Impact wrench

Abstract

An impact wrench (1) comprising: a motor unit (3) having a motor (3') adapted to generate a rotational movement and an operating switch (5) for operating the motor (3'); a tool holder shaft (2) rotatable about a rotational axis (R); a transmission unit (6) having a percussion mechanism (7) connected between the motor unit (3) and the tool holder shaft (2); a handle bar structure (14) having two gripping handles (9, 10) for manually gripping the wrench (1); an electronic control system (27) comprising at least one electronic control board connected to one or more electric batteries (4) and to the operating switch (5), wherein the electric motor (3') is powered simultaneously by two rechargeable batteries (4) connected in parallel to each other and housed together in a main housing (15), wherein the electronic control system (27) comprises means for generating an electric current supplied to the motor (3') configured to generate a first phase of a three-phase electric current with a first one (4') of the batteries (4), a second phase of the three-phase electric current with a second one (4") of the batteries (4) and a third phase of the three-phase electric current with the first and second batteries (4', 4"), wherein the ratio of the contribution of the first (4') and second (4") batteries to the generation of the third phase is determined in dependence on the residual charge state of the batteries (4', 4"), wherein the least charged battery (4', 4") contributes less to the generation of the third phase than the most charged battery (4", 4').

Description

Technical Field

[0001] This invention relates to a portable impact wrench or nut tightener with an electric motor and a battery, particularly for tightening and loosening bolts, nuts and rail screws on rails and sleepers in the construction and maintenance of railway lines, and for assembling truck wheels. Background Technology

[0002] There are two main identifiable applications in railway construction:

[0003] - The tracks are joined together by means of perforated plates arranged on both sides of the perforated rods of two adjacent tracks and tightened by means of horizontal bolts, thereby forming a continuous iron surface.

[0004] - The rail connectors are anchored to the sleepers using vertical screws. This application requires tightening or loosening vertically from the top.

[0005] The assembly or removal of truck wheels involves tightening or loosening the wheel's retaining nuts in a horizontal position.

[0006] The jobs listed above are physically demanding, repetitive, and require various postures, which can quickly lead to muscle fatigue in workers. Tightening and loosening operations generate considerable acoustic noise and mechanical vibration due to the interaction of impact mechanisms, internal combustion engines, reduction gears, and the friction between bolts, nuts, and screws and the parts to be tightened or loosened. Furthermore, using wrenches under varying climatic conditions, directly on the ballast of railway lines, sometimes placed directly on it, and sometimes in a vertical position, exposes the wrenches not only to intense mechanical stress but also to the inevitable moisture, water droplets and mist, stones, and metal dust present on railway sleepers.

[0007] Noise and vibration, along with the weight of the wrench and the exhaust fumes from the internal combustion engine, create conditions of wear and tear for workers.

[0008] In addition, mechanical vibration and exposure to dust and moisture can cause degradation of the mechanical and electrical / electronic parts of a wrench.

[0009] The heat generated by a wrench motor must be limited by forced ventilation to prevent overheating of the motor and electrical / electronic components and to protect the operator. This requirement applies to both internal combustion engines and electric motors. However, forced ventilation can draw dust, moisture, and water droplets into the wrench housing, increasing the risk of damage to electrical and electronic components.

[0010] Finally, the vibration of the motor, reducer, and impact mechanism moves and wears down the parallel interface of the wrench housing, further promoting the entry of moisture, water droplets, and dust into the wrench. Summary of the Invention

[0011] Therefore, the object of the present invention is to provide an improved impact motorized wrench that has features that overcome at least some of the disadvantages mentioned in the prior art. Attached Figure Description

[0012] To better understand the present invention and its advantages, some non-limiting examples of embodiments will be described below with reference to the accompanying drawings, in which:

[0013] Figure 1 and Figure 2 This is a perspective view of a power wrench according to an embodiment of the present invention;

[0014] Figure 3 yes Figure 1 A top view of a power wrench;

[0015] Figure 4 yes Figure 1 A bottom view of a power wrench;

