Handheld power tools

Abstract

A hand-held electric cutting tool (100, 200, 800, 1000, 1900) comprises a first part (110) and a second part (120) arranged in vibration isolation from each other, the first part (110) comprising an arm (116) arranged to support a cutting disc (130) and a motor (140) arranged to drive the cutting disc, the second part (120) comprising a front handle (190) and a rear handle (195) for operating the cutting tool and a battery compartment (150) for holding an electrical storage device (220, 1800) such as a battery, the electrical storage device being arranged to supply power to the motor (140), wherein one or more damping members (170, 1910) are arranged between the first part (110) and the second part (120), wherein at least one damping member (170, 1910) is formed of an elastic material associated with a damping coefficient.

Description

Technical Field

[0001] The present disclosure relates to a powered handheld work equipment, such as a cut-off tool and a saw for cutting concrete and stone. Background Art

[0002] Handheld work tools used for cutting and / or grinding hard materials such as concrete and stone include powerful electric motors to provide the power required to process the hard materials. These motors generate a lot of heat and therefore need to be cooled to prevent overheating. Electric work tools generate heat through the motor as well as through the battery and control electronics. An effective method for cooling such work tools is needed.

[0003] Work tools also typically generate vibrations that may be harmful or at least cause discomfort to the operator of the tool. It is desirable to protect the operator from prolonged exposure to strong vibrations.

[0004] The environment in which these types of tools are used is often harsh. The work tools are exposed to water, dust, debris, and mud, which can adversely affect tool performance. For example, mud can accumulate inside the work tool, where it ultimately causes the tool to fail. It is desirable to prevent the accumulation of dust and mud inside the work tool.

[0005] Ease of operation is particularly important for work tools used on construction sites. For electric work tools, it is desirable to be able to perform field battery changes in an efficient and convenient manner, wherein the battery is easily inserted into the work tool, wherein the battery is snugly retained in the work tool, and wherein the battery is easily released from the work tool.

[0006] In summary, there are challenges associated with handheld work tools. Summary of the invention

[0007] An object of the present disclosure is to provide an improved handheld work tool that solves the above-mentioned problems.

[0008] This object is at least partially achieved by a hand-held electric cutting tool, the hand-held electric cutting tool comprising a first part and a second part arranged in vibration isolation from each other, the first part comprising an arm arranged to support a cutting disk and a motor arranged to drive the cutting disk. The second part comprises a front handle and a rear handle for operating the cutting tool and a battery compartment for holding an electrical storage device such as a battery, the electrical storage device being arranged to supply power to the motor. Notably, one or more damping members are arranged between the first part and the second part, wherein at least one damping member is formed of an elastic material associated with a damping coefficient.

[0009] In this way, the tendency to create oval cutting discs during operation is mitigated.Further advantages are achieved through the disclosure set forth herein.

[0010] The main vibration generating components of the working tool are included in the first part. Therefore, by vibrationally isolating the first part from the second part, the amount of vibration transmitted to the second part is significantly reduced. The second part may, for example, include a front handle and a rear handle, which are then vibrationally isolated from the vibration source in the first part. Due to the reduced vibration, the operator can use the tool for longer periods of time and with an increased comfort level.

[0011] Further advantages are achieved by the features set out in the disclosure.

[0012] In general, unless explicitly defined otherwise herein, all terms used in the claims will be interpreted according to their ordinary meaning in the technical field. Unless explicitly stated otherwise, all references to "one / an / the element, device, part, means, step, etc." will be openly interpreted as referring to at least one instance of the element, device, part, device, step, etc. Unless explicitly stated otherwise, the steps of any method disclosed herein do not have to be performed in the exact order disclosed. Other features and advantages of the present invention will become apparent when studying the attached claims and the following description. Those skilled in the art recognize that, without departing from the scope of the present invention, different features of the present invention can be combined to create embodiments other than those described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present disclosure will now be described in more detail with reference to the accompanying drawings, in which

[0014] Figure 1 An example working tool is shown;

[0015] FIG. 2A to FIG. 2C A view showing another example working tool;

[0016] FIG. 3A to FIG. 3B A view showing a work tool support arm;

[0017] Figures 4 to 6 A bellows for directing airflow is shown;

[0018] FIG. 7A to FIG. 7C The locking mechanism is schematically shown;

[0019] Figure 8 An example work tool having a battery locking mechanism is shown;

[0020] Fig. 9 The details of the battery locking mechanism are schematically shown;

[0021] FIG. 10A to FIG. 10C A view showing an example working tool;

[0022] Fig.11 The fan is schematically shown;

[0023] Fig.12 An example fan for a work tool is shown;

[0024] Fig.13 An example fan housing is shown;

[0025] FIG. 14A to FIG. 14C Details of the work tool support arm are shown;

[0026] Fig.15 A drive device for driving a circular cutting tool is shown;

[0027] Fig.16A The rear handle section with water hose connection is shown;

[0028] FIG. 16B to FIG. 16C Details of the water hose connector arrangement are shown;

[0029] FIG. 17A to FIG. 17B Details of the battery compartment are shown;

[0030] 18A to 18C A battery is shown for insertion into the battery compartment;

[0031] Fig.19 A cut-off tool is schematically shown;

[0032] Fig. 20 Details of the cutting tool are shown;

[0033] Fig.21 An example damping member is shown;

[0034] Fig. 22 Another example damping member is shown;

[0035] Fig.23 shows cooling airflow through a portion of a cutting tool;

[0036] Fig.24 The cooling airflow is schematically shown;

[0037] Fig.25 The mass distribution of the work tool is schematically shown. DETAILED DESCRIPTION

[0038] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain aspects of the invention are shown. However, the present invention may be implemented in many different forms and should not be construed as limited to the embodiments and aspects set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. Throughout the specification, the same numerals represent the same elements.

[0039] It should be understood that the present invention is not limited to the embodiments described herein and shown in the drawings; rather, those skilled in the art will recognize that many changes and modifications are possible within the scope of the appended claims.

[0040] Figure 1 A handheld work tool 100 is shown. Figure 1 The working tool 100 in the embodiment includes a rotatable circular cutting tool 130, but the technology disclosed herein can also be applied to other cutting tools, such as chain saws, core drills, etc. The motor 140 is arranged to drive the cutting tool. This motor is powered by an energy storage device, which is arranged to be held in a battery compartment 150.

[0041] The electric motor generates a large amount of heat during operation. In order to prevent the motor from overheating, a fan 145 is arranged to be driven by the motor 140. This fan can be attached to the motor shaft directly, or attached to the motor shaft through some means of transmission. The fan generates an air flow, which carries heat away from the motor, thereby cooling the motor.

[0042] The working tool 100 is arranged to be held by a front handle 190 and a rear handle 195, and is operated in a known manner by a trigger 196. Since excessive vibrations may cause discomfort to an operator using the working tool 100, it is desirable to minimize vibrations in the handles and triggers. Excessive vibrations may also reduce the life of tool components (such as cable connections and electronic devices). In order to reduce these vibrations, the working tool 100 includes a first part 110 and a second part 120 that are arranged to be vibrationally isolated from each other. The first part 110 includes an interface for holding a cutting tool 130, and also includes a motor 140 arranged to drive the cutting tool. Therefore, the first part includes the main vibration generating element of the working tool.

[0043] Notably, second portion 120 includes handles 190, 195 and trigger 196, and is thus the portion that an operator interacts with work tool 100. Second portion 120 also includes a battery compartment 150 for holding electrical storage, and control electronics for controlling various operations of work tool 100.

[0044] Since the vibrations generated in the first portion 110 are not transmitted to the second portion 120, or at least not in a significant amount, the operator of the device 100 will not be subjected to vibrations, which is advantageous because he or she may be able to work for longer periods of time in more comfortable working conditions.

[0045] Vibration is usually measured in m / s 2 The unit is measured and it is expected that the tool vibration in the front and rear handles will be limited to 2.5m / s 2 Tool vibration, guidelines for limiting tool vibration, and the measurement of tool vibration are discussed below in "Vibrators - Swedish Work Environment Administration regulations on vibration and general recommendations on the application of the regulations" (Swedish Work Environment Administration, AFS 2005:15).

[0046] According to some aspects, work tool 100 includes first portion 110 and second portion 120 arranged to be vibrationally isolated from each other by a vibration isolation system arranged to limit front handle vibration and rear handle vibration to less than 2.5 m / s 2 The value of .

[0047] The cooling air duct is arranged to direct a portion of the cooling airflow 160 from the first portion 110 into the second portion 120 for cooling the electrical storage device. This means that the fan 145 is used to cool both the motor 140 and the electrical energy source, which is an advantage as only a single fan is required.

[0048] Here, a duct is a passage arranged to guide a flow such as an air flow. The cooling air duct may be formed as part of an interior space enclosed by the work tool body portion, or as a hose of other types of ducts, or as a combination of different types of ducts.

