Two-piece screw nut and set containing one such screw nut

Abstract

Screw nut (1) with an internal thread and two nut parts (2, 3), wherein each of the nut parts (2, 3) has a section (4, 5) of the internal thread which can be slid onto an external thread (30) in a radial direction, and wherein the nut parts (2, 3) have interoperable connecting elements which allow a relative displacement of the nut parts (2, 3) in a direction radial to the axis of the internal thread to a position in use in which the internal thread of the screw nut (1) engages the external thread (30) with minimal play, wherein the connecting elements have guide surfaces (14 - 25) which guide the nut parts (2, 3) of the screw nut (1) in a rotational movement about an axis of rotation extending transversely to the axis of the internal thread when moving into the use position, wherein each nut part (2, 3) has at least one first locking arm (10, 13) which has a guide surface (14, 17) on one side which causes the rotational movement when the nut parts (2, 3) are moved and bears against a complementary guide surface (16, 15) on a second locking arm (12, 11) of the other nut part (3, 2), and wherein the screw nut (1) in the use position of the nut parts has a shoulder surface (26) extending towards the axis of the internal thread in the region of a first end of the internal thread, characterized by the fact that the shoulder surface (26) deviates from a plane extending radially to the axis of the internal thread and is such that the radially outer region of the shoulder surface (26) with the greatest distance to the axis of the internal thread has the greatest axial distance from the second end of the internal thread and the inner region of the shoulder surface (26) with the smallest distance to the axis of the internal thread has the smallest axial distance from the second end of the internal thread.

Description

[0001] The invention relates to a screw nut with an internal thread and two nut parts according to the preamble of claim 1.

[0002] Multi-part nuts have been known for a long time. For example, German patent DE 1 144 542 A from 1963 describes a nut according to the general term. In describing the prior art, it refers to split nuts that have conical or cylindrical projections which are encompassed by corresponding countersinks of closed rings or by the objects to be fastened. US patent 2 789 458 A describes such a two-part nut that is sleeve-shaped with a conical outer surface, wherein the outer surface has a threaded section extending axially from the conical section. A threaded sleeve is screwed onto this threaded section, the annular inner surface of which rests against the conical outer surface and presses the two nut parts together. German patent DE 25 46 831 A1 describes a nut whose nut parts have a projection that is initially cylindrical and conical towards the axial end.This component is screwed into a bore, which compresses the nut parts. DE 1 144 542 A aims to avoid such conical outer surfaces.

[0003] Such a two-part screw nut is known from European patent EP 1 982 082 B1. The disclosure of that patent is incorporated into the present application by reference. The screw nut described in that patent is described in detail below.

[0004] The two nut parts of the screw nut are fitted with interacting connecting elements and guide surfaces. In the operating position of the nut parts, these elements interact in such a way that radial displacement of the nut parts away from the operating position and from the external thread is blocked. To reach the blocking operating position, the nut parts are not only displaced radially but also rotated or pivoted about an axis of rotation perpendicular to the axis of the internal thread. This rotational movement is only possible when the screw connection is loosened. When the screw connection is tightened, the screw nut rests with one or more contact surfaces on an opposing support surface that is axially fixed to the external thread. At least one nut part has at least one locking arm.The locking arm has two sides oriented in opposite directions relative to the thread axes. These sides can also be referred to as the top and bottom, assuming the thread axis runs from top to bottom. Only one of these two sides of the locking arm has a guide surface that facilitates rotation, bearing against a complementary and oppositely oriented guide surface of the other nut part. In practice, the other side of the locking arm can form the outer or axial end face of the nut part (top or bottom) and rest against a support surface of a component against which the nut is tightened.

[0005] The locking arm with its guide surface on the first nut part, as well as the interacting material section of the second nut part, can have considerable material thicknesses. It is possible for the material thickness of these sections to correspond to half the total thickness of the nut. This results in high stability and load-bearing capacity for these material sections and thus for the nut as a whole. Furthermore, the guide surface of the locking arm and the interacting guide surface can extend over the entire length of the nut. This provides a large bearing surface and therefore high load-bearing capacity.

[0006] If the bearing surface of the nut, which is formed by its underside when screwed onto a vertical external thread with a support surface on the underside, rests against the support surface when tightened, the pivoting of the nut parts is blocked, and the nut can only be loosened by unscrewing it from the external thread of the screw or threaded rod. However, if, after being loosened by a few turns, the nut has a certain distance from the support surface, the nut parts can rotate or pivot and then be separated from each other radially along the thread.

[0007] It should be noted that the axis of rotation, which runs perpendicular to the axis of the internal thread, does not necessarily have to be perpendicular to the axis of the internal thread. It can also be inclined or skew with respect to the axis of the internal thread. In practice, however, the axis of rotation will usually be approximately radial to the axis of the internal thread.

