CN217783989U - Fastening assembly - Google Patents

Abstract

The utility model provides a fastening assembly, including fastening element, this fastening element includes: a head portion engageable by a tool; the fastening element having a first end and a second end, the first end having a protruding cylindrical portion with a diameter smaller than a diameter of the head portion; and a flange portion having an outer diameter greater than the diameter of the cylindrical portion, wherein the flange portion has a diameter less than the diameter of the head portion, the flange portion having a surface facing the first end, the surface surrounding a central axis of the fastening element, the fastening assembly further comprising at least one locking washer, wherein the locking washer has a first inner diameter at the first end face, wherein a distance D between an underside of the locking washer and a start of a thread on the fastening element satisfies the following relationship: d > 2P where D is defined from the underside of the locking washer when the locking washer is in a position closest to the head portion, where P is the pitch of the thread.

Description

Fastening assembly

Technical Field

The present application relates to a fastening assembly and a method for producing a fastening assembly.

Background

Wedge-shaped locking washers have long been known.

Washers for locking purposes are previously known and usually comprise a central hole for the shank. Typically, this arrangement is a number of different variations. One particular arrangement is a lock washer that includes teeth on one side and a cam (cam) on the other side. The teeth may be generally described as being shaped so that they can engage with the surface of a screw head, nut or element to be attached. One possible shape is a slanted pyramid shape. The teeth extend radially on the surface of the lock washer. The other side of the known locking washer may have a cam pattern. The cam pattern can be generally described as an inclined wedge surface, where the angle of inclination of the cam should be greater than the pitch of the screw thread of the screw. The cam pattern extends radially. These locking washers are used in pairs, where the pair consists of two identical washers, but in use the cams are adjacent to each other and the teeth of the corresponding other side of the washers face away from each other. This arrangement provides a very safe and reliable attachment, applied in the correct way, and using a suitably stiff element to be attached and a washer for locking the screw joint. This type of gasket is described, for example, in document DE 2 413 760.

A washer intended for use in pairs is also described in another document US 2008/0014046 A1.

It will be appreciated from the above that the locking washer pair, when separated into two separate washers, can generally be applied in any configuration of joint. Thus, a nervous or inexperienced user may press the cam of the first washer against the friction means (e.g. teeth) of the second washer, thus losing the wedge-locking effect of the joint. To solve this problem, usually wedge-shaped locking washers can be releasably attached to each other in the correct configuration, for example by glue. Since glue cannot fully fix the washers together, the washers can still be separated from each other since the wedge locking effect relies on the cams being able to slide over each other. Thus, an inexperienced user may separate the washer and apply it to the threaded fastener in the wrong configuration.

The ISO standard ISO10644 gives the standard for washers for screws.

It is known to apply surface treatments to both fasteners and washers.

SUMMERY OF THE UTILITY MODEL

It is therefore an object of the present invention to address at least some of the above-mentioned deficiencies of the known prior art.

Thus, according to an aspect of the present invention, there is provided a fastening assembly comprising a fastening element, in particular, the fastening element comprising:

a head portion engageable by a tool, the fastening element having a first end,

-the fastening element has a second end,

-the first end has a protruding cylindrical portion having a diameter smaller than the diameter of the head portion, an

-a flange portion having an outer diameter larger than the diameter of the cylindrical portion,

-the flange portion has a surface facing the first end, which surface surrounds a centre axis of the fastening element,

the fastening assembly further comprises at least one locking washer,

wherein the locking washer has a first inner diameter at a first end face,

wherein a distance D between an underside of the lock washer to a beginning of a thread on the fastening element satisfies the following relationship:

D>2*P

wherein D is defined from the underside of the locking washer when the locking washer is in a position proximate the head portion, wherein P is the pitch of the thread.

By having a distance D that meets this criterion, the washer and the screw itself can be surface treated by applying the washer to the screw. The surface treatment product can be sufficiently accessible to treat both the screw and the washer in the same operation. Free movement of the washer on the fastening element is ensured, facilitating surface treatment operations of both the fastening element and the washer. Furthermore, by allowing this distance D to be provided, the threads are effectively prevented from interacting with the lower washer when the fastening assembly is tightened.

According to a further aspect, the locking washer has a second inner diameter at a second end face opposite the first end face, wherein the first inner diameter is smaller than the second inner diameter.

Advantageously, a locking washer will be obtained: it is possible to be more flexible in its use and the guiding of the locking washer to the shank of the fastening element can be designed precisely to a smaller diameter.

According to a further aspect, the fastening element comprises an engagement portion on the cylindrical portion, wherein,

-the diameter of at least a first part of the engagement portion is larger than the outer diameter of the cylindrical portion,

-wherein the diameter of the engagement portion is smaller than the outer diameter of the flange portion,

-the first part of the engagement portion is located at a distance from the surface of the flange portion facing the first end,

-wherein the flange portion is separated from an underside surface of the head portion in an axial direction by a distance,

wherein, if the locking washer is applied with the first inner diameter facing the engagement portion, the locking washer is prevented from reaching the surface of the flange portion by engagement of the first end face with the engagement portion at a first portion of the engagement portion,

-wherein the flange portion is separated from an underside surface of the head portion in an axial direction by a distance.

The advantage of the above solution is that the locking washer is not installed incorrectly. In particular, it is not possible to position the first washer incorrectly on the fastening element. That is, the cam of the first washer is seated against the fastening element surface on the flange portion. The engagement portion will alert the user that the washer has been mounted in the wrong orientation by providing a gap between the washer and the surface of the flange member. Thus, the user will be prevented from tightening the joint before being aware of his mistake, or worse, without being aware of his mistake at all. Furthermore, by applying a distance between the flange portion and the underside of the head portion, this provides a dedicated surface to which the locking washer can engage when correctly mounted, and the underside of the head portion therefore never engages. This means that the underside of the head portion can be constructed in any way, so that the underside of the head portion can be constructed more freely. Furthermore, the flange portion may be better adapted to the engagement of the locking washer. Thus, it may be implemented by different structures of the underside of the flange portion and the head portion. For example, a friction enhancing coating may be used on the flange portion, rather than on the underside of the head portion.

According to a further aspect, there is a relation between the first and second inner diameters of the locking washer, the thickness of the locking washer, the distance between the first part of the engagement portion and the surface of the flange portion, such that:

-said second inner diameter facing said surface of said flange portion when said locking washer is applied on said cylindrical portion of said fastening element,

-the second end face of the locking washer is capable of parallel contact with the surface of the flange portion, such that when the locking washer is applied in this direction, the diameter of the first part of the engagement portion is smaller than the diameter at a point on the inner periphery in the axial direction of the locking washer facing the first part of the engagement portion.

Thus, when the washer is applied correctly, no gaps between the fastening components occur.

According to a further aspect, the fastening assembly comprises two locking washers, and thus the distance D is measured from the underside of the locking washer located closest to the start of the thread.

According to a further development, the two locking washers are constructed in the same way.

An advantage of this arrangement is that the second locking washer is easier to manufacture.

According to a further development, the two locking washers are differently configured, wherein the first locking washer has a first and a second inner diameter which are not equal, wherein the second locking washer has a cylindrical inner diameter which is equal to the smaller first inner diameter.

According to a further aspect, the locking washer includes a wedge-shaped locking cam on the first end face.

According to a further aspect, the engagement portion is provided in the form of a circular protrusion, which surrounds the cylindrical portion.

The advantage of this improvement is that the gasket engages evenly around the cylindrical portion.

According to a further aspect, the engagement portion has a flat upper surface, the distance to the surface of the flange portion also having a perpendicular surface extending to the surface of the flange portion, or a beveled transition, or a convex radius transition or a concave transition.

The advantage of this design is that the gasket will bear very firmly against the engagement portion when mounted incorrectly, so that a user trying to force the gasket against the surface of the flange portion cannot overcome the engagement portion with force. Furthermore, the flat surface ensures that a wrongly mounted washer will lie substantially parallel to the surface of the flange portion, thereby giving a uniformly formed gap with good notification to the user. Furthermore, the different shape of the transition portion between the engagement portion and the flange portion may provide the advantage of the function of the fastening element. The beveled transition will increase strength and prevent sharp edge braking, which may occur if there is a vertical surface substitution. The convex transition will help to prevent any sharp edges that might cut the user when applying the fastening element, as well as the concave transition.

