plug-in coupling

Abstract

Plug-in coupling, comprising a tubular plug-in part (1) having a circumferential retaining rib (3), a socket-shaped coupling body (2) provided with at least one locking hook (4, 4') for positive locking with the retaining rib (3), and a sealing arrangement inserted into an annular space (11) between the plug-in part (1) and a housing (8) of the coupling body (2), wherein the at least one locking hook (4, 4') is arranged to be radially movable between a position establishing locking with the retaining rib (3) and a position releasing this locking, wherein the locking hook (4, 4') is arranged on a coupling element (22) that can be axially inserted into the housing (8) and axially fixed in an insertion position, wherein the annular space (11) is axially separated by an annular shoulder (23) formed by an axial end face of the coupling element (22) and a sealing arrangement in the aforementioned Insertion position of this axially spaced,a further annular shoulder (24) formed by a radial step of the housing (8), wherein the annular shoulders (23, 24) form axial working surfaces of the sealing arrangement, wherein the annular space (11) is otherwise radially defined by the cylindrical, mutually facing smooth, radially spaced surfaces of the housing (8) and the insertion part (1), wherein the at least one locking hook (4, 4') is in contact with a ring element (28) and is arranged along its circumference such that the engagement state of the at least one locking hook (4, 4') with the retaining rib (3) can be released by radial deformation of the ring element (28), wherein during a coupling state the retaining rib (3) including a retaining edge (10) of the at least one locking hook (4, 4') engaging behind it is visible in a recess (29), so that the intended locking of the at least one Locking hook (4,4') formed retaining edge (10) with the retaining rib (3) of the insertion part (1) is visible from the outside, characterized in that the coupling element (22) consists of a ring body (15) on which at least one locking hook (4, 4') is formed with an intermediate axially parallel web (26), that the ring body (15) is dimensioned with regard to centering the insertion part (1), that axially parallel tabs (17) extending in one direction away from the coupling body (2) and elastically deformable inwards are formed on the ring body (15), that the tabs (17) are carriers on the outside of locking cylinders (16) which are designed via radial bores (19, 19') for locking the coupling element (22) with the housing (8).

Description

[0001] The invention relates to a plug-in coupling according to the preamble of claim 1.

[0002] These types of quick-connect couplings are used, for example, in vehicle manufacturing for fuel lines. They serve to connect a tubular insert, equipped with a circumferential retaining rib, to a socket-like coupling body. The insert can be made of plastic or metal and can be the end of a line or the connection fitting on a housing. The coupling body is usually made of plastic and mounted on a line, but it can also be part of a housing.

[0003] Plug-in couplings of this type are characterized by a locking mechanism acting between the coupling body and the insertion part and are designed to provide a tight connection between the respective pipe elements to be coupled. They are known in numerous forms, with particular attention paid to functional reliability and ease of installation.

[0004] From DE 43 00 037 C1, a plug-in coupling of the type mentioned above is known, in which the locking mechanism between the coupling body and the plug-in part is represented by a component that is radially displaceable relative to the main axis and is designed to engage behind the retaining rib of the plug-in part. Comparable plug-in couplings are known from DE 197 22 842 A1, DE 10 2004 062 887 B3, EP 1 719 944 A2, US 2004 / 0 189 001 A1, and DE 10 2006 019 257 A1. A disadvantage of these plug-in couplings is that the correct locking of the plug-in part in the coupling body is not always clearly visible from the outside. The plug-in couplings must be installed in two directions, significantly increasing the effort required for automated assembly. The number of components required is also high.

[0005] Another plug-in coupling is known, for example, from DE 44 13 346 C1, the locking mechanism of which is represented by a sleeve axially inserted into the coupling body and axially displaceable within limits in the insertion position. The sleeve consists of a ring positioned in the socket base of the coupling body, from which four webs extend axially parallel in a uniform circumferential distribution and towards the open end of the coupling body, two of which project diametrically opposite locking hooks on the inside for interaction with the retaining rib of the plug-in part.All webs are provided radially on the outside with projections which are axially limited and movably received in recesses of the coupling body, so that the sleeve can be engaged and moved axially relative to the coupling body via two projections formed on the outside of the webs not provided with locking hooks and protruding from the coupling body, in order to release the coupling state of the plug-in part with the coupling body.

