Patent Description:
As a handheld working machine for cutting or clipping branches and leaves, there has been generally known a hedge trimmer equipped with a reciprocating blade apparatus having reciprocating blades, like a hair clipper. Meanwhile, as a handheld working machine for cutting grass on the ground, there has been generally known a brush cutter equipped with rotary blades or nylon cutters.

The handheld working machine for cutting branches and leaves is required to produce little scattering substances during the work, in order to ensure the safety of the worker and the surrounding of the worker, or to prevent the damage of other people's properties near the working site. The amount of scattering substances produced by the reciprocating blades during the work is less than those of the rotary blade and the nylon cutters which rotate at a high speed. With this advantage of the reciprocating blades, a working machine for cutting grass on the ground has been proposed, for example, in <CIT> (hereinafter <CIT>), which includes a reciprocating blade apparatus mounted to the top end of a handheld operating rod.

This reciprocating blade apparatus mounted to the top end of the operating rod includes blades extending in the direction intersecting the longitudinal direction of the operating rod. A drive source such as an engine and a motor is provided at the base end of the operating rod, and a drive force is transmitted to a power train in a transmission case of the reciprocating blade apparatus via a drive shaft provided in the operating rod. The power train in the transmission case converts the rotation of the drive shaft to reciprocating motion to operate the reciprocating blades coupled to the power train.

The reciprocating blade apparatus disclosed in <CIT>, or provided for the hedge trimmer needs the maintenance of the blades to repeatedly operate with good sharpness. In particular, if the blades are left dirty due to, for example, the adhesion of resin, the blades get rusty or deteriorate, or the distance between the upper and lower blades increases, and consequently become blunt. Accordingly, in order to maintain the performance of the reciprocating blade apparatus, it is necessary to clean the blades after the work.

In this case, although <CIT> approaches to improve the efficiency of the maintenance of the blades to be replaced, it is necessary to take apart a part of the apparatus to detach the blades, and therefore it takes a lot of work and time for the maintenance of the blades. In addition, <CIT> has a problem that when the blades are attempted to be cleaned without taking apart the apparatus, the water enters a transmission case, and therefore a power train is deteriorated.

Moreover, <CIT> has a different problem that one reciprocating blade apparatus can provide only one cutting width, and therefore it is not possible to select the appropriate cutting width depending on whether the work area is small or large. In order to use the blades with the appropriate cutting width depending on whether the work area is small or large, a plurality of blades and their accessory parts need to be prepared and replaced accordingly. However, <CIT> has to take apart the apparatus to replace the blades and their accessory parts, and therefore it takes a lot of work and time for the replacement. Meanwhile, when the replacement is requested to a dealer and so forth, money should be paid for the replacement, and if the user needs to purchase individual apparatuses for various cutting widths, the cost is increased.

<CIT> discloses a reciprocating blade apparatus with reciprocating blades. The reciprocating blades are coupled with reciprocating members, which are located in the same plane as the reciprocating blades, to a transmission case. For maintaining or replacing the reciprocating blades, blade support members have to be removed first followed by separating the reciprocating blades from the reciprocating members and removal of the reciprocating blades from the apparatus.

<CIT> describes a reciprocating blade apparatus, which basically resembles the one of above-mentioned <CIT>. For maintenance or repair of the reciprocating blades, blade support members in the form of bolts and nuts have to be removed first.

To solve the above-described problem, it is desirable to provide a reciprocating blade apparatus capable of improving the efficiency of the maintenance of the blades, more specifically, capable of performing brush cutting with various cutting widths with reduced cost and ease of use.

An aspect of the present invention provides a reciprocating blade apparatus including: a pair of reciprocating blades stacked on one another in a thickness direction, each of which includes a base as a flat plate extending in a longitudinal direction, and a plurality of teeth protruding in a direction intersecting the longitudinal direction; a transmission case including a reciprocating member having a joint detachably coupled to the base, the reciprocating member being reciprocably supported in the longitudinal direction; and a blade support member attached to the transmission case and configured to sandwich bases of the pair of reciprocating blades therebetween to allow the pair of reciprocating blades to move in the longitudinal direction, wherein the blade support member, while supporting the pair of reciprocating blades, is detachably attached to the transmission case.

