Cutting devices

A cutting device comprising:

• a cutting unit having a rotational shaft;
• a fixing device configured to fixedly attach a circular cutter to the rotational shaft;
• and
• an operation device coupled to the fixing device;
• wherein the operation device comprises:
• an operation member configured to apply an operational force to the fixing device for fixation of the circular cutter to the rotational shaft and for releasing fixation of the circular cutter to the rotational shaft;
• and
• a friction reducing device arranged in an operational force transmission path between the operation member and the fixing device and configured to reduce a frictional force produced between the operation member and the fixing device when the operation member applies the operational force to the fixing device, wherein:
• the operation member comprises an operation shaft and an operation knob,
• the operation shaft is coupled to the rotational shaft, so that the operation shaft is coaxially rotatable relative to the rotational shaft and movable relative to the rotational shaft in an axial direction of the rotational shaft,
• the operation knob has an outer portion defining an outer peripheral surface and an inner portion including an engaging portion engaging the operation shaft in the rotational direction,
• the outer portion and the inner portion are connected to each other and extend coaxial with each other in the axial direction,
• the friction reducing device comprises a bearing coaxially fitted on the operation shaft,
• an engaging device is disposed between an outer peripheral surface of the operation shaft and an inner peripheral surface of the inner portion of the operation knob and is configured to inhibit movement of the inner portion of the operation knob away from the rotational shaft in a first direction along the axial direction,
• the bearing contacts a part of an outer peripheral portion of the operation shaft in the axial direction,
• the inner portion of the operation knob has an end portion in a second direction, which is along the axial direction and opposite to the first direction,
• the end portion of the inner portion of the operation knob is directly opposed to the bearing in the axial direction,
• the operation device further comprises a pressing member that is coaxially rotatable fitted on the operation shaft, and
• the bearing is axially interposed between the operation knob and the pressing member.

A cutting device comprising:

• a cutting unit having a rotational shaft;
• a fixing device configured to fixedly attach a circular cutter to the rotational shaft;
• and
• an operation device coupled to the fixing device;
• wherein the operation device comprises:
• an operation member configured to apply an operational force to the fixing device for fixation of the circular cutter to the rotational shaft and for releasing fixation of the circular cutter to the rotational shaft;
• and
• a friction reducing device arranged in an operational force transmission path between the operation member and the fixing device and configured to reduce a frictional force produced between the operation member and the fixing device when the operation member applies the operational force to the fixing device, wherein:
• the operation member comprises an operation shaft and an operation knob,
• the operation shaft is coupled to the rotational shaft, so that the operation shaft is coaxially rotatable relative to the rotational shaft and movable relative to the rotational shaft in an axial direction of the rotational shaft,
• the operation knob has an outer portion defining an outer peripheral surface and an inner portion including an engaging portion engaging the operation shaft in the rotational direction,
• the outer portion and the inner portion are connected to each other and extend coaxial with each other in the axial direction,
• the friction reducing device comprises a bearing coaxially fitted on the operation shaft,
• an engaging device is disposed between an outer peripheral surface of the operation shaft and an inner peripheral surface of the inner portion of the operation knob and is configured to inhibit movement of the inner portion of the operation knob away from the rotational shaft in a first direction along the axial direction,
• the bearing contacts a part of an outer peripheral portion of the operation shaft in the axial direction,
• the inner portion of the operation knob has an end portion in a second direction, which is along the axial direction and opposite to the first direction, and
• the end portion of the inner portion of the operation knob is directly opposed to and abutting the bearing in the axial direction.