Battery for insertion into handheld power tools and handheld power tools equipped with a battery

Abstract

This tool provides a battery that is securely held in place by the tool, and allows the battery to be easily released from the tool. [Solution] A battery (1800) to be inserted into a battery compartment (150) of a handheld work tool (100, 200), wherein the battery (1800) weighs 3 kg to 7 kg and has a groove (1810) located on one side of the battery to fit into a corresponding support heel (1710) located on the wall of the battery compartment (150). The battery further comprises an upper ridge structure (1820) and a lower ridge structure (1830) located on the opposite side of the battery compared to the groove (1810), the ridge structures (1820, 1830) configured to fit into corresponding grooves (1720, 1730) of the battery compartment (150).

Description

Technical Field

[0001] The present disclosure relates to an electric hand-held working device such as a cutting tool and a saw for cutting concrete and stone.

Background Art

[0002] A hand-held working tool for cutting and / or polishing hard materials such as concrete and stone includes a powerful motor to provide the power required to process the hard materials.

[0003] For working tools used at construction sites, ease of operation is particularly important. In the case of electric working tools, it is desirable that the battery can be easily inserted into the working tool, the battery is firmly held in the working tool, and the battery can be easily released from the working tool, and on-site battery replacement can be carried out in an efficient and convenient manner.

[0004] In summary, there are problems related to hand-held working tools and their accessories.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present disclosure is to provide a hand-held working tool and an improved battery for the hand-held working tool that address the above problems.

Means for Solving the Problems

[0006] This object is achieved by a battery for insertion into a battery storage part of a hand-held working tool, the battery having a weight of 3 kg to 7 kg and comprising a groove arranged on one side of the battery. The groove is adapted to fit with a corresponding support heel arranged on the wall of the battery storage part. The battery further comprises an upper raised structure and a lower raised structure arranged on the opposite side of the battery compared to the groove. The raised structures are arranged to fit with corresponding grooves in the battery storage part.

[0007] In this way, the battery can be supported within the battery compartment in a safe and robust manner. The raised structure guides the battery when inserting it into the battery compartment and prevents it from getting caught when removing it from the battery compartment.

[0008] According to some embodiments, the raised structure is configured to engage with a corresponding dovetail groove in the battery compartment.

[0009] This shape ensures that the battery is securely guided when it is inserted into the battery compartment.

[0010] According to some embodiments, the battery comprises at least one recess configured to receive each locking member of a battery locking mechanism, the locking member comprising an arc-shaped leading edge. The recess comprises a surface positioned to engage with the leading edge, the surface having an arc shape consistent with the shape of the leading edge. According to some embodiments, two recesses are located on either side of an elongated support heel.

[0011] Having at least one recess allows the battery to be received in the battery compartment, and the locking member that simply yields when the battery is inserted may become inactive.

[0012] In some embodiments, the battery includes one or more electrical connectors protected and positioned in slots extending in the insertion direction, which mate with corresponding contact strips located in the battery housing.

[0013] In this way, the electrical connector is protected from mechanical shock.

[0014] In some embodiments, the battery comprises a front surface that faces the insertion direction when the battery is inserted into the battery compartment, and a back surface opposite to the front surface. The back surface is formed as a handle that can be held with one hand.

[0015] In this way, the battery can be easily handled when inserting it into the battery compartment or removing it from the battery compartment.

[0016] This objective can also be achieved with handheld work tools, which offer the advantages mentioned above.

[0017] Furthermore, according to several embodiments, the battery compartment of a handheld work tool includes a battery locking mechanism, which includes at least one locking member having a leading edge portion rotatably supported on a shaft and configured to fit into a recess formed in the battery, thereby locking the battery in place. The leading edge portion has an arc shape having a curvature corresponding to the curvature of a circular segment having a radius corresponding to the distance from the leading edge portion to the center of the shaft. The recess formed in the battery includes a surface configured to engage with the leading edge portion, and this surface has an arc shape to match the shape of the leading edge portion.

[0018] Thus, once the battery is received in the battery compartment, the locking member becomes inactive and simply yields to the battery as it enters the compartment. The arc shape of the leading edge allows the locking mechanism to rotate from the locked position with less resistance, even if there is some friction between the leading edge and the surface positioned to engage with it.

[0019] In some embodiments, the battery locking mechanism comprises at least one elastic member configured to push the battery into a locked position, wherein the at least one elastic member and the locking member are located on the opposite side of the battery housing.

[0020] In this way, the battery is pushed out in the opposite direction to the insertion direction. When compressed by the battery, the elastic member pushes the battery and repels it from the battery compartment, increasing the contact pressure between the leading edge and the surface configured to engage with the leading edge. This improves the battery retention effect. Furthermore, when the battery is to be ejected from the battery compartment, the elastic member makes it easy to grasp the battery and pull it out of the battery compartment.

[0021] According to some embodiments, the locking member is spring-biased toward the locked position and is operable by a lever or push-button mechanism.

[0022] In this way, when the battery is inserted into the recess, the locking member snaps into the locked position, and when removing the battery from the battery compartment, the spring biasing force can be overcome by the push-button mechanism.

[0023] According to some embodiments, the battery locking mechanism comprises a plurality of locking members arranged at a certain distance apart.

[0024] In this way, the robustness of the locking mechanism is improved.

[0025] Generally, all terms used in the claims should be interpreted according to their ordinary meanings in the technical field, unless otherwise defined herein. All references to "elements, devices, components, means, steps, etc." should be construed openly as referring to at least one instance of the element, device, component, means, step, etc., unless otherwise specified. The steps of the methods disclosed herein need not be performed in the exact order disclosed, unless explicitly stated. Further features and advantages of the present invention will become apparent from consideration of the appended claims and the following description. Those skilled in the art will understand 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.

[0026] This disclosure will be described in more detail with reference to the accompanying drawings.

Brief Description of the Drawings

[0027] [Figure 1] An example of a working tool is shown. [Figure 2A] A diagram of another exemplary working tool is shown. [Figure 2B] A diagram of another exemplary working tool is shown. [Figure 2C] A diagram of another exemplary working tool is shown. [Figure 3A] A diagram of a working tool support arm is shown. [Figure 3B] A diagram of a working tool support arm is shown. [Figure 4] A bellows for guiding an air flow is shown. [Figure 5] A bellows for guiding an air flow is shown. [Figure 6] A bellows for guiding an air flow is shown. [Figure 7A] A locking mechanism is schematically shown. [Figure 7B] A locking mechanism is schematically shown. [Figure 7C] A locking mechanism is schematically shown. [Figure 8] An example of a work tool with a battery locking mechanism is shown. [Figure 9] The details of the battery lock mechanism are outlined below. [Figure 10A] An example diagram of a work tool is shown. [Figure 10B] An example diagram of a work tool is shown. [Figure 10C] An example diagram of a work tool is shown. [Figure 11] A brief overview of the fans. [Figure 12] Here is an example of a fan for a work tool. [Figure 13] An example of a fan housing is shown. [Figure 14A] Details of the tool support arm are shown. [Figure 14B] Details of the tool support arm are shown. [Figure 14C] Details of the tool support arm are shown. [Figure 15] This shows the drive mechanism for driving a circular cutting tool. [Figure 16A] This shows the rear handle section with a water hose connection. [Figure 16B] Details of the water hose connector are shown. [Figure 16C] Details of the water hose connector are shown. [Figure 17A] Details of the battery compartment are shown. [Figure 17B] Details of the battery compartment are shown. [Figure 18A] This shows the battery to be inserted into the battery compartment. [Figure 18B] This shows the battery to be inserted into the battery compartment. [Figure 18C] This shows the battery to be inserted into the battery compartment. [Figure 19] A schematic diagram of cutting tools is shown. [Figure 20] Details of the cutting tool are shown. [Figure 21] An example of a damping member is shown. [Figure 22] Another exemplary damping member is shown. [Figure 23] This shows the flow of cooling air through the components of a cutting tool. [Figure 24] The flow of cooling air is shown in a schematic manner. [Figure 25] The mass distribution of the work tools is shown in general terms. [Modes for carrying out the invention]

[0028] Next, the present invention will be fully described below with reference to the accompanying drawings illustrating specific aspects of the invention. However, the present invention can be embodied in many different forms and should not be construed as being limited to the embodiments and aspects described herein. Rather, these embodiments are provided as examples so that this disclosure fully conveys the scope of the invention to those skilled in the art. Similar reference numerals refer to similar elements throughout this description.

