SE1951341A1

SE1951341A1 - A battery lock mechanism for a battery compartment and an electrically powered hand-held work tool comprising such a battery lock mechanism

Info

Publication number: SE1951341A1
Application number: SE1951341A
Authority: SE
Inventors: Robert Lerbro
Original assignee: Husqvarna Ab
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2021-05-26
Also published as: SE543800C2

Abstract

A battery lock mechanism (700) for a battery compartment (150), the battery lock mechanism comprising a locking member (710) rotatably supported on a shaft (720), the locking member comprising a leading edge portion (750) arranged to enter a recess (760) formed in the electrical energy source (220) to lock the electrical energy source in position, wherein the leading edge portion (750) has an arcuate form with a curvature corresponding to that of a circle segment with radius (740) corresponding to the distance from the leading edge portion (750) to the center of the shaft (720), and wherein the recess (760) formed in the energy source (220) comprises a surface (770) arranged to engage the leading edge portion (750), wherein the surface (770) has an arcuate form to match that of the leading edge portion (750).

Description

TECHNICAL FIELD The present disclosure relates to electrically powered hand-held workequipment such as cut-off tools and saws for cutting concrete and stone.

BACKGROUND Hand-held work tools for cutting and/or abrading hard materials such asconcrete and stone comprise powerful motors in order to provide the requiredpower for processing the hard materials. These motors generate a substantialamount of heat and therefore need to be cooled in order to preventoverheating. Electrical work tools generate heat by the electrical motor, andalso by the battery and control electronics. There is a need for efficientmethods of cooling such work tools.

The work tools also normally generate vibration which may be harmful or atleast cause discomfort to an operator of the tool. lt is desired to protect theoperator from prolonged exposure to strong vibration.

The environments in which these types of tools are used are often harsh. Thework tools are exposed to water, dust, debris and slurry, which may affect toolperformance negatively. For instance, slurry may accumulate in the work toolinterior where it eventually causes tool failure. lt is desired to prevent accumulation of dust and slurry in the work tool interior.

Ease of operation is especially important for work tools used on constructionsites. For electrical work tools, it is desirable that in-field battery change canbe made in an efficient and convenient manner where the battery is easy toinsert in the work tool, where the battery is snugly held in the work tool, andwhere the battery is easily released from the work tool.

To summarize, there are challenges associated with hand-held work tools.

SUMMARY lt is an object of the present disclosure to provide improved hand-held worktools which address the above-mentioned issues. This object is at least on partobtained by a hand-held work tool comprising a first part and a second partarranged vibrationally iso|ated from each other. The first part comprises aninterface for holding a cutting tool and an electric motor arranged to drive thecutting tool. The electric motor is arranged to drive a fan configured to generatea flow of cooling air for cooling the electric motor. The second part comprisesa battery compartment for holding an electrical storage device arranged topower the electric motor. A cooling air conduit is arranged to guide a portion ofthe flow of cooling airfrom the first part and into the second part for cooling theelectrical storage device.

The main vibration generating parts of the work tool are comprised in the firstpart. Thus, by vibrationally isolating the first part from the second part, theamount of vibration propagating to the second part is significantly reduced.The second part may, e.g., comprise front and rear handles which are thenvibrationally iso|ated from the vibration sources in the first part. Since vibrationis reduced, an operator may use to tool longer and with an increased comfort-level. A single fan unit is used to cool both the electric motor and the electricalenergy source. This is an advantage since there is no need for a second fanunit arranged in the second part. Efficient cooling of both the electric motor and of the electrical energy source is provided.

According to aspects, the fan comprises an axial fan portion arrangedperipherally on the fan and a radial fan portion arranged centrally on the fan.The axial fan portion is arranged to generate the flow of cooling air for coolingthe electric motor, and the radial fan portion is arranged to generate the portionof the flow of cooling air from the first part and into the second part for coolingthe electrical storage device. This way the portion of cooling air guided into thesecond part is not first heated by the electric motor, which improves the coolingeffect. Also, the radial fan is better when it comes to pushing air flows though the conduit to the second part, which may comprise bends and narrowsecüons.

The fan may be assembled in a fan housing comprising at least one openingarranged peripherally in the housing for receiving the flow of cooling air forcooling the electric motor, and a fan scroll arranged centrally in the housing forguiding the portion of the flow of cooling air from the first part and into thesecond part for cooling the electrical storage device. This way the portion ofthe flow of cooling air from the first part and into the second part is efficiently pushed into the second part, which improves the cooling effect.

According to some aspects, the portion of the flow of cooling air guided fromthe first part and into the second part passes via a bellows or other flexible airflow conduit arranged in-between the first and the second parts. The flexibleair flow conduit provides a connection between the first part and the secondpart which is able to withstand vibration, and which does not forward significantlevel of vibration from the first part to the second part. Other possible flexibleair flow conduits may, e.g., comprise rubber or plastic hoses, and jointed sectioned conduits able to flex in two or more directions.

