Claims
- 1. In a manually portable chain saw having housing means; manual gripping handle means mounted on said housing means; engine means carried by said housing means; a cutting chain; support bar means projecting forwardly from said housing means for supporting said cutting chain for endless movement; rotation transmitting means operably connected to said engine for driving said cutting chain; and safety braking means for stopping said cutting chain, said safety braking means comprising:
- sensing arm means mounted on said housing means for swinging movement;
- said sensing arm means being located adjacent said gripping handle means and arranged to be swung in response to being engaged by an arm or hand of an operator;
- said sensing arm means including a projection extending therefrom;
- a flexible brake band including a first end anchored to said housing means and a second end coupled to said sensing arm means for movement therewith such that as said arm means is swung, it shifts said brake band into frictional braking relationship with said rotation transmitting means to stop said cutting chain; and
- multi-stage brake control means including:
- spring means constantly biasing said sensing arm means toward swinging movement to brake said rotation transmitting means, and
- a latch for releasably retaining said sensing arm means, said
- latch comprising a strip having first and second ends;
- said first end being fixedly secured to said housing;
- said second end being configured to flexibly receive said projection so as to normally resist forward movement of said sensing arm means, and to be flexed in response to engagement of said sensing arm means by an arm or hand of an operator, to release said sensing arm means and allow said spring means to bias said brake band into braking relationship with said rotation transmission means.
- 2. A manually portable chain saw according to claim 1 wherein said second end of said strip includes a reset lip extending forwardly of said notch.
- 3. A manually portable chain saw according to claim 1 wherein said second end of said brake band is connected to a second projection on said sensing arm means, said second projection being fastened to a crank arm lever of said sensing arm.
- 4. A manually portable chain saw according to claim 3 wherein said second projection comprises a pin extending from both sides of said crank arm lever, said second end of said brake band being bifurcated and mounted on said pin at both sides of said crank arm lever.
- 5. A manually portable chain saw according to claim 1 wherein said coil spring comprises a compression spring.
- 6. A manually portable chain saw according to claim 5 including a rod connected to said sensing arm and passing through a guide opening in said housing means; said coil compression spring being disposed around said rod and being compressably disposed between said first projection of said sensing arm and an abutment shoulder on said housing means.
- 7. In a manually portable chain saw having housing means; manual gripping handle means mounted on said housing means; engine means carried by said housing means; a cutting chain; support bar means projecting forwardly from said housing means for supporting said cutting chain for endless movement; rotation transmitting means operably connected to said engine for driving said cutting chain; and safety braking means for stopping said cutting chain, said safety braking means comprising:
- a sensing arm mounted on said housing means for swinging movement, said sensing arm being located adjacent said gripping handle means and arranged to be swung forwardly from a rest position to a braking position in response to being engaged by an arm or hand of an operator, said sensing arm having:
- a first projection extending therefrom, said first projection including a curved forward portion,
- a crank arm lever rotatable with said sensing arm, and
- a second projection on said crank arm lever;
- a flexible brake band including a first end anchored to said housing means and a second end coupled to said second projection for movement therewith such that as said arm means is swung forwardly, it shifts said brake band into frictional braking relationship with said rotation transmitting means to stop said cutting chain; and
- brake control means comprising:
- a coil spring constantly biasing said sensing arm toward forward swinging movement to brake said rotation transmitting means, and
- a latch for releasably retaining said sensing arm means, said latch comprising a strip having first and second ends;
- said first end being fixedly secured to said housing;
- said second end having a bent configuration defining a notch for receiving said curved portion of said first projection to resist forward movement of said sensing arm means;
- said strip extending forwardly from said housing in overlying position above said spring means and said first projection such that said strip is flexed upwardly in response to engagement of said sensing arm means by an arm or hand of an operator, to release said sensing arm means and allow said spring means to bias said brake band into braking relationship with said rotation transmission means.
- 8. A manually portable chain saw according to claim 7 wherein said second end of said strip includes a reset lip extending forwardly of said notch.
- 9. A manually portable chain saw according to claim 7 wherein said second projection comprises a pin extending from both sides of said crank arm lever, said second end of said brake band being bifurcated and mounted on said pin at both sides of said crank arm lever.
Parent Case Info
This is a continuation, of application Ser. No. 515,045, filed Oct. 15, 1974, now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
3292742 |
Thomas |
Dec 1966 |
|
3776331 |
Gustafsson |
Dec 1973 |
|
3937306 |
Naslund et al. |
Feb 1976 |
|
Continuations (1)
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Number |
Date |
Country |
Parent |
515045 |
Oct 1974 |
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