阅读说明：本技术 用于园艺的手持式剪切机和与手持式剪切机有关的方法 (Hand-held shears for horticulture and methods relating to hand-held shears ) 是由 彼得·鲁道夫 费利克斯·韦格霍夫 于 2018-05-02 设计创作，主要内容包括：本发明公开一种用于园艺目的的手持式剪切机(2)。第一组切割刀片(6)或第二组切割刀片(8)能一次一个地连接至剪切机(2)的壳体(4),以由电动机的输出轴驱动。手持式剪切机(2)被配置成当第一组切割刀片(6)连接到输出轴(46)时提供第一组切割刀片(6)中的第一刀片(16)的第一最大速度,并且当第二组切割刀片(8)连接到输出轴(46)时,提供第二组切割刀片(8)中的第一刀片(20)的第二最大速度。(The invention discloses a hand-held shears (2) for gardening purposes. The first set of cutting blades (6) or the second set of cutting blades (8) can be connected to the housing (4) of the shear (2) one at a time to be driven by the output shaft of the electric motor. The hand-held shears (2) is configured to provide a first maximum speed of the first blade (16) in the first set of cutting blades (6) when the first set of cutting blades (6) are connected to the output shaft (46), and to provide a second maximum speed of the first blade (20) in the second set of cutting blades (8) when the second set of cutting blades (8) are connected to the output shaft (46).)

1. A hand-held shearer (2) for gardening purposes, comprising

A shell (4) which is provided with a plurality of grooves,

a motor (40) arranged within the housing (4),

a battery (42) connectable to the motor (40), an

A first set of cutting blades (6) and/or a second set of cutting blades (8), wherein

The first set of cutting blades (6) and the second set of cutting blades (8) being connectable to the housing (4) one at a time to be driven by an output shaft (46) of the motor (40),

it is characterized in that the preparation method is characterized in that,

the hand-held shearer (2) is configured to: providing a first maximum speed of a first blade (16) in the first set of cutting blades (6) when the first set of cutting blades (6) are connected to the output shaft (46), and providing a second maximum speed of a first blade (20) in the second set of cutting blades (8) when the second set of cutting blades (8) are connected to the output shaft (46).

2. The hand-held shearer (2) of claim 1, wherein the first maximum speed is lower than the second maximum speed.

3. The hand-held shearer (2) of claim 1 or 2, wherein the first maximum speed is a first maximum reciprocating speed of the first blade (16) in the first set of cutting blades (6), and wherein the second maximum speed is a second maximum reciprocating speed of the first blade (20) in the second set of cutting blades (8).

4. A hand-held shearer (2) according to any of the preceding claims, wherein the first set of cutting blades (6) is configured for mowing, and wherein the second set of cutting blades (8) is configured for cutting shrubs.

5. A hand-held shearer (2) according to any of the preceding claims, comprising a control unit (50) connected to the motor (40) to control the rotational speed of the motor (40) and its output shaft (46), the control unit (50) being configured to drive the motor (40) at a lower rotational speed to provide the first maximum speed and to drive the motor (40) at a higher rotational speed to provide the second maximum speed.

6. The hand-held shearer (2) of claim 5, comprising a switch (52, 52') connected to the control unit (50), wherein the switch (52, 52') is configured for providing an input to the control unit (50) to control the rotational speed of the motor (40) between the lower rotational speed and the higher rotational speed.

7. The hand-held shearer (2) of claim 6, wherein the switch (52) is a manually actuatable switch (52).

8. The hand-held shearer (2) of claim 6, wherein the switch (52') is actuated by the first set of cutting blades (6) when the first set of cutting blades (6) is connected to the housing (4) and/or the switch (52') is actuated by the second set of cutting blades (8) when the second set of cutting blades (8) is connected to the housing (4).

9. A hand-held shearer (2) according to any of the preceding claims, wherein a gearbox (48) is arranged between the output shaft (46) of the motor (40) and the first blade of the first set of cutting blades (6) when the first set of cutting blades is connected to the housing (4), or a gearbox (48) is arranged between the output shaft (46) of the motor (40) and the first blade of the second set of cutting blades (8) when the second set of cutting blades is connected to the housing (4).