According to some other aspects, the bellows comprises a poka-yoke featurecomprising at least one protrusion configured to enter a corresponding recessformed in the first part and/or in the second part, thereby preventing erroneousassembly of the bellows with the first and second parts. The poka-yoke featureprevents erroneous assembly, leading to a more efficient and less error prone assembly process, which is an advantage.

According to some further aspects, the bellows or other flexible air flow conduitcomprises at least one edge portion of increased thickness, wherein eachedge portion is arranged to enter a corresponding groove formed in the firstpart or in the second part, thereby fixing the bellows in relation to the first orsecond part. This arrangement provides a secure attachment between the bellows and the work tool body and is also easily assembled.

According to aspects, the bellows is arranged with a shape that is symmetricabout a symmetry plane parallel to an extension direction of the edge portions.

The symmetric shape simplifies assembly since the bellows need not beturned in any specific way before assembly.

According to aspects, the portion of the flow of cooling air from the first partand into the second part is arranged to pass a control unit of the hand-heldwork tool. This way the control unit is also cooled by the portion of the flow ofcooling air, which is an advantage since there is no need for a separate coolingfan or the like for cooling the control unit. The control unit cooling may befurther improved by arranging a cooling flange in connection to the control unit.

According to some aspects, the first part comprises a belt guard configured toenclose an interior space. A portion of the flow of cooling air is arranged to beguided into the interior space, thereby increasing an air pressure in the belt guard interior space above an ambient air pressure level.

This way water, dust, debris and slurry is at least in part prevented fromentering an interior of the work tool where it may accumulate to eventuallycause work tool failure. lt is an advantage that the build-up of dust and debris in the work tool interior is reduced.

According to some other aspects, the first part comprises a thermallyconductive cut-off arm arranged to support the circular cutting tool on a firstend of the cut-off arm, and to support the electric motor by a support surfaceat a second end of the cut-off arm opposite to the first end, wherein the cut-offarm comprises one or more cooling flanges arranged to conduct heat awayfrom the electric motor via the support surface. The cooling flanges improveheat dissipation from the electric motor via the cut-off arm, which is anadvantage. The support surface improves a thermal coupling between theelectric motor and the cut-off arm, thereby improving heat dissipation from theelectric motor, which is an advantage.

According to some further aspects, the cut-off arm is arranged to at leastpartially enclose the electric motor. The cut-off arm thereby protects theelectric motor and also has the function of transporting heat away from the electric motor.

According to aspects, the cut-off arm and the electric motor are at least partiallyintegrally formed. This means that the cut-off arm and the electric motor mayshare some parts. For instance, a part of the electric motor housing may be formed by the cut-off arm material. This part may, e.g., be a motor gable.

According to aspects, at least 30% of a volume of the electric motor is enclosedby the cut-off arm. Thus, the electric motor is significantly embedded into thecut-off arm, thereby providing both improved motor protection and heattransport.

According to aspects, the battery compartment comprises a battery lockmechanism, the battery lock mechanism comprising a locking memberrotatably supported on a shaft, the locking member comprising a leading edgeportion arranged to enter a recess formed in the electrical energy source tolock the electrical energy source in position. The leading edge portion has anarcuate form with a curvature corresponding to that of a circle segment withradius corresponding to the distance from the leading edge portion to thecenter of the shaft. The recess formed in the energy source comprises asurface arranged to engage the leading edge portion, wherein the surface hasan arcuate form configured to match that of the leading edge portion.

This battery lock mechanism allows for inserting a battery into the batterycompartment in an effortless manner. The battery lock mechanism thensecurely holds the battery in position until it is to be removed. The arcuate formof the leading edge portion and the matching surface in the recess allows fora convenient release of the battery from the battery compartment.

According to some aspects, the battery compartment comprises at least oneresilient member arranged to urge the electrical energy source into the lockingposition, wherein the at least one resilient member and the battery lockmechanism are arranged at opposite sides of the battery compartment.

The at least one resilient member biases the battery into the locked position,thereby providing a more secure fastening of the battery. Also, by arrangingthe resilient member and the locking mechanisms on opposite sides, a twistingmotion by the battery in relation to the battery compartment is obtained, similar to a stuck desk drawer which further secures the battery in the battery compartment.

According to some aspects, the locking member is spring biased towards thelocking position, and operable by means of a lever or push-button mechanism.The biasing allows for an at least partly automatic locking function, while thelever or push-button mechanism can be conveniently operated by a user of thetool, which is an advantage.

