WO2008032137A1 - Driving system comprising a screwing tool and a screw - Google Patents

Abstract

The present invention relates to a screw (1) including a threaded shank (2) and also a driving head (3) of substantially circular or polygonal cross section and having an upper surface (4) at its end opposed to the threaded shank, said head (3) comprising a hollow central portion (5) bounded at its end opposed to the threaded shank (2) by said upper surface (4) and extending axially towards the threaded shank (2) from said upper surface (4), this hollow central portion (5) forming at least two driving branches (6.1, 6.2, 6.3) situated inside the driving head (3). Said hollow central portion (5) is bounded laterally by a curved or polygonal lateral surface (7) of a specific shape. Likewise, the invention relates to a screwing tool (21) intended to be used in cooperation with such a screw (1), the tool (21) comprising a body (22) preferably including a retaining portion (25) and being terminated by a driving portion (23) intended to cooperate with the driving head (3) of the screw (1). Said driving portion (23) is bounded laterally by a curved or polygonal lateral surface (27) of a corresponding shape so as to form at least two driving flanges (26.1, 26.2, 26.3) designed to engage in the hollow central portion (5) of the driving head (3) of the screw (1).

Description

 Driving system comprising a screwdriver and a screw

The present invention relates to a screwing tool comprising a body terminating in a driving portion, said driving portion having at its end facing the body an upper surface and extending axially from that upper surface in the direction opposite to the body, this part forming at least two drive wings, and a screw intended to be used in cooperation with said screwing tool, the screw comprising a threaded rod and a section drive head; substantially circular or polygonal for cooperating with the driving portion of the screwing tool and having at its end opposite to the threaded rod an upper surface, said head comprising a hollow central portion delimited at its end opposite to the threaded rod by said upper surface and extending axially towards the threaded rod from said upper surface, this hollow central portion forming at least two drive legs located inside the drive head.

In commerce, there are many systems in this category for use in the sector of hardware, bolts, etc. These systems include a particular type of screw cavity and a corresponding tool used to screw this type of screw. It is normally not possible to use a specific tool for another type of screw. In addition, current systems have the particular disadvantage of requiring several tools, for example several screwdrivers, depending on the size of the screws used, even for a single footprint. This leads to a waste of time and a complication of the work that craftsmen and do-it-yourselfers using these systems face daily. In addition, very large screws, up to more than 1m or even 2m in length, are becoming more and more common in the market and building sites, especially in the frame, without there being a tool adequate to work comfortably with this kind of screws. Similarly, some small screws are difficult to hold in the tools currently available for this screw size, this also causing unnecessary waste of time and a difficult handling for the user and therefore a disadvantage. It is also not always easy with current systems to fit the tool into the screw head if the tool is not oriented correctly. Current systems do not all guarantee at the same time optimal resistance to deformation of the screw, improved preservation of the tool and increased coupling to achieve good adhesion between the screw, the material in which the screw is inserted, and the tool.

The object of the present invention is to overcome in particular the disadvantage of the current systems requiring several tools for the use of different sizes of screws and the disadvantage of not having simple and adequate means to hold the screw on the tool as well as realize the benefits listed above.

To this end, the present invention relates to a screw and screw tool system comprising the features set forth in claims 1 and 14.

In particular, a screwing tool according to the present invention is characterized by the features listed in claim 1, in particular by the fact that its driving portion is delimited laterally by a curved or polygonal lateral surface of a specific shape as specified in claim 1. This form ensures, on the one hand, a lateral surface narrowing substantially conically about the longitudinal axis of the tool thereby allowing engagement of the drive portion of the tool in a hollow central part of a corresponding shape of the screw head, one and the same tool can therefore be used for screws of any size, and, secondly, a substantially equal distribution of the masses between the arms of the tool and the drive legs in the screw head, which leads to an optimal resistance to deformation of the screw and a we improved the tool. Of even, the conical surface allows a guide to insert the drive portion of the tool in the screw head even if the tool is not oriented perfectly relative to said screw head, this axially and at the level relative inclination. At the same time, this specific form of the driving part of the tool as well as of the lateral surface on the screw head makes it possible, because of a 90 ° angle of attack of the force transmitted by the tool to the screw, an increased coupling so that one arrives at a better adhesion between the screw and the tool.

