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Excavator

Excavator description/claims

1. Field of the Invention

The present invention relates to an excavator provided with a function of preventing contact between a bucket and a cabin.

2. Description of the Related Art

A description will particularly be given taking an offset type hydraulic excavator in which contact between a cabin and a working attachment is easily generated as an example (FIGS. 5 to 7).

In the hydraulic excavator, a working attachment 3 is installed in a front section of an upper rotating body 2 mounted on a crawler type lower traveling body 1.

The working attachment 3 is provided with a boom 5 to be raised and lowered taking a boom foot pin 4 as a center, an arm 7 attached to a front end of the boom 5 pivotally around a boom top pin 6 in the up and down direction, and a bucket 9 attached to a front end of the arm 7 pivotally around an arm top pin 8 in the up and down direction. By raising, lowering and bending actions of the working attachment 3, various works such as excavating and loading are performed.

The boom 5 is formed by a rear boom 5a and a front boom (also called an offset boom) 5b. By turn movement of the front boom 5b in the left and right direction to the rear boom 5a, the arm 7 and the bucket 9 are horizontally moved in the left and right direction (offset) so that an excavating work for ditch or the like is performed. FIG. 6 shows a state that an offset action is performed to the left side, and the symbol α is an offset angle thereof.

In FIGS. 5 and 6, the reference numeral 10 denotes a boom raising and lowering cylinder for raising and lowering the boom 5, the reference numeral 11 denotes an arm cylinder for turning the arm 7 in the up and down direction, the reference numeral 12 denotes a bucket cylinder for turning the bucket 9 in the up and down direction, and the reference numeral 13 denotes an offset cylinder for turning the front boom 5a in the left and right direction.

In the upper rotating body 2, a cabin 14 is installed on one of the left and right sides in a front section thereof (generally on the left side in the front section as shown in the figure, hereinafter a description will be given with the above configuration). Various operations are performed within the cabin 14.

By a dozer 15 (not shown in FIG. 6) provided in a front section of the lower traveling body 1, a ground leveling work and a dustpan work with using the bucket 9 are performed.

Here, since the working attachment 3 is bent towards the cabin 14 side, contact between the bucket 9 and the cabin 14 may be generated. Particularly, in the exemplified offset type excavator, since the bucket 9 is located in front of the cabin 14 in the state that an offset action is performed to the left side as shown in FIG. 6, the contact is highly possibly generated.

Meanwhile, there is a contact prevention method disclosed in Japanese Patent Laid-Open No. Hei3-156037.

In FIG. 7 schematically showing the entire excavator, a contact area A serving as an area where the contact between the bucket 9 and the cabin 14 may be generated when the arm top pin 8 intrudes is set in front of the cabin 14. When the arm top pin 8 enters the above contact area A, attachment actions (generally actions of boom raising, arm pulling and left offset) are stopped.

The contact area A is set in the vicinity of the cabin 14 shown by a double chain line in FIG. 7 in a general attachment with the bucket 9 having standard size and being directly attached to the front end of the arm.

Meanwhile, in the case where the bucket size is larger than standard, and in the case where the bucket 9 is attached to the front end of the arm through a special bucket attachment device for simplifying an attaching and detaching work called quick hitch or the like (hereinafter, such an attachment is collectively referred to as the special attachment), a distance from the arm top pin 8 to a tooth top of the bucket is longer than the standard attachment.

In the case of having the above special attachment, a special contact area B which is broader than the standard contact area A towards the front side shown by a broken line in FIG. 7 is set, and when the arm top pin 8 intrudes the above area B, the attachment actions are stopped.

However, as shown in FIG. 7, a front limitation position of the bucket in a state that the bucket 9 is grounded (a position where the bucket is stopped by a contact prevention function) is displaced towards the front side. Therefore, there is a problem that a work of excavating, soil scooping and the like near a front end of the lower traveling body 1 (hereinafter, referred to as the near-by work) is limited.

Since the tooth top of the bucket 9 in the above figure does not reach the dozer 15, it is not possible to perform the so-called dustpan work of drawing the soil or the like to the dozer 15 side and scooping by the bucket 9, which is a type of the near-by work. The symbol B in FIG. 7 denotes a distance from the tooth top of the bucket to a front surface of the dozer.

It should be noted that even in an excavator not performing the offset action, in the case of installing the special attachment in which bucket width is large and there is a fear that the left side of the bucket may be brought in contact with the cabin 14, the same problem is caused.

It is an object of the present invention to provide an excavator capable of sufficiently ensuring the near-by work described above while avoiding contact between a bucket and a cabin as much as possible in the case where the special contact area is set.

An excavator according to the present invention comprises a lower traveling body, an upper rotating body mounted on the lower traveling body and provided with a cabin, and a working attachment installed in a front section of the upper rotating body as a basic configuration. The above working attachment is provided with a boom to be raised and lowered, an arm attached to a front end of the boom pivotally around a boom top pin, and a bucket attached to a front end of the arm pivotally around an arm top pin. Further, the excavator according to the present invention is provided with position detecting means for detecting a position of the arm top pin, and control means for executing a contact prevention function of limiting actions of the working attachment when the arm top pin intrudes a contact area preliminarily set in front of the cabin. Here, the control means is to set, in a corner part formed by an area front surface serving as a front limitation of the contact area and an area lower surface serving as a lower limit of the contact area, an exception area of a right triangle seen from the side taking the area front surface as a vertical side and the area lower surface as the base under the following condition, and to cancel the contact prevention function when the arm top pin is within the exception area.

• Provisional Patent
• Utility Patent

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