JP2006325525A - Bushing rotator used in bush cutter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly and surely carry out the delivery action of a blade. <P>SOLUTION: In the bushing rotator 11 that is equipped with a rotatable tubular bobbin 14 on which a flexible linear blade 15 is wound and with a clutch 16 which is vertically arranged in the inner peripheral side of the bobbin 14 and is slidable in the rotary axial direction of the bobbin 14, latching pawls 28 project from the inner peripheral surface of the bobbin 14, control pawls 32a which abut on the latching pawls 28 in a state of the falling clutch and control the rotation of the bobbin 14 projects from the outer peripheral surface of the clutch 16. The upper surfaces of the latching pawls 28 and the lower surface of the control pawls 32 facing the surfaces of the latching pawls 28 in a state of the rising clutch have gradually downward inclining tapered faces toward in the unwinding direction of the flexible linear blade 15 from the bobbin. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a brush cutter for use in a brush cutter for carrying a grass cutter by an operator, and more specifically, a state in which a flexible linear blade is projected radially by centrifugal force generated by high-speed rotation. It is related with the brush cutting rotary body which cuts grass.

  2. Description of the Related Art Conventionally, as a brush cutter for use in grass cutting, a brush blade device in which cord blades protrude radially is attached to a drive shaft at the tip of an operating rod. In this type of brush cutting operation, the drive shaft is rotated at a high speed by an engine or motor so that the flexible cord blade protrudes in a direction substantially perpendicular to the rotation circumference by centrifugal force. Rotate to cut the grass into chopped pieces. Further, when the cord blade hits an obstacle, the cord blade is bent and passed in such a manner that its root portion precedes the rotation direction, and maintains the required high speed rotation. If the cord blade is worn out and shortened due to the grass cutting work being performed for a long time, the cord blade wound around the bobbin in the brush cutting device is fed out to continue the brush cutting operation. ing.

For example, in the cutting blade device shown in FIG. 8, the switching member 1 and the bobbin 2 are relatively movable in the rotational axis direction, and the switching member 1 is biased downward by the coil spring 3 (Patent Document 1). reference). In the normal state in which the switching member 1 is lowered, the locking claw 1a that protrudes with a gap on the outer peripheral surface of the switching member 1 is a lower lock that protrudes with a gap on the lower side of the inner peripheral surface of the bobbin 2. Engaged with the claw 2a. On the other hand, when the switching member 1 is struck against the ground and rises relative to the bobbin 2, the engagement between the locking claw 1a and the lower locking claw 2a is released, and the bobbin 2 rotates at a required angle by centrifugal force. After that, the locking claw 1a comes into contact with the upper locking claw 2b protruding at an interval above the inner peripheral surface of the bobbin 2 and stops. Thereafter, when the load on the switching member 1 from the ground is removed, the switching member 1 is lowered relative to the bobbin 2 by the biasing force of the coil spring 3, and the engagement between the locking claw 1a and the upper locking claw 2b. The engagement is released, the bobbin 2 is rotated by a required angle by centrifugal force, and the locking claw 1a comes into contact with the next lower locking claw 2a and is stopped.
JP-A-6-30626

  However, if the load on the switching member 1 is removed before the bobbin 2 is sufficiently rotated after the switching member 1 is pushed up, for example, because it is rotating at a low speed, the locking claw 1a of the switching member 1 is released. Since the biasing force of the coil spring 3 stops the state in which it is pressed against the upper surface of the lower locking claw 2a of the bobbin 2, the switching member 1 may not be able to return to the lowered state, and the feeding operation of the cord blade 4 is smooth. There is a problem that is not done.

  The present invention has been made in view of the above problems, and an object of the present invention is to allow a blade feeding operation to be performed smoothly and reliably.

  The present invention relates to a brush cutter comprising a rotatable cylindrical bobbin around which a flexible wire blade is wound, and a clutch which is disposed on the inner peripheral side of the bobbin and which can slide up and down along the rotation axis direction of the bobbin. In the rotating body, a locking claw protrudes from the inner peripheral surface of the bobbin, while a surface of the clutch that faces the inner peripheral surface of the bobbin is in contact with the locking claw in a clutch lowered state. A restricting claw for restricting the rotation of the bobbin relative to the clutch protrudes, and the upper surface of the engaging claw and the lower surface of the restricting claw that faces the upper surface of the engaging claw when the clutch is lifted are There is provided a brush cutter rotator for use in a brush cutter characterized by a tapered surface that gradually slopes downward in the bobbin counter-winding direction of the blade.

