US2853053A - Pencil sharpener - Google Patents

Description

Sept. 23, 1958 w. HAMILTON PENCIL SHARPENER 2 Sheets-Sheet 1 Filed July 22, 1954 Inventor W n r O t 'byA Sept. 23, 1958 W.'HAMILTON 2,353,053

I PENCIL SHARPENER Filed July 22, 1954 2 Sheets-Sheet FIG. l2. FIG. l3.

Inventor WILLIAM HAMILTON At t orney United t Patent PENCIL SHARPENER William Hamilton, Vancouver, British Columbia, Canada Application July 22, 1954, Serial No. 445,140

4 Claims. (Cl. 120-96) This invention relates to improvements in a pencil sharpener and appertains particularly to one for tapering the ends of drafting pencils and the like to provide the marking element with a flat tapered or wedge-type end for the full width of the lead or other marking element.

The usual type of pencil sharpener tapers the cylindrical lead core to a sharp axial point which in drafting is found undesirable because it wears down too quickly due to lack of surface and in wearing produces a line of increasing Width.

To overcome these deficiencies and provide a drafting lead with a longer wearing end that will produce a line of unvarying width for an extended period of use, this invention has among its objects to provide a sharpener that will simultaneously taper opposite sides of the lead to a flat end that is of the full width of the lead; that will furthermore shape the flat tapered lead so that at its end and for a distance in therefrom the opposite fiat sides thereof are substantially parallel; and that may be easily adjusted to vary the thickness of the flat, full-width end of the lead.

A further object of the invention is to provide a sharpener for forming drafting pencils with a wedge shaped end that is characterized by structural simplicity and reasonable cost of production whereby the same is rendered commercially desirable.

-To the accomplishmentof these and related objects as shall become apparent as the description proceeds, the invention resides in the construction, combination and arrangement of parts as shall be hereinafter more fully described, illustrated invthe accompanying drawings, and pointed out in the claims hereunto appended.-

The invention will be best understood and can be more clearly described when reference is had to the drawings forming a part of this disclosure wherein like characters indicate like parts throughout the several views.

In'the drawings:

Figure 1 is a horizontal section of the sharpener, as taken on line 1-1 of Figure 2;

Figure 2 is a vertical section, as taken on line 2-2 of Figure 3; and

Figure 3 is a transverse vertical section, as taken on line 3-3 of Figure 2;

Figure 4 is an enlarged detail elevation of the grinding cylinder adjustment screw;

Figures 5, 6 and 7 are an enlarged plan, side and end elevation views respectively of the screw-actuated cylinder yoke;

Figures 8 and 9 are enlarged side and end elevation of one of the grinding cylinders;

Figures 10 and 11 are an elevation and end view're spectively of the rear face plate of the sharpenerf and Figures 12 and 13 are a side elevation and end view respectively of the upper portion only of the front face plate, that for ease of assembly is preferably made in two pieces.

ice

'The embodiment of the sharpener illustrated herein will be seen to comprise a housing unit consisting of a fiat flanged attaching base 1 from which a hollow arched shaped jacket or cover 2 rises vertically, the opposite ends 2a rounding over a semicircular top 2b and the front and back 20 and 2d being flat. An interior wall or partition 3 descends from the arched top 2b to about the mid-height of the jacket and it is spaced but a short distance inside the front wall 20. A shavings receptacle '4 in the form of a small rectangular drawer rests on the base 1 and is horizontally removable through an opening 2e in the bottom of the rear wall 2d.

For guiding and properly positioning a pencil inserted in the sharpener, a vertical stack 5, open at top and bottom and rectangular in cross section, descends from above the arched top 2b to the bottom of the partition 3 to the back wall 2d. Preferably the width of the stack 5 is just sufiicient to freely receive the hexagonal stem of a conventional drafting pencil. t

