US3812626A

US3812626A - Ice skate sharpening device

Info

Publication number: US3812626A
Application number: US00285627A
Authority: US
Inventors: A Thompson
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-01
Filing date: 1972-09-01
Publication date: 1974-05-28
Anticipated expiration: 1991-05-28

Abstract

A portable ice skate sharpening device in the form of an attachment for a conventional hand drill and including a rotary abrasive grinding wheel which is enclosed in a casing having formed therein an opening which exposes a limited portion of the periphery of the rotating wheel and renders the same accessible for application thereto of a skate blade. A removable skate blade positioning unit is positioned within the opening and defines a guide slot through which the skate blade to be sharpened is manually guided to draw the edge of the blade progressively and transversely across the periphery of the wheel, the unit being so designed that the lateral thrust which is applied to the blade incident to its contact with the rotating wheel serves to bring the general plane of the skate blade into coincidence with the axis of rotation of the wheel, thus resulting in a hollow ground skate blade edge the radius of curvature of which lies precisely in the midplane of the skate blade.

Description

United States Patent [191 [111 3,812,626

Thompson 1 May 28, 1974 ICE SKATE SHARPENING DEVICE [76] Inventor: Arnold M. Thompson, Box 172A [57] ABSTRACT Gary Ave., Wheaton, Ill. 60090 A portable ice skate sharpening device in the form of an attachment for a conventional hand drill and in- [22] Filed Sept 1972 cluding a rotary abrasive grinding wheel which is en- [21] Appl. No.: 285,627 closed in a casing having formed therein an opening which ex oses a limited portion of the periphery of h h l d d h 'b] f t e rotatmgw ee an ren erst e same accessi e or [52] U.S.Cl 51/170 PT,5l/l02, 51/228 application thereto of a Skate blade A removable [51] Int. Cl B24b 9/04, B24b 23/02 [58] Field of Search 5] 70 R 170 PT 102 skate blade positioning unit 18 positioned within the 1, opening and defines a guide slot through which the skate blade to be sharpened is manually guided to [56] References Cited draw the edge of the blade progressively and transversely across the periphery of the wheel, the unit UNITED STATES PATENTS being so designed that the lateral thrust which is ap- 522,373 7/1894 Hosack 51/102 UX plied to the blade incident to its contact with the ro- 2,563,013 8/1951 Fell!) 51/102 tating wheel serves to bring the general plane of the g g z skate blade into coincidence with the axis of rotation o nson 2,906,067 9/1959 Hale 51/170 PT of the wheel thus resumng m a hollow ground Skate Primary Examiner-Donald G. Kelly Attorney, Agent, or FirmNorman l-l. Gerlach blade edge the radius of curvature of which lies precisely in the midplane of the skate blade.

9 Claims, 15 Drawing Figures 1 ICE SKATE SHARPENING DEVICE The improved ice skate sharpening device comprising the present invention is designed for use primarily as a portable electric hand drill attachment which requires no bench support when in use. The device also is primarily intended for home use by skate owners and it is so constructed that it may be manipulated by an operator who, with one hand, may steady the device, while with the other hand, the skate blade undergoing sharpening may be operatively drawn progressively across the periphery of a rotating abrasive grinding wheel which derives its rotary motion from the chuck which is associated with the portable hand drill. The invention is, however, capable of other uses and the same may, if desired and with or without modification as required, be designed for bench use wherein the device is fixedly clamped to a suitable bench, stand, or other support and the abrasive wheel is caused to derive its rotary motion from a rotary lathe or other chuck or from any suitable coupling whereby rotary motion is imparted to the abrasive wheel. Irrespective, however, of the particular use to which the present invention may be put, the essential features of the invention are at all times preserved.

