Chain saw

A chain saw, comprising:

• a housing;
• a cutting chain;
• a chain wheel driven by a motor, supported in the housing, and moving the cutting chain;
• a guide plate for supporting and guiding the cutting chain wherein one end of the guide plate is supported on the housing with the other end thereof extends out of the housing in a longitudinal direction of the housing;
• a cover plate cooperating with the housing to hold the guide plate to prevent the guide from shaking in a vertical direction;
• and
• a chain wheel tensioning mechanism comprising a tensioning nut, a transmission member and, a tensioning handwheel, wherein the transmission member comprises an input shaft mounted on the housing and rotatable relative to the housing, a first transmission element driven by the input shaft, a second transmission element engaging the first transmission element, and an output shaft driven by the second transmission element, wherein the tensioning handwheel is coupled to the input shaft of the transmission member, wherein the tensioning handwheel at least partially extends out of the housing, wherein the tensioning nut is fixedly connected with the guide plate and threadedly connected with the output shaft of the transmission member to enable the guide plate to move relative to the output shaft, wherein the input shaft is disposed in a plane parallel to the guide plate, and wherein an angle between the input shaft and the output shaft of the transmission member is greater than 0° and less than 180°.