US4059895A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Full position safety brake for portable chain saw
Assignee: Mcculloch Corp
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Filing: 1976-04-19
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Granted: 1977-11-29
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Expires: 1996-04-19
Abstract
Abstract A hand portable chain saw with a movable safety bar for actuating a chain brake has a bracket and a lineally-acting spring which together provide a detent for holding the safety bar in the nonbraking operating position, but yet accelerate the braking movement of the safety bar upon disengagement from the detent. The carrying handle for a portable chain saw encircles the top and both sides of the saw housing to enhance both operator safety and convenience. The brake-actuating safety bar on the saw has a similar wrap-around contour to ensure engagement by the operator in the event of untoward movement of the saw for essentially any sawing position.
Inventors
- 👤 Sidney Hirschkoff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:06
CPC Classifications
F; F16; F16D; F16D49/00; F16D49/08; B; B27; B27B; B27B17/00; B27B17/08; B27B17/083; F16D59/00; F16D59/02
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
243 words
In a hand portable chain saw having a housing with a carrying handle, a cutting chain, a support bar projecting forwardly from the housing for supporting the cutting chain for endless movement, motive means carried by the housing for driving the cutting chain, and a safety brake for stopping the cutting chain, the improvement in said safety brake comprising A. safety bar means mounted on said housing for swinging movement relative to a first axis and arranged to be swung forward upon being struck by an operator, said safety bar means having a wrap-around configuration extending around the top and sides of said housing forward of said carrying handle, B. a flexible brake band having a first end secured to the housing and a second end coupled to said safety bar means for movement therewith such that forward swinging of said safety bar means moves said brake band into frictional braking engagement with said motive means to stop said cutting chain, and C. a single spring member engaged between said safety bar means and the housing at a location spaced from said first axis and for exerting resilient force longitudinal to said forward direction, said spring member being arranged constantly to bias said safety bar means forward to said braking position, and further arranged to impose yieldable latching force on said safety bar means to resist forward movement of said safety bar means and thereby prevent inadvertent brake engagement with said motive means.
Claim 2
Dependent Claim
243 words
In a hand portable chain saw having a housing with a carrying handle, a cutting chain, a support bar projecting forwardly from the housing for supporting the cutting chain for endless movement, motive means carried by the housing for driving the cutting chain, and a safety brake for stopping the cutting chain, the improvement in said safety brake comprising A. safety bar means mounted on said housing for swinging movement relative to a first axis and arranged to be swung forward upon being struck by an operator, said safety bar means having a wrap-around configuration extending around the top and sides of said housing forward of said carrying handle, B. a flexible brake band having a first end secured to the housing and a second end coupled to said safety bar means for movement therewith such that forward swinging of said safety bar means moves said brake band into frictional braking engagement with said motive means to stop said cutting chain, and C. a single spring member engaged between said safety bar means and the housing at a location spaced from said first axis and for exerting resilient force longitudinal to said forward direction, said spring member being arranged constantly to bias said safety bar means forward to said braking position, and further arranged to impose yieldable latching force on said safety bar means to resist forward movement of said safety bar means and thereby prevent inadvertent brake engagement with said motive means.
Claim 3
Dependent Claim
160 words
In a hand portable chain saw having a housing with a carrying handle, a cutting chain, a support bar projecting forwardly from the housing for supporting the cutting chain for endless movement, motive means carried by the housing for driving the cutting chain, and a safety brake for stopping the cutting chain, the improvement in said safety brake comprising A. safety bar means mounted on said housing for swinging movement and arranged to be swung forward upon being struck by an operator, said safety bar means having a wrap-around configuration extending around the top and sides of said housing forward of said carrying handle, B. a flexible brake band having a first end secured to the housing and a second end coupled to said safety bar means for movement therewith such that forward swinging of said safety bar means moves said brake band into frictional braking engagement with said motive means to stop said cutting chain, and C. resiliently-acting means
Claim 4
Dependent Claim
160 words
In a hand portable chain saw having a housing with a carrying handle, a cutting chain, a support bar projecting forwardly from the housing for supporting the cutting chain for endless movement, motive means carried by the housing for driving the cutting chain, and a safety brake for stopping the cutting chain, the improvement in said safety brake comprising A. safety bar means mounted on said housing for swinging movement and arranged to be swung forward upon being struck by an operator, said safety bar means having a wrap-around configuration extending around the top and sides of said housing forward of said carrying handle, B. a flexible brake band having a first end secured to the housing and a second end coupled to said safety bar means for movement therewith such that forward swinging of said safety bar means moves said brake band into frictional braking engagement with said motive means to stop said cutting chain, and C. resiliently-acting means
Claim 5
Dependent Claim
115 words
engaged between said safety bar means and the housing for exerting resilient force longitudinal to said forward direction, and arranged constantly to bias said safety bar means forward to said braking position, and further arranged to impose yieldable latching force on said safety bar means to resist forward movement of said safety bar means and thereby prevent inadvertent brake engagement with said motive means, 2. comprising a detent member mounted to the housing for rotation relative thereto and releasably engageable with said safety bar means for applying said latching force thereto, and a lineally-acting spring engaged between said detent member and said safety bar means and providing both said bias and said yieldable latching force.
