Construction machine

1. A construction machine comprising:

an automotive lower traveling structure ( 2 );

an upper revolving structure ( 3 ) rotatably mounted on said lower traveling structure ( 2 ) and having a cab ( 8 ) provided on a revolving frame ( 5 ) forming a support structural body; and

a working mechanism ( 4 ) provided on the front side in the front-rear direction of said upper revolving structure ( 3 ), capable of moving upward/downward;

said cab ( 8 ) being provided with a cab box ( 13 ) in which five pillars ( 14 to 18 ) are provided extending in the vertical direction by being located on left front, right front, left intermediate, left rear, and right rear and a space between each of said pillars ( 14 to 18 ) is covered by a front surface ( 13 A), a left front side surface ( 13 B), a left rear side surface ( 13 C), a right side surface ( 13 D), a rear surface ( 13 E), and a top surface ( 13 F) and the inside becomes an operator's room ( 13 G); and

a door ( 24 ) having the rear end side mounted on said left intermediate pillar ( 16 ) rotatably in the front-rear direction in order to open/close an entrance way ( 21 ) between said left front pillar ( 14 ) and said left intermediate pillar ( 16 ) of said cab box ( 13 ), characterized in that:

said left front pillar ( 14 ) is formed of a pillar-side stepped surface portion ( 14 B) in which an intermediate portion in the front-rear direction of a left side surface portion ( 14 A) is bent to said operator's room ( 13 G) side, a pillar-side opposite surface portion ( 14 C) provided extending to the rear side from a depth portion of said pillar-side stepped surface portion ( 14 B) and opposed to said door ( 24 ) in a closed state, and a rear surface portion ( 14 D) extending from a rear end portion of said pillar-side opposite surface portion ( 14 C) to said operator's room ( 13 G) side;

an engaging member ( 23 ) composed of a mounting plate ( 23 A) having a protruding portion ( 23 A 1 ) protruding to said door ( 24 ) side from said pillar-side opposite surface portion ( 14 C) and an engaging ring ( 23 B) protruding rearward from said mounting plate ( 23 A) is provided on said rear surface portion ( 14 D) of said left front pillar ( 14 );

said door ( 24 ) has an outer surface plate ( 24 A) forming an outer side surface of said door ( 24 ), an inner surface plate ( 24 B) opposite to said outer surface plate ( 24 A) and forming an inner side surface of said door ( 24 ), a door-side opposite surface plate ( 24 C) arranged inside said outer surface plate ( 24 A) by being located on the front side of said inner surface plate ( 24 B) and opposed to said pillar-side opposite surface portion ( 14 C) when said door ( 24 ) is closed, a door-side stepped surface plate ( 24 D) forming a step between said inner surface plate ( 24 B) and said door-side opposite surface plate ( 24 C), and a mounting opening ( 24 E) provided on said door-side stepped surface plate ( 24 D) at a position corresponding to said engaging member ( 23 );

a door holding member ( 28 ) opposite to said engaging ring ( 23 B) of said engaging member ( 23 ) and holding said door ( 24 ) at a closed position by being engaged with said engaging ring ( 23 B) when said door ( 24 ) is closed is provided on said mounting opening ( 24 E) of said door ( 24 );

a retreating recessed portion ( 29 ) located on the front side of said door holding member ( 28 ) and recessed toward said outer surface plate ( 24 A) is provided on said door-side opposite surface plate ( 24 C) of said door ( 24 ); and

when said door ( 24 ) is brought to the closed position, interference with said protruding portion ( 23 A 1 ) of said mounting plate ( 23 A) of said engaging member ( 23 ) is avoided by said retreating recessed portion ( 29 ).

2. The construction machine according to claim 1 , wherein

a seal member ( 27 ) for sealing a space between said cab box ( 13 ) and said door ( 24 ) is provided on either one side of said pillar-side opposite surface portion ( 14 C) of said left front pillar ( 14 ) and said door-side opposite surface plate ( 24 C) of said door ( 24 ); and

said retreating recessed portion ( 29 ) is arranged between said door holding member ( 28 ) and said seal member ( 27 ).

3. The construction machine according to claim 2 , wherein

a depth dimension (L 3 ) of said retreating recessed portion ( 29 ) is set to a value larger than a difference between a protruding dimension (L 1 ) of said protruding portion ( 23 A 1 ) provided on said mounting plate ( 23 A) of said engaging member ( 23 ) and a width dimension (L 2 ) when said seal member ( 27 ) is deformed by closing said door ( 24 ).

4. The construction machine according to claim 1 , wherein

said door holding member ( 28 ) has a case ( 28 A) mounted on said mounting opening ( 24 E) of said door ( 24 ) and an engaging pawl ( 28 C) provided rotatably on said case ( 28 A) and engaged with said engaging ring ( 23 B) of said engaging member ( 23 ) when said door ( 24 ) is closed.

5. The construction machine according to claim 4 , wherein

on said outer surface plate ( 24 A) of said door ( 24 ), an outer side door knob ( 25 ) for operating said engaging pawl ( 28 C) from the outside is provided; and

on said inner surface plate ( 24 B) of said door ( 24 ), an inner side door knob ( 26 ) for operating said engaging pawl ( 28 C) from said operator's room ( 13 G) is provided.