to the front end of the fourth-stage boom 4. Fifth-stage extension rope 11
d. On the other hand, the rear end of the fourth stage boom 4 and the front end of the second stage boom 2 are connected via a fourth stage contraction rope sheave 12 c rotatably attached to the rear end of the third stage boom 3. The rear end of the fifth stage boom 5 and the front end of the third stage boom 3 are rotatably attached to the rear end of the fourth stage boom. The fifth-stage boom contraction rope 13d is connected via the fifth-stage contraction rope sheave 12d.

Next, the operation will be described. When the third-stage telescopic hydraulic cylinder 26 is extended by L, the third-stage boom 3 becomes 2
The fourth-stage boom 4 and the fifth-stage boom 5 extend by L with respect to the second-stage boom 2, and the fourth-stage extension rope sheave 10 c
The extension rope 11c for the fourth step, the rope sheave 10d for the fifth step, and the extension rope 11d for the fifth step extend L by L, respectively. When the third-stage telescopic hydraulic cylinder 26 is contracted by L, the third-stage boom 3 contracts by L with respect to the second-stage boom 2, and the fourth-stage boom 4 and the fifth-stage boom 5 also contract by L, respectively. . That is, by expanding and contracting the third-stage telescopic hydraulic cylinder 26, the fourth-stage boom 4 and the fifth-stage boom 5 can be extended and contracted by an equal amount in synchronization. When the second-stage telescopic hydraulic cylinder 25 expands and contracts, the second-stage boom 2 expands and contracts with respect to the first-stage boom 1.

FIG. 6 shows second-stage telescopic hydraulic cylinders 25 and 3.
This shows a state in which the second-stage telescopic hydraulic cylinder 26 is most contracted, and the rear end of the second-stage boom 2 projects rearward from the rear end of the first-stage boom 1. That is, the overhang amount of the boom during traveling can be reduced.

[0006]

However, the above configuration has the following problems. (1) In order to make the rear end of the second stage boom protrude rearward from the rear end of the first stage boom at the time of contraction, the second stage telescopic hydraulic cylinder is connected to the outer lower surface of the second stage boom and the first stage boom. It is arranged between the inner lower surface. The height H3 of the box section of the second stage boom (that is, the section orthogonal to the boom extension / contraction direction) is 2
Since it is determined by the strength of the stage boom itself, the height H3 cannot be reduced to maintain the same strength. Therefore, the height H2 of the first-stage boom shown in FIG. 5 needs to be increased, which requires a large space, deteriorates visibility, and increases weight. (2) Two telescopic hydraulic cylinders, one for the second stage and the other for the third stage, are required, and the structure is complicated, the weight is heavy, and the cost is high. (3) Since the rope sheave for contraction and the rope for contraction are provided on each boom, the number and types of ropes increase,
The structure is complicated and the cost is high. In addition, the man-hours for adjusting the tension of the rope are increased.

An object of the present invention is to provide a multi-stage telescopic boom for a crane vehicle, which has a simple structure, can be reduced in weight, and can easily adjust the tension of a rope.

[0008]

Means for Solving the Problems, Functions and Effects In order to achieve the above-mentioned object, the invention according to claim 1 is arranged such that the second stage to the last stage boom can be sequentially extended and contracted on the first stage boom 1. In a multistage telescopic boom of a crane truck in which the rear end of the second stage boom 2 is protruded from the rear end of the first stage boom 1 at the time of the minimum contraction, any one adjacent boom after the second stage A telescopic hydraulic cylinder 20 for connecting between the two is arranged in the boom, and the elongating rope sheave 10 and the contracting rope sheave 12 are respectively provided from the second boom 2 to the boom one stage before the last stage. The front and rear stages of the boom are connected by an extension rope 11 and a contraction rope 13.

According to the first aspect of the present invention, each boom is extended and retracted synchronously by one telescopic hydraulic cylinder, so that the conventional second stage boom is provided between the first stage boom and the second stage boom. The telescopic hydraulic cylinder 25 becomes unnecessary, the structure is simple, and the boom can be made compact. In addition, since the telescopic hydraulic cylinder is provided inside the boom, the height of the box section of the first-stage boom can be reduced, so that the multistage telescopic boom is lighter in weight and less expensive than the conventional one. Can be configured.

