Abstract:
The invention relates to a closure for a refueling tank of a motor vehicle. Said closure has a closure cap which can be fixed to a filler neck in a liquid and gas-tight manner. The upper cap part rests against the pipe surface of the filler neck via an annular seating surface equipped with a flat packing. The entry part axially protrudes from the cap part and can be fixed to the filler neck in an axial direction. The aim of the invention is to provide a simple structure, in terms of movement, for reliably achieving an axial connection between the cap part of such a closure and the filler neck. To this end, the entry part is provided with a contacting element which can be reciprocated in relation to an under cut or counter-profile of the filler neck.

Description:
TECHNICAL FIELD 
     The present invention relates to a closure for a fuel tank of a motor vehicle having a closure cap fastenable in a liquid-tight or gas-tight manner to a filler pipe. The closure cap has an upper part being in contact with a seating surface of the filter pipe via an annular seating surface fitted with a flat seal and having on the cap part an axially projecting insertion part that is fastenable in an axially direction on the filler pipe. 
     BACKGROUND OF THE INVENTION 
     Known closures for fuel tanks of motor vehicles are connected with the filler pipe by means of either a screw or bayonet connection, by executing an inserting and rotating motion. Such closure motions are relatively awkward and complicated for automatic refueling systems to perform. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a closure of the type mentioned above for a fuel tank of a motor vehicle, wherein the closure cap is axially fastenable on the filler pipe by executing a simpler movement. 
     To achieve this object a closure of the above mentioned type for a fuel tank on a motor vehicle is provided according to which the insertion part is provided with a contacting element that can be moved back and forth relative to an undercut or counter-profile in the filler pipe. 
     By virtue of the measures according to the present invention, the fastening movement of the contacting element in the filler pipe is derived from the motion of inserting the insertion part into the filler pipe. As a result, a robot, for example, needs only to execute a simple movement in order to insert and fasten the closure cap in the filler pipe, or to detach and remove it from the filler pipe. 
     In a first preferred embodiment of the present invention, the contacting element is pivotally attached to the insertion point. In a further embodiment, provision is made for the contacting element to be a leg spring whose pivoting motion is derived from the axial motion of a sliding element. In other words, the motion of inserting the insertion part tensions the leg spring in such a manner that one of its legs is in contact against a lower edge of the filler pipe while its other leg is in contact against the outside of the plunger. In this way, the cap part, which is rigidly linked with the pivoting axis of the leg spring, is actively forced downwards and against the seating surface of the filler pipe. The axial excursion of the plunger out of the insertion part takes with it the second leg of the leg spring and thus causes the leg spring to pivot, thereby detaching itself from the filler pipe. Since the leg spring is then located within the insertion part, the entire closure cap can be removed from the filler pipe. 
     In accordance with a second and third embodiment of the present invention, the contacting element is radially movable and, according to, the arrangement whereby the contacting element is made up of radially movable bolts or a radially displaceable sealing ring, or also two thereof arranged one above the other, are provided. Preferred variants and embodiments in this respect are found in that the radial bolts are in contact with a lower edge of the filler pipe, or in that the sealing ring projects radially into a circumferential channel. 
     The movement of the radial bolt or sealing ring is obtained when the insertion part is made up of several elements and that the radial movement of the bolt or sealing ring is brought about by a radial relative movement between the individual elements of the insertion part or in that the radial movement of the bolt or sealing ring is brought about by a relative movement between the cap part and the insertion part, or in that, at its end, the insertion part is fitted with a sealing ring that is in radial contact with an area of the inner wall of the filler pipe, or in that the relative movement between the cap part and the insertion part and/or between the individual elements of the insertion part is brought about by means of a lever preferably a rocker lever or eccentric lever, or in that the relative movement between the cap part and the insertion part and/or between the individual elements of the insertion part is achieved by a rotating driving motion, or in that one element of the movement mechanism is connected to an individual element of the insertion part and the other element of the movement mechanism is rotatably or pivotably attached to the other element and abuts against the cap part. 
     The features whereby the circumferential edge of the cap part is arranged within a establishing edge of the filler pipe, the stabilizing edge surrounding and projecting above the seating surface of the filler pipe provided greater security to the extent that, in the event of a crash occurring ill this area of the motor vehicle, the closure cap is protected by the stabilizing edge of the filler pipe, so that in this case the cap is prevented from becoming detached. 
     In order to further simplify operation in those vehicles whose filler pipe is additionally covered over by a flap in the bodywork, which is almost always the case, a closure cap movably connected with the flap are preferably provided. By this means, when the flap is opened or closed fi-om outside, the closure cap can also be brought into the closed position in the filler pipe, or it can be removed again from the pipe. This can be accomplished in a wide variety of ways, for example by an electrical, pneumatic or similar connection. In accordance with an arrangement whereby the closure cap is connected with the flap, a mechanical connection in the form of a lever linkage is provided. In order also to guarantee safety in a crash, the lever linkage possessing a predetermined breaking point is provided. By this means, the flap becomes detached from the closure cap if there is any deformation of the bodywork in this area, so that the cap remains attached to the filler pipe. 
     According to a further preferred embodiment, the movement of the contacting element relative to the undercut or counter-profile of the filler pipe is taken from a thermochemical metal hydride actuator or from a thermal expansion element actuator. This additionally means that the insertion part can be fastened in or detached fi-om the filler pipe in a simple manner via a remote-controlled locking and unlocking system. In other words, in order to unlock or detach the insertion part from the filler pipe, the metal hydride actuator or the expansion-type actuator is thermally activated so that the closure can be removed by the robot, then following refueling and reinsertion of the insertion part in the filler pipe it can again be thermally deactivated, as a result of which a locking action takes place. 
     The thermal activation can be advantageously accomplished electrically via a thermal resistor, so that this procedure can be very simply initiated from inside the vehicle by operating a switch, or from any desired position by means of remote control. 
     The contacting element and the way in which it is moved can take many forms. For example, the movement and sealing action of the contacting element or its radially movable bolt can be configured according to the features whereby the bolts are connected with each other by an articulated lever arrangement which is moved by an actuator, or whereby the articulated lever arrangement on the side facing away from the actuator is acted on by a pressure spring, or whereby the bolts are acted on radially at their inner surfaces, and via an inclined arrangement of sliding surfaces by an axially movable positioning element driven by an actuator, or whereby the bolts are acted on at both sides by the oppositely inclined arrangements of sliding surfaces. 
     The way in which movement is imparted to one or more of the sealing rings of the contacting element and the arrangement of such ring or rings can be configured in that the sealing ring is mounted between the insertion part and the cap part which is axially movable relative thereto, and that between the cap part and the insertion part there is provided the actuator, and/or, in that an annular element is mounted between the cap part and the insertion part, and between this annular element and the cap part on the one hand and between the annular element and the insert part on the other hand, with a sealing ring arranged in each case. 
    
    
     Further details of the present invention may be taken fi-om the following description in which the present invention is described and explained in more detail on the basis of the embodiments depicted in the drawing. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A and 1B show a closure for a fuel tank of a motor vehicle according to a first embodiment of the present invention, in two different positions; 
     FIGS. 2A and 2B are illustrations similar to those in FIGS. 1A and 1B, however they are drawn to a larger scale and depict a second embodiment of the present invention; 
     FIGS. 2C,  2 D and  2 E show a variant of the second embodiment depicted in FIGS. 2A and 2B, including a top view according to the arrows IIE in FIG. 2D; 
     FIGS. 3A and 3B are illustrations corresponding to FIGS. 1A and 1B but depict a third embodiment of the present invention; 
     FIGS. 4A and 4B are illustrations corresponding to FIGS. 1A and 1B but depict a fifth embodiment of the present invention; 
     FIGS. 6A and 6B depict a closure for a fuel tank of a motor vehicle according to a sixth embodiment of the present invention, in two different positions; 
     FIGS. 7A,  7 B and  7 C are in each case similar to FIG. 6A, but show incomplete or different positions, as well as a top view of the contacting and locking element according to a seventh and eighth embodiment of the present invention; and 
     FIGS. 8A and 8B are illustrations similar to FIGS. 6A and 6B, but depict a ninth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The closure  10 ,  110 ,  210 ,  310 ,  410 ,  510 ,  610  or  710  for a fuel tank of a motor vehicle, of which several embodiments are shown in the drawing, is designed in particular for automatic refueling operations, for which purpose a simplified sequence of motions when inserting a substantially cylindrical closure cap  11 ,  111 ,  211 ,  311 ,  411 ,  511 ,  611  or  711  into or removing it from the filler pipe  12 ,  112 ,  212 ,  312 ,  412 ,  512 ,  612  or  712  of the fuel tank, and for obtaining a liquid-tight, gas-tight and crash-proof seal with the filler pipe and for detaching the closure cap again fi-om the filler pipe, is achieved and guaranteed. This simplified closing and opening motion is reduced to a substantially purely translational motion of the closure cap into or out of the filler pipe In a preferred manner, to further simplify automatic refueling, a movement link  14 ,  514 ,  617  or  714  is provided between the closure cap  11 ,  111 ,  211 ,  311 ,  411 ,  511 ,  611  and  711  and a flap  13 ,  113 ,  213 ,  313 ,  413 ,  513 ,  613  or  713  forming part of the bodywork of the motor vehicle, and the translational motion of the closure cap is derived fi-om the pivoting motion of this flap. As shown in simplified form in the drawing, this link may be a mechanical connection  14 ,  514 ,  617  or  717 , but it may also take the form of an electric-motor driven or pneumatic, or similar connection. 
     In accordance with FIGS. 1A and 1B, the closure cap  11  of the closure  10  possesses a flat cap part  16  which is rigidly connected to an insertion part  17  of smaller diameter. On its underside, the cap part  16  possesses an annular groove  18  in which the upper, flanged edge of the insertion part  17  is firmly held, for example clamped, and at this flanged edge  19  is fitted a flat sealing ring  21 , with which the closure cap  11  rests tightly on a seating surface  22  of the filler pipe  12 . In the housing-like cylindrical insertion part  17 , whose front end is of conical configuration, there is pivotally mounted a contacting and locking element  20 , here in the form of four leg springs  23  arranged in pairs diagonally opposite each other. The leg springs  23  are pivotably mounted on pins  26  rigidly fixed on the insertion part  17 , in such a manner that their first leg  24  is oriented towards the inside of the insertion part  17  and their second leg  25  passes through or lies within a lateral, axial slot  27 . 
     The closure cap  11  in addition possesses a plunger  28  that can be moved axially through the cap part  16  within the insertion part  17 . The plunger  28  passes through a central borehole  29  in the cap part  16 , against which latter part the plunger  28  is sealed by an inner sealing ring  31 . At its front end, which is arranged within the insertion part  17 , the plunger  28  possesses a circumferential groove  32  which opens conically towards the outer periphery of the plunger  28  and into which the first leg  24  of the leg spring  23  can enter. 
     At its other end, located outside the insertion part  17 , the plunger  28  is connected to one end of a mechanical coupling  14 , shown here merely in diagrammatic form, and the other end of this coupling is pivotably linked to the flap  13 . The mechanical coupling  14  is provided with a predetermined breaking point  33  which, in the event of a crash, separates the connection between the plunger  28  and thus also the closure cap  11  and the flap  13 . In this embodiment, the filler pipe  12  is provided with a stabilizing edge  34  concentrically surrounding its seating surface  22  and extending at least as high as the outer plane of the cap part  16 , so that in the event of a crash the closure cap  11  is protected. 
     The insertion of the closure cap  11  into or its removal from the filler pipe  12  proceeds as follows: FIG. 1A shows the cap in its closed or sealed position in which the plunger  28  has been completely pushed into the insertion part  17  and the second legs  25  of the leg springs  23  of the contacting and locking element  20  are in pretensioned contact with the outer periphery of the plunger  28 , above the circumferential groove  32 , and the first legs  24  of the springs are in pretensioned contact with the lower annular edge  30  of the seating surface  22 . This causes the insertion part  17  to be pulled downwards via the leg springs  23 , so that the flat sealing ring  21  of the closure cap is actively pressed against the seating surface  22  of the filler pipe. This active contact is maintained if, for example, the predetermined breaking point  33  of the mechanical coupling  14  is separated in a crash. The closure cap  11  is detached from the filler pipe  12  by opening the flap  13  or by correspondingly pulling out the closure cap  11  by hand, so that, as shown in FIG. 1B, the second legs  25  of the leg springs  23  move into the area of the circumferential groove  32  and, because of their pretension, engage in the circumferential groove  32 , so that the leg springs  23  pivot relative to each other, as indicated by the arrows A and A′, and thus the first legs  24  of the springs disengage from the filler pipe  12  and move into the slots  27 . Following this detaching step, the closure cap  11  can be withdrawn in a further step from the filler pipe  12 , because the lower conical end of the plunger  28  comes up against the pivot pins  26  or the leg springs  23  and thus makes positive connection with the insertion part  17 . 