Generally, all terms used in the claims are to be interpreted according to theirordinary meaning in the technical field, unless explicitly defined otherwiseherein. All references to "a/an/the element, apparatus, component, means,step, etc." are to be interpreted openly as referring to at least one instance ofthe element, apparatus, component, means, step, etc., unless explicitly statedotherwise. The steps of any method disclosed herein do not have to beperformed in the exact order disclosed, unless explicitly stated. Furtherfeatures of, and advantages with, the present invention will become apparentwhen studying the appended claims and the following description. The skilledperson realizes that different features of the present invention may becombined to create embodiments other than those described in the following,without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will now be described in more detail with reference tothe appended drawings, where Figure 1 shows an example work tool; Figures 2A-C show views of another example work tool;Figures 3A-B show views of a work tool cut-off arm;Figures 4-6 illustrate bellows for guiding an air flow;Figures 7A-C schematically illustrate a locking mechanism; Figure 8 shows an example work tool with a battery locking mechanism; Figure 9 schematically illustrates details of a battery lock mechanism;Figures 10A-C show views of an example work tool; Figure 11 schematically illustrates a fan; Figure 12 shows an example fan for a work tool; and Figure 13 shows an example fan housing.

DETAILED DESCRIPTION The invention will now be described more fully hereinafter with reference to theaccompanying drawings, in which certain aspects of the invention are shown.This invention may, however, be embodied in many different forms and shouldnot be construed as limited to the embodiments and aspects set forth herein;rather, these embodiments are provided by way of example so that thisdisclosure will be thorough and complete, and will fully convey the scope ofthe invention to those skilled in the art. Like numbers refer to like elements throughout the description. lt is to be understood that the present invention is not limited to theembodiments described herein and illustrated in the drawings; rather, theskilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

Figure 1 shows a hand-held work tool 100. The work tool 100 in Figure 1comprises a rotatable circular cutting tool 130, but the techniques disclosedherein can also be applied to other cutting tools such as chain-saws, core drills,and the like. An electric motor 140 is arranged to drive the cutting tool. Thismotor is powered from an electrical energy storage device which is arrangedto be held in a battery compartment 150.

The electrical motor generates a substantial amount of heat during operation.To prevent the motor from overheating, a fan 145 is arranged to be driven bythe motor 140. This fan may, e.g., be attached directly to the motor axle, or by some means of transmission arrangement. The fan generates an airflow which transports heat away from the electric motor, thereby cooling the motor.

The work tool 100 is arranged to be held by a front handle 190 and a rearhandle 195 and operated by a trigger 196 in a known manner. lt is desirable tominimize vibration in the handles and trigger, since excessive vibration may beuncomfortable for an operator using the work tool 100. Excessive vibrationmay also reduce the lifetime of tool components such as cable connectionsand electronics. To reduce these vibrations, the work tool 100 comprises a firstpart 110 and a second part 120 arranged vibrationally isolated from each other.The first part 110 comprises an interface for holding the cutting tool 130 andalso comprises the electric motor 140 arranged to drive the cutting tool. Thus,the first part comprises the main vibration generating elements of the work tool.

Notably, the second part 120 comprises the handles 190, 195 and the trigger196 and therefore is the part which interfaces with the operator of the work tool100. The second part 120 also comprises the battery compartment 150 forholding the electrical storage device, and the control electronics for controlling various operations of the work tool 100.

Since vibration generated in the first part 110 is not transferred, or at least nottransferred in a significant amount, to the second part 120, an operator of thedevice 100 will not be subjected to the vibration, which is an advantage sincehe or she may be able to work for a longer period of time under morecomfortable work conditions.

Vibration is normally measured in units of m/s2, and it is desired to limit toolvibration in front and rear handles below 2.5 m/s2. Tool vibration, guidelinesfor limiting tool vibration, and measurement of the tool vibration are discussedin "VIBRATIONER - Arbetsmiljöverkets föreskrifter om vibrationer samtallmänna råd om tillämpningen av föreskrifterna", Arbetsmiljöverket, AFS2005:15.

According to some aspects, the work tool 100 comprises a first part 110 and asecond part 120 arranged vibrationally isolated from each other by a vibration isolation system arranged to limit front and rear handle vibration to valuesbelow 2.5 m/s2.

A cooling air conduit is arranged to guide a portion of the flow of cooling air160 from the first part 110 and into the second part 120 for cooling the electricalstorage device. This means that the fan 145 is used to cool both the electricalmotor 140, and the electrical energy source, which is an advantage since onlya single fan is needed.

Herein, a conduit is a passage arranged to guide a flow, such as a flow of air.A cooling air conduit may be formed as part of an interior space enclosed bywork tool body parts, or as a hose of other type of conduit, or as a combinationof different types of conduits.

Any control electronics comprised in the second part 120 may also be arrangedto be cooled by the portion of the flow of cooling air 160 which is guided fromthe first part 110 and into the second part 120. Figure 1 schematically showsa cooling flange 180 associated with such control electronics, which coolingflange 180 is optional, i.e., the portion of the flow of cooling air can be used tocool the control unit directly in which case the control unit constitutes thecooling flange. Thus, optionally, the portion of the flow of cooling air 160 fromthe first part 110 and into the second part 120 is arranged to pass a coolingflange 180 associated with a control unit of the hand-held work tool 100. lt may be a challenge to efficiently guide the portion of air 160 from the firstpart and into the second part, at least partly since the first part and the secondpart are arranged vibrationally isolated from each other. Some aspects of thedisclosed work tool solve this challenge by providing bellows or some othertype of flexible air flow conduit between the first part and the second part toguide the portion of airfrom the fan 145 towards the battery compartment 150.These bellows 170 will be discussed in more detail below in connection toFigures 4-6. Bellows are sometimes also referred to as flexible covers,convolutions, accordions or machine way covers. A hose formed in a flexible material may be used instead of the bellows.

