TENSION RELIEF GUARD

Description

[0001] The invention relates to a strain relief grommet made of an elastic material for receiving at least one cable in at least one axial through-opening, which is hinged via a slot and at least indirectly connected to an outer surface of the strain relief grommet. The invention further relates to a cable gland for assembly with such strain relief grommets, having a frame open on one side and a frame cover.

[0002] Hinged strain relief grommets suitable for accommodating pre-assembled cables with connectors or similar fittings are known in the prior art. These typically consist of an elastic material, such as an elastomer. They can be opened along a slot to provide a lateral access opening. This allows a cable to be inserted into the opening, even if, for example, connectors or similar fittings are located on both ends. The strain relief grommet is then folded closed, tightly enclosing the cable. When crimped, it is so tightly secured that, in addition to sealing, strain relief is also achieved. The folded strain relief grommet is then inserted, for example, into a frame or mounting element and crimped in place by closing this frame or mounting element.This ensures close contact between the strain relief sleeve material and the outer sheath of the cable, while simultaneously sealing the slot securely and reliably. This results in excellent strain relief and a superior seal.

[0003] In practice, reliable strain relief and sealing now require a strain relief grommet that matches the respective cable diameter. Strain relief grommets are therefore available on the market in various diameters, particularly in 1 mm increments. In practice, the cable corresponding to the nominal diameter is inserted into the appropriate strain relief grommet. This ensures good strain relief and sealing. Tolerances within the cable and minor diameter deviations of up to 1 mm can be compensated for by the elastic material, especially if sufficient pressure can be applied when closing the frame that houses the strain relief grommet. This is particularly true if the frame consists of parts that are screwed together during closure.However, deviations of more than 1 mm often lead to leaks in practice and, especially if the cable diameter is too small compared to the nominal diameter of the strain relief sleeve, to the risk of insufficient strain relief of the cable.

[0004] As an alternative, a floating cable mounting in a grommet exists in practice. This method serves solely to seal a cable entry and provides no strain relief, or at least none sufficient for practical applications. In these setups, which are shown, for example, in EP 1 498 994 B1, a correspondingly thin, highly elastic membrane is inserted into the opening through which the cable passes. By deforming the membrane, for example by folding in the direction of the cable's travel or by elastically deforming the membrane material by yielding to the cable's diameter, an acceptable seal can be achieved for relatively large cable diameter ranges.As already mentioned, the problem is the strain relief for the cable, which cannot be achieved in practice, on the one hand, and the fact that if the cable is pulled accordingly, there is a risk of damaging the membrane, so that the seal is no longer guaranteed.

[0005] By using areas of different elasticity, for example lower elasticity in the area of ​​the slot, as protected in DE 103 34 996 B4, the problem regarding sealing can be partially counteracted, but a tensile relief relevant for practical purposes cannot be achieved via such grommets with a membrane.

[0006] EP 0 514 174 A1 shows a cable gland with several sealing lips arranged one behind the other in the direction of cable travel. It can be opened for inserting pre-assembled cables.

[0007] DE 20 2012 101 639 U1 shows a feedthrough housing with cable glands.

[0008] WO 2011 / 042128 A2 shows a hinged cable grommet with a curved shape to its inner contour.

[0009] The object of the present invention is to further develop a strain relief grommet, as is known in principle from the prior art described above, in such a way that it becomes more flexible with regard to its use with different diameters. Furthermore, it is an object of the present invention to further develop a cable gland for assembly with such strain relief grommets in such a way that it is particularly easy and efficient to handle.

[0010] This problem is solved by a strain relief grommet with the features of claim 1 and by a cable gland with the features of claim 9. Advantageous embodiments and further developments are described in the respective dependent subclaims.

[0011] The strain relief grommet according to the invention, like strain relief grommets in the prior art, is made of an elastic material. It has at least one through-opening for receiving at least one cable. This through-opening is connected to an outer surface of the strain relief grommet via a slot. To receive multiple cables, several through-openings may be provided. Each of these multiple through-openings can be hinged open via a slot to an adjacent through-opening and is indirectly connected to the outer surface of the strain relief grommet via this slot, or preferably is connected directly to the outer surface of the strain relief grommet via the slot. The strain relief grommet will typically have one through-opening, two adjacent through-openings, or four evenly spaced through-openings. Ideally, each of these through-openings has a slot for hinged opening, which extends to the outer surface.In the case of two adjacent passage openings, it is - as mentioned - also conceivable that only one of the passage openings is connected to the outside via a slot and this passage opening is then connected to the other adjacent passage opening via another slot.

