GB2289445A

GB2289445A - Spring-driven pencil sharpener

Info

Publication number: GB2289445A
Application number: GB9409357A
Authority: GB
Inventors: Heng-Chun Ku
Original assignee: KU HENG CHUN
Current assignee: KU HENG CHUN
Priority date: 1994-05-11
Filing date: 1994-05-11
Publication date: 1995-11-22
Also published as: GB9409357D0; FR2720034A3; FR2720034B3

Abstract

A cap 1 has an opening 11 to receive a pencil, a flexible clamp 15 and a pair of rectangular holding pins (16) for retaining the pencil. A main body is formed of a pair of castings 20, each with a lateral cover 3, containing a sharpening blade set 4 and a spring-driven powering device 5 to drive the blade set to rotate and sharpen the pencil. The spring (53, Fig. 5) within the device 5 is wound-up by a cord (56) which, when released, drives the blade set 4. Ratchet mechanisms (521, 542, 551) associated with the ends of the spring provide for spring wind-up and blade set rotation. Springs 142 on posts 14 carried by the cap 1 urge a pencil retained by the cap into engagement with the blade set 4 when the cap is moved outwardly relative to the main body. <IMAGE>

Description

SPRING-DRIVEN PENCIL SHARPENER The present invention relates generally to a pencil sharpener and more particularly to a pencil sharpener which is driven by spring.

Conventionally, a pencil sharpener is driven electrically or manually. For an electric pencil sharpener, the electric power is a necessity to drive the apparatus. The requirement of electricity somehow restricts the application of the electric pencil sharpener.

For a manual pencil sharpener, it needs a user utilizing both hands to hold the sharpener and operate the sharpening blade at the same time. It may not be easy to handle, especially for children who are the most potential users.

Accordingly, the present invention seeks to provide a spring-driven pencil sharpener that overcomes the problems of the prior art.

Accordingly, the present invention provides a spring-driven pencil sharpener comprising a pencil blade set and a spring-driven powering device to drive pencil sharpening. And also, the outline of the present invention is preferably designed to form an egg-like shape for holding comfortably as well as looking nicely.

The above object, features and advantages of the invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.

Fig. 1 is a perspective view of a spring-driven pencil sharpener constructed in accordance with the present invention; Fig. 2 is an exploded perspective view of the springdriven pencil sharpener of Fig. 1; Fig. 3 is a cross-sectional view showing disengaged pencil retaining means of the spring-driven pencil sharpener in a pencil-disengaged condition; Fig. 4 is a cross-sectional view showing the pencil retaining means of the spring-driven pencil sharpener in a pencil-engaged condition; Fig. 5 is an exploded perspective view of a spring-driven powering device of the spring-driven pencil sharpener; Fig. 6 is a cross-sectional view showing the operation of the spring-driven pencil sharpener; and Fig. 7 is a cross-sectional view showing the condition when the pencil sharpening is complete with the spring-driven pencil sharpener of the spring-driven pencil sharpener.

Referring to the drawings, a spring-driven pencil sharpener assembly constructed in accordance with the present invention is shown. Particularly referring to Figs. 1 and 2, the spring-driven pencil sharpener comprises a top cap 1 shaped like an airplane nose, pencil retaining means including a flexible clamp 15, a pair of rectangular holding pins 16, and a pair of bolts 17. The cap 1 defines an internal space to receive therein the clamp 15 and is further secured by the bolts 17 from below. The cap 1 has a pair of first rectangular slots 12 oppositely formed on the side wall thereof to partly receive therein the pins 16 respectively.

The cap 1 having a round opening 11 formed at the top thereof for receiving therethrough a pencil (see Figs. 3 and 4), comprises a pair of side wings 13 extending downward from the bottom thereof and a pair of posts 14 further securely adhered to the wings 13 respectively. Each of the posts 14 comprises a flange 141 formed at a free end thereof to retain a first spring 142 thereon. The cap 1 further comprises a pair of downward interior projections lla formed thereon.

Each of the projections lla releasably engages a top rectangular recess 161 formed on each of the holding pins 16.

The clamp 15, which is preferably made of flexible metal, is shaped as a cross having a first central slot 151 formed at the intersection point for receiving therethrough the pencil, a pair of first side slots 152 formed on one branch of the cross and adjacent to two opposite side of the slot 151, a pair of second side rectangular slots 153 formed on the other branch of the cross and adjacent to two opposite side of the slot 151, and two tooth-shaped end portions 154 formed thereon. Each of two tooth-shaped end portions 154 is bent downward about the central axis of each of the second side rectangular slots 153 to be parallel to the central slot 151 so that the clamp 15 is viewed laterally as a two-layer structure. Thus, two tooth-shaped end portions 154 form a clamping slot 155 below the central slot 151 to receive the pencil therethrough and retain the pencil therein.

