JP6440422B2 - Cordless brush cutter head - Google Patents

Description

  The present invention relates to a cord type brush cutter for a brush cutter that can automatically feed a cord when the cord becomes shorter during operation.

  Conventionally, those described in Patent Documents 1 and 2 are known as a cord type brush cutter for a brush cutter capable of automatically feeding out a cord when the cord becomes shorter during operation. In the cord type brush cutter head of Patent Literature 1, the engagement between the stopper and the protrusion is released by the centrifugal force applied to the cord and the change in the rotational speed, the ring rotates, and the cord is fed out. According to this cord type brush cutter brush cutter head, the cord is shortened by a certain length during work, the load on the cord is reduced, the cord tension is also reduced, the engine speed is increased, and the stopper is swung. The centrifugal force at the moving end increases and moves outward against the pressing force of the spring, the engagement between the rocking end of the stopper and the protrusion is released, the ring rotates and the cord starts to be fed out. Then, the centrifugal force applied to the cord returns to the original magnitude, the swinging end of the stopper is returned and the swinging end of the stopper is engaged with the adjacent protrusion, and the rotation of the ring is stopped, and the constant length The chord feed stops.

  Further, the cord type brush cutter head of Patent Document 2 is a device in which the ball pushes the cord reel upward by a change in centrifugal force applied to the ball, the cord reel and the case are unlocked, and the cord is fed out. is there. According to this cord type brush cutter brush cutter head, the cord is shortened by a certain length during work, the load on the cord is reduced and the number of rotations of the brush cutter is increased, so the centrifugal force applied to the ball is increased. The ball moves upward and the cord reel is pushed upward against the pressing force of the spring. Thus, after the cord reel is rotated by a predetermined angle and a cord having a certain length is fed out, the feeding of the cord is stopped. When the number of rotations of the brush cutter decreases, the centrifugal force applied to the ball decreases, the ball moves inward and downward, and the cord reel is pushed downward.

JP-A-6-335212 JP 7-274656 A

  However, in the cord type brush cutter head of Patent Document 1 described above, if the cord is extremely shortened at a time during work, the load on the cord is extremely reduced and the rotational speed is extremely increased. The oscillating end continues to move outward against the pressing force of the spring, the ring continues to rotate, the engagement with one or more adjacent protrusions is released, and the cord continues to be fed out. Then, when the length of the cord is increased, the centrifugal force returns to the original magnitude, the swinging end of the stopper is returned, and the swinging end of the stopper and the protrusion are engaged. As a result, the rotation of the ring is stopped, and the feeding of the cord having a predetermined length is stopped. At this time, since the ring rotates rapidly, when the rocking end of the stopper is engaged with the protrusion, a strong impact is applied to the protrusion and the protrusion is damaged. Further, in this cord type brush cutter brush cutter head, the amount of cord feeding is affected by variations in springs and aging deterioration.

  Further, in the cord type brush cutter head of Patent Document 2 described above, if the cord becomes extremely short at a time during work, the load on the cord is extremely reduced and the rotational speed is extremely increased. The applied centrifugal force is also large, and the ball stays on the outside and the cord reel is pushed upward. With this cord type brush cutter, the cord type brush cutter is manually operated because the next fixed length of cord cannot be paid out unless the ball moves inward and the cord reel is pushed downward. It is necessary to reduce the rotational speed of the brush cutter head. Also in this cord type brush cutter brush cutter head, the amount of cord feeding is affected by variations in the spring and aging degradation.

  The present invention has been made in view of such a conventional problem, and even when the length of the cord is extremely shortened at a time during work, the length becomes a predetermined length without damaging the parts. It is intended to provide a cord type brush cutter for a brush cutter that can automatically feed a cord up to a maximum.

In order to solve the above-described problem, the characteristics of the cord type brush cutter brush cutter according to claim 1 are:
The both ends of the cord wound around the cord holder and housed in the case protrude from the case,
About the axis of the mounting shaft of Kari払head both ends of the cord is rotated at a high speed in coding trimmer for Kari払head mow grass, a lid that rotates the axis around together with the cord holder a, the case is rotatably disposed in the axial center around between the cord holder and lid, while the of the lid or the case, the stopper having a locking claw at the tip rotation An outer peripheral surface having a plurality of locking surfaces for rotating the case integrally with the cord holder and the lid by locking with the locking claw and being circularly supported on the other side of the lid or the case. A guide portion that guides a return portion provided at a rear end portion of the stopper and moves the locking claw along the outer peripheral surface is provided on the other side of the lid or the case. It is provided inside the outer peripheral surface.

  The cord type brush cutter head according to claim 2, wherein the return portion of the stopper is a protrusion projecting to the other side of the lid or the case, and the guide portion of the stopper is That is, it is a ridge or a ridge that is guided by sliding the protrusion.

  The cord type brush cutter head according to claim 3 is characterized in that a spring for pressing the locking claw in the direction of the outer peripheral surface is provided on the one of the lid or the case.

  The cord type brush cutter head according to claim 4 is characterized in that the cord holder includes a cylindrical cylindrical portion around which the cord is wound, and two outer circumferential portions of the cylindrical portion are arranged at symmetrical positions in the radial direction. A through hole is provided, and two cord insertion holes are provided at radially outer positions on the outer periphery of the case. When the cord is wound around the cord holder, the two through holes and two By inserting the cord through the cord insertion hole and rotating the case and the cord holder relative to each other, the cord can be wound around the cylindrical portion of the cord holder. The two through holes and the two cord insertion holes are arranged in a straight line at any engagement position with the stop surface.

  In the cord type brush cutter head according to claim 1, when the rotation of the cord holder is smaller than the predetermined rotation, the latching claw and the latching surface are engaged to rotate the case integrally with the cord holder and the lid. Let When the rotation of the cord holder reaches a predetermined value or more, the centrifugal force applied to the stopper increases, so that the engagement between the locking claw and the locking surface is released, and the case, the code holder, and the lid rotate relative to each other. . At this time, the locking claw is moved along the outer peripheral surface to the engagement position with the next locking surface by the return portion and the guide portion, and a cord having a certain length is fed out. While the rotation of the cord holder is greater than or equal to the predetermined rotation, this operation occurs continuously, and the movement of the locking claw to the engagement position with the adjacent locking surface is not skipped. And does not rotate rapidly with respect to the lid. Therefore, even if the locking claw and the locking surface are engaged, a strong impact force is not applied to the stopper, and damage to the stopper and the locking surface can be suppressed. In addition, since the cord continues to be fed out until the rotation of the cord holder becomes smaller than the predetermined rotation and the locking claw and the locking surface engage with each other, the cord protruding from the case without the accelerator operation has a predetermined length. Is secured.

  Further, in this cord type brush cutter brush cutter head, since the engaging claw and the engaging surface are engaged and released by the centrifugal force applied to the stopper, the feeding amount of the cord is stable. In other words, when the spring pressing force is used, the amount of feeding the cord depends on the spring variation and aging deterioration, but the centrifugal force applied to the stopper is determined by the shape of the stopper, etc. There is little influence on the feeding amount of the code. Therefore, according to this cord type brush cutter brush cutter head, even if the length of the cord becomes extremely short at the same time during work, the cord type brush cutter is automatically operated until it reaches a predetermined length without damaging the parts. You can pay out the code.

  In the bush cutter for a cord type brush cutter according to claim 2, the guiding part that is a ridge or a concave slid is guided by sliding the write-back part that is a protrusion, so that the locking claw is arranged along the outer peripheral surface. It can be reliably moved to the locking surface.

  In the cord type brush cutter head according to claim 3, since the spring presses the stopper claw of the stopper toward the outer peripheral surface, the cord type brush cutter can wind the cord around the cord holder without being disassembled. In the case of the brush head, the cord can be easily wound around the cord holder. In this cord type brush cutter brush cutter head, the engaging claw and the engaging surface are engaged and released by the centrifugal force applied to the stopper. It is small enough to press in the surface direction. For this reason, the influence of the spring on the feeding amount of the cord is extremely small.

  According to a fourth aspect of the present invention, there is provided a cord-type brush cutter brush head having two through-holes at a radially symmetrical position on the outer periphery of the cylindrical portion of the cord holder, and two radial holes on the outer periphery of the case. Two cord insertion holes are provided. And in either engagement position of the latching claw of a stopper and the latching surface of a case, two through-holes and two cord insertion holes are arrange | positioned on a straight line. Therefore, when winding the cord around the cord holder, the two through holes and the two cord insertion holes can be easily arranged in a straight line, and both ends of the cord can be easily passed through the insertion holes.

The attachment diagram to the brush cutter of the cord type brush cutter head of the embodiment. FIG. 3 is an exploded perspective view of a cord type brush cutter head according to the embodiment. The front view and sectional drawing of a stopper which concern on the brush-type brush cutter head of embodiment. The front view of a case in connection with the brush cutter head for the cord type brush cutter according to the embodiment. The top view of a case in connection with the brush cutter head for the cord type brush cutter according to the embodiment. The bottom view of a case in connection with the brush-type brush cutter head of an embodiment. Sectional drawing of a cord holder in connection with the bush cutter head for cord type brush cutters of an embodiment. The figure which concerns on the brush-type brush cutter head of embodiment and the stopper was assembled | attached to the case. The figure which shows the relationship between a case and a stopper when it concerns on the brush-type brush cutter head of embodiment, and rotation of a cord holder becomes more than predetermined rotation. FIG. 4 is an enlarged view of a case and a stopper according to the cord type brush cutter head of the embodiment. The figure which shows the relationship between a case and a stopper when it concerns on the brush-type brush cutter head of embodiment, and rotation of a cord holder becomes more than predetermined rotation. The figure which shows the relationship between the case and the stopper when the rotation of the cord holder becomes smaller than a predetermined rotation in connection with the cord type brush cutter head of the embodiment. The partially enlarged view which shows the relationship between a case, a stopper, and a cord when the length of the cord is extremely shortened at once in the cord type brush cutter head of the embodiment. The partially enlarged view which shows the relationship between a case, a stopper, and a cord when the length of the cord is extremely shortened at once in the cord type brush cutter head of the embodiment. The partially enlarged view which shows the relationship between a case, a stopper, and a cord when the length of the cord is extremely shortened at once in the cord type brush cutter head of the embodiment. The partially enlarged view which shows the relationship between a case, a stopper, and a cord when the length of the cord is extremely shortened at once in the cord type brush cutter head of the embodiment. The figure which concerns on the brush-type brush cutter head of embodiment, and shows the winding of the cord to the cord holder.

  An embodiment embodying a cord type brush cutter head according to the present invention will be described below with reference to the drawings. FIG. 1 is a view showing the attachment of the cord type brush cutter brush head 1 to the operation rod 90 of the brush cutter. As shown in FIG. 1, the cord type brush cutter brush head 1 is attached to a mounting shaft 91 at a tip end portion of an operation rod 90 of the brush cutter by a bolt 92. A cord C projects from the cord-type brush cutter brush cutter head 1.

  FIG. 2 is an exploded perspective view of the cord type brush cutter brush cutter head 1 according to the embodiment. As shown in FIG. 2, the cord-type brush cutter brush head 1 includes a lid 2, a stopper 10, a spring 15, a case 20, and a cord holder 30. The cord-type brush cutter brush cutter head 1 can mow the grass by rotating both ends of the cord C around the axis L of the attachment shaft 91 at a high speed. The lid 2 includes a hollow disc-shaped lid main body 3 and a cylindrical cylindrical portion 4 protruding from the center of the lid main body 3. A female screw 4a is formed on the inner periphery of the cylindrical portion 4, and the female screw 4a is screwed with a male screw 31b formed on the outer peripheral portion of a cylindrical portion 31 of the cord holder 30 described later. Then, the lid 2 and the cord holder 30 are integrally rotated by screwing the female screw 4a and the male screw 31b to fix the lid 2 and the cord holder 30 together. In addition, two columnar rotating columns 5, two columnar pressing columns 6, and two attachment portions 7 are provided at symmetrical positions on the concentric circles.

  As shown in FIG. 3, the stopper 10 has a plate shape slightly bent in a bowl shape, and is a central portion between the front end portion 10 a and the rear end portion 10 b, and a rotation hole at a position near the front end portion 10 a. 11 is opened. The rotating column 5 of the lid 2 is inserted into the rotating hole 11 so that the stopper 10 can be rotated around the rotating column 5. Further, a locking claw 12 is formed at the distal end portion 10a. Further, the weight from the rotation hole 11 to the rear end portion 10b is heavier than the weight from the rotation hole 11 to the front end portion 10a. A step 14 is formed at the tip 10a. Further, a cylindrical projection 13 as a return portion is provided in the rear end portion 10b so as to protrude in the direction of the case 20. 3A is a front view of the stopper 10, and FIG. 3B is a cross-sectional view taken along the line III-III in FIG.

  The spring 15 is a torsion spring, and includes a coil portion 15a, a first arm 15b, and a second arm 15c. The pressing support 6 of the lid 2 is inserted into the coil portion 15 a and the first arm 15 b is hung on the mounting portion 7 of the lid 2. Then, the second arm 15 c is hung on the step portion 14 of the stopper 10. As a result, the tip 15 a of the stopper 10 is pressed outward in the radial direction of the lid 2 by the spring 15.

  As shown in FIGS. 4 to 6, the case 20 has a cylindrical shape having recesses 21 and 22 on both surfaces, and an insertion hole 20 a is formed in the center. The concave portion 21 accommodates the stopper 10, and an outer peripheral surface 23 for guiding the locking claw 12 of the stopper 10 is formed in a circular shape on the outer periphery, and the locking claw 12 of the stopper 10 is provided at eight locations on the outer peripheral surface 23. A locking surface 24 for locking is formed. Further, on the inner side of the outer peripheral surface 23, a protrusion 25 is provided as a guide portion that guides the protrusion 13 provided on the rear end portion 10 b of the stopper 10 and moves the locking claw 12 along the outer peripheral surface 23. It has been. The protrusion 13 is slid on the side surface on the axis L side of the ridge 25 to forcibly move the locking claw 12 along the outer peripheral surface 23. Two sets of cord insertion holes 28 are provided at symmetrical positions on the outer peripheral portion on the concave portion 22 side. In the present embodiment, the ridge 25 is employed as the guiding portion. However, instead of the ridge 25, a recess is employed so that the projection 13 slides in the recess of the recess. Good.

  As shown also in FIG. 7, the cord holder 30 has a cylindrical portion 31, a bottom plate 32, and a flange 33. The cylindrical portion 31 has a cylindrical shape and is erected at the center of a hollow disc-shaped bottom plate 32. A disc-shaped flange 33 is provided at the center of the cylindrical portion 31, and a cord winding portion 34 is formed between the bottom plate 32 and the flange 33. The cord C is wound around the cord winding portion 34 and stored. Two through-holes 35 are formed at symmetrical positions of the cylindrical portion 31 located in the winding portion 34. Further, a male screw 31 b is formed on the outer peripheral portion of the cylindrical portion 31 on the distal end side of the cord winding portion 34. Further, a central hole 31a is formed in the inner peripheral surface of the cylindrical portion 31, and the cord C can be inserted into the cord winding portion 34 from the central hole 31a through the through hole 35 when the cord C is wound. It has become.

  The assembling method of the cord type brush cutter brush cutter head 1 will be described below. As shown in FIG. 2, first, the rotating column 5 of the lid 2 is inserted into the rotating hole 11 of the stopper 10. Then, the pressing support 6 of the lid 2 is inserted into the coil portion 15 a of the spring 15, the first arm 15 b is hung on the mounting portion 7 of the lid 2, and the second arm 15 c is hung on the stepped portion 14 of the stopper 10. In this way, the stopper 10 is attached to the lid 2, and the distal end portion 10 a of the stopper 10 is pressed outward in the radial direction of the lid 2 by the spring 15.

  Thereafter, the cylindrical portion 4 of the lid 2 is inserted into the insertion hole 20a of the case 20, and the male screw 31b of the cord holder 30 and the female screw 4a of the lid 2 are screwed together to fix the lid 2 and the cord holder 30 together. Thus, the cord type brush cutter brush cutter head 1 is assembled.

Next, the operation of the cord type brush cutter brush cutter head 1 will be described. However, it is assumed that the cord C is wound around the cord holder 30 and stored in the case 20, and both ends of the cord C are projected from the cord insertion hole 28 of the case 20 by a predetermined length. When the drive source of the cord type brush cutter is driven, the locking claw 12 of the stopper 10 is engaged with the locking surface 24 of the case 20 as shown in FIG.
The lid 2, the cord holder 30, and the case 20 are integrated as a shaft.
It rotates counterclockwise around the center L. As a result, the cord C can rotate at high speed to mow the grass. However, FIG. 8 is the figure which looked at the case 20 from the lid | cover 2 direction, and the description of the lid | cover main body 3 and the cylindrical part 4 is abbreviate | omitted.

  Next, a case where the code C is shortened by a certain length during the operation will be described. When the cord C is shortened by a certain length, the load applied to the cord C is reduced, the rotational speed of the cord-type brush cutter brush head 1 is increased, and the centrifugal force applied to the stopper 10 is increased. Here, since the weight from the rotation hole 11 to the rear end portion 10b of the stopper 10 is heavier than the weight from the rotation hole 11 to the front end portion 10a, the number of rotations of the cord type brush cutter brush cutter head 1 is increased. Becomes greater than or equal to a predetermined rotational speed, the difference between the centrifugal force applied to the rear end portion 10b and the centrifugal force applied to the front end portion 10a increases. As a result, as indicated by the arrow in FIG. 9, the stopper 10 rotates counterclockwise and the engagement between the locking claw 12 and the locking surface 24 is released. In addition, description of the spring 15 is abbreviate | omitted in FIGS.

  Here, as shown in FIG. 10, among the contact positions between the locking claw 12 and the locking surface 24 from the rotation center of the stopper 10, the longest distance is a distance D1, and the shortest distance is a distance D2. The distance D1 from the engagement state of the locking claw 12 and the locking surface 24 (FIG. 8) to the state where the engagement of the locking claw 12 and the locking surface 24 is completely released (FIG. 9). As shown in FIG. 9, the case 20 rotates slightly counterclockwise as indicated by an arrow with respect to the cord holder 30 and the lid 2 by the amount of the difference from the distance D2. As described above, since the engagement between the locking claw 12 and the locking surface 24 (FIG. 8) is completely disengaged from the engagement claw 12 and the locking surface 24 (FIG. 9). Since the locking claw 12 needs to push back the case 20, the engagement state (FIG. 8) between the locking claw 12 and the locking surface 24 can be stabilized without using an elastic body such as a spring. Can be maintained. Note that the pressing force of the spring 15 used in the present embodiment is the minimum necessary for the front end portion 10a of the stopper 10 to press outward in the radial direction of the lid 2, so that the spring 15 extends the cord C. The effect on quantity is very small.

  When the engagement between the locking claw 12 and the locking surface 24 is completely released, the case 20 rotates in the clockwise direction indicated by the arrow with respect to the cord holder 30 and the lid 2 as shown in FIG. At this time, the protrusion 13 is slid on the side surface of the ridge 25 on the axis L side, and the locking claw 12 is forcibly moved along the outer peripheral surface 23. For this reason, as shown in FIG. 12, the locking claw 12 reliably engages with the adjacent locking surface 24. Thus, a cord C having a certain length corresponding to the rotation of the case 20 relative to the cord holder 30 and the lid 2 is extended from the case 20 through the cord insertion hole 28.

  Next, the case where the length of the code C becomes extremely short at once will be described. However, when the rotation speed of the cord holder 30 is R (rpm) and the rotation speed R (rpm) is equal to or higher than the predetermined rotation speed R0 (rpm), the engagement between the locking claw 12 and the locking surface 24 is disengaged. . FIG. 13 shows a state in which the code C has become extremely short at once. The code at this time is represented by C (0), and the locking surface engaged with the locking claw 12 at this time is represented by 24 (0). In this case, when R (rpm)> R0 (rpm) is satisfied and the code C is shortened by a certain length, the engagement between the locking claw 12 and the locking surface 24 (0) is caused by the reason already described. The case 20 is released, and the case 20 rotates in the clockwise direction indicated by the arrow with respect to the cord holder 30 and the lid 2. At that time, the protrusion 13 is slid on the side surface of the ridge 25 on the axis L side, and the locking claw 12 is forcibly moved along the outer peripheral surface 23.

  Then, as shown in FIG. 14, after the case 20 is rotated by 45 degrees with respect to the cord holder 30 and the lid 2, the locking claw 12 is securely engaged with the adjacent locking surface 24 (1), and the case A cord C having a certain length is extended from 20 through the cord insertion hole 28. The code at this time is represented by code C (1).

  Even in the state of FIG. 14, since the cord C (1) does not reach the predetermined length, the load applied to the cord C (1) does not increase, and the rotation speed R (rpm) of the cord holder 30 does not sufficiently decrease. Therefore, in the case where R (rpm)> R0 (rpm) still remains and the code C is shortened by a certain length, the locking claw 12 and the locking surface 24 (1) Is released, and the case 20 rotates in the clockwise direction indicated by the arrow with respect to the cord holder 30 and the lid 2. At that time, the protrusion 13 is slid on the side surface of the ridge 25 on the axis L side, and the locking claw 12 is forcibly moved along the outer peripheral surface 23.

  Then, as shown in FIG. 15, after the case 20 is further rotated by 45 degrees with respect to the cord holder 30 and the lid 2, the locking claw 12 is reliably engaged with the adjacent locking surface 24 (2), A cord C having a predetermined length is extended from the case 20 through the cord insertion hole 28. The code at this time is represented by code C (2).

  Even in the state of FIG. 15, since the cord C (2) does not reach the predetermined length, the load applied to the cord C (2) does not increase, and the rotation speed R (rpm) of the cord holder 30 does not sufficiently decrease. Therefore, in the case where R (rpm)> R0 (rpm) still remains and the code C is shortened by a certain length, the locking claw 12 and the locking surface 24 (2) Is released, and the case 20 rotates in the clockwise direction indicated by the arrow with respect to the cord holder 30 and the lid 2. At that time, the protrusion 13 is slid on the side surface of the ridge 25 on the axis L side, and the locking claw 12 is forcibly moved along the outer peripheral surface 23.

  Then, as shown in FIG. 16, after the case 20 is further rotated by 45 degrees with respect to the cord holder 30 and the lid 2, the locking claw 12 is securely engaged with the adjacent locking surface 24 (3), A cord C having a predetermined length is extended from the case 20 through the cord insertion hole 28. The code at this time is represented by code C (3). Since the cord C (3) has reached a predetermined length, the load applied to the cord C (3) is increased, and the rotation speed R (rpm) of the cord holder 30 is sufficiently reduced. Therefore, R (rpm) <R0 (rpm) is satisfied, and the locking claw 12 is stabilized in a state of being engaged with the locking surface 24 (3), and the relative rotation of the case 20 with respect to the cord holder 30 and the lid 2 is stopped. At the same time, the feeding out of the code C is also stopped.

  As described above, as long as the rotation speed R (rpm) of the cord holder 30 is larger than the predetermined rotation speed R0 (rpm), even if the locking claw 12 is reliably engaged with the adjacent locking surface 24, the stopper 10 The engagement between the locking claw 12 and the adjacent locking surface 24 is immediately released by the applied centrifugal force. Then, this operation is repeated one after another until the rotational speed R (rpm) of the cord holder 30 becomes smaller than the predetermined rotational speed R0 (rpm). Finally, the cord C protruding from the case 20 through the cord insertion hole 28 is It becomes a predetermined length.

