Power tools with noise reduction features

Abstract

A power tool comprises: an air inlet; and an inlet muffler arranged in the air inlet, the inlet muffler comprising a plurality of inlet ports, each of the plurality of inlet ports comprising an outer peripheral surface defining a port aperture extending therethrough, and at least one of the plurality of inlet ports further comprising a damper material disposed on an outer peripheral surface of at least one inlet port and further defining a port aperture extending therethrough.

Description

Technical Field

[0001] The present disclosure relates to power tools, and more particularly to power tools for outdoor applications. In particular, the present disclosure relates to power tools having improved noise reduction features. Background Art

[0002] Power tools are generally utilized to more efficiently perform tasks that might otherwise require human labor. For example, power tools such as lawn mowers can replace traditional manual lawn mowers, compressors and aerators can replace hand pumps, snow blowers can replace shovels and plows, and chain saws can replace hand saws. People often utilize such power tools to perform tasks more efficiently and easily.

[0003] One problem with many power tools is the noise level produced during operation. This noise can come from the engine, fan blades, and other moving and stationary parts of the power tool. While it is possible to produce a power tool that gives up a certain level of performance simply by reducing the power and performance level of the power tool, the resulting product is not ideal for the user due to the lack of performance.

[0004] Therefore, improved power tools are desired that include noise reduction features without sacrificing performance. In particular, a power tool that includes reduced noise generation and improved performance features would be advantageous. Summary of the invention

[0005] Various aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0006] According to one aspect, the present disclosure relates to a power tool including an air inlet. The air inlet may be in fluid communication with a noise generating element (e.g., an engine, a fan blade, etc.) of the power tool. In some cases, an airflow may pass through the air inlet and move toward the noise generating element. The power tool may further include an inlet muffler in fluid communication with the air inlet. The inlet muffler may include a plurality of inlet ports. Each of the plurality of inlet ports may include an outer peripheral surface defining a port aperture therethrough. At least one of the plurality of inlet ports may further include a damper material, which is disposed on an outer peripheral surface of at least one inlet port and further defines a port aperture therethrough.

[0007] According to one aspect, a power tool may define an operating power to damping loss ratio of at least 1.25 Where, dB M is the sound insulation intensity measured when the outdoor power tool is equipped with an air inlet muffler, dB Uis the non-silenced intensity measured when the outdoor power tool is not equipped with an air inlet muffler, P M is the maximum muffled operating power capacity measured when the outdoor power tool is equipped with an air inlet muffler, and P U It is the un-muffled operating power capacity measured when the outdoor power tool is not equipped with an air inlet muffler.

[0008] According to one aspect, a method for damping a power tool may include aligning an inlet muffler relative to an air inlet of the power tool, and mounting the inlet muffler on the air inlet. The inlet muffler may include a plurality of inlet ports, each of which includes an outer peripheral surface defining a port aperture therethrough. At least one of the plurality of inlet ports may further include a damper material disposed on an outer peripheral surface of at least one inlet port and further defining a port aperture therethrough. In one embodiment, the method may further include assembling at least one of the plurality of inlet ports before mounting the inlet muffler on the air inlet. Assembling at least one inlet port may include mounting a damper material on a frame, wherein an inner peripheral surface of the damper material expands when the damper material is mounted on the frame. The method may also include attaching the plurality of inlet ports together to form the inlet muffler after assembling at least one of the plurality of inlet ports.

[0009] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The description sets forth a complete and enabling disclosure of the invention, including the best mode thereof, to one of ordinary skill in the art with reference to the accompanying drawings.

[0011] Figure 1 A schematic diagram including a power tool according to an embodiment of the present disclosure;

[0012] Figure 2 is a side view of a blower according to an embodiment of the present disclosure;

[0013] Figure 3A is a rear perspective view of components of a blower according to an embodiment of the present disclosure;

[0014] Figure 3B is a perspective view of a frame of a blower according to an embodiment of the present disclosure;

[0015] Figure 3C is a perspective view of a damper of a blower according to an embodiment of the present disclosure;

[0016] Figure 4 is a cross-sectional view of a portion of a main body of a blower according to an embodiment of the present disclosure;

[0017] Figure 5 is a cross-sectional view of another portion of the blower body according to an embodiment of the present disclosure;

[0018] Figure 6 is a perspective view of a blower according to an embodiment of the present disclosure;

[0019] Figure 7 is a perspective view of a portion of an inlet portion of a blower according to an embodiment of the present disclosure;

[0020] Fig. 8A and Figure 8B is a perspective view of a portion of a blower body according to an embodiment of the present disclosure;

[0021] 9A to 9C is a perspective view of an inlet muffler of a blower according to an embodiment of the present disclosure;

[0022] Fig.10 is a schematic diagram of an inlet port of a blower according to an embodiment of the present disclosure;

[0023] Fig.11 is a perspective view of an inlet portion of an inlet muffler including a blower according to an embodiment of the present disclosure;

[0024] Fig.12 is a front view of an axial flow fan of a blower according to an embodiment of the present disclosure;

[0025] Fig.13 is a side view of an axial flow fan of a blower according to an embodiment of the present disclosure;

[0026] Fig.14 is a cross-sectional view of a portion of a blower body including a stator according to an embodiment of the present disclosure;

[0027] Fig.15 is a front perspective view of a blower including a leaf scraper according to an embodiment of the present disclosure;

[0028] Fig.16 is a cross-sectional view of a portion of a blower body including a noise cancellation system according to an embodiment of the present disclosure;

[0029] Fig.17 is a cutaway perspective view of a portion of a blower including a sound damping element according to an embodiment of the present disclosure;

[0030] Fig.18 is a front view of an axial flow fan of a blower according to an embodiment of the present disclosure;

[0031] FIG. 19A to FIG. 19G is a perspective view of a different power tool including an inlet muffler according to an embodiment of the present disclosure; and

[0032] Fig. 20 A flow chart of a damping method for a power tool according to an embodiment of the present disclosure is included. DETAILED DESCRIPTION

[0033] Reference will now be made in detail to embodiments of the present invention, one or more embodiments of which are illustrated in the drawings. The repeated use of reference numerals in this specification and in the drawings is to indicate the same or similar features or elements of the present invention. Each embodiment is provided in a manner to explain the present invention without limiting the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as part of one embodiment may be used together with another embodiment to produce a further embodiment. Therefore, the present invention is intended to encompass such modifications and variations within the scope of the appended claims and their equivalents.

[0034] As used herein, the terms "first," "second," and "third" are used interchangeably to distinguish one component from another and do not necessarily indicate the order or importance of the various components. As used herein, approximate terms such as "substantially" or "approximately" include values ​​within ten percent greater or less than the stated value. When used in the context of an angle or direction, such terms include angles or directions within ten degrees greater or less than the stated angle or direction. For example, "substantially vertical" includes directions within ten degrees in any direction of vertical (e.g., clockwise or counterclockwise).

[0035] Figure 1 An exemplary schematic diagram of a power tool 100 with noise reduction features according to the present disclosure is shown. In one embodiment, the power tool 100 with noise reduction features may include a power tool 102, such as an outdoor power tool like a lawn mower, a compressor, an inflator, a forced air heater, a pump, a fluid pump, a generator, a snow blower, a pressure washer, a chain saw, an edger, a trimmer, or a vacuum. In one embodiment, the power tool 102 may be an electric tool such as a battery-powered power tool or a corded power tool. In another embodiment, the power tool 102 may be a gas-powered tool.

[0036] The power tool 102 may include a noise generating element 104, such as an engine, a fan blade or impeller, a compressor, a brush or a stator, etc. In some cases, the noise generating element 104 may include one or more stationary or moving components that generate noise by resonating with the airflow passing therethrough. In other cases, the noise generating element 104 may include an internal combustion engine. In other cases, the noise generating element 104 may include multiple components, such as an internal combustion engine that drives rotating fan blades.