[0016] Figure 5 yes Figure 1 A side view of the motorized wrench in the picture;

[0017] Figure 6 It is along Figure 5 A partial cross-sectional view taken from plane VI-VI in the section;

[0018] Figure 7 It is along Figure 3 A partial cross-sectional view taken from section plane VII-VII in the diagram;

[0019] Figure 8 and Figure 9 yes Figure 1 The exploded rear side perspective and front side perspective of the motorized wrench in the picture;

[0020] Figure 10 This is an exploded perspective view showing details of the vibration damping connection of a power wrench according to one embodiment;

[0021] Figure 11 This is a detailed view of the housing of a power wrench according to one embodiment, showing the separation between the power battery compartment and the motor compartment by means of a radiator wall (heat sink);

[0022] Figure 12 Details of the motor compartment of the housing of a power wrench according to one embodiment are shown;

[0023] Figure 13 This is an exploded perspective view of the housing of a power wrench according to one embodiment, showing a single housing shell, the connection interface of the single housing shell, and a sealing gasket. Detailed Implementation

[0024] Description of the power wrench 1

[0025] Referring to the accompanying drawings, the power wrench (hereinafter referred to as a wrench) is generally indicated by reference numeral 1 and includes a tool retainer shaft 2 adapted to engage a bushing or similar tool supporting the head of a screw or nut to be tightened or loosened. The tool retainer shaft 2 is arranged on the front side F of the wrench 1 and is rotatably supported about the axis of rotation R.

[0026] A motor unit 3, powered by one or more, preferably two, rechargeable batteries 4, such as an electric motor 3', preferably a brushless motor, can be arranged in the central area of ​​the wrench 1 or on the rear side P of the wrench opposite to the front side F, and is adapted to generate kinetic energy, particularly the torque and rotational motion required for tightening / loosening operations. The motor unit 3 can be operated and controlled by means of a manual actuation member (e.g., a button or trigger switch 5).

[0027] The wrench 1 further includes a transmission unit 6 having an impact mechanism 7 disposed between the motor unit 3 and the tool holder shaft 2. This transmission unit 6 (e.g., a reducer mechanism) interacts with the motor 3' and the tool holder shaft 2 to transmit rotational motion (converting its angular velocity and torque) from the motor 3' to the tool holder shaft 2 for rotating the latter about the axis of rotation R.

[0028] The motor unit assembly 3, the transmission unit 6, and the impact mechanism 7 form the base 8 of the wrench 1, which extends substantially along the axis of rotation R.

[0029] The wrench 1 further includes two gripping handles 9, 10 fixed to the base 8. The gripping handles 9, 10 are both elongated and laterally spaced from each other relative to their longitudinal extensions; in other words, they are not arranged along a straight line. Advantageously, the two gripping handles 9, 10 are oriented to define a gripping plane A, which is substantially tangential to the two gripping handles 9, 10 and transverse to, and preferably perpendicular to, the axis of rotation R. The actuating member 5 of the motor 3' can be associated with one of the two gripping handles 9, 10.

[0030] The wrench 1 may further include an elongated auxiliary handle 11 arranged on the upper side S of the wrench 1 and spaced apart from the gripping plane A along the axis of rotation R in the direction of the front side F of the wrench 1, and may extend parallel to the axis of rotation R.

[0031] Two grip handles 9, 10 and an auxiliary handle 11 (if provided) can together form a three-dimensional handle bar structure 14, which is preferably connected and rigid and connected to the base 8 of the wrench 1, for example by means of a screw and by means of an interposing damping element, such as a bushing or rubber pad (so-called anti-vibration element).

