US2561438A - Electrically driven pencil sharpener - Google Patents

Description

y 1951 H. R. DUCHESNEAU 2,561,438

ELECTRICALLY DRIVEN PENCIL SHARPENER Filed Feb. 23, 1949 3 wu wwto o HERVE R. ,DUGHESNEA U Patented July 24, 1951 UNITED STATES PATENT OFFICE ELECTRICALLY DRIVEN PENCIL SHARPENER Herve R. Duchesneau, Hartford, Conn.

Application February 23, 1949, Serial No. 77,701

4 Claims. 1

This invention relates to improvements in electrically driven pencil sharpeners and more particularly to the switch means in the circuits thereof and the mechanism for actuating said switches.

Electrically. driven pencil sharpeners hav been devised heretofore and have included switch means in the motor circuit for energizing the motor upon a pencil being inserted within the sharpener. These switches have generally been of the type which are actuated by the side surface of a :pencil engaging a switch actuating member when the pencil is being moved into engagement with the cutters. Thus, the motor is energized before the pencil actually engages the cutters. Further, and even more disadvantageous, is the fact that the cutters will continue to cut away the pencil as long as it is held in engagement with the cutters, notwithstanding the fact that the pencil has already been sharpened as much as is possible by the sharpener.

Obviously, such characteristics of available sharpeners result in a waste of current by needlessly driving the motor with consequent needless wearing of the machine, and an even greater waste occurs in excessively cutting away useful lengths of pencils.

The objects of the present invention is to provide an electrically driven pencil sharpener having a switch which is closed to energize the motor only when a pencil is thrust into engagement with the cutters of the sharpener whereby all actuation of the cutters will be effectively used to cut away the pencil while sharpening it.

A further object of the invention is to provide in the sharpener a switch of the type which is automatically opened by an actuating member engageable with the sharpened point of a pencil when the sharpening has been completed in a predetermined manner, whereby only enough of the pencil is cut away to provide thereon a desired amount of sharpening, and further cutting of the pencil then automatically stops so as to not only save current consumption but pencil lengths as well.

Details of these objects and of the invention, as well as other objects thereof, are set forth in the following specification and illustrated in the accompanying drawings forming a part thereof.

In the drawings,

Fig. 1 is a vertical sectional view taken on the line I-l of Fig. 2 and illustrating details 2 bodying the invention; particularly the means by which the switch is actuated.

Fig. 2 is a plan view of the pencil sharpener shown in Fig. l, the upper portion of the casing being removed in said view to illustrate details of construction.

Fig. 3 is a perspective view of a pencil sharpener embodying the present invention.

Thepencil sharpener embodying the principles of the present invention comprises a bi-partite casing, one part In of the casing enclosing the motor and gear box, while the other part I2 principally comprises a chip receptacle in which an appreciable amount of chips and cuttings from the pencil, and bits of lead therefrom, may accumulate.

A wall I4 of the part II) of the casing is provided on one surface with a projecting boss I6 and the juxtaposed wall I8 of the part I2 of the casing is provided with an aperture defined by an annular flange 20 which is of suitable diameter to frictionally engage the outer surface of the boss I6 for purposes of holding part I2 of the casing removably secured to part I0 thereof. Part I2 may thus be readily removed when necessary for purposes of emptying therefrom the accumulations therein.

The surfaces of the wall It opposite that which is provided with boss I6 has another boss 22 projecting therefrom, said boss being provided centrally thereof with a cylindrical bearing 24 extending therethrough.

Said bearing 24 merges with another bearing portion 26 which is larger in diameter than bearing 24.. Adjacent bearing portion 26 and formed principally within boss I6 is a circular cavity 28 which merges with a cavity30 of still greater diameter for purposes of receiving a ring gear 32 which is fixed to the boss IB by any suitable means such as press fitting the ring gear into the circular cavity 30.

Rotatably mounted within the adjoining bearings 24 and 26 is a cylindrical shaft 34 to one end of which is secured a. frame 36. Said frame'ineludes an'enlarged cylindrical portion 36 which is rotatably received within bearing portion 26. The frame additionally comprises a preferably cylindrical portion 46 having a still larger diameter than portion 38. Spaced from the portion 40 on the frame is a, pair of legs 42 which extend in opposite directions from the central axis of the frame 36, and the end of the frame opposite the shaft 34 terminates in a cylindrical sleeve 44 having an internal diameter sufficient to receive a lead pencil. Said sleeve 44 projects through an 3 opening 46 formed in the outer wall of part l2 of the casing, said opening 48 being axially aligned with the opening in the opposite wall of part i2 which is defined by flange 28.

