Cutting tool drive for lawnmowers

Abstract

Cutting tool drive (3) for a lawn cutting tool (2) of a lawn mower (1), wherein the cutting tool drive (3) comprises a clutch, characterized in that the clutch is designed as an electrically actuated magnetic clutch (20) and the cutting tool drive (3) comprises a thermal protection device (40) which cancels the electrical actuation of the magnetic clutch when an overheating condition occurs.

Description

[0001] In practice, it is common to operate the turf-cutting attachment of a lawnmower via a motor drive. The motor drive is usually connected to the turf-cutting attachment via a gearbox, and may be activated by a clutch.

[0002] It has been shown that parasitic influences on the lawn aerator can cause significant slippage in the power transmission between the motor and the aerator. This slippage can lead to malfunctions in the clutch and / or gearbox. For example, cutting tall and / or damp grass too quickly, possibly in combination with a clogged or overloaded grass catcher, can cause the aerator to lock up completely or its operating speed to be drastically reduced. In a worst-case scenario, the clutch can become locked, either permanently open or permanently closed, and lose its ability to engage. This can damage other components, including overloading or destroying the motor, which can lead to further risks.

[0003] The object of the present invention is to demonstrate an improved drive technology for a lawn mower's turf-cutting tool. The invention achieves this object through the features of the independent claims.

[0004] The disclosed drive technology can include a cutting tool drive for a lawn cutting tool of a lawnmower, a lawnmower equipped with the cutting tool drive, and a magnetic coupling connection cable.

[0005] The disclosed drive technology offers or supports various advantages. Excessive slippage and the resulting overheating of the coupling can be detected, and the torque transmission can be interrupted in such a case, thus preventing (further) damage to the coupling or impairment of the motor drive. The coupling can be retrofitted to an existing system to implement the disclosed drive technology by adding a connecting cable. The coupling can function as an electrically actuated magnetic coupling with fully automatic overheating detection. If an overheating condition is resolved, a reset (manual and / or automatic) may be possible to return the cutting tool drive to normal operation.

[0006] A cutting tool drive according to the present disclosure is designed and configured for a lawn mower's cutting tool. The cutting tool drive includes a clutch designed as an electrically actuated magnetic clutch. It further includes a thermal protection device that, in the event of overheating, disables the electrical actuation of the magnetic clutch. Disabling the electrical actuation preferably disconnects the torque-conducting effect of the cutting tool drive. In particular, a lawn cutting tool is decoupled from a motor drive. This can counteract the cause of an overheating condition. The lawn mower user will generally detect the interruption and be alerted to a fault condition either by this or by an additional warning indicator, which may preferably be triggered when the thermal protection device is activated.The user can then rectify any mechanical cause of the slippage in the cutting tool drive, for example by changing the cutting settings of the lawnmower and / or clearing the clippings collection area.

[0007] A magnetic clutch connection cable according to the present disclosure is designed and configured for supplying electrical power to a magnetic clutch of a cutting tool drive for a lawnmower. The magnetic clutch connection cable may include a thermal protection device which, in the event of overheating, disables the electrical actuation of the magnetic clutch.

[0008] The magnetic coupling connection cable can be used for one or, preferably, several types of magnetic couplings. It can therefore support a modular retrofit of an existing cutting tool drive.

[0009] Further advantageous embodiments of the disclosure are specified in the dependent claims and the following drawing description.

[0010] The invention is illustrated in the drawings in an exemplary and schematic manner. These show: Fig. 1: a lawnmower with a lawn cutting attachment; Fig. 2: a cutting tool drive according to the present disclosure in an exemplary embodiment; Fig. 3 and Fig. 4: a magnetic coupling with thermal protection in a first embodiment in an overview view as well as a detailed view of an electrical connection; Fig. 5 and Fig. 6: Representations analogous to Fig. 3 and Fig. 4 for a second version variant; Fig. 7 and Fig. 8: a third design variant; Fig. 9 and Fig. 10: a fourth variant; Fig. 11 and Fig. 12: a fifth variant.

