Mower

Abstract

To provide a trimming machine capable of suppressing damage to a gear when blades are locked, with a simple structure without increasing weight or cost.SOLUTION: The trimming machine includes: an electric motor 50; a blade drive gear 61 rotationally driven by the electric motor 50; an eccentric cam 62 provided in the gear 61; a pair of blades relatively slidably facing and contacting each other, which are reciprocated by the eccentric cam 62 in relatively opposite directions along a longitudinal direction of the pair of blades, thereby grinding together cutting edges 24 provided in a protruding manner with gaps therebetween in the pair of blades; and a shock absorbing portion 70 provided between a connecting portion 28 connected to the eccentric cam 62 and the cutting edges 24 in each of the blades.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a mower. [Background technology]

[0002] Hedge trimmers, clippers, and other cutting machines used to trim and prune hedges and plants comprise a blade drive gear that is driven to rotate by a drive source inside the main body case, a cam (eccentric cam) consisting of upper and lower eccentric disks mounted on one side of the gear, and a pair of upper and lower blades that are slidably opposed to each other. The eccentric cam moves the long, thin upper and lower blades back and forth along their longitudinal directions in opposite directions (relative to each other), causing the comb-like cutting edges on the blades to rub against each other, thereby performing trimming and pruning (see, for example, Patent Document 1).

[0003] In conventional trimmers, the drive shaft is rotatably supported within the transmission case of the main body case (work machine body), and the upper and lower blades are driven by the crankshaft of an internal combustion engine as the drive source via a centrifugal clutch, causing the upper and lower blades to move back and forth (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-193598 [Patent Document 2] Japanese Patent Application Publication No. 11-009089 Summary of the Invention [Problem to be solved by the invention]

[0005] In a trimmer that employs the above-mentioned clutch mechanism, when the cutting blade gets caught on a thick branch, fence, rebar, or other hard object during trimming or pruning and the blade locks, the engine's rotational force and the impact (large torque) caused by the locking are released by the slippage of the clutch mechanism, so the impact caused by the locking is less likely to be transmitted directly to the gears, minimizing damage to the gears.

[0006] On the other hand, in a trimmer that is electrically driven using an electric motor (hereinafter sometimes simply referred to as a motor) as a drive source, if a lock occurs while trimming or pruning without using a clutch mechanism, the clutch mechanism cannot dissipate the motor's rotational force or the impact (large torque) when the lock occurs, and the impact when the lock occurs is transmitted directly to the gear, which may cause damage to the gear (such as chipped teeth).

[0007] One solution to this problem would be to provide a clutch mechanism, similar to that used in engine-driven vehicles, but this would increase the weight and reduce operability, placing a greater burden on the user and increasing costs.

[0008] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a mower that has a simple configuration and can prevent damage to the gear when the blade locks, without increasing weight or cost. [Means for solving the problem]

[0009] In order to solve the above problem, the trimmer of the present invention basically comprises an electric motor, a blade drive gear that is rotationally driven by the electric motor, an eccentric cam attached to the gear, and a pair of blades that are in relative sliding contact with each other, and the eccentric cam causes the pair of blades to move back and forth in relatively opposite directions along their longitudinal directions, causing the cutting blades that protrude from the pair of blades at a distance to rub against each other, and is characterized in that an impact absorbing part is provided between the connection part of the blade with the eccentric cam and the cutting blades.

[0010] In a preferred embodiment, the trimmer includes a connecting rod connecting the eccentric cam and the blade, and the shock absorbing portion is provided on the blade between the connecting portion with the connecting rod and the cutting edge.

[0011] In another preferred embodiment, the shock absorbing portion may include a weakened portion.

[0012] In another preferred embodiment, the shock absorbing portion may include a slit extending in a direction perpendicular to the direction of reciprocation of the blade.

[0013] In another preferred aspect, the width of the shock absorbing portion including the slit portion in the perpendicular direction may be wider than the width of the blade in the perpendicular direction between the connection portion and the shock absorbing portion and / or the width of the blade in the perpendicular direction between the shock absorbing portion and the cutting edge.

