JPH0138140Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fall prevention device for a supplementary jib that is stored sideways in a wheel crane such as a truck crane or a rough terrain crane.

Conventionally, as shown in Japanese Utility Model Application No. 55-120679, for example, the jib was stored on the side of the boom when not in use, and when in use, it was swung out approximately 180 degrees to the side from this stored position and set in the extended position. In wheel-type cranes that use a method of
Moreover, the distal end portion is fixed by a fixing pin so that it cannot be moved forward, backward, left, or right.

To extend the jib, remove the fixing pin and swing the jib around the intermediate support point to the extension preparation position where one jib foot is aligned with the jib foot attachment boss at the tip of the boom. After the preliminary joining operation, extend the boom until the jib is released from the tip fixation, and then
A method is used in which the jib is swung out to the forward extended position using the pin connection point between the jib foot attachment portion and the jib foot as a fulcrum.

However, in the above-mentioned known technology, in the preliminary work stage for extending the jib, the jib can move forward from the time when the jib tip fixing pin is pulled out until one jib foot is pin-coupled to the jib foot mounting boss. The forward movement of the boom is stopped only by the frictional resistance at both the intermediate and tip support points of the jib, so depending on the inclination of the boom (including the inclination of the entire crane), vibrations etc. may occur. There was a danger that the jib would slide forward.

Such a problem also occurs at the jib swinging-back operation (preparatory storage operation), which is the opposite of the above-mentioned pre-extension operation when storing the jib, and a countermeasure for this problem has been desired in the sense of improving safety.

SUMMARY OF THE INVENTION The present invention provides a device for preventing a supplementary jib from falling off in a wheel-type crane, which eliminates the risk of the jib falling off due to forward slippage during the preliminary work stage of extending and storing the jib.

The present invention stores the replenishment jib on the side of the boom in a state in which the jib foot provided at the base end of the jib is spaced laterally from the jib foot attachment portion provided at the tip of the boom, and in this retracted position. After supporting the intermediate and distal ends of the jib on the boom and swinging the jib from this retracted position to a ready-to-extend position where the jib foot is aligned and connected to the jib foot attachment section, the jib foot and the jib foot attachment section are In a wheel crane that swings out to the side using a connection point as a fulcrum and extends to the tip of the boom, there is a jib intermediate support mechanism that rotatably supports the middle part of the jib around the vertical axis when the jib is stored, and a tip part of the jib. The jib tip support mechanism includes a locking body provided on the jib side and a locking body that is movably engaged between the retracted position and the extension preparation position. It consists of a bracket provided on the boom side so as to fit together, and a jib tip fixing pin that is inserted across the bracket and the locking body, and the bracket has an upper plate and a lower plate, and the lower plate has a A locking hole is provided in the upper plate, through which the jib end fixing pin is inserted in the jib storage position and fixes the locking body so that it cannot move in the front-rear and left-right directions. A long hole is provided through which the jib tip fixing pin is inserted and guides the locking body between the two positions.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a boom, and 2 is a supplementary jib (hereinafter simply referred to as a jib). Jib feet 3 and 4 are provided on both left and right sides of the base end of the jib 2, and a pair of upper and lower jib foot attachment bosses 5 and 6 are provided on both left and right sides of the tip end of the boom 1, respectively. Jib 2, when not in use,
As shown in FIGS. 1 and 2, the boom is stored along the left side surface of the boom with its tip facing toward the base end of the boom and with the left jib foot 3 positioned to the side of the left jib foot attachment boss 5. In this retracted position, the jib 2 is supported by the jib tip support mechanism 7 and the jib intermediate support mechanism 8 at two locations, the tip and the middle.
and is fixed in the front-rear and left-right directions by jib tip fixing pins 9 in the tip support mechanism 7.

When extending the jib, the jib 2 is held at the intermediate support point by the jib intermediate support mechanism 8 as a fulcrum.
As shown in Fig. 3, after the pre-stretching stage in which the left jib foot 3 is swung to the pre-extension position where it matches the left jib foot attachment boss 5 and these are connected with pins 10, the jib fixation is released by extending the boom (described later). Then, the jib 2 is swung out approximately 180 degrees forward from the side around the pin 10 so that it extends forward of the boom tip as shown in FIG.
Combine at 1.

