SHEARS WITH A MECHANICAL END STOP

Abstract

Portable motorized electric shears include at least one mobile blade, an electric motor for driving the at least one mobile blade, and at least one mechanical end stop for the mechanical end of travel of the mobile blade in at least one direction of travel; a structure for detecting abutment against the stop, in the at least one direction of travel, on the basis of a current drawn by the electric motor.

Claims

1. A portable electric motorized shears comprising: at least one movable blade; an electric motor for driving said at least one movable blade; and at least one mechanical end-of-travel end stop of said movable blade in at least one direction of displacement; and an end stop detection means in said at least one direction of displacement, as a function of a current consumed by said electric motor.

2. The shears according to claim 1, characterized in that at least one mechanical end stop is provided on said at least one movable blade.

3. The shears according to claim 2, characterized in that said at least one movable blade comprises a toothed section engaging with a toothed wheel, at least one mechanical end stop being formed by a modification of the toothing profile of said toothed section, at at least one of its ends.

4. The shears according to claim 1, characterized in that the shears comprise several mechanical end stops.

5. The shears according to claim 1, characterized in that the end stop detection means is configured to compare the current consumed by the motor with a predefined threshold.

6. The shears according to claim 1, characterized in that they comprise at least one theoretical end-of-travel end stop of at least one movable blade, the position of which is defined as a function of at least one mechanical end stop and: of a number of motor revolutions or of a duration of drive; the end stop detection means also being configured to detect at least one theoretical end stop in at least one direction of displacement of at least one movable blade.

7. The shears according to claim 6, characterized in that they comprise an input means for defining the position of at least one theoretical end stop.

8. The shears according to claim 6, characterized in that they comprise a manual input means for defining the position of at least one theoretical end stop.

9. The shears according to claim 1, characterized in that they are programmed to implement an initialization sequence comprising a mechanical abutment of at least one movable blade.

10. The shears according to claim 1, characterized in that the shears comprise several theoretical end stops.

11. Shears according to claim 1, characterized in that they comprise a movable blade associated with a fixed counter-blade.

12. The shears according to claim 1, characterized in that they comprise two mechanical end stops for the movable blade, each defining a mechanical end-of-travel in a direction of displacement of said movable blade.

13. The shears according to claim 9, characterized in that the initialization sequence comprises: a first mechanical abutment of the movable blade with a first mechanical end stop, in one direction of displacement, a second mechanical abutment of the movable blade with a second mechanical end stop, in the opposite direction of displacement, and determining a fitted blade kit as a function of a number of motor revolutions, or of a duration of drive, between said mechanical end stops.

14. The shears according to claim 6, characterized in that they comprise two theoretical end stops for the movable blade, each defining a theoretical end-of-travel in at least one direction of displacement of said movable blade.

Description

DESCRIPTION OF THE FIGURES AND EMBODIMENTS

[0072] Other advantages and characteristics will become apparent on examination of the detailed description of an embodiment that is in no way limitative, and of the attached drawings, in which

[0073] FIGS. 1a and 1b are partial diagrammatic representations of a non-limitative embodiment example of shears according to the invention;

[0074] FIGS. 2a and 2b are partial diagrammatic representations of another non-limitative embodiment example of shears according to the invention;

[0075] FIGS. 3a and 3b are partial diagrammatic representations of yet another non-limitative embodiment example of shears according to the invention;

[0076] FIG. 4 is a partial diagrammatic representation of another non-limitative embodiment example of shears according to the invention; and

[0077] FIG. 5 is a partial diagrammatic representation of another non-limitative embodiment example of shears according to the invention.

[0078] It is well understood that the embodiments that will be described hereinafter are in no way limitative. In particular, variants of the invention may be envisaged comprising only a selection of the characteristics described hereinafter, in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of the prior art. This selection comprises at least one, preferably functional, characteristic without structural details, or with only a part of the structural details if this part alone is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of the prior art.

[0079] In the figures, elements common to several figures retain the same reference.

[0080] FIGS. 1a and 1b are partial diagrammatic representations of a non-limitative example of shears according to the invention.

[0081] In particular, FIG. 1a shows a distal part of portable electric motorized shears 100. FIG. 1b shows, in an enlarged view, elements comprised within the box A-A in FIG. 1a.

[0082] The portable electric motorized shears 100 are fitted with a cutting tool 102 mounted on a distal end of the body 104 of the shears. The cutting tool 102 comprises a movable blade 106 associated with a fixed counter-blade 108.