In addition, the screwing tool according to the present invention may further comprise a holding portion as specified in claim 2, the holding portion forming substantially an extension of the tapered drive portion and serving to hold in particular very large size having a specific portion for receiving this part of the tool. Simultaneously, the holding portion mechanically reinforces the drive portion of the tool, while allowing a universality of use of the tool for several sizes of screws because of its conical shape.

The tool may also comprise locking means located on the lateral surface of its driving portion, these locking means being preferably formed by a series of raised points, each of these series being arranged along a generator rectilinear located either on the drive wings of the drive part or in the vacuum located between said drive wings, as specified in claims 3 to 5. This feature allows for a kind of self-locking respectively of holding means for the screws of rather small or medium size which are wedged on the tool by means of points in allowance. The tool thus comprises holding means for screws of different sizes, small and large.

Correspondingly, a screw according to the invention comprises the features listed in claim 14, that is to say that it is characterized by the fact that said hollow central portion is delimited laterally by a curved or polygonal lateral surface of 'a specific form corresponding to the form mentioned above, this being necessary because the drive head of the screw is the female part and the driving part of the tool is the male part of the drive system according to the present invention. invention.

Analogously to what has been said above with respect to the tool, a screw according to the present invention may also comprise a holding portion substantially forming an extension of the drive head upwards and having inside it a space recess adapted to receive said holding portion of the screwing tool, as defined in claim 15. This allows for a holding means on the screw adapted to cooperate with the corresponding means on the tool. The technical characteristics of the proposed system thus make it possible to solve the aforementioned drawbacks.

Other advantages emerge from the features expressed in the dependent claims and from the description which sets forth the invention in more detail with the aid of drawings.

The accompanying drawings illustrate schematically and by way of example a drive system according to the present invention.

FIG. 1 schematically illustrates the principle of such a drive system by showing a longitudinal section of a screw according to the present invention, the hollow central part being shown in side view, a tool engaging in the screw head being marked in dotted lines.

Figure 2a is a schematic top view of a screw head according to a first embodiment, the section line of Figure 1 being marked by the line l-1; Figure 2b shows a top view of a screw head according to a second embodiment.

Figure 3 shows the side of the drive part of a tool according to the present invention.

Figure 4a is a schematic bottom view of the driving portion of a tool according to a first embodiment; FIG. 4b represents a view from the bottom of the driving portion of a tool according to a second embodiment.

Figures 5a and 5b illustrate in perspective a screwing tool and a corresponding screw similar to the embodiment illustrated in Figures 1 and 2a, but further comprising holding means.

The invention will now be described in detail with reference to the accompanying drawings.

The drive system according to the present invention, and shown by way of example in Figure 1 by a longitudinal section, comprises a screw 1 with a hollow central portion 5 in a screw head 3 and a tool 21 adapted to s' engage in said screw head 3.

This screw 1 conventionally comprises a threaded rod 2 and a drive head 3 of a thickness chosen according to the size of the screw and of substantially circular or polygonal section and having at its end opposite to the threaded rod a upper surface 4. This drive head 3 comprises a hollow central portion 5 delimited at its end opposite to the threaded rod 2 by said upper surface 4 and extends axially in the direction of the threaded rod 2 from said upper surface 4 As shown in FIGS. 2a or 2b, the hollow central part 5 forms at least two driving branches 6.1, 6.2, 6.3 located inside the driving head 3 which allow the transfer of a torque to the screw via a screwdriver.

The hollow central portion 5 is distinguished in particular by the fact that it is delimited laterally by a curved or polygonal lateral surface 7 of a complex shape to ensure perfect coupling with a single tool for different sizes of screws. The use of such a universal tool with the corresponding screws allows a significant gain in speed for all work involving the sector of hardware and bolts. This lateral surface 7 is generated by rectilinear generatrices 7.1 extending between a path 8 closed on itself located in said upper surface 4 and a point of intersection 9 of said generators located at the maximum depth of the hollow central portion 5. along the longitudinal axis 10 of the screw 1, as shown schematically in Figures 2a and 2b.

The path 8 is composed, for each driving branch 6.1, 6.2, 6.3, of a first part 8.1 located radially further inwards, of two second parts 8.2 situated radially further out and situated laterally on the side and else of the first part 8.1 and two intermediate parts 8.3 connecting each first part 8.1 to the two second parts 8.2 neighbors.