[0037] The noise generating element 104 can be in fluid communication with (e.g., coupled to) the air inlet port 106 of the power tool 102 via an aperture 108 extending between the noise generating element 104 and the air inlet port 106. In one embodiment, the air inlet port 106 can define the outermost boundary of the air inlet port 106. The inlet muffler 110 can be arranged on or adjacent to the air inlet port 106. In some cases, the inlet muffler 110 can be selectively detached from the air inlet port 106. In this way, the inlet muffler 110 can be changed, adjusted, or otherwise manipulated. In other cases, the inlet muffler 110 can be fixed relative to the air inlet port 106.

[0038] In one or more embodiments, the air inlet port 106 can be arranged within the boundary defined by the power tool 102, for example, within the power tool 102. In one or more embodiments, the air inlet port 106 can be arranged outside the boundary defined by the power tool 102. In other cases, the air inlet port 106 can be arranged at or adjacent to the boundary defined by the power tool 102. The inlet muffler 110 can be coupled to the air inlet port 106 via one or more intermediate passages 112, channels and / or ports. The airflow 114 passing through the inlet muffler 110 can pass through the air inlet port 106, via the aperture 108, to the noise generating element 104. In some embodiments, the airflow 114 can provide oxygen to the internal combustion engine. In other embodiments, the airflow 114 can be compressed or otherwise biased (e.g., by means of fan blades or impellers) in the power tool. In other embodiments, the airflow 114 can provide oxygen to the internal combustion engine or one or more similar components, and can also provide air for compression or biasing.

[0039] The power tool 102 may define a first sound intensity dB1 on the upstream side of the inlet muffler 110 near the exterior of the power tool 102, and define a second sound intensity dB2 on the downstream side of the inlet muffler 110, which is different from dB1. In one embodiment, dB1 is at least 1 dB smaller than dB2, such as at least 10 dB smaller than dB2, such as at least 20 dB smaller than dB2. In this way, the noise emitted by the noise generating element 104 can be damped from the external environment.

[0040] In one embodiment, the power tool 102 may limit the non-muffler intensity dB measured when the power tool 102 is not equipped with the inlet muffler 110. U And the muffler intensity dB measured when the power tool 102 is equipped with the inlet muffler 110 M , dB M Less than dB U In some cases, dB M Can be compared to dB U At least 0.1dB smaller, for example, U At least 0.5dB smaller, for example, U At least 1dB smaller, for example, U At least 1.5dB smaller, for example, U At least 2dB smaller, for example, U At least 3dB smaller, for example, U At least 4dB smaller, for example, U At least 5dB smaller, for example, U At least 7.5dB smaller, for example, U In one embodiment, the noise reduction ratio of the power tool 102 is [dB M / dB U ] can be less than 0.99, for example less than 0.98, for example less than 0.97, for example less than 0.96, for example less than 0.95, for example less than 0.9, for example less than 0.8.

[0041] In one embodiment, the power tool 102 may define an unmuffled operating power capacity P measured when the power tool 102 is not equipped with an inlet muffler 110. U And the muffler operating power capacity P measured when the power tool is equipped with an inlet muffler M , where P M Not less than 0.85P U , for example, not less than 0.9P U , for example, not less than 0.91P U , for example, not less than 0.92P U , for example, not less than 0.93P U , for example, not less than 0.94PU , for example, not less than 0.95P U , for example, not less than 0.96P U , for example, not less than 0.97P U , for example, not less than 0.98P U , for example, not less than 0.99P U In one embodiment, P M can be approximately equal to P U In this manner, by using the inlet muffler 110 to dampen the acoustic intensity of the power tool 102 , the operating power capacity of the power tool 102 may not be substantially affected.

[0042] In one embodiment, the power tool 102 may define an operating power to damping loss ratio At least 1.25, where dB M is the noise reduction intensity of the power tool 102 when equipped with the inlet muffler 110, dB U is the non-muffled intensity of the power tool 102 when not equipped with the inlet muffler 110, P M is the maximum muffler operating power capacity of the power tool 102 when equipped with the inlet muffler 110, and P U is the non-muffled operating power capacity of the power tool 102 when not equipped with the inlet muffler 110. In a more particular embodiment, the operating power to damping loss ratio can be at least 1.3, such as at least 1.35, such as at least 1.4, such as at least 1.45, such as at least 1.5, such as at least 1.55, such as at least 1.6, such as at least 1.65, such as at least 1.7, such as at least 1.75, such as at least 1.8, such as at least 1.85, such as at least 1.9, such as at least 1.95, such as at least 2, such as at least 2.5, such as at least 3, such as at least 3.5, such as at least 4.

[0043] A power tool 102 having a high operating power to damping loss ratio can exhibit noise reduction without the corresponding power loss typical of conventional noise reduction techniques. While conventional noise reduction techniques generally restrict airflow, thereby reducing operating power capacity, noise reduction techniques according to embodiments described herein minimize the impact on operating power capacity.

[0044] In one embodiment, the inlet muffler 110 may limit the airflow ratio The cross-sectional area AF through which the airflow of the inlet muffler 110 can pass without restriction is P Relative to the total cross-sectional area AF of the inlet muffler 110 T The ratio of is measured, The use of a high airflow ratio can reduce the power loss of the power tool 102, thereby reducing the performance loss caused by reducing noise.

[0045] In the exemplary embodiment described below, the power tool 102 is a blower 10 . Figures 2 to 17 Specific aspects of the blower 10 are directed to one or more embodiments of the present disclosure. However, any features described with respect to the blower 10 may be implemented in embodiments with respect to other power tools 102 described below (e.g., lawn mowers, compressors, aerators, forced air heaters, pumps, fluid pumps, generators, snow blowers, pressure washers, chainsaws, edgers, trimmers, vacuum machines, etc.).

[0046] Reference now Figures 2 to 17 , an embodiment of a blower 10 according to the present disclosure is provided. The blower 10 according to the present disclosure advantageously includes improved noise reduction features while also maintaining or having improved performance features. For example, in some exemplary embodiments, the blower 10 according to the present disclosure produces a flow rate of at least 500 CFM (e.g., at least 550 CFM) at a speed of 125 miles per hour (mph) while keeping the sound at or below 70 dB(A) (e.g., at or below 60 dB(A)) at 50 feet (i.e., using the ANSI 50-foot test, ANSI / OPEI B175.2-2012 (amendment published on December 30, 2013, and / or ISO 22868, second edition 2011-03-01)). In an exemplary embodiment, the blower 10 according to the present disclosure is a battery-powered handheld blower 10. In an exemplary embodiment, the battery is a 40-volt (nominal) battery. Blower 10 may be configured to receive batteries of various sizes, shapes, and / or power capacities.

[0047] A blower 10 according to the present disclosure may include a body 12. A handle 14 may be connected to and extend from the body 12. A trigger 16 may be included in the handle 14. The trigger 16 is operable to cause operation of the blower 10 by activating and deactivating the motor 58 of the blower 10. The trigger 16 may include a variable speed selection function, thereby allowing an operator to variably control the power of the blower 10 within a preset speed range.

[0048] The battery 18 can be removably connected to the blower 10 to power the blower 10, particularly its motor 58. The body 12 can define a battery mounting seat 20, and the battery 18 can be removably connected to the battery mounting seat 20. When connected in and connected to the battery mounting seat 20, the battery 18 can provide a power source for the blower 10, particularly its motor 58. For example, the battery mounting seat 20 can provide an electrical connection between the battery 18 and the motor 58.

[0049] The body 12 may define an airflow path 22 therethrough. The airflow path 22 may extend between and define an inlet end 24 and an outlet end 26 of the body 12. When the blower 10 is operated as a blower, airflow along the airflow path 22 may flow into the body 12 via the inlet end 24 and be discharged from the body 12 via the outlet end 26. In one or more embodiments, the outlet end 26 of the body may be angularly offset from the airflow path 22 by an angle α. F , which is measured between a plane P1 oriented orthogonal to the airflow path 22 and a plane P2 defined by the outlet end 26. In one embodiment, α F It may be at least 1°, such as at least 2°, such as at least 3°, such as at least 5°, such as at least 10°, such as at least 20°.

[0050] The body 12 may include stabilizing elements 84 and 86 disposed on the bottom to prevent the blower 10 from tipping over or rolling when resting on the ground. In one embodiment, at least one of the stabilizing elements 84 and 86 may define an opening (e.g., opening 88) to allow an operator to store the blower 10 on a member (e.g., a hook).

