JPH0356398A - Overhanging jib structure in telescopic boom of crane - Google Patents

Abstract

PURPOSE:To enable a jib to overhang over a boom heat by connecting the end parts of first link and a second link, the base parts of which are rotatably fitted at the boom head side part of an innermost boom and the jib base part respectively, and engaging the U-formed engaging part at the end part of an overhanging rod detachably with the connecting pin. CONSTITUTION:One side of the base part of a jib 11 mounted at the side part of the outer boom 1 of a telescopic boom is connected to one side of the boom head 6 of an innermost boom 5 in the contracted state by a connecting pin 9, and the innermost boom is then slightly extended as well as the jib is pulled out. At the time of pulling this jib out, an overhanging rod 20 is rotated around the pin fitting part 19 of the base part thereof to engage a U-formed engaging part 28 at its end part with a connecting pin 34 for connecting the end parts of a first link 30 and a second link 32, the base parts of which are fitted rotatably at the side part of a boom head and the jib base part respectively. The telescopic boom is then slightly contracted to push the connecting pin engaged with U-formed engaging part of overhanging rod out toward the boom head upper side thus the jib just out.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides an overhanging jib structure in a telescopic boom of a crane, and in particular, a system for preventing the jib from being unintentionally extended at the end of extending the jib over the boom head of the telescopic boom. The present invention relates to an overhanging jib structure for a telescopic boom of a crane that can prevent the occurrence of excessive rotation.

(Prior Art) As an example of an overhanging jib structure in a conventional crane telescopic boom, there is one as shown in Figs. (see official bulletin).

In this device, the base of the outer boom 1 of the telescopic boom A is pivotally connected to a swivel base on the vehicle body frame (not shown), and the outer boom 1 is raised and lowered by a lifting cylinder (not shown). A truck crane that performs cargo handling work for each load by extending and retracting a telescopic boom A using a hydraulic cylinder or the like, and hoisting and unwinding lobes using a winch (not shown) on a swivel platform,
On the lateral side of the outer boom 1, the base is attached to the telescopic boom A.
A jib 11 facing the boom head 6 side is removably stored.

3 With the jib 1 stowed on the side surface of the outer boom 1 of this telescopic boom A,
) is rotatably connected to the lower side of the boom head 6 with a connecting pin 9. Thereafter, by releasing the stored state of the jib 11 on the side of the outer boom 1 and slightly extending the oil cylinder (not shown) in the telescopic boom A, the inner boom 2,
3 and 5, pull out the jib 11 with the connecting pin 9 attached to the boom head 6 to the left side from the storage position shown in FIG. 8, and then manually move the jib king 1 clockwise around the connecting pin 9. , and then rotate it back and forth slightly to remove the engagement pin 17 between the end of the extending rod 16 and the bracket unit 4 at the center of the jib 11, and then remove the engaging pin 17 between the end of the extending rod 16 and the bracket unit 4 at the center of the jib 11. After releasing the storage state of lot 16, attach the end of the rod 16 to the engagement pin 17 on the bracket 1a at the top of the outer boom 1.
(See Figure 9).

After that, the inner boom 5 of the telescopic boom A is contracted by contracting a hydraulic cylinder (not shown) in the telescopic boom A,
Rotate the boom head 6'' in the 4-meter direction (Figure 9) around the connecting pin 9, and
9 and the left side in FIG. Remove the engagement pin 17 and attach the end of the extending rod cord 6 to the bracket 14.
is fixed with the engagement pin 17, the side of the jib 11 is retracted, and the jib 11 is extended over the boom head 6 of the telescopic boom A to be in a cargo handling position.

By the way, the jib 11 is extended above the boom head 6 of the innermost boom 5 by the reverse operation of the jib 11.
1 is stored on the side of the outer boom 1.