In order to improve the transfer of the rotational moment of the tool to the screw, each intermediate part 8.3 is located in its middle part in a tangent plane 8.4 at the point of reversal 8.5 between the first part 8.1 and the second part 8.2 of the trace 8, the tangent plane 8.4 passing through the longitudinal axis 10 of the screw 1. This has the consequence that the drive legs 6.1, 6.2, 6.3 widen outwardly, thus stabilizing them. This constellation is best illustrated in FIG. 2a, which also shows that this design allows the angle of attack of the force F transmitted by the tool to the screw to be thus perpendicular to the lateral surface of each driving limb. 6.1, 6.2, 6.3 of a screw head 3. This makes it possible to obtain an increased coupling so that a better adhesion between the screw and the tool is achieved. Nevertheless, it is possible to arrange the intermediate portions 8.3 in a plane parallel to said tangential plane 8.4, the coupling being in this case slightly smaller as a function of the offset of the plane parallel to the tangent plane 8.4, because the angle d Attack is no longer exactly a right angle.

The rectilinear generatrices 7.1 generating the lateral surface of the hollow central portion 5 of the head 3 of the screw 1 go from each point along the path 8 substantially conically about the longitudinal axis 10 of the screw 1 towards the intersection point 9 mentioned above. This characteristic is the fact that the driving part of the tool must be able to fit over the entire lateral surface of the hollow central portion without encountering any obstacle. Simultaneously, even if the angle between a rectilinear generatrix 7.1 and the longitudinal axis 10 of the screw 1 varies along the path 8, because this angle is always identical to a given point along the path 8 for the different sizes of screw, that is to say the fact that the conicity at this point is always the same, one and the same tool for all the screws, even of different sizes is sufficient, since this tool has the same side surface. In a simplified manner, this characteristic can be expressed by the fact that the always identical conical shape of the hollow central portion of the screws of all the magnitudes according to the present invention allows the use of a single universal tool having this same shape.

In addition, the angle β between two tangent planes 8.4 respectively between two parallel planes as evoked above adjacent a driving branch 6.1, 6.2, 6.3 of a drive head 3 is identical for each branch of drive 6.1, 6.2, 6.3. These branches are also at an equivalent angular distance α, so that the tool can be inserted without geometric preference between the drive legs.

To return to the first - 8.1 and second parts 8.2 of the above-mentioned layout, it should be noted that they preferably have a shape and a length so that the annular or polygonal volume 11 included radially between these first - 8.1 and second parts 8.2 is distributed equally between each drive leg 6.1, 6.2, 6.3 and each vacuum 11.1, 11.2, 11.3 located between said drive legs 6.1, 6.2, 6.3 in said volume 11, this vacuum 11.1, 11.2, 11.3 forming part of the hollow central part 5. In other words, the mass of the driving legs 6.1, 6.2, 6.3 of a screw 1 is equivalent to the mass of the driving wings of the driving part. of the tool which are placed in the vacuum 11.1, 11.2, 11.3 between the drive legs 6.1, 6.2, 6.3 when screwing a screw, assuming that the branches and the wings are made using the same material. This feature makes it possible to obtain a better resistance to the deformation of the screw, which is of importance especially for the screws of very small size, and an improved preservation of the tool, thus preventing premature wear of the tool . Preferably, the first - 8.1 and second parts 8.2 have a rounded shape as shown schematically in Figure 2a. In particular, it is preferable that the first parts 8.1 are concave and the second parts 8.2 are convex.

In this case, the intermediate parts 8.3 comprise a convex part and a concave part, so that the point of recoil between these two parts forms the cusp point 8.5 between the first - 8.1 and the second part 8.2.

Alternatively, it is possible to choose a linear form of the first - 8.1 and second parts 8.2 as well as intermediate parts 8.3. It should be noted in this context that the exact shape of the screw as well as that of the corresponding driving part of the tool can vary considerably while maintaining the characteristics stated above and appearing in the independent claims 1 and 9. By For example, it is clear that a linear shape can be obtained also by more than three linear parts per limb respectively drive arm as shown schematically in Figure 2b and a rounded shape for these parts could have a different structure than that illustrated by way of example in Figure 2a.

