Portable power working machine

Abstract

The invention is directed to a portable power working machine in which a casing has a side surface in which a suction port is provided. A block prevention guard is attached to the side surface of the casing. The block prevention guard comprises a top surface opening formed in the block prevention guard to at least partially overlap the suction port. The block prevention guard further comprises a plurality of legs standing from the side surface of the casing to maintain the top surface opening at a distance from the side surface. In addition to the top surface surface, an air flow window is formed between two adjacent legs in the circumferential direction of the top surface opening.

Claims

1. A portable power working machine comprising: a casing having a side surface, the casing including inside thereof an air blower and a driving power source for rotationally driving a fan of the air blower, the fan having a rotational axis; a suction port provided in the side surface for intake air; a block prevention guard provided in the side surface of the casing to at least partially overlap the suction port, the block prevention guard comprising a top surface opening consisting of a plurality of first apertures shaped and arranged in a first predetermined geometric pattern, the block prevention guard further comprising a plurality of legs standing from the side surface of the casing to maintain the top surface opening at a distance from the side surface, wherein separately from the top surface opening, the plurality of legs form, between two adjacent legs, an air flow window extending in a circumferential direction of the top surface opening, and an opening area of each of the air flow windows is larger than an average opening area of the plurality of first apertures; and a safety guard attached to the side surface of the casing to overlap the suction port, the safety guard having a main opening consisting of a plurality of second apertures shaped and arranged in a second predetermined geometric pattern, wherein an average opening area of the first apertures is larger than an average opening area of the second apertures, and the first predetermined geometric pattern of the block prevention guard comprises a plurality of first main ribs extending across the top surface opening of the block prevention guard, and the second predetermined geometric pattern of the safety guard comprises a plurality of second main ribs extending across the main opening of the safety guard, the plurality of first and second and main ribs being provided in a same number and arranged in exact overlap with each other when viewed along the rotational axis.

2. The portable power working machine according to claim 1, wherein a sum of the total opening area of the plurality of first apertures in the top surface opening and the air flow windows is larger than a total opening area of the plurality of second apertures of the safety guard.

3. The portable power working machine according to claim 1, wherein each of the suction port and the top surface opening has a circular shape, and centers of the suction port and the top surface opening are aligned with the rotational axis of the fan.

4. The portable power working machine according to claim 1, wherein the first and second predetermined geometric patterns partially overlap with each other.

5. The portable power working machine according to claim 1, wherein the average opening area of the plurality of first apertures of the block prevention guard is three times or more larger than the average opening area of the plurality of second apertures of the safety guard.

6. The portable power working machine according to claim 2, wherein the sum of the total opening area of the plurality of first apertures and the air flow windows is twice or more larger than the total opening area of the plurality of second apertures of the safety guard.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an overall perspective view of an embodiment of a portable power working machine according to the present invention seen obliquely from above and a left rear side.

(2) FIG. 2 is an enlarged exploded perspective view of a main portion of the portable power working machine shown in FIG. 1.

(3) FIG. 3 is an enlarged perspective view of the main portion of the portable power working machine shown in FIG. 1.

(4) FIG. 4 is an enlarged left side view of the main portion of the portable power working machine shown in FIG. 1.

(5) FIG. 5A is an enlarged left side view showing a suction port and a safety guard of the portable power working machine shown in FIG. 1 in a state in which a block prevention guard is removed and FIG. 5B is an enlarged left side view showing a top surface opening and the periphery of a top surface portion of the block prevention guard of the portable power working machine shown in FIG. 1.

(6) FIGS. 6A and 6B show the main portion of the portable power working machine shown in FIG. 1; FIG. 6A is an enlarged exploded plan view, and FIG. 6B is an enlarged plan view.

(7) FIGS. 7A and 7B show the main portion of the portable power working machine shown in FIG. 1; FIG. 7A is an enlarged exploded rear view, and FIG. 7B is an enlarged rear view.

(8) FIGS. 8A and 8B show a main portion of a hand-held air blowing cleaner, as a conventional example, that is one type of the portable power working machine; FIG. 8A is a perspective view seen obliquely from above and a left front side, and FIG. 8B is a rear view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) Hereafter, an embodiment of the present invention will be described referring to the drawings.

