Shears with mechanical end stops

Abstract

The present invention relates to a portable electric shears (100) comprising: at least one movable blade (106); an electric motor for driving the at least one movable blade (106); and at least one mechanical end stop device (114) for the end of the mechanical travel of the movable blade (106) in at least one direction of movement, characterized in that the portable electric shears (100) further comprises means (130) for detecting contact with the stop device in at least one direction of movement based on the current consumed by the electric motor.

Description

Detailed Description of the Invention

[0001] The present invention relates to a portable power shears with mechanical end stops. The field of the invention is that of portable power shears.

[0002] [Prior Art] Portable power shears include a cutting tool having at least one movable blade and an electric motor for actuating the movable blade. The transition from manual shears to portable power shears has allowed for increased productivity and reduced fatigue for operators using the shears.

[0003] However, power shears are not without their drawbacks. For example, power shears are prone to misadjustments that can change the travel of the movable blade. In extreme cases, misadjustments can even cause the movable blade to go off-track.

[0004] To prevent the movable blade from moving beyond its intended travel range, current shears are fitted with end-of-travel detection means, which typically comprise one or more position sensors, e.g. (Hall-type) magnetic field sensors associated with one or more magnets.

[0005] However, the use of such detection means increases the number of components present in the shears and of course increases the size, complexity and cost of the shears. In addition, the detection means must be precisely positioned and calibrated, thus increasing the complexity of the shears' assembly. Moreover, the detection means are generally prone to misalignment, thereby increasing the maintenance needs of the tool.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to overcome at least one of the above mentioned drawbacks. Another object of the invention is to propose a shears in which the end of travel of the movable blades is detected in a simpler, more cost-effective, less space-consuming and more reliable way.

[0007] [Disclosure of the Invention] The present invention makes it possible to achieve at least one of the above objects by means of a portable electric shears comprising at least one movable blade, an electric motor for driving said at least one movable blade, and at least one mechanical end stop of said movable blade in at least one direction of movement, further comprising end stop detection means as a function of the current consumed by said electric motor in said at least one direction of movement.

[0008] It is therefore proposed that the shears according to the invention detect the position of the end stop of the movable blade as a function of the current consumed by the motor of said shears. Indeed, when the movable blade reaches the position of the mechanical end stop, this causes an increase in the current consumed by the electric motor. By monitoring the value of this current, it is therefore possible to detect the abutment of the blade. As a result, it is not necessary to use a dedicated sensor, such as a magnetic sensor, that is a type of sensor using magnets or the Hall effect, to monitor the position of the movable blade.

[0009] Thus, the construction of the shears is simplified, more cost effective and less bulky. Furthermore, monitoring of the position of the movable blade does not rely on the action of a dedicated sensor, but is more consistent and depends solely on the presence of mechanical end stops and motor current.

[0010] In addition, reducing the number of electronic components required in the shears, especially with respect to moving parts, allows, for example, the use of a single electronic circuit board in the shears, which also allows the avoidance of the use of connecting wires between multiple electrical circuit boards, thereby increasing the reliability of the shears, which in fact may increase the risk of failure, especially by breaking at the contact points between the electronic circuit board and the wires.

[0011] The shears according to the invention may comprise a cutting tool fitted with a single movable blade with a fixed counter blade, or alternatively a cutting tool having two movable blades.

[0012] The electric motor of the shears may be, for example, of the brushless type. The motor is capable of driving at least one blade in a direction corresponding to a closing direction of the cutting tool and a reverse direction corresponding to an opening direction of the cutting tool, typically in sequence.

[0013] According to an embodiment, the at least one mechanical end stop may be located on any component of the shears. The mechanical end stop may be mounted, for example, on the body of the shears or on a fixed backing blade, such that the movable blade contacts said mechanical end stop at the end of its travel.

