JP2000296988A - Boom extending/contracting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sure cylinder support action without any sliding in a cylinder support part by providing a support member telescopically extending/ contracting and fitting a plurality of stages of support members in the outer circumference of a multistage boom extending/contracting cylinder and transmitting a cylinder thrust to the boom as the extending/contracting drive force. SOLUTION: A support S member which supports a 6-stage boom extending/ contracting cylinder C provided in the axial center of a boom B from an outer periphery comprising respective 1st-6th-stage cylinder bodies C1-C6 corresponding to respective boom bodies B1-B6, and transmits the cylinder extending/ contracting thrust to the 2nd-6th-stage respective boom bodies C2-C6 is so constituted that the small-diameter sides of 6-stage square cylindrical support members S1-S6 similar to the boom extending/contracting cylinder C are positioned in the base end sides of the boom bodies B1-B6 and telescopingly extended/ contracted and fitted into the inverse tapered state. The base ends and the tip ends of the respective support members S1-S6 are connected to the base ends of the corresponding boom bodies B1-B6 and the tip of the cylinder bodies C1-C6 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom extension device for extending and retracting a boom with a multi-stage boom extension cylinder in a boom type working machine such as a crane, an aerial work vehicle and the like.

[0002]

2. Description of the Related Art Conventionally, a technique using a multi-stage boom telescopic cylinder as a boom telescopic drive source is disclosed in Japanese Unexamined Patent Publication No. Sho 53-2.
It is publicly known as disclosed in Japanese Patent No. 2248 and others.

However, when using this multi-stage cylinder,
Since buckling is likely to occur in the extended state of the cylinder, it is necessary to take measures against this buckling.

As a countermeasure against this buckling, Japanese Unexamined Patent Publication No.
No. 73, a rail on the boom side,
2. Description of the Related Art A technique is known in which claws for engaging with rails are provided on each cylinder body of a multi-stage cylinder, and the cylinder bodies are supported from the outer periphery by the claws and rails to prevent buckling.

Further, as disclosed in Japanese Patent Application Laid-Open No. 8-34505, there is known a technique in which a claw body is provided on a boom side, and each cylinder body is supported from the outer periphery by the claw body to prevent buckling. .

[0006]

However, according to the above-mentioned known technique, since the claws and rails and the like perform the cylinder supporting action while relatively sliding, they are worn to cause backlash at the contact portion, and relatively early. As a result, the cylinder supporting action is reduced.

In addition, since the boom must be provided with a mechanism for preventing buckling of the cylinder (the above-described pawls and rails) and an interlocking mechanism for transmitting the thrust of the cylinder to the boom, the production of the boom becomes troublesome and the boom cost is reduced. Is expensive.

Accordingly, the present invention is to provide a boom extension / contraction device in which a cylinder supporting portion does not slip and a reliable cylinder supporting action can be obtained for a long period of time, and the cylinder supporting mechanism also serves as an interlocking mechanism.

[0009]

According to a first aspect of the present invention, there is provided a multi-stage boom as a boom expansion / contraction drive source having a plurality of cylinders in a boom configured to extend and contract by a plurality of stages of a boom. A telescopic cylinder is provided, and a support member, in which a plurality of support members are telescopically extended and contracted around the outer periphery of the boom telescopic cylinder, is attached to the distal end of a cylinder body corresponding to the distal end side of each support member. The base member is provided in a state where the base member is connected to the base member of the corresponding boom body.
It is configured to transmit the cylinder thrust to the boom as a telescopic driving force while supporting the boom telescopic cylinder from the outer peripheral side.

According to a second aspect of the present invention, in the configuration of the first aspect, in the support member, the outermost support member is located on the boom tip side, and the innermost support member is located on the boom base end side. It is provided in a state.

According to a third aspect of the present invention, in the configuration of the first or second aspect, the boom telescopic cylinder is provided such that the large diameter side is located at the boom base end side and the small diameter side is located at the boom tip end side.

According to a fourth aspect of the present invention, in the configuration of the third aspect, each support member of the support member is provided for each cylinder body except the most advanced cylinder body in the boom telescopic cylinder, and the most advanced cylinder body corresponds. It is directly connected to the boom body.

According to a fifth aspect of the present invention, in the configuration of any one of the first to fourth aspects, the boom telescopic cylinder and the support member are provided at positions deviated from the boom axis.

According to a sixth aspect of the present invention, in the configuration of any one of the first to fifth aspects, each support member of the support member and the boom body are connected by a connecting shaft orthogonal to the boom axis and the axis of the connecting shaft. It is connected so that it cannot rotate around the heart.

According to the above construction, the cylinder expansion / contraction thrust is transmitted to the boom (each boom body) by the support member, and the boom expands / contracts. At this time, the cylinder is supported from the outer peripheral side by the support member, and the buckling is prevented.

