SENSOR ASSEMBLY WITH FUSE FORMATION

Description

[0001] The present invention relates to a sensor assembly comprising at least three components formed separately from one another, namely a sensor housing extending along a sensor axis with a sensor accommodated therein, a sensor holder and a sensor carrier, wherein the sensor housing is held on the sensor carrier with the sensor holder interposed in a reference state of the sensor assembly ready for detection operation of the sensor, wherein the sensor holder has a tube section with an external thread which is in screw engagement with an internal thread of the sensor carrier along a screw axis, wherein the screw axis defines an axial direction running along the screw axis, radial directions running orthogonal to the screw axis and a circumferential direction running around the screw axis, wherein the tube section surrounds the sensor housing in the circumferential direction.

[0002] A sensor assembly with these features is known from JP 2008-224366 A and is used for mounting a sensor subject to high thermal stress in the exhaust system of a motor vehicle. To protect the screw engagement between the sensor mount and the exhaust pipe as the sensor carrier from seizing, at least the external thread of the sensor carrier is coated with an intermetallic iron-aluminum composite layer. This coating facilitates the removal of the sensor mount from the exhaust pipe after prolonged operation under pulsating thermal stress.

[0003] Such a sensor assembly is also used in the prior art, for example, to arrange a sensor in a container wall such that the sensor can detect as intended on one side of the container wall and that the sensor's detection signals can be tapped on the other side of the container wall. In this case, as in a preferred application of the present invention, the container wall forms the sensor carrier. In the case of the aforementioned JP 2008-224366 A, the exhaust pipe is the "container."

[0004] In the prior art, the sensor housing has an external sensor thread, by means of which the sensor housing is screwed into a corresponding internal thread of the sensor mount. The external sensor thread and consequently also the internal thread of the sensor mount are fine threads.

[0005] After completing the detection task, the sensor is removed from the sensor holder. Often, the container, which serves as the sensor carrier, and the sensor holder are intended for single-use only, for example, to avoid cross-contamination involving a medium collected in the container. The sensor, however, is more valuable and expensive than these disposable components and is reused. This is also possible because the sensor holder completely shields the sensor housing from the interior of the container.

[0006] While the sensor assembly can be easily disassembled by adhering to the specified assembly torques, especially by removing the sensor from the sensor mount screwed to the sensor carrier, users often fail to adhere to the specified torques, either because they do not have a suitable torque wrench on hand or because they underestimate the complexity of assembly and disassembly, which consists solely of screwing movements, and do not even bother to study the relevant instructions.

[0007] If specified assembly torques are not adhered to, indeterminate relative movements may occur during disassembly. Typically, a loosening torque is applied directly to the sensor housing, as this is usually the only housing accessible from outside the container. The sensor mount is typically screwed into the internal thread of the container wall from the inside of the container. A stop collar protruding radially outward from the sensor mount forms an end stop, which physically limits the screw-in depth of the sensor mount into the container wall.If, instead of the desired relative movement between the sensor housing and the sensor holder, an undesired relative movement occurs between the sensor holder and the sensor carrier because the sensor housing and sensor holder behave like a single component, the initiated screwing movement will release the sensor housing together with the sensor holder towards the interior of the container. The stop collar on the sensor housing prevents the sensor housing from being pulled out of the through-hole in the container wall that has the internal thread for receiving the sensor holder. To retrieve the sensor, either the sensor housing must be screwed back into the internal thread so that a new disassembly attempt can be made, or the interior of the container must be made accessible in order to separate the sensor holder from the sensor housing. The former involves considerably increased assembly work with uncertain success.The latter means a significantly increased risk of contamination in the area surrounding the container.

[0008] DE 20 2011 109 319 U1 discloses a screwable clamping device for the frictional securing of cylindrical components. An inner holding tube has, at its longitudinal end, leaf-spring-like threaded supports separated from one another in the circumferential direction by axially extending material weakenings. An external thread is formed on the radial outer side of the threaded supports, and their radially inward-facing surfaces are designed as clamping surfaces for engagement with the cylindrical component to be secured. By screwing a union nut with an internal thread onto the longitudinal end with the leaf-spring-like threaded supports, the leaf-spring-like threaded supports can be forced radially inward into frictional engagement with the cylindrical component arranged radially inside the holding tube.

[0009] For further technological background, please refer to the documents DE 10 2006 001 610 A, US 2016 / 003649 A1 and US 2012 / 255356 A1.

[0010] It is therefore an object of the present invention to improve the sensor assembly mentioned at the outset in such a way that the sensor housing can be safely assembled into an operational state and safely disassembled from an operational state as independently as possible of the tightening and / or loosening torques or assembly and / or disassembly forces to be observed.

[0011] The present invention achieves this object by a sensor assembly having the features of claim 1. The sensor assembly mentioned at the outset is further developed according to the invention in that at least one thread from the external thread of the sensor holder and the internal thread of the sensor carrier has a release-securing formation as a securing thread in at least one circumferential section of a thread groove, wherein the release-securing formation, based on a circumferential section of the thread groove free of the release-securing formation, reduces the cross-sectional area of the thread groove locally in the at least one circumferential section.

[0012] The term "locking thread" refers to the thread consisting of the external thread of the sensor holder and the internal thread of the sensor carrier, which has the release-locking formation.

[0013] In this application, "release-locking formation" refers to a formation on the locking thread that, by its function, secures a screw engagement between the external thread and the internal thread against loosening. The release-locking formation at least increases the torque required to release the screw engagement between the external thread and the internal thread, compared to a screw engagement of the same thread without the release-locking formation.

[0014] In technology, the term "thread" typically refers to the helical groove formed, depending on the thread type, on the outer circumference or inner circumference of a generally cylindrical or slightly conical surface for producing a screw engagement. Since individual sections of a thread must be distinguished from one another in this application, the helical groove of a thread is referred to in this application as a "thread groove." The thread groove is bounded axially, relative to the screw axis of a thread, on both sides by facing thread flanks. Thread flanks of axially immediately adjacent thread groove turns facing away from one another form a "thread projection" according to the terminology used in this application.An n-start thread therefore has exactly n thread grooves and n thread projections, where n is an integer and where a thread groove turn of a thread turn is formed between two axially immediately adjacent thread projection turns of the same thread turn and vice versa.