[0014] Conveniently, at least one mechanical end stop may be provided on said at least one movable blade. Thus, it is possible to fit a mechanical end stop to the shears that does not need to interfere with the structure of the shears, but only with the movable blades. Thus, it is possible to fit each movable blade with a mechanical end stop that is tailored to the movable blade at the time the blades are manufactured.

[0015] According to an embodiment, at least one mechanical end stop device may have a shape that protrudes from the movable blade like a teardrop or protrusion and is provided to abut against a portion of the body of the shears or a portion of the back blade.

[0016] According to an embodiment, at least one movable blade may have a toothed portion for engaging with a gear, and at least one mechanical end stop device may be formed at at least one of the ends of the toothed portion by modifying the tooth profile of the toothed portion.

[0017] Thus, at least one mechanical end stop can be attached directly to the movable blade during manufacture of the movable blade, and no additional components need to be added to the movable blade to attach the mechanical end stop to the movable blade. The modification of the tooth profile may preferably be performed at the position of the endmost tooth near one end of the toothed portion of the movable blade, or even at the position of the penultimate tooth.

[0018] Preferably, but not exclusively, at least one mechanical end stop can be formed by a tooth groove of shallow depth compared to other tooth grooves of the toothed portion. Alternatively, any other tooth profile modification can also be suitable for forming a mechanical end stop. For example, it is also possible to modify the tooth thickness, the tooth height, or even to reduce the gap between two teeth.

[0019] Depending on the embodiment, the shears may be equipped with several mechanical end stops. It is thus possible to detect various travel ends in the shears of the present invention and accordingly reduce the additional sensors that would have had to be used in prior art solutions.

[0020] If the shears comprise a movable blade cooperating with a fixed counter blade, the shears according to the invention may comprise several, in particular two, mechanical end stops for said movable blades, each of which may constitute a mechanical end limit of the range of said movable blade in its direction of movement.

[0021] In the case where the shears comprise two movable blades cooperating with one another, the shears according to the invention may comprise at least one mechanical end stop for each movable blade, in particular two mechanical end stops, each mechanical end stop associated with each movable blade being capable of constituting a mechanical end-of-travel point in the direction of movement of said movable blade.

[0022] According to an embodiment the end stop detection means may be arranged to compare the current consumed by the motor with a predefined threshold. It is thus possible to correlate the value of the current consumed by the electric motor with the abutment of the movable blade against the mechanical end stop, and it is also possible to adjust this current value upwards or downwards, in order to prevent false detection of the mechanical end stop every time the motor current increases, particularly when cutting.

[0023] Advantageously, the shears according to the invention comprise at least one theoretical end stop of at least one movable blade, the position of which is determined by at least one mechanical end stop, - Motor speed, or - Drive duration It is possible to provide a theoretical end-of-travel stop defined as a function of

[0024] In this case, the end stop detection means may be arranged to detect at least one theoretical end stop in at least one direction of movement of the at least one movable blade. It is thus possible to define a theoretical travel end of the at least one movable blade which is different from the mechanical travel end.

[0025] It is therefore possible to have a theoretical end-of-travel stop near the mechanical end of travel, which allows the blade travel to be limited without the need for a mechanical abutment, thereby limiting the excessive wear associated with a mechanical abutment, and further limits wear on the shears components, particularly the motor and the mechanical end stop.

[0026] In particular, for a given direction of movement of the movable blade, at least one theoretical end stop can be defined on the same side as the mechanical end stop.

[0027] Alternatively or additionally, for a given direction of movement of the movable blade, at least one theoretical end stop can be defined opposite the mechanical end stop, so that it is possible to have a theoretical end stop to limit the movement of the blade in the opposite direction to the mechanical end stop, thereby making it possible to limit the movement of the blade in both directions of movement.

[0028] The detection means may comprise a single set of devices arranged to detect both the at least one mechanical end stop and the at least one theoretical end stop.