[0051] The body 12 may include an inlet portion 30, which may include and define the inlet end 24; and may include an outlet portion 32, which may include the outlet end 26. In one or more embodiments, the inlet portion 30 may be removably coupled to the outlet portion 32. For example, in some embodiments, the inlet portion 30 may be threadedly coupled to the outlet portion 32. In some embodiments, the inlet portion 30 may be coupled to the outlet portion 32, for example, by a non-threaded engagement (e.g., a bayonet connection, such as one or more pins, buckles, rotatable rods, latches (e.g., Fig. 8A and 8B800) or any combination thereof). The latch 800 can be attached to the entrance portion 30, the outlet portion 32, or both, and selectively secures the entrance portion 30 and the outlet portion 32 together. In the illustrated embodiment, the latch 800 is a pivotable latch pivotally coupled to the entrance portion 30. The latch 800 may include a pivotable body 802 having an engagement member (not shown) configured to engage with a mating member 804 on the outlet portion 32. In some cases, the pivotable body 802 of the latch 800 may be pivotally coupled to the outlet portion 32 and engageable with the mating member 804 on the entrance portion 30. In one embodiment, the latch 800 may be spring biased to a locked configuration to facilitate connection. For example, the attachment of the entrance portion 30 and the outlet portion 32 may be performed by aligning the portions 30 and 32 and applying a combined force therebetween. Latch 800 can automatically receive the mating component and removably couple parts 30 and 32 together. In another embodiment, the latch can be substantially free of a spring biasing member. Latch 800 can be disposed on the side of blower 10, the top of blower 10, the bottom of blower 10, or anywhere in between.

[0052] In one or more embodiments, the blower 10 may include a single latch 800. In other embodiments, the blower 10 may include a plurality of latches 800, such as at least two latches 800, at least three latches 800, or at least four latches 800. In one embodiment, the plurality of latches 800 may include latches of the same or similar type. In another embodiment, at least two of the plurality of latches 800 may include latches of different types, or may be operably coupled to different components of the blower 10, such as one latch 800 may be pivotally coupled to the inlet portion 30 and one latch 800 may be pivotally coupled to the outlet portion 32.

[0053] As discussed herein, the inlet portion 30 can house the fan assembly 50. The outlet portion 32 can be downstream of the fan assembly 50 in the direction of the airflow path 22. In one embodiment, a technician can access the fan assembly 50 or other components of the blower 10 by removing the outlet portion 32 from the inlet portion 30 using the latch 800 described above.

[0054] A longitudinal axis 11 may be defined for the blower 10. In some embodiments, as Figure 2 3, both the inlet portion 30 and the outlet portion 32 may extend along (eg, linearly and coaxially) the longitudinal axis 11. In other embodiments, such as Figure 6As shown, the outlet portion 32 may extend along (e.g., linearly and coaxially) the longitudinal axis 11, while at least a portion of the inlet portion 30 extends in a direction other than linearly along the longitudinal axis 11. For example, the inlet portion 30 may include a curvilinear portion 34 that extends along a curvilinear path relative to the longitudinal axis 11. In some embodiments, the curvilinear portion 34 may be connected to the outlet portion 32, while in other embodiments, a linear portion 38 of the inlet portion 30 that extends (e.g., linearly and coaxially) along the longitudinal axis 11 is disposed between and connects the curvilinear portion 34 and the outlet portion 32.

[0055] In some embodiments, the curved portion 34 may include a first portion 35 bent in a first direction and a second portion 36 bent in a second opposite direction. Thus, in these embodiments, the curved portion 34 may have an S-shape.

[0056] In some embodiments, Figure 2 3, the plane defined by the inlet end 24 is perpendicular to the longitudinal axis 11. In other embodiments, such as Figure 5 As shown, the plane defined by the inlet end 24 is at an angle 25 with respect to the vertical longitudinal axis 11. For example, the angle 25 can be between 70 and 110 degrees, such as between 80 and 100 degrees, such as between 85 and 95 degrees. In the exemplary embodiment as shown, the inlet end 24 can be, for example, away from the handle 14 and can face the ground when the user holds the blower 10 in the operable position.

[0057] Now special reference Figure 3A , a blower 10 according to the present disclosure may include an inlet muffler 40 disposed at the inlet end 24. The inlet muffler 40 may be connected to the body 12, and the airflow path 22 may be defined by the inlet muffler 40. In one embodiment, the inlet muffler 40 may be removably connected to the body 12. The inlet muffler 40 may be replaced between various designs having different performance characteristics and properties.

[0058] The inlet muffler 40 may advantageously include a plurality of inlet ports 42. Each inlet port 42 may be separate from the other inlet ports in the plurality of inlet ports 42. In some exemplary embodiments, the plurality of inlet ports 42 may be aligned substantially parallel to one another, for example, the plurality of inlet ports 42 may be arranged along a single plane. In other embodiments, one or more inlet ports 42 may be aligned in a non-parallel manner relative to the other inlet ports 42. Each of the plurality of inlet ports 42 may include an outer peripheral surface 44 defining a port aperture 46 through which the airflow path 22 is defined. Thus, the airflow path 22 may be defined by the plurality of inlet ports 42.

[0059] Using multiple inlet ports 42, rather than a single inlet port, advantageously allows the overall length of the muffler 40 to be significantly reduced, for example, to one-half to one-third the length. In an exemplary embodiment, the multiple inlet ports 42 may include, for example, four to ten inlet ports 42, such as five to nine inlet ports 42, such as six to eight inlet ports 42, such as seven inlet ports 42, or consist of these inlet ports 42.

[0060] In one or more embodiments, at least one of the plurality of inlet ports 42 may define a polygonal cross-sectional shape. Figure 3A In the exemplary embodiment shown, each of the plurality of inlet ports 42 has a hexagonal cross-sectional shape. In an exemplary embodiment, the plurality of inlet ports 42 may include a central inlet port 42C surrounded by a plurality of peripheral ports 42 (e.g., a layer of six peripheral ports 42). In one or more embodiments, the volumetric airflow passing through the inlet ports 42 may be substantially equal between different inlet ports 42. In other embodiments, the inlet ports 42 may receive different amounts of volumetric airflow passing therethrough. For example, the central inlet port 42C may receive a lower volumetric airflow rate than each of the six peripheral ports 42.

[0061] refer to Fig. 9A and Fig. 9B In another exemplary embodiment, the plurality of inlet ports 42 may have a curved cross-sectional shape defined by the outer peripheral surface 44. The curved cross-sectional shape may include a circular cross-sectional shape ( Fig. 9A ), oval cross section ( Fig. 9B ) or other elongated, non-polygonal cross-sectional shapes. The oval cross-sectional shape can define an aspect ratio [D MAX / D MIN ], the aspect ratio is given by the maximum dimension D of the shape MAX Relative to the minimum dimension D of the shape MINThe aspect ratio [D MAX / D MIN ] may be no greater than 100.0, for example no greater than 50.0, for example no greater than 10.0.

[0062] In one embodiment, the inlet muffler 40 may define a central inlet port 42C having one or more different properties than the surrounding inlet ports 42 (see, for example, Fig. 9B ). For example, the central inlet port 42C may have a different size than the surrounding inlet ports 42, a different shape than the surrounding inlet ports 42, a different angular orientation than the surrounding inlet ports 42, or any combination thereof.

[0063] In one embodiment, the peripheral inlet ports 42 may be arranged along an arc extending equidistantly about a center point of the inlet muffler 40 (eg, Fig. 9A That is, each of the peripheral inlet ports 42 may be equidistant from the center point of the inlet muffler 40. In another embodiment, the peripheral inlet ports 42 may be arranged along an oval or otherwise elongated arc extending around the center point of the inlet muffler 40 (e.g., Fig. 9B The non-circular arc of the peripheral inlet port 42 may directionally alter the airflow along the airflow path 22 , for example, causing more air to be drawn into the inlet muffler 40 from a desired location along the airflow path 22 .

