Cutting tool

Abstract

To provide a tool for firmly holding an object to be cut such as a resin pipe, and can satisfactorily cut the object to be cut.SOLUTION: A cutting tool includes first and second levers 10 and 20 which are rotatably connected to each other by a rotation shaft 1, and whose rear parts are provided as operation parts 12 and 22, and a cutting blade 30 provided on the first lever 10. The second lever 20 is provided with a receiving part 24, and a regulation part 26 facing the receiving part 24 along a moving track of the cutting blade 30. A holding space 28 is formed between a receiving surface 24a of the receiving part 24 and a regulation surface 26a of the regulation part 26. The holding space 28 has an opened front side, and becomes gradually narrow toward the inside. A resin pipe 100 is held between the receiving surface 24a and the regulation surface 26a by pushing the resin pipe 100 toward the inside the holding space 28 from front. The second lever 20 is provided with a moving member 40 movable in a longitudinal direction, and the moving member 40 presses the resin pipe 100 held by the holding space 28 from the front.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a cutting tool for cutting a resin pipe or the like. [Background technology]

[0002] The cutting tool for a plastic pipe (object to be cut) disclosed in Patent Document 1 includes first and second levers rotatably connected by a rotating shaft, and a cutting blade provided on the first lever. The second lever is provided with a receiving part, and this receiving part is formed with a recess that is open upward. With the plastic pipe set in this recess, the rear parts (operating parts) of the first and second levers are closed so as to move closer to each other, whereby the cutting blade passes through the recess from above and cuts the plastic pipe.

[0003] The cutting tool disclosed in Patent Document 2 has a movable member at the tip of the second lever that is rotatable or linearly movable, and this movable member is moved toward a plastic pipe set in the receiving part of the second lever to hold the plastic pipe. As a result, the receiving part and the movable member open the upper part and form a recess. The size of this recess corresponds to the diameter of the plastic pipe. In this state, by closing the first and second levers, the cutting blade passes through the recess from above and cuts the plastic pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4790942 [Patent Document 2] JP 2007-54391 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the cutting tools of Patent Documents 1 and 2, the recess in which the plastic pipe is set is open upward, and the cutting blade reaches the plastic pipe from the opening of this recess. Therefore, the plastic pipe is unstable when held before and immediately after cutting begins, and the plastic pipe may be cut at an angle to the pipe axis. In particular, when the object to be cut is composed of an inner pipe and a covering pipe covering its outer periphery, such as a composite pipe used for cold and hot water supply, the inner pipe may shift from the set position when force is applied to the covering pipe by the cutting blade, and the inner pipe tends to be cut at an angle. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a cutting tool comprising first and second levers rotatably connected to each other by a rotating shaft, the rear of which serves as an operating part, and a cutting blade provided on the first lever, in which the operating parts of the first and second levers are brought closer to each other so that an object to be cut is received by a receiving part provided on the second lever and cut by the cutting blade, wherein the second lever is provided with a regulating part facing the receiving part along a movement trajectory of the cutting blade, the receiving part and the regulating part respectively have receiving surfaces and regulating surfaces facing each other, a clamping space for clamping the object to be cut is formed between the receiving surface and the regulating surface, and the clamping space is open at the front and gradually narrows towards the back. According to this configuration, the object to be cut is pushed into the clamping space of the second lever and clamped by the receiving surface and the restricting surface, so that the object to be cut can be held firmly, and the object to be cut can be prevented from shifting during cutting, and can be cut well. When the object to be cut is a resin pipe, a cut surface perpendicular to the pipe axis can be obtained. In particular, when the resin pipe is a compound pipe having an inner pipe and a soft covering pipe covering the outer periphery of the inner pipe, the compound pipe is pushed into the clamping space, the covering pipe is crushed by the receiving surface and the restricting surface, and the inner pipe can be firmly held, so that the inner pipe can be cut with a cut surface perpendicular to the pipe axis.

[0007] Preferably, the second lever is further provided with a movable member that is movable in the front-rear direction and presses from the front the object to be cut that is held in the holding space. According to this configuration, the movable member presses the object set in the clamping space from the front, so that the object is held even more firmly and better cutting can be performed.