[0010] The second aspect of the present invention is a first stage boom 1
The second-stage to the last-stage booms are sequentially inserted in a telescopic manner so that the rear end of the second-stage boom 2 projects from the rear end of the first-stage boom 1 at the time of the minimum contraction. The total number of stages J of the boom is set to an odd number of 5 or more, and a telescopic hydraulic cylinder 20 for connecting any one of the adjacent booms after the second stage is disposed in the boom. A multi-stage contraction rope in which the front and rear stages of the boom are connected by an extension rope 11 via extension rope sheaves 10 provided respectively to the boom one stage before the stage, and one end is connected to the first stage boom 1. 15 corresponds to a half of the total number J of a predetermined number of multi-stage contraction rope sheaves 14 provided on a boom to which the cylinder 21 of the telescopic hydraulic cylinder 20 is attached and a boom to which the piston rod 22 is attached. / 2 Turn over as reciprocating, and has a configuration that is connected the other end to a final stage boom.

According to the second aspect of the present invention, each of the booms can be extended in synchronization by extending and retracting one telescopic hydraulic cylinder attached between adjacent booms in the second and subsequent stages. The conventional second-stage telescopic hydraulic cylinder 25 is not required between the second-stage boom and the second-stage boom,
The structure can be simplified. In addition, since the telescopic hydraulic cylinder is provided inside the boom, the height of the box section of the first-stage boom can be reduced, so that the multistage telescopic boom is lighter in weight and less expensive than the conventional one. Can be configured. Furthermore, each boom can be contracted in synchronization with one contraction rope. Thereby, the contraction rope sheave and the contraction rope conventionally attached to the boom at the previous stage (the end of the boom) of the boom stage to which the telescopic hydraulic cylinder is attached can be omitted. Therefore, the adjustment of the rope tension state becomes easy, and the adjustment operation can be performed in a short time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a multistage telescopic boom for a crane truck according to the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a schematic side sectional view of a multistage telescopic boom representing the first embodiment. 2 for first stage boom 1
Second stage boom 3, third stage boom 3, fourth stage booms 4 and 5
The stage boom 5 is sequentially and elastically inserted. A telescopic hydraulic cylinder 20 is disposed inside the second-stage boom 2 and the third-stage boom 3, and the distal end of the piston rod 22 of the telescopic hydraulic cylinder 20 is attached to the rear end of the second-stage boom 2. The end of the cylinder 21 on the piston rod 22 side is attached to the rear end of the third-stage boom 3. When the boom is in the most contracted state, the telescopic hydraulic cylinder 20
The rear end of the cylinder 21 (here, the end of the boom) is configured to enter the inside of the fourth and fifth booms. Each of the extension rope sheave 10, the extension rope 11, the contraction rope sheave 12, and the contraction rope 13 are provided as follows.

The front end of the first stage boom 1 and the third stage boom 3
The rear end of the second stage boom 2 is provided at the rear end of the second stage boom 2.
They are connected by a second-stage extending rope 11a via a second-stage extending rope sheave 10a. The cylinder 21
The front end of the first-stage boom 1 is connected to a second-stage extension rope sheave 10a by a hydraulic hose 24 via a hydraulic hose sheave 23 provided on the same rotating shaft. The hydraulic hose 24 is connected to a hydraulic device such as a switching valve (not shown) provided on the vehicle body side, and supplies hydraulic oil to the telescopic hydraulic cylinder 20.

The front end of the second-stage boom 2 and the rear end of the fourth-stage boom 4 are connected to each other through a fourth-stage extending rope sheave 10c provided at the front end of the third-stage boom 3. They are connected by eye extension ropes 11c. Further, the front end of the third stage boom 3 and the rear end of the fifth stage boom 5
They are connected by a fifth-stage extension rope 11d via a fifth-stage extension rope sheave 10d provided at the front end of the stage-boom.

