JPH0910449A - Cutting tool - Google Patents

Abstract

PURPOSE: To provide a cutting tool which can always cut like a new tool in such a manner that each of base lever and a driven lever is constructed by a lever main body and an edge plate, the edge plate is replaceably fixed to the lever main body, and only the edge plate is replaced. CONSTITUTION: When a cutting tool Tc is constructed, edge plates 4, 34 are overlapped with the inside of ends of lever main bodies 2, 32 and are fastened and fixed to the lever main bodies 2, 32 with fixing bolts 48, 49. Level differences 5, 35 each having a predetermined width are formed between edges 4a and 34a provided for the edge plates 4, 34 and the peripheries of the lever main bodies 2, 32. A cut part of a work W is put on the level differences in order to be recessed. Meanwhile, the ends of the fixing bolts 48, 49 penetrate the edge plates 4, 34 and are projected toward the inside. A projecting part 48a of the fixing bolt 48 on the base lever side is come into contact with the lever main body 32 of a driven lever 31 with a predetermined opening, thereby regulating the opening operation of the lever main body 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool used for manually cutting cables and the like.

[0002]

2. Description of the Related Art Conventionally, as cutting tools used for cutting cables and the like, two cutting tools which are pivotally attached to each other have been used.
Generally known is a so-called pliers type in which a blade portion is formed on each tip side of a book lever member, and the other end sides of these two lever members are grip portions facing each other. Has been.

Further, the applicant of the present invention utilizes the principle of the double lever in the cutting tool of the above-mentioned type, thereby significantly increasing the power increasing rate as compared with the conventional one without increasing the size of the tool, and the blade portion. Has been developed with a booster mechanism that can give a powerful cutting force (J.
879). Here, the power increase rate means the ratio (magnification) of the cutting force generated in the blade portion to the operation force applied to the grip portion of the cutting tool.

Further, the applicant of the present invention has filed patent No. 147690.
No. 2 proposes a boosting mechanism capable of achieving a dramatically higher magnification (higher infinity in principle) than the conventional one, and in Japanese Patent No. 1791035, the same action as above. We have proposed a method using a link mechanism of Section 4 without sliding friction. According to such a booster mechanism, as will be described in detail later, an extremely high power increase rate can be obtained, and the moving speed on the output side is made as slow as possible in the pressurizing process for the work, while being relatively low in the non-pressurizing process. Can be fast.

Furthermore, the applicant of the present application pays attention to the speed change characteristic on the output side in the above-mentioned booster mechanism.
In No. 28, such a booster mechanism was adopted as a cutting mechanism for manually cutting an optical fiber cable, and a concrete one as an optical fiber cable cutter was proposed. By adopting such a cutting mechanism, while keeping the stroke speed of the input side (that is, the drive lever) substantially constant,
The cutting speed is changed so that it is relatively high at the beginning of the cutting process and relatively low at the end of the cutting process, so that the soft part around the optical fiber cable and the core part with high hardness can be smoothly smoothed. It becomes possible to disconnect.

That is, in the above optical fiber cable, a core material (for example, a titanium alloy wire) having a predetermined strength and rigidity is usually passed through the shaft core, and an optical fiber is arranged around the core material, and then these are covered. It is supplied as a cable material formed by covering it with a material, but when this optical fiber cable is manually cut during wiring work, etc., the hardness of the core material of the cable and the surrounding area are significantly different. In addition, the cutting ability and workability of the conventional cutting tool are significantly deteriorated. In other words, in order to smoothly cut a material having a soft portion around a core material portion having a high hardness such as an optical fiber cable, the surrounding soft portion is quickly cut with a relatively small force, and a core material portion having a high hardness is cut. , It is required to cut slowly with a large force commensurate with its hardness and strength,
With a conventional cutting tool, it is basically impossible to change the cutting force or the cutting speed while keeping the stroke speed on the operating side (that is, the drive lever) substantially constant during cutting work. However, it is difficult to secure cutting performance and workability.