Also, for example, Tokko Sho 4. 8-2 4. 8 6
Publication No. 6 states that between the base of the jib removably stored under the outer boom of the telescopic boom and the side of the outer boom,
After both ends of the telescoping rod are removably pivoted and the jib base is pivoted to the - side of the boom head of the innermost boom, the telescoping boom is erected by a luffing cylinder, and the boom head side of the innermost boom is erected. The jib is suspended from the pivot point to the boom head, and then, by contracting the hydraulic cylinder in the telescopic boom, the hanging jib is rotated around the pivot point to the boom head and moved to the upper side of the boom head. This document describes an extended jib structure for a telescopic boom of a truck crane in which the jib is extended and the extended jib is placed in a cargo handling position, and the extended jib is stored under the outer boom by substantially the reverse operation.

Furthermore, in Japanese Patent Application Laid-Open No. 12594/1986, one leg of a jib is pivoted to one side of the top of the innermost boom of a telescoping boom, and the other leg of the jib and the telescopic boom are connected to each other. Inside (
Intermediate) The bases of the second to fourth rods are pivoted to the boom end and the top of the outer boom, respectively, on the opposite side of the pivoting side of the one side leg of the jib, and After manually inserting and connecting the connecting pin at the end of the fourth rod, the jib stored on the side of the outer boom is released from the stored state, and then the telescopic boom is extended by the telescopic cylinder inside the telescopic boom. An overhanging jib structure for a telescopic boom of a crane, in which the jib is extended over the rectangular part of the innermost boom, and the jib extended over the top of the innermost boom is stored in the side of the outer boom by substantially the reverse operation. It is written about.

(Problem to be Solved by the Invention) However, in the extending jib structure of the crane shown in FIGS. 8 and 9, there is a Connect one side of the base (leg) of the jib stored on the outside of the boom] 1 with the connecting pin 9
After attaching the outer boom, the jib 11 is released from the stored state on the side part, and then the telescopic boom A is slightly extended by a hydraulic cylinder (not shown) in the telescopic boom A, and the jib 1]
-, together with the innermost boom 5, as shown in Fig. 9, and
4, and attach the end of the protruding rod 16 to the bracket 1a at the top of the outer boom.
Pin it so that it can rotate.

Thereafter, the telescopic boom 8 is slightly retracted, the boom head 6 is pulled toward the top side of the outer boom 1, the jib 1 is rotated clockwise around the connecting pin 9 (Fig. 7), and the boom head 1 is rotated clockwise (Fig. 7). - After connecting the leg on the other side of the base of the jib 1l extending above the boom head 6 with a connecting pin, remove the connecting pin 17 between the end of the extending rod 6 and the bracket 1a at the top of the outer boom 1, and The end of the protrusion rod 16 is fixed to the bracket 14 with the connecting pin 7 and stored, and the protrusion shib 11 is
The plan was to prepare for cargo handling operations.

For this reason, while the base is pinned to the bracket 13 at the base of the jib 11, its end is secured to the bracket ↑4 at the center of the jib 11 with an engagement pin ]-7, and the tensioner stored in the side of the jib 11 is fixed. After the extension rod 16 is released from its retracted state by pulling out the engagement pin 17 with the bracket 4, the end of the extension rod 16 is connected to the bracket 1a at the top of the outer boom 1 with the engagement pin 17. Next, by slightly contracting the inner boom 2, the jib 11 is extended to the outside of the boom head 6 (to the left in FIG. 18-1 to the other side with a connecting pin (not shown), then pull out the retaining pin 17 from the bracket 1-6, and insert the extending rod 1-6.
Jib whose end is pushed into the bracket 14 on the side of the jib] 1, fixed with the same engaging pin 7, and stored on the side of the jib 11]-1
- connection pin 9 connecting the boom head 6 and the base of the jib 1, the connection point between the base and end of the extension rod 16, the brackets 1 and 13, and the bracket 1 - at the initial or final stage of extension. Since the crossing was done manually or by using the inertia of the rotating jib 11, it required troublesome manual operation. There is a risk that impact force or noise will be generated on the other side of the head 6, and it is also necessary to take measures to increase the strength of each part.

