US2521165A - Pencil sharpener - Google Patents

Description

Sept. 5, 1950 H. M. HEATH 2,521,165

PENCIL SHARPENER Filed Jan. 12, 1945 INVENTOR.

ff-MHeaik/ A 7' TOR/VEY EMMA/- mi Patented Sept. 5, 1950 UNITED STATES PATENT OFFICE PENCIL SHARPENER Harry Morgan Heath, Holyoke, Mass.

Application January 12, 1945, Serial No. 572,484

- Claims.

The present invention relates to pencil sharpeners and more particularly to pencil sharpening machines of the type in which milling cutters, generally two in number, are mounted for rotation about their own axes while revolving orbitally in an assembly about a pencil.

In conventional machines of this type the cutters operate at a predetermined angle, which is generally fixed but is some times adjustable, to the pencil, and the pencil is manually or automatically fed through an opening of larger diameter than that of the average pencil into the vertex of the angle formed by the cutters. Sharpening by such an arrangement is apt to be wasteiul of the material of the pencil because the sharpening operation can generally continue after a good point has been formed and because the cutting may be eccentric of the pencil axis. It is obvious that such continued sharpening uselessly cuts away the wood and lead of the pencil without in any way improving the sharpness of the point, and of course eccentric sharpening is objectionable.

A principal object of the present invention is to provide an improvement in machines of this general type by which such waste of the pencil material and eccentric sharpening will be entirely avoided. This is accomplished by an arrangement in which removal of the material of the pencil ceases automatically when a point of predetermined sharpness has been formed on the pencil, and by use of means for automatically centering the pencil relatively to the cutters.

Another important object is to provide a cutter arrangement which will cut forwardly, toward the end to be pointed and thus with the grain of the wood, instead of backwardly, away from the end to be pointed as in the conventional devices.

Other important objects are concerned with providing a machine of the type indicated which will include a comparatively small number of parts which are individually easily and economically made and assembled, so that the cost of the machine is kept low.

Further objects are concerned with providing a machine in which the cutter assembly is made self clearing of shavings, since the arrangement of cutters and operating gears is such that the shavings tend to move away from the gears rather than toward them as in the usual constructions.

.An incidental object involves the provision of a portion of the driving gear couple for the cutters as part of the casing or housing which encases the mechanism, so that no special gear element need be provided.

Other objects comprise a novel arrangement of pencil-holding and centering means Which is unusually simple in structure and economical to make and assemble.

Other and further objects will be apparent to those skilled in the art from the following description which, taken in conjunction with the appended drawing, discloses the invention in a preferred form of embodiment.

In the accompanying drawing, in which the same reference character designates the same part in the several views,

Figure 1 is a front elevational view of a pencil sharpener constructed in accordance with the principles of the invention;

Fig. 2 is a side elevational view showing in broken lines the operating parts in the position which they assume when no pencil is in operative relation to the cutters;

Fig. 3 is a longitudinal vertical central section taken along the line 3--3 of Fig. 1 showing an unpointed pencil inserted and the parts in the position which they are thereby caused to assume;

Fig. 4 is a detail cross sectional view taken along the line 4--4 of Fig. 3, substantially normal to the longitudinal axis of the machine;

Fig. 5 is a detail cross sectional view taken along the line 55 of Fig. 3, substantially normal to the longitudinal axis of the machine;

Fig. 6 is a sectional view taken along the line B-6 of Fig. 3, along the longitudinal axis of the machine;

Fig. 7 is a detail cross sectional view, taken along the line 1-1 of Fig; 3, substantially normal to the longitudinal axis of the machine; and

Fig. 8 is a perspective view of the resilient sleeve which forms part of the tubular guide for the pencil.

