Patent Description:
A trimming machine, such as a hedge trimmer and a clipper used for trimming or cropping hedges or plants, includes a blade drive gear rotationally driven by a drive source in a body case, a cam (eccentric cam) including upper and lower eccentric disks that are each provided on one face side of the gear, and a pair of upper and lower blades mutually slidably facing and contacting each other, and is configured to perform trimming or cropping by causing the eccentric cam to reciprocate the elongated upper and lower blades in mutually (relatively) opposite directions along the longitudinal direction of the blades, thereby grinding their cutting edges in a comb-like tooth shape against each other (see, for example, Patent Literature <NUM>).

There are some conventional trimming machines in which a main shaft is rotatably and axially supported on a transmission case of a body case (working machine main body) and is driven through a centrifugal clutch by a crank shaft of an internal combustion engine as a drive source so as to reciprocate upper and lower blades (see, for example, Patent Literature <NUM>).

A trimming machine according to the preamble of claim <NUM> is disclosed in patent literature <NUM>.

In a trimming machine adopting the aforementioned clutch mechanism, when the cutting edges are caught in a solid material made of a wide branch, a fence, steel or the like while performing trimming or cropping, causing the blades to be locked, since the clutch mechanism slides to release the rotating force of the engine or the shock (large torque) at the time of locking, the shock at the time of locking or the like is less likely to be directly transmitted to the gear, thereby suppressing damage to the gear.

Meanwhile, in a trimming machine electrically driven by an electric motor (hereinafter simply referred to as a motor in some cases) as a drive source, when locking occurs while performing trimming or cropping without adopting the clutch mechanism, the rotating force of the motor or the shock (large torque) at the time of locking cannot be released by means of the clutch mechanism, which could damage (tooth lacking or the like) the gear due to the direct transmission of the shock at the time of locking or the like.

As a measure to address the foregoing, for example, adoption of the clutch mechanism as in the engine-driven machines may be considered. However, such a measure could cause problems in that heavier load is put on the user due to degraded operability as a result of weight increase, and cost increases.

The present invention has been made in view of the foregoing and provides a trimming machine capable of suppressing damage to a gear when blades are locked, with a simple structure without increasing weight and cost.

To provide solution to the foregoing, the trimming machine according to the present invention basically includes: an electric motor; a blade drive gear rotationally driven by the electric motor; an eccentric cam provided in the gear; and a pair of blades relatively slidably facing and contacting each other, in which the eccentric cam is adapted to reciprocate the pair of blades in relatively opposite directions along a longitudinal direction of the blades, thereby grinding cutting edges against each other, the cutting edges provided in a protruding manner with gaps therebetween in the pair of blades, and a shock absorbing portion is provided between a connecting portion connected to the eccentric cam and the cutting edges in each of the blades, the shock absorbing portion being adapted to be deformed so as to release shock generated when the blades are locked.

In a preferred aspect, the trimming machine may include a connecting rod that connects the eccentric cam and each of the blades, and the shock absorbing portion may be provided between a connecting portion connected to the connecting rod and the cutting edges in each of the blades.

In another preferred aspect, the shock absorbing portion may include a fragile portion.

In yet another preferred aspect, the shock absorbing portion may include a slit portion extending in an orthogonal direction relative to a reciprocating direction of the blades.

In further another preferred aspect, the width in the orthogonal direction of the shock absorbing portion including the slit portion may be wider than the width in the orthogonal direction of each of the blades between the connecting portion and the shock absorbing portion and/or may be wider than the width in the orthogonal direction of each of the blades between the shock absorbing portion and the cutting edges.

In another preferred aspect, the width in the orthogonal direction of the shock absorbing portion including the slit portion may be narrower than the width in the orthogonal direction of the cutting edges provided in a protruding manner in each of the blades.

In yet another preferred aspect, the slit portion may be provided with a fragile portion.

In further another preferred aspect, the fragile portion may include at least one of a notch, a cutout, a recess, or a groove.

In yet another preferred aspect, the slit portion may extend, in the orthogonal direction relative to the reciprocating direction of the blades, from an elongated aperture into which a member that retains the pair of blades reciprocatively in relatively opposite directions along the longitudinal direction of the blades is inserted.

