Drive element

Abstract

The present invention relates to a drive element which has an outer driver profile (3) which defines a profile axis (PA) and has, on its outer side, a plurality of concave, i.e. curved to the interior of the driver profile (3) and in particular to the profile axis (PA), drive surfaces (4) which are evenly distributed about the profile axis (PA) and between which planar or convexly curved transition surfaces (5) are provided, wherein the drive surfaces (4), in two planes which define the profile axis (PA) and are perpendicular to one another, are inclined with respect to the profile axis (PA) in such a way that the drive surfaces (4) approach the profile axis (PA) towards a front insertion end of the outer driver profile (3) and, when the outer driver profile (3) of the drive element is in engagement with an inner driver profile (8) of a further drive element designed to be complementary to the outer driver profile, a torque is transmitted from the driving drive element to the driven drive element via the interaction of the drive surfaces (4, 10) in a direction of rotation of a driving drive element about the profile axis, while in the other direction of rotation, the interaction of the drive surfaces (4, 10) causes an axial displacement of the driven drive element in order to bring the driving profiles (3, 8) out of engagement.

Description

[0001] DESCRIPTION

[0002] drive element

[0003] The present application relates to a drive element having an outer drive profile according to the preamble of claim 1, a drive element having an inner drive profile according to the preamble of claim 7, and a method for connecting two components, in particular a screw and a rotary tool, according to the preamble of claim 13.

[0004] Screws and turning tools are known in various designs from the prior art. The screws comprise a screw shank with an external thread, at the upper end of which a drive profile is provided for coupling with a turning tool, which is usually formed on the screw head. The turning tools are, for example, in the form of ring or open-end wrenches, or they include interchangeable bits that are connected via a bit holder to a drive, such as a handle or a cordless screwdriver. Alternatively, the bit holder can be connected via an adapter for interchangeable use with a screwdriver handle or an angled handle, a ratchet, a torque wrench, a cordless screwdriver, or a ratchet screwdriver.

[0005] To transmit torque from the turning tool to the screw, the screw and turning tool are offered with complementary drive profiles. One of the two components has an outer drive profile with external drive surfaces at one of its free ends, while the other component has an inner drive profile with internal drive surfaces at its other free end, complementary to the outer drive profile. The drive profiles are designed, for example, as an internal hexagon, an external hexagon, a Torx profile, a Phillips head profile, or a slotted profile. After the inner drive profile engages with the outer drive profile, the drive profiles have some play. This can lead to the drive profiles unintentionally separating from each other, and it is also not possible to align the drive profiles precisely axially.To simplify handling when tightening and loosening screws with a turning tool, turning tools equipped with a magnet, or ferromagnetic turning tools that can be magnetized with a magnet, are offered. However, this involves additional effort. Furthermore, the use of a magnetic turning tool does not allow for coaxial alignment of the drive profiles. Such coaxial alignment is necessary, however, to integrate screw connections into automated manufacturing processes.

[0006] To solve this problem, EP2 321 542 B1 proposes a drive system with a screw and a rotary tool whose drive profiles are tapered. Furthermore, the outer drive profile has concave drive surfaces in the shape of circular arc segments, curving inwards towards the profile axis, and the inner drive profile has complementary drive surfaces. The arrangement is such that, when assembled, the drive surfaces of the two components, viewed circumferentially, come into contact / engage over a surface area on both sides of the apex of the concave curvature. This design creates not only a positive-locking and rotationally fixed connection but also a frictional or clamping connection between the screw and the rotary tool, through which the components are axially connected and coaxially aligned. Furthermore, the force or...Torque transmission occurs exclusively via the surface contact that takes place on both sides of the apex of the circularly curved drive surfaces, while there is no contact in the transition areas / surfaces located between the drive surfaces. In this way, damage to the edges or peripheral areas of the drive surfaces can be completely avoided.

[0007] The well-known drive system has proven itself in practice. However, there is a desire for drive systems that prevent a screw connection from loosening once it has been made.

[0008] Accordingly, the object of the present invention is to design the previously known drive system in such a way that it enables the production of a screw connection, but prevents the loosening of such a connection.