In addition, when storing the jib 11 extending above the boom head of the innermost boom 5 on the side of the outer boom 1, the telescopic boom A
After contracting the boom head 6 of the innermost boom 5 to bring it close to the top of the outer boom, the engagement pin 17 of the bracket 14 is
Bracket] From 4? Pull out the extension rod 16, fix the end of the extending rod 16 to the bracket 11a, and fix the engaging pin 17 to the jib 1.
After removing the connecting pin (l[l8, not shown) between the leg on the other side of the base and the other side of the boom head 6, the innermost boom 6 is slightly extended by a hydraulic cylinder (not shown) in the telescopic boom A.
When the jib 11 is rotated counterclockwise around the connecting pin 9 via the extending rod 16 and bent toward the side of the outer boom 1 as shown in FIG. 9, the innermost boom 5 is excessively extended. Due to the overhang rod. There was a risk of damage to 6.

In addition, the above-mentioned special public service 48-24. 8 6 In the extending jib structure of the telescopic boom of a truck crane described in Publication No. 6, when folding the jib extending over the boom head of the telescopic boom, after contracting the telescopic boom and collapsing it, Connect the telescopic rod and the jib with a connecting pin, lift the telescopic rod by the handle and insert the pin to make the telescopic rod retractable. Then, remove the suspension wire, etc., raise the telescopic boom again, and lift the jib. Since the connecting pin between the telescopic rod and the jib was suspended from a pin on the boom head and moved beyond its dead point, the intermediate boom was slightly extended just before the connecting pin crossed the deck I point. This required cumbersome operations such as raising the extension boom.

In addition, in the overhanging jib structure of the telescopic boom of a crane described in the above-mentioned Japanese Patent Application Laid-Open No. 61-12594, the base of the second rod is moved largely laterally from the end of the outer boom. Not only does it have to be supported by a protruding bracket and the fourth lot has to be quite long, but when the telescoping boom is extended and the jib is folded, for example, if the telescoping boom is extended too much, it becomes pin-connected to each other. There is a risk that the link may be destroyed, and additionally, there are problems such as the need for supervision by an auxiliary worker to prevent this.

In order to solve the problem of the conventional example, the present invention removably attaches a jib to the outer boom side of a telescopic boom, and attaches the jib to the boom head side of the innermost boom in the contracted state of the telescopic boom. One side supporting leg is removably connected with a connecting pin, and the base of the extension rod of the jib is rotatably connected to the vicinity of the top of the outermost boom, and the base is connected to the outermost boom near the top. The ends of the first link and the second link, which are rotatably attached to the side of the boom head and the base of the jib, respectively, are connected by a connecting pin, and the end of the overhanging rod is engaged in a U-shape with the connecting pin. It is an object of the present invention to provide an overhanging jib structure for a telescopic boom of a crane that can solve the above-mentioned problems by removably engaging parts.

(Means for Solving the Problems) In order to solve the problems of the conventional example as described above, the present invention removably attaches a jib to the outer boom side of a telescoping boom so that the telescopic boom can One side support leg of the jib is removably connected to the side of the boom head of the inner boom with a connecting pin, and the base of the extension rod of the jib is rotatably connected to the vicinity of the top of the outer boom, and,
Connecting the ends of a first link and a second link whose bases are rotatably attached to the boom head side of the innermost boom and the base of the jib, respectively, with a connecting pin, and 12 connecting the overhang to the connecting pin. The U-shaped engaging portion at the end of the rod is removably engaged.

