Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
  • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
  • B25F5/008—Cooling means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B23/00—Portable grinding machines, e.g. hand-guided; Accessories therefor
  • B24B23/02—Portable grinding machines, e.g. hand-guided; Accessories therefor with rotating grinding tools; Accessories therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B23/00—Portable grinding machines, e.g. hand-guided; Accessories therefor
  • B24B23/02—Portable grinding machines, e.g. hand-guided; Accessories therefor with rotating grinding tools; Accessories therefor
  • B24B23/028—Angle tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
  • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
  • B25F5/02—Construction of casings, bodies or handles

Definitions

• the present invention relates to an electric tool, in particular a rechargeable electric tool for grinding workpiece materials, which grinds workpieces by making a top end tool rotate.
• handheld electric tools for performing grinding work such as angle grinders
• an electric motor installed in a tool housing to act as a source of driving power.
• a handle part for the person carrying out the work to grip is formed on the housing behind the electric motor.
• a gear transmission mechanism is arranged at a front part of the tool, while a detachable rechargeable battery is fitted at a rear part of the handle part to act as a power supply.
• the handle part is often constructed in the form of a tube, so that the user can grip it easily, and the battery is fitted at the rear part of the handle; as the demand for large-capacity batteries grows, battery size and weight are also increasing, but the weight of the battery will result in the centre of gravity of the electric tool being displaced from the optimal balanced position.
• An objective of the present invention is to provide an electric tool which has an optimized, balanced tool structure and is more ergonomic, to facilitate user operation.
• the present invention provides an electric tool comprising a tool housing, a motor having a rotating shaft, a motor housing accommodating the motor, a gearbox arranged at a front side of the motor, a main shaft supported by the gearbox and extending in a direction intersecting the rotating shaft.
• a battery accommodating part is mounted behind the motor housing and used to accommodate a rechargeable battery.
• a handle is mounted behind the battery accommodating part.
• the battery is mounted between the motor and the handle, thus optimizing the balance of the overall structure of the electric tool and avoiding interference between a user's hand and the battery, so the electric tool has better ergonomics.
• the battery accommodating part is assembled to the motor housing, thus the drive unit and wirings can be preassembled together, and the battery accommodating part can be replaced without removing the drive apparatus, so repairing is convenient.
• the electric tool further comprises a circuit board received in the tool housing and located adjacent to the motor housing. At least one air inlet is formed on the outer surface of the tool housing.
• the circuit board is located parallel to the rotating shaft of the motor and the air inlet is positioned opposite to the circuit board. Hence, external air flows past the circuit board along the most direct path, avoiding overheating of electronic devices on the circuit board to the maximum extent possible.
• the circuit board is located above the motor housing and the air inlet is formed on the tool housing above the circuit board.
• the wires connecting the motor and the circuit board would be shortest and the cooling path would be optimized.
• a fan is provided at a front end of the motor, and at least one air outlet is formed on the gearbox in front of the fan.
• a side of the battery accommodating part close to the motor housing is provided with a battery mounting part, and the battery is removably attached to the battery mounting part.
• the battery mounting part is close to a side of the motor housing so that the wires connecting the battery and the circuit board are shorter, helping to simplify the layout of wires and avoid generating an excessive amount of heat.
• the battery when the battery is mounted to the battery accommodating part by a mounting direction substantially parallel to the direction of extension of the main shaft.
• the battery suffers little interference; during cutting especially, it is undesirable for the battery accommodating part to strike the ground.
• insertion and withdrawal are easier in this direction.
• the battery accommodating part is substantially in the form of a cavity having an opening that is open in an upward direction, and two sides of the cavity comprise battery protection parts extending substantially along the longitudinal length of the battery. This not only makes mounting and removal of the battery convenient, but also ensures that the battery will not be damaged easily after being mounted to the electric tool, even if the electric tool is accidentally dropped.
• the battery comprises an unlock button for releasing the battery from the battery mounting part, the unlock button being at a higher position than the motor housing when the battery is mounted to the battery accommodating part, so that the battery can be easily withdrawn from the battery mounting part.
• the handle is rotatable, and a front end of the handle is connected to the rear of the battery accommodating part via a rotation mechanism.
• the rotatable handle helps the user to grip the tool better in various application scenarios.
• the handle is substantially in the form of a D shape extending in a front-rear direction.
• the D-shaped handle helps the user to grip the tool conveniently and reliably, and also helps to balance the overall structure of the electric tool.
• the handle rotates about a rotation axis X parallel to the direction of extension of the rotating shaft.