[0009] This problem is solved in a drive element of the type mentioned above, which has an outer drive profile, by the characterizing features of claim 1, and in a drive element of the type mentioned above, which has an inner drive profile, by the characterizing features of claim 7. Furthermore, the problem is solved in a method for rotationally fixedly connecting two components, in particular a screw and a rotary tool, of the type mentioned above by the characterizing features of claim 13. The invention is based on the consideration of inclined the drive surfaces of the drive profiles relative to the respective profile axis in two mutually perpendicular planes, each enclosing the profile axis, to such an extent that torque transmission from a driving drive element to a driven drive element is possible in one direction of rotation, but prevented in the other direction of rotation.Specifically, the inclination of the drive surfaces results in the generation of forces during torque transmission that press the drive profiles of the two drive elements against each other, while in the opposite direction of rotation, forces are generated that separate the two drive profiles, i.e., push them axially apart. Furthermore, the inclination of the drive surfaces allows for the transmission of high torques even with flat profiles and prevents damage to the profile during screw insertion, as the bit is pulled into the profile along with the screw.

[0010] In the drive system known from EP 2321 542 B1, the drive surfaces of the drive profiles are aligned parallel to the respective profile axis or pivoted in a predetermined plane relative to the profile axis such that the drive surfaces are conically tapered. In contrast, in the solution according to the invention, the drive surfaces are additionally pivoted in a further plane perpendicular to the predetermined plane in order to achieve the desired inclination relative to the profile axis.

[0011] For example, the drive surfaces can each have the basic shape of a cylindrical shell section inclined in both planes relative to the profile axis, or the basic shape of a rectangle inclined in both planes relative to the profile axis. However, when viewed in cross-section, the drive surfaces of the drive element according to the invention do not have a continuous cylindrical shell section or rectangular shape. Due to the inclination of the drive surfaces, a drive surface with the basic shape of a cylindrical shell exhibits parabolic and / or elliptical sections in cross-section. Only partial sections of the drive surface retain the shape of a cylindrical shell section in cross-section after being pivoted twice in the two pivot planes. When these are connected centrally, a longitudinal axis of the respective drive surface is obtained.

[0012] In a preferred embodiment of the invention, the drive surfaces, and in particular their longitudinal directions, each form an angle with a plane perpendicular to the profile axis. This angle is between 20° and 70°, particularly between 30° and 60°, and preferably 45 ± 5°. The longitudinal directions of the drive surfaces are determined by their longitudinal axes, and the angle is measured in a plane that includes the longitudinal axis of the respective drive surface and the profile axis.

[0013] The drive surfaces of the inner drive profile are preferably designed such that the drive surfaces of a complementary outer drive profile can be brought into contact with them in a planar and frictional manner. Similarly, the drive surfaces of the outer drive profile are designed such that the drive surfaces of a complementary inner drive profile can be brought into contact with them in a planar and frictional manner. This planar and frictional connection ensures that the drive profiles are axially connected and that torque transmission can occur via frictional engagement.In a manner known per se, the transition surfaces can be inclined relative to the profile axis such that they approach the profile axis towards a front insertion end of the outer drive profile, wherein, in particular, the angle of inclination is at least 10°, in particular at least 20° and preferably at least 30° and / or at most 60°, in particular at most 50° and preferably at most 45°, wherein the angle of inclination is preferably 45 ± 5°.In a drive element with an inner drive profile, the transition surfaces are inclined relative to the profile axis in such a way that they approach the profile axis from an insertion opening of the inner drive profile to a front, inner end of the inner drive profile, wherein, in particular, the angle of inclination is at least 10°, in particular at least 20° and preferably at least 30° and / or at most 60°, in particular at most 50° and preferably at most 45°, wherein the angle of inclination is preferably 45 ± 5°.

[0014] Preferably, the drive element is designed with an outer drive profile as a turning tool, in particular as a screw bit, while the drive element with an inner drive profile is designed as a screw.

[0015] Further features and advantages of the present invention are explained with reference to the accompanying drawing. The drawing shows:

[0016] Figure 1 shows a perspective view of a drive element designed as a screwdriver bit according to the present invention with an outer drive profile having three drive surfaces; Figure 2 shows the drive element from Figure 1 in a front view.

[0017] Figure 3 shows a perspective view of a screw head with an internal drive profile, which is part of a drive element designed as a screw according to the present invention.

[0018] Figure 4 shows the screw head on Figure 3, in a rear view,

[0019] Figure 5 shows the screw head from Figure 4 in section along line AA,

[0020] Figure 6 shows a front view of a drive element designed as a screwdriver bit with an outer drive profile according to the present invention, which has four drive surfaces,

[0021] Figure 7 shows a perspective view of the drive element from Figure 6.

[0022] Figure 8 shows another perspective view of the drive element according to Figure 6,

[0023] Figure 9 shows a front view of the drive element from Figure 6.

[0024] Figure 10 shows a perspective view of a drive element designed as a screw with an inner drive profile, which has four drive surfaces, according to the present invention.

