US2751721A

US2751721A - Blade sharpening apparatus

Info

Publication number: US2751721A
Application number: US367596A
Authority: US
Inventors: Richard B Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-07-13
Filing date: 1953-07-13
Publication date: 1956-06-26
Anticipated expiration: 1973-06-26

Description

June 26, 1956 R. B. SMITH BLADE SHARPENING APPARATUS 2 Sheets-Sheet 1 Filed July 15, 1953 Rwamav B. SMIT,

INVENTOR.

ATTORNEYS June 26, 1956 R. B. SMITH BLADE SHARPENING APPARATUS 2 Sheets-Sheet Eiled July 13, 1953 ig RICHARD B. S N\\T-H- 55 INVENTOR.

ATTORNEYS United States Patent BLADE SHARPENING APPARATUS Richard B. Smith, Hickory, N. C.

Application July 13, 1953, Serial No. 367,596

13 Claims. (Cl. 51-428) This invention relates to improvements in blade sharpening or honing devices and, more especially, to a novel means for supporting and guiding a blade as it is manually drawn against the planar end surface of an abrading wheel and wherein a means is provided for attenuating or stretching the molecular structure of the cutting edge of the blade as it is being sharpened or honed.

This application is a continuation in part of my copending application entitled Blade Sharpening Device, Serial Number 228,669, filed May 28, 1951, now Patent No. 2,645,063, dated July 14, 1953.

It is the primary object of this invention to provide an improved blade sharpening or honing apparatus embodying the theory of magnetostriction, as defined in said co-pending application, and wherein said improved apparatus comprises a driven abrading wheel having a circular cavity in one end thereof with means for supporting a permanent magnet so that it is partially loosely disposed in said cavity and wherein an improved blade guiding and positioning means is provided to facilitate manually drawing the blade past the planar edge of the rim of the abrading wheel defined by said circular cavity while maintaining the blade at a predetermined angle relative to the planar surface so that the cutting edge of the blade is uniformly beveled throughout the length of the blade as it is sharpened or honed. The cutting edge of the blade is disposed against or closely adjacent the magnet as the blade is drawn through the improved blade positioning and guiding means and the magnet causes minute molecules of the blade to be attenuated or stretched under the influence of the magnet to also produce an unusually sharp or keen cutting edge.

It is another object of this invention to provide a blade sharpening apparatus comprising an abrasive element in the form of a driven rotatable drum preferably mounted on a vertical axis and having a circular cavity in its upper end which defines a circular abrasive rim. The lower portion of a permanent magnet is encircled by said abrasive rim so that its upper portion projects above the upper surface of the rim of the drum. Mounted closely adjacent the drum is a verticallymovable blade supporting and guiding device comprising a bracket having a flat upper surface upon which a blade guide memher, having flat upper and lower surfaces, is positioned.

Corresponding inner ends of the bracket and the blade guiding member are provided with' coinciding. arcuate recesses therein which are formed substantially concentric with, and are of a slightly greater radius than, the exterior of said drum. The inner end of the blade guiding member is resiliently maintained in engagement With the inner end of the bracket and the outer ends of the bracket and the blade guiding member are provided with downturned arcuate portions thereon whose proximal faces are adjustable in sliding engagement with each other about the point at which the inner end of the. blade guiding member engages the inner end of the bracket, so. that the upper surface. of the blade guiding member may be disposed at any desired angle relative to the upper surface of the rim, means being provided for locking the blade guiding member in the desired adjusted position.

A flat relatively thin pressure applying plate is loosely positioned upon the blade guiding member and its inner edge is also formed with a recess coinciding with the recesses in the bracket and the blade guiding member. Resilient means normally urges the bracket and the parts supported thereby upwardly and normally maintains the upper surface of the bottom blade guiding member above the level of the upper surface of the abrading wheel and, in operation, a blade is inserted between the pressure applying plate and the blade guiding member and manual pressure is then exerted on the pressure applying plate sufiiciently to press the blade downwardly until it engages the upper surface of the abrading wheel, whereupon the blade is then manually drawn past the abrading wheel for sharpening the same.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings in which- Figure 1 is a top plan view of the improved blade sharpening apparatus showing a knife blade in phantom lines, as though being sharpened or honed;