[0012] It is provided that each of the through-openings has at least two strain relief sections of different cross-sections in the axial direction, arranged eccentrically to each other.

[0013] According to the invention, it is further provided that the strain relief section with the smallest cross-section of the through-opening comprises at least 10%, preferably at least 15%, and particularly preferably at least 20% of the axial length of the respective through-opening. This design of the strain relief section with the smallest cross-section of the through-opening, with a comparatively large width of at least 10% of the total thickness of the strain relief sleeve or the corresponding axial length of the respective through-opening, ensures that even the area with the smallest cross-section is sufficiently thick to guarantee adequate strain relief for practical purposes, in addition to a good seal. The strain relief section with the smallest cross-section is therefore deliberately not designed as a type of membrane, but has a much greater width than such a membrane would have.

[0014] In practice, it has been shown that, for example, with a nominal diameter of approximately 5 mm and a design with at least two strain relief sections of different cross-sections (e.g., 5 mm in the area of ​​the smallest cross-section and 7 mm in the area of ​​the larger cross-section), it is possible to accommodate cables with diameters ranging from 5 to approximately 8 mm via the strain relief sleeve, ensuring both good strain relief and a very good seal. For example, if a cable with a nominal diameter of 5 mm is inserted, it is reliably clamped and sealed in the area of ​​the strain relief section with the smallest cross-section. In the area of ​​the strain relief section with the larger cross-section, an annular gap remains around the cable, which is harmless.If a cable with a diameter of, for example, 7 or 8 mm is inserted, the strain relief section with the smallest cross-section is able to deform sufficiently due to the elasticity of the material to allow the cable to pass through it. However, the resulting deformation will be so great that a reliable seal between the cable and the strain relief grommet is no longer guaranteed. In the area of ​​the other strain relief section, which, ideally, is located on the opposite surface of the strain relief grommet when there are two sections, a sufficient seal is achieved, thus ensuring the overall tightness of the assembly remains intact.To prevent moisture from penetrating between the cable and the strain relief grommet, the orientation of the strain relief grommet during installation should ideally be chosen so that the strain relief section that better matches the nominal diameter of the cable is always facing outwards, in order to reliably guarantee a tight seal in every case.

[0015] Compared to prior art designs, a much greater variety of usable cable diameters is possible within a single strain relief grommet while maintaining strain relief and sealing up to protection class IP65. Instead of providing strain relief grommets in millimeter increments, for example, a cable diameter range of 2 to 15 mm can be covered with only five to seven different strain relief grommets instead of thirteen. This significantly reduces the required tooling costs and the number of strain relief grommets a worker needs to carry during assembly, making the use of the strain relief grommets according to the invention highly efficient.

[0016] To seal the aforementioned annular gap, at least one of the through-openings in the area of ​​at least one of the strain relief sections with a larger cross-section may be provided with a sealing lip. Such a sealing lip, which itself does not form a strain relief section but is too thin for that purpose, may also have a small cross-section or an even smaller cross-section than that of the strain relief section with the smallest cross-section. The strain relief and primary sealing occur between the strain relief section with the smaller cross-section, appropriate for the cable, and the cable itself. The sealing lip serves only to roughly seal the annular gap to prevent the accumulation of debris and moisture in its area.

[0017] Alternatively, it would also be conceivable to provide an additional strain relief section with the required width of at least 10% instead of the sealing lip, so that there would be a strain relief section with a small cross-section on the outside of the passage opening and at least one strain relief section with a larger cross-section in between.

[0018] The invention provides that the at least two strain relief sections of different cross-sections are arranged such that their outer circumferences merge directly into one another on the slot side. In the axial direction, they thus follow each other directly on the slot side, so that the respective outer diameters of the strain relief sections overlap in the area of ​​the slot in the form of a straight, continuous transition.

[0019] The slot's path, both axially and perpendicularly, need not be linear; it can also exhibit a wavy or stepped profile. However, if it is linear in the axial direction, then the strain relief sections of different cross-sections on the slot's side can be essentially aligned.

[0020] According to the strain relief sleeve according to the invention, a transition area is arranged between at least two strain relief sections of different cross-sections, connecting the adjacent strain relief sections. Such a transition area allows for a certain degree of design and adaptation. For example, according to an advantageous embodiment of the idea, this transition area can very simply be formed as a step or a slope on its side facing away from the slot. On the side facing the slot, the aligned circumferences are linear anyway, so no geometrically shaped transition area is required there. The step is a particularly simple design, especially when several strain relief sections of different cross-sections are arranged in a stepped sequence.In practice, however, this can lead to significant deformation of the material in the transition area, potentially impairing its sealing properties. Therefore, it may be advisable to use a slope instead of a step, which offers improved functionality.