Next, winding of the cord C around the cord holder 30 will be described with reference to FIG.
However, FIG. 17 is a view of the case 20 as viewed from the cord holder 30 side.
It is the figure cut | disconnected by the surface perpendicular | vertical to the axial center L in 4 parts. First, the case 20 is rotated in the direction indicated by the arrow with respect to the cord holder 30 so that the cord insertion hole 28 of the case 20 and the through hole 35 of the cord holder 30 are arranged in a straight line. In this operation, when the case 20 is viewed from the direction of the lid 2, the case 20 is rotated counterclockwise with respect to the cord holder 30, as shown in FIG. At this time, the tip 15a of the stopper 10 is moved by the spring 15.
Is slightly pressed outward in the radial direction of the lid 2, so that the rotational resistance gradually increases before the locking claw 12 and the locking surface 24 are engaged. Then, when the locking claw 12 and the locking surface 24 are engaged with each other, the rotational resistance is reduced at a stroke, so that the engagement position between the locking claw 12 and the locking surface 24 can be easily grasped. Note that the case 20 cannot be rotated clockwise relative to the cord holder 30 against the engagement between the locking claw 12 and the locking surface 24.

  Since the two through holes 35 and the two cord insertion holes 28 are arranged in a straight line at any of the engagement positions of the locking claw 12 of the stopper 10 and the locking surface 24 of the case 20, By engaging the locking claw 12 and the locking surface 24 in this way, the two through holes and the two cord insertion holes can be easily arranged on a straight line. When eight locking surfaces 24 are provided on the outer peripheral surface 23 as in this cord type brush cutter, the case 20 is moved relative to the maximum of three locking surfaces 24 (135 degrees). What is necessary is just to rotate.

  Thereafter, as shown in FIG. 17, one end of the cord C is inserted into the central hole 31 b of the cord holder 30, and is sequentially drawn through the through hole 35 and the cord insertion hole 28 and pulled out of the case 20. Similarly, the other end of the cord C is arranged so that the central portion of the cord C is disposed in the central hole 31b. Thus, the cord C is attached to the cord holder 30. When the case 20 is rotated with respect to the cord holder 30 in the direction indicated by the arrow, the cord C is wound around the cord holder 30.

  In the cord type brush cutter head of the embodiment, when the rotation of the cord holder 30 is smaller than the predetermined rotation, the locking claw 12 and the locking surface 24 are engaged, and the case 20 is connected to the cord holder 30 and the lid. 2 and rotate together. When the rotation of the cord holder 30 reaches a predetermined value or more, the centrifugal force applied to the stopper 10 is increased, so that the engagement between the locking claw 12 and the locking surface 24 is released, and the case 20 and the cord holder 30 and The lid 2 rotates relatively. At this time, the locking claw 12 is moved along the outer peripheral surface 23 to the engagement position with the next locking surface 24 by the projection 13 and the protrusion 25, and the cord C having a certain length is fed out. As long as the rotation of the cord holder 30 is greater than or equal to the predetermined rotation, this operation occurs continuously, and the movement of the locking claw 12 to the engagement position with the adjacent locking surface 24 is not skipped. 20 does not rotate rapidly with respect to the cord holder 30 and the lid 2. Therefore, even if the locking claw 12 and the locking surface 24 are engaged, a strong impact force is not applied to the stopper 10, and damage to the stopper 10 and the locking surface 24 can be suppressed. Further, since the cord C continues to be fed out until the rotation of the cord holder 30 becomes smaller than the predetermined rotation and the locking claw 12 and the locking surface 24 engage with each other, the cord holder 30 is protruded from the case 20 without the accelerator operation. The code C has a predetermined length.

  Further, in this cord type brush cutter brush cutter head, the engaging claw 12 and the engaging surface 24 are engaged and released by the centrifugal force applied to the stopper 10, so that the feeding amount of the cord C is stabilized. Yes. That is, when the pressing force of the spring 15 is used, the feeding amount of the cord C depends on the variation of the spring 15 and aging deterioration, but the centrifugal force applied to the stopper 10 is determined by the shape of the stopper 10 and the like. The influence on the feeding amount of the code C due to variations and aging deterioration is small. Therefore, according to this cord type brush cutter brush cutter head, even when the length of the cord C is extremely shortened at a time during the operation, until the cord C reaches a predetermined length without damaging the parts. The code C can be automatically fed out.

  Further, in this cord type brush cutter brush cutter head, the protrusion 25 slides and guides the projection 13, so that the locking claw 12 can be reliably moved along the outer peripheral surface 23.

