Connection system for hose lines with a lever arm coupling

0001The present invention relates to a connection system for hose lines with a lever arm coupling. Lever arm couplings for the detachable connection of hose lines in which liquids, solids and gases are conveyed are well known in the prior art. These lever arm couplings consist of a male coupling and a female coupling, which are connected to a first or second hose line or an end plug. The mother coupling has a receiving housing with a receiving area into which the male coupling fits. To attach the male coupling to the female housing, the female coupling is usually provided with two lever arms which are arranged on opposite sides of the female housing and can be pivoted between a closed and an open position. In the closed position, a pressure section of the lever arm engages through a radial opening in the receiving area of ​​the receiving housing. The male coupling has a corresponding circumferential groove, in which the pressing section of the lever arms engages with a pressing surface. In the open position, the pressure section of the lever arm does not engage in the receiving housing, so that the male coupling can be freely moved in and out of the receiving housing. This arrangement results in an effective mechanism for the quick and safe coupling and uncoupling of hose lines, for example in the document <patcit id="pcit0001" dnum="DE29707747U1"><text>DE 297 07 747 U1</text></patcit> described and defined in the European standard EN-14420-7.

0002Conventional lever arm couplings have an eccentric lever with a rounded pressure section, so that the pressure surface is moved into and out of the receiving area by rotating the lever arm. When the lever arms for coupling the hose lines are rotated, the pressure surface of the lever arm engages in the circumferential groove of the male coupling and drives the male coupling into the receiving housing until it abuts a sealing ring and is in tight connection with the female coupling. Conversely, the pressure section of the lever arm is withdrawn from the receiving area during decoupling and the father coupling is driven backwards until it is completely decoupled and can be completely pulled out of the mother coupling. If the hose lines are under pressure, there is a risk of uncoupling the pressure when the seal suddenly escapes as soon as the seal is free. The lever arms and / or the hose lines can then abruptly kick back and cause damage or even injuries. To solve this problem was in the <patcit id="pcit0002" dnum="US8123256B"><text>US 8,123,256</text></patcit> presented a lever arm coupling, the lever arms of which cannot be actuated when the hose line is under pressure. For this purpose, the lever arm coupling is provided with a cylinder in which a piston can be moved depending on the pressure in the hose line. The piston is connected to a bolt which locks a lever arm when the hose line is under pressure and releases it when the hose line is not under pressure. In the<patcit id="pcit0003" dnum="US4519635A"><text>US 4,519,635</text></patcit> a lever arm coupling with a two-stage decoupling process is introduced so that the father coupling is not immediately released when decoupled under pressure and flung directly out of the mother coupling. For this purpose, the pressure surface of the lever arm was additionally provided with a cam. If the lever arm is rotated to decouple the coupling parts, the coupling parts are slightly moved apart in a first stage and moved towards each other again in a second stage before they are completely decoupled. In the second stage of the decoupling process, the coupling parts move against the pressure direction. At high pressure, this would require an enormous force to open the lever arm completely, so that the lever arm coupling is blocked, so to speak, in this first intermediate position. For safety reasons, the decoupling of the hose lines is impossible. The operator who wants to decouple the lever arm coupling must therefore first reduce the pressure in the hose lines before he can open the coupling completely. Since the coupling is still tight in this closed position, the pressure must first be released at another point on the line. In the<patcit id="pcit0004" dnum="WO2009156357A1"><text>WO 2009/156357 A1</text></patcit> Another lever arm coupling is described, which ensures a controlled pressure relief during the decoupling process with a pressurized connection between two hose lines. For this purpose, a lock washer is also arranged next to each lever arm, with which the male coupling can be clamped in a secured pressure relief position relative to the female coupling. To solve this problem, a locking washer with a complex geometry is used in this device. Because this locking washer is an additional movable part, which is arranged on the receiving housing of the mother coupling and interacts with the male coupling and with the lever arm, both the manufacture and the mode of operation of the lever arm coupling become considerably more complicated. The present invention has as its object to improve a system of the type mentioned in such a way that the advantages of the known connection systems for hose lines with a lever arm coupling are retained, the system consists of a male coupling, a mother coupling, two lever arms and a sealing ring, the lever arms remain in the closed position due to vibrations, when opening under pressure, block the lever arms in an intermediate position and in this intermediate position the overpressure from the hose system can escape gradually and in a controlled manner via the sealing ring. This object is achieved by a connection system for hose lines with a lever arm coupling with the features of claim 1.