[0029] Alternatively, the end stop detection means may comprise a first set of devices for detecting at least one mechanical end stop and a second set of devices, different from the first set of devices, for detecting at least one theoretical end stop.

[0030] Depending on the embodiment, the positions of one or all of the theoretical end stops may be recorded into the shears at the factory.

[0031] According to an embodiment, the shears according to the invention may comprise input means for defining the position of at least one theoretical end stop.

[0032] It is thus possible to define and modify the position of the theoretical end stops and thus to customize one or all of the theoretical end stops. For example, it is possible to extend the possible travel of the blades, in particular to compensate for blade wear. Furthermore, it is also possible to reduce the travel of the blades, in order to optimize the wear of the shears, for example when cutting small objects.

[0033] According to an example embodiment, the input means may comprise a communication interface making it possible to define the position of at least one theoretical end stop device digitally, for example as a motor revolution number or as a drive duration, in the form of a digital command transmitted by an external device of computer type and stored in the shears.

[0034] Alternatively, or additionally, the theoretical end stop input means may comprise manual input means for defining the position of the at least one theoretical end stop. The manual input means may for example comprise a user interface or buttons, in particular a control knob, allowing input of the theoretical end stop positions.

[0035] According to an example embodiment, this manual input means may be provided, for example via a user interface including a keypad, control knob, etc., for inputting the number of motor revolutions or drive duration corresponding to the position of the theoretical end stop relative to the mechanical end stop.

[0036] Alternatively, or additionally, manual input means may be provided for inputting the current position of the movable blade as the theoretical end stop position, where the blade is moved to the desired position and, once that position is reached, inputted as the theoretical end stop position, for example by pressing a save button.

[0037] According to an embodiment of the present invention, the shears may be programmed to perform an initialization sequence that includes mechanical abutment of at least one movable blade. Mechanical abutment consists of driving the blade in the direction of travel until it reaches the position of a mechanical end stop.

[0038] This makes it possible to ensure accurate positioning of the blades of the shears according to the invention and, if necessary, accurate detection of the position of the theoretical end stops. This initialization sequence may be performed, for example, every time the shears are powered, or alternatively, at regular intervals, defined, for example, as the number of cuts made or the time elapsed since the last initialization.

[0039] Depending on the embodiment, the shears according to the invention can be equipped with several theoretical end stops. Thus, various theoretical end-of-travel positions of the shears according to the present invention can be detected without the need for mechanical abutments.

[0040] If the shears comprise a movable blade cooperating with a fixed counter blade, the shears according to the invention may comprise several, in particular two, theoretical end stops for said movable blade, each of which may constitute a theoretical end-of-travel point in the direction of movement of the movable blade.

[0041] If the shears comprise two movable blades cooperating with one another, the shears according to the invention may comprise at least one theoretical end stop for each movable blade, in particular two theoretical end stops, each associated with each movable blade being capable of constituting a theoretical end-of-travel point in the direction of movement of said movable blade.

[0042] According to a particular embodiment, the shears according to the invention may comprise a movable blade with a fixed counter blade.

[0043] In this embodiment, the shears according to the invention may comprise two mechanical end stops for the movable blade, each defining a mechanical end of travel in the direction of movement of said movable blade.

[0044] Therefore, it is possible to mechanically limit the movement of the movable blade in each of the two moving directions of the movable blade without using an additional sensor, thereby making it possible to prevent the movable blade from becoming out of position during movement.

[0045] Further in this embodiment, the shears according to the present invention include: - a first mechanical abutment between the movable blade and a first mechanical end stop in one direction of movement, - a second mechanical abutment of the movable blade with a second mechanical end stop in the opposite direction of movement, and - Identifying the set of installed blades between said mechanical end stops as a function of the number of motor revolutions or of the duration of the drive. The device may be programmed to execute an initialization sequence including:

[0046] Thus, the movable blade is first driven in a first direction of movement, preferably in the opening direction of the tool, to reach a mechanical end stop position with a first mechanical end stop, after which the movable blade is driven in the opposite direction to reach a mechanical end stop position with the other mechanical end stop.

