Patent Description:
There is a conventional electric chain saw including a body case having a motor therein, a battery mounted in a rear end part of the body case, and a top handle formed on an upper part of the body case (see <CIT> and <CIT>, for example). Such a chain saw is allowed to have a larger battery than a case where a battery is accommodated in the body case.

The chain saw disclosed in <CIT> described above is configured such that a power switch is switched on/off every time a hand guard attached to a front part of the body case is tilted. When the power switch is on, the motor is driven, and when the power switch is off, the motor is stopped.

Further, the chain saw described in <CIT> includes a power switch arranged on a front side of a gripping part of the top handle.

When an operator works with the conventional chain saw as disclosed in <CIT>, the operator is required to hold the top handle with the right hand and to hold a side handle with the left hand. In the conventional chain saw, the operator is required to take the left hand off the side handle to manipulate the hand guard so as to switch on/off the power switch during operation. Therefore, it is difficult for the operator to manipulate the power switch during operation.

Further, in the conventional chain saw as described in <CIT>, there is no space for placing the pad of the thumb on the front side of the gripping part, so that, when the operator grips the top handle, the operator is required to put the tip of the thumb under the top handle. When the top handle is gripped in this way, the chain saw is less secured to cause a problem of poor working efficiency.

The present invention intends to provide an electric power work device to solve the above-described problems, which allows an operator to stably grip a top handle and to manipulate a power switch while the operator holds the body case with both hands so that the operator can work smoothly.

An aspect of the present invention is to provide an electric power work device comprising: a body case; a work tool protruding forward from a front side with respect to the body case; a motor driving the work tool; and a battery supplying power to the motor, wherein the motor is accommodated in the body case and the battery is detachably attached to a rear side with respect to the body case, a top handle is extended in a longitudinal direction at an upside with respect to the body case, the top handle includes, on an upper surface of a front part thereof, a thumb rest and a power switch which drives the motor in an on-state and stops the motor in an off-state; and wherein the top handle includes a gripping part, the thumb rest is an area on which, in use, a pad of the thumb is placed when an operator grips the gripping part, and the thumb rest is arranged on a longitudinal axis running through a center in a lateral direction of the gripping part, the power switch is arranged on a right side in a lateral direction of the thumb rest, the thumb rest and the power switch are arranged on a recessed surface formed on an upper surface of the top handle, the thumb rest being a portion of the recessed surface, the recessed surface includes a protruding part protruding rightward with respect to a right side surface of the gripping part, and the power switch is arranged on the protruding part of the recessed surface.

With the electric power work device of the present invention, when the operator grips a gripping part, the pad of the thumb is placed on the thumb rest so that the operator can stably grip the top handle.

Further, with the electric power work device of the present invention, the operator can switch on/off the power switch with the thumb while gripping the top handle. Therefore, after the operator turns off the power switch to stop the motor while gripping the top handle during operation, the operator can turn on the power switch while gripping the top handle, to promptly resume the operation.

As described above, with the electric power work device of the present invention, the operator can stably grip the top handle and can switch on/off the power switch while holding the electric power work device with both hands. Accordingly, the operator can work smoothly, and working efficiency is improved.

Further, the thumb rest is arranged near the power switch. Therefore, even if the operator turns off the power switch by mistake during operation, the operator can easily turn on the power switch again while gripping the top handle.

Still further, in the electric power work device of the present invention, the power switch is arranged on a side of the thumb rest so that the length in the longitudinal direction of the top handle is decreased.

A description will be given of an example of an embodiment of the present invention in detail, with reference to the drawings as appropriate.

In the present embodiment, a configuration, in which the present invention is applied to a chain saw to cut a tree, a plate, or the like, will be described as an example. In the following description, a cutting part of the chain saw is on the front side with reference to the longitudinal (front-rear) direction, and a top handle thereof is on the upper side with reference to the vertical (up-down) direction.

As shown in <FIG>, a chain saw <NUM> includes a body case <NUM>, a cutting part <NUM> set to the body case <NUM>, a motor <NUM> to drive the cutting part <NUM>, and a battery <NUM>. In the chain saw <NUM>, the battery <NUM> attached to the body case <NUM> supplies power to the motor <NUM> so as to drive the cutting part <NUM>.

As shown in <FIG>, the body case <NUM> includes a body part <NUM> formed of a resin box, and a top handle <NUM> formed on the upper side of the body part <NUM>. Thus, the top handle <NUM> is formed on an upper part of the body case <NUM>. Further, a side handle <NUM> is attached to the left side surface of the body case <NUM>.

