Golf ball

In a golf ball having a large number of dimples formed on the surface thereof, the dimples comprise circular dimples 2 and oval dimples 3 in flat configurations thereof. The total of the oval dimples is set to more than 20% of the total of the dimples. All the dimples are arranged in such a manner that an average intersection acute angle .delta. made between a line connecting the center of each oval dimple and a pole of the golf ball with each other and a major axis of each oval dimple is set in a range of 0.ltoreq..delta..ltoreq.80.degree..

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a golf ball, and more particularly to a 
golf ball having dimples, the surface configuration of which are improved 
to make the flow of air in the periphery thereof turbulent when it is 
flying in the air, so as to allow the golf ball to have a superior 
aerodynamic symmetrical property and allow it to fly a long distance, 
although one great circle path unintersecting with a seam line is present 
on the golf ball. 
2. Description of the Prior Art 
Normally, 280-540 dimples are formed on the surface of the golf ball. The 
role of the dimple is to make the flow of air in the periphery thereof 
turbulent when the golf ball is flying in the air so as to accelerate the 
transition of turbulent flows present in a boundary layer. That is, the 
role of the dimple is to reduce pressure resistance by shifting a 
separation point rearward and improve dynamic lift by increasing the 
pressure difference between the portion above the separation point and the 
portion below the separation point. Therefore, the dimple capable of 
making the flow of the air in the periphery of the golf ball turbulent is 
aerodynamically superior. 
Golf balls having dimples, formed on its surface, capable of effectively 
making the air in the periphery thereof turbulent have been proposed in 
view of the role of the dimple. For example, as disclosed in (1) Laid-Open 
Japanese Patent Publication No. 62-79072, a golf ball on which circular 
dimples of two different diameters are formed; and as disclosed in (2) 
Laid-Open Japanese Patent Publication No. 62192181, a golf ball on which 
dimples of a plurality of diameters are arranged densely. 
If a plurality of great circle paths, unintersecting with dimples, is 
formed on the surface of the golf ball, there is an increase in the area 
of a land, namely, a region in which dimples are not formed. Thus, the 
turbulence of air cannot be increased sufficiently. In view of this, the 
present applicant proposed a golf ball which was disclosed in Laid-Open 
Japanese Patent Publication No. 04-150875. According to the disclosure, 
dimples arranged regularly in divisions of a spherical surface formed by 
geometrically projecting a regular polyhedron thereon are re-arranged by 
shifting them not to allow the presence of great circle paths, and dimples 
positioned on the seam line corresponding to the face of contact between a 
pair of molding dies are shifted upward or downward or eliminated so that 
only one great circle path is present on the surface of the golf ball on 
the seam. 
The flow of air in the periphery of the golf ball becomes turbulent and the 
flight distance thereof is increased when dimples of different diameters 
are arranged densely in combination as disclosed in the above (1) and (2), 
further when only one great circle path unintersecting with dimples is 
present on the seam line, as disclosed in Laid-Open Japanese Patent 
Publication No. 04-150875. 
But because the great circle path unintersecting with dimples is present on 
the seam line, the conventional golf balls are not sufficient in 
displaying a favorable aerodynamic symmetrical property. That is, the 
flight distance of the golf ball is varied according to a hitting 
position. 
That is, referring to FIG. 1A, due to the presence of a great circle path 
(S) unintersecting with dimples, the flight distance of the golf ball in 
pole hitting is different from that in seam hitting. Seam hitting means a 
way of hitting the golf ball such that a line connecting both poles (P,P) 
with each other serves as a rotation axis L1 in back spin, as shown in 
FIG. 1(A), while pole hitting means a way of hitting the golf ball such 
that a line perpendicular to the rotation axis L1 serves as a rotation 
axis L2, as shown in FIG. 1(B). 
A golf ball having a great difference in the flight distance thereof 
depending on a rotational axis is not approved as an official golf ball. 
Needless to say, the golf ball is required to be approved as an official 
golf ball. In addition, the golf ball is demanded to have a difference 
smaller than the officially approved reference value in its flight 
distance and a favorable aerodynamic symmetrical property, regardless of 
rotation axes. 