[0029] 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 can be made within the scope of the appended claims.

[0030] Figure 1 shows a handheld work tool 100. The work tool 100 in Figure 1 includes a rotatable circular cutting tool 130, but the technology disclosed herein can also be applied to other cutting tools such as chainsaws and core drills. An electric motor 140 is arranged to drive the cutting tool. This motor is powered by an electrical energy storage device arranged to be held in a battery compartment 150.

[0031] Electric motors generate a considerable amount of heat during operation. To prevent the motor from overheating, a fan 145 is arranged to be driven by the motor 140. This fan can be mounted, for example, directly on the motor shaft or by some kind of transmission device. The fan generates an airflow that dissipates heat from the electric motor, thereby cooling it.

[0032] The work tool 100 is held by a front handle 190 and a rear handle 195 and is configured to be operated by a trigger 196 in a known manner. Since excessive vibration can be unpleasant for the operator using the work tool 100, it is desirable to minimize vibration of the handles and trigger. Excessive vibration can also shorten the lifespan of tool components such as cable connections and electronics. To reduce these vibrations, the work tool 100 comprises a first part 110 and a second part 120 arranged to be vibrationally separated from each other. The first part 110 has an interface for holding a cutting tool 130 and also comprises an electric motor 140 arranged to drive the cutting tool. Thus, the first part constitutes the main vibration-generating element of the work tool.

[0033] In particular, the second part 120 comprises handles 190, 195 and a trigger 196, and thus forms the interface between the work tool 100 and the operator. The second part 120 also comprises a battery compartment 150 for holding an electrical storage device and control electronics for controlling various operations of the work tool 100.

[0034] Since vibrations generated in the first part 110 are not transmitted to the second part 120, or at least not transmitted in significant amounts, the operator of the device 100 has the advantage of being able to work for longer periods under more comfortable working conditions without being subjected to vibrations.

[0035] Vibration is typically measured in m / s². 2 Measured in units of 2.5 m / s², the vibration of the tool in the front and rear handles is measured. 2It is desirable to limit it to less than [amount]. Tool vibration, guidelines for limiting tool vibration, and measurement of tool vibration are described in "VIBRATIONER - Arbetsmiljoverkets foreskrifter om vibrationer samt allmanna rad om tillampningen av foreskrifterna", Arbetsmiljoverket, AFS 2005:15.

[0036] According to some embodiments, the work tool 100 reduces the vibration of the front and rear handles to 2.5 m / s 2 It comprises a first part 110 and a second part 120 that are arranged to be vibration-isolated from each other by a vibration isolation system configured to limit the vibration to a value less than 100.

[0037] The cooling air conduit is arranged to direct a portion 160 of the cooling airflow from a first portion 110 to a second portion 120 in order to cool the electrical storage device. This means that a fan 145 is used to cool both the electric motor 140 and the electrical energy source, which has the advantage that only a single fan is required.

[0038] Here, a conduit is a passage arranged to guide a flow, such as airflow. Cooling air conduits can be formed as part of an internal space enclosed by the work tool body components, as a hose for other types of conduits, or as a combination of different types of conduits.

[0039] Any control electronics included in the second section 120 may also be configured to be cooled by a portion 160 of the cooling airflow that is directed from the first section 110 to the second section 120. Figure 1 schematically shows a cooling flange 180 associated with such control electronics. This cooling flange 180 is optional. That is, if the control unit constitutes the cooling flange, the control unit can be cooled directly using a portion of the cooling airflow. Thus, optionally, a portion 160 of the cooling airflow from the first section 110 to the second section 120 is arranged to pass through the cooling flange 180 associated with the control unit of the handheld work tool 100.

[0040] Since the first and second parts are positioned at least partially vibrationally isolated from each other, it may be difficult to efficiently guide a portion of the air 160 from the first part to the second part. In some embodiments of the disclosed work tool, this problem is solved by providing a bellows or other type of flexible air conduit between the first and second parts to guide a portion of the air from the fan 145 toward the battery housing 150. These bellows 170 are described in detail below in relation to Figures 4-6. Bellows are sometimes called flexible covers, convolutions, accordions, or machineway covers. Instead of bellows, hoses formed of flexible material can also be used.

[0041] In summary, Figure 1 schematically illustrates a handheld work tool 100 comprising a first part 110 and a second part 120 arranged to be vibrationally isolated from each other. According to some embodiments, the first part 110 is vibrationally isolated from the second part 120 by one or more elastic elements.

[0042] The handheld work tool may be a cutting tool, as shown in Figure 1, but it may also be a chainsaw or other work tool for cutting hard materials. The first part comprises an interface for holding the cutting tool 130 and an electric motor 140 arranged to drive the cutting tool. The drive system may include, for example, a belt drive, or a combination of a belt drive and a geared transmission. The electric motor 140 is configured to drive a fan 145 configured to generate a flow of cooling air for cooling the electric motor 140. The fan may be connected, for example, directly to the electric motor shaft, or indirectly to the motor shaft via some transmission or drive system such as a belt drive or a geared transmission.

[0043] The second section 120 includes a battery housing 150 for holding an electrical storage device arranged to supply power to an electric motor 140, and a cooling air conduit is arranged to direct a portion 160 of the flow of cooling air from the first section 110 to the second section 120 to cool the electrical storage device. The electrical energy source may be a battery or some kind of fuel battery.

[0044] Figures 2A–2C show different diagrams of an exemplary handheld work tool 200, arranged to hold the cutting tool by the cutting tool interface 260. The elastic element separating the first part 110 from the second part 120 is here a compression spring 210. However, as previously mentioned, some kind of resilient material member, such as a rubber bushing, can be used instead of or in combination with the spring. A leaf spring may also be an option for vibrationally isolating the first part 110 from the second part 120.

[0045] Figure 2B shows a holder 270 for an additional blade bushing. Cutting discs may vary in dimensions with respect to the central hole of the blade. Some blade holes may have a diameter of 20 mm, while others may be 25.5 mm. There are also markets where a 30.5 mm central blade hole is common. To accommodate different types of blades with different dimensions for the central blade hole, the handheld work tool 200 is equipped with a holder 270 positioned on the work tool body to hold the blade bushing. This additional blade bushing preferably has different dimensions compared to the blade bushing that is attached and connected to the cutting tool interface 260.

[0046] Figure 2A shows an exemplary electrical storage device 220, in this case a battery, mounted in the battery housing 150. This battery can be held in place by a battery locking mechanism, which will be described in more detail below in relation to Figures 7A-7C, 8, and 9. Other types of electrical energy sources that can be used with the devices and techniques disclosed herein include, for example, fuel batteries and supercapacitors.

[0047] In some embodiments, the cooling airflow for cooling the electric motor 140 extends laterally through the handheld work tool 230, 245, 201 relative to the extension surface of the circular cutting tool 130. Here, referring to Figure 2C, laterally should be interpreted in relation to the extension direction 202 of the work tool extending from the rear handle 195 toward the cutting tool, and the extension surface of the cutting tool 130 (which is more or less perpendicular in Figure 2C). Air from the environment is drawn into the work tool through an air intake 230 on one side of the tool and is pushed out from inside the work tool at least partially laterally from the air intake 230 through a first air outlet 245 formed on the other side of the tool.

[0048] A portion of the airflow drawn into the work tool through the air inlet 230 is directed through an air conduit to a second section 120, where it is used to cool the electrical storage device and, optionally, a portion of the electrical control circuit. Referring to Figure 2B, for example, this portion of the airflow is directed downward from the fan and then rearward within the tool towards the battery storage section 150 before exiting the work tool through a second air outlet 250 formed in the second section 120 of the tool.

[0049] It should be understood that when the fan is rotating in reverse, the airflow can also be directed in the opposite direction. That is, the air outlets 245 and 250 can also be used to draw cool air from the environment into the work tools 100 and 200, and the air intake 230 can be reused to allow hot air to exit the work tools instead.

[0050] Referring to Figure 10A, a portion 160 of the airflow 160 that is directed downward from the fan and then backward within the tool also exits the work tool through a third air outlet 251 formed within the battery compartment 150. This third outlet is primarily positioned to cool the battery housed in the battery compartment 150.