(Function) Since the present invention has the above-described configuration, one side of the base of the jib attached to the outer boom side of the telescopic boom is connected to one side of the boom head 1 of the innermost boom in the contracted state with a connecting pin. After the connection, the innermost boom is slightly extended and the jib is pulled out, and when or after the jib is pulled out, the extension rod is rotated around the pinned part at its base and the end of the boom is pulled out. The U-shaped engaging portion is engaged with a connecting pin that connects the ends of the first e-link and the second link, the bases of which are rotatably attached to the side of the boom head and the base of the jib, respectively, and then the telescopic boom is By slightly reducing the
After pushing out the connecting pin that engages with the U-shaped retaining part of the extending rod to the boom head 2 side and extending the shib to the boom head 2, the supporting leg on the other side of the jib is pushed out to the other side of the boom head. with a connecting pin, and then connect the U at the end of the overhang rod.
Remove the shaped engaging portion from the connecting pins at the first and second link ends,
Also, by substantially reversing the above steps, the jib extending over the boom head is retracted to the side of the outer boom.

(Example) Hereinafter, an example of an overhanging jib structure in a telescopic boom of a crane according to the present invention will be described with reference to FIGS. 1-7. Note that the same names and symbols are used for parts common to the conventional example shown in FIGS. 8 and 9.

In FIGS. 1 to 7, A is a telescopic boom whose base is rotatably pivoted to a swivel base on the body frame of a truck crane (not shown), and is operated to raise and lower by a hoisting cylinder (not shown); 1 is a telescopic boom A; The outer boom 1 has its base pivoted on a swivel platform of a truck crane (not shown), and is operated to raise and lower by means of a lowering cylinder. 2, 3, 4, and 5 are the second, third, and fourth inner booms and the innermost booms that are slidably attached to the inside of the outer boom A. These booms 2 to 5 are the telescopic boom A. The outer boom is extended and retracted by a hydraulic cylinder (not shown) provided inside. 6 is the boom head at the top of the innermost boom 5, 7 is the boom head 1-6
9 is a connecting pin between the support leg 12 of the jib and the end of the support shaft 7 on the boom head 6.

]-9 is an overhang rod l': 20 is a connecting pin that pivotally connects the bases of the two base rods constituting the base to the bracket 1a on one side of the top of the outer boom 1; 22, 22 are the base rods 2;
1, 23 is a long hole provided in the connecting piece 22, 24 is an end rod constituting the end of the extending rod 20, 25 is a connecting piece of the end rod 24; The connecting piece 25 is slidably inserted between the connecting pieces 22, 22. Moreover, a pair of holes 26 and 27 are provided in this connecting piece 25,
The holes 26 and 27 are arranged at approximately equal intervals to the length of the elongated hole 23 of the connecting piece 22.

28 is a U-shaped engagement portion provided at the tip of the end rod 24;
9 is a connecting pin that is inserted through the elongated holes 23 and 23 of the connecting pieces 22 and 22 and into the hole 26 on the end side of the connecting piece 25 to rotatably connect the base lot 2 soil and the end rod 24; 29
is a connecting pin that can be inserted into the hole 26 of the connecting piece 25 through the long holes 23, 23 of the connecting pieces 22, 22-15. By inserting this connecting pin 29a, the base rod 21 and the end rod 24 are aligned in a straight line. When the rods 21 and 22 are pulled out, both rods 21 and 22 are connected to the connecting pin 2.
Refracts around 9.

30 is a first link whose base is pivoted to the side of the boom head 6 with a mounting pin 31, 32 is a second link whose base is pivoted to the base of the jib 1 with a mounting pin 33, and 34 is the first and second link. A connecting pin connects the ends of the links 30 and 32, and the U-shaped engaging portion 28 of the end rod 24 of the extending rod 2 is inserted into the connecting pin 34 at a suitable time.

Reference numeral 36 indicates an engagement pin which is provided slightly toward the center of the bottom wall of the U-shaped engagement portion 28 of the end rod 24 and is parallel to the connecting pin 34 at the first and second link ends; The hook 37 is provided near the end of the first link 30.
At the end of the clockwise rotation (FIG. 1), the first link 30 engages with the engagement pin 36 at the end of the extension rod 20.
Excessive rotation at the final stage of extension of the jib 11 is restricted via the connecting pin 34 and the second link 16 32.