[0083] The movable blade 106 comprises, at its end located on the side of the body 104 of the shears, a toothed section 110 engaged with a toothed wheel 112 placed on the body 104 of the shears. An electric motor (not shown) is provided to drive the toothed wheel 112 in both directions of rotation so as to drive the movable blade 106, in rotation, in both directions of drive, namely in the opening direction or in the closing direction of the movable blade.

[0084] The shears 100 comprise a mechanical end stop 114, provided on the movable blade 106. This mechanical end stop 114 is provided at one end of the toothed section 110 of the movable blade 106.

[0085] The movable blade 106 as shown in FIGS. 1a and 1b is in a mechanical end stop position, the mechanical end stop 114 being in contact with the toothed wheel 112. The mechanical end stop position of the movable blade 106 shown corresponds to the mechanical end-of-travel position of said movable blade 106 in the opening direction of the cutting tool. Thus, when the movable blade 106 is in mechanical abutment, it can no longer continue to open, because the mechanical end stop 114 physically prevents its rotation in the opening direction and therefore its opening beyond said mechanical end stop 114.

[0086] As shown in greater detail in FIG. 1b, in the shears 100, the mechanical end stop 114 is formed by a modification of the toothing profile of the toothed section 110. In particular, the mechanical end stop 114 is formed by a gullet 116 the depth of which is reduced compared with the depth of the other gullets 118 of the toothed section 110. In other words, the gullet 116 is higher than the other gullets of the toothed section. The height difference 120 between the gullet 116 forming the mechanical end stop 114 and the other gullets 118 is indicated by their respective root circles 122 and 124. The modified toothing profile forming the mechanical end stop 114 comprises a flank 126 the shape of which is provided to receive, at least partially, the tooth flank of the toothed wheel 112.

[0087] In the example shown, it is the last gullet of the toothed section 110 that forms the mechanical end stop 114. Alternatively, another gullet of the toothed section 110 can be used as mechanical end stop, such as for example the penultimate gullet of the toothed section in the opening direction.

[0088] The shears 100 also comprise a mechanical end stop detection means 130. This mechanical end stop detection means 130 is tasked with monitoring the current i.sub.M consumed by the electric motor for actuating the movable blade 106, in order to detect the moment at which the current consumed by the motor becomes greater than a predetermined threshold i.sub.S. Indeed, when the movable blade 106 is in mechanical abutment, this prevents the blade opening further, so that the motor consumes more current in an attempt to continue to displace it in the opening direction. This increase in the current consumed by the motor therefore directly indicates that the movable blade 106 is in mechanical abutment, in the opening direction.

[0089] In the example shown, the mechanical end stop detection means 130 comprises: [0090] a first module 132 measuring the current i.sub.M consumed by the electric motor, in real time, or at least at a sufficiently high frequency with respect to the speed of displacement of the movable blade 106; [0091] a second module 134 for comparing the value of the current i.sub.M measured by the first module 132 with the threshold i.sub.S; and [0092] a third, optional, module 136, making it possible to trigger cessation of the drive of the movable blade 106 by the motor, followed or not by a driving of the movable blade 106 in the reverse direction.

[0093] Each of the modules 132, 134 and 136 can be produced with at least one digital component or at least one analogue component, or with any combination of digital component(s) and analogue component(s).

[0094] Each of the modules 132-136 can be independent. Alternatively, at least two of the modules 132-136 can be combined. For example, the modules 132-136 can be integrated in a single electronic component, such as an electronic chip for example.

[0095] Each of the modules 132-136 can be placed on an existing circuit board in the shears providing another function, or on a dedicated circuit board.

[0096] FIGS. 2a and 2b are partial diagrammatic representations of another non-limitative example of shears according to the invention.

[0097] The shears 200 in FIGS. 2a and 2b, shown in FIGS. 2a and 2b, comprise all the elements of the shears 100 in FIGS. 1a and 1b.

[0098] In addition, the portable electric motorized shears 200 include a second mechanical end stop 202 provided on the movable blade 106, and acting as mechanical end stop for the movable blade 106 in the closing direction of the movable blade 106.

[0099] Each mechanical end stop 114 and 202 is placed at one end of the toothed section 110 of the movable blade 106. Each mechanical end stop 114 and 202 thus constitutes a mechanical end-of-travel limit in a direction of displacement of the movable blade.

[0100] In FIG. 2a, the movable blade 106 is at the mechanical end-of-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 toothed wheel 112.

