US2567941A - Device for sharpening cutlery - Google Patents

Description

Sept. 18, 1951 J. F. R. KARLSTROM 2,567,941

DEVICEFOR SHARPENING CUTLERY Filed 001;.

lNVEN OR ORNEY -t he edge of the container.

Patented Sept. 18, 1951 UNITED STATES; PATENT OFFICE DEVICE FOR SHARPENING CUTLERY Johan Fredrik Robert Karlstriim, Stockholm, Sweden, assignor to Aktiebolaget Elektrolux, Stockholm, Sweden, a corporation of the King-.

dom of Sweden Application October 17 1945, Serial No. 622,723 In Sweden October 24, 1944 11 Claims. (Cl. 51-241) This invention relates to domestic appliances, 7

and more particularly to devices for sharpening cutlery, such as knives, for example, and provisions for mounting devices of this type in working position.

In known devices for sharpening cutlery a grinding disc is provided which is intended to V grind opposite faces of the knife edge in succession so that the knives have to be reversed a number of times in order that the knife edge shall be uniformly ground on both faces and that the sharpening shall be completed.

On the other hand other sharpening devices have been pro- .posed for grinding both faces of the edge simultaneously but such devices are in the main too complicated for domestic use.

The main object of this invention is to provide a sharpening device which is suitable for domestic-use and which may be applied to a domestic as to organization and method, together with the.

above and other objects and advantages thereof,

will be better understood by reference to the following description.

According .to the present invention the device 3 for sharpening cutlery, such as knives, includes a- .grinding disc intended to be positively rotated relatively to the knife or the like to be ground and having around its periphery a deep groove which is acute angled at its base and is of fixed dimensions and is intended for the simultaneous grinding of the two faces of the knife edge.

The base of the groove of the grinding disc is formed with a fine clearance, which clearance may be filled with a material, such as paper or the like, which is innocuous to the knife edges The grinding disc may be formed throughout of grinding material or the walls of the groove may be provided with grinding material secured thereto.

In :a, preferred construction the grinding disc J or wheel is connected with a driving roller which is arranged to be rotated by frictional contact with a rotatable member. For example, the driving roller may be pressed against the edge .of a

rotatable container of a kitchen machine of known type. In such a, case a support for the grinding disc and driving roller may comprise a resilient mounting which due to its inherent resiliency retains the'driving roller pressed against The invention will be hereinafter more-fully described with reference to several embodiments thereof which by way of exampl are illustrated in the accompanying drawing, in which:

Fig. 1 shows in side elevation the upper portion of a food mixing or kitchen machine having a sharpening device embodying the invention mounted thereon; v

Fig. 2 shows in plan view the same machine and sharpening device;

Fig. 3 shows the device in plan view on an enlarged scale with the. grinding wheel and the driving roller in section;

Fig. 4 shows a detail of the mounting of the stirrup in the frame of the kitchen machine;

Fig. 5 shows in front elevation the grinding wheel, with one half removed; .and

Fig. 6 shows another embodiment of the grinding wheel in section,also with one half removed.

Referring to Figs. 1. and 2, a rotatable container of aso-c-alled kitchen machine. of known type is designated by Ill. The machine frame carries a swingable arm II which is preferably moved into an inoperative position during grinding by being swung prior to grinding into the position shown in Figs. 1 and 2. I

The grinding member of the sharpening device comprises a grinding wheel l2 and a driving roller 13 which are mounted for rotation on a support M. The grinding wheel l2 consists of two halves or discs l'5, I6, which are held together by screw threads 11. The driving roller l3, which is preferably made of rubber, may also be secured by threads l-8 to a boss 19 of the disc [5 but, if desired, it may be fastened in any other way, for instance by being vulcanized thereon. Since the diameter of the grinding wheel is larger than lying in planes extending. at right angles to each other. One arm 20 formsajournal vor-spindle rotatably supporting. the grinding member and the other arm 2| is utilized to mount th bracket or the stirrup on the machine frame. The grinding member is held in position on the journal 20 by spring- rings 22 and 23. The grinding member cannot be released from the journal until the disc It has been unscrewed from the disc [5, thus making the spring-ring 2.3 accessible.

The arm 2| of the bracket or stirrup is enveloped in a rubber sleeve member 24 which positions the stirrup securely in a corresponding aperture 25 in the machine frame. In the kitchen machine shown in Figs. 1 and 2 an already existing aperture is utilized for this purpose, the aperture becoming available by removing a scraping member therefrom when th grinding device is to be used. When the arm 2| with the rubber sleeve member 24 thereon has been forced into the aperture 25 with .the bracket or stirrup in the position shown in Figs. 1 and 2, the arm 2 is held in position due to the rubber sleeve member 24 being compressed between the arm and the rim of the aperture and pressing resiliently against both elements. The driving roller I3 mounted on the other end of the stirrup is thus pressed against the container edge. On account of the elasticity of the sleeve member 24, the supportis able to pivot slightly about the arm 2? even when the container edge may be slightly non-circular in shape. This mounting, however, provides sufficient friction to prevent the stirrup from becoming loosened from its position other than when the operator intentionally releases it manually. The sleeve member 24 may be suitabl connected to the arm 2|, as by vulcanization thereto, rorexample.

