US2897637A - Electric knife sharpener - Google Patents

Description

1959 w. H. BODLE 2,897,637

ELECTRIC KNIFE SHARPENER Filed Jan. 15, 1958 2 Sheets-Sheet 1 z E! (9/1 I 11 i 4 5 iii i M722 1 24 7152121? E ,HODLE,

INVENTOR.

Aug. 4, 1959 i w. H. BODLE 2,397,537

ELECTRIC KNIFE SHARPENER Filed Jan. '15, 1958 7 2 Sheets-Sheet 2 .haurse E 80045,

' INVENTOR.

ELECTRKC KNIFE SHARPENER Application January 15, 1958, Serial No. 709,146

4 Claims. (Cl. 51--128) This invention relates to improved electrically operated knife sharpening devices, typically usable as kitchen appliances in the home, and which may if desired be utilized m me type of combined knife sharpening and can opening device disclosed in my copending application Serial Number 626,114, filed December 4, 1956, on Can Opening and Knife Sharpening Device. The present application is a continuation-in-part of that prior application.

A device embodying the invention includes an electric motor, and a grinding wheel driven by the motor at a speed to properly sharpen a knife blade which is placed in contact with the wheel. The motor and at least a portion of the grinding wheel are contained within a housing which is so constructed as to allow proper sharpening contact of the wheel with the knife blade.

The general object of the present invention is to provide an improved sharpener of this type which is especially designed to allow very quick and easy removal and replacement of the grinding wheel assembly after it has become worn. In prior home-use sharpeners of this general type, the method of mounting of the grinding wheel has generally been such as to require returning of the entire device to the factory or service station when it becomes necessary to remove and replace the grinding-wheel. In a device embodying the present invention, on the other hand, the grinding wheel and its shaft may be very easily removed, and a new wheel substituted, in the home and without special tools or equipment of any type.

To achieve this ease of replacement, I provide the housing of the device with a cover section which is removable to allow access to the grinding wheel, and I so design the mounting for the grinding wheel as to cause the cover section of the housing to itself lock the grinding wheel in its active grinding position, when the cover is in place on the housing. As a result, the grinding wheel may be very easily freed for removal from the housing merely by detachment of the cover from the housing. Preferably, the cover performs this function by engaging and locking a hearing or bushing in place, which bearing acts to journal the grinding wheel for rotation about a predetermined axis. This bushing may journal one end of a shaft which carries the grinding wheel, with a second bushing being provided for journalling the opposite end. Also, that shaft may carry a gear which is engageable with an associated driving gear when the shaft is in its active position, to thus transmit driving power from the motor to the grinding wheel.

The cover section preferably is apertured to pass a knife blade into contact with the grinding wheel, and also desirably carries guide means for holding the blade in an optimum position during the sharpening operation. Certain particular features of the invention have to do with a preferred construction for the cover, according to which the cover may have two converging slots for receiving and guiding a knife blade, with these slots being formed in unique manner by two separately formed parts which form together a composite cover assembly.

The above and other features and objects of the present invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawings in which:

Fig. 1 is a perspective view of a combination can opener and knife sharpener device constructed in accordance with the invention;

Fig. 2 is a front view, partially broken away, of the Fig. 1 device, and taken on line 22 of Fig. 1;

Fig. 3 is a fragmentary top plan view of the knife sharpener portion of the device, and taken on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary vertical section taken on line 44 of Fig. 2;

Figure 5 is an enlarged fragmentary vertical section taken on line 55 of Fig. 2;

Fig. 6 is an enlarged fragmentary vertical section taken on line 66 of Fig. 2.

Fig. 7 is an exploded perspective View of the grinding wheel and its associated gears and other parts;

Fig. 8 is an exploded perspective view of the cover assembly which encloses the upper side of the knife sharpening portion of the device;

Fig. 9 is a fragmentary horizontal section taken on line 99 of Fig. 2; and

Fig. 10 is a View representing the manner in which a new grinding wheel assembly is inserted into operative position in the device.