[0047] By obtaining information about the number of motor revolutions or the required drive duration to move the movable blade from one mechanical end stop position to another, it is possible to identify which type of blade (or set of blades) is attached to the shears. In fact, the different blade sets that can be attached to the shears are designed to perform different sizes of cuts and therefore different openings. Thus, each set of blades has unique dimensions that allow different blade openings. Thus, the number of motor revolutions or the required drive duration to move the movable blade from one mechanical end stop to another is specific to each set of blades.

[0048] It is therefore possible for the shears to identify each set of blades as a function of the number of motor revolutions or required drive duration required to move the attached movable blade from one mechanical end stop to another. A characteristic, defined as the number of motor revolutions or as the duration of drive, which makes it possible to identify each set of blades, is preferably recorded on the shears at the factory.

[0049] Further in this embodiment, the shears may comprise two theoretical end stops for the movable blade, each defining a theoretical end of travel in at least one direction of movement of said movable blade.

[0050] It is thus possible to limit the movement of a single movable blade between two theoretical end stops, and therefore the travel of the movable blade in both directions of its movement, without the need for mechanical abutments.

[0051] According to a variant of this embodiment, the position of one or each of the two theoretical end stops may vary depending on the set of blades mounted on the shears, and the position of said theoretical end stop specific to each set of blades may preferably be recorded on the shears, for example at the factory.

[0052] Other advantages and characteristics will become apparent upon examination of the detailed description of the in no way limiting embodiments and of the accompanying drawings. [Brief description of the drawings]

[0053] 1a and 1b are partial diagrammatic representations of non-limiting example embodiments of shears according to the present invention. 2a and 2b are partial diagrammatic representations of another non-limiting example embodiment of a shears in accordance with the present invention. 3a and 3b are partial diagrammatic representations of yet another non-limiting example embodiment of a shears in accordance with the present invention. FIG. 4 is a partial diagrammatic representation of another non-limiting example embodiment of a shears in accordance with the present invention. FIG. 5 is a partial diagrammatic representation of another non-limiting example embodiment of a shears in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Of course, the embodiments described herein below are in no way limiting. In particular, if a feature is selected from among the features described herein below, separately from the other features described, and this selection of feature provides a technical advantage or is sufficient to differentiate the invention over the prior art, a variant of the invention comprising only this selected feature can be envisaged. This selection includes at least one, preferably functional feature, without structural details, or with only a part of structural details, if this part alone provides a technical advantage or is sufficient to differentiate the invention over the prior art.

[0055] In the drawings, elements common to several figures have the same reference numbers. 1a and 1b are partial diagrammatic representations showing non-limiting examples of shears according to the present invention. In particular, Figure 1a shows a distal portion of handheld powered shears 100. Figure 1b shows an enlarged view of the components included within box AA of Figure 1a.

[0056] The handheld power shears 100 is fitted with a cutting tool 102 mounted on the distal end of the shears body 104. The cutting tool 102 includes a movable blade 106 with a fixed base blade 108.

[0057] The movable blade 106 is provided at its end facing the shears body 104 with teeth 110 which engage with a gear 112 mounted on the shears body 104. An electric motor (not shown) is provided to drive the gear 112 in both directions of rotation in order to drive the movable blade 106 in both drive directions, i.e. in the opening or closing direction of the movable blade in turn.

[0058] The shears 100 include a mechanical end stop 114 provided on the movable blade 106. The mechanical end stop 114 is provided at one end of the teeth 110 of the movable blade 106.

[0059] 1a and 1b, the movable blade 106 is in a mechanical end stop position, where the mechanical end stop 114 is in contact with the gear 112. The mechanical end stop position of the movable blade 106 in the figures corresponds to the end of mechanical travel of said movable blade 106 in the opening direction of the cutting tool. Thus, when the movable blade 106 is in mechanical abutment, it cannot continue opening further, as the mechanical end stop 114 physically prevents it from rotating in the opening direction and therefore from opening beyond said mechanical end stop 114.

