SE1850072A1

SE1850072A1 - Leaf blower

Info

Publication number: SE1850072A1
Application number: SE1850072A
Authority: SE
Inventors: Mikael Sahlberg
Original assignee: Husqvarna Ab
Priority date: 2018-01-24
Filing date: 2018-01-24
Publication date: 2019-07-25
Also published as: CN110067759B; SE543870C2; DE102019101077A1; CN110067759A

Abstract

A leaf blower (1) is disclosed comprising a housing (3) with an inlet (5) and an outlet (7), a fan (9) arranged in the housing (3), a motor (11) configured to drive the fan (9) to generate a flow of air from the inlet (5) to the outlet (7), and an air inlet screen (13) arranged at the inlet (5). The air inlet screen (13) is formed by a metal grid (15) delimiting openings (17), wherein the openings (17) constitute more than 70% of a surface area of the air inlet screen (13).

Description

Leaf Blower TECHNICAL FIELDThe present invention relates to a leaf blower, such as a hand-held leaf blower and abackpack leaf blower.

BACKGROUND A leaf blower is a tool that propels air out of an outlet to move debris, such as leaves, grasscuttings, dust, and the like. Leaf blowers comprise a fan powered by a motor, such as anelectric motor or a combustion engine. Leaf blowers are typically self-contained handheldunits, or backpack mounted units with a handheld outlet nozzle. Leaf blowers usuallycomprise an air inlet screen arranged at an inlet to prevent objects from entering the fan.Leaf blowers that comprise a combustion engine also comprise a fuel tank. Such a fuel tankmust be carried by a user and must be refilled when emptied. Leaf blowers that comprise anelectric motor usually comprise one or more batteries, which thus must be carried by the userand which must be recharged, or replaced, when emptied. The weight of a leaf blower is aproblem since a heavy leaf blower may be burdensome to use and may put strain on arms,and/or shoulders, of the user.

The driving of the fan of a leaf blower requires a lot of energy. There are thereforecontradictory requirements regarding available operational time of a leaf blower and theweight of the leaf blower. That is, the available operational time of a leaf blower comprisingan electric motor can be increased by increasing the size of the battery, or the batteries, butthe weight of the leaf blower will increase as a result thereof. Likewise, the availableoperational time of the leaf blower comprising a combustion engine can be increased byincreasing the size of the fuel tank. However, the weight of the leaf blower will increase as aresult thereof.

The fan of a leaf blower operates at a high power level, and as mentioned, the driving of thefan of a leaf blower requires a lot of energy. Therefore, air pollution and noise pollution areproblems associated with leaf blowers. The noise pollution, i.e. the noise level of a leafblower during operation, is caused by the motor and by the pumping of air by the fan fromthe inlet to the outlet of the leaf blower. Air pollution, as well as noise pollution, caused by aleaf blower may have negative health consequences for people and animals who are in thevicinity of the leaf blower.

SUMMARYlt is an object of the present invention to overcome, or at least alleviate, at least some of theabove-mentioned problems and drawbacks.

According to a first aspect of the invention, the object is achieved by a leaf blower comprisinga housing with an inlet and an outlet, a fan arranged in the housing, a motor configured todrive the fan to generate a flow of air from the inlet to the outlet, and an air inlet screenarranged at the inlet. The air inlet screen is formed by a metal grid delimiting openings,wherein the openings constitute more than 70% of a surface area of the air inlet screen.

Since the air inlet screen is formed by a metal grid delimiting openings, and since theopenings constitute more than 70% of a surface area of the air inlet screen, a low pressuredrop is obtained at the inlet of the leaf blower during operation of the leaf blower. As a resultthereof, a low flow resistance is provided of the air flowing through the inlet of the leaf blower.Thereby, the energy consumption of the motor can be reduced which improves the availableoperational time, and provides conditions for obtaining a lighter leaf blower by equipping theleaf blower with a smaller fuel tank, a smaller motor, and/or a smaller battery or batteries. ln addition, since a low pressure drop is obtained at the inlet of the leaf blower, the noisepollution caused by the leaf blower can be reduced. This because the motor and the fan canoperate at a reduced power level, given a certain flow rate of air through the outlet of thehousing. Further, since the motor and the fan can operate at a reduced power level, a leafblower is provided potentially capable of operating at reduced air emissions levels.