  In this way, when the clutch slides and descends relative to the bobbin and the lower surface of the locking claw is placed on the upper surface of the regulating claw, the locking claw and the regulating claw Since the inclined tapered surfaces are in contact with each other, the bobbin is smoothly guided in the rotational direction without being caught. Therefore, the feeding operation of the flexible wire blade can be performed smoothly and reliably.

  On the inner peripheral surface of the bobbin, a second locking claw protrudes above the locking claw, while the surface of the clutch facing the inner peripheral surface of the bobbin is above the regulating claw. When the second restriction pawl is protruded and the bobbin is rotated by a predetermined angle in a state where the restriction pawl is separated upward from the locking pawl due to the raising of the clutch, the second locking pawl is moved to the second The bobbin rotation with respect to the clutch may be restricted by abutting against the restriction pawl.

  In this way, in the normal state where the clutch is lowered relative to the bobbin, the side surface of the clutch restricting claw contacts the side surface of the locking claw of the bobbin and is locked. When the bobbin is relatively raised and rotated by a required angle, the side surface of the second locking claw comes into contact with the side surface of the second regulating claw and is stopped. That is, when the clutch is raised, the second restricting claw positioned above the restricting claw is in contact with the second locking claw, so that the upward movable range of the clutch is small. However, the rotation of the bobbin can be reliably controlled. In addition, the 2nd control nail | claw of a clutch may be provided integrally with the said control claw, and may be provided away.

  A clearance may be formed between the upper surface of the restriction claw of the clutch and the lower surface of the second locking claw of the bobbin in a state where the clutch is located at the top dead center.

  In this way, when the bobbin rotates by raising the clutch, no frictional resistance is generated between the second locking claw of the bobbin and the regulating claw of the clutch, and the flexible linear blade is fed out. Becomes even smoother.

  The restricting claw has a stepped portion formed by cutting out a side surface from below, while the locking claw abuts the stepped portion of the restricting claw in a clutch lowered state to restrict rotation of the bobbin. You may have a part.

  In this case, when the locking claw of the bobbin is brought into contact with and locked with the restriction claw of the clutch, the corner portion of the locking claw is contacted from two directions by the step of the restriction claw. Improves stability.

  The clutch may be metallic.

  If it does in this way, the intensity | strength of the clutch which receives an impact by hitting on the ground etc. is fully ensured, and a product life can be extended.

  The bobbin may include a cylindrical portion, a flange portion that protrudes in a bowl shape from the cylindrical portion, and a notch groove that is formed at a peripheral edge of the flange portion and can temporarily lock the flexible linear blade. Good.

  In this way, when assembling the flexible wire blade around the bobbin and storing it in the case, it becomes possible to temporarily hold the flexible wire blade between the notch grooves and temporarily fix it. improves.

  According to the present invention, when the once lifted clutch descends again, the bobbin locking claw and the clutch regulating claw are brought into contact with each other with the tapered surfaces inclined with respect to the rotation direction. Guided smoothly in the rotational direction without being caught, the flexible linear blade can be smoothly and reliably fed out.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is an exploded perspective view showing a brush cutter rotating body 11 used in the brush cutter 10 according to the present embodiment. FIG. 2 is a sectional view of the brush cutter rotator 11. 3A is a top view of the bobbin 14, FIG. 3B is a cross-sectional view, and FIG. 3C is a bottom view. FIG. 4 is a development of a main part of the outer peripheral surface of the bobbin 14. 5A is a top view of the clutch 16, FIG. 5B is a side view, and FIG. 5C is a cross-sectional view. FIG. 6 is a development view of the main part of the outer peripheral surface of the clutch 16. FIGS. 7A to 7D are diagrams for explaining the locking operation of the bobbin 14 and the clutch 16.

  As shown in FIGS. 1 and 2, the brush cutter rotator 11 of this embodiment is fixed to the drive shaft 20 at the tip of the operating rod 19 to constitute a portable brush cutter 10. The brush cutter rotating body 11 includes a bobbin 14 in which a flexible wire blade 15 is wound in an annular space S formed by an upper case 12 and a lower case 13 so as to be rotatable. A clutch 16 that is slidable in the direction of the rotation axis L of 14 and rotates together with the upper case 12 is disposed. The clutch 16 is urged by a spring 17 so that the lower end side protrudes outside from the opening 13 a of the lower case 13.

  The upper case 12 includes a resin case main body 21, a metal mounting seat 22 having a shaft through hole 22b through which the drive shaft 20 passes, and a blade through hole 23a through which the flexible linear blade 15 passes. And a metallic guide body 23 having The case main body 21 includes an annular upper wall portion 21a, an outer cylindrical wall portion 21b protruding downward from the outer peripheral end of the upper wall portion 21a, and an inner cylindrical wall portion protruding downward from the inner peripheral end of the upper wall portion 21a. An annular space S having a lower surface opening is formed.

