US2722783A - Knife sharpener - Google Patents

Description

L. O'RUSSA KNIFE SHARPENER Nov'. 8, 1955 2 Sheets-Sheet 1 Filed Maren ,27,Y 195s Nov. 8, 1955 l. oRussA KNIFE SHARPENER Filed March 27, 1953 2 Sheets-Sheet 2 United States Patent@ KNIFE SHARPENER Lorence ORussa, Peoria, Ill. Application Marc-1127, 1953, serialNo. 342:;937 1 Claim. (Cl. s110z) My invention relates generallyto knife and scissors Sharpeners, and particularly to those designed for domestic use.

It is an object of my invention toA provide' a motor driven Sharpener for scissors as wellk as knives, inwhich improved guide means are provided' for assuring that`- the edge of the cutting instrument will be ground at the proper angle.

A further object is to provide an improved domestic knife and scissors Sharpener in which the grinding wheel is partially enclosed to reduce to a minimum the escape of sparks.

A further object is to provide an improved domestic knife and scissors Sharpener which is light in weight, of simple construction, and which may be manufactured economically.

Other objects will appear from the following description, reference being had to the accompanying drawings, in which Fig. 1 is a side elevation of the Sharpener;

Fig. 2 is a plan view thereof, a portion of the grinding wheel enclosure being broken away to show the Wheel;

F ig. 3 is an end elevational View thereof;

Fig. 4 is a fragmentary sectional view showing the means by which the wheel enclosure is secured to the body of the Sharpener;

Fig. 5 is a vertical sectional view showing the method of mounting the motor;

Fig. 6 is a bottom plan view of a portion of the Sharpener;

Fig. 7 is a bottom plan view with the bottom plate removed;

Fig. 8 is an elevational view of a modified form of wheel enclosure, Shown to a reduced scale;

Fig. 9 is a front elevational view of a second modified form of enclosure for the grinding wheel; and

Fig. 10 is a side elevational view of the enclosure shown in Fig. 9.

The knife Sharpener comprises a body 20, preferably formed as an integral plastic molding, having a hollow handle portion 22 into which an extension cord 24 may be tucked, and a motor housing portion 23. The body 20 has a plurality of vertical ribs 26 formed integrally therewith. These ribs terminate short of the bottom edge of the body, and are provided for the reception of screws 30 used to fasten a metal plate 32 to the body. The body is provided with suitable louver openings 34 for the ventilation of a motor 36 which is secured to the metal plate 32 by screws 38. A fan 40 is secured to the lower end of the motor Shaft 42 and forces air admitted through openings 44 in the bottom plate 32 past the motor and A outwardly through louvers 34. The bottom plate is also l.provided with a keyhole slot 46 for the reception of the ahead of a screw or nail so that the Sharpener may be hung against a wall when not in use.

The upper end of the motor shaft 42 extends through the top 51 and has a grinding Wheel 48 suitably secured thereto. The wheel is preferably of the type having ICC beveled side-faces; A ped() of felto'r the" like sui-rounds' the, shaft 42 and is pressed@ againstrv the body 20 around the opening through'fwhiich the shaft'y 42 projects, by'Y a compression coil spring 52 resting on th'e" frame ofthe motor 36. This 4pad thus prevents emery dust fromL falling into the motor bearings.-

The wheel 48 is'protectediby a dme-shaped guide and guard 54, preferably madeof a` transparentplastic'. ThisVA guide and guard is detachably securedftlthe'bd'y 2`0i`by S1l of the body 20.

The guide'and guard 54h-provided withjapair of slots 62 and 63 for thereiception of the blade offa knife to bei*y sharpened. These'slotsdeneplneslongitudinal thereofl at an angle often d'eg'rieesy'vitliL respect tothe horiz'or'ial, and are so positioned and conformed that a knife blade inserted in either of them and drawn past the grinding wheel 48 will engage the bevel portion of the sides of the wheel, and thus will be ground at the proper angle. The guide and guard 54 is also provided with a slot 66 which is at an angle of seven degrees relative to` the vertical, this slot being provided to guide the blade of a pair of scissors so that its cutting edge will be ground at the proper angle.