SUMMARY OF THE INVENTION 
It is accordingly an object of the present invention to provide a golf ball 
having the same flight characteristic in both seam hitting and pole 
hitting, the direction of which is perpendicular to that of seam hitting; 
having a difference between the flight distance in seam hitting and in 
pole hitting in not more than the officially approved reference value; 
having the same trajectory in seam hitting and in pole hitting; having a 
superior aerodynamic symmetrical property in seam hitting and in pole 
hitting; and having an increased flight distance. 
As a result of researches made by the inventors based on experiments, the 
inventors have found that dimples, of which the plan view are oval, have a 
great influence on the aerodynamic characteristic of a golf ball. Based on 
the experimental result, they have devised a golf ball by forming oval 
dimples on the surface thereof in combination with circular dimples and 
devised a method of arranging oval and circular dimples in combination to 
allow the flow of air in the periphery of the golf ball to be turbulent. 
Therefore, even though a great circle path unintersecting with dimples is 
present on the seam line, the golf ball can be allowed to have a much 
smaller difference in the flight distance in seam hitting and pole hitting 
and have a longer flight distance than conventional golf balls. 
More specifically, as defined in claim 1, in a golf ball having a large 
number of dimples formed on the surface thereof, the dimples comprise 
circular dimples and uncircular, namely, oval dimples in plan view 
thereof; the total of the oval dimples is set to more than 20% of the 
total of the dimples; and the oval dimples are arranged in such a manner 
that an average intersection acute angle .delta. made between a line 
connecting the center of each oval dimple and a pole of the golf ball with 
each other and the major axis line of each oval dimple is set in a range 
of 0.ltoreq..delta..ltoreq.80.degree.. 
As shown in FIG. 2, the intersection acute angle .delta. means an angle 
made between the line (L) connecting the center (O) of each oval dimple 3 
and a pole (P) of the golf ball with each other and the major axis (X) of 
each oval dimple, namely, the longest axis of axes passing through the 
center (O) of the oval dimple 3. The intersection acute angle .delta. is 
set in a range of 0.ltoreq..delta..ltoreq.90.degree.. The average angle 
.delta. is obtained by dividing the total of the angles .delta. of all 
oval dimples by the total of the oval dimples. 
As defined in claim 1, favorably, the average acute angle .delta. of the 
oval dimple is set in a range of 0.ltoreq..delta..ltoreq.80.degree. and 
more favorably, in a range of 0.ltoreq..delta..ltoreq.40.degree.. 
The oval dimple defined in claim 2 has the major axis (X) and the minor 
axis (Y) both passing through the center (O) thereof, and includes an 
elliptical dimple and an oval dimple defined a narrow sense. The oval 
dimple in a narrow sense are formed by connecting two circles arranged at 
a certain interval with each other with two common tangents. The ratio of 
the length of the major axis, of the oval dimple, passing through its 
center to the length of its minor axis passing through its center is set 
in a range of 1.2 to 3.5. 
As defined in claim 3, the total of the oval dimples is set to more than 
20% of the total of the dimples. The oval dimples consist of the ones in a 
narrow sense, the elliptical dimples or a combination of the oval dimples 
in a narrow sense and the elliptical dimples. 
As defined in claim 4, the golf ball has only one great circle path, 
unintersecting with the dimples, formed on the surface thereof. 
In the golf ball according to the present invention, the oval dimples 
allowing the air in the periphery of the golf ball to be greatly turbulent 
are formed on the surface thereof in combination with circular dimples in 
such a manner that the total of the oval dimples is set to more than 20% 
of the total of the dimples. Therefore, the dimples of the golf ball are 
capable of making the air in the periphery thereof more turbulent and 
flying it a longer distance than conventional golf balls. 
Further, as the oval dimples are arranged in such a manner that the 
intersection acute angle .delta. is set in a range of 
0.ltoreq..delta..ltoreq.80.degree., even though a great circle path 
unintersecting with dimples is present on the seam line, the dimples make 
the air in the periphery of the golf ball more turbulent than conventional 
dimples. Therefore, based on the inventors' experimental result, the 
flight distance and the trajectory between seam hitting and pole hitting, 
of the golf ball according to claim 2 have a smaller difference that the 
conventional golf ball. 