In further another preferred aspect, the slit portion may extend, in the orthogonal direction relative to the reciprocating direction of the blades, from a position different from the elongated aperture into which the member that retains the pair of blades reciprocatively in relatively opposite directions along the longitudinal direction of the blades is inserted.

According to the present invention, since a shock absorbing portion only needs to be provided between the connecting portion and the cutting edges in the blades, the shock absorbing portion being adapted to be deformed so as to release shock or the like generated when the blades are locked, damage to the gear can be suppressed when the blades are locked, with a simple structure without increasing weight and cost.

An embodiment of the present invention will be described in detail below by referring to the drawings, as appropriate. A hedge trimmer, which is one type of a trimming machine, will be described below by way of an example. Further, in the present specification, the blade (cutting edge) side is the front side or the leading end side, the body case side is the rear side or the proximal end side, and the side where a front handle held by an operator projects is the upper side and its opposite side is the lower side. However, up-down, front-back, and left-right directions are used for convenience in explaining the hedge trimmer of the present embodiment and do not limit the configuration or use state of the hedge trimmer.

As shown in <FIG>, a hedge trimmer <NUM> of the present embodiment is a hand-held compact cutting working machine used for trimming or cropping hedges or plants, and is electrically driven by a battery <NUM> mounted thereon. As shown in <FIG>, the hedge trimmer <NUM> includes an electric motor <NUM> as a drive source, a blade assembly <NUM> disposed forward of the electric motor <NUM>, and a body case <NUM> that houses the electric motor <NUM>.

The body case <NUM> is a resin body in a box shape with the upper face inclined relative to the lower face. The upper face of the body case <NUM> is inclined from the rear side toward the front side. That is, the front portion of the body case <NUM> is formed lower than the rear portion. Further, the body case <NUM> is in a substantially triangular shape in a side view.

The upper face of the body case <NUM> is provided with a battery attachment portion <NUM> for attaching the battery <NUM>. The battery attachment portion <NUM> is inclined from the rear portion toward the front portion so as to follow the upper face of the body case <NUM>.

The battery <NUM> is a known battery that houses a secondary battery such as a lithium ion storage battery in its cuboid case extending in the front-back direction. An engagement portion <NUM> that engages with the battery attachment portion <NUM> projects in the rear end portion on the lower face of the battery <NUM> as shown in <FIG> and <FIG>.

For attaching the battery <NUM> to the battery attachment portion <NUM>, while the battery <NUM> is caused to slide from the rear side toward the front side relative to the battery attachment portion <NUM>, the lower portion of the battery <NUM> is fitted to the battery attachment portion <NUM>. Then, when the front end portion of the battery <NUM> reaches a position where it is supported on the front end portion of the battery attachment portion <NUM>, the engagement portion <NUM> of the battery <NUM> engages with the battery attachment portion <NUM>, thereby fixing the battery <NUM> to the battery attachment portion <NUM>.

The upper face of the battery attachment portion <NUM> is provided with a metal connection terminal (not shown). The connection terminal is electrically connected to a control board (not shown) or the electric motor <NUM>. Further, a connection terminal of the battery <NUM> is connected to the connection terminal of the battery attachment portion <NUM>, so as to supply power from the battery <NUM> to the control board or the electric motor <NUM>.

For removing the battery <NUM> from the battery attachment portion <NUM>, a coupling lever <NUM> (<FIG>) provided in the rear end portion of the battery <NUM> is lifted to disengage the engagement portion <NUM> from the battery attachment portion <NUM> so as to allow the battery <NUM> to be slidable rearward relative to the battery attachment portion <NUM>.

As shown in <FIG>, a front handle <NUM> is provided forward of the body case <NUM>. The front handle <NUM> is disposed forward of the battery <NUM> attached to the battery attachment portion <NUM>. The front handle <NUM> is in a gate-like shape as viewed from the front side, and has left and right vertical portions extending downward respectively from the left and right ends of a lateral portion extending in the left-right direction, with the lower ends of both the vertical portions fixed to the front end portion of the body case <NUM>. A front guard <NUM> is provided between the lower ends of the two vertical portions of the front handle <NUM>. The front guard <NUM> is formed so as to cover the blade assembly <NUM> (the proximal end portion thereof) from the upper side.

