Electric vacuum cleaner

Abstract: An object of the present invention is to provide an electric vacuum cleaner capable of securely maintaining an air-tightness between a dust collector chamber (32) and an electric blower chamber (48) with a simple structure thereof. The object of the present invention is achieved by means of forming a duct (33) communicating the dust collector chamber (32) for collecting dust with the electric blower chamber (48) accommodating an electric blower integrally with a structural body (1) of the cleaner.

Description: The present invention relates to an electric vacuum cleaner according to the preamble of claim 1. Such a vacuum cleaner is known from EP 0 391 338. In a conventional electric vacuum cleaner, as shown, e.g., in Japanese Patent Unexamined Publication No. 58-50923, an air-tight sealing between the dust collector chamber and the electric blower chamber is attained by abutting engagement between ribs of a body casing and a top casing. Further, concave-convex portions may be formed partially on abutment surfaces of the ribs so that an air-tightness is reinforced. Alternatively, a seal packing (such as a seal packing of moltprene) may be provided partially on the abutment surfaces of the ribs. Also, in a conventional electric vacuum cleaner, as shown, e.g., in Japanese Patent Unexamined Publication No. 61-209626, an accessory (nozzle) receptacle is formed rearward of the electric blower chamber, and a cover is mounted above the receptacle to open or close it. In the construction shown in Japanese Patent Unexamined Publication No. 58-50923, when the body casing and/or the top casing deforms, a gap occurs between the abutment surfaces of the ribs, thereby making it impossible to attain a sufficient air-tight sealing between the dust collector chamber and the electric blower chamber. Further, in case that the concave-convex portions are provided on distal ends of the ribs, the die must be formed with higher precision, thereby increasing in the mold expenses. In addition, in this case, the assembly of the component parts has to be performed very carefully, thereby necessitating an additional period of time for the assembly work. With the construction shown in Japanese Patent Unexamined Publication No. 61-209626, since the accessory receptacle is disposed in an exhaust air flow, a problem of how to prevent exhaust air from detouring arises. Another problem is that the mold is inevitably complicated. In addition, an opening/closing cover for covering the accessory receptacle has to be provided separately from the dust chamber cover. Prior art document EP-0 391 338 A1 discloses a vacuum cleaner having a dust collecting chamber and an electric blower chamber. These chambers are formed integrally with the housing of the vacuum cleaner. The chambers are communicated with each other through the opening within a separation wall between the two chambers. It is an object of the present invention to provide an electric vacuum cleaner having reduced noise emissions. This object is solved in accordance with the features of the independent claim. Dependent claims are directed on preferred embodiments of the invention. Fig. 1 is a vertical sectional view showing an embodiment of the present invention; Fig. 2 is a plan view showing the embodiment shown in Fig. 1 with a dust chamber cover removed; Fig. 3 is a plan view showing the embodiment shown in Fig. 1 with a top casing removed; Fig. 4 is a sectional view taken along the lines IV-IV shown in Fig. 1; and Fig. 5 is a sectional view taken along the lines V-V shown in Fig. 1. Referring to Figs. 1 to 3, a structural body 1 of an electric vacuum cleaner has its exterior defined by a lower casing 2 of a synthetic resin which is located at a lower position of the body, a dust chamber cover 3 of a synthetic resin which can be located at an upper position of the body, a top casing 4 of a synthetic resin, and a furniture guard 5 provided on outer peripheries of the casings for the purpose of cushioning. The structural body accommodates therein an electric blower 6, a cord reel 7, a dust collection bag 8, and so on. The lower casing 2 is provided at a front portion thereof with a front caster wheel 9 and at a rear portion thereof with rear wheels 10. A handle 11 and a holder 12 for holding an extension pipe (not shown) are integral with a front portion of the lower casing 2. The top casing 4 has at a front portion thereof an accessory storage rack 13, and at a rear portion thereof an openable and closable filter casing 14, and a removable filter 15. The accessory includes a tapered crevice nozzle 16 and a dusting nozzle 18 having a brush 17 attached to a front end of the nozzle. The crevice nozzle 16 and the dusting nozzle 18 can be stored inside the rack 13. A pedal switch 20 for switching over a power supply switch 19 and a pivotable pedal 22 for operating the cord reel 7 are provided on an upper surface of the top casing 4. The dust chamber cover 3 has a hook 23 integrally formed on a front portion thereof, which is in fitting engagement with a hooking hole 50 of the body casing 2, and has a clamp 24 provided on a rear end portion thereof for opening the cover. An inlet 25 for a hose (not shown) is formed in an upper portion of the dust chamber cover 3. The hose inlet 25 has a groove 26 in which a clamp of a hose joint (not shown) can be rotatably engaged. A rubber seal 27 is mounted to the dust chamber cover 3 by an inner cover 28 in order to maintain an air-tightness among the hose and the joint (not shown), and the dust collector section. The rubber seal 27 also serves to maintain an air-tightness between the dust chamber cover 3 and a cardboard 8a of a dust collection bag 8. The dust collection bag 8 is supported by a rib 29 formed on the lower casing 2 and a hinged mount 30. The dust chamber cover 3 is provided with a dust indicator 31 held in place by the inner cover 28 for indicating a time for the user to dispose of the collected dust. A dust collector chamber 32 having an opening on an upper portion thereof and an electric blower chamber 48 having an opening on an upper portion thereof are juxtaposed in the lower casing. A duct 33 is provided between the dust collector chamber 32 and the electric blower chamber 48, which communicates the dust collector chamber 32 with the electric blower chamber 48. The duct 33 is formed integrally with the lower casing 2 when it is formed. A guard rib 34 and a protection filter 35 are disposed on the side of the duct 33 which is closer to the dust collector chamber 32. The electric blower 6 is accommodated in the electric blower chamber 48 while being fixed in the forward and rearward position by rubber members 36 and 37 and an electric blower cover 40. The rubber member 36 is disposed in close contact with a sealing wall 38 of the electric blower chamber. The duct 33 has an entrance opening connected to the dust collector chamber 32, an area of which is smaller than that of an exit opening connected to the sealing wall 38, thereby reducing the noise generated by the electric blower 6 from being transmitted through the duct 33 to the dust collector chamber 32. The cord reel 7 is accommodated in a cord accommodating chamber 39 adjacent to the electric blower chamber 48. A printed circuit board 42 incorporating thereon a variable resistance slider 41 is mounted on the electric blower cover 40. A control member 43 for operating the variable resistance slider 41 is slidably mounted on the top casing 4. A semiconductor 44 is accommodated in a chamber 21 of a printed circuit board having an opening on an upper portion thereof which is formed integrally with an upper portion of the duct 33. A cover 46 is air-tightly mounted to the opening of the printed circuit board chamber 21 by means of a screw 47. The bottom of the printed circuit board chamber 21 includes a hole 45 through which the duct 33 communicates with the printed circuit board chamber 21. The furniture guard 5 is configured to surround the dust collector chamber 32 within the lower casing 2, and is mounted on the lower casing 2. A chamber 51 is provided between the dust collector chamber 32 and the electric blower chamber 48 for storing accessories together with the duct 33. The rack 13 of the top casing 4 is disposed to depend into the chamber 51. When the upper portion opening of the dust collector chamber 32 is closed by the dust chamber cover 3, the cover 3 extends over the rack 13 of the top casing 4. Under the condition where the upper portion opening of the dust collector chamber 32 is closed by the dust chamber cover 3, a wall 3a formed on the dust chamber cover 3 cooperates with a seal packing 49 provided on the edge of the upper portion opening of the dust collector chamber 32 to maintain an air-tightness between the dust collector chamber 32 and the rack 13. The seal packing 49 is integral with a furniture guard. As shown in Figs. 4 and 5, a cross-sectional configuration of the duct 33 is such that a lower part thereof is curved, while the remaining part, i.e., upper and side parts are flat. The duct 33 has a length dimension with which a movable die for forming the duct 33 can be moved into and out from the electric blower chamber 48. As shown in Fig. 1, a lower surface of the duct 33 is positioned higher than a bottom surface of the lower casing 2. As a result, a convex portion 1a is formed in the lower casing 2. An air exhaust port is formed in a portion of the electric blower cover 40. With the above-described construction, when the power supply switch 19 is turned on, air flows from the dust collector chamber 32 through the duct 33 into the electric blower 6 to be discharged to the inside of the electric blower chamber 48. Exhaust air from the electric blower chamber 48 flows through the filter 15 and the filter casing 14 to be discharged to the outside of the structural body 1. In this process, the duct 33 fulfils a secure air-tight sealing between the dust collector chamber 32 and the electric blower chamber 48. According to the present invention, since the duct communicating the dust collector chamber with the electric blower chamber is formed integrally with the structural body of the cleaner, it is possible to provide an electric vacuum cleaner which enables a secure air-tight sealing to be attained between the dust collector chamber and the electric blower chamber without requiring a complicated structure for this purpose. Further, according to the present invention, since an accessory storage chamber is formed between the dust collector chamber and the electric blower chamber, it is possible for the dust chamber cover covering the opening of the dust collector chamber to serve as a cover for extending over the accessory storage chamber. As a result, it is possible to provide an electric vacuum cleaner having a relatively small number of component parts and requiring a relatively small number of assembly processes.

