JPS6122950Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a telescopic boom type crane with an auxiliary jib, and more particularly, to a mounting structure for the auxiliary jib of such a telescopic boom type crane with an auxiliary jib.

Conventionally, this type of telescopic boom crane
It was common to use a horizontal jib type crane in which the auxiliary jib was stored sideways on the side of the telescopic boom. The auxiliary jib must be rotated at the tip of the telescopic boom, which requires a fairly large working space, and when the auxiliary jib is used for building work in the back of an alley, it is difficult to turn the auxiliary jib after the work is finished. When attempting to store the auxiliary jib, there was a problem in that the necessary work space for storing the auxiliary jib could not be secured, making the work extremely difficult. In order to solve this problem with the jib side-carrying type crane, the auxiliary jib is telescopically inserted into the telescopic boom, and during jib work, the auxiliary jib can be pulled out from within the telescopic boom in the boom extension direction and used. A telescopic boom crane with an internal jib system has already been developed, but in this conventional telescopic boom crane with an internal jib system, the auxiliary jib cannot be used during normal crane operations (during non-jib operations). Because the auxiliary jib was stored inside the telescopic boom while being fixed to the end boom, and the lifting work was carried out while extending and contracting the auxiliary jib integrally with the end boom, the crane as a whole fell over due to the weight of the auxiliary jib. There was a problem in that the moment was large, and the lifting load was limited accordingly, resulting in a deterioration in the lifting ability of the crane.

In view of the above-mentioned problems with conventional telescopic boom type cranes with auxiliary jibs, the present invention aims to simplify the work of attaching and removing the auxiliary jib by inserting the auxiliary jib into the boom, and also reduces the overturning moment of the crane when the jib is not in use. The purpose of this crane is to provide a telescoping boom type crane with an auxiliary jib that can improve the lifting capacity by reducing the overall size of the crane. a second stage boom, and a hydraulic cylinder is arranged internally in an inverted manner between the base end boom and the second stage boom, and a cylinder head of the hydraulic cylinder and a base end of the second stage boom are connected to each other. an appropriate boom which is pivotally connected so that the second stage boom can be extended and contracted by the hydraulic cylinder, and the tip boom is stretched between the tip boom, the second step boom and the proximal boom; A telescoping boom type crane comprising a telescoping boom capable of simultaneously telescoping in conjunction with the telescoping movement of the second stage boom via a telescoping wire rope device, and an auxiliary jib attached to the telescoping boom. The jib can be stored in the second stage boom of the telescopic boom, and the auxiliary jib is shaped so as to surround the hydraulic cylinder in the state of being stored in the second stage boom, and the auxiliary jib is When in use, it is attached to the tip of the tip boom, and when it is stored, it is fixed within the second stage boom and to the base end side of the second stage boom. It is characterized by this.

The telescopic boom type crane with auxiliary jib of the present invention will be explained below based on the embodiment shown in the attached drawings. A boom truck crane Z is shown. This crane device
It has a hydraulic cylinder 8 for luffing and hoisting devices 9 and 10 for lifting a load.

Below, the configuration and operation of the telescopic boom 1 and the auxiliary jib 5, which are the gist of the present invention, will be explained in Figures 2 to 1.
This will be explained in detail with reference to FIG.

The telescopic boom 1 includes a base end boom 2 attached to the swivel base 7 side as shown in FIG.
A three-stage telescopic boom having a second stage boom 3 and a tip boom 4 that can be extended and contracted against the
The base end portion 2a of the base end boom 2 and the base end portion 3a of the second stage boom 3 are inserted into the telescopic boom 1.
The hydraulic cylinder 6 placed between the
By extending and retracting the step boom 3 relative to the base boom 2, the tip boom 4 is connected to the second step boom 3 via a boom extension/contraction wire rope device U stretched between the base boom 2 and the tip boom 4. At the same time, it can be expanded and contracted (Fig. 5,
(See Figure 7). That is, as shown in FIG. 2, the boom extension/retraction wire rope device U connects the cable end pin 63 provided at the tip 2b of the proximal boom 2 via the front sheave 65 attached to the tip 3b of the second stage boom 3. Equalizer 64 provided at the base end 4a of the tip boom 4
Boom extension wire rope 61 stretched between
and a cable end pin 67 provided at the proximal end 4a of the tip boom 4 via a rear sheave 68 provided at the proximal end 3a of the second stage boom 3, and an equalizer provided at the tip 2b of the proximal boom 2. When the hydraulic cylinder 6 is extended to extend the second stage boom 3, the front sheave 65 acts as a kind of movable pulley to extend the boom. When the front end boom 4 is linked to the second stage boom 3 and the second stage boom 3 is extended simultaneously using the wire rope 61, and conversely, when the second stage boom 3 is contracted by contracting the hydraulic cylinder 6, the rear sheave 68 is extended at the same time. The boom retracting wire rope 62 acts as a movable pulley to move the tip boom 4 to the second stage boom 3 and simultaneously retract it.