Further, since the air inlet screen is formed by a metal grid, a robust air inlet screen isprovided capable of preventing objects from entering the fan.

Accordingly, a leaf blower is provided overcoming, or at least alleviating, at least some of theabove-mentioned problems and drawbacks. As a result, the above-mentioned object isachieved.

Optionally, the openings are substantially evenly distributed on the air inlet screen. Thereby,a robust air inlet screen is provided, and the air inlet screen can be provided with a highability to hinder passage of objects through the air inlet screen despite the fact that theopenings constitute a great proportion of the surface area of the air inlet screen. 3 Optionally, the width of portions of the metal grid between adjacent openings is substantiallyuniform over the entire metal grid. Thereby, a robust air inlet screen is provided, and the airinlet screen can be provided with a high ability to hinder passage of objects through the airinlet screen despite the fact that the openings constitute a great proportion of the surfacearea of the air inlet screen.

Optionally, the width is within the range of 0.7 - 1.5 mm. Thereby, a robust air inlet screen isprovided, while it is ensured that the air inlet screen is capable of preventing objects fromentering the fan.

Optionally, the thickness of the metal grid is within the range of 0.3 - 0.8 mm. Thereby, arobust air inlet screen is provided, while it is ensured that a low pressure drop is obtainedover the air inlet screen during operation of the leaf blower. Further, it is ensured that the airinlet screen is capable of preventing objects from entering the fan.

Optionally, the metal grid is a steel grid. Thereby, a leaf blower is provided having a robust air inlet screen.

Optionally, the openings are polygonally shaped. Thereby, a robust air inlet screen isprovided. Further, an air inlet screen is provided with improved particle hindering capabilities,given the low pressure drop obtained over the air inlet screen during operation of the leaf blower.

Optionally, the openings are hexagonally shaped. Thereby, a robust air inlet screen isprovided. Further, an air inlet screen is provided with improved particle hindering capabilities,given the low pressure drop obtained over the air inlet screen during operation of the leaf blower.

Optionally, the metal grid is honeycomb shaped. Thereby, a robust air inlet screen isprovided. Further, an air inlet screen is provided with improved particle hindering capabilities,given the low pressure drop obtained over the air inlet screen during operation of the leaf blower.

Optionally, each of a plurality of openings comprise two parallel sides longer than theremaining sides. Thereby, an air inlet screen is provided with potentially further improvedparticle hindering capabilities, given the low pressure drop obtained over the air inlet screenduring operation of the leaf blower.

Optionally, the metal grid is produced from a sheet of metal, and wherein the openings areconfigured as through-holes in the sheet of metal. Thereby, a robust air inlet screen isprovided. Further, a low pressure drop is obtained over the air inlet screen during operationof the leaf blower. ln addition, an air inlet screen is provided having conditions for beingmanufactured in a cost-efficient manner.

Optionally, the openings are produced by etching portions of the sheet of metal. Thereby, theopenings can be arranged in a complex pattern providing a high rigidity and robustness ofthe air inlet screen, and a low pressure drop over the air inlet screen during operation of theleaf blower.

Optionally, the openings are produced by punching portions of the sheet of metal. Thereby,an air inlet screen is provided having conditions for being manufactured in a cost-efficient manner.

Optionally, the metal grid comprises metal wires woven into the metal grid. Thereby, an airinlet screen is provided having conditions for being manufactured in a cost-efficient manner.

Optionally, each opening is provided with dimensions ensuring hinderance of passage of aspherical object having a diameter of more than 7 mm through the air inlet screen. Thereby,a leaf blower is provided having a low pressure drop at the inlet of the leaf blower duringoperation, while the air inlet screen of the leaf blower is capable of hindering passage ofobjects having a width greater than 7 mm.