The pencil sharpening, or more properly the lead grinding mechanism comprises a pair of spaced grinding wheels 6 and 7 rotatably mounted on a pair of parallel shafts 8 and 9 respectively. The wheels are each formed as wheel 6 shown in side and end elevations in Figures 8 and 9 respectively and which will be seen to consist of a roller 6a with an axial shaft-accommodating bore 6b and having peripheral gear teeth 60 providing a gear wheel at one end while a replaceable abrasive cylinder 6d snugly embraces the roller '6a for the length thereof excepting the end gear wheel portion. The shaft 8 that supports the wheel 6 is a horizontally projecting spindle or stub shaft rigidly mounted by its forward end only in the housing front 20 and so positioned that it carries the wheel transversely of the housing and with its top below the bottom of the partition 3 and its inner side substantially in line with the centre of the pencil guide 5. The second wheel 7 is correspondingly positioned on the opposite side of the projected center line of the pencil guide stack with its shaft 9 paralleling the stub shaft 8 but this second'wheel is designed to be accurately adjusted toward or away from the first wheel. To this end, the shaft 9 is supported at opposite ends in the spaced arms of a bifurcated yoke 10 slidable horizontally in confronting channels Hand 12 in the inner sides of the front 2:: and back 2d respectively of the housing jacket. An adjusting screw 13, having a knurled head 13a and a collar flange 13b on its stem at a distance spaced inwardly from said head, has its stem screwed in a threaded bore 10a in the crosshead of the yoke 10. Both for initial assembly and also the replacement of abrasive cylinders or sleeves 6d the portion of the housing back 2d including the channel 12 and for more than the height of the wheels 6 and 7 is made in theform of a dove-tailed slide 14 for the full length of the back and including a projecting handle lip 14a at one end. It is sufficient as shown particularly in Figures 10 and 11 for the dove-tail bevel 14b to occur on both upper and lower edges of the slide for only a part of the length thereof and on the corresponding part of the rear wall 2d. It is also to be noted (see Figures '1 and 2). that the jacket end 2a nearest the adjustable wheel 7 has a horizontal slot 15, to accommodate that portion of the stem of the adjusting screw 13 lying between the head 13a and the collar flange 13b, extending more than half Way from the back to the front of the jacket wall, with the rear open end of this slot being exposed when the slide 14 is removed. Thus it will be apparent that when the slide 14 is removed, the wheel 6 may he slipped on or taken off its stub shaft 8 and the adjustable wheel assembly including the wheel 7, its sliding yoke 10 and the adjustment screw 13 maybe inserted or removed with the flanged screw sliding in the horizontal slot 15 until the forward arm of the yoke seats in the front wall channel 11 and when the slide plate 14 is restored to place, and it may be secured against accidental displacement by a locking tooth 14b that engages the inside of the jacket ,end oppositethe end with the slot 15, such slide plate .serves to .retain the rollers, yoke and adjustmentscrew in proper .-place.

To operate the grinding wheels 6 .and -7, .a main drive ,gear 16 is mounted above the ,slidable grinding wheel '7 .and disposed between the partition .3 and front wall 20. It is secured to ,a shaft 17 suitably journalled in the said partition and-wall and provided with ,a .crank handle 18 on its forward end exteriorly of the front of ,the jacket. This crank driven gear 16 meshes with the gearedend of the wheel 7 whose slidable adjustment toward and away from the wheel 6 .is insufficient to interrupt proper gear meshing of the parts. Also disposed b tween the front wall 20 and the partition '3 and rotatable on a shaft 19 supported by said wall and partition is a small idler .gear 20 that meshes with boththe crank wheel 16 and the ,gear 6c on the end of grinding wheel 6,and serves to reverse the direction of rotation of the wheel 6 in relation to the direction of rotation of the wheel 7.

It has been found desirable in the construction of this pencil sharpener to have the space between adjacent or confronting circumferential sides of the grinding wheels 6 and 7 a little nearer to the .end of the housing next the fixed wheel 6 thereby allowing room for the accommodation of the yoke 10 and screw 13 on the outer side of the wheel 7 and similarly oft" centering the vertical pencil guide stack 5 whose open lower end terminating above the wheels 6 and 7 straddles the variable space .between the wheels. "The preferred location of the shafts 17 and'19 for the crank gear .16 and idler gear 20 respectivelytis on opposite sides of the pencil guide stack 5, where thickening of the partition 3 to provide greater bearing support for the shafts does not obstruct the stack.

In use, a drafting pencil that has been sharpened in the usual way with an ordinary cylindrical taper .toasharp point is inserted in the pencil guide stack 5 until thesharp pointed lead engages the parallel, oppositely rotatable abrasive cylinders 6d then as the wheels 6 and 7 are rotated in opposite directions by means of the crank 18 and meshing gears, a slight downward pressure is applied to the top of the pencil to feed the lead down between the upwardly turning abrasive cylinders, that have been adjusted by the screw 13 to give the desired spacing between the confronting circumferential "surfaces of the wheels, which spacing determines the thickness of the flat, full-width end of the lead whose'opposite sides 'are ground parallel by the wheels. Thus a sharpened lead is obtained having a work-engaging drawing end with the maximum length (equalling the diameter of the lead), the desired thickness (resulting from the prior accurate adjustment of the spacing of the wheels), and'a constant thickness that extends for a considerable length (due to the opposite faces of the lead being ground parallel and not tapered) so that the pencil may be used for a much longer time, producing a line of constant and unvarying thickness firstly because of the greater wear area of its full width end and secondly because of the fixed thickness of the parallel ground sides so that as it does wear down the'width of its'workengaging end remains unchanged.

