Pencil sharpener

• US 6,470,929 B2
• Filed: 03/30/2001
• Issued: 10/29/2002
• Est. Priority Date: 03/30/2001
• Status: Expired due to Term

• Current Assignee: Sanford LP (Newell Brands Inc.)
• Original Assignee: Hunt Holdings, Inc.
• Inventors: Fregeolle, Gerald P.
• Primary Examiner(s): BRAY, WAYMOND D
• Application Number:
  US09/823,121
• Publication Number:
  US 20020139442A1
• Time in Patent Office: 578 Days
• Field of Search: 304/52, 304/53, 304/54, 304/55, 144/28.1, 144/28.5, 144/28.6, 144/28.7, 144/28.72
• US Class Current: 144/28.72
• CPC Class Codes: B43L 23/02 with gearing

Abstract

A pencil sharpener including a self-governing sharpening assembly, a motor for driving the sharpening assembly, and a selector guide. The selector guide defines a plurality of openings positionable for aligning pencils of various sizes with the sharpening assembly. The sharpening assembly includes a rotary blade and a shaft having a reduced diameter portion. A blade holder defines a conical cavity for receiving a pencil and is driven by a drive shaft. A stop is connected to the lower end of the shaft and is slidably mounted to the blade holder in alignment with the conical cavity and is biased by a spring member to position the reduced diameter portion of the shaft away from the bearing lug of the blade holder. Sharpening ceases when a pencil moves the stop, causing receiving of the reduced diameter portion in a bearing lug and pivoting of the rotary blade away from the pencil.

Claims

1. A pencil sharpener comprising:

a housing defining a pencil-receiving opening;

self-governing sharpening assembly mounted on said housing in alignment with said pencil-receiving opening for sharpening any pencil inserted therein;

a motor operatively connected to said sharpening assembly for driving said sharpening assembly; and

a selector guide mounted on said housing, said selector guide defining a plurality of openings, each of said openings being smaller than said pencil-receiving opening and having a unique size corresponding to one of a plurality of common pencil sizes, each of said plurality of openings being selectively positionable in alignment with said pencil-receiving opening.

2. The pencil sharpener of claim 1, further comprising:

a receptacle removably matable with said housing for receiving pencil shavings discharged from said sharpening assembly.

3. The pencil sharpener of claim 2, further comprising:

a switch mounted on said housing for engaging any pencil inserted into said pencil-receiving opening;

wherein said switch is operatively connected to said motor and said sharpening assembly for driving said sharpening assembly when said switch is activated by any pencil inserted into said pencil-receiving opening.

4. The pencil sharpener of claim 1, wherein said selector guide is rotatably mounted to said housing.

5. The pencil sharpener of claim 1, further comprising detent means for positively retaining at least one of said plurality of openings in alignment with said pencil-receiving opening.

6. The pencil sharpener of claim 5, said detent means comprising:

a detent ball outwardly biased from said housing; and

at least one recess formed on said selector guide, said at least one recess being positioned to receive said detent ball when one of said plurality of openings is in alignment with said pencil-receiving opening.

7. The pencil sharpener of claim 6, said housing further comprising:

a detent ball-receiving opening for receiving said detent ball; and

a spring member positioned within said detent ball-receiving opening for biasing said detent ball into contact with said selector guide.

8. The pencil sharpener of claim 2, further comprising:

a safety switch mounted on said housing for engagement with said receptacle when said receptacle is mated to said housing, said safety switch being operatively connected to said motor to prevent operation of said motor unless said receptacle is mated with said housing.

9. The pencil sharpener of claim 8, said receptacle comprising a key, said housing further comprising a key-receiving opening adjacent said safety switch for receiving said key when said receptacle is mated with said housing, whereby said motor is prevented from operating by said safety switch unless said safety switch is engaged by said key.

10. The pencil sharpener of claim 2, said housing further comprising a cantilevered tang having a latch portion, said receptacle further comprising a complemental notch for receiving said latch portion when said receptacle is mated with said housing.

11. The pencil sharpener of claim 2, said housing and said receptacle comprising interengageable guides for mating said receptacle to said housing.

12. The pencil sharpener of claim 11, wherein said interengageable guides comprise a guide rail and a groove for receiving said guide rail.

13. The pencil sharpener of claim 1, said self-governing sharpening assembly comprising:

a blade-supporting shaft having a lower end and an upper end, said upper end having a reduced diameter portion;

a rotary blade and a pinion carried co-axially on said shaft, said rotary blade having spiral cutting edges;

a blade holder defining a conical cavity for receiving an end of a pencil therein and having a bearing lug defining a bearing opening sized to rotatably support said upper end of said shaft, said blade holder being supported by said housing to be rotatable around an axis of said conical cavity;

an annular ring gear fixedly supported by said housing and meshing with said pinion;

a drive shaft which drives said blade holder around said axis;

a stop slidably mounted to said blade holder in alignment with said conical cavity, said stop being connected to said lower end of said shaft; and

a spring member supported by said blade holder, said spring member engaging said stop and biasing said reduced diameter portion of said shaft away from said bearing opening of said bearing lug;

whereby a pencil advanced into said conical cavity is sharpened by said rotary blade until said pencil is sufficiently sharpened, at which point said pencil moves said stop against the spring bias, causing said reduced diameter portion of said shaft to enter said bearing opening of said bearing lug, said reduced diameter portion being sized relatively to said bearing opening to allow for pivotal movement of said shaft and said rotary blade away from said pencil under influence of centrifugal force produced by rotation of said blade holder around the axis of said conical cavity.

