Fastening system including quick coupler

Abstract

The invention relates to a fastening system with a quick coupling. It comprises an insert for fastening a specimen head to a holding system rigidly connected to a magnet on the bottom side, which forms a force-varying connection by means of at least one spring element, the specimen head being fastened to the insert by means of the holding element, and when the spring element is under tension, a connection without mechanical play exists between the insert and the holding element in the closed state, a prestressing element is arranged between the insert and the holding system, the prestressing element presses the spring element by rotating about its disk axis relative to the insert and thereby prestresses the spring element, and the spring element and the holding element are geometrically designed such that, while the spring element is prestressed by the prestressing element, in the open state, a connection with a mechanical play of 0.5 mm to 5 mm exists between the insert and the holding element. This significantly reduces friction and wear of movable components during installation and removal, and one-handed assembly is also possible.

Description

Technical Field

[0001] The invention relates to a fastening device for detachably fastening an NMR specimen head to an NMR magnet, the main axis of the NMR specimen head extending parallel to the z-direction, the fastening device comprising an insert which is provided for sliding from below, for fastening the NMR specimen head, onto a holding system which is arranged on the underside of the NMR magnet and is rigidly connected to the magnet, the holding system being part of the fastening device, wherein after the NMR specimen head has been pushed toward the underside of the insert facing away from the holding system until the upper end of the specimen head comes into contact with the upper end of the holding system, a fixed mechanical connection can be established between the specimen head and the insert on the one hand and between the insert and the holding system on the other hand, wherein the insert is designed such that a force-varying connection between the specimen head and the holding system can also be established in addition to the form fit by means of at least one spring element, wherein the specimen head can be fastened to the insert by means of a plurality of respectively one-piece rigid holding elements of respectively non-variable fixed length, the holding elements being part of the fastening device, and wherein in the closed state a connection without mechanical play exists between the insert and the holding elements while the spring elements are under mechanical stress. Background Art

[0002] Such an arrangement is known from DE 10 2017 215 763 B3 (=reference [1]).

[0003] NMR methods are used to analyze sample components or to determine the structure of materials in a sample. NMR spectroscopy is an effective method for instrumental analysis. In the NMR method, the sample is subjected to a strong static magnetic field B0 in the z direction. This causes an interaction with the nuclear spins of the sample material, in particular for the orientation of the nuclear spins in the measured substance. A high-frequency electromagnetic pulse orthogonal to this is then radiated into the sample in the x or y direction. The temporal evolution of the nuclear spins of the sample again generates a high-frequency electromagnetic field, which is detected in the NMR device. From the detected HF field, information about the properties of the sample can be obtained in an integrated manner over a certain spatial region. In particular, the chemical composition and chemical bonding relationships in the sample can be inferred from the position and intensity of the NMR lines (see, for example, DE 10 2013 204 131 B3 = reference [2]).

[0004] The measurement sample usually comprises a cylindrical sample tube with a generally circular, oval or rectangular cross section, which contains a solid or liquid measurement substance. The sample tube is closed at least on the side with which it first penetrates into the sample head and is typically located in a rotator. The sample tube and the rotator are transported from outside the magnet into the sample head by means of a transport system. It is then assumed that the introduction opening is located at the top of the sample head and the sample tube is introduced into the sample head from above. However, it is also conceivable that the sample tube is introduced into the sample head from below into an opening provided for this purpose. This situation is similar to the above situation and is not described in detail for reasons of clarity. When the sample tube is in the measurement position, the rotator is located within the turbine. The turbine enables the sample tube to be rotated (see, for example, DE 10 2013 212 312 B4 = reference [3]).

[0005] The company manual “Manual Probes. User Manual Version 003” of Bruker BioSpin AG from September 2009 (= reference [4]) describes, in particular in Chapters 5.2 and 5.8, a fastening device for releasably fastening an NMR sample head to an NMR magnet, comprising a disc-shaped insert which is designed in such a way that a force-varying connection between the sample head and the holding system can also be constructed by means of a spring element in addition to the form fit.