[0064] Fig. 9C Still another embodiment of an inlet muffler 40 is shown including an inlet port 42 having a rectangular cross-sectional shape. More particularly, Fig. 9C Square inlet ports 42 are shown arranged in a grid pattern. Although only five square inlet ports 42 are shown, in other embodiments, the grid can include at least six inlet ports 42, such as at least seven inlet ports 42, such as at least eight inlet ports 42, and so on. In one embodiment, the peripheral surfaces 44 of the polygonal (e.g., square) inlet ports 42 can define an arcuate interface, wherein the peripheral surfaces 44 are connected together at the arcuate interface. In another embodiment, the peripheral surfaces 44 can define a linear connection, such as Fig. 9C The 90° interface shown in .

[0065] In one embodiment, the inlet muffler 40 may limit the airflow ratio The cross-sectional area AF through which the airflow can pass unrestricted is P Relative to the total cross-sectional area AF of the inlet muffler 40T The airflow ratio is measured by the ratio of, for example, not less than 0.8, for example, not less than 0.85, for example, not less than 0.9, for example, not less than 0.95, for example, not less than 0.97, for example, not less than 0.99.

[0066] In one embodiment, the heights of the outer peripheral surfaces 44 of adjacent inlet ports 42 measured parallel to the longitudinal axis 11 may be different. Fig. 9C The central inlet port 42C may define a first height H C , the first height H C A second height H of one or more surrounding inlet ports 42 S In one embodiment, H C Can be greater than H S For example, H C Can be at least 101% H S , for example at least 105% H S , for example at least 110% H S , for example at least 120% H S , for example at least 150% H S In another embodiment, H C Can be less than 99% H S , for example less than 95% H S , for example less than 90% H S , for example less than 80% H S , for example less than 50% H S In one or more embodiments, the height of the inlet port 42 may be gradually changed, for example, Fig. 9C In other embodiments, the inlet port 42 may include a castellated trailing surface defined by a non-gradual change in height.

[0067] Reference again Fig. 9AIn one or more embodiments, the inlet muffler 40 may include one or more secondary inlet ports 42S. In one embodiment, the secondary inlet ports 42S may be defined as openings radially arranged between the central inlet port 42C and the surrounding inlet ports 42. The secondary inlet ports 42S may have different characteristics compared to the central inlet port 42C, the surrounding inlet ports 42, or both. For example, the secondary inlet port 42S may be smaller than the surrounding inlet ports 42. The secondary inlet ports 42S may produce a desired airflow pattern within the blower 10. For example, the airflow path through the secondary inlet port 42S may be angularly offset from the inlet ports 42 and 42C. The angularly offset flow path may enhance air mixing within the blower 10 and / or produce a pre-swirl of air entering the inlet muffler 40.

[0068] In some cases, at least one inlet port 42 may be inclined relative to the longitudinal axis 11 of the blower 10. For example, Fig.10 1 shows a schematic cross-sectional view of the inlet muffler 40. In one or more embodiments, the outer peripheral surface 44A of the angled inlet port 42A of the inlet muffler 40 can be inclined relative to the longitudinal axis 11 of the blower 10. Air drawn into the blower 10 through the inlet muffler 40 can travel along the modified airflow path 22M created by the angled inlet port 42A. Therefore, the air passing through the inlet muffler 40 can be angularly offset by an angle α compared to the air entering the same inlet muffler 40 having a non-angled inlet port 42. A In some cases, the airflow path 22M may be slightly straightened after passing through the inlet muffler 40 due to the negative pressure caused by the rotor blades associated with the rotary motor in the longitudinal downstream direction, that is, from the angle α A It slightly follows the longitudinal axis 11 of the blower 10 .

[0069] In one embodiment, the angle of the modified airflow path 22M is offset by α A The extent of the inlet port 42A may be determined at least in part by the angular displacement α of the inlet port 42A relative to the longitudinal axis 11. D In one embodiment, the angular displacement α of the oblique inlet port 42A is D It may be at least 1°, such as at least 2°, such as at least 3°, such as at least 4°, such as at least 5°, such as at least 10°, such as at least 25°, such as at least 45°, such as at least 60°. Although a straight peripheral surface 44A is shown, in another embodiment, the peripheral surface 44A of at least one oblique inlet port 42A may be arcuate, polygonal, or include arcuate and linear portions when viewed in cross section. In addition, at least two peripheral surfaces 44A may define different angular displacements α compared to each other. D, thereby creating multiple unique modified airflow paths 22M.

[0070] In one embodiment, the angular displacement α of the oblique inlet port 42A is D That is, the angular displacement of the oblique inlet port 42A can be set to a non-adjustable angle relative to the longitudinal axis 11. In another embodiment, the angular displacement α of the oblique inlet port 42A is D For example, the blower 10 may include an operable interface (not shown) configured to allow an operator to selectively adjust the angular displacement α of the angled inlet port 42A. D Using the operable interface, the operator can, for example, reduce the angular displacement α of the oblique inlet port 42A. D , or increase the angular displacement α of the oblique inlet port 42A D The operable interface may be configured to be selectively lockable to maintain the angled inlet port 42A at a desired angular displacement α D .

[0071] The angled inlet port 42A may be adapted to generate a pre-swirl in the blower 10. That is, the airflow entering the blower 10 through the angled inlet port 42A of the inlet muffler 40 may be angularly offset relative to the longitudinal axis 11, thereby generating a rotating air pattern in the blower 10 before passing through the motor 58 or rotor blades associated therewith. In one embodiment, the pre-swirl airflow condition may define a direction of rotation through the blower 10 that is the same as the direction of rotation caused by the rotation of the downstream rotor blades. Using the pre-swirl airflow condition may enhance noise reduction while maintaining the performance of the blower 10 by reducing choppiness at the rotor blades.

[0072] Reference again Figure 3A , a damper material 48 may be disposed on the peripheral surface 44 of each of the plurality of inlet ports 42 (e.g., substantially the entire periphery of the peripheral surface 44 of each of the plurality of inlet ports 42). As shown, the damper material 48 may further define a port aperture 46 extending therethrough. Thus, the damper material 48 may further define the airflow path 22. The damper material 48 may be formed of a suitable damping material, such as, in an exemplary embodiment, a foam or a fiber-based composite material or other material, such as a composite material or other material based on glass fiber or natural fiber (such as jute). In an exemplary embodiment, the damping material may be an open-cell material, such as an open-cell foam. For example, the damping material 48 may be formed of a polyurethane foam, such as, in an exemplary embodiment, an open-cell polyurethane foam. In an exemplary embodiment, each damping material 48 may have a thickness 47 between 6 mm and 10 mm, such as a thickness between 7 mm and 9 mm, such as a thickness of 8 mm.

[0073] Figure 3B An exemplary frame 90 is shown disposed within the damper material 48. Figure 3C As shown, the frame 90 can generally include a body 96 extending between a first axial end 92 and a second axial end 94. At least one of the first axial end 92 and the second axial end 94 can define a tapered profile (e.g., a flared opening) to facilitate airflow therethrough. The frame 90 can include one or more openings 98, such as a plurality of openings 98. The openings 98 can be arranged along the body 96 and expose the damper material 48 to air passing through the air inlet port 42. In one embodiment, the body 96 can include at least ten openings 98, such as at least twenty openings 98, such as at least fifty openings 98. In one embodiment, the openings 98 can extend along the body 96 in one or more rows and / or one or more columns. In one embodiment, the openings 98 can define a damper material exposure ratio [A O / SA B ], which passes through the combined area A of all openings 98 of the frame 90 O Relative to the surface area SA of the main body 96 B Measured by the damper material exposure ratio, the exposure ratio is at least 0.05, such as at least 0.1, such as at least 0.25, such as at least 0.5, such as at least 0.75, such as at least 1.0, such as at least 1.25, such as at least 1.5. A relatively high damper material exposure ratio can reduce noise from the blower 10, while a relatively low damper material exposure ratio can extend the effective operating life of the damper material 48. In one embodiment, the damper material exposure ratio is in a range between 0.5 and 1.25, such as in a range between 0.75 and 1.1.

[0074] In one embodiment, the frame 90 may also include a retaining structure 100 configured to engage with the damper material 48. The retaining structure 100 may include, for example, a clip, a threaded fastener, a non-threaded fastener, a button fastener, a hook, one or more Molly bolts, a hook and loop engagement, or other known attachment protocols. In one embodiment, the frame 90 may be removably attached to the damper material 48. In this manner, an operator may selectively replace the damper material 48, for example, in the event that the damper material 48 becomes dirty or contaminated during use.

[0075] In some cases, the outer surface of the body 96 can define a shape that is generally similar to the inner shape of the damper material 48. In the illustrated embodiment, the frame 90 defines a generally hexagonal shape. In another embodiment, the frame 90 can define a curved shape or have a shape corresponding to a different polygonal arrangement. In one embodiment, the damper material 48 can have a split 102 to allow it to be installed on the frame 90. For example, referring to Figure 3B , the split 102 can extend axially between the first axial end 92 and the second axial end 94. During installation, the damper material 48 can be expanded so that the frame 90 passes through the split 102. After installation, the split 102 can be connected, for example, its circumferential ends can be fixed together, or remain open. In a non-illustrated embodiment, the frame 90 can be installed in the damper material 48 by axially translating the frame 90 through the opening of the damper material 48.

[0076] refer to Fig.11 In one or more embodiments, the inlet muffler 40 may define one or more auxiliary openings 1100 through a side surface 1102 of the inlet muffler 40. In a non-illustrated embodiment, at least one opening 1100 may be a portion of the body 12. For example, the inlet muffler 40 may include at least one opening 1100, such as at least two openings 1100, such as at least five openings 1100, such as at least ten openings 1100. In one embodiment, the openings 1100 may be equally spaced from each other around the circumference of the inlet muffler 40. In another embodiment, the openings 1100 may be closely stacked together at one location and spaced further apart at another location. For example, the openings 1100 may be closely stacked together at the top side of the blower 10 and spaced further apart from each other at the bottom side of the blower 10. The openings 1100 may define an airflow path that is generally orthogonal to the airflow path 22 previously described in the blower 10. In normal use, the opening 1100 can work with the air inlet 42 to allow air to enter the inlet portion 30 of the blower. When one or more of the inlet ports 42 become restricted (e.g., when a leaf or other debris is stuck on the inlet muffler 40), the opening 1100 can advantageously allow air to enter the inlet portion 30. Traditionally, such restrictions increase motor noise, however, including the opening 1100 can allow the motor to operate at a more ideal power level even when restrictions occur along the inlet muffler 40.

[0077] In one or more embodiments, one or more openings 1100 may all have the same shape, size, or both. In other embodiments, at least two openings 1100 may be different from each other, for example, having different sizes, shapes, or both. For example, at least one of the openings 1100 may have an arc shape (e.g., circular or oval) or a polygonal shape (e.g., rectangular or pentagonal).

[0078] In a non-illustrated embodiment, the blower 10 may further include an adjustable interface configured to selectively restrict the airflow path through at least one of the one or more openings 1100. The adjustable interface may include, for example, a rotatable or translatable sleeve disposed around the inlet muffler 40 and configured to selectively restrict the airflow through the opening 1100. An operator may adjust the angle or linear displacement of the sleeve to selectively adjust the airflow through the opening 1100. In certain non-limiting embodiments, the sleeve may be part of the inlet muffler 40.

[0079] In accordance with the present disclosure, the inlet muffler 40 advantageously provides significant noise reduction for the blower 10. This noise reduction is advantageously provided while maintaining the performance of the blower 10. Furthermore, such an inlet muffler 40 is relatively short in length and uses a relatively thin damper material 48 while providing such advantageous noise reduction.

[0080] Reference now Figure 4 and Figure 5 According to the present disclosure, various components that advantageously provide noise reduction in the blower 10 may be disposed within the body 12. For example, a fan assembly 50 may be disposed within the body 12, such as in the inlet portion 30 thereof. The fan assembly 50 may include an axial flow fan 52 including a hub 54 and a plurality of rotor blades 56 extending radially outward from the hub 54.

[0081] Fig.12A front view of an axial flow fan 52 as seen from an upstream position according to one or more embodiments of the present invention is shown. As shown, rotor blades 56 extend radially outward from the hub 54. During normal operation, the hub 54 is configured to rotate in the direction indicated by arrow 1200. In this regard, each rotor blade 56 can define a leading edge 1202 and a trailing edge 1204 relative to the rotation angle. In one embodiment, when viewed along the longitudinal axis 11 of the blower 10, at least a portion of at least one of the leading edge 1202 and the trailing edge 1204 can have a linear (i.e., straight) profile. In another embodiment, at least a portion of at least one of the leading edge 1202 and the trailing edge 1204 can have a curved profile. In the illustrated embodiment, both the leading edge 1202 and the trailing edge 1204 are swept forward. That is, the leading edge 1202 and the trailing edge 1204 are angularly offset from a line 1206 extending radially from a center point 1208 of the axial flow fan 52. In another embodiment, only one of the leading edge 1202 and the trailing edge 1204 of the at least one rotor blade 56 is swept forward. In yet another embodiment, neither the leading edge 1202 nor the trailing edge 1204 of the at least one rotor blade 56 is swept forward. For example, at least one of the leading edge 1202 and the trailing edge 1204 of the at least one rotor blade 56 may be swept backward or disposed generally along a line 1206 extending radially from a center point 1208.

[0082] The rotor blades 56 may be angled relative to the airflow path 22 to create a positive pressure on the downstream side of the axial flow fan 52 and a corresponding negative pressure on the upstream side thereof. Fig.13 , rotor blades 56 can be angled relative to the longitudinal axis 11 of the blower 10. For example, one of the rotor blades 56 can define a cross-sectional shape having a best fit line 1300 that is angularly offset from the longitudinal axis 11 of the blower by an angle of attack AOA. The angle of attack of the rotor blades 56 can dictate the positive and negative pressures generated by the axial flow fan 52 at operating speeds. For example, the angle of attack of at least one rotor blade 56 can be between 1° and 89°, such as between 20° and 70°.

[0083] In one embodiment, at least two rotor blades 56 may define different angles of attack. For example, the first rotor blade 56A may define a first angle of attack AOA1, and the second rotor blade 56B may define a second angle of attack AOA2 different from AOA1. For example, AOA1 may be greater than AOA2. For example, AOA1 may be 1.01AOA2, for example, 1.02AOA2, for example, 1.05AOA2, for example, 1.1AOA2, for example, 1.2AOA2, for example, 1.3AOA2, for example, 1.5AOA2. In one embodiment, the angles of attack of adjacent rotor blades 56 may be different from each other. For example, the rotor blades 56 may have alternating angles of attack, gradually staggered angles of attack, random angles of attack, or any other possible variation. Without wishing to be bound by a particular theory, it is believed that changing the angle of attack of at least one of the rotor blades 56 relative to the other rotor blades 56 on the axial fan 52 may enhance noise reduction without sacrificing the power of the blower 10.

[0084] Fig.18 An embodiment of a rotor blade 56 is shown that includes serrations 1800 disposed on an edge 1802 of the rotor blade 56. In one or more embodiments, the serrations 1800 may be disposed on a leading edge 1804 of at least one rotor blade 56. In one or more embodiments, the serrations 1800 may be disposed on a radially outer edge 1806 of at least one rotor blade 56. In one or more embodiments, the serrations 1800 may be disposed on a trailing edge 1808 of at least one rotor blade 56. In one embodiment, the serrations 1800 may be disposed on any combination of the leading edge 1804, the radially outer edge 1806, and the trailing edge 1808.

[0085] In one embodiment, the serrations 1800 may all define the same, or substantially similar, shape and / or depth into the rotor blade 56. In another embodiment, at least two of the serrations 1800 may have different characteristics than one another, such as having different shapes and / or depths than one another. For example, the serrations on the leading edge 1804 of the first rotor blade 1810a may be different from the serrations on the leading edge 1804 of the second rotor blade 1810b. In another exemplary embodiment, the serrations on the leading edge 1804 of the first rotor blade 1810a may be different from the serrations on the radially outer edge 1806 of the first rotor blade 1810a.