As shown in <FIG>, the motor <NUM> is accommodated in a front part of the body part <NUM>. A battery attachment part <NUM>, in which the battery <NUM> is detachably attached, and is formed in the rear part of the body part <NUM>.

The motor <NUM> is a popular electric motor. An output shaft <NUM> of the motor <NUM> extends in the lateral direction.

In addition to the motor <NUM>, a control board (not shown) to control the driving of the motor <NUM> and a drive mechanism such as a driving gear (not shown) coupled to the output shaft <NUM> of the motor <NUM> are accommodated in the front part of the body part <NUM>.

The battery attachment part <NUM> is formed on the rear end surface of the body part <NUM>. The battery attachment part <NUM> includes a holding part <NUM> to hold the battery <NUM> and a battery case <NUM> to accommodate a lower part of the battery <NUM>.

The holding part <NUM> is formed to have a rear end part of the body part <NUM> and a part in a plate shape extending upward from the rear end part of the body part <NUM>. The holding part <NUM> is inclined such that a lower part thereof is located forward with respect to an upper part thereof. As shown in <FIG>, the rear surface of the holding part <NUM> is an inclined surface which is gradually displaced forward as extending from the upper end to the lower end.

The holding part <NUM> is provided, on the rear surface thereof, with an attachment/detachment mechanism <NUM> to attach or detach the battery <NUM>. The attachment/detachment mechanism <NUM> includes guide members through which the battery <NUM> is fitted in the vertical direction and a support member (not shown) to support the battery <NUM> from below.

When the battery <NUM> is mounted in the holding part <NUM>, the battery <NUM> is slid downward along the attachment/detachment mechanism <NUM> to mount the battery <NUM> in the holding part <NUM> as shown in <FIG>.

The battery <NUM> is a popular battery, having a rechargeable battery such as a lithium ion storage battery accommodated in a rectangular parallelepiped case extending in the vertical direction, as shown in <FIG>.

As shown in <FIG>, the battery <NUM> is formed to have a height higher than that of the rear part of the body part <NUM>. The battery <NUM> of the present embodiment is formed larger than a battery accommodatable in the body case <NUM>. The battery <NUM> has a sufficiently high power and charging capacity suitable for operation.

In a state where the battery <NUM> is mounted in the holding part <NUM>, the battery <NUM> is arranged in the body case <NUM> such that the longitudinal direction of the battery <NUM> corresponds to the height direction of the body case <NUM>. Further, the battery <NUM> mounted in the holding part <NUM> is formed larger than the rear part of the body part <NUM>. The battery <NUM> is arranged in the vertical direction to stride across a central part in the height direction of the rear part of the body part <NUM>. The upper end of the battery <NUM> protrudes above the rear end of the top handle <NUM>.

Further, the holding part <NUM> includes an ejection mechanism (not shown) to be used for removing the battery <NUM> from the battery attachment part <NUM>. While the battery <NUM> is mounted in the holding part <NUM>, a lever provided on an upper part of the battery <NUM> is manipulated to activate the ejection mechanism, to push up the battery <NUM>.

Still further, as shown in <FIG>, the holding part <NUM> includes a metal connection terminal <NUM> on the rear surface thereof. The connection terminal <NUM> is electrically connected to the control board and the motor <NUM> (see <FIG>). Once the connection terminal of the battery <NUM> is connected to the connection terminal <NUM> of the holding part <NUM>, the battery <NUM> supplies power to the control board and the motor <NUM>.

As shown in <FIG>, the battery case <NUM> is formed at a lower end part of the battery attachment part <NUM>. The battery case <NUM> is a cylindrical part to accommodate the lower part of the battery <NUM>. The lower part of the battery <NUM> is inserted into the battery case <NUM>.

As shown in <FIG>, the body part <NUM> is set up, on a right side part thereof, with the cutting part <NUM> protruding forward. The cutting part <NUM> is a work tool for cutting operation and includes a guide bar <NUM> and a saw chain <NUM>.

The guide bar <NUM> is a member in a plate shape extending in the longitudinal direction, and a rear end part of the guide bar <NUM> is attached to the right side part of the body part <NUM>.

The saw chain <NUM> in an annular shape is wound around the outer periphery of the guide bar <NUM>. A rear end part of the saw chain <NUM> is engaged with the drive gear coupled to the output shaft <NUM> of the motor <NUM>.

When the motor <NUM> is driven to rotate the drive gear (not shown), the saw chain <NUM> rotates along the outer periphery of the guide bar <NUM>.