For example, in the case of a conventional ordinary pliers-shaped cutting tool, since the simple lever principle is used as it is, the power increase rate during the cutting operation of the tool is always constant. To change this boost rate, change the tool handle
The only way to change the lever ratio is to change the distance from the rotation fulcrum of the (lever member) to the blade or the grip (that is, the length of the lever member). Therefore, it is, of course, impossible to change this power increase rate during the cutting operation. Then, when trying to cut the optical fiber cable with such a tool, in order to cut the core material without trouble, the length of the lever member is set longer according to the hardness of the core material, and the power increase factor is set. It is better to increase the cutting force, but if you set the boosting factor of the cutting tool according to the hardness of the core material in this way, the cutting force generated at the blade will exceed the appropriate range for soft parts other than the core part. It becomes too big and it is difficult to cut both parts smoothly.

On the other hand, in the case of a cutting tool having a power boosting mechanism utilizing the above-mentioned double lever principle, the power boosting factor can be considerably increased, so that even if the cutting force is set to a large value, the lever member becomes long. Although it can be suppressed, even in this case, the multiplication factor of the cutting force is constant throughout the cutting work and cannot be changed basically.Therefore, when cutting the optical fiber cable, the soft parts around After all, it is difficult to smoothly cut the core material with high hardness.

On the other hand, in the case of the optical fiber cable cutter which employs the above-mentioned four-bar link type booster mechanism as its cutting mechanism, the boosting action of the booster mechanism does not lead to an increase in the size of the tool. , It is possible to significantly increase the power increase rate compared to the conventional pliers type, and it becomes possible to give a stronger cutting force to the blade part, and an optical fiber cable having a soft part around the core part with high hardness Even when the length of each lever member is set so that the hard core part can be cut without hindrance when cutting, it is possible to keep the required length as short as possible and keep the size of the tool compact. The deterioration of operability and workability can be minimized.

Further, in this case, the cutting speed is changed while keeping the stroke speed of the drive lever substantially constant.
It can be changed so that it is relatively large at the beginning of the cutting process and relatively small at the end of the cutting process. As a result, while keeping the stroke speed of the drive lever substantially constant, when cutting the surrounding soft part, it is cut quickly with a relatively low power increase factor, while when cutting the core part with high hardness, It is possible to set to cut slowly with a relatively high power factor corresponding to. That is, when cutting an optical fiber cable having a soft portion around the core portion having high hardness, it is possible to effectively cope with the change in hardness between the core portion and the surroundings, and to smoothly cut both these portions without any trouble. It becomes possible to effectively secure workability and cutting performance as an optical fiber cable cutter.

[0011]

By the way, in the case of a cutting tool which adopts the four-bar link type booster mechanism as its cutting mechanism as described above, the conventional pliers-like tool due to the boosting action of the booster mechanism. Although it is possible to significantly increase the power increase rate and to give a very strong cutting force to the blade portion, on the other hand, the tool itself, especially the blade portion, is subject to a heavy load. Therefore, in the case of such a cutting tool,
It is conceivable that the blade is inevitably severely worn and the tool life is shortened as it is repeatedly used for work requiring a large cutting force by taking advantage of its excellent characteristics.

The present invention has been made in view of the above problems, and in a cutting tool that employs a four-bar link type booster mechanism as its cutting mechanism, the tool life is extended with a relatively simple structure. The basic purpose is to provide a cutting tool capable of cutting.

[0013]

Accordingly, the present invention provides
A basic lever and a driven lever, each of which has a blade portion facing each other on one end side and is pivotally attached to each other at a first fulcrum portion, and a drive lever which is pivotally attached to an intermediate portion of the basic lever at one end side is a second fulcrum portion. And a link mechanism formed of a connecting lever, one end side of which is connected to the other end side of the driven lever and the other end side of which is connected to a middle portion of the drive lever,
The lever ratio is d / f where d: Distance from the second fulcrum of the drive lever to the connecting point with the connecting lever f: Distance between the connecting point between the driven lever and the connecting lever and the second supporting point And a lever mechanism having a variable lever ratio, and the other end portion of the basic lever and the other end portion of the drive lever serve as grip portions facing each other. The distance from the fulcrum to the connecting point with the connecting lever is set equal to the distance between both connecting points of the connecting lever, and the distance from the first supporting point of the driven lever to the connecting point with the connecting lever is set to the first. It is set longer than the distance between the first and second fulcrums by a slight eccentricity (e), and the drive lever is rotated to bring the distance (f) close to or equal to the minute eccentricity (e). The cutting lever with the maximum lever lever ratio. The basic lever and the driven lever each include a lever body and a blade portion plate having a blade portion at a part of its peripheral edge, and each blade portion plate is superposed on the inner side at one end side of each lever body. And is fixed to the lever body in a replaceable manner, and a step portion of a predetermined width is formed between the blade portion provided on each blade plate and the peripheral edge portion of the lever body corresponding to the blade portion. At least one of the fixing members for fixing the blade plate to the lever main body has its terminal side projecting inward through the blade plate, and the projecting portion, when the cutting tool is opened, It is characterized in that it is brought into contact with the lever main body corresponding to the other blade plate at a predetermined opening degree to restrict further opening movement of the lever main body.