[0086] The shape of the sawtooth 1800 can be designed to reduce the noise of the axial fan 52 without sacrificing the power of the blower 10. The sawtooth 1800 may include a curved portion, a polygonal portion, or any combination thereof. In some cases, the sawtooth 1800 may have a beveled side or a multi-beveled side that tapers between the axially opposite ends of the axial fan 52. In other cases, the sawtooth 1800 may have a straight side surface or other non-beveled side surface. In one embodiment, the sawtooth 1800 may have a rounded corner. In other embodiments, the sawtooth 1800 may have an angled corner.

[0087] Reference again Figure 5 The fan assembly 50 may also include a motor 58 that is rotatably connected to the axial flow fan 52 and that can cause the axial flow fan 52 to rotate due to its operation. For example, a shaft 60 may rotatably couple the motor 58 to the axial flow fan 52, such as to the hub 54 of the axial flow fan 52. The rotation of the motor 58 may cause the rotation of the shaft 60, thereby causing the rotation of the axial flow fan 52.

[0088] The shaft 60 and the axial fan 52 can be positioned on the upstream side of the motor 58 along the airflow path 22. In addition, in some embodiments, the secondary fan 62 (which can be an axial fan having a hub and a plurality of rotor blades extending radially from the hub) and the secondary shaft 64 (which can be integral with the shaft 60) can be positioned on the downstream side of the motor 58. The motor 58 can be operably coupled to the secondary fan 62 and can cause the secondary fan 62 to rotate due to its operation. The secondary shaft 64 can rotatably couple the motor 58 to the secondary fan 62, such as to the hub of the secondary fan 62. The rotation of the motor 58 can cause the rotation of the secondary shaft 64, thereby causing the rotation of the secondary fan 62. The secondary fan 62 can include any one or more of the features previously described with respect to the axial fan 52.

[0089] In an exemplary embodiment, the motor 58 may be a brushless DC motor. Additionally, in an exemplary embodiment, the motor 58 may be an externally-inverted DC motor. Such an externally-inverted motor may be particularly advantageous because it can provide relatively high torque for a given motor diameter compared to an internally-inverted motor.

[0090] The fan assembly 50 can further include a motor housing 66 that can generally surround and house the motor 58. The motor housing 66 can further surround and house the secondary shaft 64 and the secondary fan 62. The shaft 60 can extend from the motor housing 66, and the fan 52 can be external to the motor housing 66. Thus, the motor housing 66 can be downstream of the fan 52 along the airflow path 22. In an exemplary embodiment, at least a portion (e.g., a downstream portion) of the motor housing 66 is generally conical, and thus the diameter gradually decreases along the airflow path 22.

[0091] A plurality of stator blades 70 may extend, such as generally radially, from the motor housing 66. Thus, the stator blades 70 may be downstream of the fan 52 along the airflow path 22. In an exemplary embodiment, the plurality of stator blades 70 may include or consist of four to twelve stator blades 70, such as six to eleven stator blades 70, such as eight to ten stator blades 70, such as nine stator blades 70. Using a relatively large number of stator blades 70 advantageously increases an initial resonant frequency associated with the stator blades 70, thereby providing a resonant frequency that may be more easily muffled using the noise reduction features discussed herein.

[0092] In an exemplary embodiment, the downstream or trailing edge 72 of the stator vane 70 may include a noise reduction feature 74. As shown, such a noise reduction feature 74 may be a structure attached to the trailing edge 72 or a shape defined in the trailing edge 72. For example, in an exemplary embodiment, such a noise reduction feature 74 is a V-shape defined in the trailing edge 72. The noise reduction feature 74 according to the present disclosure advantageously provides further noise reduction for the blower 10 according to the present disclosure.

[0093] The fan assembly 50 may also include an outer casing 76. The outer casing 76 may surround the fan 52 and the motor 58, and may further surround the secondary fan 62. The outer casing 76 may further surround the stator blades 70, and the stator blades 70 may extend between and be connected to the motor housing 66 and the outer casing 76. The outer casing 76 may further surround at least a portion of the motor housing 66, such as an upstream portion thereof relative to the airflow path 22. In some embodiments, a downstream portion of the motor housing 66 relative to the airflow path 22 may extend from the outer casing 76.

[0094] In some embodiments, the outer housing 76 can include a bellmouth inlet 77 on its upstream end in the airflow path 22. The bellmouth inlet 77 can facilitate airflow into and through the fan assembly 50.

[0095] In an exemplary embodiment, a plurality of bushings 78 may be provided. Each bushing 78 may be arranged to contact between the outer housing 76 and the main body 12 (e.g., the inlet portion 30 thereof). Thus, each bushing 78 may be radially outside the outer housing 76. In an exemplary embodiment, the bushing 78 may be formed of a suitable elastic material (e.g., rubber). The bushing 78 may support the outer housing 76 within and relative to the main body 12, and may advantageously reduce noise associated with the fan assembly 50 (e.g., noise caused by vibration of the outer housing 76 and other components of the fan assembly 50 during operation of the blower 10).

[0096] Fig.17 An embodiment of a blower 10 is shown that includes a damping element 1700 disposed between an outer housing 76 and a bell mouth (not shown). The damping element 1700 can be disposed in a slot 1702 of the outer housing 76. The damping element 1700 can include a foam, such as a closed cell foam. The damping element 1700 can be formed of a material having a higher density than the damper material 48 previously described. In one embodiment, the damping element 1700 can reduce vibration noise along the outer housing 76, thereby reducing audible noise from the blower 10.

[0097] Reference now Fig.14 In one or more embodiments, the blower 10 may further include a stator 1400 upstream of the axial flow fan 52. The stator 1400 may form a pre-swirl of air in the inlet portion 30 in front of the axial flow fan 52. The air entering through the inlet muffler 40 may pass through the stator 1400, wherein the air becomes a rotating vortex when entering the area associated with the rotor blades 56 of the axial flow fan 52. In one embodiment, the stator 1400 may include a plurality of blades 1402, which are configured to swirl the air rotationally in the pre-swirl path. The rotating pre-swirl may allow the axial flow fan 52 to operate at a lower noise level while producing the same output power. In one embodiment, the stator 1400 may be attached to the bell mouth inlet 77 or a portion of the bell mouth inlet. For example, the stator 1400 may be snap-fitted, fastened or otherwise connected to the bell mouth inlet 77 or formed integrally therewith. The stator 1400 may be generally disposed upstream of the axial flow fan 52 and downstream of the inlet muffler 40 , and adjusts air flow to improve noise performance.

[0098] In one embodiment, the bellmouth 70 may define one or more surface features 1406 extending into the airflow path 22. The surface features 1406 may include, for example, bumps, ridges, protrusions, vanes, dimples, posts, grooves, surface roughness, textures, three-dimensional markings, funnels, castellations, undulations, other surface features, or any combination thereof. The surface features 1406 may enhance noise reduction, for example by disrupting localized noise generating areas and enhancing airflow through the blower 10.

[0099] Reference now Figure 4 , the blower 10 according to the present disclosure may further include a damper liner 80. The damper liner 80 may be arranged within the body 12, for example relatively close to the outlet end 26 and relatively away from the inlet end 24. For example, the damper liner 80 may be arranged downstream of the outer shell 76 along the airflow path 22. In some embodiments, the damper liner 80 may contact the downstream end of the outer shell 76. In some embodiments, the downstream portion of the motor housing 66 may be surrounded by the damper liner 80. For example, the damper liner 80 may be completely arranged within the outlet portion 32, or may extend between the inlet portion 30 and the outlet portion 32 and within both.

[0100] The damper pad 80 can have a generally cylindrical shape and can contact the body 12. Thus, the damper pad 80 can further define the airflow path 22. The damper pad 80 can be formed of a suitable damping material, such as, in an exemplary embodiment, a foam or a fiber-based composite or other material (e.g., a composite or other material based on glass fiber or natural fibers such as jute). In an exemplary embodiment, the damping material can be an open-cell material, such as an open-cell foam. For example, the damper pad 80 can be formed of a polyurethane foam, such as, in an exemplary embodiment, an open-cell polyurethane foam shape. In an exemplary embodiment, the damper pad 80 and the damper material 48 are formed of the same damping material.