[0008] In other words, when the nut is pushed onto the external thread and pivoted, it has one or more thread turns away from the opposite support surface. By tightening the nut by the number of turns corresponding to the number of threads, the nut braces itself against the opposite support surface, thus preventing the nut parts from pivoting again and from separating from each other. The assembly of the nut parts is facilitated by a guide surface on one side of the locking arm, which facilitates the rotation of the nut parts.The opposite side of the locking arm, that is, the side of the locking arm oriented opposite to the guide surface with respect to the thread axis, forms an outer surface of the nut on its top or bottom and can bear against a support surface when tightened. Since the locking arm interacts with an opposing support surface on one side to achieve the rotational movement, its thickness is not critical and does not need to adhere to specific manufacturing tolerances.

[0009] The pivoting or rotating movement of the nut parts around an axis perpendicular to the axis of the internal thread when the nut parts are fitted onto the external thread ensures that counter-rotation is blocked once the nut parts are tightened. The resulting nut is thus permanently fixed to the external thread.

[0010] This type of nut offers significant handling advantages over conventional nuts. It is not necessary to screw the nut onto the entire external thread. To install it, the nut simply needs to be slid radially onto the thread, pivoted, and then tightened a few turns. Alternatively, both parts of the nut can be held in a partially compressed position, allowing them to be slid along the external thread to the desired position. Only then are the nut parts pressed against each other into the operating position and finally screwed firmly onto the external thread.

[0011] It is also possible to attach a two-part nut to an external thread without a free end. For example, the nut can be fitted onto a threaded section that is bordered on both sides by thicker, unthreaded rod sections. The two-part nut thus enables exceptional connection types, while being easy to handle and cost-effective to manufacture.

[0012] In practice, the connecting elements of the nut parts comprise guide surfaces that rest against each other and effect rotation, and which are inclined at an angle to the plane extending radially to the axis of the internal thread. This angle of the guide surfaces to the radial plane of the internal thread means that the nut parts of the screw nuts are not simply moved radially against each other, but must also be pivoted about an axis essentially in a radial plane of the internal thread.

[0013] In practice, the guide surfaces are preferably inclined at an angle of less than 20° to the radial plane of the internal thread. This prevents the pivoting movement required to connect the nut parts from becoming excessive and avoids collisions between the threaded sections of the nut parts and the external thread during this movement. If larger inclinations were required, the colliding contours of the threaded sections would have to be machined away. However, the guide surfaces can also have a variable inclination to the radial plane and, for example, be cylindrically curved or helically wound.

[0014] To achieve pivoting motion, the guide surfaces can be arranged in various ways. In a nut where the internal thread sections of the two nut parts are separated along a parting plane extending in the direction of the thread axis, each nut part can have two guide surfaces arranged on either side of a median plane perpendicular to the parting plane. If the direction in which the guide surfaces extend is called the longitudinal direction, the median plane forms the central longitudinal plane, with the two guide surfaces extending on either side of this median plane. Furthermore, the two guide surfaces of a nut part can be oriented in opposite directions with respect to the thread axis.Assuming the thread axis runs from top to bottom, the surface normal of the first guide surface of one nut part points upwards, and the surface normal of the second guide surface of the same nut part points downwards. The complementary nut part is designed accordingly. At least one nut part with the guide surfaces is located on the locking arms. This design of the inclined guide surfaces can, with a suitable guide surface profile, lead to the pivoting movement. For example, the guide surfaces can lie on a helical surface wound around a radial axis located in the central plane, which dictates a screwing motion when the two nut parts are pushed together. The two guide surfaces can also lie on a cylindrical surface whose cylinder axis lies in the parting plane. In this case, the nut parts pivot relative to each other about the cylinder axis when pushed together.

[0015] Alternatively, a nut consisting of two nut parts, whose internal threaded sections are separated along a parting plane extending in the direction of the thread axis, can have flat guide surfaces that are neither curved nor helical. To create the pivoting motion, each nut part can have two guide surfaces located on either side of the parting plane. The first guide surface on the first side of the parting plane can be oriented in a first direction with respect to the thread axis, and the second guide surface on the second side of the parting plane can be oriented in a second direction opposite to the first. In other words, the guide surfaces of a nut part on the first side of the parting plane point upwards and those on the second side of the parting plane point downwards when the thread axis runs vertically from top to bottom.Furthermore, the guide surfaces on the first side of the division plane are inclined in the opposite direction to the radial plane of the thread than those on the second side of the division plane. In other words, the planes in which the guide surfaces lie are shaped like a pitched roof, the gable of which lies on the thread axis. This allows the nut parts to be slid into one another, with the axes of the internal thread sections of the nut parts slightly pivoted relative to each other. In the final stage of the sliding movement, the nut parts are pivoted into the operating position about a pivot axis extending radially to the thread axis and lying in the division plane. In the operating position, the axes of the internal thread sections of the two nut parts are essentially aligned, and the internal thread consisting of the two sections engages an external thread of corresponding dimensions with essentially no play.Then the resulting nut can be tightened.

