JPS6225483B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electric chain saw in which a cutting chain is wound around and supported by a guide bar projecting forward from a housing carrying a motor, and the chain is driven by the motor. The present invention relates to a hand guard device.

For the chain saw mentioned above, when using (cutting)
To prevent sudden accidents such as the phenomenon in which the chain guide bar violently rebounds upwards due to the cutting resistance of the chain (kickback phenomenon) or the operator's hand slipping from the front handle and coming into contact with the cutting chain. For this purpose, chain saw manufacturers are required to install a braking device to stop the cutting chain drive.

Conventionally, as disclosed in Japanese Patent Publication No. 47-47157, a braking device for the above-mentioned chain saw operates a braking mechanism provided around the outer periphery of a clutch housing by swinging a hand guard (lever arm) forward. A configuration is known in which at least a braking force is applied to stop the drive of the cutting chain. However, because the braking position is on the clutch shaft rather than the motor drive shaft, the motor continues to rotate.
Further, even if the ignition current to the power engine is cut off, the engine continues to rotate due to inertia or the like. Therefore, there was a drawback that the cutting chain could not be stopped instantaneously.

The present invention is an attempt to solve the above-mentioned conventional drawbacks, by installing a brake drum directly around the motor drive shaft before it is rotated at an increased speed by a gear train, etc., and simultaneously applying braking with a brake belt connected to a hand guard. It cuts off the motor electrical circuit. Therefore, since the brake is applied to the shaft before it rotates at an increased speed, there is no brake slip at all and instantaneous braking can be performed, resulting in high safety.

That is, it is located at the front of the housing and is pivotally supported in front of the front handle so as to be rotatable in the front-rear direction.By rotating forward, the brake belt wound around the brake drum is tightened and the brake belt is applied to the drive shaft. A control lever is integrally installed rearward from the hand guard attached to provide power, and at the same time as the hand guard is braking, the brake switch is actuated by the control lever, cutting off the motor electric circuit and stopping the motor. With this configuration, it is possible to perform a highly safe and stable braking operation by instantly stopping the rotation of the motor drive shaft by simply rotating the hand guard forward. The object of the present invention is to provide a novel hand guard device for an electric chain saw that can instantly stop the cutting chain and thereby improve safety.

Hereinafter, the present invention will be described in detail based on the illustrated embodiment. As shown in FIGS. 1 to 4, a housing 1 is long in the front-rear direction and formed in a substantially flat shape, and the upper part of the front part thereof is A front handle 2 is installed at the front, and a rear handle 3 is integrally provided at the rear.

The front end of the housing 1 is recessed with a substantially U-shaped cross section and opens forward, and the recess 4 is provided with a spike 5 having a substantially U-shaped cross section with the opening facing forward. It is fixed with screws 6 in the state, and it is inside the spike 5 and has its left and right side walls 5.
a, 5a and both side walls 1 of the housing 1
The lower end of the hand guard 7 is pivotally mounted on a, 1a with a bolt 8 so as to be rotatable in the front and back direction, and the upper end is arranged so as to be located in front of the handle 2 and protrude upward from the housing 1. I have let you.

The upper end of the hand guard 7 is connected to the housing 1
It is bent to the side so that it can be easily pressed and rotated forward, and a lock pin hole 9 that is slightly elongated in the vertical direction is provided in the approximately central recess so that a lock pin, which will be described later, can be fitted in a vertically slidable manner. Further, an operating lever 10 is integrally provided and protrudes rearward from approximately the center of the housing 2, and the operating lever 10 is inserted into the housing 1 through a hole 11 opened in the front wall 1b of the housing 2.
Pressing the actuator 12a of the brake switch 12 that protrudes inward and is fixed within the housing 1;
Or it can be pressed and released.