In addition, the lengths of the tip boom 4 and the second boom stage 3 of this telescopic boom 1 are appropriately set so that, in the stored state, the base end face 4c of the tip boom 4 is located an appropriate distance toward the boom tip side from the base end face 3c of the second boom stage 3. The rear sheave 68 of the boom telescopic wire rope device U is attached to the base end 3a of the second boom stage 3 located toward the boom base end side from the end face 4c of the tip boom 4.
A pad plate 27 having approximately the same height as the upper surface of the lower flange plate 97 of the tip boom 4 is attached to the lower flange plate 94 of the boom 6. This pad plate 27 acts as a guide plate for the travel of the lower guide rollers 71, 71 attached to the auxiliary jib 5, which will be described later. A stopper 26 is attached to the boom base end side end 27a of this pad plate 27, which acts to stop the auxiliary jib 5 accurately at a specified storage position, as will be described later.
The second boom 3 has a base end 3a and a trunnion pin 40 at its cylinder head 6a.
The hydraulic cylinder 6 is a so-called tip trunnion type hydraulic cylinder supported by a trunnion rod and inserted into the telescopic boom 1 with its cylinder tail portion 6b facing the tip of the telescopic boom 1. A cylinder centering device W, which will be described later, is attached to the cylinder tail portion 6b of the hydraulic cylinder 6.

The auxiliary jib 5 is shown in FIGS. 2 and 12 to 1.
As shown in Figure 5, it is a plate structure jib formed with a rectangular cross section, and its length extends from the base end 3a of the second stage boom 3 of the telescopic boom 1 in the fully retracted state to the front end 4b of the tip boom 4. It has approximately the same length as the length in the boom extension direction, and its cross-sectional dimension is such that it can be inserted into the tip boom 4. This auxiliary jib 5 includes upper guide rollers 70, 70 and lower guide rollers 71, 71 provided on the upper and lower surfaces of the base end 5a, and the tip boom 4.
The tip side guide rollers 72, 72 provided on the lower surface of the tip portion 4b of the auxiliary jib 5 allow the boom to run freely in the extension direction, and the handle members 75, 75 provided on the tip portion 5b of the auxiliary jib 5 can be held by hand. By pushing and pulling the auxiliary jib 5, the auxiliary jib 5 can be easily pulled out from inside the telescopic boom 1 (Fig. 9).
(Figure 2).
Note that this pushing operation of the auxiliary jib 5 can also be performed using hoisting devices 9 and 10 for lifting a load. Also, of the upper guide rollers 70, 70 and the lower guide rollers 71, 71, the lower guide rollers 71, 71 are arranged close to the lower end surface 5c of the base end 5a of the auxiliary jib 5, and On the other hand, the upper guide rollers 70, 70 are the lower guide rollers 71,
71 by an appropriate distance toward the tip end of the jib, and is overlapped with the base end 4a of the tip boom 4 in the jib axial direction when the telescopic boom 1 is fully retracted.

In addition, the base end 5a of the auxiliary jib 5 is cut into a U-shape to have two end faces 5c and 5d in the vertical direction in order to avoid interference with the trunnion pin 40 of the hydraulic cylinder 6. 5d
is extended toward the base end of the boom by an appropriate dimension from the lower end surface 5c. The brackets 73, 73 of the lower guide rollers 71, 71 have their proximal end surfaces 73a, 73a aligned with the lower end surface 5 of the auxiliary jib 5.
c in the jib axial direction, and together with the lower end surface 5c, acts as a stopper member for positioning the auxiliary jib 5 as described later. Further, the upper end surface 5d functions as a posture control member of the cylinder alignment device W as described later.