0003The figure shows:<dl id="dl0001" compact="compact"><dt>Figure 1a</dt><dd>Cross section of the male coupling</dd><dt>Figure 1b</dt><dd>Cross section of the nut coupling</dd><dt>Figure 1c</dt><dd>Side view of a lever arm not according to the invention</dd><dt>Figure 1d</dt><dd>Side view of the pressure section of the lever arm</dd><dt>Figure 1e</dt><dd>Cross section of the sealing ring</dd><dt>Figure 2</dt><dd>Cross section of a lever arm coupling according to the invention in the open position</dd><dt>Figure 3</dt><dd>Cross section of the lever arm coupling in the closed position</dd><dt>Figure 4</dt><dd>Cross section of the lever arm coupling in the intermediate position</dd><dt>Figure 5</dt><dd>Cross section of the lever arm coupling in a position between the intermediate position and the open position</dd><dt>Figure 6</dt><dd>Cross section of the lever arm coupling in the open position</dd></dl>

<u>Replacement page for page 6 of the description</u>

0004<dl id="dl0002"><dt>Figure 7a</dt><dd>Detailed view of the lever arm coupling near a sealing ring with a square profile, in the closed position</dd><dt>Figure 7b</dt><dd>Detailed view of the lever arm coupling near a sealing ring with a square profile, in a position between the closed position and the intermediate position</dd><dt>Figure 7c</dt><dd>Detailed view of the lever arm coupling near a sealing ring with a square profile, in the intermediate position</dd><dt>Figure 7d</dt><dd>Detailed view of the lever arm coupling near a sealing ring, in the closed position</dd><dt>Figure 7e</dt><dd>Detailed view of the lever arm coupling near a sealing ring, in a position between the closed position and the intermediate position</dd><dt>Figure 7f</dt><dd>Detailed view of the lever arm coupling near a sealing ring, in the intermediate position</dd><dt>Figure 8</dt><dd>Side view of the lever arm according to the invention</dd><dt>Figure 9a</dt><dd>Gluing the cover around the core of the sealing ring</dd><dt>Figure 9b</dt><dd>Glue the sleeve around the core of the sealing ring with the connecting layer in between.</dd></dl>

0005A lever arm coupling consists of a male coupling 1, a mother coupling 2, two lever arms 3 and a sealing ring 4 (<figref idref="f0001 f0005">Figures 1a-e</figref>). The<figref idref="f0006">Figure 2</figref> shows how these elements are assembled in the lever arm coupling. The male coupling 1 has a circumferential groove 11 and a connecting element 12 for connection to a hose line, for example a thread (<figref idref="f0001">Figure 1a</figref>). The mother coupling 2 forms a receiving area 21 into which the father coupling 1 can be inserted (<figref idref="f0002">Figure 1b</figref>). It also has two opposite radial engagement openings 22 which are provided with a pivot pin 23. The lever arms 3 have a rounded pressure section 3a, which comprises a cam 31 and a pressure surface 32 (<figref idref="f0003">Figure 1c</figref>). In the pressure section 3a there is also an opening 33 which is used to fasten the lever arms 3 to the pivot bolts 23 of the mother coupling 2. The lever arms 3 are thus arranged to be pivotable about an axis of rotation 34 which passes through the center of the opening 33 and the pivot pin 23 (<figref idref="f0004">Figure 1d</figref>). The opening 33 is arranged eccentrically in the pressure section 3a so that the thickness of the pressure section 3a is not uniform around the axis of rotation 34. In the following, four specific thicknesses of the pressing section 3a are defined in different directions around the axis of rotation 34, which are of particular interest for the invention:<ul id="ul0001" list-style="dash"><li>Thickness a: between the axis of rotation 34 and the pressure surface 32;</li><li>Thickness b: between the axis of rotation 34 and the pressure surface 32 in the vicinity of the cam 31;</li><li>Thickness c: between the axis of rotation 34 and the extreme end of the cam 31;</li><li>Thickness d: between the axis of rotation 34 and the edge of the pressure section 3a on the other side of the cam 31.</li></ul>