[0015] The opposing thread flanks of a thread groove are connected at one radial end by a groove base. The opposing thread flanks of a thread projection of the same thread are connected at the opposite radial end by a thread crest.

[0016] When creating a screw engagement between the external thread of the sensor mount and the internal thread of the sensor carrier, a complementary thread projection of the internal thread engages a thread groove of the external thread, and vice versa. "Complementary" does not necessarily mean that a thread projection of one thread completely fills the thread groove of the other thread into which it engages. This is not even desirable due to the large contact surfaces then existing between the thread projection and thread groove and the resulting high frictional torque that must be overcome. Rather, "complementary" should mean that the thread projection and thread groove are designed in such a way that a backlash-free screw engagement can be established and released between them.

[0017] By providing the release-locking formation on at least one of the threads mentioned, the engagement space for the complementary thread projection in the thread groove is reduced locally in the arrangement area of the release-locking formation, so that when the screw engagement is established in the arrangement area of the release-locking formation, a material displacement generally occurs, which has the effect of increasing the torque and thus brings about the desired release lock of the screw engagement once established.

[0018] Since a thread groove is open in a radial direction pointing away from its groove base with respect to its associated screw axis, it should be clarified that the cross-sectional area of a thread groove section is that area in a sectional plane containing the screw axis of the thread groove section in question, which is bounded in both opposite axial directions by the mutually facing thread flanks and in both opposite radial directions once by the groove base and once again by a virtual oscillating surface, in particular a virtual oscillating cylinder, on the thread crest sections running axially on both sides of the thread groove section. A virtual oscillating surface lies as a tangential surface touching a physical section without penetrating it.

[0019] Although it should not be ruled out in principle that both the external thread of the sensor holder and the internal thread of the sensor carrier may each have at least one release-locking formation, to facilitate the establishment of a screw engagement between the said threads, the formation of the at least one release-locking formation on only one of the said threads is preferred. The following description of the present invention assumes the preferred formation of the at least one release-locking formation on only one of the said threads.

[0020] The aforementioned material displacement to achieve the desired increase in the torque required to loosen the screw connection between the sensor mount and the sensor carrier can be due to various interactions between the release-locking formation and the thread complementary to the locking thread. These interactions can be divided into three basic categories: First, the complementary thread projection can displace material from the release-locking formation on the locking thread.

[0021] Second, the release-locking formation can displace material from the complementary thread projection. Third, a mutual displacement of both the release-locking formation and the complementary thread projection can occur.

[0022] In order to achieve the most defined material displacement possible, it is preferred if one formation consisting of the release-securing formation and a threaded projection section of the other thread consisting of the external thread of the sensor holder and the internal thread of the sensor carrier, which threaded projection section is in screw engagement with the securing thread and which threaded projection section is located in the circumferential extension area and in the axial extension area of the release-securing formation in the reference state of the sensor assembly, is harder and / or stiffer than the other formation. Hardness is the resistance to penetration into a surface of a material. Stiffness is the resistance to deformation, with resistance to compressive deformation, i.e. compressive stiffness, being of particular interest here. The compressive stiffness of a material is proportional to the material's modulus of elasticity. Its component stiffness depends on the shape of the component section.

[0023] Since, according to an advantageous development of the invention, this involves a container, such as a reactor vessel, in particular a bioreactor vessel, the sensor carrier is preferably made of steel, preferably stainless steel. The sensor carrier can be, for example, a fermentation container. The sensor carrier can be made of plastic, for example, preferably polycarbonate. The sensor holder is preferably an injection-molded component and thus predominantly or entirely made of thermoplastic.

[0024] If at least the thread projection portion of the complementary thread, preferably its entire thread projection, which in the reference state is arranged in the same circumferential and axial section as the release-securing formation, has a higher hardness and / or a higher rigidity than the release-securing formation, the thread projection of the complementary thread can displace material of the release-securing formation. Preferably, the thread projection of the complementary thread is tapered towards its thread crest, whereby a linear thread crest is preferred to achieve advantageously high wedge forces of the thread crest, so that the thread projection can cut into the material of the release-securing formation as a type of helical cutting edge. On the one hand, this advantageously leads to only moderately increased torques due to the pulling cut achieved during the screwing movement.On the other hand, the parts of the release-lock formation separated by the cut are in axial contact with the groove flanks of the thread projection on both sides with pressure and thus permanently increase the torque required to establish and release the screw engagement in both opposite directions of rotation.

[0025] If the release-locking formation is harder and / or stiffer than the thread projection section, the release-locking formation can press a recess into the thread projection of the complementary thread. For this purpose, it is advantageous if the release-locking formation forms at least one edge running transversely to the thread crest of the thread projection of the complementary thread. This edge can also act like a cutting edge, cutting or pressing into the thread projection from the thread crest of the thread projection of the complementary thread. As a rule, the release-locking formation physically penetrates the notch, or generally recess, created by material displacement in the thread projection and thus ensures a positive engagement with the thread projection of the complementary thread, which inhibits or at least complicates a loosening screw movement of the locking thread relative to the complementary thread.

[0026] If the groove flanks of the thread projection of the complementary thread form a small wedge angle and, at the same time, the release-locking formation has a stable edge that runs transversely to the thread crest of the complementary thread in the extension area of the release-locking formation, with the boundary surfaces of the release-locking formation bordering the edge on both sides enclosing a larger wedge angle than the thread projection, the release-locking formation can press a recess from the thread crest into the thread projection even if the thread projection of the complementary thread is made of a harder and / or stiffer material than the release-locking formation. The shapes of the interacting formations: release-locking formation and thread projection, can then, within certain limits, be more decisive than the respective material.This may then result in mutual deformation and material displacement. However, the advantage is that by pressing a notch into the threaded projection and at least partially retaining the release-locking formation in the notch itself, an effective, positive-locking release lock of the sensor mount on the sensor carrier is achieved.

[0027] Since the force ratios at the displacement location change during the course of material displacement, for example because the forces and torques required for further displacement increase significantly with the increasing amount of displaced material, a mixed form of the two deformations mentioned above can occur when screwing the locking thread with the complementary thread, so that both the release-locking formation and the thread projection of the complementary thread are deformed.