[0014] In another preferred embodiment, the width of the shock absorbing portion including the slit portion in the orthogonal direction may be narrower than the width of the cutting edge protruding from the blade in the orthogonal direction.

[0015] In another preferred embodiment, the slit portion may be provided with a weakened portion.

[0016] In another preferred embodiment, the weakened portion may be formed by at least one of a notch, a notch, a recess, and a groove.

[0017] In another preferred aspect, the slit portion may extend in a direction perpendicular to the reciprocating direction of the blades from an elongated hole into which a member is inserted that holds the pair of blades so that they can move back and forth in relatively opposite directions along their longitudinal direction.

[0018] In another preferred aspect, the slit portion may extend in a direction perpendicular to the reciprocating direction of the blades from a position different from the long hole into which a member that holds the pair of blades so that they can move back and forth in relatively opposite directions along their longitudinal direction is inserted. [Effects of the Invention]

[0019] According to the present invention, it is only necessary to provide an impact absorbing section between the connecting section of the blade and the cutting edge, so that damage to the gear when the blade locks can be prevented with a simple configuration without increasing weight or cost. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a perspective view showing a hedge trimmer according to an embodiment of the present invention. [Figure 2] 1 is a side view showing a hedge trimmer according to an embodiment of the present invention. [Figure 3] 1 is a side cross-sectional view showing a hedge trimmer according to an embodiment of the present invention. [Figure 4] 1 is a bottom view of a hedge trimmer according to an embodiment of the present invention, showing a state in which the bottom plate of the case of the drive transmission mechanism has been removed. FIG. [Figure 5] 10A and 10B are diagrams illustrating the operation of the upper blade and the lower blade due to engagement between the eccentric cam and the movable plate. [Figure 6] 3 is an enlarged bottom view showing a main portion (base end portion) of a lower blade of a hedge trimmer according to one embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The following description will be given using a hedge trimmer, a type of pruning machine, as an example. In this specification, the blade (cutting blade) side is referred to as the front side or tip side, the main body case side as the rear side or base side, the side from which the front handle gripped by the operator protrudes is referred to as the upper side, and the opposite side is referred to as the lower side. However, the up-down, front-rear, left-right directions are set for the convenience of explaining the hedge trimmer of this embodiment, and do not limit the configuration or usage of the hedge trimmer.

[0022] As shown in Fig. 1, the hedge trimmer 1 of this embodiment is a small, handheld cutting implement used for trimming and pruning hedges and plants, and is electrically driven by a battery 100. As shown in Fig. 2, the hedge trimmer 1 comprises an electric motor 50 as a drive source, a blade assembly 20 disposed in front of the electric motor 50, and a main body case 10 that houses the electric motor 50.

[0023] The main body case 10 is a box made of resin, and the top surface is inclined relative to the bottom surface. The top surface of the main body case 10 is inclined downward from the rear side to the front side. In other words, the front part of the main body case 10 is lower than the rear part. The main body case 10 is formed in a roughly triangular shape when viewed from the side.

[0024] A battery mounting section 15 for mounting the battery 100 is provided on the top surface of the main body case 10. The battery mounting section 15 is inclined downward from the rear to the front to match the top surface of the main body case 10.

[0025] Battery 100 is a well-known battery that houses a secondary battery such as a lithium-ion battery in a rectangular parallelepiped case extending in the front-to-rear direction. As shown in Figures 2 and 3, an engagement portion 110 that engages with battery mounting portion 15 protrudes from the rear end of the underside of battery 100.

[0026] When attaching the battery 100 to the battery mounting portion 15, the battery 100 is slid forward from the rear side relative to the battery mounting portion 15, and the lower part of the battery 100 is fitted into the battery mounting portion 15. Then, when the front end of the battery 100 moves to a position where it is supported by the front end of the battery mounting portion 15, the engaging portion 110 of the battery 100 engages with the battery mounting portion 15, and the battery 100 is fixed to the battery mounting portion 15.