Based on the inventors' experimental result, the configuration of the oval 
dimple is set in such a manner that the ratio of the length of its major 
axis to the length of its minor axis is set in a range of 1.2 to 3.5, as 
defined in claim 2. The oval dimple having such a configuration is capable 
of making the flow of the air in the periphery of the golf ball more 
turbulent than the conventional dimples. If the configuration of the oval 
dimple is set in such a manner that the ratio of the length of its major 
axis to the length of its minor axis is set in a range of less than 1.2, 
the oval dimple having such a configuration is incapable of allowing the 
golf ball to have a favorable aerodynamic characteristic. If the 
configuration of the oval dimple is set in such a manner that the ratio of 
the length of its major axis to the length of its minor axis is set in a 
range of more than 3.5, the oval dimple having such a configuration 
increases a difference between directionality in the major axis and that 
in the minor axis. As a result, the golf ball has a particular 
directionality. Thus, preferably, the ratio is set in the range of 1.2 to 
3.5. 
As defined in claim 3, the oval dimples set to more than 20% of the total 
of the dimples consist of the oval dimples in a narrow sense, the 
elliptical dimples or a combination of the oval dimples in a narrow sense 
and the elliptical dimples. The oval dimples allow the golf ball to fly a 
longer distance and the favorable aerodynamic symmetrical property thereof 
to be superior. 
As defined in claim 4, it is preferable to reduce the number of great 
circle paths unintersecting with dimples to a possible smallest number, 
namely, to the one present on the seam line so as to arrange dimples 
densely, namely, reduce the area of a land on the surface of the golf 
ball. The dimples thus arranged on the surface of the golf ball allows the 
flow of air in the periphery thereof to be more turbulent and the golf 
ball to be flied a longer distance than the conventional golf ball.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A golf ball according to the present invention is described below with 
reference to drawings. 
Table 1 shows the dimple specification of golf balls of first through third 
embodiments of the present invention and that of golf balls of first and 
second comparison examples. FIGS. 6 through 8 show the golf balls of the 
first through third embodiments. FIGS. 9 and 10 show the golf balls of the 
first and second comparison examples. In FIGS. 6 through 10, a pole is 
positioned at the center of each golf ball, and a circumference 1 of each 
golf ball indicates the seam line. White dimples shown in FIGS. 6 through 
10 are circular dimples 2, and black dimples shown in FIGS. 6 through 10 
are oval dimples 3 in a narrow sense. As shown in Table 1, the total of 
dimples (total of all circular dimples 2 and all oval dimples 3) formed on 
each golf ball is 400. 
TABLE 1 
__________________________________________________________________________ 
(4) 
(6) 
(1) (2) 
(3) 
(5) 
D1 D2 L (7) (8) 
(9) 
(10) 
__________________________________________________________________________ 
A, 
88 4.1 
Emb. 1 
B 40 400 
3.7 
C 40 3.2 560 50% 
28.3 
mm.sup.3 
D 32 2.8 
FIG. 6 
E 80 -- 3.2 
3.2 
1.3 1.41 
F 120 -- 2.8 
2.8 
1.7 1.61 
A 72 4.1 
Emb. 2 
B 160 
400 
3.7 
C 48 3.2 560 22% 
28.0 
D 32 2.8 
FIG. 7 
E 32 -- 3.2 
3.2 
1.3 1.41 
F 56 -- 2.8 
2.8 
1.7 1.61 
A 80 4.1 
Emb. 3 
B 152 
400 
3.7 
C 48 3.2 560 22% 
79.4 
D 32 2.8 
FIG. 8 
E 32 -- 3.2 
3.2 
1.3 1.41 
F 56 -- 2.8 
2.8 
1.7 1.61 
A 80 4.1 
Com. 1 
B 152 
400 
3.7 
C 48 3.2 560 22% 
90.0 
D 32 2.8 
FIG. 9 
E 32 -- 3.2 
3.2 
1.3 1.41 
F 56 -- 2.8 
2.8 
1.7 1.61 
A 200 4.05 
Com. 2 
B 64 400 
3.90 
C 96 3.60 560 0% 
-- 
D 40 2.80 
FIG. 10 
E -- -- -- -- -- 
F -- -- -- -- -- 
__________________________________________________________________________ 
(1) denote kind of dimple 
(2) denote number of dimples 
(3) denote total of dimples 
(4) denote circular dimple 
(5) denote diameter 
(6) denote specificaton 
(7) denote total volume of dimple 
(8) denote (2)/(3) .times. 100 
(9) denote average .delta. angle of oval dimple 
(10) denote major axis/minor axis 
In the Table 1, Emb 1, Emb 2, and Emb 3 denote first embodiment, second 
embodiment, and third embodiment, respectively; and Com.1 and Com.2 denote 
first comparison example and second comparison example, respectively. 