[0051] Figures 3A and 3B show several embodiments of the disclosed work tool, the first part 110 comprising a thermal conductive support arm 240 arranged to support a circular cutting tool 130 at a first end 241 of the support arm and an electric motor 140 by a support surface 330 of 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 mechanism, such as a belt drive or a combination of a belt drive and a geared transmission. The belt is not shown in Figure 3A, only the belt pulley is shown. The support surface 330 represents a relatively large interface area between the motor 140 and the support arm 240, allowing a considerable amount of heat transfer from the motor to the support arm material, provided that at least the electric motor includes a corresponding surface for interface with the support surface. This heat is then dissipated through one or more cooling flanges 320 formed on the support arm 240. Therefore, the support arm 240 includes one or more cooling flanges 320 arranged to dissipate heat from the electric motor 140 via the support surface 330.

[0052] The support arm 240 is the arm of the cutting tool and may be similarly referred to as the cutoff arm 240.

[0053] This heat transfer device improves heat dissipation from the motor by utilizing the flow of cooling air more efficiently to move heat away from the motor.

[0054] The higher the thermal conductivity of the support arm, the more efficient heat dissipation becomes. According to some embodiments, at least some parts of the support arm are formed from a material having a thermal conductivity of more than 100 watts / meter-kelvin (W / mK). For example, at least part of the support arm may be formed from aluminum with a thermal conductivity of approximately 237 W / mK. Iron or steel is another option that provides a desirable thermal conductivity. The support arm can also be formed from a variety of materials. That is, one high thermal conductivity material such as copper, magnesium, or aluminum can be used for the cooling flange, while another material such as cast iron or steel can be used to provide general structural support.

[0055] Figures 14A–14C and 15 show details of an exemplary support arm 240, which is arranged to support a circular cutting tool 130 at a first end 241 of the support arm and to support an electric motor 140 by a support surface 330 of a second end 242 of the support arm opposite the first end 241. Figure 14A shows a diagram of the support arm 240 and its internal space 340. Figure 14B shows a first cross-sectional view along line AA, and Figure 14C shows a second cross-sectional view along line BB. The motor 140 comprises a motor shaft extending through the motor housing 141 in a known manner.

[0056] The first end 142 of the shaft is configured to hold a pulley for driving the circular cutting tool 130. Figure 15 shows a support arm 240 in which the drive pulley and drive belt for driving the circular cutting tool 130 are in place.

[0057] The second end 143 of the motor shaft is configured to drive the fan 145. The example of the fan 145 shown in Figure 14B is a typical axial flow fan. Another, more advanced example of the fan 145 is discussed below in relation to Figures 11-13.

[0058] Optionally, the support arm 240 is configured to at least partially surround the electric motor 140, thereby protecting the motor and improving the cooling efficiency of the airflow 1330 passing through the motor. For this purpose, the support arm 240 has a cup-shaped recess, as detailed in Figure 10C, with a support surface 330 forming the bottom of the recess, and a cylindrical wall 350 extending from around the support surface 330 and surrounding the motor housing 141 of the electric motor 140 when the motor is supported on the support surface 330. The motor 140 is positioned to be securely bolted to the support surface 330 via bolt holes 335, thereby ensuring good heat conduction and mechanical integrity between the motor 140 and the support arm 240. A slot is formed between the cylindrical wall 350 and the motor 140, i.e., the recess wall 350 is radially spaced away from the motor housing. This slot is positioned to guide the cooling airflow 1330 from the fan 145 through the motor 140. The airflow 1330 flows laterally from the fan 145 through the support arm 240 to cool the electric motor 140. The cooling airflow 1330 then passes through the opening 310 into the internal space 340 and then exits through the first air outlet 245 shown in Figure 2B.

[0059] In some embodiments, at least 20% of the volume of the electric motor 140, i.e., the volume of the electric motor including its housing 141, is enclosed by the support arm 240. This means that the cylindrical wall 350 extends from the support surface 330 at a distance 144 to enclose at least 20% of the volume of the motor housing 141. Thus, the motor is optionally largely embedded in the support arm, or completely embedded as shown in Figures 14A-14C. This improves the structural integrity of the motor and support arm assembly and improves heat transfer from the electric motor. Cooling of the electric motor 140 is also improved by a slot formed between the cylindrical wall and the electric motor housing, which works in cooperation with the heat-conductive support arm and cooling flange to efficiently cool the electric motor.

[0060] The support arm 240 and the electric motor 140 may also be formed integrally, at least partially. This means that a portion of the electric motor 140 may be shared with the support arm 240. For example, a portion of the support arm 240 may constitute part of the electric motor housing, such as a motor cable facing the support arm. The common portion shared between the support arm 240 and the electric motor 140 may be machined or molded, for example. Optionally, the electric motor shaft may support the surface of the support arm, improving mechanical integrity.

[0061] It should be noted that the support arm and electric motor features, which are at least partially integrally formed, can be advantageously combined with other features disclosed herein, but are not dependent on any of the other features disclosed herein. Accordingly, a support arm 240 and electric motor 140 assembly for a work tool 100 is disclosed herein, in which the support arm and electric motor are at least partially integrally formed.

[0062] Referring to Figure 2B, the first part 110 optionally includes a belt guard 115 configured to surround an internal space 340. As described above, a portion of the cooling airflow is configured to be directed into the internal space 340, thereby raising the air pressure within the belt guard 115 internal space 340 above the ambient air pressure level. The internal space 340 is separated on one side by a support arm (described below in relation to Figures 3A and 3B) and on the other side by the belt guard 115, which in turn serves as a lid positioned to engage with the support arm to protect the drive belt in particular. The belt guard 115 includes an air outlet 245 through which the cooling airflow exits the internal space. This air outlet 245 is configured to have a region such that the air pressure within the belt guard 115 internal space 340 rises above the ambient air pressure level by a desired amount.

[0063] The increase in air pressure within the internal space 340 means that airflow will enter the internal space 340 not only through the air outlet 245 but also through all openings, i.e., cracks, etc. This means that water, dust, debris, and slurry will have to overcome this airflow to enter the interior. This reduces the accumulation of unwanted materials within the work tool.

[0064] Water in the internal space 340 is undesirable because it can cause the belt drive to slip. An increase in air pressure within the internal space 340 of the belt guard 115 means less water can enter the internal space, which is an advantage. As a result, the belt requirements can be reduced, for example, allowing the use of a belt with fewer ribs.

[0065] As described above, a portion 160 of the cooling air flow leading from the first portion 110 to the second portion 120 may pass through a bellows or other flexible airflow conduit 170 positioned between the first portion 110 and the second portion 120. An example of such a bellows 10 is shown in detail in Figure 4.

[0066] According to some embodiments, the bellows 170 has a Shore hardness value, or Shore hardness, between 10 and 70, preferably between 50 and 60, as measured with a durometer type A according to DIN ISO 7619-1.

[0067] The bellows 170 optionally includes poka-yoke functions 410, 420. These poka-yoke functions include at least one projection 410, 420 configured to enter corresponding recesses formed in the first part 110 and / or the second part 120, thereby preventing the bellows from being incorrectly assembled with the first part 110 and the second part 120.

[0068] The bellows 170 also optionally includes at least one thickened edge portion 430, 440. Each such edge portion is configured to fit into a corresponding groove formed in the first portion 110 or the second portion 120, thereby securing the bellows 170 to the first or second portion, similar to a sail leech that fits onto the mast. Figures 5 and 6 schematically show the bellows attached to the first and second portions, respectively, by the edges.

[0069] The bellows shown in Figure 4 is constructed with a symmetrical shape around a plane of symmetry 450 parallel to the extending direction of the edges 430 and 440. Therefore, advantageously, the bellows can be assembled with the first and second parts regardless of which side of the bellows is facing upwards. That is, the bellows can be rotated 180 degrees around the axis of symmetry 460 and assembled with the first and second parts.

[0070] Figures 7A to 7C schematically show an embodiment of a battery housing 150 in which the battery housing is equipped with 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 front edge portion 750 positioned to fit into a recess 760 formed in an electrical energy source 220, locking the electrical energy source in place. The front edge portion 750 has an arc shape corresponding to the curvature of a circular segment having a radius 740 corresponding to the distance from the front edge portion 750 to the center of the shaft 720. The recess 760 formed in the energy source 220 comprises a surface 770 configured to engage with the front edge portion 750, and the surface 770 has an arc shape that matches the shape of the front edge portion 750.

[0071] In this way, once the electrical energy source 220 is received into the battery compartment 150, the locking member becomes inactive and simply follows the electrical energy source as it enters the compartment. This step of inserting the electrical energy source 220 into the compartment 150 by moving it in the insertion direction 701 is schematically shown in Figures 7A and 7B. Next, the locking member 710 swings into the recess 760 that prevents the battery from retracting from the battery compartment. The locked position is shown in Figure 7C. In particular, the arc shape of the leading edge 750 allows the locking mechanism to rotate from the locked position with less resistance, even if there is some friction between the leading edge 750 and the surface 770 positioned to engage with the leading edge 750.

