JPH0644341Y2 - Cutting blade attaching / detaching device for brush cutter - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention allows the cutting blade to be attached and detached by one-touch operation.
In addition, the present invention relates to a cutting blade attaching / detaching device that attaches a cutting blade to a brush cutter so that the cutting blade does not drop out carelessly.

[Conventional technology]

In most conventional brush cutters, the output of a small engine as a power source attached to one end of the operating main rod is input to a gear case provided at the other end of the operating main rod via a transmission shaft. The cutting blade mounted on the output shaft of is used. At this time, the cutting blade is fitted into the output shaft of the gear case so as to come into close contact with the disc-shaped upper cutting blade holder and the lower cutting blade holder that are integrally fixed to the output shaft of the gear case. It is fastened by screwing a fixing nut into a male screw portion formed on the shaft.

By the way, the cutting blade of the brush cutter is driven at a rotational speed of several thousand revolutions per minute. Therefore, if the cutting blade may fall off during high-speed rotation, the cutting blade moves around while rotating, causing an unexpected accident. In order to prevent such drop-off, there are many types in which the cutting blade is fastened to the output shaft with a double nut.

As a result, the double-nut tightening and loosening work was required when installing or replacing the cutting blade, which was very troublesome. In addition, women and women who have little knowledge of machines often cannot replace the cutting blade.

Therefore, while preventing the cutting blade from accidentally falling off,
The one that makes the installation and replacement work easy,
Various proposals have been made conventionally. For example, the present inventors have attached to the output shaft a hook unit that can slide and rotate by a shaft supported in a plane parallel to the rotation plane of the cutting blade,
We developed a device equipped with a fastening base that removably locks this hook unit, and filed a utility model registration application on September 19, 1989.

[Problems to be solved by the device]

However, the hook of the hook unit in the cutting blade attachment device proposed in the above-mentioned prior application may be affected by the attachment of dust, the precision of parts, etc., and may not be able to slide or rotate smoothly. In such a case, the hook cannot be locked to the locking portion of the fastening base, and the cutting blade cannot be fixed between the cutting blade retainer and the fastening base.

Further, since the two shafts that are operated to slide or rotate the hooks are arranged in parallel to the left and right hooks, respectively, the force for sliding or rotating the hooks is dispersed. As a result, it is not easy to use,
A large amount of force is required to attach and detach the cutting blade.

The present invention has been devised to solve such a problem, and enables the cutting blade to be attached / removed by a simpler operation and completely prevents the attached cutting blade from falling off. An object of the present invention is to provide a cutting blade attaching / detaching device that can be used.

[Means for Solving the Problems]

In order to achieve the object, the cutting blade attaching / detaching device of the present invention transmits the power of an engine provided at one end of the operating main rod to a gear case provided at the other end of the operating main rod, and an output shaft of the gear case. In a brush cutter for transmitting a driving force from 10 to a cutting blade 30, a substantially cylindrical cutting blade holder 20 spline-fitted to the output shaft 10 and the cutting blade holder 20 are clamped in cooperation with the cutting blade holder 20. A removable fastening device (40) and a locking mechanism (50) for locking the fastening device (40) to the cutting blade retainer (20) are provided. The locking mechanism (50) is a cylindrical side wall of the cutting blade restraint (20). Hole 24 drilled in
Has a locking portion 5b that fits in the front end and is rotatable about a pin 57 that pivotally supports the base end portion, and a pair of hooks 52 and 52 that are in contact with the facing inner surfaces of the hooks 52 and 52 and that face outward. A pair of attachment / detachment operation pins 51 are arranged on the same straight line so that the inner tip portions of the springs 55 for applying force and the outer surfaces of the hooks 52, 52 face each other and penetrate the side wall of the fastener 40. , 51 and.

[Action]

In the cutting blade attaching / detaching device of the present invention, in a steady state, an external force is applied to the hooks 52, 52 by the spring 55, and the fastening tool 40 is locked to the cutting blade retainer 20. Then, when the brush cutter is driven, a centrifugal force acts on the hooks 52, 52, so that the locking force acting on the fastener 40 is increased and the cutting blade 30
The sudden dropout of is completely prevented.