[0008] Preferably, a receiving groove is formed in the receiving surface to receive the cutting edge of the cutting blade, the receiving surface having a pair of surface areas on both sides of the receiving groove in the rotational axis direction, a slit is formed in the regulating portion through which the cutting blade passes, the regulating surface having a pair of surface areas on both sides of the slit in the rotational axis direction, and the movable member has a pair of holding portions located on both sides of the receiving portion and the regulating portion in the rotational axis direction. According to this configuration, the object to be cut is held on both sides of the cutting blade, so that the object can be held more stably.

[0009] Preferably, the second lever is provided with a maintaining means for maintaining a state in which the movable member presses against the object to be cut. According to this configuration, the cutting operation can be performed with the hands removed from the movable member, thereby improving workability.

[0010] More preferably, the retaining means includes a spring which biases the movable member rearwardly.

[0011] When the object to be cut is an inner tube and a covering tube covering the outer periphery of the inner tube, the length of the cutting blade is preferably set to πD / 2 or more (where D is the outer diameter of the covering tube). According to this configuration, even if the cladding tube is crushed flat during cutting, it is possible to cut the cladding tube without leaving any part uncut. Effect of the Invention

[0012] According to the present invention, the object to be cut can be held securely, and therefore the object can be cut satisfactorily. [Brief description of the drawings]

[0013] [Figure 1] 1 is a side view of a cutting tool according to a first embodiment of the present invention; [Diagram 2] FIG. [Diagram 3] 10 is a side view of a main portion showing a process of setting a plastic pipe to be cut on the cutting tool. FIG. [Figure 4] 13 is a side view of a main part showing a process of pressing the set resin pipe with a movable member. FIG. [Diagram 5] 4 is an enlarged cross-sectional view of a main portion illustrating the action of a cutting tool when cutting a composite pipe consisting of an inner pipe and a covering pipe. FIG. [Figure 6] FIG. 5 is a view equivalent to FIG. 4 showing the case where a small-diameter plastic pipe is cut. [Figure 7] FIG. 6 is a side view of a main portion of a cutting tool according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] A cutting tool according to a first embodiment of the present invention will be described below with reference to Figs. 1 to 6. As shown in Figs. 1 and 2, the cutting tool mainly comprises a first lever 10, a second lever 20, and a cutting blade 30. A front end of the first lever 10 and an intermediate portion of the second lever 20 serve as connecting portions 11 and 21, respectively. A receiving hole 21a is formed in the connecting portion 21 of the second lever 20, and the connecting portion 11 of the first lever 10 is received in this receiving hole 21a. The first lever 10 and the second lever 20 are rotatably connected by a rotating shaft 1 that passes through the connecting portions 11 and 21. The rear portions of the first lever 10 and the second lever 20 are provided as operating parts 12, 22 to be grasped by hand to open and close the lever. Although not shown, the operating parts 12, 22 are biased in the opening direction by a spring, and are prevented from opening beyond a predetermined opening angle by a restricting means.

[0015] An attachment slit 11a is formed in the center of the thickness direction (direction of the rotation axis 1) of the connecting part 11 of the first lever 10, and an end of the cutting blade 30 is inserted and fixed into this attachment slit 11a. For example, the cutting blade 30 is fixed to the connecting part 11 of the first lever 10 at two points by fixing pins or fixing screws (not shown). The cutting blade 30 extends forward along the longitudinal direction of the operating part 12 of the first lever 10.

[0016] A receiving portion 24 is formed at the bottom of the front wall 21b of the connecting portion 21 of the second lever 20, and a restricting portion 26 is formed at the top. The receiving portion 24 extends linearly forward along the longitudinal direction of the operating portion 22, and has a rectangular cross section. The upper surface of the receiving portion 24 is provided as a flat receiving surface 24a that receives the object to be cut. A receiving groove 25 is formed in the center of the receiving surface 24a in the width direction (direction of the rotation axis 1), extending longitudinally over the entire length of the receiving surface 24a. The receiving surface 24a has a pair of surface areas 24x on both sides of the receiving groove 25 in the width direction.

