Patent ID: 9713881
Date: 2017-07-25
CPC Classifications: B27B

Claim:
1. A portable handheld chain saw comprising: a housing; a guide bar defining a longitudinal axis and being mounted on said housing and having a periphery; a saw chain mounted on said guide bar so as to be movable about said guide bar on said periphery thereof; a fastening arrangement mounted on said housing adjacent said guide bar; said fastening arrangement being transferable between a released state wherein said guide bar is shiftable in the direction of said longitudinal axis thereof and a tightened state wherein said guide bar is clamped against said housing; said fastening arrangement including a threaded member defining a rotational axis and extending laterally from said housing and an actuating device threadably engaging said threaded member so as to be rotatable about said rotational axis in a tightening direction to clamp said guide bar against said housing and to bring said fastening arrangement into said tightened state and rotatable about said rotational axis in a releasing direction to loosen said guide bar and to transfer said fastening arrangement into said released state; said fastening arrangement further including a tensioning device coupling said actuating device to said guide bar for tensioning said saw chain by moving said guide bar in the direction of said longitudinal axis thereof; said tensioning device further including a coupling mechanism to translate a rotary motion of said actuating device into a linear movement of said guide bar; said coupling mechanism including a displacement element mounted on said guide bar and a rotary element coupled to said displacement element for imparting a linear movement to said guide bar via said displacement element in response to a rotational movement of said rotary element about said rotational axis; said tensioning device further including a spiral spring having a first end connected to said actuating device and a second end; and, an entraining mechanism connected between said second end of said spiral spring and said rotary element for entraining the rotational movement of said actuating device and transmitting the same to said rotary element; and, said spiral spring being configured to be tensioned in response to a manual rotation of said actuating device to impart a torque via said entraining mechanism to said rotary element so as to, in turn, impart said linear movement to said guide bar while said fastening arrangement is still in said released state.