[0014]

According to the present invention, the basic lever and the driven lever are each composed of the lever body and the blade plate, and each blade plate is replaceably fixed to the lever body. Therefore, when the blade is worn, the blade plate can be removed from the lever body and replaced with a new one. That is, it is possible to easily regain a sharpness similar to that of a new product simply by replacing the blade plate, and it is possible to extend the life of the tool. In addition, since a step portion having a predetermined width is formed between the blade portion provided on each blade plate and the peripheral edge portion of the lever body corresponding to the blade portion, both the lever bodies are closed to each other at the time of cutting. Even when combined, the cut portion of the work cut by the blade portion can escape by riding on the stepped portion, and the separation of the work at the time of cutting and the detachment from the blade portion can be smoothly performed. . In particular, when the blade is formed with an appropriate taper, the cutting portion of the work can ride on the stepped portion along this taper, so that the separation of the work and the separation from the blade can be performed more smoothly. Can be done. Further, at least one of the fixing members for fixing the blade plate to the lever body, the terminal side thereof penetrates the blade plate and projects inward, and the projecting portion is, when the cutting tool is opened, Since the lever body corresponding to the other blade plate is abutted at a predetermined opening and the further opening operation of the lever body is restricted, the protruding portion of the fixing member is the maximum in the opening operation of the cutting tool. It can be used as a stopper that determines the opening degree. Therefore, it is not necessary to separately provide such a stopper, and an increase in the number of parts can be suppressed.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Prior to explaining the specific configuration of the cutting tool according to the embodiment of the present invention and its operation,
First, the basic structure of the four-bar linkage type booster mechanism and its operating principle will be described. The principle description is basically the same as that of the four-bar linkage type booster disclosed in Japanese Patent No. 1791035.

FIGS. 15 and 16 show a fourth embodiment according to the present invention.
1 schematically shows a booster utilizing the basic principle of a node link mechanism. This booster includes a basic member 121.
And one end thereof was pivotally attached to the basic member 121 at the fulcrum A.
A drive lever 122 (rotatably supported), a connecting lever 123 having one end pivotally attached to the other end of the drive lever 122 at a connecting portion B (first connecting portion), and one end thereof at a fulcrum C. A driven lever 124 pivotally attached to the basic member 121 is provided, and the other ends of the connecting lever 123 and the driven lever 124 are rotatably connected by a follower F as a second connecting portion.

The drive lever 122 is reciprocally swung about the fulcrum A within a range of an angle α between a first position shown by a dotted line and a second position shown by a two-dot chain line. When the drive lever 122 is at the first position, the fulcrum C
The connection lever 123 and the driven lever 124 are provided at positions where the driven member F forms a downward opening obtuse angle around the driven element F. Also,
The length d of the drive lever 122 and the connecting lever 123 is set equal, and the length L of the driven lever 124 is set longer than the interval k between the fulcrums A and C by a minute length e (L = k + e, where e <k). As described above, the booster is constituted by using the four-bar linkage having the three levers 122, 123 and 124. This booster is basically based on a lever lever, and the lever ratio is given by d / FA. Where d
Is the length between the fulcrum A of the drive lever 122 and the connecting portion B, and FA is the length of the line connecting the fulcrum A and the follower F.