[0006] A disadvantage of this plug-in coupling is that proper locking is not visible from the outside. Furthermore, the sleeve forms a contact surface for the O-ring seal. Due to the necessary axial movement of the sleeve, the O-rings are pushed into an axial end position when the plug is inserted and into the opposite axial end position when the coupling is pressurized. Dirt can penetrate the front area, which the O-rings must traverse on their way in. The O-rings undergo this movement every time the coupling is disconnected and reconnected, creating the risk that the O-rings will twist during this movement and / or that dirt particles will become trapped in the sealing areas, thus compromising a reliable seal. This is particularly significant because this type of coupling is also used in fuel lines, among other applications.A leak test during the assembly of the clutch as a unit is not possible, as the O-rings only assume their effective position in the assembled state.

[0007] Finally, DE 37 27 858 A1 discloses another plug-in coupling, which consists of a socketed coupling body designed at one end for connection to a hose and a plug-in part designed at its opposite end for connection to a line. The end of the coupling body facing the plug-in part is characterized by an annular body on the inside of which block-like locking segments are formed, designed for positive engagement behind a circumferential retaining rib arranged on the plug-in part. The annular body is connected to the coupling body via two axially parallel, diametrically opposed webs, which is further characterized by an internally cylindrical receiving chamber that interacts with two sealing rings, each received in grooves of the plug-in part.The coupling can thus be released by an oval deformation of the ring body. This insert requires the use of a special insert, which also serves as the carrier for the sealing rings. A specific assembly sequence is therefore necessary. Although there are recesses between the aforementioned ribs, whether a correct engagement state exists between the retaining rib and the locking segments cannot be reliably determined by visual inspection alone.

[0008] From DE 695 20 156 T2, a plug-in coupling is known, which consists of a plug-in part, a socket-shaped coupling body, and a coupling element fixed in the coupling body. The coupling element has locking hooks that are designed and configured to engage with a circumferential retaining rib of the plug-in part. The coupling element is also fixed in the coupling body by means of a locking mechanism. This locking of the coupling element to the coupling body is achieved via two diametrically opposed locking receptacles formed radially on the outside of the coupling body. These receptacles are designed to interact with locking tabs that extend radially outward relative to the coupling element, parallel to it.

[0009] The object of the invention is to improve a plug-in coupling of the type described above, while maintaining its functionality and a simple design, with regard to its ease of assembly. This object is achieved in such a plug-in coupling by the features of the characterizing part of claim 1.

[0010] A coupling element is provided which can be inserted into the coupling body and fixed in its axial position. This element forms a first axial contact surface for a sealing arrangement via an annular shoulder. It also forms the carrier for the at least one locking hook, which is intended to interact with the retaining rib. Together with a further annular shoulder formed by the housing of the coupling body, and in conjunction with the radially spaced cylindrical surfaces of the insertion part and the housing of the coupling body facing each other, an annular space is formed in which the sealing arrangement is fixed axially immovably and held in a sealing position against the aforementioned surfaces by virtue of elastic deformation.The function and position of the sealing assembly, which can consist of at least one sealing ring, are therefore not affected by inserting the plug-in part into or removing it from the coupling body. The plug-in part can be of a conventional cylindrical shape and, apart from the retaining rib, completely smooth-walled. It is evident that the plug-in coupling is characterized by relatively few components.

[0011] In addition to its function as a carrier for the locking hook(s), the coupling element also provides a centering function for the insert via its ring body. This is crucial for a reliable and consistently high-quality seal.

[0012] The fastening status of the coupling element in the coupling body can be determined from the outside by mere visual inspection.

[0013] The locking hooks are attached to a ring element. This allows for simple ways of depicting the unlocking of the locking hook's engagement with the retaining rib, simply by radially deforming the ring element.

