Hydraulic excavator

Abstract: There are provided a excavator body, a cabin provided on the upper surface, a work attachment mounted on the front part of said excavator body, and railings and roof supports forward of the cabin and rearward of a boom constituting the work attachment, the boom being arranged not to interfere with the roof supports in the whole rising and falling operating range over the whole swing operating range. Thereby, the maximum stand-up angle of he boom is enlarged to a specification angle, and the minimum rotating radius of the upper construction body including the work attachment is reduced to secure necessary railing function, enabling installation of a roof naturally in a minimum space.

Description: BACKGROUND OF THE INVENTION (FIELD OF THE INVENTION) The present invention relates to a compact hydraulic excavator. (DESCRIPTION OF THE RELATED ART) In the past, in the compact hydraulic excavator, an upper rotating body 2 is mounted on a crawler type traveling body 1 rotatably about a vertical axis, as shown in FIGS. 4 and 5. In an excavator body (a base machine) 3, a cabin 4 is provided in a central portion of the upper surface of the upper rotating body 2. The cabin 4 is provided downward of a seat with an engine and other machineries (not shown) and on both left and right sides with lever type operating devices 5, 5. Further, a handrail 6 is mounted forward of the cabin 4. A work attachment 7 is mounted directly forward of the handrail 6. The work attachment 7 is provided with a boom 8. In the standard specification (excavation specification), an arm 9 is mounted at the distal end of the boom 8, and a bucket 10 is mounted at the distal end of the arm 9. Reference numeral 11 denotes a boom cylinder for raising and lowering the boom 8. Numeral 12 denotes an arm cylinder for operating the arm 9. Numeral 13 denotes a bucket cylinder for operating the bucket 10. The boom 8 is mounted to be swung in a lateral direction about a vertical axis so that groove excavation work can be done easily. The boom 8 is driven by a swing cylinder 14. In the handrail 6, a front rail 6b is mounted horizontally and formed in an inverted U shape between vertical rails 6a, 6a on both left and right sides. The handrail 6 is used as a railing for supporting the body by hands when an operator leans forward to confirm the excavating part or when the operator gets on and off. However, according to the conventional hydraulic excavator of this kind, the front rail 6b of the handrail 6 interferes with the boom 8 in a stood upright state of the boom 8, as shown by the phantom outline in FIG. 4. Therefore, the maximum upright angle of the boom 8 is limited to an angle smaller than an original angle of the excavator (hereinafter referred to as a specification angle). This poses a problem that the minimum radius R1 of the turning circle of the upper construction body including the work attachment 7 increases. It is contemplated that the whole height of the handrail 6 be set to be low so as not to interfere with the boom 8. However, if so, the longitudinal rails 6a, 6a particularly often used are lowered, and the functionality as a railing means decreases. On the other hand, the compact excavator of this kind is normally not provided with a roof. However, it is desirable to install a roof from a viewpoint of securing safety at the work site. However, in this case, since there is no room for a space forward of the cabin, the vertical rails 6a, 6a of the handrail 6 are in the way so that it is difficult to install supports for a roof forward of the cabin. This is one obstacle for installing a roof. GB 2 184 419 A shows an excavator with a closed front cover (wire mesh) and a sun shade above an operator's seat. Between the sun shade and the front cover, there extends a transparent plate and forms a window screen. The sun shade is supported by a pair of rear support posts arranged rearward of the operators seat. SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic excavator having a compact design, wherein a safe and easy entry to the operator's seat is ensured. The hydraulic excavator according to the present invention comprises the features according to claim 1. 1) The maximum stand-up angle of the boom can be enlarged to a specification angle (a state of being projected rearward of both roof supports) to reduce the minimum rotating radius of an upper construction body. 2) Necessary railing function can be secured. 3) The roof can be installed in a minimum space. Further, the hydraulic excavator according to the present invention may have the following constitution: a frontal railing and connecting bar provided at an arrangement not to interfere with the boom between the roof supports. In this case, since a frontal railing and connecting bar provided at an arrangement not to interfere with the boom between the roof supports, both the railing function and the strength of the roof supports can be enhanced. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a hydraulic excavator according to an embodiment of the present invention; FIG. 2 is a front view of the same; FIG. 3 is a sectional view taken on A-A of FIG. 2; FIG. 4 is a side view of a conventional hydraulic excavator; and FIG. 5 is a plain view of the same. DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of the present invention will be described with reference to FIGS. 1 to 3. Only differences from the conventional hydraulic excavator shown in FIGS. 4 and 5 will be described. Railings and left and right front roof supports 15, 15, and left and right rear roof supports 16, 16 are stood upright on both left and right sides forward of a cabin 4 in an upper rotating body 2 of a excavator body 3, and on both left and right sides rearward of the cabin 4, respectively. A roof 17 for covering the cabin 4 from the top to protect an operator from falling things are mounted over the upper ends of the supports 15, 15, 16, 16. A boom 8 constituting a work attachment 7 swingable to the left and right is fixed centrally forward of the upper rotating body 2. Both roof supports 15, 15 are mounted so as not to interfere with the boom 8 during raising and lowering and at any swing position of the boom 8. A frontal railing and connecting bar 18 is mounted horizontally between both the front roof supports 15, 15. A handrail serving as a railing when one observes the a forward excavating area and gets in and out of the cabin (4) is constituted by both front roof supports 15, 15. The connecting bar 18 is mounted at a vertical position (a position closer to an intermediate lower part) not to interfere with the boom 8 in the whole operation range of the boom 8. According to this excavator constitution, the minimum rotating radius R2 of the upper rotating body including the work attachment 7 is reduced as compared with the minimum rotating radius R1 of the conventional excavator shown in FIGS. 4 and 5. Because the boom 8 is stood upright to a specified angle in a state not to interfere with the handrail (front roof supports 15, 15 and connecting bar 18) and being projected on the maximum and rearward (cabin 4 side) of both the roof supports 15, 15. Moreover, since both the roof supports 15, 15 can be used as a vertical railing also which is highly appreciated during operation and at the time of getting on and off, the railing function is not reduced compared to the conventional case where the height of the whole handrail is lowered. Further, it is not necessary to secure separate spaces for the roof supports and the longitudinal railing. Because of this, both of them can be installed naturally in the minimum space. Furthermore, a frontal railing and connecting bar 18 is provided at an arrangement not to interfere with the boom 8 between both roof supports 15, 15. Because of this, the railing function can be strengthened, and the strength of the roof supports 15, 15 can be increased. Preferably, the connecting bar 18 is provided between both the roof supports 15, 15 as in the above-described embodiment in order to enhance the railing function and the strength of the front roof supports 15, 15. However, the connecting bar 18 need not be provided, depending on the necessity. Further, needless to say, an arrangement falls under the scope of the present invention, in which a railing is separately mounted to a degree not to impair the desired function of the present invention.