With regard to the number of the driving limbs 6.1, 6.2, 6.3, it is preferable that the screw 1 comprises three or four. In addition, to enhance the stability of these branches 6.1, 6.2, 6.3 of the screw

1, the first parts 8.1 are remote from the longitudinal axis 10 of the screw 1 and are normally located at a radial distance from the longitudinal axis 10 corresponding substantially to half the radial distance of the second parts 8.2. Compared to the important advantage of such a screw 1 to require only one and the same tool for the various sizes of screws, it is also noted that the intersection point 9 marked for example in Figure 1 can actually constitute the point of the maximum depth of the hollow central portion 5 along the longitudinal axis 10 of the screw 1. This is however not mandatory and the hollow central portion 5 can also be completed before this point of intersection 9 along the longitudinal axis 10 of the screw 1 forming a lower surface 12, preferably parallel to said upper surface 4 located at the opposite end to the threaded rod, as illustrated by a dotted line in Figure 1. Furthermore, a screw according to the present invention may further comprise a holding portion 13 extending axially from the upper surface 4 of the driving head 3 of the screw 1 in the opposite direction to the threaded rod. 2, as shown schematically in FIG. 5b. The holding portion 13 substantially forms an extension of the drive head 3 of the same section and the same diameter as the latter at its maximum diameter. Inside, this portion 13 has a hollow space 14 of the same section and the same diameter as the hollow central portion 5 in the drive head 3 at its maximum diameter, this hollow space 14 being thus adapted to receive a portion The upper surface 4 becomes in this case a dummy plane separating the hollow central portion 5 of conical shape and the hollow space 14 of linear shape. The holding portion 13 is formed in particular on the head of the very large screws, of about 1m or even 2m in length or more, and defines in this case the maximum size of the tool that can still inserted into its head. training. On the other hand, the screws of medium or small size do not normally comprise such a holding portion, the tool having another system for holding them, as will be explained in more detail below. The holding portion 13, normally present only on the very large screws, does not generate then actually not the universality of use of the tool 21 for several sizes of screws.

To describe in turn the screwing tool 21 corresponding to the present invention, it is clear that it is intended to be used in cooperation with a screw 1 as described above. This tool 21 comprises a body 22 for manually gripping the tool or attaching it to any machine. The body 22 terminates in a driving portion 23 intended to cooperate with the driving head 3 of the screw 1. The driving portion 23 has at its end facing the body 22 an upper surface 24 and extends axially from this upper surface 4 in the direction opposite to the body 22. This part 23 forms at least two drive wings 26.1, 26.2, 26.3 which are intended to engage between the drive legs 6.1, 6.2, 6.3 of the screw 1.

As mentioned above and required by the cooperation between the tool 21 and the screw 1, said driving portion 23 is delimited laterally by a corresponding curved or polygonal lateral surface 27 generated by rectilinear generatrices 27.1 extending between a path 28 closed on itself located in said upper surface 24 and a point of intersection 29 of said generators located at the point of maximum extension of the driving portion 23 along the longitudinal axis 30 of the tool 21, as this is shown schematically in Figures 3, 4a and 4b.

The pattern 28 is composed, for each drive wing 26.1, 26.2, 26.3, a second portion 28.2 located radially further out, two first portions 28.1 located radially further in and laterally located side and other part of the second part 28.2 and two intermediate parts 28.3 connecting each second part 28.2 to the two neighboring first parts 28.1.

Again, each intermediate portion 28.3 is located in its middle portion in a tangential plane 28.4 at the cusp 28.5 between the first - 28.1 and the second portion 28.2, this tangential plane 28.4 passing through the axis Longitudinal 30 of the tool 21. As explained above, the angle of attack of the force F between the tool and the screw is due to this design perpendicular to the lateral surface of each drive wing 26.1, 26.2 , 26.3 of the drive portion 23 of the tool 21. Similarly, depending on the arrangement of the screw with respect to this point, the middle portion of the intermediate portions 28.3 may also be located in a plane parallel to the said tangential plane 28.4, the angle of attack then being slightly different from a right angle.

Also, the straight generatrices 27.1 go from each point along the path 28 substantially conically about the longitudinal axis 30 of the tool 21 to the point of intersection 29, so as to allow the insertion of the the driving part 23 of the tool 21 in the hollow part 5 of the driving head 3 of a screw 1, in the same way for all the screw sizes.

