Screw locking washer

Abstract

A screw locking washer with an annular disc body (1) for arrangement between a screw head (61) and a flat surface, with a disc top facing away from the surface, which is provided with a structure (5), characterized in that the structure (5) is provided in an annular section framing the passage (2) of the disc body (1), the outer diameter of which is smaller than the outer diameter of the disc body (1) and which has at least a partially annular elevation at least on its outwardly facing side and is bounded by a recess (4) provided in the disc body that is circumferential at least partially.

Description

[0001] The invention relates to a screw locking washer with an annular washer body for arrangement between a screw head and a flat base according to the preamble of claim 1.

[0002] The purpose of thread lock washers is to counteract loosening and unscrewing effects in screw connections. Loosening effects arise, possibly due to previous loosening effects, from relative movement under the screw head perpendicular to the screw axis and the breathing of the screw thread.

[0003] In order to prevent the screw from loosening, it is known to provide screw lock washers with a structure on their upper side facing the screw head, in particular in the form of knurling, fluting, toothing or ribs. This structure runs radially outwards from the passage of the screw lock washer through which the screw is guided to the outer edge of the screw lock washer. By pressing the raised portions of the structure, which are formed, for example, by ribs or toothing, into the underside of the screw head, a positive connection is achieved which improves the resistance to loosening. In addition, this ensures optimal contact, which is of great importance, for example, in ground fault applications.

[0004] However, the problem with previously known screw lock washers is that the rotational movement of the screw head relative to the washer surface during tightening of the screw leads to material removal. This causes increased residual dirt and even chip formation, which impairs the contact of the screw head with the washer surface. In addition, the scraping effect of the relative movement between the screw head and the washer surface creates bare surfaces both on the side of the screw lock washer facing the screw head and under the screw head itself, which increases the risk of corrosion for both connecting elements. The depressions and elevations of the attached structure, such as coding and serrations, can allow moisture to penetrate to the bare areas, which can lead to creeping, hidden corrosion.

[0005] The invention aims to remedy this situation. The invention is based on the object of providing a screw locking washer of the above type that ensures improved contact of the screw head with the washer surface and reduces the risk of hidden corrosion. According to the invention, this object is achieved by a screw locking washer having the features of the characterizing part of claim 1.

[0006] The invention provides a screw locking washer of the present type which ensures improved contact of the screw head with the washer surface and in which the risk of hidden corrosion is reduced. Because the structure is incorporated in an annular section framing the passage of the washer body, the outer diameter of which is smaller than the outer diameter of the washer body and which has an annular elevation, at least in some regions, at least on its outward-facing side, an annular sealing lip is formed which is compressed by the screw head when the screw is tightened, thereby creating a metallic seal which counteracts the penetration of moisture.Because the annular protrusion is delimited by a recess formed in the washer body, at least in part, it provides a receptacle for displaced material from the sealing lip, thus counteracting any impairment of the screw head's contact with the washer's upper surface. At the same time, the contact surfaces of the screw head's underside and the area of ​​the washer surface that comes into contact with it are roughened during the tightening process, creating a positive connection.

[0007] In this context, a structure is understood to mean any arrangement of elevations and / or depressions, regardless of their shape (e.g., longitudinal, grooved, ribbed, scale-like, or toothed). The elevations and / or depressions do not have to be continuous. The structure can also be formed from individual surface segments arranged circumferentially on elevations and / or depressions.

[0008] Essential to the invention is the arrangement of a sealing lip which is at least partially circumferential, preferably completely circumferential, for sealing off the roughened contact area arranged between the screw head and the washer surface from the environment, as well as an at least partially circumferential recess for receiving displaced material.

[0009] In a further development of the invention, the recess is designed in the form of a groove, preferably with a smooth cross-section. This improves material absorption, particularly in the event of chip formation.

[0010] In an embodiment of the invention, the structure is formed by a knurling, a ribbing, or a toothing, wherein the knurling is preferably designed in the form of a line, a zigzag pattern, or in a scale pattern. This supports the formation of a positive connection between the underside of the screw head and the washer surface.

[0011] In a further embodiment of the invention, an annular raised base is arranged on the top side of the washer, surrounding the passage of the washer body, into the surface of which the structure is incorporated. This prevents weakening of the screw locking washer due to material removal when tightening the screw. Advantageously, the height of the structure corresponds at most to the height of the raised area of ​​the annular section. The maximum height of the structure and also of the raised annular section is preferably between 0.05 mm and 0.5 mm, preferably between 0.03 mm and 0.3 mm.