10. The hand-held shearer (2) of claim 9, wherein the gearbox (48) is a first gearbox with a first gear ratio connected to the first blade (16) in the first set of cutting blades (6), and wherein the gearbox (48) is a second gearbox with a second gear ratio connected to the first blade (20) in the second set of cutting blades (8).

11. The hand-held shearer (2) of any preceding claim, comprising the first set of cutting blades (6) and the second set of cutting blades (8).

12. A method of operating a hand-held shearer (2) for gardening purposes, the hand-held shearer (2) comprising a housing (4), a motor (40) arranged within the housing (4), a battery (42) connectable to the motor (40), a first set of cutting blades (6) and a second set of cutting blades (8), wherein the first set of cutting blades and the second set of cutting blades are connectable to the housing (4) one at a time to be driven by an output shaft (46) of the motor (40), and wherein the method (100) comprises the steps of:

-operating a first blade (16) of the first set of cutting blades (6) at a first maximum speed when the first set of cutting blades (6) is connected to the output shaft (46), and

-operating a first blade (20) of the second set of cutting blades (8) at a second maximum speed when the second set of cutting blades (8) is connected to the output shaft (46).

Technical Field

The present disclosure relates to hand-held shears for horticultural purposes, and to a method for operating a hand-held shear for horticultural purposes.

Background

Battery powered hand held shears for horticultural purposes are known. One type of such shears may be used to cut grass with one set of cutting blades applied, and may be used to cut branches, for example in brush, with a different set of cutting blades applied. That is, the two sets of cutting blades are interchangeably connected to the housing of the hand-held shears.

The battery of the hand-held shearer is rechargeable and provides electrical power to an electric motor disposed in the housing of the shearer. The motor in turn drives an associated set of cutting blades attached to the housing.

The working time of battery powered hand held shears is significant. Thus, the friction between the individual cutting blades in a set of cutting blades of such a shear is reduced, for example by applying a layer of PTFE or oily black oxide on the surface of each cutting blade. Moreover, any abutment pressure between the cutting blades in a set of cutting blades has been adapted to the task associated with a particular set of cutting blades. That is, a relatively high abutment pressure is used for a set of cutting blades that cut grass, while a relatively low or no abutment pressure is used for a set of cutting blades that cut branches. Thus, at least when idle, i.e. when the cutting blade is not performing a cut, less energy is consumed when the cutting blade for cutting branches is connected to the trimmer than when the cutting blade for cutting grass is connected to the trimmer.

Disclosure of Invention

It is an object to provide a battery powered hand held shears for horticultural purposes in which the operating time is improved.

According to one aspect, the object is achieved by a hand-held shears for horticultural purposes, the shears comprising: the cutting blade assembly includes a housing, a motor disposed within the housing, a battery connectable to the motor, and a first set of cutting blades and/or a second set of cutting blades. The first and second sets of cutting blades can be attached to the housing one at a time to be driven by the output shaft of the motor. The handheld shears is configured to provide a first maximum speed of the first blade in the first set of cutting blades when the first set of cutting blades is connected to the output shaft and a second maximum speed of the first blade in the second set of cutting blades when the second set of cutting blades is connected to the output shaft.

Since the hand-held shears are configured to provide different maximum blade speeds depending on which of the first and second sets of cutting blades is connected to the output shaft of the motor, the energy consumption of the motor from the battery will be applicable to the relevant set of cutting blades connected to the output shaft of the motor, and thus to the relevant cutting task to be performed. Thus, only the electrical energy required for a particular cutting task will be consumed from the battery. As a result, the above object is achieved.

Another object is to provide a method for operating a battery powered hand held shears for horticultural purposes, wherein the operating time of the hand held shears is improved.

According to another aspect, there is provided a method for operating a hand-held trimmer for gardening purposes, the hand-held trimmer comprising a housing, an electric motor arranged within the housing, a battery connectable to the electric motor, a first set of cutting blades and a second set of cutting blades, wherein the first set of cutting blades and the second set of cutting blades are connectable to the housing one at a time to be driven by an output shaft of the electric motor, and wherein the method comprises the steps of:

-operating a first blade of the first set of cutting blades at a first maximum speed when the first set of cutting blades are connected to the output shaft, and

-operating a first blade of the second set of cutting blades at a second maximum speed when the second set of cutting blades are connected to the output shaft.