According to the present invention, it is possible to easily detach the blade support member, while supporting the reciprocating blades, from the transmission case to maintain the reciprocating blades, after the reciprocating blade apparatus is used. By this means, it is possible to clean the reciprocating blades separated from the transmission case, and to reduce the workload and the time for the maintenance of the reciprocating blades.

Moreover, when the length of the blades needs to be changed to change the cutting width, it is possible to easily attach a unit of reciprocating blades having a different length and a blade support member to the transmission case. Therefore, it is possible to perform brush cutting with various cutting widths, while reducing the cost and making it easy for the user to use of the reciprocating blade apparatus.

The same reference numbers in the different drawings indicate the same functional parts, and therefore repeated description for each of the drawings is omitted.

As illustrated in <FIG> and <FIG>, a reciprocating blade apparatus <NUM> includes a pair of reciprocating blades <NUM> (hereinafter referred to as "blade member"), a transmission case <NUM>, and a blade support member <NUM>. The reciprocating blade apparatus <NUM> is configured to cut and mow plants and so forth by sliding and reciprocating the blade member <NUM> relative to one another.

The blade member <NUM> includes two blades 2A and 2B made of metal plates which are stacked in the thickness direction (Z direction in the drawings). Each of the blades 2A and 2B of the blade member <NUM> includes a base <NUM> as a flat plate extending in the longitudinal direction (X direction in the drawings) and a plurality of teeth <NUM> protruding in the direction (Y direction in the drawings) intersecting the longitudinal direction.

The base <NUM> of each of the blades 2A and 2B is supported by the blade support member <NUM>, and includes a plurality of long holes 20A formed along the longitudinal direction (X direction in the drawings) of the blade member <NUM>. Adjustment screws described later as fastening members penetrate the long holes 20A.

The teeth <NUM> may be provided in both sides of each of the blades 2A and 2B in Y direction as illustrated, or provided in one side. These teeth <NUM> are like comblike blades of a hair clipper. The two blades 2A and 2B slide relative to one another in the longitudinal direction to cut the plants between the teeth <NUM> of the blades 2A and 2B.

The transmission case 3A includes a power train to reciprocate the blade member <NUM>. The power train is configured to convert the rotation of a drive shaft (not illustrated) to reciprocating motion, and includes reciprocating members <NUM> (30A and 30B) such as connecting rods which are reciprocably supported in the longitudinal direction (X direction in the drawings) of the blade member <NUM>, and a cam <NUM>.

The reciprocating members <NUM> (30A and 30B) include joints 30t to connect to the bases <NUM> of the blades 2A and 2B, respectively. Each of the joints 30t includes a convex portion protruding in the direction (Y direction in the drawings) orthogonal to the longitudinal direction of the blade member <NUM>. Meanwhile, a concave portion 20B is formed in the base <NUM> to engage with the convex portion of the joint 30t.

As illustrated in <FIG>, each of the reciprocating members 30A and 30B includes a fitting hole <NUM> in which the cam <NUM> is fitted, and guide holes 30n in which guide pieces 32A of the support members <NUM> are fitted to support the reciprocating members <NUM> by the transmission case <NUM>. The guide holes 30n are provided on the right and left sides of the fitting hole <NUM> along X direction in <FIG>.

The blade support member <NUM> is attached to the transmission case <NUM>, and sandwiches the bases <NUM> of the pair of blades 2A and 2B therebetween to allow the blade member <NUM> to move in the longitudinal direction (X direction in the drawings). As illustrated in <FIG>, the blade support member <NUM> includes a pair of support plates (upper support plate 4A and lower support plate 4B) extending in the longitudinal direction (X direction) of the blade member <NUM>.

The upper support plate 4A and the lower support plate 4B of the blade support member <NUM> are fastened via spacers <NUM> to make a space to accommodate the blades member <NUM>. The upper support plate 4A and the lower support plate 4B are individually attached to the transmission case <NUM> while keeping the space. The blade member <NUM> is accommodated in the space and detachably attached to the blade support member <NUM>.

