Cable routing

Abstract

Cable guide, comprising a central element (2) and a plurality of holding elements (23, 24) which are arranged one above the other in tiers, wherein the holding elements (23, 24) are connected in one piece to the central element (2) over a plurality of tiers (3, 4), characterized in that two holding elements (23, 24) arranged opposite one another are formed on one tier (3, 4), wherein the holding elements (23, 24) of two successive tiers (3, 4) are offset from one another so that a cable duct is formed on each of the two sides of the central element (2), or the holding elements (23, 24) are provided on four sides of the central element (2).

Description

Cable routing

[0001] The present invention relates to a cable guide comprising a central element and a plurality of holding elements which are arranged one above the other in tiers.

[0002] Today, office furniture such as desks typically contain a multitude of different devices, such as computers, telephones, and the like, which are usually arranged in such a way that the electrical cables for these devices have to be routed and laid over long distances to the connection points. This often leads to entire "cable spaghettis" in the work area, which can not only be visually unpleasant, but also pose an accident risk, particularly if the cables accumulate on the floor. In addition, the cables are often laid in a confusing manner, making it difficult to easily identify the individual cables and the relevant devices. To prevent these cables from hanging loosely on the desk or simply being attached under the tabletop, it is advisable to gather the cables together and arrange them in a cable bundle.

[0003] Various solutions have been established for bundling cables, ranging from the use of cable ties or hose clamps to the use of cable conduits or cable guides. For example, DE 4428680 C1 describes a flexible link chain for guiding cables, lines, and hoses, consisting of several flexibly connected chain links.

[0004] EP 1394915 A1 describes a cable guide for connecting cables of electrical devices leading from a workstation to corresponding connection points. The guide elements consist of a series of interconnectable guide elements that have chambers or openings for inserting cables. The individual guide elements are arranged on a continuously flexible element, with the free ends of the flexible element being connectable to a fastening part.

[0005] US Pat. No. 5,900,586 A discloses a flexible cable carrier consisting of a plurality of spaced-apart and sequentially connected guide elements and a continuous central flexible tube. Each guide element is supported by the tube and is provided with slotted outer cavities for accommodating the cables.

[0006] Furthermore, DE 101 25 175 A1 discloses a movable guide for a flexible cable harness in a vehicle, in particular between the vehicle floor and a vehicle seat. FR 26 72 442 A1 relates to a deformable duct for guiding electrical conductors. This duct comprises a rib that forms a stiffener and extends longitudinally, said rib carrying a series of stepped lateral feet. GB 22 33 163 A shows a cable guide for use with office furniture, comprising upper and lower end elements and a flexible guide formed from elements with C-shaped parallel ribs and T-shaped elements. Finally, EP 1 193 819 A2 relates to a modular cable duct guide for laying electrical cables, comprising a plurality of modular elements that can be interconnected via locking elements.

[0007] The well-known cable guides allow cables to be routed precisely into cavities and installed there in a protected manner, while simultaneously creating a visually appealing appearance in the work area. However, the cables usually have to be inserted into the guide elements through narrow slots, and handling becomes significantly more difficult with the number of cables. Re-routing or re-routing cables is therefore time-consuming and difficult.

[0008] The object of the present invention is to provide a cable guide which is easy to handle, inexpensive to manufacture and at the same time has an aesthetic overall appearance.

[0009] This object is achieved by a cable guide according to claim 1, comprising a central element and a plurality of holding elements which are arranged one above the other in tiers, in that the holding elements are connected in one piece to the central element over several tiers.

[0010] The present invention thus provides, for the first time, a one-piece cable guide with a specially structured design and easy cable routing. A corresponding cable chain can be manufactured in a single operation, significantly reducing manufacturing costs and the time required for production. Furthermore, assembly effort can be significantly reduced, thus also saving costs.

[0011] According to the invention, the holding elements are offset from each other in tiers. This allows for very simple cable routing without the need for complex assembly. At the same time, sufficient spacing is ensured, which not only ensures the secure holding of the cables but also allows for convenient cable insertion.

[0012] In addition, two opposing support elements are provided on one level. These opposing support elements make it possible, for example, to route two cables completely separately, making re-routing or re-routing cables much easier.

[0013] A preferred embodiment may provide for each retaining element to be U-shaped. A U-shaped retaining element has proven sufficient for guiding the cable.

