This invention relates to sharpening blades and more specifically to sharpening multiple blades simultaneously with complex profiles.
In winter sports such as ice skating and hockey the blades of an ice skate are the point of contact for all of the forces generated in turns, spins, jumps, stops, gathering speed etc. Ice skates typically have a convex shape along a length of the skate blade and a concave shape across the width of the blade, defining two edges along the length of the blade. A skater can use either of these two edges in executing maneuvers on the ice surface. In order to maintain a desired blade configuration, a skate sharpening machine must be employed to re-grind the lower surface of the blade to create a groove along the length of the blade according to the desired profile
As skate blades differ from one pair to another, the sharpening of the skate blade to a required profile has long been considered to be part art and part science. Within the prior art the operator of a skate sharpening machine is required to first dress a grinding wheel to have the desired contour and then ensure that during the grinding process the centerline of the contour on a wheel coincides with the centerline of the blade along its full length. If this is not done an irregular groove will be created along the length of the blade, with one edge being higher/lower than the other.
Further with use a dressing of the skate sharpening grinding wheel itself must be carried out. This is traditionally carried out using a single point diamond dresser that is pivoted about an axis generally perpendicular to an axis of rotation of the grinding wheel. The single point diamond dresser is slowly swung through an arc that intersects the outer periphery of the grinding wheel, removing material from the wheel to create and define a grinding wheel contour. Since the dresser pivots, the contour formed on the grinding wheel is anything from a convex arcuate surface with a radius typically in the range of ⅜ inch to 1⅝ inch through to a triangular profile. Once the grinding wheel contour has been created, it may be used to create a complementary surface on the skate blade.
With time the profiling of ice skates has evolved as former recreational sports such as skating and “shinny” hockey evolved into Olympic sports with multiple disciplines including long-track speed skating, short-track speed skating, ice dance, ice etc and “shinny” hockey on frozen ponds, lakes, and rivers became a multi-billion dollar sporting franchise globally with individual players being remunerated in contracts of tens of millions of dollars. Alongside multiple equipment manufacturers jostle for an edge in the sports equipment market for the over 1.5 million registered hockey players globally and tens of millions of skaters globally who spend anything up to $1,000 on a pair of skates to keep up with their heroes, given the winning edge, etc.
As such ice skate blade profiles have evolved into a science with different profiles of blade between speed skating and ice dance, defender, goalie, attacker, short speed and long speed. Additionally atop these differences that science is establishing from research are the individualities of the various players and the intuitive, difficult to quantify “feel” of their skates.
Accordingly it would be desirable to provide an ice skate blade sharpening machine that allows for sharpening multiple blades simultaneously allowing accurate alignment of profiles for example within a single player's pair, across multiple pairs for a user or simply to reduce time and cost in retail establishments offering blade sharpening services.
It is an object of the present invention to obviate or mitigate at least one disadvantage of the prior art.
In accordance with an embodiment of the invention there is provided a method comprising:
In accordance with another embodiment of the invention there is provided a method comprising:
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:
Reference may be made below to specific elements, numbered in accordance with the attached figures. The discussion below should be taken to be exemplary in nature, and not as limiting of the scope of the present invention. The scope of the present invention is defined in the claims, and should not be considered as limited by the implementation details described below, which as one skilled in the art will appreciate, can be modified by replacing elements with equivalent functional elements.
Each of the ice skate sharpening systems above in
The geometry shown in CA 310 is with the circular arc centered with the blade, considered to be the best, arrangement and is known as “edges even condition”. The interrelation between the variables can be determined from Equations (1) and (2) below:
h
max
=r(1−cos(α sin(w/2r))) (1)
φ=90−α sin(w/2r) (2)
There are two other variables that can be changed in the above equations; namely, the width of the skate blade, w, and the radius of the groove, r. The width of the blade, w, is dependent upon the type of skating being done, with the typical hockey blade being 0.110 inches (2.8 mm) wide. The typical radius, r, used by hockey players varies from 0.250 (6.35 mm), such as shown by profile 340B for sharper turns but making gaining speed harder, to 2.00 (50.8 mm) inches, such as shown profile 340A making turns difficult. A common radius being 0.50 (6.35 mm) inches. Typical values of groove radius, r, when applied to hockey skates, 0.110 inches (2.8 mm) wide, will give the values of maximum depth, hmax, and the edge angle as shown below in Table 1.