(10) FIG. 1 is an overall perspective view of an embodiment of a portable power working machine according to the present invention seen obliquely from above and a left rear side, and FIGS. 2, 3, and 4 are an enlarged exploded perspective view, an enlarged perspective view, and an enlarged left side view of a main portion of the portable power working machine according to the present invention, respectively. It should be noted that in each of the drawings, parts that correspond to those of the aforementioned air blowing cleaner 2 shown as a conventional example in FIGS. 8A and 8B are each denoted with the same symbols as those for the corresponding parts of the aforementioned air blowing cleaner 2.

(11) Further, in the present specification, a side on which a handle is provided is the upper side and a side to which an air blowing pipe is connected is the front side (see the directional arrows in FIG. 1).

(12) Similarly to the hand-held air blowing cleaner 2 shown as the conventional example in FIGS. 8A and 8B, a portable power working machine 1 of the present embodiment is configured such that a handle 12 provided on a body portion 10 made of a synthetic resin is held, for example, with a right hand for cleaning work; a centrifugal air blower 15 with a built-in fan is disposed on the left side (on the operator side when the machine is operated) of the body portion 10; and an engine 50 (small air-cooled two-stroke gasoline engine) that is a driving power source, a fuel tank 54, and the like are disposed on the right side of the body portion 10.

(13) A fan case (volute case) 20 of the air blower 15 has a two-part structure that includes a right side case portion 22 provided on the body portion 10 and a left side case portion 21 securely screwed, with a bolt or the like, to the right side case portion 22, and an air blowing pipe 55 is connected to a discharge port provided on the upper front portion of the fan case 20. Stands 14 for holding the working machine 1 in an upright posture are provided on the lower portion of the body portion 10.

(14) As can be clearly seen with reference to FIG. 5A in addition to FIGS. 1 to 4, a suction port 25 with a circular opening for inhaling air is provided in the vicinity of the center of the one side surface portion (left side surface portion) 20L of the fan case 20 of the air blower 15 such that its center is positioned on the rotational axis O of the fan, and the suction port 25 is provided with a safety guard 30 having a lattice 33 with a predetermined geometric pattern.

(15) Unlike the safety guard 60 in a basket shape in the conventional example, the safety guard 30 of this example has only the lattice 33 that is formed on a flat plane or a slightly curved plane with a single plane (in the suction port 25), and the safety guard 30 (lattice 33) is integrally formed with, for example, the fan case 20 (the left side case portion 21 thereof). The lattice 33 portion has a predetermined number of arc ribs including the three longest main arc ribs 33a, 33b, and 33c, by which the lattice 33 portion is partitioned into three regions 33A, 33B, and 33C in the same shape and size that have a predetermined number of relatively small, substantially rectangular apertures (see FIG. 5A).

(16) Meanwhile, a block prevention guard 40 is attached to the left side surface portion 20L of the fan case 20 for preventing the clothing from being sucked to the safety guard 30 to secure a required area for the air blow. This block prevention guard 40 has a top surface portion 41 provided with a top surface opening 45 with a diameter substantially equal to that of the suction port 25 and three leg portions 42A, 42B, and 42C for allowing the top surface opening 45 of the top surface portion 41 to face the suction port 25 with a predetermined distance therebetween. The top surface opening 45 is positioned such that its center is positioned on the rotational axis O of the fan as with the suction port 25, and the top surface opening 45 is provided with a lattice 43 with a predetermined geometric pattern (the detail will be described later).

(17) It should be noted that in this example, the top surface opening 45 of the top surface portion 41 has the diameter substantially equal to that of the suction port 25 and is provided so as to entirely face the suction port 25, but the top surface opening 45 may be provided so as to partially cover the suction port 25 (for example, a portion where the force of sucking the clothing is strong).

(18) The three leg portions 42A, 42B, and 42C are formed substantially equidistantly from one another, each of which has a cross section in an L or chevron shape. In addition, peripheral surface openings 44A, 44B, and 44C, each of which is relatively large, has a substantially mountain-like shape, and is wider than each of the leg portions 42A, 42B, and 42C, are formed between the leg portions 42A and 42B, between the leg portions 42B and 42C, and between the leg portions 42C and 42A, respectively.

(19) Further, of the three leg portions 42A, 42B, and 42C, the leg portion 42A positioned on the left side as seen in the left side view is provided with a latching claw 46 at the bottom thereof, and the latching claw 46 is adapted to be inserted into and locked to a locking portion (not shown) provided on the fan case 20. Of the three leg portions 42A, 42B, and 42C, the leg portions 42B and 42C positioned on the upper right and lower right, respectively, as seen in the left side view, are each provided with a latch window 47 to which a locking claw 27 that projects from the fan case 20 is fitted and locked.

