Work machine

Abstract

An attachment base (15) to which a counterweight (13) is attached is provided at a rear portion of an upper turning body (4), a boss hole (15a) is provided to penetrate through the attachment base (15), and a boss recessed portion (13a) is formed in a front surface of the counterweight (13). A boss member (18) is inserted into the boss recessed portion (13a) of the counterweight (13) via the boss hole (15a) in the attachment base from a front side, and a bolt (21) is caused to be screwed into the boss member (18) through the counterweight (13) from a rear side. An abutment surface (18c) of the boss member (18) is caused to abut a front surface of the attachment base (15) with a fastening force of the bolt (21) to thereby fasten the counterweight (13) to the attachment base (15) and cause the attachment base (15) to support a weight of the counterweight (13) via the boss member (18).

1 . A work machine capable of detachably attaching a counterweight to an attachment base provided at a rear portion of a vehicle body, the work machine comprising:
 a boss hole that is provided to penetrate through the attachment base;   a boss recessed portion that is formed in a front surface of the counterweight;   a boss member that is inserted into the boss recessed portion in the counterweight from a front side via the boss hole in the attachment base, is fastened to the counterweight with a first fastening member, and has a lower surface abutting a lower wall inside the boss hole and an upper surface abutting an upper wall inside the boss recessed portion; and   a second fastening member that fastens the counterweight to the attachment base.   
     
     
         2 . The work machine according to  claim 1 ,
 wherein the first fastening member is screwed into the boss member via a bolt hole in the counterweight from a rear side, and draws the boss member into the boss recessed portion, and fastens the boss member, and   a flange portion abutting the attachment base from the front side is integrally formed with the boss member, and the attachment base is sandwiched between an abutment surface of the flange portion and the front surface of the counterweight by a fastening force of the fastening member.   
     
     
         3 . The work machine according to  claim 1 , further comprising:
 a pedestal that has a guide surface facing upward in parallel with an axis of the boss hole and provided on a front side of the attachment base,   wherein the boss member is disposed on the guide surface and is movable in a front-rear direction by being guided by the guide surface.   
     
     
         4 . The work machine according to  claim 1 , wherein the second fastening member is inserted into a bolt hole in the counterweight from a rear side, and fastens the attachment base to the counterweight. 
     
     
         5 . The work machine according to  claim 1 ,
 wherein the boss member has a square shape, and   at least one of the boss hole in the attachment base and the boss recessed portion in the counterweight has a square shape corresponding to a sectional shape of the boss member and has restricted relative rotation.   
     
     
         6 . The work machine according to  claim 3 , wherein the boss member is fixed on the guide surface of the pedestal with a detachable fixation metal fitting. 
     
     
         7 . The work machine according to  claim 1 , wherein the boss recessed portion forms a clearance in an up-down direction with respect to the boss member. 
     
     
         8 . The work machine according to  claim 1 , wherein the boss hole in the attachment base, the boss recessed portion in the counterweight, and the boss member are each provided in pairs at intervals in a left-right direction.