It is worth noting that the range of edge angles, φ, and depths, h, is very limited. It is common knowledge in the ice skating world that a smaller radius provides better turning ability along with a slower glide speed, while a larger radius provides superior glide speeds along with poorer turning ability.
Now considering the FBC 320 then the cross-section through an ice skate blade is shown where a flat bottom has been added to the traditional circular arc profile, leaving the two interior circular arc profiles. In this case, the edge angle, φ, will remain the same as those calculated for circular arc profiles of various radii, r, as shown in Table 1 above but the depth of the flat, h, will be adjustable to any value less than the maximum depth, hmax, under the blade as calculated for the circular arc. The depth of the flat, h is the distance between a line joining the two blade edges, and the flat bottom of the skate blade. The width of the flat bottom, d, is given by Equation (3) below.
d=2[r2−(r−hmax+h)2]1/2 (3)
The advantage of this profile over the traditional circular arc profile is that the edge angle, φ, can be maintained while the depth, h, of the profile is reduced from, hmax, leading to a potentially faster skate with less drag. A nomenclature for FBC profiles used by some manufacturers is FBC-XXX-YY where XXX is the radius, r, of the arc in thousandths of an inch and YY is the depth of the flat, h, in thousandths of an inch.
Now referring to FBV 330 then this groove profile on an ice skate blade is an attempt to overcome the primary shortcoming of the traditional circular arc profile; the fact that the edge angle, φ, and the maximum depth of the groove, hmax, are linked. This is a major constraint of the CA 310 profile. This profile is named flat bottom ‘v’ (FBV) as the two lower internal profile lines would intersect in a V if there were projected, and the bottom of the ice skate blade forms a flat bottom for the V shape resulting from that projection. There are a few geometric properties that define the shape of the FBV 330 ice skate blade profile; the blade width, w, the width of the flat bottom, d, and the depth of the flat bottom, h. The height under the blade, h, is the distance between a line joining the two blade edges and the flat bottom. The edge angle, φ, at the blade edge, in the case of a symmetrical (central to the blade width) location of the blade bottom is given by Equation (4).
φ=α tan(w−d)/2h (4)
As can be seen from this formula; once a blade width, w, is known, a value of blade bottom width, d, can be chosen in conjunction with the depth of the flat, h, to obtain a wide range of edge angle, φ, values. A similar nomenclature as that for FBC 320 is used by some manufacturers, FBV-XXX-YY. The ability to vary the blade profile being shown by profiles 350A through 350D whereby moving from first profile 350A to second profile 350B are variations for constant bottom width, d, but varying depth of flat, h, giving better turns. Moving from first profile 350A to third profile 350C is decreasing bottom width, d, for constant depth of flat, h, giving more speed. Moving diagonally from first profile 350A to fourth profile 350D is decreasing bottom width, d, and increasing depth of flat, h, trying to balance speed and turning.
Now referring to
As can be seen in schematic 430 this offset 426 is even more critical as one moves from a freestyle blade of typical width 0.15″ (3.8 mm) to the narrower 0.11″ (2.8 mm) blade of an ice dance skate. Accordingly it would be evident how alignment of the blade is important not only within a single skate for desired edges but also within the pair. In some instances such as short-track speed skating where the skater is essentially permanently on one edge there may be introduced a deliberate offset 426 but again the control of this is important to achieve the desired edge for the skater.
Referring to
Considering the zones then the toe 512 generally is used for starts, acceleration, and final toe snap and may represent 1 second of a stride that this zone is in contact with the ice. The front 514 is primarily used for acceleration and ankle dekes and typically represents 1-3 second of stride movement. The middle 516 is used most for gliding, stopping, forward strides of several seconds, and provides balance and pivot point in motion. Finally the heel 518 is used in stop-turns, extension and backward pushes for backward skating as well as crossovers, direction changes and balance. Typically the toe 512 and heel 514 represent 20% of the blade length, the middle 516 60%, and the heel 518 20%.
