Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO 94/21113 215 ~ 0 7 PCT/US93/02573
HORSESHOE
Description
Technical Field
The invention relates generally to the field of farriery and
more particularly to a horseshoe design for horses hooves which
enables the animal to move with a more natural motion of its
feet.
Background Art
As those skilled in the art, particularly farriers and
veterinarians, are aware domestic horses have for a great many
years been routinely shod with shoes the purpose of which was to
lengthen the stride of the animal to provide traction and prevent
concussion. Thus, it has been commonplace to lengthen the toe
in order to accomplish the longer stride, especially in race
horses . As a result horses were shod with long shoes and lowered
heels in the belief that this would decrease the concussion and
lengthen the stride. In point of fact research departments in
farrier science have found that the opposite may be true.
Studies indicate that lengthening the toe and dropping the heel
decrease the hoof angle, and that the old ways have been
contributing factors to hoof related problems such as bowed
tendons, ringbone, navicular disease, bucked shins and sesamoid
problems. The longer toe and shorter heel theory has been
thought to lower the arc of the foot s flight pattern. Again,
however, it has been found that it takes the hoof longer to break
over and delayed break over increases fatigue. It is to be kept
in mind that break over is the last phase of the stride prior to
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the hoof's leaving the ground. The end of the toe and the foot
rotate over losing traction with the ground and beginning the
next stride.
For race horses the desire has been to minimize stresses on
the leg structure including tendons and ligaments. Tendons
become pulled if the hoof comes off the ground unnaturally so
that the flexor tendons are stressed and the extensors in turn
are also stressed trying to compensate for the unnatural flexor
action. Another common problem is that of chipped knees caused
by unnatural break over placing excessive strain on the multiple
bone structure. The result can be and often is that corners of
the bones are chipped off. Because it is conventional and most
practical to fit a shoe to the most forward part of the hoof the
art of shoeing horses has perpetuated the practice of causing
unnatural foot action, and thus the excessive strain on the
tendon system and secondary stress on the bone structure.
Among the prior art references are the following United
States Patent numbers 90,394; 100,328; 155,362; 180,980; 421,349;
483,537; 507,276; 591,166; 562,567; 764,950; 804,839; 980,655;
998,196; 3,460,637; 3,794,120; 3,311,174; 2,791,280; 3,159,220;
4,333,532; 4,721,165. See also HORSESHOEING THEORY AND HOOF
CARE, Leslie Emery, Jim Miller, Nyles Van Hoosen, 1977, Lea &
Febiger, Philadelphia. The only horseshoe of those shown in the
prior art and identified above is the structure disclosed in No.
4,721,165 by applicant herein. The referenced patent, however,
does not teach a shoe which places the calk or grab plate forward
of a line substantially directly under the tip of the coffin
bone.
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WO 94/21113 PCTrC1S93/02573
Disclosure of the znventiun
The invention is a h~::ax~sesrroe havinrx a clc>se<i end or
toe portion which is formed to extend transversely or
laterally across the front and urrdex~ t:he hoof rat:hern than
being rounded to the shape of the toe o.f the hoof. A grab
plate is shaped to e~~t.er~ld ac:rcass t:h:~e. t,~~:: from ju;~t forward
of a li~.c, extending .-,~.:~: t ~rGt,a..a~1'X' ~ ~=. ew?:.=laa dov~~m
i~rcrrv, the
t ip of t he cof fir; borne oaf the hcac.~f t o another l ute about
thirty degrees forward nzE=_,_z~~:~x.:i.mc~ :C:r~mu the cofi=in bone tip.
The toe is formed so that the inside edge of the toe
portion angles downwar~dl.y and fox°wardly and th.e front edge
of the toe angles downwarc~:l.y and rearwardly so that there
is no inclination fon ttve sfzoe t-:c:~ r.~rag ca x: interfere through
the horse' s stride . ~,he shoe ~.s al. so formed so tr:zat the
branches conform to a natural pattern of wear in unshod
horses . The heel is slight::.l,y prcar~ouzaced so that. f:or racing
horses the grab plate is slightly more pronounced or even
with the heel becausE:~ c~f t:.:he :soft: rri.aterial of x~ac;e tracks.
For more conventional. saddle horse ~~zsas~e the shoe is of
about equal ueig~ut bcatil Lzorit arid buck. :Lt is contemplated
that: the heels cc,..ild be hi.c~inei: t:rm~rz t~z~} grafa plate on the
toe.