Figure 2 is a side elevation of the improved blade sharpening apparatus;

Figure 3 is an enlarged fragmentary sectional plan view taken substantially along line 3-3 in Figure 2;

Figure 4 is a fragmentary elevation looking along line 4-4 in Figure 2 and showing the carrying handle for the apparatus in raised position;

Figure 5 is an enlarged fragmentary vertical sectional view taken substantially along line 55 in Figure 1, showing the blade guiding and positioning device in raised or inoperative position;

Figure 6 is a view similar to Figure 5, but showing the blade guiding and positioning device as it is manually pressed downwardly into operative position, when in use, and showing a blade in the guiding means in crosssection;

Figure 7 is a fragmentary sectional detail of the blade guiding device taken substantially along line 77 in Figure 4.

Referring more specifically to the drawings, the numeral 10 indicates an electric motor having wires 11 and 12 extending therefrom which are adapted to be connected to a suitable source of electrical energy, not shown. The electric motor 10 is supported in a suitable frame or stand shown in the'form of a cylinder 13 which is preferably open at its lower'end and closed at its upper end by a plate 14, the plate 14 being preferably cast integral with the cylinder 13. The frame or cylinder 13 may rest upon a suitable table or the like while the improved blade sharpening apparatus is in use. The electric motor 10 is suitably secured to the plate 14, as by screws 15.

The motor 16 drives a shaft 16 which projects upwardly through a suitable opening 17 provided in the plate 14 and the upper end of the shaft 16 has a reduced threaded portion 20 thereon on which a circular abrasive member, drum or abrading wheel 21 is fixedly secured by means of a nut 22 and a washer 23. The abrading wheel 21 has a circular cavity 24 in its upper or outer end which defines an annular portion or rim 25 on the upper end portion of the abrading wheel 21. The annular portion or rim 25 of the abrading wheel 21 loosely surrounds a permanent magnet 26' whose lower portion is partially loosely disposed within the cavity 24 and whose upper portion extends substantially above the level of the upper planar surface or edge of the annular rim 25.

The magnet 26 is preferably circular and is preferably, but not necessarily, mounted in axial alinement with the abrading Wheel 21 on a stud, shoulder screw or bolt 27 whose reduced u'pper'end is secured in the upper horizontal portion 30 of a shield 31 which may also be termed a magnet supporting bracket. The magnet 26 is preferably loosely mounted on stud 27 so the movement of the blade being sharpened thereagainst may rotate the magnet or, at least, the magnet 26 may be manually rotated to prevent it from becoming excessively worn at one point. The magnet 26 may also be termed as a roller. However, the magnet 26 may be fixed on stud 27, if desired. The shield 31 is substantially circular in plan, but is cut away to expose a portion of the abrading wheel 21 and to form an opening through which the improved blade guiding and positioning means, to be later described, may have free vertical or axial movement. The shield or hood 31' has tab portions 32 integral with the lower portion thereof which extend radially therefrom and are suitably secured to the upper surface of the plate 14, as by screws 34.

Now, in order to support and guide a blade, such as the blade indicated at B in Figures 1 and 6, during a sharpening or honing operation, I have provided an improved'blade positioning and guiding device including a bracket broadly designated at 36 and comprising a relatively thin broad plate 37 which has a downwardly extending projection 40 integral therewith, or suitably secured thereto, and which is shown in the form of a tube having a cavity or bore 41 therein. The projection 40 is mounted for vertical sliding movement on a tubular guide block 42 whose lower end is suitably secured to,

or integral with, an elongated bar 43.