That is, the support member serves both as an interlocking mechanism and a cylinder supporting mechanism.

As a result, the boom structure is simpler than in the case where both mechanisms are separately provided, and the boom cost can be reduced.

Further, since the interlocking mechanism of the boom does not depend on the wire rope passing through the gap of the boom body as in the related art,
The gap between the boom bodies can be reduced, and the boom body can be reduced in size and weight.

On the other hand, the support member is connected to the cylinder and the boom, and expands and contracts integrally with the cylinder and the boom. Therefore, no slip occurs in the cylinder support mechanism, and neither abrasion nor rattling due to the slip occurs. For this reason, the cylinder supporting action can be ensured for a long time.

Incidentally, as a measure to prevent buckling of the cylinder,
It is conceivable to provide the boom telescopic cylinder in a state where the large-diameter side with high buckling strength is located on the boom tip side (the small-diameter side with low buckling strength is on the boom base end side) (thickened state).

However, in this case, the weight of the boom tip side in the state where the boom is extended is increased by the weight of the cylinder, so that the lifting ability of the crane is reduced. Further, the strength of the base end side of the boom needs to be increased in accordance with an increase in the weight of the boom tip side, so that the boom cost increases.

On the other hand, according to the structure of the present invention, since the buckling of the cylinder can be prevented by the support member, the boom telescopic cylinder is moved to a state in which the large-diameter side is located at the base end side of the boom. State) in the boom.

Therefore, there is no possibility of causing adverse effects such as a decrease in the suspension capacity and an increase in the boom cost.

According to the second aspect of the present invention, since the support member which expands and contracts in a telescopic shape is provided in a tapered state in which the large-diameter side is located at the tip end side of the boom, the support member, each cylinder body and the boom are provided. Connection with the body is facilitated.

By the way, unlike the other cylinder bodies, the state-of-the-art cylinder body does not obstruct the contraction movement of the boom even if it is directly connected to the tip boom.

Therefore, the weight of the boom tip side can be reduced by omitting the support member for this state-of-the-art cylinder body.

On the other hand, according to the structure of claim 5, since the boom telescopic cylinder and the support member are provided at positions deviated from the boom axis, a surplus space inside the boom can be secured in the boom reduced state. . For this reason, it becomes possible to provide another structure, for example, a jib, in this surplus space so as to be able to freely enter and exit from the boom tip side.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

In this embodiment, as shown in FIGS. 1 and 2, a basic boom (first-stage boom body) B1 and second to sixth-stage boom bodies B2 to B6 are fitted in a telescopic manner. The step boom B is taken as an example to be applied.

Each boom body B1 is attached to the axis of the boom B.
Corresponding to the first to sixth stages of the cylinder bodies C1 to C6.
6 and a support member S that transmits the cylinder expansion / contraction thrust to each of the second to sixth-stage boom bodies C2 to C6 while supporting the cylinder C from the outer periphery to prevent buckling of the cylinder C from outside. Is provided.

The boom telescopic cylinder C is provided in a tapered state in which the larger diameter side is located at the base end side of the boom.
As shown in (1), it expands and contracts between the fully extended state and the fully contracted state.

In this case, in order to reduce the cylinder load as much as possible, it is desirable to control the operation so that the cylinder expands in order from the large diameter side when expanding and contracts in order from the small diameter side when reducing as shown in both figures.

The support member S includes a boom telescopic cylinder C
Same six-stage square tubular support members S1 to S6
Is configured to be telescopically fitted and telescopic in a tapered state in which the small diameter side is located at the boom base end side, and the base end of each support member S1 to S6 is provided at the base end of the corresponding boom body, The tip portions are connected to the tip portions of the corresponding cylinder bodies, respectively.

This connecting structure is common to each stage. For example, FIG. 3 shows first to third stage boom bodies B1 to B3 and a cylinder body C.
1 to C3, FIG. 4 shows a connecting portion between the first-stage boom body B1 and the support member S1, and FIG. 5 shows a connecting portion between the third-stage boom body B3 and the cylinder body C3. FIG. 6 shows the second and third stage cylinder bodies C2 and C2.
C3 and support members S2 and S3 are shown.

As shown in the figures, each of the cylinder bodies C1 to C
6, a round shaft-like connecting shaft 1 orthogonal to the cylinder shaft center (boom shaft center) is protruded by welding or the like on the outer periphery of the tip end.
A stop 2 is attached to the tip of each of the support members S1 to S6, and the stop 2 and the connection shaft 1 are screw-connected.

A round connecting shaft 3 protrudes from the base member outer periphery of each of the support members S1 to S6 at right angles to the member axis (boom axis), while each of the boom members B1 to B6.
A stopper 4 (having the same shape as the stopper 2) is attached to the base end of the connecting shaft 3, and the connecting shaft 3 and the stopper 4 are screw-connected.

