Cutting tool

Abstract

To provide a technology capable of preventing a loosening prevention member from falling off from a threaded member.SOLUTION: The cutting tool disclosed in this specification includes a first blade, a second blade that can rotate relative to the first blade, a base material that supports the first blade and the second blade, a head, and a shaft portion that extends from the head at its base end and has a male thread defined therein, in which a screw member that fastens the first blade and the base material together by screwing the male thread into a female thread, a loosening prevention member that is attached to the shaft portion and is pressed by the head to prevent the screw member from loosening, and a falling-off prevention member that is attached to the shaft portion to be adjacent to the loosening prevention member on the tip side of the shaft portion relative to the loosening prevention member and prevents the loosening prevention member from moving from the base end side to the tip side of the shaft portion are provided.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The technology disclosed herein relates to cutting tools. [Background technology]

[0002] Patent Document 1 discloses a cutting tool comprising a first blade, a second blade rotatable relative to the first blade, a base supporting the first blade and the second blade, a head, and a shaft portion extending from the head as a base end and having a male thread defined therein, a screw member fastening the first blade and the base together by screwing the male thread into a female thread, and a loosening prevention member attached to the shaft portion and preventing the screw member from loosening by being pressed by the head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-107440 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a cutting tool such as that disclosed in Patent Document 1, there is a risk that the loosening prevention member will fall off the screw member (specifically, the tip of the shank) when the screw member is removed from the cutting tool. This specification provides a technology capable of preventing the loosening prevention member from falling off the screw member. [Means for solving the problem]

[0005] The cutting tool disclosed in this specification includes a first blade, a second blade that is rotatable relative to the first blade, a base material supporting the first blade and the second blade, a head, and a shank extending from the head at its base end and having a male thread defined therein, and fastens the first blade and the base material to each other by screwing the male thread into a female thread, a loosening prevention member that is attached to the shank and prevents loosening of the screw member by being pressed by the head, and a falling-off prevention member that is attached to the shank so as to be adjacent to the loosening prevention member on the tip side of the shank further than the loosening prevention member, and prevents the loosening prevention member from moving from the base end side to the tip side of the shank.

[0006] According to the above configuration, the screw member is provided with the anti-loosening member that inhibits the loosening inhibitor from moving from the base end side to the tip end side of the shaft portion. This makes it possible to inhibit the anti-loosening member from falling off the screw member.

[0007] In this specification, "loosening of the screw member" specifically means loosening of the screw member when the screw member is tightened. In addition, in this specification, "detachment of the loosening-prevention member" specifically means detachment of the loosening-prevention member when the screw member is removed from the cutting tool. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view of pruning scissors 2 according to the embodiment, seen from above on the front left. [Diagram 2] FIG. 2 is an exploded view showing the components provided on the front side of the pruning scissors 2 according to the embodiment disassembled in the left-right direction. [Diagram 3] 2 is an enlarged view of the front part of the pruning scissors 2 according to the embodiment, seen from the left. [Figure 4] 1 is a cross-sectional view showing the state in which fastening by a lock screw 44 is completed in the pruning scissors 2 according to the embodiment. FIG. [Diagram 5]1 is a view of the internal structure of pruning scissors 2 as viewed from the right when the operating mode of pruning scissors 2 according to the embodiment is the normal mode and the trigger lever 10 is not being pulled. [Figure 6] 1 is a perspective view of the trigger lever 10, gear housing 16, and sensor board 208 of the pruning scissors 2 according to the embodiment, viewed from above on the front right. [Figure 7] 1 is a view of the internal structure of pruning scissors 2 as viewed from the right when the operating mode of pruning scissors 2 according to the embodiment is the normal mode and the trigger lever 10 is being pulled. FIG. [Figure 8] 1 is a perspective view of the movable blade 8 and blade holder 38 of pruning scissors 2 according to an embodiment, viewed from above and behind on the left. [Figure 9] 1A to 1C are diagrams illustrating a state in which the open position of the movable blade 8 of the pruning scissors 2 according to the embodiment is switched between a first open position P1 and a second open position P2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Representative and non-limiting embodiments of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Additionally, the additional features and inventions disclosed can be used separately or together with other features and inventions to provide further improved cutting tools.

[0010] In addition, the combinations of features and steps disclosed in the following detailed description are not essential for implementing the present invention in the broadest sense, but are specifically described only to illustrate representative embodiments of the present invention. Furthermore, the various features of the following representative embodiments and the various features described in the claims do not have to be combined in the exact manner of the embodiments described herein or in the order listed in order to provide additional and useful embodiments of the present invention.

[0011] All features described in the specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0012] In one or more embodiments, the loosening inhibiting member may include a first surface facing a base end side of the shank and a second surface facing a tip end side of the shank. A shape of the first surface when viewed from the base end side of the shank and a shape of the second surface when viewed from the tip end side of the shank may be different from each other.

[0013] If the shape of the first surface when viewed from the base end side of the shaft portion and the shape of the second surface when viewed from the tip side of the shaft portion are the same, the loosening prevention function of the loosening prevention member is not significantly impaired even if the orientations of the first surface and the second surface are interchanged. In the above configuration, the shape of the first surface when viewed from the base end side of the shaft portion and the shape of the second surface when viewed from the tip side of the shaft portion are different from each other. Therefore, if the orientations of the first surface and the second surface are interchanged, the loosening prevention function of the loosening prevention member may be impaired. Here, if the loosening prevention member falls off from the screw member, the orientations of the first surface and the second surface may be interchanged when the user attaches the fallen loosening prevention member to the screw member. This may impair the loosening prevention function of the loosening prevention member. Therefore, in the above configuration, it is particularly desirable to prevent the loosening prevention member from falling off. According to the above configuration, the loosening prevention member can be prevented from falling off the screw member, so that the effect of preventing the loosening prevention member from falling off is significantly achieved.

[0014] In one or more embodiments, the loosening inhibiting member may include a plate portion that expands along a generally truncated cone shape with a diameter increasing toward the tip side of the shaft portion, and a plurality of teeth that are provided along at least one of an inner periphery and an outer periphery of the plate portion and protrude in the direction in which the plate portion expands. The falling-off inhibiting member may be a generally annular elastic member.

[0015] In this specification, the member that presses the loosening suppression member between the head and the mating member is also called the mating member. In the above configuration, the loosening suppression member has multiple teeth that bite into at least one of the head and the mating member to generate friction torque for suppressing loosening of the screw member. However, if the plate portion is excessively crushed by the force (so-called axial force) with which the head and the mating member press the plate portion, the multiple teeth will not bite into at least one of the head and the mating member. As a result, the friction torque for suppressing loosening of the screw member is reduced, and the loosening suppression function of the loosening suppression member is reduced. According to the above configuration, the dropout suppression member attached adjacent to the plate portion enters the inside of the plate portion (i.e., the inside of the approximately truncated cone shape). The dropout suppression member that enters the inside of the plate portion supports the inner surface of the plate portion in the axial direction. Therefore, it is possible to suppress the plate portion from being excessively crushed by the axial force, and therefore it is possible to suppress the multiple teeth from not biting into at least one of the head and the mating member. This makes it possible to improve the friction torque for preventing the loosening of the screw member, and to improve the loosening prevention function of the loosening prevention member.

[0016] In one or more embodiments, the first blade or the base material may include a through hole through which the shaft portion passes, a contact surface against which the loosening prevention member abuts, and a recess provided along the peripheral portion of the through hole for retracting at least a portion of the anti-fall-out member inward beyond the abutment surface.

[0017] The falling-off inhibiting member is pressed in the axial direction and deformed by being sandwiched between the loosening inhibiting member and the mating member. If the falling-off inhibiting member is excessively deformed, the falling-off inhibiting member may break. According to the above configuration, the first blade or the base material corresponding to the mating member has an abutment surface that abuts against the loosening inhibiting member and a recess that retracts at least a part of the falling-off inhibiting member further inward than the abutment surface. The abutment surface and the recess make the space between the loosening inhibiting member and the mating member relatively large. Therefore, the amount of deformation of the falling-off inhibiting member when the falling-off inhibiting member is sandwiched between the loosening inhibiting member and the mating member can be reduced. Therefore, excessive deformation of the falling-off inhibiting member can be suppressed, and therefore the falling-off inhibiting member can be suppressed from breaking.

[0018] In one or more embodiments, the recess may smoothly interface with the abutment surface.

[0019] If the connection portion between the recess and the abutment surface does not have a smooth shape (e.g., a sharp shape), there is a risk that the load acting on the fall-off prevention member will become locally excessive when the fall-off prevention member abuts against the connection portion. This may result in the fall-off prevention member breaking. According to the above configuration, since the connection portion between the recess and the abutment surface has a smooth shape (e.g., a rounded shape or a chamfered shape), it is possible to prevent the load acting on the fall-off prevention member from becoming locally excessive when the fall-off prevention member abuts against the connection portion. This makes it possible to prevent the fall-off prevention member from breaking.

[0020] In one or more embodiments, the cutting tool may include a motor shaft coupled to the second blade and an electric motor for rotating the motor shaft. Driving the electric motor may cause the first blade and the second blade to rotate relative to each other to perform a cutting action.

[0021] In a manual cutting tool in which a cutting operation (i.e., rotation of the second blade relative to the first blade) is performed by a force applied by a user, components other than the first blade and the second blade are relatively inexpensive. Therefore, when the first blade and the second blade are worn out, it is common to replace the entire cutting tool. Therefore, in a manual cutting tool, it is considered that the frequency with which the first blade is removed from the base material (i.e., the frequency with which the screw member is removed from the cutting tool) is low. In contrast, the above cutting tool is an electric cutting tool in which a cutting operation is performed by power from an electric motor. In an electric cutting tool, components other than the first blade and the second blade (e.g., an electric motor, etc.) are relatively expensive. Therefore, when the first blade and the second blade are worn out, only the first blade and the second blade may be replaced. That is, the first blade and the second blade may be replaced. Therefore, in an electric cutting tool, it is expected that the frequency with which the first blade is removed from the base material (i.e., the frequency with which the screw member is removed from the cutting tool) is high, and therefore it is particularly desirable to prevent the loosening suppression member from falling off. According to the above configuration, in the electric cutting tool, the loosening prevention member can be prevented from falling off the screw member, which significantly reduces the effect of preventing the loosening prevention member from falling off.

[0022] In one or more embodiments, the fall-off prevention member may be attached to the shaft portion in a state in which the fall-off prevention member is spread out in a radial direction of the shaft portion.

[0023] If there is play between the fall-off prevention member and the shaft portion, the fall-off prevention member may rattle relative to the shaft portion. If the fall-off prevention member rattles relative to the shaft portion, the fall-off prevention member and the shaft portion may collide with each other, which may cause the fall-off prevention member (or the shaft portion) to wear out. With the above configuration, no play occurs between the fall-off prevention member and the shaft portion, so the fall-off prevention member is prevented from rattling relative to the shaft portion. This makes it possible to prevent wear of the fall-off prevention member (or the shaft portion).

[0024] In one or more embodiments, when viewed from the base end side of the shaft portion, the fall-off prevention member may be hidden by the loosening prevention member.

[0025] If the fall-off prevention member is not hidden by the loosening prevention member when viewed from the base end side of the shaft, the design of the cutting tool may be impaired. According to the above configuration, the fall-off prevention member is hidden by the loosening prevention member when viewed from the base end side of the shaft, thereby improving the design of the cutting tool.

[0026] (Example) As shown in Fig. 1, the cutting tool of this embodiment is pruning scissors 2. The pruning scissors 2 are mainly used for cutting tree branches, etc. The pruning scissors 2 can be held and carried by a user in one hand.

[0027] The pruning scissors 2 include a housing 4, a fixed blade 6, a movable blade 8, a trigger lever 10, and a battery pack B. As will be described in detail later, the pruning scissors 2 executes a cutting operation by rotating the movable blade 8 relative to the fixed blade 6 using power supplied from the battery pack B in response to pulling the trigger lever 10. The fixed blade 6 and the movable blade 8 are made of metal (e.g., iron). The battery pack B contains a rechargeable secondary battery such as a lithium ion battery.

[0028] The housing 4 includes a left housing 12, a right housing 14, a gear housing 16, and a cover housing 18. The left housing 12, the right housing 14, the gear housing 16, and the cover housing 18 are all formed of plastic. The left housing 12 and the right housing 14 are fixed to each other by screws (not shown). The gear housing 16 is supported by the left housing 12 and the right housing 14. The cover housing 18 is fixed to the left housing 12 and the right housing 14 by screws (not shown). The housing 4 is provided with a grip portion 20 to be gripped by a user, a protection portion 22 to protect the trigger lever 10, and a battery attachment portion 24 to detachably attach the battery pack B.

[0029] 1 to 9, in the longitudinal direction of the gripping portion 20, the direction from the battery mounting portion 24 to the fixed blade 6 and the movable blade 8 is defined as the front direction, and the direction from the fixed blade 6 and the movable blade 8 to the battery mounting portion 24 is defined as the rear direction. The direction perpendicular to the front-rear direction and along the rotation axis of the movable blade 8 is defined as the left-right direction. In the left-right direction, the direction from the movable blade 8 to the fixed blade 6 is defined as the left direction, and the direction from the fixed blade 6 to the movable blade 8 is defined as the right direction. The direction perpendicular to the front-rear direction and the left-right direction is defined as the up-down direction.

[0030] An operation unit 26 is provided at the upper rear part of the housing 4. The operation unit 26 includes a power switch 28 for switching the main power supply on / off, an adjustment switch 30 (described in detail below), and the like. In addition, a display unit 32 is provided at the upper front part of the housing 4. The display unit 32 includes an LED (not shown) for displaying the on / off state of the main power supply, the remaining battery charge state of the battery pack B, and the like.

[0031] As shown in FIG. 2, the pruning scissors 2 further include a co-tightening bolt 36, a blade holder 38, a connecting pin 40, a co-tightening nut 42, a lock screw 44, a lock plate 46, and an O-ring 48. In this embodiment, the central axis of the co-tightening bolt 36 (specifically, the cylindrical portion 54) is illustrated as "axis A1". The central axis of the connecting pin 40 is illustrated as "axis A2". The central axis of the lock screw 44 (specifically, the shaft portion 80) is illustrated as "axis A3". The axes A1, A2, and A3 each extend along the left-right direction.

[0032] The co-fastening bolt 36 is formed with, from the left, a male thread portion 50, a fitting portion 52, and a cylindrical portion 54. The co-fastening bolt 36 is a so-called stepped bolt. The fitting portion 52 has a shape corresponding to a fitting hole 56 provided in the gear housing 16.

[0033] The blade holder 38 has a first through hole 58 and a second through hole 60 provided in front of the first through hole 58. The first through hole 58 rotatably receives the cylindrical portion 54 of the co-fastening bolt 36. Therefore, the blade holder 38 is rotatable around the axis A1. The right portion of the connecting pin 40 is inserted into the second through hole 60. The connecting pin 40 is fixed to the blade holder 38 while being inserted into the second through hole 60. In addition, a first cylindrical portion 62 protruding leftward from the periphery of the first through hole 58 and a bevel gear 64 are formed on the left surface of the blade holder 38.

[0034] The movable blade 8 has a third through hole 66 into which the first cylindrical portion 62 of the blade holder 38 is inserted, and a fourth through hole 68 into which the left portion of the connecting pin 40 is inserted. The movable blade 8 is constrained by the blade holder 38 with respect to the axes A1 and A2. In other words, the movable blade 8 is fixed to the blade holder 38 with respect to the front-rear and up-down directions. This allows the movable blade 8 to rotate integrally with the blade holder 38 around the axis A1.

[0035] The fixed blade 6 has a fifth through hole 70 and a sixth through hole 72 provided behind the fifth through hole 70. A second cylindrical portion 74 protruding rightward from the right surface of the gear housing 16 is inserted into the fifth through hole 70. A female thread 76 is provided on the inner surface of the sixth through hole 72.

[0036] The co-tightening nut 42 has a female thread portion 78 corresponding to the male thread portion 50 of the co-tightening bolt 36. The co-tightening bolt 36 and the co-tightening nut 42 fasten the blade holder 38, the movable blade 8, and the fixed blade 6 to the gear housing 16 by screwing the male thread portion 50 into the female thread portion 78. Specifically, the co-tightening bolt 36 and the co-tightening nut 42 restrain the blade holder 38, the movable blade 8, and the fixed blade 6 in the left-right direction. The user can adjust the force (hereinafter simply referred to as "tightening force") that tightens the gear housing 16, the fixed blade 6, the movable blade 8, and the blade holder 38 in the left-right direction by tightening (or loosening) the co-tightening nut 42 to the co-tightening bolt 36. If the tightening force is too weak, the gap between the fixed blade 6 and the movable blade 8 will expand, and the sharpness of the pruning scissors 2 may decrease. On the other hand, if the tightening force is too strong, a large resistance force is generated in the movable blade 8 when the movable blade 8 is rotated relative to the fixed blade 6. This may increase the load on the electric motor 204 (see FIG. 5) that rotates the movable blade 8, or may cause the battery pack B to consume more power quickly. Therefore, there is an appropriate range of values ​​for the tightening torque of the co-tightening nut 42 to the co-tightening bolt 36.

[0037] The lock screw 44 includes a shaft portion 80 and a head portion 82. The shaft portion 80 is provided with a male thread 84 corresponding to the female thread 76 provided on the fixed blade 6. The lock screw 44 is made of metal (e.g., iron). The lock plate 46 and the O-ring 48 are attached around the shaft portion 80 of the lock screw 44. The lock plate 46 can also be called a washer. The lock plate 46 is made of metal (e.g., iron). The O-ring 48 is made of rubber (e.g., NBR). The O-ring 48 is disposed on the tip side of the shaft portion 80 relative to the lock plate 46. The inner diameter of the O-ring 48 in a state where no load is applied to the O-ring 48 is smaller than the outer diameter of the shaft portion 80. Therefore, the O-ring 48 is attached to the shaft portion 80 in a state where it is pushed outward by the shaft portion 80 in the radial direction of the axis A3. The outer diameter of the O-ring 48 in this state is larger than the inner diameter of the lock plate 46. Therefore, when the lock plate 46 moves toward the tip side of the shaft portion 80, the lock plate 46 comes into contact with the O-ring 48 and is prohibited from moving further toward the tip side of the shaft portion 80. This prevents the lock plate 46 from falling off the shaft portion 80 when, for example, the tip of the shaft portion 80 is pointed downward. Also, as shown in FIG. 3, the lock plate 46 includes a plate body 86 and a plurality of teeth 88 provided along the outer periphery of the plate body 86. When viewed from the left, the O-ring 48 (see FIG. 2) is hidden by the lock plate 46.

[0038] As shown in Fig. 2, the gear housing 16 is provided with a seventh through hole 90 behind the fitting hole 56, through which the shaft portion 80 of the lock screw 44 can pass. When the male thread 84 is screwed into the female thread 76 of the fixed blade 6 with the shaft portion 80 of the lock screw 44 passing through the seventh through hole 90, the fixed blade 6 is fastened to the gear housing 16, as shown in Fig. 4. As a result, the fixed blade 6 is fixed to the gear housing 16.

[0039] As shown in Fig. 3, a contact surface 92 for receiving the co-locking nut 42 and the lock plate 46 is provided on the left surface of the gear housing 16. The contact surface 92 is a flat surface that is approximately perpendicular to the left-right direction. A plurality of teeth 94 corresponding to the plurality of teeth 88 of the lock plate 46 are formed on the outer periphery of the co-locking nut 42. For simplification, the plurality of teeth 94 of the co-locking nut 42 are not shown in the drawings other than Figs. 3 and 4.

[0040] When the fixed blade 6 is fixed to the gear housing 16, the lock plate 46 is fastened with the lock screw 44 in a state where the teeth 88 of the lock plate 46 are engaged with the teeth 94 of the co-locking nut 42. When fastening with the lock screw 44 is complete, the lock plate 46 is prohibited from rotating relative to the gear housing 16, and therefore the co-locking nut 42 which engages with the lock plate 46 is also prohibited from rotating. This prevents the co-locking nut 42 from loosening, for example, and causes the fastening force to change unintentionally.

[0041] When it is desired to adjust the fastening force by fastening (or loosening) the co-fastening nut 42, it is necessary to first loosen the lock screw 44 and then remove the lock screw 44. When removing the lock screw 44, moving the lock plate 46 to the left along the axis A3 releases the engagement between the co-fastening nut 42 and the lock plate 46. This allows the co-fastening nut 42 to rotate, making it possible to adjust the fastening force.

[0042] As shown in FIG. 4, the gear housing 16 is provided along the periphery of the seventh through hole 90 and has a recess 96 recessed to the right of the abutment surface 92. The recess 96 has a bottom surface 96a and an inclined surface 96b. The bottom surface 96a is connected to the periphery of the seventh through hole 90 and spreads out substantially parallel to the abutment surface 92. The inclined surface 96b smoothly connects between the bottom surface 96a and the abutment surface 92. The inclined surface 96b gradually approaches the bottom surface 96a as it approaches the axis A3. The inclined surface 96b gradually approaches the abutment surface 92 as it moves away from the axis A3. The depth of the recess 96 (specifically, the bottom surface 96a) relative to the abutment surface 92 is approximately half the left-right width of the O-ring 48 in an unloaded state.

[0043] A left surface 98 of the lock plate 46 (plate body 86 and multiple teeth 88) and a right surface 100 of the lock plate 46 (plate body 86 and multiple teeth 88) each have a generally conical surface whose diameter increases toward the tip side of the shaft portion 80. In other words, the lock plate 46 (plate body 86 and multiple teeth 88) has a shape that follows a generally truncated cone shape whose diameter increases toward the tip side of the shaft portion 80.

[0044] When fastening by the lock screw 44 is complete, a left corner 102 of the plate body 86 abuts against the head 82 of the lock screw 44. A right corner 104 of the plate body 86 (which can also be considered an individual corner of the multiple teeth 88) abuts against the abutment surface 92. In this state, the left corner 102 bites into the head 82, and the right corner 104 bites into the abutment surface 92. This generates a friction torque that suppresses rotation of the head 82 relative to the abutment surface 92, thereby suppressing loosening of the lock screw 44.

[0045] Furthermore, when fastening by the lock screw 44 is complete, the O-ring 48 is pressed between the bottom surface 96a of the recess 96 and the right surface 100 of the plate body 86. In this state, the O-ring 48 biases the right surface 100 of the plate body 86 leftward against the bottom surface 96a (i.e., the gear housing 16). This prevents the lock plate 46 from being crushed by the head 82 of the lock screw 44. In other words, the lock plate 46 is prevented from being deformed in the axial direction of the axis A3.

[0046] The lock screw 44 receives an axial force from an elastic restoring force from the lock plate 46 and an elastic restoring force from the O-ring 48. That is, both the lock plate 46 and the O-ring 48 are members that apply an axial force to the lock screw 44. From the viewpoint of applying an axial force to the lock screw 44, it is desirable that the O-ring 48 be able to appropriately crush and secure a contact area with other members (the gear housing 16 and the lock plate 46). On the other hand, from the viewpoint of durability, it is desirable that the O-ring 48 has a certain degree of resistance to crushing. In view of this, for example, it is desirable that the tensile strength of the O-ring 48 is within a range of 10 MPa to 30 MPa. The tensile strength of the O-ring 48 here is used as one of the indicators of the resistance to crushing of the O-ring 48. The tensile strength of the O-ring 48 in this embodiment is about 20 MPa.

[0047] As shown in FIG. 5, the pruning scissors 2 further include a control device 202, an electric motor 204, a power transmission mechanism 206, and a sensor board 208. The control device 202, the electric motor 204, the power transmission mechanism 206, and the sensor board 208 are accommodated inside the housing 4. The control device 202 is disposed at the rear of the housing 4. The electric motor 204 is disposed in front of the control device 202. The longitudinal direction of the electric motor 204 is aligned with the front-rear direction. The power transmission mechanism 206 is disposed in front of the electric motor 204. The sensor board 208 is disposed at the front of the housing 4.

[0048] The control device 202 includes a memory, a CPU, and the like. The control device 202 is electrically connected to each of the operation unit 26, the display unit 32, the electric motor 204, and the sensor board 208. In addition, when the battery pack B is attached to the battery attachment portion 24, the control device 202 and the battery pack B are electrically connected. The control device 202 controls the operation of the pruning scissors 2 according to a predetermined program stored in the memory. For example, the control device 202 switches between a state in which power supply from the battery pack B to the electric motor 204 is permitted and a state in which power supply is cut off according to the on / off state of the main power source. In addition, the control device 202 controls the display unit 32 to display the on / off state of the main power source, the state of the remaining battery charge of the battery pack B, and the like.

[0049] The electric motor 204 is, for example, a brushless motor. When power is supplied to the electric motor 204, the electric motor 204 rotates a motor shaft (not shown) extending along the front-rear direction.

[0050] The power transmission mechanism 206 includes a planetary gear mechanism (not shown) connected to the motor shaft (not shown), and a gear shaft 212 connected to the planetary gear mechanism. The planetary gear mechanism reduces the rotation of the motor shaft and transmits it to the gear shaft 212. That is, the planetary gear mechanism functions as a reducer. The gear shaft 212 is supported by a bearing (not shown) provided inside the gear housing 16 so as to be rotatable around an axis along the front-rear direction. A bevel gear 214 corresponding to the bevel gear 64 (see FIG. 2) formed on the left side of the blade holder 38 is formed on the front part of the gear shaft 212. A part of the gear shaft 212 (bevel gear 214) meshes with the bevel gear 64 of the blade holder 38 through an opening 218 formed on the right side of the gear housing 16. The bevel gears 64, 214 convert the rotation of the gear shaft 212 into the rotation of the blade holder 38 and the movable blade 8 around the axis A1. Therefore, when the electric motor 204 is driven, power is transmitted to the movable blade 8 via the motor shaft, the planetary gear mechanism, the gear shaft 212, and the bevel gears 64 and 214. This causes the movable blade 8 to rotate.

[0051] As shown in FIG. 6, the trigger lever 10 includes a base 220, an operating portion 222 extending rearward and downward from the vicinity of the rear end of the base 220, and a protruding portion 224 protruding upward from the upper surface of the base 220. A magnet 226 is fixed to the right surface of the base 220. A rotating pin 228 extending in the left-right direction is inserted in the center of the base 220. The rotating pin 228 is rotatably supported by the gear housing 16. This allows the trigger lever 10 to rotate around the rotating pin 228. As shown in FIG. 5, the operating portion 222 is a portion of the trigger lever 10 exposed to the outside of the housing 4 and is a portion operated by the user. In addition, a compression spring 230 is attached around the protruding portion 224. The compression spring 230 enters a recess (not shown) provided on the lower surface of the gear housing 16. This allows the compression spring 230 to be held between the gear housing 16 and the trigger lever 10. The compression spring 230 biases the operating portion 222 of the trigger lever 10 downward relative to the gear housing 16. Therefore, when the user is not operating the operating portion 222, the trigger lever 10 is held in the position shown in Fig. 5. When the user pulls the operating portion 222, the trigger lever 10 rotates clockwise as viewed from the right, against the biasing force of the compression spring 230. When the user pulls the operating portion 222 to its maximum, the position of the trigger lever 10 becomes the position shown in Fig. 7.

[0052] As shown in FIG. 6, the sensor board 208 is fixed to the gear housing 16 by screws 208a and 208b. The sensor board 208 extends in a direction substantially perpendicular to the left-right direction. The sensor board 208 is provided with a first magnetic sensor 232, a second magnetic sensor 234, and a third magnetic sensor 236. The first magnetic sensor 232 is disposed near the lower end of the sensor board 208. The second magnetic sensor 234 is disposed rearward and above the first magnetic sensor 232. The third magnetic sensor 236 is disposed above the second magnetic sensor 234. The first magnetic sensor 232, the second magnetic sensor 234, and the third magnetic sensor 236 can detect magnetism and output the detection results to the control device 202 (see FIG. 5). The detection results output to the control device 202 indicate, for example, the strength of the magnetism and the direction of the magnetic field.

[0053] When the trigger lever 10 is pulled, the position of the magnet 226 changes relative to the sensor board 208. For example, when the trigger lever 10 is in the position shown in FIG. 5, the magnet 226 (see FIG. 6) is on the left side of the sensor board 208 and faces a portion where the first magnetic sensor 232 (see FIG. 6) is provided. When the trigger lever 10 is in the position shown in FIG. 7, the magnet 226 is on the left side of the sensor board 208 and faces a portion where the second magnetic sensor 234 (see FIG. 6) is provided. When the position of the magnet 226 changes, the magnetism detected by the first magnetic sensor 232, the second magnetic sensor 234, and the third magnetic sensor 236 fluctuates. Therefore, the control device 202 (see FIG. 5) can determine whether the trigger lever 10 is pulled based on the output from at least one of the first magnetic sensor 232, the second magnetic sensor 234, and the third magnetic sensor 236 (the first magnetic sensor 232 in this embodiment). Furthermore, the control device 202 can determine the amount of pulling of the trigger lever 10 based on the output from at least one of the first magnetic sensor 232, the second magnetic sensor 234, and the third magnetic sensor 236.

[0054] As shown in FIG. 8, a mounting hole 38a is formed on the left surface of the blade holder 38 between the first cylindrical portion 62 and the bevel gear 64. A magnet 38b is attached to the mounting hole 38a. When the movable blade 8 and the blade holder 38 rotate around the axis A1, the position of the magnet 38b changes with respect to the sensor board 208. For example, when the blade holder 38 is in the position shown in FIG. 5, the magnet 38b (see FIG. 8) is in a position facing the second magnetic sensor 234 (see FIG. 6). When the blade holder 38 is in the position shown in FIG. 7, the magnet 38b is in a position facing the third magnetic sensor 236 (see FIG. 6). When the position of the magnet 38b changes, the magnetism detected by the first magnetic sensor 232, the second magnetic sensor 234, and the third magnetic sensor 236 fluctuates. Therefore, the control device 202 (see Figure 5) can determine the rotation angle of the movable blade 8 (i.e., the position of the movable blade 8 relative to the housing 4) based on the output from at least one of the first magnetic sensor 232, the second magnetic sensor 234, and the third magnetic sensor 236 (in this embodiment, the second magnetic sensor 234 and the third magnetic sensor 236).