Accordingly i.t is among t:he features and adi~antages of
tr~is invention to prc:vide a horseshoe design that. conforms
to the natural wear pattern oa: a tacarse' ~ rzooi.. Tide toe is
formed substantially s~~.r.a~.~ht ac,xos:~ sco that the Arab plate
is located, when the shoe is installed on a horse's foot,
forwardly of the tip of the horse' s c.:aaf in bone in a zone
defined between a line extending substantially directly
down from the tip of the c:~offi.n bone axed a line extending
outward from the coffin bone tip at. an
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angle of thirty degrees with the angle being determined from the
tip of the coffin bone. The design permits the horse to employ
its most natural leg and hoof action, a natural and unimpeded
break over so that stresses on the tendons and bone structure are
minimized. Since the stresses are minimized the muscular
structure becomes less easily fatigued. The shoe's design
enables a limited amount of rotation when the shoe is fitted to
a particular horse so that the shoe is square with or conforms
with the angle in which the knee flexes. Thus, the horse does
not have to favor an unbalanced hoof-knee action and lose any
power in its stride. This shoe will allow the horse to move over
the toe of its foot in a manner that is most natural for it.
Brief Description of the Drawings
Figure 1 is an illustrative view of the outline structure
of a horse's lower leg and hoof showing the location of the
coffin bone with the hoof and the position of the shoe of this
invention with respect to the coffin bone;
Figure 2 is a bottom plan view of the shoe of this invention
showing details of its configuration and construction;
Figure 3 is a partial cross section view taken along the
line 3-3 of Fig. 2 showing the shape of the toe section;
Figure 4 is a cross section view taken along the line 4-4
of Fig. 2 and further illustrating details of the design;
Figure 5 is perspective view of the insert grab plate;
Figure 6 is a bottom plan view of the shoe of this invention
as it would appear in relation to the frog when mounted to a
horse's foot, the shoe embodiment having a straight toe and a
straight grab plate; and
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Figure 7 is a bottom plan view of the shoe of this invention
as it would appear in relation to the frog when mounted to a
horse's foot, the shoe embodiment having a flattened, but still
curved, toe and a slightly curved grab plate.
Best Mode For Carrying Out the Invention
The history and development of today's horses show that in
the wild where they live successfully, as for instance in the
arid regions of the American west, the hoof shape and health
depend on the specific environment and lifestyle therein.
Significantly, the finest quality horn composition and least
amount of deformity in hooves occurs in these wild animals. As
the horse developed the task of flexing the leg fell primarily
to the deep digital flexor tendon and at the same time the
importance of the navicular bone increased since it functions as
a pulley or brace for the deep digital flexor tendon. Many of
the guidelines for shoeing horses have come from the form the
hoof assumes when the animal runs wild.
When a naturally shaped hoof is placed on a level surface
the ground surfaces of the hoof walls are well rounded,
especially at the toe where the most friction occurs. The hoof
wall at the toe usually appears short and the heels generally
strong and wide. The front hooves exhibit this condition to a
much greater degree than the hind feet. Hooves shaped under such
conditions rarely have pointed toes or sharp edged walls. Thus,
a degree of upward concavity is seen across the toe between the
quarters and along both branches between toe and heel.
Regardless of environment, whether it is wet or arv ~,- a
combination of both, the rotation point of a hoof varies from a
WO 94/21113 PCT/US93/02573
215303
point just forward of a line extending directly down from the tip
of the coffin bone to up to thirty degrees forward thereof. The
angle of thirty degrees forwardly is defined from the tip of the
coffin bone.
What has been discovered is that the break over point for
domestic horses undergoes a transition from a point forward of
a line extending generally directly downward from the tip of the
cof f in bone .
Referring now to the drawings it will be seen that Figs. 1
and 6 show the lower portion of a horse's leg in general outline
to illustrate the principle of the instant invention. Within leg
L and hoof H is the coffin bone C at the bottom of a column of
leg bones to which the hoof is attached. For optimum action the
hoof must break over as near the center of the toe as possible.
To enable such break over the coffin bone C is round or arcuate
in shape to provide support on the sides. The wider form of a
front hoof provides a greater area of support for the heavier
weight borne by the front leg and also tends to prevent break
over to the side. The rear hooves on the other hand have
straighter sides and allow lateral break over. The tip T of the
coffin bone is, as stated above, generally arcuate across the
front. The sole of a horse's foot contains the frog F which
serves to cushion the foot during impact.
Figures 1, 6 and 7 illustrate the placement of the shoe with
respect to the center of the foot CF and the foot front and rear
bearing points. The shoe branches are widest across from the
center of the foot CF and the cross-over lines CL1 and CL2 that
extend between the diagonally-opposite front and rear bearing
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21 530 73
points, designated FBP and RBP respectively, show the placement of
the grab plate 70 relative to the front bearing line FBL that
extends transversely between the front bearing points FBP, FBP.
For a straight-toed shoe with a straight grab plate as shown in
Figure 6, the grab plate lies on the front bearing line FBL and
extends from one bearing point FBP to the other bearing point FBP.