[0016] As mentioned, the guide surfaces can have a curvature in the form of a cylindrical segment. The guide surface on the first nut part is convex, and the interacting guide surface on the second nut part is concave, corresponding to the same cylindrical surface. This allows the approach movement of the two nut parts to be guided along a longer path of motion along the aforementioned cylindrical surface.

[0017] In practice, the axis of the internal thread can intersect the axis of the cylinder on whose outer surface the guide surfaces run. Alternatively, the division of the nut parts can lie in a plane that intersects the cylinder diametrically. The rotation of the nut parts during movement into the operating position then occurs through the displacement of the cylindrical guide surfaces relative to each other, essentially around the axis of the cylinder's outer surface, which lies in the plane of the division of the nut parts.

[0018] As mentioned above, in another practical embodiment the guide surfaces can lie on a helical surface. The coil runs, for example, around an axis that is perpendicular to the plane of the nut's division and radial to the axis of the internal thread, intersecting the thread axis approximately in the middle of the internal thread. In this case, when assembling the nut parts, they are not rotated around an axis lying in the division plane, but rather around an axis perpendicular to the nut's division plane along a screw motion.

[0019] In practice, the material of the nut, usually steel but also plastic depending on the application, can be elastically deformable. The shape of the two opposing guide surfaces of the nut parts can differ slightly. The surfaces may be slightly differently curved or inclined towards each other. Both characteristics result in a certain degree of deformation of the nut parts when the pressure acting in the direction of the internal thread is increased by tightening the nut, until the guide surfaces make full contact with each other. The guide surfaces of the nut parts then function as a washer or spring washer and additionally secure the screw connection against loosening due to dynamic load changes. The same applies if the underside of the nut parts only rests on the underlying support surface at one or two contact points.The bearing surface is the surface fixed axially to the external thread against which the nut is supported when tightened. If this support is provided by only one or two contact points per nut part, tightening generates a torque that elastically deforms the nut parts slightly and causes them to tilt. The nut is thus under elastic tension, similar to when using a washer. Under dynamic loading of the screw connection, this tension causes the screw to self-lock.

[0020] Additionally, the connecting elements of the nut parts can have mutually abutting guide surfaces that lie in a plane extending parallel to the axis of the internal thread. This plane, extending parallel to the axis of the internal thread, preferably defines the direction of the radial displacement of the two nut parts relative to each other. The additional guide surfaces thus guide the nut parts in the radial direction of the thread, but not the rotational movement. Furthermore, additional guide surfaces in an axial plane (also called the vertical plane) form the stops effective in the operating position for the displacement of the nut. As mentioned, these additional guide surfaces do not cause the nut parts to pivot to reach the operating position and consequently do not contribute to locking the nut parts together.

[0021] As mentioned, the connecting elements, which necessitate pivoting the nut parts to reach their operating position, prevent the nut from pivoting during tightening because its contact surface rests against a support surface connected to the external thread. The contact surface of the nut need not be continuous. It is sufficient if each nut part has at least one, preferably two or three, contact points that bear against the support surface, which is axially fixed to the external thread, during tightening. In the nuts known from EP 1 982 082 B1, the contact surface is formed on the side of the locking arm opposite the guide surface that effects rotation.

[0022] The contact surface of each nut part can have an inclined plane at one edge, which defines the angle of the nut part's pivoting movement. This inclined plane has an angle to the contact surface that corresponds to the rotation angle of the respective nut part when it is moved into its operating position. In other words, the two nut parts can be pivoted by applying pressure to their edges through an angle corresponding to the pivot angle from the assembly position to the operating position. In this pivoted state, the nut parts can be slightly pushed into each other by the support surface. In the final stage of the movement, the nut parts are pivoted into their operating position and then tightened, being locked in place by the support surface of the nut's contact surface against the support surface.

[0023] Similarly, a nut with a point-like contact surface can be designed. A contact point of one nut part should, together with at least two other points in the edge region of the nut part, define an inclined surface whose angle corresponds to the angle of rotation by which the nut part is turned during assembly. Again, pressing on the edge region allows the nut part to pivot into the assembly position. In this position, the nut part can be pushed a certain distance into the complementary nut part. Subsequently, the manual pivoting motion is performed, whereby the threaded sections of both nut parts engage with the external thread, and the operating position is reached.

[0024] In practice, at least one of the nut parts may have threads removed at at least one end of the internal thread section to allow rotation of the nut parts during the pivoting movement into the operating position. Depending on the chosen path of movement of the relative motion of the nut parts, removing threads prevents the closing movement from becoming blocked. During the pivoting movement, the internal thread sections may slightly abut the external thread, necessitating elastic deformation of the nut parts during the closing movement into the operating position. This causes the nut parts to snap onto the external thread and can only be removed by applying increased force, which induces the aforementioned elastic deformation.

