Abstract:
A method and a fastening system for the releasable fastening of a component to an apparatus are described. Here the fastening system comprises a detent spring arranged on the apparatus, a detent pin with a groove arranged on the component and a Bowden cable arranged on the apparatus. If the component is fastened to the apparatus, the detent spring locks in the groove in a locking position. The Bowden cable is connected to the detent spring such that when pulling on the Bowden cable, the detent spring releases from the locking position in the groove, as a result of which the fastening of the component to the apparatus is released.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of German application No. 10 2009 023 858.1 filed Jun. 4, 2009, which is incorporated by reference herein in its entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to a method for fastening a component, for instance an inlet funnel, to an apparatus, for instance a system casing of an MR system, as well as a correspondingly configured fastening system. 
     BACKGROUND OF THE INVENTION 
     In the case of housing casings of MR systems, opposing requirements exist in terms of design, service and acoustics. On the one hand, the design should ensure that screw connections are as invisible as possible from the outside. On the other hand, the service requires all parts (inside the MR system) to be as easily accessible as possible, thereby almost inevitably requiring connecting elements which are easily visible from the outside. Furthermore, a vibration decoupling is advisable as a result of the acoustics, such that no direct screw connection with the base system of the magnet of the MR system is to be available. A screw connection of the inlet funnel of the MR system casing with the body coil (“HF pipe”, “bore”) generally results for instance in vibrations being transmitted from the body coil to the inlet funnel and this thus being induced to oscillate, thereby becoming negatively noticeable as noise in the manner of a loudspeaker. 
     SUMMARY OF THE INVENTION 
     It is thus the object of the present invention to improve the fastening of a casing in MR systems relative to the prior art. 
     This object is achieved in accordance with the invention by a fastening system a method for the releasable fastening of a component to an apparatus and a magnetic resonance system as claimed in the claims. The dependent claims define preferred and advantageous embodiments of the present invention. 
     Within the scope of the present invention, a fastening system is provided for the releasable fastening of a component to an apparatus. In this way, a detent spring fastened to the apparatus locks into a groove of a detent pin fastened to the component, with the detent spring being located in a locking position, if the component is fastened to the apparatus, i.e. if the detent spring is locked in the groove. Furthermore, a Bowden cable arranged on the apparatus is connected to the detent spring such that the detent spring can be released from the locking position in the groove by pulling on the Bowden cable, as a result of which the fastening of the component to the apparatus can also be released. 
     A corresponding arrangement of the detent spring, the detent pin and the Bowden cable enables the inventive fastening system to be configured such that no screw connections are visible from the outside and no decorative covers or other types of covers for screws are needed, as a result of which tool and part costs can be advantageously reduced compared with the prior art. 
     As it is only the detent spring that has to be locked in the groove of the detent pin, in order to attach the component to the apparatus, and only the Bowden cable that has to be actuated in order to release the component from the apparatus, the present invention has shorter disassembly and assembly times, by comparison with fastening systems as claimed in the prior art, which operate with a screw connection. 
     The fastening system also comprises a receptacle fastened to the apparatus, to which the detent spring is fastened. To fasten the component to the apparatus, the detent pin is inserted into the receptacle, with the detent spring in the locking position locking into the groove. To release the fastening of the component to the apparatus, the detent pin has to be guided out of the recess, the detent spring having being released (pulled) from the groove previously by actuating the Bowden cable, as a result of which the detent pin is no longer blocked by the detent spring and can be easily pulled out of the receptacle. 
     A first movement direction, in which the detent spring moves, is advantageously essentially at right angles to a second movement direction, in which the detent pin is moved into the receptacle when fastening the component to the apparatus and moved out of the receptacle when releasing the component from the apparatus. The second movement direction is also arranged here essentially in parallel to an axis of symmetry of the detent pin. The detent spring moves here in the first movement direction if the detent pin is guided into the recess or if the detent spring is moved by pulling on the Bowden cable. A movement direction is understood here to be both a forward direction and also a backward direction which is parallel to the forward direction. 