Present day ice skate sharpening devices which are intended for home use or for use in the field are fairly well standardized and they consist of an elongated tubular'shell which encloses a cylindrical abrasive element or stone of rod-like design, the shell being slotted longitudinally so as to expose a limited peripheral area of the abrasive element. Skate blade sharpening operations are performed by the simple expedient of drawing the skate blade progressively through the slot in the shell while at the same time causing the blade edge undergoing sharpening to slide longitudinally along the abrasive element. Such skate blade sharpening devices are possessed of certain limitations, principal among which is the inability thereof to produce linearly straight, parallel, and uniformly sharp ice-cutting edges on opposite sides of the hollow ground curvature which extends along the skating surface or edge of the blade. In order to accommodate varying widths of skate blades such as obtain where figure skates, hockey skates, and racing skates are concerned, the blade? receiving slot is invariably made of a width which will accommodate the widest of such blades. Actually, such slot is made a few thousandths of an inch wider than the width of the widest blade so that there will be a clearance for ease of sliding movement of the blade through the slot. Thus, with an abrasive element or stone which has the desired hollow grind curvature, great pains must be taken not to incline the skate blade as it is being drawn or pulled through the slot, and also lateral centering of the blade must be preserved otherwise one .of the two parallel ice-cutting edges becomes displaced vertically with relation to the other edge. The average unskilled operator is unable to control skate blade rocking in the slot or skate blade centering and thus such aforementioned prior art skate blade sharpening devices are seldom relied upon for full skate blade sharpening operations, but rather, they are used for touch-up" jobs. Similar limitations are prevalent in connection with various jigs which have been devised for presenting a skate blade to be sharpened to a rotating grinding wheel by drawing the blade through a slot.

In the latter instance, out-of-true skate blade sharpening is more likely to occur than with pocket-type sharpening devices inasmuch as one false movement of the skate blade results in serious, and sometimes deleterious, blade damage.

The present invention is designed to overcome the above-noted limitations that are attendant upon the construction and use of conventional skate sharpening devices regardless of whether the same be pocket-type or powered. Accordingly, in carrying out the invention, there is provided a hand drill attachment having a ro tating grinding wheel of a diameter commensurate with the desired curvature of the hollow grind which is to be applied to the skate blade, the wheel having a drive shaft which may be conveniently received in the chuck of an electrically-powered portable hand drill or the like. A cylindrical casing closely surrounds the rotary abrasive grinding wheel and is formed with a longitudinally extending peripheral slot which exposes a limited peripheral area of the grinding wheel so that a skate blade which is drawn or pulled progressively through the slot encounters the wheel in a transverse direction to the end that the wheel will ream out the desired hollow grind in the skating edge of the blade.

One of the principal features of the present invention resides in the provision of a skate blade positioning assembly or unit which is capable of being removably clamped in position within the casing slot and, when so positioned, defines a secondary skate blade guide slot which, when the skate blade is drawn or pulled therethrough, maintains the blade properly addressed to the periphery of the abrasive wheel so that there will be neither angular tilting of the blade within the secondary slot during grinding operations nor lateral displacement of the blade within said slot. Stated otherwise, the blade will at all times during its traverse of the secondary slot remain in a true radial plane with respect to the abrasive wheel so that there will obtain along the skating edge of the blade a true and symmetrical hollow grind curvature which leans neither to the right nor to the left and which is uniform throughout its length. The provision of a skate sharpening device such as has briefly been outlined above constitutes the principal object of the present invention.

it is a further object of the invention to provide in connection with an ice skate sharpening device of the character under consideration a skate-positioning unit wherein there are provided adjusting means whereby the width of the aforementioned secondary slot through which the skate blade is drawn or pulled may be varied. This adjusting means s provided not for the purpose of accommodating skate blades of varying widths, but rather for adjusting the lateral inward spring pressure of the slot sides against the blade sides to attain ease of skate blade manipulation, as well as to compensate for any deterioration in spring pressure which may take place after a prolonged period of use of the device.

