US 4,866,319 AGranted

Erasing machine

AssigneeRotex, Inc.

InventorMack W. Crutchfield

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Abstract

A hand-held, motor-driven erasing machine which operates directly from the nominal wall outlet voltage and comprises a generally tubular housing having a front portion and a rear portion which are releasably attached together. A chuck tube is mounted for rotational movement within the generally tubular housing. A DC permanent magnet motor is operatively disposed within the generally tubular housing and includes a wire-wound armature surrounding and attached to the chuck tube, a commutator whose brush surface is positioned at a right angle with respect to the rotational axis of the DC motor, a permanent magnet assembly operatively surrounding the wire-wound armature. A rectifier device is operatively connected to receive the AC voltage from the wall outlet and provide a DC output to the DC motor. A switch assembly is operatively connected between the output of the rectifier device and the DC motor.

Claims21

Dependent claims

A hand-held, motor-driven erasing machine which operates directly from the nominal wall-outlet voltage of 115-120 volts AC, said hand-held, motor-driven erasing machine comprising:

(a) a generally tubular housing means including a front portion and a rear portion;
(b) means for releasably attaching said front portion and said rear portion together;
(c) a chuck tube mounted for rotational movement within said generally tubular housing means;
(d) a 115-120 volt DC motor operatively disposed within said generally tubular housing means for rotational movement therein, said 115-120 volt DC motor comprising a wire-wound armature surrounding a predetermined portion of said chuck tube and attached thereto, a commutator whose brush surface is positioned at a right angle with respect to the rotational axis of said 115-120 volt DC motor, a permanent magnet assembly operatively surrounding said wire-wound armature, said permanent magnet assembly comprising a generally cylindrical inner sleeve and a generally cylindrical outer sleeve surrounding said generally cylindrical inner sleeve and a brush holder assembly operatively surrounding said chuck tube and positioned such that brushes mounted in said brush holder are operatively positioned against said commutator;
(e) rectifier means operatively connected to receive the 115-120 volts AC and provide an output of 115-120 volts DC to said 115-120 volt DC motor;
and
(f) a switch assembly operatively connected between said output from said rectifier means and an input to said 115-120 volt DC motor.

4 more elements

In combination with a hand-held, motor-driven machine including a generally tubular housing having a front portion and a rear portion, said front portion having an opening of predetermined size and shape in the wall thereof, a switch assembly comprising:

(a) a microswitch device structured to provide electrical continuity when activated to the "on" position;
(b) a front mounting assembly structured to be slidably received in said front portion of said generally tubular housing in a position rearwardly of said opening, said front mounting assembly structured to slidably receive said microswitch device in a predetermined portion thereof;
(c) a switch button device structured to activate said microswitch device when said switch button device is depressed from a rest position to an "on" position, said switch button device comprising a ring-like portion and a lever portion which is cantilevered from said ring-like portion at approximately eighty-five degrees;
(d) a spring device structured and positioned to bias said switch button device to the rest position.

1 more element

Dependencies are inferred from the claim text.