[0011] Fig. Figure 1 shows a lawnmower 1 in an exemplary configuration. The lawnmower 1 can be of any design. For example, it can be a ride-on mower, a lawn tractor, or a walk-behind lawnmower. The lawnmower 1 can also be a robotic lawnmower or a multifunctional land vehicle with a flanged lawn-cutting tool. In the example of Fig. Figure 1 shows a ride-on mower.

[0012] Fig. Figure 2 illustrates a cutting tool drive 3 for a lawn cutting tool 2. The lawn cutting tool 2 is shown in the figures as an example of a permanent attachment of the lawnmower 1. Fig. Figure 1 shows the lawn cutting tool 2. It can have any configuration. In particular, it can have one, two, or more cutting units 6, 7. A cutting unit 6, 7 and / or the lawn cutting tool can be a permanent or temporary component of the cutting tool drive 3 or the lawnmower 1. It can be interchangeable with another component, such as a scarifying tool or other suitable soil cultivation tool.

[0013] The cutting tool drive 3 includes a coupling designed as an electrically actuated magnetic coupling 20.

[0014] The magnetic coupling 20 can switch or control torque transmission between a drive element 21 of the magnetic coupling and an output element 22 of the magnetic coupling. Preferably, the drive element 21 can be connected to, or be connected to, the motor drive 4 of a lawnmower 1 on the input side. Alternatively or additionally, the output element 22 can be connected to, or be connected to, the lawn cutting tool 2 or one of the aforementioned alternative soil cultivation tools on the output side.

[0015] The output connection can be direct or indirect, in particular via a gearbox. The gearbox can preferably be a component of the cutting tool drive 3 and / or a component of the lawn cutting tool 2. The gearbox can have any configuration. For example, the gearbox can comprise or be a gear drive. Alternatively or additionally, the gearbox can comprise or be formed by a circulating traction element. The circulating traction element can be, for example, a belt or a chain. In other words, the gearbox can comprise a chain drive and / or a belt drive. In the example shown, the gearbox is configured as a belt drive 5. The belt drive can be driven by a pulley on the output element 22 of the magnetic clutch 20 and, via optional belt deflections, connected to at least one pulley on a cutting unit 6, 7.The belt can transmit torque through friction, for example in the form of a V-belt. Alternatively, it can transmit torque through positive engagement, for example in the form of a toothed belt. In other words, a friction-based or positive-engaging belt drive 5 can be provided.

[0016] The magnetic coupling 20 can have any configuration and operating principle. According to a preferred embodiment, the magnetic coupling effects torque transmission when and / or as long as the electrical actuation of the magnetic coupling 20 is active. Alternatively or additionally, the magnetic coupling 20 can prevent torque transmission when and / or as long as the electrical actuation is inactive.

[0017] The magnetic clutch 20 preferably comprises a first clutch unit, in particular a first clutch disc, which is (non-rotatably) connected to the drive element 21, and a second clutch unit, in particular a second clutch disc, which is (non-rotatably) connected to the output element 22, in particular a pulley. Preferably, the clutch units, in particular clutch discs, can be brought into engagement with each other by electrical actuation. Alternatively, clutch claws can be provided instead of the clutch discs.

[0018] The overheating state can be defined arbitrarily. Preferably, it is an overheating state of the magnetic clutch. Alternatively or additionally, an overheating state of the gearbox can be detected, in particular an overheating state of a gearbox element that is connected to the magnetic clutch 20 on the output side, and further, in particular, an overheating state of the pulley.

[0019] Overheating can occur, in particular, when the temperature of the magnetic coupling, specifically a connection temperature, a housing temperature, or an output element temperature of the magnetic coupling, reaches or exceeds a predefined temperature limit. The following example assumes that the thermal protection reacts to an overheating condition of the magnetic coupling, which occurs, in particular, when the temperature of the magnetic coupling, specifically a connection temperature at an electrical terminal of the magnetic coupling, exceeds a predefined temperature limit.