As shown in <FIG>, the top handle <NUM> is formed to continue to the upper surface of the body part <NUM> and extends in the longitudinal direction above the body part <NUM>.

The top handle <NUM> includes a front end part <NUM> protruding upward from a front end part of the upper surface of the body part <NUM>.

The top handle <NUM> includes a rear end part <NUM> coupled to an upper end part of the holding part <NUM> of the battery attachment part <NUM>. In a state where the battery <NUM> is mounted in the holding part <NUM>, the upper end part of the battery <NUM> protrudes above the rear end part of the top handle <NUM>.

The top handle <NUM> includes a gripping part <NUM> extending in the longitudinal direction between the front end part <NUM> and the rear end part <NUM>. The gripping part <NUM> is slightly inclined obliquely downward as extending from the front end part <NUM> toward the rear end part <NUM>.

The gripping part <NUM> is a part to be gripped by the operator when the operator holds the chain saw <NUM>. The operator puts the hand into a space between the gripping part <NUM> and the upper surface of the body part <NUM>.

The gripping part <NUM> includes a trigger lever 43a as operating part to increase or decrease the rotation speed of the saw chain <NUM> and a lock release lever 43b to unlock the trigger lever 43a, in a state where the operator grips the gripping part <NUM>.

As shown in <FIG>, the side handle <NUM> extends in the longitudinal direction from a front part to a rear part on the left side surface of the body case <NUM>. The side handle <NUM> is formed of a bent columnar member.

A front end part of the side handle <NUM> is attached on the left side surface of the front end part <NUM> of the top handle <NUM>. A rear end part of the side handle <NUM> is positioned rearward and downward with respect to the output shaft <NUM> of the motor <NUM>, and is attached on the left side wall of the battery case <NUM>.

The side handle <NUM> is curved between the front end part and the rear end part thereof to bulge outward with respect to the left side surface of the body case <NUM> (see <FIG>).

As shown in <FIG>, the chain saw <NUM> of the present embodiment includes a thumb rest <NUM>, a power switch <NUM>, and an indicator light <NUM> on the upper surface of the front end part <NUM> of the top handle <NUM>.

The thumb rest <NUM>, the power switch <NUM>, and the indicator light <NUM> are arranged on a recessed surface 40a formed on the upper surface of the top handle <NUM>. The recessed surface 40a is slightly recessed with respect to the upper end surface of the gripping part <NUM> (see <FIG>). Further, the recessed surface 40a includes a protruding part 40b protruding rightward with respect to the right side surface of the gripping part <NUM>.

The thumb rest <NUM> is an area on which the pad of the thumb of the right hand is placed when the operator grips the gripping part <NUM> with the right hand. The thumb rest <NUM> is arranged on a longitudinal axis L running through the center in the lateral direction of the gripping part <NUM>.

The power switch <NUM> is a push-button switch to make the motor <NUM> (see <FIG>) drive in an on-state and make the driving of the motor <NUM> stop in in off-state. The power switch <NUM> is formed to have a circular shape in plan view, and slightly protrudes with respect to the recessed surface 40a (see <FIG>). The power switch <NUM> is switched on and off every time the power switch <NUM> is pushed down.

When the power switch <NUM> is pushed in a state where the driving of the motor <NUM> is stopped so as to be in an on-state, the battery <NUM> supplies power to the control board (not shown), to change to a state where the driving of the motor <NUM> is on standby. Then, when the trigger lever 43a is pulled in a state where the lock release lever 43b is being pushed down, the battery <NUM> supplies power to the motor <NUM> through the control board so that the motor <NUM> is driven.

When the power switch <NUM> is pushed in a state where the motor <NUM> is being driven so as to be in an off-state, the power supply to the motor <NUM> is interrupted and the driving of the motor <NUM> is stopped.

The power switch <NUM> is arranged side by side on the right side of the thumb rest <NUM>. The power switch <NUM> is arranged on the protruding part 40b of the recessed surface 40a. Thus, the power switch <NUM> is arranged at a position protruding onto the opposite side (right side) of the side handle <NUM> (left side) with respect to the top handle <NUM>.

The indicator light <NUM> is a light emitting diode (LED) arranged in the thumb rest <NUM>. The indicator light <NUM> indicates the on/off state of the power switch <NUM>. The indicator light <NUM> is turned on when the power switch <NUM> is in an on-state and is turned off when the power switch <NUM> is in an off-state.