• the rotation mechanism has a locking part for locking a rotation angle
• the handle has at least three locking positions at -90 degrees, 0 degrees and 90 degrees relative to the rotation axis X thereof. It is extremely important that the handle can be kept in a locked state after rotating to the desired angle, to ensure that undesired rotation or shifting of the electric tool will not occur during operation.
• the electric tool is s also used for cutting applications in which a peripheral surface region of an abrasive or diamond disc is used to cut a material being processed.
• the handle of the electric tool of the present invention can rotate through 90 degrees, so is conveniently suitable for grinding applications or cutting applications.
• the electric tool is a grinding tool, in particular an angle grinder.
• an angle grinder is used for illustration.
• an electric tool 1 comprises a tool housing 21, and a motor 3 as a source of driving power.
• a motor housing 4 for accommodating the motor 3.
• the motor 3 has a rotating shaft 2 extending substantially in the front-rear direction of a tool main body; this rotating shaft 2 is an output shaft of the motor 3.
• a front side of the motor 4 is connected to a gearbox 6, within which gearbox 6 is comprised a gear transmission mechanism connected to a front end of the rotating shaft 2.
• the gearbox 6 supports a main shaft 5 extending in a direction intersecting the rotating shaft 2, i.e. the main shaft 5 extends substantially in the vertical direction shown in Fig. 1 , and is rotatable about its direction of extension.
• the high-speed rotational driving action of the motor 3 is outputted to the main shaft 5 after undergoing direction change and speed reduction via the rotating shaft 2 and the gear mechanism.
• a grinding disc 20 formed as a round plate may be mounted on the main shaft 5 as a top end tool (rotating tool), for use in grinding application, etc. to level the surface of concrete or stone, metal, and other unhazardous materials which can be ground or cut.
• the mounted top end tool is not limited to an abrasive disc or a diamond disc for grinding in the form of a round plate; it is also possible to mount an abrasive disc or a diamond disc for cutting, a cutter or a brush in the form of a round plate, etc.
• a circuit board 10 is mounted in the tool housing 21 and is located adjacent to motor housing 4.
• the wiring between the circuit board 10 and the motor 3 will be very short, greatly reducing the complexity of arrangement of the wires.
• the wiring is a source of heat inside the tool, so shortened wiring will also help to reduce losses and the amount of heat generated by the electric tool during operation.
• the motor 3 may be fitted to a complete circuit in advance - this is an electrically complete unit, which is easy to handle.
• the circuit board 10 is located parallel to the rotating shaft 2 of the motor. More preferably, the circuit board 10 is located above the motor housing 4.
• the wires connecting the motor and the circuit board would be shortest and the cooling path would be optimized.
• the electric tool 1 further comprises a battery accommodating part 8, which is mounted behind the motor housing 4 and used to accommodate a rechargeable battery 7.
• the battery accommodating part 8 and the motor housing 4 are separate components, i.e. the battery accommodating part 8 and the motor housing 4 are not integrally formed.
• the battery accommodating part 8 is composed of a left housing and a right housing, which are fixedly connected to left and right sides of the motor housing 4 respectively, for example by screws.
• the left and right housing are substantially in the form of two symmetrical [ shapes, fitted together to form a substantially square cavity 15 having an opening that is open in an upward direction.
• the bottom of the cavity 15 may be closed, semi-closed, or open.
• a front side of the battery accommodating part 8 close to the motor housing 4 is provided with a battery mounting part 14, and the battery 7 is removably attached to the battery mounting part 14.
• the battery mounting part 14 is close to a side of the motor housing 4 so that the wires connecting the battery 7 and the circuit board 10 are shorter, helping to simplify the layout of wires and avoid generating heat.
• the battery mounting part 10 provided at the front side of the battery accommodating part 8 is substantially in the form of a flat plate which is rectangular and projects mainly towards the rear. As shown in Figs. 3 and 4 , two mounting guide grooves are provided on a rear surface of the battery mounting part 10, the two battery mounting guide grooves being configured in a left/right arrangement.
• the battery 7 is a lithium ion battery with multiple cells accommodated in a hexahedral case.
• One of the longitudinal faces of the battery 7 extending along its length is a mounting face thereof, and two mounting guide rails are provided on the mounting face, such that the battery 7 is removably mounted to the battery mounting part 14 by sliding.
• the battery accommodating part 8 is substantially in the form of a cavity 15 having an opening that is open in an upward direction; the battery has only one longitudinal mounting face of the hexahedron connected inside the cavity 15, while a longitudinal face opposite the mounting face faces towards a rear sidewall of the cavity, with a gap between itself and the rear sidewall.
• Left and right sides of the cavity 15 respectively comprise battery protection parts 16 extending substantially along the longitudinal length of the battery.
• the battery protection part 16 comprises an upper part and a lower part, which respectively cover parts of the battery 7 which extend vertically beyond the motor housing 4 when the battery is mounted in the battery accommodating part 8.
• a heavy-duty angle grinder according to a schematic embodiment of the present invention often needs to be paired with a high-powered rechargeable battery; the battery 7 has a large size, with at least the longitudinal length thereof being larger than the size of a commonly used motor.