[0025] The two-part nut can, of course, also feature a self-tapping thread. The material removal in the threaded area can be designed so that the thread cuts the threads of the external thread like a tap. This would allow the nut to be used even more effectively on flexible, unthreaded materials, such as plastic rods or plastic-coated cables, for example, as strain relief for electrical cables.

[0026] Through a special design of the nut, the two parts of the nut can be identical. This is readily possible, for example, with a double-start thread if the nut parts are rotationally symmetrical, meaning they are identical to each other when rotated 180°, with respect to the thread axis or an axis of symmetry extending in the plane of the nut pitch and radially to the thread axis. With a conventional single-start thread, the identical nut parts can be rotationally symmetrical with respect to an axis of symmetry lying in the plane of the nut pitch and extending radially to the thread axis. The nut parts preferably have an upwardly directed and a downwardly directed inclined surface, which are arranged on two locking arms extending perpendicular to the plane of the nut pitch and which act as connecting elements.These inclined surfaces align with the opposing inclined surfaces of the complementary nut part during connection. The nut parts are then slid towards each other and twisted together in a screw-like fashion.

[0027] A screw nut consisting of two identical nut parts has the advantage of being very cost-effective to manufacture in large quantities. In particular, each nut part can be produced in a single compression molding process. Furthermore, the user can join any nut parts together without having to search for two matching parts.

[0028] With nuts that have a single internal thread and may appear symmetrical externally, but whose threads are not symmetrical, as well as with asymmetrical nut parts, there is a risk that the user will attempt to assemble the nut parts incorrectly. The top and bottom surfaces of such nut parts may be additionally marked, for example, by notches or other markings, to prevent assembly errors. Incorrect assembly can also be prevented by appropriately shaping the connecting elements, whereby external symmetry exists only with respect to one axis and is eliminated with respect to the second axis through different designs of the guide surfaces. In this case, the nut parts obviously cannot be assembled incorrectly.

[0029] Additionally, the nut parts can include interlocking retaining elements that fix these nut parts together in the operating position or shortly before, that is, in a position that is at least partially compressed. Without such retaining elements, there is a risk that the nut parts will unintentionally separate when the nut is screwed onto the external thread, as long as the contact surface is not firmly pressed against the support surface.

[0030] The retaining elements can be formed, for example, by mutually attracting magnets or by a magnet and a ferromagnetic material section. However, interlocking retaining elements such as detent projections and complementary detent recesses are also possible, ensuring that the nut parts of the screw / nut lock into place in the operating position. The fixing of the nut parts to the external thread or to each other can also be achieved by other suitable measures, in particular by shaping the connecting elements (undercuts, deformation of the nut, friction / tension on the external thread and between the parts).

[0031] The two-part nut can be used as follows. When the nut parts are pushed together radially, in addition to the displacement of the nut parts, a rotation or pivoting of the nut parts occurs at least in the last part of the movement, shortly before the use position, about an axis of rotation running transversely to the axis of the internal thread.

[0032] During this rotation, two complementarily curved guide surfaces of the nut parts can slide against each other.

[0033] As mentioned, each of the nut parts can be placed on a support surface connected to the external thread by means of an inclined surface located in its edge area. This causes the nut parts to be inclined relative to each other, which facilitates their interlocking. The nut parts are thus moved towards each other in an assembly position in which their connecting elements engage and subsequently guide the further movement of the nut parts.

[0034] Finally, EP 1 982 082 B1 discloses a tool for attaching a screw nut of the type described above. This tool has a holding device for each nut part of the screw nut. The holding devices are coupled to one another via drive means, in particular articulated connections and lever connections, such that they either actively execute or at least passively permit the displacement and pivoting movement of the nut parts. First, they execute a displacement movement relative to each other in a direction radial to the axis of the internal thread. Subsequently, at least in the last phase of the movement, before the nut parts have reached their operating position in the screw nut, they execute a pivoting or rotational movement about an axis of rotation transverse to the axis of the internal thread.For this purpose, the holding devices can either be driven in the predetermined path of movement or at least have the necessary degrees of freedom through joints.

[0035] To open the nut, the tool can perform a counter-rotating movement. The tool can, for example, be designed like a pair of pliers, with the holding devices forming the two jaws of the pliers. These are driven by the two levers of the pliers via a gearbox such that the pivoting or rotational movement required to reach the operating position is executed. Particularly with nut components that have retaining elements, the tool can ensure that the holding force of the retaining elements is reliably overcome to release the nut components if manual removal of the nut components from the external thread is not possible.

[0036] The screw nut described above, part of EP 1 982 082 B1, enables durable and secure screw connections in a wide variety of applications. The axial clamping force of this screw nut achieves values ​​essentially equivalent to those of conventional screw nuts.