     During the insertion motion of the closure cap  11  into the filler pipe  12 , and after the cap part  16  comes to rest against the filler pipe  12 , the plunger  28  continues to be moved axially inside the insertion part  17  so that, because of the engagement of the second legs  25  of the leg springs in the circumferential groove  32 , the leg springs  23  pivot back again in the opposite direction and assume the position shown in FIG.  1 A. 
     In the closure  110  illustrated in FIGS. 2A and 2B, the insertion part  117  of the closure cap  111  is made up of several elements and is movable relative to the cap part  116 . In the cap part  116  the flat sealing ring  121  is positioned directly in the annular groove  118  on the underside of the cap. The cap part  116  is provided with a central opening for a tab  136  which is rigidly connected to a bell-shaped element  137  of the insertion part  117 . To the tab  136  is pivotably attached a rocker lever  138  which rests on the cap part  116  and which, when it is moved in the direction indicated by the double arrow B, causes the bell-shaped element  137  of the insertion part  117  to move axially. Between the bell-shaped element  137  and the cap part  116  there is arranged a contacting and locking element  120  having the form of radially movable segments  139  uniformly distributed around the circumference, as well as an annular pressure element  141 . The segments  139  are guided on the one hand by the annular pressure element  141  and on the other hand by the cap part  116 . At their upper end facing the cap part  116 , the segments  139 , which are encircled in a peripheral area by an O-ring  142 , possess a nose  143  by means of which they can engage under the annular edge  130  of the filler pipe  112  when the closure cap  111  is in the closed position (FIG.  2 A). Opposite the annular pressure element  141 , the bell-shaped element  137  is provided with a sealing ring  144  on which the pressure element  141  acts in order to achieve a sealing effect. In the area of the segments  139 , the bell-shaped element  137  is provided with a curved surface  146  against which the inner ends of the segments  139  are in contact and via which the segments  139  are moved radially when the bell-shaped element  137  is moved relative to the segments  139  and to the pressure element  141 . 
     Proceeding from FIG. 2B, which depicts the position in which the closure cap  111  can be withdrawn from the filler pipe  112 , the rocker lever  138  is moved in the direction of the arrow B thus causing an upwards movement of the bell-shaped element  138  relative to the cap part  116 . This upwards movement causes the segments  139  to move radially so that they engage beneath the annular edge  130  of the filler pipe  112 , and furthermore the sealing ring  144  is compressed between the lower annular edge of the bell-shaped element  137  and the pressure element  141  so that a sealing effect is obtained against the inner circumferential surface of an inner skirt  145  of the filler pipe  112 . In addition, although this is not shown in detail here, the positive connection between segments  139  and filler pipe  112  brings about a sealing effect of the O-ring  142  against the upper inner area of the skirt  145  of the filler pipe  112 . FIGS. 2A and 2B depict (left and right) two variants of the design of the skirt  145  of the filler pipe  112  in this area below the seating surface  122  of the pipe. 
     It is understood that the closure cap  11  is detached from within the filler pipe  112  in appropriate reverse order, i.e. by moving the rocking lever  138  back. Even if the flap is not shown, it is understood that this movement of the rocker lever  138  can also be made to depend on the opening or closing of the flap. 
     FIGS. 2C, D and E depict a variant of the closure  110  shown in FIGS. 2A and 2B. This closure  110 ′ differs from closure  110  substantially in that a further number of radially movable segments  139 ′ of the contacting element  120  are arranged beneath the radially movable segments  139 , and the annular pressure element  141 ′ is arranged beneath the second movable segments  139 ′ and an annular guide  140 ′ is arranged between the first movable segments  139  and the second movable segments  139 ′. The radial movement of these second segments  139 ′ towards the skirt  245  of the filler pipe is also derived, via appropriate curved surfaces  146 ′, from the axial motion of the bell-shaped element  137 ′ of the insertion part  117 ′, said element being longer than the bell-shaped element  137  of the preceding variant. Since these second radially movable segments  139 ′ also engage beneath an annular edge  130 ′ arranged on the filler pipe  112 ′ (FIG.  2 C), an additional positive connection is obtained. 
     FIGS. 2C, D and E also exhibit a mechanical lever connection  133 ′ between the closure cap  111 ′ and flap  112 ′. 