[0006] The so-called "standard bore" specimen heads available today are fastened to the SHIM system by means of two screws. This is very cumbersome for the user, since he must crawl under the magnet to mount the specimen head and work there in a kneeling position. On the other hand, the relatively small screws are very cumbersome due to the mounting position of the specimen head on the magnet and can usually only be tightened with a special screwdriver.

[0007] When the fastening screw is tightened, the fastening is fixed and can no longer adapt to subsequent length changes, which can be caused, for example, by temperature changes. These length changes can then cause mechanical play or impermissible axial tensions between the specimen head and the holding system.

[0008] Today's so-called "wide bore" specimen heads are mounted on the holding system using a quick-release closure known per se. Due to the structurally determined slot shape of the clamping system, the maximum force is already applied to the specimen head at the beginning of the assembly process when the tensioning ring is actuated. After overcoming this maximum force, the system releases the tension again and the specimen head is mounted in the SHIM system of the NMR system with an undefined force and a play that may no longer be tolerable.

[0009] In order to avoid these difficulties, the holding element must currently be set specifically to the corresponding SHIM system in each specimen head. However, the set force may not be controlled here. It may only be tested whether there is or is not a mechanical play (tolerable or no longer tolerable).

[0010] These circumstances made it impossible until recently to use the quick-release fastening already known from the “Wide Bore” specimen head according to reference [4] for assembling the “Standard Bore” specimen head, since in the case of the “Standard Bore” specimen head it is very important that there is no play at all or no excessively high forces between the specimen head and the SHIM system.

[0011] For this reason, the known quick-release closures of “Wide Bore” specimen heads according to reference [4] do not have a lock to prevent accidental opening. However, this is a fixed requirement for “Standard Bore” specimen heads due to safety considerations and the resulting market considerations.

[0012] US 2009 / 0 015 259 A1 (=reference [5]) describes a completely general system and method for fastening an instrument to an NMR system.

[0013] In contrast to the previously conventional embodiments, similar fastening devices according to the reference [1] cited above always have a defined force in a certain region in the assembled state, both for "wide bore" and for "standard bore" specimen heads, which exists between the specimen head and the holding system. The spring element is designed there in such a way that the holding force increases continuously when the holding element is actuated and reaches its maximum value in the end position. Due to this design of the spring element, which is already known per se, it is no longer possible to produce a gap between the specimen head and the NMR magnet system or SHIM system in the assembled end position.

[0014] Due to the possibility of opening such a quick-release closure by means of a fastening device according to reference [1], it is no longer possible for the user to have to pay the price of operating errors when mounting the NRM specimen head on the holding system, for example when adjusting the holding element in a "Wide Bore" system. Since in the quick-change system according to the invention the length tolerances of the components involved are accommodated by means of the spring element, the system can no longer be in a mechanically uncertain state.

[0015] Of course, the significantly improved fastening device disclosed in reference [1] still has the following disadvantages:

[0016] The friction of the rotating spring element causes wear on the retaining element.

[0017] The friction between these two components results in relatively high actuation forces.

[0018] At least two hands are required to install the NMR specimen head: one hand to hold the NMR specimen head and the other hand to actuate the locking device.

[0019] The assembly of the quick-release closure on the shim system (ie above the head) is complicated by the prestressed spring element. Summary of the invention

[0020] Mission of the present invention

[0021] In contrast, the object of the present invention is to improve a fastening device of the type defined at the outset by means of technical measures that are as simple as possible in such a way that the above-mentioned disadvantages are completely or at least largely avoided without thereby causing a reduction in the quality of the NMR measurement, wherein the NMR specimen head should remain particularly compact and the material and production costs should be reduced.

[0022] A further object of the present invention is to enable a rapid replacement of the specimen head without the risk of significantly shortening the service life of the specimen head as a result.