[0049] Any control electronics included in the second portion 120 may also be arranged to be cooled by the portion of the cooling airflow 160 directed from the first portion 110 and into the second portion 120 . Figure 1 A cooling flange 180 associated with such control electronics is schematically shown, which cooling flange 180 is optional, i.e. this portion of the cooling air flow can be used to directly cool the control unit, in which case the control unit constitutes the cooling flange. Thus, optionally, the portion of the cooling air flow 160 entering the second portion 120 from the first portion 110 is arranged to pass through a cooling flange 180 associated with the control unit of the handheld working tool 100.

[0050] At least in part because the first and second portions are arranged in vibration isolation from one another, effectively directing a portion of the air 160 from the first portion and into the second portion can be a challenge. Some aspects of the disclosed work tool address this challenge by providing a bellows or some other type of flexible airflow duct between the first and second portions to direct the portion of the air from the fan 145 toward the battery compartment 150. These bellows 170 will be described below in conjunction with Figures 4 to 6 A bellows is sometimes also referred to as a flexible cover, a convolution, a corrugation, or a machine direction cover. A hose formed of a flexible material may be used in place of the bellows.

[0051] In conclusion, Figure 1 A handheld working tool 100 is schematically shown comprising a first portion 110 and a second portion 120 arranged vibrationally isolated from each other. According to some aspects, the first portion 110 is vibrationally isolated from the second portion 120 by one or more resilient elements.

[0052] Handheld working tools can be Figure 1 The cutting tool shown is a chain saw or other working tool for cutting hard materials. The first part comprises an interface for holding the cutting tool 130 and a motor 140 arranged to drive the cutting tool. The drive means may, for example, comprise a belt drive or a combination of a belt drive and a gear drive. The motor 140 is arranged to drive a fan 145, which is configured to generate a cooling air flow for cooling the motor 140. The fan may, for example, be directly connected to the motor shaft, or it may be indirectly connected to the motor shaft via some transmission or drive means, such as a belt drive or a gear drive.

[0053] The second part 120 includes a battery compartment 150 for holding an electrical storage device arranged to power the electric motor 140, and the cooling air duct is arranged to direct a portion of the cooling air flow 160 from the first part 110 and into the second part 120 to cool the electrical storage device. The electrical energy source may be a battery, or some type of fuel cell, etc.

[0054] FIG. 2A to FIG. 2C Different views of an example handheld working tool 200 arranged to hold a cutting tool via a cutting tool interface 260 are shown. The resilient element separating the first portion 110 from the second portion 120 is here a compression spring 210. However, as described above, some types of resilient material members, such as rubber bushings, may also be used as an alternative to or in combination with the spring. Leaf springs may also be an option for vibrationally isolating the first portion 110 from the second portion 120.

[0055] Figure 2BA holder 270 for an additional blade bushing is shown. When the cutting disc reaches the center hole in the blade, it can have different sizes. Some blade holes are 20 mm wide, while some other holes are 25.5 mm wide. There are even some markets where a 30.5 mm center hole in a blade is common. In order to allow the use of different types of blades with different sizes in the center blade hole, the handheld working tool 200 includes a holder 270 arranged on the working tool body for holding a blade bushing. This additional blade bushing is preferably of different size compared to the blade bushing mounted to connect to the cutting tool interface 260.

[0056] Figure 2A An example electrical storage device 220 (here a battery) is shown mounted in the battery compartment 150. This battery may be held in place by a battery locking mechanism, which will be described below in conjunction with FIG. 7A to FIG. 7C , Figure 8 and Fig. 9 Other types of electrical energy sources that can be used with the devices and techniques disclosed herein include, for example, fuel cells, supercapacitors, and the like.

[0057] According to some aspects, the cooling air flow for cooling the motor 140 extends through the handheld working tool transversely 230, 245, 201 relative to the extension plane of the circular cutting tool 130. Here, reference is made to Figure 2C , transverse direction should be interpreted as relative to the extension direction 202 of the working tool extending from the rear handle 195 toward the cutting tool and relative to the extension plane of the cutting tool 130 (which is in Figure 2C Air from the environment is drawn into the interior of the work tool via an air inlet 230 on one side of the tool and is at least partially pushed out of the interior of the work tool via a first air outlet 245 on the other side of the tool, which is formed in a direction transverse to the air inlet 230.

[0058] A portion of the airflow drawn into the work tool via the air inlet 230 is directed via the air duct into the second portion 120 where it is used to cool the electrical storage device and optionally also portions of the electrical control circuitry. Figure 2B This portion of the airflow is directed downwardly from the fan and then rearwardly within the tool toward the battery compartment 150 before exiting the work tool via a second air outlet 250 formed in the second portion 120 of the tool.

[0059] It should be understood that the airflow can also be directed in the opposite direction if the fan is run in reverse. That is, the air outlets 245, 250 can also be used to draw cool air from the environment into the work tool 100, 200, and the air inlet 230 can be repurposed to allow hot air to leave the work tool instead.

[0060] refer to Fig. 10A Part of the airflow 160 directed downwardly from the fan and then rearwardly in the tool also leaves the work tool via a third air outlet 251 formed inside the battery compartment 151. This third outlet is primarily arranged to cool the batteries housed in the battery compartment 150.

[0061] Figure 3A and Figure 3B Some aspects of the disclosed work tool are shown, wherein the first portion 110 includes a thermally conductive support arm 240 arranged to support a circular cutting tool 130 at a first end 241 of the support arm, and to support a motor 140 via a support surface 330 at a second end 242 of the support arm opposite the first end 241. The motor 140 is then arranged to drive the cutting tool via some type of drive arrangement, such as a belt drive or a combination of a belt drive and a gear drive. The belt is Figure 3A 330, only the pulley is shown. The support surface 330 presents a relatively large interface area between the motor 140 and the support arm 240, which allows a large amount of heat transfer from the motor to the support arm material, at least in the case where the motor includes a corresponding surface for interfacing with the support surface. This heat is then dissipated from one or more cooling flanges 320 formed on the support arm 240. Therefore, the support arm 240 includes one or more cooling flanges 320, which are arranged to dissipate heat away from the motor 140 via the support surface 330.

[0062] The support arm 240 is the arm of the cutting tool, which may equivalently be referred to as the cutting arm 240 .

[0063] This heat transfer device improves the removal of heat from the motor because the cooling air flow is more effectively used to transport heat away from the motor.

[0064] The higher the thermal conductivity of the support arm, the more effective the heat dissipation. According to some aspects, at least some portions of the support arm are formed of a material having a thermal conductivity of more than 100 watts per meter Kelvin (W / mK). For example, at least some portions of the support arm can be formed of aluminum, which has a thermal conductivity of approximately 237 W / mK. Iron or steel is another option to provide the desired thermal conductivity. The support arm can also be formed of different materials, i.e., a high thermal conductivity material, such as copper, magnesium, or aluminum, can be used for cooling the flange, and another material, such as cast iron or steel, is used to provide general structural support.

[0065] FIG. 14A to FIG. 14C and Fig.15 Details of an example support arm 240 are shown, the support arm being arranged to support the circular cutting tool 130 on a first end 241 of the support arm and to support the motor 140 via a support surface 330 at a second end 242 of the support arm opposite the first end 241 . Fig.14A A view of the support arm 240 and the interior space 340 described above is shown. Fig. 14B shows a first cross-sectional view along line AA, Fig. 14C A second cross-sectional view along line BB is shown.The electric motor 140 comprises a motor shaft extending through a motor housing 141 in a known manner.

[0066] The first end 142 of the shaft is arranged to hold a pulley for driving the circular cutting tool 130 . Fig.15 A view of the support arm 240 is shown with the drive pulley and drive belt in place to drive the circular cutting tool 130 .

[0067] The second end 143 of the motor shaft is arranged to drive a fan 145 . Fig. 14B The example fan 145 shown is a conventional axial fan. Figures 11 to 13 Another more advanced example of fan 145 is discussed.

[0068] Optionally, the support arm 240 is arranged to at least partially surround the motor 140, thereby protecting the motor and improving the cooling efficiency of the airflow 1330 passing through the motor. To this end, the support arm 240 includes a cup-shaped recess, such as in Fig. 10C 330, wherein the support surface 330 forms the bottom of the recess, and the cylindrical wall 350 extends from the periphery of the support surface 330 to surround the motor housing 141 of the motor 140 when the motor is supported on the support surface 330. The motor 140 is arranged to be securely bolted to the support surface 330 via the bolt holes 335, thereby ensuring good heat conduction and mechanical integrity between the motor 140 and the support arm 240. A narrow slot is formed between the cylindrical wall 350 and the motor 140, that is, the recess wall 350 is radially spaced apart from the motor housing. This narrow slot is arranged to guide a cooling airflow 1330 from the fan 145 through the motor 140. The airflow 1330 extends laterally from the fan 145 through the support arm 240 to cool the motor 140. The cooling airflow 1330 then passes through the opening 310 and enters the interior space 340, and then passes through Figure 2B A first air outlet 245 is shown exiting.