[0037] The screw nut of EP 1 982 082 B1 can have a shoulder surface extending towards the axis of the internal thread at one end of the internal thread. This shoulder surface preferably has an annular shape projecting towards the center of the internal thread and is arranged halfway on each part of the nut. The radially inwardly projecting shoulder surface can, like a cap nut, engage a radial shoulder of an object to be screwed onto an external thread, e.g., a pipe fitting, and press against an end face of the external thread when tightened. The radial shoulder surface can be formed by a wall of a groove adjoining the internal thread. Unlike conventional screws, it is not necessary for the radial shoulder of the object to be screwed on to be pushed through the internal thread before it abuts the inwardly projecting shoulder surface.The radial shoulder of the object can be inserted into a groove when the nut is slid together, where the radial shoulder is received with minimal play. Therefore, it is not necessary for the radial shoulder and the groove or the shoulder surface of the nut to be round. They can have complementary shapes that deviate from a round form and fit together positively when the nut parts are slid together.

[0038] The practical implementation of such a union nut according to EP 1 982 082 B1 presents the challenge of creating a reliable and durable connection.

[0039] This problem is solved according to the invention by the shoulder surface deviating from a plane radially extending to the axis of the internal thread and extending in such a way that the outer region of the shoulder surface with the greatest distance to the axis of the internal thread has the greatest axial distance from the second end of the internal thread and the inner region of the shoulder surface with the smallest distance to the axis of the internal thread has the smallest axial distance from the second end of the internal thread.

[0040] In other words, the annular shoulder surface, which extends radially inwards towards the axis of the internal thread at one end, deviates from a radial plane of the thread. A shoulder surface extending radially and thus perpendicular to the axis of the internal thread – as described in EP 1 982 082 B1 – is sufficient for small axial forces, particularly when the overall material thickness of the nut is small and the planes of action of the force vectors of the thread's supporting forces and the supporting forces of the shoulder surface are close to each other. With large nuts, where the points of application of the supporting forces are considerably far apart, the supporting forces can lead to unacceptably high deformations, which can compromise the reliable function of the two-part nut. For this reason, the annular shoulder surface deviates from a radial plane in such a way that it engages behind the thread in a radial direction.The radially outer region of the shoulder surface therefore has the greatest axial distance from the second end of the nut's internal thread, and the radially inner region of the shoulder surface has the smallest axial distance from the second end of the internal thread. A complementary support surface of a component fixed by the nut, interacting with the shoulder surface, consequently engages behind the outer region of the shoulder surface. In this type of cap nut, the shoulder surface thus forms the bearing surface of the nut, which, when the nut is tightened, is pressed axially against a support surface connected to the external thread, thereby fixing the two parts of the nut together.

[0041] In practice, if the shoulder surface is a conically concave annular surface, the nut parts are compressed towards the axis of the internal thread when tightened. The conical inclination causes the two nut parts to be pressed into a position closer to each other. However, the shoulder surface can also be stepped, with an annular ridge formed in its radially inner area, which is engaged by a complementarily shaped support surface. The inclination and engagement of the shoulder surface counteract any opening movement of the nut parts. The nut serves to fasten a component with a shank section that can be gripped by the assembled nut. As explained above, the two nut parts can be pushed together, gripping this shank section as well as an external thread onto which they are to be screwed.Adjoining the shank section is an outwardly projecting support surface for the shoulder of the nut. This support surface generates axial pressure that secures the two parts of the nut in the compressed position, also known as the operating position. Additionally, this support surface can be inclined relative to the radial plane, corresponding to the shoulder of the nut, such that the shoulder is coplanar to the support surface when the nut is compressed. In this case, the support surface is, for example, funnel-shaped and is engaged radially by the shoulder of the nut. This pulls the two parts of the nut together radially and secures them in the operating position.This increases the load-bearing capacity and safety of the connection created by the union nut with the component and the interacting external thread.

[0042] In practice, the average inclination of the shoulder surface in an axial section plane can be at least 30°. This generates a total force through axial pressure of the shoulder surface against a complementary support surface, which has an axial component and a component that radially compresses the nut parts, thus ensuring optimal hold of the assembly.

[0043] In practice, the shoulder surface can extend along a ring of a conical surface. This embodiment should be selected when the shoulder surface of the nut surrounds a circular hole and the shank section of the component fastened by the nut is cylindrical. The shape of the shank section and the hole of the nut can also deviate from a circular shape in axial plan view and, for example, be square. In this case, when the nut is turned relative to the external thread to which it interacts, the component with its shank rotates together with the nut.

[0044] As mentioned above, in practice the opposing and interacting guide surfaces can include retaining elements (projections and recesses) that fix the nut parts together in a partially compressed position. In this way, the two nut parts and the component whose shank the nut parts enclose can be combined to form a slightly open nut, whose internal thread can be slid over a complementary external thread. The two nut parts can then be pressed together so that the internal and external threads engage, and the nut can be tightened onto the external thread.