[0014] The support elements arranged opposite each other on a single level can share a common central U-shaped leg. This simplifies the shape and requires only a minimum of necessary walls.

[0015] Furthermore, a base element of one of the holding elements can extend from both ends of the common middle U-leg.

[0016] Each of the retaining elements is designed in the form of a chamber that is open along one side wall, thus ensuring easy access. The cable therefore does not have to be inserted or forced into a narrow gap, but can simply be inserted into the chamber formed by three walls.

[0017] The design of the holding elements as U-shaped elements is a particularly preferred embodiment. However, the holding elements can also have a shape derived from the U-shape or a completely different shape. For example, the open side of the U-shaped chambers can be partially closed. Furthermore, the two holding elements arranged on a holding element level could also be Z-shaped, M-shaped, etc., when viewed from above.

[0018] It has proven effective to arrange the base elements of two retaining elements arranged one above or one below the other, opposite each other. The offset base elements ensure sufficient cable retention in the individual open chambers, preventing the cable from "breaking free" from the chambers. The offset chambers create a semi-open cable duct that adequately secures the cable along all four side walls of the chamber.

[0019] According to another preferred embodiment, the central element can be designed with an upper and / or lower connection. This provides a very simple fastening option, both on the piece of furniture and in the area of ​​the floor. Since these connections are generally integrally connected to the central element, additional time-consuming assembly steps for completing the cable guide are eliminated, and the cable guide can be connected directly to the piece of furniture.

[0020] It has proven preferable for the end piece to be designed as a stand element in the form of two opposing support elements. In this case, the shape of the cable routing is also reflected in the base, creating a visually cohesive interior. At the same time, it is possible to influence the size and weight to ensure secure stability. The shape of the two opposing support elements provides sufficient standing space without appearing too bulky.

[0021] According to another preferred embodiment, the central element can be designed with a varying cross-section or diameter. By influencing the cross-section or diameter, the strength of the central element can also be influenced, allowing the formation of regions with varying degrees of flexibility. This makes it possible to provide a cable guide in which rigid and flexible regions alternate in a targeted manner, providing sufficient flexibility despite the one-piece design. The rigid and flexible regions can also be designed to seamlessly merge into one another.

[0022] Another preferred embodiment can provide that the central element has a predetermined length and a plurality of central element sections, wherein the individual central element sections can be connected to one another and the individual central element sections have the same or different cross-sections. This embodiment is based on a modular system, wherein predetermined sections, in particular sections of 10 cm, 25 cm, 50 cm, 75 cm and / or 100 cm, of the cable guide are provided. Each section comprises a central element section and a plurality of levels of holding elements connected to it. In this way, the assembly of a corresponding cable guide is considerably simplified since only a few elements have to be connected to one another. At the same time, a decision can be made on site, i.e. during assembly, as to whether and in which position a rigid or flexible element is advantageous.

[0023] The individual central element sections can be connected via a positive or non-positive connection. This allows the cable guide to be installed quickly and easily, without the need for special or additional tools.

[0024] It has proven particularly preferable for the central element and / or the holding elements to have flexible and rigid sections, with rigid sections preferably adjacent to the upper and / or lower connection. Corresponding rigid and flexible sections, as well as the different diameters, make it possible to provide a movable cable guide in positions where this flexibility is actually necessary. This ensures very high flexibility of the cable guide without additional manufacturing effort. If the holding elements are designed to be flexible at least in sections, they can, for example, yield laterally and thus hold a cable guided in a slalom-like manner on both sides.

[0025] The cable guide according to the invention is particularly preferably manufactured by injection molding. This process has proven particularly suitable in practice for producing corresponding cable guides cost-effectively.

[0026] In the following, exemplary embodiments of cable guides according to the invention are explained in more detail with reference to a figure, although the invention is not limited by these figures. It shows: Fig. 1 a three-dimensional representation of a cable guide element according to a first embodiment; Fig. 2 a three-dimensional representation of a cable guide element with an upper connection according to a second embodiment; Fig. 3 a three-dimensional representation of a cable guide element with floor connection according to a third embodiment; Fig. 4 a three-dimensional representation of a cable guide element according to a fourth embodiment; and Fig. 5 a three-dimensional representation of a cable guide element according to a fifth embodiment

[0027] In Fig. 1 shows a cable guide section 1 in three-dimensional view, comprising a central element 2 and two holding element levels 3, 4 arranged on the central element 1 at a predetermined distance from one another. The illustrated embodiment is only a section of a cable guide according to the invention; in actual use, a corresponding cable guide section would be repeated any number of times one above the other in order to provide the complete cable guide.