[0069] According to some aspects, at least 30% of the volume of motor 140 (i.e., the volume of the motor including its housing 141) is enclosed by support arm 240. This means that cylindrical wall 350 extends a distance 144 from support surface 330 to enclose at least 30% of the volume of motor housing 141. Thus, the motor is optionally significantly embedded in the support arm, or even as FIG. 14A to FIG. 14C As shown, it is fully embedded, thereby improving the structural integrity of the motor and support arm assembly and improving heat transfer away from the motor. Cooling of the motor 140 is also improved by the slot formed between the cylindrical wall and the motor housing, which cooperates with the thermally conductive support arm and cooling flange to effectively cool the motor.

[0070] The support arm 240 and the motor 140 may also be at least partially integrally formed. This means that some components of the motor 140 may be shared with the support arm 240. For example, a portion of the support arm 240 may constitute a portion of the motor housing, such as a motor cover facing the support arm. Common components shared between the support arm 240 and the motor 140 may, for example, be machined or molded. Moreover, optionally, the motor shaft may abut against a surface of the support arm to improve mechanical integrity.

[0071] It should be noted that the features of the at least partially integrally formed support arm and motor can be advantageously combined with other features disclosed herein, but are independent of any other features disclosed herein. Thus, a support arm 240 and motor 140 assembly for a work tool 100 is disclosed herein, wherein the support arm and motor are at least partially integrally formed.

[0072] refer to Figure 2B , the first portion 110 optionally includes a hood 115 configured to surround an interior space 340. As described above, a portion of the cooling airflow is arranged to be directed into the interior space 340, thereby increasing the air pressure in the interior space 340 of the hood 115 to above the ambient air pressure level. The interior space 340 is supported on one side by a support arm (hereinafter referred to as Figure 3A and Figure 3B The belt cover 115 is delimited on one side by the support arm 340 and on the other side by the belt cover 115, which assumes the function of a cover arranged to engage the support arm to protect the drive belt therein. The belt cover 115 includes an air outlet 245 through which the cooling air flow leaves the interior space. This air outlet 245 is configured to have an area so that the air pressure in the interior space 340 of the belt cover 115 is increased by a desired amount above the ambient air pressure level.

[0073] The increase in air pressure in the interior space 340 means that the airflow will exit through all openings in the interior space 340, i.e. any cracks etc., rather than just the air outlet 245. This in turn means that water, dust, debris and mud will have to overcome this airflow in order to enter the interior. Thus, the accumulation of undesirable material within the work tool is reduced.

[0074] Water in the inner space 340 may cause the drive belt to slip and is therefore undesirable. The increase in air pressure in the inner space 340 of the belt cover 115 means that less water can enter the inner space, which is an advantage. Therefore, the requirements on the belt can be reduced, so that, for example, a belt with a smaller number of ribs can be used.

[0075] As described above, a portion of the cooling airflow 160 directed from the first portion 110 and into the second portion 120 may pass via a bellows or other flexible airflow conduit 170 disposed between the first portion 110 and the second portion 120 . Figure 4 An example of such a bellows 10 is shown in detail.

[0076] According to some aspects, the Shore durometer value or Shore hardness associated with bellows 170 is between 10-70, preferably between 50-60, as measured using a Type A durometer according to DIN ISO 7619-1.

[0077] The bellows 170 optionally includes a poka-yoke feature 410, 420. The poka-yoke feature includes at least one protrusion 410, 420 configured to enter a corresponding recess formed in the first portion 110 and / or the second portion 120, thereby preventing incorrect assembly of the bellows with the first portion 110 and the second portion 120.

[0078] The bellows 170 also optionally includes at least one edge portion 430, 440 of increased thickness. Each such edge portion is arranged to enter a corresponding groove formed in the first part 110 or in the second part 120, thereby fixing the bellows 170 relative to the first part or the second part similar to a sail leech fitted into a mast. Figure 5 and Figure 6 A bellows is schematically shown which is fitted to a first part and a second part respectively via edge portions.

[0079] Figure 4 The bellows shown is arranged to have a symmetrical shape about a symmetry plane 450, which is parallel to the extension direction of the edge portions 430, 440. Therefore, advantageously, the bellows can be assembled with the first part and the second part regardless of which side of the bellows faces upward. That is, the bellows can be rotated 180 degrees around the symmetry axis 460 and assembled with the first part and the second part.

[0080] FIG. 7A to FIG. 7C Aspects of a battery compartment 150 are schematically shown, wherein the battery compartment comprises a battery locking mechanism 700. The battery locking mechanism comprises a locking member 710 rotatably supported on a shaft 720. The locking member comprises 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 place, wherein the leading edge portion 750 has an arcuate shape having a curvature corresponding to the curvature of a circle segment having a 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 electrical energy source 220 comprises a surface 770 arranged to engage the leading edge portion 750, wherein the surface 770 has an arcuate shape matching the arcuate shape of the leading edge portion 750.

[0081] Thus, when the electrical energy source 220 is housed in the battery compartment 150, the locking member is inactive and simply yields to the electrical energy source when the electrical energy source enters the compartment. Fig. 7A and Figure 7B This stage of insertion of the electrical energy source 220 into the compartment 150 by moving it in the insertion direction 701 is schematically shown in FIG. The locking member 710 is then swung into the recess 760, where it prevents the battery from being withdrawn from the battery compartment. Figure 7C The locked position is shown in . Notably, even though there is some friction between the leading edge portion 750 and the surface 770 arranged to engage the leading edge portion 750, the arcuate shape of the leading edge portion 750 allows the locking mechanism to be rotated out of the locked position with less resistance.

[0082] The locking member may be arranged to be spring biased towards the locked position and may be operated by a lever or button mechanism, as described below in conjunction with Figure 8 and Fig. 9 discussed.

[0083] It will be appreciated that there may be any number of locking members arranged in the battery compartment in the manner described above, ie anywhere from a single locking member to a plurality of locking members.

[0084] According to some aspects, the battery compartment 150 comprises at least one resilient member 780 arranged to push the electrical energy source into the locked position, i.e., to push the electrical energy source in a direction opposite to the insertion direction 701. When compressed by the electrical energy source, the resilient member 780 pushes onto the electrical energy source to repel it from the battery compartment 150. This pushing force increases the contact pressure between the leading edge portion 750 and the surface 770 arranged to engage the leading edge portion 750, thereby improving the retention of the electrical energy source.

[0085] According to one example, a user inserts a battery into the battery compartment in the insertion direction. When the battery is fully inserted, it contacts the resilient member 780, and the locking member 710 enters a recess 760 formed in the electrical energy source 220 to lock the electrical energy source in place. When compressed by the battery, the resilient member pushes back in a direction opposite to the insertion direction. This thrust from the resilient member increases the contact force between the leading edge portion 750 of the locking member and the surface 770 arranged to engage the leading edge portion 750 to more securely hold the battery in place.

[0086] The elastic member 780 optionally includes any one of an elastic material member, a compression spring and / or a leaf spring.

[0087] When the electrical energy source is released by the locking mechanism 700, the resilient member 780 will also eject the electrical energy source 220 a short distance from the battery compartment 150. Thus, when the button mechanism 810 is operated to release the battery, the battery is ejected from the battery compartment 150, making it easier to grab the battery and pull it out of the battery compartment.

[0088] Figure 7C An example of such a resilient member 780 is schematically shown. The resilient member pushes the electrical energy source in direction 702, but the electrical energy source is prevented from moving in this direction by the locking member 710 engaging the recess 760. The arrangement of the resilient member 780 and the locking member 710 on the opposite sides S1, S2 of the electrical energy source 220 creates a torsional motion 795 or rotational moment, which further increases the retention effect by increasing the friction between the battery and the battery compartment wall in a manner similar to a stuck cabinet or desk drawer. This further increase in retention effect reduces vibration of the battery because the battery is now more snugly held in the battery compartment.

[0089] Figure 8 An example work tool 800 is shown including a battery locking mechanism 700. Locking member 710 is rotatably supported on shaft 720, wherein it is allowed to rotate about rotation axis 820. An operator can use button mechanism 810 to rotate locking member 710 so that it leaves the recess, thereby allowing the battery to be removed in direction 702.

[0090] According to some aspects, the locking member 710 is spring biased toward the locked position. Thus, when the electrical energy source 220 is inserted into the recess 150, the locking member 710 snaps into the locked position. When the electrical energy source is to be removed from the battery compartment, the button mechanism 810 can overcome the spring bias.

[0091] Fig. 9Details of a battery locking mechanism 700 for the battery compartment 150 are shown. Such a battery locking mechanism can be used with many different types of tools (i.e., grinding tools, grinders, chain saws, drills, cutting tools, etc.). Therefore, the battery locking mechanism disclosed herein is not limited to use in conjunction with the above Figures 1 to 8 Used together with the cutting tool discussed.

