Cutlery – Cutting tools – Plural cooperating blades
Reexamination Certificate
2001-06-01
2003-11-25
Payer, Hwei-Siu (Department: 3724)
Cutlery
Cutting tools
Plural cooperating blades
C030S233000, C030S131000
Reexamination Certificate
active
06651345
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an improvement of scissors for hair cutting or hairdressing such as cutting shears or thinning shears. In particular, the present invention relates to scissors in which, when the hair is cut or thinned, non-slip is applied so as to prevent hair from slipping at the edge of the blade of scissors in which such a non-slip effect is not degraded by sharpening of the scissors, naturally finished hair is obtained, and the improved cutting performance and abrasion resistance can be obtained.
BACKGROUND ART
When the hair is cut by cutting shears for hair cutting or hairdressing, as shown in
FIG. 34
, there occurs a phenomenon that hairs sandwiched between two blades
102
,
102
slip from the heel of the blades in the point direction. Thus, the hair cutting quantity is reduced by such slip.
In addition, when a cut trace is aligned transversely in a straight line, the hair cutting is not aligned in a predetermined transverse line. As shown in
FIG. 35
, the cut trace is curved, which is inconvenient.
In the case where the hair is aligned in a straight line by means of the cutting shears, the straight line of the cut trace stands out too much. Therefore, this straight line is shaded, whereby natural finish is sometimes done.
However, even in the case where such linearly cut trace is shaded, straight line alignment using the cutting shears is performed as preprocessing. Then, the hair aligned in this straight line is thinned, the cut trace is shaded, and natural finish is done. Therefore, two types of scissors, cutting shears and thinning shears are used, which is cumbersome. Moreover, in such preprocessing, i.e., straight line alignment using the cutting shears, the hair is hardly aligned in a straight line. Thus, the hair must be cut many times in order to align the hair in a straight line, which is cumbersome.
In order to eliminate this inconvenience relevant to this slippage, as shown in FIG.
36
,there is provided cutting shears
201
in which sectional V shaped or U shaped concave ridges
202
are continuously provided at the edge of the blade, whereby V shaped or U shaped waves are repeatedly provided to form a serrated blade shape. According to the scissors, hair is captured by concave ridges
202
of the blade, and does not slip. Thus, the problem with the above described slippage is eliminated.
The problem with hair slippage occurs with thinning shears similarly. The hair can be hardly thinned well because the hair slips while it slips at the edge of the thinning blade. In order to solve the above problem, as shown in FIG.
37
and
FIG. 38
, there are provided thinning shears in which V shaped or U shaped concave ridges
202
are provided at the edge of the thinning blade. According to the thinning shears, hair is captured by the concave ridges of the edge, and does not slip. Thus, the above described problem with hair slippage is eliminated.
In general, as scissors are repeatedly used, their cutting performance is degraded. Thus, the scissors are used while they are sharpened as required. Specifically, as indicated by alternate long and short dash lines in
FIG. 39
, a portion close to the edge of the blade is sharpened. However, sharpening such portion close to the edge of the blade shaves the concave ridges
202
formed at the edge, and. there disappear V shaped or U shaped concave ridges
202
shown in
FIG. 36
to FIG.
38
. In practice, the concave ridges
202
disappear, and a linear edge is obtained by performing such sharpening only one or two times. As a result, there is a problem that the hair that has not been slipped starts slipping.
In addition, in either of the cutting shears and the thinning shears as well, when the edge is formed in a V shape or U shape, the hair is captured by the concave ridges, thus forming a lock. Extra force is required when the scissors are closed to cut such locks. In addition, strong resistance is felt, and touch sense is impaired, which is not preferred in workability.
On the other hand, in general, scissors are often made of stainless having the hardness of about 650 Hv. The higher hardness improves the cutting performance more significantly. When in use, the excellent cutting performance is obtained, and strong wear and tear resistance is obtained. In general, the upper limit of the obtained hardness of stainless is about 800 Hv. As a material that exceeds this limit, there is provided a hard tool material of which the hardness of about 1000 Hv to 1500 Hv or about 2000 Hv can be obtained. However, the blade made of a material with the higher hardness becomes weaker, nicks in the edges are likely to occur. Thus, the edge angle is increased, thereby preventing such nicks in the edges. However, when the edge angle is increased in scissors, the blade hardly cuts into hair, and the hair easily slips. As a result, the slip of the, hair when the scissors are closed becomes significant, and the scissors do not function well. Therefore, scissors made of such material with the high hardness is not provided.
At present, scissors having the hardness of about 700 Hv are partially provided. This hardness is defined as the upper limit required to function as scissors in view of the presence or absence of slip. If the scissors are made of stainless having the hardness of 800 Hv, the cutting performance is improved. Further, if the scissors are made of a hard tool material with the ultra-high hardness, the cutting performance and wear and tear resistance is improved more significantly. On the other hand, there is a problem that the slip due to hair slippage becomes extremely significant, which is impractical. In particular, when the scissors are made of a hard tool material, the wear and tear resistance is expected to be about 10 times as high as conventional scissors. Although such scissors are ideal in cutting performance and wear and tear resistance, the hair slips more easily, which is impractical.
The objective of the present invention is to provide scissors in which non-slip is applied to the hair or such a non-slip state can be maintained irrespective of sharpening, a proper closing feeling is obtained, the feeling being free of strong resistance in scissors closing operation, and in particular, a required natural finished cut can be achieved in cutting shears, the scissors having excellent cutting performance and wear and tear resistance.
DISCLOSURE OF THE INVENTION
According to the present invention, there is provided scissors in which substantially linear slits or the like that cut out at the edge of a blade or blades are serially provided along the edge, and, by assuming a hair with predetermined thickness, a variety of slit widths of the slits are defined when the hair thickness is defined as a reference.
First, as shown in
FIG. 1
to
FIG. 3
, a slit is defined as a slit width that is equal to or smaller than the predetermined thickness of a hair. Namely, the width of the slit is provided to be smaller than or equal to the thickness of hair. The scissors may be cutting shears or thinning shears and any other shape.
In this manner, if the slit is smaller than the thickness of a hair, as shown in
FIG. 4
, hair X is caught by opening
4
of slit
3
, which functions as non-slip. In addition, the slit is equal to the thickness of the hair, the hair is caught similarly, which functions as non-slip. Alternatively, as shown in
FIG. 5
, one or two hairs X enter the slit, and are stuck in the slit. Namely, the hairs are clogged at the opening, which functions as non-slip for the hair.
Moreover, in these scissors, as indicated by alternate long and short dash lines in
FIG. 6
, even if the edge is sharpened and retracted, slit
3
is not eliminated as illustrated, and a non-slip effect continues to the end.
Although the above slits may be formed (manufactured) in any way, these slits can be formed as an example by grinding wheels with the thickness equal to the slit width of each of the slits. If a thin slit and a slit thicker than the slit are formed, two types of grinding wheels that corresp
Cohen Jerry
Payer Hwei-Siu
Perkins Smith & Cohen
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