The provision of an ice skate sharpening device which is extremely simple in its construction and, therefore, may be manufactured at a low cost; one which is comprised of a minimum number of parts and, therefore, is unlikely to get out of order; one which is rugged and durable and, therefore, will withstand rough usage; one whichis capable of ease of assembly and dismantlement for purposes of inspection of parts, replacement or repair; one which is small and compact and, therefore, is not only readily transportable but also may be conveniently operated while being supported entirely on the person of the user without requiring bench or stand support; one which requires no particular degree of skill for its successful operation and, therefore, may be used by unskilled juvenile skaters; one which is attractive in its appearance and pleasing in its design; and one which, otherwise, is well adapted to perform the services required of it, are further desirable features which have been borne in mind in the production and development of the present invention.

Other objects and advantages of the invention, not at this time enumerated, will become readily apparent as the nature of the invention is better understood from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter described and are more particu' larly pointed out in the claims at the conclusion hereof.

FIG. 3 is a side elevational view of the device;

FIG. 4 is a longitudinal sectional; view taken on the line '4-4 of FIG. 2; a

FIG. 5 is a transverse sectional view of that portion of the device which has the rotary grinding wheel;

FIG. 6 is a top plan view of the device;

FIG. 7 is an enlarged top plan view of the skate blade positioning head which is employed in connection with the invention;

FIG. 8 is a sectional view taken on the line 8-8 of FIG. 7, the view being turned 90;

FIG. 9 is a transverse sectional view taken on the line 9-9 of FIG. 7;

FIG. 10 is a sectional view similar to FIG. 5 but showing a modified form of the skate sharpening device;

FIG. 11 is an enlarged exploded perspective view of the composite grinding wheel housing which is employed in connection with the present invention;

FIG. 12 is an enlarged perspective view of the grinding wheel and shaft assembly which is employed in connection with the invention;

FIG. 13 is an enlarged, exploded perspective view illustrating the component parts ofa particular skate blade positioning assembly by means of which a skate blade to be sharpened is caused to address the grinding wheel in precise grinding position;

FIG. 14 is a diagrammatic view, entirely schematic in its representation. illustrating certain frictionallyderived skate blade erecting phenomena whichbecome prevalent when blade-sharpening operations are initi: ated by application of a skate blade to the grinding wheel of the form of the invention'which is shown in FIG. 1; and g FIG. 15 is a diagrammatic view similar to F IG. 14 but illustrating the involved phenomena when a skate blade vention which is shown in FIG. 10 of the drawings.

is applied to the grinding wheel of the form of the in- Referring now to the drawings in detail and in partic? ular to FIGS. 1 to 3, inclusive, and also FIG. 6, a skate sharpening device embodying the principles of the present invention is designated in its entirety by the reference numeral 10 and, for proper operation thereof in the sharpening of a skate blade, it is designed for cooperation with a rotary chuck assembly such as the assembly which is fragmentarily illustrated in FIG. 1 and designated by the reference numeral 12. Preferably, but not necessarily, the skate sharpening device 10 is designed for home use by the individual skate owner, utilizing a conventional portable pistol-grip type hand drill having a chuck assembly such as the one illustrated herein. Moreover, when so used, the operator will conveniently, support the drill in his or her lap or on a table or other support while holding the device 10 against rotation bodily with one hand and while manipulating the skate blade undergoing sharpening with the other hand, all in a manner that will be made clear presently when the nature of the invention is better understood. It is within the purview of the invention, however, that the device 10 may be employed in the commercial sharpening of skate blades by a small shop operator, in which case bench support of the hand drill orr other power tool having a chuck such as the chuck assembly 12 may be resorted to if desired, while rotation of the skate sharpening device may be prevented by any suitable torque-arresting reaction clamping means.