A rear handle <NUM> is provided rearward of the body case <NUM>. A coupling portion <NUM> coupled to the rear portion of the body case <NUM> and a gripping portion <NUM> having an opening formed therethrough in the left-right direction are formed in the rear handle <NUM>. To hold the hedge trimmer <NUM>, the operator grips the rear handle <NUM> by inserting his/her hand into the opening of the gripping portion <NUM>. As shown in <FIG>, the coupling portion <NUM> of the rear handle <NUM> is coupled rotatably about the axis in the front-back direction relative to the rear face of the body case <NUM>, thereby allowing the rear handle <NUM> in its entirety to be rotatable about the axis in the front-back direction relative to the body case <NUM>.

As shown in <FIG>, an inner periphery portion of the gripping portion <NUM> of the rear handle <NUM> is provided with a trigger lever <NUM> that is an operation means to rotate the electric motor <NUM> and thereby drive the blade assembly <NUM>, while the operator grips the handle. Further, the upper face of the gripping portion <NUM> is provided with a power switch <NUM> as well as an unlocking lever <NUM> for unlocking the trigger lever <NUM>.

It should be noted that it is obvious that the shape of the body case <NUM>, the arrangement or attachment structure of the battery <NUM>, and the like are not limited to those in the illustrated examples.

Further, in the hedge trimmer <NUM> of the present embodiment, power is supplied from the battery <NUM> to the control board or the electric motor <NUM>, but for example, power may be supplied to the control board or the electric motor <NUM> from an external power source via a power cord instead of using the battery <NUM>.

As shown in <FIG>, the blade assembly <NUM> extends linearly forward relative to the electric motor <NUM> and projects forward from the front end portion of the body case <NUM>. The blade assembly <NUM> is a cutting device including an upper blade <NUM> and a lower blade <NUM> that are made of metal and a resin cover <NUM>.

The upper blade <NUM> and the lower blade <NUM> are an elongated plate-shaped edge tool and are overlaid with one above the other. The upper blade <NUM> and the lower blade <NUM> are in an upper and lower pair mutually (relatively) slidably facing and contacting each other. As shown in <FIG>, a plurality of cutting edges <NUM> is formed in the upper blade <NUM> and the lower blade <NUM> so as to protrude with predetermined gaps therebetween in the left-right direction along the longitudinal direction of the blades. The cover <NUM> is a protective member to prevent the contact between the operator's hand and the upper blade <NUM> and the lower blade <NUM>, and covers the upper face of the upper blade <NUM>.

As shown in <FIG>, a required number of elongated apertures (elongated apertures in the longitudinal direction) <NUM> are formed with predetermined gaps therebetween in the upper blade <NUM> and the lower blade <NUM> along the longitudinal direction. The elongated apertures <NUM> each have a length that allows the reciprocating motion of the upper blade <NUM> and the lower blade <NUM>. In addition, square cylindrical spacers <NUM> each having a rectangular insertion round aperture in a plan view are slidably fit-inserted into the elongated apertures <NUM> (elongated apertures overlaid with one above the other) of the upper blade <NUM> and the lower blade <NUM>. Bolts <NUM> as a fastening member are inserted into the insertion round apertures (in some locations in the longitudinal direction, a through-hole provided in the cover <NUM> may be included) of the square cylindrical spacers <NUM> for fastening. In this manner, the upper blade <NUM> and the lower blade <NUM> are securely fastened at predetermined locations along the longitudinal direction while being mutually (relatively) slidably held.

As shown in <FIG> and <FIG>, a connecting portion <NUM> that is connected to a movable plate <NUM>, which will be described later, is formed in each of the rear end portions (the proximal end portions) of the upper blade <NUM> and the lower blade <NUM>. In the present embodiment, the connecting portion <NUM> is formed as a short cylindrical projection (provided in a protruding manner) and is inserted into an opening of a leading end portion of the movable plate <NUM> described later so that the upper blade <NUM> and the lower blade <NUM> are coupled with the movable plate <NUM>. However, the configuration of the connecting portion <NUM>, that is, the connecting configuration between the upper blade <NUM> and the lower blade <NUM> and the movable plate <NUM> is not limited to the example shown in the drawings. For example, a circular opening as the connecting portion may be formed in each of the upper blade <NUM> and the lower blade <NUM> and a cylindrical projection formed in the movable plate <NUM> may be inserted into the openings for coupling.

The rear end portions of the upper blade <NUM> and the lower blade <NUM> are inserted into the body case <NUM> as shown in <FIG> and <FIG>. The rear end portions of the upper blade <NUM> and the lower blade <NUM> are coupled to the electric motor <NUM> via a drive transmission mechanism <NUM>.

The drive transmission mechanism <NUM> includes a blade drive gear <NUM>, upper and lower eccentric cams (hereinafter simply referred to as cams) <NUM>, <NUM> provided in the blade drive gear <NUM>, and upper and lower movable plates (also referred to as connecting rods) <NUM>, <NUM>.

The blade drive gear <NUM> is a disk-like gear having a support shaft <NUM> projecting in the up-down direction from the center portion. The upper end portion and the lower end portion of the support shaft <NUM> are rotationally supported by upper and lower bearings <NUM>, <NUM> provided in the body case <NUM>. That is, the blade drive gear <NUM> rotates about the axis of the support shaft <NUM>.

The upper and lower cams <NUM>, <NUM> formed of eccentric disks project on the upper face and the lower face of the blade drive gear <NUM>, respectively. The upper and lower cams <NUM>, <NUM> are positioned eccentrically to one side and the other side, respectively, relative to the center of rotation (the center of the support shaft <NUM>) of the blade drive gear <NUM>. In the present embodiment, the upper and lower cams <NUM>, <NUM> are integrally formed in the gear <NUM> through shaving.

The cam <NUM> on the upper side is inserted into an opening of a rear end portion of the movable plate <NUM> on the upper side for engagement, and the connecting portion <NUM> in the rear end portion of the upper blade <NUM> is inserted into the opening in the leading end portion of the movable plate <NUM> on the upper side for coupling. The cam <NUM> on the lower side is inserted into the opening of the rear end portion of the movable plate <NUM> on the lower side for engagement, and the connecting portion <NUM> in the rear end portion of the lower blade <NUM> is inserted into the opening in the leading end portion of the movable plate <NUM> on the lower side for coupling.

The drive transmission mechanism <NUM> is configured such that the upper and lower cams <NUM>, <NUM> rotationally move along with the rotation of the blade drive gear <NUM>, so that the upper and lower movable plates <NUM>, <NUM> reciprocate in the front-back direction and the upper blade <NUM> and the lower blade <NUM> reciprocate oppositely to each other in the front-back direction (in other words, reciprocate with predetermined strokes in mutually opposite directions along the longitudinal direction) (see <FIG> and <FIG>). In other words, the configuration is made such that the rotational motion of the electric motor <NUM> is converted into the reciprocating motion of the upper blade <NUM> and the lower blade <NUM> in the front-back direction (longitudinal direction) via the upper and lower movable plates <NUM>, <NUM> of the drive transmission mechanism <NUM>.

The aforementioned blade drive gear <NUM>, cams <NUM>, <NUM>, movable plates <NUM>, <NUM>, and the like are housed in a case <NUM> of the drive transmission mechanism <NUM>. The case <NUM> includes a top plate <NUM> and a bottom plate <NUM>. The top plate <NUM> and the bottom plate <NUM> of the case <NUM> are formed so as to cover a rear end portion of the blade assembly <NUM> as well as the blade drive gear <NUM>, cams <NUM>, <NUM>, movable plates <NUM>, <NUM>, and the like from the upper and lower sides. The blade assembly <NUM> projects forward from a front end portion of the case <NUM>.

It should be noted that the present embodiment adopts a type of method using a connecting rod in which the upper and lower cams <NUM>, <NUM> and the upper blade <NUM> and the lower blade <NUM> (connecting portions <NUM>, <NUM> thereof) are indirectly connected via the upper and lower movable plates <NUM>, <NUM>, but it is obvious that for example, a type of method using an elongated aperture may be adopted, in which elongated apertures (elongated apertures in the left-right direction) as the connecting portions are formed in the rear end portions (proximal end portions) of the upper blade <NUM> and the lower blade <NUM>, and the upper and lower cams <NUM>, <NUM> are inserted into the elongated apertures (connecting portions) so as to cause the upper blade <NUM> and the lower blade <NUM> to reciprocate in the front-back direction, that is, the upper and lower cams <NUM>, <NUM> and the upper blade <NUM> and the lower blade <NUM> (connecting portions thereof) are directly connected.

The electric motor <NUM> is provided above a rear portion of the drive transmission mechanism <NUM>. The electric motor <NUM> includes a stator <NUM>, an outer rotor <NUM>, an output shaft <NUM>, and a base member <NUM>.

The stator <NUM> is provided with a plurality of coils 51a. A lower end portion of the base member <NUM> provided on an inner periphery of the stator <NUM> is fixed to the case <NUM> (top plate <NUM> thereof) of the drive transmission mechanism <NUM>.

The output shaft <NUM> is inserted into a bearing provided on an inner periphery surface of the base member <NUM>. In this manner, the output shaft <NUM> is rotationally supported on the base member <NUM>. A lower end portion of the output shaft <NUM> is provided with an output gear 53a. The output gear 53a meshes with the blade drive gear <NUM> of the drive transmission mechanism <NUM>.

In the outer rotor <NUM>, a cylindrical peripheral wall portion 52a surrounding the outer periphery of the stator <NUM> and each coil 51a, and a top portion 52b closing an upper face opening of the peripheral wall portion 52a are formed. The outer rotor <NUM> of the present embodiment is made of iron, but the material of the outer rotor as a wheel is not limited. A plurality of magnets 52c is attached on an inner periphery surface of the peripheral wall portion 52a.

An upper end portion of the output shaft <NUM> is coupled to the center portion of the top portion 52b of the outer rotor <NUM>. In this manner, the outer rotor <NUM> is rotationally supported on the stator <NUM>, so that the output shaft <NUM> and the outer rotor <NUM> rotate in association with each other. A rotating axis L of the outer rotor <NUM> and the output shaft <NUM> extends in the up-down direction orthogonal to the extending direction (front-back direction) of the blade assembly <NUM>.

The outer rotor <NUM> has a diameter (in the lateral direction) greater than the length in the rotating axis L direction (in the up-down direction). That is, when the outer rotor <NUM> is viewed from the lateral direction (the direction orthogonal to the rotating axis L), it is in a flat shape with the lateral width greater than the height.

The outer rotor <NUM> is rotationally supported on the stator <NUM> and is coupled to the rear end portion of the blade assembly <NUM> via the drive transmission mechanism <NUM>. Further, when power is supplied from the battery <NUM> to each coil 51a of the stator <NUM>, the outer rotor <NUM> and the output shaft <NUM> rotate and the drive force is transmitted to the blade assembly <NUM> via the drive transmission mechanism <NUM>, so that the upper blade <NUM> and the lower blade <NUM> reciprocate oppositely to each other in the front-back direction (see <FIG> and <FIG>). That is, the cams <NUM>, <NUM> of the drive transmission mechanism <NUM> cause the upper and lower pair of elongated upper blade <NUM> and lower blade <NUM> to reciprocate in mutually (relatively) opposite directions along the longitudinal direction of the blades, thereby grinding the cutting edges <NUM> in a comb-like tooth shape, which are provided in the blades, against each other, so as to perform trimming or cropping of hedges or plants.

In the hedge trimmer <NUM> electrically driven by the electric motor <NUM> with the aforementioned configuration as a drive source, when locking occurs while performing trimming or cropping without adopting the clutch mechanism, the rotating force of the motor <NUM> or the shock (large torque) at the time of locking cannot be released by means of the clutch mechanism, which could damage (tooth lacking or the like) the gear <NUM> due to the direct transmission of the shock at the time of locking or the like.

Thus, in the present embodiment, in order to suppress the damage to the gear <NUM> when the blades (upper blade <NUM>, lower blade <NUM>) are locked, a shock absorbing portion <NUM> is provided between the connecting portion <NUM> and the cutting edges <NUM> (specifically, the cutting edges <NUM> positioned on the most proximal end side or the connecting portion <NUM> side) in the blade (upper blade <NUM>, lower blade <NUM>).

It should be noted that the shock absorbing portion <NUM> may be provided in both or one of the upper blade <NUM> and the lower blade <NUM>. The details will be described below by way of an example in which the shock absorbing portion <NUM> is provided in the lower blade <NUM>.

