CRANE AND BOOM HOISTING DEVICE THEREOF

Abstract

A boom hoisting device comprising a mast having a pivotable front end portion connected to a front end portion of a boom through a guy line, a mast-side spreader provided at the front end portion of the mast, a frame-side spreader removably mounted to an upper rotating body and with a hoisting rope being stretched between and spread on both mast-side spreader and frame-side spreader, and a hoisting winch adapted to unwind and wind the hoisting rope to raise and lower the mast and the boom, the hoisting winch being mounted to the mast so that the mast and the hoisting winch are together removed from the upper rotating body by separation of a base end portion of the mast from the upper rotating body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are right side views of a crane having a boom hoisting device according to a first embodiment of the present invention, of which FIG. 1A shows the state of the crane just before removal of a mast and FIG. 1B shows the state of the crane after removal of the mast. Further, FIG. 1C shows the state of the mast after removal as seen in the same direction as the above right side views;

FIG. 2 is a right side view showing a crane having a boom hoisting device according to a second embodiment of the present invention;

FIGS. 3A and 3B are related to a hoisting winch shown in FIG. 2, of which FIG. 3A is a plan view showing an installed place of the hoisting winch and FIG. 3B is a right side view showing an installed place of the hoisting winch;

FIG. 4 is a right side view showing a crane having a mast as a boom hoisting device according to the related art; and

FIG. 5 is a right side view showing a crane having a gantry as a boom hoisting device according to the related art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described concretely hereinunder.

First Embodiment

A boom hoisting device according to this first embodiment of the present invention is of the type using a mast and its basic configuration is the same as that of the related art shown in FIG. 4 except that the layout of a winch for raising and lowering a boom and a mast is different, and therefore an explanation of the basic configuration will be omitted.

FIG. 1 is a right side view showing a crane having a boom hoisting device according to the first embodiment, in which FIG. 1A shows the state of the crane just before removal of a mast, FIG. 1B shows the state of the crane after removal of the mast, and FIG. 1C shows the state of the mast after removal. The same portions as in FIG. 4 are identified by the same reference numerals.

In this crane, as noted above, the layout of a hoisting winch 7 for raising and lowering a boom and a mast is different from that in the related art. That is, in the related art the hoisting winch 7 is installed on the rotating frame 3, but in this first embodiment it is installed directly on a mast 8.

The hoisting winch 7 has a drum 7a and a shaft 7b serving as a rotational center of the drum, both ends of the shaft 7b being supported rotatably by brackets (not shown) secured respectively to a pair of left and right frames which constitute the mast 8.

In a preparatory stage just before removal of the mast 8 in the crane of this configuration, as shown in FIG. 1A, a boom and a counterweight are removed from an upper rotating body 2 on a body frame and a guy line connected at both ends to the boom and the mast 8 is also removed, the mast 8 being brought down to the rear side. A frame-side spreader 10 (see FIG. 1C) is in a removed state from an upper rotating body 2. The timing for removal of the frame-side spreader 10 is not specially limited insofar as it is before removal of the mast 8.

After completion of such a preparatory work, a work for removing the mast 8 is performed. This work is done, for example, by lifting the mast 8 with another crane, not the crane related to the present invention, and removing it from the body frame. At this time the mast 8 and the hoisting winch 7 are together removed from the body frame as shown in FIG. 1C because the winch 7 is installed to the mast 8. This mast removing work can be done in a state in which the mast-side spreader 9 is connected to the mast 8 and the both mast-side spreader 9 and frame-side spreader 10 are connected together through a hoisting rope 12. Therefore, it is not necessary to pull out the hoisting rope 12 from both spreaders 9 and 10 and the mast 8 can be removed easily from the body frame. In this mast removing work it is preferable that both spreaders 9 and 10 be drawn close to each other by the hoisting winch 7 to make the frame-side spreader 10 difficult to shake during transport.

As to the form of the body frame when removing the mast 8, there are included an integrally combined state of both lower travel body 1 and upper rotating body 2 and a separated state thereof.

Second Embodiment

A boom hoisting device according to this second embodiment of the present invention uses both mast and gantry. According to a basic configuration thereof, a hoisting winch for raising and lowering both boom and mast is installed to the gantry.

A detailed description will be given below.

FIG. 2 is a right side view showing a crane having the boom hoisting device of this second embodiment, FIG. 3A is a plan view showing an installed place of a hoisting winch, and FIG. 3B is a right side view showing an installed place of a hoisting winch.

In this crane, a mast 40 is disposed behind a boom 4 and a gantry 41 is disposed behind the mast 40. The gantry 41 has a pair of right and left gantry compressing members 42 and a pair of right and left gantry pulling members 43, the gantry compressing members 42 and the gantry pulling members 43 being connected together at their front end portions to form a gantry top. The gantry 41 is configured so as to operate in the same way as the gantry 30 shown in FIG. 5 with a difference being recognized in only size.