Still referring to FIGS. 1 to 3, inclusive, and FIG. 6, and additionally to FIG. 4, briefly the skate sharpening device 10 involves in its general organization a tubular casing 14 which is of generally cylindrical configuration and within which there is disposed a rotary abrasive grinding wheel16. The latter is supported on a drive shaft 18, the rear end of which is designed for reception by the chuck assembly 12. A major sector of the grinding wheel 16 is enclosed within andshielded by the casing 14, but a limited peripheralregion of the wheel is exposed for skate sharpening purposes by reason of the existence of a peripheral slot 20 (see FIGS. 1, 2, 5, and 11) in the casing 14. In order to control the disposition of the skate blade which is undergoing sharpening and to apply ti to the grinding wheel 16 for sharpening purposes at a 0 angle (i.e., so that it lies in the vertical diametric plane of the grinding wheel axis), a skate blade positioning unit or assembly 22 is removably received within the slot 20. This assembly 22 constitutes one of the principal features of the present invention and, as will be set forth in greater detail hereafte r, the assembly is so designed and is so related to the grinding wheel 16 positionally' that practically noskill is required in order to bring the skate blade into proper grinding position, it being necessary only for the operator to introduce the blade in an approximate tangential relation to the grinding wheel; after which the frictional force which the periphery of the rotating grinding wheel offers to the adjacent edge of the skate blade which is undergoing sharpening, automatically erects the skate blade, so to speak, to a precise vertical position wherein the plane of the blade and the diametric plane of the grinding wheel are coincident, thereby resulting in a precise hollow grinding operation upon the edge of the skate blade wherein the center of curvature of the blade edgeconcavity lies precisely in the median plane of the blade. Aswill also be made clear presently, the skate blade positioning assembly 22 is removably received within the slot 20 for the purpose of head substitution in order to accommodate skate blades of different widths as, for example, the blades which are associated with figure skates, hockey skates, and racing skates.

Considering the skate sharpening device in greater detail, the casing 14 is comprised of three principal parts, namely, a main body portion 24, an end cap 26 (see FIGS. 1, 3 and 11), and a bearing sleeve 28. The main body portion includes an outer cylindrical wall 30, an annular radial and wall 32, and a rearwardly extending cylindrical wall 34 of reduced diameter. The forward rim of the cylindrical wall 30 is closed by means of the end cap 26 which is telescopically received within the wall 34 and is provided with a radial rim flange 36 (see FIG. 4) which seats on the rim of the wall 30. A pair of locking screws 38 (see FIG. 6) serves releasably to hold the end cap in position on the body portion 24.

The body portion 24 of the casing 14 establishes a grinding wheel housing within which the grinding wheel 16 rotates, the latter being mounted on the forward end of the shaft 18 which projects axially through the bearing sleeve 28 and into the housing. A clamping nut 40 which s threadedly received on the extreme forward end of the shaft 18 serves to force the grinding wheel 18 rearwardly against a washer 41 which, in turn, bears against a shoulder 42 on the shaft. The shaft 18 is rotatably supported in the casing 14 by means of a sealed ball bearing assembly 44, the outer race of which is press-fitted in an annular recess 45 in the central portion of the annular radial end wall 32, and the inner race of which is straddled by the aforementioned washer 41 and a snap ring 46 in an annular groove'in the shaft 18. The bearing sleeve 28 is provided for the purpose of lending axial stability to the shaft 18 and, accordingly, this sleeve has its forward end region threadedly received as indicated at 48 (see FIG. 4) within the rearwardly extending cylindrical wall 34 of the main body portion of the casing 14 and supports at its rear end a shaft bushing 50 having a radial rim flange 52 which seats on the rear circular rim of the bearing sleeve 28. The bushing 50 affords a bearing support for the rear end of the rotatable shaft 18- at a region appreciably removed from the bearing 44 so that these two bearing supports 50 and 44 maintain the shaft 18 in its proper coaxial relationship with respect to the casing 14. The extreme rear end of the shaft 18 is formed with a reduced section 54 which is designed for reception in the chuck assembly 12 of the hand drill or other power tool by means of which the skate sharpening device 10 is powered.