[0055] (Normal mode of Pruning Shears 2) The following describes the normal operation of the pruning scissors 2. The normal operation here refers to, for example, immediately after the main power is turned on or when the user performs cutting work. In this embodiment, the operation mode of the pruning scissors 2 at this time is called the normal mode.

[0056] As shown in FIG. 5, when the trigger lever 10 is not pulled, the control device 202 drives the electric motor 204 to hold the movable blade 8 in an open position (also called an open position) relative to the fixed blade 6. When the trigger lever 10 is pulled from this state, the control device 202 drives the electric motor 204 to close the movable blade 8 relative to the fixed blade 6 according to the amount of pulling of the trigger lever 10. Specifically, the control device 202 rotates the movable blade 8 relative to the fixed blade 6 by an amount of rotation according to the amount of pulling of the trigger lever 10. As shown in FIG. 7, when the trigger lever 10 is pulled to the maximum, the movable blade 8 is held in a position (also called a closed position) closed relative to the fixed blade 6. When the pulling operation of the trigger lever 10 is released from this state, the control device 202 drives the electric motor 204 to return the movable blade 8 to the open position. In this way, the user can cause the pruning scissors 2 to perform a cutting operation by pulling the trigger lever 10.

[0057] As shown in Fig. 9, the control device 202 (see Fig. 5) switches the open position of the movable blade 8 between a first open position P1 and a second open position P2 that is closer to the first open position P1 in response to a first operation (e.g., a short press operation) on the adjustment switch 30 (see Fig. 1). This allows the user to select an appropriate opening position depending on the thickness of the object to be cut. Note that the open position is not limited to the first open position P1 and the second open position P2, and may be switched to another position.

[0058] (Pruning Shears 2 cutting depth fine adjustment mode) When the second operation (long press operation) of the adjustment switch 30 (see FIG. 1) is performed, the control device 202 switches the operation mode of the pruning scissors 2 to a cutting depth fine adjustment mode for finely adjusting the cutting depth by the fixed blade 6 and the movable blade 8. The cutting depth here means the width of the overlapping portion of the fixed blade 6 and the movable blade 8 in the circumferential direction of the axis A1 when the movable blade 8 is in the closed position. If the cutting depth is shallow, there is a risk that the fixed blade 6 and the movable blade 8 will not be able to completely cut the object to be cut. Although not shown, in the cutting depth fine adjustment mode, the control device 202 deepens the cutting depth each time the trigger lever 10 is pulled. When the trigger lever 10 is pulled a predetermined number of times, the control device 202 returns the cutting depth to the original depth. This allows the user to adjust the cutting depth to an appropriate depth by pulling the trigger lever 10. It should be noted that when a third operation (short press or long press) is performed on the adjustment switch 30 in the cutting depth fine adjustment mode, the control device 202 switches the operation mode of the pruning scissors 2 to the normal mode.

[0059] (Modification) The cutting tool may be a pair of manual pruning shears. For example, the cutting tool may have a pair of grips that are relatively rotatable, each of which has a blade similar to the fixed blade 6 or the movable blade 8 fixed thereto. In this case, the grip and the blade may be fixed to each other by fastening the blade to the grip with a lock screw 44. One of the grip and the blade may have an internal thread 76 that corresponds to the external thread 84 of the lock screw 44. The other of the grip and the blade may have an abutment surface 92 or a recess 96.

[0060] The shape of the lock plate 46 may be changed as appropriate. For example, the lock plate 46 may be formed in a substantially circular plate shape. The lock plate 46 may also be formed symmetrically.

[0061] A member other than the lock plate 46 may be attached to the lock screw 44 as a member that prevents the lock screw 44 from loosening. For example, a toothed washer, a wave washer, a cup washer, etc. may be attached to the lock screw 44 as a member that prevents the lock screw 44 from loosening.

[0062] A member other than O-ring 48 may be attached to lock screw 44 as a member that prevents lock plate 46 from falling off. For example, a ring-shaped member (e.g., a rubber band) having a different shape from O-ring 48 may be attached to lock screw 44 as a member that prevents lock plate 46 from falling off.

[0063] The gear housing 16 does not necessarily have to have the recess 96 .

[0064] The inclined surface 96b of the recess 96 does not have to be smoothly connected between the bottom surface 96a and the contact surface 92. That is, the inclination angle of the inclined surface 96b may vary discretely between the bottom surface 96a and the contact surface 92.

[0065] The female thread 76 may be provided in the seventh through hole 90 instead of the sixth through hole 72. In this case, the male thread 84 of the lock screw 44 may pass through the sixth through hole 72 and be screwed into the female thread 76 provided in the seventh through hole 90. When fastening by the lock screw 44 is completed, the fixed blade 6 may be sandwiched between the head 82 of the lock screw 44 and the gear housing 16.

[0066] The materials used for each component of the pruning shears 2 (e.g., the housing 4, the fixed blade 6, the movable blade 8, the lock screw 44, the lock plate 46, and the O-ring 48) may be changed as appropriate. For example, the housing 4 may be made of a metal such as aluminum. For example, each of the fixed blade 6, the movable blade 8, the lock screw 44, and the lock plate 46 may be made of a metal other than iron. For example, the O-ring 48 may be made of rubber such as SBR, Si, or SR. Furthermore, the O-ring 48 may be made of an elastomer instead of rubber.

[0067] The operation mode of the pruning scissors 2 is not limited to the normal mode and the cutting depth fine adjustment mode, and may be switched to other modes.

[0068] The pruning shears 2 may be provided with a power supply cable connectable to an external power source instead of the battery attachment section 24. The external power source may be a commercial power source or a portable power source device. The power source device may be a device to which a plurality of battery packs B can be attached, or may be a device capable of supplying power from the plurality of battery packs B to the pruning shears 2.