The elongated bar 43 is suitably secured to the upper surface of the plate 14, as by screws 44, and has a cavity or groove 45 in the lower central portion thereof in which an adjustment hand-wheel 46 is disposed. The adjustment wheel 46 is preferably of substantially greater diameter than the width of the bar 43 so that it extends outwardly beyond the bar 43 and is thereby readily accessible to an operator. The adjustment Wheel 46 is fixed on, or integral with, the lower end of an adjustment screw 47 whose lower end bears against the upper surface of plate 14 and whose upper portion is threadably embedded in the lower portion of a blade guide lifting element or rod 50 mounted for vertical sliding movement in the tubular guide member 42 and having a head portion or an enlarged portion 51 on its upper end which is preferably of the same diameter as the external diameter of the tubular guide member 42. s The upper end of the head portion 51 of the blade guide lifting element 50 has a shallow cavity 52 therein in which the lower end of a compression spring 53 is positioned and theupper end of the compression spring 53 bears against the lower surface of the plate 37 of bracket 36. Thus, the bracket 36 is normally urged upwardly to a predetermined position, preferably to where the upper surface thereof is disposed on the same level as the upper surface of the abrading wheel 21, and may be adjusted to this, or any other desired position, by rotating the hand-wheel 46 and screw 47 in the desired direction. The periphery of the hand-wheel 46 is preferably serrated or knurled as shown in Figures 2, 4, and 6.

The inner edge of the plate 37 of bracket 36; that is, the edge thereof adjacent the abrading wheel 21, is formed with an arcuate cavity, recess or notch defining a surface 55 thereon which is preferably of slightly greater radius than the external radius of the abrading wheel 21 and which is maintained concentric with the abrading wheel 21, since the tubular projection 40 of bracket 36 is suitably keyed to the tubular guide member 42, such as by a dog-point set screw 56 (Figure 3). The set screw 56 is threadably secured in the projection 40 of bracket 36 and the dog-point thereof slidably penetrates a vertically extendingkey slot 57 provided in the tubular guide member 42.

Also, in order to prevent rotation of the blade guide lifting element 50 when its position is being varied by rotation of the hand-wheel 46and the screw 47, it will be observed in Figure 3 that the blade guide lifting element or rod 50 is flattened, as at 60, on one side thereof and this flattened surface 60 slides against the inner end of the dog-point of the set screw 56 during vertical adjustment of the blade guide lifting rod 50. will be noted that the depth of the cavity defined by the arcuate surface 55 on the inner edge of the, plate 37 of bracket 36 is such that an imaginary line drawn between opposite side portions 55a of the plate 37, which define portions of the arcuate surface 55, would be spaced radially from the axis of the magnet 26 a distance substantially the same as, or slightly less than, the radius of the magnet 26 so that the portions 55a of the'plate 37 will support the blade B at the cutting edge thereof as the blade is drawn across the upper surface of the abrading wheel 21. This imaginary line may be termed as the chord line of the arcuate surface 55.

Adjustably mounted upon the plate 37 is a blade guiding plate 62 which is of substantially the same shape and size as the plate 37 of bracket 36 and is also provided with a cavity or notch in its inner end defining an arcuate surface 63 and projections 63a at opposite sides of the plate 62. The projections 63a rest upon and coincide with the outer ends of the projections 55a of the plate 37. The plate 62 is normally urged against the upper surface of the plate 37 by means of a compression spring 65 which surrounds a stud 66 shown in the form of a fiat head screw in Figures 5 and 6. The head of the screw 66 is preferably flush or slightly below flush with the upper surface of plate 62 and the shank of the screw 66 loosely penetrates both of the plates 62 and 37 and has a nut 67 threadably mounted on the lower end there of for confining the compression spring 65 against the lower surface of plate 37 immediately adjacent the arcuate surface 55.

During the blade honing or sharpening operation, the blade B is slid against the upper surface of the blade guide plate 62 and the angle at which the blade is sharpened is determined by the attitude of the blade guiding plate 62 relative to the upper surface of the abrading wheel 21, and relative to the upper surface'of the plate 37.