[0092] Fig. 9 The illustrated battery locking mechanism 700 includes a locking member 710 that is rotatably supported on an axle 720 as described above and is optionally spring biased into a locked position. The locking member includes a leading edge portion 750 that is arranged to enter a recess 760 formed in the electrical energy source 220 to lock the electrical energy source in place, as described above in conjunction with FIG. 7A to FIG. 7C As discussed. The leading edge portion 750 may have an arcuate shape, the curvature of which corresponds to the curvature of a circle segment, the radius 740 of the circle segment corresponding to the distance from the leading edge portion 750 to the center of the shaft 720. The recess 760 formed in the electrical energy source 220 includes a surface 770 arranged to engage the leading edge portion 750. This surface 770 has an arcuate shape that matches the arcuate shape of the leading edge portion 750. It is worth noting that Fig. 9 The battery locking mechanism 700 shown includes two locking members 710 separated by a certain distance. This dual arrangement of locking members improves the robustness of the locking mechanism 700.

[0093] Therefore, if combined FIG. 7A to FIG. 7C As explained, an electrical energy source such as a battery can be inserted into the battery compartment in an insertion direction 701, i.e., into the Fig. 9 1. In the compartment 150 shown. At a certain moment, the locking member is able to enter the locking position, that is, it enters the recess 760. In this position, the battery is prevented from moving in the direction 702 opposite to the insertion direction 701. However, it may make some clicking sounds and may not be firmly fixed. In order to improve the battery locking mechanism, and in order to better keep the electrical energy source in place, one or more elastic members 780 (such as compression springs or rubber bushings) are arranged in the battery compartment 150 and / or on the electrical energy source to push the electrical energy source when the electrical energy source is fully inserted into the compartment. The thrust increases the contact force between the leading edge portion 750 and the surface 770 configured to engage the leading edge portion. This increased contact force increases friction to better keep the electrical energy source in place.

[0094] According to some aspects, the at least one resilient member 780 and the battery locking mechanism 700 are arranged at opposite sides S1, S2 of the battery compartment 150, i.e., there is a plane 910 that divides the battery compartment into two parts, wherein the resilient member 780 is included in one part and the battery locking mechanism is included in the other part. This means that one or more resilient members push against the battery source from one direction to cause a twisting motion 795 or torque. This twisting motion can be compared to a drawer stuck in a cabinet or desk. Thus, the electrical energy source is prevented from making a rattling sound and is more securely fixed in the battery compartment 150.

[0095] Fig. 10A and Fig. 10B An example work tool 1000 is shown that includes a special type of fan 145. This fan includes a member, which is preferably but not necessarily disc-shaped, which is arranged on the shaft of the motor 140, which also constitutes the axis of rotation of the fan. The member extends in a plane perpendicular to the axis of rotation and includes two different types of fan parts. The first part acts as an axial fan and pushes cooling air laterally 201 through the work tool 1000 to cool the motor 140. The second part of the fan acts as a radial fan, also called a centrifugal fan, to cooperate with the fan scroll (scroll) that is matched to the radial fan part to push the cooling air downward and into the second part of the work tool. Fig.11 The fan 145 is schematically shown in FIG. Fig.12 An example of a fan is shown in , where the direction of rotation 1130 and the axis of rotation 1140 have been indicated. Fig.11 A direction 1145 , referred to as “radially outward” from the axis of rotation 1140 , is also indicated.

[0096] Fig. 10A An example tool is shown in which, according to some aspects, a portion of the cooling airflow 160 from the first portion 110 and entering the second portion 120 is arranged to enter the electrical energy source 220 via a third outlet 251 arranged inside the battery compartment 150. This connection to the electrical energy source improves cooling efficiency by better cooling, for example, the cells in the battery.

[0097] The fan 145 includes an axial fan portion 1110 which is arranged on the fan 145 along the periphery, that is, Fig.11 and Fig.12 As shown, the fan is arranged circumferentially along the disc-shaped boundary of the fan; and a radial fan portion 1120, which is centrally arranged on the fan 145, that is, as Fig.11 and Fig.12The axial fan portion is shown arranged radially inwardly from the axial fan portion. Thus, the axial fan portion is arranged radially outwardly 1145 from the axis of rotation 1140 in the extended plane. The axial fan portion 1110 is arranged to generate a cooling airflow 1330 for cooling the electric motor 140, and the radial fan portion 1120 is arranged to generate a portion of the cooling airflow 160 from the first portion 110 and into the second portion 120 for cooling the electrical storage device.

[0098] An axial flow fan, or axial fan, has blades that force air to move parallel to an axis about which the blades rotate, i.e., the axis of rotation. This type of fan is used in a variety of applications, from small cooling fans for electronics to giant fans used in wind tunnels. Axial fans are particularly well suited to creating large airflows in ducts with straight runs of tubing, which is the case when cooling electric motors 140.

[0099] A radial fan or centrifugal fan uses the centrifugal power provided by the rotation of the impeller to increase the kinetic energy of the air / gas. As the impeller rotates, gas particles near the impeller are thrown off the impeller and then move into the fan housing wall. The gas is then directed to the outlet through the fan vortex. Compared to an axial fan, a radial fan is better at pushing cooling air under pressure through an air duct having a bend and a narrow passage, which is the case where the air duct enters the second portion and toward the battery compartment 150.

[0100] According to some aspects, the axial fan and the radial fan are formed as separate components mounted on the same motor shaft.

[0101] The radius of the radial fan may correspond to the radius of the motor cover.

[0102] The relationship between the radius of a radial fan and the radius of the fan may be of the order of 50%-70%.

[0103] Therefore, advantageously, FIG. 10 to FIG. Fig.13 The fan shown provides effective cooling of the motor as well as effective cooling of the tool components in the second part, such as the control unit and the electrical energy source. This is achieved by providing two different types of fans on a single fan component.

[0104] Fig. 10C A more detailed view of a portion of the support arm is shown, the portion including one or more cooling flanges 320 arranged to dissipate heat from the motor 140 via the support surface 330. Also visible are the aforementioned openings 310 for air to enter the interior space 340. The axial fan portion 1110 forces air past the motor and through these apertures, thereby cooling the motor 140.

[0105] The fan 145 may be optionally assembled in Fig.13The fan housing 1010 is illustrated in FIG. The fan housing includes at least one opening 1310, which is arranged radially outward from the rotation axis 1140 along the periphery to receive a cooling airflow 1330 from the axial fan portion 1110 for cooling the motor 140. The fan housing also includes a fan vortex 1320, which is centrally arranged in the housing to connect with the radial fan portion 1120, for guiding a portion of the cooling airflow 160 from the first portion 110 into the second portion 120 to cool the electric storage device.

[0106] Fig.13 Also shown are grooves 1340 and recesses 1350 for receiving bellows 170 having Figure 4 The edge portion 430 and the error-proofing feature 410 are shown.

[0107] Combination Fig. 10A , Fig. 10B , Fig.11 , Fig.12 and Fig.13 The fan discussed is not only applicable to the type of working tool disclosed in this article. On the contrary, this fan can be advantageously used in any type of working tool that expects a first cooling airflow and a second cooling airflow. Therefore, a fan 145 for a handheld working tool 100, 200, 800, 1000 is disclosed herein. The fan 145 extends in a plane perpendicular to the axis of rotation of the fan 1140. The fan 145 includes an axial fan portion 1110, which is arranged radially outward from a radial fan portion 1120 centrally arranged on the fan 145 relative to the axis of rotation 1140, wherein the axial fan portion 1110 is arranged to generate a first cooling airflow for cooling a first handheld working tool component, and wherein the radial fan portion 1120 is arranged to generate a second cooling airflow 160 for cooling a second handheld working tool component.

[0108] Optionally, the axial fan portion 1110 has an annular shape centered on the rotation axis 1140 , and wherein the radial fan portion 1120 has a disc-like shape centered on the rotation axis 1140 .

[0109] This article also discloses a handheld working tool 1000, which includes a handheld working tool 1000 according to FIG. Fig.13The fan discussed includes a fan housing 1010. The fan 145 is assembled in the fan housing 1010, which includes at least one opening 1310, which is arranged in the fan housing along the periphery and radially outward from the rotation axis 1140 of the fan 145 to receive a first cooling airflow from the axial fan portion 1110 for cooling the first handheld working tool component, and the fan housing also includes a fan vortex 1320, which is centrally arranged in the fan housing to connect with the radial fan portion for guiding a second cooling airflow 160 to cool the second handheld working tool component.

[0110] Fig.16A Details of an optional connector device 1600 for a water hose are shown, which is preferably mounted near the rear handle 195 where the operator can easily access the connector device to attach and detach the water hose. The connector device 1600 includes a water hose connector component 1610, shown here as a connector for a water hose quick connector system, i.e., a male connector component, which faces rearwardly away from the circular cutting tool 130. The connector connector 1610 is fixedly mounted on the machine housing by a bracket 1620 so that the water hose connector component 1610 is fixedly held relative to the working tool. Alternatively, the female water hose connector component can be fixedly mounted on the working tool by a similar bracket to obtain the same technical effects and advantages. The water hose 1630 extends away from the connector component 1610 toward the cutting tool 130. The water hose 1630 is arranged to be at least partially embedded in the tool housing so as to protect the water hose from damage during use of the tool 100.

