Patent US3793727A successfully refreshed from Google Patents.
US3793727A
Expired / Lapsed
US
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Chain saw safety method and apparatus
Assignee: Mcculloch Corp
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Filing: 1972-10-04
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Granted: 1974-02-26
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Expires: 1992-10-04
Abstract
Abstract A method and apparatus for preventing injury to an operator of a chain saw of the type having a frame, a frame handle, a control handle, a guide bar, a cutting chain and power means mounted on the frame and operably connected to the cutting chain for driving the cutting chain on the guide bar. The apparatus includes a first lever pivotally mounted adjacent to the frame handle and a second lever pivotally mounted adjacent to the control handle. A self-locking brake is biased toward actuation and upon actuation is operably sufficient to instantly stop movement of the cutting chain and stall out the chain saw power means. Actuation of the self-locking brake is controlled by engaging the first and second levers against the frame and control handles respectively. This engagement is translated through a linkage system to overcome the aforementioned bias and disengage the self-locking brake. Upon release of either the first or second levers, or both, from engagement with the frame or control handles respectively the brake will be immediately actuated. The method includes the steps of controlling the actuation of a self-locking brake and actuating the brake in the event an operator''s hand slips from either the frame handle or the control handle. If such an event occurs the method includes braking the cutting chain to an immediate stop and thus minimizing the possibility of injury to the operator.
Inventors
- 👤 H Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:21
CPC Classifications
B; B27; B27B; B27B17/00; B27B17/08; B27B17/083; Y; Y10; Y10S; Y10S83/00; Y10S83/01
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
193 words
A chain saw adapted to be held by an operator using both hands comprising: a frame having, a frame handle, and a control handle; a guide rail connected to said frame; a cutting chain operably carriEd by said guide rail; power means mounted on said frame and operably connected to said cutting chain for driving said cutting chain on said guide rail; brake means operably connected to said cutting chain for stopping movement of said cutting chain on said guide rail; and brake actuation means connected to said brake means for controlling the application of said brake means including, a first lever pivotally mounted adjacent to said frame handle, a second lever pivotally mounted adjacent to said control handle, a first link connected at one end to said first lever, a second link connected at one end to said second lever, linkage means connected at one end to the other ends of said first and second links and connected at the other end to said brake means for maintaining said brake means in an actuated posture unless the first and second levers are held against the frame handle and the control handle, respectively.
Claim 2
Dependent Claim
193 words
A chain saw adapted to be held by an operator using both hands comprising: a frame having, a frame handle, and a control handle; a guide rail connected to said frame; a cutting chain operably carriEd by said guide rail; power means mounted on said frame and operably connected to said cutting chain for driving said cutting chain on said guide rail; brake means operably connected to said cutting chain for stopping movement of said cutting chain on said guide rail; and brake actuation means connected to said brake means for controlling the application of said brake means including, a first lever pivotally mounted adjacent to said frame handle, a second lever pivotally mounted adjacent to said control handle, a first link connected at one end to said first lever, a second link connected at one end to said second lever, linkage means connected at one end to the other ends of said first and second links and connected at the other end to said brake means for maintaining said brake means in an actuated posture unless the first and second levers are held against the frame handle and the control handle, respectively.
Claim 3
Dependent Claim
90 words
A chain saw as defined in claim 1 wherein said linkage means comprises: a rod mounted for longitudinal translation toward and away from said brake means and connected at one end thereof to said brake means; means for normally biasing said rod toward said brake means to maintain said brake means in an actuated posture; and a third link pivotally connected at one end thereof to the other end of said rod and pivotally connected at the other end thereof to the other ends of said first and second links.
Claim 4
Dependent Claim
46 words
A chain saw as defined in claim 2 wherein said means for biasing comprises: a compression spring coaxially surrounding said rod and abutted against a frame stop at one end thereof and connected to a generally midspan portion of said rod at the other end thereof.
Claim 5
Dependent Claim
16 words
A chain saw as defined in claim 1 wherein said brake means comprises: a self-locking brake.