[0060] As shown in more detail in FIG. 1b, in the shears 100, the mechanical end stop 114 is formed by modifying the tooth profile of the toothed portion 110. In particular, the mechanical end stop 114 is formed by a tooth space 116 that is shallower in depth compared to the depth of the other tooth spaces 118 of the toothed portion 110. In other words, the tooth space 116 is higher than the other tooth spaces of the toothed portion. A height difference 120 between the tooth space 116 that forms the mechanical end stop 114 and the other tooth spaces 118 is indicated by root circles 122 and 124 of both tooth spaces, respectively. The modified tooth profile that forms the mechanical end stop 114 has a side surface 126 that is shaped to at least partially receive the tooth surface of the gear 112.

[0061] In the illustrated example, it is the endmost tooth gap of the toothed portion 110 that forms the mechanical end stop 114. Alternatively, another tooth gap of the toothed portion 110, such as the second end tooth gap in the opening direction of the toothed portion, may be used as the mechanical end stop.

[0062] The shears 100 further includes a mechanical end stop detection means 130. The mechanical end stop detection means 130 detects the current i consumed by the motor. M is a given threshold i S In order to detect the moment when the current i consumed by the electric motor to move the movable blade 106 becomes larger, MThe motor is responsible for monitoring the state of the movable blade 106. In fact, when the movable blade 106 is in a mechanical abutment state, the blade is prevented from opening further, so that the motor consumes more current to continue moving the blade in the opening direction. Thus, such an increase in the current consumed by the motor is a direct indication that the movable blade 106 is in a mechanical abutment state in the opening direction.

[0063] In the illustrated example, the mechanical end stop detection means 130 includes: - current consumed by the electric motor i M in real time or at least at a frequency sufficiently high relative to the speed of movement of the movable blade 106; - the current i measured by the first module 132 M The value of i S a second module 134 for comparing with a third optional module 136 making it possible to bring about the cessation of the drive of the movable blade 106 by the motor, with or without subsequent drive of the movable blade 106 in the reverse direction; It is equipped with:

[0064] Each of the modules 132, 134, and 136 may be fabricated from at least one digital component or at least one analog component, or from any combination of digital and analog components.

[0065] Each of the modules 132-136 may be independent. Alternatively, at least two of the modules 132-136 may be integrated. For example, the modules 132-136 may be integrated into a single electronic component, such as an electronic chip. Each of the modules 132-136 may be mounted on an existing circuit board within the shears that provides a separate function, or may be mounted on a dedicated circuit board.

[0066] 2a and 2b are partial diagrammatic representations showing another non-limiting example of a shear according to the present invention. The shears 200 of FIGS. 2a and 2b shown in FIGS. 2a and 2b includes all of the components of the shears 100 of FIGS. 1a and 1b. Additionally, the handheld power shears 200 includes a mechanical end stop 202 disposed on the movable blade 106 that acts as a mechanical end stop for the movable blade 106 in the closing orientation of the movable blade 106 .

[0067] Each of the mechanical end stops 114 and 202 is located at one end of the teeth 110 of the movable blade 106. Each of the mechanical end stops 114 and 202 thus constitutes a mechanical end-of-travel limit in the direction of movement of the movable blade.

[0068] 2a, the movable blade 106 is located at the end of its mechanical travel in the opening direction of the cutting tool 102. In this first mechanical end stop position, the mechanical end stop 114 is in contact with the gear 112.

[0069] 2b, the movable blade 106 is at the end of its mechanical travel in the closing direction of the cutting tool 102. In this second mechanical end stop position, the mechanical end stop 202 contacts the gear 112.