[0028] Firstly, as described above, the release-locking formation itself can be deformed. However, if release-locking is to be achieved primarily by deforming the thread projection of the complementary thread, a material weakening can be formed in a weakened area of the sensor holder to ensure that the release-locking formation initially remains undeformed for as long as possible during the production of the screw connection. Since the release-locking formation generally comes into contact with the thread projection of the complementary thread during the production of the screw connection due to the resulting reduction in the cross-sectional area of the thread groove containing it, it is advantageous if the material weakening is formed in the area of the external thread.The weakened area, which is preferably considered for the formation of the material weakening, therefore preferably contains the entire external thread and extends axially, with respect to a screw axis of the external thread, on both sides of the external thread beyond the external thread by at least twice the thread pitch of the external thread. If the material weakening is formed in this weakened area, the rigidity of the pipe section carrying the external thread can be reduced, so that contact between the release-locking formation and the thread projection can initially cause an evasive deformation of the pipe section in the radial direction towards the virtual screw axis. In this way, premature deformation of the thread projection by the release-locking formation during the establishment of the screw engagement and thus an undesirable increase in the torque required to establish the screw engagement can be prevented.

[0029] According to a preferred structural embodiment of the sensor holder, the material weakening can comprise a concave depression formed in a surface of the sensor holder, which extends in the thickness direction from the surface into the sensor holder. The material weakening has a width measured in a width direction orthogonal to the thickness direction, the material weakening having its largest dimension along a direction orthogonal to both the thickness direction and the width direction. The material weakening can be formed on the inner side of the pipe section or sensor holder opposite the external thread, but is preferably formed on the outer side of the pipe section bearing the external thread.

[0030] In principle, to reduce the radial component stiffness of the pipe section or the sensor mount, i.e., to reduce the resistance to radial deformation under a given radial load, it may be sufficient if the material weakening forms only a local thin spot in the pipe section or the sensor mount. A particularly large local reduction in radial component stiffness can be achieved by having the material weakening penetrate the sensor mount in the thickness direction.Even if the material weakening can be designed as a perforation in which sections penetrating the pipe section in the thickness direction alternate with non-penetrating sections in the direction of the material weakening, the design of the material weakening as a groove running continuously in the direction of the material weakening and penetrating the pipe section in the thickness direction is preferred because of the associated considerable local reduction in the radial component stiffness.

[0031] To provide sufficient residual component rigidity of the sensor mount and in particular its tube section, the sensor mount and in particular the tube section preferably comprise a component section that runs completely around the circumference on both sides of the material weakening. These component sections are free of the material weakening located axially between them.

[0032] The direction of the material weakening can have an axial component with respect to the screw axis of the external thread. It can even have an exclusively axial component, so that through interaction of the release-securing formation with the thread projection of the complementary thread, one of two circumferentially opposite edges of a purely axially extending material weakening can be displaced radially inward toward the screw axis relative to the other edge. In order to ensure that the release-securing formation causes a displacement of a region of the pipe section when establishing the screw engagement with the sensor carrier, according to a development of the present invention, the at least one release-securing formation is arranged in the axial extension region of the material weakening in the reference state of the sensor assembly.

[0033] Additionally or preferably alternatively, the direction of extension of the material weakening can have a component in the circumferential direction with respect to the screw axis of the external thread. Again, the direction of extension can only run in the circumferential direction, so that through interaction of the release-securing formation with the thread projection of the complementary thread, one of two axially opposite edges of a material weakening running purely in the circumferential direction can be displaced radially inward towards the screw axis relative to the other edge. For the reasons already stated in the previous paragraph, the at least one release-securing formation is preferably arranged in the circumferential extension region of the material weakening in the reference state of the sensor assembly in order to be able to bring about the greatest possible relative movement of the two regions of the sensor holder located on either side of the material weakening.

[0034] To enable the described radial displacement of a portion of the pipe section when screwing the sensor mount into the sensor, the sensor housing is preferably only inserted into the pipe section of the sensor mount once the screw engagement between the sensor mount and the sensor carrier has been established. The radially inwardly displaced portion of the pipe section can then be pushed back radially outward by the sensor housing, i.e., away from the virtual screw axis.

[0035] In principle, the release-preventing formation can be formed on the internal thread or on the inner wall of the sensor carrier supporting the internal thread. Then, according to the aforementioned advantageous development of the present invention, the release-preventing formation should be arranged in that axial region and / or circumferential region of the internal thread or the inner wall in which the material weakening of the sensor holder is arranged in the reference state. The sensor holder and / or the sensor carrier can have an end stop which limits the axial relative movement of the sensor holder when screwed into the sensor carrier. The end stop is preferably formed as a radial projection, particularly preferably as a radial projection running circumferentially, on the sensor holder.With the same screw-in depth and when using the same components, i.e., the sensor holder on the one hand and the sensor carrier on the other, the material weakening relative to the screw-in start of at least one thread of the internal thread of the sensor carrier in the reference state always lies in the same axial and / or circumferential area. By arranging the release-lock formation axially and / or circumferentially relative to the screw-in start of one of the threads involved in the screw engagement, the desired arrangement of the release-lock formation relative to the material weakening in the reference state can be ensured.Since the sensor holder is usually always screwed into the sensor carrier from the same side and with the same relative orientation relative to the sensor carrier, it is clear on both the external thread of the sensor holder and the internal thread of the sensor carrier which longitudinal end of a thread is the screw-in start and which opposite longitudinal end is the screw-in end. When the screw engagement begins, the two screw-in starts of the involved threads are brought into screw engagement, and then each screw-in start is moved towards the screw-in end of the other thread by screwing.

[0036] Preferably, the release-securing formation is formed directly on the sensor holder carrying the material weakening, which considerably facilitates the achievement of the desired relative position of the release-securing formation and the material weakening.