Each of the rectangular holding pins 16, which has a side rectangular recess 162 formed at one end thereof to securely hold the bottom layer of the two-layer structure clamp 15 therein, comprises a ball 163 formed at the other end thereof having a rough bottom for convenient grasping.

Normally, the diameter of the clamping slot 155 is smaller than that of the pencil in order to securely retain the pencil received therethrough. The height of the first rectangular slots 12 of the cap 1 is larger than that of the rectangular holding pins 16. Thus, as shown in Fig. 3, when the pins 16 are forced to swing upward to make the top recesses 161 releasably engage the interior projections lla of the cap 1 respectively, two tooth-shaped end portions 154 of the clamp 15 are moved apart so as to enlarge the clamping slot 155 for the pencil extending through. And, as shown in Fig. 4, when the pins 16 are forced to make the top recesses 161 disengage the interior projections lla, the flexible clamp 15 restores the pins 16 into their normal positions as a result of the flexibility thereof to securely hold the pencil within the clamping slot 155.

Referring to Figs. 1 and 2 again, the spring-driven pencil sharpener further comprises a housing 2 which is constructed with a couple of castings 20 to define an internal space, and a pair of lateral covers 3 which are openable for dumping pencil cuttings and in connection with the castings 20 respectively.

Within the internal space of the housing 2, the springdriven pencil sharpener comprises a pencil blade set 4 having a cone-shaped recess 41 for receiving therein the head of the pencil to be sharpened and a spring-driven powering device 5.

The pencil blade set 4 further comprises a bottom ratchet 42 formed thereon so that the spring-driven powering device 5 drives the blade set 4 to sharpen the received pencil by way of the engagement thereof with the ratchet 42.

One of the castings 20 comprises a pair of locking plates 21 extending from the inner surface thereof to be releasably locked with a pair of locking slots 21a formed on the other one of the castings 20 to form the housing 2. The housing 2 has a top opening 22 formed thereon for receiving therethrough the pencil and defines an upper chamber 23 for disposing therein the pencil blade set 4 and storing therein pencil cuttings and a lower chamber 24 for disposing therein the spring-driven powering device 5. The housing 2 further defines a pair of side chambers 25 for respectively receiving therein the posts 14, the flanges 141, and the springs 142 so that the cap 1 is movably retained thereto.

Each of the castings 20 comprises two horizontally parallel plates 27, 28 mounted thereto within the lower chamber 24. The upper plate 27 has a centered recess 271 formed thereon to be rotatably locked with the powering device 5 and the lower plate 28 is provided for supporting the powering device 5. Each of the castings 20 further comprises exterior connecting means 29 adjacent to the top opening 22 to pivotally connect the lateral cover 3 at an upper portion 31 so that the cover 3 is swingingly openable in order to dump pencil cuttings produced by the blade set 4. And, the outline of the housing 2 is preferably designed to cooperate with that of the cap 1 to form an egg-like shape for holding comfortably as well as looking nicely.

Referring to Figs. 2 and 5, the spring-driven powering device 5 comprises a ring-shaped cover 51 having a top opening 511 to receive therethrough the bottom ratchet 42 of the blade set 4 and a plurality of external lugs preferably arranged on the circumference thereof to be rotatably locked with the recess 271 of the inner plate 27 within the lower chamber 24.

The spring-driven powering device 5 comprises a rope-strain reliever 52 including a top ratchet 521 formed thereon to releasably engage the ratchet 42 so as to rotate the blade set 4 in only one direction and a bottom retaining member 522, and a second spring 53 retained by the bottom retaining member 522 at one end thereof. The spring-driven powering device 5 also comprises a fixture 54 including a top retaining member 541 extending upward therefrom to retain the other end of the second spring 53 and a bottom exterior ratchet 542. The spring-driven powering device 5 further comprises a seat 55 including an interior ratchet 551 to releasably engage the bottom exterior ratchet 542 of the fixture 54 and a rope 56 wound around and tied to the rope-strain reliever 52 at one end.The seat 55 defines an internal space to receive therein the rope-strain reliever 52, the second spring 53 in a compressed form and the fixture 54.

Fig. 6 is a cross-sectional view showing the operation of the spring-driven pencil sharpener of the present invention.