In addition, the solid line in the plan explanatory diagram of the upper figure shows the main part of the state in which the inner booms 2 to 5 are contracted and the jib 1]- is extended over the boom head 6 of the telescopic boom A, and a point in the figure The chain line indicates the jib 11A. Overhang rod 2OA, 1st,
The relative positions of second links 30A, 32A, etc. are shown. However, in FIG. 1, the outer boom 1 is shown moved to the right with respect to the inner booms 2 to 5 by a dashed line A.

The two-dot chain line in FIG. 1 indicates the jib 1 in the retracted state].
The overhanging rod 20B, the first link 30B, and the second link 32B on the way from the IA to the overhanging position 1]
The intermediate position is shown in a plan view.

Next, the operation of this embodiment will be explained.

First, on the swivel platform of the truck crane (not shown),
After connecting the one side supporting leg l2 of the base of the jib 11 stored on the lateral outside of the outer boom 1 of the horizontally lying telescopic boom A to one side of the boom head 6 of the innermost boom 5 with the connecting pin 9, the jib'51 Release the stored state.

Next, the first to fourth inner booms 2 to 4 and the innermost boom 5 were slightly extended (in Fig. 1, the outer boom 1 is located at the dashed-dotted line position IA with respect to the inner booms 2 to 5).
．． (shown as moving backward), the base of the bracket is located at the top of the outer boom 1. 1. a Connect pin 1 to A.
9 Release the stored state (not shown) of the extension rod 20 connected at A and stored outside the outer boot tz 1-,
The extending rod 20 is connected to the connecting pin 9 a. Rotate clockwise around A to position 20A on the dashed-dotted line in Fig. t.

On the other hand, the base of the first link 30A, whose end is rotatably connected by a connecting pin 34A, is attached to the end of the second link 32A, whose base is pivoted to the base of the jib 1 by a mounting pin 33A.
It is rotatably attached to the boom head 6 with a mounting pin 31, forming a rightward V-shape as shown by the dashed line in Fig. 1 (this is the same shape as the first link 30 and second link 32 in Fig. 6). .

The base of the first link 30 and the base of the second link 32 are rotatably attached to the base of the boom head 6 and the jib 1 by means of mounting pins 31 and 33, respectively. Both of these rosodos 30 and 32
The end portions may be rotatably connected by a connecting member 34, and the operation of this structure is the same as described above.

Next, the connecting pin 29a is pulled out from the long holes 23, 23 of the connecting pieces 22, 22 of the base rod 21 of the overhang rod 20 and the hole 26 of the connecting piece 25 of the end rod 24, and the end rod 24 is connected to the base rod. 21 and move the connecting pin 29 along the long holes 23, 23 of the connecting pieces 22, 22 (this base rod 2J and end rod 2
The refraction state of 4 is at the dashed line position 21 in FIG. C.2
4. C), insert the U-shaped engaging portion 28 of the bent end rod 24 into the connecting pin 34, return the bent base rod 21 and end rod 24 to a straight line, and then insert the bent end rod 24 into the long holes 23, 23. Insert the connecting pin 29a into the hole 26 to connect the connecting pieces 22, 22, and 25 to the single-dot chain positions fi120A, 30A, and 32A in FIG. 19, or the solid line positions 20, 30, and 32 in FIG. .

Thereafter, when the innermost boom 5 is retracted by a hydraulic cylinder (not shown) in the telescopic boom A, the jib 1-1 leg 12 is connected to the connecting pin 9 at the end of the shaft 7 on the boom head 6.
The first link 3o is pulled in by the rightward pulling force P by the mounting pin 31, while the base of the extending rod 20 is fixed to the outer boom 1 by the connecting pin 19, so that the connecting pin 3
4 comes into contact with the bottom wall of the U-shaped engagement portion 28, the connecting pin 34 is pushed to the left in FIG. move.