On the other hand, a recessed hole 13 is provided in the upper part of the front end of the housing 1, and a lock pin 1 is provided at the front end.
Lock pin holder 1 fixed through 4 in a perpendicular manner
5 is slidable in the axial direction and elastically urged forward and diagonally downward via a lock spring 16, and the lock pin 14 is fitted into the lock pin hole 9 of the hand guard 7.

In addition, long holes 17 are long in the front and back direction in both side walls 5a, 5a of the spike 5, and a recess 1 is formed in the lower part of the rear end.
7a are formed in series, and both ends of the lock pin 14 are slidably engaged in the elongated hole 17, so that the hand guard 7 is in the rear position, that is, as shown in FIG. 3A. When the lock pin 14 is in the lock pin hole 9, the lock pin 14 is moved to the rear position by the hand guard 7, thereby fitting into the recess 17a, and the spring force of the lock spring 16 is reduced. The lock spring 16 acts as a fitting force to hold the hand guard 7 in the position shown, and in this state, the operating lever 10 is moved to the brake switch 1.
2, the brake switch 12 is held in the ON state, the motor electric circuit (not shown) is kept in a state where the motor (not shown) is energized, and the hand guard 7 is moved forward from the above state. After the lock pin 14 is released from the recess 17a by a slight rotation, the hand guard 7 is rotated forward within the effective length of the elongated hole 17 to the position shown in FIG. The lock spring 16 is provided to act to hold the operating lever 10 in place, and in this state, the operating lever 10 is
Release the pressure on a and turn the brake switch 12.
It is arranged so that the motor is turned OFF, thereby cutting off the motor electric circuit and cutting off the power to the motor.

As clearly shown in FIG. 2, the braking mechanism is constructed by winding a braking belt 21, one end of which is fixed to the protrusion 19 of the housing 1 with a screw 20, around the brake drum 18 that is disposed around the motor drive shaft 22, and the other end is By tensioning or releasing the tension of the brake belt 21, a braking force can be applied to the drive shaft 22 to which the brake drum 18 is fixed, or the braking force can be released.

Therefore, the other end of the brake belt 21 is connected to the hand guard 7 by a connecting rod 23, and the brake belt 21 is tensioned by rotating the hand guard 7 forward. .

The electric chain saw to which the above hand guard device is applied is configured as follows.

An idle gear 24 and a final gear 25 are rotatably supported in the housing 1 in a mutually engaged state, and a sprocket 27 is attached to the projecting end of a final shaft 26 that projects outward from the side wall 1a of the housing 1. Fix the sprocket 27
A guide bar 29 is fixed to the side of the housing 1 with bolts 31 via a guide bar receiver 28 and protrudes forward, and a cutting chain is attached to the guide bar 29 and the sprocket 27. 30 is hung and can be driven by the sprocket 27, and the base ends of the sprocket 27 and the guide bar 29 are connected to a chain cover 32 fixed to the side of the housing 1 with the bolts 31. covered.

Further, on the other side of the housing 1, a motor M is provided.
The brake drum 18 and the fan 34 are fixed to the front end of the drive shaft 22, and the shaft bearing part 35 of the housing 1 and the end It is rotatably supported by a bearing part 37 of the cover 36 via bearings 38 and 39, and a gear 40 is carved in one end of the cover 36 that protrudes into the housing 1, and the gear 40 and the idle gear 24 are connected to each other. They are interlocked.

The electric circuit of the motor M includes a brake switch 12 and a trigger 41 provided on the rear handle 3.
The trigger 41 is a push type switch. Therefore, when the trigger 41 is pulled while connected to a power source (not shown), the switch 42 is turned on and the motor M is energized, the motor M starts, and the drive shaft 2
2 rotation is idle gear 24, final gear 2
5 to the sprocket 27, and the cutting chain 30 is driven. When the trigger 41 is pulled again, the trigger 41 returns and the switch 42 turns OFF.
However, when the power to the motor M is cut off and stopped, the driving of the cutting chain 30 is stopped.

In FIG. 3A, 45 is an oil tank provided in the housing 1, and 43 is an oil pump.The operation of the pump 43 supplies oil to the cutting chain 30 to prevent seizure during cutting.

