AIR CLEANER FOR USE WITH A PORTABLE ENGINE

Abstract: An air cleaner (47) having a main casing (309) fixed to a suction port (305) of a carburettor (49), a cap casing (319) removably fitted to said main casing (309) and a filter made (315) of porous material which is held between the main casing (309) and the cap (319). The air cleaner (47) comprises a space portion (389) provided in one of said main casing (309) and said cap casing (319) for receiving the filter (315). Furthermore, support legs (331, 333) are provided which project inside the space portion (329) for being inserted into fitting holes (335) which pass through the filter (315).

Description: The present invention relates to an air cleaner and in particular to an air cleaner for a portable engine adopted for a portable working apparatus such as a weed cutter. In particular, the present invention relates to an air cleaner which comprises a main casing fixed to a suction port of a carburettor of a portable engine, a cap casing being removably fitted to said main casing, said filter being held between the main casing and the cap casing. In conventional air cleaners of this type, the filter will be lost when the cap casing is removed from the main casing. To prevent this, in conventional air cleaners the periphery of the filter is formed larger than the inner diameter of a space portion for receiving the filter to compress the periphery of the filter when it is pushed into said space portion, thereby holding the filter. To maintain a predetermined supporting force at the periphery of such an oversized filter, it is necessary to enlarge a dimensional difference between the periphery of the filter and the inner diameter of the space portion to increase the compression dimension. Due to this, the filter however may protrude from said space portion, or wrinkles may be formed on the surfgace of the filter, thereby causing deformation of the filter. From US-A-29 99 562 an air cleaner according to the precharacterizing part of claim 1 is known having a main casing, a cap casing removably fitted to the main casing and a filter being received in that cap casing. Said main casing being fixed to the air suction port of the engine and having an opening to communicate with the air suction port of the engine. The filter is made of porous material for cleaning air which is sucked into the air suction port. Said cap casing has at least one protection support for supporting the filter. In this air cleaner however, when removing the cap casing and the filter element, there is nothing to prevent the dust from the dust side of the filter element from being taken into the inlet port of the carburettor. It is an object of the present invention to arrive at an improved air cleaner in which the filter is securely held when the cap casing is opened and in which the dust is prevented from being taken into the inlet port of the carburetor when removing the cap casing and the filter element. This object is achieved by the characterizing features of claim 1. A further advantage of the present invention is to arrive at an improved air cleaner in which the filter is not deformed. Furthermore, it is another advantage of the present invention to arrive at an air cleaner into which the filter can be easily installed and from which the filter can be easily removed. Further improvements and preferred embodiments of the inventive air cleaner are defined in the sub-claims. The inventive air cleaner is not restricted to a use in connection with portable engines but can be used with engines of different types. One way of carrying out the invention is described in detail below with reference to drawings which illustrate only one specific embodiment, in which: Fig 1 is a front view, partly broken, showing an air cleaner connected to a portable engine; Fig 2 is a cross-sectional view showing the details of the air cleaner; Fig 3 is an external view showing the air cleaner; and Fig 4 is a cross-sectional view showing the air cleaner. In Fig 1 there is shown a portable engine comprising an air filter according to an embodiment of the present invention. As shown in Fig 1, an engine cylinder 5 is fixed on top of a crankcase (not shown). Reference numeral 15 depicts a centrifugal clutch which is fitted to the front side of a magnet wheel (not shown). A fan 23 having a plurality of fins is fixed to the rear side of the magnet wheel and a fan cover 25 for covering the fan 23 is fixed to the front side of the crankcase to guide a blow of the fan 23 first upwards and then rearwards. A cylinder cover 29 covers both sides of the engine cylinder 5 and is positioned in series with the fan cover 25 to guide the blow towards the periphery of the engine cylinder 5. A partition 33 for covering a step formed on one side of the fan cover 25 and the cylinder cover 29 is integrally formed with the cylinder cover 29. A partition 35 for covering another step formed on the other sides of the fan cover 25 and the cylinder cover 29 is integrally formed with one side of the crankcase and projects upwards. An ignition coil 37 has an iron coil 39 which is fixed to the partition 35 by screws 41. The current of the ignition coil 37 is transmitted through a code 43 to an ignition plug 45 located on top of the engine cylinder 5, and discharged from the ignition coil 37. A carburettor 49 having an air cleaner 47 is fitted to one side of the engine cylinder 5, and a muffler cover 51 including a muffler (not shown) is fitted to the other side of the engine cylinder 5. Figs 2 to 4 show the details of the air cleaner 47. A main casing 309 of the air cleaner 47 has an opening 307 which communicates with a suction port 305 of the carburettor 49. The casing 309 is fixed to the carburettor 49 with bolts 311. A choke valve 313 is fitted by a bolt 311 and opens and closes the opening 307. Ribs 317 are formed inside the casing 309 to support a felt like or sponge like porous filter 315. A cap casing 319 is removably fitted at its lower end to a fitting portion 323 of the main casing 309 by a fitting pin 321 to hold the filter 315. A hook 325 projecting from the tope of the cap casing 319 is stopped by a stopping portion 327 of the main casing 309 due to the resiliency. A space 329 for receiving the filter 315 is fomed in the cap casing 319. Supports 331 and 333 projecting inside the cap casing 319 are removably inserted into holes 335 which are formed to pass through the filter 315. The filter 315 is held by a partition 337 for separating a part of the interior of the cap casing 319, by a step 339 of the support 333, and by the main casing 309. A muffling chamber 343 is formed between the cap casing 319 and an outer wall 341 to communicate a chamber 345 of the cap casing 319 with the atmosphere. A cover 347 for covering the top of the carburettor 49 is fixed to the upper part of the cap casing 319. According to the above arrangement, the atmosphere enters into the chamber 345 through the muffling chamber 343 according to the suction force of the engine, and is sucked by the suction port 305 of the carburettor 49 through the filter 315 and the opening 307. The filter 315 may be removed by removing the hook 325 from the stopping portion 327 with fingers and by turning the cap casing 319 around the pin 321. The filter 315 is then taken out and cleaned. To install the filter 315, the cap casing 319 is kept to be opened, and the fitting holes 335 of the filter 315 are pushed toward the supports 331 and 333 of the cap casing 319 to place the filter 315 in the space 329. After than, the cap casing 319 is closed, and the hook 325 is engaged with the stopping portion 327. Since the inventive air cleaner is constituted as described above, the filter is not deformed, held securely when the cap casing is opened, thereby ensuring that the filter will not drop. Furthermore, the filter is easy to install and easy to remove.