[0032] Description of vibration damping system 12

[0033] According to one aspect of the invention, the wrench 1 includes a damping connection system 12 (in other words, an anti-vibration system) that mechanically connects the transmission housing 13 of the transmission unit 6 (reducer and impact mechanism) to the main housing 15 of the motor unit 3 (either an electric motor 3' or with one or more batteries 4) and the main housing 15 to the handle lever structure 14. The damping connection system includes one or more first damping elements 16, such as bushings or rubber pads, between the transmission housing 13 and the main housing 15, and one or more second damping elements 17, such as bushings or rubber pads, between the main housing 15 and the handle lever structure 14, such that:

[0034] The vibration transmitted from the transmission housing 13 to the main housing 15 is damped by the first damper element 16.

[0035] The vibration transmitted from the transmission housing 13 to the handle rod structure 14 is damped sequentially by the first damper element 16 and the second damper element 17.

[0036] Vibrations transmitted from the main housing 15 to the handle rod structure 14 are damped by the second damper element 16.

[0037] Furthermore, the wrench 1 has no rigid mechanical connection that bypasses the first damper element 16 and the second damper element 17 between the transmission housing 13, the main housing 15 and the handle rod structure 14.

[0038] The damping connection system 12 implements two anti-vibration barriers in series between the transmission housing 13 (where the reducer and the hammer of the impact mechanism 7 generate the main mechanical vibrations and impacts) and the handle bar structure 14 gripped by the user, thereby protecting the user from harmful vibrations and allowing for extended use time of the wrench 1.

[0039] In addition, the damping connection system 12 utilizes one of the two vibration barriers as a vibration barrier between the transmission housing 13 and the main housing 15 to protect the motor 3', control electronics and power components, as well as the connection interface of the individual housing, possible display components, etc., from damage caused by undesirable mechanical movement, impact and wear.

[0040] According to one embodiment, the damping connection system 12 includes a central connection body 18, such as a plate or rigid frame. Figure 6 , Figure 10 Preferably made of metal (aluminum or steel), it is positioned between the motor unit 3 and the transmission unit 6, and its structure is as follows:

[0041] - An opening or channel cavity 19 for the passage of the transmission component (crankshaft or drive shaft) 20 between the motor 3' and the transmission unit 6.

[0042] - A plurality of first connecting seats 21 (preferably having connecting holes for damping seats) for connecting the central connecting body 18 to the transmission housing 13 by means of an intervening first damper element 16, for example by means of screws.

[0043] - A plurality of first connecting seats 22 (preferably with connecting holes for damping seats) for connecting the central connecting body 18 to the handle rod structure 14 by means of an intervening first damper element 17, for example by means of screws, and possibly

[0044] - Multiple third connectors 23 (preferably connector holes) for connecting the central connector body 18 to the main housing 15, for example by means of screws.

[0045] As an alternative to the third connector 23, the central connector 18 can be integrally formed with the main housing 15.

[0046] According to one embodiment, each of the first connecting seats 21 includes a hole for inserting a screw or connecting pin and a corresponding cylindrical seat or flange for at least partially receiving one of the first damper elements 16.

[0047] Advantageously, three or more, preferably four, first connecting seats 21 are provided around the rotation axis R and positioned at a certain distance from the rotation axis.

[0048] According to one embodiment, each of the second connecting seats 21 includes a hole for inserting a screw or connecting pin and a corresponding cylindrical seat or flange for at least partially receiving one of the second damper elements 17.

[0049] Advantageously, three or more, preferably four, second connecting seats 22 are provided around the rotation axis R and positioned at a certain distance from the rotation axis.

[0050] The second connecting seat 22 is made at a distance from each other and from the first connecting seat. Advantageously, the orientation of the second connecting seat 22 (e.g., the screw / pin insertion axis) is transverse to, and preferably perpendicular to, the orientation of the first connecting seat 21. For example, the first connecting seat 21 may be oriented parallel to the axis of rotation R, while the second connecting seat may be oriented perpendicular to the axis of rotation R. Figure 10 ).

[0051] According to another embodiment, the orientation of the second connector (22) is parallel to the orientation of the first connector (21), for example, parallel to the axis of rotation (R). Alternatively, the first connector (21) and / or the second connector (22) may be oriented perpendicular to the axis of rotation (R).