[0111] Known water hose connector devices usually include a hose section between a bracket on the work tool and a connector part (male connector part or female connector part), which means that it is difficult to connect and disconnect the water hose with one hand. However, since the connector joint 1610 is fixedly mounted on the machine housing by the bracket 1620, the connector device 1600 allows the water hose for supplying water to the cutting tool 130 to be attached and detached with one hand during operation. Therefore, the connector part is firmly supported by the machine housing, where it is easily accessible and does not move around. For example, the operator can hold the tool by the front handle 190 with one hand and connect the water hose with the other hand. The connector part 1610 can be adapted to be connected to any quick connector system on the market, such as Water hose system.

[0112] The water hose connector assembly 1600 including the connector component 1610 and the bracket 1620 may be implemented on any power tool requiring a water supply and is not limited to the specific tools discussed herein.

[0113] Fig. 16Band Fig. 16C A view of connector arrangement 1600 is shown in more detail. Fig. 16B is with Fig.16A The corresponding view, Fig. 16C The connector device 1600 is shown from an opposite viewpoint. The connector part 1610 and the bracket 1620 are preferably integrally formed, i.e. machined or molded, from one piece of material (e.g., one piece of plastic or metal). An internal joint 1640 for attaching a water hose 1630 can be arranged opposite the connector part 1610 to facilitate assembly of the connector device on a handheld working tool.

[0114] Fig.17A and Fig. 17B Detail of an example battery compartment 150 is shown. An electrical energy source, such as a battery, can be inserted into the battery compartment in an insertion direction 701, i.e., also as shown in FIG. Fig. 9 Inserted into compartment 150 as shown. Fig.17A is a view opposite to the insertion direction 701, and Fig. 17B is a view looking into the compartment 150 in the insertion direction 701. Fig. 9 The locking member 710 discussed may be Fig.17A and Fig. 17B The following will be combined with 18A to 18C The battery discussed in greater detail optionally includes a rear surface formed as a handle to simplify insertion and removal of the battery into the battery compartment 150 .

[0115] Batteries used to power heavy cutting tools, such as the work tools discussed herein, are generally quite heavy. Therefore, the batteries must be held in the battery compartment 150 in a robust and reliable manner. To this end, the battery compartment 150 includes a battery holding mechanism that is particularly suitable for supporting heavy batteries, i.e., weighing in the order of 5 kg, for example between 3 kg and 7 kg.

[0116] As described above, the battery compartment 150 extends transversely through the housing of the tool 100, 200, where it defines a volume for receiving the battery. The volume is bounded by a rear wall Rw and a front wall Fw, wherein the rear wall Rw is located toward the rear handle 195 on the tool 100 and the front wall Fw is located toward the front of the tool 100, i.e., toward the cutting tool 130. The bottom surface Bs and the top surface Fs also define the volume. Fig.17A and Fig. 17B The instance volume in is a rectangular shape with rounded corners.

[0117] The battery holding mechanism includes a support heel 1710 arranged on the middle section of the side wall of the battery compartment, more specifically, on the rear wall Rw closest to the rear handle 195. The heel 1710 is elongated, and its elongation direction extends transversely through the battery compartment, aligned with the insertion direction of the battery in the battery compartment 150. When the machine is resting on the ground support member 280, the support heel 1710 is parallel to the ground. Moreover, when the tool 100 is maintained in the normal operating position, the support heel is parallel to the ground and thus supports the battery against gravity. It should be understood that the support heel 1710 can also be arranged on the front wall, that is, on any one of the front wall and / or rear wall of the battery compartment. 18A to 18C The battery illustrated in and discussed below includes a corresponding groove that cooperates with the support heel.

[0118] According to some aspects, support heel 1710 is metal sheathed (shod) to increase mechanical integrity, that is, support heel 1710 is optionally constructed with an outer metal layer for increased mechanical strength.

[0119] According to some other aspects, the battery compartment further comprises an upper groove 1720 and a lower groove 1730 for supporting the battery in the battery compartment 150. The grooves are arranged to cooperate with corresponding ridge structures on the battery so that the battery can be inserted into the battery compartment 150 along the insertion direction 701 at a position that cooperates with the grooves. Thus, the support heel 1710 and the grooves 1720, 1730 together support the battery in the battery compartment in a safe and strong manner. The grooves 1720, 1730 have the function of guiding the battery when it is inserted into the battery compartment 150 and preventing snagging when the battery is removed from the battery compartment 150.

[0120] The grooves 1720, 1730 are preferably formed as dovetail grooves.

[0121] According to some aspects, grooves 1720, 1730 are metal-clad for increased mechanical strength, ie, the grooves are reinforced with a lining layer of metal for increased mechanical strength.

[0122] Fig. 17B It is also shown that the above combination Figure 7C The two elastic members 780 discussed are arranged to push the battery into a locked position, ie to push the electrical energy source in a direction opposite to the insertion direction 701 .

[0123] A contact strip 1740 extending in the insertion direction 701 is arranged in the battery compartment 150 to mate with a corresponding electrical connector arranged in a slot on the battery.

[0124] This article also discloses 18A to 18CThe battery 1800 shown is for insertion into the battery compartment 150. The battery 1800 has a weight between 3-7 kg and includes a groove 1810 arranged on one side of the battery to cooperate with a corresponding support heel 1710 arranged on the wall of the battery compartment 150. The groove optionally has an initial slope to simplify the cooperation with the support heel 1710. The battery 1800 also includes an upper ridge structure 1820 and a lower ridge structure 1830 on the opposite side of the battery compared to the groove 1810, as shown in Figure 18, for cooperation with the corresponding grooves 1720, 1730 of the battery compartment 150. Therefore, the battery 1800 is configured to be inserted into the combination Fig.17A and Fig. 17B In the battery compartment 150 discussed.

[0125] The grooves 1720, 1730 are preferably formed as dovetail grooves.

[0126] The battery 1800 includes at least one recess 760 configured to receive a corresponding locking member 710 of the battery locking mechanism 700 as described above. The locking member includes a front edge portion 750 having an arcuate shape, and the recess 760 includes a surface 770 arranged to engage the front edge portion 750. The surface 770 has an arcuate shape that matches the arcuate shape of the front edge portion 750. Fig.18A As shown, two recesses are advantageously arranged on either side of the elongated support heel 1710 .

[0127] 18A to 18C The battery 1800 illustrated in FIG. 1 also includes one or more electrical connectors 1840 , which are protectively arranged in slots extending in the insertion direction to cooperate with corresponding contact strips 1740 arranged in the battery compartment 150 .

[0128] Optionally, the battery 1800 includes a front surface F1 facing the insertion direction 701 when the battery 1800 is inserted into the battery compartment 150 and a rear surface F2 opposite to the front surface, wherein the rear surface is formed as a handle 1850 to allow grasping by one hand.

[0129] The battery further comprises an electrical connector 1840 which is arranged in a slot extending in the insertion direction to cooperate with a corresponding contact strip 1740 arranged in the battery compartment 150. The electrical connector is thereby protected from mechanical shocks.

[0130] To facilitate battery cooling, Fig.18C As shown, an air inlet is arranged on the bottom side of the battery, which is in fluid communication with an air outlet 1860 arranged on the upper side of the battery. Thus, airflow 160 from fan 145 can be directed through battery 1800 to better cool the battery cells.

[0131] The batteries and battery compartments discussed in conjunction with Figures 17 and 18 may also be used with other hand tools. Thus, the features disclosed in conjunction with the battery compartment and batteries are not dependent on any other specific features of the tools discussed herein.

[0132] Fig.19 An example handheld electric cutting tool 1900 is shown, which includes a first portion 110 and a second portion 120, which are arranged to be vibrationally isolated from each other by one or more damping members 170, 1910, which are optionally combined with one or more resilient members (e.g. Figure 2A and Figure 2C As shown in the metal spring 210) combination. Fig.25 Discussed in more detail, the first portion is associated with a first mass M1 and the second portion is associated with a second mass M2. Notably, the ratio of the second mass M2 to the sum of the masses M1+M2 is much greater than conventional values ​​for, for example, similarly sized internal combustion engine powered cutting tools. This mass ratio provides a more effective anti-vibration function between the first portion and the second portion, as well as a more stable cutting operation, and also improves operator comfort during operation.

[0133] A problem that may potentially occur in handheld cut-off tools of the type discussed herein is that the cutting disk 130 becomes slightly oval during use. This is an undesirable situation because an overly oval cutting disk impedes cutting performance and may cause discomfort to the operator. An oval cutting disk may also be associated with an undesirably increased risk of kickback. An example of an oval cutting disk 130 is Fig.19 The oval cut disk is associated with a variation in the disk "diameter" D1, D2 measured on the disk, i.e., Fig.19 The D1 and D2 in are not equal and differ by a non-negligible amount. The measurements D1 and D2 can be viewed as half of the semi-minor and semi-major axes of the ellipse, although it will be appreciated that an elliptical cutting disk is typically not a perfect ellipse but rather exhibits non-uniformity of radius along its perimeter.