According to a further aspect, the engagement portion is provided in the form of a ramp extending circumferentially around the cylindrical portion and from the surface of the flange portion to the cylindrical portion.

The bevel is simple to manufacture.

According to a further aspect, the surface of the flange portion facing the first end has a cam for engagement with a wedge-shaped locking washer having a corresponding cam.

For the cam on the fastening element, one washer is sufficient.

According to a further aspect, the flange portion has a diameter smaller than a diameter of the head portion.

If the flange portion is made smaller than the head portion, the flange portion can easily accommodate six-sided fastening element heads.

According to a further aspect, the head portion is a hexagonal head, or a circular head comprising a quincuncial groove, or a circular head comprising a hexagonal groove.

According to a further aspect, wherein the fastening element is a screw.

The advantage is that the present disclosure can implant a variety of screws. Which extends the area in which the fastening assembly can be applied.

According to another aspect of the present invention, there is provided a method for producing a fastening assembly, comprising the steps of,

-cold forming of the fastening element blank,

cold forming one or more washers, the inner diameter of which fits into the cylindrical portion of the fastening element,

-mounting the washer or washers to the fastening element blank,

-forming a thread on the fastening element, thereby increasing the diameter of the top of the thread to a diameter larger than the inner diameter of the one or more washers,

-controlling the formation of the thread such that the distance D between the underside of the locking washer to the beginning of the thread on the fastening element satisfies the following relation:

D>2*P

wherein P is the pitch of the thread, wherein D is defined from the underside of at least one of the locking washers when the locking washer is in its position closest to the head portion of the fastening element, wherein P is the pitch of the thread,

-surface treating the fastening assembly when installed.

The method provides a particularly effective way of surface treating the assembly of the fastening element and the one or more locking washers.

According to a further method for producing a fastening assembly, wherein the fastening element is a screw.

An advantage is that the screw is surface treated together with one or more locking washers, providing a good starting point for the screw.

Drawings

Fig. 1 discloses a locking washer according to the present disclosure.

Fig. 2 discloses a fastening element according to the present disclosure in the form of a screw.

Fig. 3 discloses a fastening assembly with a screw according to fig. 2.

FIG. 4 discloses a fastening element and a fastening assembly according to the present disclosure.

Fig. 5 discloses a fastening assembly with a pair of properly attached locking washers.

Fig. 6 discloses a fastening assembly with a pair of properly attached locking washers when the first washer is engaged with the flange portion.

Fig 7 discloses a section of the fastening assembly according to fig 5.

Fig 8 discloses a section of the fastening assembly according to fig 6.

FIG. 9 discloses a fastening assembly according to the present disclosure wherein the upper lock washer is installed incorrectly.

Fig. 10 discloses the fastening assembly according to fig. 9 in cross section.

Fig. 11 discloses a fastening element according to fig. 2 in the form of a screw.

Fig. 12 discloses a method according to the invention.

Fig. 13 discloses a fastening element with a washer, wherein the fastening element has an inner engagement surface.

Fig. 14 discloses an enlarged view of the upper right portion of the fastening element of fig. 13.

Detailed Description

Fig. 1 and 3 disclose a first locking washer 17 and a second locking washer 18 used in pairs. The locking washer generally comprises: an engagement means 31, which may be in the form of ratchet teeth or a rough surface on one side; and engagement means in the form of a cam 22 on the other side.

The engagement means 31 of the first locking washer 17 engage with the head portion 6 of the fastening element. As will be explained below, in particular the flange portion 4 of the head portion of the fastening element 1. The fastening element 1 has a thread 21 engaging with a threaded element. The pitch angle β (fig. 3) of the thread 21 is always smaller than the wedge angle α (fig. 1) of the cam of the locking washer. Thus, when unscrewing the fastening element 1, the cams 22 of the respective first and second locking washers 17, 18 will slide relative to each other and, due to the difference in thread pitch, they will try to expand the joint instead of due to the thread. With this arrangement, the joint is securely locked.