[0023] Brief description of the invention

[0024] This object is achieved in an equally unexpectedly simple and very effective manner in that, in a similar fastening device having the features defined at the outset, a washer-shaped preloading element is provided between the insert and the retaining system, the preloading element being designed in such a way that, by rotation of the preloading element about its disk axis relative to the insert, the preloading element presses against the spring element and thereby preloads the spring element, and the spring element of the insert and the retaining element are geometrically designed in such a way that, while the spring element is preloaded by the preloading element, in the open state a connection with a mechanical play of 0.5 mm to 5 mm exists between the insert and the retaining element.

[0025] In the solution known from reference [1], the spring element is brought into engagement with the holding element on the specimen head by twisting and is then tensioned by further rotation. In contrast, according to the teaching of the present invention, the insert with the two spring elements is no longer rotated but is fixed. Instead, the spring elements are flattened for mounting the specimen head and thereby pre-tensioned.

[0026] With the solution according to the invention, friction due to the rotating spring element which, in retaining elements of the prior art, leads to increased wear due to the relatively high required actuating forces between the two components, is never generated.

[0027] The prestressing of the spring element, the mounting of the specimen head and the release of the spring element are carried out step by step in succession, so that the mounting of the NMR specimen head can now even be carried out with one hand, since it is no longer necessary to hold the NMR specimen head with one hand while the other hand actuates the locking device, but the specimen head can now be introduced into the shim system together with the fastening device.

[0028] The previously relatively complicated assembly of the quick-release fastener on the shim system over the head is noticeably facilitated by the prestressed spring element. A simple rotation of the prestressing element designed according to the invention then results in the final tightening of the NMR specimen head.

[0029] It should be pointed out here that the advantages of the invention can be achieved not only in vertical NMR spectrometers, but also in NMR systems with a horizontal or inclined z-axis. The specified axial position then no longer necessarily needs to be "above" or "below" the NMR excitation coil system, but can also be "to the right" or "to the left" next to it if necessary. In any case, gravity plays a secondary role in the mode of action of the invention.

[0030] Preferred embodiments of the present invention

[0031] Depending on the particular purpose of use, the following embodiment of the fastening device according to the invention may be useful, in which the washer-shaped preload element is made of a non-magnetic material, preferably spring bronze. In particular, the disk-shaped insert may have a non-magnetic material, preferably spring bronze, for example Made of spring connection (Federkulisse).

[0032] Advantageously, no additional forces act on the mechanical device, which are caused by the interaction of the NMR magnet and the magnetic material. In addition, the magnetic material can lead to field disturbances, which can then affect the NMR measurement.

[0033] In an advantageous further development of these embodiments, the spring connection is designed in one piece. This can be achieved in a particularly simple manner, firstly by enabling cost-effective production (no assembly work) and secondly by enabling more optimal use of the installation space. In a one-piece element, no connecting parts are required, which require installation space. This installation space can be used for the spring strength and the spring length. This in turn results in more spring travel.

[0034] Particularly preferred is an embodiment of the fastening device according to the invention in which at least two, preferably three or four, spring elements are arranged evenly distributed about an axis perpendicular to the plane of the insert, so that no tilting moments are generated during actuation.

[0035] A preferred type of embodiment of the invention is characterized in that a holding section which is rigidly secured can be reversibly mounted on the underside of the holding system facing away from the magnet. The advantage is that the quick-release closure can be retrofitted to an already installed NMR magnet or holding system.

[0036] In an advantageous further development of this type of embodiment, the retaining section is annular and has a radially inwardly projecting nose on its radial inner side for each spring element of the insert, wherein the fastening device is also held together as a quick-release unit under the prestressing of the spring elements caused by the rotation of the prestressing element about its disk axis relative to the insert. The nose of the retaining section makes it possible for the entire quick-release unit to be held together under the prestressing of the spring elements. In other words, it is possible to prestress the spring elements by rotating the roller carrier, which simplifies the assembly of the quick-release unit on the shim system, since the spring elements do not have to be tensioned by the assembly itself. This assembly simplification is particularly welcome, since the assembly, as already mentioned, must be carried out above the head and under the magnet.