[0070] The second mechanical end stop 202 has a structure similar to that of the end stop 114. Specifically, like the end stop 114, the mechanical end stop 202 is formed by a modification of the tooth profile of the toothed portion 110. More specifically, the mechanical end stop 202 is formed by a tooth gap of a shallow depth compared to the depth of the other tooth gaps 118 of the toothed portion 110.

[0071] In the illustrated example, the mechanical end stops 114 and 202 are each formed by an endmost tooth gap of the toothed portion 110 at each end of the toothed portion 110. Alternatively, at least one of the mechanical end stops 114 and 202 could be formed by another tooth gap of a toothed portion.

[0072] In the shears 200, the mechanical end stop detection means 130 of the shears 200 is configured to detect mechanical abutment in both drive directions of the movable blade 106. Indeed, upon mechanical abutment, regardless of the direction of movement of the movable blade 106, the mechanical end stop 114, 202 will block the movement of the movable blade 106 when it reaches the position of the mechanical end stop, causing the motor to consume more current to continue moving the movable blade. This increase can thus be detected by the mechanical end stop detection means 130.

[0073] 3a and 3b are partial diagrammatic representations of yet another non-limiting example embodiment of a shears according to the present invention. The handheld power shears 300 shown in Figures 3a and 3b includes all of the components of the shears 200 shown in Figures 2a and 2b. The shears 300 further include a theoretical end stop detection means 330 .

[0074] In practice, the shears 300 may be provided with one or two theoretical end stops. In the illustrated example, the shears 300 is provided with two theoretical end stops.

[0075] Each theoretical end stop serves to limit the travel of the movable blade 106 in at least one direction of movement of the movable blade 106. Unlike the mechanical end stops 114 or 202, the theoretical end stops do not physically prevent the rotation of the blade 106. However, the theoretical end stops, and specifically their detection, make it possible to stop the motor from driving the movable blade 106 even if the movable blade is not at the position of a mechanical end stop.

[0076] In the illustrated example, each theoretical end stop position is determined by one mechanical end stop 114 or 202 and the number of motor revolutions T required for the motor to move the movable blade 106 from the mechanical end stop position to the theoretical end stop position. M It is defined as a function of

[0077] In this example, the motor revolution speeds T of two theoretical end stops are calculated for example for the position of the mechanical end stop 114. S1 and T S2 3a, the movable blade 106 is at its theoretical end of travel in the opening direction of the cutting tool 102, and thus at its theoretical end stop position. This first theoretical end stop position is located just before the mechanical end stop position 114 in the travel of the movable blade 106 in the opening direction of the cutting tool 102. It should be noted that in the theoretical end of travel position in the opening direction as shown in FIG. 3a, the cutting tool 102 is slightly more closed than when it is at its mechanical end of travel position in the opening direction as shown in FIG. 2a. In FIG. 3b, the movable blade 106 is at its theoretical end of travel in the closing direction of the cutting tool 102, and thus at its theoretical end stop position. This second theoretical end stop position is located just before the mechanical end stop position 202 in the travel of the movable blade 106 in the closing direction of the cutting tool 202. Note that in the theoretical end-of-travel position in the closing direction as shown in FIG. 3b, the cutting tool 102 is slightly more open than when it is in the mechanical end-of-travel position in the closing direction as shown in FIG. 2b.

[0078] In the illustrated example, the theoretical end stop detection means 330 includes: the current number of motor revolutions T corresponding to the current position of the movable knife from the mechanical end stop position of the movable knife in the opening direction of the cutting tool 102, preferably from the mechanical end stop position 114; M A first module 332, also called a register of the movable blade position, is provided for maintaining and updating the position of the movable blade (to maintain this register, the first direction of rotation of the motor is positive and the opposite direction of rotation is negative, and the mechanical end stops are T M = 0. For example, the direction of rotation that drives the blade in the closing direction of the cutting tool is set to be positive, so that T M increases as the movable blade 106 closes, and the opening direction of the cutting tool is made negative, so that T M becomes smaller as the movable blade 106 closes),