[0017] The restricting portion 26 has a triangular shape when viewed from the direction of the rotation axis 1, and its width is the same as or slightly smaller than that of the receiving portion 24. The upper surface of the restricting portion 26 is substantially flush with the upper surface of the connecting portion 21, and its lower surface is provided as a flat restricting surface 26a that restricts the cutting target. The restricting surface 26a extends linearly and faces the receiving surface 24a at an inclination that forms an acute angle. A clamping space 28 that is open to the front is formed between the receiving surface 24a and the restricting surface 26a. The interval between the receiving surface 24a and the restricting surface 26a gradually widens toward the front. In other words, the interval gradually narrows toward the rear (the back of the clamping space 28).

[0018] A slit 27 is formed in the center of the restricting portion 26 in the width direction, dividing the restricting portion 26 in half over the entire area. The slit 27 extends rearward and penetrates the front wall 21b of the connecting portion 21, and is connected to the receiving hole 21a of the connecting portion 21 and to the receiving groove 25 of the receiving surface 24a. The restricting surface 26a has a pair of surface areas 26x on both sides of the slit 27 in the width direction.

[0019] The cutting tool is further equipped with a movable member 40 rotatably connected to the front end of the receiving part 24. The movable member 40 has a U-shaped base 41 and a pair of elongated flat pressing parts 42 that are connected to a pair of upright walls of the base 41 and face each other in parallel. The distance between the pair of pressing parts 42 (the distance between the pair of upright walls of the base 41) is approximately equal to the width dimension of the receiving part 24. The pair of upright walls of the base 41 are aligned along both side surfaces of the receiving part 24, and a support shaft 2 parallel to the rotation shaft 1 is inserted through the upright walls and the receiving part 24, so that the pressing member 40 is connected to the receiving part 24 rotatably (movably) in the front-rear direction. The rearward facing surfaces of the pair of pressing parts 42 are provided as pressing surfaces 42a that perform the function described below.

[0020] <Cutting tool action> A process for cutting a plastic pipe 100 (a long object to be cut) using the cutting tool having the above configuration will be described with reference to Figures 3 and 4. For the sake of simplicity, the plastic pipe 100 is represented by a circle in Figures 3 and 4. 3, the resin pipe 100 is pushed from the front toward the back (rearward) into the clamping space 28 of the second lever 20. Since the clamping space 28 narrows toward the back, the resin pipe 100 is pressed against the receiving surface 24a and the restricting surface 26a and is firmly clamped with some elastic deformation.

[0021] 4, the movable member 40 is rotated backward so that the resin pipe 100 is firmly pressed by the pair of pressing parts 42. In this way, the resin pipe 100 is firmly held at three points by the receiving surface 24a, the restricting surface 26a, and the pressing surface 42a.

[0022] Next, while firmly pressing the movable member 40 with the fingers, the first lever 10 and the second lever 20 are closed to rotate the cutting blade 30 in the direction of the arrow in Fig. 4. The cutting blade 30 passes through the slit 27 in the restricting portion 26 of the second lever 20 and cuts across the plastic pipe 100, and the cutting edge enters the receiving groove 25 in the receiving surface 24a. In this manner, the cutting operation is completed.

[0023] As described above, since the plastic pipe 100 is held firmly before cutting, the plastic pipe 100 can be well cut at a cutting surface perpendicular to its axis. Moreover, the receiving surface 24a and the restricting surface 26a press the plastic pipe 100 with a pair of surface areas 24x, 26x on both sides of the moving path of the cutting blade 30, and the movable member 40 also presses the plastic pipe 100 with the pressing surfaces 42a of the pair of pressing parts 42 on both sides of the cutting blade 30, so that the plastic pipe 100 can be held more stably and the plastic pipe 100 can be cut more reliably perpendicular to its axis.

[0024] The cutting tool having the above-mentioned configuration is particularly suitable for cutting a composite pipe 100 (resin pipe) for cold and hot water supply shown in FIG. 5. The composite pipe 100 has an inner pipe 101 made of a flexible resin pipe such as a cross-linked polyethylene pipe or a polybutene pipe, and a soft covering pipe 102 made of foamed resin. The covering pipe 102 is made of, for example, a 30-fold expanded polyethylene foam having a thickness of 5 mm to 10 mm. As shown in FIG. 3, the composite pipe 100 is pushed into the clamping space 28, whereby the covering pipe 102 is set in a state where it is crushed by the receiving surface 24a and the restricting surface 26a. Furthermore, the pressing member 40 is rotated to cause the pressing surface 42a to crush the covering pipe 102. As a result, the inner pipe 101 is firmly fixed by the receiving surface 24a, the restricting surface 26a, and the pressing surface 42a, and is not displaced even during the cutting process by the cutting blade 30, and can be cut at a cutting surface perpendicular to the axis.