Claim 6
Dependent Claim
67 words
A chain saw as defined in claim 1 wherein said brake means comprises: a generally cylindrical brake drum operably connected to said cutting chain; at least one arcuately wedged-shaped brake shoe operably carried adjacent the periphery of said drum and normally biased away from engagement therewith; and at least one stationary frame lug fixedly connected to said frame and positioned adjacent said at least one brake shoe.
Claim 7
Dependent Claim
61 words
A chain saw as defined in claim 5 wherein: said at least one arcuately wedge-shaped brake shoe comprises a pair of diametrically spaced brake shoes, pivotally supported upon a yoke connected therebetween; and said at least one stationary frame comprises a pair of frame lugs each one positioned on said frame adjacent a corresponding one of said pair of brake shoes.
Claim 8
Dependent Claim
49 words
A chain saw as defined in claim 6 wherein: said other end of said linkage means is connected to the yoke of said brake means for pivoting said yoke and actuating said spaced brake shoes into and out of wedging engagement between said frame lugs and said brake drum.
Claim 9
Dependent Claim
192 words
A chain saw safety device operable to be attached to a chain saw of the type having a frame, a frame handle, a control handle, a guide rail, a cutting chain and power means mounted on the frame and operably connected to the cutting chain for driving the cutting chain upon the guide rail wherein the improvement comprises: brake means operably connected to said cutting chain for stopping movement of said cutting chain upon said guide rail; and brake actuation means connected to said brake means for controlling the application of said brake means including, a first lever pivotally mounted adjacent to said frame handle, a second lever pivotally mounted adjacent to said control handle; a first link connected at one end to said first lever, a second link connected at one end to said second lever; and linkage means connected at one end to the other ends of said first and second links and connected at the other end to said brake means for maintaining said brake means in an actuated posture unless both of said first and secoNd levers are held against the frame handle and the control handle respectively.
Claim 10
Dependent Claim
192 words
A chain saw safety device operable to be attached to a chain saw of the type having a frame, a frame handle, a control handle, a guide rail, a cutting chain and power means mounted on the frame and operably connected to the cutting chain for driving the cutting chain upon the guide rail wherein the improvement comprises: brake means operably connected to said cutting chain for stopping movement of said cutting chain upon said guide rail; and brake actuation means connected to said brake means for controlling the application of said brake means including, a first lever pivotally mounted adjacent to said frame handle, a second lever pivotally mounted adjacent to said control handle; a first link connected at one end to said first lever, a second link connected at one end to said second lever; and linkage means connected at one end to the other ends of said first and second links and connected at the other end to said brake means for maintaining said brake means in an actuated posture unless both of said first and secoNd levers are held against the frame handle and the control handle respectively.
Claim 11
Dependent Claim
90 words
A chain saw as defined in claim 8 wherein said linkage means comprises: a rod mounted for longitudinal translation toward and away from said brake means and connected at one end thereof to said brake means; means for normally biasing said rod toward said brake means to maintain said brake means in an actuated posture; and a third link pivotally connected at one end thereof to the other end of said rod and pivotally connected at the other end thereof to the other ends of said first and second links.
Claim 12
Dependent Claim
168 words
A chain saw safety device as defined in claim 9 wherein said brake means comprises: a generally cylindrical brake drum operably connected to the cutting chain; at least one arcuately wedge-shaped brake shoe operably positioned adjacent to but normally spaced from the outer periphery of said drum; at least one stationary frame lug fixedly connected with the frame and positioned adjacent said at least one brake shoe to serve as an abutment when said shoe is actuated against said drum; and a yoke pivotally mounted upon the frame and lying adjacent to said brake drum, said yoke being operable to carry said at least one arcuately wedge-shaped brake shoe and being connected to said longitudinally translatable rod, whereby actuation of said longitudinally translatable rod pivots said yoke for actuating said at least one arcuately wedge-shaped brake shoe between said at least one stationary frame lug and the outer periphery of said generally cylindrical brake drum to immediately stop rotation of said drum and movement of the cutting chain.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |