JP2012010665A - Trimmer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a trimmer trimming branches and leaves with good trimming efficiency.SOLUTION: This trimmer is such that an eccentric cam rotates 45 degrees by the time that a condition that an upper cutting blade and a lower cutting blade are superposed on each other (the pitch distance is P, and the rotation angle is 0 degree) becomes a condition that both the blades separate relatively for a distance L, and when the eccentric cam 4 further rotates to bring a rotation angle to about 155 degrees, the pitch distance is L, and when the eccentric cam further rotates about 25 degrees from about 155 degrees to bring the rotation angle to 180 degrees, the upper cutting blade and the lower cutting blade move relatively for a distance L and are superposed on each other (the pitch distance is 0, and the rotation angle is 180 degrees). In other words, the shape of the eccentric cam and the engagement part is so set that the movement speed of the upper blade and the lower blade becomes fast just before performing trimming action, and the movement speed of the upper blade and the lower blade becomes slow just after starting to move from an initial position.

Description

  The present invention relates to a trimming machine for trimming branches and leaves.

  In a conventional trimming machine, a mechanism for reciprocating the trimming blade by a long hole formed in the trimming blade and an eccentric cam connected to an engine or the like is used. For example, the moving speed of the two cutting blades that form a comb shape in the trimming machine described in Patent Document 1 changes along a sine curve as shown in FIG.

Japanese Patent Laid-Open No. 60-149312

  However, when the moving speed of the cutting blade changes along the sine curve as described above, the moving speed of the cutting blade becomes too fast, and there is a case where the branches and leaves cannot sufficiently enter the comb-like portion. It was. For this reason, there has been a problem that uncut leaves of branches and leaves are generated. Therefore, an object of the present invention is to provide a trimming machine that trims more branches and leaves and leaves no branches or leaves.

  In order to solve the above-described problems, the present invention provides a drive source, an output shaft that outputs power from the drive source, and rotates in response to the output of the output shaft, and reciprocating rotational motion transmitted from the output shaft. The first cam blade having a plurality of first cutting blades, the plurality of second cutting blades, and the first cutting blade and the second cutting blade are mutually connected. A second trimming blade that trims an object together with the first trimming blade when approaching, and at least one of the first trimming blade and the second trimming blade has the eccentric cam An engaging portion that engages with the eccentric cam is provided. When the engaging portion engages with the eccentric cam, the first cutting blade and the second cutting blade relatively reciprocate, and the eccentric cam Is a first angle between the state where the first cutting edge and the second cutting edge overlap and the state where the first cutting edge and the second cutting edge are separated by a predetermined distance. Rotating, and the eccentric cam is moved by a predetermined distance from a state where the first cutting edge and the second cutting edge are separated from each other, and the first cutting edge and the second cutting edge overlap each other And the shape of the eccentric cam and the engaging portion is set so that the first angle is larger than the second angle. Provide a machine.

  In the trimming machine configured as described above, the first trimming blade and the second trimming blade reciprocate once during one rotation of the eccentric cam, and the first trimming blade and the second trimming blade The blade is disposed at the initial position when the eccentric cam is rotated by 0 degrees, is disposed at the first position when the eccentric cam is rotated by 180 degrees, and the second position when the eccentric cam is rotated by 360 degrees. The first cutting edge and the second cutting edge overlap each other at the initial position, the first position, and the second position, and the shapes of the eccentric cam and the engaging portion are , In any case between the initial position and the first position, and between the first position and the second position, the first angle is greater than the second angle. Is preferably set to be large.

  In the trimming machine configured as described above, the engagement portion includes a first engagement portion provided on the first trimming blade and a second engagement portion provided on the second trimming blade, The eccentric cam engages with the first engaging portion and the second engaging portion, respectively, and moves the first cutting blade and the second cutting blade in directions opposite to each other. preferable.

  In the trimming machine having the above-described configuration, the eccentric cam has a contact point that is farthest from the rotation center in the outer periphery of the eccentric cam, and the engaging portion includes the first cutting blade and the second cutting blade. Between the state where the first cutting edge and the second cutting edge are separated from each other by a predetermined distance, the portion that contacts the contact point is the first cutting edge and the second cutting edge. Formed by a gentler curve than the portion in contact with the contact point between the state where the cutting edge is separated from the state where the first cutting edge and the second cutting edge overlap each other by moving the predetermined distance It is preferable that

  In the trimming machine having the above-described configuration, the engaging portion includes the first cutting edge and the second cutting edge in a state where the first cutting edge and the second cutting edge of the engaging portion overlap each other. It is preferable that the portion that contacts the contact point until the blade is separated from the blade by a predetermined distance is formed so as to substantially follow the trajectory through which the contact point passes when the eccentric cam rotates.

  In the trimming machine having the above-described configuration, the engaging portion moves the predetermined distance from a state where the first cutting edge and the second cutting edge are separated from each other and moves the first cutting edge and the second cutting edge. It is preferable that the portion that comes into contact with the contact point before the blades overlap each other is provided closer to the rotation center of the eccentric cam than the locus.

  In the trimming machine having the above-described configuration, the engagement portion is shaped so as to be fitted to the outer periphery of the eccentric cam in a state in which the first cutting blade and the second cutting blade are rotated 90 degrees from the overlapping state. It is preferable to have.

  In the trimming machine having the above-described configuration, the engagement portion has an axis extending through the rotation center of the eccentric cam and extending in parallel with the direction of the reciprocating motion, and is a substantially point-symmetric curve with respect to an arbitrary point on the axis. Is preferably defined by:

  The trimming machine configured as described above further includes a biasing unit that biases one of the engagement portion and the eccentric cam toward the other and maintains the engagement of the engagement portion and the eccentric cam. It is preferable.

  The eccentric cam is engaged between the state where the first cutting edge and the second cutting edge overlap and the state where the first cutting edge and the second cutting edge are separated from each other by a predetermined distance. The portion that contacts the joint moves the predetermined distance from the state where the first cutting edge and the second cutting edge are separated from each other, and the first cutting edge and the second cutting edge overlap each other. It is preferable that the curved line is formed with a gentler curve than the portion in contact with the engaging portion until the state.

  In order to solve the above-described problems, the present invention provides a drive source, an output shaft that outputs power from the drive source, a rotation that receives the output of the output shaft, and rotates that is transmitted from the output shaft. An eccentric cam that converts to reciprocating motion, a first trimming blade having a plurality of first cutting edges, a plurality of second cutting edges, the first cutting edge and the second cutting edge, A second trimming blade that trims an object together with the first trimming blade when they are close to each other, and the relative when the first trimming blade and the second trimming blade are separated from each other A trimming machine characterized in that the speed is lower than the relative speed when approaching.

  According to such a configuration, since the shape of the eccentric cam and the engaging portion is set so that the first angle is larger than the second angle, the first cutting edge and the second cutting edge are set. You can slowly spread between the blades. Therefore, more branches and leaves can be allowed to enter between the first cutting edge and the second cutting edge to prevent uncut residue, and the working efficiency and usability of the operator can be improved.

  Further, since the first cutting blade and the second cutting blade overlap each other twice while the eccentric cam makes one rotation, the cutting operation is performed twice while each of the first cutting blade and the second cutting blade reciprocates once. It can be performed.

  Further, the eccentric cam engages with the first engaging portion and the second engaging portion, respectively, and moves the first cutting blade and the second cutting blade in directions opposite to each other. Compared with the case where only one of the blade and the second trimming blade is moved, when the first cutting blade and the second cutting blade overlap and separate from each other, according to the rotation of the eccentric cam The distance for moving the first cutting blade and the second cutting blade can be set in half.

  According to the trimming machine of the present invention, more branches and leaves can be trimmed, and unleaved leaves and branches can be prevented.

Side surface sectional drawing of the trimming machine which concerns on embodiment of this invention. The top view of the trimming machine which concerns on embodiment of this invention. Sectional drawing which shows the eccentric cam periphery of the trimming machine which concerns on embodiment of this invention. Explanatory drawing which shows the engaging part of the cutting blade of the trimming machine which concerns on embodiment of this invention. Explanatory drawing which shows the position of the eccentric cam and cutting blade in case the rotation angle of the eccentric cam of the trimming machine which concerns on embodiment of this invention is 0 degree | times. Explanatory drawing which shows the position of the eccentric cam and cutting blade in case the rotation angle of the eccentric cam of the trimming machine which concerns on embodiment of this invention is 30 degree | times. Explanatory drawing which shows the position of the eccentric cam and cutting blade in case the rotation angle of the eccentric cam of the trimming machine which concerns on embodiment of this invention is 45 degree | times. Explanatory drawing which shows the position of the eccentric cam and cutting blade in case the rotation angle of the eccentric cam of the trimming machine which concerns on embodiment of this invention is 90 degree | times. Explanatory drawing which shows the position of the eccentric cam and cutting blade in case the rotation angle of the eccentric cam of the trimming machine which concerns on embodiment of this invention is 180 degree | times. Explanatory drawing which shows the position of the eccentric cam and cutting blade in case the rotation angle of the eccentric cam of the trimming machine which concerns on embodiment of this invention is 210 degree | times. Explanatory drawing which shows the position of the eccentric cam and the cutting blade in case the rotation angle of the eccentric cam of the trimming machine which concerns on embodiment of this invention is 270 degree | times. Explanatory drawing which shows the relationship between the rotation angle of the eccentric cam of the trimming machine which concerns on embodiment of this invention, and the pitch distance of a trimming blade. Explanatory drawing which shows the position of the eccentric cam and cutting blade in case the rotation angle of the eccentric cam which concerns on the modification of the trimming machine which concerns on embodiment of this invention is 0 degree | times. Explanatory drawing which shows the position of the eccentric cam and trimming blade in case the rotation angle of the eccentric cam which concerns on the modification of the trimming machine which concerns on embodiment of this invention is 90 degree | times. Explanatory drawing which shows the position of the eccentric cam and trimming blade in case the rotation angle of the eccentric cam which concerns on the modification of the trimming machine which concerns on embodiment of this invention is 180 degree | times.

  Hereinafter, the trimming machine 1 which concerns on embodiment of this invention is demonstrated based on FIG. 1 thru | or FIG. A trimming machine 1 shown in FIG. 1 is mainly composed of a housing 2, a prime mover unit 3, an eccentric cam 4, and two trimming blades 5, and is a tool for trimming branches and the like with the trimming blade 5. is there. In the following description, the front end side of the cutting blade 5 is the front side, the motor unit 3 side is the upper side with respect to the cutting blade 5, the extending direction of the cutting blade 5 is the front-rear direction, and the front-rear direction on the surface where the cutting blade 5 extends A direction orthogonal to the width direction is described as the width direction.