When the drive lever 122 is in the first position, the distance between the follower F and the fulcrum A has the largest value. From this state, if the drive lever 122 is swung in the clockwise direction around the fulcrum A, the coupling lever 123 is guided by the driven lever 124 and moves between the drive lever 122 and the coupling portion B as the center. While being rotated in the clockwise direction according to the drive lever 122 while reducing the angle θ formed by, the follower F causes the follower F to oscillate in the swinging direction of the drive lever 122 on the arc a of the radius L with the fulcrum C as the center of curvature. Is moved in the same direction as. When the drive lever 122 reaches the second position, the follower F approaches the fulcrum A with a slight eccentricity e. In this state, the distance between the follower F and the fulcrum A is minimized. That is, the lever lever ratio (magnification) is maximized. On the other hand, when the drive lever 122 swings in the counterclockwise direction, the connection lever 123 and the follower F are respectively moved in the opposite directions. That is, the drive lever 1
When 22 is reciprocally swung about the fulcrum A within the range of the angle α, the driven lever 124 is rotated by the angle β (β
The follower F is reciprocally rocked within the range of <α), and the follower F is reciprocally moved on the above-mentioned arc a.

The speed distribution curve of the follower F in the booster described above is as shown by V ₁ in FIG. 15 when the drive lever 122 is manually reciprocated at a substantially constant speed. In the vicinity of the fulcrum A, it moves extremely slowly. Further, when the drive lever 122 is driven by a motor (when the drive lever 122 reciprocates with a sinusoidal speed change), the speed distribution curve of the follower F is shown by V ₂ in FIG. And after all,
The speed of the follower F near the fulcrum A becomes extremely low. Therefore, if the present apparatus is applied to various types of pressurizing devices, the pressurizing device can be driven at an extremely low speed in the pressurizing step (stroke range in which the follower F exists near the fulcrum A).

In this device, the follower F has the connecting lever 12
The driven member F is guided by the driven lever 3 and the driven lever 124, and there is no sliding friction. Further, in this device, the smaller the minute eccentricity e, the smaller the speed at one end of the stroke of the follower F and the larger the pressing force. At that time, as shown in FIG. 16, the follower F and the fulcrum A are configured so as not to be in the same plane and do not contact with each other.
No matter how small, there is no problem structurally.
In the above-described booster, any tilt angle of the drive lever 122, in other words, any positions b ₀ , b ₁ ,.
The positions f ₀ , f ₁ , ... Of the follower F corresponding to (see FIG. 17) are determined as follows. That is, the point where the connecting portion B exists
Follower Ffi (i = 0,1 ,,) when existing in bi (i = 0,1, ...)
...) is a radius L '(L' is the length of the connecting lever 123) whose center of curvature is the aforesaid circular arc a representing the motion locus of the follower F.
It becomes the intersection with the circular arc ai (i = 0, 1, ...).

As described above, if the above-mentioned four-bar linkage type booster mechanism that operates based on such a basic principle is adopted, an extremely high magnification can be realized in the boosting action and movement of the output side. The speed can be made as slow as possible in the pressurizing step for the work, while it can be made relatively high in the non-pressurizing step.

Next, a cutting tool according to the present embodiment, which employs such a four-bar link type booster mechanism for the cutting mechanism, will be described. 1 and 2 are front explanatory views showing a state in which a blade portion of a cutting tool Tc according to the present embodiment is opened and a state in which the blade portions are closed to each other, respectively. 3 and 4 are a bottom view and a side view in which the blade portions of the cutting tool Tc are closed to each other. As shown in these drawings, the cutting tool Tc according to the present embodiment has a base lever 1 and a driven lever that have blade portions 4a and 34a facing each other at one end side and are pivotally attached to each other at a first fulcrum portion C. The lever 31, a drive lever 11 having one end side pivotally attached to the middle of the basic lever 1 at the second fulcrum portion A, one end side connected to the other end side of the driven lever 31, and the other end side of the drive lever 11. Connecting lever 21 connected to the middle part of 11
And these lever members 1, 11, 21, 31
Thus, a so-called 4-joint link mechanism (see the alternate long and short dash line in FIG. 1) is formed.

