JPS6234948Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a crane such as a truck crane that has a jib on its boom, and particularly to a jib device for extending and folding the jib.

Cranes such as truck cranes are generally equipped with a jib. This jib is extended to the tip of the boom when in use, and can supplement the boom length mentioned above, expanding the working range of the crane and ensuring a high lifting height for the lifted load. It is. On the other hand, when not in use, the jib is folded along the underside of the boom and placed on the underside or side of the boom, so that it does not interfere with crane operations using only the boom.

By the way, in the case of such a jib, it is desirable to make its length as long as possible in order to expand the above-mentioned working range and lifting height. However, if the jib is made too long, there will be a problem that the tip of the jib will come into contact with the undulation cylinder that makes the undulation of the boom during folding. For this reason, the length of the jib is limited to the length from the tip of the boom to the tip of the luffing cylinder, and there has been a problem that a longer length cannot be secured.

This invention was made based on these circumstances, and its purpose is to provide a crane jib device that can secure a sufficient length of the jib without interfering with the hoisting cylinder. It is in.

That is, in this invention, shafts are provided protruding from both sides of the tip of the boom, and the jib is rotated around the shaft with both fork recesses provided at the base end of the jib fitted to these shafts. Therefore, in a jib device that extends and folds a jib, one of the fork recesses is fitted and attached to the base end of the jib so that it can expand and contract, and by extending this fork recess, the jib is attached to the bottom surface of the boom. The jib is folded along the center line of the boom and deviated to one side from the center line of the boom, thereby making the length of the jib longer than the length from the tip of the boom to the connection position of the luffing cylinder to the boom. It is something to do.

An embodiment of this invention will be described below with reference to FIGS. 1 to 7.

Figure 1 shows a truck crane, 1 is the car body,
2 is a swivel base, 3 is an extendable boom, 4 is a lifting cylinder of this boom 3, 5 is a driver's cab for traveling, and 6 is a driver's cab for crane work.

A jib 7 is stored in the lower surface of the boom 3, and the jib 7 is detachably supported by supports 8 and 9 attached to the lower surface of the boom 3. Note that 10 is a stop for the auxiliary wire 11 for the jib 7, and 12 is a guide for the auxiliary wire 11 as well.

The tip end 3a of the boom 3 has shafts 13 and 14 protruding from both sides thereof, and these shafts 13 and 14 are used for extending and storing the jib 7. That is, jib 7
The base end portion of the jib 7 is configured such that the distal end portion 3a of the boom 3 can be loosely fitted thereinto, and fork recesses 15 and 16 are provided at both base ends of the jib 7, respectively.
These fork recesses 15 and 16 form the shafts 13 and 1.
4, respectively. Therefore, with the fork recesses 15 and 16 fitted to these shafts 13 and 14, the shafts 13 and
By rotating the jib 7 around 14, the jib 7
It can be extended and folded. Note that 17 is a sheave for a single rope at the tip of the boom 3.

In addition, for example, retaining pins 18 and 19 can be attached to the fork recesses 15 and 16 as retainers. These retaining pins 18,
19 are removably inserted into pin holes 20, 21 formed in the fork recesses 15, 16, thereby preventing the shafts 13, 14 from coming off when the jib 7 rotates.

In this embodiment, one of the fork recesses 1
5 is extendable and retractable with respect to the base end 7a of the boom 7. That is, as shown in FIGS. 3 to 6, a fork recess 15 is provided at the base end 7a of the boom 7.
A mounting hole 22 is formed, and this mounting hole 22
The insertion portion 15a of the fork recess 15 can be telescopically inserted into the fork recess 15. In addition, the insertion portion 15a
A long hole 15b is formed along the longitudinal direction of the boom 7, and a pin hole 23, which is spaced apart from each other in the longitudinal direction, is formed on the side surface of the base end 7a of the boom 7.
24 is formed. Therefore, by inserting the holding pin 25 through the long hole 22 into one of these pin holes 23 and 24, the fork recess 15 can be fixed.

The other fork recess 16 is integrally formed with the base end 7b of the boom 7, and has the same structure as the conventional one.