[0025] Figure 11 shows the screw head from Figure 10 in top view. Figure 12 shows a perspective longitudinal section through the screw head of Figure 11, along line AA from Figure 11.

[0026] Figure 13 shows the screw head from Figure 11 in section along line AA and

[0027] Figure 14 shows the screw head from Figure 11 in section along line BB.

[0028] Figures 1 and 2 show a drive element according to the present invention in the form of a rotary tool 1, specifically a screwdriver bit. The rotary tool 1 has a tool shank 2, at the front end of which an outer drive profile 3 is provided. The outer drive profile 3 defines a profile axis PA that runs coaxially to the longitudinal axis of the tool shank 2 and has three drive surfaces 4 that are concave, i.e., curved towards the interior of the outer drive profile 4. The drive surfaces 4 have the basic shape of a cylindrical shell segment, thus possessing the cross-section of a circular segment. However, according to the invention, the drive surfaces 4 are inclined relative to the profile axis PA in two mutually perpendicular planes, each of which encloses the profile axis PA.The drive surfaces 4 are inclined in a predetermined first plane relative to the profile axis PA to create a conical shape such that they approach the front end—the insertion end—of the outer drive profile 3. From this inclined position, the drive surfaces 4 are further tilted in a second plane perpendicular to the predetermined first plane, as shown in Figures 1 and 2. Convex transition surfaces 5 are provided between the drive surfaces 4, connecting them and lying on common circles in cross-section. The transition surfaces 5 are conical, meaning they are inclined relative to the profile axis PA such that they approach the free insertion end of the outer drive profile 3. The angle of inclination is between 10° and 60° and is approximately 20° in the illustrated embodiment.

[0029] Figures 3 to 5 show a drive element according to the present invention in the form of a screw 6. The screw 6 has a screw shank (not shown) at the rear end of which a screw head 7 is provided with an inner drive profile 8, which is open towards the rear of the screw 6 and defines an insertion opening 9. The inner drive profile 8 defines a profile axis PI, which runs coaxially to the longitudinal axis of the screw shank, and has three drive surfaces 10, which are concave, i.e., curved towards the interior of the inner drive profile 8.

[0030] The inner drive profile 8 of the screw 6 is designed to be complementary to the outer drive profile 4 of the turning tool 1, so that the drive profiles 3, 8 can be axially connected together and then the drive surfaces 4, 10 come into contact with each other and are clamped together.

[0031] Accordingly, the drive surfaces 9 of the inner drive profile 8, like the drive surfaces 4 of the outer drive profile 3, are inclined relative to the profile axis PI in two mutually perpendicular planes, each enclosing the profile axis PI, as per the invention. The drive surfaces 10 are inclined in a predetermined first plane relative to the profile axis PI to create a conicity of the drive surfaces 4 such that the drive surfaces 10 approach the front inner end of the inner drive profile 8 from the insertion opening 9. From this inclined position, the drive surfaces 10 are additionally tilted in a second plane perpendicular to the predetermined first plane, as can be seen in Figures 3 and 5.

[0032] Convex transition surfaces 11 are provided between the drive surfaces 10, connecting them and lying on common circles in cross-section. The transition surfaces 11 are conically shaped, meaning they are inclined relative to the profile axis PI such that they approach the front, inner end of the inner drive profile 8. The angle of inclination is between 10° and 60° and is approximately 20° in the illustrated embodiment.

[0033] According to the invention, the drive surfaces 4, 10 of the drive profiles 3, 8 are inclined relative to their respective profile axes PA, PI in two mutually perpendicular planes, each enclosing the profile axis, to such an extent that torque transmission from the driving rotary tool 1 to the driven screw 6 is possible in one direction of rotation, but prevented in the other direction. Specifically, the inclination of the drive surfaces 4, 10 results in forces being generated during torque transmission that press the drive profiles 3, 8 of the two drive elements against each other, while in the other direction of rotation, forces are generated that separate the two drive profiles 3, 8 from each other, i.e., push them axially apart.

[0034] Figures 6 to 9 show another drive element according to the present invention in the form of a rotary tool 1, specifically a screwdriver bit. The rotary tool 1 has the same structure as the rotary tool 1 shown in Figures 1 and 2, with the sole difference that the rotary tool has four drive surfaces 4 instead of three. The preceding descriptions apply accordingly.

