Skate sharpening mechanism

A mechanism for the sharpening of skate blades comprising a small cylindrical honing stone or similar device, supported and located by two rollers which are caused to rotate, thus rotating the stone as this slides back and forth along the concavity of the blade. This results in sharpening the edges and forming a concavity of a suitable radius. A means of tilting the stone to maintain this tangent to the curvature of the blade, is also achieved such that the total cylindrical surface of the cutting (honing) stone is utilized.

BACKGROUND 
1. Field of Invention 
This invention relates to ice skating blades, specifically to an improved 
method of sharpening. 
2. Description of Prior Art 
Skate blades used for ice hockey, figure, free style and dance, etc., are 
made from hardened and tempered steel having sharp inside and outside 
edges separated by a concavity. With use, these edges become dull and the 
concavity which supports the skater's weight, loses its smoothness and 
shape thus degrading the performance of the skater. 
Heretofore it was common practice to restore these edges and the concavity 
using a grinding machine designed for this purpose. Such machines 
generally utilize a flat disc-shaped grinding wheel mounted on a vertical 
shaft, rotating at high speed. This in turn is mounted to a flat steel 
table such that the grinding wheel is several inches above the surface of 
the table. To grind the concavity, a suitable radius for each type of 
skate must be formed on the rim of the grinding wheel using a radius 
forming tool. The skating blade with boot attached is clamped on its side 
to a steel block which slides easily in any direction over the table 
surface. The center line of the skate blade runs parallel with the surface 
of the table and the grinding wheel is adjusted to a suitable level to 
match the center line of the blade. 
Using a continuous sweeping motion, the operator then moves the skate blade 
against the grinding wheel, thus restoring the concavity and sharpening 
both edges. Some machines have two stations so that a medium grit and a 
fine grit grinding wheel are available. Other machines use similar 
grinding methods. 
New skate blades are manufactured with very specific curvatures to enable a 
skater to perform intricate maneuvers on the ice. Undulations and change 
of curvature of the skate blade will occur with each resharpening. 
Operator skill and experience is critical in attempting to minimize these 
distortions. 
On some machines a template may be used to restore the curvature. However, 
this method is seldom used since a template for each size and type of 
skate blade is required. Also a considerable amount of metal removal is 
often necessary to restore the original curvature. 
To grind the concavity a suitable radius for each type of skate must be 
formed on the edge of the grinding wheel using a special diamond tool. 
During the sharpening operation the grinding wheel, rotating at high speed, 
heats the skate blade. This in turn permanently softens the edges being 
sharpened resulting in the need for more frequent regrinds since softened 
edges become blunt more rapidly than hardened edges with use. Such heating 
could be avoided using a cutting fluid, however skate grinding machines 
are designed to operate "dry". 
Some disadvantages of the above method of sharpening skate blades are 
listed below: 
OPERATOR SKILL REQUIRED. The operator must have a high degree of skill in 
attempting to maintain an even pressure and steady traverse without bounce 
while pressing the skate blade against the spinning grinding wheel. 
DISTORTION. Regardless of operator skill, undulations and curvature 
distortions do occur, this being cumulative with future regrinding. 
HIGH COST. Different blades require different concavity radii. An expensive 
diamond tool is used to form whichever radius is needed on the edge of the 
grinding wheel. During use, further dressing of the grinding wheel becomes 
necessary due to loading and glazing thus reducing the grinding wheel 
diameter to the point where frequent replacements become necessary. 
SOFTENS EDGES. Grinding without using cutting fluid causes severe heating, 
particularly at the edges of the blade. This results in softening of these 
hardened steel edges which now blunt rapidly with use, leading to more 
frequent resharpenings. 
ROUGH SURFACE FINISH. A polished surface on the concavity of the blade is 
desirable for low skating friction (the total weight of the skater is 
concentrated on a very small area of this surface). However when using a 
fine grit or polishing wheel without the use of cutting fluid, severe 
softening of the edges will occur. Hence a relatively coarse finish 
instead of a mirror finish must be tolerated. 