In Table 1, the diameter of each circular dimple 2 is the distance between 
both points A and B of contact between a common tangent to a golf ball at 
left and right edges thereof. 
As shown in FIGS. 2 and 4, the oval dimple 3 is formed by connecting two 
circles C.sub.1 and C.sub.2 spaced at a certain interval with two common 
tangents. Reference symbols D1 and D2 in Table 1 denote the diameter of 
each of the circles C.sub.1 and C.sub.2. Reference symbol Z in FIG. 4 
denotes the length of each of the common tangents to the circles C.sub.1 
and C.sub.2. 
Referring to FIG. 5, the volume of the circular dimple 2 and that of the 
oval dimple 3 are the volume of a portion, shown with oblique lines, 
surrounded with an imaginary spherical line of the golf ball and the 
surface of each dimple. The total dimple volume shown in Table 1 is the 
total of the volumes of all dimples formed on the golf ball. The total 
volume of dimples to be formed on the golf balls of the embodiments and 
those of the comparison examples is set to 560 mm.sup.3. 
An average angle .delta. of the oval dimple shown in Table 1 is the average 
of intersection angles made between a major axis (X) of each oval dimple 
of FIG. 2 and a line (L) connecting the center (O) thereof and a pole (P) 
of the golf ball with each other. Table 1 also shows the ratio of the 
length of the major axis (X) to the length of the minor axis (Y) 
intersecting therewith at a right angle at the center (O) of the oval 
dimple 2. 
As shown in FIG. 6, the golf ball of the first embodiment has the circular 
dimples 2 and the oval dimples 3 formed on the surface thereof. One great 
circle path not intersecting with the circular dimples 2 and the oval 
dimples 3 is formed on the seam line shown by the circumference 1. The 
total of the oval dimples 3 is 200 which is set to 50% of the total of the 
dimples formed on the golf ball. The dimples are arranged in such a manner 
that the average angle .delta. of the oval dimples 3 is 28.3.degree.. The 
ratio of the length of the major axis (X) to the length of the minor axis 
(Y) is set to 1.2 to 3.5. More specifically, the above ratio is set to 
1.41 in the case of a dimple (E) and 1.61 in the case of a dimple (F). 
As shown in FIG. 7, the golf ball of the second embodiment has the circular 
dimples 2 and the oval dimples 3 formed on the surface thereof. One great 
circle path not intersecting with the circular dimples 2 and the oval 
dimples 3 is formed on the seam line shown by the circumference 1. The 
total of the oval dimples 3 is 88 which is 22% of the total of the dimples 
formed on the golf ball. The dimples are arranged in such a manner that 
the average angle .delta. of the oval dimple 3 is 28.degree.. Similarly to 
the first embodiment, the ratio of the length of the major axis (X) to the 
length of the minor axis (Y) is set to 1.41 in the case of the dimple (E) 
and 1.61 in the case of the dimple (F). 
As shown in FIG. 8, the golf ball of the third embodiment has the circular 
dimples 2 and the oval dimples 3 formed on the surface thereof. One great 
circle path not intersecting with the circular dimples 2 and the oval 
dimples 3 is formed on the seam line shown by the circumference 1. 
Similarly to the second embodiment, the total of the oval dimples 3 is 88 
which is 22% of the total of the dimples formed on the golf ball. The 
dimples are arranged in such a manner that the average angle .delta. of 
the oval dimple 3 is 79.4.degree. The ratio of the length of the major 
axis (X) to the length of the minor axis (Y) is set to 1.41 in the case of 
the dimple (E) and 1.61 in the case of the dimple (F), similarly to the 
first and second embodiments. 
As shown in FIG. 9, the golf ball of the first comparison example has the 
circular dimples 2 and the oval dimples 3 formed on the surface thereof. 
One great circle path not intersecting with the circular dimples 2 and the 
oval dimples 3 is formed on the seam line shown by the circumference 1. 
