EP0943578A2

EP0943578A2 - Crane

Info

Publication number: EP0943578A2
Application number: EP99105550A
Authority: EP
Inventors: Hiroshi c/o Okubo Plant in Kobe Steel Miyazawa
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 1998-03-19
Filing date: 1999-03-18
Publication date: 1999-09-22
Also published as: JPH11263591A; EP0943578A3; JP3436118B2; KR19990077947A; KR100301942B1

Abstract

A fleet angle of a rope is suppressed to be small while employing a side drum type in which a winch drum is installed sideway of a boom. A drum arranging plane A which is a plane perpendicular to a drum shaft 6a passing through an axial center point Wo of a winch drum shaft 6a is inclined with respect to a boom moving plane so that a rope contact of a main guide sheave 8 includes two points P1 and P2 formed on a boom moving plane B by the raising and lowering of a boom 2.

Description

BACKGROUND OF THE INVENTION

Field of the Invention:

The present invention relates to a crane in which a hoisting winch drum is installed on a rotating frame of an upper rotating body.

Description of the Related Art:

It is well known in the past that mainly in a wheel type crane, a side drum type is employed in which a hoisting winch drum is installed sideway of a boom base portion in a rotating frame.
In the case where the side drum type as described is employed, a winch drum is greatly offset laterally with respect to a boom point sheave provided on the extreme end portion of the boom, and therefore, when a hoisting rope drawn out from the winch drum is directly guided to the boom point sheave, a fleet angle becomes excessively large whereby the random winding and the disengagement of the rope from the sheave often occur, and the life of the rope lowers.
Because of this, in the case where the side drum type is employed an intermediate guide sheave is provided between the winch drum and the boom point sheave. However, in only this arrangement, the fleet angle between the winch drum and the intermediate guide sheave or between the intermediate guide sheave and the boom point sheave cannot be made sufficiently small.
In view of the foregoing, the technique is developed in which a winch drum is inclined (for example, in the case where a winch drum is arranged on the left side of a boom, the left side of the drum is inclined to assume a position forward of the right side as viewed in plane) as viewed in plane so that the end on the boom side is positioned closer to the base end of the boom than the end on the opposite side, as disclosed in Japanese Utility Model Application Laid-Open No. 3-64986, Japanese Patent Application Laid-Open No. 7-267583, and so on.
However, the above-described constitution still has the following problem.
A contact between a guide sheave and a rope to be a fleet angle support point is moved on a circular arc locus on the boom moving plane by the raising or lowering operation of the boom.
On the other hand, by mere inclination of the winch drum as viewed in plane, as described above, the arranging plane of the winch drum, that is, the plane perpendicular to the drum shaft passing through an axial center point of the drum shaft merely crosses at one point at maximum with respect to the circular arc locus. Therefore, the fleet angle becomes large in the range deviated from the crossing point.
That is, the range in which the fleet angle is large still leaves widely, and the problem of the lowering of the rope life cannot be solved sufficiently.