From the'foregoing description taken in connection with the accompanying drawings, it "will be manifest'that a pencil sharpener is provided that will fulfill all the necessary requirements of such a device, but-as many changes could be made in the above description and many apparently widely different embodiments of the invention may be constructed 'within the scope of the appended claims, without departing from the spirit or scope thereof, it is intended that all matters contained in the 'said' accompanying specification and drawings shall be interpreted as illustrative and not in a limitative or restrictive sense.

Cil

Having thus described the invention, what is claimed as new is:

1. A pencil sharpener for providing a fiat, full width end on the pencil lead comprising a housing, a pair of laterally spaced grinding wheels of substantial length r0- tatably mounted in said housing on horizontal parallel shafts, means for adjustably moving one of said shafts to vary the spacing between the confronting circumferential surfaces of said grinding wheels, means for simultaneously rotating said wheels in opposite directions and a vertically elongated open ended pencil stack extending vertically through saidhousing from a point above the outside thereof to a point short of the confronting circumferential sides of said wheels thereby affording support to a pencil for a substantial part of the height thereof; wherein said vertically elongated stack is rectangular in cross section with the cross sectional length corresponding with the length of said wheels and of a .cross sectional width to slidingly accommodate yet prevent the rotation of a conventional .hexagonalstemmed drafting pencil; said wheel rotating means includinga crank-operated gear journalled in said housing directly over the movable wheel shaft and to the side of said pencil stack substantially above the lowerend thereof.

,2. A pencil sharpening device, for putting a flat full width end on the pencil lead with the oppositeflat faces thereof parallel for a substantial length and the fiat end having a desired thickness, comprising a hollow jacket with spaced front and back; a pair of shafts mounted in spaced horizontal position in said jacket; an abrasive covered ro'ller on each of said shafts whose confronting circumferential sides are normallyin closely spaced relation; means for simultaneously rotating said rollers in opposite directions; means for horizontally sliding one of said rollers toward and away.from the other to adjust the spacingbetween their confronting circumferential sides to obtain the .desired thickness on the flat end of the lead; and a pencil guide, in thesform ofa vertical vstack open at both the top and bottom ends,.disp0sed at right angles to said rollers and substantially in line with the space therebetween; wherein said roller-rotating means comprises a crank-operated main gear wheel journalled in said 'housing substantially above said horizontally adjustable roller and having meshingengagement therewith that is maintained throughout the normal adjustable horizontally sliding range of .said roller;'and'an idler pinion meshing with 'both said main gear wheel and the other of said rollers.

3. A pencil-sharpening device, "for putting a flat full width end onthepenc'il leadwith the opposite flat faces thereof parallel for a substantial length and the flat end having a desired thickness, comprising a hollow jacket withspaced front and back; a pair of shafts mounted in spaced horizontal position in said jacket; an abrasive covered roller on each of said shafts whose confronting circumferential sides are normally in closely spaced relation; meansfor simultaneously rotating said rollers in opposite directions; meanstfor horizontally sliding one of said rollers toward and away from the other to adjust the spacing between :their confronting circumferential sides to obtain the desired thickness on the flat end of the lead; .anda pencilguide, ,in the form ,ofa vertical stack open at both the top and bottom ends, disposed at right angles to said rollers and substantially in line with the space .therebetween; wherein said rollers each have a gear on one end thereof and said roller-rotating means comprising a crank-operated main gear wheel journalled in said housing to the side of and above the. lower end of. said pencilguidestack and substantially over said horizontally adjustable. roller and havingmeshing engagement with the gear thereon that is maintained throughout the normal adjustable horizontally sliding range of said roller; and an idler pinion meshing with both said main gear wheel and the gear on the other of said rollers; said adjustable roller References Cited in the file of this patent UNITED STATES PATENTS,

Reitze July 18, Fox Feb. 26, Funsch June 20, Balga Jan. 19, Theobald NOV. 7, Gerwig Apr. 14, Harrington Apr. 18,

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