Power tool and its manufacturing process

Abstract

The invention relates to a portable electric tool (10) comprising: - an at least partially electrically insulating body (6), comprising: - an actuator, - a transmission connecting the actuator to a machining member (4) - at least one electrical contact surface, arranged to at least partially surround the body (6) and to be grasped by the user, said portable electric tool (10) being arranged to comprise a safety system for a user; the electrical contact surface comprises at least two electrical contact areas (50) which are distinct and separate, and the portable electric tool (10) comprises a connecting element (7) made of electrically conductive material inside the body (6) of the portable electric tool (10) and arranged to be in electrical contact with each electrical contact area (50), in order to electrically connect the electrical contact areas (50) together. Figure to be published with the abstract: Fig. 1

Description

Title of the invention: Portable electric tool and its manufacturing method Technical field

[0001] The present invention relates to a power tool, in particular a power pruning shear arranged to comprise a safety system requiring that the movable blade and / or the fixed blade be made at least partly of electrically conductive material. The present invention also relates to a method of manufacturing such a power tool. State of the art

[0002] In the context of the present invention, the expression "power tool" means an electric or electrically powered tool. The tool may be electrically powered by a self-contained power source. During its use, it is carried by a limb of the user, for example by his hand. In particular, the same limb that carries such a tool also allows it to be controlled, for example by means of a trigger. A power tool does not have a stationary position during its use, because the user moves it, for example to machine a new object or to better machine the same object. In other words, a power tool is not stationary, that is to say it does not always occupy the same position.It is therefore clear in light of this definition that a machine such as a stationary saw, for example a table circular saw or a bench shear, does not fall within the definition of a power tool given in this context.

[0003] The power source of such a power tool may be, for example, a battery or a battery pack. In one case, the source is a separate part of the tool. In particular, the user can carry the tool with one hand and simultaneously carry the power source on him, for example using a backpack, a harness or a belt. In another case, the power source of such a power tool is in the power tool.

[0004] A power tool comprises an actuator, for example a motor, for transmitting a force to an external object on which the tool acts.

[0005] A pruning shears, shears, pliers, presses, a portable chainsaw, a portable circular saw, a portable jigsaw, a planer, a crimper, a router, etc. for agricultural, viticultural, arboricultural, industrial, craft, textile, food, medical, etc. applications are non-limiting examples of portable electric tools according to the invention.

[0006] A power tool comprises a machining member and a support member for this object. The machining member allows an object to be machined and comes into direct contact with this object. It is movable during the machining of the object and actuated by the actuator of the power tool.

[0007] In the context of the present invention, the word "machine" indicates any operation carried out on the object which allows it to be transformed, for example to cut, press, slice, plane etc.

[0008] The support member supports the object during its machining and is generally fixed during the machining of the object. In general, the support member is not actuated by the actuator of the power tool. Its presence is necessary to carry out this machining. The support member is also in direct contact with this object during its machining. In certain cases, the support member is also mobile and / or actuated by the actuator of the power tool.

[0009] In the case where the power tool is a pruning shear, its movable blade is the machining member, because it allows an object such as a branch to be cut, and the counter-blade is the support member, because it supports the branch during its cutting.

[0010] In the case where the portable power tool is a circular saw, its rotating blade is the machining member, because it allows an object such as a piece of wood to be cut, and the plate comprising the passage for the blade and on which the object rests during cutting is the support member.

[0011] In the case where the power tool is a plane, its blade is the machining member, because it allows an object such as a piece of wood to be cut, and the plate on which the object rests during cutting is the support member.

[0012] In the case where the power tool is a portable chainsaw, its rotating chain is the machining member, because it allows an object to be cut, and the chain guide of the portable chainsaw around which the rotating chain moves is the support member.

[0013] These types of tools have become increasingly efficient and are able to generate a force of several kilo-Newtons. However, this efficiency has significantly increased the number of occupational accidents caused by such tools. The need for safety in relation to the movement of the moving blade of these tools has therefore increased rapidly.

[0014] Various solutions in the state of the art attempt to meet this need.

[0015] In particular, several security systems in the state of the art require that the machining member and / or the support member is / are made at least partly of electrically conductive material: in fact, when a hand (or a limb, or in general a portion of the body) of the user touches the machining member and / or the support member, and in particular its / their portion of electrically conductive material, These systems are arranged to modify the speed of the actuator, for example to reduce or cancel it, and possibly trigger an alarm (audible and / or visual). In most cases, an electrical circuit is closed via the hand (or in general the body) of the user when he touches the machining member and / or the support member, and in particular its / their portion made of electrically conductive material: this closure is detected for example via a measurement of an impedance.