These figures illustrate a preferred embodiment of the invention which can be incorporated in other and difierently modified forms of structure, all within the spirit of the invention as defined by the appended claims. Referring to the drawing, the reference numeral l0 designates a main housing or casing, best formed of stamped sheet metal or the like and made in any convenient attractive shape, preferably including a sloping front wall H and continuously curved and generally dome-shaped top, rear and side walls l2, all closed at the bottom by a floor I3. This floor may consist of a fixed portion at the rear of the housing, soldered, welded or otherwise fastened permanently to the bottom edges of the wall l2. It supports a fixed upstanding bracket casting I4 which is provided at its top with a main bearing IS the axis of which extends generally lengthwise along the center plane of the casing and slopes slightly upwardly toward the front wall H. Just below this bearing I5 the bracket I4 is provided with a rearwardly extending arm [6 which carries at its back end a transversely extending bearing H. In this latter bearing is mounted a short drive shaft H; which projects through an opening in the side wall of the casing and there terminates in a crank handle I9. A bevel gear 20 is fixed on the drive shaft, as by a set screw 2|, and meshes with a bevel pinion 22 which is similarly fixed, as by a set screw 23, on the end portion of a stub drive shaft 24, which is journaled in the bearing 15. A collar 25 is set screwed on the forward portion of the stub shaft 24 to cooperate with the bevel pinion 22 to prevent axial movement of the shaft in either direction.

It will be obvious that turning the handle l9 will rotate the stub shaft 24. This is the main drive shaft of the cutting mechanism, which latter comprises an assembly including milling cutter means, preferably in the form of two individual cutters mounted as will now be described.

Each cutter consists of a generally cylindrical element 26 axially bored for mounting on a shaft or pin 21 on which it is free to turn. Preferably two sets of cutters and pins are employed. The pins are longer than the cutters and have their ends projecting from the front and rear ends of the cutters. Each pin is ball headed at its front end, the shape here being parti-spherical as shown at 28, and the extreme rear portion of each pin is circumferentially grooved as shown at 29.

Each of the pins is mounted in the front plate 30 and in the rear plate 3| of a cage casting generally designated 32, in which the two plates are connected by spaced side arms 33 and in which the rear plate 3| is made fast at its center on the stub shaft 24, as by being made integral therewith. The front plate 30 is socketed appropriately, as at 34, to receive the ball heads of the pins 21 for pivoting movement, and the rear plate 3| is forwardly dished and provided with slots 35 to receive the rear portions of the pins for sliding movement which is more or less radial to the axis of the cage 32.

The sockets 34 in the front plate 30 are best set equidistantly around the plate, so that if two sockets are used, as in the illustrated embodiment, they have centers on a diameter of the plate, and the slots in the rear plate are best made substantially radial in direction, but actually somewhat oifset from each other, so that when two of them are employed, as in the illustrated embodiment, they will not lie along the same diameter of the rear plate but will take the direction of slightly offset chords, as best appears in Fig. 5.

The slots 35 extend from open outer ends to points near the center of the rear plate 3|, which center is made imperforate, as shown at 36. A wire spring 31 has its opposite ends hooked in the grooves 29 of the pins and resiliently urges I arms as, at an angle determined by the depth of the slots 35, as is shown in Fig. 2, but the pins and cutters can be expanded toward the more nearly parallel relation shown in Fig. 3. As will be explained hereinafter, they become thus expanded when a pencil is inserted between them for sharpening.

The machine is provided with means for receiving a pencil which is to be sharpened and for guiding and holding it in position along the axis of the cage 32. A preferred form of such means is the tubular guide element 38 which is mounted in fixed position at the front of the housing, alined with the axis of the cage 32. A convenient mode of mounting this guide includes a supplemental casing or cowling 39, of substantially hemi-spherical form, fastened at its edges by spot welding, soldering, interlocking prongs and notches, or otherwise, to the front face H of the main housing. This cowling 39 is centrally apertured and the front end of the tubular guide 38 is crimped over the margins of the aperture. The rear end of the guide is set in a central opening in the front plate 35! of the cage 32. A pencil 40 may be thrust through the guide 38, into the cage, and up against the imperforate center portion 36 of the rear plate 3|, thereby expanding the cutters from their angular relation shown in Fig. 2 to their substantially parallel relation shown in Fig. 3.