In FIGS. 4 and 5, the cylinder bodies C1, C
For the connection between the support member 3 and the support members S1 and S3 and the connection between the support members S1 and S3 and the boom members B1 and B3, only one side is shown in a so-called cantilever state for simplification of the drawing. They are connected symmetrically in a so-called double-supported state.

In this way, the cylinder members C1 to C6 and the boom members B1 to B6 are linked and connected via the support members S1 to S6, and the cylinder members C1 to C6 are supported from the outer periphery by the support members S1 to S6. It is configured to prevent buckling.

As described above, the support member S is connected to the cylinder C
Since it is connected to the boom B and the boom B in a state of being integrally extended and retracted, no slippage occurs in the cylinder support portion, and no abrasion or backlash due to the slippage occurs. For this reason, the cylinder supporting action can be ensured for a long time.

Further, since the support member S also serves as an interlocking mechanism and a cylinder supporting mechanism, the boom structure is simplified as compared with the case where both mechanisms are separately provided, and the boom cost can be reduced.

Further, since the buckling of the cylinder C can be prevented by the support member S, the boom telescopic cylinder C can be provided in the boom B in a tapered state in which the large diameter side is located at the base end side of the boom as shown in the figure. Therefore, there is no possibility that the increase in the weight of the boom tip side causes a drop in the suspending ability or an increase in the boom cost.

Each of the support members S1 to S6
In order to make the weight as light as possible, window holes 5 are provided in the peripheral wall as shown in FIG. However, this window hole 5 ...
Is not essential and may be provided as needed.

Other Embodiments (1) Regarding the most advanced sixth cylinder body C6, unlike the other cylinder bodies C1 to C5, as shown in FIGS. The connecting shaft 3 and the stopper 4 may be directly connected without using the support member.

Even in this case, unlike the other cylinder bodies C1 to C5, the connecting portion does not hinder the boom reduction movement, and the weight of the boom tip side can be reduced.

(2) Another example of the connection structure between the cylinder body and the support member is shown in FIGS. In the figure, the third cylinder body C3 is taken as an example.

On the outer peripheral surface of the cylinder body C3, a connecting shaft 6 having a square axis shape (not limited to the square in the illustrated example but may be various polygons) is protruded, and the inner periphery of the support member S3 has a U-shape in a side view. The receiving member 7 is attached and the connecting shaft 6 is engaged with the receiving member 7 so as to be closed by a stopper member 8 so as to be closed.

According to this configuration, the cylinder C3 cannot rotate around the axis of the connecting shaft 6, so that the cylinder C
The buckling prevention effect of No. 3 is higher.

(3) As shown in FIG. 11, the boom telescopic cylinder B and the support member S may be provided at positions shifted from the boom axis. In this way, a surplus space in the boom is secured in the boom contracted state, and in this space,
If necessary, the jib J to be added to the end of the boom can be housed in a state where the jib can be freely taken in and out from the end of the boom.

(4) In the above embodiment, the most advanced boom body (sixth boom body B6 in the case of a six-stage boom) is also extended and retracted by the boom extendable cylinder C. May be expanded and contracted by a known rope expansion and contraction mechanism using a wire rope and a sheave. One example is shown in FIG.

Here, a six-stage boom is taken as an example, and only the extension mechanism is shown.

9 is the sixth boom body B which is the most advanced boom body
6, one end of the extension rope 10 passed through the sheep 9 is at the distal end of the fourth boom body B4, and the other end is at the distal end of the fifth boom body B5. These are connected to each other to form a rope extension mechanism, and the sixth boom body B6 is configured to extend by the action of the extension rope mechanism when the fifth boom body B5 is extended.

In the case of the rope reducing mechanism, a rope guide sheep is provided on the base end side of the fifth boom body B5, and one end of the reduced rope passed through this sheep is connected to the fifth boom body B5.
5 and the other end is connected to the distal end of the sixth boom body B6.

Further, the lower boom body (the fifth boom body B5 of the six-stage boom) and the lower boom body (the fourth boom body) may be expanded and contracted by the rope expansion and contraction mechanism. Good.

(5) The boom telescopic cylinder C is desirably provided in a tapered state as in the above embodiment, but may be provided in an inverted (tapered) state.

(6) The support member S and the boom telescopic cylinder C and the boom B are preferably connected in a double-supported state, but may be connected in a cantilevered state to reduce the weight.

(7) The support member is not limited to a square tube, but may be a polygonal tube other than a square, a cylinder, or a combination of a plate and a bar instead of a tube.

[0057]

As described above, according to the present invention, a support member comprising a plurality of stages of support members is provided on the outer periphery of the boom telescopic cylinder.
The boom telescoping cylinder is supported from the outer periphery to prevent buckling while transmitting cylinder thrust to the boom as telescoping driving force. Simple and low boom cost.