• the battery protection parts 16 are provided at the left and right sides of the battery accommodating part 8; this not only guarantees convenience of mounting and removal of the battery, but also ensures that the battery will not be damaged easily after being mounted to the electric tool, even if the electric tool 1 is accidentally dropped or knocked.
• the battery 7 comprises an unlock button 17, for releasing the battery 8 from the battery mounting part 14.
• the unlock button 17 is arranged on the longitudinal mounting face of the battery 7, and the position thereof is higher than the motor housing 4 when the battery 7 is mounted to the battery accommodating part 8. By sliding the battery 7 upwards in a state of having performed a pressing operation on the unlock button 17, the battery 7 can be removed from the battery mounting part 14. The battery 7 can be charged for repeated use by using a separately prepared charger.
• the mounting direction of the battery 7 is substantially perpendicular to the direction of extension of the rotating shaft, thus helping to balance the centre of gravity of the electric tool, and making the battery exchange most convenient. More preferably, when the battery 7 is mounted to the battery accommodating part 8, the longitudinal direction thereof is substantially parallel to the direction of extension of the main shaft. During use of the electric tool 1, there is little interference with battery. Especially during cutting, it is undesirable for the battery accommodating part to strike the ground, and if the battery is arranged obliquely, a bottom end thereof will contact the ground to an even greater extent. In addition, when the battery is mounted parallel to the direction of extension of the main shaft, insertion and withdrawal are easier in this direction.
• At least one air inlet 11 is formed on the tool housing 21 above the circuit board 10.
• a front end of the motor 3 is provided with a fan 12, and at least one air outlet 13 is formed on the gearbox in front of the fan 12.
• the fan 12 forms negative pressure, so external air is sucked in via the air inlet 11.
• the air inlet 11 is arranged above the circuit board, so external air flows past the circuit board along the most direct path, ensuring cooling of electronic devices on the circuit board to the maximum extent possible. As shown in Fig.
• a handle 9 is mounted behind the battery accommodating part 8.
• the battery 7 is mounted between the motor 3 and the handle 9, thus optimizing the balance of the overall structure of the electric tool, and avoiding interference between a user's hand and the battery, so the electric tool has better ergonomics.
• the handle 9 is also mounted and connected to the battery accommodating part; thus, the handle, the battery accommodating part and the drive unit are all independent components, not integrally formed. The process of manufacturing and shaping the electric tool becomes simple and easy to implement.
• the motor housing is a single-piece cylinder, and it is not advisable for the motor housing to be split in the middle; therefore, the motor housing must be released from its mould in the length direction thereof. If the battery accommodating part and the handle were integrally formed with the motor housing, it would be very complicated to release the battery accommodating part from its mould in the same direction. Furthermore, the work of mounting the wiring and the battery mounting part would also become complex, and the ability to overhaul the battery accommodating part would be lost.
• the handle 9 is substantially in the form of a D shape extending in the front-rear direction.
• the D-shaped handle helps the user to grip the tool conveniently and reliably, and also helps to balance the overall structure of the electric tool.
• the handle is rotatable.
• a front end of the handle is connected to the rear of the battery accommodating part 8 via a rotation mechanism 18.
• the electric tool is also used for cutting applications in which a peripheral surface region of an abrasive or diamond disc is used to cut a material being processed, and the rotatable handle helps the user to grip the tool better in various application scenarios.
• the handle 9 rotates about a rotation axis X parallel to the direction of extension of the rotating shaft.
• the rotation mechanism 18 has a locking part 19 for locking a rotation angle
• the handle 9 has at least three locking positions at - 90 degrees, 0 degrees and 90 degrees relative to the rotation axis X thereof.
• the handle of the electric tool of the present invention can rotate through 90 degrees, so is conveniently suitable for grinding applications or cutting applications.
• the handle 9 can rotate 90 degrees to the left or right separately about the rotation axis X, so is more friendly to users accustomed to operating electric tools with the left hand. It is also extremely important that the handle can be kept in a locked state after rotating to the desired angle, to ensure that undesired rotation or shifting of the electric tool will not occur during operation.
• the present invention is not limited to an angle grinder, and may be applied to various electric tools having a main output shaft intersecting the direction of extension of a tool main body, especially grinding tools that grind a workpiece by making a top end tool rotate, e.g. a polisher, etc.
• other structures of angle grinders are not limited to the arrangement described above.
• the motor is not limited to a brushless motor.
• multiple battery packs (batteries) may also be used as a power supply.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

Priority Applications (2)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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Citations (9)

• 2024
  • 2024-03-18 EP EP24164141.4A patent/EP4620623A1/fr active Pending
• 2025
  • 2025-03-05 WO PCT/EP2025/055943 patent/WO2025195773A1/fr active Pending

Patent Citations (9)

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