As a result, the support leg 12A of the jib IIA is pushed to the left via the second link 32A connected to the second e-link 30A at the dashed-dotted line position by the connecting pin 34A.
The second link 32 to which the mounting pin 33 is attached to the rectangular base is
The mounting pin 33A at the base is located at the dotted line position on the jib IIA.
, the rotation (revolution) in the direction of arrow R around the connecting pin 9 (lower side of the construction drawing) to the end of the shaft 7, and the rotation (rotation) in the direction of arrow S around the mounting pin 33. At the same time, the second
The link 32 and the connecting pin 34 are connected to the solid line position 3 in the same figure via intermediate positions 30B, 32B, and 34B indicated by the two-dot chain line in FIG.
0, 32, and 34, and the jib 11 is extended above the boom hem 1-6, resulting in the solid line position 11 in FIG.

In addition, FIG. 7 shows the connecting pin 9, the extending rod 20, the first and second links 30, 32, and the mounting pin 3 in that state.
J, 33, connection pin 34, etc. are schematically shown,
In this figure, in order to facilitate comparison with the telescopic boom A before contraction (Fig. 6), the position (horizontal direction) of the connecting pin 19 at the base of the overhanging rod 20 to the bracket la at the top of the outer boom 1 has been changed to the sixth position. Shown together with the figure.

Next, after connecting the right (top in FIG. 1) side support leg 12 of the jib 1 to the end of the support shaft 7 with another connecting pin 9, the extension rod 2
The U-shaped engaging portion 28 at the 0 end and the connecting pin 34 are engaged and released, but in order to release the engagement, the long holes 23, 23 of the connecting pieces 22, 22 of the base rod 21 and the end rod 24
If the connecting pin 29a is pulled out into the hole 26 of the connecting piece 25, the connecting pin 29 will fit into the long hole 23, 23 of the connecting piece 22, 22.
moves to the left side (Fig. 3), and the extending rod 2o bends as indicated by broken lines 21C and 24C in Fig. 2, and connects the connecting pin 3.
4 without pulling out the first and second links 30, 32.
The U-shaped engaging portion 2 at the end of the extending rod 34 remains connected.
8 and can be disengaged from it.

Note that after removing the mounting pin 31 at the base of the first rod 30 and rotating it around the connecting pin 34 and folding the first link 30 over the second link 32, the first and second links 30 and 32 are attached to the jib 1. It is stored in appropriate stages around the base of the cup.

Note that the base of the second link 30 and the base of the second link 32 are connected to the boom head 6 and the jib base by mounting pins 31, respectively.
．． If the structure is pre-installed according to 33, the first
The link 30 may be stored on the side of the boom head 6, and the second link 32 may be stored around the base of the jib by appropriate means.

Further, in this embodiment, the U-shaped engaging portion 2 of the end rod 24 is
8 (on the right side in FIG. 1), the connecting pin 34 is
An engaging pin 36 parallel to the first link 3 is provided, and the first link 3
A hook 37 is provided near the end of the hook 37.
is the engagement pin 36 of the end rod 24 when the inner boom 5 is extended (the outer boom 1 is in the one-point chain position as shown in FIG. 1 and the extension rod 20A is in a straight line, FIG. 6). is not engaged, and is at the protruding position of the protruding rod 20 (solid line positions 30, 32, 34 in Figures 1-7 and 7) or near the protruding position (double-dashed line in Rank W 30 B,
32B. When reaching 34B {+'7 position control), the first
The link 30 rotates significantly clockwise from the state shown in FIG. 6, and its hook 37 engages with the engagement pin 36 at the end of the overhang rod 20.