[0021] According to another highly advantageous embodiment of the transition area, it can also be designed as a continuous transition. Such a continuous transition, running from the level of one strain relief section to the level of the other adjacent strain relief section, can largely eliminate the problem of undesirable material deformation. However, according to yet another highly advantageous embodiment, the transition area can also be designed as a curve that transitions continuously into one strain relief section and, via an edge, into the other strain relief section.Such a design, in which the transition to the strain relief section with the larger cross-section is continuous and to the section with the smaller cross-section occurs via an edge, ensures secure contact between the strain relief section with the smaller cross-section and the cable, thus guaranteeing ideal strain relief. The transition via an edge allows the material of the strain relief section with the smaller cross-section to flex sufficiently when a cable with a larger cross-section is inserted. Simultaneously, the continuous transition to the cross-section of the other strain relief section prevents undesirable deformation of the material in this section, thus ensuring a high degree of tightness.This design, which can, for example, have an exponential or parabolic curve, is therefore a very good compromise between strain relief on the one hand and sealing on the other.

[0022] According to a further embodiment of the idea, each of the through-openings can also be provided with at least three strain relief sections of different cross-sections, arranged axially in order of their cross-sectional size. Such a configuration with three strain relief sections of different cross-sections further increases the flexibility of the strain relief grommet. In the manner described above, a reliable seal can thus be achieved in either the first, second, or third section. The sections follow one another in ascending or descending order according to their cross-sectional size, so that the section best suited to the cable diameter provides the reliable seal, and the other sections, despite significant deformation and / or a remaining annular gap, do not adversely affect the functionality of the strain relief grommet.

[0023] The elastic material from which the strain relief grommet according to the invention can be manufactured is, according to an advantageous embodiment of the idea, designed with a Shore hardness of up to 100 Shore A, preferably 30 to 90 Shore A. In particular, a material in this range of Shore hardness is ideally suited to achieve the described properties and thus to realize a reliable seal and strain relief of cables with diameter differences of, for example, 2 to 3 mm and a nominal diameter of the strain relief grommet of, for example, 5 mm.

[0024] When using a strain relief grommet with only one opening, a further highly advantageous embodiment of the concept allows the central axis of the strain relief section with the smallest cross-section to be positioned centrally within the grommet. In practice, this means that the strain relief section with the larger cross-section is positioned offset outwards from the slot. This results in a thinner material on the side of the strain relief grommet opposite the slot. The strain relief grommet can thus be ideally deformed around the circumference of the cable, enabling a reliable seal to be achieved with minimal pressure.

[0025] A cable gland for assembly with strain relief grommets comprises a frame open on one side, which is essentially U-shaped with one or more chambers separated by intermediate webs, each chamber designed to accommodate at least one strain relief grommet. The strain relief grommets, along with the cables inserted into the hinged grommets, can be placed in this frame. The frame, with one or more chambers arranged side by side in an essentially U-shape, is then closed with a frame cover. In the assembled state, the frame cover presses the at least one strain relief grommet into the at least one chamber. Thus, when the cover is closed, the design presses the strain relief grommet in a direction perpendicular to the axial direction of the at least one through-hole.This results in the slot in the strain relief grommet being compressed, ultimately sealing both the slot and the opening around the inserted cable. The frame cover can, for example, be screwed onto the frame. This allows for comparatively high compression forces when crimping the strain relief grommets, ensuring a good seal even if the cable diameters do not perfectly match the nominal diameters of the openings.

[0026] In practice, screwing the frame cover on is often time-consuming, so, according to an advantageous further development of the idea, the frame cover is snapped to the frame. The locking of the frame cover and the frame can preferably be achieved by locking elements that can be connected between the frame and the frame cover by pressing the frame cover onto them. Such locking elements, for example, locking tabs on the frame cover that extend beyond the frame on the outside, are particularly simple and efficient for allowing the frame cover to be pressed on by hand and automatically connected upon contact. With a suitable design, these locking elements can be lifted again, for example, manually or with the aid of a tool such as a small screwdriver or similar, so that the frame cover can also be removed again if necessary.

[0027] In practice, it has been shown that the force required to snap the frame cover and frame into place is correspondingly limited, as the frame cover is typically only snapped into place manually. The compressive forces required to achieve a seal are therefore much lower than with a screwed-on frame cover. Even with these relatively low compressive forces from manually snapping the frame cover on, the strain relief grommets according to the invention still provide a sufficient seal for different cable diameters, which may vary by, for example, 2 to 3 mm within the same grommet, in order to achieve the corresponding protection classes, such as IP65. Ideally, in the assembled state, the slots of the strain relief grommets run parallel to the largest dimension of the frame cover.The frame cover is therefore attached perpendicular to the orientation of the slots in order to reliably press the two opposing surfaces of the slots together when attaching it.

[0028] A further advantageous development of the idea provides that the frame cover and the frame have corresponding interlocking elements which ensure the desired width of the frame or at least one chamber when the frame cover and frame are joined. Such interlocking elements, for example conical pins and corresponding receiving openings between the frame cover and the frame, ensure that a constant width is achieved after assembly.This ensures a relatively even distribution of pressure over the entire longest dimension of the frame cover, so that, for example, the frame does not remain bulged in the middle and consequently less pressure acts on the strain relief grommets positioned there than in the edge area, as would be the case if the legs of the U were to run diagonally inwards and the frame cover were thus "bent upwards".

[0029] Advantageous further developments and designs of the strain relief grommets and / or the frame provided with them also result from the exemplary embodiments, which are described in more detail below with reference to the figures.

[0030] The figures show: Figs. 1-4 show a possible embodiment of a strain relief grommet according to the invention with a through-opening in a three-sided view and in a sectional view; Figs. 5 and 6 show a schematic representation analogous toFig. 4 with inserted cables of different diameters; Fig. 7 shows an alternative possible embodiment of a strain relief grommet according to the invention in a sectional view analogous to that in Fig. 4 Figs. 8-13 show further different configurations of the through-opening; Fig. 14 shows an alternative embodiment of a strain relief; Figs. 15-20 show a further alternative embodiment of a strain relief grommet with four through-openings; Fig. 21 shows a further alternative embodiment with two through-openings; Figs. 22 and 23 show strain relief grommets in a cable gland for mounting on a control cabinet in a first embodiment; Figs. 24-26 show strain relief grommets in an alternative embodiment of the cable gland; Fig. 27 shows a strain relief grommet in a further alternative embodiment of the cable gland; and Fig. 28 shows a strain relief grommet in yet another alternative embodiment of the cable gland.

[0031] In the presentation of the Figure 1 A strain relief grommet 1 can be seen in a front view. In the illustration of the Figure 2 A side view is visible, in the representation of the Figure 3 a rear view of the same strain relief grommet 1. In Figure 4 is a section according to line IV - IV in Figure 1 The strain relief grommet 1 shown here has a through-opening, designated 2, for receiving a cable. The through-opening is connected to one of the outer surfaces 4 of the strain relief grommet 1 via a slot designated 3. The strain relief grommet 1, which is to be made of an elastomeric material with a Shore hardness of up to 100 Shore A, preferably 30 to 90 Shore A, can be opened along the slot 3 to allow pre-assembled cables to be inserted into the through-opening 2. Figures 1 to 4Cables 20 (not shown), i.e., cables 20 that already have a connector or similar fitting, can be inserted. The strain relief grommet 1 with an inserted cable 20 is then typically crimped into a frame 8 or a receiving element to achieve strain relief of the cable 20 in the through-opening 2 and to ensure a reliable seal. This is known in principle from the prior art and will be explained later in more detail with regard to the use of a frame 8 with such strain relief grommets. Figures 19 described below. The strain relief grommet 1, predominantly rectangular or square in shape, can also have any other outer contour; likewise, the through-opening 2 does not have to be circular, as shown purely by way of example in Figure 25 can be seen.

[0032] In the presentation of the Figure 4 is a section along line IV - IV in Figure 1This section shows the through-opening 2, which contains a first strain relief section, designated 51, of a first cross-section, and a second strain relief section, designated 52, of a second cross-section, which is smaller than the cross-section of strain relief section 51. The central axes of the exemplary round cross-sections of the through-opening 2 and its strain relief sections 51 and 52 run parallel and eccentrically to each other, i.e., they are spaced apart by a distance x. The respective outer diameters coincide in the area of ​​the slot 3, as can be seen particularly in the sectional view and in the elevation according to [reference]. Figure 3This is clearly visible. A transition area, designated 6, extends between the two strain relief sections 51 and 52. In the embodiment shown here, this transition area is formed by a curve that transitions continuously and smoothly into strain relief section 51 and is connected to strain relief section 52 by an edge. Due to the design with the outer circumferences of strain relief sections 51 and 52 touching the opening 2 along the line of the slot 3, this transition area 6 changes in the direction of the slot 3 and increasingly approximates the shape of a continuous straight transition between the two strain relief sections 51 and 52 found there.

[0033] The strain relief section 52, with the smallest cross-section of the through-opening 2, has a certain proportion of the axial length of the entire through-opening 2. This axial length of the entire through-opening 2 corresponds to the thickness of the strain relief sleeve 1 in the axial direction a, which is shown in the illustration of the Figure 4 The proportion of the axial length d of the strain relief section 52 with the smallest cross-section in relation to this total axial length, i.e., the thickness D of the strain relief sleeve 1, should be more than 10%, preferably more than 15%, and particularly preferably more than 20%. The ratio d / D is thus at least 0.1. In the illustration of the Figure 4This ratio is approximately 0.35, meaning that the strain relief section 52 with the smallest cross-section comprises about 35% of the total axial length D of the through-opening 2. This value must be adjusted accordingly depending on the Shore hardness of the material, which is preferably in the range of 30 to 90 Shore A. Ultimately, this value also depends on the two cross-sections of the strain relief sections 51 and 52. These can be, for example, 5 mm on one side and 7 mm on the other, as in the embodiment shown above, in order to securely, tightly, and with strain relief accommodate cables between 5 and 8 mm in diameter within the strain relief grommet 1.

[0034] This special design of the through-opening 2 of the strain relief grommet 1 now makes it possible to accommodate cables 20 with a diameter corresponding to the cross-section of the strain relief section 52 of the through-opening 2 just as securely, reliably, and tightly as cables 20 corresponding to the cross-section of the strain relief section 51 of the through-opening 2. With the thinner cable 20, the strain relief section 52 seals against the cable 20, ensuring a seal and, at the same time, reliable strain relief of the cable 20 due to its comparatively large contact area. In the strain relief section 51, the strain relief grommet 1 does not touch the cable 20.In practice, it is therefore advisable to install the strain relief grommet 1 with the cable 20 in such a way that the side of the strain relief grommet 1 to which the strain relief section 52 connects faces the area to be sealed, so that liquid cannot penetrate into the area of ​​the strain relief grommet 1 in the first place. When using a larger cable 20 up to the diameter of the strain relief section 51 of the through-opening 2, the opposite is true.

[0035] This is in both Figures 5 and 6 schematically represented. The structure is essentially that of Figure 4 In the presentation of the Figure 5A cable, for example with a diameter of 5 mm, is inserted. The strain relief section 52 seals this cable 20 from the environment as soon as the strain relief grommet 1 is crimped accordingly, and simultaneously ensures good strain relief. An annular gap, here designated 21, remains between the strain relief section 51 and the cable 20. In the illustration of the Figure 6 A larger cable, for example with a diameter of 7 mm, is inserted into the same strain relief grommet 1. The strain relief section 52 is deformed very strongly here, as shown in the illustration of the Figure 6This is indicated. This may also apply to the slot 3 in the axial area of ​​the strain relief section 52. This is indicated here by the correspondingly deformed surface contour of the strain relief grommet 1. Such a contour no longer ensures a reliable seal, although it can normally guarantee strain relief. Reliable sealing and strain relief are ensured here in the area of ​​the strain relief section 51, whose cross-section matches the diameter of the cable 20, thus achieving a tight seal. Ideally, the assembly is installed so that the sealed side faces outwards, for example when installed in a control cabinet, in order to reliably prevent the ingress of liquid between the cables 20 and the strain relief grommet 1.

[0036] The variant in Figure 7 shows another possible design. As in Figure 5As discussed, when a small-diameter cable 20 is inserted, an annular gap 21 forms around the cable 20 in the area of ​​the strain relief section 51 with the larger cross-section. To seal this annular gap 21, a sealing lip 22 can be provided, also with the small open cross-section or with an even smaller open cross-section than that of the strain relief section 52 with the smallest cross-section. This sealing lip 22 transmits in the Figure 7 In the illustrated embodiment, no forces are exerted. The strain relief and primary sealing are carried out analogously to the illustration in [reference to illustration]. Figure 5 between the strain relief section 52 and the cable 20. The sealing lip 22 serves only to seal the annular gap 21 in order to prevent the accumulation of coarse dirt and moisture in its area.

[0037] Alternatively, it would also be conceivable to provide a further strain relief section 53 with the required width of d > 0.1D instead of the sealing lip 22.

[0038] The Figures 8 to 14 show alternative embodiments of the inner contour of the through-opening 2. In the illustration of the Figure 8 A very simple variant with a step between the strain relief section 51 and the strain relief section 52 is shown. In the illustration of the Figure 9 A continuous transition between the train relief sections 51 and 52 is shown. In the illustration of the Figure 10 A stepped structure is again shown, in which three different strain relief sections 51, 52, 53 are arranged in descending order of their cross-sectional area. This enables the reliable accommodation of three different cable diameters. In the illustration of the Figure 11A similar structure with three strain relief sections 51, 52, 53 is shown, whereby the transitions here are again similar but fundamentally reversed as in the illustration of the Figure 4 are designed with a continuous transition to one strain relief section and an edge at the transition to the other strain relief section. Furthermore, a kind of introductory phase is shown between the first strain relief section 51 and the edge of the strain relief grommet 1. This allows for a reliable seal even with larger cable diameters. In the illustration of the Figure 12 A further representation in a tiered structure can be seen. Unlike the representation of the Figure 8 The structure is chosen such that the steps in the axial direction of the passage opening 2 are divided into two small strain relief sections 52, 53 and a correspondingly large or long strain relief section 51. Figure 13Figure 1 shows another variant with a side edge running diagonally to the central axis of the through-opening 2 on the side of the slot 3. Other shapes deviating from a linear profile are also conceivable, which serve in particular to simplify manufacturing by injection molding, for example a slight bend resulting from draft angles or similar features. Figure 14 Figure 3 shows a side view of a non-linear path in the axial direction a of slot 3. In addition to the wave-like path shown here, one or more steps or similar would also be conceivable.

[0039] Figure 15 Finally, Figure 1 shows a variant of the strain relief grommet 1 with a round outer contour that deviates from a rectangular or square one. The through-opening 2 is analogous to the illustration in Figure 2. Figure 3 The view is shown from the side of the strain relief section 51 with the larger cross-section. This is shown in Figure 15A variant with a cross-sectional contour of the strain relief section 51 that deviates from the round shape can be seen. The cross-sectional contour of the strain relief section 51 with the larger cross-section has, as an example, a bulge 18 on its side facing away from the slot 3. Other contours, such as oval, polygonal, or similar, are also conceivable. The other strain relief section 52 is shown here as an example with a round cross-sectional contour; however, a deviation from this would also be conceivable. Particularly in the area of ​​the strain relief section 51 with the larger cross-section, the deviating contour is helpful because it allows the material of the strain relief sleeve 1 to "flow" better around the larger cable and thus permits greater differences in cross-sections.

[0040] The Figure 16Figure 1 shows an alternative embodiment of a strain relief grommet 1 with four through-openings 2, essentially analogous to the illustration of the Figures 1 to 4 with an additional cut XIX - XIX of Figure 16 in the representation of Figure 19 Here, each of the two through-openings is analogous to the one in Figure 4 The depicted passage opening is formed. In principle, all variations of the inner contour, as shown in the Figures 7 to 13 and 15 are conceivable. As an alternative to the embodiment shown here, in which each of the through-openings 2 has its own slot 3 to an outer surface 4 of the strain relief grommet 1, a design would also be conceivable in which, for example, the two right-hand through-openings 2 in the illustration of the Figure 13 via a slot with the two left through-openings 2 in the illustration of the Figure 16 would be connected and then extend outwards via slot 3.

[0041] In the presentation of the Figure 21 Another alternative strain relief grommet 1 can be seen. The section according to line IV-IV in the illustration of the Figure 21 In his view, this corresponds to the cut according to Figure 4 . Here too, the design can be analogous to the explanations in the Figures 7 to 13 and 15 This will be done accordingly.

[0042] In the Figure 22 in a front view and in the Figure 23 A cable gland 7 can be seen in a top view. In the exemplary embodiment, it consists of the Figure 22 The frame consists of a lower frame 8 and a largely identical frame cover 9, each U-shaped. Intermediate webs 14 create individual chambers 15 in the frame 8 and also in the frame cover 9. The strain relief grommets 1 with the cables 20 (not shown) are arranged in these chambers 15.

[0043] Depending on requirements, different strain relief grommets 1, e.g., in the versions described above, can be inserted into the chambers 15, which have a width corresponding to one of the strain relief grommets 1 and a height that can accommodate, for example, two strain relief grommets 1 each. When assembled, the cable gland 7 is designed for screwing to the wall of a control cabinet (not shown) via holes 13 in the side panels of the frame 8 and / or the frame cover 9. In the illustration of the Figure 22 This includes ten individual strain relief grommets 1, each with a through-opening 2, in a view analogous to that shown in Figure 3 inserted into the cable gland 7. The frame 8 and the frame cover 9 of the cable gland 7 are, as shown in the illustration of the Figure 22As can be seen, they are screwed together via three screws 10 to apply the necessary pressure for sealing and strain relief to the strain relief grommets 1 and the cables 20 located in the through-openings 2, which are not shown here.

[0044] In the Figure 24 An alternative embodiment of such a cable gland 7 is shown. In the three-dimensional view, only two of the strain relief grommets 1 are shown in an embodiment analogous to the illustration in the Figures 16 to 20 They are shown accordingly. They are arranged in one of the chambers 15; the remaining chambers 15 are left empty here for improved visibility.

[0045] The cable gland 7 also consists of a frame 8 and a frame cover 9 – which is flat in this variant. The frame 8 is essentially U-shaped and has five individual chambers 15, which are in turn separated from each other by the intermediate webs 14, and which have a grid dimension in their width corresponding to one of the strain relief grommets 1, comparable to the frame in the illustration of the Figure 22 Since only one of the chambers 15 contains two of the strain relief grommets 1 with their cables 20 stacked on top of each other, the chambers 15 are here in comparison to the illustration in Figure 22 Very easy to see. In the front view of the Figure 25 The same structure is shown in the open state. The frame cover 9 has two locking hooks 16 which laterally engage the actual frame 8, as is also shown in the three-dimensional view of the Figure 24This can be seen. After inserting the strain relief grommets 1, whereby in practice all chambers 15 of the frame 8 are filled with the strain relief grommets 1 or corresponding blanking plugs for sealing, the frame cover 9 only needs to be pressed on by hand so that the frame cover 9 snaps into place. This is shown in the sectional view of the closed cable gland 7 in the Figure 26The locking hooks 16 of the frame cover 9 are seated in corresponding recesses 11 and are locked into place. To stabilize the width of the frame 8 after the frame cover 9 is fitted, several interlocking elements 12 are also provided. This ensures that the width of the frame 8 after the frame cover 9 is installed always corresponds to the desired width, and that the individual chambers 15 within the frame 8 and between the intermediate webs 14 are reliably maintained at the specified width. This is particularly important because the strain relief grommets 1 are crimped onto the frame cover 9. Different widths of the individual chambers 15 due to deformation would lead to different pressures on the strain relief grommets 1, thus impairing the seal.To prevent this, for example, conical pins and corresponding conical bores in the counterpart can be provided as corresponding positive-locking elements 12. This ensures that the width of the individual chambers 15 separated by the intermediate webs 14 on the one hand, and of the frame 8 as a whole on the other, remains constant, so that a uniform pressure can be exerted by the frame cover 9 on the strain relief grommets 1 located in the respective chambers 15, in order to seal them uniformly across the entire assembly.

[0046] Regardless, different grid dimensions of the chambers 15 in width within a frame 8 with the respective matching strain relief grommets 1 are of course conceivable.

[0047] In the presentation of the Figure 27This is another variant of the cable gland 7 with the frame 8 and the frame cover 9, shown here to accommodate only one of the chambers 15 and one of the strain relief grommets 1. The frame 8 and the frame cover 9 are again very similar in design and each enclose the strain relief grommet 1 along a section of its outer surface, shown here purely as an example, each by half. They are locked together by two locking hooks 16, although a screwed connection would also be conceivable. The assembled combination of frame 8 and frame cover 9 with the strain relief grommet 1 and the inserted cable 20, which is not shown here, is then passed through an opening, e.g., in a control cabinet, and screwed together using a nut and thread 17 (not shown here).

[0048] The Figure 28Figure 1 shows a cable gland 7 in which the frame 8 is a single piece and not open on one side. The chambers 15 are again formed by a cross-shaped intermediate web 14. The cables 20 (not shown) can thus be guided through the frame 8. The intermediate web 14 is then inserted and / or the strain relief grommets 1 are placed around the cables 20. These are then inserted into the frame 8 in the axial direction a, possibly all together with the intermediate web 14, and held in place by friction and / or positive locking.