Hereinafter, the configuration where the blade member <NUM> is fastened and supported by the blade support member <NUM> will be described in detail with reference to <FIG>. First, attachment screws <NUM> are screwed into screw holes 41A of the upper support plate 4A via holes 3A of the transmission case <NUM> to independently attach the upper support plate 4A of the blade support member <NUM> to the transmission case <NUM>. Meanwhile, the upper support plate 4A and the lower support plate 4B are fastened by fastening screws <NUM> at fastening points 42A without interfering with the blade member <NUM>. The fastening screws <NUM> penetrate the holes of the lower support plate 4B and the spacers <NUM>, and are screwed into the fastening points 42A of the upper support plate 4A. By this means, the upper support plate 4A and the lower support plate 4B are fastened while keeping the space for the thickness of the spacers <NUM>, and attached to the transmission case <NUM>.

The pair of blades 2A and 2B sandwiched between the upper support plate 4A and the lower support plate 4B is reciprocably supported by the blade support member <NUM> with the adjustment screws <NUM> (43A, 43B, 43C and 43D) at points different from the fastening points 42A. Here, the two adjustment screws 43A and 43D of the four adjustment screws <NUM> are inserted into washers <NUM> and screwed into screw holes <NUM> of the upper support plate 4A via the long holes 20A of the blade member <NUM>, and fixed by fixing nuts <NUM>. In addition, the other two adjustment screws 43B and 43C are inserted into the holes of the lower support plate 4B, and screwed into the screw holes <NUM> of the upper support plate 4A via the long holes 20A of the blade member <NUM>, and fixed by the fixing nuts <NUM>.

In this case, as illustrated in <FIG>, the distance between the washer <NUM> and the upper support plate 4A is adjusted by the adjustment screws 43A and 43D, and therefore it is possible to adjust the distance between the two blades 2A and 2B sandwiched between the washer <NUM> and the upper support plate 4A. In addition, as illustrated in <FIG>, the distance between the upper support plate 4A and the lower support plate 4B is adjusted by the adjustment screws 43B and 43D, and therefore it is possible to adjust the distance between the two blades 2A and 2B sandwiched between the upper support plate 4A and the lower support plate 4B.

The blade member <NUM> is supported by the upper support plate 4A with the adjustment screws 43A to 43D at the positions different from those of the screw holes 41A in which the attachment screws <NUM> are inserted to attach the upper support plate 4A to the transmission case <NUM>. By this means, it is possible to detach the blade member <NUM> simply by removing the adjustment screws <NUM> while the blade support member <NUM> remains attached to the transmission case <NUM>.

Although there are the spacers <NUM> between the upper support plate 4A and the lower support plate 4B, the adjustment screws 43B and 43C are provided at positions different from the fastening points 42A at which the upper support plate 4A and the lower support plate 4B are fastened via the spacers <NUM>. Therefore, it is possible to adjust the distance between the upper support plate 4A and the lower support plate 4B by fastening the adjustment screws 43B and 43C to elastically deform the upper support plate 4A and the lower support plate 4B.

The adjustment of the distance between the two blades 2A and 2B is important to maintain the sharpness of the blade member <NUM>. The ware of the bases <NUM> and the upper and lower support plates 4A and 4B as well as the teeth <NUM> due to repeated use increases the distance between the blades 2A and 2B, and therefore loses the sharpness. To recover the sharpness, maintenance needs to adequately adjust the distance between the blades 2A and 2B by the adjustment screws <NUM>.

As illustrated in <FIG>, the blade support member <NUM>, while supporting the blade member <NUM>, is detachably attached to the transmission case <NUM>. The blade support member <NUM> can be detached from the transmission case <NUM> simply by removing the attachment screws <NUM>. By this means, the blade member <NUM> and the blade support member <NUM> which are unitized with the fastening screws <NUM> and the adjustment screws <NUM> can be detached from the transmission case <NUM>. Hereinafter, the unitized blade member <NUM> and blade support member <NUM> may be referred to as "blade assembly 2U.

In this case, the attachment screws <NUM> and the adjustment screws <NUM> do not interfere with each other, and therefore it is possible to adjust the distance between the blades 2A and 2B with the adjustment screws <NUM> while the blade assembly 2U is detached from the transmission case <NUM> by removing the attachment screws <NUM>. In addition, after the maintenance such as cleaning of the blade assembly 2U detached from the transmission case <NUM>, it is possible to attach the blade assembly 2U to the transmission case <NUM> without changing the adjustment state of the adjustment screw <NUM>.