[0014] The features of claim 2 are directed towards measures which are intended, alternatively or simultaneously and in a complementary manner, for the particularly simple verification of a correct locking state of the plug-in part in the coupling body.

[0015] The features of claims 3 and 4 are directed towards the representation of the ring shoulder and a further embodiment of the housing.

[0016] The features of claim 5 are directed towards a constructive representation of the coupling element with regard to the visual recognizability of a correct engagement state between the coupling body and the plug-in part. Essential here is the provision of a lateral recess and the positioning of the retaining rib and the locking hooks, such that their engagement with the retaining rib within the recess is visually perceptible from the outside.

[0017] The invention will be explained in more detail below with reference to the accompanying drawings, which show preferred embodiments. The drawings show: Fig. 1 a partial exploded view of the plug-in coupling according to the invention; Fig. 2 a longitudinal section of the plug-in coupling according to Fig. 1 in the intervention state; Fig. 3. A perspective front view of the coupling body to illustrate a release mechanism; Fig. 4 an exploded view of the plug-in coupling according to Fig. 1; Fig. 5 a cross-sectional view of the plug-in coupling corresponding to a section plane V - V of the Fig. 6; Fig. 6 a side view of the plug-in coupling according to Fig. 1 in intervention state.

[0018] The in Fig. The plug-in coupling shown in Figure 1 consists of a tubular plug-in part 1, a socket-like coupling body 2, and a coupling element 22. In the illustrated representation, the plug-in part 1 is not yet inserted into the coupling body 2. A circumferential retaining rib 3 is visible on the plug-in part 1, and locking hooks 4, 4' are arranged as a pair on the coupling element 22, positioned diametrically opposite each other. Both the coupling body 2 and the plug-in part 1 are provided at their opposite ends with connections 12, 13, to which a pipe or hose can be pressed or welded. However, other embodiments are also possible; in particular, these connections 12, 13 can be integral parts of a housing or another component.

[0019] Apart from its dimensions, the insert part 1 is only adapted to the coupling body 2 by the retaining rib 3 and is otherwise smooth-walled on the outside.

[0020] Fig. Figure 2 shows the engaged state of the plug-in coupling. When the plug-in part 1 is inserted into the coupling body 2, its retaining rib 3 engages an insertion chamfer of the locking hooks 4, 4', causing these to deform elastically radially outwards. This increases the distance between the hooks, allowing the plug-in part 1 to be pushed further towards the engaged state. As soon as the retaining rib 3 is behind the respective retaining edges 10, 10' of the locking hooks 4, 4', these spring back elastically until they come into contact with the smooth outer surface of the plug-in part 1. This creates a positive connection in the axial direction between the plug-in part 1 and the coupling body 2.

[0021] The coupling body 2 is characterized by a tubular housing 8, the inner diameter of which is larger than the outer diameter of the plug-in part 1, so that an annular space 11 is formed between them, in which a first sealing ring 5, a support ring 6 and a second sealing ring 7 are received in axial succession. These rings lie axially against each other in the engaged state of the plug-in coupling, with a radially extending annular shoulder 24, which delimits the annular space 11 on the side of the housing 8 facing the connection 12, forming an axial contact surface for the sealing ring 7.

[0022] When the insert part 1 is inserted, its free end is guided by the sealing ring 5, the support ring 6, and the sealing ring 7 within the annular space 11 of the housing 8. The sealing rings 5 ​​and 7 are elastically deformed and are radially tensioned between the cylindrical inner and outer walls of the annular space 11, thus between the radially facing sides of the housing 8 and the insert part 1, in such a way that they seal the annular space 11 against the outer space of the coupling body 2. The support ring 6 separates the two sealing rings 5 ​​and 7 to provide separate sealing areas for each. Simultaneously, the insert part 1 is centered within the annular space 11 of the housing 8.

[0023] The sealing ring 7 and the support ring 6 are optional and can be used when very high tightness and redundancy are required. In principle, a single ring-shaped sealing element is sufficient at this point.