[0072] The locking member is spring-biased and positioned toward the locked position, and is operable by a lever or push-button mechanism as described below in relation to Figures 8 and 9.

[0073] In the manner described above, it will be understood that any number of locking members, from a single locking member to multiple locking members, can be arranged in the battery compartment.

[0074] In some embodiments, the battery housing 150 includes at least one elastic member 780 positioned to push the electrical energy source into a locked position, i.e., to push the electrical energy source in the direction opposite to the insertion direction 701. When compressed by the electrical energy source, the elastic member 780 pushes the electrical energy source and ejects it from the battery housing 150. This pressing force increases the contact pressure between the leading edge 750 and the surface 770 positioned to engage with the leading edge 750, thereby improving the retention effect on the electrical energy source.

[0075] In one example, the user inserts the battery into the battery compartment in the insertion direction. Once the battery is fully inserted, it contacts the elastic member 780, and the locking member 710 enters a recess 760 formed in the electrical energy source 220, locking the electrical energy source in place. When the elastic member is compressed by the battery, it is pushed back in the opposite direction to the insertion direction. This pressing force from the elastic member increases the contact force between the leading edge 750 of the locking member and the surface 770 configured to engage with the leading edge 750, thereby more securely holding the battery in place.

[0076] The elastic member 780 optionally includes an elastic material member, a compression spring, and / or a leaf spring.

[0077] The elastic member 708 also discharges the electrical energy source 220 from the battery compartment 150 over a short distance when the electrical energy source is released by the locking mechanism 700. In this way, when the push button mechanism 810 is operated to release the battery, the battery is discharged from the battery compartment 150, making it easy to grasp and pull out of the battery compartment.

[0078] Figure 7C schematically shows an example of such an elastic member 780. The elastic member presses 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 with the recess 760. The arrangement of the elastic member 780 and the locking member 710 on opposite sides S1, S2 of the electrical energy source 220 generates a torsional motion 795 or rotational moment, which further increases the holding effect by increasing friction between the battery and the wall of the battery compartment in a manner similar to stacked cupboard or desk drawers. This further improvement in the holding effect reduces vibrations caused by the battery as it is held more tightly within the battery compartment.

[0079] Figure 8 shows an exemplary work tool 800 including a battery locking mechanism 700. The locking member 710 is rotatably supported on the shaft 720 and can rotate about the pivot axis 820. Using the push-button mechanism 810, the operator can rotate the locking member 710 so that it exits the recess, thereby allowing the battery to be removed in direction 702.

[0080] In some embodiments, the locking member 710 is spring-biased toward the locked position. Therefore, when the electrical energy source 220 is inserted into the recess 150, the locking member 710 snaps into the locked position. The spring biasing force can be overcome by the push-button mechanism 810 when removing the electrical energy source from the battery compartment.

[0081] Figure 9 shows details of the battery locking mechanism 700 of the battery compartment 150. This battery locking mechanism can be used in various types of tools, such as polishing tools, grinders, chainsaws, drills, and cutting tools. Therefore, the battery locking mechanism disclosed herein is not limited to use in the cutting tools described above in relation to Figures 1-8.

[0082] The battery lock mechanism 700 shown in Figure 9 comprises a locking member 710 that is rotatably supported on a shaft 720 and optionally spring-biased to the locked position as described above. The locking member has a leading edge 750, which is configured to enter a recess 760 formed in the electrical energy source 220 to lock the electrical energy source in place, as described above in relation to Figures 7A to 7C. The leading edge 750 may have an arc shape with a curvature corresponding to a circular segment with a radius of 740 corresponding to the distance from the leading edge 750 to the center of the shaft 720. The recess 760 formed in the energy source 220 comprises a surface 770 arranged to engage with the leading edge 750. This surface 770 has an arc shape that coincides with the leading edge 750. In particular, the battery lock mechanism 700 shown in Figure 9 comprises two locking members 710 separated by a distance. This dual arrangement of locking members improves the robustness of the lock mechanism 700.

[0083] Therefore, as described in relation to Figures 7A to 7C, an electrical energy source such as a battery can be inserted into the battery housing, i.e., into the housing 150 shown in Figure 9, in the insertion direction 701. At some point, the locking member can enter a locked position, i.e., enter into the recess 760. In this position, the battery is prevented from moving in the opposite direction 702 to the insertion direction 701. However, there may be some looseness and it may not be securely fixed. To improve the battery locking mechanism and to better hold the electrical energy source in place, one or more elastic members 780, such as a compression spring or rubber bushing, are placed in the battery housing 150 and / or the electrical energy source to press against the electrical energy source when it is fully inserted into the housing. The pressing force increases the contact force between the leading edge 750 and the surface 770 configured to engage with the leading edge. This increased contact force increases friction, making it easier to hold the electrical energy source in place.

[0084] In some embodiments, at least one elastic member 780 and a battery locking mechanism 700 are located on opposite sides S1, S2 of the battery housing 150, i.e., there is a plane 910 dividing the battery housing into two parts, the elastic member 780 being included in one part and the battery locking mechanism being included in the other part. This means that one or more elastic members push the battery source from a certain direction, causing a torsional motion 795 or torque. This torsional motion can be likened to a drawer that latches into a cupboard or desk. The electrical energy source is prevented from rattling and is securely fixed by the battery housing 150.

[0085] Figures 10A and 10B show an exemplary work tool 1000 that includes a special type of fan 145. This fan comprises a member, preferably disc-shaped but not necessarily so, positioned on the axis of an electric motor 140, which also constitutes the fan's axis of rotation. The member extends in a plane perpendicular to the axis of rotation and comprises two different types of fan sections. The first section functions as an axial fan, pushing cooling air 201 laterally across the work tool 1000 to cool the electric motor 140. The second section of the fan functions as a radial fan, also called a centrifugal fan, and, in conjunction with a fan scroll that coincides with the radial fan section, pushes cooling air downward and delivers it to the second section of the work tool. The fan 145 is schematically shown in Figure 11, and an example of the fan is shown in Figure 12, which shows the direction of rotation 1130 and the axis of rotation 1140. Figure 11 also shows a direction 1145 referred to as “radially outward” from the axis of rotation 1140.

[0086] Figure 10A shows an example of a tool configured, according to several embodiments, to have a portion 160 of the cooling airflow from the first portion 110 to the second portion 120 enter an electrical energy source 220 through a third outlet 251 located inside the battery housing 150. This connection to the electrical energy source improves cooling efficiency by improving the cooling of cells in the battery, etc.

[0087] The fan 145 comprises an axial fan portion 1110 circumferentially arranged around the fan 145, i.e., along the fan disk boundary as shown in Figures 11 and 12, and a radial fan portion 1120 located in the center of the fan 145, i.e., radially inward from the axial fan portion as shown in Figures 11 and 12. Thus, the axial fan portion is located radially outward 1145 in the extension plane from the rotating shaft 1140. The axial fan portion 1110 is arranged to generate a flow of cooling air 1330 for cooling the electric motor 140, and the radial fan portion 1120 is arranged to generate a portion 160 of the flow of cooling air from the first portion 110 to the second portion 120 for cooling the electric storage device.

[0088] An axial fan has blades that force air to move parallel to the shaft on which the blades rotate, i.e., the axis of rotation. This type of fan is used in a wide range of applications, from small cooling fans for electronic equipment to huge fans used in wind tunnels. Axial fans are particularly well-suited for generating large airflows within straight tubular conduits, such as when cooling an electric motor 140.

[0089] Radial fans, or centrifugal fans, use centrifugal force supplied from the rotation of an impeller to increase the kinetic energy of air / gas. As the impeller rotates, gas particles near the impeller are released from the impeller and move towards the walls of the fan housing. The gas is then guided to the outlet by the fan scroll. Compared to axial fans, radial fans are better at pushing cooling air through pressure-passing air conduits with curved, narrow passages, in the case of air conduits that enter the second part and pass towards the battery housing 150.

[0090] In some embodiments, the axial fan and the radial fan are formed as separate components mounted on the same motor shaft.

[0091] The radius of the Radian may sometimes correspond to the radius of the electric motor cable.

[0092] The relationship between the radius of the radial fan and the radius of the fan can be on the order of 50-70 percent.