With this four-bar linkage, the lever lever ratio is d / f (where d is the second lever of the drive lever 11).
Distance from the fulcrum A to the connection B with the connection lever 21,
f: the connecting portion F between the driven lever 31 and the connecting lever 21 and the second
A lever mechanism having a variable lever lever ratio, which is the distance from the fulcrum portion A), is formed. Further, the other end of the basic lever 1 and the other end of the drive lever 11 constitute grip parts 3 and 13 which face each other. It should be noted that one end side of the basic lever 1 and one end side of the driven lever 31 are supported by a bolt-shaped first pivot shaft 41, and a middle portion of the basic lever 1 and one end side of the drive lever 11 are supported by a second pivot support. By the shaft 42, the other end side of the driven lever 31 and one end side of the connecting lever 21 are connected by the first connecting shaft 43, and further, the other end side of the connecting lever 21 and the intermediate part of the drive lever 11 are set by the second connecting shaft 43. The connecting shafts 44 are rotatably connected to each other. That is, the first and second pivot shafts 41 and 42 and the first and second pivot shafts
The axes of the connecting shafts 43 and 44 are respectively the first and the second.
It corresponds to the fulcrums C and A and the connecting portions F and B.

In this embodiment, the second lever of the drive lever 11 is used.
Distance from fulcrum A to connection B with connection lever 21
(d) and the distance between the connecting portions B and F of the connecting lever 21 are set equal, and the distance from the first fulcrum portion C of the driven lever 31 to the connecting portion F of the connecting lever 21 is Smaller eccentricity than the distance between the first and second fulcrums C and A
(e) is set to be long, and the drive lever 11 is rotated to bring the distance (f) closer to or equal to the minute eccentricity amount (e), and based on the basic principle described above, The maximum lever lever ratio can be obtained.
At this time (that is, when the connecting portion F approaches the second fulcrum portion A due to the closing operation of the drive lever 11 and the lever lever ratio reaches the maximum), the connecting portion F (follower) is connected to the fulcrum A. In the vicinity, it moves at an extremely low speed, so that the moving speed of the blade portion of the driven lever 31 also becomes small and the cutting speed becomes extremely slow.

As described above, according to the cutting tool Tc,
By combining the levers 1, 11, 21, and 31 as described above to form a four-bar link type booster mechanism, it is possible to perform an extremely high power boosting action, which leads to an increase in the size of the tool. Instead, it is possible to significantly increase the power increasing rate as compared with the conventional pliers-like one, and to give a stronger cutting force to the blade portions 4a and 34a.

Therefore, when the above cutting tool Tc is used as an optical fiber cable cutter for cutting an optical fiber cable having a soft portion around a core material portion having high hardness, for example, a hard core material portion can be cut without trouble. Even if the length of each lever member is set as described above, the required length can be suppressed as short as possible to keep the size of the tool compact, and the deterioration of operability and workability can be minimized. Can be turned on. Moreover, in this case, for example, in FIG.
As shown in, while the stroke speed of the drive lever 11 is kept substantially constant, the cutting speed can be changed so as to be relatively high at the beginning of the cutting process and relatively low at the end of the cutting process. Of. As a result, while the stroke speed of the drive lever 11 is kept substantially constant, when cutting the surrounding soft portion, the cutting speed is relatively high at a relatively low power increase rate, while when cutting the core material portion having high hardness, It becomes possible to set to cut slowly with a relatively high power increase rate commensurate with this. In other words, when cutting an optical fiber cable that has a soft part around the core part with high hardness, it is possible to effectively respond to changes in hardness between the core part and the surroundings and to smoothly cut both parts. Therefore, the workability and cuttability as an optical fiber cable cutter can be effectively ensured.

By the way, in the present embodiment, as a result of the cutting tool Tc being repeatedly used for work requiring a large cutting force,
If the blades 4a, 34a wear out beyond a certain limit, it is relatively easy to replace the blades 4a, 34a with a new one.
The tool life can be extended. That is, in the present embodiment, the basic lever 1 and the driven lever 31 are respectively composed of the lever bodies 2 and 32 and the blade portion plates 4 and 34 provided with the blade portions 4a and 34a on a part of their peripheral edges. The blade plates 4 and 34 are the lever bodies 2 and
The lever 32 is superposed on the inner side at one end side thereof and is fixed to the lever bodies 2 and 32 in a replaceable manner.