  The housing 2 is connected to a casing 21 containing the prime mover unit 3, a main housing 22 that supports the casing 21, a handle portion 23 connected to a rear end portion of the main housing 22, and a front end portion of the main housing 22. And a protective cover 24. The casing 21 is assembled to the main housing 22. As shown in FIG. 2, a fuel tank 36 that stores fuel to be supplied to an engine 31 described later is provided outside the casing 21.

  The main housing 22 is disposed below the casing 21 and supports the prime mover 3, the eccentric cam 4, and the cutting blade 5. A rotation shaft 22 </ b> B serving as a rotation center of the eccentric cam 4 is provided between the output shaft 35 and the cutting blade 5 in the main housing 22.

  The handle portion 23 includes an engine 31 described later and a throttle 23A that is connected via a throttle cable (not shown) and adjusts the output of the engine 31. The protective cover 24 is provided with a substantially U-shaped auxiliary handle 24 </ b> A whose lower side is open. The operator can perform the trimming work in a stable posture by gripping the handle portion 23 and the auxiliary handle 24A.

  The prime mover unit 3 mainly includes an engine 31, a flywheel 32, a centrifugal clutch 33, a coil 34, and an output shaft 35. The engine 31 is a two-cycle engine that outputs a constant speed rotational force according to a value specified by the throttle 23A, and includes a cylinder 31A, a piston 31B that reciprocates in the cylinder 31A, and a connecting rod connected to the piston 31B. 31C, a crank 31D that converts the reciprocating motion of the connecting rod 31C into a rotational motion, and a crankcase 31E that accommodates the crank 31D in cooperation with the cylinder 31A. The cylinder 31A is provided with an ignition plug for igniting the cylinder bore, and the crank 31D is provided with a crankshaft 31F that outputs rotational force.

  The flywheel 32 has a substantially disc shape, and is mounted so as to rotate coaxially with the crankshaft 31F on the upper side of the engine 31 so that the substantially disc-shaped central axis coincides with the central axis of the crankshaft 31F. Has been. A magneto 32 </ b> A is provided at a position on the outer periphery of the flywheel 32 and close to the coil 34. Further, the inner peripheral portion of the flywheel 32 is configured in a fan shape, and cooling air is blown to the engine 31 as the flywheel 32 rotates.

  The centrifugal clutch 33 is connected to the crankshaft 31F on the upper side of the flywheel 32 and connected to the output shaft 35 at the lower end thereof. When the rotational speed of the crankshaft 31F is equal to or lower than a predetermined rotational speed, the centrifugal clutch 33 rotates to the output shaft 35. This is a known device that transmits rotation to the output shaft 35 when the rotation speed of the crankshaft 31F becomes greater than a certain rotation speed.

  The coil 34 is disposed at a position in the vicinity of the flywheel 32, and when the flywheel 32 rotates, the magnet 32 </ b> A crosses the vicinity of the coil 34. When magneto 32A crosses the vicinity of coil 34, an induced electromotive force is generated in coil 34 to ignite the spark plug.

  The output shaft 35 is interposed between the engine 31 and the eccentric cam 4, is rotatably supported by a bearing 22 </ b> A provided in the main housing 22, and is driven to rotate at a constant speed by the engine 31. A gear portion 35 </ b> A is provided at the lower end portion of the output shaft 35. The output shaft 35 has an upper end connected to the centrifugal clutch 33 and a lower end engaged with the eccentric cam 4 via the gear portion 35A.

  As shown in FIG. 3, the eccentric cam 4 has a substantially disc shape, includes a first cam portion 41 and a second cam portion 42, and is provided between the cutting blade 5 and the output shaft 35. ing. The eccentric cam 4 is formed with a through hole 4a having a diameter substantially larger than the outer diameter of the rotating shaft 22B. The rotating shaft 22B is inserted through the through hole 4a, and the eccentric cam 4 is supported by the main housing 22 so as to be rotatable about the rotating shaft 22B. A gear portion 4A is provided on the substantially disc-shaped outer periphery of the eccentric cam 4, and the eccentric cam 4 rotates the output shaft 35 when the gear portion 4A meshes with the gear portion 35A of the output shaft 35. Rotates at a constant angular velocity under force.

  The first cam portion 41 is provided on the upper surface side of the eccentric cam 4, and the second cam portion 42 is provided on the lower surface side of the eccentric cam 4. The first cam portion 41 and the second cam portion 42 have a cylindrical shape and are set to have a phase difference of 180 degrees from each other. When the eccentric cam 4 rotates, the first cam portion 41 and the second cam portion 42 rotate eccentrically about the rotation shaft 22B. The first cam portion 41 is engaged with an upper blade 51 described later, and the second cam portion 42 is engaged with a lower blade 52 described later. When the eccentric cam 4 is engaged with the upper blade 51 and the lower blade 52, the rotational motion transmitted from the output shaft 35 is converted into the reciprocating motion of the cutting blade 5.

