Brake-device for power saws

Claim 2

Brake device for power saws, especially power chain saws comprising a friction brake for the driving mechanism of the saw, spring means tending to bring said brake to braking position, trigger means positioned on the saw at one of the handles of the saw, pawl means connected to said brake, further spring means connected to and tending to bring said pawl means into a position in which it holds said brake in a non-braking position, said trigger means being capable of moving said pawl means out of engagement with said brake and leave it free to move to the braking position under the force of said first spring means when said trigger means is moved from the normal position to the second position which it would reach when struck by the hand of the saw operator at an occasional flinging movement of the saw tool.

Claim 3

Brake device according to claim 1, wherein said brake is a brake band acting upon a cylindrical part of the driving mechanism of the saw, one end of said band as seen in the intended direction of rotation of said part of the driving mechanism having a fixed point of attachment relative to the bearing of the cylindrical part, a pivotally mounted lever connected to said first spring and the other end of said brake band and cooperating with said pawl means.

Claim 4

Brake device for power saws, especially power chain saws comprising a friction brake for the driving mechanism of the saw, spring means tending to bring said brake to braking position, trigger means positioned at one of the handles of the saw and movable between a normal position in which said brake is leaving the driving mechanism free to run and a second position in which said brake is activated, pawl means connected to said brake, further spring means connected to and capable of bringing said pawl means in a position in which it holds said brake in a non-braking position, said trigger means being capable of moving said pawl means out of engagement with said brake when said trigger means is moved from a normal position to a second position, said means comprising an arm pivotally mounted adjacent to said pawl means, an element carried by said arm outside of the pivoting axis of said arm and capable of acting upon said pawl to bring the same out its brake holding position when said arm is pivoted by the moving of the trigger means to the second position.

Claim 5

Brake device for power saws, especially power chain saws comprising a friction brake for the driving mechanism of the saw, spring means tending to bring said brake to braking position, trigger means positioned at one of the handles of the saw and movable between a normal position in which said brake is leaving the driving mechanism free to run and a second position in which said brake is activated, pawl means connected to said brake, further spring means connected to and capable of bringing said pawl means in a position in which it holds said brake in a non-braking position, said trigger means being capable of moving said pawl means out of engagement with said brake when said trigger means is moved from a normal position to a second position, said means comprising an arm pivotally mounted adjacent to said pawl means, an element carried by said arm outside of the pivoting axis of said arm and capable of acting upon said pawl to bring the same out its brake holding position when said arm is pivoted by the moving of the trigger means to the second position.

Claim 6

Brake device according to claim 3 wherein said arm carries a second element placed outside of the pivoting axis of said arm which second element, when said arm is pivoted by the moving of said trigger means to the normal position, is capable of acting upon a member of the brake to return the same to the position in which it is inactivated and further spring means tends to move said pawl means to its non-braking position.

Claim 7

Brake device for power saws which have a front handle, cover and a driving mechanism which includes a friction drive clutch provided with a cylindrical drum, and comprising a friction brake for the driving mechanism, spring means connected to and tending to bring said brake to braking position, trigger means at one of the handles of the saw movable between a normal position in which said brake is leaving the driving mechanism free to run and a second position in which said brake is activated, pawl means connected to Said brake, further spring means connected to and capable of bringing said pawl means to a position in which it is in engagement with said brake, holding the same in a non-activated position whereby the trigger means is provided to bring the pawl means out of engagement with the brake when the trigger means is moved from a normal position to a second position, said trigger means having a portion extending near to the handle and being mounted in a bearing on the cover enclosing the drum and said brake being a band brake provided to act upon the clutch drum and said band brake being enclosed and carried in the cover.

Claim 8

Brake device for power saws which have a front handle, cover and a driving mechanism which includes a friction drive clutch provided with a cylindrical drum, and comprising a friction brake for the driving mechanism, spring means connected to and tending to bring said brake to braking position, trigger means at one of the handles of the saw movable between a normal position in which said brake is leaving the driving mechanism free to run and a second position in which said brake is activated, pawl means connected to Said brake, further spring means connected to and capable of bringing said pawl means to a position in which it is in engagement with said brake, holding the same in a non-activated position whereby the trigger means is provided to bring the pawl means out of engagement with the brake when the trigger means is moved from a normal position to a second position, said trigger means having a portion extending near to the handle and being mounted in a bearing on the cover enclosing the drum and said brake being a band brake provided to act upon the clutch drum and said band brake being enclosed and carried in the cover.

Claim 9

In a power saw having a cover, supporting handle on said cover and driving mechanism drum, a drum brake device comprising a yoke pivotally mounted on said cover and extending adjacent the supporting handle, a lever pivotally mounted in said cover and having a ratchet surface, a brake band encircling the drum and connected at one end to the cover and at its other end to said lever, resilient means tending to move said brake band to a drum braking position, a pawl pivotally mounted on the cover and normally engaging said ratchet surface holding said lever in a position retaining said brake band in a non-braking position against the pull of said resilient means, second resilient means tending to hold said pawl in its ratchet surface engaging position, and said yoke having projections, one projection positioned for moving said pawl out of its ratchet surface engaging position when said yoke is pivoted from the handle and the second projection positioned for moving said lever to its non-braking position when said yoke is moved towards the handle.

Claim 10

In a power saw having a cover, supporting handle on said cover and driving mechanism drum, a drum brake device comprising a yoke pivotally mounted on said cover and extending adjacent the supporting handle, a lever pivotally mounted in said cover and having a ratchet surface, a brake band encircling the drum and connected at one end to the cover and at its other end to said lever, resilient means tending to move said brake band to a drum braking position, a pawl pivotally mounted on the cover and normally engaging said ratchet surface holding said lever in a position retaining said brake band in a non-braking position against the pull of said resilient means, second resilient means tending to hold said pawl in its ratchet surface engaging position, and said yoke having projections, one projection positioned for moving said pawl out of its ratchet surface engaging position when said yoke is pivoted from the handle and the second projection positioned for moving said lever to its non-braking position when said yoke is moved towards the handle.