Then, as illustrated in <FIG>, a blade assembly 2U' including the blade member <NUM> having a different length and the blade support member <NUM> is prepared for the brush cutting with a different cutting width, and replaced with the blade assembly 2U and attached to the transmission case <NUM>. The blade assembly 2U' includes screw holes 41A that allow the blade assembly 2U' to be attached to the transmission case <NUM> with the attachment screws <NUM>. By this means, it is possible to easily replace the blade assembly 2U with the blade assembly 2U' having a different cutting width by removing and inserting the attachment screws <NUM>.

If the blade member <NUM> is displaced after the blade assembly 2U is detached from the transmission case <NUM>, the joints 30t of the reciprocating members 30A and 30B cannot be aligned with the concave portions 20B of the blades 2A and 2B, respectively. Therefore, it is not possible to smoothly engage the joints 30t with the concave portions 20B when the blade assembly 2U is attached to the transmission case <NUM>. To solve this problem, the blade support member <NUM> includes a holding member to hold the position of the blade member <NUM> supported by the blade support member <NUM> when the blade support member <NUM> is detached from the transmission case <NUM>.

To be more specific, when the attachment screws <NUM> are removed from the holes 3A of the transmission case <NUM>, these attachment screws <NUM> are screwed into screw holes 41B of the upper support plate 4A of the blade support member <NUM> to fix the blade member <NUM> to the upper support plate 4A of the blade support member <NUM>. As these holding members, some different screws screwed into the screw holes 41B to fix the blade member <NUM> to the blade support member <NUM> may be prepared. However, when the attachment screws <NUM> are used as the holding members, it is possible to eliminate the disadvantage that the removed attachment screws <NUM> are lost.

When the blade assembly 2U is detached from the transmission case <NUM>, the joint 30t of the reciprocating member 30A engaged with the concave portion 20B of the blade 2A overlaps the joint 30t of the reciprocating member 30B engaged with the concave portion 20B of the blade 2B. By this means, it makes it easy not only to detach the blade assembly 2U from the transmission case <NUM> but also to attach the blade assembly 2U to the transmission case <NUM>. However, when the blade member <NUM> is stopped while the blades 2A and 2B reciprocate, the concave portion 20B of the blade 2A and the concave portion 20B of the blade 2B usually are not aligned with one another, and therefore the joints 30t are not aligned with one another.

Therefore, alignment holes <NUM> of the upper support plate 4A, alignment holes <NUM> of the blade 2A, alignment holes <NUM> of the blade 2B, and alignment holes <NUM> of the lower support plate 4B are provided to align the blades 2A and 2B with one another when the blade member <NUM> is stopped. After the blade member <NUM> is stopped, the blades 2A and 2B can be aligned with one another by inserting a tool such as a flat-blade screwdriver into the alignment holes <NUM> to <NUM>, it is possible to align the concave portions 20B of the blades 2A and 2B with one another before the blade assembly 2U is detached from the transmission case <NUM>. By this means, it is possible to overlap the joints 30t engaged with the concave portions 20B with one other.

While this overlap is maintained, the attachment screws <NUM> as the holding members are screwed into the screw holes 41B, and then inserted into through-holes <NUM> of the blades 2A and 2B. By this means, it is possible to maintain the alignment of the concave portions 2B of the blades 2A and 2B. In this way, the blade member <NUM> is held after the alignment of the blades 2A and 2B. By this means, it makes it easy to detach and attach the blade assembly 2U from and to the transmission case <NUM>.

As described above, the blade member <NUM> is held by the blade support member <NUM>. By this means, it is possible to readily and smoothly engage the concave portions 20B with the joints 30t of the reciprocating member <NUM> to attach the blade assembly 2U to the transmission case <NUM> after the maintenance such as cleaning of the blade assembly 2U detached from the transmission case <NUM>.

The reciprocating blade apparatus <NUM> allows the maintenance of the blades member <NUM> after being used, by easily detaching the blade support member <NUM>, while it supports the blade member <NUM>, from the transmission case <NUM>. By this means, it is possible to clean the blade member <NUM> separated from the transmission case <NUM> while the water does not enter the transmission case <NUM>. In addition, it is possible to detach and attach the blade assembly 2U simply by inserting and removing the attachment screws <NUM>, and therefore to reduce the workload and the time for the maintenance and the replacement of the blade member <NUM>.