After pressing the flexible clamp 15 to enlarge the clamping slot 155 defined by two tooth-shaped end portions 154, a user inserts the pencil through the opening 11 of the cap 1, the clamping slot 155, and eventually into the recess 41 of the blade set 4 so as to dispose the head of the pencil within the blade set 4 and pulls the posts 14 of the cap 1 partially out of the side chambers 25 to have the first springs 142 compressed by the flange 141 so that the inserted pencil is securely retained under the assistance of the clamp 15. The next step is to pull the rope 56 out of the rope-strain reliever 52 so that the second spring 53 is forced to deform as a result of the retaining connection between the second spring 53 and the bottom retaining member 522 of the ropestrain reliever 52, while the fixture 54 is stationary, in order to store potential energy in the second spring 53.

Finally, when released, the rope 56 is pulled back to wind around the rope-strain reliever 52 due to the potential energy of the second spring 53 tending to restore to its original condition. Simultaneously, the top ratchet 521 of the ropestrain reliever 52 forces the bottom ratchet 42 to rotate the blade set 4 in unison with the rope-strain reliever 52 to sharpen the inserted pencil.

Fig. 7 is a cross-sectional view showing the condition when pencil sharpening is complete with the spring-driven pencil sharpener of the present invention. The first springs 142 inside the side chambers 25 are loosened to be back to the normal configurations and the cap 1 returns back to cover the housing 2.

Having described the specific preferred embodiment of the present invention with reference to the accompanying drawings, it will be appreciated that the present invention is not limited to that precise embodiment and that various changes and modifications can be effected therein by one of ordinary skill in the art without departing from the scope or spirit of the invention as defined by the appended claims.

Claims

CLAIMS:

1. A spring-driven pencil sharpener comprising a top cap having a top opening formed thereon for receiving therethrough a pencil and defining an internal space; said cap including a pair of posts securely adhered thereto in which each of said posts includes a flange formed at a free end thereof to retain a first spring thereon; retaining means receivable within the internal space of said cap for receiving said pencil therethrough and releasably retaining said pencil so that said pencil extends through said cap and said retaining means and is releasably retained by said retaining means; a blade set having a top recess formed thereon for receiving therein the head of said pencil to be sharpened and including a first bottom ratchet formed thereon; a spring-driven powering device comprising a cover having a top opening formed thereon to receive therethrough said first bottom ratchet of said blade set, a rope-strain reliever including a first top ratchet formed thereon to releasably engage said first bottom ratchet of said blade set and a bottom retaining member, a second spring retained by said bottom retaining member at one end thereof, a fixture including a top retaining member extending upward therefrom to retain the other end of said second spring and a second bottom ratchet formed thereon, a seat including an interior ratchet to releasably engage said second bottom ratchet of said fixture, and a rope wound around and tied to said rope-strain reliever at one end so that when said rope is pulled out of said rope-strain reliever, said second spring is forced to deform as a result of the retaining connection between said second spring and said bottom retaining member of said rope-strain reliever, while said fixture is stationary, in order to store potential energy in said second spring and when said rope is released to be pulled back to wind around said rope-strain reliever due to potential energy stored in said second spring tending to restore to its original condition, said first top ratchet of said ropestrain reliever forces said first bottom ratchet to rotate said blade set in unison with said ropestrain reliever to sharpen said pencil; said seat defining an internal space to receive therein said rope-strain reliever, said second spring in a compressed form, and said fixture; a housing having a top opening formed thereon for receiving therethrough said pencil and defining an internal space which has an upper chamber for securely receiving therein said blade set and storing therein pencil cuttings produced by said blade set, a lower chamber for securely receiving therein said spring driven powering device, and a pair of side chambers for receiving therein said pair of posts, said flanges, and said first springs so that said cap is movably retained thereto and when said posts are pulled partially out of said side chambers to force said first springs compressed by said flanges, said pencil is securely retained under the assistance of said retaining means; and at least one lateral cover openable for dumping said pencil cuttings and in connection with said housing.

2. A spring-driven pencil sharpener as claimed in claim 1, wherein said cap further comprises a pair of downward interior projections formed thereon to releasably engage said retaining means, having a pair of first slots oppositely formed on the side wall thereof to partly receive therein said retaining means.

3. A spring-driven pencil sharpener as claimed in claim 2, wherein said retaining means comprises a flexible clamp having a second slot formed thereon for receiving therethrough said pencil and a pair of side slots formed thereon and including two tooth shaped end portions formed thereon so that each of said end portions is bent downward about the central axis of each of said side slots to be parallel to said second slot and a two-layer structure and then said two end portions form a clamping slot below said second slot to receive said pencil therethrough and retain said pencil therein; and a pair of holding pins partly receivable within said first slots of said cap, each of which having a top slot formed thereon to releasably engage said downward interior projections of said cap respectively and a side recess formed at one end thereof to securely hold therein the bottom layer of said two-layer clamp and including a ball formed at the other end thereof having a rough bottom for convenient grasping.

4. A spring-driven pencil sharpener, substantially as hereinbefore described and with reference to the drawings.