[0052] According to one embodiment, each of the third connectors 23 includes a hole for inserting a screw or connecting pin, and preferably, they are oriented parallel to the axis of rotation R.

[0053] The central connecting body 18 may include reinforcing ribs 24 and lightening openings 25.

[0054] According to another embodiment, the damping connection system 12 includes one or more third damping elements 55 (e.g., bushings or rubber gaskets) positioned between the central connection body 18 and the main housing 15, such that:

[0055] Vibrations transmitted from the central connecting body 18 to the main housing 15 are damped by the third damper element 55.

[0056] The vibration transmitted from the transmission housing 13 to the main housing 15 is damped sequentially by the first damper element 16 and the third damper element 55.

[0057] - The vibration transmitted from the main housing 15 to the handle rod structure 14 is damped sequentially by the third damper element 55 and the second damper element 16.

[0058] According to one embodiment, each of the third connecting seats 23 of the central connecting body 18 includes a hole for inserting a screw or connecting pin and a corresponding cylindrical seat or flange for at least partially receiving one of the third damper elements 55.

[0059] According to one embodiment, the wrench 1 includes a vibration sensor 26, such as an accelerometer, which is placed and configured to detect vibrations of the handle lever structure 14 and is signal-connected to the electronic control system 27 of the wrench 1.

[0060] Preferably, the vibration sensor 26 is positioned at one of the grip handles 9 and 10.

[0061] The electronic control system 27 is configured to generate a notification (e.g., a symbol, color, alphanumeric, sound or number, remaining usage time or permitted excessive usage time) based on the detected vibration value, the operating time involved in the detected vibration value, and a predetermined exposure limit.

[0062] For example, the electronic control system 27 is configured to:

[0063] - The vibration value detected by vibration sensor 26 is correlated with the operating time of wrench 1, that is, correlated with the duration of the detected vibration, and

[0064] - Compare the detected vibration values ​​and the duration of the detected vibrations with the predetermined and indicative vibration values ​​and / or reference times for the permissible exposure interval (e.g., as specified in occupational safety regulations).

[0065] According to one embodiment, the electronic control system 27:

[0066] – Calculate the intensity (or modulus) of the acceleration vector based on the acceleration vector components detected by the vibration sensor 26.

[0067] – Calculate the average or root mean square value of the acceleration vector modulus.

[0068] - Compare the average or root mean square value and duration of the detected vibrations with the associated values ​​of the indicative and predetermined reference time of the permissible exposure interval and the reference vibration values ​​(e.g., as required by occupational safety regulations).

[0069] Preferably, the electronic control system 27 filters the detected vibration values ​​by excluding vibrations at frequencies above a predetermined threshold that are harmless to the user from the processing.

[0070] According to another embodiment, the electronic control system 27 compares the characteristics of the detected vibration (frequency and / or intensity of acceleration) with a predetermined reference interval indicating the correct operation of the wrench 1, and generates a fault warning if the characteristics of the detected vibration deviate from the predetermined reference interval.

[0071] Advantageously, the comparison takes into account (e.g., by means of using different predetermined reference intervals on which it is based) the level of torque set by the user (e.g., by means of the torque selection switch 51, which will be described later).

[0072] Detailed description of the ventilation system and seals

[0073] The screw driver 1 includes a cooling fan 30 for the motor 3', which is configured to be activated together with the operation of the motor 3', to draw in ambient air through an inlet opening (grid) 28 formed in the main housing 15, to deliver the drawn ambient air through or along the motor 3', and to exhaust the air to the environment through an outlet opening (grid) 29.

[0074] Advantageously, the cooling fan 30 is directly connected to the rotor of the motor 3' on the side facing the rear P of the wrench 1.

[0075] Preferably, the inlet opening (grid) 28 is located on two opposite lateral sides of the main housing 15 and may include an inlet guide surface 31 that guides the intake airflow inside the main housing 15 toward the rear side P of the wrench 1 and toward the partition wall (34).