Hereinafter, each part of the cutting tool Tc will be described with reference to FIGS. 8 to 14. As shown in FIG. 8, the lever body 2 of the basic lever 1 is formed in a substantially flat plate shape as a whole, and the tip side from the middle part in the longitudinal direction is lowered by a predetermined amount, as can be seen from FIG. Has been done. Then, through holes 2a and 2b through which the first pivot shaft 41 and the second pivot shaft 42 are inserted, respectively, are formed substantially in the middle of the stepped-down portion. Also,
The tip end side of the stepped-down portion has a bent shape in a plan view, and a through-hole 2c into which a fixing bolt 48 as a fixing member for fixing the blade plate 4 to the lever body 2 is inserted into this portion. Is provided. Further, on the other end side of the lever main body 2 of the basic lever 1, for example, a pair of holes 2d for fixing the grip part 3 made of resin is provided.

The lever body 12 of the drive lever 11 is shown in FIG.
As shown in FIG. 2, the plate is formed in a straight plate shape as a whole and extends straightly. One end side thereof has a through hole 12a through which the second pivot shaft 42 is inserted, and the other end side thereof has a second connecting shaft 44. A through hole 12b to be inserted is formed. A pair of holes 12c for fixing the grip portion 13 made of resin, for example, is provided further on the terminal side than the through hole 12b. Further, as shown in FIG. 10, the connecting lever 21 is formed in a straight plate shape extending straightly, and has a through hole 21a through which the first connecting shaft 43 is inserted at one end side thereof and a first through hole 21a at the other end side thereof. A through hole 21b for inserting the two connecting shafts 44 is formed.

Further, the lever body 32 of the driven lever 31
As shown in FIG. 11, is formed in a flat plate shape as a whole, and its tip end side has a bent shape in a plan view.
Then, in this portion, a through hole 32c for inserting a fixing bolt 49 as a fixing member for fixing the blade plate 34 to the lever body 32 is provided. Further, a through hole 32b through which the first connecting shaft 43 is inserted is formed on the other end side of the lever main body 32, and a screw portion of the first pivot shaft 41 and a screw portion are provided between the through holes 32b and 32c. Female thread 32a
Is provided.

On the other hand, the blade plate 4 of the basic lever 1 and the blade plate 34 of the driven lever 31 are both flat and have the same planar shape. For example, the driven lever 31 side is taken as an example. More specifically, as shown in FIG. 12, one side has a bent shape in plan view corresponding to the shape of the tip side of the lever body 32 of the driven lever 31. Then, fix the fixing bolt 49 (basic lever 1
On the other side, a female screw portion 34d (4d) for screwing the fixing bolt 48) is provided, and a through hole 34e (4e) for inserting the first pivot shaft 41 is formed on the other end side. There is. Further, a blade portion 34a (4a) is formed on the peripheral edge on one side of the bent portion of the blade portion plate 34, and the blade portion 34a (4a)
As shown in FIG. 13, a) has a taper portion 34b (4b) having a predetermined inclination angle on one side.

When constructing the cutting tool Tc by assembling the above respective parts, first, the blade plates 4 and 34 are superposed on the inner sides of the corresponding one ends of the lever bodies 2 and 32, respectively. Then, the centers of the female screw portions 4d and 34d of the blade plates 4 and 34 and the through holes 2 of the lever main bodies 2 and 32, respectively.
The centers of c and 32c are aligned with each other, and the fixing bolts 48 and 49 are used to fasten and fix the lever bodies 2 and 32. That is, the blade plates 4 and 34 are replaceably fixed to the lever bodies 2 and 32. The blade plate 4
The through hole 4e and the through hole 2a of the basic lever 1, and the through hole 34e of the blade plate 34 and the female screw portion 32a of the lever body 32 of the driven lever 31 are also overlapped so that their centers coincide with each other. At this time, as shown in FIG. 14, the blade portions 4a, 4a provided on the blade plate 4, 34,
Stepped portions 5 and 35 having a predetermined width are formed between 34a and the peripheral portions of the lever bodies 2 and 32 corresponding to the blade portions 4a and 34a, respectively.