This movement of the auxiliary jib 5 in the axial direction is controlled by the stopper 26 provided at the base end 3a of the second stage boom 3.
and a jib retaining device V, which will be described later, provided at the tip end 4b of the tip boom 4. That is, when the auxiliary jib 5 is pushed into the telescopic boom 1, it is stopped at the position where the lower end surface 5c of the base end 5a collides with the stopper 26 (the position shown in the third figure). At this time, the lower guide rollers 71, 71 of the auxiliary jib 5 are on the part plate 27, and the upper guide rollers 70, 70 are positioned close to the proximal end surface 4c of the tip boom 4. . Further, at this time, the tip end 5b of the auxiliary jib 5 is made to protrude slightly forward than the tip end 4b of the tip boom 4. This position of the auxiliary jib 5 is the retracted position of the auxiliary jib 5 with respect to the telescopic boom 1, and in this state, as shown in FIG.
5 and the boom proximal side pin receiving holes 16, 16 provided in the proximal end 3a of the second stage boom 3 are aligned, and both pin receiving holes 15, 1 are aligned with each other.
By inserting the jib fixing pin 42 into the telescopic boom 1 from the side of the telescopic boom 1, the auxiliary jib 5
will be fixed to the second stage boom 3 side.

On the other hand, the movement of the auxiliary jib 5 in the jib pull-out direction is regulated by the jib slip-off prevention device V. That is,
The jib retaining device V is connected to a spring 2 so as to always protrude into the tip boom 4 as shown in FIG.
Stopper pin 22 biased by 1
and an operating lever 23 that acts to forcibly retract the stopper pin 22. When the auxiliary jib 5 is retracted as shown in FIG.
Tip end stopper plate 3 installed at the appropriate location on the bottom of the
1 in the jib pull-out direction, and acts to prevent the auxiliary jib 5 from inadvertently moving toward the tip side from its storage position when the jib fixing pin 42 is removed. Also, by pushing down the operating lever 23 of this jib retaining device V to disengage the stopper pin 22 and the front end stopper plate 31, the auxiliary jib 5 is pulled forward from the telescopic boom 1 as shown in FIG. be able to. On the other hand, when the stopper pin 22 is released from the operating lever 23, the spring force of the spring 21 causes the stopper pin 22 to return to a predetermined position (the position where its tip protrudes into the tip boom 4). When the auxiliary jib 5 is pulled out to an appropriate position, the stopper pin 22 attaches one end 30 to the lower surface of the base end 5a of the auxiliary jib 5.
a extends from the proximal end surface 86a of the lower flange plate 86 toward the boom proximal end and engages with the pin receiving portion 30b of the proximal stopper plate 30 attached in the jib pull-out direction. It acts to regulate the maximum amount of pullout of the jib 5 to a certain amount.
The pulled-out position of the auxiliary jib 5 when the stopper pin 22 and the proximal stopper plate 30 are engaged becomes the mounting position of the auxiliary jib 5 when performing jib work using the auxiliary jib 5. In this state, as shown in FIG.
7 and 17, and the jib retaining pin 42 is inserted into both pin receiving holes 15 and 1 which are overlapped with each other.
5, 17, 17 by inserting it into the auxiliary jib 5.
is fixed to the tip end portion 4b of the tip boom 4. Also, at this time, the auxiliary jib 5 is in contact with the tip side guide rollers 72, 72 arranged on the lower surface of the tip portion 4b of the tip boom 4 and the upper flange plate 85 of the base end portion 5a of the auxiliary jib 5. It is supported in a slightly downwardly inclined state by the upper flange plate 96 of No. 4 to form an appropriate tilt angle.

Further, this telescopic boom 1 can freely extend and contract the telescopic boom 1 with the auxiliary jib 5 stored inside the telescopic boom 1, and normal crane work can be performed using only the telescopic boom 1. However, in this case, the tip boom 4 is apparently pulled forward from the auxiliary jib 5 fixed to the second stage boom 3 side, and the tip side guide on the tip boom 4 side The rollers 72, 72 will come off the lower surface of the auxiliary jib 5, but the tip side guide roller 7
2 and 72 are removed from the auxiliary jib 5, the tip side stopper plate 31 directly contacts the lower flange 97 of the tip boom 4 instead of the tip side guide rollers 72 and 72, and acts as a slide bush.