     In a preferred inventive embodiment of the fastening system, the receptacle has a bias spring fastened to the receptacle. When fastening the component to the apparatus, the detent pin is inserted into the receptacle counter to the bias spring, so that the bias spring is pretensioned after insertion of the detent pin into the receptacle. When releasing the fastening of the component from the apparatus, the detent pin is pushed out of the receptacle by the bias spring as a result of pretension (if the detent spring has previously been released from the locking position (from the groove) by way of the Bowden cable. 
     The bias spring almost automatically forces the detent pin out of the receptacle, provided it is no longer hindered by the detent spring and/or provided the Bowden cable is actuated. As a result, the component advantageously releases itself from the apparatus simply by actuating the Bowden cable, without a further manual operation by means of an operating person being needed herefor. 
     A direction of force, in which the bias spring is pretensioned upon insertion of the detent pin into the recess, is in particular essentially parallel here to the movement direction of the detent pin upon insertion into the receptacle or upon release from the receptacle. The direction of force is therefore essentially at right angles to the (previously described) first movement direction of the detent spring. 
     The detent pin advantageously has an upwardly tapered head, so that an insertion of the detent pin into the receptacle on the one hand and an insertion of the detent spring into the groove of the detent pin on the other hand is facilitated. This particularly facilitates the assembly, since large assembly tolerances are permitted, even if advantageously only small position tolerances are available. 
     Furthermore, the receptacle can comprise a stop, against which the detent spring strikes in the case of a pull by the Bowden cable, as a result of which a movement of the Bowden cable is limited when releasing the detent spring from the locking position in the groove, and the cable core of the Bowden cable (generally a non-magnetic wire or suchlike) is not overloaded (overstretched). 
     The detent spring can also further comprise a pretension, so that a tensile force applied to the detent spring by the Bowden cable has to release the detent spring from the locking position in the groove counter to the pretension. 
     In a preferred inventive embodiment of the fastening system, the fastening system has several of the previously described detent pints on the component and several of the previously described receptacles on the apparatus. Here the number of detent pins equates to the number of receptacles, with the detent pins being arranged on the component and the receptacles being arranged on the apparatus such that when fastening the component to the apparatus, each of the detent pins can be inserted into one of the receptacles. Furthermore, the fastening system according to this embodiment includes a releasing handle and a number of Bowden cables corresponding to the number of detent pins (or receptacles), said Bowden cables being actuated by way of the releasing handle. The Bowden cables are guided to the detent springs by the releasing handle such that each Bowden cable engages with one of the detent springs. When actuating the releasing handle, each detent spring is released from an engagement with the groove of its detent pin by way of the corresponding Bowden cable. 
     According to an inventive embodiment, the releasing handle has two detent points. With the first detent point, the releasing handle exerts almost no pull on the Bowden cables, so that the detent springs are locked into the grooves of the detent pins, if the component is attached to the apparatus. In the second detent point, which also retains the releasing handle, if the releasing handle is disengaged, the releasing handle exerts such a pull on the Bowden cable that all detent springs release out of the grooves and release the detent pins. On condition that the receptacles have no bias springs, the second locking point is used to release the engagement between the component and the apparatus, without releasing the component from the apparatus. To release the component from the apparatus, the component must be detached from the apparatus in this embodiment. 
     By each component having several detent pins and each apparatus having several receptacles, several detent pins can advantageously be arranged around an edge of the component, as a result of which the component can at the same time be fastened to the apparatus at several points. 
     Here the fastening system can include a power distributor and an additional Bowden cable. The additional Bowden cable is guided here to the force distributor by the unlocking handle, while the Bowden cables are guided from the force distributor to the assigned detent spring in each instance. Upon actuation of the unlocking handle, a force is transmitted from the unlocking handle, via the additional Bowden cable, to the force distributor and from the force distributor to the several Bowden cables and from there to the detent springs. 
     A length of the additional Bowden cable can be measured here such that the unlocking handle can be moved outside the apparatus in front of the component and can be actuated there. As a result, the component can be released by actuating the unlocking handle while the component can on the one hand be monitored by the operating person controlling the unlocking handle and if necessary, also be guided or moved manually. 