[0037] Another particularly preferred embodiment of the present invention is characterized in that the spring element has a fork-shaped receptacle at its respective free end, into which the holding element can be hooked during assembly by means of a rotation of the specimen head about its axis. The specimen head can thus be introduced into the shim system and hooked with its holding element in the fork of the spring element by means of a small rotational movement about the Z axis. By rotating the preload element back, the spring element is released and thus relaxed until the specimen head with its holding element is fixed in the end position.

[0038] An advantageous further development of this type of embodiment is characterized in that a projection is provided on the preload element in cooperation with each fork-shaped receptacle of the spring element, said projection being located on the corresponding retaining element in order to prevent the specimen head from being able to be rotated back about its axis by the action of force on the specimen head, so that the retaining element can slip out of the fork-shaped receptacle, wherein the spring element is released by the rotation back of the preload element and relaxes until the specimen head is fixed with its retaining element in the end position, thereby preventing the specimen head from accidentally falling down.

[0039] In a particularly preferred variant of this further development, there is a locking device to prevent accidental release of the holding device, wherein the locking device locks into place when the preload element is further rotated until it comes to abutment, and in this process, a projection on the preload element located on the holding element prevents the specimen head from being rotated back and the holding element from sliding out of the fork-shaped receptacle. By means of such a locking mechanism, the new fastening system is always protected against accidental opening.

[0040] The steps for assembling the specimen head and, in reverse order, for disassembling can be performed with one hand, which is advantageous in particular in the restricted spatial conditions under the NMR magnet.

[0041] For many practical uses, an embodiment of the invention is advantageous in which the insert is designed in the form of disk segments and each disk segment of the insert carries a spring element. That is, instead of an insert comprising a spring element, a separate spring element is mechanically connected to the holding segment. The main idea behind the separate spring element is that, on the one hand, less material (e.g. relatively expensive), and on the other hand, the spring element is integrated into the holding section when the holding section is produced using injection molding technology.

[0042] In an advantageous further development of this type of embodiment, a sliding support is provided between the preload element and the retaining system. The advantage is that the operating forces are minimal. The sliding support is much simpler to assemble than the ball bearing of the WB.

[0043] Alternatively or additionally, in a preferred further development a sliding support can also be provided between the preload element and the spring element.

[0044] These variants can finally be further improved by selecting the material of the sliding parts in the sliding support so that the operating forces and wear are minimized, wherein PET-C and spring bronze are preferably used as sliding parts. The advantage is that this material selection allows the main components (insert and retaining element) to be used directly as sliding parts.

[0045] In an alternative type of particularly preferred embodiment of the invention, the insert is disc-shaped and the preload element is formed as a roller carrier with rollers arranged thereon. This essentially only produces rolling friction, so that the actuating forces are still small, so that when the device is actuated, less wear is produced on the retaining element.

[0046] A further development of this type of embodiment is advantageous in which at least some of the rollers of the preload element are designed as tensioning rollers which, when the preload element is rotated about its disk axis relative to the insert, press against the spring element and thereby preload it.

[0047] Alternatively or in addition, other advantageous further developments are characterized in that at least a portion of the rollers of the preload element are implemented as support rollers which are pressed onto a retaining system and which roll with low friction on the retaining system, in particular on a base plate of a shim system of an NMR magnet, when the preload element rotates about its disk axis relative to the insert for field shaping of a uniform magnetic field in the NMR spectrometer.

[0048] To mount the specimen head, the spring element is pretensioned by rotating the roller carrier with the tensioning rollers arranged thereon, which press against the spring element. The upwardly offset support rollers run on the base plate of the shim system, where the entire quick-release closure unit is fastened thereto.

[0049] By rotating the roller support back, the spring element is released and relaxed (tension is relieved) until the specimen head is fixed with its holding element in the end position. If the roller support is rotated further until it comes to a stop, the locking device is locked. In this case, the projection on the roller support that contacts the holding element prevents the specimen head from rotating back about the Z axis due to the force acting on the specimen head and thus the holding element could slip out of the fork, which would cause the specimen head to fall off.

