HK1191900B - Scissors - Google Patents

Description

Scissors

Technical Field

The present invention relates to a pair of scissors for cutting various kinds of paper, adhesive tape, cloth, etc. in an office or a general home.

Technical Field

In addition to being sized and heavy to enable a woman or a child to easily use the scissors with one hand, it is desired that various kinds of paper, cloth, and the like can be easily cut by opening and closing the scissors with a finger.

Therefore, various proposals have been made to improve the cutting property and to easily open and close the blade portion with one finger. For example, as described in patent document 1, a ceramic coating layer is applied to the blade portion, or as described in patent document 2, various surface treatments such as providing a coating layer made of ultra-hard abrasive grains, or the like have been already put into practical use.

In order to prevent the object to be cut from being caught between the blades and thus being difficult to cut, there have been proposed a method of forming a space called "back slit" or "back recess" in the inner surface of the blade, or a method of forming the "back slit", etc. by improving the inner surface of the blade so as to form a gap between the inner surfaces of the two blades as disclosed in patent document 3 or patent document 4, and actually, some scissors have been carried out.

[ patent document 1 ]

Japanese patent laid-open No. H05-096065

[ patent document 2 ]

Japanese patent laid-open publication No. 2005-168625

[ patent document 3 ]

Japanese patent laid-open No. 2001-314669

[ patent document 4 ]

Japanese patent laid-open No. 2003-062362

Disclosure of Invention

Problems to be solved by the invention

Well known scissors are: when cutting an object such as thick paper, although a large force can be applied to the root of the cutting blade, the opening angle of the two blades increases, and the object to be cut moves from the root of the cutting blade toward the tip of the cutting blade as if it were escaping, and the object to be cut cannot be cut, and therefore the object to be cut cannot be cut with a small force in some cases.

The present invention has been made to overcome such drawbacks, and an object to be cut is easily cut in a stable state by using a portion from the root to the tip of a cutting blade.

Means for solving the problems

The scissors related by the invention are as follows: in a curved shape of cutting edges of scissors, the scissors are turned on, a distance between a crossing point where the left and right cutting edges cross and a rotation center is defined as Y, a connection line connecting the crossing point where the left and right cutting edges cross and the rotation center is defined as a rotation reference line B, a distance from the rotation center to a fixed point A on the left and right cutting edges of the scissors is defined as R (mm), an angle at which the fixed point A of one cutting edge crosses the rotation center and the rotation reference line B is defined as θ (rad), and an angle formed by connecting lines at the fixed points A of the left and right cutting edges with each other is defined as X (rad), and an equation on polar coordinates representing a shape of the cutting edges satisfies the following equation:

Ｒ＝Ｙ＊exp（θ＊Cot（Ｘ／2））。

here, the value of X is set to a range of pi/18 (rad) to pi/3 (rad), and the value of Y when the left and right cutting edges are opened maximally is set to a range of 5 (mm) to 30 (mm) in a state where the left and right cutting edges are staggered.

Further, the maximum value of the R of the scissors is 200 (mm).

Effects of the invention

The distance R from the center of rotation of the cutting edge to the fixed points A on the cutting edges on the left and right sides is specified by the intersection angle theta between the fixed point A on one cutting edge and the rotation reference line B formed by the center line of the opening scissors or the intersection angle X of the cutting edges on the left and right sides, and the equation on the polar coordinates representing the shape of the cutting edge satisfies the following formula:

Ｒ＝Ｙ＊exp（θ＊Cot（Ｘ／2））。

therefore, even when the scissors are opened widely or opened to a small extent, the crossing angle of the cutting blades is not changed, and a certain cutting feeling can be maintained and a good cutting can be performed from the base to the tip of the cutting blades.

Since the maximum value of the distance R to the cutting edge at the fixed point a is set to 200 (mm), the scissors can be generally used even by women or children.