[0101] In FIG. 2b, the movable blade 106 is at the mechanical end-of-travel in the closing direction of the cutting tool 102. In this second mechanical end stop position, the mechanical end stop 202 is in contact with the toothed wheel 112.

[0102] The second mechanical end stop 202 has an architecture similar to that of the end stop 114. In particular, as for the end stop 114, the mechanical end stop 202 is formed by a modification of the toothing profile of the toothed section 110. More particularly, the mechanical end stop 202 is formed by a gullet the depth of which is reduced compared with the depth of the other gullets 118 of the toothed section 110.

[0103] In the example shown, each mechanical end stop 114 and 202 is formed by the last gullet of the toothed section 110 at each of the ends of the toothed section 110. Alternatively, at least one of the mechanical end stops 114 and 202 can be formed by another gullet of the toothed section.

[0104] In the shears 200, the mechanical end stop detection means 130 of the shears 200 is configured to detect the mechanical abutment in both directions of drive of the movable blade 106. Indeed, during a mechanical abutment, regardless of the direction of displacement of the movable blade 106, a mechanical end stop 114, 202 prevents the displacement of the movable blade 106 when the latter comes into a mechanical end stop position, so that the motor consumes more current in an attempt to continue to displace it. This increase can thus be detected by the mechanical end stop detection means 130.

[0105] FIGS. 3a and 3b are partial diagrammatic representations of yet another non-limitative embodiment example of shears according to the invention.

[0106] The portable electric motorized shears 300 shown in FIGS. 3a and 3b comprise all the elements of the shears 200 shown in FIGS. 2a and 2b.

[0107] The shears 300 also comprise a theoretical end stop detection means 330.

[0108] Indeed, the shears 300 can be provided with one or two theoretical end stops. In the example shown, the shears 300 are provided with two theoretical end stops.

[0109] Each theoretical end stop has the function of restricting the travel of the movable blade 106, in at least one of its directions of displacement. Unlike a mechanical end stop 114 or 202, a theoretical end stop does not physically prevent the rotation of the blade 106. However, a theoretical end stop, and in particular its detection, makes it possible to stop the drive of the movable blade 106 by the motor, without the movable blade being in a mechanical end stop position.

[0110] In the example shown, the position of each theoretical end stop is defined as a function of a single mechanical end stop 114 or 202 and of a number of motor revolutions T.sub.M required for the motor to displace the movable blade 106 from the position of said mechanical end stop to the position of said theoretical end stop.

[0111] In this example, the positions in motor revolutions T.sub.S1 and T.sub.S2 of the two theoretical end stops are pre-recorded in the shears 300, for example with respect to the position of the mechanical end stop 114. In FIG. 3a, the movable blade 106 is at theoretical end-of-travel, and therefore in a theoretical end stop position, in the opening direction of the cutting tool 102. This first theoretical end stop position is situated just before the mechanical end stop position 114 in the displacement travel of the movable blade 106 in the opening direction of the cutting tool 102. It will 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 less open than in the mechanical end-of-travel position in the opening direction as shown in FIG. 2a. In FIG. 3b, the movable blade 106 is at theoretical end-of-travel, and therefore in a theoretical end stop position, in the closing direction of the cutting tool 102. This second theoretical end stop position is situated before the mechanical end stop position 202 in the displacement travel of the movable blade 106 in the closing direction of the cutting tool 202. It will be noted that in the theoretical end-of-travel position in the closing direction as shown in FIG. 3b, the cutting tool 102 is slightly less closed than in the mechanical end-of-travel position in the closing direction as shown in FIG. 2b.

[0112] In the example shown, the theoretical end stop detection means 330 comprises: [0113] a first module 332 provided to keep and update a current motor revolution number T.sub.M, also called register of the position of the movable blade, corresponding to the current position of the movable blade from a mechanical end stop position of the movable blade, preferably from the mechanical end stop position 114 in the opening direction of the cutting tool 102. In order to maintain this register, a first direction of rotation of the motor is assigned as positive and the reverse direction of rotation is assigned as negative, and at the mechanical end stop position T.sub.M=0. For example, the direction of rotation driving the blade in the closing direction of the cutting tool is assigned as positive, so that T.sub.M increases as the movable blade 106 closes, and the opening direction of the cutting tool is assigned as negative, so that T.sub.M reduces as the movable blade 106 closes; [0114] a second module 334 for comparing the value of the number of motor revolutions T.sub.M in the register kept by the first module 332 with the positions T.sub.S1 and T.sub.S2 of the theoretical end stops expressed in motor revolutions; and [0115] a third module 336, making it possible to trigger cessation of the drive of the movable blade 106 by the motor, followed or not by a driving of the movable blade 106 in the reverse direction, when the number of revolutions T.sub.M is equal: [0116] to T.sub.S1: this means that the movable blade has reached a theoretical end stop, for example a theoretical end stop in the opening direction; [0117] to T.sub.S2: this means that the movable blade has reached the other theoretical end stop, for example the theoretical end stop in the closing direction of the blade.

