Shoulder harness for portable work machine

1. A shoulder harness for a portable work machine comprising:

a back member that is to be located on a back of an operator, said back member including a main frame, to which a downward extension frame connected with a waist belt is detachably attached;

right and left shoulder belts that respectively extend from right and left upper end portions of said back member;

a joint buckle that is to be located on a chest of said operator, distal ends of said right and left shoulder belts being connected to said joint buckle;

a hip pad that is to be located on a side of a waist of said operator, and is provided with a locking device, to which a work machine is connected;

a relay member that is located above said locking device, and is connected to said locking device by a hanging member which is composed of a band-like belt;

a rear suspension belt that is connected to said relay member and said back member;

a front suspension belt that is connected to said relay member and said joint buckle;

a mechanism for attaching and detaching said downward extension frame to and from said main frame, including a first shape portion formed in said main frame, and a second shape portion formed in said downward extension frame, wherein said downward extension frame is attachable to and detachable from said main frame by engagement and disengagement between said first and second shape portions; and

an armpit belt that extends along an armpit on one side of said operator from said back member, wherein a distal end of said armpit belt is connected to said joint buckle.

2. The shoulder harness for a portable work machine of claim 1 , wherein said first shape portion of said main frame and said second shape portion of said downward extension frame are engageable or disengageable without using a tool.

3. The shoulder harness for a portable work machine of claim 2 , wherein said main frame and said downward extension frame are plastic moldings,

said first shape portion is integrally formed in said main frame, and

said second shape portion is integrally formed in said downward extension frame.

4. The shoulder harness for a portable work machine of claim 1 , wherein said back member includes said downward extension frame, to which said waist belt is connected, and

said relay member is connected to said waist belt.

5. The shoulder harness for a portable work machine of claim 1 , further comprising an auxiliary belt that is connected to a distal end portion of said armpit belt and a distal end portion of said right or left shoulder belt on the side where said armpit belt is located.

6. The shoulder harness for a portable work machine of claim 1 , further comprising a back pad assembly that is attachable to and detachable from said main frame,

wherein said back pad assembly includes a back pad cushion,

said back pad cushion includes a back pad body that is to be located on a back of said operator, and

said right and left shoulder belts respectively extend from right and left upper ends of said back pad body.

7. The shoulder harness for a portable work machine of claim 1 , wherein said front suspension belt and said rear suspension belt are composed of a single continuous belt, and

a front end portion of said single belt is detachably connected to said joint buckle, and a rear end portion of said single belt is detachably connected to said main frame.

8. The shoulder harness for a portable work machine of claim 1 , wherein one shoulder belt located opposite to said locking device, out of said right and left shoulder belts, is formed in a curved shape, and

said curved shoulder belt has a curved shape gradually displaced to an inner side while extending to a front of said operator along a shoulder from said back of said operator.

9. The shoulder harness for a portable work machine of claim 1 , wherein said relay member is composed of a plate member,

an upper end portion of said relay member has a shape inclined in a direction opposite to the operator to separate from said operator, and

said hanging member is connected to said inclined upper end portion.

10. The shoulder harness for a portable work machine of claim 1 , wherein a length of said handing member is adjustable.