Optionally, the motor is an electric motor. Thereby, an environmentally friendly leaf blower isprovided capable of generating low levels of air emissions and noise emissions duringoperation. Further, since the leaf blower comprises an air inlet screen providing a lowpressure drop at the inlet of the leaf blower, conditions are provided for using a smallerelectric motor than would be the case otherwise, which can reduce the weight of the leafblower. Further, a leaf blower is provided with potentially more operational time available.Still further, conditions are provided for using a smaller battery or batteries, than would be thecase otherwise, which can reduce the weight of the leaf blower.

Optionally, the leaf blower comprises at least one battery configured to power the electricmotor. Since the leaf blower comprises an air inlet screen providing a low pressure drop atthe inlet of the leaf blower, the potential available battery time is increased, and conditions are provided for using a smaller battery or batteries, than would be the case otherwise, whichcan reduce the weight of the leaf blower.

Further features of, and advantages with, the present invention will become apparent whenstudying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS Various aspects of the invention, including its particular features and advantages, will bereadily understood from the example embodiments discussed in the following detaileddescription and the accompanying drawings, in which: Fig. 1 illustrates a leaf blower, according to some embodiments, Fig. 2 illustrates an air inlet screen unit of the leaf blower, illustrated in Fig. 1 Fig. 3 illustrates a portion of the air inlet screen unit, illustrated in Fig. 2, and Fig. 4 illustrates an air inlet screen unit, according to some further embodiments.

DETAILED DESCRIPTION Aspects of the present invention will now be described more fully. Like numbers refer to likeelements throughout. Well-known functions or constructions will not necessarily be describedin detail for brevity and/or clarity.

Fig. 1 illustrates a leaf blower 1 according to some embodiments. The leaf blower 1comprises a housing 3 with an inlet 5 and an outlet 7. The leaf blower 1 further comprises afan 9 arranged in the housing 3, and a motor 11 configured to drive the fan 9 to generate aflow of air from the inlet 5 to the outlet 7. According to the illustrated embodiments, the leafblower 1 comprises an outlet nozzle 2 connected to the outlet 7 of the housing 3. The outletnozzle 2 is provided with a flexible bellow portion 4. Further, according to the illustratedembodiments, the leaf blower 1 comprises a handle portion 6 at an upper portion of the leafblower 1. The handle portion 6 facilitates transport of the leaf blower 1, when the leaf bloweris not in use. According to the illustrated embodiments, the motor 11 is an electric motor. Theleaf blower 1 comprises a second housing 8 accommodating a battery 37, and a frame 10supporting the housing 3 and the second housing 8. The battery 37 is a rechargeable batteryconfigured to power the electric motor 11 during operation of the leaf blower 1. According tothe illustrated embodiments, the leaf blower 1 is a backpack mounted leaf blower, and maythus be referred to as a backpack leaf blower. The leaf blower 1 comprises shoulder strapsconnected to the frame 10. The shoulder straps are not visible in Fig. 1. The shoulder strapsallow a user to carry the leaf blower 1 on the back of the user. That is, during use of the leaf 6 blower 1 according to the illustrated embodiments, the frame 10 holding the housing 3 andthe second housing 8 can rest on the back of the user, and the user may grab the outletnozzle 2 with a hand to direct the air flowing from the outlet nozzle 2, to move debris such asleaves, grass cuttings, dust, and the like.

The leaf blower 1 further comprises an air inlet screen unit 12 arranged at the inlet 5. The airinlet screen unit 12 comprises an air inlet screen 13. The air inlet screen 13 is arranged tohinder objects greater than a certain size to enter the housing 3. lf an object would enter thehousing 3, the object could damage the fan 9 and/or the motor 11.