[0093] Therefore, advantageously, the fans shown in Figures 10 to 13 provide both efficient motor cooling and efficient cooling of tool components in the second part, such as the control unit and electrical energy source. This is achieved by providing two types of fans in a single fan component.

[0094] Figure 10C shows a more detailed view of a portion of the support arm, which includes one or more cooling flanges 320 positioned to dissipate heat from the electric motor 140 via the support surface 330. An opening 310 for introducing air into the internal space 340 can also be seen. An axial flow fan portion 1110 cools the electric motor 140 by passing air through the motor and pushing it out through these openings.

[0095] Fan 145 can optionally be assembled in a fan housing 1010 as illustrated in Figure 13. The fan housing includes at least one opening 1310 located around the rotating shaft 1140 and radially outward to receive a flow of cooling air 1330 from an axial fan section 1110 for cooling an electric motor 140. The fan housing also includes a fan scroll 1320 located in the center of the housing, which interfaces with the radial fan section 1120 to direct a portion 160 of the cooling air flow from the first section 110 to the second section 120 to cool the electric storage device.

[0096] Figure 13 also shows grooves 1340 and recesses 1350 for receiving the bellows 170 having the edge 430 and poka-yoke function 410 shown in Figure 4.

[0097] The fan described in relation to Figures 10A, 10B, 11, 12, and 13 is not applicable only to the types of work tools disclosed herein. Conversely, this fan can be advantageously used with any type of work tool that requires a first and second flow of cooling air. Accordingly, a fan 145 for handheld work tools 100, 200, 800, and 1000 is disclosed herein. The fan 145 extends in a plane perpendicular to the fan's axis of rotation 1140. The fan comprises a radial fan portion 1120 centrally located on the fan 145 with respect to the axis of rotation 1140 and an axial fan portion 1110 located radially outward 145, wherein the axial fan portion 1110 is configured to generate a first flow of cooling air for cooling a first handheld work tool member, and the radial fan portion 1120 is configured to generate a second flow 160 of cooling air for cooling a second handheld work tool member.

[0098] Optionally, the axial fan section 1110 has an annular shape centered on the rotating shaft 1140, and the radial fan section 1120 has a disc shape centered on the rotating shaft 1140.

[0099] Also disclosed herein is a handheld work tool 1000 comprising a fan and a fan housing 1010, as described in relation to Figures 10 to 13. The fan 145 is assembled within the fan housing 1010, and the fan housing comprises at least one opening 1310 positioned around the periphery of the fan housing and radially outward from the rotation axis 1140 of the fan 145, receiving a first flow of cooling air from an axial fan section 1110 for cooling a first handheld work tool, and the fan housing also comprises a fan scroll 1320 positioned in the center of the fan housing and interface with a radial fan section for guiding a second flow 160 of cooling air for cooling a second handheld work tool member.

[0100] Figure 16A shows details of an optional connector configuration 1600 for a water hose, preferably mounted near a rear handle 195 that is easily accessible to the operator for attaching and detaching the water hose. The connector configuration 1600 comprises a water hose connector portion 1610, shown here as a nipple, i.e., a male connector portion, for a water hose quick connector system facing rearward from the circular cutting tool 130. The connector nipple 1610 is fixedly mounted to the machine housing by a bracket 1620 so that the water hose connector portion 1610 is held fixedly in relation to the work tool. The same technical effect and benefits can also be obtained by fixing a female water hose connector portion to the work tool with a similar bracket. The water hose 1630 extends from the connector portion 1610 toward the cutting tool 130. The water hose 1630 is positioned at least partially embedded in the tool housing to protect the water hose from damage during use of the tool 100.

[0101] Known water hose connector configurations often include a hose segment between the tool bracket and the connector section (male or female connector section). This means that connecting and disconnecting the water hose with one hand is difficult. However, because the connector nipple 1610 is fixedly mounted to the machine housing by the bracket 1620, the connector configuration 1600 allows for the connection and disconnection of a water hose to supply water to the cutting tool 130 with one hand during operation. The connector section is securely supported by the machine housing in an easily accessible and immobile location. For example, an operator can hold the tool with one hand by the front handle 190 and connect the water hose with the other hand. The connector section 1610 can be adapted to interface with any quick connector system on the market, such as the Gardena® water hose system.

[0102] The water hose connector configuration 1600, comprising the connector portion 1610 and the bracket 1620, can be implemented on any power tool requiring a water supply, and is not limited to the specific tools discussed herein.

[0103] Figures 16B and 16C show more detailed diagrams of the connector configuration 1600. Figure 16B is a diagram corresponding to Figure 16A, and Figure 16C shows the connector configuration 1600 from the opposite viewpoint. The connector portion 1610 and the bracket 1620 are preferably integrally formed, i.e., machined or molded from a single piece of material such as a piece of plastic or metal. An internal nipple 1640 for attaching a water hose 1630 may be located on the opposite side of the connector portion 1610 for convenient assembly of the connector configuration on a handheld work tool.

[0104] Figures 17A and 17B show details of an exemplary battery compartment 150. An electrical energy source, such as a battery, can be inserted into the battery compartment 150, i.e., the compartment 150 also shown in Figure 9, in the insertion direction 701. Figure 17A is a view opposite to the insertion direction 701, and Figure 17B is a view of the compartment 150 in the insertion direction 701. For example, the locking member 710 discussed above in relation to Figure 9 can be seen in Figures 17A and 17B. The battery, which will be discussed in more detail below in relation to Figures 18A to 18C, optionally includes a rear surface formed as a handle to simplify both the insertion and removal of the battery from the battery compartment 150.

[0105] The batteries used to power heavy cutting tools, such as the work tools described here, are typically very heavy. Therefore, the batteries need to be held in the battery compartment 150 in a robust and reliable manner. For this purpose, the battery compartment 150 is equipped with a battery holding mechanism specially adapted to support heavy batteries, i.e., weights on the order of 5 kg, between 3 and 7 kg.

[0106] The battery compartment 150 extends laterally through the housings of the tools 100 and 200, as discussed above, and here defines the volume for receiving the battery. The volume is divided by a rear wall Rw and a front wall Fw, the rear wall Rw is positioned toward the rear handle 195 of the tool 100, and the front wall Fw is positioned toward the front of the tool 100, i.e., toward the cutting tool 130. The bottom surface Bs and the top surface Fs also divide the volume. The example volume in Figures 17A and 17B is a rectangle with rounded corners.

[0107] The battery holding mechanism includes a support heel 1710 located in the central portion of the side wall of the battery compartment, more specifically the rear wall Rw closest to the rear handle 195. The heel 1710 is elongated, and its direction of extension aligns with the direction of battery insertion into the battery compartment 150, extending laterally through the battery compartment. When the machine is resting on the ground support member 280, the support heel 1710 is parallel to the ground. Also, when the tool 100 is held in its normal operating position, the support heel is parallel to the ground and thus supports the battery against gravity. It will be understood that the support heel 1710 can also be located on the front wall, i.e., either the front wall and / or rear wall of the battery compartment. The batteries illustrated in Figures 18A-18C and described below have corresponding grooves that coincide with the support heel.

[0108] According to some embodiments, the support heel 1710 has a metal exterior to enhance mechanical integrity. That is, the support heel 1710 is optionally constructed with an outer metal layer to enhance mechanical robustness.

[0109] In some other embodiments, the battery compartment also includes an upper dovetail groove 1720 and a lower dovetail groove 1730 for supporting the battery within the battery compartment 150. The dovetail grooves are positioned to engage with corresponding raised structures of the battery, and the battery can be inserted into the battery compartment 150 in the insertion direction 701 into a position that engages with the dovetail grooves. Thus, the support heel 1710 and the dovetail grooves 1720, 1730 work together to support the battery within the battery compartment in a safe and robust manner. The dovetail grooves 1720, 1730 have the function of guiding the battery when it is inserted into the battery compartment 150 and preventing it from getting stuck when it is removed from the battery compartment 150.

[0110] In some embodiments, the dovetail grooves 1720, 1730 are covered with metal to increase their mechanical strength. That is, the grooves are reinforced with a metal lining layer to enhance their mechanical robustness.

[0111] Figure 17B also shows two elastic members 780 positioned to push the battery into a locked position, that is, to push the electrical energy source in the opposite direction to the insertion direction 701, as discussed above in relation to Figure 7C.

[0112] A contact strip 1740 extending in the insertion direction 701 is positioned in the battery housing 150 and mates with a corresponding electrical connector configured in the battery slot.