[0028] As shown, the central element 2 is designed as an elongated element with a predetermined height, comprising two long sides 5, 6 and two transverse sides 7, 8. Each holding element level 3, 4 is arranged in the region of the long sides 5, 6 and arranged essentially parallel to these. In detail, each holding element level 3, 4 has two U-shaped holding elements 23, 24 which share a common central U-leg 9, wherein the base elements 12, 13 of the two U-shaped holding elements 23, 24 are arranged at opposite ends of the common U-leg 9 and extend away from there in opposite directions. The respective outer U-legs 14, 15 have the same length as the U-leg 9 in this example.

[0029] The outer U-legs 14, 15 and the base element 12, 13 can have the same thickness or can be designed with different thicknesses depending on the desired elasticity of the holding element. Preferably, the common U-leg 9 is thicker than one of the U-legs 14, 15.

[0030] Each holding element 23, 24 of this embodiment is thus designed in the form of a laterally open chamber, if the base element 12, 13 is considered a side wall, and the two U-shaped legs 14, 15 are considered the front and rear sides. The holding elements 23, 24 located adjacent to one another in a tier 3, 4 are each open in opposite directions. Depending on the arrangement of the base elements 12, 13, the holding element tiers 3, 4 can therefore have the shape of an S or a 5, or the shape of a 2 when viewed from above.

[0031] The individual holding element levels 3, 4 are arranged on the central element 2 in such a way that the central element 2 is integrated into the common U-leg 9. Depending on the design, the U-leg 9 can have the same width as the central element 2. In this case, the long sides 10, 11 of the U-leg 9 run in a parallel plane with the long sides 5, 6 of the central element 2. Likewise, it is also possible for the U-leg 9 to be narrower or wider than the central element 2. With a wider U-leg 9, a stepped appearance is achieved, with the long sides 5, 6 of the central element 2 each interrupted by the protruding U-legs 9. Fig. 1 shows an example of a corresponding step-shaped optic.

[0032] By forming the wider U-leg 9, greater stability is achieved in this area, thereby ensuring that movement in the area of ​​the central element 2 only takes place between the holding element levels 3, 4, ie in the area of ​​the central element 2 with a narrower cross-section, but not in the area of ​​the holding element levels 3, 4.

[0033] Regardless of the width, the U-leg 9 in the present embodiment preferably extends beyond the central element 2 on both sides, ie the long sides 10, 11 of the U-shaped element 9 are longer than the long sides 5, 6 of the central element 2. Likewise, the holding element levels 3, 4 could also extend only over the area of ​​the central element 2.

[0034] As further stated Fig. 1, the two consecutive holding element levels 3, 4 are offset from one another, i.e., they alternately have the shape of an S or a 5 and the shape of a 2, so that the base elements 12, 13 of the holding elements 23, 24 arranged one above the other are arranged alternately at the front or rear end of the common U-leg 9. The U-shaped holding elements 23, 24 of the holding element levels 3, 4 arranged one above the other form a cable duct on either side of the central element 2. Each cable duct is formed by the inner sides of the U-shaped holding elements 23, 24, so that an openwork structure is achieved.

[0035] In order to insert a cable into a correspondingly designed cable guide 1, it is necessary to insert the cable in a slalom-like manner into the individual U-shaped holding elements 23, 24, whereby the cable is inserted from the open side into a U-shaped holding element 23, 24 of a holding element level 3, 4 and is guided between the top and bottom of the stacked long sides 14, 15 to the open side of the next U-shaped holding element 23, 24 located above or below it. The very open and perforated structure of the cable guide 1 makes it possible to insert individual cables quickly and efficiently and to remove them equally quickly from the cable guide 1.