[0050] In a further preferred embodiment of the invention, the disk-shaped insert is designed as a quick-fit device, preferably as a bayonet closure, which is rotatable in particular about a disk axis parallel to the z-direction. Such an arrangement has the significant advantage of having a very short actuation stroke for the assembly of the specimen head on the holding system.

[0051] In practice, an embodiment of the fastening device according to the invention has also proven to be feasible in which the holding system is designed as a shim system for field shaping of a homogeneous magnetic field in an NMR spectrometer.

[0052] The invention also includes an NMR measuring device comprising a fastening device according to the invention of the type described above, which can have an NMR magnet system and, if appropriate, also a shim system and a cryostat.

[0053] Further advantages of the present invention are apparent from the description and the drawings. The above-mentioned and further described features can also be used according to the present invention individually or in multiple combinations in any desired manner. The embodiments shown and described are not to be understood as a final enumeration, but rather have an exemplary nature for describing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] DETAILED DESCRIPTION OF THE PRESENT INVENTION AND THE DRAWINGS

[0055] The invention is described in the drawings and explained in more detail with reference to exemplary embodiments.

[0056] in:

[0057] Figure 1a A schematic spatial side view from above showing a first embodiment of a fastening device according to the invention comprising a washer-shaped prestressing element without rollers;

[0058] Figure 1b Shown as an exploded view Figure 1aThe layout structure;

[0059] Figure 2a A schematic spatial side view from above of a second embodiment of the fastening device according to the invention comprising a washer-shaped prestressing element designed as a roller support with rollers arranged thereon;

[0060] Figure 2b Shown as an exploded view Figure 2a The layout structure;

[0061] Figure 3 A schematic vertical cross-section showing an NMR spectrometer comprising a fastening device according to the invention; and

[0062] Figure 4 A schematic longitudinal section through a specimen head mounted on a holding system using a fastening device according to the invention is shown, and more precisely in the left image half (O) in a first open state between insert and holding element and in the right image half (G) in a second closed state. DETAILED DESCRIPTION

[0063] In summary, the invention relates to an improved fastening device for the detachable fastening of an NMR specimen head 1 on an NMR magnet 2, the main axis of which extends parallel to the z-direction, the fastening device comprising an insert 3 which is provided for the purpose of sliding the NMR specimen head 1 from below onto a holding system 4 which is arranged on the underside of the NMR magnet 2 and is rigidly connected to the magnet 2, the holding system being part of the fastening device, wherein after the NMR specimen head 1 has been pushed toward the underside of the insert 3 facing away from the holding system 4 until the upper end of the specimen head 1 comes into contact with the upper end of the holding system 4, a secure connection can be established on the specimen head 1. A fixed mechanical connection between the specimen head 1 and the insert 3 and, on the other hand, between the insert 3 and the holding system 4, wherein the insert 3 is designed such that, in addition to the form fit, a force-varying connection between the specimen head 1 and the holding system 4 can also be formed by means of at least one spring element 8, wherein the specimen head 1 can be fastened to the insert 3 by means of a plurality of rigid holding elements 6, each of which is one-piece and each has an unchangeable fixed length, which are part of the fastening device, and wherein, while the spring element 8 is under mechanical stress, a connection without mechanical play exists in the closed state between the insert 3 and the holding element 6.

[0064] In contrast, the present invention is characterized in that a washer-shaped preload element 9 is provided between the insert 3 and the retaining system 4, said preload element being designed in such a way that, by rotation of the preload element 9 about its disk axis relative to the insert 3, the preload element 9 is pressed onto the spring element 8 and thereby preloads said spring element.

[0065] According to the invention, the spring element 8 of the insert 3 and the retaining element 6 are also geometrically designed such that when the spring element 8 is prestressed by the prestressing element 9 , in the open state there is a connection with a mechanical play of 0.5 mm to 5 mm between the insert 3 and the retaining element 6 .

