Chain saw device

In a chain saw including a frame and having a driving motor,

• a saw chain cassette comprising a saw bar having a saw chain entrained therearound and a sprocket for engaging said chain and adapted to be driven by said motor,
• and a movable clamping cover adapted for interengagement with said frame while receiving said cassette between said cover and said frame in position for said sprocket to be driven by said motor, wherein said clamping cover removably secures said cassette against said frame by releasable compression to provide for rapid insertion and removal of said cassette, wherein said cover is hingedly attached to said frame and is provided with an over-center locking mechanism for releasably holding said cover against said frame with said cassette in place.

In a chain saw including a frame and having a driving motor,

• a saw chain cassette removably mountable on said frame as a unit, said cassette comprising a saw bar having a saw chain entrained therearound and a sprocket for engaging said chain and adapted to be driven by said motor, said sprocket being relatively movable along said cassette,
• and biasing means located on said cassette for yieldably urging said sprocket in a rearward direction along said cassette for maintaining said chain in tensioned relation as entrained around said saw bar when said cassette is removed from said frame.

A saw chain cassette for use with a chain saw having a driving motor, said cassette comprising a saw bar having a saw chain entrained therearound and a sprocket for engaging said chain and adapted to be driven by said motor, said sprocket being relatively movable along said cassette, and biasing means located on said cassette for yieldably urging said sprocket in a rearward direction along said cassette for maintaining said chain in tensioned relation as entrained around said saw bar when said cassette is removed from said frame.