To summarize, Figure 1 schematically illustrates a hand-held work tool 100comprising a first part 110 and a second part 120 arranged vibrationallyisolated from each other. According to some aspects, the first part 110 isvibrationally isolated from the second part 120 by one or more resilient elements.

The hand-held work tool may be a cut-off tool as shown in Figure 1, but it canalso be a chain saw or other work tool for cutting hard materials. The first partcomprises an interface for holding a cutting tool 130 and an electric motor 140arranged to drive the cutting tool. The drive arrangement may, e.g., comprisea belt drive or a combination of belt drive and geared transmission. The electricmotor 140 is arranged to drive a fan 145 configured to generate a flow ofcooling air for cooling the electric motor 140. The fan may, e.g., be directlyconnected to the electric motor shaft, or it can be indirectly connected to themotor shaft via some sort of transmission or drive arrangement, like a belt drive or a geared transmission.

The second part 120 comprises a battery compartment 150 for holding anelectrical storage device arranged to power the electric motor 140, and acooling air conduit is arranged to guide a portion of the flow of cooling air 160from the first part 110 and into the second part 120 for cooling the electricalstorage device. The electrical energy source may be a battery, or some typeof fuel-cell or the like.

Figures 2A-C show different views of an example hand-held work tool 200arranged to hold a cutting tool by a cutting tool interface 260. The resilientelements separating the first part 110 from the second part 120 are herecompression springs 210. However, as mentioned above, some type ofresilient material members, such as rubber bushings, may also be used as analternative to the springs or in combination with the springs. Leaf springs mayalso be an option for vibrationally isolating the first part 110 from the secondpart 120.

Figure 2B shows a holder 270 for an extra blade bushing. Cutting blades mayhave varying dimensions when it comes to the central hole in the blade. Some 11 blade holes are 20mm across, while some other holes are 25,5mm across.There are even some markets where blade central holes of 30,5mm arecommon. To allow use with different types of blades, having differentdimensions on the central blade hole, the hand-held work tool 200 comprisesa holder 270 arranged on the work tool body for holding a blade bushing. Thisextra blade bushing preferably has a different dimension compared to theblade bushing mounted in connection to the cutting tool interface 260.

Figure 2A shows an example electrical storage device 220, here a battery,fitted in the battery compartment 150. This battery may be held in position bymeans of a battery lock mechanism which will be discussed in more detailbelow in connection to Figures 7A-C, 8, and 9.

According to some aspects, the flow of cooling air for cooling the electric motor140 extends transversally 230, 245, 201 through the hand-held work tool, withrespect to an extension plane of the circular cutting tool 130. Here, withreference to Figure 2C, transversally is to be interpreted relative to anextension direction 202 of the work tool extending from the rear handle 195towards the cutting tool and in relation to an extension plane of the cutting tool130 (which is more or less vertical in Figure 2C). Air from the environment issucked into the work tool interior via an air intake 230 on one side of the tooland at least partly pushed out from the work tool interior via a first air outlet245 on the other side of the tool formed in a direction transversal from the airintake 230.

A portion of the air flow sucked into the work tool via the air inlet 230 is guidedvia an air conduit into the second part 120 where it is used to cool the electricalstorage device and optionally also cool portions of electrical control circuitry.With reference to, e.g., Figure 2B, this portion of the air flow is guideddownwards from the fan and then backwards in the tool towards the batterycompartment 150 before it exits the work tool via a second air outlet 250 formed in the second part 120 of the tool. lt is appreciated that the air flow can be directed also in the reverse direction ifthe fan is run in reverse. l.e., the air outlets 245, 250 can also be used to suck 12 cool air from the environment into the work tool 100, 200, and the air intake230 can be re-purposed to instead allow hot air to exit the work tool.

With reference to Figure 10A, the portion of the airflow 160 guided downwardsfrom the fan and then backwards in the tool also exits the work tool via a thirdair outlet 251 formed inside the battery compartment 151. This third outlet ismainly arranged to cool a battery received in the battery compartment 150.

Figures 3A and 3B illustrates some aspects of the disclosed work tool, whereinthe first part 110 comprises a thermally conductive cut-off arm 240 arrangedto support the circular cutting tool 130 on a first end of the cut-off arm 241, andto support the electric motor 140 by a support surface 330 at a second end ofthe cut-off arm 242 opposite to the first end 241. The motor 140 is thenarranged to drive the cutting tool via some type of drive arrangement, such asa belt drive or a combination of belt drive and geared transmission. The belt isnot shown in Figure 3A, only the belt pulley. The support surface 330represents a relatively large interfacing area between the motor 140 and thecut-off arm 240, which allows for a significant amount of heat transfer from themotor and into the cut-off arm material, at least if the electric motor comprisesa corresponding surface for interfacing with the support surface. This heat isthen dissipated from one or more cooling flanges 320 formed on the cut-offarm 240. Thus, the cut-off arm 240 comprises one or more cooling flanges 320arranged to dissipate heat away from the electric motor 140 via the supportsurface 330.