Therefore, at the end of the extrusion of the connecting pin 34 by the extending rod 20, or when the extension boom A is raised, the jib 11 will be swung outward beyond the button straight line passing through the connecting pin 9 at its base due to its own weight. In this case, if the overhang rod 20
This embodiment According to the first link 30
The inner side of the end hook 37 (on the left side in FIG. 7) abuts the right side of the engagement pin 36 of the end rod 24 of the extension rod 20, whose base is attached to the bracket 1a of the outer boom 1 with the connecting pin 19. contact and prevent its movement, which causes the first
A second link 32 connected to the link 30 with a connecting pin 34
The mounting pin 33, that is, the rotation of the jib 1-1 (support leg 12) around the connecting pin 9 is restricted.

Furthermore, the engaging pin 36 provided near the bottom wall of the U-shaped engaging portion 28 of the end rod 24 of the extending rod 20 and the hook 37 provided near the end of the l-th link 30 are If the angle between the extending rod 20 and the first link 30 is configured such that the jib 11 engages when it is in a range where it rotates around the connecting pin 9 due to its own weight, the dead weight of the extending jib 11, especially the The rotational inertia force at the end of the extension is the same as the hook 3.
7 and the engagement pin 36, the impact is distributed to the top side of the outer boom unit 24 and generated between the other side support leg 12 of the jib 11 and the other side of the boom head 6 at the end of the rising of the jib 11, etc. force is alleviated.

In addition, in this embodiment, the end lot 2 of the overhanging rod 20
Since the U-shaped engaging portion 28 is formed at the end of the boom head 6, the extending telescopic boom A of the boom head 6 can be contracted and the ends of the first and second links 30 and 32 After the U-shaped engaging portion 28 of the end rod 24 of the extending rod 20 is engaged with the connecting pin 34 to be connected, when the telescopic boom A is slightly extended and the jib l1 is folded to the side of the outer boom 1. , in accordance with the extension of the telescopic boob l1A, the shaft 7 on the boom head 6 moves in the same direction, and at the same time the mounting pin 31 of the first link 30 moves the same distance in the same direction, while the second link 32 moves in the same direction.
At the same time, the mounting pin 33 at the base moves in the same direction by the same distance, and the mounting pin 33 rotates around the connecting pin 9, thereby rotating the jib 1 counterclockwise (Fig. 1). , the second links 30 and 32 are opened to the left as shown in FIG. It does not engage with 36.

Therefore, in this case, even if the telescopic boom A is extended excessively, the hook 37 at the end of the first link 3o will hold the engaging pin 3 at the end of the end rod 24 of the extension rod 20.
6 is not destroyed, and its operation becomes easy.

(Effects of the Invention) Since the present invention has the configuration and functions as described above,
The following effects can be obtained.

(1) After rotatably connecting the base of the jib stored around the outer boom of the telescopic boom in the contracted state to an example of the boom head using a connecting pin, the innermost boom is slightly extended,
Next, the U-shaped engagement part of the end of the overhanging rod whose base is pivoted near the top of the outer boom is connected to the ends of the first link and second link whose bases are pivoted to the boom head and the support leg of the jib, respectively. The jib can be extended over the boom head by engaging the connecting pin of the section and then retracting the telescopic boom.

(2) After reducing the telescopic boom that extends from the jib above the boom head, attach the extension rod to the connecting pin of the first and second links.
- By engaging the U-shaped engaging portion at the end and then slightly extending the inner boom, the extending jib is bent and stored on the side of the outer boom, so when operating it, , even if the telescopic boom is extended excessively, the first and second
The connecting pin at the end of the link can be freely detached from the opening side of the U-shaped engagement portion of the overhang rod, and unreasonable tensile force etc. is applied to the first and second links, their connecting pins, the overhang rod, etc. This will not occur and there is no risk of destruction of the department.

(3) The extending rod of the jib is divided into the base rod 1 and the end rod, and a long hole is provided in one of the connecting pieces of both rods, and a pair of holes are provided at intervals in the other. A connecting pin fitted into one of the pair of holes is inserted into the elongated hole and rotatably connected, and the other hole and the elongated hole are connected by a removable connecting pin. By inserting and removing the rod, the extending rod is made straight or its effective length is reduced by bending, and the opening 27 of the U-shaped connecting portion is
By changing one direction, the first and second links can be engaged and disengaged from the connecting pin only by operating the overhanging rod, and the engagement and disengagement can be easily performed.

