초록 ▼

A chain saw is provided with a saw chain cassette and a releasable clamping cover for holding the cassette against the side of the chain saw frame. The clamping cover, together with the cassette and the chain saw frame, have aligning surfaces extending in a direction longitudinal of the cassette saw

A chain saw is provided with a saw chain cassette and a releasable clamping cover for holding the cassette against the side of the chain saw frame. The clamping cover, together with the cassette and the chain saw frame, have aligning surfaces extending in a direction longitudinal of the cassette saw bar for preventing relative rotation between the saw bar and the frame. A tightening mechanism for the cassette is used for urging the saw bar forwardly with respect to its drive sprocket and a further mechanism is provided within the cassette comprising a spring biased shoe for urging the cassette sprocket in a direction for tightening the chain when the cassette is removed from the chain saw frame. A camming device on the frame engages the shoe when the cassette is installed on the frame for holding the shoe away from the sprocket such that the latter can be driven by the chain saw motor drive shaft.

대표청구항 ▼

1. 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 fra

1. 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, said cover and said frame having pads for engaging sides of said cassette, said cassette having longitudinal alignment ribs with which said pads are matingly cooperable for holding said cassette against rotation. 2. The apparatus according to claim 1 wherein said motor and said sprocket are provided with a splined interconnection positioned for mating relation as said cassette is mounted on said frame. 3. The apparatus according to claim 1 wherein said cassette includes a sprocket entrapping portion for receiving said sprocket, said ribs being located forward and rearward of said sprocket on said sprocket entrapping portion, said pads being matingly receivable between said ribs both forward and rearward of said sprocket on said sprocket entrapping portion. 4. The apparatus according to claim 1 wherein said frame is further provided with ridges on either side of said pads cooperating with said pads to form grooves receiving said ribs on said cassette. 5. The apparatus according to claim 1 wherein said cover is hingedly attached to said frame and is provided with releasable locking means for holding said cover against said frame with said cassette in place. 6. The apparatus according to claim 1 wherein said cover is hingedly attached to said frame and is provided with an aperture, while said frame is provided with a threaded connection for passing through said aperture and releasably holding said cover against said frame with said cassette in place. 7. The apparatus according to claim 1 wherein said sprocket is relatively movable along said cassette, and said frame rearward of said cassette is provided with means for adjustably bearing on said cassette rearward of said sprocket and urging said saw bar forwardly relative to said chain as engaged by said sprocket. 8. The apparatus according to claim 7 further including a chain tightening mechanism for said cassette adapted to maintain said chain in tensioned relation entrained around said saw bar when said cassette is removed from said frame, said chain tightening mechanism comprising biasing means located on said cassette for yieldably urging said sprocket in a rearward direction along said cassette for tightening said chain, and a cam member mounted on said frame for disengaging said chain tightening mechanism when said cassette is mounted on said frame. 9. The apparatus according to claim 1 wherein said sprocket is relatively movable along said cassette, and further including a chain tightening mechanism for said cassette adapted to maintain said chain in tensioned relation entrained around said saw bar when said cassette is removed from said frame, said chain tightening mechanism comprising means located on said cassette for yieldably urging said sprocket in a rearward direction along said cassette for tightening said chain. 10. The apparatus according to claim 9 further including a cam member mounted on said frame for disengaging said chain tightening mechanism when said cassette is mounted on said frame. 11. The apparatus according to claim 10 wherein said biasing means includes a shoe slidably mounted on said cassette for engaging the periphery of said sprocket on the forward side thereof and a spring for urging said shoe rearwardly against said sprocket, and said cam member comprising a dog fixedly mounted on said frame, said dog and said shoe having cammed interengaging surfaces by means of which said shoe is moved forwardly away from said sprocket when said cassette is mounted on said frame. 12. The apparatus according to claim 1 further including an adjustable sharpening mechanism attached to said frame for bearing on said chain adjacent said sprocket with said cassette in position on said frame, a portion of the inside wall of said cassette facing said frame being indented to expose said chain in the area of said sharpening mechanism. 13. 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. 14. The apparatus according to claim 13 wherein said cassette has aligning surfaces which are engaged as said cassette is secured against said frame for accurately positioning and holding said cassette. 15. The apparatus according to claim 13 wherein said sprocket is relatively movable along said cassette, and further including a chain tightening mechanism for said cassette adapted to maintain said chain in tensioned relation entrained around said saw bar when said cassette is removed from said frame, said chain tightening mechanism including biasing means located on said cassette for yieldably urging said sprocket in a rearward direction along said cassette for tightening said chain, and a cam member mounted on said frame for disengaging said chain tightening mechanism when said cassette is mounted on said frame. 16. The apparatus according to claim 15 wherein said frame rearward of said cassette is provided with means for adjustably bearing on said cassette rearward of said sprocket and urging said saw bar forwardly relative to said chain as engaged by said sprocket. 17. 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. 18. The apparatus according to claim 17 further including a cam member mounted on said chain saw for disengaging said biasing means when said cassette is mounted on said frame. 19. The apparatus according to claim 17 wherein said frame rearward of said cassette is provided with means for adjustably bearing on said cassette rearward of said sprocket and urging said saw bar forwardly relative to said chain as engaged by said sprocket. 20. The apparatus according to claim 19 wherein said cassette is provided with aligning surfaces engaged as said cassette is mounted on said frame for accurately positioning and holding said cassette, said aligning surfaces extending in a direction generally longitudinal of said cassette to facilitate longitudinal adjustment of said cassette relative to said chain. 21. The apparatus according to claim 20 wherein said cassette includes a sprocket entrapping portion for receiving said sprocket, said aligning surfaces including ribs on said cassette forward and rearward of said sprocket entrapping portion, said apparatus being provided with a clamping cover adapted for interengagement with said frame while removably receiving said cassette between said cover and said frame in position for said sprocket to be driven by said motor, said cover and said frame having pads matingly receivable between said ribs for holding said cassette. 22. 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.