Fig. 2 illustrates the air inlet screen unit 12 of the leaf blower 1, illustrated in Fig. 1. The airinlet screen unit 12 comprises a frame 14 and an air inlet screen 13 mounted onto the frame14. The air inlet screen unit 12 may further comprise a sealing or gasket between the air inletscreen 13 and the frame 14. The frame 14 may be provided in a polymeric material and may,as illustrated in Fig. 2, comprise one or more attachment arrangements 16 configured tofacilitate mounting of the air inlet screen unit 12 onto an inlet of a leaf blower. The air inletscreen 13 is formed by a metal grid 15 delimiting openings 17, i.e. through holes. Accordingto the illustrated embodiments, the openings 17 constitute 75% of a surface area of the airinlet screen 13. The surface area of the air inlet screen 13 is substantially perpendicular to anintended air flow direction through the air inlet screen 13. According to further embodiments,the openings 17 may constitute 70% - 90%, 75% - 90%, or 80% - 90% of the surface area ofthe air inlet screen 13. Thus, according to these embodiments, the openings 17 constitute agreat proportion of the surface area of the air inlet screen 13. As a result thereof, a lowpressure drop over the air inlet screen 13 is obtained during operation of the leaf blower 1.Further, since the air inlet screen unit 12 is formed by a metal grid 15, a robust air inletscreen 13 is provided, despite the fact that the openings 17 constitute a great proportion ofthe surface area of the air inlet screen 13. As seen in Fig. 2, the openings 17 aresubstantially evenly distributed on the air inlet screen 13.

Fig. 3 illustrates a portion of the air inlet screen 13, illustrated in Fig. 2. According to theillustrated embodiments, the width w of portions 23 of the metal grid 15 between adjacentopenings 17', 17",17”' is substantially uniform over the entire metal grid 15. As a resultthereof, a robust air inlet screen 13 is provided and the air inlet screen 13 is provided with ahigh ability to hinder passage of objects through the air inlet screen 13 despite the fact thatthe openings 17 constitute a great proportion of the surface area of the air inlet screen 13.According to the illustrated embodiments, the width w is 1 mm. According to furtherembodiments, the width w of portions 23 of the metal grid 15 between adjacent openings 17', 7 17“,17'" may be within the range of 0.7 - 1.5 mm, or 0.85 - 1.15 mm, which provides arobust air inlet screen 13 having a high ability to hinder passage of objects through the airinlet screen 13 despite the fact that the openings 17 constitute a great proportion of thesurface area of the air inlet screen 13.

Further, according to the illustrated embodiments, the openings 17 are hexagonally shapedand the metal grid 15 delimiting the hexagonally shaped openings 17 is honeycomb shaped.As a result thereof, a robust air inlet screen 13 is provided and the air inlet screen 13 can beprovided with an improved ability to hinder passage of objects through the air inlet screen 13despite the fact that the openings 17 constitute a great proportion of the surface area of theair inlet screen 13. ln addition, according to the illustrated embodiments, and as also seen in Fig. 2, most of theopenings 17 comprise two parallel sides 25 longer than the remaining sides 27. Thereby, theair inlet screen 13 can provide a still further improved ability to hinder passage of objectsthrough the air inlet screen 13, and/or a further lowered flow resistance. According to theillustrated embodiments, the distance between two parallel longer sides 25 is 5.5 mm. Thatis, the width of an opening 17, measured in the direction d1 indicated in Fig. 3 is 5.5 mm. Thewidth of an opening 17 measured in the direction d2, indicated in Fig. 3, is 19 mm. Thus, themetal grid 15, according to the embodiments illustrated in Fig. 2 and Fig. 3, is provided withdimensions ensuring hinderance of passage of a spherical object having a diameter of morethan 5.5 mm. According to further embodiments, each opening 17 may be provided withdimensions ensuring hinderance of passage of a spherical object having a diameter of morethan 6.35 mm, or more than 7 mm through the air inlet screen 13.

According to further embodiments, the openings 17 may have a polygonal shape other thana hexagonal shape, such as a triangular shape, a quadrilateral shape, a pentagonal shape, aheptagonal shape, or an octagonal shape.