[0035] Specifically, the rotary tool has a tool shank 2, at the front end of which an outer drive profile 3 is provided. The outer drive profile 3 defines a profile axis PA that runs coaxially to the longitudinal axis of the tool shank 2 and has three drive surfaces 4 that are concave, i.e., curved towards the interior of the outer drive profile 4. The drive surfaces 4 have the basic shape of a cylindrical shell segment, thus possessing the cross-section of a circular segment. However, according to the invention, the drive surfaces 4 are inclined relative to the profile axis PA in two mutually perpendicular planes, each of which encloses the profile axis PA.The drive surfaces 4 are inclined in a predetermined first plane relative to the profile axis PA in order to create a conicity of the drive surfaces 4 such that they approach the front end – the insertion end – of the outer drive profile 3. From this inclined position, the drive surfaces 4 are additionally tilted in a second plane perpendicular to the predetermined first plane, as can be seen in Figures 1 and 2.

[0036] Convex transition surfaces 5 are provided between the drive surfaces 4, connecting them and lying on common circles in cross-section. The transition surfaces 5 are conically shaped, meaning they are inclined relative to the profile axis PA such that they approach the free insertion end of the outer drive profile 3. The angle of inclination is between 10° and 60° and is approximately 20° in the illustrated embodiment. Figures 10 to 14 show another drive element according to the present invention in the form of a screw 6. The screw 6 has the same structure as the screw 6 shown in Figures 3 to 5 and described above, with the sole difference being that it has four drive surfaces 10 instead of three. The preceding descriptions also apply to this screw 6.

[0037] Specifically, the screw 6 has a screw shank, as shown in Fig. 10, at the rear end of which a screw head 7 is provided with an inner drive profile 8 that is open towards the rear of the screw 6 and defines an insertion opening 9. The inner drive profile 8 defines a profile axis PI that runs coaxially to the longitudinal axis of the screw shank and has three drive surfaces 10 that are concave, i.e., curved towards the interior of the inner drive profile 8.

[0038] The inner drive profile 8 of the screw 6 is designed to be complementary to the outer drive profile 4 of the turning tool 1, so that the drive profiles 3, 8 can be axially connected together and then the drive surfaces 4, 10 come into contact with each other and are clamped together.

[0039] Accordingly, the drive surfaces 9 of the inner drive profile 8, like the drive surfaces 4 of the outer drive profile 3, are inclined relative to the profile axis PI in two mutually perpendicular planes, each enclosing the profile axis PI, as per the invention. The drive surfaces 10 are inclined in a predetermined first plane relative to the profile axis PI to create a conicity of the drive surfaces 4 such that the drive surfaces 10 approach the front inner end of the inner drive profile 8 from the insertion opening 9. From this inclined position, the drive surfaces 10 are additionally tilted in a second plane perpendicular to the predetermined first plane, as can be seen in Figures 3 and 5.

[0040] Convex transition surfaces 11 are provided between the drive surfaces 10, connecting them and lying on common circles in cross-section. The transition surfaces 11 are conically shaped, meaning they are inclined relative to the profile axis PI such that they approach the front, inner end of the inner drive profile 8. The angle of inclination is between 10° and 60° and is approximately 20° in the illustrated embodiment.

[0041] According to the invention, the drive surfaces 4, 10 of the drive profiles 3, 8 are inclined relative to their respective profile axes PA, PI in two mutually perpendicular planes, each enclosing the profile axis, to such an extent that torque transmission from the driving rotary tool 1 to the driven screw 6 is possible in one direction of rotation, but prevented in the other direction. Specifically, the inclination of the drive surfaces 4, 10 results in forces being generated during torque transmission that press the drive profiles 3, 8 of the two drive elements against each other, while in the other direction of rotation, forces are generated that separate the two drive profiles 3, 8 from each other, i.e., push them axially apart.

[0042] I Turning tool

[0043] 2 Tool shaft

[0044] 3. Outer carrying profile

[0045] 4 Drive surfaces of the outer drive profile 5 Transition surfaces of the outer drive profile 6 Screw

[0046] 7 screw head

[0047] 8 inner carry-on profile

[0048] 9 insertion opening

[0049] 10 Drive surfaces of the inner drive profile II Transition surfaces of the inner drive profile

Claims

REQUIREMENTS 1. A drive element comprising an outer drive profile (3) defining a profile axis (PA) and having several concave drive surfaces (4) arranged uniformly around the profile axis (PA), i.e., curved towards the interior of the drive profile (3) and in particular towards the profile axis (PA), between which planar or convexly curved transition surfaces (5) are provided, characterized in that the drive surfaces (4) are each inclined in two planes which enclose the profile axis (PA) and are perpendicular to each other, relative to the profile axis (PA) such that that the drive surfaces (4) of the profile axis (PA) approach a front insertion end of the outer drive profile (3) and that when the outer drive profile (3) of the drive element engages with a complementary inner drive profile (8) of another drive element, torque is transmitted from the driving drive element to the driven drive element via the interaction of the drive surfaces (4, 10) in one direction of rotation of a driving drive element about the profile axis, while in the other direction of rotation the interaction of the drive surfaces (4, 10) causes an axial displacement of the driven drive element in order to disengage the drive profiles (3, 8).