This heat transfer arrangement improves the heat dissipation from the motorsince the cooling air flow is more efficiently utilized to transport the heat away from the motor.

The more thermally conductive the cut-off arm is, the more efficient is the heatdissipation. According to some aspects, at least some parts of the cut-off armis formed in a material having a thermal conductivity property above 100 Wattsper meter and Kelvin (W/mK). For instance, at least some parts of the cut-offarm may be formed in aluminum, which has a thermal conductivity of about 237 W/mK. Iron or steel is another option which would provide the desired 13 thermal conductivity. The cut-off arm may also be formed in different materials,i.e., one highly thermally conductive material such as copper, magnesium oraluminum can be used for the cooling fianges and another material, such as cast iron or steel, to provide general structural support.

Optionally, the cut-off arm 240 is arranged to at least partially enclose theelectric motor 140, thereby protecting the motor and improving the air flow pastthe motor. According to some aspects, at least 30% of a volume of the electricmotor 140 is enclosed by the cut-off arm 240. Thus, the motor is optionallysignificantly embedded into the cut-off arm, thereby improving both structuralintegrity of the motor and cut-off arm assembly, as well as improving heattransport away from the electric motor.

The cut-off arm 240 and the electric motor 140 may also be at least partiallyintegrally formed. This means that some parts of the electric motor may beshared with the cut-off arm. For instance, a part of the cut-off arm 240 mayconstitute part of the electric motor housing, such as a motor gable facing thecut-off arm. The common part shared between the cut-off arm 240 and theelectric motor 140 may, e.g., be machined or molded. Also, optionally, theelectric motor axle may bear against a surface of the cut-off arm, to improvemechanical integrity. lt is noted that the feature of an at least partially integrally formed cut-off armand electric motor can be advantageously combined with the other featuresdisclosed herein but is not dependent on any of the other features disclosedherein. Thus, there is disclosed herein a cut-off arm 240 and electric motor 140assembly for a work tool 100, where the cut-off arm and the electric motor are at least partially integrally formed.

With reference to Figure 2B, the first part 1 10 optionally comprises a belt guard115 configured to enclose the interior space 340. As discussed above, aportion of the flow of cooling air is arranged to be guided 310 into the interiorspace 340, thereby increasing an air pressure in the belt guard 115 interiorspace 340 above an ambient air pressure level. The interior space 340 isdelimited on one side by the cut-off arm (discussed below in connection to 14 Figures 3A and 3B), and on the other side by the belt guard 115, whichassumes the function of a lid arranged to engage the cut-off arm to protect thedrive belt among other things. The belt guard 115 comprises an air outlet 245through which the flow of cooling air exits the interior space. This air outlet 245is configured with an area such that the air pressure in the belt guard 115interior space 340 increases above the ambient air pressure level by a desired amount.

The increase in air pressure in the interior space 340 means that a flow of airwill exit through all openings into the interior space 340, i.e., any cracks andthe like, and not just the air outlet 245. This in turn means that water, dust,debris and slurry will have to overcome this flow of air in order to enter into theinterior. Thus, accumulation of unwanted material inside the work tool is red uced _ Water inside the interior space 340 may cause the belt drive to slip and istherefore undesirable. The increase in air pressure in the belt guard 115interior space 340 means that less water is able to enter the interior space,which is an advantage. As a consequence, requirements on the belt can bereduced, such that, e.g., belts with a smaller number of ribs can be used.

As noted above, the portion of the flow of cooling air 160 guided from the firstpart 110 and into the second part 120 may pass via a bellows or other flexibleair flow conduit 170 arranged in-between the first 110 and the second 120 parts. Figure 4 shows an example of such bellows 10 in detail.

According to some aspects, the bellows 170 is associated with a Shoredurometer value, or Shore hardness, between 10-70, and preferably between50-60, measured with durometer type A according to DIN ISO 7619-1.

The bellows 170 optionally comprises a poka-yoke feature 410, 420. Thispoka-yoke feature comprises at least one protrusion 410, 420 configured toenter a corresponding recess formed in the first part 110 and/or in the secondpart 120, thereby preventing erroneous assembly of the bellows with the first110 and second 120 parts.

The bellows 170 also optionally comprises at least one edge portion 430, 440of increased thickness. Each such edge portion is arranged to enter acorresponding groove formed in the first part 110 or in the second part 120,thereby fixing the bellows 170 in relation to the first or second part similar to asai| |eech fitting into a mast. Figures 5 and 6 schematically i||ustrate a bellowsfitted onto the first and second parts, respectively, by the edge portions.

