US2707852A - Knife sharpener - Google Patents

Description

May 10, 1955 M. FILLWEBER KNIFE SHARPENER 2 Sheets-:Sheet 1 Filed July 7, 1951 I JWMW Marcellp .ZIFzZZweber y 1955 M. 1. FILLWEBER 2,707,852

KNIFE SHARPENER Filed July 7, 1951 2 Sheets-Sheet 2 United States Patent arm-s52 snARrEnER Marcllus -I. Fillweber, Racine, Wis., assig uor to John Oster Manufacturing Company, :Racine, "-Wis., :a coreporation of wiscons'in Application July 7,, 19.51,;SeriaLNO. 23,53 .11

'4 Cla'ims. (Gl- 51-130) This .invention .relates ;to ,.knife ,sharpeners and refers more particularly to ;an .electric .motor operated .knife sharpener especially intended fonhome ,use ,andhaving a pair-of slightly overlapping abrasive sharpening wheels rotatable .inoPPDsite directions .on .parallel spaced,..apart axes.

In general, the.,objec.tiof. this invention istoprovidehan improved knife sharpenerof the ,character..descrihed having a number of .unusualrfeatures ,and. advantages, ,many of which will become apparent :from the following .description.andztheannexedclaims.

Among the more important advantages ref-the knife sharpener :of :thisi-nvention, ,however, is ithe fact .thatthe abrasive wheels areisolated .from the remainder :of .the sharpening. mechanism .in suc'ha unanner -.tha.t steelfilings and material abraded from the wheels are preventedirom entering-themechanism.

Another veryximportantadvantage .ofthelcnifesharpem er .of this .invention resides sin the .fact 1 that the motor by which the sharpening wheels care .driven .is located well to one .sideof .theaxes of .the.wheelswratherrthan in line with them, so .thatits hulk w ill, not,-interfere with proper transit of a knife blade .across the.grinding:surfacesofithe wheels.

Another .object .of v.this invention. resides -in..the provision of .a knife .sharpenenoLthe character described wherein thersharpening.mechanismis enclosedain anattrac- I tive housing, ,andwherein .thehousiug interior is divided by walls into isolated compartments .containing, ,re s pecfilyna motor, sharpening wheels,rand gearw echanism whereby rotation of-the motor--.is.-translated intonotation of the wheels, .wit-hnhe rwalls also ,providing .supportsfor a the bearings which Journal the-:.ivheel and motor shafts.

A .further advantage .of .the ,PEesentt-knife sharpener, .cotnprisingan objectofthis inventionrresidesin the novel unitary base. structure which may .be fabricated; as (a single diercasting includingtthe walls .and, zhearingsabove. referred to and to which a cover or housingtforithe sharpener and a base trim may be very readily attached.

Other objects ofthis:inventionme realized;in novel means for mounting the abrasive wheels on thei {Shafts and; novelmeansfor protectingthe bearings oft-he abrasive wheels .against the entry of r-filin gs .and.-abrasive,.dust from the-wheels.

With the above and other objects, in view, \which will appear .as the description. proceeds, this inventionfisides iu the-novel ,construction, combination and arrangement of parts substantially as hereinafter .described and more particularly -defined 1 by 1, the :ZQPPQIldEd claims, git 'being ,understood that such ,changes -in ithe precisevembodiment of the v=herei disclased invention may be :made 135 ;.com e 'withinthetscqpe of the claims.

The accompanying drawings illustrate .one complete example of the .,physic,al..embodiment,of .theinvention constructed-according, to the. bestmode so .far devisedfonthe practical application of the -principles thereof, and in which:

, verse wall 1110 oneiend .of the base.

ener of thisinvention, with a portion of the trim broken away and shown in section;

Figure 2.is .a viewsimilar .to Figure .1, but withthehousing .shown in section and .portions of. the abrasive wheels broken-away to show detail;

Figure 3 .is a top view of .the knifesharpenermechanism mounted on its .base with the .housingremovedand with ,portions of the mechanism and base .trim ,broken away .toshow detail;

Figure4 is a view similar .to Figure 2 but taken frornthe rear-of the sharpener;

.Figure 5 is a transversesectional viewtaken substantially along the plane of .theline 55..in.Figure 1 Figure 6 is a fragmentary sectional view taken substantially along the plane of the line 6-.6 in Figure .1 and Figure 7 is a .fragmentary sectional viewtaken along the plane. of the line 7-7 in Figure .2.