DIFFICULTY IN CHANGING GRINDING WHEEL RADIUS. The correct concavity radius 
must be formed on the grinding wheel using a radius fixture with a diamond 
tool. This procedure is time consuming requiring expertise. The fixture 
containing the diamond tool must be adjusted to the required radius prior 
to shaping the grinding wheel. It is not practical to have a set of 
grinding wheels each with a different peripheral radius since the wheel, 
when mounted, will not run precisely true, hence the need to be 
recontoured after mounting. 
LACK OF PORTABILITY. Most machines are too heavy and cumbersome to 
transport easily (e.g. in the trunk of a car). 
DEGRADATION OF SKATING ABILITY. Skaters usually delay sharpening until a 
regrind is absolutely necessary since a potential setback in skating 
performance is anticipated due to the change in curvature as a result of 
sharpening. 
SKATING BLADE REPLACEMENT. By design the skate blade has a specific 
curvature. Towards the front the curvature becomes tighter (the rocker). 
This transition is used by the skater to execute 3-turns, counters, etc., 
and when flattened due to regrinding, the skater must compromise her 
ability with an increased danger of accident. Also excessive loss of metal 
often occurs at the heel end of the skate blade posing a danger to the 
skater of falling backwards. A common solution is the purchase of new 
blades. 
PROTECTIVE EQUIPMENT REQUIRED. When grinding skate blades, the operator 
must wear both goggles and breathing mask to protect him from high 
velocity metal particles and the inhalation of metal dust. 
OBJECTS AND ADVANTAGES 
Most enthusiastic skaters would find it desirable to own a skate sharpening 
machine having none of the above disadvantages. Accordingly these problems 
are eliminated with my invention whose objects and advantages are: 
SKILL NOT REQUIRED. The method and mechanism described below forms the 
basis for a machine which can be used by an unskilled operator. Once the 
skates are clamped on to the machine, the stone inserted, and the machine 
started, the sharpening process is entirely automatic. Heretofore the 
operator required training and expertise in sliding the fixture 
horizontally to touch the skate blade against the rotating grinding wheel, 
at the same time traversing the blade along its length while attempting to 
avoid undulations and uneven metal removal. 
RETENTION OF CURVATURE. Using this invention the removal of metal will be 
relatively constant over the length of the blade thus distortion of the 
curvature will be minimized. Heretofore distortion of the blade was 
inevitable and cumulative since no mechanical means of control was used. 
LOWER COST. Honing stones suitable for use with this invention are less 
expensive than grinding wheels. 
AVAILABILITY. Cylindrical honing stones have been used by tool and die 
makers for decades and consequently are readily available in a range of 
grit sizes and diameters. 
LOW SKATING FRICTION. After sharpening the skate blades the concavity can 
be polished by inserting a fine grit or polishing stone (e.g. Arkansas 
stone). This enables the skater to glide over the ice with less effort, 
improving performance. Heretofore this fine polishing was difficult, if 
not impossible to achieve. 
RETENTION OF SHARPNESS. Using my invention, there is no softening of the 
skate blade edges since this is a cold wet process. In contrast, the dry 
grinding process causes severe heating and softening of the factory 
hardened edges which blunt more rapidly with use. 
EASE OF CHANGING CONCAVITY RADIUS. By inserting a different diameter stone 
the concavity radius is readily altered within a wide range of radii. Also 
the polishing stone might be slightly larger or smaller in diameter than 
the relatively coarse honing stone previously used for sharpening, yet 
alignment will be maintained and no adjustment to the machine will be 
necessary. Heretofore the concavity radius had to be formed on the 
grinding wheel using a radius fixture with a diamond tool. This procedure 
is time consuming and requires expertise since the fixture containing the 
diamond tool must be adjusted to the required radius and the grinding 
wheel is diminished on each reshaping. 