  The cutting blade 5 includes an upper blade 51 disposed on the upper side and a lower blade 52 disposed on the lower side. The upper blade 51 and the lower blade 52 move in directions opposite to each other in the front-rear direction, and cut an object such as a branch or leaf when cutting blades 53A and 56A (described later) come close to each other and overlap in the vertical direction. The upper blade 51 and the lower blade 52 are made of metal, are formed in a plate shape extending in the front-rear direction, and have substantially the same shape. As shown in FIGS. 5A to 5G, the upper blade 51 includes a blade portion 53, an engagement portion 54 that is engaged with the first cam portion 41, and the blade portion 53 and the engagement portion. 54 and a connecting portion 55 located between them.

  The blade portion 53 is located at the front portion of the upper blade 51, and has a plurality of cutting blades 53A that protrude in one direction and the other in the width direction and form a saw blade shape along the front-rear direction. Yes. The plurality of cutting blades 53A protrude alternately in the width direction at one side and the other, and are configured such that the interval between the adjacent cutting blades 53A is a distance P / 2. In other words, the cutting blades 53A protruding in one width direction are provided at a distance P, and the cutting blade 53A protrudes from the other side in the middle of the adjacent cutting blades 53A on one side. The cutting blade 53A has blades on both side surfaces thereof. The cutting blade 53A allows dead leaves to enter between the cutting blade 53A and the cutting blade 56A when separated from the cutting blade 56A described later, and when the cutting blade 53A overlaps with the cutting blade 56A, the cutting blade 53A and the cutting blade 56A Cut the branches and leaves located between. The blade portion 53 has a plurality of long holes 53a each having a long diameter with the distance P as the front-rear direction and a small diameter slightly larger than the diameter of a bolt 59A described later.

  The engaging portion 54 has a substantially elliptical shape in which the front-rear direction has a short diameter and the width direction has a long diameter, and is positioned in the rear portion of the upper blade 51. As shown in FIG. 4, an engagement hole 54 a is formed in the engagement portion 54, and the eccentric cam 4 is disposed so that the first eccentric cam portion 41 engages in the engagement hole 54 a. The engaging portion 54 has an axis AX that extends in the front-rear direction through the rotation center of the eccentric cam 4 (the center of the rotation shaft 22B). The inner peripheral surface of the engaging portion 54 is defined by the curves C1 and C2. The curves C1 and C2 have a shape that is substantially point-symmetric with respect to an arbitrary point on the axis AX. When the first cam portion 41 rotates while engaging with the engaging portion 54 in the engaging hole 54a, the upper blade 51 is urged and reciprocates in the front-rear direction.

  Here, the point that is farthest from the rotation center (rotation shaft 22B) in the outer periphery of the eccentric cam 4 is the contact point 41A, and the point that is closest to the rotation shaft 22B is the proximity point 41B. FIG. 4 shows a state in which the eccentric cam 4 is arranged at the initial position when the rotation angle of the eccentric cam 4 is 0 degree. At this time, in the eccentric cam 4, the contact point 41A contacts the point where the starting point of the curve C1 intersects the axis AX in the engaging portion 54, and the contact point 41A intersects the end point of the curve C1 and the axis AX. It is arranged so that it touches the point. The eccentric cam 4 rotates counterclockwise at a constant angular velocity.

  The curve C1 has curves C11 and C12. A curved line C11 is a portion where the contact point 41A contacts between the engaging portion 54 and the rotation angle of the eccentric cam 4 from 0 degree to 45 degrees, and the contact point when the eccentric cam 4 is rotated. 41A is a curve substantially along a trajectory through which 41A passes. A curved line C12 is an arc having a radius of curvature substantially equal to the radius of the first cam portion 41. Therefore, the inner peripheral surface defined by the curve C12 of the engaging portion 54 has a shape that fits to the outer periphery of the eccentric cam 4, and is closer to the rotation center of the first cam portion 41 than the locus of the contact point 41A. It is provided to do. In other words, the curvature radius of the curve C11 is larger than the curvature radius of the curve C12, and the curve C11 is a gentler curve than the curve C12. Further, the curves C11 and C12 are set so that at least two points on the outer periphery of the first cam portion 41 are always in contact with the inner peripheral surface of the engaging portion 54.

  The curve C2 is a curve having the end point of the curve C1 as the start point and the start point of the curve C1 as the end point, and the curve C1 is arranged symmetrically with respect to one point on the axis. The curve C2 has a curve C21 corresponding to the curve C11 and a curve C22 corresponding to the curve C12.

  As shown in FIGS. 5A to 5G, the connecting portion 55 extends in the front-rear direction and is located between the blade portion 53 and the engaging portion 54. Although the lower blade 52 is the same as the upper blade 51 and the description thereof is omitted, a blade portion 56 having a plurality of cutting blades 56A and having a long hole 56a (FIG. 1) and the second cam portion 42. Has an engaging portion 57 in which an engaging hole 57a is inserted, and a connecting portion 58.

  As shown in FIGS. 1 and 2, a guide plate 59 is provided above the upper blade 51 so as to cover the upper blade 51. The guide plate 59 has a through hole 59a having a diameter substantially equal to the diameter of the bolt 59A. The bolt 59A is inserted through the through hole 59a, the long hole 53a, and the long hole 56a, and is fixed by a nut 59B. The upper blade 51 and the lower blade 52 are guided by the bolt 59A so as to move only in the front-rear direction, and a movable range in the width direction is defined.