When an object to be cut, such as a tree or a plate, is cut with the chain saw <NUM> as shown in <FIG>, the operator grips the gripping part <NUM> of the top handle <NUM> with the right hand, and grips the side handle <NUM> with the left hand to carry the chain saw <NUM>.

When the operator grips the gripping part <NUM> of the top handle <NUM> with the right hand, the lock release lever 43b is pushed down with the palm, and the lock of the trigger lever 43a is released. Further, the operator places the pad of the thumb of the right hand, with which the gripping part <NUM> is gripped on the thumb rest <NUM> in <FIG> so that the operator can stably hold the top handle <NUM>.

Next, the operator shifts the thumb of the right hand to the right to push the power switch <NUM> so as to be in an on-state. Accordingly, the indicator light <NUM> is turned on, and the driving of the motor <NUM> is on standby.

The pad of the thumb of the right hand is then returned to the thumb rest <NUM>, and when the trigger lever 43a is pulled up with the index finger of the right hand, as shown in <FIG>, the motor <NUM> is driven to rotate the saw chain <NUM>. As a result, the object to be cut can be cut with the saw chain <NUM>.

The operator can cut the object to be cut while placing the thumb on the thumb rest <NUM> during operation. In this case, depending on the operation situation, the operator lightly places the thumb on the thumb rest <NUM> and grips the gripping part <NUM> to perform the cutting operation while stably gripping the gripping part <NUM>, or pushes the thumb rest <NUM> with the thumb so as to push the object to be cut to stably perform the cutting operation.

When the operation needs to be stopped, the trigger lever 43a is returned to stop the driving of the motor <NUM>, and then the thumb of the right hand is shifted to the right to push the power switch <NUM> so as to be in an off-state. Further, when the operation needs to be urgently stopped, the power switch <NUM> is pushed with the thumb of the right hand so as to be in an off-state, without the trigger lever 43a returned. Consequently, the driving of the motor <NUM> is stopped.

As shown in <FIG>, in the chain saw <NUM> (electric power work device) as described above, the battery <NUM> in a large shape is detachably attached to the rear end part of the body case <NUM>. Further, the top handle <NUM> extending in the longitudinal direction is formed on the upper part of the body case <NUM>. The thumb rest <NUM>, the power switch <NUM>, and the indicator light <NUM> are arranged on the upper surface of the front end part <NUM> of the top handle <NUM>. The power switch <NUM> is arranged on the right side of the thumb rest <NUM>.

In the chain saw <NUM> according to the present embodiment, when the operator grips the gripping part <NUM>, the operator places the pad of the thumb on the thumb rest <NUM> to stably grip the top handle <NUM>. Further, the motor <NUM> is accommodated in the front part of the body case <NUM> and the battery <NUM> in a large shape is attached to the rear part thereof, to allow the chain saw <NUM> to be well-balanced in weight in the longitudinal direction. Therefore, the handling of the chain saw <NUM> is improved during operation, to improve working efficiency.

In the chain saw <NUM> of the present embodiment, the thumb rest <NUM> is arranged on the longitudinal axis L running through the center in the lateral direction of the gripping part <NUM>. In the configuration, when the operator grips the gripping part <NUM> and places the pad of the thumb on the thumb rest <NUM>, the thumb is extended along the longitudinal axis L, to allow the operator to stably grip the top handle <NUM>.

In the chain saw <NUM> of the present embodiment, the operator can switch on/off the power switch <NUM> with the thumb while gripping the top handle <NUM>. Therefore, after the operator switches off the power switch <NUM> to stop the motor <NUM> while gripping the top handle <NUM> during operation, the operator can switch on the power switch <NUM> while gripping the top handle <NUM> to resume the operation promptly.

In this case, the power switch <NUM> is arranged near the thumb rest <NUM>. Therefore, even if the operator switches off the power switch <NUM> by mistake during operation, the operator can push the power switch <NUM> again while gripping the top handle <NUM> to continue the operation.

As described above, in the chain saw <NUM> according to the present embodiment, the operator can stably grip the top handle <NUM> and can switch on/off the power switch <NUM> while holding the chain saw <NUM> with both hands. Therefore, with the chain saw <NUM> of the present embodiment, the operator can work smoothly, to improve working efficiency.

In the chain saw <NUM> of the present embodiment, the power switch <NUM> is arranged on the side of the thumb rest <NUM>, to have the length in the longitudinal direction of the top handle <NUM> decreased. As a result, the entire chain saw <NUM> is reduced in size.