The engagement means 31 in the form of teeth may have any general configuration so as to be able to engage. One configuration is an inclined pyramid shape, where the inclined teeth engage the screw head or workpiece with their steeper sides. Other configurations of teeth are contemplated. For example, the teeth may have the same configuration of a pyramidal shape. The teeth may also have a trapezoidal shape. It is important that the teeth have a hardness that is superior to that of the screw head and the workpiece. The reason is that: to achieve the locking function, the teeth must be able to engage with the material they are adjacent to. Otherwise, the teeth may collapse due to momentum or slide over harder adjacent surfaces when the fitting is tightened. Thus, when tightening the joint, the first locking washer 17 moves together with the fastening element 1 and the second locking washer 18 remains stationary on the workpiece 35.

The cam 22 may be described as wedge-shaped, see fig. 1 as an example thereof. The cam 22 typically has a relatively steep surface and an inclined surface. Thus, when the respective first and second locking washers 17, 18 are fastened to each other, their respective cams 22 can be positioned adjacent to each other. The locking is achieved by the wedge shape of the cam 22. When the tightened fastening element 1 is loosened, for example by vibration or by the user, the engagement means of the locking washer engage with the head of the fastening element and the already attached element. Thus, the first locking washer 17 seeks to follow the movement of the fastening element 1 in the turning direction, and the second locking washer 18 seeks to be held in place by the respective engagement means 31 engaging with, for example, a workpiece. The cams 22 slide on their inclined surfaces against each other, seeking to extend the screw joint in the longitudinal direction of the fastening element 1, by means of the inclination wedge angle α of the cam surfaces, when sliding in the loosening direction. Such extension locks the joint and prevents the fastening element from loosening. Thus, the cam 22 prevents the first locking washer 17 and the second locking washer 18 from moving in the loosening direction of the screw.

The distinction between a tooth and a cam 22 can be generally described as the tooth not being designed to interact with another serrated surface, while the cams 22 are intended to cooperate with each other on the respective locking washer. And the cam 22 should have a wedge angle of a particular configuration as seen above and in fig. 1. Furthermore, the teeth should be capable of preventing the washer from sliding on the surface against which the teeth abut. Preferably, the teeth should engage the surface against which they bear, so that when unscrewing the joint, the steep surface of the non-uniformly shaped teeth should be opposite to the direction of unscrewing. This means that the steep surface of the tooth should be opposite to the unscrewing direction. This is in contrast to a cam, which should always have its steep surface in the unscrewing direction. The roughened surface instead of the teeth will have the same function as the teeth.

Fig. 2 to 11 and 13 disclose a fastening element 1 in the form of a screw, which is comprised in a fastening assembly 25 as disclosed in fig. 3 to 10. The fastening assembly 25 includes features having a distance D, defined as D, from the underside of the second locking washer 18 to the thread 21, see fig. 7 or 9. The present disclosure relates to distance D to satisfy the relationship:

D>2*P

p is the pitch of the thread 21 of the fastening element 1.

The fastening element 1 typically has a hexagonal head portion 6 so that it can be engaged by a tool, such as a wrench. It should be understood that a hexagonal shape is not mandatory. Screws for allen wrenches with hexagonal slots are also contemplated, see fig. 13 and 14, and other similar arrangements, e.g.

Thus, for socket head wrenches or screwsThe engagement surface 34 of the knife is inside the head portion 6 of the screw. Furthermore, the fastening element has a first end 7 and a second end 8. The first end has a protruding cylindrical portion 3. The cylindrical portion 3 extends from a surface 5 on the flange portion 4 of the fastening element. The cylindrical part 3 is arranged to the fastening element to guide a first locking washer 17 and a second locking washer 18 (see fig. 8) to be used with the fastening element 1. At the transition between the cylindrical portion 3 and the surface 5 of the flange portion 4, a joint portion 2 may be provided. The engagement portion 2 may be shaped with a flat surface 2b transverse to the centre line of the screw, as shown in fig. 3, or the nut of fig. 4. The steeper side of the engagement portion 2 connects this portion to the surface 5 of the flange portion 4. But the portion may be convex, concave or have a beveled transition. The engaging portion 2 must have a larger diameter than the cylindrical portion 3 at least at the first portion 2a. For the purpose of the present invention, the engaging part 2 may of course have other shapes, for example, it may have a beveled shape. Thus, the slope of the engaging portion 2 may extend at an angle from the cylindrical portion 3 to the surface 5 of the flange portion 4. The meaning of the bevel should be interpreted broadly, meaning an inclined surface. The first portion 2a on the engagement portion 2 of the ramp will be an imaginary point where the wrongly mounted locking washer is in contact with the engagement portion 2 of the ramp. See in particular fig. 3 and 11, wherein a first part 2a of a circular transition from the cylindrical part 3 to the joint part is disclosed. This may be a chamfer or the transition of portion 2a +2 to flange portion 4.