Claims: An electric vacum cleaner having a structural body (1) in which a dust collector chamber (32) for collecting dust and an electric blower chamber (48) accommodating an electric blower (6) are disposed, the duct through which the dust collector chamber (32) and the electric blower chamber (48) communicate with each other being formed integrally with the structural body (1), characterized in that the duct (33) has an entrance opening connected to the dust collector chamber (32), an area of which is smaller than that of the exit opening connected to the electric blower chamber (48). A vacuum cleaner according to claim 1, characterized in that the cleaner is so constructed that a semiconductor (44) for controlling the electric power consumed by said electric blower (6) accommodated in said electric blower chamber (48) is cooled by air flowing through said duct. A vacuum cleaner according to claim 2, characterized in that the duct presents a cross-sectional configuration, at least a lower part of which is curved. A vacuum cleaner according to one of the claims 1 to 3, characterized in that the structural body includes at least a lower casing (2) in which the dust collector chamber (32) having an opening on an upper portion thereof and the electric blower chamber (48) having an opening on an upper portion thereof are disposed, a dust chamber cover (3) for covering said opening of said dust collector chamber (32), and a top casing (4) for covering the opening of the electric blower chamber (48), and that the duct is formed integrally with the lower casing (2). A vacuum cleaner according to claim 4, characterized in that the lower surface of the duct (33) is positioned higher than the bottom surface of the lower casing (2). A vacuum cleaner according to claim 4, characterized in that the length of the duct is set such that a movable die for forming said duct (33) can be moved into and out from said electric blower chamber (48). A vacuum cleaner according to claim 1 or 4, characterized in that the dust collector chamber (32) has an opening on an upper portion thereof, an accessory storage chamber is provided between the dust collector chamber (32) and the electric blower chamber (48), and a dust chamber cover (3) for covering said opening of said dust collector chamber (32) extends over said duct (33) and said accessory storage chamber (13).

Inventors: IWAO AKIRA, SUZUKI NARUHIKO, IWAO, AKIRA, SUZUKI, NARUHIKO
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 1992
Main classification: A47L5
IPC codes: A47L5, A47L9