Further, as shown in FIG. 9, this telescopic boom 1 is attached to the upper flange plate 96 of the tip end 4b of the tip boom 4 at a position facing the upper guide rollers 70, 70 of the auxiliary jib 5 when the jib is attached, by adjusting the seam. A plate-shaped stopper 28 for preventing jib jumping is provided so that the distance between the upper guide rollers 70 and 70 can be adjusted as appropriate. An attempt is made to reduce the amount of jump as much as possible.

As shown in FIG. 18, the jib fixing pin 42 has a flat plate 44 of an appropriate length attached to one end 42a of the pin 42, with the plate 44 extending to one side. I am forced to insert it. In other words, when the jib is stored, Figs. 14 and 16
As shown in the figure, a proximal boom side pin insertion hole 47 consisting of a circular hole 50 formed in the side plate 92 of the proximal boom 2 and an elongated hole 53 extending upward from the circular hole 50, and a side plate 95 of the second stage boom 3. The second stage boom side pin insertion hole 48, which is made up of the formed circular hole 51 and an elongated hole 54 extending upward from the circular hole 51, is connected to the base end boom 2.
The boom base end side pin receiving holes 16, 16 formed in
It is made to match. Therefore, by aligning the stopper plate 44 with the elongated holes 53, 54 of each pin insertion hole 47, 48, the jib fixing pin 42 can be inserted from the outside of the telescopic boom 1 into each pin insertion hole 47, 48 and aligned with each other. The auxiliary jib 5 can be connected to the second stage boom side by fitting into the jib side pin receiving holes 15, 15 and the boom base end side pin receiving holes 16, 16. If the jib fixing pin 42 is released when the stopper plate 44 is inside the side plate 95 of the second stage boom 3, the jib fixing pin 42 will rotate due to the eccentric weight of the stopper plate 44 and move to the 14th stage boom 3. As shown in the figure, the stopper plate 44 stops in a downwardly hanging state. At this time, the stopper plate 44 engages with the side plate 95 of the second stage boom 3 in the direction in which the pin comes out, and acts as a member to prevent the jib fixing pin 42 from coming off. In addition, boom base end pin receiving hole 1
6 and 16 are formed on the side of pin support members 99 and 99 provided on the second stage boom 3. In addition, when the jib is installed, the side plate 8 of the tip boom 4 is attached to the boom head side plate 82 of the tip boom 4, as shown in FIGS.
Boom tip side pin receiving hole 17 formed in 8, 88,
A tip boom side pin insertion hole 49 is formed coaxially with the circular hole 52 and a long hole 55 extending upward from the circular hole 52, and the jib fixing pin 42 is inserted from the outside of the telescopic boom 1 through this pin insertion hole 49. boom tip side pin receiving holes 17 that are aligned with each other;
17 and jib side pin receiving holes 15, 1 to connect the auxiliary jib 5 to the tip boom 4 side. Also in this case, the stopper plate 44 of the jib fixing pin 42
acts as a retaining member for the jib fixing pin 42. The jib fixing pin 42 has a stopper plate 44 on one side of a straight cylindrical body 46 having an inner diameter into which the jib fixing pin 42 can be fitted, as shown in FIG.
The pin can be easily removed using the pin extracting tool 45, which has a square hole 57 of an appropriate size that can accommodate the pin in its axial direction, and a communication groove 58 that communicates the square hole 57 with one end 46a of the straight cylindrical body 46. .

As mentioned above, the hydraulic cylinder 6 is a trunnion-type cylinder at the tip, and when the jib is stored, it is inserted into the auxiliary jib 5, which has a small diameter as shown in FIG. 2, but when the jib is installed, it has a small diameter as shown in FIG. Since it is inserted into the large tip boom 4, the cylinder tail part 6b is always supported at the same height regardless of whether the jib is stored or installed, and the cylinder tail part 6b can be prevented from flying up due to vibrations caused by crane work. It is necessary to prevent an excessive bending load from acting on the rod portion by reducing the bending force. For this reason, in the illustrated embodiment, a cylinder alignment device W is attached to the cylinder tail portion 6b.