SUMMARY OF THE INVENTION

The present invention therefore provides a crane in which a fleet angle of a rope can be suppressed to be small while employing the side drum type.
The first invention provides a crane wherein a boom is provided to be raised and lowered about a boom foot pin on a rotating frame of an upper rotating body mounted on a lower travel body whereas a winch drum is installed sideway of the boom in the rotating frame, and a hoisting rope drawn out of the winch drum is let pass through a boom point sheave provided on an extreme end portion of the boom and hung down from the extreme end portion of the boom, characterized in that a rope guide means located between the winch drum and the boom point sheave to guide the hoisting rope is provided on the upper surface in the lowered state of the boom, and the winch drum is provided so that
(1) the end on the boom side is inclined as viewed in plane assumes a position closer to the base end of the boom than the end on the opposite side, and
(2) the end on the boom side is inclined as viewed in back assumes a position lower than the base end on the boom side.
The second invention provides a crane wherein a boom is provided to be raised and lowered about a boom foot pin on a rotating frame of an upper rotating body mounted on a lower travel body whereas a winch drum is installed sideway of the boom in the rotating frame, and a hoisting rope drawn out of the winch drum is let pass through a boom point sheave provided on an extreme end portion of the boom and hung down from the extreme end portion of the boom, characterized in that a rope guide means located between the winch drum and the boom point sheave to guide the hoisting rope is provided on the upper surface in the lowered state of the boom, and the winch drum is provided under the following conditions:
let A be a drum arranging plane which is a plane perpendicular to the drum shaft passing through the axial intermediate portion of the winch drum shaft, and
let P1 and P2 be two points on a circular arc locus formed on a boom moving plane B by the raising or lowering of the boom, the two points being rope contacts as a fleet angle support point in which the hoisting rope comes in contact with the rope guide means,
then, the drum arranging plane A is inclined with respect to the boom moving plane B so as to substantially include the two points P1 and P2.
The "axial intermediate portion of the drum" termed herein includes not only an intermediate point in a strict sense but also a position somewhat deviated from the intermediate point in a limit not impairing the operation and effect of the second invention.
Further, the "substantially include the two points P1 and P2" termed herein means to include not only the case of completely including but also the case of not completely including in a limit not impairing the operation and effect.
In the third invention according to the first or second invention, as the rope guide means, a horizontal guide sheave to be horizontal in a boom horizontal state is provided.
In the fourth invention according to any of the first to third invention, an auxiliary rope guide means for guiding a hoisting rope drawn out of the winch drum to the upper surface of the boom between the rope guide means and the winch is provided on a rotating frame.
In the fifth invention according to the fourth invention, as the auxiliary rope guide means, an auxiliary rope guide sheave is provided rotatably about a sheave shaft substantially parallel to a drum shaft.
In the sixth invention according to the fifth invention, the auxiliary rope guide sheave is supported axially slidably on the sheave shaft .
In the seventh invention according to the fifth or sixth invention, the auxiliary rope guide sheave is arranged so that the contact of the hoisting rope with the sheave is superposed to a boom foot pin as viewed in side.
According to the above-described constitution, the following operation can be achieved.
The boom moving plane is a vertical surface parallel to the boom shaft, whereas the drum arranging plane can be expressed by an angle as viewed in back  X and an angle as viewed in plane  Y. A crossing line between the boom moving plane and the drum arranging plane (a straight line joining crossing points together) can be expressed by Y=aX+b.
On the boom moving plane, the supporting point of the fleet angle is moved while forming a circular arc locus by the raising and lowering of the boom. The crossing point between the locus and the above equation is a point which can make the fleet angle smallest, and the fleet angle becomes large as the fleet angle supporting point moves away from the crossing point.
That is, in the constitution described in Japanese Patent application Laid-Open No. 7-267583 and so on merely provided with an inclination as viewed in plane, the crossing line is a vertical line (X, 0), and the crossing point is limited to one point at maximum under this condition.
On the other hand, in the present invention, the winch drum is inclined not only as viewed in plane but also as viewed in back (in the second invention, the drum is inclined so that the fleet angle supporting point substantially includes two points on the circular arc locus) whereby the crossing line is a line inclined parallel to the circular arc chord, and the crossing points can be made two points at maximum.
Accordingly, it is possible to secure wide range of the boom angle that can make the fleet angle small.
According to the second invention, the fleet angle is minimum at two points P1 and P2 on the circular arc locus formed by the rope contact in the rope guide means (guide sheave).
Therefore, the positions of the two points P1 and P2, that is, the bilateral inclination angles of the winch drum are set so that the change of the fleet angle is made as small as possible through all the range of raising angle of the boom to thereby suppress the absolute value of the fleet angle to be small.
Further, in the case where operation is carried out merely at a limited angle, or in the case where there is an angle that is used often, the fleet angle can be set to be minimum at these boom angles.
Therefore, it is possible to prevent an occurrence of random winding of the hoisting rope by the winch drum and possible to extend the life of the rope.