The angle α between two adjacent tangent planes 28.4 respectively between two parallel planes as mentioned above of a drive wing 26.1, 26.2,

26.3 is identical for each drive wing 26.1, 26.2, 26.3, these wings being located at an equivalent angular distance β.

Said first - 28.1 and second portions 28.2 of the pattern 28 of the driving portion 23 have a shape and a length so that the annular or polygonal volume 31 included radially between the first - 28.1 and second parts 28.2 is divided in such a way that equal between each drive wing 26.1, 26.2, 26.3 and each empty 31.1, 31.2, 31.3 located between said drive wings 26.1, 26.2, 26.3 in said volume 31. This characteristic allows, as already mentioned, an equal distribution of the masses. between the drive legs 6.1, 6.2, 6.3 of a screw 1 and the drive wings 26.1,

26.2, 26.3 of the tool 21, this being favorable to the resistance to deformation of the screw as well as the tool.

As in the case of screw 1, the first - 8.1 and second parts

8.2 as well as the intermediate parts 8.3 of the layout 28 of the training part 23 of the tool 21 may have a shape either rounded or linear.

Obviously, this shape must be chosen in consultation with the shape of the corresponding portions of the path 8 of the hollow central portion 5 of the drive head 3 of the screw 1. Indeed, since it is the specific complex shape of said lateral surfaces 7, 27 which is important for a screw 1 and a tool 21 according to the present invention, the explanations above are generally applicable to both cases.

The tool 21 preferably comprises three or four drive wings 26.1, 26.2, 26.3 to engage between the drive legs 6.1, 6.2, 6.3 of a screw 1.

In a similar way to the case of the screw 1, whose intersection point 9 marked for example in Figure 1 can actually be the point of the maximum depth of the hollow central portion 5 along the longitudinal axis 10 of the screw 1, the driving portion 23 of the tool 21 may be pointed, the point of intersection 29 of said generators 7.1 located at the point of maximum extension of the driving portion 23 along the longitudinal axis 30 of the tool 21 then actually constituting a point on the drive portion 23 of the tool 21. However, this portion 23 can also be terminated before this point of intersection 29 along the longitudinal axis 30 of the tool 21 forming a lower surface 32, preferably parallel to said upper surface 24 located at the end facing the body 22. The two cases are illustrated in Figure 3, the choice of the size of the lower surface 32 in effect determining the size minimum of the screw which can still be used in cooperation with the tool 21.

The screwing tool according to the present invention may, preferably, further comprise a holding portion 25 as shown in Fig. 5a in a perspective view. In this case, this holding portion 25 extends axially from the upper surface 24 of the driving portion 23 of the tool 21 in the direction towards the body 22 and substantially forms a kind of extension of the part of the conical drive 23 of the same section and the same diameter as the latter at the level of its maximum diameter. Obviously, the driving portion 23, the holding portion 25 and the body 22 are normally formed in one piece, the upper surface 24 of the driving portion 23 becoming a fictitious plane delimiting the conical portion of the section. the upper surface physically located at the end of the linear extension also participating in driving the screw. The holding portion 25 is used in particular to attach very large screws up to 1m or even 2m, as they are currently increasingly used, and also provides a reinforcement of the drive wings of the tool 21. Furthermore, the holding portion 25 does not in any way to the universality of use of the tool 21 for several sizes of screws.

In addition, the screwing tool may also comprise locking means 33 which are situated on the lateral surface 27 of the driving portion 23 of the tool 21. These locking means 33 are advantageously formed by a series of points in elevation 33.1. Each series of elevation points 33.1 is preferably arranged along one of the straight generatrices 27.1 mentioned above and located on the drive wings 26.1, 26.2, 26.3 of said drive portion 23, preferably at the middle of these wings, as shown schematically in Figure 4a. Alternatively, these points can be placed in the vacuum 31.1, 31.2, 31.3 located between said drive wings 26.1, 26.2, 26.3, preferably in the middle of this vacuum as shown in Figure 5a. They may, in general, be distributed evenly on the flanks of the drive wings and do not necessarily have to be in alignment with one another. These raised points 33.1 form a means for jamming a screw 1 in the head 3 of which the drive portion 23 of the tool 21 is inserted and then make it possible to hold a screw 1 on the tool 21, in particular screws short. The locking means 33 and the raised points 33.1 are preferably placed on the tool because the screws are usually made of a softer material and then allow to be stuck on the tool as suggested. above. It is nevertheless possible to equip the screws of these raised points in an analog manner on the lateral surface 7 of their hollow central portion 5. The tool according to the present invention thus comprises with the holding portion 25 and the locking means 33. means for holding screws of various sizes on the tool.