When removing the cutting blade 30, attach / detach operation pins 51, 5
By moving 1 inward with the force of your fingertips, the fastener 4
0 becomes removable. That is, it is possible to extremely easily remove and replace the cutting blade 30 by the touch-sensitive method.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

The cutting blade attaching / detaching device of this embodiment has a cutting blade retainer 20 mounted on the output shaft 10 protruding from the gear case, as shown in FIG. Cutting blade
30 is arranged, and the other surface of the cutting blade 30 is pressed by the fastener 40.
Further, in order to fix the fastening tool 40 to the cutting blade retainer 20, a locking mechanism 50 that penetrates the side wall of the fastening tool 40 is provided.

A spline 11 that meshes with a groove formed on the inner peripheral surface of the cutting blade retainer 20 is formed near the tip of the output shaft 10.
Further, on the tip side further from the spline 11, there is formed a projecting portion 13 in which a screw portion 12 is engraved on the inner circumference. A nut 14 whose end surface abuts on the inner step 21 of the cutting blade retainer 20 is screwed onto the protrusion 13.

The cutting blade retainer 20 is formed into a substantially cylindrical shape so that the output shaft 10 and the nut 14 can be inserted therein. Then, the flange 22 is laterally projected from the upper part of the cylindrical main body, and one surface of the flange 22 serves as a cutting blade restraining surface 23. Further, a locking hole 24 into which a tip portion of a hook 52 of a locking mechanism 50 described later is inserted is formed in the lower part of the cylindrical side wall.

A ball accommodating space 41 is formed in an annular shape on the upper end surface of the fastener 40. The ball storage space 41 has an open upper part and a lower part whose bottom becomes shallower from the inside to the outside.
It is 42. A plurality of balls 43, which are typified by bearing balls, as moving elements are accommodated along the circumferential direction of the ball accommodating space 41. A leaf spring 44 that prevents the balls 43 from falling off is provided above the ball housing space 41 that houses the balls 43. The leaf spring 44 is bent at its tip to form a bent portion 45, and the bent portion 45 is fixed to the inner wall surface of the ball housing space.

The cutting blade 30 has a hole 31 formed in the center thereof so as to be fitted to the outer periphery of the cutting blade retainer 20, and one surface of the cutting blade restraining surface of the flange 22.
Fastening tool that is in close contact with 23 and has a ball receiving space 41 on the other side
It is in contact with the upper surface of 40.

In the lower part of the fastener 40, as shown in FIG.
46 and a space 47 for attachment / detachment operation are formed as a pair. Further, the central portion of the fastener 40 is a space portion 48 for accommodating the main part of the locking mechanism 50. Number 49 is
This is a partition wall that partitions the space 48 and the mounting space 46. On the other hand, an insertion hole 4a through which the attachment / detachment operation pin 51 is inserted is formed in the side wall that partitions the attachment / detachment operation gap 47 and the central space 48.

The insertion hole 4a is a pin mounting recess opened in the attachment / detachment space 47.
A female screw 4c is engraved on the inner wall surface on the outlet side of the pin mounting recess 4b.

The locking mechanism 50 has U-shaped springs 55 such as bolts, rivets, and welding at the center of a bridge 54 that connects a pair of left and right pedestals 53, as shown in the perspective view of its constituent members in FIG. It is fixed by appropriate means. The tip of the spring 55 is bifurcated as shown, and the hook 52 is inserted into the bifurcated portion 56. Also, the spring 55
Is shaped to provide a laterally spreading force in the steady state.

This pedestal portion 53 has a pin 57 that penetrates the partition wall 49.
By inserting into the pin hole 58 drilled in 53, the input shaft
It is attached to the fastener 50 in a direction perpendicular to 10.

The base end of the hook 52 has a pin hole through which the above-mentioned pin 57 is inserted.
59 is provided, the hook 52 is arranged between the pedestal portions 53, and the pin 57 is attached to the partition wall 49 through the pin holes 58 and 59, whereby the hook 52 is rotatably arranged with respect to the pedestal portion 53. It

On the shoulder of each hook 52, as shown in FIG.
The cutouts 5a are formed alternately. This notch
5a is when the attachment / detachment operation pin 51 is pressed toward the center,
The hooks 52 allow the hooks 52 to overlap with each other while being engaged with each other. Further, the tip of the hook 52 is a tapered locking portion 5b which is fitted into the locking hole 24 formed in the side wall of the cutting blade retainer 20 described above.