The cylindrical part 3 has the further function of guiding a first locking washer 17 and a second locking washer 18 to be applied, see for example fig. 3, 4 or 5. An additional function of the cylindrical portion is to hold the first and second locking washers 17, 18 on the fastening element. Generally, ordinary fastening elements do not hold or secure any washers. But by providing a cylindrical portion 3 the washer can be held on the fastening element 1. Thus, the fastening element and the first and second locking washers 17, 18 can be provided to the user as a unit, wherein the washers are mounted on the fastening element 1 via the cylindrical portion 3. But more importantly, when the user wants to apply the first and second locking washers 17, 18 to the joint, he can first apply the washers to the fastening element 1, so that there is no need to keep the washers in place on the fastening element when assembling the parts to be attached together.

For screws, fig. 3, 5, 6, 7, 8, 9, 10, 11 and 13, 14, the thread 21 is disclosed on the cylindrical part 3 of the screw, see e.g. fig. 3 or 6. The screw has an engagement portion 2 with a flat surface. It will be appreciated that the diameter of the thread 21 is smaller than the diameter of the cylindrical part 3 of the screw, so that the washer can be introduced on the screw without any hindrance.

Fig. 3 to 10 disclose a fastening assembly 25 having a fastening element 1 as described above and further having a first locking washer 17 and a second locking washer 18. In fig. 9 and 10, the first locking washer 17 has been mounted on the screw of the present disclosure in the wrong orientation. Thus, the first locking washer 17 abuts against the flat surface of the engagement portion 2 of the nut with the first diameter 10. This creates a gap 19, which gap 19 prevents the first end face 15 of the first locking washer 17 from reaching the surface 5 of the flange portion 4 of the nut. This gap 19 corresponds to the distance 9 that will occur when the first locking washer 17 is mounted with the wrong end 13 towards the surface 5 of the flange portion 4 of the fastening element 1. In this fig. 6, the second locking washer 18 is correctly applied. However, since the cam 22 of the first locking washer 17 is mounted in the wrong direction, no wedge locking effect occurs.

Fig. 5 to 8 disclose the fastening assembly 25 according to fig. 3 when the first locking washer 17 has been mounted in a correct manner. In this configuration, the first locking washer 17 can be positioned near the surface 5 of the flange portion 4. This is due to the fact that the second diameter 11 of the first locking washer 17 is larger than the diameter of the engagement portion 2, so that the first locking washer 17 can accommodate the engagement portion without substantially touching it. The second locking washer 18 has the same position as in fig. 6. Typically, the cams 22 of the first and second lock washers 17, 18 are in contact in the interface between the two disclosed first and second lock washers 17, 18.

Thus, there is a specific relation between the first diameter 10 and the second diameter 11 of the first locking washer 17, the thickness T of the washer, and the distance between the first portion 2a of the engaging portion 2 and the surface 5 of the flange portion, such that the second end face 16 of the washer can be positioned in parallel contact with the surface 5 of the flange portion 4 when the second diameter is facing the surface 5 of the flange portion 4 when said locking washer is applied on the cylindrical portion 3 of the fastening element, whereby the diameter of the first portion 2a of the engaging portion 2 is smaller than the diameter at the point on the inner periphery in the axial direction of the washer facing the first portion 2a of the engaging portion 2 when the washer is applied in this direction. That is, when the gasket is resting on the surface 5 of the flange portion 4, the diameter at the point of the periphery of the inner bore of the gasket facing the first portion 2a is greater than the diameter of the first portion 2a. Thus, the first portion 2a does not hinder the introduction of the first locking washer 17 if placed in the correct orientation on the cylindrical portion 3. Furthermore, the thickness T of the first locking washer 17 should allow this, and therefore the distance of the first portion 2a from the surface 5 of the flange portion should not be greater than the thickness T of the first locking washer 17.

