Joint mechanism for construction machine

Abstract

A joint mechanism for a construction machine includes: a first member having a first facing surface; a second member rotatable around a rotation axis relative to the first member and having a second facing surface facing the first facing surface; a power transmission mechanism for transmitting power for rotation to the second member; a first wall protruding from the first facing surface and having an annular shape around the rotation axis; and a second wall protruding from the second facing surface and having an arc-like shape around the rotation axis. The power transmission mechanism is located on an inner side of the first wall in a radial direction around the rotation axis, and the second wall is located on an outer side of the first wall in the radial direction and overlaps at least partly with the first wall in a direction along the rotation axis.

What is claimed is: 
     
         1 . A joint mechanism for a construction machine, comprising:
 a first member having a first facing surface;   a second member rotatable around a rotation axis relative to the first member and having a second facing surface facing the first facing surface;   a power transmission mechanism for transmitting power for rotation to the second member;   a first wall protruding from the first facing surface and having an annular shape around the rotation axis; and   a second wall protruding from the second facing surface and having an arc-like shape around the rotation axis,   wherein the power transmission mechanism is located on an inner side of the first wall in a radial direction around the rotation axis, and   wherein the second wall is located on an outer side of the first wall in the radial direction and overlaps at least partly with the first wall in a direction along the rotation axis.   
     
     
         2 . The joint mechanism for a construction machine according to  claim 1 , further comprising a third wall protruding from the second facing surface and having an annular shape around the rotation axis,
 wherein the third wall is located between the power transmission mechanism and the first wall in the radial direction and overlaps at least partly with the first wall in the direction along the rotation axis.   
     
     
         3 . The joint mechanism for a construction machine according to  claim 1 , wherein the second wall extends around the rotation axis for 180 degrees or more. 
     
     
         4 . The joint mechanism for a construction machine according to  claim 1 ,
 wherein the second member includes a bucket with an opening,   wherein an opening direction refers to a direction perpendicular to an opening surface of the bucket and extending from an interior to an exterior of the bucket through the opening surface,   wherein, as viewed in a direction along the rotation axis, a first straight line refers to a virtual straight line connecting the rotation axis and the opening surface by a shortest distance, and a second straight line refers to a virtual straight line extending from the rotation axis in the opening direction, and   wherein in a circumferential direction around the rotation axis, the second wall extends over an entire angular region formed by the first straight line and the second straight line on a side toward which the opening surface is open.   
     
     
         5 . The joint mechanism for a construction machine according to  claim 1 , further comprising:
 a first stopper protruding from the first member; and   a second stopper protruding from the second member and configured to contact the first stopper when the second member has rotated by a first angle in a first rotational direction from a predetermined reference position.   
     
     
         6 . The joint mechanism for a construction machine according to  claim 5 , further comprising a third stopper protruding from the second member and configured to contact the first stopper when the second member has rotated by the first angle from the reference position in a second rotational direction opposite to the first rotational direction. 
     
     
         7 . The joint mechanism for a construction machine according to  claim 5 , further comprising:
 a power source configured to provide power to the power transmission mechanism; and   a controller configured to control the power source,   wherein the controller is capable of:
 receiving a switching signal from an outside of the controller; and 
 switching, based on the switching signal, between a first mode, in which power output by the power source is limited to less than a specified value, and a second mode, in which power output by the power source is permitted to be equal to or larger than the specified value. 
   
     
     
         8 . A joint mechanism for a construction machine, comprising:
 a first member;   a second member rotatable relative to the first member;   a first stopper protruding from the first member; and   a second stopper protruding from the second member and configured to contact the first stopper when the second member has rotated by a first angle from a predetermined reference position.   
     
     
         9 . The joint mechanism for a construction machine according to  claim 8 , further comprising a power transmission mechanism connecting the first member and the second member so as to be capable of relative rotation and configured to transmit power for rotation to the second member,
 wherein the second member includes a bucket with an opening.   
     
     
         10 . The joint mechanism for a construction machine according to  claim 8 ,
 wherein the second member includes a bucket with an opening,   wherein an opening direction refers to a direction perpendicular to an opening surface of the bucket and extending from an interior to an exterior of the bucket through the opening surface, and   wherein, as viewed in a direction along a rotation axis of the second member, when the second stopper is at a position at which the second stopper contacts the first stopper, a virtual half line extending from the rotation axis in a direction opposite to the first stopper intersects a virtual half line extending from the opening surface in the opening direction.