Further, according to the fourth invention, the auxiliary rope guide is interposed between the winch drum and the rope guide means whereby the hoisting rope can be wound about the winch drum in a stable manner, and drawn out of the drum.
In this case, (i) the fifth invention in which the auxiliary rope guide sheave as the auxiliary rope guide means is provided rotatably about the sheave shaft substantially parallel with the drum axis, and (ii) the sixth invention in which the guide sheave is arranged slidably in an axial direction are employed, or these inventions are combined whereby more stabilized rope winding and drawing-out operation can be obtained, and therefore the random winding preventive effect becomes higher.
Further, according to the seventh invention in which the same sheave is arranged so that the rope contact with respect to the auxiliary rope guide sheave is superposed to the boom foot pin as viewed in side, the rope length ahead of the sheave does not change due to the raising or lowering of the boom.
Therefore, the boom can be raised and lowered while the hook hung and supported on the hoisting rope is stored and secured to the extreme end of the boom.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the present invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description when taken into conjunction with the accompanying drawings wherein:
FIG. 1 is a plan view of a boom, a winch and so on showing an embodiment of the present invention;
FIG. 2 is a partly enlarged side view of a boom, a winch and so on showing the embodiment of the present invention;
FIG. 3 is a back view in a state of a boom angle shown by the phantom line of FIG. 2;
FIG. 4 is a view showing a boom and so on as viewed both in plan and side for explaining a relationship between a drum arrangement plane and a boom moving plane;
FIG. 5 is an enlarged view of FIG. 4 for explaining the maximum fleet angle when a boom angle is 0° ;
FIG. 6 is a view corresponding to FIG. 5 for explaining the maximum fleet angle when a boom angle is 12.01° ; and
FIG. 7 is a view corresponding to FIG. 5 for explaining the maximum fleet angle when a boom angle is 40° .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1 to 3, reference numeral 1 designates a rotating frame of an upper rotating body mounted on a lower travel body not shown, and reference numeral 2 designates a boom mounted on the rotating frame 1 so as to be raised and lowered about a boom foot pin 3.
The boom 2 is expansively constituted by a fixed boom 2a and a plurality of movable booms 2b, and a boom point sheave 4 is provided on the extreme end portion of the movable boom 2b.
A hoisting rope 7 drawn out of a drum 6 (only the drum 6 in a winch 5 is shown in FIGS. 2 and 3) of the winch 5 is guided downward from the extreme end of the boom by the point sheave 4, and a hook not shown is hung and supported by the rope 7.
The winch 5 including the winch drum 6 is installed on the rotating frame 1 at a position deviated rearward and on one of left and right sides (on the right side as viewed from the proximal end of the boom in the drawing, which will be explained below) with respect to the boom 2.
In the drawings, reference numeral 6a designates a winch drum shaft as a rotating center shaft of the winch drum 6, and in FIG. 1, Wo designates an axial center of the winch drum shaft 6a.
Accordingly, the winch drum 6 is in a state of being greatly deviated in position rightward and downward with respect to the boom point sheave 4, in which case, the hoisting rope 7 can not be guided to the boom point sheave 4 directly from the winch drum 6.
A main guide sheave 8 is mounted rotatably about a sheave shaft 8a to be vertical in a horizontal state of the boom on the upper surface at the extreme end portion of the fixed boom 2a, and an auxiliary guide sheave 9 is mounted on the rotating frame 1 above the winch drum 6 so as to cover:
(1) a lateral deviated portion of the winch drum 6 and the boom point sheave 4 by the main guide sheave 8, and
(2) a vertical deviated portion of the winch drum 6 and the boom point sheave 4 by the main auxiliary guide sheave 9.
As shown in FIGS. 1 to 3, (a) the auxiliary guide sheave 9 is mounted slidably in an axial direction with respect to a sheave shaft 9a in a state in which (b) the sheave shaft 9a is substantially parallel with the winch drum shaft 6a (completely parallel or almost parallel), and (c) a contact with the hoisting rope 7 is superposed to the boom foot pin 3 as viewed from side.
By the provision of the constitutions (a) and (b) as mentioned above, the auxiliary guide sheave 9 moves so as to assume a position on a straight line joining a drawing-out point with the main guide sheave 8 in response to the axial movement of the rope drawing-out point from the winch drum 6, and therefore the stable rope guiding operation is secured.
Further, by the provision of the constitution (c) as mentioned above, the length of the rope ahead (the extreme end side of the boom) from the contact of the hoisting rope 7 with the auxiliary guide sheave 9 rarely changes due to the raising or lowering of the boom, and therefore, the boom 2 can be raised and lowered while the hook is stored in and secured to the extreme end portion of the boom.
On the other hand, the winch drum 6 is installed on the rotating frame 1 in a state being inclined bilaterally with respect to the axis parallel with the boom foot pin 3 so that the end on the right side (the side opposite to the boom 2) as viewed in plane is positioned forward of the left side (on the boom 2 side) and the right side of the drum is positioned upward of the left side as viewed in back. In FIG. 1, Y designates an inclination angle as viewed in plane, and in FIG. 3, X designates an inclination angle as viewed in back.
In the illustrated preferred embodiment of the present invention, as shown in FIG. 4,
(i) let A be a drum arranging plane which is a plane perpendicular to the drum shaft 6a passing through the axial center point Wo of the winch drum shaft 6a, and
(ii) let P1 and P2 be two points on a circular arc locus C formed on a boom moving plane B by the raising or lowering of the boom 2,

