JP3066414B2 - Manual cutting tool - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manual cutting tool, particularly to a manual cutting tool capable of cutting large-diameter cables and wires.

2. Description of the Related Art Conventionally, a manual cutting tool capable of cutting a large-diameter cable or wire has been proposed in Japanese Patent Publication No. 58-28049.

As shown in FIGS. 4 and 5, the hand-operated cutting tool has a first grip 2 and a second grip 3 provided with a fixed blade 1 having a curved front end, and a leg 4 is opened by a shaft 4. A sickle-shaped rotary blade 6, which is pivotally supported and has fine ratchet teeth 5 formed on the outer surface at the tip of the fixed blade 1, is axially attached by a shaft 8 so as to surround an object 7 such as a cable. And a ratchet claw 9 meshing with the ratchet teeth 5 is attached to the second grip 3 by a shaft 10 near the shaft 4, and the first and second grips 2, 3 are repeatedly opened and closed. By doing so, the ratchet pawl 9 is reciprocated along the outer surface of the rotary blade 6, and the rotary blade 6 is rotated stepwise in a direction in which the width of the fixed blade 1 decreases, and finally the width is reduced to zero. To cut the object 7 positioned between them.

[Problems to be Solved by the Invention] However, the ratchet pawl 9 in the conventional manual cutting tool is provided with the first grip 2 provided on the second grip 3.
While the first and second grips 2 and 3 are opened and closed, while expanding the angle θ formed with the second grip 3 when the first and second grips 2 and 3 are opened and closed. That is, the ratchet pawl 9 itself moves in the feed direction along the outer surface 6a of the rotary blade 6 while falling down. On the other hand, the ratchet pawl 9 has a configuration in which a pair of engaging claws 11a and 11b are provided at the tip, and the outer surface 6e of the rotary blade 6 on which the ratchet teeth 5 are formed has an arcuate shape at the first meshing position. Are gradually moved away, the pawls 11a and 11b have a large contact area with the ratchet teeth 5 when the ratchet pawl 9 reciprocates with the opening and closing operations of the first and second grips 2 and 3. Is extremely short, and the contact area is small in most of the sections during the stroke, so that a large cutting load is applied to the small engaging portion, and the ratchet claw 9 and the ratchet teeth 5 are easily damaged. Further, it is difficult to increase the feed distance of the ratchet in one opening / closing operation of the grip portions 2 and 3, and the cutting operation is not easy because the opening and closing must be repeated many times. Further, the conventional ratchet pawl has an outer surface having substantially the same radius of curvature as the rotary blade, and has an advantage that the ratchet pawl and the ratchet teeth mesh in a stable state, but on the other hand, they engage with the ratchet teeth. Since the number of ratchet pawls is limited, there is also a drawback that the amount of feed of the ratchet with respect to the rotation of the drive handle is small and the cutting efficiency is not good.

In addition, the present applicant has disclosed that the ratchet pawl is always in a stable state irrespective of the opening and closing of the drive handle, and that the ratchet teeth are engaged with two or more pawls so that the manual operation with excellent functionality and durability is achieved. A cutting tool was filed earlier (Japanese Patent Laid-Open No. 62-94214).

However, in the manual cutting tool presented in the above publication, the first arm connected to the drive handle and the second arm connected to the fixed handle are connected to both ends of the ratchet pawl to form a link mechanism, and The outer surface of the ratchet pawl has substantially the same radius of curvature as the rotary blade, and two or more pawls meshing with the ratchet teeth of the rotary blade are formed.

However, the manual cutting tool having the conventional link mechanism has a complicated structure and a high manufacturing cost because of having the link mechanism having the first arm and the second arm, and also has a ratchet via the link mechanism. The operating feeling of the handle is not good for operating the pawl, and the driving force is reduced due to the dispersal of the pressing force. In addition, there is a problem that the margin of feeding of the ratchet pawl for opening and closing operation of the handle is small and the operation efficiency is not good. In the embodiment, the number of pawls is limited to three and the ratchet feeding efficiency is not sufficient.

The present invention has been made to improve this point,
An object of the present invention is to provide a manual cutting tool having excellent operation efficiency, having a large cutting force, and also having excellent durability.