The method comprises the following steps: when the first set of cutting blades is connected to the output shaft, the first blade of the first set of cutting blades is operated at a first maximum speed, and when the second set of cutting blades is connected to the output shaft, the first blade of the second set of cutting blades is operated at a second maximum speed, so that the energy consumption of the motor from the battery will be adapted to the relevant set of cutting blades connected to the output shaft of the motor, and thus to the relevant cutting task to be performed. Thus, only the electrical energy required for a particular cutting task will be consumed from the battery. As a result, the above object is achieved.

The inventors have realized that associating the maximum speed of the blades in a set of cutting blades with an associated set of cutting blades connected to the output shaft of the motor provides for using only the necessary electrical energy to perform a specific cutting task, for which the associated set of cutting blades is designed. Thus, the working time of the battery of the hand-held shears may be increased compared to prior art hand-held shears where one common maximum speed is used for all cutting tasks requiring the highest speed of one blade to determine the common maximum speed.

The hand-held shears may be configured for many different cutting operations to be performed in the garden. Different sets of cutting blades may be used for different cutting operations. Each of the different sets of cutting blades may be designed for a particular cutting operation, such as mowing or cutting brush. The set of cutting blades may include two cutting blades arranged adjacent to each other. At least one blade of the set of cutting blades may be driven by a motor to perform, for example, a reciprocating motion. One or more linkages and/or gearing arrangements may be disposed between the output shaft of the motor and at least one driven blade of the set of cutting blades. Thus, at least one driven blade of a set of cutting blades may be indirectly driven by the motor. Both cutting blades may perform a shearing motion when at least one blade of a set of cutting blades is driven. Each of the cutting blades in the set of cutting blades includes at least one cutting edge. Each of the cutting blades in a set of cutting blades may include a plurality of cutting edges. Depending on the set of cutting blades, the handheld shears may be configured to operate at a fixed first maximum speed or a fixed second maximum speed. Optionally, depending on the cutting blade set, the hand-held shears may be configured to operate at one or more speeds up to a maximum speed corresponding to the first maximum speed or the second maximum speed. The first and second maximum speeds may be provided electronically or mechanically.

According to an embodiment, the first set of cutting blades may be configured for mowing while the second set of cutting blades may be configured for cutting shrubs. In this way, the first and second sets of cutting blades may be designed for two specific cutting tasks.

Furthermore, since mowing and cutting shrubs require different kinds of cutting blades working under different operating conditions, the inventors have realized that this may save electrical energy by utilizing a first maximum speed for a first set of cutting blades when cutting grass and a second maximum speed for a second set of cutting blades when cutting shrubs. That is, cutting the shrub requires high kinetic energy from the rotor of the motor in order for the second set of cutting blades to cut the branches of the shrub. In the case of a relatively compact and lightweight electric motor of a hand-held tool, such high kinetic energy is provided by the high rotational speed of the electric motor. The inventors have realized that using the motor at such a high rotational speed results in an excessive use of electrical energy when mowing with the first set of cutting blades. First, mowing does not require the same kinetic energy as cutting shrubs. Second, in a first set of cutting blades configured for mowing, the blades are arranged against each other. Thus, the friction affects the movement of the first blade in the first set of cutting blades. Thus, by using a lower first maximum speed for the first blade of the first set of cutting blades, electrical energy may be saved while still providing good mowing capability.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

Drawings

The various aspects and/or embodiments of the present invention, including the specific features and advantages thereof, will be readily understood from the following detailed description and the accompanying drawings, in which:

figures 1a-1d show a hand-held shear according to an embodiment,

figures 2a and 2b show two cutting blades of the first set of cutting blades,

figures 3a and 3b show two cutting blades of the second set of cutting blades,

figure 4a shows the hand-held shears with their housing open,

figure 4b shows a cross-section through a hand-held shear,

FIG. 5 schematically illustrates an embodiment of a control system for a hand-held shearer, and

fig. 6 illustrates a method for operating a hand-held shears for gardening purposes.

Detailed Description

Aspects and/or embodiments of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions may not be described in detail for brevity and/or clarity.

Fig. 1a-1d show a hand-held shearer 2 according to an embodiment. The hand-held shears 2 are configured for gardening purposes. The hand-held shearer 2 is battery powered.