     The fastening system can also include an adjustable screw for each Bowden cable, with it being possible, with the aid of these adjustable screws, for a force transmission to be adjusted from the additional Bowden cable to the Bowden cable corresponding to the adjustable screw. If settling occurs on the section of a Bowden cable, this can herewith be balanced out. 
     The Bowden cables, the force distributor, the additional Bowden cable and the unlocking handle are preferably arranged here within the apparatus, in order not to interfere with the optical image of the apparatus (for instance a magnetic resonance system). E.g. by opening a service flap of the magnetic resonance system, the unlocking handle can then be removed from the apparatus in order to release the component from the apparatus. 
     To facilitate the fastening of the component to the apparatus, the component can include one or several guiding ridges, which are arranged on the periphery of the component. With the aid of the guide ridge or ridges, the component can be easily arranged in a position, in which the detent pins are inserted into the receptacles. 
     Furthermore, the fastening system can also include a securing leash, with which the component is attached to the apparatus so that when releasing the component from the apparatus (by actuating the unlocking handle), the component is prevented from falling out of the apparatus by means of a securing leash. In more precise terms, the length of the securing leash restricts the fall of the component, i.e. the length of the securing leash is generally defined such that the component does not fall onto the ground and/or onto the feet of the operating and/or service personnel, if it is released from the apparatus. To completely release the component from the apparatus, the securing leash must be manually released from the component or from the apparatus. 
     Within the scope of the present invention, a method for the releasable fastening of a component to an apparatus is also provided. When fastening the component to the apparatus, a detent spring arranged on the apparatus is engaged here with a groove of a detent pin arranged on the component such that the component is herewith fastened to the apparatus. When releasing the component from the apparatus, a Bowden cable is actuated, so that the engagement between the detent spring and the groove is released by actuating the Bowden cable. 
     The advantages of the inventive method essentially correspond to the advantages of the inventive fastening system, which are described in detail above, so there is no need for a repetition here. 
     The present invention is particularly suited to fastening a casing (component) to a magnetic resonance system (apparatus) or to fastening an inlet funnel (component) to a casing of a magnetic resonance system. The present invention is naturally not restricted to these preferred areas of application but can instead by used to fasten any components to any apparatuses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described in detail below with the aid of preferred embodiments with reference to the figures, in which; 
         FIG. 1   a  represents an overview of a casing of a magnetic resonance system. 
         FIG. 1   b  shows an exploded view of the components of the casing in  FIG. 1   a.    
         FIG. 2  represents the inlet funnel attached to the casing when viewed from inside the casing. 
         FIG. 3  shows a detailed representation of the inlet funnel attached to the casing when viewed from inside the casing. 
         FIG. 4  represents an inventive force distributor. 
         FIG. 5  represents an inventive unlocking handle. 
         FIG. 6  represents an inventive detent pin. 
         FIG. 7  represents an inventive receptacle. 
         FIG. 8  is a side representation of an inventive receptacle with a detent pin locked therein. 
         FIG. 9  represents a top view of an inventive receptacle with a detent pin locked therein. 
         FIG. 10  represents inventive guiding ridges. 
         FIG. 11  represents a design sketch of an inventive fastening system. 
         FIG. 12  represents a design sketch of the individual components of an inventive fastening system. 
         FIG. 13  represents a design sketch of an inventive fastening system from below. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1   a  shows an inventive casing  1  of a magnetic resonance system  20 , to which an inlet funnel  9  is attached with the aid of the present invention. 
       FIG. 1   b  represents an exploded view of components of the casing of the magnetic resonance system. 