(4) The jib extension rod, first and second links, etc. are provided only on one side of the telescopic boom, and any of these rods or links extends from one side of the boom head to the other side beyond the same boom head. Since it does not extend to a length, the structure is simple and compact.

(5) The ends of the first and second links connect the supporting legs of the jib base to the side of the boom head with a connecting pin, and the bases are rotatably connected to the side of the boom head and the supporting legs of the jib, respectively. Since the connecting pin is engaged with the U-shaped engaging portion at the end of the extending rod, the jib can be easily extended, folded, and stored.

(6) Since the jib can be extended to the boom head of the telescopic boom by standing the telescopic boom up, it is possible to extend the jib onto the boom head of the telescopic boom, bend the extended jib, and extend it around the outer boom. Storing operations, etc. can be performed without requiring a large space unlike the conventional example.

[Brief explanation of drawings]

FIGS. 1 to 7 show an embodiment of an overhanging jib structure in a crane extension boom according to the present invention,
Figures 1 and 2 are schematic illustrations of the main parts, Figure 3 is an enlarged illustration of the connecting part of the jib extension rod, and Figures 4 and 5.
The figure shows a side view and a plan view of the end of the extension rod, and FIG. 6 shows the innermost boom slightly extended and the connecting pin of the second link and An explanatory diagram of their engagement relationship when the jib is engaged with the shape engagement part (or when the jib is folded to the side of the outer boom). Figure 7 shows the innermost boom reduced from the state shown in Figure 6. FIG. 8 is a side view of the main part of the extending jib structure in the extending boom of a conventional crane. The figure is an explanatory view of the operation in a state where the telescopic boom is slightly extended. A...Telescopic boom, 1...Outer boom,
5...Innermost boom, 6...Boom head, 9,]. 9, 29.33... Connecting pin, 12... Support leg, 20...
・Extrusion rod, 21...Base rod, 2
2, 25...Connection part, 23...Elongated hole,
24...End part 1~, 26...Elongated hole,
28...U-shaped engagement part, 29, 29a
...Connecting pin, 30...1st link, 32...2nd
Link, 36... Engagement pin, 37...
····hook.

Claims (3)

[Claims] (1) A jib is removably attached to the outer boom side of the telescopic boom, and one supporting leg of the jib is removably connected to the boom head side of the innermost boom in the contracted state of the telescopic boom using a connecting pin. At the same time, the base of the extension rod of the jib is rotatably connected to the vicinity of the top of the outer boom, and the base is rotatably connected to the boom head side of the innermost boom and the base of the jib, respectively. The ends of the first link and the second link, which are removably attached, are connected by a connecting pin, and the U-shaped engaging portion of the end of the extending rod is removably engaged with the connecting pin. An overhanging jib structure on the telescopic boom of a crane. (2) An engaging pin extending in the same direction as the connecting pin of the first and second links is provided slightly inside the U-shaped engaging portion at the end of the overhang rod, and near the end of the first link. The jib is characterized in that rotation of the jib is restricted by providing a hook and engaging the book with an engagement pin at the end of the extending rod at the end of extending the extending rod. An overhanging jib structure in a telescopic boom of a crane according to claim (1). (3) The extending rod of the jib is constituted by a base rod having a base connected with a connecting pin near the top of the outer boom, and an end rod having the U-shaped engagement portion at the end, and the base A long hole is provided in one of the connecting piece at the end of the rod and a connecting piece at the base of the end rod, and a pair of holes are provided at a required interval in the other, and the connecting piece is fitted into one of the pair of holes. In the telescopic boom of a crane according to claim (1), the connecting pin is always engaged with the elongated hole, and the connecting pin is removably inserted into the other hole and the elongated hole. Extrusion jib structure.