[0036] The entire cable guide 1, i.e., the central element 2 as well as the various holding elements 23, 24, are manufactured in one piece, for example, by an injection molding process. This makes it possible to firmly connect the central element 1 and the holding elements 23, 24 and to produce them in a single operation using simply constructed injection molding tools. The cable guide 1 can extend in one piece over the entire length, for example, between the floor and underside of a desk or piece of furniture, or from a ceiling to a piece of furniture or the floor, or it can consist of individual cable guide elements that can be connected to one another as desired.In this context, for example, cable management elements with a length of 10 cm, 25 cm, 50 cm, 75 cm and 100 cm, especially 25 cm, have proven to be particularly suitable, since such elements are particularly cost-effective in storage, as well as in transport, packaging and handling.

[0037] At the Fig. 1, the central element 2 has the same cross-section over its entire length, in particular the same length and width. By changing these dimensions, it is possible to change the mobility of the cable guide 1 as a whole, i.e. the cable guide 1 can be designed with rigid and differently flexible areas. To achieve this, for example, the cross-section of the central element can be suitably changed. In this way, it is possible to combine rigid and flexible areas in a targeted manner, for example to design the cable guide rigidly near the floor so that it extends vertically upwards and does not lie on the floor, and to design it more flexibly in a connecting area so that the cable guide can be angled in a targeted manner and guided to certain areas, even if these cannot be reached via a direct straight path.

[0038] The cross-section of the central element 2 can be modified as desired. It is possible to design the central element 2 with a square cross-section, in which the long sides have the same width as the short sides, or to simply change the dimensions while maintaining the original cross-sectional ratio. Since the retaining elements 23, 24 are not affected or influenced by the reduction in the diameter of the central element, the cable guide as a whole remains sufficiently rigid and self-supporting.

[0039] Furthermore, by changing the cross-section, not only the flexibility or rigidity of the cable guide can be influenced, but also the desired direction of flexibility or rigidity, so that, for example, the cable guide only bends in one desired direction. A corresponding design has proven particularly useful for height-adjustable desks where a deliberate preferred direction of cable routing is desired. This means that when the desk is retracted, the cable guide always curls into an "S-shape" or "U-shape," with the bending ranges and direction being predetermined.

[0040] Fig. 2 shows a cable guide 1, which corresponds to Fig. 1, wherein an upper portion of the cable guide 1 is shown, comprising a connector 16 for attachment to a piece of furniture, in particular a desk. In contrast to the Fig. 1, in the embodiment shown here, the U-leg 9 has the same width as the transverse sides 7, 8 of the central element 2, so that the two longitudinal sides 10, 11 of the U-leg correspond to the longitudinal sides 5, 6 of the central element 2 and the central element 2 is designed without projections, ie smooth, in the area of ​​the longitudinal sides.

[0041] At the upper end edge of the central element 2, this merges into a connection 16, which, like the holding elements 23, 24, is formed integrally with the central element 2. The connection 16 is in the form of an elongated element and is arranged with one long side on the upper cross-sectional surface of the central element 2. The central element 2 is positioned approximately centrally in the area of ​​the connection 16. The connection 16 has a length that extends on both sides beyond the central element as well as beyond the holding elements 23, 24. At both ends, elongated holes 17, 18 are open to a side edge, by means of which the cable guide 1 can be attached to a piece of furniture, for example by screwing.In addition, receiving openings 19, 20 can be formed on both sides next to the elongated holes 17, 18, into which, for example, magnets can be inserted in order to provide an additional or different fastening option.

[0042] Fig. Figure 3 shows a further cable guide 1, wherein a lower part of the cable guide is shown along with a floor connection 21. The floor connection 21 is attached to the central element 2 in the same way as the one shown in Fig. 2, i.e. the central element 2 is positioned in the area of ​​an elongated element. In this case, the elongated element in the area of ​​the floor connection 21 is, however, only a partial element of the overall shape. The floor connection has the same shape as the two holding elements 23, 24 of a level, i.e. it is designed in the shape of a 5 or a 2. In accordance with the alternating design of the individual holding element levels 3, 4, the floor connection is also offset from the last level, so that the base elements of the U-shaped holding elements 23, 24 of the last level and the floor connection are opposite one another. Like the upper connection 16, the floor connection 21 is also designed in one piece with the central element 1. The floor connection can be designed to be sufficiently strong by suitable selection of the dimensions, i.e. the longer the cable guide, the more stable orThe floor connection should be heavier.