[0113] A battery 1800, as shown in Figures 18A-18C, for insertion into the battery compartment 150 is also disclosed herein. The battery 1800 has a weight of 3-7 kg and comprises a groove 1810 located on one side of the battery to mate with a corresponding support heel 1710 located on the wall of the battery compartment 150. The groove is optional and has an initial bevel to facilitate mating with the support heel 1710. The battery 1800 further comprises an upper ridge structure 1820 and a lower ridge structure 1830 on the opposite side of the battery compared to the groove 1810 for mating with corresponding dovetail grooves 1720, 1730 of the battery compartment 150, as shown in Figure 18. Thus, the battery 1800 is configured to be inserted into the battery compartment 150 as described in relation to Figures 17A and 17B.

[0114] The battery 1800 includes at least one recess 760 configured to receive each of the locking members 710 of the battery locking mechanism 700, as discussed above. The locking member has an arc-shaped leading edge 750, and the recess 760 includes a surface 770 positioned to engage with the leading edge 750. The surface 770 has an arc shape that coincides with the leading edge 750. As shown in Figure 18A, two recesses are advantageously positioned on either side of the elongated support heel 1710.

[0115] The battery 1800 illustrated in Figures 18A to 18C also comprises one or more electrical connectors 1840 that are protected and positioned in slots extending in the insertion direction to mate with corresponding contact strips 1740 located in the battery housing 150.

[0116] Optionally, the battery 1800 includes a front F1 facing the insertion direction 701 when the battery 1800 is inserted into the battery compartment 150, and a rear F2 opposite to the front, the rear being formed as a handle 1850 that can be held with one hand.

[0117] The battery also includes an electrical connector 1840 configured in a slot that extends in the insertion direction to mate with a corresponding contact strip 1740 located in the battery compartment 150. This protects the electrical connector from mechanical shock.

[0118] To facilitate battery cooling, as shown in Figure 18C, there is an air outlet 1860 located on the top of the battery and an air inlet located on the bottom of the battery, which is in fluid contact with it. Thus, the airflow 160 from the fan 145 is guided through the battery 1800, allowing the battery cells to be cooled more effectively.

[0119] The battery and battery compartment described in relation to Figures 17 and 18 can also be used in other handheld tools. Therefore, the functions disclosed in relation to the battery compartment and battery are independent of other specific functions of the tools described herein.

[0120] Figure 19 shows an exemplary handheld electric cutting tool 1900 comprising a first part 110 and a second part 120 arranged to be vibrationally insulated from each other by one or more damping members 170, 1910, which can optionally be combined with one or more elastic members, such as the metal spring 210 shown in Figures 2A and 2C.

[0121] A potential problem with the type of handheld cutting tool discussed herein is that the cutting disc 130 becomes slightly elliptical during use. An excessively elliptical cutting disc is undesirable because it can impair cutting performance and cause discomfort to the operator. An elliptical cutting disc is also undesirable because it is associated with an increased risk of kickback. An example of an elliptical cutting disc 130 is shown in inset 1920 of Figure 19. The elliptical cutting disc is associated with variations in the “diameters” D1, D2 of the disc as measured on the disc. That is, D1 and D2 in Figure 19 are not equal and differ by a non-negligible amount. Although the measured values ​​D1 and D2 may be considered as half of the semi-minor and semi-major axes of the ellipse, an elliptical cutting disc is not perfectly elliptical and often has an uneven radius along its circumference.

[0122] This problem with elliptical cutting discs tends to be more pronounced when the angular velocity ω of the cutting disc is low, such as when the cutting tool is operated at less than approximately 3600 rpm, as measured at the rotation axis of the cutting disc 130. Handheld electric cutting tools, such as the tools 100, 200, 800, 1000, and 1900 discussed herein, which include first and second parts that are vibrationally isolated, are particularly susceptible to the elliptical cutting disc problem.

[0123] According to some embodiments, the handheld electric cutting tools described herein, particularly in reference to Figures 19 to 22, are configured to operate at a cutting disk rotation speed ω of less than 4000 rpm, preferably about 3200 rpm.

[0124] A solution to the elliptical disk problem is simply to increase the cutting disk's rotational speed ω to, for example, a speed exceeding 4000 rpm. However, such high cutting disk speeds are undesirable for many reasons.

[0125] In dry cutting, that is, when cutting concrete or stone with a handheld electric cutting tool without adding fluid such as water to the cutting zone, if the speed is too high, it becomes very difficult to efficiently collect the dust generated by the cutting disc. Therefore, it is desirable to reduce the speed of the cutting disc in dry cutting applications. The appropriate cutting disc speed for dry cutting applications is usually on the order of approximately 3100 to 3300 rpm, preferably approximately 3200 rpm.

[0126] A high cutting disc speed also means that the cutting disc stores a lot of energy during operation. This makes it difficult to quickly reduce the speed of the cutting disc by applying the brakes, such as during kickback. Therefore, for safety reasons, it may be desirable to limit the speed of the cutting disc to approximately 3100-3300 rpm, for example, around 3200 rpm.

[0127] Furthermore, electric cutting tools may face the challenge of generating sufficient torque for efficient cutting if the cutting disc speed is too high. For this reason, it is sometimes preferable to set the cutting disc speed ω to around 3100-3300 rpm.

[0128] It will be understood that the cutting disc speeds mentioned above are merely examples and depend on many factors, such as the type of tool, the size of the cutting disc, and the specifications of the electric motor.

[0129] It has been recognized that the problem of elliptical cutting discs can be mitigated when damping members are optionally placed between the first part 110 and the second part 120 in combination with metal springs for efficient vibration isolation. These damping members differ from the conventional spring-based vibration isolation elements typically used in this type of tool, as they are formed from an elastic material associated with a damping coefficient. The damping members suppress the vibrational behavior between the two masses of the handheld electric cutting tool, including the first and second parts, which are positioned vibrationally isolated from each other. This suppression mitigates the tendency for elliptical cutting blades to form on low-speed cutting discs. This is because, at least in part, without the damping members, the two masses of a vibration-free cutting tool operating at a particular cutting disc speed could cause vibrational behavior that exerts different cutting pressures on different sections of the cutting blade. In other words, the rotation and vibrational motion of the cutting disc may be synchronized. When the system including the first part 110 and the second part 120 enters this type of vibrational state, an elliptical cutting disc can result.

[0130] Cutting tools powered by combustion engines, in principle, are equipped with elastic members in the form of metal springs to suppress vibrations between the motor, the cutting disc, and the handle. However, these springs are not damping members in the sense that they suppress the vibrational behavior of one mass relative to another. Simple harmonic motion is often modeled by a mass on a spring, and the restoring force follows Hooke's law and is directly proportional to the displacement of the object from the equilibrium position. A system that follows simple harmonic motion is called a simple harmonic oscillator. This type of vibrational behavior can be mitigated by adding a damping effect to the system. This can be achieved by adding a damping member (often denoted by c) associated with a damping coefficient or a configuration that limits the stroke length of one part relative to the other. The damping ratio is an index that represents the rate at which vibrations decay from one "bounce" to the next. Damping ratios range from undamped (ζ=0), low-damped (ζ<1) to critical-damped (ζ=1) and over-damped (ζ>1).

[0131] Figure 19, also with reference to Figure 1, shows a handheld electric cutting tool 1900 comprising a first part 110 and a second part 120 arranged to be vibrationally isolated from each other. The first part 110 comprises an arm 116 positioned to support a cutting disc 130 (shown in inset 1920 of Figure 19) and an electric motor 140 positioned to drive the cutting disc. The second part 120 comprises 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 configured to power the electric motor 140. An example of this battery is described above in relation to Figures 18A-18C.

[0132] In particular, one or more damping members 170, 1910 are positioned between the first portion 110 and the second portion 120, and at least one of the damping members 170, 1910 is formed of an elastic material related to the damping coefficient.

[0133] The damping members are positioned to suppress or interfere with the vibration of the second portion 120 relative to the first portion 110. This reduces the risk of the resulting elliptical cut disc.

[0134] In some embodiments, at least one damping member 170, 1910 is made of rubber, a resilient plastic material, closed-cell foam, or a resilient synthetic resin. Common to these damping members is the introduction of a damping coefficient into the resonance equation of a mechanical system comprising a first part 110 and a second part 120. This damping coefficient effectively suppresses the vibrational behavior of the first part relative to the second part. For example, a closed-cell foam collar may be positioned around a flexible air conduit 170 as shown in Figure 1, or the closed-cell foam collar may even constitute the flexible air conduit 170.