[0101] In an exemplary embodiment, the damper pad 80 may have a thickness 81 between 6 mm and 10 mm, such as a thickness 81 between 7 mm and 9 mm, such as a thickness 81 of 8 mm.

[0102] In an exemplary embodiment, at least one air gap 82, such as a plurality of air gaps 82, may be defined between the damper pad 80 and the body 12. Each air gap 82 may have a depth 83 (in the radial direction) between 2 mm and 8 mm, such as a depth between 3 mm and 7 mm, such as a depth between 4 mm and 6 mm, such as a depth of 5 mm. Each air gap 82 may extend circumferentially between the damper pad 80 and the body 12, and in an exemplary embodiment, each air gap 82 may be an annular air gap 82 extending throughout the entire circumference. The use of air gaps 82 according to the present disclosure advantageously provides further noise reduction and reduces the thickness 81 required for the damper pad 80 to effectively provide suitable noise reduction.

[0103] Damper pad 80 advantageously provides significant noise reduction for a blower 10 according to the present disclosure. Such noise reduction is advantageously provided while maintaining the performance of blower 10. Furthermore, damper pad 80 may be relatively thin and unobtrusive while providing such advantageous noise reduction.

[0104] Figure 7 An enlarged view of an embodiment of a blower 10 is shown, which includes a handle 140 rotatably coupled to the body 12 of the blower 10. The handle 140 can be rotatable along the pivot 142 in directions 140A and / or 140B. In one embodiment, the handle 140 can be rotated along the pivot 142 by at least 1°, such as at least 5°, such as at least 10°, such as at least 25°, such as at least 45°, such as at least 60°. In another embodiment, the handle 140 can be rotated along the pivot 142 by no more than 360°, such as no more than 180°, such as no more than 90°. By rotatably adjusting the orientation of the handle 140 along the pivot 142, the operator can better align the handle 140 for ergonomic use in multiple operating orientations and positions. In one or more embodiments, the blower 10 can define preset rotatable positions, such as a discrete number of rotatable stop points along the pivot 142, between which the handle 142 can be adjusted. In other embodiments, the handle 140 may be infinitely adjustable, ie, the handle 140 may be stopped at any suitable rotational orientation within the maximum rotatable path of the handle 140 .

[0105] In one embodiment, the handle 140 can be selectively fixed in a desired angular orientation via an optional locking mechanism (e.g., knob 144), which is configured to temporarily fix the handle 140 in a desired angular orientation. For example, the knob 144 may include a wing nut that is connected to or integrally formed with an elongated member extending through the handle 140. Tightening the knob 144 can selectively maintain the handle 140 in a desired angular orientation. In some cases, the knob 144 may include markings indicating the tightening and loosening directions. The knob 144 may include a grippable interface, such as one or more extended surfaces, linings, or other elements to prevent the operator from slipping during tightening or loosening. In one embodiment, when the knob 144 is fully tightened to maintain the handle 140 in a desired angular orientation, the knob 144 or one or more components associated therewith may create a tactile indication for the operator.

[0106] In other embodiments, the optional locking mechanism may include a button fastener, a bayonet connection, a latch or lever, an optional bearing or gear system, one or more pins that can extend into the handle 140, another suitable mechanism known in the art, or any combination thereof. The optional locking mechanism may include one or more locking features to maintain the locking mechanism in a locked configuration, i.e., the handle 140 is selectively fixed in a desired angular orientation.

[0107] In some cases, the blower 10 may be used with batteries 18 of various sizes / shapes that may be received in the battery mount 20 ( Figure 2 ) For larger batteries 18, it may be desirable to rotate the handle 140 in the direction of arrow 140A to increase the space between the battery 18 and the operator's hand. For smaller batteries 18, the operator may rotate the handle 140 forward in the direction of arrow 140B. In one embodiment, different sized batteries 18 may include an indication of the correct angular orientation of the operating handle 140 for operation with the battery 18.

[0108] In one non-illustrated embodiment, handle 140 may be rotatable along a pivot axis other than pivot axis 142. For example, handle 140 may be rotatable along pivot axis 146. Pivot axis 146 may allow an operator to rotate handle 140 along a plane that is parallel or substantially parallel to the length of blower 10.

[0109] refer to Fig.15, the blower 10 may include a leaf scraper 1500 disposed at or adjacent to the outlet end 26. The leaf scraper 1500 may extend from the outlet portion 32 of the blower 10 and provide a surface against which an operator may contact leaves and surface debris that may adhere to the surface and require mechanical contact to be freed. In one embodiment, the leaf scraper 1500 may include a generally planar lip 1502. In a specific embodiment, the lip 1502 may be formed of a relatively rigid material, such as a rigid plastic, metal, or alloy. In another specific embodiment, the lip 1502 may be formed of a relatively flexible material, such as rubber or soft plastic. As used herein, the terms "rigid" and "flexible" are used relative to each other, with the rigid material generally retaining its shape when an operating bias pressure is applied, and the flexible material deforming when an operating bias pressure is applied. In some cases, the rigid lip 1502 may be suitable for applications where an operator wants to scrape off adhered leaves from the ground. In other cases, the flexible lip 1502 may be suitable for applications where the operator wants to access gaps or cracks that cannot be reached by the rigid lip 1502. In one embodiment, the leaf scraper 1500 can be removably attached to the blower 10 so that the operator can swap the lip 1502 for a particular operation. In other embodiments, the leaf scraper 1500 can be adjustable (e.g., rotatable) relative to the outlet portion 32 so that the operator can adjust between two different lips 1502 without removing any lip 1502. In yet another embodiment, the leaf scraper 1500 may include a rigid portion and a flexible portion that are fixedly coupled to the blower 10. The operator can select the rigid lip 1500 and the flexible lip 1500 by rotating the blower 10 accordingly. In one embodiment, the leaf scraper 1500 can prevent the outlet end 26 from contacting the ground (e.g., wet leaves), which may dirty the outlet portion 32.

[0110] Fig.16 A schematic diagram of an exemplary noise cancellation system 1600 that may be utilized with a blower 10 is included. Most of the noise generated by a device (e.g., a blower) occurs within a known range of audible frequencies formed by relatively known tonal signals. The noise in the blower 10 may be associated with the rotor blades 56, the motor 50, and other components that cause resistance and air pressure changes within the blower 10. In order to mitigate and further reduce the noise of the blower 10, the noise cancellation system 1600 may include a microphone 1602 and a sound source 1604, such as a speaker. The noise cancellation system 1600 may further include a controller 1606 configured to control the sound emitted from the sound source 1604 in response to the perceived noise received by the microphone 1602.

[0111] In one embodiment, microphone 1602 comprises a sensitive audio element configured to sense sound and generate an electrical signal representative thereof. Microphone 1602 can be located anywhere on blower 10, but in one particular embodiment is arranged near axial flow fan 52, because most of the noise of blower 10 is caused by axial flow fan 52 and components associated with motor 50.

[0112] Controller 1606 can be configured to receive a representative electrical signal of the noise from microphone 1602. Based on the signal, controller 1606 can generate a second electrical signal indicating the noise cancellation signal. This operation can be performed according to some well-known audio technology. In a specific embodiment, the second electrical signal can be determined, for example, using an adaptive finite impulse response filter.

[0113] In one embodiment, sound source 1604 may be disposed proximate to inlet muffler 40, such as along or adjacent to an inner surface of inlet muffler 40. Sound source 1604 may be configured to generate a sound associated with an audible noise cancellation signal to mitigate noise generated by blower 10. For example, sound source 1604 may generate a signal that is out of phase, such as 180° out of phase, with the noise detected by microphone 1602. The noise cancellation signal may be emitted from blower 10 and mitigate noise levels detected by an operator and nearby persons.

[0114] If further damping of the sound is desired, the noise cancellation system 1600 may further include an error sensor 1608 (e.g., a secondary microphone) configured to detect the sound and generate a third electrical signal representative of the sound detected by the error sensor 1608. The third electrical signal may be communicated to the controller 1606 to further dampen the noise generated by the blower 10.