By providing the step portions 5 and 35, even when the both lever main bodies 2 and 32 are closed with each other at the time of cutting, the cut portion of the work W cut by the blade portions 4a and 34a has the above step difference. The work W can be escaped by riding on the parts 5 and 35, and the work W can be smoothly separated during cutting and separated from the blade parts 4a and 34a. Particularly, since the blade portions 4a, 34a are formed with the tapered portions 4b, 34b, the cut portion of the work W is cut along the taper portions 4b, 34b.
5, the work W can be separated and separated from the blades 4a and 34a more smoothly.

Next, the through hole 12a of the lever body 12 of the drive lever 11 and the through hole 2 of the lever body 2 of the basic lever 1
b, the through hole 12b of the lever body 12 of the drive lever 11, the through hole 21b of the connecting lever 21, and the connecting lever 21.
The through hole 21a of the driven lever 31 and the through hole 32b of the lever body 32 of the driven lever 31 are overlapped so that their centers coincide with each other, and then the second pivot shaft 42, the second connecting shaft 44, and the first connecting shaft 44, respectively. 43, and these shaft members 42, 4
The second fulcrum A and the connecting portions B and F are rotatably supported by 4, 43.

After that, the driven lever 31 is superposed on the basic lever 1. That is, the through hole 2a of the basic lever 1, the through hole 4e of the blade plate 4, and the blade plate 3
Through hole 34e of 4 and lever body 3 of driven lever 31
The two female screw portions 32a are overlapped so that their centers coincide with each other. As a result, as can be seen from FIGS. 4, 5 and 6, the basic lever 1
The lever body 2, the blade plate 4, the blade plate 34, and the lever body 32 of the driven lever 31 are superposed. Then, the bolt-shaped first pivot shaft 41 is passed from the basic lever 1 side, and the washer member 52 is passed from the driven lever 31 side.
Then, the split nut 51 is screwed onto the first pivot shaft 41 and tightened.

On the tip side of the first pivot 41, for example, 6
Pin holes are bored at 0 degree intervals. The pin holes are aligned with one of the split grooves 51a of the split nut 51, and the split pin 53 is inserted therethrough, so that the first pivot shaft 41 and the split nut 51 are inserted. Stop the rotation of. As described above, the split nut 5
Instead of using 1 and split pin 53 to prevent rotation,
It is also possible to make a non-rotating cap nut by screwing it into the threaded portion of the first pivot shaft 41 and tightening it so as to adjust steplessly.

At least one of the fixing bolts 48 and 49 (both in this embodiment) for fixing the blade plates 4 and 34 to the lever main bodies 2 and 32 has the blade plate 4, 4 on the end side. It penetrates through 34 and protrudes inward. In the present embodiment, the protrusion 48a of the fixing bolt 48 on the basic lever 1 side abuts the lever body 32 of the driven lever 31 at a predetermined opening when the cutting tool Tc is opened, and the lever body 32 is opened. The position of the fixing bolt 48 is set so as to restrict the further opening movement of the fixing bolt 48.

That is, the protruding portion 48a of the fixing bolt 48 serves as a stopper that determines the maximum opening degree in the opening operation of the cutting tool Tc. Therefore, it is not necessary to separately provide such a stopper, and an increase in the number of parts can be suppressed.

In the cutting tool Tc assembled as described above, when the blade portions 4a, 34a of the cutting tool Tc are worn and hinder the use thereof, first, the cotter pin 53 is reversed, contrary to the above-mentioned assembly. Is disengaged, the split nut 51 is loosened and extracted from the first pivot shaft 41, and then the first pivot shaft 41 is disengaged to release the connection between the basic lever 1 and the driven lever 31. Then, the fixing bolt 48 or 49 is loosened and pulled out, and the blade portion plate 4 provided with the worn blade portion 4a or 34a.
Alternatively, the 34 may be replaced with a new one and then reassembled.

As described above, according to the present embodiment, the basic lever 1 and the driven lever 31 are composed of the lever bodies 2 and 32 and the blade plates 4 and 34, respectively. Is fixed to each of the lever main bodies 2 and 32 in a replaceable manner. Therefore, when the blade portions 4a and 34a are worn, the blade portion plates 4 and 34 are attached to the lever main bodies 2 and 3.
It can be removed from 2 and replaced with a new one. That is, just by replacing the blade plates 4 and 34, the sharpness similar to that of a new product can be easily restored, and the life of the tool can be extended.