[0020] The thermal protection device 40 preferably comprises a temperature-sensitive section 40a, which in particular detects when a predefined temperature limit is exceeded. The thermal protection device 40 may further comprise an electrically isolating section 40b, which allows the electrical actuation of the magnetic clutch to be deactivated. Furthermore, the thermal protection device 40 may optionally include a resetting section 40c, which allows the deactivation of the electrical actuation to be reversed, so that in particular the electrical actuation of the magnetic clutch can again take place in the usual manner via a power supply.

[0021] The power supply to the magnetic coupling (20) can be provided or configured in any way. Preferably, a load current can be transmitted via a first line (31) and a second line (32) of a connecting cable (30). The load current can be provided in any way and, in particular, can be an externally supplied power supply. When the load current is present, the power supply can be active. When the load current is switched off (by external means), the power supply can be interrupted.

[0022] A temperature-sensitive section 40a, an electrically isolating section 40b, and / or a resetting section 40c can each be present individually or in multiples. Two or all three sections can be combined in a single component or distributed across several components. Various possible designs and distributions are explained below by way of example. Their design features can be combined with one another in any way.

[0023] The thermal protection device 40 can be located at any point. It can be arranged completely, in particular with all component parts, or at least partially, i.e., with only a part of the component parts, according to one of the following arrangement variants, or distributed across two or three of the variants.

[0024] Preferably, the thermal protection device can be arranged at least partially at an electrical connection 23 of the magnetic coupling 20. More preferably, the thermal protection device can be integrated at least partially into a connection socket 24 of the magnetic coupling 20. Alternatively or additionally, the thermal protection device can preferably be integrated at least partially into a plug element 25, 25' of a connecting cable 30 of the magnetic coupling. Alternatively or additionally, the thermal protection device can be integrated at least partially into an adapter element 34, which can be arranged, or is arranged, particularly between a connection socket 24 of the magnetic coupling 20 and a connecting cable 30.

[0025] According to the present disclosure, at least a partial arrangement also includes a complete arrangement. An arrangement between a connector socket 24 and a connecting cable 30 can be a spatial intermediate arrangement and / or an intermediate arrangement with regard to the electrical wiring.

[0026] Alternatively or additionally, the thermal protection device 40 can be arranged at least partially on a receptacle of the housing of the magnetic coupling 20, in particular on a mounting receptacle 26. A preferred embodiment provides that a temperature-sensitive section 40a is present multiple times, wherein a first temperature-sensitive section 40a is arranged on an electrical connection 23 of the magnetic coupling 20 and at least one further temperature-sensitive section 40a is arranged on a receptacle of the housing of the magnetic coupling 20.

[0027] The thermal cut-out 40 can exclusively have a canceling effect on the electrical actuation of the magnetic clutch 20. Alternatively, the thermal cut-out 40 can also have a reset effect.

[0028] The thermal protection device 40 can preferably permanently prevent electrical activation after an overheating condition occurs. In particular, this can occur through a permanent change in the state of the thermal protection device, and furthermore, in particular, through at least partial destruction of a protective element 41. The protective element 41 can be of any design. It can be a (separate) fuse, in particular a fuse 43 of the thermal protection device 40. Alternatively or additionally, a protective element 41 can be an (optionally external) electrical overload protection device 46. An overload protection device 46 can be part of a connecting cable 30 and / or part of a magnetic coupling 20 and / or part of a lawnmower 1.

[0029] The thermal protection device 40 may temporarily prevent electrical actuation after an overheating condition occurs, and the thermal protection device 40 can be reset, in particular by manually actuating a reset element 42. The resettability, especially manual resettability, may depend on at least one further approval criterion. In other words, a reset may be prevented or excluded if and / or as long as at least one approval criterion for resetting is not met. Such an approval criterion may be verifiable in any way and by any means of verification.