       FIG. 2  shows an overall interior view of a rear and/or front casing of a magnetic resonance system with inventive rapid locking and unlocking system for fastening an inlet funnel  9  to the casing  1 . An unlocking handle  11  and a force distributor  12  can be seen on the inside. Bowden cables  13  are guided from the force distributor  12  to four receptacles  17 . A further Bowden cable  21  is located between the unlocking handle  11  and the force distributor  12 . By actuating the unlocking handle  11 , a force is guided to the force distributor  12  by way of the further Bowden cable  21 , which then forwards this force to the Bowden cables  13 , as a result of which the inlet funnel  9  is released, as is described again in detail below. Furthermore, a securing leash  18  is shown in  FIG. 2 , with which the inlet funnel  9  is attached to the casing  1 , in order to prevent the inlet funnel  9  from falling onto the floor or from falling onto the feet of an operating person and/or damaging the casing  1  when the inlet funnel  9  is released from the casing  1 . 
     A section of  FIG. 2  is shown in detail in  FIG. 3 . 
       FIG. 4  shows the force distributor  12  in detail. When actuating the unlocking handle  11 , a force is applied to the force distributor  12  by way of the further Bowden cable  21  by means of a sphere  21   a . The force distributor  12  then in turn forwards this force via a sphere  13   a  to the four Bowden cables  13  in each instance. Each Bowden cable  13  can therefore be mounted in the force distributor  12  or released from the force distributor  12  by means of its sphere  13   a.    
       FIG. 5  represents an unlocking handle  11  at close range. This unlocking handle  11  is normally arranged inside the casing  1  and/or magnetic resonance system  20 . The unlocking handle  11  can however be guided out of the casing  1  in order to release the inlet funnel  9  from the casing  1 , if the length of the further Bowden cable  21  connected to the unlocking handle  11  enables this. 
       FIG. 6  shows a detent pin  16  at close range. An upwardly tapered head  23  of the detent pin  16  can be seen, with the aid of which an insertion of the detent pin  16  into a receptacle  17  and thus a locking of a detent pin  16  in a groove  22  of the detent pin  16  is facilitated. 
       FIG. 7  shows a side view of a receptacle  17 , from which the detent pin  16  is inserted into the receptacle  17  in order to fasten the inlet funnel  9  to the casing  1 . 
       FIG. 8  shows a receptacle  17  obliquely from the side, with a detent pin  16  locked to the detent spring or a round wire spring  14  of the receptacle  17  being located in the receptacle  17 . It is apparent that the detent pin  16  engages with the round wire spring  14 , although a force is exerted onto the detent pin by means of a leaf spring  15  of the receptacle  17 . It is only when the Bowden cable  13  which is fastened to the round wire spring  14  by way of an eyelet  24  is actuated that the round wire spring  14  is pulled out of the groove  22 , so that the engagement between the round wire spring  14  and the detent pin  16  releases, as a result of which the detent pin  16  is moved out of the receptacle  17  by means of the pretensioned leaf spring  15 . 
       FIG. 9  shows an oblique top view of the receptacle  17  with the detent pin  16  of  FIG. 8  which is locked therein. It is clearer in  FIG. 9  (than in  FIG. 8 ) that pulling on the Bowden cable  13  to the left (in  FIG. 9 ) releases the catch mechanism between the detent pin  22  and the round wire spring  22 , since the round wire spring  14  is pulled to the left out of the groove  22  by means of the pull. 
       FIG. 10  shows two guiding ridges  19 , which are attached to the bottom of the inlet funnel  9  (on the lower edge). With the aid of these guiding ridges  19 , the inlet funnel  9  can be set up so as fasten to the casing  1 , as a result of which an engagement of the four detent pins  16  into the receptacles  17  is facilitated. Instead of the two guiding ridges  19  shown, only one guiding ridge or more than two guiding ridges can naturally also be present. Furthermore, the distance between the guiding ridges  19  can be selected to be greater than that shown in  FIG. 10 . 