Moreover, in order to change the length of the blade member <NUM> to perform brush cutting with a different cutting width, a plurality of blade assemblies 2U including the blade members <NUM> having different lengths are prepared to allow the user to easily replace the blade assembly 2U. Therefore, it is possible to perform brush cutting with various cutting widths, while reducing the cost and making it easy for the user to use of the reciprocating blade apparatus.

<FIG> illustrates an example of handheld working machine including the reciprocating blade apparatus <NUM>. As illustrated in <FIG>, a handheld working machine <NUM> includes an operating rod <NUM>, and the top end of the operating rod <NUM> is mounted to an operating rod mount <NUM> of the transmission case <NUM>. The operating rod mount <NUM> is mounted to the transmission case <NUM> via an angle adjustment mechanism 33A. The angle adjustment mechanism 33A can adjust the rising angle of the operating rod <NUM> from the working surface of the blade member <NUM>.

A drive shaft (not illustrated) configured to transmit a drive force to the power train is provided in the operating rod <NUM>. In addition, a drive unit <NUM> configured to drive the drive shaft is provided at the base end of the operating rod <NUM>, and an operating handle <NUM> is provided in the base end side of the operating rod <NUM>. The operating handle <NUM> includes a grip 13A above the operating rod <NUM>.

The drive unit <NUM> is configured to drive the reciprocating blade apparatus <NUM> via the drive shaft in the operating rod <NUM>, and includes a housing <NUM> to accommodate a motor disposed approximately coaxially with the operating rod <NUM>. A rear handle 14A including an operating switch 14B configured to turn on and off the reciprocating blade apparatus <NUM> is provided in the housing <NUM>. A buttery unit <NUM> configured to supply electric power to the motor in the housing <NUM> is externally attached to the housing <NUM>.

This handheld working machine <NUM> is an electrically-operated brush cutter equipped with the reciprocating blade apparatus <NUM>. The longitudinal direction of the blade member <NUM> intersects the longitudinal direction of the operating rod <NUM>, and therefore the reciprocating blade apparatus <NUM> is provided at the top end of the operating rod <NUM> to form a T-shape. This handheld working machine <NUM> performs brush cutting by driving the reciprocating blade apparatus <NUM> to move the reciprocating blade apparatus <NUM> along the ground while the worker holds the operating handle <NUM> and the rear handle 14A of the housing <NUM> by the hands to keep a predetermined rising angle of the operating rod <NUM> from the ground.

With this handheld working machine <NUM>, the width of the blade member <NUM> of the reciprocating blade apparatus <NUM> is the effective width, and therefore the worker simply pushes the operating rod <NUM> without shaking the operating rod <NUM> from side to side, and consequently it is possible to do the brush cutting with the effective width. Therefore, it is possible to perform the brush cutting by speedily moving the reciprocating blade apparatus <NUM> forward, and consequently to improve the efficiency of the brush cutting. Moreover, the reciprocating blades are used, and therefore it is possible to reduce the scattering substances during the brush cutting. By this means, it is possible to ensure the safety of the worker and the surrounding of the worker, and prevent the damage of other people's properties near the working site during the brush cutting.

Moreover, with the handheld working machine <NUM>, it is possible to reduce the workload and the working time to attach, detach and replace the blade assembly <NUM>, and consequently to improve the efficiency of the maintenance for repeated works.

Claim 1:
A reciprocating blade apparatus (<NUM>) comprising:
a pair of reciprocating blades (<NUM>) stacked on one another in a thickness direction, each of the pair of reciprocating blades (<NUM>) including:
a base (<NUM>) as a flat plate extending in a longitudinal direction; and
a plurality of teeth (<NUM>) protruding in a direction intersecting the longitudinal direction;
a transmission case (<NUM>) including a reciprocating member (<NUM>) having a joint (30t) detachably coupled to the base (<NUM>), the reciprocating member (<NUM>) being reciprocably supported in the longitudinal direction; and
a blade support member (<NUM>) attached to the transmission case (<NUM>) and configured to sandwich bases (<NUM>) of the pair of reciprocating blades (<NUM>) therebetween to allow the pair of reciprocating blades (<NUM>) to move in the longitudinal direction,
characterized in that the blade support member (<NUM>), while supporting the pair of reciprocating blades (<NUM>), is detachably attached to the transmission case (<NUM>).