[0025] When cutting the composite pipe 100 as described above, it is preferable that the length L of the cutting blade 30 is πD / 2 or more so that the cladding pipe 102 can be completely cut without leaving any uncut parts even if the cladding pipe 102 is crushed and flattened, where D is the outer diameter of the cladding pipe 102 (nominal cuttable outer diameter).

[0026] The cutting tool configured as described above can cut resin pipes 100 of different diameters. For example, as shown in Fig. 6, when cutting a resin pipe 100 having a smaller diameter than the resin pipe 100 in Figs. 3 to 5, the resin pipe 100 is pushed to the back of the clamping space 28, and the movable member 40 is rotated further backward, so that it can be firmly held in the same manner as described above.

[0027] <Means for maintaining movable members> In the above-described cutting tool, the movable member 40 is maintained pressed against the plastic pipe 100 by the fingers during cutting, but the pressed state of the movable member 40 may be maintained by a maintaining means 45 provided on the receiving portion 24 of the second lever 20 as shown by imaginary lines in Fig. 6. This maintaining means 45 may include a spring such as a torsion spring that constantly urges the movable member 40 backward. For example, a torsion spring is wound around the protruding end of the support shaft 2, one end of which is engaged with the receiving portion 24, and the other end is engaged with the base portion 41 of the movable member 40. With the movable member 40 rotated forward against the spring, the plastic pipe 100 is pushed from the front into the clamping space 28 to set it in place. When the movable member 40 is released after setting, the force of the spring causes the movable member 40 to press against the plastic pipe 100, and this set state can be maintained.

[0028] The maintaining means 45 may be a friction resistance imparting mechanism that imparts friction resistance between the receiving portion 24 of the second lever 20 and the movable member 40. In this case, after setting the plastic pipe 100 in the clamping space 28, the movable member 40 is rotated backward against the friction resistance of the friction resistance imparting mechanism and pressed against the plastic pipe 100, and then the movable member 40 is released. The movable member 40 maintains its position by the friction resistance. The friction resistance imparting mechanism is configured, for example, by inserting the support shaft 2 into the receiving portion 24 so as not to rotate, fixing support plates to both ends of the support shaft 2, and arranging friction plates and disc springs between the support plates and the side surfaces of the base portion 41 of the movable member 40.

[0029] <Second embodiment> FIG. 7 shows a cutting tool according to a second embodiment of the present invention. In FIG. 7, components corresponding to those in the first embodiment are given the same numbers, and detailed description thereof will be omitted. In this embodiment, the movable member 50 is supported by the receiving portion 24 so as to be linearly slidable in the front-rear direction (the longitudinal direction of the receiving portion 24). More specifically, the movable member 50 has a U-shaped base portion 51 and a pair of pressing portions 52 each connected to a pair of standing walls of the base portion 51. The rear surfaces of the pressing portions 52 are provided as pressing surfaces 52a. A guide groove 29 extending in the longitudinal direction is formed on both side surfaces of the receiving portion 24, and two pins 55 are attached to the pair of standing walls of the base portion 51 of the movable member 50. The tips of these pins 55 are inserted into the guide grooves 29, so that the movable member 50 is slidably supported.

[0030] As in the first embodiment, after the plastic pipe is pushed into the clamping space 28, the movable member 50 is slid backward and the pressing surface 52a presses the plastic pipe. As a result, as in the first embodiment, the plastic pipe can be firmly held at three points, the receiving surface 24a, the regulating surface 26a, and the pressing surface 50a. In this embodiment, a fixing screw 56 is screwed into the base 51 of the movable member 50 as a retaining means, and the fixing screw 55 is screwed into the lower surface of the receiving part 24 at the position where the pressing surface 52a presses the plastic pipe, thereby fixing the movable member 50 and maintaining the pressing position.

[0031] In the second embodiment, the retaining means may be a spring that biases the movable member 50 backward. For example, the spring is a tension coil spring hung between the lower surface of the receiving portion 24 and the base of the movable member 50.