The bellows i||ustrated in Figure 4 is arranged with a shape that is symmetricabout a symmetry p|ane 450 parallel to an extension direction of the edgeportions 430, 440. Thus, advantageousiy, the bellows can be assembled withthe first and second parts independently of which side of the bellows that isfacing upwards. |.e., the bellows can be rotated 180 degrees about thesymmetry axis 460 and assembled with the first and second parts.

Figures 7A-C schematically i||ustrate aspects of the battery compartment 150,where the battery compartment comprises a battery lock mechanism 700. Thebattery lock mechanism comprises a locking member 710 rotatably supportedon a shaft 720. The locking member comprises a leading edge portion 750arranged to enter a recess 760 formed in the electrical energy source 220 tolock the electrical energy source in position, wherein the leading edge portion750 has an arcuate form with a curvature corresponding to that of a circlesegment with radius 740 corresponding to the distance from the leading edgeportion 750 to the center of the shaft 720, and wherein the recess 760 formedin the energy source 220 comprises a surface 770 arranged to engage theleading edge portion 750, wherein the surface 770 has an arcuate form tomatch that of the leading edge portion 750.

This way, as the electrical energy source 220 is received in the batterycompartment 150, the locking member is inactive, simply yielding to theelectrical energy source as it enters the compartment. This phase of insertingthe electrical energy source 220 into the compartment 150 by moving it in aninsertion direction 701 is schematically i||ustrated in Figures 7A and 7B. Thelocking member 710 then swings into the recess 760 where it prevents thebattery to be retracted from the battery compartment. The locking position is 16 illustrated in Figure 7C. Notably, the arcuate form of the leading edge portion750 allows the locking mechanism to be rotated out of the locking position withless resistance even if there is some friction between the leading edge portion 750 and the surface 770 arranged to engage the leading edge portion 750.

The locking member may be arranged spring biased towards the lockingposition, and operable by means of a lever or push-button mechanism,discussed below in connection to Figures 8 and 9.

According to some aspects, the battery compartment 150 comprises at leastone resilient member 780 arranged to urge the electrical energy source intothe locking position, i.e., urge the electrical energy source in a directionopposite that of the insertion direction 701. The resilient member 780, whencompressed by the electrical energy source, pushes onto the electrical energysource to repel it from the battery compartment 150. This pushing forceincreases the contact pressure between the leading edge portion 750 and thesurface 770 arranged to engage the leading edge portion 750, therebyimproving the holding effect on the electrical energy source.

According to an example, a user inserts a battery into the battery compartmentin an insertion direction. When the battery is inserted all the way, it contactsthe resilient member 780 and the locking member 710 enters the recess 760formed in the electrical energy source 220 to lock the electrical energy sourcein position. The resilient member, when compressed by the battery, pushesback in a direction opposite to the insertion direction. This pushing force fromthe resilient member increases a contact force between the leading edgeportion 750 of the locking member and the surface 770 arranged to engage the leading edge portion 750, to more securely hold the battery in position.

The resilient member 780 optionally comprises any of a resilient material member, a compression spring, and/or a leaf spring.

The resilient member 708 will also eject the electrical energy source 220 ashort distance from the battery compartment 150 when the electrical energysource is released by the locking mechanism 700. Thus, when the bush-buttonmechanism 810 is operated to release a battery, the battery is ejected from 17 the battery compartment 150, making it easier to grasp the battery and pull itout from the battery compartment.

Figure 7C schematically shows an example of such resilient members 780.The resilient members urge the electrical energy source in direction 702, butthe electrical energy source is prevented from moving in this direction by thelocking member 710 engaging the recess 760. The arrangement of resilientmember 780 and locking member 710 on opposite sides S1, S2, of theelectrical energy source 220 generates a twisting motion 795 or rotationmoment which further increases the holding effect by increasing frictionbetween battery and battery compartment wall, in a manner similar to a stuckcupboard or desk drawer. This further increase in holding effect reducesvibration by the battery since it is now held even more snugly in the battery compartment.

Figure 8 shows an example work tool 800 which comprises the battery lockmechanism 700. The locking member 710 is rotatably supported on a shaft720, where it is allowed to rotate about an axis 820 of rotation. A push-buttonmechanism 810 can be used by the operator to rotate the locking member 710such that it exits the recess, thereby allowing removal of the battery in direction702.

According to some aspects the locking member 710 is spring biased towardsthe locking position. Thus, as an electrical energy source 220 is inserted intothe recess 150, the locking member 710 snaps into the locking position. Thespring bias force can be overcome by the push-button mechanism 810 whenthe electrical energy source is to be removed from the battery compartment.