[0024] As can be seen from a synthesis of the Fig. 3 and Fig. As can be seen from Figure 4, the coupling element 22 consists of an annular body 15, one side of which, facing the connection 1 in the engagement position, forms an annular shoulder which provides an axial contact surface for the sealing ring 5. The assembly consisting of the sealing rings 5, 7 and the support ring 6 is thus axially clamped between the contact surfaces represented by the annular shoulders 23, 24 and is thus uniquely fixed in its position.

[0025] On the ring body 15, specifically on the side opposite the ring shoulder 23, two axially parallel, diametrically opposed cylindrical tabs 17 are formed, between which, leaving slots 25, two cylindrical, also diametrically opposed, webs 26 extend, with the aforementioned locking hooks 4, 4' formed radially on the inside of the free ends of these webs, which face the insertion part 1. The webs 26 are further characterized by a step 27 extending outwards from the radial level of the ring body 15.

[0026] The numbers 22', 22'', 22''', 22'''' denote elastically springy connecting elements that are integrally formed at the radially outer points of the free ends of the webs 26 and, together with lateral, opposing, identical, segment-like unlocking elements 14, 14', form a polygonal ring element 28. In the installed state of the coupling element 22, which will be explained below, the radially outer locking hooks 4, 4' also project partially into recesses 29 of the housing 8, which are formed in its end face 30 facing the coupling element 22.

[0027] One potentially advantageous unlocking mechanism is described in Fig. Figure 3 shows that, to unlock, forces are applied to the unlocking elements 14 and 14' in the direction of arrows F and F'. These forces act via the connecting elements 22', 22'', 22'''', 22'''' on the locking hooks 4, 4' such that these deform elastically outwards in the direction of arrows S due to the symmetry properties of the ring element 28. This movement releases the positive locking in the axial direction between the insert 1 and the coupling body 2. The insert 1 can now be pulled out of the coupling body 2.

[0028] Fig. Figure 4 shows all components of the plug-in coupling in an exploded view. With 16, 16' ( Fig. 5) are defined as detent cylinders which are formed on the outside of the tabs 17 in opposite positions, extending perpendicular to a longitudinal axis of the ring body 15.

[0029] To assemble the components of the plug-in coupling, the sealing ring 5 is first inserted into the housing 8, followed by the support ring 6, and finally the sealing ring 7. The coupling element 22 is inserted into the housing 8 last. Alternatively, all of these components can be placed on an assembly mandrel, which then inserts them together into the housing 8. It is essential that all of these components can be inserted into the housing 8 in a single axial movement.

[0030] During this insertion movement, the detent cylinders 16, 16' abut the inner wall of the housing 8. A chamfer 20 on their end face causes the tabs 17, 17' to deform elastically radially inwards, allowing the coupling element 22 to be inserted further into the housing 8. As they continue their movement, the detent cylinders 16, 16' come into a position congruent with radial bores 19, 19' in the housing 8. Due to the elastic preload of the tabs 17, 17', the detent cylinders 16, 16' are inserted into the bores 19, 19' and form a positive fit, thus axially securing the position of the coupling element 22 in the housing 8. Since the bores 19 are openly accessible from the outside of the housing 8, the engagement state of the detent cylinders 16, 16' and thus the correct fixation of the coupling element 22 within the coupling body 2 can be checked by mere external inspection.

[0031] In this secured position of the coupling element 22, its annular shoulder 23 forms an effective surface for the sealing ring 5. At the same time, the ring body 15 of the coupling element 22 centers the insert part 1 in the housing 8. Due to the axial and radial fixation of the coupling element 22 in the housing 8, effective surfaces are defined axially on both sides of the arrangement of rings 5, 6, 7, between which this arrangement is axially fixed.

[0032] The installation state of the coupling element 22, characterized by the locking of the two locking cylinders 16, 16' in the bores 19, is further characterized in that, in the engaged state of the plug-in coupling, the facing end faces 28' of the ring element 28 and 17' of the tabs 17 are held relative to each other at a distance 31. A retaining edge 10, which as a respective integral part of the locking hooks 4, 4' is directly intended to engage behind the retaining rib 3, is located axially at a point within the aforementioned distance 31.