[0134] This problem with oval cutting disks tends to be more pronounced for lower cutting disk angular velocities ω, such as when the cut-off tool is operated at rotational speeds below about 3600-4000 rpm, where the rotational speed is measured at the rotational axis of the cutting disk 130. Hand-held electric cut-off tools that include vibration-isolated first and second portions, such as the tools 100, 200, 800, 1000, 1900 discussed herein, may be particularly susceptible to problems with oval cutting disks.

[0135] According to some aspects, the invention discussed herein and particularly in conjunction with Figures 19 to 22The hand-held electric cutting tool in question is arranged to operate at a cutting disc rotation speed ω of less than 4000 rpm and preferably of about 3200 rpm.

[0136] A solution to the oval disk problem may be to simply increase the cutting disk rotation speed ω, for example, to a speed in excess of 4000 rpm. However, such high cutting disk speeds are undesirable for a number of reasons.

[0137] For example, when dry cutting, i.e., when cutting concrete or stone by a handheld electric cut-off tool without adding a fluid such as water to the cutting area, if the cutting disc speed is too high, it becomes difficult to effectively collect the generated dust, so it is desirable to reduce the cutting disc speed in dry cutting applications. Suitable cutting disc speeds for dry cutting applications are typically on the order of about 3100-3300 rpm, preferably about 3200 rpm. These speeds can even be considered as maximum cutting speeds under normal dry cutting operating conditions.

[0138] High cutting disc speed also means that the cutting disc stores more energy during operation. This in turn means that, for example, during a kickback event, it becomes more difficult to quickly reduce the cutting disc speed by braking. Therefore, for safety reasons, it may be desirable to limit the cutting disc speed to a speed of about 3100-3300 rpm, for example, to about 3200 rpm.

[0139] Furthermore, if the cutting disc speed is too high, the electric cut-off tool may face challenges in generating sufficient torque for an effective cutting operation. For this reason, a cutting disc speed ω of the order of about 3100-3300 rpm may be preferred.

[0140] It will be appreciated that the above cutting disc speeds are merely examples and depend on many aspects such as type of tool, cutting disc size, motor specification etc. However, the general principle of high versus low cutting disc speeds applies to most cut-off tools.

[0141] It has been recognized that if a damping member is arranged between the first part 110 and the second part 120, optionally combined with an elastic member formed as a metal spring so as to effectively isolate vibration, the problem of the oval cutting disk can be alleviated. These damping members are different from conventional spring-based anti-vibration elements commonly used on this type of tool because they are formed by elastic materials associated with a damping coefficient. The damping member suppresses the oscillating behavior between the two masses of the handheld electric cutting tool, which includes a first part and a second part arranged to be vibration-isolated from each other. Through this suppression, the tendency to form an oval cutting blade at a low cutting disk speed is alleviated. This is at least in part because, in the absence of a damping member, the two masses of the de-vibrating cutting tool operating at a given cutting disk speed can enter this oscillating behavior to apply different cutting pressures on different parts of the cutting blade. That is, the oscillating motion can become synchronized with the rotation of the cutting disk. When the system including the first part 110 and the second part 120 enters this type of oscillating state, an oval cutting disk can be generated.

[0142] Modern internal combustion powered cutting tools usually include elastic elements in the form of metal springs to dampen vibrations between the motor and cutting disc components and the components with the handle. However, these springs are not damping members in the sense of damping the oscillatory behavior of one mass relative to another. The relative harmonic motion between the two masses can be approximated by the behavior of two masses connected by a spring, where the restoring force follows Hooke's law and is proportional to the displacement of the two masses from the equilibrium position. Any system that obeys simple harmonic motion is called a simple harmonic oscillator. This type of oscillatory behavior can be mitigated by adding a damping effect to the system, which can be done by adding a damping member associated with a damping coefficient (usually denoted as c) or a device that limits the stroke length of one component relative to another. The damping ratio is a measure that describes how quickly the oscillation decays from one "bounce" to the next. The damping ratio can vary from undamped (ξ=0), underdamped (ξ<1) through critical damping (ξ=1) to overdamped (ξ>1). Adding a damping member to the mass-spring system has an effect on the damping ratio.

[0143] Also refer to Figure 1 , Fig.19 A hand-held electric cutting tool 1900 is shown, which includes a first portion 110 and a second portion 120 arranged to be vibration-isolated from each other. The first portion 110 includes a cutting disc 130 (arranged to support the Fig.19 The second part 120 includes a front handle 190 and a rear handle 195 for operating the cutting tool, and a battery compartment 150 for holding an electrical storage device 220, 1800 such as a battery, which is arranged to power the motor 140. 18A to 18C An example of such a battery is discussed.

[0144] Notably, one or more damping members 170, 1910 are disposed between the first portion 110 and the second portion 120, wherein at least one damping member 170, 1910 is formed of an elastic material associated with a damping coefficient.

[0145] The one or more damping members are arranged to dampen or disrupt oscillations of the second part 120 relative to the first part 110. Thus, the risk of ending up with an oval cutting disc is mitigated.

[0146] According to various aspects, the at least one damping member 170, 1910 is made of rubber, an elastic plastic material, a closed-cell foam, or an elastic synthetic resin. What these damping members have in common is that they introduce a damping coefficient into the resonance equation of the mechanical system including the first part 110 and the second part 120. This damping coefficient effectively damps the oscillatory behavior of the first part relative to the second part. For example, a collar of closed-cell foam may surround Figure 1 The flexible airflow duct 170 arrangement is shown, or a collar of closed cell foam may even constitute the flexible airflow duct 170 .

[0147] Preferably, since metal springs are more effective in vibrationally isolating components from each other, the first portion 110 is vibrationally isolated from the second portion 120 by one or more elastic elements 210 in addition to the at least one damping member 170, 1910, wherein the one or more elastic elements 210 include at least one metal spring. Thus, the combination of the metal spring and the elastic material damping member together provide effective vibration isolation and a reduced risk of producing an oval cutting disc during operation of the cut-off tool.

[0148] Fig.19 Two example types of damping members are shown that can be used independently of each other or in combination. It should also be understood that the present teachings cover other types of damping members applied at other locations between the first portion and the second portion. For example, between can also be interpreted to cover such a damping member that is attached to both the first portion and the second portion, but extends outside of the narrow slot 1930 formed between the first portion and the second portion.

[0149] Fig. 20 Two example damping members 1910, 1920 are shown. The first damping member 170 is connected to the bellows 2100 (in Fig.2110) or other flexible airflow conduit disposed between the first portion 110 and the second portion 120. This bellows or flexible airflow conduit provides a damping coefficient as described above to provide a desired damping ratio and also serves to limit the stroke length associated with the relative motion of the first portion 110 relative to the second portion 120. When the first portion 110 is in Fig.21 When moving towards the second part 120 in the direction C shown, the reinforcing elements 1920 arranged on at least one side of the bellows, for example on both sides or more of the bellows 2100, limit the compression of the bellows, thereby limiting the stroke length of the oscillating movement, thereby interfering with the oscillating behavior.

[0150] The compressibility of the bellows in relation to the Shore hardness can be adjusted by selecting the type of material used for the reinforcing element 1920 or by determining the thickness dimensions of the material used in the element and the bellows in order to obtain a desired damping ratio of the damped mass-spring system comprising the first portion and the second portion. Fig.21 As shown, the compressibility can also be adjusted by arranging one or more cavities 1930 in the reinforcing element 1920. According to various aspects, the bellows 2100 is arranged between the first portion 110 and the second portion 120, wherein the bellows 2100 is associated with a Shore durometer value or Shore hardness between 50-100, preferably between 65-90, measured with a durometer type A according to DIN ISO 7619-1. Therefore, it should be understood that the compressibility can be adjusted, for example Figure 4 and / or Fig.21 The Shore hardness and material thickness of the bellows are shown to mitigate the occurrence of oval cutting disks in hand-held electric cut-off tools by either introducing a damping coefficient in the mass-spring system to suppress oscillations; or introducing a stroke length limitation to disrupt oscillations; or both.

[0151] According to another example, Fig. 20 As shown, at least one damping member 1910 is fixedly attached to one of the first portion 110 or the second portion 120 and is arranged to be spaced a certain distance from the other of the first portion 110 or the second portion 120. Therefore, the at least one damping member 1910 is arranged to limit the stroke length associated with the relative movement of the first portion 110 relative to the second portion 120. This damping member has a combination with the above Fig.21 The function of the stiffening element 1920 discussed above is similar in function. It is positioned to limit the travel length of the oscillatory motion between the first and second parts and thus interfere with any oscillatory behavior of the first part 110 relative to the second part 120. Fig. 22 A more detailed view of the damping member 1910 is shown in . According to this example, it is integrally formed from a single piece of resilient material and mounted on the body of the first part 110 or the second part 120 .

[0152] Alternatively, a damping member 1910 or some other resilient element may be attached to both the first portion 110 and the second portion 120, thereby forming an elastic bridge between these components. Since a damping member is associated with a damping coefficient, the damping ratio of the resulting damped mass-spring system will be affected by the addition of such a damping member, and the tendency of the elliptical cutting disk may be mitigated.