(20) Furthermore, the lattice 43 portion provided in the top surface opening 45 has a predetermined number of arc ribs including the three longest main arc ribs 43a, 43b, and 43c (which are slightly wider than the main arc ribs 33a, 33b, and 33c that form the lattice 33 of the safety guard 30), by which the lattice 43 portion is partitioned into three regions 43A, 43B, and 43C in the same shape and size that have a predetermined number of relatively large, substantially triangular apertures, and the areas of the three regions 43A, 43B, and 43C are substantially equal to those of the three regions 33A, 33B, and 33C of the safety guard 30, respectively. Moreover, the three longest main arc ribs 43a, 43b, and 43c of the lattice 43 portion provided in the top surface opening 45 are disposed so as to overlap the three longest main arc ribs 33a, 33b, and 33c of the lattice 33 portion of the safety guard 30, respectively, as seen in the left side view. Accordingly, the three regions 43A, 43B, and 43C are adapted to face directly the three regions 33A, 33B, and 33C of the safety guard 30, respectively.

(21) Further, the number of arc ribs that form the lattice 43 of the top surface opening 45 of the block prevention guard 40 is set to be smaller than that of the arc ribs that form the lattice 33 of the safety guard 30 (the suction port 25), and each of the intervals between the arc ribs that form the lattice 43 of the top surface opening 45 of the block prevention guard 40 is set to be larger than each of the intervals between the arc ribs that form the lattice 33 of the safety guard 30 (the suction port 25), and further, the average opening area of the apertures (in a substantially triangular shape) of the lattice 43 provided in the top surface opening 45 is set to be far larger than that of the apertures (in a substantially rectangular shape) of the lattice 33 of the safety guard 30.

(22) In this example, the opening area of the lattice 33 of the safety guard 30 is approximately 7,900 mm.sup.2 and the average opening area of the apertures of the lattice 33 of the safety guard 30 is approximately 150 mm.sup.2, while the opening area of the lattice 43 of the top surface opening 45 of the block prevention guard 40 is approximately 7,400 mm.sup.2 and the average opening area of the apertures of the lattice 43 of the top surface opening 45 of the block prevention guard 40 is approximately 460 mm.sup.2. Further, the opening areas of the peripheral surface openings 44A, 44B, and 44C of the block prevention guard 40 are approximately 6,600 mm.sup.2, approximately 2,300 mm.sup.2, and approximately 4,700 mm.sup.2, respectively, and the total opening area of the block prevention guard 40 (the area obtained by adding the opening area of the lattice 43 of the top surface opening 45 to the opening areas of the peripheral surface openings 44A, 44B, and 44C) is approximately 21,000 mm.sup.2. That is, the average opening area of the apertures of the lattice 43 provided in the top surface opening 45 of the block prevention guard 40 is set to be three times or more that of the apertures of the lattice 33 of the safety guard 30, and the total opening area of the block prevention guard 40 is set to be twice or more the opening area of the lattice of the safety guard 30 (the total opening area of the safety guard 30).

(23) In the working machine 1 of the present embodiment configured in the aforementioned manner, when the fan of the air blower 15 is rotationally driven by the engine 50, the external air passes through the apertures of the lattice 43 of the top surface opening 45 and the peripheral surface openings 44A, 44B, and 44C of the block prevention guard 40 and further through the apertures of the lattice 33 of the safety guard 30 so as to be sucked from the suction port 25 into the fan case 20. The sucked air is pressurized and accelerated inside the fan case 20 and blown out forward via the air blowing pipe 55 that is connected to the discharge port provided on the upper front portion of the fan case 20, and the air (blown air) blown out is used for collecting fallen leaves and rubbishes to perform cleaning work.

(24) When the block prevention guard 40 is positioned on the operator side during the operation of the working machine, the operator's clothing can be prevented from being sucked to the safety guard 30. Even when the operator's clothing is sucked to the block prevention guard 40, since the average opening area of the apertures of the lattice 43 provided in the top surface opening 45 of the block prevention guard 40 is set to be far larger than that of the apertures of the lattice 33 of the safety guard 30, the operator's clothing can be prevented from being stuck to the surface of the block prevention guard 40, and thus the suction of the clothing to the safety guard 30 is reliably prevented and a sufficient area (space) for intake air is secured on the periphery of the safety guard 30.