Further, since the support member is connected to the cylinder and the boom, and expands and contracts integrally with the cylinder and the boom, no slip occurs in the cylinder supporting portion, and no abrasion or backlash due to the slip occurs. For this reason, the cylinder supporting action can be ensured for a long time.

Further, since the buckling of the cylinder can be prevented by the support member, the boom telescopic cylinder is provided in the boom with the large-diameter side located at the base end side of the boom (tapered state). It becomes possible.

Therefore, there is no danger that the cylinder will be hindered, such as when the cylinder is provided in a thickened state.

According to the second aspect of the present invention, since the support member which expands and contracts like a telescope is provided in a tapered state in which the large-diameter side is located at the front end side of the boom, the support member and the cylinder and the boom are connected to each other. Connection becomes easy.

According to the fourth aspect of the present invention, since the support member is omitted from the most advanced cylinder body, the weight at the boom tip side can be reduced.

On the other hand, according to the fifth aspect of the present invention, since the boom telescopic cylinder and the support member are provided at positions deviated from the boom axis, it is possible to secure a surplus space inside the boom when the boom is contracted. . For this reason, it becomes possible to provide another structure, for example, a jib, in this surplus space so as to be able to freely enter and exit from the boom tip side.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are schematic side sectional views showing states of full extension, one-stage reduction, and two-stage reduction of a boom by a boom extension device according to an embodiment of the present invention.

FIGS. 2A, 2B, and 3C are schematic side sectional views showing a state in which the boom is reduced stepwise from the state of FIG.

FIG. 3 is a partially enlarged view of FIG. 1;

FIG. 4 shows a first-stage support member and a first-stage support member in the apparatus
It is sectional drawing which shows the connection part of a stage boom body and a 1st stage cylinder body.

FIG. 5 is a cross-sectional view showing a connecting portion of a third-stage support member, a boom body, and a cylinder body.

FIG. 6 is a perspective view of a connection portion between a second and third stage cylinder bodies and a support member.

FIG. 7 is a schematic side sectional view showing a boom fully extended state by a boom extension device according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a connecting portion of a sixth-stage cylinder body and a boom body in the same device.

FIG. 9 is a view corresponding to FIG. 5 of a boom extension device according to still another embodiment of the present invention.

FIG. 10 is an exploded perspective view showing a connection structure between a cylinder body and a support member in the same device.

FIG. 11 is a schematic side view of a boom extension device according to still another embodiment of the present invention.

FIG. 12 is a schematic side view of a boom extension device according to still another embodiment of the present invention.

[Explanation of symbols]

B Boom B1 to B6 First to sixth stage boom body C Boom telescopic cylinder C1 to C6 First to sixth stage cylinder body S Support member S1 to S6 First to sixth stage support member 1 Connect cylinder and support member Connection shaft of cylinder body for connecting 2 Stopper of support member 3 Connection shaft for connecting support member and boom body 4 Stopper for boom body 6 Square axis connection shaft for connecting cylinder body and support member 7 Support member receiving member connected to connecting shaft

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F205 AA05 AC02 BA06 CA03 CB02 CB16 CB17 3F333 AA08 AB04 BA12 BD02 DA02 DA08 DB08

Claims (6)

[Claims] 1. A multi-stage boom telescopic cylinder as a boom telescopic drive source having a multi-stage cylinder body is provided in a boom configured to be telescopic by a multi-stage boom body. A support member having a plurality of support members telescopically fitted in a telescopic manner is attached to the distal end of the cylinder body corresponding to the distal end of each support member, and the proximal end of the boom body corresponding to the proximal end. A boom telescopic device configured to transmit cylinder thrust to the boom as a telescopic driving force while supporting the boom telescopic cylinder from the outer peripheral side by the support member. 2. The support member according to claim 1, wherein the outermost support member is located at the front end of the boom, and the innermost support member is located at the base end side of the boom. A boom telescopic device as described. 3. The boom telescopic device according to claim 1, wherein the boom telescopic cylinder is provided with the large-diameter side positioned at the boom base end side and the small-diameter side positioned at the boom front end side. 4. The support member of the support member,
4. The boom telescopic device according to claim 3, wherein each of the boom telescopic cylinders is provided for each of the cylinders except the most advanced cylinder, and the most advanced cylinder is directly connected to the corresponding boom. 5. The boom telescopic device according to claim 1, wherein the boom telescopic cylinder and the support member are provided at positions deviated from the boom axis. 6. The support member of the support member and the boom body are connected to each other by a connecting shaft orthogonal to the boom axis and in a non-rotatable state around the axis of the connecting shaft. The boom extension and contraction device according to any one of 1 to 5.