Referring first to Figs. 1 and 2, and particularly to Fig. 1, I have shown at 11) a combined can opening and knife sharpening device, whose knife sharpening portion is constructed in accordance with the present invention. This device includes a housing 11, carrying at one of its sides the can opening mechanism generally represented at 12, and containing toward its other side (at its right end as seen in Fig. 2) a rotary grinding wheel 13 which is accessible to a knife through a pair of elongated slots 14 and 15, in order to sharpen the knife. The can opening mechanism 12 and the grinding wheel 13 are both driven by an electric motor 16 contained within housing 11. This motor 16 may be a conventional shaded pole induction motor, whose laminated stator is represented at 17, and Whose field coil is represented at 18. The rotor of motor 16 is carried by and drives a rotary shaft 19 which turns about a horizontal axis represented at 20.

Housing 11 may be formed of several cast metal sections, including a first body section 21, a second section 22 for carrying the can opener mechanism 12, and a removable cover assembly 23 which extends over and encloses the upper side of grinding wheel 13. This cover assembly 23 may be formed of two cast metal sections 24 and 25 rigidly secured together (see Fig. 9). Housing section 22 closes one side of section 21, and is suitably secured thereto, as by screws 24.

The specific details of the can opening mechanism 12 comprise no part of the present invention, and therefore this mechanism will not be discussed in detail in the present application. A more specific description of the can opening mechanism will be found in my copending application Serial No. 626,114, filed December 4, 1956, on Can Opening and Knife Sharpening Device. For present purposes, it may be stated that the can opening mechanism 12 includes a can advancing wheel 25 driven by motor 16, through a speed reduction gear assembly, and a cutter wheel 26 which is shiftable between can cutting and released positions, and which will function to cut a can lid as the can is turned by wheel 25. Cutter 26 is shifted by swinging movement of a lever 27 between the upright inactive position of Fig. 1, and the full line active position of that figure. At the end of this swinging movement, lever 27 engages and actuates the movable actuating element 28 of a switch 29 which is contained within housing 11, and which acts to close the energising circuit to motor 16 when switch 28 is so actuated. Lever or handle 27 swings about a horizontal axis 29, and is mounted for such swinging movement by reception of a cylindrical projection 30 of handle 29 within a cylindrical bushing or opening 31 formed in housing part 22.

The stator 17 of electric motor 16 is rigidly mounted in fixed position within housing 11, as by a pair of screws 32 which may extend through stator 17 and connect into a pair of rigid mounting posts 33 attached to section 22 of housing 11. Rotor shaft 19 and the carried rotor are mounted for rotation about horizontal axis 20 by means of a pair of bearings 34 and 35 suitably attached to stator 17. Wheel 25 of the can opening mechanism may be driven by motor 16 through any suitable type of drive connection, preferably including a gear train contained within a :gear housing 36 mounted within main housing 11 of the device. The underside of housing section 21 may be'closed by a horizontal plate 37, and the entire housing may be supported on a suitable table or other support surface 38 by means of a number of rubber feet or cushions 39.

Referring now to Figs. 7 and 9, the motor bearing 35 may be a ball bearing assembly rigidly attached to the inner side of a bracket 40 which is in turn rigidly secured to motor stator 17 by means of a pair of screws 41, which pass through a pair of openings 142 in stator 17, and whose ends are screwed into threaded openings 42 in bracket 40. At the opposite side of the stator, screws 41 may have heads 43 serving to secure a second bearing assembly 34 to the stator. The housing bearing assembly 35 may be attached to bracket 40 by means of a pair of ears 45 formed on the bearing housing, and containing openings through which a pair of lugs 46 on bracket 40 project, with these lugs being upset or peened to retain the bearing against bracket 40.