Cylindrical portion 40 of the frame is provided with a plurality of threaded apertures 48 extending in from one side surface of the portion 48 at a small angle to the axis of the shaft 34. The apertures 48 are equally spaced from the central axis of the shaft 34 and they also extend at equal angles to said axis. The legs 42 are also provided with cylindrical openings 58 which are equally spaced from the central axes of the shaft 3d and sleeve 54, The axes of said openings 58 are at equal angles to said central axis of the shaft 34 axes of the threaded apertures 48. V H

A plurality of cutter members 52 having helical cutting edges thereon are each provided at oneend with a spur gear 54. Said combined cutter members and gears are centrally apertured and positioned in the frame 36 between the pairs of axially aligned threaded apertures 48 and cylindrical openings 58. A shaft. 56 extends through each of the aligned pairs of threaded apertures 58 and cylindrical openings 58, as well as through the central apertures of the cutter members 52 for purposes of rotatably supporting the cutter members 52 at an angle to each other and at equal angles tothe axis of the shaft 34, as clearly shown in Fig. l. The innermost end of each shaft 56 is threaded for purposes of engaging the threads of the apertures '18 to releasably lock the shafts 58 in their operative positions. When the cutter members are mounted as described, the spur gears 54 on them mesh with the teeth of the ring gear 32.

The free end of the shaft 84 projects beyond the outer end of the boss 22 and securedthereto is a worm gear 58, said worm gear being provided with a cylindrical socket 68 which receives said end of the shaft 34. Axially aligned with the socket to is an aperture 52 having an enlarged portion 64. The shaft 3% and frame 86, together with the cutter members 52* carried thereby, are arranged to be movable as a unit a limited amount axially relative to the boss 22. Engagement of the socketed end of the worm 58 with the outer end of the boss 22 limits the axial movement of said shafted and frame 38 in one direction and the engagement of the innerend of the cylindrical portion of the frame with the inner face of the cavity 28 limits the axial movement of the shaft and frame in the opposite direction.

As can be readily seen from Fig. 1, when the relatively movable parts are disposed the positions herein illustrated, there is a slight space between the inner face of the cavity 28 and the inner end of the cylindrical portion 48 ofthe frame. The worm gear 58, as well as the shaft 3 3 and frame 36 connected thereto, are arranged to be rotatably driven by a worm 68 fixed to one end of the armature shaft 6.8 of an electric motor 18, which is secured in any suitable manner to the bottom of part 18 of the casing. In effect, the portion of the casing I 8 which encloses the worm gear 58 and worm 68 comprises a gear box 12. The motor l8, as can be clearly seen from Fig. 2, is mounted within the remaining portion of part it of the casing from that comprising the gear box '12. v

ihe motor is connectible by a circuit compris ing a flexible cord conduit M to a source of current. For purposes of convenience, the motor Ill.

should be preferably of the tym which. operates on conventional household current of 110 v., but the invention is not to be restricted thereto. If

' desired, the motor may be of the type which can be driven from electric current supplied by a battery.

Connected in the circuit of the motor and conduit M is a switch generally designated 16. Said switch 56 is preferably of the typ Which is responsive to Opening and closing movement of the order of a few thousandths of an inch. While not restricted thereto, one type of suitable switch is sold under the name Micro and, in the exemplary illustration on the several figures, comprises a pair of spring leaf members 18 and 88 having contacts 82 at one end thereof. Said leaves 18 and'88 are'insulated from each other and are connectible in said circuit. The switch is preferably enclosed within separablecasing members 84 and 86 and the switch may be secured to one wall of part 18 of the casing by any suitable means such as screws 88.

The casing member 88 is provided with an aperture 88 through which a plunger 82 extends, said plunger preferably being provided with a head which is adapted to abut the inner surface of casing member 86 as clearly shown in Fig. 1. The, plunger 92 is also. centrally apertured to receive another plunger 94, the latter being positioned to engage leaf '18 of the switch; plunger 92 being positioned to engage leaf thereof. Leaf 88 is also provided with an aperture 98 through which plunger 94 extends.

Projecting perpendicularly outward from the outer face of worm gear 58 is a thrust member 88 which is centrally apertured and headed at its inner end, said end abutting the free end of the shaft 34, as shown in Fig. 1. The head of said thrust member 88 is accommodated within the enlarged portion 64, of the aperture 82 within the worm gear 58. Thus, said headed member and enlarged portion maintain the thrust member connected to assembled worm gear 58 and shaft 34, whereby the thrust memher is rotatable as a unit therewith when the motor 18 is. energized. The outer end of the thrust member 98 engages the outer end of the plunger 92 and, when the shaft 34 is positioned within the boss 22 as shown in Fig. 1, the switch contacts 82 are separated and the motor is deenergized.