  With the above configuration, the eccentric cam 4 rotates and the first cam portion 41 and the second cam portion 42 rotate eccentrically, whereby the upper blade 51 and the lower blade 52 can be reciprocated along the front-rear direction. Since the phase difference between the first cam portion 41 and the second cam portion 42 is 180 degrees, the upper blade 51 and the lower blade 52 move in directions opposite to each other. That is, when the upper blade 51 moves forward, the lower blade 52 moves backward, and when the upper blade 51 moves backward, the lower blade 52 moves forward.

  Next, the operation of the trimming machine 1 will be described with reference to FIGS. In the initial state shown in FIG. 5A, when the operator holds the handle portion 23 and operates the throttle 23 </ b> A, the rotational force of the engine 31 is transmitted as the rotation of the output shaft 35. When the output shaft 35 rotates, the eccentric cam 4 rotates in the direction of the arrow as shown in FIGS. 5 (a) to 5 (g), the rotation angle of the eccentric cam 4 is 0 ° in FIG. 5 (a), 30 ° in FIG. 5 (b), 45 ° in FIG. 5 (c), and 90 ° in FIG. 5 (d). 5 (e) shows the positional relationship between the upper blade 51, the lower blade 52, and the eccentric cam 4 at 180 degrees, FIG. 5 (f) 210 degrees, and FIG. 5 (g) 270 degrees. The eccentric cam 4 rotates at a constant angular velocity. FIG. 6 shows the relationship between the rotation angle of the eccentric cam 4 and the distance between pitches. Here, the distance between pitches will be described. In the initial state shown in FIG. 5A (rotation angle is 0 degree), the cutting blade provided at the rearmost among the upper blades 51 is the first upper cutting blade 53A1, and the first of the upper blades 51 is the first. The second upper cutting edge 53A2 is the lower cutting edge provided on the same edge as the upper upper cutting edge 53A1, and the next cutting edge 53A of the first upper cutting edge 53A1 is currently overlapped with the second upper cutting edge 53A2. The 52 cutting blades 56A will be described as the lower cutting blade 56A1. Let P be the distance between the first upper cutting edge 53A1 and the second upper cutting edge 53A2. Hereinafter, the inter-pitch distance indicates the distance between the first upper cutting edge 53A1 and the lower cutting edge 56A1. For example, the distance between pitches is P in the state (initial position) where the rotation angle is 0 degree shown in FIG. 5A, and the first upper distance is shown in the state where the rotation angle is 180 degrees (first position) shown in FIG. Since the cutting edge 53A1 and the lower cutting edge 56A1 overlap, the distance between pitches becomes zero. In addition, although the relationship between the first upper cutting blade 53A1, the second upper cutting blade 53A2, and the lower cutting blade 56A1 has been described, adjacent cutting blades have the same relationship.

  When the eccentric cam 4 rotates, the first cam portion 41 and the second cam portion 42 rotate eccentrically with a phase difference of 180 degrees, and the upper blade 51 and the lower blade 52 are reciprocated in the front-rear direction. Until the eccentric cam 4 rotates 45 degrees from the initial position shown in FIG. 5 (a), the first cam portion 41 is engaged with the engaging portion 54 as shown in FIGS. 5 (b) and 5 (c). Rotate while engaging the portion defined by the curve C11. At this time, the first cam portion 41 slightly moves the engaging portion 54 of the upper blade 51 forward while contacting the vicinity of the proximity point 41B and the separation point 41A. Similarly, the second cam portion 42 The engaging portion 57 of the blade 52 is slightly biased to move backward. When the eccentric cam 4 further rotates and the rotation angle reaches 90 degrees, as shown in FIG. 5D, the first cam portion 41 is fitted into a portion of the engaging portion 54 that is defined by the curve C12. . When the eccentric cam 4 further rotates and the rotation angle reaches 180 degrees, as shown in FIG. 5E, the cutting blade 53A and the cutting blade 56A overlap to cut the branches and leaves between the cutting blades 53A and 56A. Pruning is performed. When the rotation angle is between 90 degrees and 180 degrees, the first cam portion 41 (second cam portion 42) biases the engaging portion 54 (engaging portion 57) of the upper blade 51 (lower blade 52). Thus, the rotation angle is largely moved forward (backward) as compared with the range of 0 to 90 degrees.

  Here, FIG. 6 shows the relationship between the rotation angle of the eccentric cam 4 and the pitch distance when the angular velocity of the eccentric cam 4 is constant. As shown in FIG. 6, the distance between pitches when the rotation angle of the eccentric cam 4 is 45 degrees is defined as a distance PL. In other words, from the state in which the cutting blade 53A and the cutting blade 56A overlap (the pitch distance is P and the rotation angle is 0 degree), the cutting blade 53A and the cutting blade 56A are relatively separated from each other by the distance L. The eccentric cam 4 rotates 45 degrees. Further, when the eccentric cam 4 rotates and the rotation angle becomes about 155 degrees, the distance between pitches becomes L. When the rotation angle is further rotated by about 25 degrees from the state where the rotation angle is about 155 degrees, and the rotation angle reaches 180 degrees, the cutting blades 53A and 56A move relative to each other by the distance L (distance between pitches is 0, rotation) The angle is 180 degrees). That is, the shapes of the eccentric cam 4 and the engaging portions 54 and 57 are such that the relative speeds of the upper blade 51 and the lower blade 52 are fast immediately before performing the trimming operation, and the upper blade 51 and The relative speed of the lower blade 52 is set to be slow.