Beyond bearing 35, the motor shaft 19 projects through an opening 47 in bracket 40, and rigidly carries at the outer side of this bracket a gear 48. This gear may be a die cast type of gear, which is rigidly carried by and keyed to the shaft. At a location offset forwardly and downwardly from shaft 19, bracket 40 has a short shaft portion 49 cast integrally with the bracket, and externally cylindrical to rotatably mount thereabout a compound gear 50, which is desirably formed of nylon or other resinous plastic material. The gear 50 is retained against axial displacement from about shaft 49 by means of a screw 51 (see Fig. 2), whose shank threadedly connects into an inner threaded recess in shaft 49, and whose head is large enough to engage the outer side of gear 50 and retain it on the shaft. The gear 50' has a first set of teeth 52 which mesh with the teeth of motor driven gear 48, to be driven thereby, and the gear 50 also has a second increased diameter series of teeth 53 for meshing with and driving the teeth 54 formed on a preferably cast metal part 55 which carries the :grinding wheel 13. The rotary axes 56 and 57 of parts 50 and 55 extend parallel to the horizontal main axis 20 of motor 16 and its driven shaft 19. As seen best in Fig. 6, axis 57 of the part or shaft 55 is offset to the left of and slightly above the main axis 20. The number of teeth on gears 48, 52, 53 and 54 may typically be 14 teeth, 14 teeth, 25 teeth, and teeth respectively, so that the grinding shaft 55 will turn at a speed two and a half times as great as the speed of motor shaft 19.

At its opposite ends, the part 55 has a pair of aligned externally cylindrical bearing surfaces or portions 59 and 60, which are received and rotatably journaled within a pair of essentially tubular bushing sleeves 61 and 62. These bushings 61 and 62 are desirably formed of nylon or other suitable long wearing resinous plastic material, to thus effectively journal the cast metal part 55 with a of wear.

Sleeve 61 is removably receivable 4 within a tubular mounting lug 63 formed integrally with and projecting horizontally from bracket 40. At two diametrically opposite locations, bearing sleeve 61 may have a pair of small projections 64 which are receivable within notches 65 in lug 63, to key part 61 against rotation relative to lug 63. As best seen in Fig. 5, the second nylon bushing 62 is preferably made of noncircular (desirably square) cross section, taken in a vertical plane, and has its lower portion partially received and confined within a correspondingly non-circular recess 66 formed in a portion 67 of housing section 21. More specifically, the recess 66 has a horizontal bottom wall 68 upon which a correspondingly horizontal undersurface of part 62 rests, with the opposite sides of the part 62 being engaged and confined by a pair of vertical walls 69 of recess 66. As will be discussed at a later point, the cover 23 of housing 11 functions to hold the hearing or bushing 62 in fixed position within the housing, when the cover is secured in its position of use.

The grinding wheel 13 is formed of a suitable abrasive material having a rather fine grit size (typically between about 180 and 220 mesh). This grinding wheel 13 is desir-ably annular, and has an inner internally cylindrical opening 70 of a dimension to fit closely about and be carried by a correspondingly cylindrical enlarged diameter portion 71 of shaft member 55. At one end of surface 71, part 55 integrally carries a radially extending annular flange 72 against which the reduced thickness portion 73 of wheel 13 abuts axially. At the opposite side of wheel 13, a retaining ring 74 clamps wheel 13 by peening of an annular flange 75 on part 55 radially outwardly against an inclined annular surface 76 formed along the inner edge of part 74. The wheel 13 may be positively keyed against rotation relative to part 55 by means of a pair of integral lugs 77 formed on flange 72 and projecting into corresponding recesses or notches formed in abrasive wheel 13. The actual grinding faces of wheel 13 take the form of two annular faces 78 and 79, facing in opposite axial directions, and converging axially toward one another as they advance radially outwardly.

At the location of grinding wheel 1-3 and housing cover 23, the section 21 of the housing is of essentially rectangular configuration, with the cover assembly 23 forming in efiect an upper continuation of this rectangular shape. More specifically, housing section 21 has a vertical end wall 80 extending transversely of axis 20 and merging with a pair of parallel vertical front and rear walls 81 and 82 (see Fig. 4). At the location of cover assembly 23, these three walls 80, 81 and 82 terminate upwardly in edges 83 which lie in a common horizontal plane, and which engage and support corresponding lower edges 84 of the main cover section 24. Section 24 has a vertical end wall 85, two vertical front and rear walls 86 and 87, and a top horizontal wall 88. The walls 85, 86 and 87 are aligned vertically with, and form upper continuations of the previously mentioned Walls 80, 81 and 82 of housing section 21. Projecting downwardly from each of the three vertical walls 85, 86 and 87, part 24 has three integrally formed lugs 89,