Referring now to all views of the drawings, but with particular reference to FIGS. 1 to 9, inclusive, wherein the preferred form of the invention is isclosed, the previously mentioned skate positioning assembly 22 is a self-contained unit andconsists of a rigid, one-piece, frame-like support (see FIG. 13) having two substantially identical, laterally spaced, arched,

side wings

62 and 64, the latter being connected together at their ends by transverse base struts 66 and 68. The side wing 62 has formed therein a bore 70 which receives a screw 72 (see FIG. 8) by means of which a shoe-like wear plate 74 having a tapped hole 76 therein may be fixedly clamped to the inside face of said side wing 62. The side wing 64 has formed therein a socket 78 within which there is seated the outer end of a helical compression spring 80. The inner end of the spring 80 projects outwards of the inner end of the socket 78. An adjusting screw 82 projects loosely through a hole in the bottom wall of the socket 78 and has the free end of the shank received in a tapped hole 84 in an adjustable shoe-like wear plate 86. The shank of the screw 82 also extends loosely through the spring, and the head of the screw is located adjacent to the outer side surface of the side wing 64 and serves to limit inward sliding movement of the screw and the wear plate 86. The wear plate 86 is spaced inwards of the inner side surface of the side wing 64 and is yieldingly held in place by the action of the spring 80.

As best shown in FIGS. 6, 7 and 8 of the drawings, when the two

wear plates

74 and 86 are assembled upon the frame-like support 60, they assume spacedapart positions between the two

arched side wings

62 and 64 with the wear plate 74 fitting against the inside face of the side wing 62 and with the wear plate 86 assuming a position slightly spaced from the inside face of the side wing 64. In this assembled position, these two wear plates define therebetween a skate bladereceiving channel or slot 88 (see FIGS. 6, 7 and 8) through which the blade is adapted to be drawn in a longitudinal direction during blade sharpening operations while the edge of the blade which is undergoing sharpening contacts the periphery of the rotating grinding wheel 16 as shown in FIG. 5.

Referring now to FIGS. 7 and 8, it will be noted that the spring 80 is interposed between the bottomwall of the socket 78 and the wear plate 86 so that this spring yieldingly biases the wear plate inwardly of the skate blade-receiving slot 88. By rotating the adjusting screw 82 in one direction or the other, the wear plate 86 will be drawn toward the side wing 64 or forced away therefrom, as the case may be, and thus, rotation of the screw 82 serves to adjust the effective width of the skate blade-receiving slot 88 in order to accommodate skate blades of varying widths.

In order to supply torque reaction to the two wear plates and prevent turning motion thereof when either the clamping screw 72 or the adjusting screw 82 is rotated, each

side wing

62 and 64 is formed with a pair of narrow horizontal ledges 89 (see FIGS. 6, 7, 8, 9 and 13) on which the opposite ends of the

wear plates

74 and 86 normally rest when they are operatively installed on the frame-like support 60.

In order releasably and removably to install the skate blade positioning assembly 22 within he peripheral slot 20 in the casing 14, one end of the arched side wing 64 is provided with a vertical bore 90 (see FIG. 13), and a tapped socket 92 is formed in that portion of the annular radial end wall 32 which defines the bottom of the slot 20, such socket being for reception of a clamping screw 94 (see FIGS. 1 and 6) by means of which the frame-like support 60, and consequently, the entire skate blade positioning assembly 22, may be fixedly secured within the slot 20. The clamping screw 94 constitutes the sole fastening means for the skate blade positioning assembly 22 within the slot 20 and thus this screw, which is disposed at one comer of the frame-like support 60, makes it possible to install the assembly 22 within the slot only in its effective operative position, reversal of the assembly being impossible.

A careful consideration of FIGS. 2 and 4 will reveal the fact that the peripheral slot 20 which is formed in the casing 14 and the end cap 26 is cut on a small angle bias with respect to a diametric planeof the grinding wheel 16, which is to say that the central plane of the slot 20 does not pass through the longitudinal combined axis of the grinding wheel and the shaft 18. The angle involved preferably is on the order of 2. Thus, when the skate blade-positioning assembly 22 is operatively installed in this slot 20, the central plane of the blade-receiving slot 88 is also on a small angle bias inasmuch as the entire assembly 22 becomes angularly disposed when it is inserted in the slot 20.