[0079] the number of motor revolutions T in a register held by the first module 332 M The theoretical end stop position T S1 and T S2 a second module 334 for comparing with - Rotation speed T M but, ●T S1 (which means that the movable blade has reached a theoretical end stop, e.g. a theoretical end stop in the opening direction), ●T S2 (this means that the movable blade has reached the other theoretical end stop, e.g. the theoretical end stop in the blade closing direction) a third module 336, which makes it possible to bring about the cessation of the drive of the movable blade 106 by the motor, with or without the addition of a drive of the movable blade 106 in the opposite direction; It is equipped with:

[0080] Each of the modules 332, 334 and 336 may be produced using at least one digital component or at least one analog component, or any combination of digital and analog components.

[0081] The modules 332-336 may be independent of each other. Alternatively, at least two of the modules 332-336 may be combined. For example, the modules 332-336 may be integrated into a single electronic component, such as an electronic chip. Each of the modules 332-336 may be mounted on an existing circuit board within the shears that provides other functions, or may be mounted on a dedicated circuit board.

[0082] According to a variant not shown, the position of each theoretical end stop is defined as a function of a single mechanical end stop and the duration of the drive required by the motor to move the movable blade from the position of said mechanical end stop to the position of said theoretical end stop with a uniform speed. The operation of the theoretical end stop detection means of this variant is similar to that of the theoretical end stop detection means described above with reference to figures 3a and 3b.

[0083] According to another variant, not shown, the positions of the first and second theoretical end stops are defined as a function of the first and second mechanical end stops and of the motor revolutions or of the duration of the drive. The operation of the theoretical end stop detection means of this variant differs from that described above with reference to figures 3a and 3b in that two different blade position registers are kept by the first module and that the second module compares the values ​​of the positions of the individual theoretical end stops with the current values ​​of the corresponding registers.

[0084] FIG. 4 is a partial diagrammatic representation of another non-limiting example of a shear according to the present invention. The handheld power shears 400 of FIG. 4 differs from the shears 300 of FIGS. 3a and 3b in that it includes one mechanical end stop 402.

[0085] Additionally, unlike shears 300, the mechanical end stop 402 of shears 400 is formed on the body of shears 400 rather than on the moving blade. Specifically, the mechanical end stop 402 is formed as a teardrop, and generally any shape, protruding from the body 104 of the shears, and is fixed and integral to said body 104 of the shears 400 against which the moving blade 106 abuts when opening.

[0086] 4, the movable blade 106 is in the mechanical end stop position. In this position, the mechanical end stop 402 contacts the portion of the blade that is included between the axis of rotation of the blade and the teeth portion 110.

[0087] Apart from the mechanical end stop 402, the shears 400, like the shears 300, also have two theoretical end stops which can be detected by the theoretical end stop detection means 330. These theoretical end stops are defined as the number of motor revolutions relative to the position where the blade 106 is in mechanical contact with the mechanical end stop 402. These two theoretical end stops thus allow the blade 106 to move in the opening and closing directions of the cutting tool 102. 106 It is possible to limit the range of movement of the

[0088] According to an alternative embodiment not shown, the shears 400 may be provided with a single theoretical end stop defined in terms of the mechanical end stop 402 to form a theoretical limit of travel of the movable blade 106 in the closing direction of the cutting tool 102.

[0089] According to another variant not shown, a mechanical end stop 402 can also be provided to physically limit the movement of the movable blade 106 in the closing direction of the cutting tool 102 .

[0090] FIG. 5 is a partial diagrammatic representation of another non-limiting example of a shear according to the present invention. The portable power shears 500 of FIG. 5 includes all of the components of the shears 400 of FIG. The shears 500 further include a second mechanical end stop 502 . In the illustrated example, and without limitation, the second mechanical end stop 502 is in the form of a teardrop protruding from the body 104 . The mechanical end stop 502 physically limits the movement of the movable blade 106 in the closing direction of the cutting tool 102 .