Now referring to
According to one embodiment of the invention drive 670 may be manually adjusted, second stage 680 rigidly mounting the frame 685 to the base 630 and first stage 690 be manually controlled. According to another embodiment of the invention the first stage 690, second stage 680 and drive 670 may all be controlled through a central microprocessor to automate the process of grinding a desired profile thereby improving the reproducibility of the profile applied to the blade 610B. It would be evident to one skilled in the art that the programme may be varied allowing an operator to simply key in an identity of a skater for example to retrieve their custom profile and reapply this to the skates.
It would also be evident to one of skill in the art that in both manual and automatic approaches that a measurement and indication of pressure between the blade 610B and grinding wheel 650 may be made/displayed allowing increased control of the grinding process. Optionally if a conductive grinding wheel 650 is employed then an electrical contact may be made to both the grinding wheel 650 and blade 610B such that initial contact of the blade 610B to the grinding wheel 650 can be detected or monitored to detect errors in position as contact is lost for example.
Now referring to
The skate mount 700A provides for mounting of left skate 750A and right skate 750B with corresponding left blade 740A and right blade 740B with each being clamped via a levered mechanism engaged via first and second handles 760A and 760b respectively. Skate mount 700A further comprising skate stage 770. As with skate sharpening system 600 in
Referring to
An alternative approach is presented in second and third schematics 850A and 850B respectively wherein rather than a large grinding disc a small thin grinding element is employed. Accordingly as depicted in second schematic 850A the profiling is achieved through a combination of moving the grinding element 840 both along the length of the blade 830 and across the width. As such the small thin grinding element 840 in conjunction with automated stages such as presented supra in respect of skate sharpening system 700 in
Third schematic 850B depicts a FCA/FBV combination blade 890 along with first through third blades 860 to 880 respectively. These blades providing different grinding profiles which may be employed along with thin profile blade 840 alone or in combination with a skate sharpening system such as described supra in respect of skate sharpening systems 600, 700 and 900 in
Now referring to
The skate mount 900A provides for mounting of left skate 950A and right skate 950B with corresponding left blade 940A and right blade 940B with each being clamped via a levered mechanism engaged via first and second handles 960A and 960B respectively. Skate mount 900A further comprising skate stage 970. As with skate sharpening system 600 in
It would be evident to one skilled in the art that whilst the simplest design is the stacking of a pair of skate sharpening systems 600 to form skate sharpening system 900 that under appropriate computer control the relative motions of first and second grinders 900B and 900C may be controlled such that they operate without requiring a minimum complete clear separation between them such that the vertical height of the skate sharpening system 900 may be reduced. Accordingly skate sharpening system 900 can provide complex blade profiles to each of the left and right skates of a user with accurate cross-referencing of the profile of one blade to the other.
It would be evident to one skilled in the art that the ice skate blade may be formed from a variety of materials according to the cost, strength, weight, rigidity, and performance tradeoffs that the skate manufacturer is working within. Such blades may for example be formed from carbon steel, high strength low alloy steel, low alloy steel, stainless steel, as well as metals such as titanium. Alternatively blades may be formed from a variety of composite materials which are engineered materials that comprise two or more components including for example polymer composites that combine reinforcing fibers such as carbon fiber, glass fiber, basalt fibers, or other reinforcing fibers with a thermosetting or thermoplastic polymer resin such as epoxy, nylon, polyester, polypropylene, or other resins wherein the reinforcing fibers provide stiffness and strength in the direction of the fiber length, and the resin provides shape and toughness and transfers load between and among the fibers. Optionally, the blades may be formed from one or more ceramic materials including for example oxides such as alumina, beryllia, ceria, and zirconia; non-oxides such as carbides, borides, nitrides, and silicides; as well as ceramic composite materials including for example particulate reinforced, fiber reinforced, and combinations of oxides and non-oxides.
It would be evident to one skilled in the art that the discussions supra in respect of
The above-described embodiments of the present invention are intended to be examples only. Alterations, modifications and variations may be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.
This patent application claims the benefit of U.S. Provisional Patent Application US 61/409,650 filed Nov. 3, 2010 entitled “Ice Skate Blade” and U.S. Provisional Patent Application 61/409,650 filed Nov. 2, 2010 entitled “Multiple Blade Sharpening Apparatus and Method”
Number | Date | Country | |
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61409142 | Nov 2010 | US | |
61409650 | Nov 2010 | US |