which are received at the inner sides of the upper por- -tions of walls 80, 81 and 82, and are removably attachable to those walls by three screws 90 extending through openings in walls 80, 81 and 82 and threadedly engaged within openings 91 and lugs 89. At a side opposite the location of end wall 85, part 24 has an edge 92 lying in a vertical plane and engaged against edges formed along the top, front and rear of part 21, so that the cover forms a continuation of housing section 21 at that location. At their upper edges, walls 85, 86 and 87 may curve inwardly smoothly at 93 to merge with the horizontally extending upper wall 88 of part 24.

The walls 86, 87 and 88 of part 24 are interrupted at the location of section 25, which forms in effect continuations of walls 86, 87 and 88 respectively, but with the previously mentioned knife blade receiving slots 14 and 5 15 being formed between sections 24 and 25 for guiding a knife during a sharpening operation. More specifically, section 25 has a small vertically extending and then horizontally curving front wall portion 94 which is aligned laterally with front wall 86 of part 24, and similarly part 25 has a rear vertical wall 85 aligned laterally with and in the same plane as rear wall 87 of part 24. Across its upper side, part 25 has a top horizontal wall 95 which is aligned horizontally with and forms in effect a continuation of top wall 88 of part 24.

As seen in the plan view of Fig. 3, the slots 14 and 15 converge as they extend from front to rear, with the angle formed between one of these slots and axis 20 being the same as but the reverse of the angle formed between the other slot and that axis. Also, the portions of the slots 14 and 15 which are formed between the vertically extending front walls 86 and 94 of sections 24 and 25, and the vertically extending rear walls 87 and 195 of sections 24 and 25, converge downwardly, so that a blade received within either the slot 14 or the slot 15 is inclined downwardly and inwardly toward grinding wheel 13, as well as being disposed at an angle with respect to its front to rear extent. Section 24 has two inclined and angularly extending walls 96 and 97 formed within the housing beneath the level of the upper walls 88 and 96, and extending all of the way from front wall 86 to rear wall 87. These walls 96 and 97 are disposed at an angle corresponding to the angle of the blade received within and guided by slots 14 and 15 respectively, to thus laterally support the blade as it is drawn forwardly through the slots while engaging the grinding wheel 13. The peripheries of inclined planar walls 96 and 97 form first sides of the knife guiding slots 14 and 15, with the opposite sides of those slots being formed by opposed edges of part 25, which edges extend parallel to and in spaced relation to the edges of surfaces 96 and 97. Thus, the various edges forming slot 14, and the associated guide surface 96, are positioned to receive and guide a planar knife blade within slot 14 and against surface 96, and the same is true of slot 15 and the associated surface 97. Walls 96 and 97 may be interrupted toward their forward ends at 98, sufficiently to allow for reception of the wheel 13 between these walls 96 and 97 without any interference being offered by the walls. At the bottom of the recess formed in part 24 by the downwardly extending walls 96 and 97, the part 24 has a horizontal bottom wall 99, which is spaced a short distance above edges 83 and 84, and also above axis 20 of wheel 13, and which acts to support the engaged knife blade in a horizontally extending position, and to limit the downward movement of the knife blade. At the forward side of wheel 13, there may be provided a short forward continuation 100 of horizontal wall 99, to engage the blade at that location.

As the knife blade 102 received within slot 14 or 15 is pulled forwardly within that slot, the cutting edge 101 of the blade (see Fig. 4) engages one of the two grinding faces 78 or 79 of grinding wheel 13, at the forward side of the grinding wheel, so that the knife may be sharpened on both of its sides by first pulling it forwardly through slot 14, and then pulling it forwardly through slot 15. The grinding wheel 13 turns in a direction such that the forward engaged portion of the grinding wheel is moving upwardly, to thus perform a most effective sharpening operation. Also, as will be apparent, the angularity of annular grinding faces 78 and 79 with respect to the axis of wheel 13 is such as to correspond with the angularity of the knife blade at the point of engagement of the blade with the grinding wheel, so that surface 78 or 79 engages the knife blade across the entire radial extent of face 73 or 79.