[0066] The holding force usually increases continuously when the holding element 6 is actuated and reaches its maximum value in the end position in the second closed state.

[0067] The disk-shaped insert 3 is usually designed such that a force-varying connection between specimen head 1 and holding system 4 can also be formed by means of spring elements 8 in addition to the form fit, wherein the spring elements 8 are designed such that when they are actuated a spring travel of f≧2 mm is triggered.

[0068] Figure 1a , 1b , 2a and 2b show a particularly preferred embodiment in which a holding section 5 can be reversibly mounted on the underside of the holding system 4 facing away from the magnets, said holding section 5 being rigidly fastened to the insert 3. In the mounted state, the holding section 5 radially surrounds the insert 3 and acts as a protective housing.

[0069] The holding section 5 can be annular and have a radially inwardly protruding nose 14 on its radial inner side for each spring element 8 of the insert 3, wherein the fastening device is also held together as a quick-release unit under prestressing of the spring element 8 caused by the rotation of the prestressing element 9 about its disk axis relative to the insert 3. The nose 14 holds the prestressing element 9. The required number of noses 14 is therefore independent of the number of spring elements 8.

[0070] The spring elements 8 preferably have a fork-shaped receptacle 12 at their respective free ends, into which the holding element 6 can be hooked during assembly by rotating the specimen head 1 about its axis.

[0071] In the illustrated embodiment, a projection 13 is provided on the preload element 9 in cooperation with each fork-shaped receptacle 12 of the spring element 8, said projection being located on the corresponding retaining element 6 in order to prevent the specimen head 1 from being able to be rotated back about its axis by the action of a force on the specimen head 1, so that the retaining element 6 can slide out of the fork-shaped receptacle 12, wherein the spring element 8 is released by the rotation back of the preload element 9 and is relaxed to such an extent that the specimen head 1 is fixed with its retaining element 6 in the end position.

[0072] Furthermore, there is a locking device 7 here to prevent an accidental release of the holding device, wherein the locking device 7 locks into place until it comes to a stop when the preload element 9 continues to rotate, and at the same time prevents the specimen head 1 from rotating back and the holding element 6 from sliding out of the fork-shaped receiving portion 12 by a projection 13 on the preload element 9 located on the holding element 6.

[0073] As in Figures 1a to 2b As can be further seen in FIG, the spring connection of the disk-shaped insert 3 can be constructed in one piece. Usually it is made of non-magnetic material, such as spring bronze.

[0074] Preferably, a sliding support (not specifically shown in the figures) can be provided between the preload element 9 and the holding system 4 and, alternatively or additionally, between the preload element 9 and the spring element 8. The material of the sliding partner in the sliding support is then selected such that the operating forces and wear are minimized, wherein PET-C and spring bronze are preferably used as sliding partners.

[0075] Instead of the fastening device according to the invention Figure 1a and 1b The continuous annular insert 3 of the embodiment shown in , can - in embodiments not specifically shown in the figures - also be designed as a disk segment-shaped insert, each disk segment of the partial insert being provided with a spring element 8 .

[0076] Figure 2a and 2b A particularly preferred embodiment is shown, in which the insert 3 is again designed in the form of a washer and the prestressing element 9 is designed as a roller carrier with rollers arranged thereon. In this case, a part of the rollers of the prestressing element 9 is designed as tensioning rollers 10, which press against the spring element 8 when the prestressing element 9 is rotated about its disk axis relative to the insert 3 and thus prestress the spring element.

[0077] Another part of the roller is designed as a support roller 11 which is pressed onto the retaining system 4 and, when the preload element 9 is rotated about its disk axis relative to the insert 3 , rolls with low friction on the retaining system 4 , in particular on the base plate of the shim system of the NMR magnet 2 , for field shaping of a uniform magnetic field in an NMR spectrometer.