[0045] The invention further relates to a set comprising a screw nut as described above and a component with a shaft section that can be grasped by the assembled screw nut, wherein an outwardly projecting support surface for the shoulder surface of the screw nut adjoins the shaft section, which is inclined to the radial plane in such a way that the shoulder surface is coplanar to the support surface in the assembled state of the screw nut.

[0046] A practical embodiment and further advantages of the invention are described below in connection with the drawings. Fig. Figure 1 shows a three-dimensional side view of a screw nut with two nut parts. Fig. 2 shows the two mother parts made of Fig. 1 in a slightly rotated version for better illustration of in Fig. 1. Hidden areas of the mother parts. Fig. Figure 3 shows a three-dimensional oblique side view of two components to be joined together, namely a pipe end with external thread and a plug. Fig. 4 shows the plug made of Fig. 2 together with the two-part screw nut made of Fig. 1 and Fig. 2 in open position. Fig. 5 shows the arrangement from the Fig. 4 with partially closed screw nut and additionally with the pipe end. Fig. Figure 6 shows the arrangement of Fig. 5 with fully closed screw nut. Fig. Figure 7 shows a longitudinal section through the arrangement made of Fig. 6.

[0047] The Fig. Figure 1 shows a side view of a two-part screw nut 1 of the design described in EP 1 982 082 B1, in particular in the Fig. 32 of this patent specification. The screw nut 1 consists of two nut parts 2, 3, which are shaped to complement each other. The Fig. Figure 2 shows the two mother parts 2, 3 opposite each other. Fig. 1. From a different perspective and slightly turned towards the viewer. The nut parts 2, 3 can be fitted together in such a way that they surround an external thread with minimal play. This position of the nut parts 2, 3 of the screw nut 1 is referred to in this description as the operating position. Each of the nut parts 2, 3 has an internal thread section 4 or 5, respectively. The internal thread sections 4, 5 together form an internal thread which, in the fitted operating position of the nut parts 2, 3 (see e.g. Fig. 6) surrounds the external thread with a small amount of play.

[0048] Each internal thread section 4, 5 extends over 180° of the internal thread. The internal thread sections 4, 5 are separated from each other in a plane which, in the operating position where the nut parts 2, 3 closely surround the external thread, contains the thread axis.

[0049] Both nut parts 2, 3 have stop surfaces 6, 7, 8, 9 which run in the division plane of the internal thread. These stop surfaces 6 - 9 are located in the operating position ( Fig. 6) against each other. In this operating position, the internal thread is closed, and its threads surround the threads of the external thread with a normal thread clearance.

[0050] In the Fig. 1 and Fig. Figure 2 shows four locking arms 10, 11, 12, 13. Two of the locking arms 10, 11 are arranged on the first nut part 2 and extend essentially perpendicular to the stop surfaces 6 and 7. The two further locking arms 12 and 13 are provided on the second nut part 3 and extend essentially perpendicular to the two stop surfaces 8 and 9.

[0051] Each of the locking arms 10 and 11 of the first nut part 2 has a substantially cylindrically curved guide surface 14, 15. The first guide surface 14 has in Fig. 1 downwards. The second guide surface 15 points in the opposite direction, i.e. inwards. Fig. 1 upwards. Both guide surfaces 14, 15 lie on the same cylindrical surface. The locking arm 10 with the first downward-facing guide surface 14 is opposite the locking arm 12 of the second nut part 3 with an upward-facing guide surface 16, which is cylindrically curved with a complementary profile. The locking arm 11 of the first nut part 2 with upward-facing guide surface 15 is opposite a locking arm 13 of the second nut part 3 with a downward-facing guide surface 17, which also runs along a section of the aforementioned cylindrical surface.

[0052] The locking arms 10-13 and the nut parts 2, 3 further have flat guide surfaces 18-25, which each extend in planes perpendicular to the dividing plane of the nut parts 2, 3 and guide the nut parts 2, 3 together. During connection, the nut parts 2, 3 are pushed towards each other parallel to the flat guide surfaces 18-25, so that the flat guide surfaces 18-25 slide against each other in pairs, i.e., 18, 23 and 19, 22 and 20, 24 and 21, 25. Simultaneously, the cylindrically convex guide surface 14 of the locking arm 10 slides on the cylindrically concave guide surface 16 of the locking arm 12. On the other side of the thread axis, the cylindrically concave guide surface 15 of the locking arm 11 of the first nut part 2 slides on the cylindrically convex guide surface 17 of the locking arm 13 of the second nut part 3.The locking arms 10-13 and the guide surfaces 14-25 guide the nut parts 2, 3 in a direction perpendicular to the parting plane of the nut parts 2, 3, which corresponds to the radial direction with respect to the thread axis. Simultaneously, the nut parts 2, 3 rotate relative to each other because their cylindrically curved guide surfaces 14-17 slide against each other until the stop surfaces 6 and 9 as well as 7 and 8 abut each other in the operating position.

[0053] In the operating position, the internal thread sections 4 and 5 complement each other to form a complete internal thread.

