Patent Publication Number: US-5289612-A

Title: Noise reduction system for hard body vacuum

Description:
TECHNICAL FIELD 
     This invention relates to a noise reduction system, and more particularly to a noise reduction system for use with an upright vacuum cleaner. 
     BACKGROUND ART 
     In a vacuum cleaner a primary source of noise is the exhaust air flow. A goal of vacuum cleaner manufacturers is to minimize the exhaust air flow noise to reduce as much as possible the annoyance to the vacuum cleaner operator. 
     Vacuum cleaner manufactures have taken different approaches to constructing noise reduction systems. These noise reduction systems have been utilized in both conventional and up right vacuum cleaners. One approach is taught in U.S. Pat. No. 2,340,437 to Stoner and in U.S. Pat. No. 4,617,034 to Ikezaki et al., which each disclose a vacuum leaner having a resonant muffler formed within the cleaner. These resonant chambers are designed to attenuate the sound waves over a certain range of frequency. 
     An alternative approach to reducing noise may be seen in U.S. Pat. No. 3,218,783 to Ripple and U.S. Pat. No. 4,446,594 to Watanabe et al., which disclose the use of sound absorbing material lining the exhaust passageway as a means of reducing exhaust noise. 
     U.S. Pat. No. 4,970,753 to Herron, Jr. assigned to Ryobi Motor Products Corp., discloses a cartridge which is provided for selective installation within the vacuum cleaner. Exhaust air flows through the cartridge which is configured to interfere with the free flow of the exhaust. The cartridge is a two-part unit wherein each part includes an array of parallel baffle plates which are interleaved with the array of baffle plates of the other part juxtaposed to the baffle plates of the opposing part to form a complete air flow baffle cartridge. The baffle plates for a labyrinth causing the air to undergo a plurality of changes of direction prior to leaving the vacuum cleaner, thereby reducing energy from the air flow. 
     The present invention is directed to improving know noise-reduction systems for use in upright vacuum cleaners. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an upright vacuum cleaner with an improved noise reduction system. 
     A feature of the present invention is to provide a baffle chamber having a series of baffles for baffling the exhaust noise prior to venting the same to atmosphere. 
     A further object of the present invention is to provide an upright vacuum cleaner having a head assembly and an electric motor for driving a blower. A rigid filter bag body is provided which is attached in upright relation to the head assembly. The rigid filter bag body has a fixed housing and a removable cover which defines an enclosed cavity therebetween. The housing is provided with a dirty air inlet in communication with the blower and an exhaust vent for venting filtered exhaust air to atmosphere. A muffler is provided which is affixed to the housing in a region of the exhaust vent which defines a baffle chamber therebetween. The muffler has an air entrance spaced from the exhaust vent which requires the exhaust air exiting the cavity to flow through the baffle chamber. A series of baffles are provided which are located within the baffle chamber between the air entrance and the exhaust vent for reducing exhaust air noise. 
     Another object of the present invention is to provide a noise reduction system for use with an upright vacuum cleaner. The noise reduction system has a first member and a second member which cooperate to form a rigid housing. The housing defines a cavity which encloses a dirty air inlet. Either the first member or the second member defines an exhaust vent for venting filtered exhaust air to atmosphere. A muffler is provided which cooperates with either the first member or the second member to form a baffle chamber. The muffler defines an air entrance spaced a distance from the exhaust vent requiring exhaust air exiting the cavity to flow through the baffle chamber. A series of baffles located are within the baffle chamber between the air entrance and the exhaust vent to reduce exhaust air noise. 
     Still another object of the present invention is to provide an upright vacuum cleaner having a head assembly and an electric motor for driving a blower. The vacuum cleaner has a body defining an exhaust vent. A cover is provided which cooperates with the body to form a rigid housing which is attached in upright relation to the head assembly. The housing defines an enclosed cavity. A dirt tube is provided which is located within the housing and in communication with the head assembly and the exhaust vent. The dirt tube has a muffler integrally formed thereon. The muffler is affixed to the body adjacent the exhaust vent so as to define a baffle chamber therebetween. The muffler has formed therein an air entrance spaced from the exhaust vent requiring exhaust air exiting the cavity to flow through the baffle chamber. A series of baffles are located within the baffle chamber between the air entrance and the exhaust vent for reducing exhaust air noise. 