The first and second locking washers 17, 18 of the fastening assembly 25 are disclosed in fig. 4, 5, 6 to 11, disclosing a first diameter 10 that is smaller than the second diameter 11. Normally, the smaller first diameter 10 is located on the same end side as the cams 22 of the first and second locking washers 17, 18. The engaging means 31 is normally positioned on the other side.

The flange portion 4 should be understood to be of smaller dimensions than the head portion 6. It will be appreciated that the application of the flange portion 4 is to provide a dedicated surface 5 of the fastening element 1, which surface 5 can engage the first locking washer 17. An underside surface 6a of the head portion is provided on the outside of the flange portion 4, see fig. 3 and 11. There is a distance 30 in the axial direction 40 between the flange portion and the lower side surface 6a of the head portion. This provides a gap 41 between the first locking washer 17 and the lower side surface 6a, also when the first locking washer 17 is applied in the correct manner. This has the advantage that the first and second locking washers 17, 18 are at a distance, for example, from the head portion 6 of the fastening element 1, and this will reduce the chance of damaging or moving the first and second locking washers 17, 18 when the fastening element 1 is engaged for tightening or loosening the fastening element 1.

In fig. 13 and 14, a fastening element 1a with an inner engagement surface 34 is disclosed. The flange portion 4 is here at the same level as the lower side surface 6a of the head portion 6. Thus, the flange portion may be integral with the underside surface of the head portion 6. The engaging portions are still applied. The distance 30 of fig. 11 can be removed. Fig. 14 discloses the same distance D as has been discussed and disclosed previously.

The axial direction 40 of the fastening element described above is to be understood as the direction in which the cylindrical part of the screw extends, see for example fig. 3, 11.

Other configurations of the engaging part 2 are conceivable within the scope of the invention, so that for example the engaging part 2 does not have to surround a nut or a screw. It may consist of a part of the protruding engagement part unit surrounding the screw, but with a part where no engagement part is present.

In general, the present disclosure provides a fastening assembly 25 that presents two gaps 19 and 41 when the first and second locking washers 17 and 18 are installed incorrectly, and one gap 41 when installed correctly. The latter gap 41 is smaller than when the locking washer is erroneously mounted. See fig. 9 and 10.

Furthermore, a method for producing a fastening assembly is disclosed, which comprises a step of cold forming of a fastening element blank, see fig. 12.

The fastening element is thus manufactured as a blank, which means without any thread.

Furthermore, there is the step of cold forming a washer or washers, the inner diameter of which is adapted to the cylindrical portion of the fastening element.

Suitably means that the washer has a sufficiently small inner diameter so that the washer can be guided by the cylindrical part of the fastening element. However, the inner diameter is not so large as to push the washer to the side of the cylindrical portion.

In a further step, the washer/washers is/are mounted onto the fastening element blank. This means that at least one washer is mounted to the cylindrical portion in the central hole of the washer.

In a further step, a thread is formed on the fastening element, increasing the diameter of the top of the thread to a diameter larger than the inner diameter of the washer or washers.

Therefore, the thread should provide an increased diameter for the cylindrical portion.

The step of forming the thread involves controlling the formation of the thread such that the distance D between the underside of the washer to the start of the thread on the fastening element satisfies the following relationship:

D>2*P

where P is the pitch of the thread, where D is defined from the underside of at least one washer when the washer is in its position closest to the head portion of the fastening element, where P is the pitch of the thread.

Then, a further step of surface treating the fastening assembly upon installation is provided.

Thus, both the washer and the fastening element are assembled to the fastening assembly and surface treated at the time of assembly. Thus, the surface treatment may be any type of friction reducing, anti-corrosion coating, zinc flake coating, or the like.

Claims (15)

1. Fastening assembly comprising a fastening element (1), characterized in that it comprises:

-a tool-engageable head portion (6), the fastening element (1) having a first end (7),

-the fastening element (1) has a second end (8),

-the first end (7) has a protruding cylindrical portion (3) with a diameter smaller than the diameter of the head portion (6), and

-a flange portion (4) having an outer diameter larger than the diameter of the cylindrical portion (3),

-the flange portion (4) has a surface (5) facing the first end (7) and surrounding a centre axis of the fastening element,

the fastening assembly further comprises at least one locking washer,

wherein the locking washer has a first inner diameter (10) at a first end face (15),

wherein the distance D between the underside of the locking washer to the beginning of the thread (21) on the fastening element (1) satisfies the following relation:

D>2*P

wherein D is defined from the underside of the locking washer when the locking washer is in a position closest to the head portion (6), wherein P is the pitch of the thread (21).