[0033] Fig. Figure 6 shows a fully engaged plug-in coupling according to the invention. The properly engaged position of the retaining edge 10 behind the retaining rib 3 can be visually verified, since the axial position of the retaining edge is positioned within the recess 29 defined by the distance 31.

[0034] Furthermore, it can be seen that when the locking hook 4 is properly engaged, its radial outer edge is flush with a housing edge 21 of the housing 8. If the locking hook 4 is not properly engaged, the retaining edge 10 rests on the outer diameter of the retaining rib 3, causing the locking hook 4 to deform radially beyond the housing edge 21, a circumstance that is both visually apparent and palpable.

[0035] Thus, there are two independently acting mechanisms of a rest control.

Claims

[1] Plug-in coupling, comprising a tubular plug-in part (1) having a circumferential retaining rib (3), a socket-shaped coupling body (2) provided with at least one locking hook (4, 4') for positive locking with the retaining rib (3), and a sealing arrangement inserted into an annular space (11) between the plug-in part (1) and a housing (8) of the coupling body (2), wherein the at least one locking hook (4, 4') is arranged to be radially movable between a position establishing locking with the retaining rib (3) and a position releasing this locking, wherein the locking hook (4, 4') is arranged on a coupling element (22) that can be axially inserted into the housing (8) and axially fixed in an insertion position, wherein the annular space (11) is axially separated by an annular shoulder (23) formed by an axial end face of the coupling element (22) and a sealing arrangement in the the aforementioned insertion position from this axially spaced,a further annular shoulder (24) formed by a radial step of the housing (8), wherein the annular shoulders (23, 24) form axial working surfaces of the sealing arrangement, wherein the annular space (11) is otherwise radially defined by the cylindrical, mutually facing smooth, radially spaced surfaces of the housing (8) and the insertion part (1), wherein the at least one locking hook (4, 4') is in contact with a ring element (28) and is arranged along its circumference such that the engagement state of the at least one locking hook (4, 4') with the retaining rib (3) can be released by radial deformation of the ring element (28), wherein during a coupling state the retaining rib (3) including a retaining edge (10) of the at least one locking hook (4, 4') engaging behind it is visible in a recess (29), so that the intended locking of the at least one Locking hook (4,4') molded retaining edge (10) with the retaining rib (3) of the insert part (1) is visible from the outside, , characterized by , that the coupling element (22) consists of a ring body (15) on which at least one locking hook (4, 4') is integrally formed with an intermediate axially parallel web (26), that the ring body (15) is dimensioned with regard to centering the insertion part (1), that axially parallel tabs (17) extending in one direction away from the coupling body (2) and elastically deformable inwards are integrally formed on the ring body (15), that the tabs (17) are carriers on the outside of locking cylinders (16) which are intended for locking the coupling element (22) to the housing (8) via radial bores (19, 19'). [2] Plug-in coupling according to claim 1, characterized by, that the intended locking of the retaining edge (10) formed on the at least one locking hook (4, 4') with the retaining rib (3) of the insertion part (1) is visible from the outside and can be felt from the fact that an outer surface of the at least one locking hook (4, 4') extends flush with an adjacent edge (21) of the housing (8) of the coupling body (2) and does not project beyond the housing edge (21) of the housing (8). [3] Plug-in coupling according to claim 1 or 2, characterized by , that a free end face of the ring body (15) represents the ring shoulder (23). [4] Plug-in coupling according to any one of claims 1 to 3, characterized by , that the locking state of the coupling element (22) with the housing (8) is visually visible from the outside. [5] Plug-in coupling according to any one of claims 1 to 4, characterized by, that a distance (31) is provided axially between the mutually facing end faces (28', 17') of the ring element (28) of the tabs (17) and that the axial width of the recess (29) corresponds to the distance (31).

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