  Further, in this cord type brush cutter brush cutter head, since the spring 15 presses the locking claw 12 of the stopper 10 toward the outer peripheral surface 23, the cord C can be wound around the cord holder 30 without being disassembled. In the case of the brush cutter head for a type brush cutter, the cord C can be easily wound around the cord holder 30. In this cord type brush cutter brush cutter head, since the engaging claw 12 and the engaging surface 24 are engaged and released by the centrifugal force applied to the stopper 10, the pressing force of the spring 15 is applied to the stopper 10. It is small enough to press the locking claw 12 in the direction of the outer peripheral surface 23. For this reason, the influence of the spring 15 on the feeding amount of the cord C is extremely small.

  Further, in this cord type brush trimmer head, two through-holes 35 are provided at the outer periphery of the cylindrical portion 31 of the cord holder 30 at a radially symmetrical position, and the outer periphery of the case 20 is at a radially symmetrical position. Two cord insertion holes 28 are provided. The two through holes 35 and the two cord insertion holes 28 are arranged in a straight line at any engagement position between the locking claw 12 of the stopper 10 and the locking surface 24 of the case 20. Therefore, when winding the cord C around the cord holder 30, the two through holes 35 and the two cord insertion holes 28 can be easily arranged in a straight line, and both ends of the cord C can be easily passed through the insertion holes 28. Become.

  In this embodiment, the stopper 10 is provided on the lid 2, and the outer peripheral surface 23 and the guide portion (projection 25) are provided on the case 20. However, the stopper 10 is provided on the case 20, and the outer peripheral surface 23 and A guide portion may be provided on the lid 2.

  The cord type brush cutter head according to the present invention has been described according to the embodiments. However, the present invention is not limited to these embodiments, and may be changed as appropriate without departing from the technical idea of the present invention. Needless to say, this is applicable.

  DESCRIPTION OF SYMBOLS 1 ... Crusher head for cord type brush cutter, 2 ... Cover, 10 ... Stopper, 12 ... Locking claw, 13 ... Return part (projection), 15 ... Spring, 20 ... Case, 23 ... Outer peripheral surface, 24 ... Locking Surfaces: 25: Guide portions (projections), 28: Cord insertion holes, 30: Cord holders, 31: Cylindrical portions, 35: Through holes, 91: Mounting shafts, C: Cords, L: Shaft centers.

Claims (4)

A cord type brush cutter that cuts grass by winding both ends of a cord wound around a cord holder and protruding from the case, and rotating both ends of the cord at a high speed around the shaft center of the attachment shaft of the brush head For the brush cutter head,
Has a lid that rotates the axis around together with the cord holder, the case is rotatably disposed in the axial center around between the cord holder and lid,
A stopper having a locking claw at the tip is pivotally supported on one of the lid and the case,
On the other side of the lid or the case, an outer peripheral surface having a plurality of locking surfaces that are locked with the locking claws and rotate the case integrally with the cord holder and the lid is formed in a circular shape,
In the other side of the lid or the case, a return portion provided at the rear end of the stopper is guided,
A cord type brush cutter brush cutter, wherein a guide portion for moving the locking claw along the outer peripheral surface is provided inside the outer peripheral surface. The return part of the stopper is a protrusion protruding to the other side of the lid or the case,
The cord type brush cutter brush cutter head according to claim 1, wherein the guide portion of the stopper is a convex strip or a concave strip that slides and guides the projection.   The cord type brush cutter brush cutter according to claim 1 or 2, wherein a spring that presses the locking claw toward the outer peripheral surface is provided on the one of the lid and the case. The cord holder includes a cylindrical cylindrical portion around which the cord is wound, and two through holes are provided on the outer periphery of the cylindrical portion at symmetrical positions in the radial direction.
Two cord insertion holes are provided on the outer periphery of the case at symmetrical positions in the radial direction,
At the time of winding the cord around the cord holder, the cord is inserted into the two through holes and the two cord insertion holes, and the case and the cord holder are relatively rotated, A cord can be wound around the cylindrical portion of the cord holder;
The two through holes and the two cord insertion holes are arranged in a straight line at any engagement position of the locking claw and the locking surface. Brush cutter head for cord type brush cutter.

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