The pencil should be more or less accuratelv centered on the alined axes of the guide 38 and the cage 32, and this is conveniently accomplished by spring means associated with the tubular guide. Such spring means may take the form of generally U-shaped leaf spring elements 4!, three or four in number, set through equidistantly spaced lengthwise slots in the guide 38 and pressed inwardly by an encircling split spring sleeve 42. If desired or thought necessary, the pencil may be further held centered in. the cage 32 by the pressure of spring arms 43 standing resiliently inwardly from the cage arms as shown in Fig. 6. It will be recognized that in either of these arrangements the pencil is accurately and securely centered by holding means positioned close to the cutting zone, thus insuring a more concentric out than can be obtained with the usual construction in which a clamp is positioned at the outer end of the guide tube, too far from the cutting zone to prevent wobbling of the pencil.

The front wall II of the main housing Ill is provided with a large opening 44 through which the forward portion of the cutter assembly projects into the cowling 39. In order to cause each cutter 26 to rotate about its axis when the cutter assembly is rotated about the axis of the stub shaft 24, each cutter has fixed to its forward end, as by being made integral with it, a spur pinion 45, which meshes with the teeth of an annular or internal gear 46 cut in the opening 44 in the front wall ll of the main housing 10 through which the cutter assembly extends.

It will be evident from the foregoing that when the handle [9 is turned, the cutter assembly rotates, with each cutter traveling orbitally about the axis of the cage 32 and, due to the meshing of the pinions 45 and the gear 46, with each cutter rotating about its own axis.

The surface of each cutter is formed with a plurality of spirally cut blades, as is usual in constructions of this general type. These blades, when turned against a pencil, cut the pencil by a milling operation. It will be evident from a comparison of Figs. 2 and 3 that the cutters of the present construction are pressed angularly sidewise against the inner end portion of a pencil 40 which is seated against the stop 36, being urged into contact with the pencil by the tension of the spring 31. With rotation of the mechanism the pencil becomes cut to a conical point at its inner end as the cutters swing from their expanded position of Fig. 3 to their angula-r relation shown in Fig. 2.

If the depths of the slots 35 are selected properly to limit the maximum angle which the cutters can assume, a sharp point will have been formed when the pins 21 have become seated in the bottoms of the slots 35, and cutting of the pencil will thereupon cease, even though rotation of the cage be continued. This results from the fact that the cutters will be kept from further swinging movement toward each other by the seating of the pins 21 in the bottoms of the slots 35 and because further thrusting of the pencil into the mechanism, even if it be manually attempted, is prevented by engagement of its inner end with the stop 36.

Thus the mechanism produces apoint of predetermined sharpness and automatically terminates the cutting operation when this has been accomplished.

In order to keep the gear couple l5-46 constantly engaged, spring washers il may be interposed between the cutters 26 and the rear plate 3!. Continued engagement of the gear couple is further maintained by making the teeth fairly deep and coarse and by making the teeth of the pinions 45 axially somewhat long, so that engagement will be maintained during all of the comparatively slight angular swing of the cutters about their pivots 2834.

It will be evident that shavings from the mechanism will all be produced in the region of its rear or inner end, by a cutting operation which progresses forwardly toward the end of the pencil rather than backwardly away from the end as in the usual arrangement. This advantageously protects the pivots 2834 and the gear couple 45-46 from contamination and fouling.

Shavings drop to the bottom of the main casing l0. They can be emptied from time to time by opening a door G8 formed in the bottom of the main casing and made in general alinement with the fixed floor l3 thereof. Such door can be hinged at 45 to the lower front edge of thebracket casting I4. It is convenient to make this door self closing by incorporating a spring in the hinge 49 and to make it self sealing and capable of being latched closed by having its edges turned up as shown at 50 so as to overlap the margin 5! of the main casing walls. A snap action may be provided by means of cooperating projections and indentations on the overlapped parts.