Figure 9 illustrates details of a battery lock mechanism 700 for a batterycompartment 150. This battery lock mechanism can be used with manydifferent types of tools, i.e., abrasive tools, grinders, chainsaws, drills, cut-oftools and the like. Thus, the battery lock mechanisms disclosed herein are notlimited to use with the cut-off tools discussed above in connection to Figures1-8. 18 The battery lock mechanism 700 shown in Figure 9 comprises a lockingmember 710 rotatably supported on a shaft 720 and optionally spring biasedinto a locking position as discussed above. The locking member comprises aleading edge portion 750 arranged to enter a recess 760 formed in theelectrical energy source 220 to lock the electrical energy source in position, asdiscussed above in connection to Figures 7A-C. The leading edge portion 750may have an arcuate form with a curvature corresponding to that of a circlesegment with radius 740 corresponding to the distance from the leading edgeportion 750 to the center of the shaft 720. The recess 760 formed in the energysource 220 comprises a surface 770 arranged to engage the leading edgeportion 750. This surface 770 has an arcuate form to match that of the leadingedge portion 750. Notably, the battery lock mechanism 700 illustrated in Figure9 comprises two locking members 710 separated by a distance. This doublearrangement of locking members improves robustness of the lock mechanism700.

Thus, as explained in connection to Figures 7A-C, an electrical energy sourcesuch as a battery can be inserted into the battery compartment in an insertiondirection 701, i.e., into the compartment 150 shown in Figure 9. At some pointthe locking member is able to enter into the locking position, i.e., it enters therecess 760. ln this position the battery is prevented from moving in a direction702 opposite to the insertion direction 701. However, it may rattle some andmay not be firmly secured. To improve the battery lock mechanism and tobetter hold the electrical energy source in position, one or more resilientmembers 780, such as compression springs or rubber bushings, are arrangedin the battery compartment 150 and/or on the electrical energy source to pushon the electrical energy source as it is inserted all the way into thecompartment. The pushing force increases a contact force between theleading edge portion 750 and the surface 770 configured to engage the leadingedge portion. This increased contact force increases friction to better hold theelectrical energy source in position.

According to some aspects, the at least one resilient member 780 and thebattery lock mechanism 700 are arranged at opposite sides S1, S2 of the 19 battery compartment 150, i.e., there is a plane 910 that divides the batterycompartment in two parts, where the resilient member 780 is comprised in onepart and the battery lock mechanism is comprised in the other part. This meansthat the resilient member or members push onto the electrical battery sourcefrom a direction to cause a twisting motion 795 or torque. This twisting motioncan be compared to a drawer which gets stuck in a cupboard or desk. Theelectrical energy source is then prevented from rattling and is more firmlysecured in the battery compartment 150.

Figures 10A and 10 B show an example work tool 1000 comprising a specialtype of fan 145. This fan comprises a member, preferably but not necessarilydiscoid shaped, arranged on the axle of the electric motor 140 which alsoconstitutes an axis of rotation of the fan. The member extends in a planeperpendicular to the axis of rotation and comprises two different types of fanportions. Afirst portion acts as an axial fan and pushes cooling airtransversally201 across the work tool 1000 to cool the electric motor 140. A second sectionof the fan acts as a radial fan, also known as a centrifugal fan, to push coolingair downwards and into the second part of the work tool in cooperation with afan scroll matched to the radial fan portion. The fan 145 is schematicallyillustrated in Figure 11 and an example of the fan is shown in Figure 12 wherethe direction of rotation 1130 and the axis of rotation 1140 have been indicated.Figure 11 also indicates the direction 1145 referred to as 'radially outwards'from the axis of rotation 1140.

Figure 10A shows an example tool where According to some aspects, theportion of the flow of cooling air 160 from the first part 110 and into the secondpart 120 is arranged to enter the electrical energy source 220 via a third outlet251 arranged inside the battery compartment 150. This connection to theelectrical energy source improves cooling efficiency by better cooling, e.g., thecells in a battery.

The fan 145 comprises an axial fan portion 1110 arranged peripherally on thefan 145, i.e., circumferentially along the fan disc border as shown in Figure 11and in Figure 12, and a radial fan portion 1120 arranged centrally on the fan 145, i.e., radially inwards from the axial fan portion as shown in Figures 11 and12. Thus, the axial fan portion is arranged radially outwards 1145 in theextension plane from the axis of rotation 1140. The axial fan portion 1110 isarranged to generate the flow of cooling air 1330 for cooling the electric motor140, and the radial fan portion 1120 is arranged to generate the portion of theflow of cooling air 160 from the first part 110 and into the second part 120 for cooling the electrical storage device.

Axial flow fans, or axial fans, have blades that force air to move parallel to theshaft about which the blades rotate, i.e., the axis of rotation. This type of fan isused in a wide variety of applications, ranging from small cooling fans forelectronics to the giant fans used in wind tunnels. The axial fan is particularlysuitable for generating large air flows in straight tube-line conduits, which is the case here when cooling the electric motor 140.

Radial fans, or centrifugal fans, uses the centrifugal power supplied from therotation of impellers to increase the kinetic energy of air/gases. When theimpellers rotate, the gas particles near the impellers are thrown off from theimpellers, then move into the fan housing wall. The gas is then guided to theexit by a fan scroll. A radial fan, compared to the axial fan, is better at pushingcooling air at a pressure passed air conduits with bends and narrow passages,which is the case for the air conduit passing into the second part and towards the battery compartment 150.