[0049] All variants from the different embodiments can, of course, be combined with each other as desired. For example, the cable gland 7 can also be used with a round chamber 15, or a cable gland analogous to the one shown. Figure 27with a one-piece frame, etc. The deviation in the shape of the through-opening 2 for rectangular or square strain relief grommets 1 can also be accommodated with all variants according to the Figures 4 to 21 They can be combined accordingly, and these variants can also be combined with each other, and so on.

Claims

1. A strain relief grommet (1) made of an elastic material with at least one axial through-opening (2) for receiving at least one cable (20) 1.1 in the axial through-opening (2), which 1.2 is foldably connected to an adjacent through-opening (2) or an outer side (4) of the strain relief grommet (1) via a slot (3), wherein 1.3 each of the through-openings (2) has at least two strain relief sections (51, 52, 53) of different cross-section one behind the other in the axial direction (a), wherein 1.4 the at least two strain relief sections (51, 52, 53) of different cross-section are arranged eccentrically to one another, wherein 1.5 the strain relief section (52) with the smallest cross-section of the through-opening (2) constitutes at least 10%, preferably at least 15%, of the axial length (D) of the respective through-opening (2), wherein a transition region (6), which connects the adjacent strain relief sections (51, 52, 53), is arranged between each of the at least two strain relief sections (51, 52, 53) of different cross-section, wherein, 1.6 on the side of the slot (3), the outer circumferences of the at least two strain relief sections (51, 52, 53) of different cross-section directly adjoin one another, so that the outer circumferences of the strain relief sections (51, 52, 53) in line with the slot (3) contact one another, characterised in that the transition region (6) changes in the direction of the slot (3) and increasingly approaches the corresponding shape of a continuous straight transition between the strain relief sections (51, 52, 53).

2. The strain relief grommet (1) according to claim 1, characterised in that the transition region (6) is formed in the shape of a step or a slope on the side facing away from the slot (3), as seen in a cross section through the through-opening (2).

3. The strain relief grommet (1) according to claim 1, characterised in that the transition region (6) is formed as a continuous transition on the side facing away from the slot (3), as seen in a section transversely through the through-opening (2).

4. The strain relief grommet (1) according to claim 1, characterised in that the transition region (6) is formed via a curve on the side facing away from the slot (3), as seen in a section transversely through the through-opening (2), which curve transitions continuously into the one strain relief section (51, 52, 53) and over an edge into the other strain relief section (53, 52, 51).

5. The strain relief grommet (1) according to any one of claims 1 to 4, characterised in that each of the through-openings (2) has at least three strain relief sections (51, 52, 53) of different cross-sections, which follow one another in the axial direction (a), in particular sorted according to the size of the cross-sections.

6. The strain relief grommet (1) according to any one of claims 1 to 5, characterised in that the elastic material has a Shore hardness of less than 100 Shore A, preferably a Shore hardness of 30 to 90 Shore A.

7. The strain relief grommet (1) according to any one of claims 1 to 6, characterised in that at least one of the through-openings (2) has a sealing lip (22) in the region of at least one of the strain relief sections (51, 53) with one of the greater cross-sections.

8. The strain relief grommet (1) according to any one of claims 1 to 7, having exactly one through-opening (2), characterised in that the central axis of the strain relief section (52) with the smallest cross section is arranged centrally in the surface of the strain relief grommet (1) which is perpendicular to the axial direction (a).

9. A cable bushing (7), having strain relief grommets (1) according to any one of claims 1 to 8, having a frame (8) which is formed with one or more chambers (15) separated by intermediate webs (14), wherein the chambers (15) are adapted to each receive at least one strain relief grommet (1).

10. The cable bushing (7) according to claim 9, characterised in that the frame (8) is adapted to be open on one side and substantially U-shaped, and having a frame cover (9) for closing the U-shaped frame, wherein, in the assembled state, the at least one strain relief grommet (1) is braced in the at least one chamber (15) by the frame cover (9).

11. The cable bushing (7) according to claim 10, characterised in that, in the assembled state, the slots (3) of the strain relief grommets (1) extend in parallel to the greatest dimension of the frame cover (9).

12. The cable bushing (7) according to claim 10 or 11, characterised in that, in the assembled state, the frame cover (9) is latched to the frame (8) via latching elements (16, 11).

13. The cable bushing (7) according to claim 10, 11 or 12, characterised in that the frame cover (9) and the frame (8) have corresponding form-fitting elements (12), which ensure the desired width of the frame (8) and / or of the at least one chamber (15) when the frame cover (9) and the frame (8) are connected.