[0016] In other words, some power tools include: - an at least partially electrically insulating body, comprising: - an actuator, - a transmission connecting the actuator to a machining member, so as to allow movement of the machining member relative to a support member, - the machining member and / or the support member being made at least partly of electrically conductive material - at least one electrical contact surface, arranged to at least partially surround the body and to be grasped by the user.

[0017] These known portable power tools also comprise a safety system for a user, this safety system being arranged to measure an impedance between the electrical contact surface and the machining member and / or the support member, and to reduce or cancel the speed of the actuator on the basis of this impedance measurement in order to protect the user.

[0018] A non-limiting example of such a security system is for example described in document EP4137274 in the name of the applicant.

[0019] However, in these known solutions, to obtain good electrical contact between the tool and the user, regardless of the user's grip on the tool, it is advantageous for the electrical contact surface to extend over the entire handle. This implies strong constraints both on the visual appearance and on the mechanical design of the body of the portable power tool. Brief summary of the invention

[0020] An object of the present invention is to provide a power tool free from the limitations of known power tools.

[0021] Another object of the present invention is to propose a portable electric tool which makes it possible to obtain good electrical contact between the electrical contact surface and the user, whatever the grip of the portable electric tool by the user, with fewer constraints of known solutions.

[0022] Another object of the present invention is to propose an alternative power tool to known power tools.

[0023] According to the invention, these aims are achieved in particular by means of a portable electric tool according to the invention and a method of manufacturing the portable electric tool according to the invention.

[0024] In particular, the portable electric tool according to the invention comprises: - an at least partially electrically insulating body, comprising: - an actuator, - a transmission connecting the actuator to a machining member, so as to allow movement of the machining member relative to a support member, - the machining member and / or the support member being made at least partly of electrically conductive material - at least one electrical contact surface, arranged to at least partially surround the body and to be grasped by the user, said power tool being arranged to comprise a safety system for a user, said safety system being arranged to measure an impedance between the electrical contact surface and the machining member and / or the support member, and to reduce or cancel the speed of the actuator on the basis of this impedance measurement in order to protect the user, characterized in that the electrical contact surface comprises at least two electrical contact areas which are distinct and separate, and in that the power tool comprises a connecting element made of electrically conductive material within the body of the power tool and arranged to be in electrical contact with each electrical contact area, in order to electrically connect the electrical contact areas together.

[0025] The portable electric tool according to the invention comprises: - an at least partially electrically insulating body, comprising: - an actuator, - a transmission connecting the actuator to a machining member, so as to allow movement of the machining member relative to a support member, - the machining member and / or the support member being made at least partly of electrically conductive material, - at least one electrical contact surface, arranged to at least partially surround the body and to be grasped by the user.

[0026] According to the invention, the portable electric tool is arranged to comprise a safety system for a user, this safety system being arranged to measure an impedance between the electrical contact surface and the machining member and / or the member support, and to reduce or cancel the actuator speed based on this impedance measurement in order to protect the user.

[0027] According to the invention, the electrical contact surface comprises at least two electrical contact areas which are distinct and separate, and the portable power tool comprises a connecting element made of electrically conductive material inside the body of the tool and arranged to be in electrical contact with each electrical contact area, in order to electrically connect the electrical contact areas together.

[0028] In a preferred embodiment, the connecting element is a plate. In another embodiment, it is a wire. In general, the insertion of the plate into the tool is more industrializable.

[0029] Thanks to the presence of at least two electrical contact zones which are distinct and separate and the connecting element made of electrically conductive material inside the body of the tool, it is possible to obtain good electrical contact between the tool and the user regardless of the grip of the tool by the user, because the electrical contact surface extends over the entire handle, with fewer constraints than known solutions. Indeed, the portable power tool according to the invention has a large electrical contact surface while guaranteeing great freedom of its visual appearance. The division of the electrical contact surface into several electrical contact zones connected to each other creates ribs between these zones, which reinforces the mechanical rigidity of the shell.

[0030] In one embodiment, at least one electrical contact area is flexible, namely it has a hardness belonging to the range [60-95] Shore A. This allows a firm and comfortable grip of the power tool.

[0031] In one embodiment, at least one electrical contact zone is made of elastomer.

[0032] In one embodiment, the body of the power tool is made of hard thermoplastic, namely having a hardness belonging to the range [65-90] Shore D.

[0033] In one embodiment, the power tool comprises at least ten electrical contact zones, for example twenty electrical contact zones.

[0034] In one embodiment, all of the electrical contact areas extend over the entire handle of the power tool.

[0035] In one embodiment, the connecting element made of conductive material is in, near or against an internal lateral surface of the power tool. Thus the internal volume of the tool is available for the mechanism of the tool and therefore allows the production of a compact and ergonomic tool.

[0036] In one embodiment, the connecting element made of electrically conductive material is electrically insulated, for example because it is sufficiently distant, from other components. made of electrically conductive material in the body of the power tool, such as the housing of the motor and / or gear motor of the power tool.

[0037] In one embodiment, the connecting element made of conductive material comprises means, for example holes, in order to guarantee its positioning and / or its fixing in the body of the tool.

[0038] In one embodiment, the connecting element made of conductive material comprises a tab, in particular at one of its ends.

[0039] In one embodiment, the portable power tool comprises an electrically conductive element, such as a wire, electrically connecting the plate made of conductive material, for example its tab, to an impedance measuring circuit, the machining member and / or the support member also being connected to this circuit.

[0040] The present invention also relates to a method of manufacturing the portable electric tool according to the invention, comprising the steps of: - insertion into the body of the power tool of the connecting element made of electrically conductive material, - production of at least two electrical contact zones, - electrical connection between the connecting element made of electrically conductive material and the electrical contact zones.

[0041] In one embodiment, the body of the power tool is made by plastic injection.

[0042] In one embodiment, the electrical contact zones are produced by overmolding a conductive coating, in particular a flexible conductive coating, onto the body.

[0043] In one embodiment, the insertion into the body of the portable electric tool of the connecting element made of electrically conductive material is carried out: - after overmolding the conductive coating, - before overmolding the conductive coating, or - during the production of the body of the portable electric tool. Brief description of the figures

[0044] Examples of implementation of the invention are indicated in the description illustrated by the appended figures in which:

[0045] [Fig-1] [Fig.l] illustrates a perspective view of a power tool according to a embodiment of the invention.

[0046] [Fig.2] [Fig.2] illustrates another perspective view of a portion of a tool portable electric tool according to one embodiment of the invention.

[0047] [Fig.3] [Fig.3] illustrates a front view of a power tool according to a method of realization of the invention.

[0048] [Fig.4] [Fig.4] illustrates the section along plane AA of the power tool of the [Fig.3].

[0049] Example(s) of embodiment(s) of the invention

[0050] In the figures illustrating the following description provided by way of example, reference will be made, for simplicity, to a portable electric pruning shear. The invention, however, is not limited to such an instrument. The invention is also not limited to agriculture, but also includes, for example, shears, pliers, presses, chainsaws, a portable circular saw, a portable jigsaw, a planer, a crimper, a router, etc. for agricultural, viticultural, arboricultural, industrial, craft, textile, food, medical, etc. applications.

[0051] [Fig.l] illustrates a perspective view of a portable electric tool 10 according to one embodiment of the invention. This tool is arranged to be carried by a user, for example by a member of the user such as a hand. In a variant, this same hand makes it possible to control the tool 10 via a trigger 3. In the example of [Fig.l], the portable electric tool 10 comprises a body 6, a guard 9 and a cutting head 1 comprising a machining member 4 and a support member 2. The machining member 4 and / or the support member 2 are at least partly made of electrically conductive material.

[0052] In general, the body 6 comprises two half-shells assembled together. A non-limiting example of a half-shell is illustrated in [Fig.2].

[0053] The machining member 4 makes it possible to machine an object and comes into direct contact with this object. It is movable during the machining of the object and actuated by an actuator (not shown) of the portable power tool 10, for example an electric motor.

[0054] As explained, in the context of the present invention, the word "machine" indicates any operation carried out on the object which allows it to be transformed, for example to cut, press, slice, plane etc.

[0055] The support member 2 supports the object during its machining and in general it is stationary during the machining of the object. In general, the support member is not actuated by the actuator of the power tool 10. Its presence is necessary to carry out this machining. In certain cases, the support member 2 is also mobile and / or actuated by the actuator of the power tool 10. The support member 2 also comes into direct contact with this object during its machining.

