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US 5,856,715 AGranted
Portable electrical power tool having a rare earth permanent magnet motor
AssigneeRyobi North America, Inc.
InventorsDavid G. Peot, Paul W. Niemela, John E. Nemazi
Life of this patent
Estimating the term…
Abstract
A power tool is provided having a housing with a handle for an operator, a rare earth permanent magnet motor oriented within the housing having a rotary output portion operatively driving an implement. The motor has a relatively high horsepower output for its size enabling the location of the motor relative to the implement and the handle to be functionally and ergonomically optimized.
Claims6
A portable electric power tool comprising:
- a housing including a handle for a user;
- an electric permanent magnet motor assembly mounted within the housing, the motor assembly having a cylindrical motor shell aligned along a motor axis, at least two permanent magnets affixed to the motor shell, an armature rotatable within the motor shell and a driveshaft affixed to the armature providing a rotary power output, wherein the permanent magnets are formed of a rare earth material resulting in a power output of at least 0.7 hp for the motor, the motor operating at an energy product of at least 10 megagauss-oersteds with the motor shell having an axial length of less than 31/2 inches and a diameter of less than 3 inches;
- and
- a rotary driven implement operatively connected to the output of the motor driveshaft, wherein the power tool has a center of gravity which falls proximate a plane defined by the rotary driven implement, the center of gravity falling on a line parallel to the rotary driven implement and aligned with the handle.
1 more element
A portable circular saw comprising:
- a housing including a handle for an operator;
- a base plate attached to the housing and having a planar surface for engaging a work piece which is adjustably positionable relative to the housing;
- an electric permanent magnet motor mounted to the housing, the motor having a cylindrical motor shell, at least two magnets mounted within the motor shell and a rotatable armature having a driveshaft output portion, the motor shell having an axial length of less than 31/2 inches and a diameter less than 31/2 inches, the magnets being formed of a composition including a substantial amount of rare earth material resulting in a power output of at least 1 hp for the motor, the motor operating at an energy product of at least 10 megagauss-oersteds;
- and
- a generally planer circular saw blade pivotally attached to the housing and rotatable driven by the motor, wherein the circular saw has a center of gravity which falls proximate a plane defined by the circular saw blade, the center of gravity falling on a line parallel to the circular saw blade and aligned with the handle.
2 more elements
Dependencies are inferred from the claim text.