With the assembly 22 being thus angularly inclined, it is obvious that when a skate blade such as the blade B of FIG. 5 is initially inserted in the blade-receiving slot 88 as shown in dotted lines, and the edge of the blade is brought into contact with the periphery of the grinding wheel 16, the general plane of the blade will also be inclined with respect to the vertical diametric plane of the grinding wheel 16, this inclination beingschematically illustrated by the angle 0 in FIG. 14. This inclination of the skate blade is predicated upon the insertion of the blade into the slot 88 by the average unskilled operator, usually a child, who will push the blade into the slot in amanner that will give himthe least resistance. The net result of this initial angular application of the skate blade B, to the grinding wheel 16 is schematically illustrated by dotted lines in FIG. 14 where it will be observed that one side edge of the blade B will be brought into contact with the rotating grinding wheel. Ordinarily, if skate blade sharpening operations were to continue on this angular bias, an improper hollow grinding of blade would result. However,

, due to the relatively great frictional force which is applied transversely to the skate blade B due to its contact with the periphery of the rotating grinding wheel which rotates in the counterclockwise direction as shown by the arrow in FIG. 14, the tendency for the blade is to erect itself so that it assumes the full-line position shown in this view whereinthe general plane of the blade passes through the combined longitudinal axis of the wheel 16 and the shaft 18. In approaching this vertical position, the side of the blade B pivots about a horizontal fulcrum axis which is established by the adjacent lower corner edge of the fixed wear plate 74, this fulcrum axis being designated by the axis X in FIG. 14. As the blade B continues to erect itself as previously set forth, the spring-biased wear plate 86 on the opposite side of the blade B rides inwardly on the adjacent side of the blade B from the dotted line position thereof to the full-line position, this wear plate finally assuming a vertical position alongside the skate blade'while the fixed wear plate 74, of course, remains inclined. In-its final erect condition, the blade assumes a floating condition, the friction of the grinding wheel 16 tending to force the bottom portion of the blade to the left as viewed in FIG.-14, and the spring 80 assimilating the backwardjforce which is applied to the wear plate 86.

The rate" or strength of the spring 80 is selected sothat a proper condition of bala'nce-of the blade B is attained wherein the blade is substantially vertical or at least so nearly vertical that the hollow grind which is effected upon the skate blade presents a center of cur I vature which lies within the vertical diametric plane of the grinding wheel or so close thereto that-no significant canting of the hollow grind gurvature takes place.

In FIG. 10, a slightly modified form of the invention is shown. In this view, a skate sharpening device 110 embodies a grinding wheel 16 andv a skate bladepositioning assembly 22 which are identical to those previously described in connection with the form of the invention shown in FIGS. 1 through 9 and which, therefore, have been designated by identical reference numerals so that a description thereof is deemed to be unnecessary. The grinding wheel casing 114 of the device 110, however, is slightly different from the casing 14 of the device 10, the only difference being in the nature of the slot 120 which is formed in the cylindrical wall, the radial end wall, and the end cap 126 of the device 110. Apart from the provision of the slot 120, the two skate sharpening devices 10 and remain substantially the same and, therefore, in order to avoid needless repetition of description, similar reference numerals but of a higher order have been applied to the corresponding parts as between the casing structure or arrangements illustrated in FIGS. 10 and 2.

Whereas, in the previously described form of the invention, the slot 20 is cut in the'casing 14 on a slanting bias as heretofore mentioned, the slot in the modified form of the invention is cut in a radial direction so that it possesses no slant. However, this slot is tangentially offset with respect to the periphery of the grinding wheel 16 and, as a result, when the skate bladepositioning assembly 22 of the device 110 is operatively installed in this slot, the two wear plates 74'and 86 are vertical and define therebetween a skate bladereceiving slot 188 which is also vertical. The slot 120, and consequently, the blade-positioning assembly 122, is offset counter to the direction of rotation of the grinding wheel 16 as schematically illustrated in FIG. 15 and, therefore, as is the case in the previously described form of the invention, a skate blade such as the blade B, when inserted into the vertical or radially extending slot 188 as shown in dotted lines in FIG. 15 will engage the grinding wheel 16 at one corner of the skate blade. However, immediately upon frictional contact between the skate blade B and the grinding wheel 16, the originally erect blade B 'will be urged to the left as shown by full lines in FIG. 15 so that'one side thereof will pivot about the fulcrum axis X whichis established by the adjacent lower corner edge of the wear plate 74, and come to rest in a floating inclined position as shown in full lines in FIG. 15. In this inclined position,

the general plane of the skate blade B will line in a diametric plane which passes through the combined axis of the grinding wheel 16 and its shaft 18.