[0135] Preferably, since metal springs are more effective in vibrationally isolating the parts from each other, the first part 110 is vibrationally isolated from the second part 120 by one or more elastic elements 210 in addition to at least one damping member 170, where one or more elastic elements 210 include at least one metal spring. Thus, the combination of metal springs and damping members made of elastic material provides both efficient vibration isolation and a reduced risk of the cutting disc becoming elliptical during the operation of the cutting tool.

[0136] Figure 19 shows examples of two types of damping members that can be used independently or in combination. It should also be understood that this teaching includes other types of damping members that can be applied elsewhere between the first and second parts. For example, "between" can also be interpreted to include damping members that are attached to both the first and second parts but extend outside the slot 1930 formed between the first and second parts.

[0137] Figure 20 shows an example of two damping members 1910, 1920. The first damping member 170 is integrated with a bellows 2100 (shown in more detail in Figure 21) or other flexible air conduit positioned between the first section 110 and the second section 120. This bellows or flexible air conduit provides a damping coefficient and also acts to limit the stroke length related to the relative motion of the first section 110 with respect to the second section 120. As the first section 110 moves toward the second section 120 in direction C, as shown in Figure 21, the reinforcing element 1920, positioned on at least one side of the bellows, such as two or more sides of the bellows 2100, limits the compression of the bellows, thereby limiting the stroke length of the vibrational motion and hindering the vibrational operation.

[0138] The compression ratio related to the Shore hardness of the bellows can be adjusted by selecting the type of material used in the reinforcing element 1920, or by dimensionalizing the thickness of the material used in the element and the bellows. The compression ratio can also be adjusted by placing one or more cavities 1930 in the reinforcing element 1920, as shown in Figure 21. In one embodiment, the bellows 2100 is positioned between the first part 110 and the second part 120, and the bellows 2100 is associated with a Shore hardness value between 50 and 100, preferably between 65 and 90, as measured with a durometer type A in accordance with DIN ISO 7619-1. Thus, it will be understood that the Shore hardness and material thickness of the bellows can be adjusted as shown in Figures 4 and / or 21, by introducing a damping coefficient to the mass spring system to suppress vibration, introducing a stroke length limit to prevent vibration, or both, thereby reducing the occurrence of elliptical cutting discs in handheld electric cutting tools.

[0139] In another example, as also shown in Figure 20, at least one damping member 1910 is fixedly attached to one of the first portion 110 or the second portion 120 and positioned away from the other of the first portion 110 or the second portion 120. Thus, at least one damping member 1910 is positioned to limit the stroke length related to the relative motion of the first portion 110 with respect to the second portion 120. This damping member has a similar function to the reinforcing element 1920 described above in relation to Figure 21. It is positioned to limit the stroke length of the vibrational motion between the first portion and the second portion. A detailed view of the damping member 1910 is shown in Figure 22. In this example, it is integrally formed from a single elastic material and attached to the body of the first portion 110 or the second portion 120.

[0140] A low cutting disc speed, which can be maintained without the risk of the cutting disc becoming elliptical, allows for the advantageous implementation of an electric kickback protection mechanism. This is because a kickback protection mechanism based on braking by the electric motor 140 may be ineffective at very high cutting disc speeds. Thus, according to some embodiments, the electric motor 140 is configured to be controlled by a cutting tool control unit via a motor control interface. The control unit is configured to acquire data indicating the angular velocity of the cutting disc 130 and to detect a kickback condition based on a decrease in angular velocity. The control unit is also configured to control the electromagnetic brake of the electric motor 140 in response to the detection of a kickback condition.

[0141] Disclosed herein is a handheld electric cut-off tool for cutting concrete and stone by a rotatable cutting disc 130, suitable for powerful cutting tools involving considerable tool inertia, and to provide a kickback reduction function that responds quickly enough and has sufficient braking force. The cutting tool comprises an electric motor 140 arranged to be controlled by a control unit via a motor control interface. The control unit is configured to acquire data indicating the angular velocity of the cutting disc 130 and to detect kickback conditions based on a decrease in angular velocity. The control unit is also configured to control the electromagnetic brake of the electric motor 140 in response to the detection of a kickback condition, and optionally to actively adjust the energy extraction from the electric motor via the control interface during electromagnetic braking.

[0142] The detection mechanism is based on monitoring the angular velocity of the cutting disc 130. A kickback condition is detected if a sudden decrease in speed is observed, such as a significant delay in the electric rotor angle or the cutting disc angle. Immediately after the control unit detects a kickback event, the electric motor is forcibly braked to mitigate the effects of the kickback event. This braking actively controls the energy release from the electric motor to provide a strong braking force without damaging the electrical components of the cutting tool. This braking is facilitated by the fact that the cutting disc operates at a speed of less than 3500 rpm, for example, 3200 rpm, which is made possible by the presence of a damping member.

[0143] The kickback detection and braking of the cutting disc are often fast enough to stop the blade before it leaves the workpiece. Even if a kickback occurs, the energy transferred from the cutting disc 130 to the machine body is reduced to a level that mitigates the adverse effects of the kickback event. In particular, the electric motor is not simply disconnected from the power supply, as in many prior art documents. Rather, the energy intake from the electric motor is actively adjusted to provide a braking action strong enough to stop the kickback event.

[0144] See also Figure 1, Figure 23 shows a handheld electric cutting tool 2300 comprising a fan 145 configured to be driven by an electric motor 140 to generate a flow of cooling air 160, and electric storage devices 220, 1800, such as batteries, configured to power the electric motor 140. The cooling air conduit is positioned to guide the flow of cooling air 160 toward an outlet opening 1750 (see, for example, Figure 17B) formed in the wall of the battery housing 150. The outlet opening 1750 faces a corresponding inlet opening 1870 formed in the housing of the electric storage devices 220, 1800 to receive cooling air and thereby generate an air pressure above atmospheric pressure within the electric storage devices 220, 1800. Referring to Figure 24, which more schematically illustrates the cooling flow, the first slot section S1 is formed by the distance between the outlet opening 1750 and the inlet opening 1870 of the electrical storage device 220, and as a result, a first portion 2415 of the cooling air flow 160 leaks out of the cutting tool through the first slot section S1.

[0145] This first portion 2415 of the cooling airflow 160 generates air pressure within the first slot section, and any dirt and slurry entering the slots between the electric storage device 220 and the storage wall must overcome this air pressure. This has the advantage of preventing dirt and slurry from entering the slots and keeping the battery storage area clean. A clean battery storage area, free from dust and slurry buildup, makes it easier to insert and remove the electric storage device 220 from the tool.

[0146] In one example, the first slot section Ss1 is separated on one side by a guide means that guides the electrical storage device 220 into the storage section.

[0147] In some embodiments, the distance between the electrical storage devices 220, 1800 and the wall of the battery storage section 150 is between 0.5 mm and 2.0 mm, preferably about 1.0 mm. This distance may vary around the electrical storage device 220.

[0148] The electrical storage devices 220, 1800 may further comprise one or more electrical connectors 1840 arranged to mate with corresponding contact strips 1740 located in the battery housing 150. Examples of these electrical connectors are shown more clearly in Figure 18C. An opening in the housing of the electrical storage devices 220, 1800 is formed in connection with the electrical connectors 1840, and a second portion 2425 of the cooling airflow passes through the opening and leaks out to the outside of the cutting tool through a second slot section S2 formed between the electrical storage devices 220, 1800 and the wall of the battery housing 150. Thus, since the battery housing is not sealed around the electrical connectors 1840, overpressure of cooling air in the electrical storage device 220 generates an airflow that exits through the electrical connectors and passes through the second slot section. Again, dirt and slurry attempting to enter the slots must overcome this airflow exiting the machine through the slots. Such a thing rarely happens, as the leak is a considerable flow compared to the more diffuse movement of dust and slurry generated by the cutting operation. Therefore, the electrical connectors remain clean during operation and are free from slurry. This has the advantage that insertion and removal of the electrical storage device 220 is easier, especially when the connectors and guiding means are clean. The second slot section S2 may be demarcated by, for example, the upper raised structure 1820 and the lower raised structure 1830 shown in Figure 18C.

[0149] Finally, an air outlet 1860 is also formed within the housing of the electric storage device opposite the inlet opening 1870, forming a passage for cooling air to flow through the electric storage device. A third slot section S3 is formed by the distance between the air outlet 1860 and the wall of the battery storage unit 150, allowing a third portion 2435 of the cooling air flow 160 to leak out of the cutting tool through the third slot section S3. This third slot section also provides a passage for cooling air to leak out through the slot, thereby keeping the space between the top of the electric storage device 220 and the wall of the battery storage unit clean and free from dust and slurry.