Claims: A hydraulic excavator, comprising: an excavator body (2) provided with a travelling body (1), a cabin (4) provided on an upper surface of said excavator body (2), a work attachment (7) mounted on a front part of said excavator body (2), said work attachment (7) being provided with a boom (8) capable of being raised and lowered and capable of being swung on both left and right sides about a substantially vertical axis, roof supports (15) disposed forwardly of said cabin (4) and on both left and right sides rearwardly of said boom (8), said boom (8) being arranged not to interfere with said roof supports (15) in the whole operating range of said boom (8), when being fully raised and lowered and being fully swung to the left and to the right, a portion of said boom (8) projecting between said roof supports (15) and rearwardly of the plane defined by said roof supports (15) when said boom (8) is in a maximum stand-up state, said roof supports (15) forming a railing on either side of the excavator, and a roof (17) provided above said roof supports (15) to cover said cabin (4). The hydraulic excavator according to claim 1, further comprising a front railing and connecting bar (18) connecting the roof supports , wherein said connecting bar (18) is provided on said plane between said roof supports and below a position in which said boom (8) intersects the plane when in the boom (8) is in the maximum stand-up state.

Inventors: MATSUNAMI TOSHIHARU, MATSUNAMI, TOSHIHARU, Matsunami, Toshiharu, Shinko Engineering Co., Ltd.
Applicants: KOBELCO CONSTR MACHINERY LTD, KOBELCO CONSTRUCTION MACHINERY CO., LTD.
Application year: 2000
Main classification: E02F9
IPC codes: E02F9, E02F3