[0078] Figure 3The schematic diagram shows how the fastening system according to the invention enables a fast mounting or dismounting of an NMR specimen head 1 on an NMR magnet 2. To this end, a disk-shaped insert 3 is first pushed from below onto the underside of a holding system 4 provided in the NMR magnet 2 and rigidly connected to the magnet 2, to which the NMR specimen head 1 is fastened by means of holding elements 6. Subsequently, by rotating the insert 3 about its disk axis, a fixed mechanical connection is established between the specimen head 1 and the insert 3 on the one hand, and between the insert 3 and the holding system 4 on the other hand.

[0079] The holding system 4 can also be designed as a shim system for field shaping of a homogeneous magnetic field in an NMR spectrometer.

[0080] Figure 4 Finally, a schematic longitudinal section through the specimen head 1 mounted on the holding system 4 illustrates how the relative distances of the participating system components behave according to the invention in two emphasized mounting states, and more precisely in the left half of the figure (indicated by "O") in a first, open state between the insert 3 and the holding element 6, and in the right half of the figure (indicated by "G") in a second, closed state:

[0081] In geometric relationship

[0082] (L5_min+L3_min)-(L4_max–L2_min)=dHE_min

[0083] (L5_max+L3_max)-(L4_min–L2_max)=dHE_max

[0084] The following geometric conditions must be met:

[0085] For a geometry without gaps:

[0086] L1>dHE_max

[0087] Geometric conditions for assemblability:

[0088] dHE_max>0

[0089] This means:

[0090] L1 Untensioned height of spring element 8

[0091] L2 Height of holding element 6

[0092] L3 Height of insert 3

[0093] L4 NMR sample height

[0094] L5 Height holding system 5

[0095] dHE gap between insert 3 and retaining element 6

[0096] Reference numerals list

[0097] 1 NMR sample head

[0098] 2 NMR magnets

[0099] 3 Inserts

[0100] 4. Maintain the system

[0101] 5. Keep Section

[0102] 6. Retaining element

[0103] 7 Locking device

[0104] 8 Spring element

[0105] 9 Washer-shaped preload element

[0106] 10 Tension roller

[0107] 11 Support roller

[0108] 12 Fork-shaped receiving portion

[0109] 13 Protrusion

[0110] 14 Protruding nose

[0111] References

[0112] Publications used to assess patentability considerations:

[0113] [1]DE 10 2017 215 763 B3≈EP 3 454 068 B1≈CN 109471052 B≈US 10 379179 B2

[0114] [2]DE 10 2013 204 131 B3

[0115] [3]DE 10 2013 212 312 B4

[0116] [4] Bruker BioSpin AG, September 2009, “Manual Probes. User Manual Version 003”

[0117] [5] US 2009 / 0 015 259 A1

Claims

1. A fastening device for releasably fastening an NMR sample head (1) to an NMR magnet (2), wherein the main axis of the NMR sample head extends parallel to the z-direction, the fastening device comprising an insert (3) which is arranged to be pushed from below onto a holding system (4) arranged on the underside of the NMR magnet (2) and rigidly connected to the NMR magnet (2) for fastening the NMR sample head (1), the holding system being part of the fastening device, wherein: After the NMR specimen head (1) has been pushed toward the lower side of the insert (3) facing away from the holding system (4) until the upper end of the NMR specimen head (1) contacts the upper end of the holding system (4), a fixed mechanical connection can be established between the NMR specimen head (1) and the insert (3) on the one hand and between the insert (3) and the holding system (4) on the other hand, wherein the insert (3) is designed such that a positive and force-changing connection between the NMR specimen head (1) and the holding system (4) can be formed by means of at least one spring element (8), wherein the NMR specimen head (1) can be fastened to the insert (3) by means of a plurality of rigid holding elements (6) each of which is integral and has a fixed, non-variable length, the holding elements being part of the fastening device, and while the spring elements (8) are under mechanical stress, in the closed state a connection without mechanical play exists between the insert (3) and the holding elements (6), It is characterized in that A washer-shaped preload element (9) is arranged between the insert (3) and the retaining system (4), the preload element being designed such that, by rotating the preload element (9) about its disk axis relative to the insert (3), the preload element (9) presses against the spring element (8) and thereby preloads the spring element. Furthermore, the spring element (8) of the insert (3) and the retaining element (6) are geometrically designed so that when the spring element (8) is prestressed by the prestressing element (9), in the open state there is a connection with a mechanical play of 0.5 mm to 5 mm between the insert (3) and the retaining element (6).