In order to adjust the plate 62 to vary the attitude or the angle thereof, the outer ends of the plates 37 and 62 are provided with respective down-turned

arcuate portions

70 and 71 whose proximal surfaces are disposed in justaposition and the radius of the proximal or mating surfaces of the

projections

70 and 71 is generated about the point at which the tip ends of the projections 63:: on plate 62 engage the upper surfaces of the projections 55a on the plate 37. Thus, when the plate 62 is ad justed relative to plate 37 of bracket 36, the extreme.

front or inner edges of the projections 63a pivot against the extreme front or inner ends of the projections 55a on the plate 37. r In order to lock the plate 62 in the desired adjusted position relative to plate 37, plate 62 is provided with a vertically extending adjustment slot 72 which is loosely penetrated by the shank of a screw 73 having a wing nut 74 threadably mounted on the outer end thereof. The shank of the screw 73 also penetrates the arcuate portion 70 of the plate37 and the. head thereof bears against the inner surface of said arcuate portion 70. Thus, the wing nut 74 may be loosened and the plate 62 manually pivoted about the point at which the projections 63a engage the projections 55a of plate 37 and then the wing nut 74 may be tightened or driven home to lock the plates 62 and 37 in the desired relative positions.

In view of the fact that most blades of a given width are preferably beveled or tapered adjacent the cutting edges-thereof on a common angle, the arcuate portion 71 of the blade guiding plate 62 is provided with avertically extending row of strategically spaced apertures or bores 76 and the arcuate portion 70 of the plate 37 is provided with a single aperture or bore 77. Thus, the plate 62 may be manually moved relative to plate 37 until a predetermined one of the bores 76 is disposed in alinement with the bore 77, during which a positioning pin 80 is slidably inserted in the pre-selected bore 76, and the operator may exert inward pressure on the positioning pin 80 to cause the same to slide into the bore 77 upon registration of the-pre-selected bore 76 with the bore 77. Then, the wing nut 74 may be tightened and the plate 62 will then have been adjusted to a predetermined angular attitude relative to the plate 37 and the upper surface of the abrading wheel-21.

Now, in order to insure that the blade B is held snugly against the blade guiding plate 62, as it is moved to and fro across the upper edge of the annular portion 25 of the abrading wheel 21 and across the upper surface of the plate 62 by the operator, a relatively thin pressure applying plate 85 is provided which is also preferably of substantially the same size and 'shape as the plates 62 and 37-. Like the plates 62 and 37, the inner edge of plate 85' also has anarcuate cavity therein forming an arcuate surface 86 and defining projections 86a at opposite sides of the. plate 85, which projections 86a rest against the inner ends of the projections 63a of the blade guide plate 62.

The outer end of the pressure applying plate 85 is maintained in spaced relationship to the plate 62 by a plurality of suitable spacing members 87, there being twoof said spacing members employed in the present instance which are disposed inwardly of the respective longitudinal side edges of the plate 85. The plate 85 is also maintained in the proper position on the plate 62, so that the arcuate surface 86 coincides with the arcuate surface 63 of plate 62, by means of guide rods or pins 90 which preferably extend downwardly from the spacing blocks or members 87 and loosely penetrate corresponding holes or bores 91 provided therefor in the plate 62 (Figure 7). Of course, when the outer portion of plate 62 is positioned against or in closely spaced relation to the outer portion of the plate 37, the pins 9% which are preferably of substantially greater length than the thickness of the plate 62,, loosely extend through corresponding apertures or bores '92 provided therefor in the plate 37.

In operation, the blade B to be sharpened is inserted between the proximal surfaces of the plates 85 and 62 and the guide pins 9% permit the plate 85 to be raised relative to plate 62 as the blade B is inserted therebetween. Assuming the plate 62 to have previously been adjusted to the desired angle relative, to the plate 37 of bracket 36 and the upper surface of the abrading wheel 21, the parts of the blade supporting and guiding'means then occupy substantially the position shown in Figure 5. The operator then moves the blade inwardly until its sharp edge is disposed against or in close proximity to the periphery of the magnet 26 and then manually exerts downward pressure on the upper surface of the pressure applying plate 85. In so doing, the operator forces the plates 85., 62 and 37 downwardly until the blade B engages the upper surface of the rotating abrading wheel 21' and then regulates the pressure, as desired, as the blade is moved to and fro against the upper surface of the abrading wheel 21.