According to the illustrated embodiments, the thickness of the metal grid 15 is approximately0.5 mm. According to further embodiments, the thickness of the metal grid 15 may be withinthe range of 0.3 - 0.8 mm, or 0.4 - 0.6 mm. Thereby, a rigid and robust air inlet screen 13 isprovided and a low flow resistance through the air inlet screen 13 is ensured. Further, sincethe air inlet screen 13 is formed by a metal grid 15, the air inlet screen 13 can be providedwith a small thickness, which reduces the flow resistance through the air inlet screen 13. Thethickness of the metal grid 15 is measured in the intended flow direction of air through themetal grid 15, i.e. in a direction perpendicular to extension directions of d1, d2 of the metal 8 grid 15. The surface area of the air inlet screen 13 extends along the extension directions d1,d2 of the metal grid 15. According to some embodiments, the metal grid 15 is a steel grid, i.e.made from steel, such as a stainless steel, for example SS-EN 10151 X10CrNi18-8 1.4310.The metal grid 15 may comprise a protective coating such as a paint and/or a lacquer.

According to the illustrated embodiments, the metal grid 15 is produced from a sheet of metal29, and the openings 17 are configured as through-holes in the sheet of metal 29. That is,the metal grid 15 is produced by removing portions 31 of a sheet of metal 29. According tosome embodiments, the openings 17 are produced by etching portions 31 of the sheet ofmetal 29. Thereby, the openings 17 can be arranged in a complex pattern providing a highrigidity and robustness of the air inlet screen 13 and a low pressure drop over the air inletscreen 13 during operation of the leaf blower. According to further embodiments, theopenings 17 are produced by punching portions 31 of the sheet of metal 29.

Fig. 4 illustrates an air inlet screen unit 12, according to some further embodiments. The airinlet screen unit 12 comprises a frame 14 and an air inlet screen 13 mounted onto the frame14. According to these embodiments, a metal grid 15 of the air inlet screen 13 comprisesmetal wires 33 woven into the metal grid 15. According to the illustrated embodiments, themetal wires 33 delimit openings 17, i.e. through holes. The air inlet screen unit 12 mayfurther comprise a sealing or gasket between the air inlet screen 13 and the frame 14. Theframe 14 may be provided in a polymeric material and may, as illustrated in Fig. 4, compriseone or more attachment arrangements 16 configured to facilitate mounting of the air inlet screen unit 12 onto an inlet of a leaf blower.

According to the illustrated embodiments, the metal wires 33 are woven into the metal grid15 such that the openings are formed as squares. According to further embodiments, most ofthe openings 17 may comprise two parallel sides longer than the remaining sides. Accordingto such embodiments, the metal wires 33 may be woven into the metal grid 15 such that theopenings are formed as rectangles.

According to the illustrated embodiments, each metal wire 33 has a width of 0.5 mm and thedistance between two adjacent metal wires 33 extending in the same direction is 5 mm.Thus, according to the illustrated embodiments, the width of the openings 17, measured inthe extension directions d1, d2 of the metal wires 33, is 5 mm. Accordingly, according to theillustrated embodiments, each opening 17 is provided with dimensions ensuring hinderanceof passage of a spherical object 35 having a diameter of more than 5 mm through the air inletscreen 13. According to further embodiments, each metal wire 33 may have a width within 9 the range of 0.3 - 0.8 mm, or 0.4 - 0.6 mm, which provides a robust air inlet screen 13having a high ability to hinder passage of objects through the air inlet screen 13 despite thefact that the openings 17 constitute a great proportion of the surface area of the air inletscreen 13. Further, the distance between two adjacent metal wires 33 extending in the samedirection may be within the range of 3 - 7 mm, or 4 - 6 mm. Thus, the width of the openings17, measured in the extension directions d1, d2 of the metal wires 33, may be within therange of 3- 7 mm, or4 - 6 mm.