[0150] Figure 25 schematically shows the mass distribution of the cutting tools and other work tools described above in relation to Figures 1 to 24. It was found that the weight distribution between the parts of a handheld electric cutting tool, which has a first part and a second part that are arranged to be vibrationally separated from each other, can be optimized in order to achieve more efficient cutting operations and at the same time reduce the discomfort to the operator caused by vibrations transmitted from the machine to the operator through the handle.

[0151] Vibration-damped gasoline-fueled cutting tools, i.e., tools powered by a combustion engine, are known. However, these known tools have an inefficient weight distribution between the handle and the combustion engine and cutting disc components. In some known gasoline-fueled cutting machines, the motor and arm weigh approximately 7550g, while the handle weighs approximately 2600g with an empty fuel tank and approximately 3500g with a full tank, resulting in a ratio of 2600g / 10150g (approximately 0.25) when empty and 3500g / 11050g (approximately 0.32) when full.

[0152] There is an advantage if the handle portion, i.e., masses M2 and M3 in Figure 25, is heavy enough to withstand vibrations transmitted through the damping and elastic elements mentioned above. However, the portion with the cutting blade, i.e., masses M1 and M4, should not be too light compared to the handle portion, as this would disrupt the balance of the tool.

[0153] Experiments and computer analyses have shown that the ratio of the second mass M2 to the sum of the first and second masses M1+M2 is preferably at least 0.3, preferably greater than 0.35, meaning the second mass must constitute a significant portion of the total mass of the cutting tool without the cutting disc and electrical storage device. The ratio M2 / (M1+M2) is, for example, about 0.38 for a 12-inch blade device and about 0.37 for a 14-inch blade device. However, the second mass M2 must 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 less than about 0.5, preferably less than about 0.6.

[0154] It was also 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 more preferably greater than 1.0. These ratios provide a well-balanced tool with excellent vibration damping capabilities.

[0155] Furthermore, it was found that the ratio of the sum of the second and third masses (M2+M3) to the total weight of the entire device including the electrical energy storage and cutting disc (i.e., M1+M2+M3+M4) should be at least 0.45, and preferably greater than 0.5. This ratio provides a stable tool with excellent vibration damping properties.

[0156] In summary, this specification discloses handheld electric cutting tools 100, 200, 800, 1000, 1900, and 2500, which include a first part 110 and a second part 120 arranged to be vibrationally isolated from each other. The first part 110 comprises an interface 2510 for holding a cutting tool 130 and an electric motor 140 configured to drive the cutting tool, and the first part is associated with a first mass M1, The second part 120 comprises a battery compartment 150 for holding an electrical storage device 220 configured to supply power to an electric motor 140, and a front handle 190 and a rear handle 195 for operating a cutting tool, the second part being associated with a second mass M2, where the ratio of the second mass M2 to the sum of the first and second masses M1+M2 is at least 0.3, preferably greater than 0.35.

[0157] Handheld electric cutting tools 100, 200, 800, 1000, 1900, and 2500 are disclosed, comprising a first part 110 and a second part 120 arranged to be vibrationally isolated from each other, a cutting tool 130, and an electric storage device 220. The first part 110 comprises an interface 2510 for holding a cutting tool 130 and an electric motor 140 configured to drive the cutting tool, the first part being associated with a first mass M1, and the cutting tool being associated with a fourth mass M4. The second part 120 comprises a battery compartment 150 for holding an electrical storage device 220 configured to supply power to an electric motor 140, and a front handle 190 and a rear handle 195 for operating a cutting tool, the second part being associated with a second mass M2, and the electrical storage device 220 being associated with a third mass M3. The ratio of the sum of the masses of the second and third members, M2+M3, to the sum of the masses of the first and fourth members, M1+M4, is at least 0.6, preferably more than 0.8, and more preferably more than 1.0.

[0158] Furthermore, handheld electric cutting tools 100, 200, 800, 1000, 1900, and 2500 are disclosed, comprising a first part 110 and a second part 120 arranged to be vibrationally isolated from each other, a cutting tool 130, and an electric storage device 220. The first part 110 comprises an interface 2510 for holding a cutting tool 130 and an electric motor 140 configured to drive the cutting tool, the first part being associated with a first mass M1, and the cutting tool being associated with a fourth mass M4. The second part 120 comprises a battery compartment 150 for holding an electrical storage device 220 configured to supply power to an electric motor 140, and a front handle 190 and a rear handle 195 for operating a cutting tool, the second part being associated with a second mass M2, and the electrical storage device 220 being associated with a third mass M3. The ratio of the sum of the second and third masses (M2+M3) to the sum of the total weight of the entire apparatus including the electrical energy storage and cutting disks (M1+M2+M3+M4) is at least 0.45, and preferably greater than 0.5.

[0159] The following table provides exemplary weight distributions that may be advantageously used with the handheld electric cutting tools discussed herein. Examples of two different battery sizes are included in the table, with the larger battery weighing approximately 5100g (indicated as M32) and the smaller battery weighing approximately 3000g (indicated as M31).

[0160] [Table 1]

[0161] According to some embodiments, the raised structures 1820, 1830 and the corresponding grooves 1720, 1730 may have shapes other than the dovetail shapes disclosed above. For example, the shapes may be rectangular, polygonal, or elliptical.

[0162] In some embodiments, the support heel (1710) is either attached to the wall (Rw, Fw) or incorporated into the wall (Rw, Fw). In the latter case, the support heel (1710) can be formed from the same material as the wall (Rw, Fw). [Explanation of symbols]

[0163] 100, 200, 800, 1000, 1900 Handheld Electric Cutting Tools 110 Part 1 115 Belt Guard 116 Arm 120 Part 2 130 Circular Cutting Tool 140 Electric motor 141 Motor Housing 145 Fans 150 Battery compartment 160 Part of the cooling air 170 Bellows, Flexible Air Flow Conduit 180 Cooling flange 190 Front handle 195 Rear handle 210 Elastic member 220 Electrical storage devices 240 support arms 245,250,251 Air outlet 260 Cutting Tool Interface 270 holder 280 Ground support member 310 Opening 320 Cooling Flange 330 Support surface 335 bolt holes 340 interior space 350 Cylindrical Wall 410,420 Poka-yoke function, protrusions 701 Insertion direction 708 Elastic member 710 Locking component 750 Front edge 760 recesses 770 Surface 780 Elastic members 1010 Fan Housing 1110 Axial fan section 1120 Radial fan section 1320 Fan Scroll 1600 Connector Configuration 1610 Connector section 1620 bracket 1630 Water Hose 1710 Support heel 1720 Upper groove 1730 Lower groove 1740 Contact Strip 1800 Electrical storage devices, batteries 1820 Upper raised structure 1830 Lower raised structure 1840 Electrical Connector 1850 Handle 1910, 1920 Damping member

Claims

1. A battery (1800) to be inserted into a battery compartment (150) of a work tool, wherein the battery (1800) comprises a groove (1810) located on one side of the battery for fitting into a corresponding support heel (1710) located on the wall of the battery compartment (150), and the battery further comprises an upper ridge structure (1820) and a lower ridge structure (1830) located on the opposite side of the battery from the groove (1810), wherein the ridge structures (1820, 1830) are configured to fit into corresponding grooves (1720, 1730) of the battery compartment (150).

2. The battery (1800) according to claim 1, comprising one or more electrical connectors (1840) protected and disposed in slots extending in the insertion direction so as to fit into corresponding contact strips (1740) disposed in the battery housing (150), wherein the electrical connectors are disposed between the upper raised structure (1820) and the lower raised structure (1830).

3. A work tool comprising a battery storage section (150) having walls (Rw, Fw) and an elongated support heel (1710), wherein the support heel (1710) extends in an extension direction across the work tool and in the direction (701) for inserting the battery into the battery storage section (150), and the support heel (1710) is configured to support the battery housed in the battery storage section against gravity.

4. The work tool according to claim 3, wherein the battery storage section (150) further comprises an upper groove (1720) and / or a lower groove (1730) disposed in the wall of the battery storage section to support a battery housed in the battery storage section, the upper groove and the lower groove being arranged to fit into corresponding raised structures of the battery, and the battery being inserted into the battery storage section (150) in a position where it fits into the grooves (1720, 1730).

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