ELECTRIC PENCIL SHARPENER

• US 3,678,975 A
• Filed: 03/02/1970
• Issued: 07/25/1972
• Est. Priority Date: 03/06/1969
• Status: Expired due to Term

• Current Assignee: Ituo Sugiura, Kenzi Kondou, Masakazu Imanishi
• Original Assignee: Ituo Sugiura, Kenzi Kondou, Masakazu Imanishi
• Inventors: Imanishi, Masakazu, Kondou, Kenzi, Sugiura, Ituo
• Primary Examiner(s): Juhasz, Andrew R.
• Assistant Examiner(s): Coan, James F.
• Application Number:
  US05/015,797
• Time in Patent Office: 876 Days
• Field of Search: 144/28.4,28.5,28.1,28.3,28.6,28.7,28.72
• US Class Current: 144/28.5
• CPC Class Codes: B43L 23/02 with gearing

Abstract

An electric pencil sharpener including a pencil holding unit provided with a start switch, a motor circuit to which there are connected an electric motor and rotating sharpening mechanism operated by said motor, detecting means for detecting the sharpened condition of a pencil, switching means actuated by said detecting means whereby, upon completion of the sharpening of the pencil to a desired first degree, a lamp is illuminated, and upon completion of sharpening to a second sharper degree, the switching means is operated to open the circuit of the motor to stop it with the lamp remaining illuminated, thereby indicating the end of the sharpening so as to prevent the pencil from being excessively sharpened. A flywheel is coupled to the rotating sharpening mechanism to prevent immediate ceasing of rotation thereof upon opening of the motor circuit.

Claims

1. An electric pencil sharpener comprising:

a housing;

a pencil holding unit disposed on the front inside of said housing to receive and clamp a pencil to be sharpened, said holding unit including a start switch operated upon insertion of a pencil for supplying power to said sharpener;

a motor which is energized responsive to operation of said start switch;

a cutter holder for holding a cutter at a prescribed angle of inclination;

a fly wheel coupled to said cutter holder;

gear means coupled to the rear end of saId cutter holder and engaging with a gear connected to said motor;

an operating rod slideably mounted in said cutter holder;

the position of said operating rod being a function of the degree of sharpness of the pencil;

switching means operatively coupled to the rear end portion of said operating rod which is remote from said holding unit;

said switching means including a normally open contact which is closed to cause a lamp to illuminate when the position of said operating rod corresponds to a first degree of sharpness of the pencil being sharpened, and a normally closed contact which is opened when the position of said operating rod corresponds to a second degree of sharpness which is sharper than said first degree of sharpness, said motor being coupled to said switching means to turn said motor off when said normally closed contacts are opened.

2. The sharpener according to claim 1 including means for sliding said operating rod rearwardly relative to said cutter holder responsive to the insertion of the pencil in said sharpener, the degree of sliding being a function of the depth of insertion of said pencil in said sharpener.

3. The sharpener according to claim 2 wherein said means for sliding said operating rod includes a sliding member in said cutter holder for contacting the forward end portion of said operating rod and for contacting the sharpened point of the pencil inserted in said sharpener, said sliding member sliding rearwardly responsive to increasing insertion of said pencil.

4. The sharpener according to claim 1 wherein said gear means includes a spur gear coupled to the rear of said cutter holder which is engaged with a pinion gear coupled to said motor.

5. The sharpener according to claim 4 wherein said fly wheel is a cylindrical fly wheel coaxially coupled to said spur gear.

6. The sharpener according to claim 1 wherein said pencil holding unit has a bore therein through which a pencil passes, at last three spaced leg member located about the periphery of said bore with a substantially equal spacing therebetween, said leg members being movable in a radial direction relative to said bore and each leg member having a groove therein, an annular spring arranged in said grooves for exerting a substantially equal pressure on each leg member to bias it toward the axial center of said bore, said leg members clamping the pencil inserted in said sharpener.

7. The sharpener according to claim 1 including a shavings guide cover provided in said housing to cover a planetary revolving locus of said cutter.

8. The sharpener according to claim 7 wherein said guide cover is approximately semicircular in shape.

9. The sharpener according to claim 1 wherein said cutter holder is a synthetic resin molding.

10. The sharpener according to claim 9 including a balance weight embedded in said molded synthetic resin cutter holder to eliminate vibrations upon operation hereof.

11. The sharpener according to claim 1 wherein said lamp remains illuminated when said normally closed contacts are caused to open and is extinguished upon removal of said pencil from said sharpener whereby said starting switch is rendered inoperative.

12. The sharpener according to claim 1 wherein said switching means includes a switching lever operably displacable by said operating rod for closing said normally open contacts, said lever having a protuberance which, upon further displacement of said switching lever, opens said normally closed contacts, and biasing means for biasing said switching lever away from said switch contacts.