Referring nowto the accompanying drawings, in which like numerals designate like parts throughout .the :several views, the numeral 5 designates generally an -.elongated substantially flat horizontal base upon which the entire knife sharpener-of this .invention is mounted. This base, which is preferably fabricated as a metal die casting,wis substantially.rectangular in outline,.although its vside edges are curved ,slightlyand-itscornersare rounded to enhance its appearance.

.Ahollow 'cover6, preferably of plastic and open atits bottom, :fits onthebase and coacts therewith to provide .a housing which :encloses all .of ,theknife sharpener mechanism with theexception of the working areas of .the abrasive wheels 7. In general, the mechanism of the .knife sharpener of this invention, which is mounted on the base andenclosed within the housing, comprises an electric motor 8, the abrasive .wheels 7, drive gears .9 by-means of which rotation of the Il'lOtOfiS translated into rotation of the wheels, and .a switch 10, together with-.the necessary :wiring forthe electric motor.

A.pair of=intersecting upright walls :11 and 12, integral with the .base, .divide the interior of .the housing ,into compartments and provide supports for the motorshaft =13,and 'the shafts -14 of "the abrasive rwheels. :One wall'll extends transversely across the haserintermediate the ends thereof, while the other wall 12 extends longitudinally, intermediate the side edgesof the' base, *from the trans- The two walls thus cooperate to divide the base into three .areas .or spaces, namely: a-motor space 15 which occupies one end portion of the-base, and laterally adjacent-wheel;.and gearspaces 16 and 17, respectively, which occupy the other .end of the base -and are separated from one another by the longitudinal wall 12 and from the :motor space by the transverse wall .11. The walls cooperate with the housing to define compartments corresponding to the spaces just mentioned, and those which define the wheel compartment extend upwardlyv substantially to'the .topwall of the coverand endwise to the side walls of the cover to thus completely isolate the wheel compartment with respect v.to the other compartments.

The motor 8 may be of the shaded -pole type-.and,;is preferably mounted on the transverse wall 11 :by means of screwslS, orgothersuitable fasteners, passedthrough the field laminations :into threadedbosses 19 on said' wall. The motor has a very much eIongatedshaft 13 which extends through the transverse wall 11 into .thegear-compartment, where it parallels .the longitudinal .wall ,12. The motor shaft is journaled intspaced apart, bearings 21 and .22 carried by the walls,v one bearing21 being carried by the longitudinal wall, at the end thereof remote from the. transverse wall and the other bearing 22 being jointly carried by the two wallsrat.theirgintersection. Between the bearings the motor shaft has a sleeve 24, preferably of plastic, having a pair of oppositely threaded worms and 26 integral therewith, and this sleeve is secured to the shaft for rotation therewith, as by means of a pin 27.

The longitudinal wall also carries the bearings 28 for the abrasive wheel shafts 14 and thus mounts the wheels 7 for rotation in the wheel compartment on parallel spaced apart axes, with one wheel spaced slightly ahead of the other and their peripheries overlapping so that a knife blade drawn across the wheels will have both of its sides hollow ground simultaneously. A driven worm gear 30 is secured to the rear portion of each wheel shaft in meshing relation with one of the worms on the motor shaft, and it will be seen that by reason of the opposite threading of the worms rotation of the motor shaft in one direction is translated into rotation of the abrasive Wheels in opposite directions, the wheels moving away from one another at their tops as indicated by the arrows in Figure l. The driven worm gears, like the worms, are preferably made of plastic to eliminate the necessity for lubricating the gears.