Drawings

Fig. 1 is a front view showing a closed state of scissors for business use according to the present invention;

FIG. 2 is a front view showing a slightly opened state of the scissors for business use according to the present invention;

FIG. 3 is a front view showing an opened state of the scissors for business use of the present invention;

FIG. 4 is a side view showing a closed state of the scissors for business use according to the present invention;

FIG. 5 is a rear view showing a state in which blades of the scissors are overlapped in a collapsed state of the scissors for business use according to the present invention;

fig. 6 is a rear view showing a state in which blades overlap each other in a collapsed state in an embodiment in which the blade intersection angles of the scissors for business use of the present invention are different.

Detailed Description

As shown in fig. 1 and 2, the scissors according to the present invention have a curved cutting edge 27 formed on the blade body 21, and a base 25 of the blade body 21 has a receding portion 18 formed in a shape of: the end of the cutting blade 27 on the base 25 side is shaped to be further retracted than the side edge 16 of the connecting portion 15 connecting the shank 33 including the grip 35 and the blade portion 21.

In addition, the curved shape of the shearing blade 27 is not set to a constant curvature from the tip 23 to the base 25 of the blade 21, but the curvature of the shearing blade 27 is changed so that the radius of curvature of the base 25 side is gradually reduced, that is, the curvature of the base 25 side is gradually increased, compared with the tip 23 side in the left and right blade 21.

Further, the scissors 10 have a grip 35 for engaging a finger hole 37, which is integrated with the connecting portion 15 via the handle 33, and the connecting portion 15 has a screw as the coupling member 31, and the 1 st scissor body 41 and the 2 nd scissor body 42 are rotatably connected by the screw. Further, the 1 st scissor body 41 and the 2 nd scissor body 42 are respectively provided with an elongated plate-like blade body 21 extending from the connecting portion 15, and one side thereof is a cutting blade 27 and the other side thereof is a back 29.

The back 29 of the blade body 21 has: the blade 21 is connected from the front end 23 to the side edge 16 of the connecting portion 15 by a smooth curve having a large radius of curvature close to a straight line. Further, the blade portion 21 is: the shearing edge 27 is curved to widen the intermediate width between the leading end 23 and the base 25. The cutting blade 27 located at the base 25 of the blade unit 21 is set at a position retreated from the side edge 16 of the connecting portion 15, and the retreated portion 18 is formed at the base-side end of the cutting blade 27.

In this way, the shearing blade 27 has a curved shape in which the radius of curvature on the base 25 side is smaller than the radius of curvature on the tip 23 side of the blade unit 21, in other words, the curvature gradually increases from the tip 23 toward the base 25. The curvature is changed such that when the 1 st scissor body 41 and the 2 nd scissor body 42 are spread by opening the left and right blade body portions 21 to a predetermined width as shown in fig. 3, the distance between the intersection point where the left and right cutting edges 27 intersect with each other and the rotation center is Y, the connection line connecting the intersection point where the left and right cutting edges 27 intersect with the rotation center is a rotation reference line B, the distance from the rotation center of the scissors 10 to the fixed points A on the left and right cutting edges 27 is R (mm), the angle at which the connection line connecting the fixed point A of one cutting edge 27 and the rotation center intersects with the rotation reference line B is theta (rad), and an angle formed by connecting lines at the fixed points a of the cutting edges 27 on the left and right sides is x (rad), an equation on polar coordinates representing the shape of the cutting edges 27 satisfies the following equation:

Ｒ＝Ｙ＊exp（θ＊Cot（Ｘ／2））。

in this way, when the distance R from the rotation center to the specified fixed point a of the cutting blades 27 is set at the angle θ where the connection line connecting the fixed point a and the rotation center intersects the rotation reference line B and the angle X/2 where the connection line connecting the fixed point a and the rotation reference line B intersects the connection line of the fixed point a and the rotation reference line B, the cutting blades 27 of the 1 st scissor body 41 and the cutting blades 27 of the 2 nd scissor body 42 can be staggered at a position, and even if the base 25 of the blade body 21 changes to the tip 23, the staggered angle α of the cutting blades 27 can be maintained at a constant angle.