In the chain saw <NUM> of the present embodiment, the power switch <NUM> is a push-button switch, so that the operator can easily manipulate the power switch <NUM> with only the thumb while gripping the gripping part <NUM>.

Note that the chain saw <NUM> of the present embodiment is configured to include the gripping part <NUM> so as to be gripped with the right hand of the operator, and the power switch <NUM> is arranged on the right side of the thumb rest <NUM>. It is more difficult to shift the thumb of the right hand gripping the gripping part <NUM> toward the right side than toward the left side, to allow for preventing the power switch <NUM> from being manipulated by mistake.

In the chain saw <NUM> of the present embodiment, the thumb rest <NUM> and the power switch <NUM> are arranged on the recessed surface 40a formed on the upper surface of the top handle <NUM>. Therefore, the operator can move the pad of the thumb on the recessed surface 40a to sense the position of the power switch <NUM> (see <FIG>).

Preferably, the power switch <NUM> may protrude slightly upward with respect to the recessed surface 40a. With this configuration, the operator can easily sense the position of the power switch <NUM>, and when switching off the power switch <NUM>, the operator cannot switch off the power switch <NUM> without moving the thumb upward. Therefore, the power switch <NUM> is prevented from being manipulated by mistake.

In the chain saw <NUM> of the present embodiment, the indicator light <NUM> is arranged in the thumb rest <NUM>, to indicate the on/off state of the power switch <NUM>. Therefore, the operator can accurately grasp the state of the power switch <NUM>, to improve safety.

In the chain saw <NUM> of the present embodiment, the battery <NUM> is mounted in the battery attachment part <NUM> such that the longitudinal direction of the battery <NUM> corresponds to the height direction of the body case <NUM>. In the configuration, the center of gravity of the battery <NUM> can be positioned more on the front side even if the battery <NUM> is increased in size in the height direction, as compared with a case where the longitudinal direction of the battery <NUM> is oriented in the lateral direction. Therefore, the handling of the chain saw <NUM> having the battery <NUM> in a large shape is improved during operation, and the chain saw <NUM> is reduced in size.

In the chain saw <NUM> according to the present embodiment, the upper part of the battery <NUM> mounted to the battery attachment part <NUM> protrudes above the rear end part of the top handle <NUM>, and the battery <NUM> is inclined so as to be separated rearward from the gripping part <NUM>. In the configuration, even if the battery <NUM> is elongated in the vertical direction, the operator is not disturbed by the upper part of the battery <NUM> when gripping the gripping part <NUM>. Therefore, the battery <NUM> can be made larger without reducing the operability of the chain saw <NUM>.

In the present embodiment, the chain saw <NUM> applied with the present invention has been described. However, an electric power work device applicable with the present invention is not limited to a chain saw, and the present invention is applicable to various electric power work devices such as a brush cutter, a hedge trimmer, and a blower.

Claim 1:
An electric power work device (<NUM>) comprising:
a body case (<NUM>);
a work tool (<NUM>) protruding forward from a front side with respect to the body case (<NUM>);
a motor (<NUM>) driving the work tool (<NUM>); and
a battery (<NUM>) supplying power to the motor (<NUM>),
wherein the motor (<NUM>) is accommodated in the body case (<NUM>) and the battery (<NUM>) is detachably attached to a rear side with respect to the body case (<NUM>),
a top handle (<NUM>) is extended in a longitudinal direction at an upside with respect to the body case (<NUM>),
the top handle (<NUM>) includes, on an upper surface of a front part thereof, a thumb rest (<NUM>) and a power switch (<NUM>) which drives the motor (<NUM>) in an on-state and stops the motor (<NUM>) in an off-state; and
wherein the top handle (<NUM>) includes a gripping part (<NUM>),
the thumb rest (<NUM>) is an area on which, in use, a pad of the thumb is placed when an operator grips the gripping part (<NUM>),
the thumb rest (<NUM>) is arranged on a longitudinal axis running through a center in a lateral direction of the gripping part (<NUM>),
the thumb rest (<NUM>) and the power switch (<NUM>) are arranged on a recessed surface (40a) formed on an upper surface of the top handle (<NUM>), the thumb rest (<NUM>) being a portion of the recessed surface (40a), characterized in that
the recessed surface (40a) includes a protruding part (40b) protruding rightward with respect to a right side surface of the gripping part (<NUM>), and the power switch (<NUM>) is arranged on the protruding part (40b) of the recessed surface (40a) and further characterized in that the power switch (<NUM>) is arranged on a right side in a lateral direction of the thumb rest (<NUM>).