0006Like in the <figref idref="f0004">Figure 1d</figref> can be seen, the relative sizes of these thicknesses a, b, c and d are as follows: a> c> b> d. Depending on the position of the lever arm 3 around the pivot pin 23, the pressure section 3a thus engages more or less deeply through the radial engagement opening 22 in the receiving area 21 of the mother coupling 2 (<figref idref="f0007 f0008 f0009">Figures 3-5</figref>). In the open position of the<figref idref="f0006">Figure 2</figref> the pressure section 3a has a thickness d from the axis of rotation 34 and in the direction of the receiving region 21. According to the invention, this thickness d is sufficiently small so that the pressure section 3 a does not engage in the receiving housing 21 and the male coupling 1 can be freely inserted and carried out in the female coupling 2. To couple the hose lines, the male coupling 1 is inserted into the receiving area 21 of the female coupling and the lever arms 3 are pivoted from the open position to the closed position (FIG. 3). In the closed position, the pressing section 3a has a thickness a from the axis of rotation 34 and in the direction of the receiving region 21. The pressure surface 32 engages in the corresponding circumferential groove 11 of the male coupling, whereby the male coupling is firmly and securely anchored in the receiving area 21 of the female coupling. It is important for the tightness of the connection between the coupling parts 1-2 that the male coupling 1 not only slightly abuts the sealing ring 4 in the closed position, but presses it against the female coupling 2.

0007It is provided that the decoupling of the lever arm coupling is carried out according to a two-stage process. In the first stage of the decoupling process, the lever arms 3 are from the closed position of the<figref idref="f0007">Figure 3</figref> to the intermediate position of the <figref idref="f0008">Figure 4</figref> pivoted. In the intermediate position, the pressing section 3a has a thickness b from the axis of rotation 34 and in the direction of the receiving region 21. Since the thickness b is smaller than the thickness a of the closed position, the grip loosens around the circumferential groove 11 of the male coupling 1, so that the coupling parts 1-2 move apart slightly. If the hose lines are under pressure, this movement apart occurs spontaneously until the male coupling 1 of the projecting cam 31 is in the intermediate position <figref idref="f0008">Figure 4</figref> is blocked. To complete the decoupling, the lever arms 3 are further from the intermediate position<figref idref="f0008">Figure 4</figref> to the position of the <figref idref="f0009">Figure 5</figref> turned around. In this position, the pressure section 3a has a thickness c from the axis of rotation 34 and in the direction of the receiving region 21. Since the distance c is greater than the distance b of the intermediate position, the coupling parts 1-2 are pushed slightly towards each other again (<figref idref="f0009">Figure 5</figref>) before they are completely decoupled in the subsequent open position (<figref idref="f0010">Figure 6</figref>).

0008In summary, the male coupling is not moved directly out of the housing when decoupling, but:<ul id="ul0002" list-style="dash"><li>in a first stage: first moved slightly outwards from the closed position to the intermediate position;</li><li>in a second stage: then moved slightly inwards from the intermediate position;</li><li>and finally completely decoupled in the open position, whereby it can be completely pulled out of the mother coupling.</li></ul>

0009If the hose lines are under pressure, the first stage of the decoupling process is effortless because the pressure drives the coupling parts 1-2 apart. In the second stage of the decoupling process, however, the coupling parts 1-2 are moved towards each other again, ie counter to the pressure direction. A deflection of the lever arms 3 and the coupling parts 1-2 from the intermediate position of the<figref idref="f0008">Figure 4</figref> is therefore excluded since each movement of the lever arms 3 entails a deeper engagement of the pressure surface 32 or of the cam 31 in the receiving area 21 and the coupling parts 1-2 are moved against the pressure force. If the hose lines are under high pressure, the coupling parts 1-2 are pressed apart so violently that an operator can only pull them apart with great force using the lever arms 3. In the intermediate position, the lever arm coupling is blocked.