[0027] Metallic connection terminals (not shown) are provided on the upper surface of the battery attachment portion 15. The connection terminals are electrically connected to a control board (not shown) and the electric motor 50. When the connection terminals of the battery attachment portion 15 are connected to the connection terminals of the battery 100, power is supplied from the battery 100 to the control board and the electric motor 50.

[0028] When removing the battery 100 from the battery mounting portion 15, the connecting lever 120 (Figure 3) provided at the rear end of the battery 100 is pulled up, which disengages the battery mounting portion 15 from the engagement portion 110, allowing the battery 100 to slide rearward relative to the battery mounting portion 15.

[0029] As shown in Fig. 1, a front handle 30 is provided in front of the main body case 10. The front handle 30 is disposed in front of the battery 100 attached to the battery attachment portion 15. The front handle 30 is formed in a gate shape when viewed from the front, and has left and right vertical portions extending downward from the left and right ends of a horizontal portion extending in the left-right direction, with the lower ends of both vertical portions fixed to the front end of the main body case 10. A front guard 31 is provided between the lower ends of the both vertical portions of the front handle 30. The front guard 31 is formed so as to cover the blade assembly 20 (its base end) from above.

[0030] A rear handle 40 is provided at the rear of the main body case 10. The rear handle 40 is formed with a connecting portion 41 connected to the rear part of the main body case 10, and a grip portion 42 with an opening formed therethrough in the left-right direction. When an operator holds the hedge trimmer 1, the operator inserts his / her hand into the opening of the grip portion 42 to grip the rear handle 40. As shown in FIG. 3 , the connecting portion 41 of the rear handle 40 is connected to the rear surface of the main body case 10 so as to be rotatable about an axis in the front-rear direction. This allows the entire rear handle 40 to be rotatable about an axis in the front-rear direction relative to the main body case 10.

[0031] 1, a trigger lever 43 is provided on the inner periphery of the grip portion 42 of the rear handle 40. The trigger lever 43 is an operating means for rotating the electric motor 50 and driving the blade assembly 20 while being held by an operator. In addition, a lock release lever 44 for unlocking the trigger lever 43 and a power switch 45 are provided on the upper surface of the grip portion 42.

[0032] It should be noted that the shape of the main body case 10, the arrangement and mounting configuration of the battery 100, etc. are not limited to the illustrated example.

[0033] In addition, in the hedge trimmer 1 of this embodiment, power is supplied from the battery 100 to the control board and the electric motor 50, but for example, power may be supplied to the control board and the electric motor 50 from an external power source via a power cord without using the battery 100.

[0034] 2, the blade assembly 20 extends linearly forward relative to the electric motor 50 and protrudes forward from the front end of the main body case 10. The blade assembly 20 is a cutting tool that includes an upper blade 21 and a lower blade 22 made of metal, and a resin cover 23.

[0035] The upper blade 21 and the lower blade 22 are elongated, plate-like blades that are stacked one on top of the other. The upper blade 21 and the lower blade 22 form a pair that abuts on each other and are slidable relative to each other. As shown in FIG. 1, the upper blade 21 and the lower blade 22 are formed with a plurality of cutting edges 24 that protrude in the left-right direction at predetermined intervals along their longitudinal direction. The cover 23 is a protective member that prevents contact between the upper blade 21 and the lower blade 22 and the operator's hands, and covers the top surface of the upper blade 21.

[0036] As shown in FIG. 4 , the upper blade 21 and the lower blade 22 are formed with a required number of elongated holes (longitudinal holes) 25 at predetermined intervals along their longitudinal direction. The length of the elongated holes 25 is set to allow the upper blade 21 and the lower blade 22 to move back and forth. Square cylindrical spacers 26, rectangular in plan view and having circular insertion holes, are slidably inserted into the elongated holes 25 (overlapping vertically) of the upper blade 21 and the lower blade 22. Bolts 27 serving as fastening members are inserted through the circular insertion holes of the square cylindrical spacers 26 (which may include through-holes provided in the cover 23, depending on the longitudinal location) to fasten the upper blade 21 and the lower blade 22. Thus, the upper blade 21 and the lower blade 22 are fastened at predetermined locations along their longitudinal direction while being held slidably relative to each other.