Because the worms and driven gears are situated in the gear compartment, isolated by the longitudinal wall 12 from the wheel compartment, filings and abrasive material from the wheels cannot get into the gears to interfere with proper operation of the drive mechanism.

Each of the bearings comprises a boss 31 cast integrally with the base and walls and having a suitable bushing 32 of bearing material fitted therein. Each of the abrasive wheel bearings 28 is protected against the entry of filings and abraded material by means of a protector 33 on the abrasive wheel shaft. This protector is cup-like at its rear, having a cylindrical skirt 34 surrounding the front end portion of the boss, and its forward portion is turned down to provide an abrupt forwardly facing shoulder 35 against which the abrasive wheel seats and a tubular neck 36 on which the wheel is received and which is fixed to the wheel shaft to form a part thereof. A felt washer 37 surrounds a reduced portion 38 at the front of the boss to serve as a seal against the entry of foreign material into the bearing and is retained between a forwardly facing shoulder 39 on the boss, provided by the junction of said reduced portion with the rear of the boss, and a rearwardly facing shoulder 40 inside the skirt, defined by the junction of a bore and counterbore therein.

The abrasive wheel is retained in place on the reduced front end portion 36 of the protector and against 'the shoulder 35 by means of a speed nut 41 comprising a rectangular spring clip curved in cross section along its length (as best seen in Figure 3) and having its straight end edges firmly engaged with the front face of the wheel. The central portion of the clip is slit and apertured as at 42 (Figure 2) to provide inner tongues 43 having edge portions which engage the tubular neck 36 in front of the Wheel. Since these central edge portions are spaced from the wheel a distance such as to slightly flatten the clip from its normal curvature, they are biased into secure biting engagement with the tubular neck in consequence of the tendency of the clip to resume its normal curvature.

It will be seen that the wheel shaft is held in place in the bearing by cooperation of the driven worm gear 30 and the protector just described, with axial floating of the shaft held to a minimum by means of thrust washers 44 interposed between the bottom of the cup-like protector and the front of the boss.

Formed integrally with the base and in part defined by the upright walls is a junction box 45 in which are housed the wiring connections connecting the power supply cord 46 with the motor conductors 47, together with the electric switch 48 by means of which starting and stopping of the motor is controlled.

The base is of course apertured below the junction box to permit the cord 46 to enter the junction box, and it also has apertures 49 in the motor space for motor cooling air and apertures 49' in the wheel space to permit abraded matter and filings to drop out of the machine. To clear the supply cord and admit cooling air, the base is mounted on resilient pads 50 which raise it slightly above the surface upon which it rests. The flow of cooling air to the motor is further improved by a baffle 51 across the housing in the motor compartment, which baffle has a hole therein substantially in line with the motor armature.

The appearance of the base is enhanced by a bright chromium plated trim 52 formed as a unitary stamping comprising a skirt 53 which surrounds the edge of the base and an inwardly extending flange 54 which overlies the marginal edge portion of the top of the base. Both the base and the flange of the trim have aligned holes which receive tit-like lugs 55 on the lower edge of the cover to hold the latter in place on the base. Screws 56, inserted through aligned holes in the base and trim flange and into threaded bosses 57 at the insides of the cover corners, retain the cover in place with the trim flange clamped between its lower edge and the upper surface of the base.

The cover, as stated above, encloses all of the knife sharpener mechanisms with the exception of the working surfaces of the wheels 7. In order to provide clearance to enable a knife blade to be passed across the working surfaces of the wheels the longitudinal wall 12 is provided with a deep slot 58 opening to its top and aligned with the area in which the wheels overlap one another. The cover is provided with wall portions 59 which extend down into this slot to define a channel in which a blade to be sharpened on the wheels may be guided and which also cooperates with the longitudinal wall to close off the wheel compartment from the gear compartment.