[0037] Although, as explained above, a material weakening running purely axially or purely in the circumferential direction may already be sufficient, a much more significant and at the same time specifically adjustable reduction in the radial stiffness of the pipe section or of the sensor holder can be obtained by changing the direction of extension of the material weakening formed contiguously in the direction of extension along its extension, so that the material weakening encloses a deformation region of the sensor holder, wherein the at least one release-securing formation is arranged in the deformation region.The deformation area can thus be displaced radially inward towards the virtual screw axis as a bending deformation area relative to the remaining tube section of the sensor holder by interaction of the release-locking formation with the thread projection of the complementary thread due to the reduction of the thread groove cross section of the locking thread caused in the arrangement area of the release-locking formation when establishing the screw engagement between the sensor holder and the sensor carrier.

[0038] In principle, the sensor axis can be inclined relative to the screw axis in the reference state. To achieve a radially slender structure consisting of the sensor housing and sensor mount, the sensor axis is at least parallel, preferably coaxial, to the screw axis in the reference state.

[0039] In principle, the release-locking formation can reduce the cross-sectional area of the thread groove of the locking thread in any way by protruding into the thread groove. An advantageously stable release-locking formation with sufficiently predictable behavior during the establishment of the screw engagement can be achieved by having the release-locking formation in the thread groove of the locking thread, over a predetermined circumferential extent, a smaller thread groove depth compared to a thread groove section free of a release-locking formation.

[0040] The release-securing formation can be subsequently applied to an already produced thread groove, which allows the release-securing formation to be made of a material that is different from the material of the securing thread. For example, the securing thread can be formed of metal, in whose thread groove a collection of plastic, in particular thermoplastic, can be applied as a release-securing formation. For reasons of ease of manufacture, the release-securing formation is preferably made of the same material and integrally formed with the securing thread. As the disposable component, which is usually the sensor holder that preferably carries both the material weakening and the release-securing formation, at least the tube section is designed as an injection-molded component.The injection-molded component can be manufactured by injection molding with the locking thread and with at least one release-lock formation in a simple, cost-effective and repeatable manner.

[0041] Since the release-securing formation is intended to at least make it more difficult to release the screw engagement, but preferably not to establish it, the release-securing formation can be designed such that it acts as a type of starting bevel when establishing the screw engagement. For this purpose, in a specific structural embodiment, the release-securing formation can have a cross-sectional reduction section in which the thread groove depth in the circumferential extension area along the thread groove profile decreases gradually and / or continuously in a screwing-in direction in the direction from a screw-in start to a screw-in end of the securing thread with respect to a screwing-in process of the sensor holder into the sensor carrier. The cross-sectional reduction section can protrude radially from the groove, i.e., project radially beyond the thread crest beyond a reduction of the thread groove depth to zero.In the case of a gradual decrease in the thread groove depth, an edge as already mentioned above can be formed at each step end of the release-locking formation following in a screwing direction, extending transversely to the course of the thread groove of the locking thread at the location of the release-locking formation.

[0042] The edge running transversely to the course of the thread groove of the securing thread at the formation location of the release-securing formation, which edge is designed to deform the thread crest of the complementary thread, can be realized in that the release-securing formation has a cross-sectional enlargement section following the cross-sectional reduction section in the direction from the screw-in start to the screw-in end, in which the thread groove depth increases stepwise and / or continuously in the circumferential extension area along the thread groove course in the direction from the screw-in start to the screw-in end.

[0043] To achieve the reduction in cross-sectional area, the release-securing formation can have an interface which runs axially with respect to the screw axis of the securing thread between thread flanks that delimit the thread groove, wherein the radial distance of the interface from the screw axis changes along the circumferential extent of the interface. This interface preferably borders axially on both sides of the groove flanks delimiting the thread groove and thus extends axially from groove flank to groove flank. This results in an advantageously rigid release-securing formation. The interface can be flat or, when viewed radially towards the thread groove, can be concavely curved around an axis of curvature tangential to the thread groove. As a result, the interface has a neutral effect upon contact with a thread crest of the complementary thread or axially centers the thread crest with respect to the thread groove.Alternatively or additionally, the interface may be convexly curved around a curvature axis parallel to the screw axis.

[0044] To form the aforementioned edge, which, after the screw engagement has been established, deforms the thread projection of the complementary thread from the thread crest, in particular forming a notch, the interface can form a crest region in which the cross-sectional area of the thread groove along the circumferential extension area of the release-securing formation is minimal. The shorter the crest region in the circumferential direction, the higher the local surface pressures achievable in the crest region, which ultimately cause the deformation of the thread projection. Therefore, although the crest region can form a crest surface, a purely linear crest region extending transversely to the thread groove section in which the crest region is located is preferred.

[0045] The boundary surface can end in the circumferential direction directly at the material weakening. The material weakening can then enable a radially sloping flank of the release-locking formation, which has a larger radial dimension than the thread groove containing the release-locking formation. Consequently, the release-locking formation can not only form a pronounced pointed edge with a course transverse to the course of the thread groove section that supports it, but can also provide a particularly deep radial deformation path into the thread projection of the complementary thread. The release-locking formation can thus, for example, have a sawtooth shape, the trailing sloping flank of which in the screwing direction has a greater radial extent than the leading rising flank.

[0046] In order to exert a sufficient deformation force to deform an area adjacent to the material weakening in the sensor holder, in particular the above-mentioned deformation area, the sensor assembly can have a plurality of release-securing formations which are arranged one behind the other in a thread turn.

[0047] The release-locking formations arranged one behind the other preferably cause a different reduction in the cross-sectional area of the threaded groove, so that, for example, a first release-locking formation engaging during screwing causes a smaller amount of pre-deformation of a region of the pipe section or sensor holder weakened by the material weakening, and so that at least one subsequently engaging release-locking formation causes a larger amount of deformation. Preferably, the reduction in the cross-sectional area of the threaded groove caused by individual release-locking formations increases across the plurality of release-locking formations arranged one behind the other and acting on the same circumferential region of the sensor holder, i.e., the cross-sectional area itself decreases in the arrangement regions of the release-locking formations.

[0048] Preferably, the plurality of release-securing formations are arranged in the deformation region in order to displace the deformation region as effectively and safely as possible when screwing the sensor holder into the sensor carrier.