It is believed that it will be evident from the foregoing that the construction thereby shown and described embodies the novel principles of the invention defined by the appended claims and accomplishes the various objects and produces the several advantages hereinabove set forth.

I claim:

1. A pencil sharpener comprising a milling cutter, a shaft supporting the cutter pivoted at one end for swinging movement of the shaft, means for guiding a pencil alongside of the cutter from said end, means for urging the opposite end of the cutter yieldably against the side of the pencil, and means for causing the cutter to revolve about the pencil and rotate about the axis of its shaft.

2. A pencil sharpener comprising a plurality of milling cutters, shafts supporting the cutters substantially equidistantly about an axis of revolution, pivots supporting one end of each shaft in substantially the same plane and at substantially the same radial distance from said axis for swinging movements of the shafts, means for guiding a pencil along said axis past said pivots and between the cutters, means for-urging the opposite ends of the cutters yieldably against the side of the pencil, and means for causing the cutters to revolve about the pencil and rotate about the axis of their shafts.

3. A pencil sharpener comprising a milling cutter, a shaft supporting the cutter pivoted at one end for swinging movement of the shaft, means for guiding a pencil alongside of the cutter from said end, spring means for yieldably urging the opposite end of the cutter against the side of the pencil, and means for causing the cutter to revolve about the pencil and rotate about the axis of its shaft.

4. A pencil sharpener comprising a plurality of milling cutters, shafts supporting the cutters substantially equidistantly about an axis of revolution, pivots supporting one end of each shaft in substantially the same plane and at substantially the same radial distance from said axis, means for guiding a pencil along said axis past said pivots and between the cutters, a single spring means for yieldably urging the opposite ends of all the cutters inwardly toward said axis, whereby all the cutters are yieldably biased into oblique angular cutting relation with the pencil, and means for causing the cutters to revolve about said axis and rotate about the axis of their shafts.

In a pencil sharpener, a pair of separated substantially parallel plates mounted for rotation about a common axis, a plurality of milling cutters disposed between the plates, means mounting one end of each cutter pivotally on one of the plates, means mounting the other end of each cutter on the other plate for inward swinging movement toward said axis, means urging said ends inwardly, means guiding a pencil along said axis toward the last named plate, and means for rotating the plates about said axis to cause the cutters to revolve about said axis and rotate about their axes.

6. In a pencil sharpener, a pair of separated substantially parallel plates mounted for rotation about a common axis, a plurality of milling cutters disposed between the plates, shafts for the cutters mounted pivotally on one of the plates and extending through substantially radial slots in the other plate, spring means yieldably urging the extended ends of the shafts inwardly toward said axis, means guiding a pencil along said axis toward the last named plate, and means for rotating the plates about said axis to cause the cutters to revolve about said axis and rotate about the axes of said shafts.

'7. In a pencil sharpener, a pair of separated substantially parallel plates mounted for rotation about a common axis, a plurality of milling cutters disposed between the plates, shafts for the cutters mounted pivotally on one of the plates and having their opposite ends projecting through substantially radial slots in the other plate, a single spring means bearing against all of said projected ends yieldably urging all of said ends inwardly toward said axis, means guiding a pencil along said axis toward the last named plate, and means for rotating the plates about said axis to cause the cutters to revolve about said axis and rotate about the axes of said shafts.

8. In a pencil sharpener, means for fixing a pencil against lateral movement and against endwise movement in one direction, said means having a generally cylindrical opening and including a stop for one end of the pencil, a milling cutter mounted generally parallel to the axis of the opening and having one end pivoted for swinging movement of the cutter and the other end yieldably pressed inwardly toward said axis for bearing against the side of said axis near the named end thereof, and means for causing the cutter to revolve about the pencil and rotate about its own axis.