[0043] Although the cable guide can be manufactured as a single element, it has proven particularly effective in practice to design the cable guide in the form of individual elements, for example, comprising approximately 25 cm long cable guide sections. End sections with connectors can also be manufactured. This makes it possible to provide different cable guide elements with differently designed connectors, allowing customers to choose between different connector variants, which can then be attached to the cable guide without complex assembly. Since only short sections are manufactured along with the respective connector, storage costs, packaging costs, packaging size, and transport costs can be kept low.

[0044] In contrast to the Fig. 1 and Fig. 2, the cable guide according to the third embodiment has a central element 2 which was manufactured with differently flexible areas, i.e. the cross-section of the central element 1 changes. Directly at the floor connection or the floor plate 21 there is firstly arranged a cable guide element, comprising a total of eight holding element levels 3, 4, with a wide central element 2, whereby the cable guide 1 is rigid in the area of ​​the floor connection 21 and the cable guide 1 extends essentially vertically upwards. This is followed by a section of the cable guide which is distinguished by a central element 22 with a reduced cross-section. It is clear that the dimensions of the central element 22 have been reduced both with regard to the transverse side and the longitudinal side.Due to the central element 22 with this significantly reduced cross-section, the corresponding area of ​​the cable guide 1 has considerably more flexibility, so that it is possible to bend the cable guide in a desired direction.

[0045] Although two clearly defined areas, each with the same cross-section of the central element 2, 22, are shown here, the cable guide can also be designed with a gradually changing cross-section over its entire length, whereby the cross-section can also change several times to influence the flexibility of the cable guide in individual sections. Particularly if the cable guide consists of individual cable guide sections, sections with different cross-sections can be provided in the form of a modular system, suitably selected, and attached to one another as desired.

[0046] Another embodiment of the cable guide according to the invention is shown in Fig. 4. In this embodiment, the central element 2 is essentially square. In each level 3, 4, two holding elements 23, 24 are arranged, which are positioned opposite one another. The individual holding elements 23, 24 are "mushroom-shaped", comprising a head region 25 and a stem region 26, via which the holding elements 23, 24 are attached to the central element 2. The stem region 26 is formed with a rectangular cross-section, wherein the cross-section in the present embodiment is larger than the cross-section of the central element 2. As a result, the holding element 23, 24 as a whole is formed to be less mobile than the central element 2, so that the holding elements 23, 24 can be pushed away sideways with increased force when a cable is inserted.The head region 25 is designed in the form of a square plate with rounded corners, wherein the stem region 26 is positioned centrally on the side of the head region 25 facing the central element 2.

[0047] Although in the illustrated embodiment the stem regions 26 are arranged centrally on the head regions 25, it is equally possible to arrange the stem regions 26 off-center of the head region 25.

[0048] Like the previously described cable guides, this cable guide 1 is also manufactured in one piece. Due to the square diameter of the central element 2, the cable guide according to Fig. 4 is a highly flexible cable guide that can be equally flexibly deflected in two axes, allowing for uncomplicated, simple, and quick cable installation. The cable 30 can simply be guided under the head regions 25 into an undercut provided below. Furthermore, preferably thin cables can also be guided and pressed in a slalom-like manner around the head regions 25 and stem regions 26 of the adjacent retaining elements 23, 24.

[0049] Since the support elements 23, 24 are provided on all four sides of the central element 2, four cables, for example, could be routed separately, each of which is easily accessible without interfering with the other cables. By offsetting the support elements 23, 24 on each level, a sufficiently large distance is created between the support elements 23, 24 arranged below or above one another on each side, significantly simplifying the routing of the cable.

[0050] The clear distance between two superimposed trunk sections 26 preferably corresponds to the diameter of the thickest cable to be threaded, whereby the standard dimensions of corresponding cables are used as a basis. If the trunk sections 26 are arranged in the center of the head section 25, a relatively straight alignment of a cable can be achieved by guiding it between the holding elements of two adjacent sides of the central element 2, i.e. assuming a corner position in a top view. Likewise, however, the cable can also be inserted in a slalom manner by wrapping it around the trunk sections 26 arranged directly above and below one another. If thicker cables are threaded, the individual holding elements 23, 24 can be pushed to the side by the cables and thus held in place.

[0051] If tensile forces are exerted on the cable, especially during slalom-like cable laying, friction creates strain relief. If the cable is routed in a slalom-like fashion around as many trunk sections as possible, the tensile force brake can be increased. The cable is thus secured without additional components such as additional strain reliefs.