[0049] With the aim of deforming the deformation region as effectively and safely as possible, the release-securing formation or, in the case of a plurality of release-securing formations with different cross-sectional reductions, the release-securing formation with the greatest cross-sectional reduction is preferably arranged in that thread groove section of the deformation region which, within the deformation region, has the greatest distance from a shortest virtual connecting line, wherein the virtual connecting line connects the two ends of the material weakening enclosing the deformation region at a constant radial distance from the screw axis of the locking thread. The described shortest virtual connecting line between the end regions of the material weakening is essentially the bending axis around which the deformation region enclosed by the material weakening is deflected in a bending manner when the screw engagement is established.The greater the distance from the bending axis, the lower the force required for a given deflection.

[0050] The inner recess of the sensor holder is preferably formed with such a small gap relative to the sensor housing that a radial displacement of a region weakened by the material weakening, in particular the deformation region, by interaction of the at least one release-securing formation with the thread projection of the complementary thread, reduces the clear width of the inner recess to a dimension which is smaller than a corresponding outer dimension of the section of the sensor housing inserted into the inner recess of the sensor holder which section axially overlaps the weakened region, in particular the deformation region, in the reference state.As a result, when inserting the sensor housing into the sensor holder, the section of the sensor holder displaced radially inward by the at least one release-locking formation can be pushed back radially outward, whereby an edge formed by the release-locking formation penetrates and deforms the radially opposite thread projection of the complementary thread and / or the thread projection penetrates the release-locking formation. The sensor housing blocks a renewed radial movement of the section of the sensor holder pushed radially outward by the sensor housing back radially inward toward the virtual screw axis.As a result, the sensor housing not only pushes the release-locking formation into the threaded projection and / or vice versa, deforming it, but also holds the release-locking formation and the threaded projection in the engagement position thus created and thus ensures a force and / or form-locking engagement between the release-locking formation and the threaded projection created by the described deformation.

[0051] Due to the area weakened by the material weakening, in particular the deformation area, the sensor housing can be clamped in the sensor holder in the reference state only by frictional engagement. Alternatively or in addition to clamping the sensor housing in the sensor holder, in particular in the pipe section, the sensor housing can have a securing formation which can be brought into securing engagement with a securing counter-formation in an inner recess of the sensor housing, in particular on its pipe section. One formation consisting of the securing formation and the securing counter-formation can be a radial projection, and the other formation can be a groove receiving the radial projection, which, as a bayonet lock, has an axial section running predominantly or exclusively in the axial direction and an adjoining circumferential section running in the circumferential direction.Alternatively, the securing formation can comprise an external thread and the securing counter-formation can comprise a complementary internal thread, preferably a fine pitch thread, as is already known from the prior art. By means of a securing formation cooperating with a securing counter-formation, the sensor housing can be arranged in a spatially defined manner and secured against displacement relative to the sensor mount.

[0052] In order to minimize interference between the engagement of the securing formation and the securing counter-formation, the securing counter-formation is preferably formed or arranged axially outside the arrangement region of the material weakening, in particular the deformation region. Preferably, the securing counter-formation is arranged at least partially in front of the material weakening, in particular the deformation region, in the insertion direction of the sensor housing into the sensor holder, so that a housing section located closer to the insertion longitudinal end of the sensor housing than the securing formation pushes the weakened region of the sensor holder radially outwards. This prevents the securing formation from having to be moved past the weakened and generally radially inwardly displaced region of the sensor holder.

[0053] A sensor holder comprises a tube section with an external thread formed on the tube section, wherein the external thread has a release-locking formation as a securing thread in at least one circumferential section of a thread groove. The release-locking formation reduces the cross-sectional area of the thread groove relative to a circumferential section of the thread groove free of a release-locking formation. A material weakening is formed in a weakened region of the sensor holder, wherein the weakened region contains the entire external thread and extends axially, relative to a screw axis of the external thread, on both sides of the external thread beyond the external thread by at least twice the thread pitch of the external thread.A direction of extension of the material weakening, in which the material weakening has its largest dimension, has an axial component and / or a component in the circumferential direction with respect to the screw axis of the external thread, wherein the at least one release-securing formation is arranged in the axial extension region of the material weakening and / or is arranged in the circumferential extension region of the material weakening.

[0054] What was said above about the sensor mount in the description of the sensor assembly naturally also applies to the sensor mount alone and vice versa.

[0055] The sensor mount can have more than one material weakening, with the material weakenings being offset from one another in the circumferential direction around the screw axis in order to create the largest possible number of regions of the sensor mount that are easier to deform radially. The sensor mount can therefore have more than one deformation region, with the deformation regions then being offset from one another in the circumferential direction around the screw axis.

[0056] If the sensor holder has more than one material weakening, in particular more than one deformation region, preferably each material weakening, in particular each deformation region, is assigned at least one release securing formation which is arranged or formed in the axial extension region and / or in the circumferential extension region of the respective material weakening and / or in the extension region of the respective deformation region.

[0057] The present invention will be described in more detail below with reference to the accompanying drawings. It shows: Figure 1 is an elevation view of an embodiment of a sensor holder according to the invention of the present application, Figure 2 is a perspective view of the sensor holder of Figure 1 , Figure 3 an enlarged view of the external thread with material weakening and release-lock formation of the sensor holder of the Figures 1 and 2 , Figure 4 a sectional view of a section of a sensor carrier of an inventive embodiment of a sensor assembly of the present application, Figure 5 a longitudinal sectional view of a detection and insertion area of a sensor housing with sensor of an inventive embodiment of a sensor assembly of the present application, Figure 6 the sensor carrier of Figure 3 with the sensor holder screwed into it Figures 1 and 2, and Figure 7 shows a sensor assembly of the present application, comprising the sensor carrier with the sensor holder screwed into it from Figure 5 with the sensor housing inserted into the sensor holder according to Figure 4 .

[0058] In the Figures 1 to 3 An embodiment of a sensor holder according to the invention of the present application is generally designated 10. The sensor holder 10 extends along a screw axis S. The sensor holder 10 comprises a hollow, cylindrical tube section 12 in the illustrated embodiment, and a base 14 closing the tube section 12 on one side.

[0059] From its longitudinal end 16 axially opposite the base 14 with respect to the screw axis S, the sensor holder 10 or the pipe section 12 is open, so that a Figure 4shown sensor housing 18 can be inserted with its insertion longitudinal end 20 leading into the pipe section 12 along the screw axis S in the axial direction A.