The shock absorbing portion <NUM> is the most fragile portion on the lower blade <NUM> and is adapted to suppress (absorb) the shock at the time of locking or the like that is transmitted to the gear <NUM> via the movable plate <NUM> or the like, by being deformed or broken, when locking occurs. As is clear by referring to <FIG> and <FIG>, in the present embodiment, the shock absorbing portion <NUM> includes a slit portion <NUM> and a fragile portion <NUM>.

The slit portion <NUM> is formed so as to extend in the left-right direction (the orthogonal direction relative to the reciprocating direction). Further, the ends in the left-right direction of the slit portion <NUM> are each formed in substantially circular with the width slightly wider than that of the middle section (wider in the front-back direction). In the present embodiment, the width (Ls) in the left-right direction of the shock absorbing portion <NUM> including the slit portion <NUM> is wider than the width in the left-right direction of the lower blade <NUM>. That is, the width (Ls) in the left-right direction of the shock absorbing portion <NUM> including the slit portion <NUM> is wider than the width (La) in the left-right direction of the lower blade <NUM> between the connecting portion <NUM> and the shock absorbing portion <NUM> and/or the width (Lb) in the left-right direction of the lower blade <NUM> between the shock absorbing portion <NUM> and the cutting edges <NUM>. Furthermore, the width (Ls) in the left-right direction of the shock absorbing portion <NUM> including the slit portion <NUM> is narrower than the width (Lc) in the left-right direction of the cutting edges <NUM> provided in a protruding manner in the left-right direction in the lower blade <NUM>. In other words, the shock absorbing portion <NUM> including the slit portion <NUM> is formed such that it is positioned on the inner side in the left-right direction as compared to the cutting edges <NUM> provided in a protruding manner in the lower blade <NUM> so as not to project to the outer side in the left-right direction as compared to the cutting edges <NUM> provided in a protruding manner in the lower blade <NUM>.

The fragile portion <NUM> includes a notch, a cutout, a recess, a groove, or the like. In the present embodiment, the fragile portion <NUM> is formed at each end in the left-right direction of the slit portion <NUM> (in other words, portions of the slit portion <NUM> that are most distanced from the center of the lower blade <NUM>).

With such a configuration, when locking occurs while performing trimming or cropping, the shock absorbing portion <NUM> is deformed due to the shock at the time of locking or the like. Further, when the shock at the time of locking or the like cannot be absorbed only by deforming the shock absorbing portion <NUM> (slit portion <NUM> thereof), the fragile portion <NUM> (notch or the like) provided in the shock absorbing portion <NUM> is broken. Thus, the shock at the time of locking or the like that is transmitted to the gear <NUM> via the movable plate <NUM> or the like can be suppressed (absorbed) by the shock absorbing portion <NUM> being deformed or broken.

Further, in the present embodiment, in relation to the space for installation, the slit portion <NUM> of the shock absorbing portion <NUM> is formed so as to extend in the left-right direction from the elongated aperture <NUM> into which the aforementioned square cylindrical spacer <NUM> is inserted. However, the slit portion <NUM> of the shock absorbing portion <NUM> may be formed so as to extend in the left-right direction from a position different from the elongated aperture <NUM> into which the aforementioned square cylindrical spacer <NUM> is inserted. For example, in the latter case, supposing that at the time of locking, the tension force in the front-back direction is exerted so as to deform the shock absorbing portion <NUM> (slit portion <NUM> thereof), the elongated aperture <NUM> adjacent to the shock absorbing portion <NUM> (slit portion <NUM> thereof) is deformed to be widened in the left-right direction, thereby obtaining the effect of allowing the upper blade <NUM> and the lower blade <NUM> to be smoothly mutually (relatively) slidable (in other words, the sliding motion of the upper blade <NUM> and the lower blade <NUM> is not obstructed).

Furthermore, in the present embodiment, the shock absorbing portion <NUM> is provided in one location between the connecting portion <NUM> and the cutting edges <NUM> in the blade (upper blade <NUM>, lower blade <NUM>). However, it is obvious that the shock absorbing portions <NUM> may be provided in a plurality of locations between the connecting portion <NUM> and the cutting edges <NUM> in the blade (upper blade <NUM>, lower blade <NUM>). In addition, it is evident that the shape of the shock absorbing portion <NUM> is not limited to those shown in the drawings.

