Excavator

Abstract

In a corner part on the front and lower side of a contact area between a bucket and a cabin 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 is set under a fixed condition. When an arm top pin is within the above exception area, a contact prevention function is cancelled and actions of boom raising, arm pulling and left offset are permitted in a decelerating state.

1 . An excavator, comprising:
 a lower traveling body;   an upper rotating body mounted on said lower traveling body, the upper rotating body being provided with a cabin;   a working attachment installed in a front section of said upper rotating body, the working attachment being 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;   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 said working attachment when the arm top pin intrudes a contact area preliminarily set in front of the cabin, wherein   said 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,   the condition for setting the exception area:   in the case where there is not the exception area mentioned above, an x-coordinate position where the arm top pin is stopped by the contact prevention function at the time of grounding and horizontally moving the bucket to the rear side is made as a first point, an y-coordinate position determined by adding a maximum value for an increasing amount of a distance from a land surface to be grounded to the arm top pin in accordance with bucket size or the like to an y-coordinate position at the time of stopping the arm top pin at the first point is made as a second point, an x-coordinate position determined by adding a distance from a tooth top of the bucket to a target point set behind the first point to an x-coordinate position at the time of stopping the arm top pin at the first point is made as a third point, and a right triangle area connecting the points mentioned above is made as an exception area.   
   
   
       2 . The excavator according to  claim 1 , wherein
 said working attachment is capable of performing an offset action towards the cabin side.   
   
   
       3 . The excavator according to  claim 1 , wherein
 a dozer is provided in a front section of said lower traveling body, and taking a front surface of the dozer as a target point, an x-coordinate position determined by adding a distance from the tooth top of the bucket to the dozer to the x-coordinate position at the time of stopping the arm top pin at the first point is made as the third point so as to set the exception area.   
   
   
       4 . The excavator according to  claim 1 , wherein
 when the arm top pin is within the exception area, the actions of the working attachment are decelerated.   
   
   
       5 . The excavator according to  claim 1 , wherein
 when the arm top pin is within the exception area, an alarm is operated.