winch drum

By this arrangement of the drum, a straight line (a crossing line) L in which the boom moving plane B and the winch arranging plane A intersect is inclined with respect to a vertical axis Lv. The winch arranging plane A includes the two points P1, P2 and the center point Wo in an axial direction of the drum.
Note that the boom moving plane B is a surface parallel with a boom length axis passing through the rope contact in the main guide sheave 8.
On the other hand, the drum arranging plane A includes the case of completely including the two points P1 and P2 and the case of not completely including them in a limit which exhibits the equal operation and effect. The plane A includes not only the case of passing through the center point Wo in an axial direction of the drum in a strict sense but also the case being somewhat deviated from the center point Wo.
With the above constitution, the fleet angle of the rope 7 between both the main and auxiliary guide sheaves 8 and 9 is minimum at the two points P1 and P2 on the circular arc locus C formed by the rope contact by the inclinations (bilateral inclination) of the drum arranging plane A as viewed in plane and as viewed in back.
Accordingly, the absolute value of the fleet angle can be suppressed to be small through all the range of the boom raising angle by setting the positions of the two points P1 and P2, that is, the bilateral inclination angles X and Y of the drum arranging plane A so that the change of the fleet angle is as small as possible through all the range of raising angle (0° to 80°) of the boom 2.
A concrete example will be explained with reference to FIGS. 5 to 7. In the case where the inclination angles X and Y of the winch drum 6 are set so that the boom angle when the rope contact reaches the crossing point P1 is 12.01° and the boom angle when the rope contact reaches the crossing point P2 is 67.2° ,
a) at the boom angle 0°, the maximum fleet angle  is 1.82° (see FIG. 5),
b) at the boom angle 12.01° (crossing point P1), the maximum fleet angle  is 1.3° (see FIG. 6),
c) at the boom angle 40° (intermediate angle), the maximum fleet angle  is 1.82° (see FIG. 7),
d) at the boom angle 67.2° (crossing point P2), the maximum fleet angle  is 1.3°, and
e) at the boom angle 80° (maximum angle), the maximum fleet angle  is 1.82°, and the maximum fleet angle  can be suppressed within 2° which is a standardized value on laws and ordinances through all the range of boom raising angle.
α in FIGS. 5 to 7 indicates the maximum displacement in an axial direction of the rope drawing-out point in the winch drum 6 in each boom angle state.
The above-described setting is an example, and the boom angles of the crossing points P1 and P2 can be changed variously other than those mentioned above.
Further, in the case where operation is carried out merely at a limited boom angle, or in the case where there is a boom angle that is often used, it is possible to set that at these angles, the maximum fleet angle  is minimum.
While in the above-described embodiment, the main guide sheave 8 is provided to be horizontal in a boom horizontal state, it is to be noted that the same sheave 8 can be provided to be vertical in a boom horizontal state (the sheave shaft 8a is horizontal).
On the other hand, it is desired that in order to wind and draw-out the hoisting rope 7 on the winch drum 6 in a stable manner, the auxiliary guide sheave 9 is provided as in the above-described embodiment. However, the present invention can be applied, for example, to the case where the winch drum 6 is installed substantially at the same height as the boom foot pin 3 whereby the rope 7 is guided directly to the main guide sheave 8 from the winch drum 6 without using the sheave 9.
As described above, according to the present invention, the winch drum is inclined not only as viewed in plane but also as viewed in side (in the second invention, the winch drum is inclined so that the fleet angle crossing point substantially includes two points on the circular arc locus), whereby the crossing line is a line inclined parallel to a circular arc chord, and the crossing points can be two at maximum.
Accordingly, it is possible to secure wide boom angle range that can make the fleet angle small.
Particularly, with the construction of the second invention, the drum arranging plane is inclined with respect to the boom moving plane so that the rope contact includes two points P1 and P2 on the circular arc locus formed on the boom moving plane. Therefore, the positions of the two points P1 and P2, that is, the bilateral inclination angles of the winch drum are set so that the change of the fleet angle is made as small as possible through all the range of raising angle of the boom to thereby suppress the absolute value of the fleet angle to be small.
Further, in the case where operation is carried out merely at a limited angle, or in the case where there is an angle that is used often, the fleet angle can be set to be minimum at these boom angles.
Therefore, it is possible to prevent an occurrence of random winding of the hoisting rope by the winch drum and possible to extend the life of the rope.
Further, according to the fourth invention, the auxiliary rope guide is interposed between the winch drum and the rope guide means whereby the hoisting rope can be wound about the winch drum in a stable manner, and drawn out of the drum.
In this case, (i) the fifth invention in which the auxiliary rope guide sheave as the auxiliary rope guide means is provided rotatably about the sheave shaft substantially parallel with the drum axis, and (ii) the sixth invention in which the guide sheave is arranged slidably in an axial direction are employed, or these inventions are combined whereby more stabilized rope winding and drawing-out operation can be obtained, and therefore the random winding preventive effect becomes higher.
Further, according to the seventh invention in which the same sheave is arranged so that the rope contact with respect to the auxiliary rope guide sheave is superposed to the boom foot pin as viewed in side, the rope length ahead of the sheave does not change due to the raising or lowering of the boom.
Therefore, the boom can be raised and lowered while the hook hung and supported on the hoisting rope is stored and secured to the extreme end of the boom.
A fleet angle of a rope is suppressed to be small while employing a side drum type in which a winch drum is installed sideway of a boom. A drum arranging plane A which is a plane perpendicular to a drum shaft 6a passing through an axial center point Wo of a winch drum shaft 6a is inclined with respect to a boom moving plane so that a rope contact of a main guide sheave 8 includes two points P1 and P2 formed on a boom moving plane B by the raising and lowering of a boom 2.