In order that the part 25 may form the inner edges of the two converging knife guiding slots 14 and 15, this part 25 has opposite side edges 103 and 104, which converge rearwardly along the top of the housing. and Which converge downwardly at the rear and front side of the housing (but with the edges being spaced farther apart at the rear of the housing than at its front). All portions of edge 103 of course lie in a common inclined plane, and similarly all portions of edge 104 lie in a single plane. Part 25 is mounted in fixed relation to the other cover section 24 in any suitable manner, as by means of a screw 105 extending upwardly through an opening in horizontal bottom wall 99 of part 24, and threadedly connected into a threaded bore 106 in a vertically extending portion 107 of part 25. This attachment may be strengthened by providing a vertical web 103, whose lower edge engages the upper side of wall 99 at 109, and which may be cut away arcuately at its forward edge 110 to avoid contact with wheel 13. Also, lugs 111 formed on the upper surface of wall 99 may be receivable within locating recesses in the underside of Web 108, to assist in locating part 25 relative to part 24.

As previously mentioned, the square bushing 62 which journals the outer end of cutter mounting shaft 55 is locked in its operative position by attachment of the cover assembly 23to the upper side of housing part 21. For this purpose, part 24 of the cover assembly may have a pair of vertically extending and generally parallel webs or walls 112 (see Fig. 5) which may extend vertically and perpendicular to end wall 85, and whose lower extremities contain small essentially right angle recesses 113 adapted to engage and confine and positively position the upper portion of bushing 62. More specifically, each of these notches or recesses has an upper horizontal wall 114 which bears tightly downwardly against the upper horizontal surface of square bushing 62, and each of the webs 112 forms also a small lug 115 projecting downwardly along one side of the bushing 62 in a relation positively holding bushing 62 in a fixed position within the housing when cover assembly 23 is held in its Fig. 2 assembled position by screws 90. The bushing is held against axial movement axially away from shaft part 55 by means of abutting engagement of a transverse vertical end surface 116 on.bushing 62 with a correspondingly vertical and transverse surface formed at the inner side of wall 85 of part 24. Also, bushing 62 may have a similar engagement at its lower edge with housing part 21 at 117.

To now describe the manner of operation of the illustrated device, when it is used as a knife sharpening device, assume first that the actuating handle 27 is in its upwardly projecting broken line position of Fig. 1. From this position, the handle 27 is swung to its full line position of Fig. 1 and into engagement with actuating element 28 of switch 29, to close that switch and thus energize motor 16. As shaft 19 of the motor turns, it turns the carried gear 48, which drives gear 50, and which in turn engages and drives the gear portion 54 of the wheel carrying part 55. This turns grinding wheel 13 at a relatively fast speed, typically 9000 rpm. where motor 16 is a two pole induction motor. The user then can pull the knife blade 102 forwardly through slot 14 and then through slot 15, perhaps several times, so that the opposite sides of the cutting edge of the knife can engage the tapering surfaces 78 and 79 of the grinding wheel (at a proper angle determined by the angularity of the slots and of faces 78 and 79), to thus produce an accurately predetermined type of cutting edge on the blade.

When it is desired to remove and replace the grinding wheel 13, after it has become worn, this may be effected by merely removing cover assembly 23 (comprising parts 24 and 25 rigidly secured together), to thus free the entire grinding unit for easy removal from the housing. More specifically, the screws 90 are removed from the device, and then the cover assembly 23 is free to be easily removed upwardly from the rest of the housing. This exposes the grinding wheel, so that a user may grasp that wheel and lift it upwardly very slightly to pass the vertical surface on wall 80 at 117, following which the 7 grinding wheel 13 and its carrying part 55 may be slipped axially out of its position of engagement with bushing retaining element 63, so that an entirely new grinding assembly may be substituted. The bushings 62 and 61 are removed with this assembly which includes parts 55, 13, and 73, so that the entirely new assembly which is substituted will include parts 55, 13, 73, 61 and 62. After this assembly has been positioned as shown in Fig. 2, the cover assembly 23 may be placed back into its active position, to thus lock bushing 62 and the other parts in their active Fig. 2 positions, and the cover may then be positively retained in that position by screws 90 so that the entire apparatus will then be again ready for use. As the new grinding assembly is slipped into place, it is first placed in the position of Fig. 10, and then is slipped axially into a position in which shaft portion 59 and bushing 61 are properly received within element 63, following which bushing 62 may be slipped downwardly a short distance into its position-of engagement with the vertical wall 117 of part 21, to thus ready the entire apparatus for receipt of the locking cover assembly.

