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Publication numberUS3106910 A
Publication typeGrant
Publication dateOct 15, 1963
Filing dateNov 24, 1959
Priority dateNov 24, 1959
Publication numberUS 3106910 A, US 3106910A, US-A-3106910, US3106910 A, US3106910A
InventorsLi Lou Kwong
Original AssigneeLi Lou Kwong
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrical pencil cutter
US 3106910 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

06L 1963 KWONG Ll LOU 06,910

ELECTRICAL PENCIL CUTTER Filed Nov. 24, 1959 4 Sheets-Sheet 1 INVENTOR G 7 ll 45 F F 19 3 5 3 2 w s 2 O a %%...a 6 n5 2 "Wm $2, 2.1 3&2 Ill a I III. LP- E n I m 9 4 34 A 3 4 E 6 2 l4 4 i m w 4 0 m 5 4 3 L T L 4 8 w 7 k ll, liiluul Oct. 15, 1963 KWONG Ll LOU 3,106,910

ELECTRICAL PENCIL CUTTER Filed Nov. 24, 1959 4 Sheets-Sheet 2 FIG. 3 FIG. 4


Oct. 15, 1963 ELECTRICAL PENCIL CUTTER 4 Sheets-Sheet 3 Filed Nov. 24, 1959 FIG.



INVENTOR Oct. 15, 1963 KWONG Ll LOU ELECTRICAL PENCIL CUTTER 4 Sheets-Sheet 4 Filed Nov. 24, 1959 FIG. l2


A IIIIII-III INVENTOR United States Patent 3,106,910 ELECTRICAL PENCIL CUTTER Kwong Li Lou, (Iivil Air Transport Inspection Dept, Tainan, Taiwan, China Filed Nov. 24, 1959, Ser. No. 855,121 2 (Ilaims. (Cl. mil-96) This invention relates to a pencil sharpener with electric power for sharpening a pencil with a simple inserting action by one hand only.

It is an object of the invention to provide a construction for controlling the operation of electric motor automatically following a pencil insertion and draw out, moreover, it is available to different size pencils.

As a further object, the invention proposes a novel construction for disposal of pencil shavings automatically into a detachable container.

Other advantageous features will be apparent to one skilled in the art from the following description of an embodiment of the invention and from the drawings, of which:

FIGURE 1 is an elevation of an electric pencil sharpener with an electric motor at pedestal.

FIGURE 2 is an elevation of an electric pencil sharpener with an electric motor, shield case with pedestal structure partially disclosed, and the trash box in separate position.

FIGURE 3 is a section on the line 3-3 of FIGURE 2.

FIGURE 4 is a section on the line 4-4 of FIGURE 2.

FIGURE 5 is a section on the line 5-5 of FIGURE 2.

FIGURE 6 is a section on the line 6-6 of FIGURE 2.

FIGURE 7 is a section on the line 77 of FIGURE 2.

FIGURE 8 is a section on the line 83 of FIGURE 2.

FIGURE 9 is a section on the line 99 of FIGURE 2.

FIGURE 10 is a section on the line 19-10 of FIG- URE 2.

FIGURE 11 is a section on the line 11I1 of FIG- URE 3 in enlargement, (A) pencil inlet 38-11, (B) pencil inlet 38-12, (C) pencil inlet 38-0, and (D) pencil inlet 38-61.

FIGURE 12 is a section on the line 12ll2 of FIG- URE 6.

FIGURE 13 is a section on the line I3I3 of FIG- URE 10.

FIGURE 14 is an electric circuit diagram and operation embodying a part of the invention.

The electric pencil sharpener shown in FIGURES l and 2 is designed as erect-type, pencil is inserted into it for sharpening from the top. An electric motor is set at base of pedestal 21. On the base of pedestal 21 there are four countersunk holes 22 for screws to secure the unit on desk corner, or some fixture. Shield case 43 is constructed on the pedestal 21. 1