[0012] In a further development of the invention, the structure has a height that increases radially outward. This promotes the transfer of displaced material from the raised annular section into the recess. Furthermore, this results in increasing contact between the screw head and the structure after the sealing lip forms a metallic seal. Should material abrasion occur during the tightening process, this abrasion remains within the sealed area between the screw thread and the sealing lip.

[0013] In an embodiment of the invention, the washer body has a material thickness of at least 2.0 mm, preferably at least 2.5 mm. This ensures sufficient stability of the locking washer.

[0014] In a further embodiment of the invention, the thread lock washer is made of stainless steel with material number 1.4401 or 1.4301 according to DIN EN 100272:2015-7. These are cost-effective materials with excellent corrosion properties. Using such a commercially available and formable starting material makes it easy to stamp the knurling and achieves good hardening of the thread lock washer's surfaces.

[0015] Further developments and refinements of the invention are specified in the remaining subclaims. An embodiment of the invention is illustrated in the drawings and described in detail below. They show: Fig. 1: the schematic spatial representation of a screw locking washer; Fig. 2: the schematic representation of the screw locking washer from Fig. 1 in plan view; Fig. 3: the schematic representation of the screw locking washer from Fig. 1 in cross section; Fig. 4: the schematic representation of a screw connection with a screw locking washer according to Fig. 1 and Fig. 5: the detailed view of section A from Fig. 4.

[0016] The screw locking washer selected as an exemplary embodiment comprises an annular washer body 1 with a passage 2 for the passage of a screw 6. Concentric to the passage 2, the washer body 1 has an annular base 3 on its upper side, which is surrounded by a groove-shaped depression 4 and which is provided with a structure 5. In the exemplary embodiment, the structure 5 is formed by a toothing whose tooth segments 51 are designed to increase in height radially outwards, whereby an outer raised annular section is formed which forms a raised sealing ring 52. In the exemplary embodiment, the sealing ring 52 has a height of 0.15 mm.

[0017] In Fig.Figure 4 schematically shows a screw connection with such a screw lock washer. A screw 6 is guided through the passage 2, the screw head 61 of which has a diameter larger than the diameter of the recess 4 surrounding the sealing ring 52.

[0018] When the screw 6 is tightened, the screw head 61 is pressed against the outer raised sealing ring 52 of the structure 5, thereby compressing it. The material of the sealing ring 52, which acts as a sealing lip, displaced when the screw 6 is tightened, is conveyed into the circumferential recess 4. A metallic seal is thus formed between the sealing ring 52 and the screw head 61.

[0019] The underside of the screw head 61 thereby increasingly comes into contact with the entire structure 5. Due to the relative movement of the screw head 61 and the structure 5 against which it is pressed, the underside of the screw head 61 as well as the structure 5 are roughened, and a positive connection is formed between the screw head 61 and the washer body 1. Any material removed in this process remains between the thread of the screw 6 and the metallic seal formed by the sealing lip 52. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] DIN EN 100272:2015-7

[0014]

Claims

[1] Screw locking washer with an annular washer body (1) for arrangement between a screw head (61) and a flat base, with a washer upper side facing away from the base, which is provided with a structure (5), characterized by that the structure (5) is introduced into an annular section framing the passage (2) of the disc body (1), the outer diameter of which is smaller than the outer diameter of the disc body (1) and which has, at least on its outwardly directed side, an at least partially annular elevation and is delimited by an at least partially circumferential recess (4) introduced into the disc body. [2] Screw locking washer according to claim 1, characterized by that the recess (4) is designed in the manner of a groove with a preferably edge-free cross-section. [3] Screw locking washer according to claim 1 or 2, characterized bythat the structure (5) is formed by a cording, a ribbing or a toothing, wherein the cording is preferably designed in the form of a line or a zigzag pattern or in the form of scales. [4] Screw locking washer according to one of the preceding claims, characterized by that on the upper side of the disc, an annular raised base (3) is arranged surrounding the passage (2) of the disc body (1), in the surface of which the structure (5) is introduced. [5] Screw locking washer according to one of the preceding claims, characterized by that the height of the structure (5) corresponds at most to the height of the outer raised annular section (52). [6] Screw locking washer according to one of the preceding claims, characterized by that the structure (5) has a height that increases radially outwards. [7] Screw locking washer according to one of the preceding claims, characterized bythat the maximum height of the structure (5) as well as of the outer raised annular portion (52) is between 0.05 mm and 0.5 mm, preferably between 0.03 mm and 0.3 mm. [8] Screw locking washer according to one of the preceding claims, characterized by that the disc body (1) has a material thickness of at least 2.0 mm, preferably at least 2.5 mm. [9] Screw locking washer according to one of the preceding claims, characterized by that it is made of stainless steel with material number 1.4401 or 1.4301 in accordance with DIN EN 10027-2:2015-7.

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