[0069] (Correspondence) As described above, in one or more embodiments, the pruning scissors 2 (an example of a cutting tool) include a fixed blade 6 (an example of a first blade), a movable blade 8 (an example of a second blade) that is rotatable relative to the fixed blade 6, a gear housing 16 (an example of a base material) that supports the fixed blade 6 and the movable blade 8, a head 82, and a shaft portion 80 that extends from the head 82 as a base end and has a male thread 84 defined therein, and a lock screw 44 (an example of a screw member) that fastens the fixed blade 6 and the gear housing 16 to each other by screwing the male thread 84 into the female thread 76, a lock plate 46 (a loosening prevention member) that is attached to the shaft portion 80 and is pressed by the head 82 to prevent the lock screw 44 from loosening, and an O-ring 48 (an example of a falling-off prevention member) that is attached to the shaft portion 80 so as to be adjacent to the lock plate 46 on the tip side of the shaft portion 80 relative to the lock plate 46, and prevents the lock plate 46 from moving from the base end side to the tip side of the shaft portion 80.

[0070] According to the above configuration, the O-ring 48 that prevents the lock plate 46 from moving from the base end side to the tip end side of the shaft portion 80 is provided on the lock screw 44. This prevents the lock plate 46 from falling off the lock screw 44.

[0071] In one or more embodiments, the lock plate 46 includes a left surface 98 (an example of a first surface) facing the base end side of the shaft portion 80, and a right surface 100 (an example of a second surface) facing the tip end side of the shaft portion 80. The shape of the left surface 98 when viewed from the base end side of the shaft portion 80 is different from the shape of the right surface 100 when viewed from the tip end side of the shaft portion 80.

[0072] If the shape of the left surface 98 when viewed from the base end side of the shaft portion 80 and the shape of the right surface 100 when viewed from the tip side of the shaft portion 80 are the same, the loosening prevention function of the lock plate 46 is not significantly impaired even if the orientations of the left surface 98 and the right surface 100 are interchanged. In the above configuration, the shape of the left surface 98 when viewed from the base end side of the shaft portion 80 and the shape of the right surface 100 when viewed from the tip side of the shaft portion 80 are different from each other. Therefore, if the orientations of the left surface 98 and the right surface 100 are interchanged, the loosening prevention function of the lock plate 46 may be impaired. Here, if the lock plate 46 falls off from the lock screw 44, the orientations of the left surface 98 and the right surface 100 may be interchanged when the user attaches the fallen lock plate 46 to the lock screw 44. This may impair the loosening prevention function of the lock plate 46. Therefore, in the above configuration, it is particularly desirable to prevent the lock plate 46 from falling off. According to the above configuration, the lock plate 46 can be prevented from falling off the lock screw 44, and therefore the effect of preventing the lock plate 46 from falling off is significantly exhibited.

[0073] In one or more embodiments, the lock plate 46 includes a plate body 86 (an example of a plate portion) that expands along a generally truncated cone shape with a larger diameter toward the tip side of the shaft portion 80, and a plurality of teeth 88 that are provided along the outer periphery (an example of at least one of the inner periphery and the outer periphery) of the plate body 86 and protrude in the expanding direction of the plate body 86. The O-ring 48 is a generally annular rubber member (an example of an elastic member).

[0074] In the above configuration, the lock plate 46 has a plurality of teeth 88 that bite into the gear housing 16 (an example of a mating member) in order to generate friction torque for suppressing loosening of the lock screw 44. However, if the plate body 86 is excessively crushed by the force (so-called axial force) with which the head 82 and the gear housing 16 press the plate body 86, the plurality of teeth 88 will no longer bite into the gear housing 16. As a result, the friction torque for suppressing loosening of the lock screw 44 is reduced, and the loosening suppression function of the lock plate 46 is reduced. According to the above configuration, the O-ring 48 attached adjacent to the plate body 86 enters the inside of the plate body 86 (i.e., the inside of the approximately truncated cone shape). The right surface 100 (an example of the inner surface of the plate portion) of the plate body 86 is supported in the axial direction by the O-ring 48 that enters the inside of the plate body 86. Therefore, the plate body 86 can be prevented from being excessively crushed by the axial force, and therefore the plurality of teeth 88 can be prevented from no longer biting into the gear housing 16. This makes it possible to improve the friction torque for preventing the lock screw 44 from loosening, and to improve the function of the lock plate 46 in preventing loosening.

[0075] In one or more embodiments, the fixed blade 6 or the gear housing 16 includes a seventh through hole 90 (an example of a through hole) through which the shaft portion 80 passes, an abutment surface 92 against which the lock plate 46 abuts, and a recess 96 provided along the periphery of the seventh through hole 90, which retracts approximately half of the entire O-ring 48 (an example of at least a portion of the anti-fall-out member) inward from the abutment surface 92.

[0076] The O-ring 48 is pressed in the axial direction by being sandwiched between the lock plate 46 and the gear housing 16, and is deformed. If the O-ring 48 is deformed excessively, the O-ring 48 may break. According to the above configuration, the gear housing 16 has an abutment surface 92 that abuts against the lock plate 46, and a recess 96 that retracts approximately half of the entire O-ring 48 inward from the abutment surface 92. The abutment surface 92 and the recess 96 make the space between the lock plate 46 and the gear housing 16 relatively large. Therefore, the amount of deformation of the O-ring 48 when the O-ring 48 is sandwiched between the lock plate 46 and the gear housing 16 can be reduced. Therefore, the excessive deformation of the O-ring 48 can be suppressed, and therefore the O-ring 48 can be suppressed from breaking.

[0077] In one or more embodiments, the recess 96 smoothly interfaces with the abutment surface 92 .

[0078] If the connecting portion between the recess 96 and the abutment surface 92 does not have a smooth shape, there is a risk that the load acting on the O-ring 48 will become locally excessive when the O-ring 48 abuts on the connecting portion. This may cause the O-ring 48 to break. According to the above configuration, since the connecting portion between the recess 96 and the abutment surface 92 has a smooth shape, it is possible to prevent the load acting on the O-ring 48 from becoming locally excessive when the O-ring 48 abuts on the connecting portion. This makes it possible to prevent the O-ring 48 from breaking.