[0076] Preferably, the outlet opening (grid) 29 is located on the front side of the main housing 15 facing the front side F of the wrench 1 and may have, for example, an annular slit shape through which the cooling airflow is discharged in the forward axial direction. In this way, the discharged airflow removes dust or scraped chips that are dispersed during tightening / loosening from the main housing (15).

[0077] According to one aspect of the invention, the motor 3' is housed inside a dedicated motor compartment 32 of the main housing 15, and at least one thermal component (in particular the electronic control board) or substantially the entire electronic control system 27 may be housed together with one or more power batteries 4 inside a protected compartment 33.

[0078] The protected compartment 33 is directly adjacent to, but not connected to, the motor compartment 32, and is separated from it by a partition wall 34. The cooling fan 30 delivers cooling airflow along the partition wall 34 only to the motor compartment 32, which forms a metal radiator (heat sink) 35. This metal radiator exchanges heat with the heat-sensitive components of the electronic control system 27, particularly with the electronic control board in the protected compartment 33. Figure 9 , Figures 11-13 ).

[0079] In this way, the motor 3' and heat-sensitive electrical and electronic components can be cooled without allowing dust, moisture, and possible water droplets carried by the cooling airflow to come into contact with the electrical and electronic components of the electronic control system 27. This ensures an improved level of water resistance and reliable use of the wrench 1 in adverse weather conditions and in the presence of dust.

[0080] Advantageously, the protected compartment 33 houses the electronic board of the control system 27 and one or more batteries 4 for supplying power therein.

[0081] According to one embodiment, the metal radiator 35 forms a plurality of cooling fins 36 that protrude into the motor compartment 32 and are in direct contact with the cooling airflow.

[0082] According to another embodiment, the metal radiator 35 forms a plate-like protrusion 37 that extends into the protected compartment 33 and is in direct contact with the electronic board of the control system 27.

[0083] According to another embodiment, the main housing 15 forms the motor compartment 32 and the protected compartment 33 and includes:

[0084] - Two opposing side shells 38, 38', made of, for example, plastic, are arranged side by side along the first contact interface 39, preferably in a plane parallel to the axis of rotation R, and together define a protected compartment 33, a rear opening 40 for access to the protected compartment 33 that can be closed by means of a rear cover 41, preferably an elastomer, and a partition wall 34 having a heat sink base 42 for accommodating a metal radiator 35.

[0085] - The front housing 43, preferably made of plastic, is positioned along the second contact interface 44, preferably in a plane orthogonal to the axis of rotation R, near the side housings 38, 38', and together with the side housings 38, 38', defines the motor compartment 32 and a control base 45, possibly for accommodating the user control panel 46.

[0086] The first washer 47, preferably made as a single piece, extends along the first contact interface 39 and along the radiator seat 42 (and around the metal radiator 35 housed therein).

[0087] The second washer 54, preferably made as a single piece, may extend along the control seat 45 or at the control panel 46 in which it is housed.

[0088] Another washer may extend along the second contact interface 44, but this additional washer is not necessary because the motor compartment 32 remains in communication with the external environment.

[0089] In this way, a higher level of protection from dust, moisture and water droplets is achieved, and the first contact surface 39 is locally damped and protected from the harmful effects of mechanical vibration.

[0090] Advantageously, the rear cover 41 is made of an elastic material or has elastic edges so that it can be elastically fitted onto the protruding edge of the rear access opening 40.

[0091] The rear cover 41 can be non-removably hinged to the main housing 15.

[0092] Description of power supply using two batteries 4

[0093] According to another aspect of the invention, the electric motor 3' (e.g., a synchronous brushless motor with a permanent magnet and an integrated control unit and a battery-powered 36-volt DC power supply) is powered by two rechargeable batteries 4, which are preferably connected in parallel with each other, such as lithium-ion batteries with a voltage of 36V, 8Ah or higher, which are housed together in a protected compartment 33 of the main housing 15.