[0037] 3 and 4, connecting portions 28 are formed at the rear end (base end) of the upper blade 21 and the lower blade 22 to be connected to a movable plate 63 (described later). In this embodiment, connecting portions 28 are formed (protruded) as short cylindrical protrusions, and are inserted into openings at the tip end of the movable plate 63 (described later), thereby connecting the upper blade 21 and the lower blade 22 to the movable plate 63. However, the configuration of connecting portions 28, i.e., the connection configuration between the upper blade 21 and the lower blade 22 and the movable plate 63, is not limited to the illustrated example. For example, circular openings may be formed in the upper blade 21 and the lower blade 22 as connecting portions, and cylindrical protrusions formed on the movable plate 63 may be inserted into the openings to connect them.

[0038] 3 and 4, the rear ends of the upper blade 21 and the lower blade 22 are inserted into the main body case 10. The rear ends of the upper blade 21 and the lower blade 22 are connected to the electric motor 50 via a drive transmission mechanism 60.

[0039] The drive transmission mechanism 60 includes a blade drive gear 61, upper and lower eccentric cams (hereinafter simply referred to as cams) 62, 62 provided on the blade drive gear 61, and upper and lower movable plates (also referred to as connecting rods) 63, 63.

[0040] The blade drive gear 61 is a disk-shaped gear with a support shaft 64 protruding vertically from the center. The upper and lower ends of the support shaft 64 are rotatably supported by upper and lower bearings 65, 65 provided inside the main body case 10. In other words, the blade drive gear 61 rotates around the axis of the support shaft 64.

[0041] Upper and lower cams 62, 62 made of eccentric disks protrude from the upper and lower surfaces of the blade drive gear 61. The upper and lower cams 62, 62 are provided at positions eccentric to one side and the other side, respectively, with respect to the center of rotation of the blade drive gear 61 (the center of the support shaft 64). In this embodiment, the upper and lower cams 62, 62 are molded integrally with the gear 61 by machining.

[0042] The upper cam 62 is inserted into and engaged with the opening at the rear end of the upper movable plate 63, and the connecting portion 28 at the rear end of the upper blade 21 is inserted into and connected to the opening at the tip of the upper movable plate 63. The lower cam 62 is inserted into and engaged with the opening at the rear end of the lower movable plate 63, and the connecting portion 28 at the rear end of the lower blade 22 is inserted into and connected to the opening at the tip of the lower movable plate 63.

[0043] In the drive transmission mechanism 60, as the blade drive gear 61 rotates, the upper and lower cams 62, 62 rotate and move, causing the upper and lower movable plates 63, 63 to move back and forth in the front and rear direction, and the upper blade 21 and the lower blade 22 to move back and forth in opposite directions in the front and rear direction (in other words, they move back and forth in opposite directions along their longitudinal directions with a predetermined stroke) (see FIGS. 4 and 5). In other words, the rotational motion of the electric motor 50 is converted into reciprocating motion of the upper blade 21 and the lower blade 22 in the front and rear direction (longitudinal direction) via the upper and lower movable plates 63, 63 of the drive transmission mechanism 60.

[0044] The blade drive gear 61, cams 62, 62, movable plates 63, 63, etc. are housed in a case 66 of the drive transmission mechanism 60. This case 66 has a top plate 67 and a bottom plate 68. The top plate 67 and bottom plate 68 of the case 66 are formed to cover the rear end of the blade assembly 20 from above and below, together with the blade drive gear 61, cams 62, 62, movable plates 63, 63, etc. The blade assembly 20 protrudes forward from the front end of the case 66.