[0153] Since it is now possible to maintain a low cutting disc speed without the risk of producing an elliptical cutting disc, an electrical kickback protection mechanism can be advantageously implemented. This is because a kickback protection mechanism based on braking of the motor 140 may not be effective at very high cutting disc speeds. Therefore, according to some aspects, the motor 140 is arranged to be controlled by a control unit of the cut-off tool via a motor control interface. The control unit is arranged to obtain data indicating the angular velocity of the cutting disc 130 and to detect a kickback condition based on a reduction in the angular velocity. The control unit is also arranged to control the electromagnetic braking of the motor 140 in response to detecting a kickback condition.

[0154] In order to provide a kickback mitigation function that is also suitable for high-power cutting tools associated with significant tool inertia (which responds quickly enough and has sufficient braking force), a handheld electric cutting tool for cutting concrete and stone with a rotatable cutting disc 130 is disclosed herein. The cutting tool includes a motor 140, which is arranged to be controlled by a control unit via a motor control interface. The control unit is arranged to obtain data indicative of the angular velocity of the cutting disc 130, and to detect a kickback condition based on a decrease in the angular velocity. The control unit is also arranged to control electromagnetic braking of the motor 140 in response to detecting the kickback condition, and optionally is also arranged to actively adjust the energy output from the motor through the control interface during electromagnetic braking.

[0155] The detection mechanism is based on monitoring the angular velocity of the cutting disc 130. If a sudden decrease in speed is seen, such as a high level of delay in the electric rotor angle or the cutting disc angle, a kickback condition is detected. After the control unit detects a kickback event, the motor is forced to brake immediately in order to mitigate the effects of the kickback event. This braking includes actively controlling the energy output from the motor in order to provide forced power without damaging the electrical components of the cutting tool. This braking is facilitated by the fact that the cutting disc is operated at a speed lower than 3500 rpm, for example at 3200 rpm, which is made possible by the presence of the damping member.

[0156] The kickback detection and braking of the cutting disc is typically so rapid that the blade is stopped before it even leaves the object being processed. Even if some kickback motion occurs, the energy transferred from the cutting disc 130 to the body of the machine will be reduced to a level so as to mitigate the harmful effects of the kickback event. It is noteworthy that the motor is not simply disconnected from the power supply as in many prior art documents. Instead, the energy output from the motor is actively adjusted to provide a sufficiently strong braking action to stop the kickback event.

[0157] Also refer to Figure 1 , Fig.23 Details of a hand-held electric cutting tool 2300 are shown, the hand-held electric cutting tool comprising a fan 145 arranged to be driven by the motor 140 to generate a cooling airflow 160, and a battery compartment 150 comprising an electrical storage device 220, 1800, such as a battery, arranged to power the motor 140. The cooling air duct is arranged to direct the cooling airflow 160 towards an outlet hole 1750 formed in a wall of the battery compartment 150 (e.g., at Fig. 17B The outlet opening 1750 faces a corresponding inlet opening 1870 formed in the housing of the electrical storage device 220, 1800 for receiving cooling air, thereby generating an air pressure higher than atmospheric pressure in the electrical storage device 220, 1800. Fig.24 The first slot segment Ss1 is formed by the distance between the outlet hole 1750 and the inlet hole 1870 on the electrical storage device 220, so that the first portion 2415 of the cooling airflow 160 leaks to the outside of the cutting tool through the first slot segment Ss1.

[0158] This first portion 2415 of the cooling airflow 160 creates an air pressure within the first slot segment that must be overcome by dust and mud that enters the slot between the electrical storage device 220 and the compartment wall. Thus, dust and mud are prevented from entering the slot, and the battery compartment is kept clean, which is an advantage. A clean battery compartment free of accumulated dust and mud simplifies the insertion and removal of the electrical storage device 220 from the tool.

[0159] The first portion 2415 of the cooling airflow is directed transversely to the overall cooling airflow 160 entering the electrical storage device 220, 1800. Furthermore, this first portion may leak on both sides of the cutting tool, ie from both sides of the battery compartment through-hole.

[0160] According to one example, the first slot segment Ss1 is defined on one side by a guide device that guides the electrical storage device 220 into the compartment. The first slot segment Ss1 may also be defined by a support heel 1710. However, it should be noted that the slot segments Ss1, Ss2, and Ss3 may be connected to each other or defined by other defining devices.

[0161] According to various aspects, the distance between the electrical storage device 220 , 1800 and the wall of the battery compartment 150 is between 0.5 mm and 2.0 mm, preferably about 1.0 mm. This distance can vary around the electrical storage device 220 .

[0162] The electrical storage device 220, 1800 may also include one or more electrical connectors 1840 arranged to mate with corresponding contact strips 1740 arranged in the battery compartment 150. An example of these electrical connectors is shown in FIG. Fig.18C 1840. An opening connected to the electrical connector 1840 is formed in the housing of the electrical storage device 220, 1800 so that a second portion 2425 of the cooling air flow passes through the opening and leaks out to the outside of the cutting tool via a second slot segment Ss2 formed between the electrical storage device 220, 1800 and the wall of the battery compartment 150. Therefore, since the battery housing is not hermetically sealed around the electrical connector 1840, the overpressure of the cooling air inside the electrical storage device 220 generates an air flow that leaves via the electrical connector and passes via the second slot segment. Likewise, this air flow leaving the machine via the slot must be overcome by dust and mud if the slot is to be entered. This is not possible because the leakage is a considerable flow relative to the more diffuse movement of dust and mud generated by the cutting operation. The electrical connector is therefore kept clean and free of mud during operation, which is an advantage, in particular because insertion and removal of the electrical storage device 220 becomes easier if the connector and the guide device are clean. The second slot segment Ss2 may, for example, be made of Fig.18C An upper ridge structure 1820 and a lower ridge structure 1830 are shown defining.

[0163] Finally, an air outlet 1860 may also be formed in the electrical storage device housing opposite the inlet hole 1870 to form a passage for cooling air to flow through the electrical storage device. A third slot segment Ss3 may be formed by the distance between the air outlet 1860 and the wall of the battery compartment 150 so that a third portion 2435 of the cooling airflow 160 leaks to the exterior of the cutting tool via the third slot segment Ss3. This third slot segment also provides a passage for cooling air to leak through the slot, thereby keeping the space between the top of the electrical energy device 220 and the battery compartment wall clean and free of dust and mud.

[0164] Fig.25 Schematically shows the above combination Figures 1 to 24 It has been found that the weight distribution between the components of a handheld electric cut-off tool comprising a first portion and a second portion arranged in vibration isolation from each other can be optimized to obtain a more efficient cutting operation while reducing operator discomfort caused by vibrations transmitted from the machine via the handle to the operator.

[0165] De-vibrating gasoline fuel cut-off tools are known, i.e., internal combustion engine powered tools. However, these known tools have a suboptimal weight distribution between the handle part and the parts including the internal combustion engine and the cutting disc. Some known gasoline powered cut-off machines have a handle portion that weighs about 2600 g with an empty fuel tank and 3500 g with a full fuel tank compared to the electric motor, and have an arm portion that weighs about 7550 g, i.e., the empty tank ratio is 2600 g / 10150 g (which is equal to about 0.25), and 3500 g / 11050 g (which is about 0.32) with a full tank. The ratio of the full tank can be compared with the case where the battery (mass M3) is assembled in the mass M2 (i.e., M2+M3), while the empty tank case can be compared with the case without the battery (i.e., only M2).

[0166] If the part has a handle, that is Fig.25 It is advantageous that the masses M2 and M3 in the embodiment have sufficient weight to withstand the vibrations propagated through the damping element and the elastic element. However, the part with the cutting blade, i.e. the masses M1 and M4, cannot be too light relative to the handle part, as this would result in an unbalanced tool.

[0167] It has been found through extensive experiments and computer analysis that the ratio of the second mass M2 to the sum of the first and second masses M1+M2 should preferably be at least 0.3, preferably greater than 0.35, i.e. the second mass should constitute a substantial portion of the total mass of the cut-off tool without the cutting disc and the electrical storage device mounted. For example, the ratio M2 / (M1+M2) may be about 0.38 for a 12-inch blade arrangement and about 0.37 for a 14-inch blade arrangement. However, the second mass M2 should not be too large relative to the first mass. Therefore, the ratio of the second mass M2 to the sum of the first and second masses M1+M2 should preferably be lower than about 0.5, preferably lower than about 0.6.

[0168] It has also been found that the ratio of the sum of the second and third masses (i.e., M2+M3) to the sum of the first and fourth masses (M1+M4) should be at least 0.6, preferably greater than 0.8, and even more preferably greater than 1.0. These ratios provide a well-balanced tool with excellent vibration resistance.

[0169] It has also been found that the ratio of the sum of the second and third masses (M2+M3) to the sum of the weight of the entire device including the electrical energy storage device and the cutting disc (i.e. M1+M2+M3+M4) should be at least 0.45, preferably greater than 0.5. This ratio provides a stable tool with good anti-vibration properties.

[0170] In summary, disclosed herein is a handheld electric cutting tool 100 , 200 , 800 , 1000 , 1900 , 2500 that includes a first portion 110 and a second portion 120 that are arranged to be vibrationally isolated from each other.