0010Accordingly, the invention provides for the excess pressure to escape from the hose system in the intermediate position via the sealing ring 4. For this purpose, the connection between the mother and father coupling is made leaky, ie that a passage is made possible which allows the excess pressure between the sealing ring 4 and the coupling parts 1-2 to escape. In conventional lever arm couplings, sealing rings 4 with a square or rectangular profile are used, which in the closed position have the largest possible contact surface with the coupling parts 1-2 and thus ensure a good seal of the connection (<figref idref="f0011">Figure 7a</figref>). When the coupling parts 1-2 are moved apart from the closed position to the intermediate position, the compressed sealing ring 4 expands (<figref idref="f0011">Figure 7b</figref>). The sealing ring 4 with a square or rectangular profile expands laterally evenly and the contact surface with both coupling parts 1-2 remains the same. Despite the movement of the coupling parts away from each other, the connection remains tight as in the closed position until the sealing ring 4 regains its original shape, separates from the coupling parts 1-2 and the connection suddenly becomes completely leaky (<figref idref="f0011">Figure 7c</figref>).

0011In the present invention, the overpressure is to escape gradually and in a controlled manner from the hose system via the sealing ring in the intermediate position. This is achieved in that the sealing ring 4 and the male coupling 1 are not suddenly separated. Rather, the contact area between the sealing ring 4 and the male coupling 1 is gradually reduced, so that the tightness of the connection gradually decreases and the excess pressure can gradually escape.

0012It is planned to use a sealing ring 4 with a round profile in the lever arm coupling (<figref idref="f0012">Figure 7d-f</figref>). During the movement of the coupling parts 1-2 from the closed position (<figref idref="f0012">Figure 7d</figref>) to the intermediate position (<figref idref="f0012">Figure 7e</figref>) the compressed oval sealing ring 4 expands laterally so that the contact area to the two coupling parts is reduced, since the sealing ring 4 returns to its original round shape. The tightness of the connection gradually decreases and the overpressure from the hose line can be reduced slowly and in a controlled manner. Impacts and rapid movements of the coupling parts and lever arms can thus be avoided. In order to achieve a sufficient tightness of the connection in a round sealing ring 4, sealing rings 4 with a larger diameter than the standard sealing ring with a rectangular profile are preferably to be used, which are then compressed and deformed more strongly between the two coupling parts 1-2. Conversely, it is theoretically also possible to round off the extreme end of the male coupling 1 instead of using a sealing ring 4 with a round profile in order to achieve the same effect. A modification of the male coupling 1 is undesirable since the male coupling is a standardized standard component. Therefore, it is provided according to the invention to improve the design of the lever arm or arms 3 of the mother clutch 2, which control the father clutch 1 directly. These can be replaced on an existing standard coupling with relatively little effort. The lever arm 3 is adapted in such a way that a cam 31, as is known from the prior art, of the lever arm 3 is rounded off, so that the cam 31 has a curved but tapering shape and is not angular from the pressure section 3a of the lever arm 3 protrudes (<figref idref="f0013">Figure 8</figref>). The expression “lever arm 3 with curved cams 31” is to be understood as a lever arm 3, the pressure surface 3a of the lever arm 3 always being tangentially in contact with the male coupling between the closed position and the intermediate position. Conventional angular cams 31 cause the coupling parts 1-2 to be thrown abruptly and away from one another with great force. The subsequent stopping of this deflection in the blocked intermediate position can trigger a kickback effect in the line, which could damage the lever arm coupling, the hose lines and any valves. In addition, the movement apart from the closed position with complete tightness to the intermediate position with complete separation between the sealing ring and the coupling parts 1-2 takes place at once, so that the excess pressure suddenly escapes. With a curved cam 31, the male coupling is gradually moved out of the female coupling before it is completely blocked at the tip of the cam 31. Thus, the contact area between the sealing ring 4 and the male coupling 1 decreases only gradually, which ensures a slow and controlled pressure release. Since the sealing ring 4 does not seal completely before reaching the blocked position and also in this position, the overpressure in the line can be reduced until the lever arm can be moved over the tapering part without excessive force, so that the coupling is complete is open.