VERSATILITY. Different stones such as coarse, medium and fine India stones 
can be used with my invention. Also diamond coated cylinders or the 
lapping process using a brass cylinder and rouge or any similar abrasive 
system are all compatible with this invention. 
PORTABILITY. The machine is a portable unit not unlike a home sewing 
machine, which can readily be placed in the trunk of a car. Most existing 
skate sharpeners are heavy and cumbersome. 
SKATING PROFICIENCY. Maintaining curvature and sharpness of the skate blade 
aids the skater's performance. With this invention touch-ups are fast and 
easy, thus enhancing the skater's opportunity for improvement. Skaters 
usually delay sharpening until a regrind by a skilled expert is absolutely 
necessary since the trauma of readjustment to a resharpened blade often 
results in a setback in skating prowess. This invention is ideally suited 
for use by any skater intent on keeping her skates in perfect condition. 
STONE LOADING & GLAZING PROBLEMS ALLEVIATED. Loading or clogging of the 
honing stone with metal cuttings is minimized since the honing stone 
reverses after each stroke along the length of the blade concavity. Also a 
fresh cutting surface is continually presented as the stone rotates. In 
addition the honing fluid lubricates the cutting action and the heating 
problems do not occur. Glazing of the stone is also minimized since no 
heating takes place. 
STONE SHAPE RETENTION. The use of this mechanism ensures that stone wear is 
relatively even, thus roundness is maintained. Also the total cylindrical 
surface of the stone is used in a relatively regular pattern as this tilts 
to follow the curvature of the blade using the entire stone length. 
SAFETY & CLEANLINESS. Protective equipment is unnecessary since this is a 
clean and easy method of sharpening skates. Any metal particles are 
captured by the small amount of honing fluid used and my invention is 
quiet and clean. 
Further objects and advantages of my invention will become apparent from a 
consideration of the ensuing description and the accompanying drawings.

DESCRIPTION OF INVENTION 
FIG. 1 shows a skating blade 1, having an inside and an outside edge 2 and 
3, with a concavity 4 between. The cylindrical honing stone 5 is aligned 
centrally between the edges 2 and 3, and rests on the concavity surface 4. 
Rollers 6 and 7, are positioned to locate and align the stone 5, central 
to the inner and outer edges 2 and 3 of the blade 1. 
A U-shaped frame 13 supports the rollers 6 and 7, such that the gap formed 
by the legs of the U-frame 13 is slightly larger than the length of the 
stone, while the longer rollers 6 and 7, are supported by free fitting 
holes or bearings. This U-frame 13 is rigidly fixed to an arm 18, such 
that adjustment of the angle between the arm 18 and U-frame 13 is 
possible. 
Rollers 6 and 7, have similar gear wheels 8 and 9 fixed to one end and 
these gears 8 and 9, are meshed into a central gear 10, with a ratcheting 
or turning attachment 11 and 12. 
FIG. 2 shows the arm 18, pivoted on a shaft 15, fixed to the sliding 
carriage 16 of the skate sharpening machine. This arm 18, supports the 
U-frame assembly 14. Torque is applied to this arm 18 by a coil spring 19. 
OPERATION OF INVENTION 
The following disclosure describes a mechanism using a cylindrical honing 
stone 5, or similar abrasive device to hone the skate blade 1, thus 
correcting the concavity radius 4, and sharpening both edges 2 and 3. A 
stone diameter relating to blade width, style of skating and the skater's 
preference, is selected (i.e. hockey blades require a smaller radius 
concavity than free style blades). To maintain roundness and reduce 
loading of the stone 5, the mechanism herein described provides for 
rotation of this stone 5, by using two rollers 6 and 7. FIG. 1, whose 
longitudinal axes are parallel with that of the stone 5. These support and 
align the stone 5, relative to the center line of the skate blade 
concavity 4, being honed. By causing the rollers 6 and 7, to rotate 
incrementally while the stone 5, is sliding along the concavity, the 
rotation of the stone 5, is assured, since the friction between the stone 
and the surface being honed is low relative to the rolling friction 
between the honing stone 5, and the rollers 6 and 7. 