  Further, the first cam portion 41 has a curve C21 in the engagement portion 54 until the eccentric cam 4 rotates 45 degrees from the state of the rotation angle of 180 degrees (first position) shown in FIG. Rotates while engaging the part defined by At this time, the first cam portion 41 slightly urges the engaging portion 54 of the upper blade 51 to move backward, and the second cam portion 42 slightly urges the engaging portion 57 of the lower blade 52. Move forward. When the eccentric cam 4 further rotates and the rotation angle reaches 210 degrees, as shown in FIG. 5 (f), the first cam portion 41 fits into a portion defined by the curve C 22 in the engaging portion 54. . When the eccentric cam 4 further rotates and the rotation angle reaches 360 degrees and returns to the initial position (second position), the cutting blades 53A and 56A are overlapped again as shown in FIG. 5A, and the cutting blades 53A and 56A are overlapped. A cutting operation is performed to cut branches and leaves between the two.

  As described above, since the curve C11 and the curve C21 correspond to each other, and the curve C12 and the curve 22 correspond to each other, the operation between the rotation angle of 180 degrees and 360 degrees is performed by the upper blade 51 and the lower blade 52. The operation is the same as the operation when the rotation angle is between 0 degrees and 180 degrees, except that the moving direction of is reverse. As shown in FIG. 6, the distance between the pitches when the rotation angle of the eccentric cam 4 is 225 degrees is the distance L. In other words, the eccentric cam 4 rotates 45 degrees until the cutting blades 53A and 56A overlap each other (the distance between the pitches is 0, the rotation angle is 180 degrees, and the first position) is relatively separated from the distance L. To do. When the eccentric cam 4 further rotates and the rotation angle becomes 335 degrees, the pitch distance becomes P−L. When the eccentric cam further rotates about 25 degrees from the state in which the distance P-L between the pitches is P-L (about 335 degrees), the cutting blade 53A and the cutting edge 56A move by the distance L, and the cutting blade 53A and the cutting edge 56A. (The distance between the pitches is P, the rotation angle is 360 degrees, and the second position). That is, the shape of the eccentric cam 4 and the engaging portion is such that the moving speed of the upper blade 51 and the lower blade 52 is fast immediately before the cutting operation, and the moving speed of the upper blade 51 and the lower blade 52 is slow immediately after the cutting operation. It is set to be. Thereafter, the above operation is repeated.

  The upper blade 51 and the lower blade 52 perform a reciprocating motion once to perform a trimming operation twice while the eccentric cam 4 rotates once. Specifically, when the rotation angle of the eccentric cam 4 is 180 degrees, 360 degrees (0 degrees), the cutting blades 53A and 56A overlap each other and perform a trimming operation. The shapes of the eccentric cam 4 and the engaging portions 54 and 57 are from the position (initial position) of the upper blade 51 and the lower blade 52 when the rotation angle is 0 degree to the position (first position) when 180 degrees. In both cases, the upper blade 51 and the lower blade 52 are relatively distant from each other in any case between the position at 180 degrees (first position) and the position at 360 degrees (second position). The rotational angle of the eccentric cam 4 necessary for moving by L is set so that the angle immediately before the cutting operation is larger than the initial state and immediately after the cutting operation.

  According to the trimming machine 1 of the present embodiment, the shape of the eccentric cam 4 and the engaging portions 54 and 57 is the rotation of the eccentric cam 4 that is necessary for the upper blade 51 and the lower blade 52 to move relative to each other by the distance L. Since the angle is set so that the angle immediately before the cutting operation is larger than the initial state and immediately after the cutting operation, the space between the cutting blade 53A and the cutting blade 56A that overlap in the initial state and immediately after the cutting operation is slowly widened. be able to. Therefore, more branches and leaves can be allowed to enter between the cutting blades 53A and 56A to prevent unreasonable cutting, and the work efficiency and convenience of the operator can be improved.

  Further, since the cutting blades 53A and 56A overlap twice while the eccentric cam 4 makes one rotation, the cutting operation can be performed twice while the upper blade 51 and the lower blade 52 each reciprocate once.

  Further, since the eccentric cam 4 engages with the engaging portion 54 and the engaging portion 57 to move the upper blade 51 and the lower blade 52 in opposite directions, either the upper blade 51 or the lower blade 52 is used. Compared with the case where only one of them is moved, when the cutting blades 53A and 56A overlap and separate from each other, the distance by which the upper blade 51 and the lower blade 52 are moved according to the rotation of the eccentric cam 4 is halved. Can be set.