An important function of the pressure applying plate 85', is to insure that the blade is not tilted longitudinally thereof as it is drawn across the upper surface of the rotating abrading wheel 21, this being insured by the fact that the blade is held against the projections 63a of the blade guiding plate 62 by the projections 86a of the pressure applying plate 85 as pressure is exerted thereon by the operator. If the operator finds that the pressure required to move the

plates

85, 62 and 37 downwardly, from the position of Figure to that of Figure 6, is excessive, the operator merely rotates the hand-wheel 46 to lower the blade guide lifting element 50, thereby reducing the amount at which the spring 53 has to be compressed in order that the blade B engages the upper surface of the abrading wheel 21. Of course, the adjustability of the lifting element 50 also facilitates adjusting the plates 85, 62 and '37 in the event of the upper surface of the abrading wheel 21 becoming excessively worn and also facilitates adjustment of these

plates

85, 62 and 37 when a new abrading wheel 21 is installed on the reduced portion 20 of the motor shaft 16.

it is evident that, as the blade B is drawn across the upper surface of the abrading wheel 21, the molecules at the extreme sharp edge of the blade are attenuated or stretched due to the influence of the magnet 26 thereby producing an extremely sharp or keen cutting edge on the blade.

In order to facilitate transporting the improved blade sharpening apparatus from one place to another, a curved or substantially semi-circular handle 95 is pivotally mounted at diametrically opposed points, as at 96, on the side walls of the bracket or shield 31, which handle 95 preferably has an internal radius substantially the same, or slightly greater than, the external radius of the vertical wall of the shield 31 so that, when the handle 95 is not in use, it may be swung downwardly out of the way to substantially the position shown in Figures 1, 2, 5 and 6.

if so desired, the pressure applying plate may be made from a flexible material and the pins 9t") fixed to plate 62. However, when the pins are loose in bores 91 and 92, this facilitates removing plate 35 for cleaning the upper surface of plate 62.

it will be noted that the upper end or plate 14 of the cylinder is positioned in accurate right-angular relation to the motor shaft 16 to make possible a perfectly square and perpendicular relationship of all the working parts of the device thus insuring precision end results of the work done.

It is thus seen that I have provided an improved blade sharpening apparatus wherein the theory of magnetostriction is utilized to attenuate or stretch the molecules of the blade as it is being sharpened, and wherein an improved means is provided for guiding and positioning the blade as it is drawn across the planar face of the grinding or abrading wheel 21, which guiding means insures that the blade willbe honed or sharpened at a predetermined angle which is uniform throughout the length of the blade being sharpened.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only, and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. Apparatus for sharpening blades, such as knives and the like, comprising a rotatable drum having an abrasive outer end surface thereon and also having a cavity .in its outer end, a circular magnet partially disposed in said cavity, means ioosely supporting said magnet for rotation about an axis substantially parallel to the axis of said drum, a blade guide comprising outer and inner complementary plates extending substantially radially from said drum and having coinciding concave arcuate edges thereon adiacent said drum, said arcuate edges being of a radius substantially the same the external radius of said drum, means maintaining said arcuate edges substantially concentric with said drum, first resilient means normaliy maintaining the outer surface of the outer plate in a position slightly outwardly of said abrasive outer surface of said drum, means for adjusting said outer plate as to angularity relative to the inner plate and parallel to the axis of said drum, and second resilient means for maintaining the innermost ends of said outer and inner plates in contacting.

engagement.

2. In a structure according to claim 1, means for adjusting the first resilient means parallel to the axis of said drum. 7 v

3. In a structure according to claim 1, said means for adjusting the outer plate relative to the inner plate comprising said outer and inner complementary plates being formed with complementary arcuate portions on the outer ends thereof remote from the drum, said arcuate portions having mating surfaces of a radius generated about the point at which the innermost ends of said complementary plates contact each other, one of said arcuate portions having an adjustment slot therein extending substantially parallel to the axis of said drum, and a bolt carrier by the other of said arcuate portions and extending through said adjustment slot for securing the outer plate in the desired adjusted position relative to the inner plate.