[0060] The screw axis S defines the axial direction A, radial directions R orthogonal to the screw axis S and a circumferential direction U circulating around the screw axis S.

[0061] The pipe section 12 has an external thread 22, which in the example shown is single-start. The external thread 22 has a thread groove 22a, with axially immediately adjacent turns of the thread groove 22a forming a thread projection 22b separating the turns from one another.

[0062] As shown on the contour line of the external thread 22 in Figure 1 As can be seen, the thread groove 22a is axially delimited by groove flanks 24a and 24b facing each other. Accordingly, the thread projection 22b is delimited by groove flanks 24b and 24a facing away from each other.

[0063] The thread groove 22a is delimited radially inward by a groove base 26. The thread groove 22a is open radially outward, as is typical for threads. The thread projection 22b is delimited radially outward by a thread crest 28.

[0064] The external thread 22 is formed on a cylindrical section of the pipe section 12 or the sensor holder 10 and thus has a virtual cylindrical locating surface 30, which bears against the thread crest 28. The locating surface 30, whose cylinder axis is coaxial with the screw axis S, is in Figure 1 merely indicated by dashed lines. Between the contour line of the external thread 22 and the skewed surface 30, the cross-sectional area Q of the thread groove 22a is visible as a hatched area in a thread groove section free of release-locking formations, which will be explained in more detail below. It has a roughly V-shaped configuration. Figure 1The recognizable contour line lies in a plane containing the screw axis S and to the drawing plane of the Figure 1 parallel plane.

[0065] The external thread 22 is threaded from its longitudinal end 16 into an internal thread 32 of a Figure 4 screwed into the sensor carrier 34, which is partially shown in isolation. The end of the external thread 22 closer to the longitudinal end 16 is therefore its screw-in start 36. The opposite end of the external thread 22 is its screw-in end 38. The screw-in start of the internal thread is in Figure 4 with 37, the screw-in end with 39. The sensor carrier 34 can be part, in particular an integral component, of a container wall, such as a reactor container or bio-reactor container.

[0066] In the example shown, the pipe section 12 has, approximately in its longitudinal center, a radial projection 40 which runs completely around the circumference in the circumferential direction, the contact surface 40a of which, orthogonal to the screw axis S, comes into contact with a boundary surface 34a of the sensor carrier 34 as a physical end stop of the sensor holder 10 in the screwed-in state of the sensor holder 10 in a ready-to-use state.

[0067] A hexagonal tool engagement formation 42 is formed on an axial section of the radial projection 40 further away from the external thread 22, so that the sensor holder 10 can be screwed into the internal thread 32 of the sensor carrier 34 using a wrench with a conventional wrench size. A projection section 44, which adjoins axially on the side of the radial projection 40 facing away from the external thread 22, projects axially from the boundary surface 34a of the sensor carrier 34 in addition to the radial projection 40 in the fully assembled, operational state of the sensor holder 10.

[0068] An axial region of the pipe section 12, which includes the entire external thread 22 and, axially on both sides, a pipe section length of approximately two additional thread pitches of the external thread 22, is provided as a weakened region 46. In this weakened region 46, a material weakening 48 is formed as a groove extending through the pipe section 12 in the thickness direction. The material weakening 48 has an axial leg 48a and a leg 48b extending in the circumferential direction.

[0069] A virtual connecting line 50, which connects the longitudinal ends of the material weakening 48, forms a bending axis of a deformation region 52 enclosed by the material weakening 48. In the example shown, the deformation region 52 is triangular, although this shape is chosen merely as an example. The tip 54 of the triangular deformation region 52 is at the greatest distance from the virtual connecting line 50, which acts as the bending axis, and is thus radially deflectable to the greatest extent relative to its undeformed initial shape under a given radial load.

[0070] Through the axial leg 48a, a fine thread can be seen on the inside of the pipe section 12 as an internal thread 56, into which the sensor housing 18 can be screwed with its external thread 58 formed on the outer circumference in order to fix the sensor housing 18 to the sensor holder 10.

[0071] Through the circumferential leg 48b, a further material weakening of the same shape is visible diametrically opposite. The further material weakening corresponds to the Figure 1 material weakening 48 facing the viewer, rotated by 180° around the screw axis S.

[0072] While the material weakening 48 can be arranged at any location within the weakening area 46, it is preferably arranged in the extension area of the external thread 22.

[0073] In the deformation area 52, in the example shown, a total of three release-securing formations 60a, 60b and 60c are formed, which for the sake of clarity are shown below in conjunction with the enlarged illustration of Figure 3 be explained.

[0074] Using the example of the largest and therefore most clearly recognizable release-safety formation 60c, Figure 3recognize that this is a material accumulation in the thread groove 22a, wherein the release-securing formation 60c has a boundary surface 62 pointing towards the screw-in start 36, which in the example shown is flat, parallel to the screw axis S and inclined with respect to the course of the thread groove 22a in the section having the release-securing formation 60c. The circumferential extension area of the boundary surface 62 thus forms a cross-sectional reduction section 63, along which the cross-sectional area Q decreases continuously in a screw-in direction from the screw-in start 36 to the screw-in end 38. The accumulation of material fills the thread groove 22a radially outward from the groove base 26, so that the boundary surface 62 extends to the groove base 26 or to the mutually facing groove flanks 24a and 24b, which delimit the section of the thread groove 22a in which the release-securing formation 60c is formed.

[0075] At its radially outer end, the release-securing formation 60c forms a crest 64 in the form of an edge 66. The edge 66 extends transversely to the direction of the thread groove section having the release-securing formation 60c. Thus, the edge 66 also extends transversely to a thread projection 32a of the complementary internal thread 32 of the sensor carrier 34, which engages in the thread groove 22a when the screw engagement is established. Starting from the longitudinal end of the interface 62 leading in the screwing direction in the circumferential direction U up to the crest 64 of the interface 62, the thread groove depth in the cross-sectional reduction section 63 decreases continuously.