The cylinder alignment device W includes a cylinder support frame 33 of an appropriate length, which is protruded from the cylinder tail portion 6b and extends rearward from the cylinder tail portion 6b, as shown in FIGS. 5 to 7 and 10. ,
a lever member 35 pivotably supported by a fulcrum pin 34 provided on the axis _l1 of the hydraulic cylinder 6 at an axially intermediate portion of the cylinder support frame 33;
Both swinging ends 35a, 35b of the lever member 35
A supporting roller 36 for supporting the cylinder's own weight, a regulating roller 37 for regulating the lifting of the hydraulic cylinder 6, and a spring 38 that acts to bias the lever member 35 to one side are attached to each of the cylinders. have. Lever member 3
5 is always urged to rotate in the direction of arrow A by a spring 38 stretched between the lever member 35 and the cylinder support frame 33, and both sides 35c and 35d of the cylinder support frame 5 are connected to the cylinder support frame 33, respectively. The maximum inclination angle in the direction of arrow A-B is regulated by contacting stopper portions 33a and 33b provided at 33. The state in which the lever member 35 is tilted at the maximum angle in the direction of arrow A (the position indicated by the two-dot chain line 35'' in FIG. 10) is the rotational position of the lever member 35 when the jib is installed, and this is the first rotational position. Also, the state in which the lever member 35 is tilted at the maximum angle in the direction of arrow B (indicated by the solid line 35 in FIG. 10) is the rotational position of the lever member 35 when the jib is retracted, and this is referred to as the second rotational position. .Also, fulcrum pin 3
The relative positional relationship between the support roller 36 and the regulation roller 37 with respect to the roller 4 is set as follows depending on the rotational position of the lever member 35 (that is, the state of the auxiliary jib 5). That is, when the lever member 35 is in the first rotational position (i.e., when the jib is installed), the support roller 36 moves toward the fulcrum pin 3 as indicated by the chain line 36''.
The regulating roller 37 contacts the lower flange plate 97 of the tip boom 4 on a straight line _L2 hanging from the cylinder axis _L1 in a direction perpendicular to the cylinder axis L1, and the regulating roller 37 is moved slightly away from the upper flange plate 96 as shown by the chain line 37''. The fulcrum pin 3 is separated by the distance S ₁ .
4 at a predetermined height, and the lever member 35
is in the second rotation position (i.e., when the jib is retracted)
To do this, the fulcrum pin 34 is positioned at a predetermined height with the support roller 36 in contact with the lower flange plate 86 of the auxiliary jib 5 and the regulating roller 37 separated from the upper flange plate ₈₅ by an appropriate minute distance S2. is made possible. Note that when the auxiliary jib 5 is pulled out from the tip boom 4, this lever member 35 is returned from the second rotation position to the first rotation position by the spring force of the spring 38, and vice versa. When the lever member 35 is pushed into the tip boom 4, the lever member 35 is first pushed over its shoulder by the upper end surface 5d of the auxiliary jib 5 extending toward the proximal end, as shown by the reference numeral 5d' in FIG. The portion 35e is pressed and forcibly rotated in the direction of arrow B and returned to the position indicated by the reference numeral 35' in FIG. 10, and then the support roller 36 indicated by the chain line 36' in FIG. The auxiliary jib 5 is scooped up by the base end stopper plate 30 provided on the lower end surface 5c following the upper end surface 5d of the jib 5.
By being placed on the lower flange plate 86, it is returned to the second rotational position shown by the solid line.

Next, the operation method and function of the telescopic boom 1 and the auxiliary jib 5 of the illustrated embodiment will be explained.The auxiliary jib 5 is attached to and detached from the tip boom 4 when the telescopic boom 1 is fully retracted. That is, the auxiliary jib 5 stored in the telescopic boom 1 is moved to the tip boom 4.
When installing the auxiliary jib 5 and the second stage boom 3 in the state shown in FIGS. 2 and 5 (jib retracted state), At the same time, as shown in FIG. 11, the lever 23 of the jib retaining device V is pulled down from the position shown by the solid line to the position 23' shown by the chain line to engage the stopper pin 22 with the stopper plate 31 on the distal end side of the auxiliary jib 5. let go,
Thereafter, from the distal end side of the telescopic boom 1, the handle 75 provided on the distal end portion 5b of the auxiliary jib 5 is held by hand and the auxiliary jib 5 is pulled out in the axial direction. In addition, auxiliary jib 5
is pulled out to the tip side, and when the tip side stopper plate 31 passes the jib retaining device V, the operating force of the lever 23 is released to cause the stopper pin 22 to protrude into the tip boom 4.