Claim 6
Dependent Claim
115 words
engaged between said safety bar means and the housing for exerting resilient force longitudinal to said forward direction, and arranged constantly to bias said safety bar means forward to said braking position, and further arranged to impose yieldable latching force on said safety bar means to resist forward movement of said safety bar means and thereby prevent inadvertent brake engagement with said motive means, 2. comprising a detent member mounted to the housing for rotation relative thereto and releasably engageable with said safety bar means for applying said latching force thereto, and a lineally-acting spring engaged between said detent member and said safety bar means and providing both said bias and said yieldable latching force.
Claim 7
Dependent Claim
52 words
In a hand portable chain saw according to claim 2, the further improvement comprising A. first shaft means mounting said safety bar means to the housing for rotation about a first axis, and B. second shaft means mounting said detent member for rotation about a second axis parallel to said first axis.
Claim 8
Dependent Claim
54 words
In a hand portable chain saw according to claim 3, the further improvement wherein A. said first shaft means locates said first axis adjacent a lowermost location on the housing, and B. said second shaft means locates said second axis spaced in the direction toward the top of the housing from said first axis.
Claim 9
Dependent Claim
48 words
In a hand portable chain saw according to claim 3, the further improvement wherein A. said safety bar means extends continuously along said wrap-around configuration between a pair of end portions, and B. said first shaft means engages said end portions for rotatably mounting said safety bar means.
Claim 10
Dependent Claim
218 words
In a hand portable chain saw having a housing, a cutting chain, a support bar projecting forwardly from the housing for supporting the cutting chain for endless movement, motive means carried by the housing for driving the cutting chain, and a safety brake for stopping the cutting chain, the improvement in said safety brake comprising A. safety bar means mounted on said housing for swinging movement about a first axis and arranged to be swung forward along a first direction upon being struck by an operator, B. a flexible brake band having a first end secured to the housing and a second end coupled to said safety bar means for movement therewith such that forward swinging of said safety bar means moves said brake band into frictional braking engagement with said motive means to stop said cutting chain, and C. a lineally-acting spring member exerting resilient force between said safety bar means and the housing at a location removed from said first axis and directed along said first direction, said spring member being arranged constantly to bias said safety bar means forward along said first direction, and further arranged to impose yieldable latching force on said safety bar means to resist movement of said safety bar means forward along said first direction and thereby prevent inadvertent brake activation.
Claim 11
Dependent Claim
218 words
In a hand portable chain saw having a housing, a cutting chain, a support bar projecting forwardly from the housing for supporting the cutting chain for endless movement, motive means carried by the housing for driving the cutting chain, and a safety brake for stopping the cutting chain, the improvement in said safety brake comprising A. safety bar means mounted on said housing for swinging movement about a first axis and arranged to be swung forward along a first direction upon being struck by an operator, B. a flexible brake band having a first end secured to the housing and a second end coupled to said safety bar means for movement therewith such that forward swinging of said safety bar means moves said brake band into frictional braking engagement with said motive means to stop said cutting chain, and C. a lineally-acting spring member exerting resilient force between said safety bar means and the housing at a location removed from said first axis and directed along said first direction, said spring member being arranged constantly to bias said safety bar means forward along said first direction, and further arranged to impose yieldable latching force on said safety bar means to resist movement of said safety bar means forward along said first direction and thereby prevent inadvertent brake activation.
Claim 12
Dependent Claim
98 words
In a chain saw according to claim 6, the further improvement wherein A. said safety brake includes detent means movable between a holding position for restraining movement of said safety bar means along said first direction and a release position allowing forward movement of said safety bar means. B. said lineally-acting spring member is arranged to bias said detent means into said holding position for imposing said yieldable latching force, and C. said detent means is movable to said release position against the bias of said spring member in response to forward movement of said safety bar means.
Claim 13
Dependent Claim
48 words
In a chain saw according to claim 7, the further improvement wherein said spring member and said detent means are arranged for increasing the bias of said spring member on said safety bar means upon movement of said detent means from said holding position to said release position.
Claim 14
Dependent Claim
57 words
In a chain saw according to claim 7, the further improvement comprising A. a first rotatable connection of said safety bar means to the housing, and B. a second rotatable connection of said detent means to the housing spaced, along a second direction transverse to said first direction, by a first distance from said first rotatable connection.
Claim 15
Dependent Claim
42 words
In a chain saw according to claim 9, the further improvement wherein said spring member is engaged between said safety bar means and said detent means at a location spaced along said second direction by a distance greater than said first distance.
