Abstract: The present small swing type excavator is characterized by comprising an engine (81) disposed in the rear section of a rotating frame (8) in such a condition that the longitudinal direction thereof is directed to the lateral direction of the rotating frame (8), a hydraulic oil tank (82) disposed on one lateral side in front of the engine (81), a cabin (83) disposed on the other lateral side, an air conditioner (85) disposed under a floor (84) of the cabin (83) and having two surfaces facing to, respectively, the front side and the left outer side of the rotating frame (8), and a fuel tank (86) formed so as to be arranged along at least two surfaces of the front and left side surfaces of the air conditioner (85) and detachably attached to the rotating frame (8).

Abstract: The present invention provides a hydraulic excavator provided with a dozer device comprising an arm having a rear end connected to a fulcrum portion provided on a lower frame of a lower traveling body, a dozer blade provided at an extreme end of the arm, and a dozer cylinder for swinging the arm in vertical direction, characterized in that the dozer cylinder and the arm are arranged in a state of forming two sides of a triangle as viewed from the side, the arm swings vertically so that the dozer cylinder does not interfere with a bottom of an upper rotating body rotatably mounted on the lower traveling body, and an approach angle when the dozer blade vertically moved by the arm is placed in the highest position is set to 35 degrees or more, thereby capable of securing travelability equal to an excavator without a dozer device.

Abstract: In a construction machine having a working attachment, an operator's seat disposed on one side of a machine body, a devices receptacle portion disposed on the other side, and an operating member disposed sideways of the seat for operating the attachment, the machine is characterized in that a canopy comprises a front support post disposed in front of the seat, a rear support post disposed behind the seat, a side support post disposed sideways of the seat and on the side where an operator gets on and off the machine body, and a roof which connects the support posts with one another, the front support post being disposed close to the devices receptacle portion and the side support post being disposed outside the operating member to form an open portion obliquely in front of the seat where open portion is for ensuring a working vision for the attachment which is swung to the seat side.

Abstract: The present small swing type excavator is characterized by comprising an engine (81) disposed in the rear section of a rotating frame (8) in such a condition that the longitudinal direction thereof is directed to the lateral direction of the rotating frame (8), a hydraulic oil tank (82) disposed on one lateral side in front of the engine (81), a cabin (83) disposed on the other lateral side, an air conditioner (85) disposed under a floor (84) of the cabin (83) and having two surfaces facing to, respectively, the front side and the left outer side of the rotating frame (8), and a fuel tank (86) formed so as to be arranged along at least two surfaces of the front and left side surfaces of the air conditioner (85) and detachably attached to the rotating frame (8).

Abstract: The present invention provides a hydraulic excavator provided with a dozer device comprising an arm having a rear end connected to a fulcrum portion provided on a lower frame of a lower traveling body, a dozer blade provided at an extreme end of the arm, and a dozer cylinder for swinging the arm in vertical direction, characterized in that the dozer cylinder and the arm are arranged in a state of forming two sides of a triangle as viewed from the side, the arm swings vertically so that the dozer cylinder does not interfere with a bottom of an upper rotating body rotatably mounted on the lower traveling body, and an approach angle when the dozer blade vertically moved by the arm is placed in the highest position is set to 35 degrees or more, thereby capable of securing travelability equal to an excavator without a dozer device.

Abstract: In a construction machine having a working attachment, an operator's seat disposed on one side of a machine body, a devices receptacle portion disposed on the other side, and an operating member disposed sideways of the seat for operating the attachment, the machine is characterized in that a canopy comprises a front support post disposed in front of the seat, a rear support post disposed behind the seat, a side support post disposed sideways of the seat and on the side where an operator gets on and off the machine body, and a roof which connects the support posts with one another, the front support post being disposed close to the devices receptacle portion and the side support post being disposed outside the operating member to form an open portion obliquely in front of the seat where open portion is for ensuring a working vision for the attachment which is swung to the seat side.

Abstract: A control circuit for a construction machine using a control lever for revolving a boom swing in common with a traveling motor and switching pilot pressure via a switching valve has a switch for supplying a switching signal to the switching valve. A pressure switch detects whether the pilot pressure is output from a remote control valve or not. A switching control circuit switches a position of the switching valve to a position for the boom swing cylinder when the switching signal is output from the switch and holds the position of the switch at the position for the boom swing cylinder when the pilot pressure is detected by the pressure switch, to thereby prevent wrong operation in switching.

Abstract: The present invention is a control circuit for a construction machine for using a control lever for revolving and boom swing in common and switching pilot pressure via a switching valve, comprising: a switch for supplying a switching signal to the switching valve; a pressure switch for detecting whether the pilot pressure is output from a remote control valve or not; a switching control circuit for switching a position of switch to a position for a boom swing cylinder when the switching signal is output from the switch and holding the position of switch at the position for the boom swing cylinder when the pilot pressure is detected by the pressure switch, to thereby prevent wrong operation in switching.

Abstract: An oil hydraulic circuit for a hydraulic shovel with which a composite operation can be performed readily and smoothly without special skill in operation of the hydraulic shovel. The oil hydraulic circuit comprises a first actuator which can operate with pressure oil from a predetermined one or both of a pair of hydraulic directional control valve sets, a second actuator which operates only with pressure oil from the other hydraulic directional control valve set, a proportional changing over device interposed intermediately in a pipe line communicating the other hydraulic directional control valve set with a first actuator for adjusting the maximum meter-in opening value to the first actuator in response to a magnitude of a signal received at a signal receiving portion of the proportional changing over device, and a controller for arbitrarily adjusting the signal to be supplied to the signal receiving portion of the proportional changing over device.