Means for Solving the Problems According to the present invention, a first grip portion and a second grip portion having a curved fixed blade at a tip portion are pivotally supported so that a leg can be opened and the fixed blade is provided. In a manual cutting tool having a ratchet tooth on the outer surface at the tip of a sickle, a preformed sickle-shaped rotary blade is axially attached so as to surround the object to be cut, and the second grip portion is engaged with the ratchet tooth. A mating ratchet pawl was pivoted forward on a manual cutting tool directly pivoted to the second grip (3) at an inwardly lower portion of the shaft (4) pivotally supporting the second grip (3). In a manual cutting tool, at least three or more ratchet claws are formed without a gap between a tip and a mounting shaft of a base on a side surface having a radius of curvature substantially equal to or greater than a radius of curvature of an outer surface of the rotary blade. The above-described section having a configuration having an engagement claw To solve the problem.

[Operation] When the grip portion is opened and closed, at least one of the engaging claws of the ratchet pawl meshes with the ratchet teeth with a large contact area over substantially the entire stroke of one opening / closing operation, thereby eliminating an uncertain meshing state. In addition, when the ratchet feed is performed at the distal end and the base end side of the ratchet pawl in which the engaging pawl is disposed along a radius of curvature substantially equal to or more than that of the outer surface of the rotary blade, a circle centered on its mounting axis. It moves on the circumferential locus and moves away from the ratchet teeth to prevent the two from meshing tightly and becoming tight. Further, by setting the ratchet pawl to be substantially equal to or larger than the radius of curvature of the outer surface of the rotary blade, the engagement of the ratchet pawl with the ratchet teeth during one drive handle operation is increased, thereby improving the cutting efficiency.

Example Next, an example of the present invention will be described with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention. The whole structure is almost the same as that of the above-mentioned conventional example, and a first grip portion provided with a curved fixed blade 1 at a front end portion is shown. The second grip portion 2 and the second grip portion 3 are pivotally supported by a shaft 4 so that they can be opened apart from each other, and a sickle-shaped rotary blade 6 having fine ratchet teeth 5 formed on an outer surface thereof is used to cut an object 7 such as a cable. A ratchet claw 9 which is axially attached to the tip of the fixed blade 1 so as to surround the fixed blade 1 and which engages with the ratchet teeth 5 at the second grip portion 3 is attached to the shaft 10 by a shaft 10 at a lower part in the inward direction of the shaft 4. Have been. The ratchet pawl 9 is located on the outer surface of the rotary blade 6.
For example, six engaging claws 11a, 11ba, 11 are provided between the tip of the outer surface 9a having the same radius of curvature as that of 6a and the shaft attachment portion of the base.
c, 11d, 11e, and 11f are formed.

In the drawings, reference numeral 12 denotes a reverse rotation preventing claw of the rotary blade 6 that engages with the ratchet teeth 5, reference numerals 13 and 14 denote springs for urging the ratchet claw 9 and the reverse rotation preventing claw 12 toward the ratchet teeth 5, and 15 denotes a spring. This is a helical spring that always presses the first and second grips 2, 3 to the open position.

In the embodiment having such a configuration, the rotary blade 6 is turned to the position shown by a two-dot chain line in FIG. It is turned and sandwiched between the fixed blade 1 and the rotary blade 6 as shown by the solid line in FIG. At this time, the ratchet pawl 9 has the frontmost engaging pawl 11a engaged with the ratchet teeth 5.

Next, when the grip portions 2 and 3 are closed, the ratchet pawl 9 moves along the outer side surface 6a of the rotary blade 6, and the rotary blade 6 rotates about the shaft 8 by the amount of the ratchet feed, and the rotary blade 6 and the fixed blade 1 Mouth width decreases. Therefore, the fixed blade 1 and the fixed blade 6 cut into the workpiece 7 inserted between them by an amount corresponding to a decrease in the mouth width.

When the grips 2 and 3 are opened, the legs are released by the urging force of the spring 15, and the grips 2 and 3 are opened. At this time, the rotary blade 6 is still fixed at the original position by the reverse rotation preventing claw 12, and prepares for the next ratchet feed.

By repeating these opening and closing operations, finally, the width of the fixed blade 1 and the rotary blade 6 is reduced to zero, and the object 7 is completely cut.