     The above objects, features, and advantages of the present invention are readily apparent from the following detailed description of the invention when taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an upright vacuum cleaner with the cover, the muffler and the dirty air inlet removed from the housing, showing the internal elements of the present invention; 
     FIG. 2 is a perspective view of the rigid filter bag body showing the cover and filter bag removed exposing the muffler and dirty air inlet positioned against the housing in accordance with the present invention; 
     FIG. 3 is a cross-section of the invention showing the housing and cover cooperating to form a cavity, and showing major elements of the present invention; 
     FIG. 4 is a perspective view of the housing showing the exhaust vent in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The preferred embodiment shown in FIGS. 1 through 4 illustrates an upright rigid body vacuum cleaner 10. 
     As shown in FIG. 1, the vacuum cleaner 10, has a head assembly 12 which contains an electric motor 14 and a blower 16. A rigid filter bag body 18 cooperates with the head assembly 12. FIG. 2 shows that the rigid filter bag body 18 is formed from a housing 20 and a removable cover 22. A cavity 23 is formed therebetween. 
     The housing 20 defines an air aperture 24 which cooperates with a dirt tube or dirty air inlet 26 to allow dirty air to flow from the blower 16 in the head assembly 12 into the rigid filter bag body 18. The housing 20 also defines exhaust vents 28 for venting filtered exhaust air to atmosphere. The exhaust vents 28 comprises both a plurality of apertures 28a in the housing 20 as well as a directional duct 28b for directing vented exhaust air. FIG. 4 best illustrates the exhaust vents 28 formed within the housing 20. The housing 20 also has a wire guide 30 which directs the wires contained within the vacuum cleaner 10. 
     Also shown in FIG. 1 is the dirty air inlet 26. The air inlet 26 has a mounting portion 32 located at one end and a muffler 34 integrally formed at the other end of the dirty air inlet 26. The muffler 34 is longitudinally aligned with the air inlet 26 such that the muffler 34 extends upward in longitudinal alignment from the air inlet 26. The muffler 34 has a flange 36 which surrounds the muffler and cooperates with the housing 20 such that the muffler 34 and the housing 20 form a baffle chamber 38 when the muffler 34 is affixed to the housing 20. The muller has a series of baffles 40 which are connected to the muffler 34 in parallel alignment generally perpendicularly to the longitudinal axis of the air inlet 26. The baffles 40 extend across the muffler 34 and contact the flange 36, the baffles 40 project away from the muffler 34 toward the housing 20. 
     As shown in FIGS. 2 and 3, the housing 20 also has a series of baffles 40a which are similar in shape and size to the baffles 40 affixed to the muffler 34. When the muffler 34 and housing 20 are joined, the baffles 40 and 40a are interleaved and juxtaposed relative to each to ensure that the exhaust air travels in an S-shaped pattern through the baffle chamber to reduce the exhaust air noise. The flange 36 on the muffler 34 cooperate with the housing 20 in such a fashion so as to ensure that the baffle chamber is generally air sealed. The muffler 34 has a plurality of air entrance apertures 42 which allow exhaust air to move from the cavity 23 into the baffle chamber 38. 
     FIG. 2 also shows a filter bag 44 connected to the air inlet 26. The filter bag 42 is a porous material which filters dirty air and traps debris contained in the dirty air passing therethrough. As shown in FIG. 3, the muffler 34 is situated within the cavity 23 such that air must go through the air entrance apertures 42 in the muffler 34 prior to exiting the rigid filter bag body 18 through the exhaust vents 28. The exhaust vents 28 are best shown in FIGS. 1 through 3. 
     As shown in FIG. 2, the air inlet 26 has a rubber seal 46 which is located between the mounting portion 32 of the air inlet 26 and the air aperture 24 of the head assembly 12 to ensure that dirty air is not leaked into the cavity 23. 
     In operation, as depicted in FIG. 3, the blower 16 forces dirty air into the dirty air inlet 26 which pushes the dirty air into the filter bag 44. The filter bag 44 filters the dirty air of debris, retaining the debris in the filter bag 44. The filtered exhaust air then moves through the air entrance apertures 42 of the muffler 34 into the baffle chamber 38. The baffles 40 and 40a cause the exhaust air to be redirected a number of times which decreases the energy and related noise of the exhaust air. The exhaust air then is vented to atmosphere through the exhaust vents 28. Exhaust air travels from the cavity 23 through the baffle chamber 38 and is vented to atmosphere because the air pressure within the cavity 23 is greater than the external air pressure. Accordingly, the exhaust air travels toward the lower pressure, i.e. from the cavity 23 to atmosphere through the exhaust vents 28. 
     While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.