The front end of the first-stage boom 1 and the rear end of the third-stage boom 3 are connected to each other through a second-stage contraction rope sheave 12 a provided at the front end of the second-stage boom 2. It is connected by the eye contraction rope 13a. The front end of the second-stage boom 2 and the rear end of the fourth-stage boom 4 correspond to a fourth-stage contraction rope sheave 1 provided at the rear end of the third-stage boom 3.
It is connected by a fourth-stage contraction rope 13c via 2c. The front end of the third-stage boom 3 and the rear end of the fifth-stage boom 5 are connected to a fifth-stage contraction rope sheave 12d provided at a rear end of the fourth-stage boom 4 for a fifth-stage contraction rope. 13d.

As described above, since only the second-stage extension rope 11a and the hydraulic hose 24 pass between the inner lower surface of the first-stage boom 1 and the outer lower surface of the second-stage boom 2,
The height H1 of the box section of the first stage boom 1 is smaller than the height H2 when the second stage telescopic hydraulic cylinder 26 is provided on the outer lower surface of the second stage boom 2 as in the related art. As a result, compactness, good visibility, and light weight are achieved.

Next, the operation will be described. When the telescopic hydraulic cylinder 20 is extended by a length L, the third-stage boom 3 extends by a length L with respect to the second-stage boom 2. This allows
The fourth-stage extension rope sheave 10c provided at the front end of the third-stage boom 3 moves forward to extend the fourth-stage extension rope 11c.
The fourth stage boom 4 is moved forward by the
With the advance of the fifth stage, the fifth-stage extension rope sheave 10d moves forward and is moved by the fifth-stage extension rope 11d.
To move forward. Also, when the third stage boom 3 is extended, 2
The rope 11a for extending the second stage is the rope sheave 1 for extending the second stage.
0a is advanced, so that 2 b with respect to the first stage boom 1
The stage boom 2 is advanced. As a result, the second-stage boom 2, the fourth-stage boom 4, and the fifth-stage boom 5 also extend in synchronism with each other by the length L.

When the telescopic hydraulic cylinder 20 is reduced by the length L, the third-stage boom 3 becomes longer than the second-stage boom 2 by a length L.
Just shrink. As a result, the fourth-stage contraction rope sheave 12c provided at the rear end of the third-stage boom 3 is retracted, and the fourth-stage boom 4 is retracted by the fourth-stage contraction rope 13c. With the retreat of 4, the fifth-stage contraction rope sheave 12d retreats and the fifth-stage boom 5 is retracted by the fifth-stage contraction rope 13d. Also, 3
When the second-stage boom 3 is reduced, the second-stage contraction rope 13a is used.
Retreats the second-stage contraction rope sheave 12a, thereby reducing the second-stage boom 2 with respect to the first-stage boom 1. As a result, each boom is reduced by the length L in synchronization. FIG. 2 schematically illustrates a state of the most retracted state. At least the rear end of the second-stage boom 2 (in the present embodiment, each rear end of the second-stage boom 2 to the fourth-stage boom 4). 1
It can be made to protrude backward from the rear end of the stepped boom 1.

Although this embodiment describes a five-stage boom, the same effect can be obtained with a similar configuration for a multistage telescopic boom having another number of stages.

Next, as a second embodiment, an example in which the telescopic hydraulic cylinder 20 is mounted between the third-stage boom and the fourth-stage boom will be described. FIG. 3 is a schematic side sectional view of the multistage telescopic boom according to the present embodiment. Here, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described. The telescopic hydraulic cylinder 20 is provided inside the third boom 3 and the fourth boom 4.
Is provided, and the piston rod 2 of the telescopic hydraulic cylinder 20 is provided.
The end of the second boom 3 is attached to the rear end of the third stage boom 3, and the end of the cylinder 21 on the piston rod 22 side is attached to the rear end of the fourth stage boom 4. When the boom is in the most contracted state, the rear end of the cylinder 21, that is, the boom tip side is configured to enter the inside of the fifth stage boom. The rear end of the fourth-stage boom 4 and the front end of the second-stage boom 2 are connected to the third-stage extension rope sheave 10b provided at the rear end of the third-stage boom 3 to extend the third-stage extension rope. 1
1b. The front end of the second stage boom 2 and the rear end of the fourth stage boom 4 are connected to the third stage boom 3 via a third stage contraction rope sheave 12b provided at the front end thereof. They are connected by a rope 13b. In addition, a hydraulic hose (not shown) connected to the telescopic hydraulic cylinder 20 can be unwound and unwound freely and can be wound by a hose reel without excess or shortage.