     The closure  210  shown in FIGS. 3A and 3B differs from the closure  110  depicted in FIGS. 2A and 2B in that the segments  139  of the contacting element  120  are replaced by an appropriately configured sealing ring  250  of a contacting element  223 , and both the bell-shaped element  237  of the insertion part  217  as well as the pressure element  241  are differently configured. In the embodiment illustrated, the edge of the cap part  216  is similar to that of cap part  116 , but in the centre it is provided with a recess, the bottom of which is provided with a slot through which passes the tab  236  to which an eccentric lever  238  is pivotably attached. The recess is deep enough for both the tab  236  and the rocker lever  238  to be located within or below the upper surface of the cap part  216 . When relative motion occurs between the cap part  216  and the pressure element  241  and the here almost cylindirical element  237 , both the sealing ring  244  as well as the sealing ring  250  are axially acted upon, and the upper sealing ring  250  like the sealing ring  244  forms a seal against the inner circumference of the filler pipe  212 , but in addition, the radially expanding area of the ring caused by the axial compression positively engages in a channel  251  in the skirt  245  of the filler pipe  212 . In this way, similar to the case in the preceding embodiments, an axially firm or positive connection is achieved between the closure cap  211  and the filler pipe  212 . 
     The movement sequences during the closing and opening, or between the insertion and withdrawal of the closure cap  211  into or from the filler pipe  212 , are accomplished in the manner described above. Here, also, it is understood that the necessary pivoting movement of the eccentric lever  238  can be executed either manually or, as indicated, via a mechanical coupling  214  with the flap  213 . 
     In the closure  310  depicted in FIGS. 4A and 4B the relative motion between the individual elements themselves of the insertion part  317  and between these elements and the cap part  316  is accomplished by means of a type of spindle drive  335 . For this purpose, the element  337  of the insertion part  317  is provided with an externally threaded bolt  336  over which an internally threaded sleeve  338  engages, said sleeve being electrically or pneumatically driven and taking its rotational motion, for example, from the opening motion of the flap  313 . As shown in these Figures, the output drive shaft  353  of an electric motor  354  pivotably attached to the flap  313  is connected in a rotationally rigid and axially movable manner with the internally threaded sleeve  338 . The closure cap  311  is connected with the flap  313  via a rigid bellows  355  or a stable spring suspension in order to permit axial motion. Otherwise, the element  337  and the pressure element  341  of the insertion part  317  and the cap part  316  of the closure cap  311  have almost the indentical configuration to that found in the embodiment illustrated in FIGS. 3A and 3B. The same is true of the filler pipe  312 , which is provided with the skirt  345  and with an appropriate channel  351 . 
     The embodiment of a closure  410  illustrated in FIGS. 5A and 5B differs from the embodiment shown in FIGS. 3A and 3B in that, firstly, instead of the eccentric lever a rocker lever  438 , and instead of annular seals of square or round cross section an annular seal of strip-like, longitudinally rectangular cross section is provided. As seen in FIG. 5A, in the closed position the strip-shaped annular seal  444  and  450  bulges radially outwards. This also results in a positive connection between these sealing rings  444 ,  450  and the channel  451  incorporated into the skirt  345  of the filler pipe  412 . 
     In the embodiments illustrated in FIGS. 6A to  8 , as in the embodiments shown in FIGS. 2 to  5 , provision is made for the simplified closing and opening movement to be reduced to a substantially purely translational movement of the closure cap and to a radial movement of a contacting and locking element  520 ,  620  or  720  arranged in the closure cap  511 ,  611  or  711 . The radial movement of the contacting and locking element  520 ,  620  or  720  is, however, taken from the preferably axial movement of an actuator  515 ,  615  or  715  in the form either of a thermochemical metal hydride actuator or in the form of a thermal expansion element. The thermal actuator  515 ,  615  or  715  is connected to an electrical thermal resistor, which can be switched on or electrically energized by operating a switch located inside the motor vehicle or by remote control, in order to activate the actuator. For the movement connection  514 ,  614  or  714  between the closure cap  511 ,  611  or  711  and the [flap] a servomotor can be operated to open the flap  513 ,  613  or  713 , for example with a delay, by electrically activating the actuator  515 ,  615  or  715 . Correspondingly, the return movement of the flap by means of the servomotor is followed, at a staggered interval, by the deactivation of the actuator once the closure cap has been introduced into the filler pipe. 