When a pencil is inserted within the sleeve 44 and the tip thereof engages cutter members 52', the thrust force imposed by the pencil upon the cutters, and consequently upon the frame 86 and shaft 34, serves to move the shaft and frame axially of the shaft a short distance, amounting preferably to between .005 inch and .010- inch, toward the left as viewed in Fig. 1. Such movement of the shaft 34' and frame38 is limted, for example, by the engagement of the inner end of cylindrical portion 48. of the frame withthe inner face of cavity 28*. Corresponding motion is imparted to the thrust member 98 and plunger 92 with resulting movement of the leaf 8!) which causes the contact 82 thereon to engage the other contact 82. circuit and and the motor will be energized to drive the worm 6t and worm gear 58 for purposes of rotating the shaft 34 and frame 36..

Such rotation causes the cutter members 52 to be rotated about their shafts 56 due tothe engagement of the gears 54 thereon with the stationary ring gear 32. Said cutters will also be rotated about the axes of shaft 34- and frame 36 As. long as contacts 82 remain in engage- Such engagement closes the ment, the motor will continueto rotate thegcut ters for purposes of sharpening a pencil: Chips and shavings from the pencil will readily drop from the cutters into the part l2 of the casing which comprises an ample receptacle for the same. l

, The thrust member 98 and shaft 34 are each provided with a small aperture extending throughout the length of each end in axial alignment with each other for purposes of accommodating a long, needle-like actuator I00 which projects at one end slightly between thegears 54 and, at the other end, engages the end of plunger 54 which is disposed within the aperture of the plunger 92. Said actuator is preferably of small diameter so that it is relatively light in weight.

After the pencil I 02 has been sharpened a predetermined amount and the pointed lead tip I04 thereof projects a predetermined amount inward from the sleeve 44, said pointed tip will engage the end of the actuator Hill which is ad-: jacent gears 54 and thrust saidactuator a very short distance axially toward the left asviewed in Fig. 1 so as to move plunger 94 and leaf 18 toward the left to cause the contacts 82 of the switch to separate by moving leaf 18 away from leaf 88. Such movement of the actuator I00 need only be of the order approximately .005 inch and such separation of the contacts will cause the motor to stop.

When the motor stops, the same will serve as asignal that the pencil has been sharpened the desired predetermined amount and the pencil is then quickly removed from the sharpener. When the righthand end of the actuator Inn is disengaged by the sharpened tip of the penciljthe leaf 18 of the switch will bias the plunger and actuator toward the right as viewed in Fig. 1, since bythat time, the pencil I82 will also have disengaged the cutter members 52 and the frame 36 and shaft 34 are likewise moved toward the right in Fig. 1 due to the biasing force of any suitable means such as a helical spring I08 which is mounted within the part of the hearing portion 28 between opposing faces of said bearing portions and cylindrical portion 38 of the shaft 34. Such movement will cause thrust member 98 to momentarily disengage the juxtaposed end of plunger 92. Since the latter is of lightweight material such as any suitable fiber or synthetic resin, the leaf 8!] of the switch is capable of moving said plunger 92 toward the right in Fig. 1. Thus, the contacts 82 of the switch will be again disposed in their normal, spaced relationship as illustrated in Fig. 1.

In view of the foregoing, it will be seen that not only are simple and durable means provided for utilizing the thrust force of a pencil for closing the switch of the circuit described above for purposes of energizing the motor to cause rotation of the cutter to sharpen a pencil, but simple and effective means are additionally provided for causing the switch to be opened after the pencil has been sharpened a desired predetermined amount, whereby the motor will then be stopped with a resulting saving in current and lengths of pencil. This has not been possible when using electrically driven pencil sharpeners presently available.

Further, the components of the present invention are relatively few in number, simple and inexpensive to manufacture, and are capable of being easily assembled. Also, the cover portion of the part ID of the casing which encloses the motor and gear box ma be'quickly removedto completely ,expose'the operating mechanism of the pencil sharpener in the event repairs or adjustments are required.

It will be understood that adjustments may be made in the distances the thrust member 98 and actuator I move so that the contacts 82 of the switch may be closed quickly immediately following the insertion of the pencil tip between the cutter members 52, and also so that the contacts may be quickly and effectivel separated at the completion of sharpening of the pencil for purposes of stopping the motor. The exemplary amounts of movement described in detail hereinabove are merely to be comidered illustrative and not restrictive.