A brief comparison between the device of FIGS. 2 and 14 on theone hand, and the device of FIGS. 10 and 15 on the other hand, may be hade by stating that in the first instance the skate blade B enters the slot 88 in an angularly-displaced non-radial -or secantial direction and is forced. by frictional contact with the grinding wheel into a truly radial or vertical position. In the second instance, the skate blade B enters the slot 188 in a vertical, but non-radial, secantial direction and is forced by therotating grinding wheel into a slanting but truly radial position. In either event, since the fully sharpened skate blades B andd B are acted upon by the grinding wheel for blade-sharpening purposes while they extend radially of the grinding wheel, the net result is the same.

It will be understood that the terms fverticalf and horizontal as employed herein refer to directions which obtain when the skate-sharpening devices 10 or 110 are positioned as shown in FIGS. 2 to 6, inclusive,

and FIG. 10 with the

slots

20 or 120 being disposed at the extreme uppermost sector of the casings 14 and 114, respectively. It will also be understood that when a particular skate blade is undergoing sharpening with the devices of the present invention, the blade will be drawn longitudinally through the

slot

88 or 188 in the usual manner of skate-sharpening operations with skate-sharpening devices having skate bladepositioning slots which guide the skate blade against a skate-sharpening stone or wheel. Ordinarily, in using the skate-sharpening device 10 or 110, after the reduced section 54 of the grinding wheel shaft 18 has been operatively clamped in the chuck 12 of an electric hand drill, the trigger control of such drill will be set to its permanent on" position and the hand drill will then be placed in the lap of the user while at the same time one hand will be applied to the casing 14 to hold the device while at the same time preventing bodily rotation thereof due to chuck rotation. With the hand drill and skate-sharpening device thus supported, the other hand of the user may conveniently be employed for performing the necessary skate blade manipulation in drawing or pulling the same longitudinally along the through

slot

88 or 188 which is afforded by the skate blade positioning assembly 22 or 122.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit of the invention. For example, whereas the slot which is provided in the casing 14 and the end cap 26 is cut on a slanting bias as previously described, it is within the purview of the invention to fashion the

wear plates

74 and 86, or their mountings, in the assembly 22 so that these wear plates establish an inclined skate-positioning channel 88 which initially guides the skate blade against the grinding wheel in a non-erect or slanting position but in which these wear plates function when the skate blade is frictionally engaged by the grinding wheel to bring the skate blade to an erect grinding position. Therefore, only insofar as the invention is particularly pointed out in the accompanying claims in the same to be limited.

Having thus described the invention what I claim as new and desire to secure by letters patent is:

l. A portable skate blade sharpening device adapted to hollow grind the effective supporting edge of a skate blade and comprising a drive shaft having a rear end adapted for connection to a power drive source, a circular abrasive grinding wheel mounted fixedly on the front end of the shaft, a tubular casing encompassing said wheel and a portion of the drive shaft, said casing having a rear end wall through which the drive shaft projects rearwardly, and a front wall, bearing means interposed between the drive shaft and casing and serving rotatably to support the shaft and the wheel, said casing and rear walls being relieved to provide a longitudinally extending blade-receiving slot which exposes a limited peripheral region of the wheel for transverse application thereto of the skate blade at such time as the edge region of the latter is drawn progressively and longitudinally through said slot, and blade positioning means removably mounted within said slot and defining a secondary slot for sliding reception therein of the skate blade, one side wall of said secondary slot being laterally yieldable and normally serving to displace the skate blade and compress the same against the opposite side wall of said secondary slot, said latter side wall being fixed with respect to the casing.