4. Apparatus for sharpening elongated blades, such as knives and the like, comprising a rotatable drum having an abrasive outer end surface thereon, said drum having a cavity in its outer end, a circular magnet partially disposed within said cavity, means supporting said magnet independently of said drum, a blade guide extending outwardly and substantially radially from said drum, resilient means normally maintaining the inner ege of said blade guide adjacent the drum in a position slightly outwardly of the abrasive end surface of the drum, the inner edge of said blade guide being provided with a cavity defining an arcuate inner edge surface thereon substantially concentric with the drum, means for adjusting the blade guide as to angularity relative to the outer end surface of the drum, a pressure applying plate, means loosely guiding the pressure applying plate on the outer surface of the blade guide, and the inner edge surface of said pressure applying plate being of substantially the same configuration as the inner edge surface of the blade guide whereby a blade may be inserted between the pressure applying plate and the blade guide and pressure may be manually applied to the pressure applying plate to urge the blade guide toward the outer end of said drum and to urge the blade against the'outer surface of the drum as the blade is manually moved longitudinally for sharpening the blade at a predetermined uniform angle throughout its length while causing the edge of the blade to be attracted by the magnet for attenuating the molecules therein.

5. In a structure according to claim 4, said blade guide comprising a first and second complementary plates, said plates being provided with complementary arcuate portions on the outer ends thereof remote from the drum, said arcuate portions having mating surfaces of a radius generated about the point at which the innermost ends of said complementary plates contact each other, one of said complementary arcuate portions having an adjustment slot therein extending substantially parallel to the axis of said drum, a bolt carried by the other of said arcuate portions and extending through said adjustment slot for securing the first plate in the desired adjusted position relative to the second plate, means supporting the second plate for movement parallel to the axis of the drum, said resilient means serving to normally urge said first and second complementary plates outwardly, and means for adjusting said resilient means to facilitate positioning the first and second complementary plates in the desired position relative to the abrasive outer surface of the drum.

6. Apparatus for sharpening elongated blades, such as knives and the like, comprising a rotatable drum adapted to be disposed on a vertical axis and having an abrasive upper end surface thereon, said drum having a cavity in its upper end, a circular magnet disposed within said cavity, means supporting said magnet independently of said drum, a blade guide extending outwardly, and in a plane substantially radially of, said drum, resilient means normally maintaining the inner edge of said blade guide adjacent the drum in a position slightly above the level of the abrasive end surface of the drum, the inner edge of saidblade guide being provided with a cavity defining an arcuate surface thereon of slightly greater radius than, and being substantially concentric with, that of the radius of the drum, means for adjusting the blade guide as toangularity longitudinally of the axis of the drum, a pressure applying plate, means loosely guiding the pressure applying plate on the upper surface of the blade guide, and the inner edge of said pressure applying plate being of substantially the same configuration as the arcuate inner surface of the blade guide whereby a blade may be inserted between the pressure applying plate and the blade guide and downward pressure may be manually applied to the presusre applying plate to urge the blade guide downwardly and to urge the blade against the upper surface of the drum as the blade is manually moved longitudinally for sharpening the blade at a predetermined uniform angle throughout its length and while causing the edge of the blade to be attracted by the magnet for attenuating the molecules therein.

7. In a structure according to claim 6, said blade guide comprising upper and lower complementary plates, said plates being provided with complementary downturned arcuate portions on the outer ends thereof provided with mating surfaces of a radius generated about the point at which the innermost ends of said complementary plates contact each other, one of said complementary downturned portions having an adjustment slot therein extending substantially parallel to the axis of said drum, a bolt carried by the other of said downturned portions and 7 extending through said adjustment slot for securing the upper plate in the desired adjusted position relative to the lower plate, means supporting the lower plate for vertical movement in parallel relation to the axis of the drum, said resilient means normally urging said complementary plates upwardly, and means for vertically adjusting said resilient means to facilitate positioning the upper and lower complementary plates in the desired position relative to the upper abrasive end surface of the drum.

8. A structure according to claim 7, wherein the inner edges of both the upper and the lower plates are each provided with an arcuate cavity forming coinciding surfaces on the inner edges of the upper and lower plates each having a radius slightly greater than the external radius of the drum, means maintaining the arcuate inner edge surfaces of the upper and lower complementary plates concentric with the axis of said drum, and a second resilient means normally maintaining the innermost ends of the upper and lower complementary plates in contact each with'the other. a

1 9. In a structure according to claim 7, the outermost of the downturned portions of said upper and lower complementary plates having a row of bores therein which row extends in substantially parallel relation to the axis of said drum, the innermost of said downturned arcuate portions having at least one bore therein with which a selected bore in the outermost of said downturned portions may register to facilitate a predetermined angular attitude of the uppermost of the complementary plates relative to the lowermost of the complementary plates.