Claims

A crane wherein a boom is provided to be raised and lowered about a boom foot pin on a rotating frame of an upper rotating body mounted on a lower travel body whereas a winch drum is installed sideway of the boom in the rotating frame, and a hoisting rope drawn out of the winch drum is let pass through a boom point sheave provided on an extreme end portion of the boom and hung down from the extreme end portion of the boom, characterized in that a rope guide means located between the winch drum and the boom point sheave to guide the hoisting rope is provided on the upper surface in the lowered state of the boom, and the winch drum is provided so that

(1) the end on the boom side is inclined as viewed in plane assumes a position closer to the base end of the boom than the end on the opposite side, and

(2) the end on the boom side is inclined as viewed in back assumes a position lower than the base end on the boom side.
A crane wherein a boom is provided to be raised and lowered about a boom foot pin on a rotating frame of an upper rotating body mounted on a lower travel body whereas a winch drum is installed sideway of the boom in the rotating frame, and a hoisting rope drawn out of the winch drum is let pass through a boom point sheave provided on an extreme end portion of the boom and hung down from the extreme end portion of the boom, characterized in that a rope guide means located between the winch drum and the boom point sheave to guide the hoisting rope is provided on the upper surface in the lowered state of the boom, and the winch drum is provided under the following conditions:

let A be a drum arranging plane which is a plane perpendicular to the drum shaft passing through the axial intermediate portion of the winch drum shaft, and

let P1 and P2 be two points on a circular arc locus formed on a boom moving plane B by the raising or lowering of the boom, said two points being rope contacts as a fleet angle support point in which the hoisting rope comes in contact with the rope guide means,

then, the drum arranging plane A is inclined with respect to the boom moving plane B so as to substantially include the two points P1 and P2.
The crane according to claim 1 or 2, wherein as the rope guide means, a horizontal side sheave to be horizontal in a boom horizontal state is provided.
The crane according to any of claims 1 to 3, wherein an auxiliary rope guide means for guiding a hoisting rope drawn out of the winch drum to the upper surface of the boom between the rope guide means and the winch is provided on a rotating frame.
The crane according to claim 4, wherein as the auxiliary rope guide means, an auxiliary rope guide sheave is provided rotatably about a sheave shaft substantially parallel to a drum shaft.
The crane according to claim 5, wherein the auxiliary rope guide sheave is supported axially slidably on the sheave shaft.
The crane according to claim 5 or 6, wherein the auxiliary rope guide sheave is arranged so that the contact of the hoisting rope with said sheave is superposed to a boom foot pin as viewed in side.