Note that the boom 1 is normally constructed in a multi-stage telescoping type with a fixed boom at the base end and two or more stages of movable booms, but in order to make the explanation easier to understand, the boom 1 is This figure shows a one-stage telescopic configuration consisting of only a boom 1A and a tip boom 1B. On the other hand, the left-right direction here refers to the left-right direction as seen from the driver's seat. Furthermore, the left and right with respect to the jib 2 refer to the left and right when the jib 2 is in the extended state shown in FIG. 4.

The jib intermediate support mechanism 8 includes an intermediate locking body 1 provided on the left side surface of the intermediate jib in a shape of a horn protruding toward the tip end of the jib.
2, and a jib intermediate support bracket 13 provided on the left side surface of the intermediate portion of the base end boom 1A.
This bracket 13 is rotatably attached to the base end boom 1A via a bracket seat 14 around a vertical axis 15. Further, the bracket 13 is provided with an engagement hole 16 that penetrates in the boom axis direction, and the intermediate locking body 12 of the jib 2 is inserted into this engagement hole 16.
By inserting the jib 2 from the front, the intermediate part of the jib 2 is supported so as to be immovable in the left and right, up and down directions, and backward.

On the other hand, the tip support mechanism 7 includes a tip locking body 17 that is provided on the left side of the jib tip and protrudes in a shape of a horn toward the tip of the jib, similar to the intermediate locking body 12, and a tip locking body 17 on the left side of the base end of the base boom 1A. It is composed of the attached jib tip support bracket 18 and the jib tip fixing pin 9 described above. The bracket 18 is formed into a box shape with both front and back sides open.
The tip of the jib 2 is supported by inserting the tip locking body 17 into the jib 8 from the front like the intermediate locking body 12. Of the upper and lower plates 19 and 20 that make up the bracket 18, the lower plate 20 has a round hole into which the jib end fixing pin 9 is inserted so as not to be movable in the front, rear, left and right directions, as shown in FIGS. 6 and 7. Stop hole 2
1 is provided. On the other hand, the upper plate 19 has
In the jib swinging direction, more specifically, in the jib extending preliminary work stage shown in FIG.
A long hole 22 is provided along the swinging locus of the jib tip when the jib 2 is slightly swung out laterally using the fulcrum. Further, the tip locking body 17 is provided with a pin hole 23 for insertion of the fixing pin 9.

In the above configuration, when storing the jib, both the intermediate and tip locking bodies 12, 17 are inserted into the brackets 13, 18 from the front as described above, and the fixing pin 9 is inserted into the elongated hole of the bracket upper plate 19 in the tip support mechanism 7. 22, pin hole 23 of tip locking body 17;
It is inserted across the three retaining holes 21 of the lower plate 20. This allows the jib 2 to be moved forward, backward, left and right.
Fixed in the storage position without being able to move up or down.

Therefore, in the jib extending preliminary work stage shown in FIG.
In other words, when the jib tip is swung out slightly to the side using the vertical shaft 15 as a fulcrum, the jib tip fixing pin 9 is pulled up as shown by the imaginary line in FIG. 17 and the elongated hole 22 of the bracket upper plate 19. In this way, the pin 9 is made movable in the jib swinging direction within the range of the elongated hole 22 while remaining immovable in the longitudinal direction, and the jib 2 is swung out to the state shown in FIG. 3.

In this way, when using this device, the jib 2 can be preliminarily swung out while the jib 2 is prevented from moving forward by the jib tip fixing pin 9, so that the left jib foot 3 is attached to the left jib foot. Until it is connected to the boss 5 with the pin 10,
There is no risk of the jib 2 slipping forward.

Furthermore, after the pre-swinging is completed as shown in Fig. 3, the jib tip fixing pin 9 is completely removed and the tip boom 1B is extended.
forward and lock both the intermediate and tip locking bodies 12,1.
7 from brackets 13 and 18. After this, the jib 2 will be fully swung out centering on the left jib foot pin 10. Furthermore, the retracting operation of the jib 2 from the extended position is performed in the reverse order to the above. During this storage operation, after returning the jib 2 to the state shown in FIG. By inserting the jib tip fixing pin 9 into the elongated hole 22 and the pin hole 23 of the tip locking body 17 before removal, the jib 2 can be prevented from sliding forward. Moreover, this fixing pin 9 automatically enters the stopper hole 21 of the bracket lower plate 20 to fix the jib 2 when the jib swing-back is completed. This pin 9 retaining hole 21
In order to perform the automatic insertion action more reliably, a spring may be provided that always pushes the pin 9 downward (in the direction of the stopper hole 21), or the stopper hole 21 may be formed in a tapered shape that widens upward. good.