The auxiliary jib 5 is supported by upper rollers 70, 70 and lower rollers 71, 71 provided on the auxiliary jib 5 side, and boom side rollers 72, 72 provided on the tip boom 4 side, and is supported by the second stage boom 3. base end 3a of
Because the butt 27 is provided, even though there is a step between the lower flange plate 97 of the tip boom 4 and the lower flange plate 94 of the second stage boom 3, the lower rollers 71, 71 can be moved to the second stage boom. It can be easily moved from side 3 to tip boom 4, and its pull-out or push-in operations do not generate impact noises (due to the lower rollers 71, 71 running up and down on steps), and can be performed with a small amount of operation. It can be done by force. In addition, at the initial stage of the jib pull-out operation, the auxiliary jib 5 is slid by the lower rollers 71, 71 and the boom-side rollers 72, 72, but as the auxiliary jib 5 is pulled out for a longer time, its center of gravity changes. From the time when the boom side rollers 72, 72 are moved forward, the base end 5 of the auxiliary jib 5
a is lifted up and now the boom side rollers 72, 72
and upper rollers 70, 70. When the auxiliary jib 5 is further pulled out and near the jib attachment position, the stopper pin 22 of the jib slip-off prevention device V engages the proximal stop provided at the base end 5a of the auxiliary jib 5, as shown in FIG. It engages with the pin receiving portion 30b of the par plate 30 in the jib pull-out direction, and the auxiliary jib 5 is stopped at that position. In this state, the pin receiving holes 15, 15 of the auxiliary jib 5 and the boom tip side pin receiving holes 17, 17 of the tip boom 4 are aligned, and both pin receiving holes 15, 15 are aligned with each other. ，
A jib fixing pin 42 is inserted into 17, 17 to connect the auxiliary jib 5 and the tip boom 4. This completes the work of attaching the auxiliary jib 5 to the tip boom 4 side (see Fig. 6). When the installation work of the auxiliary jib 5 is completed, the telescopic boom 1 is appropriately extended as shown in FIG. 8, and a predetermined jib work is performed.

On the other hand, when storing the auxiliary jib 5 inside the telescopic boom 1 after completing the jib work, first, the telescopic boom 1 is fully retracted, and then the tip boom 4 and the auxiliary jib 5 are
Then, the auxiliary jib 5 is pushed to a position where the lower end surface 5c of the base end 5a collides with the stopper 26 provided on the base end 2a of the base boom 2. At this time,
The lower end surface 5c of the auxiliary jib 5 is connected to the stopper 2.
6, the distal end stopper plate 31 of the auxiliary jib 5 forcibly pushes down the stopper pin 22 of the jib retaining device V, climbs over from the distal end to the proximal end, and engages with the stopper pin 22 in the jib withdrawal direction. Therefore, the jib retaining device V and the stopper 26 ensure that the jib is positioned at the retracted position. Furthermore, in this state, the pin receiving holes 15, 15 of the auxiliary jib 5 and the second
Since the pin receiving holes 16, 16 of the stage boom 3 match, the jib fixing pin 42 is inserted into the mutually matching pin receiving holes 15, 15, 16, 16, so that the auxiliary The jib 5 can be stored in the telescopic boom 1 while being fixed to the second stage boom 3 side.

Furthermore, this auxiliary jib 5 is fixed to the second stage boom 3 of the telescopic boom 1 when the jib is stored, but it is slidable relative to the tip boom 4, so that it can be kept in the stored state. Mama telescopic boom 1
When the auxiliary jib 5 is extended or contracted, the auxiliary jib 5 is displaced integrally with the second stage boom 3. Therefore, the auxiliary jib 5
The telescopic boom 1 can be freely extended and contracted with the telescopic boom 1 fixed to the second stage boom 3 side, and normal crane work can be performed using only the telescopic boom 1 (see Fig. 7).