The hand-held shearer 2 includes a housing 4, and either a first set of cutting blades 6 (as shown in fig. 1a and 1 b) or a second set of cutting blades 8 (as shown in fig. 1c and 1 d). The first set of cutting blades 6 and the second set of cutting blades 8 can be attached to the housing 4 one at a time. The housing 4 is configured to be attached to either of the first set of cutting blades 6 and the second set of cutting blades 8. The handheld shears 2 may be provided to a user, for example sold to a user, with only one of the first and second sets of cutting blades 6, 8.

Alternatively, the handheld shears 2 may comprise a first set of cutting blades 6, and a second set of cutting blades 8. That is, the shearer kit may include a housing 4, a first set of cutting blades 6 (as shown in fig. 1a and 1 b), and a second set of cutting blades 8 (as shown in fig. 1c and 1 d). Also, the first set of cutting blades 6 and the second set of cutting blades 8 can be attached to the housing 4 one at a time. Thus, the hand-held shears 2 may be provided to a user, for example sold to a user, as a shear kit comprising a first set of cutting blades 6 and a second set of cutting blades 8.

The housing 4 comprises a handle portion 10 and a connecting portion 12. The handle portion 10 is configured to be held by a user with the handheld shears 2. The handle portion 10 may be configured to be held by only one hand. The attachment portion 12 is configured for attaching either the first set of cutting blades 6 or the second set of cutting blades 8 thereto. The first set of cutting blades 6 includes a first attachment portion 14 and two cutting blades 16, 16'. The second set of cutting blades 8 comprises a second attachment portion 18 and two cutting blades 20, 20'. The first attachment portion 14 and the second attachment portion 18 are configured for connection to the connection portion 12 of the housing 4.

Any suitable attachment mechanism may be used to releasably attach either the first set of cutting blades 6 or the second set of cutting blades 8 to the housing 4. In these embodiments, the connection mechanism includes a protruding element 22 disposed in the connection portion 12 and a groove 24 disposed in the first and second attachment portions 14, 18. The protruding elements 22 engage with the recesses 24 to securely attach the first set of cutting blades 6 or the second set of cutting blades 8 to the housing 4.

These projecting elements 22 are resiliently arranged in the connecting portion 12 of the housing 4. These protruding elements 22 can be at least partially pulled into the housing 4 by one or more buttons 26. Thus, a user may actuate one or more buttons 26 to disengage the set of cutting blades 6, 8 from the housing 4. Actuating one or more buttons 26 will withdraw the protruding elements 22 from engagement with the grooves 24.

In fig. 1a and 1b, an embodiment of a first set of cutting blades 6 configured for mowing is shown. In fig. 1c and 1d, an embodiment of a second set of cutting blades 8 configured for cutting shrubs is shown. Naturally, a set of cutting blades designed for other cutting purposes may be connected to the housing 4.

Fig. 2a and 2b show in more detail two cutting blades 16, 16' of the first set of cutting blades 6 of fig. 1a and 1 b. Fig. 2a shows a top view of the two cutting blades 16, 16', and fig. 2B shows a cross section of the two cutting blades 16, 16' along the line B-B in fig. 2 a.

A first blade 16 of the two cutting blades 16, 16' is reciprocated relative to a second blade 16' of the two cutting blades 16, 16' in a known manner. The first blade 16 reciprocates in the direction indicated by arrow 28. That is, the first blade 16 reciprocates substantially perpendicular to the longitudinal direction 30 of the hand-held shears. The longitudinal direction 30 extends along both the handle portion 10 and the cutting blades 16, 16' of the first set of cutting blades 6, see also fig. 1 a.

Each of the two cutting blades 16, 16' is provided with a number of cutting edges 32. The reciprocating motion of the first blade 16 produces a shearing motion between the pair of cutting edges 32.

The first set of cutting blades 6 is configured for mowing, in particular due to the first blade 16 abutting the second blade 16' such that the cutting edges 32 cut firmly against each other.

Fig. 3a and 3b show in more detail two cutting blades 20, 20' of the second set of cutting blades 8 in fig. 1c and 1 d. Fig. 3a shows a top view of the two cutting blades 20, 20 'and fig. 3B shows a cross section of the two cutting blades 20, 20' along the line B-B in fig. 3 a.