[0030] A first approval criterion can be that the overheating condition has ceased. In other words, a reset, in particular a reset by manual actuation of a reset element 42, can only be permitted and / or become effective after the overheating condition has ceased.

[0031] Alternatively or additionally, an approval criterion can be an external interruption of the power supply to the magnetic clutch 20. In other words, a reset, in particular by manual actuation of a reset element, can only be permitted or become effective if and / or as soon as an external power supply to the magnetic clutch 20 is interrupted (in addition to the cancellation effect of the thermal protection).

[0032] The thermal protection device may temporarily interrupt electrical operation after an overheating condition occurs, whereby the thermal protection device 40 resets itself automatically, particularly after the overheating condition ceases. In this case, the reset may also be dependent on the same or further approval criteria that have already been explained.

[0033] Alternatively or additionally, a self-reset may be limited to a specific number of repetitions. If and / or once the limited number of repetitions is reached, a reset may only be permitted via manual operation.

[0034] Fig. Figures 3-12 show exemplary embodiments of a magnetic coupling 20 and a thermal fuse 40. In all examples shown, modifications to the arrangement of the thermal fuse according to the above descriptions are covered by the disclosure. In particular, a temperature-sensitive section 40a and / or an electrically isolating section 40b and / or a resetting section 40c can be added as desired and / or provided at the position shown in the example or at another position.

[0035] In the example of Fig. 3 and Fig. 4 is a thermal protection device 40 which can be arranged or is arranged at an electrical connection 23, in particular at a connection socket 24 of the magnetic coupling 20.

[0036] In the example shown, a temperature-sensitive section 40a is formed by a temperature-sensitive electrical fuse 43. This fuse may also simultaneously form an electrically isolating section 40b. In the example shown, the temperature-sensitive electrical fuse (melt-type fuse) 43 is connected to a magnetic coupling connection cable 30 by a series connection 49a. It may, in particular, be integrated into a connection socket 24 of the magnetic coupling and / or be integrated into or on a plug element of the connection cable 30 of the magnetic coupling. The fuse trips, in particular, due to an external heat input, and furthermore, in particular, due to heat transfer from the magnetic coupling 20 to the thermal fuse 40.

[0037] The thermal protection device 40 can include a thermal switch 44, 45. The thermal switch can have any design. For example, it can include a bimetallic switching element. Furthermore, after a change of state (opening or closing, depending on the design), a thermal switch 44, 45 can be held in its current switching state by a lockout mechanism. The lockout mechanism can have any design and / or react to any influences. In particular, the lockout mechanism can be a means of verifying the presence of at least one approval criterion for resetting.

[0038] A state lock can include or be formed by a hysteresis switching device. A state lock can include or be formed by a holding circuit that maintains the switching state after an overheating condition until a (regular) power supply to the magnetic clutch 20 is interrupted.

[0039] In the example of Fig. 5 and Fig. 6. The thermal protection device 40 includes a thermal switch 44, which is normally closed. The thermal switch 44 can be connected, in particular, by a contact for series connection 49a. When the thermal switch 44 is in its normally closed state, a power supply, and thus an electrical actuation of the magnetic clutch 20, is effectively transmitted at the electrical connection 23, in particular the terminal 24. If an overheating condition occurs, the thermal switch switches to the open state, so that the (generally externally applied) power supply to the magnetic clutch 20 is interrupted, or the electrical actuation of the magnetic clutch 20 is deactivated.

[0040] The thermal switch 24 is preferably designed to reset itself automatically after the overheating condition ceases, in particular to return to the normally closed state. The thermal switch 44 preferably allows a reset only after the overheating condition ceases. The thermal state 44 preferably allows a reset only when or as soon as an externally applied power supply is interrupted, for example, when the ignition of the lawnmower 1 is switched off. The thermal switch 44 preferably includes a suitable holding circuit for this purpose.