[0079] In one or more embodiments, the pruning shears 2 include a motor shaft coupled to the movable blade 8 and an electric motor 204 that rotates the motor shaft. By driving the electric motor 204, the fixed blade 6 and the movable blade 8 are rotated relative to each other to perform a cutting action.

[0080] The pruning scissors 2 perform a cutting operation by power from the electric motor 204. In the pruning scissors 2, components other than the fixed blade 6 and the movable blade 8 (for example, the electric motor 204, etc.) are relatively expensive. For this reason, when the fixed blade 6 and the movable blade 8 wear out, only the fixed blade 6 and the movable blade 8 may be replaced. In other words, the fixed blade 6 and the movable blade 8 may be replaced. Therefore, in the pruning scissors 2, it is expected that the fixed blade 6 will be removed from the gear housing 16 frequently (i.e., the lock screw 44 will be removed from the pruning scissors 2 frequently), so it is particularly desirable to prevent the lock plate 46 from falling off. According to the above configuration, in the pruning scissors 2, it is possible to prevent the lock plate 46 from falling off the lock screw 44. Therefore, the effect of preventing the lock plate 46 from falling off is significantly exhibited.

[0081] In one or more embodiments, the O-ring 48 may be attached to the shaft portion 80 in a state in which it is spread out radially of the shaft portion 80 .

[0082] If there is play between the O-ring 48 and the shaft portion 80, the O-ring 48 may rattle relative to the shaft portion 80. If the O-ring 48 rattles relative to the shaft portion 80, the O-ring 48 and the shaft portion 80 may collide with each other, which may result in the O-ring 48 (or the shaft portion 80) being worn out. With the above configuration, no play occurs between the O-ring 48 and the shaft portion 80, so rattling of the O-ring 48 relative to the shaft portion 80 is suppressed. This makes it possible to suppress wear of the O-ring 48 (or the shaft portion 80).

[0083] In one or more embodiments, the O-ring 48 may be hidden by the locking plate 46 when viewed from the proximal end of the shaft 80 .

[0084] If the O-ring 48 is not hidden by the lock plate 46 when viewed from the base end side of the shaft portion 80, it may impair the design of the pruning scissors 2. According to the above configuration, the O-ring 48 is hidden by the lock plate 46 when viewed from the base end side of the shaft portion 80, so the design of the pruning scissors 2 can be improved. [Explanation of symbols]

[0085] 2: Pruning shears 4: Housing 6: Fixed blade 8: Movable blade 10: Trigger lever 12: Left housing 14: Right side housing 16: Gear housing 18: Cover housing 20: Grip part 22:Protective part 24: Battery mounting section 26: Operation unit 28: Power switch 30: Adjustment switch 32: Display unit 36: Co-tightening bolt 38: Blade holder 38a: Mounting hole 38b: Magnet 40: Connecting pin 42: Co-tightening nut 44: Lock screw 46: Lock plate 48: O-ring 50: Male thread 52: Fitting part 54: Cylindrical part 56: Fitting hole 58: First through hole 60: Second through hole 62: First cylindrical section 64: Bevel gear 66: 3rd through hole 68: 4th through hole 70: 5th through hole 72: 6th through hole 74: Second cylindrical section 76: Female thread 78: Female thread 80: Shaft 82:Head 84: Male thread 86: Plate body 88: Multiple teeth on the lock plate 90: 7th through hole 92: Contact surface 94: Multiple teeth of a co-locking nut 96: Recess 96a: Bottom 96b: Inclined surface 98: Left side of lock plate 100: Right side of the lock plate 102: Left corner of plate body 104: Right corner of plate body 202: Control device 204: Electric motor 206: Power transmission mechanism 208: Sensor board 208a : Screw 208b : Screw 212: Gear shaft 214: Bevel gear 218: Opening 220: Base 222:Operation unit 224:Protrusion 226: Magnet 228: Rotating pin 230: Compression spring 232: First magnetic sensor 234: Second magnetic sensor 236: Third magnetic sensor B: Battery pack

Claims

1. A first blade; a second blade that is rotatable relative to the first blade; a substrate supporting the first blade and the second blade; a screw member including a head portion and a shaft portion extending from the head portion as a base end and having a male thread defined therein, the male thread being threadedly engaged with a female thread to fasten the first blade and the base material together; a loosening prevention member attached to the shank and pressed by the head to prevent the screw from loosening; a fall-off prevention member attached to the shaft portion adjacent to the loosening prevention member, on the tip side of the shaft portion relative to the loosening prevention member, and which prevents the loosening prevention member from moving from the base end side to the tip side of the shaft portion.

2. The loosening suppression member is a first surface facing a base end side of the shaft portion; a second surface facing the tip side of the shaft portion, The cutting tool according to claim 1 , wherein the shape of the first surface when viewed from the base end side of the shank is different from the shape of the second surface when viewed from the tip end side of the shank.

3. The loosening suppression member is a plate portion that expands along a generally truncated cone shape with a diameter increasing toward the tip side of the shaft portion; a plurality of teeth provided along at least one of an inner periphery and an outer periphery of the plate portion and protruding in a direction in which the plate portion widens; The cutting tool according to claim 1 or 2, wherein the fall-off prevention member is a substantially annular elastic member.

4. The first blade or the base material is a through hole through which the shaft portion passes; a contact surface with which the loosening inhibiting member comes into contact; The cutting tool according to claim 1 , further comprising: a recess provided along a periphery of the through hole, the recess allowing at least a portion of the fall-off suppression member to retreat inward from the contact surface.

5. The cutting tool of claim 4 , wherein the recess is in a smooth connection with the abutment surface.

6. a motor shaft connected to the second blade; an electric motor that rotates the motor shaft, The cutting tool of claim 1 , wherein the first blade and the second blade are rotated relative to each other by driving the electric motor to perform a cutting action.

7. The cutting tool according to claim 1 , wherein the fall-off prevention member is attached to the shank in a state where the fall-off prevention member is expanded in a radial direction of the shank.

8. The cutting tool according to claim 1 , wherein the stopper member is hidden by the loosening restricting member when viewed from the base end side of the shaft portion.

Images