In a known manner, a first blade 20 of the two cutting blades 20, 20' is reciprocated relative to a second blade 20' of the two cutting blades 20, 20 '. The first blade 20 reciprocates in the direction indicated by arrow 34. That is, the first blade 20 reciprocates generally along the longitudinal direction 30 of the hand-held shears. The longitudinal direction 30 extends along both the handle portion 10 and the cutting blades 20, 20' of the second set of cutting blades 8, see also fig. 1 c.

Each of the two cutting blades 20, 20' has a plurality of cutting edges 36. The reciprocating motion of the first blade 20 causes a shearing motion between the pairs of cutting edges 36.

The second set of cutting blades 8 is configured for cutting shrubs, in particular because the first blade 20 is arranged at a small distance from the second blade 20 'such that the first blade 20 is free to reciprocate without frictional engagement with the second blade 20'.

Fig. 4a and 4b show the hand-held shears 2 of fig. 1a-1d with a first set of cutting blades 6 attached. Fig. 4a shows the hand-held shears 2 with the housing 4 open, and shows a partial perspective view in dashed lines. Fig. 4b shows a cross section of the hand-held shear 2.

The hand-held shearer 2 comprises an electric motor 40 arranged within the housing 4 and a battery 42 connectable to the electric motor 40. In these embodiments, the battery 42 may be connected to the motor 40 via a user-operable switch 44. To switch the hand-held shears 2 on and off, the user manipulates a user-operable switch 44. The user operable switch 44 may be biased towards the off position of the switch 44. The battery 42 may be rechargeable.

By way of example only, the motor 40 may be a 50 watt direct current motor having a nominal voltage in the range of 3 to 12 volts. Its maximum rotational speed may be in the range 12000 to 22000 rpm.

By way of example only, the battery 42 may be a lithium ion type battery having a nominal voltage of 3.6V and may have a capacity of 2-3 Ah.

The motor 40 includes an output shaft 46 that rotates when electrical power is provided to the motor 40 from the battery 42. That is, when the user moves the user-operable switch 44 to its on position, power is supplied from the battery 42 to the motor 40.

When the motor rotates, the output shaft 46 drives the associated set of cutting blades connected to the housing 4, i.e. the first set of cutting blades 6 in the case shown in fig. 4a and 4 b. The first and second sets of cutting blades may be attached to the housing 4 one at a time, as shown in fig. 1a-1d, to be driven by the output shaft 46 of the motor 40.

The handheld shears 2 is configured to provide a first maximum speed of the first blade 16 in the first set of cutting blades 6 when the first set of cutting blades 6 are attached to the output shaft 46, and a second maximum speed of the first blade 20 in the second set of cutting blades 8 when the second set of cutting blades 8 are attached to the output shaft 46. This can be achieved in a number of different ways, as will be discussed further below.

According to some embodiments, the handheld shears 2 may be configured to operate at a fixed speed (first maximum speed or second maximum speed) depending on the set of cutting blades 6, 8 attached to the housing 4. That is, the first maximum speed is a fixed speed, which corresponds to a fixed rotational speed of the motor 40. When the first set of cutting blades 6 is attached to the housing 4 and the motor 40 is on, the motor accelerates to a fixed rotational speed, thereby providing a fixed first maximum speed of the first blade 16 in the first set of cutting blades 6. Similarly, the second maximum speed is a fixed speed, which corresponds to a fixed rotational speed of the motor 40. When the second set of cutting blades 6 is attached to the housing 4 and the motor 40 is switched on, the motor accelerates to a fixed rotational speed, thereby providing a fixed second maximum speed of the first blade 20 in the second set of cutting blades 8.

The hand-held shears 2 may comprise a switching device for setting the first and/or second maximum speed. The fixed first and/or second maximum speeds may be set at different levels, for example, to provide different operating modes of the hand-held shears 2, such as an acceleration mode with a higher first and/or second maximum speed and an economy mode with a lower first and/or second maximum speed.