[0094] The electronic control system 27 includes a device (e.g., using a MOSFET (metal-oxide-semiconductor field-effect transistor)) for generating current supplied to the motor 3'. This device is configured to generate a first phase of the three-phase current using a first cell of the battery 4, a second phase of the three-phase current using a second cell of the battery 4, and a third phase of the three-phase current using both cells 4. The ratio of the contribution of the first and second cells to the generation of the third phase is determined based on the remaining charge state of the batteries 4. Specifically, the battery with the least charge contributes less to the generation of the third phase than the battery with the most charge.

[0095] The current supplied to the electric motor 3' is greater than the current supplied by only one of the two batteries 4.

[0096] In addition to the main power supply contact 48, the battery 4 also includes auxiliary contacts for controlling battery operating conditions. The electronic control system 27 identifies the type of battery used by detecting the resistance between the auxiliary contacts.

[0097] The wrench 1 further includes a display 50, which can form part of the user control panel 46 for displaying the charging status of the battery 4. To prevent damage (stall) to the motor 3' due to an excessively low supply voltage, the control system 27 is configured to detect a low battery state, for example by detecting a low battery signal at the auxiliary contact 49, or by detecting the voltage of the battery 4 and comparing the detected voltage with a predetermined minimum threshold (depending on the type of battery used).

[0098] When the control system 27 determines that the battery is low, its control wrench 1 completes any ongoing turning cycle and prevents further operation, or prevents any further operation until sufficient voltage is established (after replacing battery 4 or recharging the battery).

[0099] Description of Wrench 1 - User Interaction

[0100] According to one embodiment, the wrench 1 (preferably formed in a user control panel 46 on the main housing 15) includes an electrically operated torque selection switch 51 connected to a control system 27, allowing selection of multiple, for example, five torque values ​​or levels within the range of torque that the wrench 1 can transmit. For example, the maximum transmittable torque could be equal to 2700 Nm. The control system 27 controls the rotational speed of the motor 3' based on the selected torque level or value. The rotational speed of the motor 3' determines the rotational impact intensity of the impact mechanism 7, and thus determines the transmittable torque.

[0101] The torque selection switch 51 may include a rotary switch, possibly with a Hall sensor and a digital code for the angle selection position.

[0102] The wrench 1 (preferably the user control panel 46) further includes a main switch 52 (e.g., an unstable balancer) which is connected to the control system 27 and is used to turn the control system on and off.

[0103] The wrench 1 further includes a direction selection switch 53 (e.g., a switch with a stable slide) having two positions, connected to the control system 27, for selecting the direction of rotation of the motor 3' for tightening and loosening. Advantageously, the direction selection switch 53 is positioned at one of the grip handles 9, 10.

[0104] The wrench 1 further includes an operating switch 5, such as an unstable switch with a button or trigger, which is connected to the control system 27 for activating the rotation of the motor 3'. Advantageously, the operating switch 5 is located at the same gripping handle 9, 10 connected to the direction selection switch 53.

[0105] To minimize the risk of accidents, the electronic control system 27 is configured to automatically brake the motor 3' when the operating switch 5 is released, for example by means of electromagnetic braking.

[0106] Wrench 1 is suitable for tightening and loosening nuts / screws of different sizes on railway sleepers made of different materials (wood, cement, plastic) and metal plates used to connect rails. It is also suitable for assembling / disassembling truck wheels, the oil and mining industry, construction and forestry engineering, and various types of emergency interventions.