  The upper wall portion 21a has an opening 21g formed in the center, and an engaged groove 21d in which the inner peripheral edge of the opening 21g is cut out in an annular shape. The engaged groove 21 d is fitted with a flange portion 22 a that protrudes laterally from the peripheral edge of the mounting seat 22, and the opening 21 g is closed by the mounting seat 22. The outer cylinder wall portion 21b includes a lock piece 21e for locking the lower case 13, a pair of opposed slit portions 21h cut out above the lower end edge, and a rectangular hole communicating with the slit portion 21h. Part 21i. A guide body 23 communicating with the slit portion 21h is fitted into the hole portion 21i. The guide body 23 has a rectangular blade passage hole 23a and a cutout portion communicating with the slit portion 21h formed at the lower end edge. A plurality of slide grooves 21f that are recessed in the direction of the rotation axis L are formed on the outer peripheral surface of the inner cylindrical wall portion 21c at intervals in the circumferential direction.

  The lower case 13 is made of resin, and includes a bottom wall portion 13a, an opening 13b drilled in the center of the bottom wall portion 13a, and a locked portion (not shown) that is engaged with the lock piece 21e of the upper case 12. have.

  The bobbin 14 is made of resin, and as shown in FIGS. 3A to 3C and FIG. 4, the cylindrical portion 34, the upper flange portion 24 protruding in a bowl shape from the upper end of the cylindrical portion 34, and the cylindrical portion 34 A lower flange portion 25 projecting in a bowl shape from the lower end, an annular partition wall 26 projecting in a bowl shape from the outer peripheral surface at the center in the height direction of the cylindrical portion 34, and an upper end of the inner peripheral surface of the cylindrical portion 34 A plurality of upper locking claws 27 (second locking claws) protruding at intervals in the direction and a plurality of lower locking claws protruding at intervals in the circumferential direction at the lower end of the inner peripheral surface of the cylindrical portion 34 28 (locking claw).

  The lower locking claw 28 is offset with the circumferential position shifted from the upper locking claw 27 and is wider in the circumferential direction than the upper locking claw 27. Note that the circumferential width of the adjacent gap of the lower locking claw 28 is substantially the same as the circumferential width of the upper locking claw 27. The upper surface of the lower locking claw 28 is a tapered surface 28a that is gradually inclined downward in the anti-winding direction of the flexible linear blade 15, and the intersection of the tapered surface 28a and the side surface 28b is a corner portion 28c. ing. The upper latching claw 27 and the lower latching claw 28 have substantially the same amount of protrusion in the radial direction, and the surface on the radial center side is a curved surface along the cylindrical portion 34.

  On the peripheral edges of the upper flange portion 24 and the lower flange portion 25, a notch groove 24a for temporarily locking the end side of the flexible wire blade 14 is formed at a required position. On the periphery of the partition wall 26, a hook groove 26a for press-fitting the folded portion of the flexible wire blade 14 is formed.

  The flexible wire blade 15 is a cord blade made of resin (for example, nylon) and is wound around the outer periphery of the bobbin 14 in a state where the folded portion is press-fitted into the hooking groove 26a of the partition wall 26. An end portion of the blade 15 passes through the blade through hole 23a of the upper case 12 and is led out to the outside. When the flexible wire 15 is allowed to pass through the blade through hole 23a, the flexible wire blade 15 can be easily passed through the blade through hole 23a by passing the flexible wire blade 15 through the slit portion 21h.

  The clutch 16 has a bottomed cylindrical shape integrally formed of metal, and as shown in FIGS. 5A to 5C and FIG. 6, a cylindrical portion 29 and a bottom portion 30 that closes the lower end of the cylindrical portion 29. And have. At the center in the height direction of the outer peripheral surface of the cylindrical portion 29, an annular step portion 31 is formed that contacts the upper peripheral edge of the opening 13 b in a state where the bottom 30 side of the clutch 16 is inserted into the opening 13 b of the lower case 13. . At a position above the annular step portion 31 on the inner peripheral surface of the cylindrical portion 29, a ridge portion 33 protruding in the direction of the rotation axis L is formed with an interval in the circumferential direction. That is, the protruding portion 33 is fitted into the slide groove 21f of the inner cylindrical wall portion 21c, so that the clutch 16 can be slid up and down and is externally fitted to the inner cylindrical wall portion 21c so as to rotate together with the upper case 12. The On the upper side of the outer peripheral surface of the cylindrical portion 29, a plurality of rotation restricting bodies 32 are provided projecting at intervals in the circumferential direction. The widths of adjacent circumferential clearances of the respective rotation restrictors 32 are equal to or greater than the circumferential width of the upper locking claw 27 of the bobbin 14 so that the clutch 16 can be inserted from above the bobbin 14. ing.