Claims: An air cleaner for an engine having an air suction port (305), comprising a main casing (309) adapted to be fixed to the air suction port (305) of the engine and having an opening (307) to communicate with the air suction port of the engine, a cap casing (319) removably fitted to the main casing, a filter (315) made of porous material for cleaning air sucked into the air suction port (305), said cap casing (319) having a receiving portion (329) to which the filter (315) is adapted to he fitted, the filter (315) having at least one fitting hole (335), and at least one projection support (331,333) being provided in the receiving portion (329) of the cap casing (319), said at least one support (331,333) heing adapted to be fitted to the at least one fitting hole (315) of the filter to support the filter (315), characterized in that a chamber (343) for communicating inside of the air cleaner with atmosphere is provided on said cap casing (319) so that the air is sucked therefrom through the filter (315) into the suction port (305). The air cleaner of claim 1, wherein the cap casing (319) is removably fitted to a fitting portion (323) of the main casing (309) by a fitting pin (321) so that the cap casing (319) is turned around the fitting pin (321) to be fitted on or removed from the main casing (309). The air cleaner of claims 1 or 2, further comprising a hook (325) for cooperating with a stopping portion (327) to removably fit the cap casing (319) to the main casing (309). The air cleaner of claims 2 or 3, wherein the fitting portion (323) is provided on a lower portion of the main casing (309), and the hook (325) is projectingly provided on an upper portion of the main casing (309) and the stopping portion (327) is provided on an upper portion of the cap casing (319). The air cleaner of claim 1 to 4, wherein a partition (337) defining the chamber (343) is provided in the receiving portion (329) of the cap casing (319). The air cleaner of one of claims 1 to 5, wherein a rib (317) is provided on the main casing (309) in order to support the filter (315) when the cap casing (319) is fitted on the main casing (309). The air cleaner of one of claims 1 to 6, wherein the main casing (309) is fixed at the vicinity of the opening (307) by a bolt (311), and a choke valve (313) is fitted to the main casing (309) by the bolt (311) so that the choke valve (311) opens or closes the opening (307). The air cleaner of one of claims 5 to 7, wherein the at least one support has a step (339), and the filter (315) is supported on the partition (337) and the step (339).

Inventors: EBINUMA, TAKANORI, KATOH, HIROSHI, SAKURAI, MITSUKO
Applicants: KOMATSU ZENOAH CO.
Application year: 1988
Main classification: F02M35
IPC codes: F02B75, F02M35, F02B63