(25) Further, even when the block prevention guard 40 is partially blocked by the clothing sucked thereto, a sufficient area for the air blow can be secured with a portion of the opening unblocked (the amount of the remaining portion of the opening when the block prevention guard 40 is partially blocked) because the intake amount of air depends on the opening area of the safety guard 30 (the lattice 33 portion thereof), and relatively large peripheral surface openings 44A, 44B, and 44C each having a substantially mountain-like shape are formed between the leg portions 42A and 42B, between the leg portions 42B and 42C, and between the leg portions 42C and 42A of the three leg portions, respectively, and further, the total opening area of the block prevention guard 40 obtained by adding the opening area of the lattice 43 of the top surface opening 45 to the opening areas of the peripheral surface openings 44A, 44B, and 44C is set to be larger than the opening area of the safety guard 30 (the lattice 33 portion thereof).

(26) Therefore, even when the block prevention guard 40 is partially blocked by the clothing sucked thereto, the intake amount of air is not reduced and the fluctuation of the engine speed is thus suppressed, and also the force of sucking the clothing is weakened to thereby suppress the operator's unpleasant feeling. As a result, the amplification of vibration and noise, the reduction in the amount of the blown air, the deterioration of the operability and the operation efficiency, and the like that were generated in the conventional example, can be effectively suppressed.

(27) Furthermore, since the opening area of the lattice 43 portion of the top surface opening 45 and the opening areas of the peripheral surface openings 44A, 44B, and 44C of the block prevention guard 40 are set to be considerably large as described above, as shown in FIGS. 6B and 7B, the amount of the portion of the block prevention guard 40 that protrudes laterally from the one side surface portion 20L of the fan case 20 can be reduced as compared to the amount of the protruding portion of the safety guard 60 in the conventional example shown in FIG. 8B, thereby enabling a required air blowing performance to be obtained without causing an increase in size or weight, deterioration of the operability of the working machine, or the like.

(28) In addition, the three longest main arc ribs 43a, 43b, and 43c of the lattice 43 portion provided in the top surface opening 45 are disposed so as to overlap the three longest main arc ribs 33a, 33b, and 33c of the lattice 33 portion of the safety guard 30, respectively, as seen in the left side view, and the three regions 43A, 43B, and 43C of the block prevention guard 40 are adapted to face directly the three regions 33A, 33B, and 33C of the safety guard 30, respectively, thereby enabling the inhaled air to be effectively regulated to improve the sucking efficiency.

(29) It should be noted that in the working machine 1 of the aforementioned embodiment, the average opening area of the apertures of the lattice 43 provided in the top surface opening 45 of the block prevention guard 40 is set to be larger than that of the apertures of the lattice 33 of the safety guard 30. However, even when the average opening area of the apertures of the lattice 43 provided in the top surface opening 45 of the block prevention guard 40 is set to be equal to that of the apertures of the lattice 33 of the safety guard 30, it is possible to, as long as the total opening area of the block prevention guard 40 is designed to be larger than the opening area of the safety guard 30 (the lattice 33 portion thereof), prevent a reduction in the intake amount of air and thus suppress the fluctuation of the engine speed when the block prevention guard 40 is partially blocked by the clothing sucked thereto, and also weaken the force of sucking the clothing and thus suppress the operator's unpleasant feeling. As a result, the amplification of vibration and noise, the reduction in the amount of the blown air, the deterioration of the operability and the operation efficiency, and the like that were generated in the conventional example, can be suppressed.

(30) It goes without saying that the shape and the like of the lattices 33 and 43 are not limited to those in the aforementioned embodiment, and there is no problem in adopting any patterns other than the geometric pattern. Further, in the aforementioned embodiment, the block prevention guard 40 has three leg portions, but as a matter of course, the block prevention guard 40 may have two, four, or more leg portions. Furthermore, the leg portions of the block prevention guard 40 may be omitted, and the block prevention guard that has the top surface opening with a curved surface, for example, may be provided so as to face the suction port 25.

(31) Moreover, the aforementioned embodiment has described an example in which the present invention is applied to a hand-held air blowing cleaner (power blower). However, the present invention can be applied not only to a hand-held air blowing cleaner but also to a power sprayer that sprays chemicals or the like with the use of air (blown air) discharged from an air blower, and the like, and a portable power working machine of a shouldering strap type as well as a hand-held type.