According to some aspects, the axial fan and the radial fan are formed as separate parts mounted on the same motor axle.

The radius of the radial fan may correspond to the radius of the electrical motor gable.

The relationship between the radius of the radial fan and the radius of the fan may be on the order of 50-70 percent.

Thus, advantageously, the fan illustrated in Figures 10-13 provide bothefficient motor cooling as well as efficient cooling of tool members in thesecond part, e.g., the control unit and the electrical energy source. This isachieved by providing two different types of fans on a single fan member. 21 Figure 10C shows a more detailed view of the part of the cut-off arm whichcomprises the one or more cooling flanges 320 arranged to dissipate heataway from the electric motor 140 via the support surface 330. The openings310 for letting air enter the interior space 340 discussed above can also beseen. The axiai fan portion 1110 pushes air past the motor and through theseho|es, thereby cooling the electric motor 140.

The fan 145 may optionally be assembled in a fan housing 1010 exemplifiedin Figure 13. The fan housing comprises at least one opening 1310 arrangedperipherally and radially outwards from the axis of rotation 1140 to receive theflow of cooling air 1330 from the axiai fan portion 1110 for cooling the electricmotor 140. The fan housing also comprises a fan scroll 1320 arranged centrallyin the housing to interface with the radial fan portion 1120 for guiding theportion of the flow of cooling air 160 from the first part 110 and into the secondpart 120 for cooling the electrical storage device.

Figure 13 also shows the grooves 1340 and the recesses 1350 for receivingthe bellows 170 with the edge portions 430 and the poka-yoke feature 410illustrated in Figure 4.

The fan discussed in connection to Figures 10A, B, 11, 12, and 13 is not onlyapplicable to the types of work tools disclosed herein. On the contrary, this fancan be used with advantage in any type of work tool where a first flow of coolingair and a second flow is desired. Thus, there is disclosed herein a fan 145 fora hand-held work tool 100, 200, 800, 1000. The fan 145 extends in a planeperpendicular to an axis of rotation of the fan 1140. The fan comprises an axiaifan portion 1110 arranged radially outwards 145 from a radial fan portion 1120arranged centrally on the fan 145 with respect to the axis of rotation 1140,wherein the axiai fan portion 1110 is arranged to generate a first flow of coolingair for cooling a first hand-held work tool member, and wherein the radial fanportion 1120 is arranged to generate a second flow of cooling air 160 for cooling a second hand-held work tool member. 22 Optionally, the axial fan portion 1110 has an annular shape centered on theaxis of rotation 1140, and wherein the radial fan portion 1120 has a discoidshape centered on the axis of rotation 1140.

There is also disclosed herein a hand-held work tool 1000 comprising the fandiscussed in connection to Figures 10-13, and a fan housing 1010. The fan145 is assembled in the fan housing 1010, which fan housing comprises atleast one opening 1310 arranged peripherally in the fan housing and radiallyoutwards from the axis of rotation 1140 of the fan 145 to receive the first flowof cooling airfrom the axial fan portion 1110 for cooling the first hand-held worktool member, the fan housing also comprises a fan scroll 1320 arrangedcentrally in the fan housing to interface with the radial fan portion for guidingthe second flow of cooling air 160 for cooling a second hand-held work tool member.

Claims

1. 1. A battery lock mechanism (700) for a battery compartment (150), thebattery lock mechanism comprising a locking member (710) rotatablysupported on a shaft (720), the locking member comprising a leading edgeportion (750) arranged to enter a recess (760) formed in the electrical energysource (220) to lock the electrical energy source in position, wherein theleading edge portion (750) has an arcuate form with a curvature correspondingto that of a circle segment with radius (740) corresponding to the distance fromthe leading edge portion (750) to the center of the shaft (720), and wherein therecess (760) formed in the energy source (220) comprises a surface (770)arranged to engage the leading edge portion (750), wherein the surface (770)has an arcuate form to match that of the leading edge portion (750).

2. The battery lock mechanism (700) according to claim 1, comprising atleast one resilient member (780) arranged to urge the electrical energy sourceinto the locking position, wherein the at least one resilient member (780) andthe locking member (710) are arranged at opposite sides (S1, S2) of thebattery compartment (150).

3. The battery lock mechanism (700) according to any previous claim,wherein the resilient member (780) comprises any of a resilient materialmember, a rubber bushing, a compression spring, and/or a leaf spring.

4. The battery lock mechanism (700) according to any previous claim,wherein the locking member (710) is spring biased towards the lockingposition, and operable by means of a lever or push-button mechanism (810).

5. The battery lock mechanism (700) according to any previous claim,comprising a plurality of locking members (710) arranged spaced apart by adistance, wherein the at least one resilient member (780) and the lockingmembers (710) are arranged at opposite sides (S1, S2) of the batterycompartment (150).

6. A hand-held work tool (100, 200, 800, 1000) comprising the battery lockmechanism (700) according to any previous claim.