That is, as shown in fig. 2, regardless of the change in opening angle β between blade body 21 of first scissor body 41 and blade body 21 of second scissor body 42, the angle α at which cutting edge 27 of first scissor body 41 and cutting edge 27 of second scissor body 42 intersect can be maintained at a constant angle.

In addition, the value of X at the angle at which the connecting lines intersect at the fixed points a of the cutting edges 27 is set to be in the range of pi/18 (rad) to pi/3 (rad), and the value of Y, which is the distance from the rotation center at which the cutting edges 27 on the left and right sides are maximum to the position at which the cutting edges 27 intersect, that is, the distance Y from the rotation center to the end of the cutting edge 27 on the base portion 25 side, is set to be in the range of 5 (mm) to 30 (mm) in the state in which the left and right cutting edges 27 intersect.

When the value of the angle X at which the connecting lines intersect each other at the fixed points a of the two cutting edges 27 is set to be smaller than pi/18, the gap between the cutting edge portion 21 of the 1 st scissor body 41 and the cutting edge portion 21 of the 2 nd scissor body 42 when the cutting edge portion 21 of the scissors 10 is opened is reduced, and it becomes difficult to sandwich paper or cloth as a cutting object, which is not preferable.

When the value of the angle X at which the connecting lines intersect at the fixed point a of the cutting edges 27 is set to be large, the curvature of the cutting edges 27 increases. Therefore, when the length of the cutting edge 27 is constant and the value of the angle X is larger than pi/3 (rad), the distance between the back portion 29, which is located at the middle of the blade portion 21 and is formed to be the width of the blade portion 21, and the cutting edge 27 becomes large, and a peculiar shape which is different from the usual shape of the common scissors 10 and is formed to be the width of the blade portion 21 at the middle is formed, so that a sense of incongruity is generated, and the effect is not good.

Therefore, the temperature of the molten metal is controlled,will be provided withThe angle X at which the connecting lines cross each other at the fixed points A of the two shearing blades 27 is set to be in the range of pi/18 (rad) to pi/3 (rad), and more preferably in the range of pi/12 (rad) to pi/5 (rad).

In addition, when the value of the distance Y from the rotation center of the blade portion 21 to the end portion of the cutting edge 27 on the base portion 25 side is 5 (mm) or less, in the common scissors 10 for one-handed use, the connection portion 15 may be difficult to combine durability of the 1 st scissor body 41 and the 2 nd scissor body 42, and when it exceeds 30 (mm), the length of the cutting edge 27 becomes short, making it difficult to operate the scissors 10 for use.

Accordingly, in order to use the scissors 10 in a state where the scissors 10 are opened to the maximum extent by inserting a finger through the finger-fastening hole 37, it is preferable that the value of the distance Y from the rotation center of the blade portion 21 to the end of the cutting blade 27 on the base 25 side is set to about 5 (mm) to 15 (mm).

Further, the maximum distance (Rmax) from the rotation center to the tip 23 of the blade portion 21 is set to 200 (mm), so that the scissors 10 can be made to be large and small, and can be easily handled by women and children.

In the scissors 10 shown in fig. 2 and 3, when the cutting edges 27 intersect, the intersection angle of the cutting edges 27 is set to be pi/6 (rad).

By setting the crossing angle of the two cutting blades 27 to pi/6 (rad) degrees, the object to be cut can be easily cut by the depth of the blade unit 21.

That is, when the object to be cut is cut by the scissors 10, in order to combine the cutting action with the cutting action so that the object is cut, the cutting probability is higher as the intersection angle of the cutting blades 27 is smaller, and the cutting ratio is higher as the intersection angle of the cutting blades 27 is larger. When the crossing angle of the cutting edge 27 is about pi/6 (rad), the ratio between the cutting and the shearing action becomes substantially equal, and the object to be cut such as paper can be cut by the cutting edge 27 without escaping in the direction of the edge tip and biting the object, and the object to be cut can be cut by cutting with a small force and by performing the operation of the folding scissors 10.