The assembly formed by a screw 1 and a screwing tool 21 constitutes a drive system according to the present invention which has the features and advantages mentioned above. In particular, we obtain by these measures a universal tool being adapted to screw all the same screws of different size, which results in a significant speed gain. Moreover, this system makes it possible to have a complete range for each use, like the frame, the do-it-yourself, etc., with only two components, the screws and the corresponding tool. The system still proposes means for holding the screws on the tool, this in a manner suitable for the screws is small or large. In addition, both the tool and the screw have features that help to reduce the wear of the screws and the tool and at the same time ensure increased coupling between the screw, the material in which the screw is inserted, and the tool, as explained above, and perform an easy interlocking of the tool in the screw.

Claims

claims A screwing tool (21) comprising a body (22) terminating in a driving portion (23), said driving portion (23) having at its body-facing end (22) an upper surface (24); ) and extending axially from this upper surface (4) in the opposite direction to the body (22), this portion (23) forming at least two drive wings (26.1, 26.2, 26.3), characterized in that - said driving portion (23) is delimited laterally by a curved or polygonal lateral surface (27) generated by rectilinear generatrices (27.1) extending between a self-contained path (28) in said upper surface (24) and a point of intersection (29) of said generators at the point of maximum extension of the drive portion ( 23) along the longitudinal axis (30) of the tool (21), - said pattern (28) being composed, for each drive wing (26.1, 26.2, 26.3), of a second portion (28.2) located radially further out, of two first portions (28.1) located radially further to the interior and located laterally on either side of the second portion (28.2) and two intermediate portions (28.3) connecting each second portion (28.2) to the two neighboring first parts (28.1), - each intermediate part (28.3) being situated in its median part in a tangent plane (28.4) at the cusp (28.5) between the first - (28.1) and the second part (28.2), this tangent plane (28.4) passing through the longitudinal axis (30) of the tool (21), or in a plane parallel to said tangent plane (8.4) - said rectilinear generatrices (27.1) going from each point along the path (28) substantially conically about the longitudinal axis (30) of the tool (21) to the point of intersection (29), the angle (α) between two tangent planes (28.4) adjacent to a training wing (26.1, 26.2, 26.3) being identical for each drive wing (26.1, 26.2, 26.3), these wings being located at an equivalent angular distance (β). 2. Screwing tool according to the preceding claim, characterized in that it further comprises a holding portion (25) extending axially from the upper surface (24) of the driving portion (23) of the tool (21) in the direction towards the body (22), the holding portion (25) substantially forming an extension of the conical driving portion (23) of the same section and the same diameter as the latter at its level. maximum diameter. 3. Screwing tool according to one of the preceding claims, characterized in that it comprises locking means (33) located on the lateral surface (27) of the drive part (23) of the tool ( 21). 4. Screwing tool according to the preceding claim, characterized in that the locking means (33) are formed by a series of points in elevation (33.1). 5. Screwing tool according to the preceding claim, characterized in that each series of raised points (33.1) is arranged along one of said rectilinear generatrices (27.1) located either on the drive wings (26.1, 26.2, 26.3) of said drive part (23), preferably in the middle of these wings, or in the vacuum (31.1, 31.2, 31.3) situated between said drive wings (26.1, 26.2, 26.3), preferably in the middle from this void. 6. Screwing tool according to one of the preceding claims, characterized in that the annular or polygonal volume (31) included radially between the first - (28.1) and second parts (28.2) being distributed evenly. between each driving wing (26.1, 26.2, 26.3) and each void (31.1, 31.2, 31.3) located between said drive wings (26.1, 26.2, 26.3) in said volume (31). 7. Screwing tool according to one of the preceding claims, characterized in that the first - (28.1) and second parts (28.2) are rounded. 8. Screwing tool according to the preceding claim, characterized in that the first parts (28.1) are concave and the second parts (28.2) convex. 9. Screwing tool according to the preceding claim, characterized in that the intermediate parts (28.3) comprise a convex portion and a concave portion, the point of recoil between these two parts forming the cusp (28.5) between the first - (28.1) and the second part (28.2). 