[0032] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. In the first embodiment, when the movable member 40 is to be kept pressed against the resin pipe 100 with the fingers, the movable member 40 may be provided with a protruding pressing tab portion. The receiving surface and the restricting surface may be curved instead of flat. The pressing surface of the movable member may be curved instead of flat, or may be bent. The receiving surface, the regulating surface, and the pressing portion of the movable member may be disposed on only one side of the cutting blade, rather than on both sides.

[0033] A composite pipe that can achieve the effect shown in FIG. 5 may be composed of an inner pipe made of a polybutene pipe, a covering pipe made of a corrugated pipe, and an intermediate layer made of foamed polyurethane. Also, the composite pipe may be composed of an inner pipe made of a cross-linked polyethylene pipe, and a covering pipe made of a corrugated pipe made of foamed resin with an expansion ratio of 1.05 or more. The covering pipe of the composite pipe does not have to be a single layer. For example, it may be a polyethylene foam with a non-foamed layer laminated on the outer periphery, or a thin-walled corrugated pipe with urethane foam laminated on the inner periphery. Even if the covering pipe of a composite pipe does not include a foamed resin, it can achieve the effect of FIG. 5 as long as it can be deformed when pushed into the clamping space.

[0034] When cutting a composite pipe having a covering pipe made of a corrugated pipe which is hard and does not easily deform, the inner pipe can be securely held via the covering pipe, and the inner pipe can be cut well.

[0035] It is not limited to composite pipes, but can also cut resin pipes made of single pipes such as cross-linked polyethylene pipes, polybutene pipes, and polypropylene pipes. It can also cut resin pipes reinforced by compounding with soft metal. The pipe shape can be cylindrical or corrugated. Furthermore, the object to be cut may be a hard PVC pipe, and is not limited to a resin pipe; it may be any long object made of a material with a lower rigidity than the cutting blade. [Industrial Applicability]

[0036] The present invention can be applied to cutting plastic pipes and the like. [Explanation of symbols]

[0037] 1 Rotation axis 10 First Lever 20 Second Lever 24 Receiving Department 24a Receiver 24x surface area 25 Receiving groove 26 Regulatory Department 26a Regulatory aspects 26x surface area 27 Slit 28 Clamping space 30 cutting blade 40 Movable parts 42 Holding part 42a Pressing surface 45 Maintenance means 50 Movable parts 52 Holding part 52a Pressing surface 56 Fixing screw (maintenance means) 100 Plastic pipes, composite pipes (for cutting)

Claims

1. A cutting tool comprising first and second levers rotatably connected to each other by a rotating shaft and having rear portions provided as operating parts, and a cutting blade provided on the first lever, wherein a cutting object is cut by the cutting blade while being received by a receiving part provided on the second lever by bringing the operating parts of the first and second levers closer to each other, A cutting tool characterized in that the second lever is provided with a regulating portion that faces the receiving portion along the movement trajectory of the cutting blade, the receiving portion and the regulating portion respectively have a receiving surface and a regulating surface that face each other, a clamping space for clamping an object to be cut is formed between the receiving surface and the regulating surface, and the clamping space is open at the front and gradually narrows toward the back.

2. 2. The cutting tool according to claim 1, further comprising a movable member on the second lever that is movable forward and backward and presses the cutting object held in the holding space from the front.

3. A receiving groove is formed in the receiving surface to receive the cutting edge of the cutting blade, and the receiving surface has a pair of surface regions on both sides of the receiving groove in the rotation axis direction, The regulating portion has a slit through which the cutting blade passes, and the regulating surface has a pair of surface areas on both sides of the slit in the rotation axis direction, The cutting tool according to claim 2 , wherein the movable member has a pair of pressing portions located on both sides of the receiving portion and the regulating portion in the rotation axis direction.

4. 2. The cutting tool according to claim 1, wherein the second lever is provided with a retaining means for retaining a state in which the movable member presses against the object to be cut.

5. 5. A cutting tool as claimed in claim 4, wherein the retaining means includes a spring which biases the movable member rearwardly.

6. 2. The cutting tool according to claim 1, characterized in that the object to be cut consists of an inner tube and a covering tube covering its outer circumference, and when the outer diameter of the covering tube is D, the cutting blade has a length of πD / 2 or more.

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