Next, to explain the effects of the telescopic boom crane with auxiliary jib of the present invention, the telescopic boom crane with auxiliary jib of the present invention stores the auxiliary jib inside the telescopic boom, and when using the auxiliary jib, Since the auxiliary jib can be attached to the tip of the telescopic boom by pulling it out in the axial direction from the telescopic boom, it does not require a large work space for attaching and removing the auxiliary jib, unlike conventional cranes that carry the auxiliary jib sideways. Moreover, since there is no need to rotate the auxiliary jib, it is safe, and the work of attaching and detaching the auxiliary jib is greatly simplified, and the workability and operability are improved.

In addition, when the auxiliary jib is not in use, the auxiliary jib is fixed to the second stage boom located at the second stage from the tip of the telescopic boom, and is stored inside the telescopic boom, so that the second stage boom is moved as the telescopic boom expands and contracts. Since it is designed to be able to extend and contract together with the stage boom, the lifting load is increased by the reduction in the overturning moment due to the weight of the auxiliary jib compared to a crane in which the auxiliary jib is fixed to the tip boom side. This also has the effect of improving the lifting ability of the crane.

Furthermore, the auxiliary jib can be stored in the telescopic boom so as to surround the hydraulic cylinder when the jib is not in use. This has the practical effect that the cross-sectional shape of the auxiliary jib can be made larger than in the case where the auxiliary jib is made larger, and its cross-sectional performance can be improved, and its lifting ability can be improved.

[Brief explanation of the drawing]

Fig. 1 is an overall view of a telescopic boom type truck crane with an auxiliary jib according to an embodiment of the present invention, Fig. 2 is a vertical sectional view of the telescopic boom and auxiliary jib of the truck crane of Fig. Figure 4 is an enlarged view of the part shown in Figure 2, Figures 5 to 8 are views of the telescopic boom and auxiliary jib in the telescopic state shown in Figure 2, and Figure 9 is an enlarged detail of the part shown in Figure 8. Figure 10 is an enlarged detailed view of Figure 5, Figure 11 is a detailed view of Figure 4.
12 is a view taken along arrows XII-XII of FIG. 4, FIG. 13 is a vertical sectional view of FIG. 9, FIG. The figure is a -longitudinal sectional view of Figure 3, and Figure 16 is the -longitudinal cross-sectional view of Figure 1.
4, FIG. 17 is a view taken along the arrow in FIG. 13, and FIG. 18 is a perspective view of the jib fixing pin and its removal tool shown in FIG. 13. 1... Telescopic boom, 2... Base end boom, 3... Second stage boom, 3a... Base end of second stage boom, 4... Tip boom, 5... Auxiliary jib, 6... Hydraulic cylinder, 6a
...Cylinder head of hydraulic cylinder, U...Wire rope device for boom extension and contraction.

Claims (1)

[Scope of utility model registration request] It has a tip boom 4 and a second stage boom 3 that extend and contract with respect to the base end boom 2, and a hydraulic cylinder 6 is internally disposed in an inverted manner between the base end boom 2 and the second stage boom 3. The cylinder head portion 6a of the hydraulic cylinder 6 and the base end portion 3a of the second stage boom 3 are pivotally connected so that the second stage boom 3 can be extended and contracted by the hydraulic cylinder 6,
The distal end boom 4 is connected to the telescopic movement of the second stage boom 3 via an appropriate boom telescoping wire rope device U stretched between the distal end boom 4, the second stage boom 3, and the base end boom 2. A telescoping boom 1 that can be simultaneously extended and contracted in conjunction with each other, and the telescoping boom 1
A telescopic boom type crane with an auxiliary jib, the crane having an auxiliary jib 5 attached to the auxiliary jib 5.
can be stored in the second-stage boom 3 of the telescopic boom 1, and has a shape such that the auxiliary jib 5 also surrounds the hydraulic cylinder 6 when stored in the second-stage boom 3, The auxiliary jib 5
is attached to the tip of the tip boom 4 when in use, and fixed within the second stage boom 3 and on the base end 3a side of the second stage boom 3 when stored. A telescopic boom type crane with an auxiliary jib, characterized in that it is designed to be