According to the illustrated embodiments, the openings 17 constitute 80% of a surface areaof the air inlet screen 13. The surface area of the air inlet screen 13 is substantiallyperpendicular to an intended air flow direction through the air inlet screen 13. Further, thesurface area of the air inlet screen 13 extends along the extension directions d1, d2 of themetal wires 33. According to further embodiments, the openings 17 may constitute 70% -90%, 75% - 90%, or 80% - 90% of the surface area of the air inlet screen 13. Thus,according to these embodiments, the openings 17 constitute a great proportion of the surfacearea of the air inlet screen 13. As a result thereof, a low pressure drop over the air inletscreen 13 is obtained during operation of the leaf blower 1. Further, since the air inlet screenunit 12 comprises metal wires 33 woven into the metal grid 15, a robust air inlet screen 13 isprovided, despite the fact that the openings 17 constitute a great proportion of the surfacearea of the air inlet screen 13. lt is to be understood that the foregoing is illustrative of various example embodiments andthat the invention is defined only by the appended claims. A person skilled in the art willrealize that the example embodiments may be modified, and that different features of theexample embodiments may be combined to create embodiments other than those describedherein, without departing from the scope of the present invention, as defined by theappended claims. According to the embodiments illustrated in Fig. 1, the leaf blower 1 is abackpack mounted leaf blower. According to further embodiments, the leaf blower 1, asreferred to herein, may be a hand-held leaf blower. The wording “leaf blower” as used hereinis intended to encompass a tool configured to move debris by generating a flow of airthrough an outlet. Thus, the main field of application of the “leaf blower” may be anotherapplication than moving leaves. For example, the leaf blower, as referred to herein, may besold and marketed as a blower configured to move debris, such as dust. Therefore,throughout this disclosure, the wording “leaf blower” can be replaced by the wording “blower”or by the wording “tool configured to move debris by generating a flow of air through anoutlet”.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one ormore stated features, elements, steps, components or functions but does not preclude thepresence or addition of one or more other features, elements, steps, components, functionsor groups thereof.

Claims

1. A leaf blower (1) comprising: - a housing (3) with an inlet (5) and an outlet (7),- a fan (9) arranged in the housing (3),- a motor (11) configured to drive the fan (9) to generate a flow of air from the inlet (5)to the outlet (7), and- an air inlet screen (13) arranged at the inlet (5),characterized in that the air inlet screen (13) is formed by a metal grid (15) delimitingopenings (17), wherein the openings (17) constitute more than 70% of a surface area ofthe air inlet screen (13). The leaf blower (1) according to claim 1, wherein the openings (17) are substantiallyevenly distributed on the air inlet screen (13). The leaf blower (1) according to claim 1 or 2, wherein the width (w) of portions (23) of themetal grid (15) between adjacent openings (17', 17",17'”) is substantially uniform overthe entire metal grid (15). The leaf blower (1) according to claim 3, wherein the width (w) is within the range of 0.7 -1.5mm. The leaf blower (1) according to any one of the preceding claims, wherein the thicknessof the metal grid (15) is within the range of 0.3 - 0.8 mm. The leaf blower (1) according to any one of the preceding claims, wherein the metal grid(15) is a steel grid. The leaf blower (1) according to any one of the preceding claims, wherein the openings(17) are polygonally shaped. The leaf blower (1) according to claim 7, wherein the openings (17) are hexagonallyshaped. The leaf blower (1) according to claim 8, wherein the metal grid (15) is honeycombshaped. The leaf blower (1) according to any one of the claims 7 - 9, wherein each of a pluralityof openings (17) comprise two parallel sides (25) longer than the remaining sides (27). The leaf blower (1) according to any one of the preceding claims, wherein the metal grid(15) is produced from a sheet of metal (29), and wherein the openings (17) areconfigured as through-holes in the sheet of metal (29). The leaf blower (1) according to claim 11, wherein the openings (17) are produced byetching portions (31) of the sheet of metal (29). The leaf blower (1) according to claim 11, wherein the openings (17) are produced bypunching portions (31) of the sheet of metal (29). The leaf blower (1) according to any one of the claims 1 - 10, wherein the metal grid (15)comprises metal wires (33) woven into the metal grid (15). The leaf blower (1) according to any one of the preceding claims, wherein each opening(17) is provided with dimensions ensuring hinderance of passage of a spherical object(35) having a diameter of more than 7 mm through the air inlet screen (13). (internalrequirement for Husqvarna is 6.35 mm) The leaf blower (1) according to any one of the preceding claims, wherein the motor (11)is an electric motor. The leaf blower (1) according to claim 16, wherein the leaf blower (1) comprises at leastone battery (37) configured to power the electric motor (11).