The total of the oval dimples 3 is 88 which is 22% of the total of the 
dimples formed on the golf ball, similarly to the second and third 
embodiments. The dimples are arranged in such a manner that the average 
angle .delta. of the oval dimple 3 is 90.degree.. The ratio of the length 
of the major axis (X) to the length of the minor axis (Y) is set to 1.41 
in the case of the dimple (E) and 1.61 in the case of the dimple (F), 
similarly to the first through third embodiments. 
As shown in FIG. 10, the golf ball of the second comparison example has 
only the circular dimples 2 formed thereon. Including the one present on 
the seam line 1, the golf ball has three great circle paths, not 
intersecting with the oval dimples 2, formed on the surface thereof. 
Each of the golf balls of the first through third embodiments and the golf 
balls of first and second comparison examples has a double construction, 
i.e., each golf ball comprises a core, the inner diameter of which is 
about 38.4 mm and a cover. That is, the golf ball is a two-piece ball. The 
outer diameter of the golf ball is 42.75.+-.0.05 mm and the compression 
thereof is 95.+-.3. 
In manufacturing the two-piece golf ball, materials are mixed with each 
other according to a mixing ratio shown in Table 2, and a mixture is 
kneaded by using an internal mixer to form a cylindrical plug. The plug is 
put into a pressurizing/heating molding die to vulcanize it at 150.degree. 
C. for 40 minutes to form a core having a diameter of 38.4 mm. The mixture 
of Surlyn 1707 (manufactured by Mitsui Dupon Polychemical Product Corp.) 
and titanium oxide mixed at a ratio of 100:2 is molded by injection, with 
the core covered with the mixture to form a golf ball having an outer 
diameter of 42.75 mm. Then, burr formed on the seam line is removed from 
the golf ball, and the surface thereof is painted. 
TABLE 2 
______________________________________ 
Material Parts by weight 
______________________________________ 
Polybutadiene 100 
Zinc acrylate 34 
Zinc oxide 17 
Dicumyl peroxide 
1.0 
oxide 
______________________________________ 
Comparison experiments were conducted on golf balls on which dimples were 
formed based on the specification of the first through third embodiments 
and that of the first and second comparison examples. 
The golf balls having the dimple specification shown in Table 1 were hit by 
a driver (W#1) at a head speed 48.9 m/s by using a swing robot 
manufactured by True Temper Corp. Wind was fair and almost windless, 
namely, 0.1-0.3 m/s. 48 golf balls were prepared for each of the first 
through third embodiments and the first and second comparison examples. 24 
golf balls were hit by pole hitting and seam hitting, respectively. 
Carries, flight times, and angles of elevation were measured for each golf 
ball. 
The carry is the distance from a ball-hit position to a ball-drop position. 
The flight time is a time period from a point when the golf ball is hit to 
a point when it has dropped on the ground. The angle of elevation is an 
angle formed between a horizontal line and a line connecting the hit 
position and the highest point of trajectory with each other. 
Table 3 shows results of measurements made in the experiment. 
TABLE 3 
______________________________________ 
Flight 
Carry time Elevation 
(yds) (sec) angle (.degree.) 
______________________________________ 
Emb 1 Pole hitting 252.5 7.08 12.75 
Seam hitting 252.3 7.04 12.73 
Remainder (Pole-Seam) 
0.2 0.04 0.02 
Emb 2 Pole hitting 251.4 7.03 12.69 
Seam hitting 250.7 6.96 12.63 
Remainder (Pole-Seam) 
0.7 0.07 0.06 
Emb 3 Pole hitting 250.8 6.98 12.66 
Seam Hitting 249.3 6.91 12.53 
Remainder (Pole-Seam) 
1.5 0.09 0.13 
Com. 1 Pole hitting 249.1 6.91 12.60 
Seam hitting 246.6 6.75 12.27 
Remainder (Pole-Seam) 
2.5 0.16 0.33 
Com. 2 Pole hitting 247.8 6.82 12.46 
Seam hitting 245.7 6.70 12.21 
Remainder (Pole-Seam) 
2.1 0.12 0.25 
______________________________________ 
In the Table 3, Emb 1, Emb 2, and Emb 3 denote first embodiment, second 
embodiment, and third embodiment, respectively; and Com.1 and Com.2 denote 
first comparison example and second comparison example, respectively. 