[0054] In the Fig. 1 and Fig. Figure 2 shows that the cylindrically curved guide surfaces 14-17 have retaining surfaces 27 near the free ends of the locking arms 10-13, which deviate slightly from the cylindrical contour of the guide surfaces 14-17. These retaining surfaces 27 form discontinuities which, when the nut parts 2, 3 are pushed together, lead to an elastic deformation of the locking arms 10-13. Therefore, when the nut parts 2, 3 are pushed together, resistance must be overcome as the retaining surfaces 27 slide past each other. These retaining surfaces 27 ensure that the inserted nut parts 2-3 are fixed to each other with a slightly opened internal thread. This position is shown in Fig. 5. This measure facilitates the handling of the nut parts 2, 3 when attaching them to an external thread. Furthermore, it is particularly important in Fig. 2. It can be seen that the concave guide surface 16 of the locking arm 12 has a detent bead 28 extending transversely to the guide surface 16 at a distance from its free end. The locking arm 10 of the nut part 2, which interacts with the locking arm 12, has a detent recess 29 at its free end. The detent bead 28 engages in the detent recess 29 when the nut parts 2, 3 are fully inserted into each other in the operating position, as shown in Fig. 6 to recognize.

[0055] At the first one, in the Fig. 1 and Fig. At the lower end of the internal thread, the nut parts 2, 3 have a shoulder surface 26 that projects annularly towards the axis of the internal thread. The shoulder surface 26 is located in the Fig. 1 and Fig. 2 is only recognizable on the first nut part 2 because it is concealed on the second nut part 3 by the locking arm 12. When the nut parts 2 and 3 are joined together, it forms a circumferential annular surface. It can be seen that the annular surface of the shoulder surface 26 is inclined conically to a radial plane of the internal thread, so that a complementary annular and conical support surface 36 ( Fig. 7) is engaged by the radial shoulder surface 26. The outer region of the radial shoulder surface 26, which has the greatest distance to the thread axis and borders the wall of the nut part 2 with the internal thread section 4, has a greater axial distance from the second, upper end of the internal thread section 4 than the inner region which lies near the thread axis. The shoulder surface 26 therefore extends in the Fig. 1 and Fig. 2 from its lowest point near the wall of the nut part 2 with the internal thread section 4 upwards on an inclined conical surface towards the thread axis. The inclination is 30° with respect to a plane that runs radially to the axis of the internal thread.

[0056] It should be noted that the surface of the shoulder surface 26 does not necessarily have to be a straight conical surface, but may be curved or have shoulders. What is important is that the shoulder surface 26 engages a complementary, radially outwardly shaped support surface 36 behind it (see Fig. 7).

[0057] The Fig. Figure 3 shows a representation of two components connected to each other by means of the screw nut from the Fig. 1 and Fig. 2 are to be connected. The first component is a plug 32, which has a head 37 and a slightly conical end section 33. The second component is a tube 31, the end of which is provided with an external thread 30. The conical end section 33 is to be inserted into the end of the tube 31 with axial pressure. The plug 32 has a substantially cylindrical shaft section 34, to which a radially projecting collar 35 adjoins. The surface of the collar 35 facing the head 37 of the plug 32 forms the support surface 36 for the shoulder surface 26 of the screw nut 1 (see Figure 2). Fig. 7) The support surface 36 is funnel-shaped, i.e. on a ring section of a conical surface inclined at about 30 degrees to the radial plane.

[0058] It should be noted that the components 31 and 32 to be connected are shown in the drawings only as examples. Other interlocking components can also be connected, e.g., two couplings of two fluid-conducting pipes or hoses.

[0059] The Fig. Figure 4 shows the plug 32 and the two nut parts 2, 3 from the Fig. 1 and Fig. 2. In this case, the mother part 2 is, compared to its position in the Fig. The nut part 1 is tilted by 90° and slightly rotated towards the viewer, so that its locking arms 10 and 11 point upwards. The nut part 3 is also tilted by approximately 90°, so that its locking arms 12 and 13 point downwards. Due to the division of the internal thread along the axial center plane, the nut parts 2 and 3 can be inserted into one another around the plug 32. In this position, the shoulder surface 26 of the nut lies opposite the support surface 36 of the collar 35 of the plug 32. During insertion, the nut parts 2 and 3 are guided against each other with their guide surfaces 14-25. Due to the retaining surfaces 27, the nut parts 2 and 3 lock together, although they are not yet fully inserted into one another. In this position of the nut parts 2 and 3, the external thread 30 can be inserted into the slightly opened internal thread of the nut parts 2 and 3, as shown in Fig. 5 is shown.