For a flattened, but rounded, toed shoe with a slightly curved grab
plate as shown in Figure 7, the grab plate extends from one bearing
point FBP to the other bearing point FBP, and the curvature of the
grab plate lies slightly forward of the front bearing line FBL. In
the Figure 7 shoe, the toe of the shoe, although slightly curved,
is flattened sufficiently that the toe is broad enough so that the
front bearing points FBP, FBP are located where the curvature of
the toe transitions in the curvature of the shoe branches. Also,
with respect to the Figure 7 shoe, the front bearing points FBP,
FBP and the corners (or ends) of the grab plate 70 must be lowered
slightly with respect to the rest of the grab plate to the extent
that the front bearing points FBP, FBP are extended at least 1/16
inch below the center of the grab plate, and may be .extended up to
1/4 inch beyond the grab plate center.
The four bearing points FPL, FBP, RBP and RBP, at the medial
and lateral toe and at the medial and lateral heel, are located by
the crossed lines CL1 and CL2 that extend through the center of the
foot. CL and intersect the foot edges at the natural bearing points
of the foot. The front bearing points at the toe indicate where
breakover should occur. The crossed lines CLl and CL2 extend
diagonally between medial heel and lateral toe and
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WO 94/21113 PCT/US93/02573
between lateral heel and medial toe; the cross over point CF
lying between about 3/8-3/4 inch posterior to the apex of the
frog. The shoe of Figure 6 and the shoe of Figure 7 are designed
so that the ends of the grab plate 70 lie on the front bearing
points and dictate the location of the break over line FBL with
respect to the foot. Thus, if a particular foot has been
deformed through poor farrier practices or for some other reason,
the application of the shoe of this invention will locate the
shoe of this invention with respect to the center of the foot CL
and not with respect to the toe of the foot. This will place the
grab plate 70 of the foot within the region A shown in Figure 1.
A horse's hind foot must articulate medially and laterally
and it would likely be the case that a Figure 7-type shoe would
be employed rather that a Figure 1-type shoe. However, it may
be the case also that the Figure 1-type shoe could be employed
for a front foot.
Figures 1 through 7 illustrate the principles and details
of the invention. Shoe 10 has toe portion 12, branches 14 and
16 , and heel portions 18 and 2 0 at the ends of the branches . The
shoe is provided with fullering grooves 22 and 24 as in
conventional shoes and nail holes 26 and 28 with the fullering
grooves 22 and 24.
Toe portion 12 of the Figures 2-6 shoe extends straight, as
shown, across the front of the hoof so that the front edge 30 is
recessed under the toe of the hoof (by as much as a quarter to
as much as half an inch). The top surface 32 of the shoe which
contacts the bottom of the hoof is essentially a flat planar
surface. Front edge 30 angles rearwardly and downwardly to
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define front sloping surface 34 which extends across
substantially the entire toe section of the shoe. Front surface
34 terminates as at lines 36 and 38 at its ends and along a line
40 at the lower edge of said slope. An inside sloped surface 42
angles downwardly and forwardly from rear toe edge 31. A lower
edge 44 is spaced from edge 40. Between edges 40 and 44 is an
insert or grab plate cavity 46 extending a predetermined depth
up into the toe of the shoe. Preferably the angle of inside
sloping surface 42 is about 50 to 53 degrees as indicated by the
drawings though such angle may vary between about 45 to 55
degrees. The angle of 50 to 53 degrees will be recognized to
represent the hoof angle in the average horse. The angle of
inside surface 42 of the toe portion is included because it
conforms to the angle of the cof f in bone and because the grab
plate tends to maintain its traction through a greater degree of
hoof rotation.
The branches 14 and 16 of the shoe have sloping inside
surfaces 50 and 52 which coincide with toe inside surface 42 and
extend rearwardly to the heel portions 18 and 20. Ridge edges
54 and 56 extend from the grab plate cavity to the heel area and
as can be seen in Fig. 3 the ridge edges are higher through the
quarter part of the branches than near the toe or heel portions.
Again, as pointed out in the general discussion of natural hoof
wear, the hoof through the quarter part tends to be slightly
upwardly rounded or concave. Thus, the ridge edges are shaped
to reflect this natural wear pattern. At the heel portion of
each branch the heel has rearwardly and downwardly extending
contact surfaces 60 and 62 which raise the heel portions 18 and
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WO 94/21113 ~ ~ ~ ~ ~ '3 PCT/US93/02573
20. The extreme rear of each heel has rear edge 64 or 66. It
will- be appreciated that the fullering grooves 22 and 24 are
recessed with respect to the ridge edges 54 and 56 as is best
illustrated in Fig. 4. The body of show 10 is preferably made
of aluminum, but could be made of plastic or other metal as
desired such as titanium, steel, etc.
