US 10,413,979 B2Granted

Table saw with cutting blade safety feature

AssigneesRobert Bosch Tool Corporation, Robert Bosch GmbH

InventorsAndrew Frolov, Gary L. Voong

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Abstract

A power tool has a base defining a work surface, a rotary cutting blade extending through an opening in the work surface, a drive motor for imparting rotational movement to the cutting blade and a power train coupled between the drive motor and the cutting blade to transmit rotation movement from the drive motor to the cutting blade. A swing arm assembly carries the cutting blade and is pivotably supported on the base at a pivot axis. In one aspect of the present disclosure, the power tool includes a safety system operable in response to an emergency signal that includes a mechanism for stopping the rotation of the cutting blade, whereby the rotational inertia of the cutting blade is converted after the rotation is stopped to pivoting of the swing arm assembly carrying the blade when the rotation of the blade is stopped.

Claims19

Dependent claims

A power tool comprising:

a base defining a work surface;
a rotary cutting blade extending through an opening in the work surface, said cutting blade including a drive axle;
a drive motor for imparting rotational movement to the cutting blade;
a power train coupled between the drive motor and the drive axle of the cutting blade to transmit rotational movement from the drive motor to the cutting blade;
a swing arm assembly pivotably supported on the base at a pivot axis, the swing arm assembly carrying the cutting blade and including a latch configured to support the swing arm assembly in an operating condition in which the cutting blade extends through the opening in the work surface and configured to be released to permit the swing arm assembly to pivot about the pivot axis to a safety position in which the cutting blade is beneath the work surface;
and
a safety system operable in response to an emergency signal and including a mechanism for stopping the rotation of the cutting blade, whereby the rotational inertia of the cutting blade is converted after the rotation is stopped to pivoting of the swing arm assembly carrying the blade when the rotation of the blade is stopped, wherein the mechanism for stopping rotation of the blade includes;
an auto-locking hub mounted on said drive axle and rotationally coupled to the power train;
a jam ring surrounding said auto-locking hub and rotationally fixed in relation to said drive axle and said auto-locking hub;
and
a plurality of rollers disposed between said auto-locking hub, said drive axle and said jam ring,
wherein said auto-locking hub, jam ring and rollers are configured to transmit rotation between said auto-locking hub and said drive axle in a first operating position and to lock the drive axle to the jam ring in a locking position upon a change in relative rotational speed between the auto-locking hub and said drive axle, whereby the rotation of said cutting blade is stopped in said locking position.

9 more elements

A cutting blade assembly for a power tool having a base defining a work surface, a drive motor supported by the base and operable to impart rotational motion and a power train coupled to the drive motor to transmit rotation movement from the drive motor, the cutting blade assembly comprising:

a rotary cutting blade including a drive axle couplable to the power train for rotation;
a swing arm assembly carrying the cutting blade having a pivot yoke for pivotably mounting to the base at a pivot axis and including a latch configured to support the swing arm assembly in an operating condition in which the cutting blade extends through an opening in the work surface, the latch further configured to be released to permit the swing arm assembly to pivot about the pivot axis to a safety position in which the cutting blade is beneath the work surface;
and
a safety system operable in response to an emergency signal and including a mechanism for stopping the rotation of the cutting blade, whereby the rotational inertia of the cutting blade is converted after the rotation is stopped to pivoting of the swing arm assembly carrying the blade when the rotation of the blade is stopped, wherein the mechanism for stopping rotation of the blade includes;
an auto-locking hub mounted on said drive axle and rotationally couplable to the power train;
a jam ring surrounding said auto-locking hub and rotationally fixed in relation to said drive axle and said auto-locking hub;
and
a plurality of rollers disposed between said auto-locking hub, said drive axle and said jam ring,
wherein said auto-locking hub, jam ring and rollers are configured to transmit rotation between said auto-locking hub and said drive axle in a first operating position and to lock the drive axle to the jam ring in a locking position upon a change in relative rotational speed between the auto-locking hub and said drive axle, whereby the rotation of said cutting blade is stopped in said locking position.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/230,035Filed 5 Aug 2016
Published: US 2018/0036812 A18 Feb 2018
Granted: 17 Sep 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

B23D 47/08
Sawing machines or sawing devices working with circular saw blades, characterised only by constructional features of particular parts: of devices…
B23D 45/067
With the saw blade carried by a pivoted lever: the saw blade being adjustable according to depth or angle of cut
B27B 5/381
Devices for braking the circular saw blade or the saw spindle; Devices for damping vibrations of the circular saw blade, e.g. silencing: with at…
B27G 19/008
Safety guards or devices specially adapted for wood saws; Auxiliary devices facilitating proper operation of wood saws: with sensing of human…