[0045] In this embodiment, a connecting rod type is adopted in which the upper and lower cams 62, 62 are indirectly connected to the upper blade 21 and the lower blade 22 (connection parts 28, 28) via the upper and lower movable plates 63, 63. However, it is of course also possible to adopt a long hole type in which, for example, a long hole (long hole in the left-right direction) is formed as a connection part at the rear end (base end) of the upper blade 21 and the lower blade 22, and the upper and lower cams 62, 62 are inserted into the long hole (connection part) to move the upper blade 21 and the lower blade 22 back and forth in the front-to-back direction. In other words, it is of course also possible to adopt a long hole type in which the upper and lower cams 62, 62 are directly connected to the upper and lower blades 21 and 22 (connection parts).

[0046] The electric motor 50 is installed above the rear of the drive transmission mechanism 60. The electric motor 50 includes a stator 51, an outer rotor 52, an output shaft 53, and a base member .

[0047] A plurality of coils 51a are provided on the stator 51. A base member 54 is provided on the inner periphery of the stator 51, and the lower end of the base member 54 is fixed to a case 66 of the drive transmission mechanism 60 (top plate 67 thereof).

[0048] The output shaft 53 is inserted into a bearing provided on the inner peripheral surface of the base member 54. As a result, the output shaft 53 is rotatably supported by the base member 54. An output gear 53a is provided at the lower end of the output shaft 53. The output gear 53a meshes with a blade drive gear 61 of the drive transmission mechanism 60.

[0049] The outer rotor 52 has a cylindrical peripheral wall 52a that surrounds the outer periphery of the stator 51 and each coil 51a, and a top 52b that closes the upper opening of the peripheral wall 52a. In this embodiment, the outer rotor 52 is made of iron, but the material of the outer rotor as a wheel is not limited. A plurality of magnets 52c are attached to the inner circumferential surface of the peripheral wall 52a.

[0050] The upper end of the output shaft 53 is connected to the center of the top portion 52b of the outer rotor 52. As a result, the outer rotor 52 is rotatably supported by the stator 51, and the output shaft 53 and the outer rotor 52 rotate in conjunction with each other. The rotation axis L of the outer rotor 52 and the output shaft 53 extends in the vertical direction perpendicular to the extension direction (front-rear direction) of the blade assembly 20.

[0051] The outer rotor 52 is formed so that its diameter (horizontal direction) is larger than its length (vertical direction) in the direction of the rotation axis L. In other words, the outer rotor 52 is formed so as to have a flat shape whose width is larger than its height when viewed in the horizontal direction (direction perpendicular to the rotation axis L).

[0052] The outer rotor 52 is rotatably supported by the stator 51 and is connected to the rear end of the blade assembly 20 via a drive transmission mechanism 60. When electricity is applied to each coil 51a of the stator 51 from the battery 100, the outer rotor 52 and the output shaft 53 rotate, and this drive force is transmitted to the blade assembly 20 via the drive transmission mechanism 60, causing the upper blade 21 and the lower blade 22 to reciprocate in opposite directions in the forward and backward directions (see FIGS. 4 and 5). That is, the cams 62, 62 of the drive transmission mechanism 60 cause the pair of elongated upper and lower blades 21 and 22 to reciprocate in opposite directions (relative to each other) along their longitudinal directions, causing the comb-like cutting edges 24 provided on the blades to rub against each other, thereby trimming or pruning hedges or shrubs.

[0053] In a hedge trimmer 1 that is electrically driven using the electric motor 50 of the above configuration as a drive source, if a lock occurs while trimming or pruning without using a clutch mechanism, the clutch mechanism cannot dissipate the rotational force of the motor 50 or the impact (large torque) at the time of locking, and the impact at the time of locking is transmitted directly to the gear 61, which may cause damage to the gear 61 (such as chipped teeth).

[0054] Therefore, in this embodiment, in order to prevent damage to the gear 61 when the blades (upper blade 21, lower blade 22) are locked, an impact absorbing portion 70 is provided between the connection portion 28 of the blades (upper blade 21, lower blade 22) and the cutting edge 24 (more specifically, the cutting edge 24 located closest to the base end or connection portion 28).