[0041] In the example of Fig. 7 and Fig. 8 The thermal protection 40 includes a thermal switch 45 that is normally open. Furthermore, an electrical overload protection 46 may be present, which reacts in particular to an overload in the power supply of the magnetic clutch 20. The overload protection 46 can be a component of the thermal protection and / or the cutting tool drive and / or a magnetic clutch connection cable 30. Alternatively or additionally, an overload protection 46 can be separate / external and, for example, be a component of the lawnmower 1.

[0042] The normally open thermal switch 45 is preferably connected in parallel to the power supply of the magnetic clutch 20 and, upon the occurrence of an overheating condition, establishes a low-resistance connection, in particular a short circuit, so that the at least one electrical overload protection device 46 trips and interrupts the power supply. In other words, a thermal switch 45 can be configured to bridge the power supply to the magnetic clutch 20 with a low resistance when an overheating condition occurs.

[0043] In the example of Fig. 7 and Fig. 8 is a temperature-sensitive section 40a formed by the normally open thermal switch 45, while an electrically isolating section 40b and possibly a resetting section 40c are formed by an (possibly external) overload protection device 46.

[0044] In contrast, in the example of Fig. 5 and Fig. 6. A temperature-sensitive section 40a and an electrically isolating section 40b are formed on the one hand by a normally closed thermal switch 44. Optionally, a resettable section 40c can also be formed by the thermal switch 44 or the holding circuit.

[0045] In the example of Fig. 9 and Fig. The thermal protection device 40 comprises a control unit 47 and a temperature sensor 48. The temperature sensor 48 can be present one or more times. The temperature sensor 48 may also be an external component, with the control unit 47 being connected or connectable to the at least one external temperature sensor 48.

[0046] The at least one temperature sensor 48 preferably detects the temperature of the magnetic coupling 20, more preferably at least a connection temperature and / or a housing temperature and / or an output element temperature.

[0047] In the example shown, a temperature sensor 48 is provided which detects the connection temperature.

[0048] The control unit 47 switches or controls the power supply to the magnetic coupling 20 based on at least one detected temperature. The control unit 47 can comprise one or more control sections. In particular, at least one control section is provided that checks the presence of a reset authorization criterion. Alternatively or additionally, at least one control section can be provided that allows an independent reset (only) for a limited number of repetitions.

[0049] The control unit 47 can be an independent component of a cutting tool drive 3 and / or a magnetic clutch connection cable 30. Alternatively or additionally, the control unit 47 can be a component of a device control unit of a lawn mower 1 or interact with a device control unit of a lawn mower 1 to deactivate the electrical actuation of the magnetic clutch and / or to effect or allow a reset in the event of an overheating condition.

[0050] The control unit 47 can preferably be configured to output, independently or in conjunction with a device control unit, a switching state of the thermal protection device 40 and / or a recommendation for action and / or an error message. The output can be provided in any manner, for example by a suitable indication on the lawnmower 1 and / or by transmitting a message and / or a command to an external device, in particular a personal mobile device such as a smartphone.

[0051] In the example of Fig. 11 and Fig. Figure 12 shows an example of a normally closed thermal switch 44, the operation of which is similar or the same as that described with regard to Fig. 5 and Fig. It can be one of the 6 explained design variants.

[0052] During the in Fig. 5 and Fig. 6 illustrated thermal switches 44 are formed by an electronic component, in particular an integrated circuit, or comprise an electronic component / integrated circuit, the example of Fig. 11 and Fig. 12 an electrical or electromechanical thermal switch, which here is formed in particular by a thermal relay 51.

[0053] The thermo-relay 51 can be present one or more times. It can be combined with at least one electronic thermal switch 44.

[0054] In the example of Fig. 11 and Fig. 12 the thermo-relay 51 is connected by a contact for series connection 49a to a connection socket 24 and / or a plug element 25 of a connecting cable 30.

[0055] The thermo-relay 51 can, for example, include a switch that opens by the application of heat, which is triggered, for example, by a bimetallic switching element.