[0115] FIG. 19A to FIG. 19G 1 and 2 include views of an exemplary power tool including an inlet muffler 40 according to one or more embodiments previously described herein. The exemplary power tool includes a lawn mower 1902 ( Fig.19A )、Chainsaw 1904( Fig.19B ), trimmer 1906( Fig.19C )、Snowblower 1908( Fig.19D )、Generator 1910( Fig.19E )、Pressure Washer 1912( Fig.19F ) and tillage machine 1914( Figure 19G ). Figures 19A to 19G The embodiments shown in are exemplary only. Other power tools may include an inlet muffler 40 according to the embodiments described herein.

[0116] Fig. 20An exemplary flow chart of a damping method 2000 for a power tool is shown. The method 2000 may include a step 2002 of aligning an inlet muffler relative to an air inlet of the power tool. The method 2000 may further include a step 2004 of installing the inlet muffler at the air inlet. The inlet muffler may include a plurality of inlet ports. Each of the plurality of inlet ports may include an outer peripheral surface defining a port aperture extending therethrough. At least one of the plurality of inlet ports may further include a damper material disposed on an outer peripheral surface of at least one inlet port and further defining a port aperture extending therethrough. The installation of the inlet muffler may be performed by coupling the inlet muffler to the air inlet of the power tool. In some cases, the inlet muffler may be permanently coupled to the air inlet. In other cases, the inlet muffler may be temporarily coupled to the air inlet. In this manner, an operator may change, adjust, or otherwise manipulate the inlet muffler.

[0117] In one embodiment, the method 2000 may further include the step of assembling at least one of the plurality of inlet ports before mounting the inlet muffler on the air inlet at step 2004. The step of assembling at least one inlet port may include mounting a damper material on a frame. The frame may define an inner surface of the inlet port. The frame may further define a plurality of openings extending radially outward so that the damper material is in fluid communication with the airflow passing through the air inlet. The damper material may include an axially extending split. When the damper material is mounted on the frame, the inner circumference of the damper material may expand, i.e., the axial split may expand circumferentially to accommodate the frame. In one embodiment, the method 2000 may further include the step of attaching the plurality of inlet ports together to form the inlet muffler. This step may be performed after assembling at least one of the plurality of inlet ports. The step of attaching the plurality of inlet ports together may be performed before aligning the inlet muffler at step 2002.

[0118] This written description uses examples, including the best mode, to disclose the invention and also enables those skilled in the art to practice the invention, including making and using any device or system and performing any combined method. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. These other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims.

Claims

1. A power tool comprising: a main body, the main body comprising an air inlet; an inlet muffler disposed within the air inlet, the inlet muffler comprising a plurality of inlet ports, each of the plurality of inlet ports comprising an outer peripheral surface defining a port aperture therethrough, at least one of the plurality of inlet ports further comprising a damper material disposed on the outer peripheral surface of the at least one inlet port and further defining a port aperture therethrough; as well as a damper liner downstream of the inlet muffler, wherein at least one air gap is defined between the damper pad and the body of the power tool, The power tool defines a first sound intensity dB1 on an upstream side of the inlet muffler close to the outside of the power tool, and defines a second sound intensity dB2 on a downstream side of the inlet muffler, wherein dB1 is at least 10 dB smaller than dB2.

2. The power tool according to claim 1, wherein: At least one of the plurality of inlet ports comprises: a frame including a body extending between a first axial end and a second axial end of the air inlet, the body of the frame defining one or more openings through a radial surface thereof; and A damper material is disposed about the frame and in communication with air passing through the air inlet port through the one or more openings.

3. The power tool according to claim 2, wherein: The damper material includes polyurethane foam.

4. The power tool according to claim 2, wherein: The body of the frame includes an axially extending split.

5. The power tool according to claim 2, wherein: The frame defines a flared opening.

6. The power tool according to claim 2, wherein: The one or more openings define a damper material exposure ratio [A O / SA B ], the damper material is exposed more than the combined area A through all the openings O The surface area SA relative to the body of the frame B The damper material exposure ratio is measured to be at least 0.

2.

7. The power tool according to claim 1, wherein: The inlet muffler is detachable from the main body of the power tool.

8. The power tool according to claim 1, wherein: The plurality of inlet ports includes four to ten inlet ports.

9. The power tool according to claim 1, wherein: The plurality of inlet ports define an airflow path, and wherein the inlet muffler further comprises a plurality of auxiliary openings, each auxiliary opening defining an auxiliary airflow path angularly offset from the airflow path.

10. The power tool according to claim 1, wherein: The power tool includes a lawn mower, a compressor, an aerator, a forced air heater, a pump, a generator, a snow blower, a pressure washer, a chain saw, an edger, a trimmer, or a vacuum.

11. The power tool according to claim 1, wherein: The power tool includes a fluid pump.

12. The power tool according to claim 1, wherein: The power tool has a sound attenuation intensity of dB measured when the power tool is equipped with the inlet muffler. M , the non-silenced intensity dB measured when the power tool is not equipped with the inlet silencer U , the maximum muffler operating power capacity P measured when the power tool is equipped with the inlet muffler M , and the non-muffled operating power capacity P measured when the power tool is not equipped with the inlet muffler U , the power tool comprises: An operating power to damping loss ratio of at least 1.25 13. The power tool according to claim 12, wherein: The inlet silencer limits the airflow ratio The airflow is smaller than the cross-sectional area AF through which the airflow of the inlet muffler can pass without restriction. P The total cross-sectional area AF of the muffler relative to the inlet T The ratio of is measured and the airflow ratio is not less than 0.

8.

14. An outdoor power tool comprising an operating power to damping loss ratio of at least 1.25 in, dB M is the sound attenuation intensity when the outdoor power tool is equipped with an air inlet muffler, where dB U is the non-silenced intensity when the outdoor power tool is not equipped with an air inlet silencer, where P M is the maximum muffler operating power capacity when the outdoor power tool is equipped with the air inlet muffler, and where P U is the non-silenced operating power capacity when the outdoor power tool is not equipped with the air inlet muffler, wherein the power tool limits a first sound intensity dB1 on the upstream side of the inlet muffler close to the outside of the power tool, and limits a second sound intensity dB2 on the downstream side of the inlet muffler, wherein dB1 is at least 10 dB smaller than dB2.

15. The outdoor power tool according to claim 14, wherein: The air inlet muffler is arranged upstream of the noise source of the outdoor power tool, and the air inlet muffler comprises: a plurality of inlet ports, at least one of the plurality of inlet ports comprising: a frame including a body extending between a first axial end and a second axial end of the inlet port, the body of the frame defining one or more openings through a radial surface thereof; and A damper material is disposed about the frame and in communication with air passing through the inlet port via the one or more openings.

16. The outdoor power tool according to claim 15, wherein: The air inlet silencer limits the air flow ratio The air flow is smaller than the cross-sectional area AF through which the air flow of the air inlet silencer can pass without restriction. P The total cross-sectional area AF of the muffler relative to the air inlet T The ratio of is measured and the airflow ratio is not less than 0.

8.

17. The outdoor power tool according to claim 14, wherein: The outdoor power tool includes a lawn mower, a compressor, an aerator, a forced air heater, a pump, a generator, a snow blower, a pressure washer, a chain saw, an edger, a trimmer, or a vacuum.

18. The outdoor power tool according to claim 14, wherein: The outdoor power tool includes a fluid pump.

19. A method for damping a power tool, the method being used for installing the power tool according to any one of claims 1 to 13, comprising: Align the inlet muffler with respect to the air inlet of the power tool; as well as The inlet muffler is mounted on the air inlet, the inlet muffler comprising a plurality of inlet ports, each of the plurality of inlet ports comprising an outer peripheral surface, the outer peripheral surface defining a port aperture therethrough, at least one of the plurality of inlet ports further comprising a damper material disposed on the outer peripheral surface of the at least one inlet port and further defining a port aperture therethrough.

20. The method according to claim 19, further comprising: Prior to mounting the inlet muffler on the air inlet, at least one of the plurality of inlet ports is assembled, the step of assembling the at least one inlet port comprising mounting a damper material on a frame, wherein an inner periphery of the damper material expands when the damper material is mounted on the frame.

21. The method according to claim 20, further comprising: After assembling at least one of the plurality of inlet ports, the plurality of inlet ports are attached together to form the inlet muffler.

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