[0055] The shock absorbing portion 70 may be provided on both the upper blade 21 and the lower blade 22, or on only one of them. A detailed description will be given below, taking as an example a case where the shock absorbing portion 70 is provided on the lower blade 22.

[0056] The shock absorbing portion 70 is the most vulnerable portion on the lower blade 22, and is a portion that, when locking occurs, suppresses (absorbs) by deformation or breakage the shock or the like that is transmitted to the gear 61 via the movable plate 63, etc. In this embodiment, the shock absorbing portion 70 is configured to include a slit portion 71 and a vulnerable portion 72, as can be seen by referring to FIG. 6 together with FIG. 4.

[0057] The slit portion 71 is formed to extend in the left-right direction (a direction perpendicular to the reciprocating direction). The left-right ends of the slit portion 71 are formed in a generally circular shape that is slightly wider (wider in the front-rear direction) than the central portion. In this embodiment, the left-right width (Ls) of the shock absorbing portion 70, including the slit portion 71, is wider than the left-right width of the lower blade 22. That is, the left-right width (Ls) of the shock absorbing portion 70, including the slit portion 71, is wider than the left-right width (La) of the lower blade 22 between the connecting portion 28 and the shock absorbing portion 70 and / or the left-right width (Lb) of the lower blade 22 between the shock absorbing portion 70 and the cutting edge 24. The left-right width (Ls) of the shock absorbing portion 70, including the slit portion 71, is narrower than the left-right width (Lc) of the cutting edge 24 that protrudes from the lower blade 22 in the left-right direction. In other words, the shock absorbing portion 70 including the slit portion 71 is positioned further inward in the left-right direction than the cutting edge 24 protruding from the lower blade 22, and is formed so as not to protrude further outward in the left-right direction than the cutting edge 24 protruding from the lower blade 22.

[0058] The fragile portions 72 are formed by notches, cutouts, depressions, grooves, etc. In this embodiment, the fragile portions 72 are formed at the left and right ends of the slit portion 71 (in other words, at the portions of the slit portion 71 that are farthest from the center of the lower blade 22).

[0059] With this configuration, when locking occurs during trimming or pruning, the shock absorbing section 70 is deformed by the shock generated when the locking occurs. Furthermore, if the shock generated when the locking occurs cannot be absorbed by deformation of the shock absorbing section 70 (slit section 71) alone, the fragile section 72 (notch, etc.) provided in the shock absorbing section 70 is damaged. As a result, the shock generated when the locking occurs, which is transmitted to the gear 61 via the movable plate 63, etc., can be suppressed (absorbed) by deformation or damage of the shock absorbing section 70.

[0060] Furthermore, in this embodiment, due to installation space limitations, the slits 71 of the shock absorbing unit 70 are formed to extend in the left-right direction from the elongated holes 25 into which the rectangular cylindrical spacers 26 are inserted. However, the slits 71 of the shock absorbing unit 70 may be formed to extend in the left-right direction from a position different from the elongated holes 25 into which the rectangular cylindrical spacers 26 are inserted. For example, in the latter case, if a tensile force acts in the front-rear direction during locking and the shock absorbing unit 70 (the slits 71) is deformed, the elongated holes 25 adjacent to the shock absorbing unit 70 (the slits 71) are deformed to become wider in the left-right direction, thereby achieving the effect that the upper blade 21 and the lower blade 22 can smoothly slide relative to each other (in other words, the sliding of the upper blade 21 and the lower blade 22 is not hindered).

[0061] In this embodiment, the shock absorbing portion 70 is provided at one location between the connecting portion 28 of the blade (upper blade 21, lower blade 22) and the cutting edge 24. However, it goes without saying that the shock absorbing portion 70 may be provided at multiple locations between the connecting portion 28 of the blade (upper blade 21, lower blade 22) and the cutting edge 24. It goes without saying that the shape of the shock absorbing portion 70 is not limited to the example shown in the figures.