[0118] Each of the modules 332, 334 and 336 can be produced with at least one digital component or at least one analogue component, or with any combination of digital component(s) and analogue component(s).

[0119] Each of the modules 332-336 can be independent. Alternatively at least two of the modules 332-336 can be combined. For example, the modules 332-336 can be integrated in a single electronic component, such as an electronic chip.

[0120] Each of the modules 332-336 can be placed on an existing circuit board in the shears providing other functions, or on a dedicated circuit board.

[0121] According to a variant that is not shown, the position of each theoretical end stop is defined as a function of a single mechanical end stop and of a duration of drive required for the motor to displace the movable blade at constant speed from the position of said mechanical end stop to the position of said theoretical end stop. The operation of the theoretical end stop detection means of this variant is similar to the operation of the theoretical end stop detection means described above with respect to FIGS. 3a and 3b.

[0122] According to another variant that is not shown, the positions of a first and a second theoretical end stop are defined as a function of a first and a second mechanical end stop and of a number of motor revolutions, or of a duration of drive. The operation of the theoretical end stop detection means of this variant differs from the operation of the theoretical end stop detection means described above with respect to FIGS. 3a and 3b in that two different blade position registers are kept by the first module, and in that the second module compares the values of the positions of each theoretical end stop with the current value in the corresponding register.

[0123] FIG. 4 is a partial diagrammatic representation of another non-limitative example of shears according to the invention.

[0124] The portable electric motorized shears 400 in FIG. 4 differ from the shears 300 in FIGS. 3a and 3b, in that they comprise a single mechanical end stop 402.

[0125] In addition, unlike the shears 300, the mechanical end stop 402 of the shears 400 is not formed on the movable blade but on the body of the shears 400. In particular, the mechanical end stop 402 is formed by a tear drop, and in general terms any shape, projecting from the body 104 of the shears, fixed and integral with said body 104 of the shears 400, against which the movable blade 106 comes into abutment when it is opening.

[0126] The movable blade 106 as shown in FIG. 4 is in a mechanical end stop position. In this position, the mechanical end stop 402 is in contact with a part of the blade comprised between the axis of rotation of the blade and its toothed section 110.

[0127] Apart from the mechanical end stop 402, the shears 400 comprise two theoretical end stops capable of being detected by the theoretical end stop detection means 330, like the shears 300. These theoretical end stops are defined as a number of motor revolutions, with respect to the position of mechanical abutment of the blade 106 with the mechanical end stop 402. These two theoretical end stops thus make it possible to restrict the displacement travel of the movable blade 406 in the direction of opening and of closing of the cutting tool 102.

[0128] According to an embodiment variant that is not shown, the shears 400 can comprise a single theoretical end stop defined with respect to the mechanical end stop 402, so as to form a theoretical displacement limit of the movable blade 106 in the closing direction of the cutting tool 102.

[0129] According to another variant that is not shown, the mechanical end stop 402 can be placed so as to physically restrict the displacement of the movable blade 106 in the closing direction of the cutting tool 102.

[0130] FIG. 5 is a partial diagrammatic representation of another non-limitative example of shears according to the invention.

[0131] The portable electric motorized shears 500 in FIG. 5 comprise all the elements of the shears 400 in FIG. 4.

[0132] The shears 500 also comprise a second mechanical end stop 502.

[0133] In the example shown, and non-limitatively, the second mechanical end stop 502 is in the form of a tear drop projecting from the body 104.

[0134] This mechanical end stop 502 physically restricts the displacement of the movable blade 106 in the closing direction of the cutting tool 102.

[0135] The movable blade 106 as shown in FIG. 5 is in a mechanical end stop position with the end stop 502.

[0136] The shears 500 as shown in FIG. 5 comprise two theoretical end stops.

[0137] According to an alternative that is not shown, the shears 500 can comprise a single theoretical end stop.

[0138] According to other variants that are not shown, it is possible for the shears 300, 400 and 500 in FIGS. 3a-3b, 4 and 5 not to have a theoretical end stop.

[0139] Of course, the invention is not limited to the examples detailed above.