[0060] The nut parts 2, 3 can then be pushed into one another until the stop surfaces 6 - 9 are in contact with each other in the operating position and the internal thread formed by the nut parts 2, 3 surrounds the external thread 30 of the pipe 31 with minimal play (see Fig. 6 and Fig.7) In this operating position, the locking bead 28 and the locking recess 29 engage with each other in the guide surfaces 16, 14 of the locking arms 12, 10. The other locking arms 11, 13 may have corresponding locking bead 28 and locking grooves 29. By screwing the nut 1 onto the external thread 30, the shoulder surface 26 of the nut 1 is pressed against the support surface 36 of the collar 35 of the plug 32, and the plug 32 is pressed into the end of the tube 31. The compressive forces acting on the shoulder surface 26 of the two nut parts 2, 3 press the nut parts 2, 3 against each other and fix them together. Even if the screw connection loosens slightly, there is no risk of the two nut parts 2, 3 separating from each other, because due to the conical shape, the support surface 36 of the collar 35 engages behind the shoulder surface 26 of the screw nut 1.In this way, a firm and permanent connection is achieved using the nut 1. A thread-locking adhesive can be used to prevent this connection from loosening.

[0061] The union nut has been described in this description and in the drawings solely by reference to a two-part screw nut with cylindrically curved guide surfaces for generating the rotational movement when connecting and disconnecting the nut parts. However, it can also have differently designed guide surfaces, as described above and illustrated, for example, in EP 1 982 082 B1. The features of the invention disclosed in this description, in the drawings, and in the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of a person skilled in the art. Reference symbol list 1 screw nut 2 Mother part 3 Mother part 4 Internal thread section 5 Internal thread section 6 Stop surface 7 Stop surface 8 Stop surface 9 Stop surface 10 locking arm 11 Locking arm 12 Locking arm 13 Locking arm 14 curved guide surfaces 15 curved guide surfaces 16 curved guide surfaces 17 curved guide surfaces 18 flat guide surfaces 19 flat guide surfaces 20 flat guide surfaces 21 flat guide surface 22 flat guide surfaces 23 flat guide surfaces 24 flat guide surfaces 25 flat guide surfaces 26 Shoulder area 27 Holding surface 28 Rastwulst 29 rest area 30 external threads 31 pipe 32 plugs, first component 33 conical end section 34 shaft section 35 collars 36 support surface 37 heads

Claims

[1] Screw nut (1) with an internal thread and two nut parts (2, 3), wherein each of the nut parts (2, 3) has a section (4, 5) of the internal thread which can be slid onto an external thread (30) in a radial direction, and wherein the nut parts (2, 3) have interoperable connecting elements which allow a relative displacement of the nut parts (2, 3) in a direction radial to the axis of the internal thread to a position in use in which the internal thread of the screw nut (1) engages the external thread (30) with minimal play, wherein the connecting elements have guide surfaces (14 - 25) which guide the nut parts (2, 3) of the screw nut (1) in a rotational movement about an axis of rotation extending transversely to the axis of the internal thread when moving into the use position, wherein each nut part (2, 3) has at least one first locking arm (10, 13) which has a guide surface (14, 17) on one side which causes the rotational movement when the nut parts (2, 3) are moved and bears against a complementary guide surface (16, 15) on a second locking arm (12, 11) of the other nut part (3, 2), and wherein the screw nut (1) in the use position of the nut parts has a shoulder surface (26) extending towards the axis of the internal thread in the region of a first end of the internal thread, characterized by , that the shoulder surface (26) deviates from a plane extending radially to the axis of the internal thread and is such that the radially outer region of the shoulder surface (26) with the greatest distance to the axis of the internal thread has the greatest axial distance from the second end of the internal thread and the inner region of the shoulder surface (26) with the smallest distance to the axis of the internal thread has the smallest axial distance from the second end of the internal thread. [2] Screw nut (1) according to claim 1, characterized by , that the shoulder surface (26) is conically inclined. [3] Screw nut (1) according to claim 2, characterized by , that the average inclination of the shoulder surface (26) in an axial section plane is at least 30°. [4] Screw nut (1) according to any of the preceding claims, characterized by , that the shoulder surface (26) runs along a ring of a conical surface. [5] Screw nut (1) according to any of the preceding claims, characterized by , that the guide surface (14, 17) and the complementary guide surface (16, 15) comprise interoperating retaining elements which fix the nut parts (2, 3) to each other in a partially pushed-together position. [6] Screw nut (1) according to claim 5, characterized by , that the retaining elements are formed by retaining surfaces (27), which form discontinuities of the guide surfaces (14, 15, 16, 17). [7] Set comprising a screw nut (1) according to one of the preceding claims, characterized by, that it comprises a first component (32) with a shaft section (34) which can be encompassed by the compound screw nut (1), wherein an outwardly projecting support surface (36) for the shoulder surface (26) of the screw nut (1) adjoins the shaft section (34), which is inclined to the radial plane in accordance with the shoulder surface (26) of the screw nut (1) such that the shoulder surface (26) is coplanar to the support surface (36) in the compressed state of the screw nut (1) encompassing the shaft section (34).

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