2. The fastening assembly according to claim 1, characterized in that the locking washer has a second inner diameter (11) at a second end face (16) opposite the first end face (15),

wherein the first inner diameter (10) is smaller than the second inner diameter (11).

3. The fastening assembly of claim 2,

the fastening element (1) comprises an engagement portion (2) on the cylindrical portion (3), wherein,

-the diameter of at least a first portion (2 a) of the engagement portion (2) is greater than the outer diameter of the cylindrical portion (3),

-wherein the diameter of the engagement portion (2) is smaller than the outer diameter of the flange portion (4),

-the first portion (2 a) of the engagement portion (2) is located at a distance (9) from the surface (5) of the flange portion (4) facing the first end (7),

-wherein the flange portion (4) is separated from an underside surface (6 a) of the head portion in an axial direction (40) by a distance (30),

wherein the locking washer is prevented from reaching the surface (5) of the flange portion (4) by the engagement of the first end face (15) with the engagement portion (2) at a first portion (2 a) of the engagement portion if the locking washer is applied with the first inner diameter (10) facing the engagement portion (2),

-wherein the flange portion (4) is separated from the head portion underside surface (6 a) in an axial direction (40) by a distance (30).

4. The fastening assembly of claim 3,

-there is a relation between the first inner diameter (10) and the second inner diameter (11) of the locking washer, the thickness (T) of the locking washer, the distance between the first portion (2 a) of the engagement portion (2) and the surface (5) of the flange portion, such that:

-said second inner diameter facing said surface (5) of said flange portion (4) when said locking washer is applied on said cylindrical portion (3) of said fastening element,

-the second end face of the locking washer is capable of parallel contact with the surface (5) of the flange portion (4), so that when the locking washer is applied in this direction, the diameter of the first portion (2 a) of the engagement portion (2) is smaller than the diameter at a point on the inner periphery in the axial direction of the locking washer facing the first portion (2 a) of the engagement portion (2).

5. The fastening assembly according to claim 1 or 2, characterized in that it comprises two locking washers, and that the distance D is thus measured from the underside of the locking washer located closest to the beginning of the thread (21).

6. The fastening assembly according to claim 5, wherein the two locking washers are constructed in the same manner.

7. The fastening assembly of claim 5 wherein the two locking washers are differently configured, wherein the first locking washer has unequal first and second inner diameters, wherein the second locking washer has a cylindrical inner diameter equal to the smaller first inner diameter.

8. The fastening assembly according to claim 1 or 2, wherein the locking washer comprises a wedge-shaped locking cam (22) on the first end face.

9. A fastening assembly according to claim 3 characterized in that the engagement portion (2) is provided in the form of a circular protrusion which surrounds the cylindrical portion (3).

10. A fastening assembly according to claim 3 characterized in that the engagement portion (2) has a flat upper surface, the distance (9) from the surface (5) of the flange portion (4) also having a substantially perpendicular surface extending to the surface (5) of the flange portion (4), or a bevelled transition, or a convex radius transition or a concave transition.

11. A fastening assembly according to claim 3 characterized in that the engagement portion (2) is provided in the form of a ramp extending circumferentially around the cylindrical portion (3) and from the surface (5) of the flange portion (4) to the cylindrical portion.

12. A fastening assembly according to claim 1 or 2, characterized in that the surface (5) of the flange portion (4) facing the first end (7) is provided with cams for engagement with wedge-shaped locking washers with corresponding cams.

13. The fastening assembly according to claim 1 or 2, characterized in that the flange portion (4) has a smaller diameter than the head portion (6).

14. A fastening assembly according to claim 1 or 2 wherein the head portion is a hexagonal head, or a circular head comprising a quincuncial slot, or a circular head comprising a hexagonal slot.

15. The fastening assembly according to claim 1 or 2, wherein the fastening element is a screw.

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