  The trimming machine according to the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made within the scope described in the claims. For example, like the trimming machine 101 shown in FIG. 7, the upper blade 151 and the lower blade 152 are biased by the springs 155B and 158B, thereby maintaining the engagement between the eccentric cam 104 and the engaging portions 154 and 157. It may be a configuration. In addition to the configuration of the main housing 22, the main housing 122 includes a pair of fixing portions 122 </ b> C that are provided at a predetermined distance in the width direction of the upper blade 151 and the lower blade 152. The eccentric cam 104 has a first cam portion 141 and a second cam portion 142, and is provided so as to be rotatable about the rotation shaft 22B. The first cam portion 141 and the second cam portion 142 have the same shape and are set to a phase difference of 180 degrees. The upper blade 151 has a blade portion 53, an engagement portion 154, and a connection portion 155. Similarly, the lower blade 152 includes a blade portion 56, an engagement portion 157, and a connection portion 158. The upper blade 151 is the same as the upper blade 51 except that it has an engaging portion 154 instead of the engaging portion 54. The lower blade 152 is the same as the lower blade 52 except that it has an engaging portion 157 instead of the engaging portion 57. The engaging portions 154 and 157 are formed with a substantially D-shaped engaging hole 154a and a substantially inverted D-shaped through hole 157a, respectively. A first cam portion 141 and a second cam portion 142 are disposed in the engagement holes 154a and 157a, respectively. The connecting portions 155 and 158 are provided with fixing pieces 155A and 158A for fixing one ends of the springs 155B and 158B, respectively. The other ends of the springs 155B and 158B are fixed to the fixing portion 122C. The spring 155B biases the upper blade 151 rearward with respect to the fixed portion 122C so that the engaging portion 154 always engages with the first cam portion 141. The spring 158B urges the lower blade 152 forward relative to the fixed portion 122C so that the engaging portion 157 always engages with the second cam portion 142. According to such a configuration, the relationship between the rotation angle of the eccentric cam 104 and the pitch distance between the upper blade 151 and the lower blade 152 as shown in FIG. be able to. However, in the above-described embodiment, the eccentric cam 4 and the upper blade 51 are shaped so that the first cam portion 41 and the engaging portion 54 are always in contact with each other at least at two points. There is no need to provide means, and more effects can be obtained in terms of the number of parts and the assemblability. In addition, the eccentric cam 104 shown in FIG. 7 includes the engagement portions 154 and 157 between the state where the upper blade 151 and the lower blade 152 overlap and the state where the upper blade 151 and the lower blade 152 are separated by a predetermined distance. Of these, the contacting portion comes into contact with the engaging portions 154 and 157 from the state in which the upper blade 151 and the lower blade 152 are separated to the state in which the upper blade 151 and the lower blade 152 overlap each other after moving by a predetermined distance. It may be formed by a gentler curve than the portion.

  In the above-described embodiment, both the upper blade 51 and the lower blade 52 are engaged with the eccentric cam 4 and reciprocated in the front-rear direction, but either one may reciprocate. For example, the shape of the eccentric cam and the engaging portion is set so that the lower blade 52 is fixed to the main housing 22 so as not to move, and the upper blade moves a distance P when the eccentric cam rotates 180 degrees from the initial position. May be. Further, the trimming machine has been described as a so-called hedge trimmer in which the upper blade and the lower blade are slid together by being driven back and forth in the front-rear direction, but the upper portion having a plurality of saw-shaped blades on the substantially fan-shaped circumferential portion. It may be in the form of a gardening hair clipper in which the blade and the lower blade are reciprocated in the left-right direction and cut by sliding.

  The curve C11 defines the surface of the engaging portion 54 that the contact point 41A contacts when the rotation angle of the eccentric cam 4 is 0 degree to 45 degrees, but the surface defined by the curve C11 is The rotation angle is not limited to 45 degrees, and the rotation angle may be set to be in contact with the contact point 41A between 0 degree and a predetermined angle. For example, when the predetermined angle is 30 degrees, the curve C12 may be set so that the contact point 41A and the engaging portion 54 are in contact with each other when the rotation angle is between 150 degrees and 180 degrees. Further, instead of the engine 31, an electric motor may be used as a drive source. In this case, for example, the operation of the present embodiment may be realized by controlling the speed of the cutting blade by a microcomputer or the like.

DESCRIPTION OF SYMBOLS 1,101 ... Trimming machine, 2 ... Housing, 3 ... Motor | power_engine part, 4,104 ... Eccentric cam, 4a ... Through-hole, 4A ... Gear part, 5 ... Trimming Blade, 21 ... casing, 22, 122 ... main housing, 22A ... bearing, 22B ... rotating shaft, 23 ... handle part, 23A ... throttle, 24 ... protective cover, 24A ... auxiliary handle, 31 ... engine, 31A ... cylinder, 31B ... piston, 31C ... connecting rod, 31D ... crank, 31E ... crankcase, 31F ... crankshaft 32 ... Flywheel, 32A ... Magneto, 33 ... Centrifugal clutch, 34 ... Coil, 35 ... Output shaft, 35A ... Gear part, 36 ... Fuel tank, 41, 141. First cam portion, 41A ... contact point, 41B ... proximity point, 42, 142 ... second cam portion, 51, 151 ... upper blade, 52, 152 ... lower blade, 53 , 56 ... Blade part, 53A, 56A ... Cutting blade, 53A1 ... Upper cutting blade, 53A2 ... Upper cutting blade, 53a, 56a ... Long hole, 54, 57, 154, 157 .. Engaging portion, 54a, 57a, 154a, 157a ... engaging hole, 55, 58, 155, 158 ... connecting portion, 56A1 ... lower cutting edge, 59 ... guide plate, 59A ... -Bolt, 59a ... through hole, 59B ... nut, 155A, 158A ... fixed piece, 155B, 158B ... spring, AX ... axis, C1, C11, C12, C2, C21, C22 ···curve