2. Drive element according to claim 1, characterized in that the drive surfaces (4) each have the basic shape of a cylindrical shell section which is inclined in both planes relative to the profile axis (PA), or each have the basic shape of a rectangle which is inclined in both planes relative to the profile axis.

3. Drive element according to claim 1 or 2, characterized in that the drive surfaces (4), in particular the longitudinal directions of the drive surfaces (4) each enclose an angle with a plane perpendicular to the profile axis which is between 20 and 70°, in particular between 30 and 60° and preferably 45 ± 5°.

4. Drive element according to one of the preceding claims, characterized in that the drive surfaces (4) of the outer drive profile (3) are designed such that the drive surfaces of a complementarily designed inner drive profile can be brought into contact with them in a planar and force-fit manner.

5. Drive element according to one of the preceding claims, characterized in that the transition surfaces (5) are inclined relative to the profile axis (PA) such that they approach the profile axis (PA) towards a front insertion end of the outer drive profile (3), wherein, in particular, the angle of inclination is at least 10°, in particular at least 20° and preferably at least 30° and / or at most 60°, in particular at most 50° and preferably at most 45°, wherein the angle is preferably 45 ± 5°.

6. Drive element according to one of the preceding claims, characterized in that the drive element is designed as a rotary tool (1), in particular as a screw bit.

7. Drive element comprising an inner drive profile (8) defining a profile axis (PI) and having several concave drive surfaces (10) arranged uniformly around the profile axis (PI), i.e. curved towards the interior of the drive profile (8) and in particular towards the profile axis (PI), between which planar or convexly curved transition surfaces (11) are provided, characterized in that the drive surfaces (10) are each inclined in two planes which enclose the profile axis (PI) and are perpendicular to each other, such that that the drive surfaces (10) of the profile axis (PI) approach a front, inner end of the inner drive profile (8) starting from an insertion opening (9) of the inner drive profile (8) and that when the inner drive profile (8) of the drive element engages with a complementary outer drive profile (3) of another drive element, torque is transmitted from the driving drive element to the driven drive element via the interaction of the drive surfaces (10, 4) in one direction of rotation of a driving drive element about the profile axis, while in the other direction of rotation the interaction of the drive surfaces (10, 4) causes an axial displacement of the driven drive element in order to disengage the drive profiles (3, 8).

8. Drive element according to claim 7, characterized in that the drive surfaces (10) each have the basic shape of a cylindrical section which is inclined in both planes relative to the profile axis (PI), or each have the basic shape of a rectangle which is inclined in both planes relative to the profile axis (PI).

9. Drive element according to claim 7 or 8, characterized in that the drive surfaces (10), in particular the longitudinal directions of the drive surfaces (10), each enclose an angle with a plane perpendicular to the profile axis (PI) which is between 20 and 70°, in particular between 30 and 60° and preferably 45 ± 5°.

10. Drive element according to one of claims 7 to 9, characterized in that the drive surfaces (10) of the inner drive profile (8) are designed such that the drive surfaces of a complementarily designed outer drive profile can be brought into contact with them in a planar and force-fit manner.

11. Drive element according to one of claims 7 to 10, characterized in that the transition surfaces (11) are inclined relative to the profile axis (PI) such that they approach the profile axis (PI) from an insertion opening of the inner drive profile (8) to a front, inner end of the inner drive profile (8), wherein, in particular, the angle of inclination is at least 10°, in particular at least 20° and preferably at least 30° and / or at most 60°, in particular at most 50° and preferably at most 45°, wherein the angle is preferably 45 ± 5°.

12. Drive element according to one of claims 7 to 11, characterized in that the drive element is designed as a screw.

13. Method for connecting two components in a rotationally fixed manner, in particular a screw and a turning tool, wherein one of the components is designed as a drive element with an outer drive profile and the other component as a drive element with an inner drive profile, wherein the drive profiles of the two components are axially connected together to create a rotationally fixed connection between the two components, characterized in that one component is designed as a drive element according to one of claims 1 to 6 and the other component according to one of claims 7 to 12 and the drive profiles of the drive elements are designed to be complementary to each other such that the drive surfaces of the components come into planar contact with each other when the drive profiles are axially connected together, so that a force-fit and / or clamping connection, by means of which the components are axially connected to each other, is created between the components.

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