According to an alternative embodiment, the handheld shears 2 may be configured to operate at one or more speeds up to a maximum speed corresponding to the first maximum speed or the second maximum speed, depending on the set of cutting blades attached to the housing 4. That is, the first blade 16 of the first set of cutting blades 6 may be operated steplessly or in multiple steps up to the first maximum speed. Thus, when the first set of cutting blades 6 is attached to the housing 4, the motor 40 may be operated steplessly or in multiple steps to provide different speeds of the first blade 16 in the first set of cutting blades 6 up to the first maximum speed. Similarly, the first blade 20 of the second set of cutting blades 8 may be operated steplessly or in multiple steps up to the second maximum speed. Thus, when the second set of cutting blades 8 is connected to the housing 4, the motor 40 may be operated steplessly or in multiple steps to provide different speeds of the first blade 20 in the second set of cutting blades 8 up to the first maximum speed.

The first maximum speed is a nominal speed that is reached when the voltage of the battery 42 is at a nominal voltage. Similarly, the second maximum speed is a nominal speed that is reached when the voltage of the battery 42 is at a nominal voltage. In practical use of the hand-held shearer 2, the maximum speed depends on the available voltage of the battery 42. A newly charged battery will provide a higher voltage and thus a higher maximum rotational speed than a partially discharged battery. Moreover, the maximum speed may only be compared and/or evaluated when the hand-held shears 2 is operating without cutting (i.e. without any load). That is, during cutting with the hand-held shears 2, the load on the hand-held shears 2 varies greatly and naturally also affects the speed of the blades 16, 20 in one set of cutting blades 6, 8.

According to one embodiment, the first maximum speed may be lower than the second maximum speed.

According to one embodiment, the first maximum speed may be a first maximum reciprocating speed of the first blade 16 in the first set of cutting blades 6, and the second maximum speed may be a second maximum reciprocating speed of the first blade 20 in the second set of cutting blades 8.

The reciprocating speed may be measured, for example, by: the number of times the two cutting edges 32, 36 of a set of cutting blades 6, 8 perform a shearing movement per unit time.

Purely by way of example, the first maximum reciprocating speed may be 800 reciprocations/minute for the first set of cutting blades 6, and the second maximum reciprocating speed may be 1100 reciprocations/minute for the second set of cutting blades 8. If these sets of cutting blades 6, 8 have cutting edges 32, 36 on opposite sides of the reciprocating blade portion, as in the embodiment shown in e.g. fig. 2a and 3a, each reciprocation provides two cuts with an associated set of blades 6, 8. Thus, in such an embodiment, the above example provides 1600 cuts/minute for the first maximum speed and 2200 cuts/minute for the second maximum speed.

In the illustrated embodiment, the first and second sets of cutting blades 6, 8 are indirectly driven by the output shaft 46. The gearbox 48 is arranged between the output shaft 46 of the motor 40 and the first blade of the first set of cutting blades 6 when the first set of cutting blades is attached to the housing 4, or the gearbox 48 is arranged between the output shaft 46 of the motor 40 and the first blade of the second set of cutting blades 8 when the second set of cutting blades is attached to the housing 4.

In these embodiments, the gear box 48 includes two cogwheels 47, 49, namely one small cog wheel 47 connected to the output shaft 46 and one large cog wheel 49 connected to the linkage and to the first blade in the associated set of cutting blades 6, 8. The linkage is configured to provide, for example, reciprocating motion of the first blade in a known manner.

By way of example only, the gear ratio of the gearbox 48 may be 15:1 or 20: 1.

According to some embodiments, the hand-held shears 2 may comprise a control unit 50 connected to the motor 40 for controlling the rotational speed of the motor 40 and its output shaft 46. The control unit 50 may be configured to drive the motor 40 at a lower rotational speed to provide a first maximum speed and to drive the motor 40 at a higher rotational speed to provide a second maximum speed. In this way, a first maximum speed may be provided when the first set of cutting blades 6 is attached to the housing 4 and a second maximum speed may be provided when the second set of cutting blades 8 is attached to the housing 4.

The hand-held shears 2 may comprise a switch 52 connected to the control unit 50. The switch 52 may be configured to provide an input to the control unit 50 to control the rotational speed of the motor 40 between a lower rotational speed and a higher rotational speed. In this way, the first maximum speed may be provided by a lower rotational speed of the motor 40 when the first set of cutting blades 6 is attached to the housing 4, and the second maximum speed may be provided by a higher rotational speed of the motor 40 when the second set of cutting blades 8 is attached to the housing 4.