Claims (11)

A driving source;
An output shaft for outputting power from the drive source;
An eccentric cam that rotates in response to the output of the output shaft and converts the rotational motion transmitted from the output shaft into a reciprocating motion;
A first trimming blade having a plurality of first cutting edges;
A second cutting blade that has a plurality of second cutting blades and cuts an object together with the first cutting blade when the first cutting blade and the second cutting blade are close to each other; With
At least one of the first cutting blade and the second cutting blade is provided with an engaging portion that engages with the eccentric cam, and the engaging portion engages with the eccentric cam, thereby The first cutting blade and the second cutting blade relatively reciprocate,
The eccentric cam has a first interval between a state where the first cutting edge and the second cutting edge are overlapped and a state where the first cutting edge and the second cutting edge are separated from each other by a predetermined distance. Rotate the angle,
The eccentric cam moves from the state where the first cutting edge and the second cutting edge are separated from each other by a predetermined distance until the first cutting edge and the second cutting edge overlap each other. Rotate 2 degrees,
The shape of the eccentric cam and the engaging portion is set so that the first angle is larger than the second angle. The first cutting blade and the second cutting blade perform one reciprocating movement while the eccentric cam makes one rotation,
The first cutting blade and the second cutting blade are disposed at an initial position when the eccentric cam is rotated by 0 degrees, and are disposed at a first position when the eccentric cam is rotated by 180 degrees, The eccentric cam is arranged at a second position in a state where the eccentric cam is rotated 360 degrees, and the first cutting edge and the second cutting edge overlap each other at the initial position, the first position, and the second position. ,
The shapes of the eccentric cam and the engagement portion are the second shape in any case between the initial position and the first position and between the first position and the second position. The trimming machine according to claim 1, wherein the first angle is set to be larger than the first angle. The engaging portion has a first engaging portion provided on the first cutting blade, and a second engaging portion provided on the second cutting blade,
The eccentric cam engages with the first engagement portion and the second engagement portion, respectively, and moves the first cutting blade and the second cutting blade in directions opposite to each other. The trimming machine according to claim 1 or 2, wherein the trimming machine is characterized. The eccentric cam has a contact point that is farthest from the center of rotation of the outer periphery of the eccentric cam,
The engaging portion is formed between the state where the first cutting edge and the second cutting edge overlap and the state where the first cutting edge and the second cutting edge are separated by a predetermined distance. A portion that contacts the contact point moves a predetermined distance from a state where the first cutting edge and the second cutting edge are separated from each other, and the first cutting edge and the second cutting edge overlap each other. The trimming machine according to any one of claims 1 to 3, wherein the trimming machine is formed by a curve that is gentler than a portion that is in contact with the contact point until the state.   The engaging portion is configured such that the first cutting edge and the second cutting edge are separated from each other by a predetermined distance from a state in which the first cutting edge and the second cutting edge of the engaging portion overlap each other. 5. The trimming machine according to claim 4, wherein a portion that contacts the contact point until the state is formed so as to substantially follow a trajectory through which the contact point passes when the eccentric cam rotates.   The engaging portion moves from the state where the first cutting edge and the second cutting edge are separated from each other to a state where the first cutting edge and the second cutting edge overlap each other. 6. The trimming machine according to claim 5, wherein a portion in contact with the contact point is provided closer to the rotation center of the eccentric cam than the locus.   The engaging portion has a shape that fits to the outer periphery of the eccentric cam in a state in which the first cutting blade and the second cutting blade are rotated 90 degrees from a state in which the first cutting blade and the second cutting blade are overlapped. The trimming machine according to any one of claims 1 to 6.   The engaging portion has an axis extending through the center of rotation of the eccentric cam and extending parallel to the direction of the reciprocating motion, and is defined by a curve that is substantially point-symmetric with respect to an arbitrary point on the axis. A trimming machine according to any one of claims 1 to 7.   2. An urging means for urging either one of the engaging portion and the eccentric cam toward the other and maintaining the engagement of the engaging portion and the eccentric cam. The trimming machine according to claim 8.   The eccentric cam is engaged between the state where the first cutting edge and the second cutting edge overlap and the state where the first cutting edge and the second cutting edge are separated from each other by a predetermined distance. The portion that contacts the joint moves the predetermined distance from the state where the first cutting edge and the second cutting edge are separated from each other, and the first cutting edge and the second cutting edge overlap each other. The trimming machine according to claim 9, wherein the trimming machine is formed by a curve that is gentler than a portion that comes into contact with the engaging portion until the state. A driving source;
An output shaft for outputting power from the drive source;
An eccentric cam that rotates in response to the output of the output shaft and converts the rotational motion transmitted from the output shaft into a reciprocating motion;
A first trimming blade having a plurality of first cutting edges;
A second cutting blade that has a plurality of second cutting blades and cuts an object together with the first cutting blade when the first cutting blade and the second cutting blade are close to each other; With
A trimming machine characterized in that a relative speed when the first trimming blade and the second trimming blade are separated from each other is slower than a relative speed when approaching.

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