       FIG. 11  shows a design sketch of an inventive fastening system  10  in the zero position. In the zero position, all components (e.g. the leaf spring  15 ) are shown without a pretensioning, as a result of which the head  23  of the detent pin is shown as almost passing through the leaf spring  15 . The receptacle or the bearing  17  (counter bearing for the Bowden cable  13 ) is fastened to the actual front casing  1  (not visible in  FIG. 11 ) from the inside, so that the receptacle  17  is not visible from the outside. A fastening of the receptacle  17  to the casing  1  is possible by means of adhesion or screwing for instance. The centering or detent pin  16  is fastened to the inlet funnel  9  from the rear, so that it is likewise not visible from the outside if the inlet funnel  9  is attached to the casing  1 . 
     In the embodiment shown in  FIG. 11 , the leaf spring  15  has a pretension  2  of 3 mm. Since the components illustrated in  FIG. 11  are shown to scale, the dimensions of the other components shown in  FIG. 11  result accordingly by way of the pretension  2  of 3 mm. In the embodiment shown in  FIG. 11 , the round wire spring  14  has no pretension. However, a pretension of 0.5 mm for instance is possible if the detent pin  16  is engaged with the round wire spring  14 . 
       FIG. 12  shows the fastening system  10  shown in  FIG. 11  as a three-dimensional exploded view. 
       FIG. 13  shows the inventive fastening system  10  shown in  FIGS. 11 and 12  from below. A stop of the receptacle  17  is shown with reference character  4 . A movement of the round wire spring  15  as a result of the pull by the Bowden cable  13  is advantageously restricted by means of this stop  4 . This herewith prevents the round wire spring  14  or the receptacle  17  from being destroyed (overstretched) by way of the excessively large tensile force applied to the Bowden cable  13 . 
     The fastening and release of the inlet funnel  9  by means of the inventive snap-fit and securing mechanism  10  comprising the unlocking system to (from) the casing  1  is described again below with the aid of  FIGS. 11 to 13 . 
     The detent pins  16  or more precisely the heads  23  of the detent pins  16  are inserted into a respective hole  3  of the corresponding receptacle  17  in order to fasten the inlet funnel  9  to the casing  1  (i.e. the centering and detent pins  16  are centered in the receptacle  17 ). The tapering head  23  herewith pushes the round wire spring  14  to the side on the one hand and pushes the leaf spring  15  upwards on the other hand. The round wire spring  14  engages in the guide groove  22  of the detent pin  16  if the detent pin  16  is inserted correspondingly far into the receptacle  17 . If the round wire spring  14  engages in the groove  22 , the detent pin  16  is locked to the receptacle  17  and can no longer be pulled out of the receptacle  17  (without actuating the Bowden cable  12 ). 
     To release the inlet funnel  9  from the casing  1 , a service flap (not shown) of the casing  1  is opened, behind which is arranged the unlocking handle  11 . The unlocking handle  11  is completely removed together with the additional Bowden cable  21  and guided and actuated upstream of the inlet funnel  9 . By actuating the unlocking handle  11 , the force, with which the unlocking handle  11  is actuated, is guided to the force distributor  12  by way of the additional Bowden cable  21 . By means of the force distributor  12 , this force is distributed equally onto the Bowden cables  13  and is guided to the receptacles  17  and/or more precisely to the round wire springs  14 . The round wire springs  14  are pulled out of the respective guide groove  22  by actuating the unlocking handle  11 , i.e. the round wire springs  14  snap out of the respective guide groove  22 . As a result of the pretension  2 , which prevails in the leaf springs  15 , the locking pins  16  are pushed out of their mounting and/or receptacle  17 , as a result of which the inlet funnel  9  releases from the casing  1 . The securing leash  18  prevents the inlet funnel  9  from falling onto the floor or onto the feet of an operating person. 
     The afore-described service flap of the magnetic resonance system  20  has screws, by way of which the service flap is opened and/or closed. As it is not only the unlocking handle but instead the electronics system of the magnetic resonance system  20  that can be accessed by way of the service flap, there is a rule in most countries that the service flap is only to be opened using a tool (e.g. a screwdriver). 
     As, in the embodiment shown, the inlet funnel  9  is only attached to the casing  1 , no vibrations are transmitted from the body coil or from the magnetic endspinning to the inlet funnel  9  and thus to the front or rear casing of the magnetic resonance system.