     As shown in FIGS. 6A and 6B, the closure cap  511  of the closure  510  possesses a flat cap part  516  which is rigidly attached to an insertion part  517  of smaller diameter. The cap part  516  is provided on its underside with a concave annular groove  518  in which is positioned a sealing ring  521 , with which the closure cap  511 , in the closed position, is in sealing contact with the seating surface  522  of the filler pipe  512 , as shown in FIG.  6 A. The seating surface  522  is part of an inward flanged edge of the filler pipe  512 . 
     The insertion part  517 , which is mounted suspended by means of detent elements  556  on the underside of cap part  516 , possesses two or more radial openings  557  distributed over the periphery in which there are arranged radially movable contacting and locking elements  520  each in the form of a locking slide  558 . The radial outer ends of the locking slides  558  possess an inclined surface  559  with which, when the closure  510  is in the closed position, they engage beneath a lower bent annular edge  530  of the seating surface  522  of the filler pipe (FIG.  6 A). At their radial inner ends, the two locking slides  558  are connected to an articulated lever arrangement  560 , the levers  561  and  562  of which are articulatedly connected on the one hand with the respective locking slide  558 , and on the other hand with each other. One end of a pressure spring  564  is supported at the articulated Joint  563  of the two levers  561  and  562 , which are of equal length, while the other end of the spring is in contact with the underside of the cap part  516 . Between the articulated joint  563  and the bottom  565  of the insertion part  517 , and facing away from the pressure spring  564 , there is located the thermal actuator  515  having an axial plunger  566  which can exert pressure against the articulated joint  563  counter to the pressure spring  564 . 
     The thermal actuator  515  is capable of converting thermal energy directly into potential energy and it takes the form either of a thermochemical metal hydride actuator or of a thermal expansion element (containing for example wax). This thermal actuator  515  is activated by applying electric current to a thermal resistor which is thermally coupled, in a manner not shown, to the thermal actuator  515 . 
     The movement link between the flap  513  and the cap part  516  is provided in the form of a merely diagrammatically depicted mechanical coupling  514 , which is pivotably connected on the outside to the cap part  516  and on the inside to the flap  513 . A coupling element possesses a predetermined breaking point  533  which separates the connection between the closure cap  511  and the flap  513  in the event of a crash. In a manner not depicted here, the flap  513  may be opened and closed with the aid, for example, of a servomotor. 
     The procedure of locking the closure cap  511  or its insertion part  517  to and detaching it from the filler pipe  512  is as follows: 
     FIG. 6A depicts the closed or sealed position in which the insertion part  517  of the closure cap  511  is located inside the filler pipe  512  and is locked to it, fixed against axial movement, and also in this position the cap part  516  of the closure cap  511  is in sealing contact with the seating surface  522  of the filler pipe  512 . In this closed position the thermal actuator  515  is in its retracted, deactivated position. If the filler pipe  512  needs to be opened to permit automatic refuelling of the vehicle, the thermal actuator  515  is activated, by means of a switch inside the vehicle or by remote control, in such a manner that voltage or current is applied to the thermal resistor—not depicted—so that the thermal resistor heats up and gives off its heat to the thermal actuator  515 , thus causing plunger  566  thereof to move axially. The positioning force of the thermal actuator  515  overcomes the pressure force of the pressure spring  564  so that, as shown in FIG. 6B, the articulated lever arrangement  560  is displaced against the action of the pressure spring  564 , thereby causing the locking slides  558  to move radially inwards and as a result to disengage from the lower annular edge  530  of the seating surface  522 . The closure cap  511  is now detached or free from filler pipe  512 . Through the mechanical movement link  514 , the closure cap  511  can be lifted out of and away from the filler pipe  512  by pivoting the flap  513  so that the filler pipe  512  is freely accessible for automatic robot refuelling (or also for manual refuelling). The locking closing of the filler pipe  512  by means of the closure cap  511  takes place in the reverse order, i.e. when the flap  513  is closed, the closure cap  511  is moved onto and into the filler pipe  512 . Once this process of inserting the cap is completed, the thermal actuator  515  is again deactivated, so that as the metal hydride actuator or the expansion element cools down, it gradually loses its positioning force, so that the pressure spring  564  is able to return the articulated lever arrangement  560  and thus the locking slides  558  to their position as shown in FIG.  6 A. 
