Construction machine

Abstract

There is provided a construction machine that achieves both safety and operability by lowering the possibility of an accident due to contact between the construction machine and a worker in the periphery of a vehicle body while securing operability in situations where an object required for work is present in the periphery. A controller has a normal mode as a control mode for making the operation limiting control effective and a temporary cancelation mode as a control mode for temporarily canceling the operation limiting control. The controller shifts to the temporary cancelation mode in response to operation of the control canceling device while in the normal mode. The controller shifts back to the normal mode in a case where a predetermined condition not responsive to operation of the control canceling device is satisfied while in the temporary cancelation mode.

1 . A construction machine comprising:
 an actuator;   an operation device for instructing the actuator to operate:   an obstacle sensor for detecting an obstacle in a periphery of the construction machine;   a controller for performing operation limiting control to limit operation of the actuator in a case where the obstacle sensor detects an obstacle; and   a control canceling device for instructing the controller to cancel the operation limiting control;   wherein the controller is configured to have a normal mode as a control mode for making the operation limiting control effective and a temporary cancelation mode as a control mode for temporarily canceling the operation limiting control,   shift to the temporary cancelation mode in response to operation of the control canceling device while in the normal mode, and   shift back to the normal mode in a case where a predetermined condition not responsive to operation of the control canceling device is satisfied while in the temporary cancelation mode.   
     
     
         2 . The construction machine according to  claim 1 , further comprising:
 an operation lock device switchable between a locked position for inhibiting operation of the actuator and an unlocked position for permitting operation of the actuator,   wherein the predetermined condition includes switching of the operation lock device from the unlocked position to the locked position.   
     
     
         3 . The construction machine according to  claim 1 , wherein the predetermined condition includes continuation of a state in which the obstacle sensor does not detect an obstacle over a predetermined period of time. 
     
     
         4 . The construction machine according to  claim 1 , wherein the controller is further configured to have a permanent cancelation mode that is a control mode for permanently canceling operation limiting control,
 determine in the normal mode whether the controller is to shift to the temporary cancelation mode or the permanent cancelation mode depending on how the control canceling device is operated, and   shift, in the permanent cancelation mode, to the normal mode in response to operation of the control canceling device.   
     
     
         5 . The construction machine according to  claim 4 , wherein the control canceling device includes a momentary pushbutton switch,
 the controller is configured to shift to the temporary cancelation mode in a case where a continuously pressed time of the pushbutton switch is shorter than a predetermined period of time in the normal mode, and   shift to the permanent cancelation mode in a case where the continuously pressed time of the pushbutton switch is equal to or longer than the predetermined period of time in the normal mode.   
     
     
         6 . The construction machine according to  claim 1 , further comprising:
 an operation sensor for detecting whether the operation device is operated or not,   wherein the controller is configured to shift to the temporary cancelation mode if the operation sensor has detected operation of the operation device continuously over a predetermined period of time or longer while the obstacle sensor is detecting an obstacle, other than in response to operation of the control canceling device, in the normal mode.