I claim:

1. A knife sharpening device comprising a housing, an electric motor in said housing having a rotatably driven shaft, a second shaft removably mounted in an active position in the housing and driven by said first shaft, a grinding wheel carried by said second shaft for sharpening a knife, said housing including a main section and a removable cover section forming an upper side of the housing at the location of said grinding wheel, fastener means for detachably securing said cover section in a predetermined assembled position relative to said main section of the housing, said cover section being apertured to allow contact of said grinding wheel with a knife to sharpen the knife when the cover section is insaid assembled position, two removable bushings extending about and rotatably journalling said second shaft near its opposite ends respectively and at opposite axial sides of said grinding wheel, a shoulder carried by said main section of the housing and on which a first of said bushings is supported in an active position thereof, a locking shoulder on said cover section adapted to engage downwardly against said first bushing and coact with said first shoulder in confining and locking said first bushing in its active position when the cover is in said assembled position thereof, a boss structure in the housing removably receiving and positioning the second of said bushings,

said second bushing and said second shaft being removable from said boss structure only by axial movement relative thereto in a direction toward the location of said first shoulder, one of said housing sections being constructed to block said axial detachment of said second shaft from the boss structure when said cover section is in its assembled position, said second shaft and said wheel and said two bushings being freed for axial detachment from the boss structure and for complete removal from the housing when said cover section is removed from the main section of the housing, a first gear rotatably mounted in the housing and driven by said motor, and a second gear carried by said second shaft and adapted to move into and out of meshing driven relation with respect to said first gear by movement of the second shaft into and out of active position.

2. A knife sharpening device as recited in claim 1,

in which said first bushing is of essentially rectangular cross section, said main housing section containing an essentially rectangular recess for receiving a portion of said bushing and having said first shoulder as a bottom Wall of the recess, there being two of said locking 'ShOlll-r ders carried by the cover section and formed by two lugs containing essentially right angle recesses receiving and locating two corners respectively of said first bushing.

3. A knife sharpening device as recited in claim 1, in which said first gear is an idler gear mounted in the housing for rotation about an axis parallel to but offset from the axes of said first and second shafts, there being a. third gear carried by said first shaft and driving said idler gear.

4; A knife sharpening device comprising a housing, an electric motor in said housing having a rotatably driven shaft, a second shaft removably mounted in an active position in the housing and driven by said first shaft, a grinding wheel carried by said second shaft for sharpening a knife, said housing including a main section and a removable cover section at the location of said grinding wheel, fastening means for detachably securing said cover section in a predetermined assembled position relative to said main section of the housing, said cover section being apertured to allow contact of said grinding Wheel with a knife to sharpen the knife when the cover section is in said assembled position, a bearing rotatably journalling said second shaft near a first end thereof, locking shoulder means carried by said cover section and adapted by movement of said cover section to said assembled position to clamp said bearing against said main housing section in a predetermined active position and to thereby lock said second shaft in its active grinding position, a boss structure carried by said main housing section carrying means for journalling the second end of said second shaft, said second end being detachable from said boss structure only by axial movement, one of said body sections being constructed to block said axial detachment of the second shaft from the boss structure when said cover section is in its assembled position, said bearing and said second shaft and grinding wheel being freed by said locking shoulder means for detachment from the boss structure and complete removal from the housing when the cover section of the housing is detached from the main section, a first gear in the housing driven by said motor, and a second gear carried by said second shaft and adapted to engage and be driven by said first gear when the shaft is locked in said active position thereof, said second gear being freely movable out of engagement with said first gear upon removal of the second shaft and grinding wheel from the housing.

References Cited in the file of this patent UNITED STATES PATENTS

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