While the invention has been illustrated and described in its preferred embodiment and has included certain details, it should be understood that the invention is not to be limited to the precise details herein illustrated and described since the same may be carried out in other ways, falling within the scope of the invention as claimed.

What I claim as my invention is:

1. An electrically driven pencil sharpener including an electric motor, a frame having at one end a shaft mounted for rotation and limited longitudinal movement, cutter means rotatably supported by said frame, drive means interconnecting said cutter means and motor and by which said frame is rotated and said cutter means actuated to sharpen a pencil when said motor is energized, and a circuit by which said motor is connectible to a source of current; in combination with switch means having relatively movable contacts and a plunger movable to close said contacts, said switch being mounted adjacent one end. of said shaft and the plunger of said switch being engageable by said end of said shaft when a pencil is thrust against the cutter means supported by said frame to' close said switch and energize said motor to cause said pencil to be sharpened by said cutter means, and an actuator movable relative to said frame and engageable at one end with said switch, the other end of said actuator being arranged to be engaged by the sharpened tip of a pencil at the completion of the sharpening thereof and moved by said sharpened tip to open said switch and stop said motor.

2. An electrically driven pencil sharpener including an electric motor, a frame having at one end a shaft mounted for rotation and limited longitudinal movement, cutter means rotatably supported b said frame, drive means interconnecting said cutter means and motor and by which said frame is rotated and said cutter means actuated to sharpen a pencil when said motor is energized, and a circuit by which said motor is connectible to a source of current; in combination with switch means having relatively movable contacts and a plunger movable to close said contacts, said switch being mounted adjacent one end of said shaft and the plunger of said switch being engageable by said end of said shaft when a pencil is thrust against the cutter means supported by said frame to close said switch and energize said motor to cause said pencil to be sharpened by said cutter means, and an actuator extending longitudinally through said shaft and plunger and movable longitudinally relative thereto, said actuator being engageable at one end with said switch and the other end being arranged to be engaged by the sharpened tip of a pencil at the completion of the sharpening thereof and moved by said sharpened tip to sepa rate the'contacts of and thereby open said switch and stop said motor. r

3. An electrically driven pencil sharpener including anelectric motor, a frame having at one end a shaft mounted for rotation and limited longitudinal movement, cutter means rotatably supported by said frame, drive means interconnecting said cutter means and motor and by which said frame is rotated and said cutter means actuated to sharpen a pencil when said motor is energized, and a circuit by which said motor is connectible to a source of current; in combination with switch meanshaving relatively movable fingers carrying contacts, a plunger associated with said switch and movable against one switch finger to close said contacts, said switch being mounted adjacent one end of said shaft and said plunger being engageable by said endof said shaft when a pencil is thrust against the cutter means to close the contacts of said switch and energize said motor to cause said pencil to be sharpened by said cutter means, and a needlelike actuator extending longitudinall through said shaft and plunger and movable longitudinally relative thereto, said actuator being engageable at one end with the other switch finger and the other end thereof being engageable by the sharpened tip of a pencil at the completion of the sharpening thereof and movable by said sharpenedtip against said other switch finger to open said switch and stop said motor.

4- An electrically driven pencil sharpener ineluding an electric motor, a frame having at one end a shaft mounted for rotation and limited longitudinal movement, cutter means rotatably supported by said frame, and a circuit by which said motor is connectible to a source of current; in combination with means supporting said frame, a worm driven by said motor, a worm gear 8 fixed" to said frame and 'engage'able" wan-said worm, the axes of said worm and worm gear being substantially at a right angle to each other so as to permit limited movement of said gear relative to said worm in a directiontransverse to the axis of said worm, a switch havingrelatively movable contacts and mounted adjacent oneend'of said shaft, a plunger movable rela tive to said switch and interengageable with'one of said contacts, said plunger being engageable with said one end of said shaft when a pencil is thrust against the cutter means supported by said frame to move said one contact into engagement with said other contact and close-- said switch to energize said motor and cause said pencil to be sharpened by said cutter means, means on said frame engageable with fixedmeans on said support means to limit longitudinal movement' of said one end of said shaft andplunger, and' an actuator movable longitudinally of said frame and: interengageable at one end withthe other switch contact, the other end of said actuator being arranged to be engaged by the sharpened tip of a pencil at the completion of the sharpening thereof and be moved by saidisharpened tip toseparate said contactsof and open said switch to stop said motor.

HERVE R. DUCHESNEAU.

REFERENCES cI'rED The following references are of record the file of this patent: a

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