In the above configuration, when the trigger 41 is pulled while the hand guard 7 is held in the rear position as shown in FIG. 3A, the motor M starts.
This drives the cutting chain 30, so
Cutting work can be performed in such a state.

During cutting, the above-mentioned backlash phenomenon,
If your hand slips from the front handle 2 during work and is about to come into contact with the cutting chain 30, it is necessary to stop the chain 30 drive instantly to prevent an accident. By rotating the brake belt forward, the brake belt 21 is tensioned and the brake drum 18 fixed to the motor drive shaft 22 is tightened.
By coming into pressure contact with the drive shaft, a braking force is applied to the drive shaft. In other words, by fixing the brake drum to the motor shaft that is not being rotated at increased speed, it is possible to stop the motor instantly without any braking slip. At this time, the operating lever 10 is moved backward, releasing the pressure on the actuator 12a, which activates the brake switch 12 and interrupts the motor electric circuit, cutting off the power to the motor M. The motor M stops.

In other words, by tilting the hand guard 7 forward,
Braking of the drive shaft 22 and stopping of the motor M are performed simultaneously. Therefore, the cutting chain drive can be stopped instantaneously.

After stopping the chain 30 in this way, if you want to drive it again, rotate the hand guard 7 backwards, and the brake switch 12 will be turned on by the operation lever 10, so the motor will not be turned on. As a result of the circuit being closed, the motor M starts at the same time as the brake is released, and the disconnection chain 30
can be driven. In this case, it is not necessary to operate the trigger 41.

As explained above, the hand guard device for an electric chainsaw according to the present invention is configured and operates, so that the motor M is stopped at the same time as the hand guard 7 is rotated forward and the brake is applied to the motor M. Therefore, compared to the conventional configuration in which the brake is applied to the clutch housing part while the motor is rotating, the brake is applied directly to the motor drive shaft, so that the motor is stopped completely in an instant, and the operating lever 10 that operates the brake switch 12 is teeth,
Since the brake switch 12 is provided integrally with the hand guard 7, the operation of the brake switch 12 is performed directly, so there is no time delay in stopping and braking the motor M, and the hand guard 7 can be operated simply by moving the brake switch 12 forward. Since the chain only rotates to and does not rotate in multiple stages, it has good operability and stable brake operation, and the chain drive can be stopped instantly.
Since the intended purpose of improving safety can be achieved and the configuration can be simplified, safety can be ensured over a long period of time without failure, and moreover, it can be provided at a low cost.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional plan view of a chain saw equipped with a hand guard device according to the present invention, Figure 2 is a right side view of the same electric chain saw with the motor and motor case removed, and Figure 3 A is the same electric chain saw. Fig. 4 is a vertical side view of the chain saw with the hand guard in the backward position; FIG. 4 is a partially sectional front view showing the mounting structure of the hand guard as viewed from the right side in FIG. 3A; 1...Housing, 2...Front handle, 7...
Hand guard, 10... Operation lever, 12... Brake switch, 18... Brake drum, 2
1...Brake belt, 29...Guide bar, 30...
...Cutting chain, M...Motor.

Claims (1)

[Claims] 1. A hand guard device for an electric chain saw in which a cutting chain is wound around and supported by a guide bar protruding forward from the housing, and the chain is driven by a motor supported on the housing. , equipped with a hand guard attached to the front of the front handle so that it can rotate freely in the front-rear direction, and the forward rotation applies braking force to the brake drum fixed to the drive shaft via the brake belt. A control lever is integrally protruded rearward from the hand guard and connected to the brake switch fixed to the housing so that it can be turned on and off, and the brake switch is operated in synchronization with the braking operation of the hand guard. A hand guard device for an electric chainsaw, characterized in that the hand guard device for an electric chainsaw is configured to interrupt the motor electric circuit and stop the motor by activating the motor.