  The rotation restricting body 32 has a lower restricting claw 32a (a restricting claw) and an upper restricting claw 32b (a second restricting claw) protruding upward from one side end of the lower restricting claw 32a. A stepped portion 32c cut out from below is formed on the side surface of the upper restricting claw 32b forming side. The upper end of the upper restricting claw 32b is positioned at the same height as the upper end of the cylindrical portion 29, and the circumferential width of the lower restricting claw 32a is larger than the circumferential width of the upper restricting claw 32b. .

  The lower surface of the lower restricting claw 32 a is a tapered surface 32 d that is inclined along the tapered surface 28 a of the lower locking claw 28 of the bobbin 14. The circumferential length of the tapered surface 32d of the lower restricting claw 32a is shorter than the circumferential length of the tapered surface 23a of the lower locking claw 28 of the bobbin 14. The upper surface 32e of the lower restricting claw 32a is a horizontal plane. The outer peripheral surface of the lower restricting claw 32 a is a curved surface along the inner peripheral surface of the bobbin 14. The circumferential width of the restricting claw 32 is substantially the same as the circumferential width of the lower locking claw 28 of the bobbin 14.

  As shown in FIG. 2, the spring 17 is arranged so as to urge the space between the lower surface of the mounting seat 22 of the upper case 12 and the upper surface of the bottom portion 30 of the clutch 16 in the separating direction. A screw is engraved on the outer peripheral surface of the drive shaft 20, and the drive shaft 20 passes through the shaft through hole 22 b of the mounting seat 22 of the upper case 12 and is fastened and fixed by a nut 18.

Next, the feeding operation of the flexible linear blade 15 of the brush cutter rotating body 11 will be described with reference to FIG. (Note that in FIG. 7, the portion of particular interest is hatched.)
When the operator holds the operation rod 19 and the mowing rotary body 11 is lifted off the ground for the mowing operation, the clutch 16 is lowered relative to the bobbin 14 by the urging force of the spring 17, and FIG. As shown to (a), the corner | angular part 28c of the lower latching claw 28 of the bobbin 14 is latched by the level | step-difference part 32c of the lower regulation claw 32a of the clutch 16, and the rotation of the bobbin 14 is controlled.

  When the flexible wire blade 15 is worn out and shortened by the brushing operation, the operator operates the operating rod 19 so that the bottom 30 of the clutch 16 protruding outside from the opening 13b of the lower case 13 is on the ground. Slam. Then, the clutch 16 rises relative to the bobbin 14 against the spring 17, and the locking of the lower locking claw 28 and the lower regulating claw 32a is released as shown in FIG. 7B. . Then, the bobbin 14 is rotated by a predetermined angle by the rotational centrifugal force, and the flexible linear blade 15 is drawn out from the blade through hole 23a. When the bobbin 14 rotates by a predetermined angle, as shown in FIG. 7C, the upper locking claw 27 comes into contact with the side surface of the upper restriction claw 32b and stops, and the rotation of the bobbin 14 is restricted. When the clutch 16 is located at the top dead center, a clearance is formed between the upper surface 32e of the lower restriction claw 32a of the clutch 16 and the lower surface of the upper locking claw 27 of the bobbin 14. When the bobbin 14 rotates from FIG. 7B to FIG. 7C, frictional resistance is not generated between the lower regulating claw 32a and the upper locking claw 27.

  Next, when the load from the ground is released and the clutch 16 is lowered again by the urging force of the spring 17, as shown in FIG. 7D, the tapered surface 28 a of the lower locking claw 28 of the bobbin 14, and the clutch 16 The tapered surfaces 32d of the lower regulating claws 32a are in contact with each other at the inclined surfaces. Then, the tapered surface 28a of the lower locking claw 28 is slid by centrifugal force along the inclination of the tapered surface 32d of the lower regulating claw 32a, and the bobbin 14 is smoothly guided in the rotation direction. Next, when the bobbin 14 rotates by a predetermined angle, as shown in FIG. 7A, the corner portion 28c of the lower locking claw 28 of the bobbin 14 comes into contact with the stepped portion 32c of the lower regulating claw 32a of the clutch 16 and stops. Returning to the state, the rotation of the bobbin 14 is restricted.