10. Screwing tool according to one of claims 1 to 6, characterized in that the first - (28.1) and second parts (28.2) and the intermediate parts (28.3) are linear. 11. Screwing tool according to one of the preceding claims, characterized in that it comprises three or four drive wings (26.1, 26.2, 26.3). 12. Screwing tool according to one of the preceding claims, characterized in that the first parts (28.1) are located at a radial distance from the longitudinal axis (10) substantially corresponding to half the radial distance of the second parts. (28.2) to enhance the stability of the drive wings (6.1, 6.2, 6.3). Screwing tool according to one of the preceding claims, characterized in that the driving part (23) ends before the point of intersection (29) along the longitudinal axis (30) of the tool (21) forming a bottom surface (32) parallel to said upper surface (24) at the body-facing end (22). 14. Screw (1) intended to be used in cooperation with a screwing tool (21) according to one of the preceding claims, the screw (1) comprising a threaded rod (2) and a driving head (3). ) of substantially circular or polygonal section intended to cooperate with the driving part (23) of the screwing tool (21) and having at its opposite end to the threaded rod an upper surface (4), said head (3) comprising a hollow central portion (5) delimited at its opposite end to the threaded shank (2) by said upper surface (4) and extending axially towards the threaded shank (2) from said upper surface (4) , this hollow central portion (5) forming at least two drive legs (6.1, 6.2, 6.3) located inside the driving head (3), characterized by the fact that said hollow central portion (5) is delimited laterally by a curved or polygonal lateral surface (7) generated by rectilinear generatrices (7.1) extending between a path (8) closed on itself situated in said upper surface (4); ) and a point of intersection (9) of said generators located at the maximum depth of the hollow central portion (5) along the longitudinal axis (10) of the screw (1), said path (8) being composed, for each driving limb (6.1, 6.2, 6.3), of a first portion (8.1) located radially further inwards, of two second portions (8.2) located radially further to the outside and located laterally on either side of the first part (8.1) as well as two intermediate parts (8.3) connecting each first part (8.1) to the two neighboring second parts (8.2), - each intermediate part (8.3) being situated in its median part in a tangent plane (8.4) at the cusp (8.5) between the first - (8.1) and the second part (8.2), this tangent plane (8.4) passing through the longitudinal axis (10) of the screw (1), or in a plane parallel to said tangent plane (8.4), - said rectilinear generatrices (7.1) going from each point along the path (8) substantially conically about the longitudinal axis (10) of the screw (1) towards the point of intersection (9), the angle (β) between two adjacent tangent planes (8.4) of a driving branch (6.1, 6.2, 6.3) being identical for each driving branch (6.1, 6.2, 6.3), these branches being situated at an equivalent angular distance (α). 15. Screw according to the preceding claim, characterized in that it further comprises a holding portion (13) extending axially from the upper surface (4) of the drive head (3) of the screw ( 1) in the opposite direction to the threaded rod (2), the holding portion (13) substantially forming an extension of the drive head (3) of the same section and of the same diameter as the latter at its maximum diameter and having in its interior a hollow space (14) of the same section and the same diameter as the hollow central portion (5) in the drive head (3) at its maximum diameter, this hollow space (14) being adapted receiving said holding portion (25) of the screwing tool (21). 16. Screw according to one of claims 14 to 15, characterized in that the annular or polygonal volume (11) radially between the first - (8.1) and second parts (8.2) being distributed equally between each branch of (6.1, 6.2, 6.3) and each vacuum (11.1, 11.2, 11.3) located between said driving legs (6.1, 6.2, 6.3) in said volume (11), this void (11.1, 11.2, 11.3) forming part of the hollow central portion (5). 17. Screw according to one of claims 14 to 16, characterized in that the first - (8.1) and second parts (8.2) and the intermediate parts (8.3) are either rounded or linear. 18. Screw according to one of claims 14 to 17, characterized in that it comprises three or four drive legs (6.1, 6.2, 6.3). Screw according to one of claims 14 to 18, characterized in that the hollow central portion (5) terminates before the point of intersection (9) along the longitudinal axis (10) of the screw ( 1) by forming a lower surface (12) parallel to said upper surface (4) located at the opposite end to the threaded rod. 20. Drive system comprising a screwdriver according to one of claims 1 to 13 and a screw according to one of claims 14 to 19.