The slot in the cover is relatively wide immediately in front of the wheels, as at 60, to admit the front end portion of the handle of a knife to be sharpened and thus permit sharpening of all of the butt end portion of the knife blade. A narrower slot 61 extends downwardly from this wide slot portion to provide further clearance for a knife blade being sharpened as the same is drawn forwardly across the wheels. Bosses 63 on the cover extend upwardly in front of the wheels to serve as partial guards for them and also to serve as a tool rest upon which a scissors blade may be steadied to enable its edge to be ground along the flat front faces of the wheels.

From the foregoing description, taken together with the accompanying drawings, it will be readily apparent that this invention provides an electric motor operated knife sharpener having a number of improvements and novel advantages, including the fact that walls within the housing of the sharpener isolate the abrasive wheels from the remainder of the mechanism to thereby preclude entry of foreign matter into the mechanism, and the same walls also provide bearing supports for the motor shaft and the wheel shafts.

I claim:

1. A knife sharpener comprising: a housing formed jointly by a body member and a shell-like cover open at its bottom; the body member having a substantially flat base snugly engaged by the bottom edge portion of the cover; upright walls on the base cooperating with it and the cover to define a wheel compartment in the housing isolated from the remainder of the housing interior; a pair of shafts journaled in one of said walls for rotation on spaced parallel axes, with one end portion of each shaft projecting into the wheel compartment and its other end portion projecting beyond the side of said wall remote from the wheel compartment; an abrasive wheel on the first-named end portion of each shaft, said wheels being axially offset with respect to one another in said wheel compartment and having their peripheral portions overlapping; said wall having a notch in line with the overlapping portions of the wheels to provide clearance for a knife ,blade aligned with the wheel axes and engaged with the wheels; said cover having an opening therein through which said overlapping portions of the wheels are exposed; gears on said other end portions of the shafts; an electric motor in the housing outside the wheel compartment; transmission means in the housing drivingly connecting the motor with said gears to translate rotation of the motor into rotation of the abrasive wheels in opposite directions, said transmission means being disposed at the side of said wall remote from the abrasive wheels; and spaced wall portions on the cover substantially parallel to the wheel axes extending substantially across the cover in line with the overlapping portions of the wheels and extending downwardly from the top wall of the cover substantially to the wheel axes, said wall portions being joined at their bottoms and defining a clearance and guidance trough for a blade to be sharpened, said trough fitting snugly in said notch in said wall to cooperate with said wall in precluding the passage of abraded matter from the wheel compartment into the transmission means.

2. The knife sharpener of claim 1, further characterized by the fact that said base has an aperture therein beneath the overlapping portions of the wheels through which abraded matter may fall out of the housing.

3. The knife sharpener of claim 1, wherein said walls are disposed at right angles to one another, with said one wall extending from the other wall to one edge of the base, and said other wall extending entirely across the base, so that said walls cooperate to define a transmission compartment in the housing, on the side of said one wall remote from the wheel compartment, but on the same side of said other wall as the wheel compartment, and a motor compartment in which the motor is mounted; and wherein said other wall has a bearing in which the motor shaft is journaled and through which the motor shaft projects into the transmission compartment.

4. The knife sharpener of claim 3 wherein said transmission means comprises worms mounted on the motor shaft, in the transmission compartment, meshing with the gears on the wheel shafts.

References Cited in the file of this patent UNITED STATES PATENTS 977,624 Guhl Dec. 6, 1910 1,375,343 Adams et al Apr. 19, 1921 1,788,634 Robinson Jan. 13, 1931 1,925,108 Nagy Sept. 5, 1933 2,124,593 Schaeffer July 26, 1938 2,228,385 Burns Jan. 14, 1941 2,259,554 Clark Oct. 21, 1941 FOREIGN PATENTS 284,010 Great Britain Jan. 20, 1928 417,928 Great Britain Oct. 8, 1934 981,178 France Jan. 10, 1951

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