In these embodiments, the switch 52 is a manually actuatable switch. Thus, a user of the hand-held shears 2 manipulates the switch 52 to provide a first maximum speed when the first set of cutting blades 6 is attached to the housing 4 and a second maximum speed when the second set of cutting blades 8 is attached to the housing 4.

Fig. 5 schematically shows an embodiment of the control system 54 of the hand-held shears 2. The hand-held shearer 2 can be a hand-held shearer according to any of the embodiments described above.

The control system 54 includes a control unit 50, which may take the form of substantially any suitable type of processor circuit or microcomputer, such as circuitry for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, processing circuitry, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic circuitry that may interpret and execute instructions. The control system 54 may include a memory unit. The control unit 50 is connected to a memory unit which provides, for example, stored program code and/or stored data to the control unit 50, which the control unit 50 requires for calculations. The control unit 50 may also be adapted to store part of the calculation or the final result in the memory unit. A memory unit may comprise a physical device used for temporarily or permanently storing data or programs (i.e., sequences of instructions).

The control unit 50 is connected to the switches 44, 52' and the motor 40. The position of the switches 44, 52 provides control instructions to the control unit 50 to control the motor 40. Such control may involve the operation of the hand-held shears 2 discussed above:

when the user of the hand-held shears 2 manipulates the switch 44, the motor 40 is switched on and off,

switching between lower and higher rotational speed limit settings when the switches 52, 52' are operated, and

controlling the rotational speed of the motor 40, for example to a lower rotational speed, when the first set of cutting blades 6 is attached to the housing 4; or to control the speed of the motor 40 to a higher speed when the second set of cutting blades 8 is attached to the housing 4. This can be achieved, for example, by PWM control of the motor 40.

In addition, the control unit 50 may control charging of the battery 42.

Within the dashed line of fig. 5, an alternative embodiment of the control system 54 is shown. In these embodiments, the switch 52 'is actuated by the first set of cutting blades 6 when the first set of cutting blades 6 are attached to the housing 4, and/or the switch 52' is actuated by the second set of cutting blades 8 when the second set of cutting blades 8 are attached to the housing 4. In this way, the first and second maximum speeds are automatically established by the associated set of cutting blades 6, 8 which operate the switch 52'. For example, the first set of cutting blades 6 may manipulate switch 52' while the second set of cutting blades 8 may not manipulate switch 53, or vice versa. Each of the first set of cutting blades 6 and the second set of cutting blades 8 may manipulate a different kind of switch to a different position.

According to an alternative embodiment, the first maximum speed and the second maximum speed may be provided mechanically. In such an embodiment, the gear box 48 is a first gear box with a first gear ratio attached to a first blade in the first set of cutting blades 6, and the gear box 48 is a second gear box with a second gear ratio attached to a first blade in the second set of cutting blades 8. Thus, when the first set of cutting blades 6 is attached to the housing 4, the motor may rotate at the same rotational speed as when the second set of cutting blades 8 is attached to the housing 4.

In such embodiments, at least one cog of the gear box 48 or the entire gear box 48 is arranged in each of the first and second sets of cutting blades 6, 8. Thus, the gear ratio is changed together with these sets of cutting blades 6, 8.

Fig. 6 shows a method 100 of operating a hand-held trimmer for gardening purposes, such as any of the hand-held trimmers 2 discussed above in connection with fig. 1 a-5. Thus, the handheld shears 2 comprises a housing, an electric motor arranged within the housing, a battery connectable to the electric motor, a first set of cutting blades and a second set of cutting blades, wherein the first set of cutting blades and the second set of cutting blades can be connected to the housing one at a time to be driven by an output shaft of the electric motor. The method 100 comprises the steps of:

-operating 102 a first blade of the first set of cutting blades at a first maximum speed when the first set of cutting blades is connected to the output shaft, and

operating 104 a first blade of the second set of cutting blades at a second maximum speed when the second set of cutting blades is connected to the output shaft.

It should be understood that the foregoing is illustrative of various example embodiments and that the invention is limited only by the claims that follow. Those skilled in the art will recognize that modifications may be made to the exemplary embodiments, and that different features of the exemplary embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended claims.