2. The fastening device according to claim 1, characterized in that The washer-shaped prestressing element (9) is made of a non-magnetic material.

3. The fastening device according to claim 1, characterized in that There are at least two spring elements (8) which are arranged evenly distributed about an axis perpendicular to the plane of the insert (3).

4. The fastening device according to any one of claims 1 to 3, characterized in that A holding section (5) can be reversibly mounted on the underside of the holding system (4) facing away from the NMR magnet and is rigidly fastened to the insert (3).

5. The fastening device according to claim 4, characterized in that The retaining section (5) is annular in shape and has on its radial inner side a radially inwardly projecting nose (14) for each spring element (8) of the insert (3), wherein the fastening device is also held together as a quick-release unit under prestressing caused by the prestressing element (9) rotating about its disk axis relative to the insert (3).

6. The fastening device according to any one of claims 1 to 3, characterized in that The spring elements (8) have fork-shaped receptacles (12) at their respective free ends, into which the holding element (6) can be hooked during assembly by rotating the NMR specimen head (1) about its axis.

7. The fastening device according to claim 6, characterized in that A projection (13) is provided on the preload element (9) in cooperation with each fork-shaped receptacle (12) of the spring element (8), said projection being located on the corresponding retaining element (6) in order to prevent the NMR specimen head (1) from being able to be rotated back about its axis by the action of force on the NMR specimen head (1), so that the retaining element (6) can slip out of the fork-shaped receptacle (12), wherein the spring element (8) is released and relaxed by the rotation back of the preload element (9) until the NMR specimen head (1) is fixed with its retaining element (6) in an end position.

8. The fastening device according to claim 7, characterized in that A locking device (7) is provided to prevent accidental release of the holding device, wherein the locking device (7) is locked when the preload element (9) is further rotated until it comes into contact, and a projection (13) on the preload element (9) located on the holding element (6) prevents the NMR sample head (1) from being rotated back and prevents the holding element (6) from slipping out of the fork-shaped receiving portion (12).

9. The fastening device according to any one of claims 1 to 3, characterized in that The insert (3) is designed in the form of disk segments, and each disk segment of the insert (3) carries a spring element (8).

10. The fastening device according to claim 9, characterized in that A sliding support is arranged between the pretensioning element (9) and the retaining system (4).

11. The fastening device according to claim 9, characterized in that A sliding support is arranged between the preload element (9) and the spring element (8).

12. The fastening device according to claim 10 or 11, characterized in that The materials of the sliding partners in the respective sliding supports are selected such that the operating forces and wear are minimized.

13. The fastening device according to any one of claims 1 to 3, characterized in that The insert (3) is disk-shaped and the preload element (9) is designed as a roller carrier with rollers (10; 11) arranged thereon.

14. The fastening device according to claim 13, characterized in that At least a portion of the rollers of the preload element (9) are designed as tensioning rollers (10) which, when the preload element (9) is rotated about its disk axis relative to the insert (3), press against the spring element (8) and thereby preload the spring element.

15. The fastening device according to claim 13, characterized in that At least some of the rollers of the preload element (9) are designed as support rollers (11) which are pressed onto the retaining system (4) and roll with low friction on the retaining system (4) when the preload element (9) is rotated about its disk axis relative to the insert (3).

16. The fastening device according to claim 12, characterized in that PET-C and spring bronze are used as sliding parts.

17. The fastening device according to claim 15, characterized in that The support roller (11) rolls with low friction on a base plate of a shim system of an NMR magnet (2) for field shaping of a uniform magnetic field in an NMR spectrometer when the preload element (9) rotates about its disk axis relative to the insert (3).

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