Claims

1. An impact wrench (1), comprising: The motor unit (3) has a motor (3') housed in the main housing (15) of the wrench (1) and adapted to generate rotational motion, and an operating switch (5) for operating the motor (3'). The tool retainer shaft (2) is rotatable about the rotation axis (R). The transmission unit (6) has an impact mechanism (7) connected between the motor unit (3) and the tool holder shaft (2). An electronic control system (27) comprising at least one electronic control board connected to one or more power batteries and connected to the operating switch (5). The handle rod structure (14) has two grip handles (9, 10) for manually gripping the wrench (1). The transmission unit (6) interacts with the motor (3') and the tool holder shaft (2) to transmit the rotational motion from the motor (3') to the tool holder shaft (2) for rotating the tool holder shaft (2) about the rotation axis (R). The electric motor (3') is powered by two rechargeable batteries connected in parallel and housed together in the main housing (15). The electronic control system (27) includes means for generating current supplied to the motor (3'), the means being configured to use a first battery (4') in the battery to generate a first phase of the three-phase current, use a second battery (4") in the battery to generate a second phase of the three-phase current, and use the first battery (4') and the second battery (4") to generate a third phase of the three-phase current. The ratio of the contribution of the first battery (4') and the second battery (4") to the generation of the third phase is determined based on the residual charge state of the batteries. Among them, the battery with the least charge contributes less to the generation of the third phase than the battery with the most charge.

2. The wrench (1) according to claim 1, wherein, The current supplied to the electric motor (3') is greater than the current that can be supplied by only one of the two first batteries (4') and the second battery (4").

3. The wrench (1) according to claim 1 or 2, comprising a display (50) for displaying the charge status of the battery.

4. The wrench (1) according to claim 1, wherein, The control system (27) is configured to: The low battery state is detected by detecting a low battery signal at the auxiliary contact (49) of the battery or by detecting the voltage of the battery. The detected voltage is compared with a predetermined minimum threshold based on the battery type. When a "low battery" state is determined, check the motor (3') to end any ongoing twisting cycle and prohibit subsequent operations, or prohibit any further operations until sufficient voltage is determined.

5. The wrench (1) according to claim 1, comprising: An electric torque selection switch (51), connected to the control system (27) of the wrench (1), allows selection of multiple levels of transmittable torque. The control system (27) controls the rotational speed of the motor (3') according to the selected torque level. A main switch (52), which is connected to the control system (27) and used to turn the control system on and off, A direction selection switch (53), connected to the control system (27), is used to select the rotation direction of the motor (3'), and the direction selection switch (53) is located at one of the grip handles (9, 10). An operation switch (5), which is connected to the control system (27), is used to activate the rotation of the motor (3'), and the operation switch (5) is placed on the same grip handle (9, 10) connected to the direction selection switch (53).

6. The wrench (1) according to claim 1, wherein, The electronic control system (27) is configured to automatically brake the motor (3') when the operating switch (5) is released.

7. The wrench (1) according to claim 3, comprising: The cooling fan (30) of the motor (3') is configured to be activated together with the operation of the motor (3') for drawing in ambient air through an air inlet opening (28) formed in the main housing (15), conveying the drawn-in air along the motor (3'), and discharging the conveyed air through an air outlet opening (29) formed in the main housing (15). in: The motor (3') is housed inside a dedicated motor compartment (32) of the main housing (15), and at least one thermal component of an electronic control system (27) containing at least one electronic control board is housed inside a protected compartment (33) of the main housing (15). The protected compartment (33) is directly adjacent to the motor compartment (32) and separated from it by a partition wall (34), and the cooling fan (30) also delivers cooling airflow along the partition wall (34) only to the motor compartment (32). The partition wall (34) includes a metal radiator (35) that faces directly into the motor compartment (32) and exchanges heat with the heat-sensitive components of the electronic control system (27) in the protected compartment (33).

8. The wrench (1) according to claim 1, comprising: A damping connection system (12) mechanically connects the transmission housing (13) of the transmission unit (6) to the main housing (15) of the motor unit (3) and mechanically connects the main housing (15) to the handle rod structure (14), and the damping connection system includes: One or more first damper elements (16) are located between the transmission housing (13) and the main housing (15), and One or more second damper elements (17), which are located between the main housing (15) and the handle rod structure (14), such that: The vibration transmitted from the transmission housing (13) to the main housing (15) is damped by the first damper element (16). The vibration transmitted from the transmission housing (13) to the handle rod structure (14) is damped sequentially by the first damper element (16) and the second damper element (17). Vibrations transmitted from the main housing (15) to the handle rod structure (14) are damped by the second damper element (17).

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