As illustrated in FIGURES 2, 3, 4, 5 and 11, on the top is a rotatable pencil inlet round-cover 38 with four different size inlets 33-11, 38-11, 38-c and 38-1i sitting in a circle. The center of the inlet-cover 38 is inserted at stud 41 and can rotate around the stud. The stud 41 is fixed at top surface of the shield case 43. A conical spring washer 40' is fixed on the top terminal of stud 41 and presses the inlet-cover 33 downwardly. On the lower side rim of the inlet-cover 38 there are four downwardly extending detents 42, while on the top surface of the case 43 there are four dimples 54 in a circle which match the four detents 42. The inlet-cover 33 is held in indexed position by the depressive force of the conical spring washer 49 to force the detents into respective dimples. The pencil inlets may be added in different sizes at the same time increasing corresponding number of dimples and detents under the same principle. Each inlet corresponds to a pair or valve-plates, inlet 38-11 to valveplates 39-11 and 39-11, inlet 38-b to valve-plates 39-!) and "ice 39-12, inlet 38-c to valve-plates 39-0 and 39-c', inlet 38-11 to valve-plates 39-11 and 39-11 respectively. Linking with spring hinges the valve-plates are installed at lower side rim of the inlets. In actuality, each valve-plate is half part of each spring hinge, the other half, 53, as indicated,

is fixed on the under side of inlet cover 38 near each inlet by rivets 64; hinge springs 63 are installed at their hingepin to keep the valve-plate tending to level and to close the lower end of each inlet. The valve-plates, therefore, can be turned down pivotally if a pencil is inserted into the inlet, and can return to level by the hinge springs action when the pencil is drawn out. They are at rightangles to each radial direction of the inlet-cover 38. 39-11, 39-b, 39-0 and 39-12 are at outer valve position, 39-11, 39-b, 39-0 and 39-11" are at inner valve position. All the valve-plates are in half-moon shapes and have different lengths in proportion to the size of the inlets, but all of them are in equal widths which permit them to have equal depth travel when they are turned down pivotally. In FIGURE 11, BC illustrates the definite depth level. In FIGURES 2 and 11, AA is the center line of pencil inlet path. At the inlet path the large size inlet shows their valve-plates far apart from A--A; the small size inlet shows their valve-plates near A-A. The pivotally turning axles of the valve-plates are also at different distances from the center line AA. The outer valve-plates are of different thicknesses. The thickness of the outer valveplate is in reverse proportion to the size of inlet. The large size inlet has thin outer valve-plate, while the small size inlet has thicker outer valve-plate, as shown in FIG- URE 11. The outer valve-plate 39-11 of the smallest size inlet 38-11 is the thickest while 39-11 of the largest size inlet 38-12 is the least thick. The thickness of them are so designed that the thicker outer valve-plate of the small size inlet will have the same effective end travel as the thin outer valve-plate of the large size inlet when they are turned down pivotally at the pencil inlet path. B-C is the definite eifective end travel. Therefore, any outer valve-plate of any size inlet travels at equal depth and reaches a definite effective end travel during matched size pencil inserted for sharpening.

A microswitch 35 is installed at the top inside corner of the case 43 by two screws 62, to control the electrical circuit of the motor. A spring actuator 37 actuates the microswitch to be On or Off by control of button 36. The lower portion 37-h of the spring actuator is secured at the bottom of the microswitch by said screws 62, the upper portion 37-11 stretches out from slot 56 on the top of the case 43 and reaches the pencil inlet path B as indicated, under the inlet-cover 38 and above pencil guide 33-11. As mentioned above B is at the definite depth and effective end travel path of any size outer valve-plate. The top terminal of the spring actuator, therefore, will be pushed outward from B to C by any outer valve-plate when it is turned down pivotally at the pencil inlet path. The spring actuator 37 then will depress the microswitch button 36, and the microswitch 35 will be in On position. In reverse, the top terminal of the spring actuator will return from C to B by its spring force when the outer valve-plate returns to level, the microswitch button will automatically spring out from the depressed position, and the microswitch will go back to Off position.

The motor 20 may be an A.C. or DC. motor. Power is supplied along plug 24, wire leads 23 and 23-11 from A.C. or DC. power source according to the motor. Before reaching the motor the power has to pass through the microswitch as shown in FIGURE 14.