As shown in FIGS. 3A and 3B, a hoisting winch 7 is installed the gantry 41 according to this second embodiment. On this regard, a description will now be given in detail. The hoisting winch 7 has a drum 7a and a shaft 7b serving as a rotational center of the drum. Both ends of the shaft 7b are supported rotatably by brackets 14 provided respectively in the pair of right and left gantry compressing members 42.

As shown in FIG. 2, a guy line 44 is connected between the mast 40 and the boom 4. A mast-side spreader 45 is connected to the mast 40 and a gantry-side spreader 46 is connected to the gantry 41. A hoisting rope 47 extending from the hoisting winch 7 mounted to the gantry 41 is spread on both spreaders 45 and 46. When the mast 40 is raised or lowered by the winch 7, the boom 4 connected to the mast 40 through the guy line 44 is raised or lowered.

Thus, in the boom hoisting device of this second embodiment, since the hoisting winch 7 is installed to the gantry 41, the hoisting winch 7 can be removed together with removal of the mast-side spreader 45 from the mast 40 and removal of the gantry 41 from the upper rotating body 2. In this way the gantry 41 can be removed easily from the body frame without the need of pulling out the hoisting rope 47 from both spreaders 45 and 46. In this gantry removing work, as noted earlier, it is preferable that the mast-side spreader 45 is drawn close to the gantry-side spreader 46 by the hoisting winch 7 to make the mast-side spreader 45 difficult to shake during transport. The mast 40 may be left removed or mounted in accordance with transport weight.

AS to the form of the body frame when removing the gantry 41 in this second embodiment, there are included an integrally combined state of both lower travel body 1 and upper rotating body 2 and a separated state thereof.

Although in the above second embodiment the raising/lowering winch 7 is installed on the gantry compressing member 42 side, the winch 7 may be installed on the gantry pulling member 43 side to the contrary.

Moreover, although in the above second embodiment the hoisting winch 7 is installed not on the mast 40 side but on the gantry 41 side, no limitation is made thereto. It goes without saying that the hoisting winch 7 may be installed on the mast 40 side and that the hoisting rope 47 from the hoisting winch 7 may be conducted to the gantry-side spreader 46.

Further, although in the above first and second embodiments a description has been given about a constructional example wherein the boom hoisting device has a mast or both mast and gantry, no limitation is made thereto, but the present invention is also applicable to a boom hoisting device having a gantry with a mast omitted.

In this case, there may be adopted a configuration wherein the gantry is installed on the upper rotating body removably and a hoisting winch is installed to the gantry. More specifically, there may be adopted a configuration wherein the hoisting winch 7 shown in FIG. 5 is installed to the gantry compressing member 31 or the gantry pulling member 32 of the gantry 30.

Although the invention has been described with reference to the preferred embodiments in the attached figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims.

Claims

1. A boom hoisting device of a crane, said boom hoisting device being mounted on a body frame of the crane having a boom capable of rising and lowering and causing the boom to rise and lower, said boom hoisting device comprising: a mast, said mast having a base end portion connected to said body frame removably and pivotably about an approximately horizontal axis and further having a pivotable front end portion connected to a front end portion of said boom through a guy line;a mast-side spreader provided at the front end portion of said mast;a frame-side spreader removably mounted on said body frame side, with a hoisting rope being stretched between and spread on both said frame-side spreader and said mast-side spreader; anda hoisting winch adapted to unwind and wind said hoisting rope to raise and lower said mast and said boom,wherein the hoisting winch is installed to said mast so that the mast and the hoisting winch are together removed from said body frame by separation of the base end portion of the mast from the body frame.

2. A crane having the boom hoisting device described in claim 1, comprising: a body frame;a boom mounted on said body frame so that it can rise and lower; anda guy line providing connection between a front end portion of said boom and the front end portion of said mast in said boom hoisting device,wherein the base end portion of said mast and said frame-side spreader in said boom hoisting device are mounted to said body frame removably.

3. A boom hoisting device of a crane, said boom hoisting device being mounted on a body frame of the crane having a boom capable of rising and lowering and causing said boom to rise and lower, said boom hoisting device comprising: a gantry connected to said body frame removably;a gantry-side spreader provided in said gantry;a guy line-side spreader provided at an opposite end of a guy line connected at one end to said boom or at a front end portion of a mast to which the opposite end of said guy line is connected, with a hoisting rope being stretched between and spread on said guy line-side spreader and said gantry-side spreader, anda hoisting winch adapted to unwind and wind said hoisting rope, thereby raising and lowering said boom,wherein said hoisting winch is installed to said gantry so that the gantry and the hoisting winch are together removed from said body frame by separation of the gantry from the body frame.

4. A crane having the boom hoisting device described in claim 3, comprising: a body frame;a boom mounted on said body frame so that it can rise and lower; anda guy line connected at one end thereof to a front end portion of said boom and with said guy line-side spreader in said boom hoisting device being provided at an opposite end of said guy line,wherein said gantry in said boom hoisting device is mounted to said body frame removably.