9. In a pencil sharpener, means for fixing a pencil against lateral movement and against endwise movement in one direction, said means having a generally cylindrical opening and including a stop for one end of the pencil, a plurality of milling cutters mounted around the axis of the opening generally parallel to each other and to said axis, means pivotally mounting one end of each cutter for swinging movement of the cutter, means pressing the other end of each cutter yieldably inwardly toward said axis for bearing against the side of the pencil near the named end thereof, and means for causing the cutters to revolve about said axis and rotate about their own axes.

10. In a pencil sharpener, a front plate having a central perforation, a tubular guide for receiving a pencil endwise, said guide being alined with the perforation, a milling cutter having one end pivoted on the plate outwardly from the perforation, a rear plate having an imperforate central zone axially alined with the guide forming a stop for the pencil and having a .substantially radial slot mounting the other end of the cutter for in and out generally radial movement, means urging said last named end of the cutter inwardly, means for rotating both of said plates, and means for causing the cutter to rotate on its axis.

11. In a pencil sharpener, a front plate having a central perforation, a tubular guide for receiving a pencil endwise, said guide being alined with the perforation, a plurality of milling cutters each having one end pivoted on the plate outwardly from the perforation, a rear plate having an imperforate central zone axially alined with the guide forming a stop for the pencil and having substantially radial slots mounting the other ends of the cutters for in and out generally radial movement, means urging said last named ends of the cutters inwardly, means for rotating both of said plates, and means for causing the cutters to rotate on their axes.

12. In a pencil sharpener, a cutting assembly comprising a pair of substantially parallel plates spaced apart and mounted for rotation about a common axis, a milling cutter pivoted at one end 50 to one plate and having its other end mounted in a substantially radial slot in the other plate,

8 1 means urging the last named end inwardly in said slot, a pinion fixed with relation to the cutter near its pivoted end, a fixed internal gear meshing with said pinion, means for guiding a pencil along said axis toward the second named plate, and means for rotating the plates.

13. In a pencil sharpener, a cutting assembly comprising a pair of plates spaced apart and mounted for rotation about a common axis, a plurality of milling cutters spaced apart around the axis of the plates, each cutter being pivoted at one end to one plate and having its other end mounted in a substantially radial slot in the other plate, means urging the last named ends inwardly in said slots, a pinion fixed with relation to each cutter near its pivoted end, and a fixed internal gear meshing with said pinions for causing the cutters to rotate on their aXes when the cutting assembly is rotated on said axis.

14. In a pencil sharpener, a cutting assembly comprising a milling cutter having a pinion fixed with relation thereto near one end thereof, a rotatably mounted plate pivotally supporting said end of the cutter for swinging movement of the cutter axis angularly relatively to the plane of the plate, and a fixed internal gear meshing with said pinion in all angular positions of the cutter as it swings about its pivot.

15. In a pencil sharpener, a casing, a tubular pencil-receiving guide mounted in an opening in the casing and extending into the casing, a plate having a central perforation alined with the inner end portion of the guide, a milling cutter having one end pivoted to said plate for swinging movement of the cutter axis angularly relatively to the plane of the plate, a pinion mounted on the cutter adjacent to said end and fixed with relation thereto, and internal gear teeth formed in the casing meshing with said pivot to cause the cutter to rotate on its axis when the plate rotates on its axis.

HARRY MORGAN HEATH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 839,806 Baines Jan. 1, 1907 1,050,770 Klaber et al Jan. 14, 1913 1,171,350 Myers Feb. 8, 1916 1,305,855 Wilson June 3, 1919 1,532,167 Weiler Apr. 7, 1925 1,611,141 Fisher Dec. 14, 1926 2,146,890 Frederick Feb. 14, 1939 2,216,681 Wallett Oct. 1, 1940 2,287,247 Hoffman June 23, 1942 FOREIGN PATENTS Number Country Date 156,265 Great Britain Apr. 4, 1922

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