Next, the operation of one embodiment with the above configuration will be explained. When extending and folding the jib 7, first fit the fork recesses 15 and 16 of the jib 7 into the respective shafts 13 and 14, and insert the retaining pins 18 and 19 into the pin holes 20 and 21, respectively. to prevent these shafts 13 and 14 from coming off,
At this time, one of the fork recesses 15 is held in an extended state. That is, the fork recess 15 is pulled out from the mounting hole 22 at the base end of the boom 7, and the holding pin 25 is inserted into one pin hole 23 to maintain its extended state. Therefore,
In this state, one of the fork recesses 15 is in an extended state, so the jib 7 is inclined obliquely with respect to the axis of the boom 3, and as a result, the jib 7 is rotated around the axes 13 and 14. When the jib 7 is rotated and folded, the jib 7 can be tilted and folded as shown in FIGS. 2 and 3. Therefore, as is clear from FIG. 2, even if the jib 7 is long, the tip side of the jib 7 does not come into contact with the undulation cylinder 4, and can be folded while avoiding the undulation cylinder 4. As a result, jib 7
This allows a sufficient length to be secured, and the work performance of the crane can be greatly improved.

Further, when the jib 7 is extended from the folded state, the holding pin 25 of the fork recess 15 is replaced with the other pin hole 24 and the fork recess 15 is contracted. The jib 7 can be extended in a straight position.

Furthermore, since the jib 7 is stored diagonally, the tip of the jib 7 can be positioned above the bottom surface of the boom 3, as shown in FIG. It also has the advantage of improving visibility.

Note that this invention is not limited to the above embodiment. For example, in the above embodiment, the jib device of a truck crane was explained, but the application is not limited to truck cranes, but can also be applied to vehicle-type cranes that have a dual-purpose operator's cab for both crane work and traveling, and can also be applied to tower cranes, etc. It is also applicable to various cranes equipped with jibs.

As explained above, this design has shafts protruding from both sides of the tip of the boom, and the jib is rotated around the shafts with both fork recesses provided at the base end of the jib fitted to these shafts. In this jib device, in which the jib is extended and folded, one of the fork recesses is fitted and attached to the base end of the jib so that it can expand and contract. Therefore, when folding the jib, one of the fork recesses is extended to tilt the jib, and in this tilted position the jib can be folded onto the underside of the boom. Therefore, interference with the luffing cylinder can be avoided, so that a sufficient length of the jib can be ensured and the performance of the crane can be improved.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention; Fig. 1 is a side view of the truck crane, Fig. 2 is a bottom view of the boom, Fig. 3 is an enlarged view showing a partially sectional view of the middle part of Fig. 2, and Fig. 4 is a side view of the truck crane. The figure is a side view with a partial cross section showing the middle part of Figure 3, Figure 5 is a bottom view with a partial cross section showing the tip of the boom when the jib is extended, and Figure 6 is a partial cross section of the middle part of Figure 5. FIG. 7 is a side view of the jib in an extended state. 3...Boom, 4...Luffing cylinder, 7...Jib, 13, 14...Shaft, 15, 16...Fork recess, 18, 19... Retaining pin (retainer).

Claims (1)

[Scope of utility model registration request] Shafts are provided protruding from both sides of the tip of the boom that is raised and lowered by the hoisting cylinder, and a fork recess that can be fitted to the shaft is provided at the base end of the jib, and the shaft is inserted into both of these fork recesses. A detachable retainer is provided to prevent the jib from coming off, and by rotating the jib around the above-mentioned axis, the jib is extended to the tip side of the boom and folded along the bottom surface of the boom. When folded along the lower surface, in a crane jib device in which the tip of the jib has a length extending toward the proximal end of the boom beyond the connection position of the hoisting cylinder to the boom, one of the fork recesses is attached to the jib. When the jib is fitted and attached to the base end so as to be extendable and retractable, and the jib is folded onto the bottom surface of the boom, the tip of the jib is deviated to one side from the center line of the boom due to the extension of the one fork recess. A crane jib device characterized by: