US2841931A

US2841931A - Knife sharpener

Info

Publication number: US2841931A
Application number: US662943A
Authority: US
Inventors: Glen H Holzhausen; William W Haefliger
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-05-31
Filing date: 1957-05-31
Publication date: 1958-07-08
Anticipated expiration: 1975-07-08

Description

y 1953 G. H. HOLZHAUSEN ET AL 2,841,931

KNIFE SHARPENER Filed May 31, 1957 GLEN H. HOLZHAUSEN WILLIAM W. HAEFLIGER INVENTOR. M44 44 MW BY United States Patent KNIFE SHARPENER Glen H. Holzhausen, Palos Verdes, and William W. Haefliger, Pasadena, Calif.

Application May 31, 1957, Serial No. 662,943

8 Claims. (Cl. 51-241) This invention relates to sharpening devices, and more particularly to knife sharpening devices which may be attached to and driven by electrical appliances of the home electric mixer type.

This application is a continuation-in-part of application, Serial No. 347,246, filed April 7, 1953, now abandoned.

It is an object of the invention to provide a novel sharpening device incorporating means for coupling the sharpening device in operative engagement with a variable speed home electric mixer, so that an abrasive element carried by the sharpening device may be rotated at its most efllcient sharpening speed with the spin axis of the rotating abrasive element disposed vertically, so that a knife blade may be sharpened by moving it horizontally into engagement with the abrasive element on opposite sides of the shaft.

It is another object of the invention to provide a sharpening device having a novel rotatable housing with engagement means attached thereto for limiting rotation of the housing, so that a knife blade may be guided by the housing into engagement with a rotating abrasive element enclosed by the housing.

\ It is a further object of the invention to provide a novel knife sharpening device including separate rotatable housing members protecting and enclosing a rotating abrasive element, the housing members being spaced apart to provide an annular groove for the insertion of a knife blade to be sharpened against the abrasive element.

Other objects and advantages will become apparent from a consideration of the following description and the appended claims in conjunction with the accompanying drawings wherein:

Figure 1 is a sectional view of one form of sharpening device of the present invention;

Figure 2 is a plan view of the end of the shaft illustrated in Fig. 1, and taken along line 2-2 thereof;

Figure 3 is an elevational view of the sharpening device illustrated in Fig. l, and taken along line 33 thereof;

Figure 4 is a sectional view of another form of the sharpening device of the present invention;

Figure 5 is a sectional view of another form of the sharpening device of the present invention; and

Figure 6 is a sectional view of still another form of the sharpening device.

Referring now to Fig. 1, there is therein illustrated one form of the novel sharpening unit. The knife sharpener includes an elongated circular shaft 11 which carries an abrasive means such as a wheel or disc 12 mounted thereon. The abrasive wheel is centrally apertured to accommodate the portion 13 of the shaft, and washers 14 and 15 are positioned on either side of the abrasive wheel. The lower end portion of the shaft is threaded, and a nut 16 is tightened against washer 15, forcing the abrasive wheel and washer 14 upwardly so that washer 14 engages shoulder 17 of the stepped portion 18 of the shaft, with the result that the washers and abrasive wheel are rigidly and frictionally gripped between the nut and 2,841,931 Patented July 8,1958

the stepped portion of the shaft. At the same time, the upper surface 19 and lower surf-ace 20 of the abrasive wheel are aligned by the washers 14 and in planes which lie perpendicular to the axis of the shaft. The abrasive disc itself is comprised of an abrasive material dispersed throughout a binder, such as is commonly used in grinding wheels used in grinding metallic objects. The abrasive wheel includes an annular beveled portion 21 which slopes upwardly and outwardly from the lower surface of the wheel at a small angle to intersect the cylindrical outer surface 22 of the wheel.

A housing 25 enclosing a portion of the abrasive element is rotatably mounted about the shaft 11 by means of a cylindrical bearing 26 which is carried by the stepped portion 18 of the shaft. The bearing may consist of bronze or oilite, or any suitable bearing material. A cylindrical portion 27 of the housing is pressed on the outer surface of the bearing so as to be rigidly mounted thereon to support the remaining portion of the housing 25. Housing 25 includes a wall portion 28 extending outwardly from the shaft above the upper portion 19 of the abrasive element, and a cylindrical side wall portion 29 joined to the upper portion and extending downwardly therefrom to a point below the lower surface 20 of the abrasive element. A pair of

slots

30 and 31 are cut or formed in the side wall portion of the housing 25 adjacent the beveled portion 21 of the abrasive wheel, and in alignment therewith. The two slots are formed in portions of the side wall which lie oppositely of the shaft 11. Each slot forms an are which is measured by an angle included between radii extending outwardly from the center of the shaft and having a magnitude lying between 30 and degrees. Slot 31 is better illustrated in Fig. 3 which is a view of the external portion of the sharpener taken at right angles to the section illustrated in Fig. 1. It will be understood that only one slot may be formed in housing 25 if so desired.

Attached to the upper wall portion 28 of the housing 25 is one leg 35 of an arm member 36. The other leg 37 of the arm member extends upwardly from housing 25 and is spaced from the shaft 11. Engagement means such as rubber finger 33 is attached to the end of the leg 37 to provide means for engaging stationary external means such as a portion 39 of the arbor of an electric mixer. It will be understood that when the arm member 38 is in engagement with external means such as electric mixer arbor 39, the housing 25 enclosing the abrasive element will be unable to rotate with the shaft 11 and abrasive wheel 12, since the arm member 36 will resist rotation of the housing. Since the housing 25 and

slots

30 and 31 carried thereby cannot be rotated beyond a certain point when arm 37 is in engagement with external means, a knife blade may be inserted in one of the slots and guided therein to engage the beveled portion 21 of the abrasive wheel. The blade may then be drawn back and forth within the slot as the abrasive wheel is rotated, causing the blade to be sharpened against the beveled portion of the wheel. Should it be desired to sharpen the opposite side of the blade, it may be inserted in the opposite slot to bring the opposite side of the blade into contact with the beveled portion of the rotating abrasive wheel, and the sharpening action repeated. It will be particularly noted that the provision of the oppositely disposed slots enables both sides of the blade to be sharpened without reversing the position of the knife handle with respect to the knife blade; in other words, the blade need only be turned over to sharpen one or the other side thereof, as described above. It will also be noted that the shaft 11 projects downwardly from the mixer arbor 39, with the result that the spin axis of the rotary abrasive element 12 is suspended vertically. It is by virtue of this disposition of elements that the blade to be sharp ened may be conveniently moved horizontally into engagement with the beveled portion 21 of the abrasive wheel, on opposite sides of the shaft, so as to sharpen both sides of the blade.

The portion of the shaft 11 projecting upwardly from the housing 25 has formed thereon attachment means for engagement with retaining means carried by an electric appliance such as an electric mixer of the home type. Such mixers are well known in the art, and for the purposes of the present invention, it will be understood that the attachment means formed on shaft 11 is of such form as will permit the shaft to be attachable to at least one and preferably two or more of the common beater retaining devices carried by various mixers of the type referred to. By way of example, the attachment means carried by the shaft illustrated in Fig. 1 includes a pair of

slots

43 and 44 formed in the upper end portion 46 of the shaft, the slots being disposed at right angles and formed inwardly from the end of the shaft to a depth which approximates half the diameter of the shaft. In this way, four projecting members or

lugs

47, 48, 49, and d are formed at the end of the shaft. A pair of acuate lugs or ears 51 and 52 are also formed on opposite sides of a portion of the shaft located between the end portion 46 of the shaft and the housing 25. in addition, the shaft includes a collar 55' extending along the shaft between the lugs 51 and 52 and the housing 25. Collar includes an annular groove or recess 56 which carries a C-shaped wire spring 57 which is adapted to snap into beater retaining means carried by an electric mixer.

It is to be noted that the upwardly projecting leg 37 of the arm member 36 may be spaced from Shanta a sufficient distance to permit the finger 38 to be insertiblc in a bore in an electric mixer arbor adapted to receive a heater shaft. Thus when the upper end of shaft 11 is inserted in one bore of a mixer, the finger will occupy an adjacent bore so as to be engaged thereby and to enable the arm 36 to resist rotation of the housing 25 when shaft 11 is rotated.

Another form of the present invention is illustrated in Fig. 4. An abrasive wheel or disc 69 is carried by the shaft portion 61 between washers 62 and 63, and a nut 64 is tightened on the threaded lower end portion 65 of the shaft to compress the Washers, the abrasive wheel, and the housing 66 carried by the wheel between the stepped portion 67 of the shaft and the nut. The abrasive wheel has an annular beveled portion 68 facing upwardly, and the under surface 69 of the wheel is protected by the thin housing member 66 which extends outwardly from the shaft 61 toward the outer portion of the wheel, and then upwardly to enclose and protect the side surface 73 thereof. The housing 66 frictionally engages the lower surface 69 and side surface 76 of the abrasive wheel to rotate therewith and protect the wheel during a knife sharpening operation.

A cylindrical bearing 72 such as hearing 26 in Fig. l is fitted over the stepped portion 67 of the shaft so as to be rotatable thereon, and the cylindrical portion 73 of a housing member 74 is pressed over the outer surface of the bearing 72 so as to be rigidly mounted thereon. The housing member 74 comprises a plate which extends outwardly from the cylindrical portion 73 and is spaced closely adjacent the annular beveled portion 68 of the abrasive wheel or disc, so that an annular wedge shaped groove 75 is formed between the outer portion 76 of the plate and the beveled surface 63 of the abrasive wheel. An arm member 78 such as the arm member 36 in Fig. 1 is joined to the upper surface of the plate 74, and a rubber finger 79 is fitted on the upwardly projecting leg 80 of the arm 78.

The upper portion 82 of the shaft carries a rigid cup shaped member 83 immediately above the bearing 72. Member 83 comprises a component of the engagement 4 means carried by the upper portion of the shaft, and also serves to limit upward travel of the bearing 72 and housing member 74. The engagement means also includes a pair of

ears

84 and 85 similar to ears 51 and 52 carried by shaft 11 in Fig. l, and an annular recess 86 is formed at the extreme upper end portion 37 of the shaft.

When the upper portion 82 of the shaft is inserted in the bore of an electric mixer which normally carries a beater, the engagement means described above will connect the shaft in driving or rotating engagement with the power source, so that the shaft and abrasive wheel may be rotated. The upwardly projecting arm will at the same .time serve to prevent rotation of the housing member 74 and thereby prevent dulling of a knife blade against the under surface $9 of the outer portion 76 of the housing member 74, which would otherwise be rotating along with the shaft. The knife blade may be moved into engagement with the beveled surface 63 of the abrasive Wheel and moved longitudinally in the direction of the blade to accomplish sharpening thereof. Should it be desired to sharpen the opposite side of the blade, it need only be turned over and inserted in the groove 75 on the opposite side of the shaft, and the sharpening procedure repeated. 1

The modification of the present invention illustrated in Fig. 5 includes an abrasive wheel 90 carried by shaft portion 91 between washer 92 and cylindrical bearing 93. A nut 94 is tightened on the threaded lower end portion 95 of the shaft to compress the bearing, the abrasive wheel, the housing member 96 carried by the wheel, and the washer in frictional engagement between the nut 94 and the shoulder 97 formed on stepped shaft portion 98. The abrasive wheel has an annular beveled portion 100 facing downwardly, and the upper surface 101 of the wheel is protected by the thin housing 96 which extends outwardly from the shaft 91 toward the side portion 102 of the wheel, and then downwardly to enclose and protect the side portion. The housing 96 frictionally engages the upper and side surfaces of the wheel to 1'0- tate therewith and protect the wheel during its rotation.

The bearing 93 has a flared portion 105 at its lower end, which serves as a lower limit or stop member for the cylindrical portion 106 of housing member 107. Cylindrical portion 106 is freely rotatable about the bearing 93. Housing member 107 comprises a plate which is spaced closely adjacent the annular beveled portion 100 of the abrasive wheel 90 so that an annular wedge shaped groove 108 is formed between the upper surface 109 of the outer portion 110 of the plate and the beveled surface 100 of the wheel. A circular friction member such as rubber ring 111 is joined to the outer extremity of the plate member 107 to serve as a combination braking means and guide for a knife blade when the blade is inserted in the groove 108. The rotation of the bearing 93 on shaft 91 will cause the cylindrical portion 106 of the plate to rotate by means of friction, and the plate 107 and ring 111 will necessarily rotate also. However, when a knife blade is inserted in groove 108, the flat of the blade may be brought into frictional contact with the rotating rubber ring 111 to brake its rotation. The blade may then be kept in engagement with both the ring 111 and the upper surface 109 of the plate member 107 as the blade is moved longitudinally during sharpening in the direction of its axis, and the plate 107 will serve as a convenient reaction member or backer therefor. As the blade is moved longitudinally, the plate and ring will of course slowly rotate since they will be in continuous engagement with the moving flat of the blade. Engagement means permitting attachment of the shaft 98 to an electrical appliance such as an electric mixer are also formed on shaft 98, and comprise elements similar to those illustrated in Fig. 4.

A further modification of the invention is illustrated in Fig. 6. Two thin abrasive discs and 121 are carried in face to face engagement on shaft 122 between supporting plates or housing members 123 and 124. A nut 125.is tightened on the threaded end of shaft 122 to compress the abrasive discs and housing members between the nut and the shoulder 126 formed on shaft 122 by collar 127. The housing members 123 and 124 rotate with the abrasive discs and serve to protect the flat outer surfaces of the abrasive discs and also to align the discs in planes lying perpendicular to the axis of the shaft 122. The upper disc 120 has an annular beveled surface 128 facing downwardly toward a similar beveled surface 129 on the lower disc, facing upwardly. Extending between the two housing members 123 and 124 and between the two