0013In a variant of the lever arm coupling, the sealing ring 4 comprises a core 41 made of elastic material (<figref idref="f0005">Figure 1e</figref>) such as rubber or caoutchouc, for example made of Viton®. The elastic core material 41 is used so that the sealing ring 4 can be strongly compressed so that it is strongly deformed in the closed position between the coupling parts 1-2 and the connection surface to the coupling parts is as large as possible, so that a tight connection is created. However, elastic materials such as rubber usually have a high coefficient of friction and therefore adhere to the coupling parts 1-2. There is therefore still the risk that such sealing rings 4 stick to one another during the movement of the coupling parts 1-2, stick to the male coupling 1 and only come off suddenly and intermittently, which in turn can lead to blows. It is also possible that a sealing ring 4 with a round profile can rotate, so that the elasticity becomes irregular, or the ring can even be moved away from the desired position. In order to allow the excess pressure to escape in a controlled manner, it therefore makes sense if the seal ring's adhesion is reduced. A particularly advantageous embodiment variant therefore provides that the core 41 of the sealing ring 4 is surrounded by a sleeve 42 made of a second material which is less adhesive and has a low coefficient of friction. For example, non-porous PTFE (Teflon) is a good choice of material because PTFE fulfills these criteria and also has excellent chemical inertness. This has the additional advantage that the sealing ring does not, or only slightly, wear even with highly reactive media which are conveyed through the hose lines and has a long service life.

0014In one possible manufacturing process, the sleeve 42 is wrapped around the sealing ring 4 and glued (<figref idref="f0014">Figure 9a</figref>). On one side of the sealing ring 4, both ends of the sleeve 42 are glued or welded together seamlessly. However, due to the well-known non-stick effect of PTFE, it is difficult to glue or weld two PTFE parts sufficiently firmly. Due to the high pressure and the repeated deformations of the sealing ring 4, the risk that the connection between the two ends of the sleeve 42 will gradually dissolve or even suddenly burst open. To avoid this, the connection must be very strong. When gluing or welding, it must be ensured that the adhesion is sufficiently strong. This liability can be improved if the surfaces to be glued are processed beforehand. For example, they could be roughened, grooved, or chemically processed. In addition, a special adhesive or an intermediate layer can be used to strengthen the connection. In one embodiment variant it is provided that the connection between the two ends of the casing 42 is reinforced with an intermediate connecting layer 44 (<figref idref="f0015">Figure 9b</figref>). This connection layer 44 can consist of perfluoroalkoxy alkane (PFA), for example.

0015Since the sealing ring is made of a material that is not very adhesive and because of the round profile it does not fit exactly into the recess in the nut coupling, it can slip under certain circumstances or not lie at the same distance from the outer edge over the entire circumference, which has a negative influence on the seal may have. It is therefore provided in a further embodiment variant that the sealing ring has a radial spacer 43 so that it is centered at the correct and above all even distance from the side walls of the nut coupling (<figref idref="f0006 f0007 f0008 f0009 f0010">Figures 2-6</figref>). This spacer 43 can, for example, be a projecting part of the casing 42 (<figref idref="f0014 f0015">Figures 9a-b</figref>). Preferably, the glued part of the sleeve 42 can simultaneously form the spacer 43.