The insert or grab plate, generally designated by the number
70, is a steel or other hard, well-wearing material shaped as
shown. The shoe body can, if desired, be made integrally with
the grab plate so that a separate insert is not necessary. The
insert is basically rectangular to be received in cavity 46 of
the toe of the shoe except for the outer edge which contacts or
grips the ground. Thus, it is provided with an outer edge 74
which is shaped to coincide with the line 40 at the lower edge
of sloping surface 34 of the shoe toe, and ends 78 and 80. Note
that the ends of the grab plate are bent at an angle to the rear
to conform to the curvature of the shoe body itself. Thus, the
cavity 46 as well as the ends of the grab plate are shaped
accordingly. The outer edge 74 may extend substantially above
the lower edge line 40, depending upon the use to which the shoe
is to be put. The insert grab plate shown is a racing style,
part of which is slightly higher than the heel of the shoe. For
saddle and other types of horses the grab plate and heel will be
approximately the same height.
This toe insert, or grab plate, is of a much harder material
from that from which the shoe is made. This grab plate is
embedded into the shoe at the time of the forging. If necessary
or desired, the grab plate may be slightly tapered outwardly, or
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WO 94/21113 PCT/US93/02573
otherwise so formed, as it extends into the shoe. Thus, when the
shoe is forged the shoe metal will be filled around the grab
plate and fixedly secure the grab plate in place.
In accordance with the principles of this invention, the
shoe is mounted to a horse's foot such that the grab plate 70 is
located within a zone forward of the tip T of the coffin bone.
This zone is defined by the angle A which is between a first line
extending vertically downward from the tip T of the coffin bone
and a second line extending downward and forward from the tip T
of the coffin bone to bound angle A. This angle A is 30°. The
shoe would not be mounted such that the straight edge 74 of grab
plate 70 would be located beyond 30°, nor directly under the tip
T of the coffin bone. As a guide to positioning the shoe to
conform with these principles, the shoe would be located such
that the straight edge 74 of grab plate 70 would be located
between about 1 and 1-1/2 inches forwardly of the tip TF of the
frog F; identified as distance D in Figures 1 and 7. Horseshoes
are categorized by shoe sizes; #4 being the smallest and #8 being
the largest for saddle horses. The preferred range for setting
a horseshoe with respect to the frog tip TF in relation to shoe
size is shown in the following Table.
TABLE
Shoe Size Shoe Length Shoe Width Distance (D~~ from TF
#4 4-1/4" 4-1/2" 1~~
4-1/2" 4-3/4" 1-1/8"
6 4-3/4" 5" 1-1/4"
7 5" 5-1/4n 1-3/8n
8 5-1/4" 5-1/2" 1-1/2"
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PCT/US93102573
W094/21113 ~1~3~~J
As shown in Figure 7, the inside surfaces 42, 50, 52 of the shoe
toe and branches may be provided with positioning marks; such as
line 100 for centering the shoe with respect to the frog tip TF,
and lines 102, 104 for forwardly-positioning the shoe with respect
to the frog tip TF. These lines, actually positioning marks, can
be forged into the shoe and appear as narrow ribs slightly raised
beyond the shoe's inside surfaces or as narrow grooves slightly
depressed into the shoe's inside surface. Each shoe size would
be marked according to its size so as to insure placement of the
shoe's grab plate 70 in accordance with the Table.
The straight outer edge 74 or the grab plate 70 becomes the
breakover point for the horse's foot. If that breakover point
is located with respect to the coffin bone tip T in accordance
with the principles of this invention as related in the Table,
the action of the foot during breakover will more closely
replicate the natural foot breakover as experienced by a wild
horse. The domestic horse's foot, under the influence of the
shoe of this invention, will gradually reform itself more toward
the natural foot structure evidenced by wild horses. The use of
the shoe of this invention, therefore, has a therapeutic effect
in aiding the domestic horse's foot to restructure itself more
closely to the natural ideal. As the domestic horse's foot
restructures itself, there will come a time when the shoe, as it
is periodically reset, may be positioned with the grab plate 70
located nearer the coffin bone tip T. Therefore, the Table
identifies distances D that are approximately the maximum for
each given shoe size.
The Figure 7 shoe is identical with the Figures 2-6 shoe
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__ 215373 ~CTIUS93 ~/ X2573
46 R~~'~ ~~':'°...°'T--. 2 4 AP 81995
excepting that the toe of the shoe is rounded and the grab plate is
rounded as shown. All other relationships are as described with
respect to Figures 2-6. The mid-point of the grab plate 70 of the
Figure 7 shoe must be higher than the elevation of the front
bearing points FBP, FBP to insure that these points accurately and
actually define the breakover line FBL for the shod foot. The
distance D between the tip of the frog TF and the breakover line
FBL is the same and the same considerations apply as discussed with
respect to the Figures 2-6 shoe. In the Figure 7 shoe, the front
bearing points are located at the points where the radius of the
shoe changes from the curvature of the flattened curve toe to the
curvature of the branches.
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