Chain tension device in a chain saw
AssigneeMakita Corporation
InventorsMakoto Mizutani, Hideki Abe
Life of this patent
Estimating the term…
Abstract
A chain tension device for tensioning a cutting chain of a chain saw utilizing a guide bar having an outer periphery and a drive sprocket. The chain saw body supports the guide bar, the sprocket and a drive source. A cutting chain is wound around the sprocket and the outer periphery of the guide bar and a leaf spring is supported by the chain saw body and interposed between the guide bar and the sprocket. The leaf spring abuts and biases the guide bar away from the sprocket so as to apply automatically an appropriate amount of tension to the cutting chain.
Claims16
A chain saw, having a chain tension device for tensioning a cutting chain comprising:
- a guide bar having an outer periphery for guiding a cutting chain therearound;
- a sprocket for driving the cutting chain, and said sprocket being driven by a drive mechanism;
- the cutting chain wrapped around said sprocket and said outer periphery of said guide bar for rotation therearound;
- a chain saw body supporting said guide bar, said sprocket and said drive mechanism and including a leaf spring insertion hole formed in the chain saw body and situated between said guide bar and said sprocket;
- and
- a leaf spring interposed between an end of said guide bar adjacent said sprocket and said sprocket, said leaf spring, being captively supported and housed within the leaf spring insertion hole, resiliently and directly engaging said chain saw body and said guide bar end to bias said guide bar in a longitudinal direction of said guide bar, away from said sprocket, thereby applying a desired tension to said cutting chain.
A chain saw having a chain tension device for tensioning a cutting chain, comprising:
- a guide bar having a longitudinal axis and an outer periphery for guiding a cutting chain therearound;
- a sprocket for driving a cutting, and said sprocket being driven by a drive mechanism;
- a chain saw body supporting said guide bar, said sprocket and said drive mechanism;
- a cutting chain wrapped around said sprocket and said outer periphery of said guide bar for rotation therearound;
- a leaf spring interposed between an end of said guide bar adjacent said sprocket and said sprocket, a first portion of said leaf spring directly abutting and biasing said end of the guide bar in a longitudinal direction along the longitudinal axis, of said guide bar, away from said sprocket thereby applying a desired tension to said cutting chain;
- and
- a second portion of said leaf spring being captively supported and housed within a leaf spring insertion hole defined by and located in said chain saw body, said leaf spring partially extending from said leaf spring insertion hole transversely of said guide bar longitudinal axis and engaging said adjacent end of the guide bar for applying a desired cutting chain tension.
A chain saw having a chain tension device for tensioning a cutting chain, the chain saw comprising:
- an adjustable guide bar having an outer periphery for guiding a cutting chain therearound;
- a sprocket for driving the cutting chain about the outer periphery of the guide bar, and said sprocket being driven by a drive mechanism;
- the cutting chain wrapped around said sprocket and said outer periphery of said guide bar for rotation therearound;
- a chain saw body supporting said guide bar, said sprocket and said drive mechanism and including a leaf spring insertion hole formed in the chain saw body, the leaf spring insertion hole extending substantially perpendicular to a plane defined by said guide bar;
- and
- a second arm portion of the leaf spring interposed between an end of said guide bar, located adjacent said sprocket, and a first arm portion of said leaf spring being captively supported and at least partially housed within the leaf spring insertion hole, the second arm portion resiliently and directly engaging with the end of said guide bar, located adjacent said sprocket, to bias said guide bar longitudinal away from said sprocket thereby applying a desired tension to said cutting chain.
Dependencies are inferred from the claim text.