By the way, as another type of support for the jib tip, as shown in FIG.
4, and this locking body 24 is supported by being placed on the jib end support bracket 25 of the boom 1, and is fixed with a fixing pin 26. As a means for preventing the jib from falling off when such a jib tip support structure is adopted, a non-slip pin 27 is provided on the tip locking body 24 in a downwardly removable manner in addition to the jib tip fixing pin 26, and the pin 27 is attached to the bracket 2.
A known means is to prevent the jib 2 from slipping forward by locking the jib 5 from behind.

The present invention provides a jib tip support structure, in which the jib tip locking body is placed and supported on the boom side bracket, as an alternative to the anti-slip means using the falling-off prevention pin 27. Applicable. In the example shown in FIG. 8, the jib tip fixing pin 26 is inserted from above, that is, from the tip locking body 24 side, contrary to the figure, and the upper plate 25 constituting the bracket 25 is inserted.
What is necessary is to provide the long hole 22 in a and the stop hole 21 in the lower plate 25b.

Further, the present invention can be implemented in the same manner as described above for a wheel type crane in which the jib 2 is stored on the right side of the boom 1.

As described above, according to the present invention, it is possible to reliably prevent the jib from slipping forward and falling off when the jib is swung out or swung back using the intermediate support mechanism as a fulcrum during the jib extension or retraction operation. Moreover, it has a simple and rational configuration in which the jib tip fixing pin and the hole in the bracket into which the pin is inserted are also used to prevent the jib from falling off, so the number of parts and costs do not increase unnecessarily, and the operation is easy. It is simple and has excellent practical effects.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the jib in a retracted state showing an embodiment of the present invention, FIG. 2 is a side view of the same, FIG. 3 is a plan view of the jib in a preliminary stage of extension, and FIG. 4 is a plan view of the jib in a fully extended state. Fig. 5 is an enlarged plan view of the jib tip support mechanism, Fig. 6 is an enlarged sectional view along the line shown in Fig. 5, Fig. 7 is an enlarged sectional view taken along the same line, and Fig. 8 is another jib tip to which the present invention is applicable. FIG. 3 is a side view showing a support mechanism and a jib fall-off prevention means. 1...Boom, 2...Jib, 7...Jib tip support mechanism, 8...Jib tip support mechanism, 9...Jib tip fixing pin, 17...Jib tip support mechanism locking body,
18...the same bracket, 19...the upper plate of the same bracket, 20...the same lower plate, 21...
...stop hole, 22...long hole.

Claims (1)

[Scope of utility model registration request] The replenishment jib is stored on the side of the boom with the jib foot provided at the base end of the jib separated laterally from the jib foot attachment section provided at the tip of the boom, and in this retracted position, the middle part of the jib is and the leading end of the jib is supported on the boom, and the jib is swung from this retracted position to an extended preparation position where the jib foot is aligned and connected to the jib foot attachment part, and then
In the wheel-type crane that swings out laterally using the connection point between the jib foot and the jib foot attachment part as a fulcrum and extends to the tip of the boom, the jib intermediate support mechanism rotatably supports the intermediate part of the jib around the vertical axis when the jib is stored. , a jib tip support mechanism that supports the tip of the jib, and the jib tip support mechanism includes a locking body provided on the jib side, and a locking body that moves between the storage position and the extending preparation position. It consists of a bracket provided on the boom side so as to be movably engaged between the two, and a jib end fixing pin inserted across the bracket and the locking body, and the bracket has an upper plate and a lower plate. The lower plate is provided with a locking hole through which the jib end fixing pin is inserted when the jib is in the retracted position, and fixes the locking body so that it cannot move in the front-back and left-right directions. A device for preventing falling off of a supplementary jib in a wheel-type crane, characterized in that a long hole is provided through the jib tip fixing pin and the jib end fixing pin through the extending preparation position and the elongated hole for guiding the movement of the locking body between the two positions.