Claim 16
Dependent Claim
193 words
In a hand portable chain saw having a housing, a sawing chain mounted on an arm extending forward from the housing, motive means coupled for driving the sawing chain, a safety bar rotatable relative to the housing between a braking position and an operating position, and brake means coupled with the safety bar for brakingly engaging the motive means for stopping the sawing chain and alternatively for release from the motive means, the improvement comprising A. detent-engaging means mounted for movement with the safety bar along a first direction between said braking and said operating positions thereof, B. first arm means extending longitudinal to said first direction and rotatably mounted for rotation relative to the housing about an axis different from the rotation axis of the safety bar, and having detent means for releasable latching engagement with said engaging means when the safety bar is in said operating position, and C. lineally-acting spring means engaged with said first arm means and with the safety bar for urging said arm means rotatably into said latching engagement with said engaging means, and for urging the safety bar from said operating position into said braking position.
Claim 17
Dependent Claim
193 words
In a hand portable chain saw having a housing, a sawing chain mounted on an arm extending forward from the housing, motive means coupled for driving the sawing chain, a safety bar rotatable relative to the housing between a braking position and an operating position, and brake means coupled with the safety bar for brakingly engaging the motive means for stopping the sawing chain and alternatively for release from the motive means, the improvement comprising A. detent-engaging means mounted for movement with the safety bar along a first direction between said braking and said operating positions thereof, B. first arm means extending longitudinal to said first direction and rotatably mounted for rotation relative to the housing about an axis different from the rotation axis of the safety bar, and having detent means for releasable latching engagement with said engaging means when the safety bar is in said operating position, and C. lineally-acting spring means engaged with said first arm means and with the safety bar for urging said arm means rotatably into said latching engagement with said engaging means, and for urging the safety bar from said operating position into said braking position.
Claim 18
Dependent Claim
57 words
In a hand portable chain saw according to claim 11, the further improvement comprising A. a detent bracket rotatably mounted to the housing and forming said first arm means and further providing a second arm extending transversely to said first direction, and B. wherein said spring means is engaged between said second arm and the safety bar.
Claim 19
Dependent Claim
60 words
In a hand portable chain saw according to claim 12, the further improvement wherein said safety bar comprises a U-shaped barrier, the side portions and bottom portion of which extend respectively about the sides and top of the housing, and is rotatably mounted at the end of each side portion to the housing adjacent a lowermost location on the housing.
Claim 20
Dependent Claim
67 words
In a hand portable chain saw according to claim 13, the further improvement wherein A. said spring means is located spaced from said rotatable mounting of said safety bar in the direction toward the top of the housing, and B. said detent bracket is rotatably mounted to the housing at a location intermediate said rotatable mounting of said safety bar and the location of said spring means.
Claim 21
Dependent Claim
200 words
In a hand portable chain saw having a housing with top, bottom and sides and a carrying handle; a cutting chain mounted on an arm extending forward from the housing; motive means coupled for driving the cutting chain; a safety bar mounted on the housing for swinging movement between an operating position and a braking position; and a chain brake coupled with the safety bar for brakingly engaging the motive means to stop the chain and alternatively for release from the motive means; the improvement wherein A. said carrying handle comprises a housing-encircling wrap-around handle extending about the top of the housing and about the housing sides to a substantially lowermost location thereon, B. said safety bar comprises a housing-encircling wrap-around barrier disposed forward of said carrying handle and extending at least substantially coextensively with said handle about the top and sides of the housing, and C. said chain brake includes brake control means having a spring exerting resilient force between said safety bar and the housing both for biasing said safety bar from said operating position into said braking position and for imposing a yieldable latching force on said safety bar for normally holding it in said operating position.
Claim 22
Dependent Claim
200 words
In a hand portable chain saw having a housing with top, bottom and sides and a carrying handle; a cutting chain mounted on an arm extending forward from the housing; motive means coupled for driving the cutting chain; a safety bar mounted on the housing for swinging movement between an operating position and a braking position; and a chain brake coupled with the safety bar for brakingly engaging the motive means to stop the chain and alternatively for release from the motive means; the improvement wherein A. said carrying handle comprises a housing-encircling wrap-around handle extending about the top of the housing and about the housing sides to a substantially lowermost location thereon, B. said safety bar comprises a housing-encircling wrap-around barrier disposed forward of said carrying handle and extending at least substantially coextensively with said handle about the top and sides of the housing, and C. said chain brake includes brake control means having a spring exerting resilient force between said safety bar and the housing both for biasing said safety bar from said operating position into said braking position and for imposing a yieldable latching force on said safety bar for normally holding it in said operating position.
Claim 23
Dependent Claim
81 words
In a hand portable chain saw according to claim 15, the further improvement comprising A. shaft means mounting said safety bar to said housing adjacent the bottom thereof, and B. spring-mounting means on said safety bar and on said housing and disposing said spring for applying said resilient force to said safety bar at a distance from said mounting thereof such that the span of said safety bar along such distance provides a moment arm for the force of said spring.
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) | 1980-11-28 | 1981-05-30 | 1981-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-28 | 1985-05-30 | 1985-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-28 | 1989-05-30 | 1989-11-29 | $7700.00 | Window Closed / Lapsed |