[0056] Furthermore, the thermo-relay 51 (as well as a thermal switch 44,45) can include a resetting section 40c, which in the example shown is formed by a reset mechanism or includes a reset mechanism.

[0057] In the example of Fig. 11 and Fig. Section 12 consists of a temperature-sensitive section 40a and an electrically isolating section 40b formed by the thermo-relay 51. The thermo-relay 51 can also be a resettable section 40c.

[0058] Furthermore, in the example shown, a thermal protection device is arranged on a housing 25 of the magnetic coupling 20, more specifically on a receptacle of the housing 25 of the magnetic coupling and, again, preferably on a mounting receptacle 26 of the magnetic coupling 20.

[0059] The features, modes of operation and / or arrangement types that have been explained with regard to the design variants can be combined with each other or substituted for each other in any way.

[0060] A magnetic coupling connection cable 30 according to the present disclosure can independently possess all the features described above for thermal protection. In particular, the magnetic coupling connection cable 30 can include its own thermal protection 40, which, in the event of an overheating condition, disables the electrical actuation of the magnetic coupling 20.

[0061] The thermal protection device 40 can react to an overheating condition of the magnetic coupling 20, which occurs in particular when the temperature of the magnetic coupling exceeds a predefined temperature limit.

[0062] The thermal protection device 40 can be at least partially integrated into a plug element 25 of the magnetic coupling connection cable 30.

[0063] In the intended assembly state, the thermal protection device 40 can preferably be arranged on a receptacle of the housing of the magnetic coupling 20, in particular on a mounting receptacle 26 and / or on an electrical connection 23 of the magnetic coupling 20. The arrangement can be provided partially or completely, in particular at least for a temperature-sensitive section 40a and / or an electrically isolating section 40b. Reference sign 1 lawnmower 2 lawn cutting tools 3 Cutting tool drive 4 Motor drive / internal combustion engine 5 Gearbox / Belt drive 6 First cutting unit 7 Second cutting unit 20 Magnetic coupling 21 Drive element 22 Output element 23 Electrical connection 24 connection socket 25 cases 26 Mounting bracket 30 magnetic coupling connection cables 31 First line 32 Second line 33 Plug-in element 34 Adapter element 40 Thermal protection 40a Temperature-sensitive section 40b Electrically isolating section 40c Resetting Section 41 Protective element 42 Reset element / mechanical reset switch 43 Thermal fuse / fuse 44 Thermal switches (normally closed) 45 Thermal switches (normally open) 46 Electrical overload protection 47 Control 48 Temperature sensor 49a Contact for series connection 49b Contact for parallel circuit 50 sensor cable(s) 51 Thermo-relays (normally closed)