Outside the hooks 52, attachment / detachment operation pins 51 facing the outer surface of the hooks 52 are arranged. The attachment / detachment operation pin 51 penetrates the insertion hole 4a formed in the fastener 40 as shown in FIG. The attachment / detachment operation pin 51 penetrates the nut 5c screwed into the female screw portion 4c engraved on the outlet-side inner wall surface of the pin mounting recess 4b and further projects outward, and the pressing portion 5d to which pressure is applied. Is formed at the tip.

A flange 5e that abuts the inner surface of the nut 5c is formed in the middle of the attachment / detachment operation pin 51. Then, the spring 5f is interposed between the inner surface of the flange 5e and the inner wall surface of the pin mounting recess 4b. Detachment operation pin by this spring 5f
An outward force is constantly applied to 51, the flange 5e is pressed against the inner surface of the nut 5c, and the attachment / detachment operation pin 51 is maintained in a steady state in which it does not contact the outer surface of the hook 52.

Note that the reference numeral 60 is used to prevent the tip of the input shaft 10 from being exposed to the outside, and to prevent the hook 52 and the spring of the locking mechanism 50 from being exposed.
This is a cover to protect the 55 from foreign matter.

Next, the operation of the attachment / detachment device described above will be described.

When using a brush cutter equipped with the specified cutting blade,
30 is secured between the cutting blade retainer 20 and the fastener 40 as shown in FIG. At this time, the cutting blade 30 is rotating at high speed together with the cutting blade retainer 20 and the fastener 40. Therefore, the ball 43
Is pushed outward by a large centrifugal force, and projects toward the cutting blade 30 side in accordance with the inclination of the bottom surface 42. As a result, the leaf spring 44
The force applied to the cutting blade 30 via the blade increases as the rotation speed increases, and the cutting blade 30 is sandwiched between the cutting blade retainer 20 and the fastener 40 with a strong force.

Further, as the rotation speed of the cutting blade 30 increases, a large centrifugal force also acts on the hook 52 and the spring 55, and the hook 52 is reliably locked by the locking hole 24 of the cutting blade retainer 20.

When the cutting blade 30 rotates at high speed, for example, when cutting grass with a large diameter,
When 30 bites, the load reduces the rotation speed of the input shaft 10. As a result, the centrifugal force acting on the ball 43 is reduced, and the ball 43 moves inward along the inclination of the bottom surface 42. Therefore, the ball 43 is cut by the leaf spring 45.
The force pressing against the cutting blade restraining surface 23 of 30 becomes small, and the cutting blade 30
Are kept loose between the cutting blade restraint 20 and the fastener 40. In this state, the power transmitted through the input shaft 10 is the cutting blade 30.
It will not be completely transmitted to, and the cutting blade 30 will not be rotated unnecessarily. Therefore, the cutting blade 30 is prevented from being damaged.

When replacing the cutting blade 30, the drive of the power source such as the engine is stopped and the input shaft 10 is kept stationary. In this state, the hook 52 is merely pushed outward by the elastic force of the spring 55. Therefore, the pin for detaching operation
A force is applied to the pressing portion 5d of 51 to move the attachment / detachment operation pin 51 toward the center portion against the force of the spring 5f.

By this movement, the inner tip of the attachment / detachment operation pin 51 comes into contact with the outer surface of the hook 52. Furthermore, pin 51 for attachment and detachment operation
Is moved inwardly, the pair of hooks 52 rotate about the pin 57 in the direction of approaching each other against the elastic force of the spring 55, and the locking portion 5b at the tip is moved from the locking hole 24. Get out. Since the notch 5a is formed on the inner shoulder of the hook 52, the hooks 52 are in a state of meshing with each other, and the locking portion 5b is completely retracted from the inner peripheral surface of the cutting blade retainer 20. . Therefore, by pulling out the fastening tool 40 in the axial direction of the input shaft 10, the fastening tool 40 can be separated from the cutting blade retainer 20.