[0076] The edge 66 forms part of the edge of the axial leg 48a of the material weakening 48. A flank of the release-locking formation 60c, not visible in the figures, which points away from the screw-in beginning, i.e., trails in the screw-in direction, forms a peripheral edge surface of the axial leg 48a. The trailing flank of the release-locking formation 60c thus extends over the entire radial thickness of the pipe section 12 in the region of the external thread 22.

[0077] The edge 66 also runs between axially adjacent turns of the thread crest 28. As a result, the release-securing formation 60c completely fills the thread groove 22a in the region of its crest 64 and reduces its cross-sectional area Q in the region of the crest 64 or the edge 66 to 0.

[0078] For the release-locking formations 60b and 60a located closer to the screw-in start 36, what has been said for the release-locking formation 60c applies accordingly, but with the proviso that their vertices, which are designed as edges, are located radially closer to the screw axis S, so that the release-locking formations 60b and 60a do not completely fill the thread groove 22a and thus reduce their cross-sectional area Q less than the release-locking formation 60c, whereby the reduction in the cross-sectional area Q is less pronounced the closer the respective release-locking formation is to the screw-in start 36.

[0079] When the sensor holder 10 is screwed into the internal thread 32 of the sensor carrier 34, the release-locking formations 60a, 60b, and 60c successively engage the threaded projection 32a of the complementary internal thread 32. Due to the material weakening 48, this engagement causes the deformation region 52 to bend radially inward around the virtual connecting line 50 as the bending axis, with the point 54 of the deformation region 52 furthest from the virtual connecting line 50 being deflected the most. To support this greatest deflection of point 54, the release-locking formation 60c, which tapers the cross-sectional area Q of the thread groove 22a the most, is located closest to point 54 of the three existing release-locking formations 60a, 60b, and 60c.

[0080] A longitudinal section through the sensor carrier 34 with the sensor holder 10 screwed into its internal thread 32, but still without the sensor housing 18, is shown in Figure 6 shown. There it is clearly visible how the deformation area 52 is deformed radially inwardly towards the screw axis S due to the contact engagement between the release-securing formations 60a, 60b and 60c with the thread projection 32a of the complementary internal thread 32. This applies to both deformation areas 52 formed on the sensor holder 10, whereby due to the position of the cutting plane of Figure 6 the relocation of the Figure 6 right deformation area 52 is shown more pronounced.

[0081] The sensor holder 10 is sealed from the sensor carrier 34 by an O-ring seal 67.

[0082] The sensor holder 10 is designed to hold the Figure 5The sensor housing 18 is formed as shown. The sensor housing 18 extends along a sensor axis P, with a sensor 68 being arranged in the region of the insertion longitudinal end 20, for example an optical sensor operating according to the principle of luminescence quenching for determining the oxygen content of a medium contained in the container, of which the sensor carrier 34 is a part. To ensure that the medium whose oxygen content is to be determined reaches the luminophore of the sensor 68, an opening 72 covered by an oxygen-permeable, but preferably liquid-impermeable and / or, if necessary, vapor-impermeable membrane 70 is formed in the base 14 of the sensor holder.

[0083] The sensor housing 18 with the sensor 68 in Figure 5 is shown only roughly schematically. With the exception of the design of the fine thread 58, at least in the Figure 4shown area is composed of coaxial cylindrical sections, each of which has the sensor axis P as the cylinder axis.

[0084] A through-opening 74 of the sensor carrier 34, in which the internal thread 32 is designed for screw engagement with the external thread 22, completely penetrates the sensor carrier 34.

[0085] The sensor holder 10 and the sensor housing 18 are inserted from opposite sides into the through-opening 74 of the sensor carrier 34. Starting from the Figure 6 In the state shown of a screw engagement between only the sensor holder 10 and the sensor carrier 34, the sensor housing 18 with the sensor axis P coaxial to the screw axis S is inserted from the outside of the sensor carrier 34 into the through opening 74 and into the sensor holder 10 screwed into the sensor carrier 34.

[0086] The clear width of the inner recess 76 of the sensor holder 10 is, in the undeformed state of the sensor holder 10, only slightly larger than the outer diameter of the sensor section 78 inserted into the sensor holder 10.

[0087] Then, when the deformation region 52 is deformed radially inwardly towards the screw axis S in the manner described above, the clear width of the inner recess 76 in the extension region of the deformation region 52 is smaller than the outer diameter of the sensor housing 18, so that when the sensor housing 18 is inserted into the sensor holder 10, the deformation region 52 displaced radially inwardly by the release-securing formations 60a, 60b, 60c is physically pushed radially outwardly by the sensor housing 18 in the direction away from the screw axis S.

[0088] As a result, the edges 66 of the release-securing formations 60a, 60b and 60c are forced into the threaded projection 32a of the complementary internal thread 32, where they themselves, as injection-molded component sections, penetrate at least a little way into the threaded projection 32a by displacing the thread crest of the threaded projection 32a and form a recess 80 in the form of a notch. This situation is in Figure 7 , which shows a sensor assembly 82 with the components sensor housing 18, sensor holder 10, and sensor carrier 34. Since the sensor housing 18 inserted into the sensor holder 10 forms a physical blockage of the deformation areas 52, the release-lock formations 60a, 60b, and 60c remain in the recesses 80 they themselves create in the threaded projection 32a and thus prevent the sensor holder 10 from being unscrewed from the sensor carrier 34.

[0089] Thus, when the sensor housing 18 is unscrewed from the sensor holder 10, a torque in a release direction is exerted on the only accessible longitudinal end of the sensor housing 18, which is remote from the sensor 68. Due to the friction that inevitably occurs between the components involved: sensor housing 18, sensor holder 10, and sensor carrier 34, a torque in a release direction is also exerted on the sensor holder 10 relative to the sensor carrier 34. The release torque transmitted to the sensor holder 10 via frictional engagement cannot overcome the positive engagement between the radially outwardly pushed release-securing formations 60a, 60b, and 60c and the threaded projection 32a, so that the sensor housing 18 can be safely removed from the sensor holder 10 after use.