If desired, the sleeve member 24 ma also form a bearing for the arm 2|, in which case it desirably may be formed of metal, synthetic resin or about the arm '2' I.

The inherent resilient mounting for the bracket or support I4 may, if desired, be replaced by a spring controlled pivoting arrangement between the arm .21 and the main portion of the stirrup.

in the embodiment shown in Fig. 6, the two discs |5 and I6 of the grinding wheel are constructed with inlaid grinding material 21 of Car- 'borundum or similar material. In the embodiment shown in Fig. 3, however, the grinding material consists of two annular-sha ed pieces 28 of sandpaper or emery cloth. The grinding wheel's l5 and It are preferably made of synthetic resin or similar material which in and of itself may serve as a bearing element at 20. Preferably the material is of the self-lubricating type since it cannot be assumed that this bearing will be lubricated.

Due to the fact that the grinding wheel, as shown in Fig. 1, is located externallyof the outer face of the container, any powder-or th like resulting from grinding will not fall into the contamer.

In grinding a knife or the like it is held b the handle and the edge of the knife blade is moved down into the acute angled groove 29 which extends about the rotating rinding wheel and is so formed that the edge of the knife is then ground on its two faces. Th extreme edge is protected by the grinding material being covered at the base'o'f the groove by rings 30 of paper or similar material.

In view of the foregoing it will now be understood an improved kitchen utility appliance has been provided comprising a base having a driving member for rotating an upright vessel In about a vertical axis. The bracket in having spaced apart ends 20 and 2| is disposed so that the driven roller l3 and rotatable element l5 connected thereto are carried by the end portion 20. The end portion 2| is supported at a region outside the vessel ID by structure associated with the base of the kitchen appliance, the bracket l4 being movable about such region at the vicinity of the sleeve member 24.

When the driven roller I3 is moved into frictional'engagement with the vessel III while the latter is rotating, rotating movement is imparted to the rotatable element l5 about an axis at an angle with respect to the vertical axis of rotation of the vessel I'll. As best seen in Fig. 2, the driven roller f3 is adapted to be moved into frictional engagement with an exterior surface of the vessel If} at the top open edge thereof to impart rotating movement to the element |5 connected to the roller.

In the embodiment of the invention shown and described above the element f5 forms a knife sharpening accessory comprising grinding disc structure which provides an annular groove having opposing faces containing abrasive material. The roller 3 and disc I5 are rotatably carried by the arm 20 which is substantially perpendicular to the arm 2"| The resilient sleeve member 24 is disposed about the arm 2| which is adaptedto fit snugly in the recess of a part serving as a support. In this way a resilient mounting is provided for the bracket l4 so that, when the knife is pressed downwardly in the groove with the edge thereof extending horizontally, the frictional engagement between the vessel or driving memher It! and roller I3 is increased. Further, the sleeve member 24 of elongated form is of such size and so positioned that the inner contact surface thereof with the arm 2| is longer than the outer contact surface thereof with the wall of the recess.

The disc structure I5 comprises a plurality of parts which provide a relatively deep groove. The opposing faces of the groove contain abrasive material and form an acute angle of such size that, when a knife or other piece of cutlery is positioned with the knife edge directed toward the bottom of the groove and such edge in its lengthwise direction is closely adjacent to or in a plane substantialy normal to the axis of rotation and at the apex of the groove, both sides of the knife edge are conveniently adapted tobe subjected to abrasive action by the material at the opposing faces to effect sharpening of the knife edge. As best seen in Fig. 6, the separating member 30 prevents the opposing faces from being brought into abutting relation and keeps the abrasive material at such faces from coming into intimate contact at the apex of the groove.

While specific embodiments of the invention have been shown and described, it is to be understood thatthis has been done for the purpose of illustration only and that the scope of the invention is not to be limited thereby but is to be determined by the appended claims when interpreted as broadly as the prior art will permit What is claimed is:

1. A device for sharpening cutlery, such as knives, for example, comprising a rotatable driving member, a driven roller which is adapted to frictionally cooperate with the driving member, grinding disc structure connected to the driven roller for rotation about its axis, said structure including a plurality of parts constructed to provide a relatively deep groove about the periphery thereof, the opposing faces of the groov containing abrasive material and forming an acute angle of such size that, when a knife or other "piece'of cutlery is inserted therebetween with the knifeedge directed toward 'the-.bottom;of the g'ro'ove-and such edge in its lengthwise direction isclosely adjacent to or in a plane substantially normal to said axis. at the apex-of the groove, both-sides of the knife edge are. conveniently adapted to be subjected to abrasive actionby the material at the opposing s harpening'of the knife edge. 'aseparating membe r for said parts which is formed and arranged to prevent the opposing faces from being brought into abutting relation and keep the abrasive material at such faces from coming into intimate contact at the apex of the groove, an element upon which the roller is rotatably mounted, and means for resiliently mounting the element so that, when a knife is pressed downwardly in the groove with the edge thereof extending horizontally, the frictional engagement between the driving member and the roller is increased.