[0062] As described above, the hedge trimmer 1 of this embodiment includes an electric motor 50, a blade drive gear 61 that is rotationally driven by the electric motor 50, an eccentric cam 62 provided on the gear 61, and a pair of blades that are in relative slidable contact with each other. The eccentric cam 62 reciprocates the pair of blades in opposite directions relative to each other along their longitudinal directions, causing the cutting edges 24 that protrude from the pair of blades at a distance from each other to rub against each other. The shock absorbing portion 70 is provided between the connection portion 28 of the blade with the eccentric cam 62 (in this embodiment, the connection portion 28 with the movable plate that connects the cam and the blade) and the cutting edge 24 (more specifically, the cutting edge 24 located closest to the base end or the connection portion 28). This allows the shock absorbing portion 70 to deform and absorb shocks that occur when the cutting edge gets caught on a hard object such as a thick branch, fence, or rebar during trimming or pruning and locks the blade (when locked), thereby preventing damage to the gear 61.

[0063] Additionally, the shock absorbing section 70 is provided with a weakened section 72 (such as a notch). As a result, even if an impact that cannot be absorbed by the shock absorbing section 70 is applied, the weakened section 72 (such as a notch) breaks, thereby preventing damage to the gear 61. Furthermore, since the weakened section 72 is located between the connecting section and the cutting edge, the blade will not break at the cutting edge 24, making the blade safer.

[0064] In addition, since blades are usually replacement parts that are replaced when they become worn, even when they are replaced due to deformation or damage as described above, they are easier to replace and the cost can be kept low compared to when gear 61 or the like is replaced due to damage (i.e., there is a large cost benefit).

[0065] The shock absorbing portion 70 also includes a slit portion 71 extending in a direction (short direction) perpendicular to the reciprocating direction (longitudinal direction) of the blade. The width of the shock absorbing portion 70 including the slit portion 71 in the perpendicular direction is wider than the width of the blade in the perpendicular direction between the connecting portion 28 and the shock absorbing portion 70 and / or the width of the blade in the perpendicular direction between the shock absorbing portion 70 and the cutting edge 24. This improves maintainability, for example, by allowing a user to grasp the shock absorbing portion 70 and forcibly slide the blade, thereby making it easier to remove chips adhering between the upper blade 21 and the lower blade 22.

[0066] Furthermore, the width of the shock absorbing part 70 including the slit part 71 in the orthogonal direction is narrower than the width in the left-right direction of the cutting blade 24 protruding in the left-right direction. This makes it less likely that the shock absorbing part 70 will get caught on branches or the like during work, thereby maintaining workability.

[0067] As described above, according to this embodiment, it is only necessary to provide an impact absorbing section 70 between the connecting section of the blade and the cutting edge, so that damage to the gear 61 when the blade locks can be prevented with a simple configuration without increasing weight or cost.

[0068] Although an example of an embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate within the scope of the invention.

[0069] As shown in FIG. 1 , the blade assembly 20 of the hedge trimmer 1 of this embodiment extends linearly forward, with the upper blade 21 and the lower blade 22 configured to reciprocate in the front-to-rear direction; however, the configuration of the blade assembly is not limited thereto. For example, one example of a blade assembly may be a T-shaped blade having a straight portion extending forward from the electric motor 50 and a blade extending left and right at the tip of the straight portion, which is configured to reciprocate left and right. Furthermore, the blade assembly 20 of the hedge trimmer 1 of this embodiment is configured to perform pruning or trimming by causing the upper blade 21 and the lower blade 22 to reciprocate in opposite directions along their longitudinal directions using upper and lower eccentric cams 62, 62 (i.e., a type in which both the upper blade 21 and the lower blade 22 operate). However, it goes without saying that one of the upper blade 21 and the lower blade 22 may not operate. [Explanation of symbols]