The operation according to the above configuration is almost the same as that described in the first embodiment. That is, when the telescopic hydraulic cylinder 20 is extended by the length L, the fourth stage boom 4 is extended by the length L with respect to the third stage boom 3. This allows
The fifth stage boom 5 is advanced by the fifth stage extension rope sheave 10d and the fifth stage extension rope 11d, and the third stage extension rope 11b and the third stage extension rope sheave 10
b, and the third-stage boom 3 and the second-stage boom 2 are advanced by the second-stage extension rope 11a and the second-stage extension rope sheave 10a. As a result, the second-stage boom 2, the third-stage boom 3, and the fifth-stage boom 5 also extend in synchronization with each other by the length L. Similarly, when the telescopic hydraulic cylinder 20 is reduced by the length L, the fourth-stage boom 4 is reduced by the length L with respect to the third-stage boom 3. Thus, the fifth-stage boom 5 is retracted by the fifth-stage contraction rope sheave 12d and the fifth-stage contraction rope 13d, and the third-stage contraction rope 13b, the third-stage contraction rope sheave 12b, and the second stage Rope 13a for contraction and rope sheave 12 for second stage contraction
The third boom 3 and the second boom 2 are reduced by a. As a result, each boom is reduced by the length L in synchronization.

Any one of the second and subsequent booms
The same operation and effect can be obtained by connecting the adjacent booms with the telescopic hydraulic cylinder 20.

FIG. 4 is a schematic side sectional view of a multistage telescopic boom representing the third embodiment. Here, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
Only different parts will be described. Telescopic hydraulic cylinder 2
0 is attached to the rear end of the second stage boom 2, and the piston rod 2 of the cylinder 21 is
The second end (the rear end of the boom) is attached to the rear end of the third stage boom 3. And one multi-stage shrinkage rope 1
5, a plurality of multi-stage contraction rope sheaves 14 for reducing each stage boom are attached as follows.
That is, the first multi-stage shrink rope sheave 14a and the second multi-stage shrink rope sheave 14b are attached to the front end of the second stage boom 2. At the rear end of the third-stage boom 3, a third multi-stage contraction rope sheave 14c and a fourth multi-stage contraction rope sheave 14d are attached. One end
Multi-stage shrinkage rope 1 connected to the front end of stage boom 1
Reference numeral 5 denotes a first multi-stage contraction rope sheave 14a, a third multi-stage contraction rope sheave 14c, and a second multi-stage contraction rope sheave 1.
4b and the fourth multi-stage contraction rope sheave 14d are wound around in this order, and the other end is connected to the rear end of the fifth stage boom 5. That is, assuming that J is the total number of stages, the multi-stage shrink rope 15
Makes a J / 2 reciprocation (here, 5/2 reciprocations, that is, 2.5 reciprocations) between the first stage boom 1 and the fifth stage boom 5 (final stage boom).

According to the above configuration, the telescopic hydraulic cylinder 20
Is extended, the boom of each stage is extended by the same amount in synchronization with each action of the second stage extension rope 11a, the fourth stage extension rope 11c, and the fifth stage extension rope 11d. When the telescopic hydraulic cylinder 20 is reduced, the third-stage boom is reduced with respect to the second-stage boom 2, and the fifth-stage boom 5 is moved by the third and fourth multi-stage contraction rope sheaves 14 c and 14 d via the multi-stage contraction rope 15. To shrink. As a result, the fifth-stage extending rope 11d becomes the fifth-stage extending rope sheave 10d.
, The fourth boom 4 is reduced. That is, the fifth-stage extending rope 11d and the fifth-stage extending rope sheave 1
0d acts for shrinking the fourth stage boom. At the same time, the second-stage boom 2 is reduced with respect to the first-stage boom 1 by the multi-stage contraction rope 15 via the first multi-stage contraction rope sheave 14a. Thereby, each stage boom can be reduced in synchronization with one multistage contraction rope 15.