[0091] The movable blade 106 as shown in FIG. 5 is held in place by an end stop 502 at a mechanical end stop. A shears 500 as shown in FIG. 5 has two theoretical end stops. According to an alternative not shown, the shears 500 may be provided with a single theoretical end stop.

[0092] According to another variant, not shown, it is also possible that the shears 300, 400 and 500 of figures 3a-3b, 4 and 5 are not provided with a theoretical end stop device.

[0093] Of course, the invention is not limited to the examples detailed above.

Claims

1. at least one movable blade (106); - an electric motor for driving said at least one movable blade (106); at least one mechanical end-of-travel stop (114; 202; 402; 502) for said movable blade (106) in at least one direction of movement; Equipped with 10. A portable electric shears (100; 200; 300; 400; 500) further comprising end stop detection means in said at least one direction of movement as a function of the current consumed by said electric motor.

2. 2. The shears (100; 200; 300) according to claim 1, characterized in that at least one mechanical end stop (114; 202) is provided on said at least one movable blade (106).

3. 3. The shears (100; 200; 300) according to claim 2, characterized in that the at least one movable blade (106) comprises a toothed portion (110) engaging with a gear (112), and the at least one mechanical end stop device (114; 202) is formed by a modification of the tooth profile at least on one of the ends of the toothed portion (110).

4. Shears (200; 300; 500) according to any one of claims 1 to 3, characterised in that the shears comprises several mechanical end stops (114, 202; 402, 502).

5. The shears (100; 200; 300; 400; 500) according to any one of claims 1 to 4, characterized in that the end stop detection means (130) are arranged to compare the current consumed by the motor with a predefined threshold value.

6. at least one theoretical end-of-travel stop of at least one movable blade (106), the position of which is determined by at least one mechanical end stop; - Motor speed, or - Drive duration a theoretical end-of-travel stop defined as a function of the end stop detection means (330) is further configured to detect at least one theoretical end stop in at least one direction of movement of the at least one movable blade (106); A shears (300; 400; 500) according to any one of claims 1 to 5, characterized in that

7. 7. Shears (300; 400; 500) according to claim 6, characterized in that it comprises input means for defining the position of at least one theoretical end stop.

8. 8. Shears (300; 400; 500) according to claim 6 or 7, characterized in that it comprises manual input means for defining the position of at least one theoretical end stop.

9. A shears (300; 400; 500) according to any one of the preceding claims, characterized in that it is programmed to carry out an initialization sequence including mechanical abutment of at least one movable blade (106).

10. Shears (300; 400; 500) according to any one of claims 6 to 9, characterised in that the shears are equipped with several theoretical end stops.

11. A shears (100; 200; 300; 400; 500) according to any one of the preceding claims, characterized in that it comprises a moving blade (106) with a fixed counter blade (108).

12. The shears (200; 300; 500) according to any one of claims 1 to 11, characterized in that it comprises two mechanical end stops (114, 202; 402, 502) for the movable blade (106), each defining a mechanical end of travel in the direction of movement of the movable blade (106).

13. The initialization sequence is a first mechanical abutment of the movable blade (106) with a first mechanical end stop device (114, 202; 402, 502) in one direction of movement, a second mechanical abutment of the movable blade (106) with a second mechanical end stop device (114, 202; 402, 502) in the opposite direction of movement, and - Identifying the set of installed blades between said mechanical end stops as a function of the number of motor revolutions or of the duration of the drive.

13. A shearser (200; 300; 500) according to any one of claims 9 and 12, characterised in that it comprises

14. The shears (200; 300; 500) according to any one of claims 6 and 11 to 13, characterized in that it comprises two theoretical end stops for the movable blades (106), each defining a theoretical end of travel in at least one direction of movement of the movable blades (106).

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