Brushing – scrubbing – and general cleaning – Machines – With air blast or suction
Reexamination Certificate
2000-09-18
2001-12-04
Till, Terrence R. (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
With air blast or suction
C015S330000, C181S225000
Reexamination Certificate
active
06324720
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of portable blowers. More particularly, the present invention provides a portable blower including sound absorbing material within the blower tube to reduce the amount of noise or acoustic energy escaping from the blower.
BACKGROUND
Portable blowers are in common use by homeowners and professionals to remove debris from yards and driveways without water or other equipment such as rakes or brooms. The portable blowers can be powered by either an electric motor or a gas-powered motor. Furthermore, some of the blowers can be converted into vacuum units in which leaves or similar debris can be vacuumed into a bag or other container.
When operated as blowers, the units provide a sweeping action using a fast moving stream of air produced by an impeller rotating within the housing of the blower. The impeller draws air into the unit through an inlet and forces the air out of the unit through an outlet. An exhaust or blower tube is typically fitted over the outlet to contain the air stream to a nozzle at the end of the blower tube. The length of the blower tube typically allows a user to stand and hold the portable blower while locating the nozzle near the ground. In addition, the nozzle outlet opening is typically smaller than the outlet at the housing to increase the velocity of the air as it exits the nozzle at the end of the blower tube.
Although portable blower units provide the ability to move debris without using water, rakes, brooms, etc., they can raise issues regarding noise during use. Because the blowers are typically used outside, the noise generated by the blowers has typically been of reduced importance. With their increasing use, however, the noise generated by the blower units has been receiving heightened attention. Furthermore, the noise generated by the portable blowers is increasing as the blowers become more powerful to improve their ability to move debris.
One attempt at addressing noise generated by portable blower units disclosed in U.S. Pat. No. 5,195,208 (Yamami et al.) is directed at blowers designed to be carried on the backs of the operators. The noise produced by the blower unit is reduced by essentially placing the unit, including the motor and the blower portions, between sound absorbing sheets located on at least two sides and the rear of the unit. Although this approach may be helpful in reducing the noise generated by backpack-mounted blower units, it does not address the needs of hand-held blowers, nor does it specifically address the noise generated at the inlet of air into the housing or at the exit of air from the outlet of the housing.
SUMMARY OF THE INVENTION
The present invention provides for noise reduction during operation of a portable blower by reducing the noise or acoustic energy escaping from the blower. Noise escaping from the blower tube is attenuated through the use of sound absorbing material located around a passageway within the blower tube. By exposing substantial portions of the inner surface of the sound absorbing material to the air moving through the passageway, acoustic energy contained within the airstream can be absorbed by the sound absorbing material.
The sound absorbing material and inserts of the present invention preferably attenuate acoustic energy while limiting negative impact on airstream velocity and/or volume. In preferred embodiments, the sound absorbing inserts may include flared upstream and downstream ends to maintain airstream velocity and/or volume as air passes through the passageway formed in the sound absorbing insert.
In preferred embodiments, the sound absorbing material is provided in connection with an insert that can be located within a blower tube. Even more preferably, the insert can be inserted into existing blower tubes not originally designed to accept sound absorbing inserts.
In one aspect, the present invention provides a portable blower having a blower tube attached to a housing outlet. Sound absorbing material is located within the blower tube and includes an inner surface located about a main passageway for air moving through the blower tube, wherein at least about 50% or more of the inner surface of the sound absorbing material located about the main passageway is exposed to the air moving through the main passageway.
In another aspect, the present invention provides a portable blower having a blower tube attached to a housing outlet. The blower tube includes an upstream end and a nozzle with the blower tube tapering from the upstream end to the nozzle. A sound absorbing insert is located within the blower tube and includes an inner surface located about a main passageway for air moving through the blower tube. The sound absorbing insert is retained within the blower tube by an interference fit with the tapering blower tube.
In another aspect, the present invention provides a portable blower having a blower tube attached to a housing outlet. A sound absorbing insert is sized to fit within the blower tube and includes a main passageway for air passing through the sound absorbing insert. The sound absorbing insert also includes sound absorbing material having an inner surface located about the main passageway, wherein at least about 50% or more of the main passageway is open to the inner surface of the sound absorbing material.
In another aspect, the present invention provides a portable blower having a blower tube attached to a housing outlet. A sound absorbing insert is sized to fit within the blower tube, the sound absorbing insert including an insert frame having an upstream end, a downstream end, and at least one support strut between the upstream end and the downstream end. The sound absorbing insert also includes a main passageway for air passing through the sound absorbing insert, the main passageway located between the upstream end of the insert frame and the downstream end of the insert frame. The sound absorbing insert also includes sound absorbing material having an inner surface located about the main passageway between the upstream end of the insert frame and the downstream end of the insert frame. A substantial portion of the main passageway is open to the inner surface of the sound absorbing material.
In another aspect, the present invention provides a sound absorbing insert for a blower tube of a portable blower. The sound absorbing insert includes an insert frame having an upstream end, a downstream end, and at least one support strut between the upstream end and the downstream end. The sound absorbing insert also includes a main passageway for air passing through the sound absorbing insert, the main passageway being located between the upstream end of the insert frame and the downstream end of the insert frame. The sound absorbing insert further includes sound absorbing material having an inner surface located about the main passageway between the upstream end of the insert frame and the downstream end of the insert frame, wherein a substantial portion of the main passageway is open to the inner surface of the sound absorbing material.
In another aspect, the present invention provides a method of attenuating the acoustic energy produced by a portable blower having a blower tube. The acoustic energy is attenuated by placing a sound absorbing insert within the blower tube, the sound absorbing insert including an insert frame having an upstream end, a downstream end, and at least one support strut between the upstream end and the downstream end. The sound absorbing insert also includes a main passageway for air passing through the sound absorbing insert, the main passageway located between the upstream end of the insert frame and the downstream end of the insert frame. The sound absorbing further includes sound absorbing material having an inner surface located about the main passageway between the upstream end of the insert frame and the downstream end of the insert frame, wherein a substantial portion of the main passageway is open to the inner surface of the sound absorbing material.
These and other featu
Beckey Thomas J.
Lund Rodney D.
Porter Steve R.
Shaffer Chadwick A.
Svoboda Steven J.
Mueting Raasch & Gebhardt, P.A.
The Toro Company
Till Terrence R.
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