In the scissors 10 of the present embodiment, the angle of intersection of the cutting edges 27 does not change from the base 25 to the tip 23, and therefore, even when the cutting is performed on the base 25 side of the blade unit 21 or the tip 23 of the blade unit 21, the shearing ratio for the shearing operation is not reduced, and the object to be sheared can be easily sheared by the shearing operation. Accordingly, the cutting blade 21 can be cut easily in a stable and constant state from the base 25 to the tip 23.

As shown in fig. 4 and 5, blade portions 21 of first scissors element 41 and second scissors element 42 have the same shape as blade portions 21 of first scissors element 41, and blade portions 21 having the same shape are symmetrical and are connected to each other by coupling member 31 in connection portion 15 so as to be rotatable with respect to each other. The blade 21 has a receding portion 18 between the base of the shear blade 27 and the side edge 16 of the connecting portion 15, and the back 29 of the blade 21 is formed in a shape smoothly continuous with the side edge 16 of the connecting portion 15. Further, when scissors 10 are closed, blade portions 21 in 1 st scissor body 41 and blade portions 21 in 2 nd scissor body 42 overlap such that cutting edges 27 in blade portions 21 of 2 nd scissor body 42 are located more inside than back portions 29 in blade portions 21 of 1 st scissor body 41, so that cutting edges 27 are not touched unintentionally.

In scissors 10 in which the angle X at which the connecting lines at the fixed points a of the two cutting edges 27 intersect each other is pi/7 (rad), as shown in fig. 6, the width of the blade portion 21 when the 1 st and 2 nd scissor bodies 41 and 42 are folded can be reduced by slightly reducing the bending angle of the cutting edges 27 with respect to the scissors 10 shown in fig. 5.

Further, the above embodiment is: first scissor body 41 and second scissor body 42 are rotatably integrated by screws as coupling members 31, but appropriate fixing means such as screws or rivets may be used as coupling members 31 so long as first scissor body 41 and second scissor body 42 can be rotatably connected to each other.

Further, the blade body 21 is coated with ceramic or titanium, or a back recess is formed in the back surface of the blade body 21, whereby the scissors 10 having the blade body 21 with a more excellent shearing feeling can be manufactured.

Possibility of industrial utilization

The present invention relates to a pair of business scissors 10, which comprises: the shearing blade 27 is curved so that the width of the middle portion of the blade portion 21 is the widest, the curved shape of the shearing blade 27 is changed so that the curvature gradually increases from the tip 23 toward the base 25, and the blade portion 21 on the base side of the blade portion 21 is set so as to recede from the side edge 16 of the connecting portion 15, whereby the object to be sheared can be easily sheared in a stable state using the distance from the base 25 to the tip 23 of the blade portion 21.

Description of the symbols

10 the connecting part of the scissors 15 is provided with a pair of scissors,

16 flank 18 receding portion

Front end of 21-blade cutter body 23

25 the base 27 of the cutting blade,

29 back 31 joining member

33 a grip portion of a handle portion 35,

37-button finger hole 41 1 st scissors body

42 nd 2 shear body

Claims (2)

1. A pair of scissors is characterized in that a pair of scissors blades are arranged in a scissors body,

in the curved shape of the cutting edges of the scissors,

when the scissors are opened, the distance between the staggered point where the cutting edges on the left and right sides are staggered and the rotation center is set as Y,

a rotation reference line B is set as a connection line connecting the intersection point where the left and right cutting blades intersect and the rotation center,

the distance from the center of rotation of the scissors to the fixed points A on the cutting edges on the left and right sides is set as Rmm,

the angle at which the connecting line connecting the fixed point A of the cutting edge on one side and the rotation center and the rotation reference line B intersect is set to theta rad,

the angle formed by the tangent lines of the left and right cutting edges at the fixed point A is set as Xrad,

the equation on the polar coordinates representing the shape of the cutting edge satisfies the following equation:

R＝Y＊exp(θ＊Cot(X/2))，

wherein the value of X is set in the range of pi/18 (rad) to pi/3 (rad)

The value of Y when the left and right cutting edges are opened to the maximum extent in a state where the left and right cutting edges are staggered is set in the range of 5mm to 30 mm.

2. The scissors of claim 1,

the maximum value of R is 200 mm.