Claims

Cutting tool drive (3) for a lawn cutting tool (2) of a lawn mower (1), wherein the cutting tool drive (3) comprises a clutch, characterized in that the clutch is designed as an electrically actuated magnetic clutch (20) and the cutting tool drive (3) comprises a thermal protection device (40) which cancels the electrical actuation of the magnetic clutch when an overheating condition occurs. Cutting tool drive according to the preceding claim, wherein the magnetic coupling (20) switches or controls a torque transmission between a drive element (21) of the magnetic coupling and an output element (22) of the magnetic coupling, wherein in particular the drive element (21) is connectable or connected to a motor drive (4) on the input side, and / or wherein in particular the output element (22) is connectable or connected to the lawn cutting tool (2) on the output side in a torque-conducting manner. Cutting tool drive according to claim 1 or 2, wherein the magnetic coupling (20) causes the torque transmission when and / or as long as the electrical actuation is active; AND / OR prevents it when and / or as long as the electrical actuation is inactive. Cutting tool drive according to one of the preceding claims, wherein the magnetic coupling (20) comprises a first coupling unit, in particular a first coupling disc connected to the drive element (21), and a second coupling unit, in particular a second coupling disc connected to the output element (22), and wherein the coupling units can be brought into engagement with each other by electrical actuation. Cutting tool drive according to one of the preceding claims, wherein the thermal protection (40) reacts to an overheating condition of the magnetic coupling (20), which occurs in particular when a temperature of the magnetic coupling, furthermore in particular a connection temperature or a housing temperature of the magnetic coupling (20) exceeds a predefined temperature limit. Cutting tool drive according to one of the preceding claims, wherein the thermal protection (40) comprises a temperature-sensitive section (40a) and in particular further an electrically isolating section (40b) and / or a resetting section (40c). Cutting tool drive according to one of the preceding claims, wherein the thermal protection is at least partially arranged at an electrical connection (23) of the magnetic coupling (20), in particular - is integrated into a connection socket (24) of the magnetic coupling; AND / OR - is integrated into a plug element (25) of a connection cable (30) of the magnetic coupling; AND / OR - is integrated into an adapter element (34) that can be arranged or is arranged between a connection socket (24) of the magnetic coupling (20) and a connection cable (30). Cutting tool drive according to one of the preceding claims, wherein the thermal protection (40) is at least partially arranged on a receptacle of the housing of the magnetic coupling, in particular on a mounting receptacle (26). Cutting tool drive according to one of the preceding claims, wherein the thermal protection device (40) permanently prevents electrical actuation after the occurrence of the overheating state, wherein in particular a permanent change of state of the thermal protection device (40) occurs, further in particular an at least partial destruction of a protective element (41); or temporarily prevents electrical actuation, wherein the thermal protection device (40) can be reset, in particular by manual actuation of a reset element (42), further in particular a reset is permitted and / or becomes effective only after the overheating state has ceased;- temporarily prevents electrical actuation, wherein the thermal protection (40) resets itself automatically, particularly after the overheating condition has ceased, and furthermore resets itself automatically for a limited number of repetitions, AND / OR furthermore particularly if an additional reset approval criterion is present.; Cutting tool drive according to one of the preceding claims, wherein the thermal protection comprises: - a temperature-sensitive electrical fuse (43); OR - a normally closed thermal switch (44) which interrupts the power supply to the magnetic clutch (20) when the overheating condition occurs; OR - a normally open thermal switch (45) which is connected in parallel in the power supply to the magnetic clutch (20) and which establishes a low-resistance connection, in particular a short circuit, when the overheating condition occurs, so that an electrical overload protection device (46) trips and interrupts the power supply; OR - a control unit (47) and a temperature sensor (48), wherein the temperature sensor (48) detects the temperature of the magnetic clutch (20) and the control unit (47) switches or controls the power supply to the magnetic clutch (20) based on this detected temperature. Magnetic coupling connection cable (30) for the electrical supply of a magnetic coupling (20) of a cutting tool drive (3) for a lawn mower (1), wherein the magnetic coupling connection cable (30) includes a thermal protection device (40) which, in the event of an overheating condition, cancels the electrical actuation of the magnetic coupling (20). Magnetic coupling connection cable (30) according to the preceding claim, wherein the thermal protection (40) reacts to an overheating condition of the magnetic coupling (20), which occurs in particular when a temperature of the magnetic coupling, furthermore in particular a connection temperature or a housing temperature of the magnetic coupling (20) exceeds a predefined temperature limit. Magnetic coupling connection cable (30) according to one of the preceding claims, wherein the thermal protection is at least partially integrated in a plug element (25) of the magnetic coupling connection cable (30). Magnetic coupling connection cable (30) according to one of the preceding claims, wherein the thermal protection (40) is arranged on a receptacle of the housing of the magnetic coupling, in particular on a mounting receptacle (27). Lawn mower comprising a cutting tool drive (2) according to any one of the preceding claims 1 to 10 and / or a magnetic coupling connection cable (30) according to any one of the preceding claims 11 to 14, optionally further comprising a motor drive (4) and / or a device control.

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