2. A portable skate blade sharpening device as set forth in claim 1 and wherein the yieldable side wall is disposed on the side of the secondary slot from which points on the periphery of the grinding wheel recede during wheel rotation.

3. A portable skate blade sharpening device as set forth in claim 2 and wherein said blade positioning means comprises a fixed wear plate and a movable wear plate, said wear plates defining therebetween said secondary slot, the opposed faces of said wear plates establishing said fixed and yieldable side walls respectively, and spring means yieldingly urging said yieldable wear plate toward said fixed wear plate.

4. A portable skate blade sharpening device as set forth in claim 3 and wherein the side walls of said secondary slot normally lie in parallel spaced apart planes which are inclined at a small angle relative to a diametric plane of the grinding wheel, the direction of inclination of such walls being such that normally they serve to guide the skate blade against the periphery of the grinding wheel at a point in advance of said diametric plane relative to the rotary motion of the wheel.

5. A portable skate blade sharpening device as set forth in claim 3 and wherein the forward end of the drive shaft is threaded and projects axially through the grinding wheel, a clamping nut is received on said threaded end of the shaft and serves to clamp the wheel against an annular shoulder on the shaft, and said front end wall is in the form of a removable end cap which seats on the forward rim of the outer cylindrical casing wall and which, when removed therefrom, affords access to said clamping nut for grinding wheel replacement purposes.

6. A portable skate blade sharpening device as set forth in claim 5 and wherein said bearing means is in the form of a sealed ball bearing unit which is pressfitted centrally in said rear end wall, and the casing includes an elongated rearwardly extending bearing sleeve which is concentric with the drive shaft and which carries a shaft bushing at its rear end.

7. A portable skate blade sharpening device as set forth in claim 6 and wherein said fixed and movable wear plates are operatively mounted on a frame-like support which fits snugly within said slot in the casing, and said support is removably secured in position within said latter slot by means of a clamping screw which is threadedly received in a laterally offset tapped hole in one of the walls of said casing whereby reversal of the support, and consequently, the wear plates, is prevented.

8. A portable skate blade sharpening device as set forth in claim 7 and wherein said spring means comprises a helical compression spring which is interposed between the movable wear plate and said frame-like support, and a compression adjusting screw projects loosely through a portion of said support and also through said compression spring and is threadedly received in said movable wear plate.

9. A portable skate blade sharpening device as set forth in claim 3 and wherein the side walls of said secondary slot normally lie in parallel spaced apart planes which are parallel to a diametric plane of the grinding wheel and which are equally spaced from a medial plane which is offset laterally from said diametric plane in the direction of advancing points on the periphery of the rotating grinding wheel.

Claims

1. A portable skate blade sharpening device adapted to hollow grind the effective supporting edge of a skate blade and comprising a drive shaft having a rear end adapted for connection to a power drive source, a circular abrasive grinding wheel mounted fixedly on the front end of the shaft, a tubular casing encompassing said wheel and a portion of the drive shaft, said casing having a rear end wall through which the drive shaft projects rearwardly, and a front wall, bearing means interposed between the drive shaft and casing and serving rotatably to support the shaft and the wheel, said casing and rear walls being relieved to provide a longitudinally extending blade-receiving slot which exposes a limited peripheral region of the wheel for transverse application thereto of the skate blade at such time as the edge region of the latter is drawn progressively and longitudinally through said slot, and blade positioning means removably mounted within said slot and defining a secondary slot for sliding reception therein of the skate blade, one side wall of said secondary slot being laterally yieldable and normally serving to displace the skate blade and compress the same against the opposite side wall of said secondary slot, said latter side wall being fixed with respect to the casing.

6. A portable skate blade sharpening device as set forth in claim 5 and wherein said bearing means is in the form of a sealed ball bearing unit which is press-fitted centrally in said rear end wall, and the casing includes an elongated rearwardly extending bearing sleeve which is concentric with the drive shaft and which carries a shaft bushing at its rear end.