After the fastener 40 is separated, a new cutting blade 30 is placed on the upper surface of the fastener 40. Then, while applying a force to the pressing portion 5d, the fastener 40 is inserted into the body of the cutting blade retainer 20 until it comes into contact with the lower surface of the cutting blade retainer 20. As a result, the fastener for the cutting blade retainer 20
40 positions are secured.

Then, when the pressing portion 5b is opened, the spring 5f is restored and the attachment / detachment operation pin 51 moves outward, so that the inner end portion of the attachment / detachment operation pin 51 is separated from the outer surface of the hook 52. Then, the hook 52 is spread by the elastic force of the spring 55,
The locking portion 5b at the tip fits into the hole 24. This allows
A state in which the fastening tool 40 is locked to the cutting blade retainer 20 in a regular positional relationship is obtained.

In this way, the fastening tool 40 can be easily removed from the cutting blade retainer 20 by pressing the attachment / detachment operation pin 51 inward, and the fastening tool is released in a predetermined positional relationship by releasing the pressing force. 40 can be attached to cutting blade restrainer 20. At this time, the pair of attachment / detachment operation pins 50 in FIG. 1 are arranged on the same straight line, so that the attachment / detachment operation pin 51 can be easily pushed inward by the pressing force of one hand.

Also, when the cutting blade 30 bites into a small-diameter tree, the rotation speed of the cutting blade 30 decreases due to the load as described above,
The centrifugal force of the ball 43 is reduced, and the clamping pressure of the cutting blade retainer 20 and the fastener 40 applied to the cutting blade 30 is reduced. As a result, the cutting blade 30 does not receive the driving force from the input shaft 10. Therefore, the force exerted on the locking portion 5b of the hook 52 is also reduced, and the rigid body strength required for the hook 52 having the tapered locking portion 5b is also small.

[Effect of device]

As described above, in the cutting blade attaching / detaching device of the present invention, the fastening tool 40 can be easily removed from the cutting blade retainer 20 by pressing the attaching / detaching operation pin 50 arranged on the same straight line. You can When driving the brush cutter, hook 5
Since the cutting blades 2, 52 are securely fitted into the holes 24 of the cutting blade retainer 20, the cutting blade 30 does not fall off, and the cutting blade work can be performed safely.

[Brief description of drawings]

FIG. 1 is a sectional view of the essential parts of a cutting blade attaching / detaching device according to an embodiment of the present invention, FIG. 2 is a sectional view of the essential parts of the cutting blade attaching / detaching device as seen from below, and FIG. FIG. 10; Output shaft, 20; Cutting blade restraint, 24; Hole, 30; Cutting blade, 40; Fastener, 4
a; insertion hole, 50; locking mechanism, 5b; locking portion, 51; attachment / detachment operation pin,
52; Hook, 55; Spring, 57; Pin

Claims (1)

[Scope of utility model registration request] 1. The power of an engine provided at one end of the operating main rod is transmitted to a gear case provided at the other end of the operating main rod, and a driving force is output from an output shaft (10) of the gear case to a cutting blade (3).
In the brush cutter transmitted to (0), the substantially cylindrical cutting blade retainer (20) spline-fitted to the output shaft (10) and the cutting blade (30) in cooperation with the cutting blade retainer (20). A retaining mechanism (40) for sandwiching the retaining mechanism and a retaining mechanism (50) for retaining the retaining mechanism (40) on the cutting blade retainer (20) are provided. ) Is centered on a pin (57) having a locking portion (5b) fitted at a hole (24) formed in the cylindrical side wall of the cutting blade restrainer (20) at its tip and pivotally supporting the base end. Pair of rotatable hooks (52, 52) and a spring (55) that contacts the inner surfaces of the hooks (52, 52) facing each other and applies an outward force
And a pair of attachment / detachment operation pins (51) arranged on the same straight line so that the inner tip ends face the outer surfaces of the respective hooks (52, 52) and penetrate through the side wall of the fastener (40). , 51) and a cutting blade attaching / detaching device for a brush cutter.