[0056] In the case where the portable power tool 10 is a pruning shear, as in the example of [Fig.l], its movable blade is the machining member 4, because it allows an object such as a branch to be cut, and the counter-blade is the support member 2, because it supports the branch during its cutting.

[0057] The power tool 10 of [Fig.l] comprises in its body a power source 8. The power source of such a power tool may be for example a battery or a battery pack. In another embodiment (not shown), the power source is a separate part of the power tool 10. In particular, the user can carry the tool with one hand and simultaneously carry the power source 8 on him, for example using a backpack, a harness or a belt.

[0058] In one embodiment, at least a portion of the body 6 of the portable electric tool 10, and preferably the entire body 6, is produced by plastic injection, with an electrically insulating material, for example a hard thermoplastic.

[0059] In the body 6 of the power tool 10 is then inserted a connecting element made of electrically conductive material 7, for example and in a non-limiting manner made of copper. This connecting element 7 is for example and in a non-limiting manner a plate, as illustrated in [Fig.l]. The plate 7 is illustrated in dotted lines in [Fig.l] to indicate that it is in the body 6 of the power tool 10.

[0060] In one embodiment, the connecting element 7 has an elongated shape. In one embodiment, the thickness of the connecting element 7 is at least one order of magnitude smaller compared to its width and / or its length. In one embodiment, the connecting element 7 has a polygonal shape, for example substantially rectangular.

[0061] In one embodiment, the connecting element 7 is partially enclosed in a half-shell of the body 6 of the tool, as for example illustrated in [Fig.4]. This is the case if for example the connecting element 7 is overmolded during the injection of the half-shell.

[0062] In one embodiment, the connecting element 7 is near or against an internal lateral surface of the power tool 10, as best seen in [Fig. 2]. In other words, its distance from the internal lateral surface of the power tool 10 concerned is less than or equal to 2 cm. This is the case if, for example, the connecting element 7 is inserted after the injection of the body 6, but before or after the overmolding of the electrical contact zones 50.

[0063] In the embodiment of figures 1 and 2, the connecting element 7 comprises at one of its ends a tab 70, substantially perpendicular to the main body of the connecting element 7. In one embodiment, the portable electric tool 10 comprises an electrically conductive element such as a wire (not shown) electrically connecting the connecting element 7, in particular the tab 70, to an impedance measurement circuit not shown, the machining member and / or the support member also being connected to this circuit.

[0064] In one embodiment, the connecting element 7 comprises means, for example holes 71, in order to guarantee its positioning and / or its fixing in the body of the portable electric tool 10, for example during the injection of the body 6 and / or to receive fixing means such as screws for example.

[0065] According to the invention, at least two electrical contact areas 50 are produced in the power tool 10, and the connecting element made of electrically conductive material 7 and the electrical contact areas 50 are electrically connected. In other words, the connecting element 7 makes it possible to connect the electrical contact areas 50. In [Fig. 4], the connecting element 7 is directly in electrical contact with the electrical contact areas 50. In other embodiments, the connecting element 7 is indirectly in electrical contact with the electrical contact areas 50, for example via (at least) one electrically conductive element such as a wire.

[0066] In one embodiment, the production of the at least two electrical contact zones 50 is carried out by overmolding on the body 6 a conductive coating, in particular a flexible conductive coating, for example a flexible conductive elastomer.

[0067] The body 6 of the portable electric tool 10, and in particular its handle 5, namely its part intended to be grasped by the user, therefore comprises at least two distinct and physically separated electrical contact zones 50, for example by a portion 60 of the body 6 which is electrically insulating.

[0068] In one embodiment, each electrical contact area 50 protrudes, for example by a few millimeters, from the electrically insulating portion 60. In other words, each electrical contact area 50 protrudes relative to the body of the tool. This makes it possible to promote electrical contact with the user.

[0069] In one embodiment, at least one electrical contact area 50, and preferably all of the electrical contact areas 50, is (are) flexible. This allows for a firm and comfortable hold of the power tool 10.

[0070] In one embodiment, at least one electrical contact zone 50, and preferably all the electrical contact zones 50, is (are) made of elastomer.

[0071] In one embodiment, the portable power tool 10 comprises at least ten electrical contact zones 50.