As shown in Table 3, the experimental results indicate the following 
points: 
As described previously, the golf balls of the first embodiment have the 
following dimple specification: The total of the oval dimples 3 is set to 
50% of the total of the dimples formed on the golf ball. The average angle 
.delta. of the oval dimple 3 is 28.3.degree.. The ratio of the length of 
the major axis (X) to the length of the minor axis (Y) is set to 1.41 and 
1.61 which are in the preferable range from 1.2 to 3.5.In the golf balls, 
the average of the angles of elevation in trajectory measured in pole 
hitting and seam hitting was 12.74.degree. which was highest of all the 
averages of the angles of elevation of the five kinds of golf balls; and 
the average of the carries measured in pole hitting and seam hitting was 
252.5 yards which was longest of all the averages of the carries of the 
five kinds of golf balls. The symmetrical property of the golf balls was 
superior: The difference in the carry, the flight time, and the angle of 
elevation between pole hitting and seam hitting were 0.2 yards, 0.04 
seconds, and 0.02.degree., respectively. 
As described previously, the golf balls of the second embodiment have the 
following dimple specification: The total of the oval dimples 3 is set to 
22% of the total of the dimples formed on the golf ball. The average angle 
.delta. of the oval dimple 3 is 28.0.degree.. The ratio of the length of 
the major axis (X) to the length of the minor axis (Y) is set to 1.41 and 
1.61 which is in the preferable range from 1.2 to 3.5. In the golf balls, 
the average of the angles of elevation in trajectory measured in pole 
hitting and seam hitting was 12.66.degree.; and the average of the carries 
was 251.1 yards which was comparatively long. The symmetrical property of 
the golf balls was also superior: The difference in the carry, the flight 
time, and the angle of elevation between pole hitting and seam hitting was 
0.7 yards; 0.07 seconds; and 0.06.degree., respectively. 
As described previously, the golf balls of the third embodiment have the 
following dimple specification: The total of the oval dimples 3 is set to 
22% of the total of the dimples formed on the golf ball. The average angle 
.delta. of the oval dimple 3 is 79.4.degree.. The ratio of the length of 
the major axis (X) to the length of the minor axis (Y) is set to 1.41 and 
1.61 which is in the preferable range from 1.2 to 3.5. In the golf balls, 
the average of the angles of elevation in trajectory was 12.60.degree.; 
and the average of the carries was 250.1 yards which was the third longest 
of the five kinds of the golf balls. The symmetrical property of the golf 
balls was also preferable: The difference in the carry, the flight time, 
and the angle of elevation between pole hitting and seam hitting was 1.5 
yards; 0.09 seconds; and 0.13.degree., respectively. 
As described previously, the golf balls of the first comparison example 
have the following dimple specification: The total of the oval dimples 3 
is set to 22% of the total of the dimples formed on the golf ball. The 
ratio of the length of the major axis (X) to the length of the minor axis 
(Y) is set to 1.41 and 1.61 which is in the range from 1.2 to 3.5 which is 
in the range of the present invention. The average angle .delta. of the 
oval dimple 3 is 90.degree. which is out of the range of the present 
invention. In the golf balls, the average of the angles of elevation in 
trajectory was 12.44.degree. ; and the average of the carries was 248.3 
yards which was fairly long, however, the symmetrical property thereof was 
worst of the five kinds of the golf balls: The difference in the carry, 
the flight time, and the angle of elevation between pole hitting and seam 
hitting was 2.5 yards; 0.16 seconds; and 0.33.degree., respectively. 
In the golf balls of the second comparison example having only the circular 
dimples 2, the average of the angles of elevation in trajectory was 
12.34.degree.; and the average of the carries was 246.8 yards. That is, 
the average of the angles of elevation in trajectory and the average of 
the carries were smaller than those of the golf ball of the first 
comparison example. The symmetrical property of the golf balls of the 
second comparison example was better than that of the first comparison 
example, but was less favorable than that of the first through third 
embodiments: The difference in the carry, the flight time, and the angle 
of elevation between pole hitting and seam hitting was 2.1 yards; 0.12 
seconds; and 0.25.degree., respectively. 
Although the present invention has been fully described in connection with 
the preferred embodiments thereof with reference to the accompanying 
drawings, it is to be noted that various changes and modifications are 
apparent to those skilled in the art. Such changes and modifications are 
to be understood as included within the scope of the present invention as 
defined by the appended claims unless they depart therefrom.