In this embodiment, the ratchet pawl 9 has six engaging pawls 11.
.. 11f are formed, unlike the conventional case having two engaging claws, during the cutting operation.
... At least one of 11f is securely engaged with ratchet teeth 5 with a large contact area in order from the tip, so that ratchet feed is reliable, a large cutting force can be exerted, and a hard cut object is provided. 7 can be cut, the width of a single ratchet feed can be increased, and quick cutting can be performed. In addition, the ratchet teeth 5 and the engaging claws 11a,.・
・ Excellent durability without worrying about 11f being damaged. Also, since the engaging claws 11a,..., 11f of the ratchet pawl 9 are provided along substantially the same radius of curvature as the outer side surface 6a of the rotary blade 6, the front and rear ends thereof are attached during ratchet feeding. It moves on a circumferential trajectory about the shaft 10 and moves away from the ratchet teeth 5 to prevent the two from meshing tightly and becoming tight.

In particular, in this embodiment, the engagement claws 11a of the ratchet claw 9 are provided.
... 11f is formed without a gap up to its mounting shaft 10, exerts a greater leverage action than the conventional one in which an engagement claw is formed at the tip of the ratchet claw, and has a large cutting force. To provide an easy-to-use cutting tool that is excellent in cutting efficiency because it can be cut more greatly by operating the handle of the handle, and particularly easy to cut near the closed leg position of the gripping parts 2, 3 that are hard to apply force. Can be.

In this embodiment, the ratchet pawl 9 has six engaging pawls 11a, 11b, 11c, 11d, 11e and 11f formed on an outer surface 9a having substantially the same radius of curvature as the outer surface 6a of the rotary blade 6. The engagement claws 11a, 11b, 11c, 11d, 11e and 11f can be sequentially engaged with the ratchet teeth 5 in a stable state and a larger cutting can be performed by one handle operation in a stable state. However, by making the ratchet pawl 9 larger than the radius of curvature of the outer surface 6a of the rotary blade 6, that is, closer to a straight line, more engaging claws can be formed, so that the cutting efficiency can be further improved.

[Effects of the Invention] According to the present invention, since the ratchet pawl has a radius of curvature substantially equal to or greater than that of the rotary blade, it is possible to always engage at least one engaging pawl with the ratchet tooth with a large contact area. It is possible to obtain a large cutting force, and it is excellent in durability without inconvenience such as breakage of ratchet teeth, and at least three or more engaging claws are provided between the tip on the side surface of the ratchet pawl and the mounting shaft. Are formed without any gaps, so that it is possible to increase the feed width of the ratchet.

Furthermore, by setting the ratchet pawl to be substantially equal to or greater than the radius of curvature of the outer surface of the rotary blade, the number of ratchet pawls meshing with the ratchet teeth can be increased by one operation of the driving handle, thereby further improving the cutting efficiency. It is possible to do.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a front view, FIG. 2 and FIG. 3 are explanatory views showing a use state, and FIG. 4 and FIG. FIG. 4 is a front view showing a conventional example, and FIG. 5 is an explanatory view showing a use state. 1 ... fixed blade, 2, 3 ... grip part, 4 ... axis, 5 ... ratchet teeth, 6 ... rotary blade, 7 ... object to be cut, 8 ... axis,
9 ... ratchet pawls, 11a, 11b, 11d, 11e, 11f ... engaging pawls.

Claims (1)

(57) [Claims] A first grip (2) having a curved fixed blade (1) at its tip and a second grip (3) are pivotally supported so that the legs can be opened and fixed. Blade (1) Sickle-shaped rotary blade (6) with ratchet teeth (5) formed on the outer surface at the tip
Is pivotally mounted so as to surround the object to be cut, and a ratchet pawl (9) meshing with the ratchet teeth (5) is pivoted on the second grip (3), and the second grip (3) is pivoted on the second grip (3). The second grip portion (3) at an inwardly lower portion of the supporting shaft (4).
In the manual cutting tool directly mounted on the rotary blade, the ratchet pawl (9) has a radius of curvature substantially equal to or greater than the radius of curvature of the outer surface of the rotary blade (6). A manual cutting tool having at least three or more engaging claws (11a, 11b, 11c, 11d, 11e, 11f) formed with no gap between them.