beveled surfaces

128 and 129 is an annular wedge shaped groove 130 within which a knife blade is adapted to be inserted during a knife sharpening operation. When the blade is brought into contact with the rotating

abrasive surfaces

128 and 129 and moved longitudinally, both sides of the blade will be sharpened. Should the beveled surfaces on the abrasive discs wear out, the sharpener components may be readily disassembled so that the abrasive discs may be replaced. Engagement means permitting attachment of the upper portion 131 of the shaft to an electrical appliance such as an electric mixer are formed on portion 131 of the shaft and comprise elements similar to those illustrated in Fig. 1. These elements comprise a C-shaped spring ring 57 carried by annular recess 135 in collar 127, and a slot 44 formed in the upper end of the shaft. The upper portion of the shaft is received in core 136 of spindle or socket 137 driven in rotation by electric motor driven worm gear 138 meshing with spur gear 139 mounted on the spindle. A driving pin 140 extending across bore 136 in the spindle is engaged by the slot 44 when the shaft is inserted in bore 136 and serves to connect the shaft to the spindle for rotation. The spindle is itself mounted in casting 141.

The shaft is held in inserted position in bore 136 by expansion of the snap ring spring 57 into annular recess 142 in spindle bore 136. In this position, the snap ring engages both the recess 142 and the annular recess 135 in the shaft collar 127.

Parts 137 through 141 and 39, are all part of the mixer arbor section which normally overhangs. a mixing bowl during mixer operation, with heaters attached.

We claim:

1. For combination with a home electric mixer having an arbor section adapted to rotate a mixer beater stem, an assembly comprising a rod sized for endwise upward reception in an arbor socket and rotation by the arbor section with the rod projecting outwardly and downwardly from said socket away from the arbor section, an abrasive disc carried by the rod and rotatable coaxially therewith in spaced relation to the arbor section for sharpening a knife blade presented to said disc, means including a cylindrical housing mounted coaxially on the rod to rotate freely beneath said arbor section and independently of the rod about said abrasive disc in at least partially protecting relation therewith, said rod projecting upwardly away from the housing, and a handle carried by the housing extending away from said rod above the bottom level of the housing and then projecting upwardly to engage a part of the arbor section spaced from the rod when the rod is rotating for resisting rotation of said housing therewith.

2. The invention as defined in claim 1 in which said housing contains a slot below the level of said handle and through which said knife blade is insertible for presentation to said abrasive means.

3. The invention as defined in claim 2 including a. sleeve bearing on the rod spaced inwardly from said handle and mounting said housing to rotate freely about the rod in spaced relation to said abrasive disc.

4. The invention as defined in claim 3 including a lug on the rod above the housing adapted to interfit with and be rotated by an arbor section lug when the rod lug is received into said socket.

5. In combination with a home electric mixer having an arbor section adapted to rotate a mixer beater stem, an assembly comprising a rod removably received endwise into an arbor socket to be rotated by the arbor section with the rod projecting outwardly from said socket away from said arbor section, an abrasive disc carried by the rod and rotatable coaxially therewith in spaced relation to the arbor section for sharpening a knife blade presented to said disc, means including a cylindrical housing mounted coaxially on the rod to rotate freely beneath said arbor section and independently .of the rod about said abrasive disc in at least partially protecting relation therewith, said rod projecting upwardly away from the housing, and a handle carried by the housing extending away from said rod above the bottom level of the housing and then projecting upwardly in engagement with a part of the arbor section spaced from the rod when the rod is rotating for resisting rotation of said housing therewith.

6. The invention as defined in claim 5, in which said housing contains a slot below the level of said handle and through which said knife blade is insertible for presentation to said abrasive means.

7. The invention as defined in claim 6 in which said handle is relatively small and projects alongside the arbor section shell.

8. In combination with a home electric mixer having an arbor section adapted to rotate a mixer beater stem, an assembly comprising a rod removably received endwise into an arbor socket to be rotated by the arbor section with the rod projecting outwardly from said socket away from said arbor section, an abrasive disc carried by the rod and rotatable coaxially therewith in spaced relation to the arbor section for sharpening a knife blade presented to said disc, a cylindrical housing at least partially protecting said abrasive means, and means mounting said housing coaxially and exclusively on the rod to rotate relative thereto so that the rod may rotate independently of the housing while the housing is prevented from rotating relative to said arbor section, said rod. projecting upwardly away from the housing.

References Cited in the file of this patent UNITED STATES PATENTS 822,070 McLeran May 29, 1906 1,415,375 Lueben May 9, 1922 2,114,106 Geveke Apr. 12, 1938 2,684,561 Lindgren July 27, 1954 2,716,846 Gerth Sept. 6, 1955 2,722,783 ORussa Nov. 8, 1955 2,735,247 Holzhausen Feb. 21, 1956