[0070] 1 Hedge trimmer 10 Main unit case 15 Battery mounting section 20 Blade Assembly 21 Upper Blade 22 Lower Blade 23 Cover 24 cutting edge 25 slotted hole 26 Square cylindrical spacer 27 volts 28 Connection 30 Front handle 31 Front Guard 40 rear handle 41 Connecting part 42 Gripping part 43 Trigger Lever 44 Lock release lever 45 Power switch 50 Electric motor 60 Drive transmission mechanism 61 Blade drive gear 62 Eccentric cam 63 Movable plate (connecting rod) 64 Spindle 65 bearings 66 cases 67 Top plate 68 Bottom plate 70 Shock absorbing part 71 Slit section 72 Weak part 100 Battery 110 Engagement portion 120 Connecting lever L rotation axis

Claims

1. An electric motor; a blade drive gear that is rotationally driven by the electric motor; an eccentric cam provided on the gear; a pair of blades that are in contact with each other and can slide relative to each other; The eccentric cam reciprocates the pair of blades in opposite directions relative to each other along their longitudinal direction, and the cutting edges of the pair of blades, which are spaced apart in the longitudinal direction and project laterally from both sides of the blades, rub against each other. a shock absorbing portion is provided between a connecting portion of the blade with the eccentric cam and the cutting edge, The shock absorbing portion includes a pair of fin portions that are aligned laterally and extend in opposite directions from both sides of the blade extending in the longitudinal direction, and a slit portion that is elongated in the transverse direction and penetrates the blade in the transverse direction to the pair of fin portions, a width in the lateral direction of the shock absorbing portion including the pair of fin portions and the slit portion is wider than a width in the lateral direction of the blade, The impact absorbing portion constitutes the weakest part of the blade along the longitudinal direction, and absorbs the impact that occurs when the blade locks by compressing the laterally elongated slit portion and deforming in the longitudinal direction.

2. The mower includes a connecting rod connecting the eccentric cam and the blade, 2. The mower according to claim 1, wherein the shock absorbing portion is provided between the cutting edge and a connecting portion of the blade connected to the connecting rod.

3. The trimmer according to claim 1 or 2, characterized in that the shock absorbing portion further comprises a fragile portion that, when the shock is locked, breaks and is transmitted to the gear if the shock cannot be absorbed by deformation of the shock absorbing portion alone.

4. A trimmer described in any one of claims 1 to 3, characterized in that the lateral width of the shock absorbing portion including the pair of fin portions and the slit portion is narrower than the lateral width of the cutting edge protruding laterally from the blade.

5. A trimmer as described in any one of claims 1 to 4, characterized in that the slit portion is provided with a weak portion that absorbs the impact when locked, which is transmitted to the gear by breaking if the impact cannot be fully absorbed by deformation of the impact absorbing portion alone.

6. 6. The trimmer according to claim 5, wherein the weakened portion is formed by at least one of a notch, a cutout, a recess, and a groove.

7. A trimmer as described in Claim 5 or 6, characterized in that the weak portion is the lateral end of the slit portion, and is located at the part of the slit portion that is farthest from the center of the blade.

8. A trimmer described in any one of claims 1 to 7, characterized in that the front-to-back width of the lateral ends of the slit portion is wider than the front-to-back width of the central portion of the slit portion.

9. A trimmer as described in any one of claims 1 to 8, characterized in that the slit portion extends laterally of the blade so as to penetrate laterally through a longitudinally elongated hole into which a member that holds the pair of blades so that they can move back and forth in relatively opposite directions along their longitudinal direction is inserted.

10. A trimmer as described in any one of claims 1 to 8, characterized in that the slit portion extends laterally of the blade from a position that avoids passing laterally through a longitudinally elongated hole into which a member that holds the pair of blades so that they can move back and forth in relatively opposite directions along their longitudinal direction is inserted.

11. A trimmer as described in claim 9 or 10, characterized in that the front-to-back width of the slit portion is narrower than the lateral width of the long hole.

12. A trimmer described in any one of claims 1 to 11, characterized in that the trimmer comprises a main body case from which the pair of blades protrude forward, and a rear handle that is connected to the rear surface of the main body case so as to be freely rotatable around an axis in the front-to-rear direction, and has a trigger lever provided on its inner circumference for driving the pair of blades.

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