14. The pencil sharpener of claim 13, said lower end of said shaft comprising an annular groove, said stop being connected to said lower end of said shaft by fitting with said annular groove.

15. The pencil sharpener of claim 13, wherein said drive shaft is connected to a drive gear and said blade holder is connected to a carrier gear meshing with said drive gear.

16. The pencil sharpener of claim 15, said housing further comprising a mounting bracket, said mounting bracket supporting said carrier gear, said drive shaft, and said blade holder.

17. The pencil sharpener of claim 3, wherein said switch comprises

a trigger;

and

a spring member for biasing said trigger to at least partially obstruct said pencil-receiving opening.

18. A self-governing sharpening assembly comprising:

a housing;

a blade-supporting shaft having a lower end and an upper end, said upper end having a reduced diameter portion;

a rotary blade and a pinion carried co-axially on said shaft, said rotary blade having spiral cutting edges;

a blade holder defining a conical cavity for receiving an end of a pencil therein and having a bearing lug defining a bearing opening sized to rotatably support said upper end of said shaft, said blade holder being supported by said housing to be rotatable around an axis of said conical cavity;

an annular ring gear fixedly supported by said housing and meshing with said pinion;

a drive shaft which drives said blade holder around said axis;

a stop slidably mounted to said blade holder in alignment with said conical cavity, said stop being connected to said lower end of said shaft; and

a spring member supported by said blade holder, said spring member engaging said stop and biasing said reduced diameter portion of said shaft away from said bearing opening of said bearing lug;

whereby a pencil advanced into said conical cavity is sharpened by said rotary blade until said pencil is sufficiently sharpened, at which point said pencil moves said stop against the spring bias, causing said reduced diameter portion of said shaft to enter said bearing opening of said bearing lug, said reduced diameter portion being sized relatively to said bearing opening to allow for pivotal movement of said shaft and said rotary blade away from said pencil under influence of centrifugal force produced by rotation of said blade holder around the axis of said conical cavity.

19. A pencil sharpener comprising:

a housing defining a pencil-receiving opening;

a self-governing sharpening assembly mounted on said housing in alignment with said pencil-receiving opening for sharpening any pencil inserted therein, said self-governing sharpening assembly comprising a blade-supporting shaft having a lower end and an upper end, said upper end having a reduced diameter portion, a rotary blade and a pinion carried co-axially on said shaft, said rotary blade having spiral cutting edges, a blade holder defining a conical cavity for receiving an end of a pencil therein and having a bearing lug defining a bearing opening sized to rotatably support said upper end of said shaft, said blade holder being supported by said housing to be rotatable around an axis of said conical cavity, an annular ring gear fixedly supported by said housing and meshing with said pinion, a drive shaft which drives said blade holder around said axis, a stop slidably mounted to said blade holder in alignment with said conical cavity, said stop being connected to said lower end of said shaft, and a spring member supported by said blade holder, said spring member engaging said stop and biasing said reduced diameter portion of said shaft away from said bearing opening of said bearing lug, whereby a pencil advanced into said conical cavity is sharpened by said rotary blade until said pencil is sufficiently sharpened, at which point said pencil moves said stop against the spring bias, causing said reduced diameter portion of said shaft to enter said bearing opening of said bearing lug, said reduced diameter portion being sized relatively to said bearing opening to allow for pivotal movement of said shaft and said rotary blade away from said pencil under influence of centrifugal force produced by rotation of said blade holder around the axis of said conical cavity; and

a receptacle removably matable with said housing for receiving pencil shavings discharged from said sharpening assembly.

20. The pencil sharpener of claim 19, further comprising:

a switch mounted on said housing for engaging any pencil inserted into said pencil-receiving opening; and

a motor operatively connected to said sharpening assembly and said switch for driving said sharpening assembly when any pencil is inserted into said pencil-receiving opening.

21. The pencil sharpener of claim 20, further comprising:

a selector guide mounted on said housing, said selector guide defining a plurality of openings, each of said openings being smaller than said pencil-receiving opening and having a unique size corresponding to one of a plurality of common pencil sizes, each of said plurality of openings being selectively positionable in alignment with said pencil-receiving opening.

22. A self-governing sharpening assembly comprising:

a housing;

a blade-supporting shaft having a lower end and an upper end;

a rotary blade carried co-axially on said shaft, said rotary blade having a cutting edge;

a blade holder defining a cavity for receiving an end of a pencil therein and having a bearing lug defining a bearing opening sized to rotatably support said upper end of said shaft, said blade holder being supported by said housing to be rotatable around an axis of said cavity;

a stop slidably mounted to said blade holder in alignment with said cavity, said stop being connected to said lower end of said shaft; and

a spring member supported by said blade holder, said spring member engaging said stop and biasing said shaft to an operative position in which said rotary blade is capable of sharpening a pencil advanced into said cavity;

whereby said shaft and said bearing lug are complementarily configured to pivot said shaft from said operative position to an inoperative position responsive to longitudinal translation of said shaft, and whereby a pencil advanced into said cavity is sharpened by said rotary blade until said pencil is sufficiently sharpened, at which point said pencil moves said stop against the spring bias, causing said shaft to translate longitudinally relative to said bearing lug and to pivot said shaft and said rotary blade away from said pencil into said inoperative position under influence of centrifugal force produced by rotation of said blade holder around the axis of said cavity.