As described above, one multi-stage shrink rope 1
By contracting the boom by 5, the fourth-stage rope sheave 12c and the fifth-stage contraction rope sheave 12d and the fourth-stage contraction rope 13c and the fifth-stage contraction rope 13d as in the previous embodiment are omitted. Can be. Therefore, the structure is simplified, and a compact multistage telescopic boom can be obtained. In addition, since the number of ropes is reduced, the adjustment of the tensioned state of the rope is facilitated, and the adjustment operation can be performed in a short time.

Although this embodiment shows a five-stage boom, the present invention only requires an odd number of boom stages. That is, the total number of stages J is an odd number (for example, 7, 9, etc.) multistage boom with 5 or more, and any one adjacent boom after the second stage boom is connected by the telescopic hydraulic cylinder 20, and the telescopic hydraulic cylinder 20 is used. A multi-stage contraction rope sheave is provided on the boom attached to the cylinder 21 of the cylinder 20 and the boom attached to the piston rod 22, and the first-stage boom and the J
The same action and effect as described above can be obtained by hanging the multi-stage shrinkage rope connecting the stage boom (final stage) around the multi-stage shrinkage rope sheave and reciprocating J / 2 times.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a multistage telescopic boom according to a first embodiment of the present invention.

FIG. 2 is a side cross-sectional view schematically illustrating the most contracted state of the multistage telescopic boom according to the first embodiment of the present invention.

FIG. 3 is a schematic side sectional view of a multistage telescopic boom according to a second embodiment of the present invention.

FIG. 4 is a schematic side sectional view of a multistage telescopic boom according to a third embodiment of the present invention.

FIG. 5 is a schematic side sectional view of a multistage telescopic boom according to the related art.

FIG. 6 is a side cross-sectional view schematically illustrating the most contracted state of the multistage telescopic boom according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st stage boom, 2 ... 2nd stage boom, 3 ... 3rd stage boom, 4 ... 4th stage boom, 5 ... 5th stage boom, 10 ... Rope sheave for extension, 11 ... Rope for extension, 12 ... Shrinkage Rope for shedding, 13 ... rope for shrinking, 14 ... rope sheave for multi-stage shrinking, 15 ... rope for multi-stage shrinking, 20 ... telescopic hydraulic cylinder, 21 ... cylinder, 22 ... piston rod, 2
3 ... Hydraulic hose sheave, 24 ... Hydraulic hose.

Claims (2)

[Claims] 1. A second stage to a final stage boom is sequentially and elastically inserted into a first stage boom (1), and the second stage boom is at the minimum contraction.
(2) In a multi-stage telescopic boom of a crane vehicle in which the rear end of the first stage boom protrudes from the rear end of the first stage boom, a telescopic hydraulic cylinder that connects between any one adjacent booms in the second and subsequent stages. (20) is disposed in the boom, and the extension rope sheave (10) and the contraction rope sheave (12) are respectively provided from the second boom (2) to the boom one stage before the last stage. A multi-stage telescopic boom for a mobile crane, wherein the front and rear stages of the boom are connected by an extension rope (11) and a contraction rope (13). 2. The second-stage boom is sequentially inserted into the first-stage boom (1) so that the second-stage to the last-stage boom can be extended and contracted.
(2) In a multi-stage telescopic boom of a crane truck with the rear end protruding from the rear end of the first stage boom (1), the total number of stages (J) of the boom shall be an odd number of 5 or more, and any of the second and subsequent stages Or a telescopic hydraulic cylinder (20) connecting the adjacent one of the booms is provided in the boom,
From (2), an extension rope (11) is used to connect the front and rear stages of the boom via an extension rope sheave (10) provided on each of the booms immediately before the last stage, and one end of the first boom ( 1)
A predetermined number of ropes (15) connected to the boom to which the cylinder (21) of the telescopic hydraulic cylinder (20) is attached and the boom to which the piston rod (22) is attached, respectively. , Including the ropes on both ends, is reciprocated J / 2 times corresponding to half of the total number of steps (J), and the other end is connected to the final step boom. Multi-stage telescopic boom of crane truck.