10. In a structure according to claim 9, a positioning pin adapted to slidably fit in any one of the bores in the outermost downturned portion and the bore in the innermost downturned portion when said downturned portions are positioned in proper relationship.

, ciding concave arcuate edges thereon adjacent said drum, .said arcuate edges being of a radius substantially the same as the external radius ofsaid drum, means maintaining said arcuate edges substantially: concentric; with said: drum,.first resilientmeans normally'maintaining theouter surface of the outer plate in: a position slightly outwardly of said abrasive outer end surface of said drum, means for adjusting said outer plate as to angularity relative to the inner. plate and parallelto the axis of said'drum, and second resilientmeansfor maintaining the innermost ends of said outer and inner plates in contacting engagement.

12. Apparatus for sharpening elongated blades, such as knives and the like; comprising-arotatable drum having an abrasive outer end surface thereon, said drum having a substantially circular cavity in its outer end, a roller partially disposed within said cavity, means supporting said roller for rotation independently of said drum and substantially parallel to the axis of said drum, a blade guide extending: outwardly and substantially radially from said drum, resilient means normally maintaining the inner edge of said blade guide adjacent the drum in a position slightly outwardly of the abrasive end surface of the drum, the inner edge of 'said'blade guide being provided with a cavity defining an arcuate inner edge surface thereon substantially concentric with the drum, means for adjusting the blade guide as to angularity relative to the outer end surface of the drum, a pressure applying plate, means loosely guiding the pressure applying plate on the outer surface of the blade guide, and the inner edge surface of said pressure applying plate being of substantially the same configuration as the inner edge surface of the blade guide whereby a blade may be inserted between the pressure applying plate and the blade guide and pressure may be manually applied to the pressure applying plate to urge the blade against the outer end surface of said drum as the blade is manually moved longitudinally for sharpening the blade at a predeten mined uniform angle throughout its length while the edge of the blade moves in engagement with the roller and imparts rotation to said roller to minimize frictional contact between the blade and the roller.

13. Apparatus for sharpening elongated blades, such as knives and the like, comprising a rotatable drum adapted to be disposed on a substantially vertical axis and having an abrasive upper end surface thereon, said rotatable drum having a substantially centrally disposed cavity in its upper end, a motor for driving said drum spaced below the drum, a shaft extending upwardly from said motor and on the upper end of which said drum is secured, a housing for said motor and having an upper wall thereon loosely penetrated by said shaft, a roller at least partially loosely disposed in said cavity and projecting upwardly therefrom, a bracket carried by the upper wall of said housing and having a portion at least partially overlying said drum, a stud carried by said overlying portion of said bracket and on which said roller is rotatably mounted, a blade guide extending outwardly and in a plane substantially radially of said drum, resilient means normally maintaining the inner edge of said blade guide adjacent the drum in a position slightly above the level of the abrasive end surface of the drum, the inner edge of said blade guide being provided with a cavity defining an arcuate surface thereon of slightly greater radius than, and being substantially concentric with, that of the radius of the drum, means for adjusting the blade guide as to angularity longitudinally of the axis of the drum, a pressure applying plate, means loosely guiding the pressure applying plate on the upper surface of the blade guide, and the inner edge of said pressure applying plate being of substantially the same configuration as the arcuate inner surface of the blade guide whereby a blade may be inserted between the pressure applying plate and the blade guide and downward pressure may be manually applied to the pressure applying plate to urge the blade guide downwardly and to urge the blade against the upper surface of the drum as the blade is manually moved longitudinally in engagement with, and imparts rotation 10 to,.the roller forsharpeningthe, blade at a'predetermined; uniform angle throughout its length.