This method of supporting and locating the stone 5, permits similar size 
stones having a wide range of grit sizes to be easily inserted for any 
desired result. A wide range of stone diameters may be used while 
maintaining the alignment between the center line of the stone 5, and 
blade 1. 
Also the cylindrical honing device will not wear in discrete segments since 
the rotation is indexed in a non-repetitive manner. 
It is advantageous to utilize the total cylindrical surface of the honing 
stone 5. This disclosure includes a method whereby this is achieved. To 
understand the mechanism involved, a description of one of several 
configurations follows: 
The skate blade 1, with or without the boot attached, is clamped upside 
down to a fixed frame. The U-frame assembly 14 is mounted at the end of an 
arm 18 which pivots on a shaft 15. This shaft 15 is rigidly attached to a 
carriage 16 which moves back and forth horizontally on guide rails. These 
rails run parallel with the center line of the skate blade 1. The shaft 15 
is arranged to project horizontally and at right angles to the guide rails 
17. As the honing stone 5 moves forward, the arm 18 will fall, thereby 
tilting the stone 5 to maintain a tangential contact between the stone 5 
and the curvature of the blade 1. The total change in angle (or tilt) 
which takes place during a complete stroke, can be decreased or increased 
by raising or lowering the forward end of the blade 1 relative to its heel 
end. With this adjustment, the entire length of the honing stone 5 may be 
used during a complete stroke or traverse. Another unique feature is that 
the abrasive device hones a longer path than the carriage movement (see 
FIG. 2). This is advantageous in designing a compact skate sharpening 
machine. As a result of this tilting motion combined with the rotation of 
the stone 5, the total cylindrical abrasive surface of the stone is used. 
In the above text the honing stone 5 is described as moving back and forth 
while in operation. However, this disclosure covers all configurations 
using similar geometry, for example, traversing can be other than 
horizontal. Also the skate blade may be clamped to the moving carriage 
while the arm and honing stone assembly 14, can be mounted to the frame, 
thus achieving a similar result. 
Since the honing stone assembly 14 has an up/down motion during each stroke 
(FIG. 2) this movement can be utilized to rotate the rollers 6 and 7. 
Electrical or other means may also be used. The method indicated here 
employs a ratchet (FIG. 1) with the pawl 12 mounted on a lever 11 This 
lever 11 is positioned to strike a finger mounted on the carriage 16, 
while the up/down motion is taking place. The rollers 6 and 7 are 
mechanically coupled using three gear wheel 8, 9 and 10, meshed together 
and rotated by the engagement of the pawl 12 as the lever drops. 
It is desirable to maintain a steady load at the area of contact between 
the cylindrical honing stone 5 and the concavity 4 of the skate blade so 
that the rate of metal removal is roughly constant over the length of the 
blade 1, during honing. One method uses a spring 19 with one end attached 
to the arm 18 and the other end fixed to the frame, thus as the carriage 
16 moves forward, the spring 19 will stretch, increasing the torque 
exerted on the arm 18. This action may be used to advantage since the 
contact area between the honing stone 5 and the concavity 4 also moves 
forward at the same time, thus requiring an increase in torque to maintain 
a steady load. By suitable spring design and orientation, a close 
compromise is achieved to maintain a relatively uniform load at this point 
of contact. 
CONCLUSION & SCOPE OF INVENTION 
Thus it will be seen that this skate sharpening mechanism provides a 
unique, reliable, precise, and clean method of sharpening skating blades 
with minimum distortion. A machine incorporating this mechanism can be 
used by skaters of almost any age as a convenient means of maintaining 
sharp edges and precise blade curvature, thus leading to more rapid 
improvement of skating ability. 
While the above description contains many specifics, these should not be 
construed as limitations on the scope of the invention but rather as an 
example of one embodiment. Other variations are possible. Accordingly, the 
scope of the invention should be determined not by the embodiments 
illustrated but by the appended claims and their legal equivalents.