As shown in FIGURES 2, 5, 6, 7, 8 and 9, a pair of worm-type cutters 25 are supported between top and bottom circular plates 34 and 26, and are turnable steadily on their axles 27. 27-1) and 27-11 are the axles top and bottom portions. 27-h are freely inserted into top cir- 3 cular plate 34; 27-12 are freely inserted into respective alined bores in the bottom circular plate 26 and pass through it. At the lower portion the axles are in collar form, as illustrated 27c. The upper portion of the top circular plate 34 is circular shelf 33 which is rotatably inserted in a bore of the top of the shield case 43, and after passing through the shield case 43 it reaches the pencil guide 33-a. Two gears 28 are installed at the bottom terminals of the two axles 27-a below the circular plate 26, within a stationary internal ring gear 57. The two gears 28 are engaged with the ring gear 57. The ring gear 57 is fixed at the pedestal structure 58 by two lock pins 44. Each lock pin is inserted in slots on the ring gear and the pedestal structure. The pedestal structure 58 is connected to the shield case 43 and pedestal 21. Gear 29 is directly engaged with shaft gear 45 of the motor 29. Shaft 30 of the gear 29 is supported at the pedestal 21 as at 31, and its top terminal is fixed at the center of the circular plate 26. In order to get low rotating speed of the worm-type cutters 25 from high rpm. of the motor, the ratio of teeth between the gear 29 and the shaft gear 45 is high. Two flexible brush-like plates 32 are installed at the rim or" the circular plate 26 and extend outward to the surface of ring plate 55 where they touch. The ring plate 55 is fixed at the inboard wall of the shield case 43 and around the circular plate 26. The circular plate 26 is located at inner side of the ring plate 55 with a downward inturned flange overlapping an upward inturned flange of the ring plate 55, as shown in FIGURE 12; the inside of the shield case, therefore, is completely partitioned into two compartments by them, the wormtype cutters in upper compartment and the gear members in lower compartment. Though closely adjacent, the circular plate rotates while the ring plate remains stable. A disposal tube 46 connected to the ring plate 55 has an inlet 46-a (FIG. 7) and outlet 47. The tube 46 is connected to lower part of the ring plate with the disposal hole 46-a on upper part of the ring plate and the disposal hole 47 through bottom of shield case. The upper portion of tube 46 is larger than its lower portion. A detachable trash box 49 is connected to the outlet 47 as will be later explained.

Since the stud 41 is located in an oflset position with respect to line AA of FIG. 2 such that the axis of each pencil aperture in cover 38 may be brought into alinement with a line defined as AA in FIG. 2 by indexing of said cover which permits easy selection of the right size inlet for pencil to be sharpened. As the pencil is inserted the following action comes in sequence: (1) The outer valve-plate of the selected pencil inlet and spring actuator depress the microswitch to On position starting the motor; (2) the shaft gear 45 of motor 29 motivates the rotation of gear 29; (3) in conjunction with the shaft 30 of the gear 29, the circular plate 26 rotates which consequently revolves the two worm-type cutters 25, two gears 23 and two flexible brush-like plates 32; the top circular plate 34 and pencil guide 33 and 33a' also rotate; (4) the stationary internal gear 57 makes the two gears 28 to rotate which in turn cause the two worm-type cutters to rotate; the pencil now is starting to be sharpened by the cutters; (6) the pencil shavings partially fall on the bottom circular plate 26. The rotating circular plate 26 makes the shavings which fall on it move outwardly to the surface of the ring plate 55 by centrifugal force; the two flexible brush-like plates brush the shavings onto the surface of the ring plate; finally the shavings will pass through the disposal hole to be stowed in the trash box.

The trash box 49 may be made in any form as desired; a paper box to be thrown away when full just like an ordinary paper cup to be thrown away after use, or the trash box may be a permanent one as designed here. The connecting mechanism between outlet 47 and inlet of trash box 49 may be in any form using any one of many general known connections. Here is only a simple case, as shown in FIGURES 2, and 13. Adjacent the outlet 47 there is a narrow concave neck ring 43. The inlet of trash box 49 has slight spring effect, on its top rim because it is formed in three strips 50 and conical form, while along its middle has a narrow concave neck ring 51. The dimension and location of both the concave neck rings 48 and 51 are matched when the trash box 49 is attached to the outlet 47. The top of the trash box is hinged with hinge-pin and springs 52 at one side wall, and is openable at the other side. The open edges are provided with rolls 6i) and 61, the upper roll 60 being of spring etfect will slide down over the lower roll 61 and will firmly close the box when the top is depressed. The hinge springs have purpose of supporting the box weight and to keep the lid down.

For high efliciency, the circular plate 26 may be modified to a dome-like shape whereby shavings may fall onto the ring plate not only by centrifugal force but by the sloping surface of the circular plate as well. The two flexible brush-like plates may be a replaceable type. The hinge springs installed on the inner valve-plates are stronger than those installed on the outer valve-plates in order to keep balance when the other valve-plates push the microswitch spring actuator and button. The interior of the thicker cutter valve-plates may be hollow. A small type indicating light for motor operation may be installed for more impressive exterior.

