Cutlery – Combined cutlery or combined with ancillary feature – With material-holder or disposal
Reexamination Certificate
1998-08-19
2001-05-22
Rada, Rinaldi I. (Department: 3724)
Cutlery
Combined cutlery or combined with ancillary feature
With material-holder or disposal
C030S133000
Reexamination Certificate
active
06233831
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a dust collector-equipped power cutter, and in particular to a power transmission mechanism for a portable type dust collector-equipped power cutter that includes a cutting disk and a dust-sucking fan that are driven by a prime mover.
A conventional portable type dust collector-equipped power machine of this kind, which is currently produced, is generally constituted by a main body provided with a prime mover, such as a small air-cooled two stroke internal combustion engine or an electric motor, a cutting head portion having a cutting disk that is rotated by the prime mover and having a safety cover, and a dust-sucking fan attached to the safety cover for sucking dust from the site of the cutting and discharging dust generated by the power cutter when it is operated.
In the conventional portable type dust collector-equipped power cutter of the aforementioned type, the speed of rotation of the prime mover is reduced before it is transmitted to the cutting disk, thereby to rotate the cutting disk at a lower rotational speed than the rotational speed of the prime mover, and at the same time, the reduced speed of the prime mover is taken off so as to transmit it to the dust-sucking fan, thereby to rotate the dust-sucking fan. Therefore, the speed of rotation of the dust-sucking fan tends to become slow, thus making it difficult to achieve a sufficient dust-sucking capability of the dust-sucking fan.
With a view to overcoming the problem mentioned above, the owner of the present invention has previously proposed in Japanese Patent Application No. H9-30786 (Japanese Patent Laid-Open Publication 10-225925) a dust collector-equipped power cutter which provides rotation of the dust-sucking fan thereof at high speed. In that dust collector-equipped power cutter the output shaft of a prime mover is operably connected with a centrifugal clutch having a clutch drum to which a pulley of smaller diameter as well as a pulley of larger diameter are integrally formed such that, by means of the prime mover, the cutting disk can be rotated through a combination of the aforementioned smaller pulley and a first belt at a lower speed, and at the same time, the dust-sucking fan can be rotated through a combination of the aforementioned larger pulley and a second belt at a higher speed. According to this structure, the dust-sucking fan of the dust collector-equipped power cutter rotates at a higher speed, thereby enhancing the suction force of the dust-sucking fan and hence enabling the dust generated by the operation of the cutting disk to be sufficiently sucked away from the cutting site and discharged.
However, since the rotation from the output shaft of the prime mover is individually transmitted to the cutting disk and to the dust-sucking fan through a combination of the aforementioned smaller pulley and a first belt, and through a combination of the aforementioned larger pulley and a second belt, respectively, the number of parts for the power transmitting mechanism required between the output shaft of the prime mover and the cutting disk or the dust-sucking fan is inevitably increased and hence the layout and construction of the parts is rather complicated, thus leading to an increase in manufacturing cost of the entire transmission mechanism as well as in the cost of assembling it.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a dust collector-equipped power. cutter wherein the power transmitting mechanism from the prime mover to the cutting disk and to the dust-sucking fan can be simplified, thereby enabling the power cutter to become compact in structure as a whole.
With a view to attaining the aforementioned object, the present invention provides a dust collector-equipped power cutter which comprises a prime mover, a cutter, a dust-sucking fan, and a belt-driven power transmission mechanism for transmitting revolving power from the prime mover to the cutting disk and to the dust-sucking fan. The belt-driven power transmission mechanism is constructed such that the rotation of the prime mover is transmitted through a single belt to a cutter-driving pulley for the cutting disk and to a fan-driving pulley for the dust-sucking fan.
In a preferred embodiment, a dust collector-equipped power cutter includes a prime mover having an output shaft, a centrifugal clutch operably connected with the output shaft of the prime mover and having a pulley portion constituted by a boss portion of a clutch drum of the clutch, a cutting disk, and a dust-sucking fan having a fan-driving pulley fixed externally to a driving shaft of the dust-sucking fan. A belt-driven power transmission mechanism for transmitting rotation from the prime mover to the cutting disk and to the dust-sucking fan is composed of an intermediate relay double pulley for the cutting disk, and a single belt, preferably a V-ribbed belt, that is wound around the pulley portion, the fan-driving pulley and the intermediate relay double pulley.
In another embodiment, an impeller is attached to the driving shaft of the dust-sucking fan, and a timing belt is wound around a smaller pulley portion of the intermediate relay double pulley and a final pulley which is attached to one end portion of a cutting disk-driving shaft that fixedly carries the cutting disk at the other end portion thereof.
In a further embodiment, the diameter of pulley portion of the centrifugal clutch is larger than the diameter of the fan-driving pulley but smaller than the diameter of a larger pulley portion of the intermediate relay double pulley, and the diameter of the smaller pulley portion of the intermediate relay double pulley is smaller than the diameter of the final pulley.
In a dust collector-equipped power cutter of this invention, which is constructed as described above, since the belt-driven power transmission mechanism for transmitting rotation from the prime mover to the cutting disk and to the dust-sucking fan is constructed such that the rotation is transmitted from the pulley of the prime mover through a single V-ribbed belt to a cutter-driving pulley for the cutting disk and to a fan-driving pulley for the dust-sucking fan, the power transmitting mechanism can be simplified, thus making it possible to reduce the number of parts as compared with the conventional power transmitting mechanism and to simplify the layout of the power transmitting mechanism thereby saving the cost for manufacturing and assembling the transmission mechanism as a whole.
Further, although the fan-driving pulley and the intermediate relay double pulley are designed to be rotated using a single V-ribbed belt, the diameters of both the fan-driving pulley and the intermediate relay double pulley are made different, respectively, from the diameter of the pulley of the prime mover so as to rotate the fan-driving pulley at a higher speed and at the same time, to rotate the intermediate relay double pulley at a lower speed, whereby the speeds of rotation of both the dust-sucking fan and cutting disk can be easily set to suitable levels, respectively, for optimum operations thereof.
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Iida Giichi
Kobayashi Fujio
Yamami Hirofumi
Baker & Botts L.L.P.
Flores-Saánchez Omar
Kioritz & Corporation
Rada Rinaldi I.
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