The present invention is not limited to the above-mentioned embodiments, and within the scope of the invention,
It goes without saying that various improvements or design changes are possible.

[Brief description of the drawings]

FIG. 1 is a front view showing a state in which a blade portion of a cutting tool according to an embodiment of the present invention is opened.

FIG. 2 is a front view showing a state in which the blade parts of the cutting tool are closed to each other.

FIG. 3 is a bottom view of the cutting tool in which the blade portions are closed to each other.

FIG. 4 is a side view of the cutting tool in which the blade portions are closed to each other.

5 is a view from the direction of XX in FIG.

6 is a cross-sectional explanatory view taken along the line YY of FIG.

FIG. 7 is an explanatory diagram showing a relationship between an opening / closing speed of a drive lever of the cutting tool and a cutting speed.

FIG. 8 is a front explanatory view of a lever body of a basic lever of the cutting tool.

FIG. 9 is a front explanatory view of a lever body of a drive lever of the cutting tool.

FIG. 10 is a front explanatory view of a connecting lever of the cutting tool.

FIG. 11 is a front explanatory view of a lever body of a driven lever of the cutting tool.

FIG. 12 is a front explanatory view of a blade plate of the cutting tool.

13 is an explanatory cross-sectional view taken along the line ZZ of FIG.

FIG. 14 is an explanatory sectional view showing an assembled state of the lever body and the blade plate.

FIG. 15 is an explanatory view schematically showing a four-bar link type booster for explaining the operating principle of the cutting tool.

FIG. 16 is a schematic explanatory view showing a planar shape of the booster.

FIG. 17 is an explanatory diagram showing how to determine the position of the follower in the booster.

[Explanation of symbols]

 1 ... Basic lever 2, 32 ... Lever body 3, 13 ... Grip portion 4, 34 ... Blade portion plate 4a. 34a ... Blade 5, 35 ... Step 11 ... Drive lever 21 ... Connection lever 31 ... Follower lever 48 ... Fixing bolt A ... Second fulcrum C ... First fulcrum Tc ... Cutting tool W ... Workpiece

Claims (1)

[Claims] 1. A basic lever and a driven lever pivotally attached to each other at a first fulcrum portion, each having a blade portion facing each other on one end side, and one end side having a second fulcrum portion pivotally connected to an intermediate portion of the basic lever. A lever mechanism that uses a link mechanism formed of a drive lever attached to the driven lever and a connecting lever whose one end side is connected to the other end side of the driven lever and the other end side is connected to an intermediate part of the drive lever. Is d / f where d is the distance from the second fulcrum part of the drive lever to the connection point with the connecting lever f: The lever is the distance between the connection point between the driven lever and the connecting lever and the second fulcrum part A booster mechanism with a variable lever ratio is formed, and the other end portion of the basic lever and the other end portion of the drive lever are configured as a grip portion facing each other, and a second fulcrum portion of the drive lever is provided. The distance to the connection point with the connection lever and the above The distance between both connecting points of the lever is set equal, and the distance from the first supporting point of the driven lever to the connecting point with the connecting lever is smaller than the distance between the first and second supporting points. (e) Longer setting, and by rotating the drive lever to make the distance (f) closer to or equal to the minute eccentricity amount (e), the maximum lever lever ratio is obtained. In the tool, the basic lever and the driven lever each include a lever body and a blade plate provided with a blade at a part of a peripheral edge thereof, and each blade plate is superposed on the inner side at one end side of each lever body. After being combined, they are fixed to the lever body in a replaceable manner, and a step portion having a predetermined width is formed between the blade portion provided on each blade plate and the peripheral edge portion of the lever body corresponding to the blade portion. The blade plate At least one of the fixing members to be fixed to the main body has its terminal side penetrating the blade plate and projecting inward, and the projecting part is the other at a predetermined opening when the cutting tool is opened. A cutting tool which abuts against a lever body corresponding to a blade plate and restricts further opening movement of the lever body.