A Suitable switch 70 is mounted on the motor 36 and is actuated by a push button 72 which is located in such position that it may be operated by the thumb of the user while his hand rests on the handle portion 22 of the grinder.

The motor rotates counterclockwise, as viewed from the top, so that in using the grinder the knife blade is preferably placed in the slot 62 and drawn slowly toward the left (Fig. 3) to grind one surface of the cutting edge, and then placed in the slot 63 and again drawn toward the left to grind the other surface of the cutting edge. The slots 62 and 63 are so positioned that the surface adjacent the cutting edge of the knife will contact the beveled surfaces of the sides of the wheel.

In grinding the blades of a pair of scissors, the surface of the blade which shears against the other blade is held against the left-hand (Fig. 1) edge of the slot 66 and drawn toward the left (Fig. 3) to assure sharpening the cutting edge at the proper angle.

By virtue of the fact that the grinding wheel is at the upper end of the vertical rotor shaft, and because of the fact that the guide and guard is made of a transparent plastic, the user of the Sharpener may observe the position of the knife blade during the grinding operation.

The guide and guard of the form shown in Fig. 8 mayV be used in place of that shown in Figs. l to 5. It comprises a tube having deep knife guiding slots 82 and S3 formed therein and a scissors blade guiding slot 84. This form of guide and guard is designed for use with a smaller diameter grinding wheel than that shown in the preferred embodiment of the invention.

The guide 86 shown in Figs. 9 and 10 is likewise in the form of a metal tube, and has guiding surfaces 88 and 89 for engagement with knife blades when grinding one side thereof, and surfaces 90 and 91 for use when grinding the other side of the cutting edge. The guide 86 also has a pair of aligned vertical slots 94, one edge 96 of each of these slots being at an angle of seven degrees with respect to the vertical so that the cutting edge will be ground at the correct angle if the surfaces of the blades are held against these edges of the slots as they are drawn past the grinding wheel.

While I have shown and described preferred embodiments of my invention, it will be apparent that numerous variations and modications thereof may be made without departing from the underlying principles of the invention. I therefore desire, by the following claim, to include withinthe scope of the invention all such variations'and modiiications by which substantially the results of my invention may be obtained through the use of substantially the same or equivalent means.

I claim:

In a Sharpener including a rnotor housing and a motor mounted within the housing having a vertical rotor shaft extending through the top of the housing, the combination of a grinding wheel secured to the rotor shaft above the top of the housing, said grinding wheel having upper and lower bevel surfaces adjacent its periphery, a cylindrical flange secured to and projecting above the top of the housing, a dome shaped guide and guard having a cylindrical lower portion fitting within said flange and enclosing said grinding wheel, atleast two pairs of diametrically oppositely located cooperating interlocking lugs on said flange and on said lower portion of said guide and guard detachably securing said guide and guard to the housing, said interlocking lugs being engaged by rotating said guide and guard relative to said flange through a turn of less than 180, said guide and guard having a pair of slots for guiding knife blades to be ground against the upper and lower bevel surfaces of said grinding wheel, and having a generally diametral slot in its top extending downwardly at an angle of approximately seven degrees from the vertical for receiving and guiding the blade of a pair of scissors, whereby the guide and guard may be mounted on the housing with the knife blade guiding slots in either of at least two different positions relative to the housing.

References Cited in the file of this patent UNITED STATES PATENTS 1,811,069 Webb June 23, 1911 2,077,195 Adams Apr. 13, 1937 2,257,407 Wulff Sept, 30, 1941 2,318,764 Dorris May ll, 1943 2,522,942 Ginen sept. 19, 1950 FOREIGN PATENTS 530,625 Great Britain Dec. 17, 1940 864,572 France Apr. 30, 1941 981,178 France Ian. l0, 1951

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