Claims

1. A Sensor assembly (82), comprising at least three components formed separately from one another, namely a sensor housing (18) extending along a sensor axis (P) with a sensor (68) accommodated therein, a sensor bracket (10) and a sensor carrier (34), the sensor housing (18), in a reference state of the sensor assembly (82) ready for a detection operation of the sensor (68), being held on the sensor carrier (34) with the sensor bracket (10) being arranged in between, the sensor bracket (10) having a pipe section (12) with an external thread (22) which is in screw engagement with an internal thread (32) of the sensor carrier (34) along a screw axis (S), the screw axis (S) defining an axial direction (A) running along the screw axis (S), radial directions (R) extending orthogonally to the screw axis (S) and a circumferential direction (U) extending around the screw axis (S), wherein the pipe section (12) surrounds the sensor housing (18) in the circumferential direction (U), characterized in that at least one thread (22) of the external thread (22) of the sensor bracket (10) and the internal thread (32) of the sensor carrier (34) as a locking thread (22) has a release-locking formation (60a, 60b, 60c), wherein the release-locking formation (60a, 60b, 60c), in relation to a circumferential section of the thread groove (22a) which is free from the release-locking formation (60a, 60b, 60c), reduces the cross-sectional area (Q) of the thread groove (22a) locally in the at least one circumferential section.

2. Sensor assembly (82) according to claim 1, characterized in that one formation of a.) the release-locking formation (60a, 60b, 60c) and b.) a thread projection section, which in the reference state of the sensor assembly (82) is located in the circumferential extension region and in the axial extension region of the release-locking formation (60a, 60b, 60c), of the other thread of the external thread (22) of the sensor bracket (10) and internal thread (32) of the sensor carrier (34), which thread is in screwing engagement with the locking thread (22), is harder or / and stiffer than the respective other formation.

3. Sensor assembly (82) according to claim 1 or 2, characterized in that a material weakening (48) is formed in a weakening region (46) of the sensor bracket (10), the weakening region (46) containing the entire external thread (22) and extending axially, in relation to a screw axis (S) of the external thread (22), at least twice the thread pitch of the external thread (22) over the external thread (22) on both sides of the external thread (22).

4. Sensor assembly (82) according to claim 3, characterized in that the material weakening (48) comprises a concave depression formed in a surface of the sensor bracket (10), which depression extends in the thickness direction starting from the surface into the sensor bracket (10), the material weakening (48) having a width to be measured in a width direction orthogonal to the thickness direction, the material weakening (48) having its largest dimension along a direction of extension orthogonal to both the thickness direction and the width direction.

5. Sensor assembly (82) according to claim 4, characterized in that the material weakening (48) passes through the sensor bracket (10) in the thickness direction.

6. Sensor assembly (82) according to claim 4 or 5, characterized in that the direction of extension of the material weakening (48) has an axial component (48a) with respect to the screw axis (S) of the external thread (22), the at least one release-locking formation (60a, 60b, 60c), in the reference state of the sensor assembly (82), being arranged in the axial extension region of the material weakening (48) or / and the direction of extension of the material weakening (48), with respect to the screw axis (S) of the external thread (22), having a component (48b) in the circumferential direction (U), wherein the at least one release-locking formation (60a, 60b, 60c), in the reference state of the sensor assembly (10), is arranged in the circumferential extension region of the material weakening (48).

7. Sensor assembly (82) according to claim 6, characterized in that the direction of extension of the material weakening (48), which is formed to be continuous in the direction of extension, changes along its extension, so that the material weakening (48) encloses a deformation region (52) of the sensor bracket (10), wherein the at least one release-locking formation (60a, 60b, 60c) is arranged in the deformation region (52).

8. Sensor assembly (82) according to any one of the preceding claims, characterized in that the release-locking formation (60a, 60b, 60c) over a predetermined circumferential extension range has a smaller thread groove depth in the thread groove (22a) of the locking thread (22) compared to a thread groove section free of a release-locking formation (60a, 60b, 60c).

9. Sensor assembly (82) according to claim 8, characterized in that the release-locking formation (60a, 60b, 60c) has a cross-section reduction section (63) in which the thread groove depth decreases gradually and / or continuously in the circumferential extension region along the extension of the thread groove in the direction from a screw-in start (36) to a screw-in end (38) of the locking thread (22) with respect to a screw-in process of the sensor bracket (10) into the sensor carrier (34).

10. Sensor assembly (82) according to claim 9, characterized in that the release-locking formation (60a, 60b, 60c) has, in the direction from the screw-in start (36) to the screw-in end (38), following the cross-section reduction section (63), a cross-section enlargement section in which the thread depth in the circumferential extension region increases stepwise or / and continuously in the direction from the screw-in start (36) to the screw-in end (38).

11. Sensor assembly (82) according to one of claims 8 to 10, characterized in that the release-locking formation (60a, 60b, 60c) has a boundary surface (62) which extends axially with respect to the screw axis (S) of the locking thread (22) between thread flanks (24a, 24b) which confine the thread groove (22a), the radial distance of the boundary surface (62) from the screw axis (S) changing along the circumferential extent of the boundary surface (62).

12. Sensor assembly (82) according to claim 11, characterized in that the boundary surface (62) forms an apex region (64) in which the cross-sectional area (Q) of the thread groove (22a) along the circumferential extension region of the release-locking formation (60a, 60b, 60c) is minimal.

13. Sensor assembly (82) according to any one of the preceding claims, characterized in that it comprises a plurality of release-locking formations (60a, 60b, 60c) which are arranged one behind the other in a thread.

14. Sensor assembly (82) according to claim 13, characterized in that the release-locking formations (60a, 60b, 60c) arranged one behind the other cause a different reduction in the cross-sectional area (Q) of the thread groove (22a).

15. Sensor assembly (82) according to claim 13 or 14, including claim 7, characterized in that the plurality of release-locking formations (60a, 60b, 60c) are arranged in the deformation area (52).

16. Sensor assembly (82) according to any one of claims 7 to 15, including claim 7, characterized in that the release-locking formation (60a, 60b, 60c) or, in the case of a plurality of release-locking formations (60a, 60b, 60c), that release-locking formation (60c) with the largest cross-sectional reduction is arranged in that thread groove portion of the deformation region (52) which has the greatest distance from a shortest virtual connecting line (50) within the deformation region (52), the virtual connecting line (50) connecting both ends of the material weakening (48) enclosing the deformation region (52) at a constant radial distance from the screw axis (S) of the locking thread (22).