[0072] In one embodiment, the portable power tool and as visible in Figures 1 and 3, the electrical contact zones 50 do not necessarily have the same dimensions or the same shape.

[0073] In one embodiment, all of the electrical contact zones 50 extend over the entire handle 5 of the power tool.

[0074] In one embodiment, at least one electrical contact zone 50, and preferably all the electrical contact zones 50, is (are) arranged to at least partially surround the body 6 and to be grasped by a first member of the user, for example by a hand, in order to carry and / or operate the portable power tool 10 (for example via the trigger 3).

[0075] Although in Figures 1 and 3 each electrical contact area 50 does not completely surround the body 6, this feature is not necessary and the power tool 10 could comprise at least one electrical contact area 50 which completely surrounds the body 6 of the power tool 10.

[0076] In one embodiment, the insertion into the body 6 of the portable electric tool 10 of the connecting element 7 made of electrically conductive material is carried out: - after the overmolding of the conductive coating, - before the overmolding of the conductive coating, or - during the production of the body 6 of the portable electric tool 10.

[0077] In the example of [Fig.4], a connecting element 7 made of electrically conductive material is overmolded in each half-shell of the body of the portable electric tool 10. Reference numbers used in the figures

[0078] [Tableauxl] 1 Cutting head 2 Counter blade 3 Trigger 4 Movable blade 5 Handle 6 Body 7 Connecting element 8 Power source 9 Guard 10 Power tool 50 Electrical contact area 60 Electrically insulating portion 70 Tab 71 Holes

Claims

Claims

1. A portable power tool (10) comprising: - an at least partially electrically insulating body (6), comprising: - an actuator, - a transmission connecting the actuator to a machining member (4), so as to allow movement of the machining member (4) relative to a support member (2), - the machining member (4) and / or the support member (2) being made at least partly of electrically conductive material - at least one electrical contact surface, arranged to at least partially surround the body (6) and to be grasped by the user, said portable power tool (10) being arranged to comprise a safety system for a user, said safety system being arranged to measure an impedance between the electrical contact surface and the machining member (4) and / or the support member (2), and to reduce or cancel the speed of the actuator on the basis of this impedance measurement in order to protect the user,characterized in that the electrical contact surface comprises at least two electrical contact areas (50) which are distinct and separate, and in that the power tool (10) comprises a connecting element (7) made of electrically conductive material inside the body (6) of the power tool (10) and arranged to be in electrical contact with each electrical contact area (50), in order to electrically connect the electrical contact areas (50) together.,

2. The power tool (10) of claim 1, wherein at least one electrical contact area (50) is flexible, namely its hardness is in the range [60-95] Shore A.

3. Power tool (10) according to one of claims 1 or 2, in which at least one electrical contact zone (50) is made of elastomer.

4. Power tool (10) according to one of claims 1 to 3, wherein the body of the power tool is made of hard thermoplastic, namely its hardness belongs to the range [65-90] Shore D.

5. A power tool (10) according to one of claims 1 to 4, wherein the connecting element (7) is in, near or against an inner side surface of the power tool (10).

6. Power tool (10) according to one of claims 1 to 5, wherein the connecting element (7) comprises means, in order to guarantee its positioning and / or its fixing in the body of the tool.

7. Power tool (10) according to one of claims 1 to 6, comprising an electrically conductive element electrically connecting the connecting element (7) to an impedance measuring circuit, the machining member (4) and / or the support member (2) also being connected to this circuit.

8. Power tool (10) according to one of claims 1 to 7, wherein the connecting element (7) is a plate.

9. Method for manufacturing the portable electric tool (10) according to one of claims 1 to 8, comprising the steps of: - inserting into the body (6) of the portable electric tool (10) the connecting element (7) made of electrically conductive material, - producing the at least two electrical contact zones (50), - electrical connection between the connecting element (7) made of electrically conductive material and the electrical contact zones (50).

10. Method according to claim 9, comprising the step of producing the body (6) of the portable power tool (10) by plastic injection.

11. Method according to one of claims 9 or 10, the production of the at least two electrical contact zones (50) being carried out by overmolding a conductive coating on the body (6).

12. Method according to one of claims 9 to 11, the insertion into the body (6) of the portable electric tool (10) of the connecting element (7) made of electrically conductive material being carried out: - after overmolding of the conductive coating - before overmolding of the conductive coating, or - during the production of the body (6) of the portable electric tool (10).

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