[0052] A similar embodiment as the embodiment according to Fig. 4 is also in Fig. 5. In contrast to the previous embodiment, here both the central element 2 and the stem regions 26 are designed with a round diameter. Likewise, the head region 25 is also designed with a round outer circumference. These round elements achieve a cable guide with high flexibility. When the cable is laid, the elements do not remain rigidly in their position, but are moved from their basic position by the cable, so that the cable is guided straight between the holders shifted to the right and left. The diameter of the head regions 25 is sufficient to ensure secure positioning of the cables, while at the same time maintaining a very delicate overall appearance.

[0053] In this embodiment, too, the clear distance between the trunk areas 26 corresponds approximately to the diameter of the thickest cable to be inserted. Fig. As can be seen from Figure 5, the stem region 26 is not formed with the same diameter over its entire length, but in the illustrated embodiment is conical, with a continuously changing diameter that is smallest in a central region. This shape of the stem region allows the cables to be centered and held particularly well.

[0054] Furthermore, the outer surface of the head regions 25 facing away from the central element 2 is convex.

[0055] The embodiments according to the Fig. 4 and Fig. 5 can be provided with one-piece terminals, whereby, particularly with regard to the floor connection, sufficient weight should be ensured to fix the cable routing on the floor.

[0056] Although only a connection element for a piece of furniture and a floor connection were described in the previously described embodiments, corresponding connections can also be designed as a connecting element for connecting two cable chains or for connecting to a housing. As a general rule, it has proven advantageous for the central element 2 to be designed with the desired flexibility in the area of ​​the connection in order to ensure a visually appealing transition from the connection.

[0057] If the cable guide is not provided as a long single element, but in the form of several short cable guide sections, the individual sections can preferably be connected to one another by simple connecting elements, for example locking elements or clip elements, which enable the individual sections to be connected quickly and easily.

[0058] The cable guides according to the invention can be manufactured from suitable plastic materials, which can be selected as needed according to the desired flexibility. The cable guides are preferably manufactured by injection molding.

[0059] Since the cable guides according to the invention are formed in one piece, the overall manufacturing effort is reduced considerably, since no subsequent manufacturing steps are necessary, for example, joining individual components.

Claims

[1] Cable guide, comprising a central element (2) and a plurality of holding elements (23, 24) which are arranged one above the other in tiers, wherein the holding elements (23, 24) are connected in one piece to the central element (2) over several tiers (3, 4), characterized by that two holding elements (23, 24) arranged opposite one another are formed on one level (3, 4), wherein the holding elements (23, 24) of two successive levels (3, 4) are offset from one another so that a cable duct is formed on both sides of the central element (2), or the holding elements (23, 24) are provided on four sides of the central element (2). [2] Cable guide according to claim 1, characterized by that each holding element (23, 24) is U-shaped. [3] Cable guide according to claim 2, characterized by that the holding elements (23, 24) arranged opposite one another in a level (3, 4) have a common central U-leg (9). [4] Cable guide according to claim 3, characterized by that a base element (12, 13) of a holding element (23, 24) extends away from both ends of the common middle U-leg (9). [5] Cable guide according to claim 4, characterized by that the base elements (12, 13) of two holding elements (23, 24) arranged above or below one another are arranged opposite one another. [6] Cable guide according to at least one of claims 1-5, characterized by that the central element (2) is formed with an upper and / or lower connection (16, 21). [7] Cable guide according to at least one of claims 1-6, characterized by that one end piece is designed as a stand element. [8] Cable guide according to claim 7, characterized by that the stand element is designed in the form of two opposite holding elements (23, 24). [9] Cable guide according to at least one of claims 1-8, characterized bythat the central element (2) is designed with a changing cross-section. [10] Cable guide according to at least one of claims 1-9, characterized by that the central element (2) has a predetermined length and a plurality of central element sections, wherein the individual central element sections can be connected to one another and the individual central element sections have the same or different cross-sections. [11] Cable guide according to claim 10, characterized by that the individual central element sections can be connected via a positive or non-positive connection. [12] Cable guide according to at least one of claims 1-11, characterized by that the central element (2) and / or the holding elements (23, 24) have flexible and rigid sections, wherein preferably rigid sections of the central element (2) adjoin the upper and / or lower connection (16, 21).

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