It is clear that my invention has no intention to include the general structures of the worm-type cutters, the gear members and the trash box; their descriptions are just for helping to understand the whole construction and operation. The construction of the small electric motor and the microswitch are also a common knowledge and are considered unnecessary to describe in detail here.

It will be understood that there may be other means with simple modification from the dilferent thickness means of the valve-plates to govern the microswitch 35.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent 1. An electric pencil sharpener comprising a motor installed on a pedestal; gear members gear-connected on said motor; cutters carried by and on said gear members; a shield case mounted on said pedestal, and shielding said gear members and said cutters; a microswitch installed within said case to link and control the electric circuit of said motor; a pencil inlet having a diameter equal to the diameter of the largest pencil which may be used, fixed on the top center of said case, through which a pencil may be extended between said cutters for sharpening; a round cover apertured with four different size pencil inlets along a circle, and rotatably mounted on the top of said case with four steady standing positions thereon; at each said steady standing position a certain size inlet of said cover being coaxial with said inlet on the top of said case, adapted to receive a certain size pencil; two valve-plates pivotally installed in the pencil inlet of the casing, the pivotal axis of the valve-plates being at right angles to the radial direction of said cover; said valve-plates being spring biased and normally tending to level and close each said inlet or" said cover, and being able to be turned down pivotally when they are selected to align with said cutters and a proper size pencil is inserted, and returnable to level by the spring effect when said pencil is drawn out; during said turning down motion the outer valve-plate of each said two valve-plates turning outward relative to said shield case, and the inner valve-plate turning inward relative to said shield case; the microswitch having a spring actuator, said spring actuator being in the path of movement of the outwardly moving valve-plate, so that the spring actuator of said microswitch being pushed by said valve-plates, actuating said microswitch to the On position, and closing the electric circuit of said motor; said spring actuator of said microswitch coming out from a slot of said case and being extended to the pencil inlet way, along the space between said cover and the top of said case; four said outer valve-plates being so arranged in four different thicknesses to match four different size pencils respectively, that each of them can push said spring actuator outward to actuate said microswitch to On position, when each of them is selected at said pencil inlet way, and a matched size pencil is inserted for sharpening.

2. An electric pencil sharpener comprising a motor installed on a pedestal; gear members gear-connected on said motor; a circular plate installed on and carried by said gear members; cutters rotatably mounted on and carried by said circular plate; a shield case fixed on said pedestal and shielding said gear members and said cutters; a stationary ring plate fixed on the inboard wall of said case and around the periphery of said circular plate; at the adjoining portion of the ring plate and circular plate, a downward inturned-flange of said circular plate slidably overlapping an upward inturned-flange of said ring plate, so that said stationary ring plate and said rotatable circular plate completely partition said cutters at the upper side of said plates,- and said gear members at the lower side of said plates in said case; a pair of brush-like plates installed at the rim of said circular plate, and extending over and slidably touching upon said ring plate; a pencil shavings disposal hole on said ring plate leading to bottom corner outlet, and a detachable container connected to said outlet.

References Cited in the file of this patent UNITED STATES PATENTS 836,712 Rush Nov. 27, 1906 889,179 Collins May 26, 1908 1,932,181 Hoffman Oct. 24, 1933 2,094,549 Miller Sept. 28, 1937 2,233,681 Swanson Mar. 4, 1941 2,408,767 Fleming Oct. 8, 1946

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US836712 *Apr 4, 1905Nov 27, 1906Delbert D RushPencil-sharpener.
US889179 *Jan 17, 1907May 26, 1908Roy V CollinsPencil-sharpener.
US1932181 *May 15, 1930Oct 24, 1933Edward C HoffmannPencil sharpener
US2094549 *Apr 7, 1936Sep 28, 1937Paul E MillerPencil sharpener
US2233681 *Apr 18, 1938Mar 4, 1941Swanson Nils HPencil sharpener
US2408767 *Jun 10, 1944Oct 8, 1946Bert M Morris CoPencil sharpener
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3712351 *Jun 2, 1970Jan 23, 1973Kuramochi SPencil sharpener
US7913402Sep 20, 2005Mar 29, 2011Acme United CorporationCoating for cutting implements
US8245407Jan 23, 2006Aug 21, 2012Acme United CorporationCoating for cutting implements
U.S. Classification144/28.5
International ClassificationB43L23/00, B43L23/02
Cooperative ClassificationB43L23/02
European ClassificationB43L23/02