  According to the above configuration, the upper surface of the lower locking claw 28 of the bobbin 14 is the tapered surface 28a, and the lower surface of the lower restriction claw 32a of the clutch 16 is the tapered surface 32d. When the bobbin 14 is lowered relative to the bobbin 14, the bobbin 14 rotates smoothly, and the flexible wire blade 15 can be smoothly and reliably fed. Further, since the clutch 16 is made of metal, even if it is hit against the ground and repeatedly subjected to an impact, sufficient strength is ensured and a long life is achieved. Further, when the flexible wire blade 15 is wound around the bobbin 14 and accommodated in the cases 12 and 13, the end side of the flexible wire blade 15 is formed in the notch grooves 24a and 25a of the flange portions 24 and 25. Since it becomes possible to pinch and temporarily lock, the assembling workability of the brush rotary body 11 is also improved.

  As described above, the brush cutter rotator used in the brush cutter according to the present invention has an excellent effect of enabling smooth and reliable feeding of the flexible linear blade. Suitable for application to rotating bodies.

It is a disassembled perspective view which shows the brush cutter rotary body used for the brush cutter which concerns on embodiment of this invention. It is sectional drawing of the brush cutter rotary body shown in FIG. (A) is a top view of the bobbin which the brush cutter rotary body shown in FIG. 1 has, (b) is a sectional view, and (c) is a bottom view. FIG. 4 is a main part development view of the outer peripheral surface of the bobbin shown in FIG. 3. (A) is a top view of the clutch of the brush cutter rotator shown in FIG. 1, (b) is a side view, and (c) is a cross-sectional view. FIG. 6 is a main part development view of the outer peripheral surface of the clutch shown in FIG. 5. (A)-(d) is drawing explaining the latching operation | movement of the bobbin and clutch which the brushing rotary body shown in FIG. 1 has. It is a disassembled perspective view which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Brush cutter 11 Brush cutter rotary body 12 Upper case 13 Lower case 13b Opening 14 Bobbin 15 Flexible wire blade 16 Clutch 17 Spring 18 Nut 19 Operating rod 20 Drive shaft 23a Blade through hole 24 Upper flange portion 24a, 25a Notch groove 25 Lower flange 27 Upper locking claw (second locking claw)
28 Lower locking claw (Locking claw)
28a Tapered surface 31 Annular step 32a Lower restriction claw (regulation claw)
32b Upper restriction claw (second restriction claw)
32c Stepped portion 32d Tapered surface 32e Upper surface

Claims (6)

In a brush cutter rotating body comprising a rotatable cylindrical bobbin around which a flexible linear blade is wound, and a clutch which is arranged on the inner peripheral side of the bobbin and which can slide up and down along the rotation axis direction of the bobbin,
A locking claw projects from the inner peripheral surface of the bobbin, while the surface of the clutch facing the inner peripheral surface of the bobbin contacts the locking claw in a lowered state of the clutch and A restricting claw that restricts the rotation of the bobbin is projected,
The upper surface of the locking claw and the lower surface of the regulating claw that faces the upper surface of the locking claw when the clutch is raised are gradually inclined downward in the bobbin anti-winding direction of the flexible linear blade. A brush cutter rotator for use in a brush cutter having a tapered surface. On the inner peripheral surface of the bobbin, a second locking claw protrudes above the locking claw, while the surface of the clutch facing the inner peripheral surface of the bobbin is above the regulating claw. A second restricting claw is provided,
When the bobbin is rotated by a predetermined angle with the restricting claw separated upward from the locking claw due to the raising of the clutch, the second locking claw comes into contact with the second restricting claw and The brush cutter rotating body used for a brush cutter according to claim 1, wherein the bobbin is restricted from rotating.   The clearance is formed between the upper surface of the restriction claw of the clutch and the lower surface of the second locking claw of the bobbin in a state where the clutch is located at a top dead center. A brush cutter for use in the brush cutter according to 2. While the regulation claw has a stepped portion formed by cutting a side surface from below,
The said latching nail | claw has a corner | angular part which contact | abuts to the said level | step-difference part of the said control nail | claw in a clutch lowering state, and controls the rotation of the said bobbin. Rotating body.   The brush cutter for use in a brush cutter according to any one of claims 1 to 4, wherein the clutch is metallic.   The bobbin includes a cylindrical part, a flange part protruding in a bowl shape from the cylindrical part, and a notch groove formed on the periphery of the flange part and capable of temporarily locking the flexible wire blade. A brush cutter rotating body used in the brush cutter according to any one of claims 1 to 5.

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