14. In a blade sharpening apparatushaving a frame, motor means having an upright shaft-projectingupwardly- 1 above the level of saidaframe, and arotatable abrading wheel fixed on said shaft and having an abrasive uppersurface thereon; the combination-of. a. blade guide extending outwardly substantially radially of said abrading wheeland having a flat upper surface thereon, the inner edge of said blade guide. adjacent the abrading wheel having an arcuate concave surface thereon ofi substantially the same radius as,.and being;substantially concentric with, the radius ofthe abrading wheel, supporting means carn'edby said frame forv supporting saidblade guide forvertical movement? substantially parallel to the axis of and past the abrading; wheel, resilient means normally maintaining the blade guide in a raisedposition with its upper surface disposed above the level of, the, abrading wheel, meansv onsaid supporting means. for; pivotally supportingthe innermostend of said blade guide on a pivot axis in substantially transverse relation to the axis of the abrading wheel, and means for angularly adjusting said blade guide on said pivot axis whereby the blade to be sharpened may be positioned on the blade guide and the blade guide may be forced downwardly past the abrading wheel as the blade is moved into contact with the upper surface of the abrading wheel for sharpening the same by applying manual downward pressure to the blade as it is moved to and fro across the upper surface of the abrading wheel.

15. In an apparatus for sharpening blades, such as knives and the like, having a driven abrading wheel mounted on a substantially vertical axis and having an abrasive upper surface thereon; the combination of a blade guide comprising upper and lower complementary plates extending substantially radially from said wheel and provided with substantially fiat upper surfaces and also having coinciding concave arcuate edges thereon adjacent said wheel, said arcuate edges being of a radius substantially the same as the external radius of said wheel, means supporting said lower plate for substantially vertical movement and for maintaining the arcuate edges on the upper and lower plates substantially concentric with said wheel, first resilient means normally maintaining the upper surface of the upper plate in a position slightly above the level of said abrading wheel, means for angularly adjusting said upper plate relative to the lower plate and substantially parallel to the axis of said abrading wheel, and second resilient means for maintaining the innermost ends of said upper and lower plates in contacting engagement.

16. A structure according to claim 15 having means for vertically adjusting the first resilient means substantially parallel to the axis of said abrading wheel.

17. A structure according to claim 15 wherein the means for angularly adjusting the upper plate relative to the lower plate comprises complementary arcuate portions on the outer ends of said upper and lower complementary plates remote from the abrading wheel, said arcuate portions having mating surfaces of a radius substantially generated about the point at which the innermost ends of the complementary plates contact each other, one of said arcuate portions having an adjustment slot therein extending substantially parallel to the axis of said abrading wheel, and a bolt carried by the other of said arcuate portions and extending through said adjustment slot for securing the upper plate in the desired angularly adjusted position relative to the lower plate.

18. In a blade sharpening apparatus having a frame, motor means having an upright shaft projecting upwardly above the level of said frame and a rotatable abrading wheel fixed on said shaft and having an abrasive upper surface thereon; the combination of a blade guide extending outwardly substantially radially of said abrading wheel and having a flat upper surface thereon, the inner blade guide on a pivot axis in substantially transverse relation to the axis of the abrading Wheel, means for angularly adjusting said blade guide on said pivot axis, and said concave surface being of suflieient size to clear said abrading Wheel when said blade guide is adjusted at various anglesabout said pivot axis and to clear the wheel during vertical adjustment of the blade guide whereby the blade to be sharpened may be positioned on the blade guide while in raised position and the blade guide may 12 be adjusted downwardly past the abrading wheel to move the blade into contact with the upper surface of the abradi'ng wheel for sharpening the same by applying manual downward pressure to the blade as it is moved to and fro across the upper surface of the abrading wheel.

ReferencesCited in the file of this patent UNITED STATES PATENTS 617,783 Smith Ian. 17, 1899 1,832,539 Ezzell Nov. 17, 1931 2,056,182 Gardner Oct. 6, 1936 2,077,195 Adams Apr. 13, 1937 2,318,764 Dorris May 11,1943 2,522,942" Gillen Sept. 19, 1950 2,645,063 Smith July 14, 1953 FOREIGN PATENTS g j 7 201,338 Great Britain' Aug. 2, 1923' 593,705 Germany Mar. 1, 1934 Great Britain Aug. 6, 1948