2. A device as set forth in claim 1 in which the rotatable driving member comprises an upright open vessel and the driven roller is adapted to frictionally engage the upper edge of the vessel, and said means for resiliently mounting the element being so constructed and arranged that, when a knife is pressed downwardly in the groove with the edge thereof extending horizontally, the frictional engagement between the vessel and the roller is increased, the roller having its axis of rotation substantially perpendicular to a plane bisecting the groove and passing through the apex thereof.

3. A device as set forth in claim 1 in which said element comprises a bracket having two spaced apart arms disposed in planes substantially perpendicular to one another, the roller and disc structure being rotatably carried by one of the arms, and means for resiliently mounting the other arm so that, when a knife is pressed downwardly in the groove with the edge thereof extending horizontally, the frictional engagement between the driving member and the roller is increased.

4. A device for sharpening cutlery, such as a knife, for example, comprising a rotatable driving member, a driven roller which is adapted to frictionally cooperate with the driving member, grinding disc structure connected to the driven roller constructed to provide an annular groove having opposing faces containing abrasive material, an element upon which the roller is rotatably mounted, and means for resiliently mounting the element so that, when a knife is pressed downwardly in the groove with the edge thereof extending horizontally, the frictional engagement between the driving member and the roller is increased.

5. A device as set forth in claim 4 in which the rotatable driving member comprises .an upright open vessel and the driven roller is adapted to frictionally engage the upper edge of the vessel, and said means for resiliently mounting the element being so constructed and arranged that,

when a knife is pressed downwardly in the groove with the edge thereof extending horizontally, the frictional engagement between the vessel and the roller is increased, the roller having its axis of rotation substantially perpendicular to a plane bisecting the groove and passing through the apex thereof.

6. A device as set forth in claim 4 in which said element comprises a bracket having two tially perpendicular to one another; the roller faces to effect Q6 'anddisc structure being rotatablycarried by one of the arms,'and meansforresiliently mounting the other arm so that, when a knife is pressed downwardly'in the groove with the edge thereof extending horizontally, the frictional engagement between the driving member andtherroller is increased.

'7. A device for sharpening cutlery, such as a knife, for example, comprising a support, a rotatable driving member carried by the support, a driven roller which is adapted to frictionally cooperate with the driving member, grinding disc structure connected to the driven roller constructed to provide an annular groove having opposing faces containing abrasive material, a bracket having two spaced apart arms disposed in planes substantially perpendicular to one an other, the roller and disc structure being rotatably carried by one of the arms, a part mounted on said support which is formed with a recess, and means including a sleeve member disposed about the other arm which is adapted to fit snugly in the recess for resiliently mounting the bracket so that, when a knife is pressed downwardly in the groove with the edge thereof extending horizontally, the frictional engagement between said driving member and said roller is increased, the sleeve member being elongated and having a longer contact surface with the other arm than with the wall of the recess.

8. A device for sharpening cutlery, such as a knife, for example, comprising a supporting base, a rotatable driving member carried by the base, a driven roller which is adapted to frictionally cooperate with the driving member, grinding disc structure connected to the driven roller constructed to provide an annular groove having opposing faces containing abrasive material, a bracket having two spaced apart arms disposed in planes substantially perpendicular to one another, the roller and disc structure being rotatably carried by one of the arms, a part mounted on the base which is formed with a recess, and means including a sleeve member disposed about the other arm which is adapted to fit snugly in the recess for resiliently mounting the bracket so that, when a knife is pressed downwardly in the groove with the edge thereof extending horizontally, the frictional engagement between the driving member and the roller is increased.

9. A device as set forth in claim 8 in which the sleeve member is formed of material possessing sufficient resiliency to enable the roller to be brought into good frictional engagement with the driving member.

10. A kitchen utility appliance comprising a base, a driving member carried by the base comprising an upright vessel rotatable about a vertical axis, a driven roller which is adapted to frictionally cooperate with the vessel, a rotatable element connected to the driven roller, a bracket having spaced apart end portions, the roller and element being rotatably carried by one of the end portions, and means associated with said base for supporting the other end portion of the bracket at a region outside the vessel and about which region said bracket is movable, said bracket and supporting means being so constructed and arranged that, when the driven roller is moved into frictional engagement with the vessel while the latter is rotating, rotating movement is imparted to the rotatable element about an axis at an angle with respect to the vertical axis of rotation of the vessel.

mama

n. A kitchen utility appliance as set mm in mm m m which said bracket and. supporting means are so constructed and arranged that the tmven' roller is adapted to: be mnved into trict'ion'a'lz engagement with an exterior surface of 5 the vessel in i mpartrotating movement. to-- the element cem'rected tq the when a FREDRIK ROBERT KARLSTROM.

REFERENCES CITED UNITED STATES PATENTS Number Name Date Dreadon Jan. 4,1810 George et a1. Nov; 19-, 1912 Menyhert; et a1 Mar. 23,1914 Cornell June 1', 1920 Luebben Msty 9, 1922 Binol'er Feb. 20,. I923 Luebben Oct. 20, L925 Gunning May 3-1, 192 Baker Nov. 1, 192-! McLaughlin June: 26, 1928

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