[0171] The first part 110 comprises an interface 2510 for holding a cutting tool 130 and a motor 140 arranged to drive the cutting tool, wherein the first part is associated with a first mass M1 .

[0172] The second portion 120 comprises a battery compartment 150 for holding an electrical storage device 220 arranged to power the electric motor 140 and a front handle 190 and a rear handle 195 for operating the cutting tool, wherein the second portion is associated with a second mass M2.

[0173] The ratio of the second mass M2 to the sum of the first mass and the second mass M1+M2 is at least 0.3, preferably greater than 0.35.

[0174] Also disclosed herein is a handheld electric cutting tool 100 , 200 , 800 , 1000 , 1900 , 2500 , which includes a first portion 110 and a second portion 120 arranged to be vibration-isolated from each other, a cutting tool 130 , and an electric storage device 220 .

[0175] The first part 110 comprises an interface 2510 for holding a cutting tool 130 and a motor 140 arranged to drive the cutting tool, wherein the first part is associated with the first mass M1 and wherein the cutting tool is associated with the fourth mass M4.

[0176] The second part 120 comprises a battery compartment 150 for holding an electrical storage device 220 arranged to power the motor 140 and a front handle 190 and a rear handle 195 for operating the cutting tool, wherein the second part is associated with the second mass M2, and wherein the electrical storage device 220 is associated with the third mass M3.

[0177] Therein, the ratio of the sum of the second mass and the third mass M2+M3 to the sum of the first mass and the fourth mass M1+M4 is at least 0.6, preferably greater than 0.8, and even more preferably greater than 1.0.

[0178] Furthermore, disclosed herein is a handheld electric cutting tool 100 , 200 , 800 , 1000 , 1900 , 2500 , which includes a first portion 110 and a second portion 120 arranged in vibration isolation from each other, a cutting tool 130 , and an electric storage device 220 .

[0179] The first part 110 comprises an interface 2510 for holding a cutting tool 130 and a motor 140 arranged to drive the cutting tool, wherein the first part is associated with the first mass M1 and wherein the cutting tool is associated with the fourth mass M4.

[0180] The second part 120 comprises a battery compartment 150 for holding an electrical storage device 220 arranged to power the motor 140 and a front handle 190 and a rear handle 195 for operating the cutting tool, wherein the second part is associated with the second mass M2, and wherein the electrical storage device 220 is associated with the third mass M3.

[0181] Therein, the ratio of the sum of the second mass and the third mass (M2+M3) to the sum of the weight of the entire device including the energy storage device and the cutting disk (M1+M2+M3+M4) is at least 0.45, preferably greater than 0.5.

[0182] The following table provides example weight distributions that may be advantageously used with the handheld electric cutting tools discussed herein. The table has included examples of two different sized batteries, a large battery weighing approximately 5100 g (denoted as M32) and a smaller battery weighing approximately 3000 g (denoted as M31).

[0183] <![CDATA[ Part Weight Example ]]> <![CDATA[ 12-inch blade ]]> <![CDATA[ 14-inch blade ]]> M1 4500g 4720g M2 2750g 2750g M31-Small battery 3000g 3000g M32-Large battery 5100g 5100g M4 1250g 1850g relation M2 / (M2+M1) ～0.38 ～0.37 (M2+M31) / (M1+M4) ～1.0 ～0.88 (M2+M32) / (M1+M4) ～1.37 ～1.19 (M2+M31) / (M1+M2+M31+M4) 0.5 ～0.47 (M2+M32) / (M1+M2+M32+M4) ～0.58 ～0.54

Claims

1. A hand-held electric cutting tool (100, 200, 800, 1000, 1900), comprising a first part (110) and a second part (120) arranged to be vibration-isolated from each other, The first part (110) comprises an arm (116) arranged to support a cutting disc (130) and a motor (140) arranged to drive the cutting disc, The second portion (120) comprises a front handle (190) and a rear handle (195) for operating the handheld electric cutting tool and a battery compartment (150) for holding an electrical storage device (220, 1800) arranged to supply power to the electric motor (140), in, One or more damping members (170, 1910) are arranged between the first portion (110) and the second portion (120), wherein at least one damping member (170, 1910) is formed of an elastic material associated with a damping coefficient, the damping coefficient being introduced into a resonance equation of the handheld electric cutting tool including the first portion (110) and the second portion (120) to effectively dampen an oscillatory behavior of the first portion relative to the second portion; and Wherein, in addition to the at least one damping member (170, 1910), the first part (110) is vibrationally isolated from the second part (120) by one or more elastic elements (210), wherein the one or more elastic elements (210) include at least one metal spring.

2. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1, wherein: The at least one damping member (170, 1910) is arranged to dampen or interfere with oscillations of the second part (120) relative to the first part (110).

3. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, wherein: The at least one damping member (170, 1910) is made of rubber, elastic plastic material, closed-cell foam or elastic synthetic resin.

4. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, wherein: The at least one damping member (170) is formed as a reinforcing element (1920) integrated with a flexible airflow duct arranged between the first portion (110) and the second portion (120).

5. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, wherein: A bellows (2100) is arranged between the first portion (110) and the second portion (120), wherein the bellows (2100) is associated with a Shore durometer value or Shore hardness between 50 and 100 measured with a durometer type A according to DIN ISO 7619-1.

6. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 5, wherein: The bellows (2100) is associated with a Shore durometer value or Shore hardness between 65 and 90 measured with a type A durometer according to DIN ISO 7619-1.

7. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, wherein: The at least one damping member (1910) is fixedly attached to one of the first portion (110) and the second portion (120) and arranged to be spaced apart from the other of the first portion (110) and the second portion (120), wherein the at least one damping member (1910) is arranged to limit a stroke length associated with relative movement of the first portion (110) relative to the second portion (120).

8. The hand-held electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, arranged to operate at a cutting disc rotation speed of less than 3600 rpm.

9. The hand-held electric cutting tool (100, 200, 800, 1000, 1900) according to claim 8, arranged to operate with a cutting disc rotation speed of 3200 rpm.

10. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, wherein: The motor (140) is arranged to be controlled by a control unit of the handheld electric cutting tool via a motor control interface, wherein the control unit is arranged to obtain data indicative of an angular velocity of the cutting disc (130) and detect a kickback condition based on a reduction in the angular velocity, and wherein the control unit is arranged to control electromagnetic braking of the motor (140) in response to detecting a kickback condition.

11. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, in, The first portion is associated with a first mass (M1), wherein the second portion is associated with a second mass (M2), and wherein a ratio of the first mass (M1) to a sum of the first mass and the second mass (M1+M2) is at least 0.

3.

12. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 11, wherein a ratio of the first mass (M1) to the sum of the first mass and the second mass (M1+M2) is greater than 0.

35.

13. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, in, The first portion is associated with a first mass (M1), and wherein the cutting disk is associated with a fourth mass (M4), wherein the second portion is associated with a second mass (M2), and wherein the electrical storage device (220) is associated with a third mass (M3), Wherein, a ratio of a sum of the second mass and the third mass (M2+M3) to a sum of the first mass and the fourth mass (M1+M4) is at least 0.

6.

14. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 13, wherein: A ratio of a sum of the second mass and the third mass (M2+M3) to a sum of the first mass and the fourth mass (M1+M4) is greater than 0.

8.

15. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 13, wherein: A ratio of a sum of the second mass and the third mass (M2+M3) to a sum of the first mass and the fourth mass (M1+M4) is greater than 1.

0.

16. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, in, The first portion is associated with a first mass (M1), and wherein the cutting disk is associated with a fourth mass (M4), wherein the second portion is associated with a second mass (M2), and wherein the electrical storage device (220) is associated with a third mass (M3), Wherein a ratio of a sum of the second mass and the third mass (M2+M3) to a sum of the weights of the entire device including the electrical storage device and the cutting disk is at least 0.

45.

17. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 16, wherein: The ratio of the sum of the second mass and the third mass (M2+M3) to the sum of the weights of the entire device including the electrical storage device and the cutting disk is greater than 0.

5.

18. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, in, The cooling air duct is arranged to direct a portion of the cooling air flow (160) from the first portion (110) and into the second portion (120) to cool the electrical storage device.

19. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, wherein: A portion of the cooling air flow (160) entering from the first portion (110) into the second portion (120) is arranged to pass through a control unit of the handheld electric cutting tool (100).

20. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1 or 2, wherein: A portion of the cooling airflow (160) directed from the first portion (110) to the second portion (120) passes through a flexible airflow duct arranged between the first portion (110) and the second portion (120).

21. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 1, wherein: The electrical storage device is a battery.

22. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 4, wherein: The at least one damping member (170) is formed as a reinforcing element (1920) integrated with a bellows (2100) arranged between the first portion (110) and the second portion (120).

23. The handheld electric cutting tool (100, 200, 800, 1000, 1900) according to claim 20, wherein: A portion of the cooling air flow (160) directed from the first portion (110) to the second portion (120) passes through a bellows arranged between the first portion (110) and the second portion (120).

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