As described above, the hedge trimmer <NUM> of the present embodiment includes the electric motor <NUM>, the blade drive gear <NUM> rotationally driven by the electric motor <NUM>, the eccentric cam <NUM> provided in the gear <NUM>, and the pair of blades relatively slidably facing and contacting each other, in which the eccentric cam <NUM> reciprocates the pair of blades in relatively opposite directions along the longitudinal direction of the blades, thereby grinding the cutting edges <NUM>, which are provided in a protruding manner with gaps therebetween in the pair of blades, against each other. Further, the shock absorbing portion <NUM> is provided between the connecting portion <NUM> connected to the eccentric cam <NUM> ( the connecting portion <NUM> connected to the movable plate that connects the cam and the blade) and the cutting edges <NUM> (exactly, the cutting edges <NUM> positioned on the most proximal end side or the connecting portion <NUM> side) in the blade. In this manner, the shock absorbing portion <NUM> is deformed to enable to release the shock or the like generated when the cutting edges are caught in a solid material made of a wide branch, a fence, steel or the like while performing trimming or cropping, causing the blades to be locked (at the time of locking), so that the damage to the gear <NUM> can be suppressed.

Further, the shock absorbing portion <NUM> includes the fragile portion <NUM> (such as a notch). Thus, even when the shock or the like that is too large to be absorbed by the shock absorbing portion <NUM> is exerted, the fragile portion <NUM> (such as a notch) is broken so that the damage to the gear <NUM> can be suppressed. Furthermore, since the fragile portion <NUM> is provided between the connecting portion and the cutting edges, portions of the cutting edges <NUM> do not break, so that the safety is more secured.

It should be noted that since the blades are parts that are typically exchangeable when worn out, even when they are deformed or broken as described above and are thus exchanged, the exchange is easy and the cost can be kept low as compared to the case of exchange due to the damage to the gear <NUM> or the like (that is, a significant cost advantage is obtained).

Moreover, the shock absorbing portion <NUM> includes the slit portion <NUM> extending in the orthogonal direction (lateral direction) relative to the reciprocating direction (longitudinal direction) of the blades. The width in the orthogonal direction of the shock absorbing portion <NUM> including the slit portion <NUM> is wider than the width in the orthogonal direction of each of the blades between the connecting portion <NUM> and the shock absorbing portion <NUM> and/or the width in the orthogonal direction of each of the blades between the shock absorbing portion <NUM> and the cutting edges <NUM>. In this manner, the maintainability is improved, for example, removal of the shavings adhering between the upper blade <NUM> and the lower blade <NUM> is facilitated by allowing the user to grip the shock absorbing portion <NUM> to forcibly slide the blades.

In addition, the width in the orthogonal direction of the shock absorbing portion <NUM> including the slit portion <NUM> is narrower than the width in the left-right direction of the cutting edges <NUM> that are provided in a protruding manner in the left-right direction. With this, the shock absorbing portion <NUM> is less likely to be caught in branches or the like during operation, so that the operability can be maintained.

As described above, according to the present embodiment, the shock absorbing portion <NUM> only needs to be provided between the connecting portion and the cutting edges in the blade, and thus, the weight and cost do not increase, and the damage to the gear <NUM> when the blades are locked can be suppressed with a simple structure.

The scope of the invention is limited by the appended claims.

Claim 1:
A trimming machine (<NUM>) comprising:
an electric motor (<NUM>);
a blade drive gear (<NUM>) rotationally driven by the electric motor (<NUM>);
an eccentric cam (<NUM>) provided in the gear (<NUM>); and
a pair of blades (<NUM>, <NUM>) relatively slidably facing and contacting each other,
wherein:
the eccentric cam (<NUM>) is adapted to reciprocate the pair of blades (<NUM>, <NUM>) in relatively opposite directions along a longitudinal direction of the blades (<NUM>, <NUM>), thereby grinding cutting edges (<NUM>) against each other, the cutting edges (<NUM>) provided in a protruding manner with gaps therebetween in the pair of blades (<NUM>, <NUM>), characterized in that
a shock absorbing portion (<NUM>) is provided between a connecting portion (<NUM>) connected to the eccentric cam (<NUM>) and the cutting edges (<NUM>) in each of the blades (<NUM>, <NUM>), the shock absorbing portion (<NUM>) being adapted to be deformed so as to release shock generated when the blades (<NUM>, <NUM>) are locked.