     FIG. 7A shows a configuration of the closure cap  611  that is similar to the design of the closure cap shown in FIGS. 6A and 6B. In this embodiment as well, the cap part  616  and the insertion part  617  are rigidly connected with one another, and in the insertion part  617  or between the insertion part  617  and the cap part  616  there are provided radial openings  657  in which radial locking slides  658  are radially movable and engage with their inclined surfaces  659  beneath the annular edge  630  of the seating surface  622  of the filler pipe. The way in which the radial motion of the locking slides  658  is activated differs from the preceding embodiment. For this purpose, at their radial inner surfaces the locking slides  658  possess sliding surfaces  669  and  672  running at an inclined angle both upwards and downwards and interacting with corresponding sliding surfaces  668  and  671  of an axially movable first positioning element  667  or a second positioning element  670 . At one of its ends, the upper positioning element  667  is acted on by the thermal actuator  615  and at its other end it is rigidly connected to the second positioning element  670 . 
     The locking and unlocking of the closure cap  611  inside the filler pipe  512  is also accomplished by activating and deactivating the thermal actuator  615  in such a way that, in this case, when deactivation occurs, the locking slides  658  disengage from the seating surface  622  of the filler pipe, whereas when the thermal actuator  615  is activated, locking as shown in FIG. 7A takes place. It is understood that when the thermal actuator  615  is arranged between the second positioning element  670  and the bottom  665  of the insertion part  617 , or when the pairs of sliding surfaces  668 ,  669  and  671 ,  672  are inclined in the other direction (upwards in FIG.  7 A), the thermal actuator  615  must be deactivated in order to detach the insertion part  617 , and for the locking position of the closure cap  611  in the filler pipe  612 . 
     FIGS. 7B and 7C illustrate a closure cap  611 ′ of this type. In this case, the contacting and locking element  620 ′ possesses four locking slides  658 ′ uniformly distributed around the periphery, said slides being preferably inclined at an angle of about 30° towards the longitudinal centre axis of the closure  610 ′ and they are guided on a lower positioning element  670 ′. For this purpose, the locking slides  658 ′ and the lower positioning element  670 ′ possess contiguous grooved or spring-loaded sliding surfaces  671 ′ or  672 ′. The thermal actuator  615 ′ is located on the one hand on the upper surface of the lower positioning element  670 ′ and on the other hand is supported against the cap part  616 ′, in a manner not depicted in detail here. The insertion part  617 ′, which is of one-piece construction with the cap part  616 ′, possesses radial slots  657 ′ through which the nose-like ends  659 ′ of the locking slides  658 ′ project. 
     The left side of FIG. 7B shows the locking position of the locking slides  658 ′ beneath the annular edge  630 ′ of the filler pipe  612 ′ with the thermal actuator  615 ′ deactivated. If the thermal actuator  615 ′ is activated, the lower positioning element  670 ′ is moved downwards as shown in the right half of FIG. 7B, and as a result the locking slides  658 ′ move downwards and inwards and conseqently their nose-shaped ends  659 ′ disengage from the lower edge  630 ′ of the filler pipe. This sliding motion is supported by a lower inclined sliding surface on the slots  657 ′. The closure cap  611 ′ can thus, as described for the other embodiments, be removed from the filler pipe  612 ′. When the thermal actuator  615 ′ is deactivated, the lower positioning element  670 ′ moves upwards, said movement being possibly supported or also executed by means of a pressure spring not depicted here. 
     In the embodiment of the closure  710  illustrated in FIGS. 8A and 8B, the cap part  716  provided on its underside with a flat sealing ring  621  which, in the closed position, is in contact with the concavely curved seating surface  622  of the filler pipe (FIG.  8 A). The filler pipe is shaped in such a way that a tapering skirt element  645 , which accepts the insertion part  617 , is formed as an extension of the seating surface  622  of the filler pipe and is provided here with, for example, two axially spaced annular channels  751 . 
     In this embodiment, the cap part  716  and the insertion part  717  are guided in axial motion in relation to each other. An annular element  755  is guided in axial motion between the cap part  716  and the insertion part  717 . Between the cap part  716  and the annular element  775  on the one hand, and the annular element  775  and the insertion part  717  on the other hand, there is respectively provided an annular seal  744  or  750 . The annular seals  744  and  750  are designed and arranged in such a manner that when the closure cap parts  716 ,  775  and  717  undergo axial motion the annular seals between them expand in a radial direction and can enter into the annular channels  751 ,  752  to form a sealing and axially locking engagement. 
     The thermal actuator  715  is located between the bottom  765  of the insertion part  717  and an intermediate bottom element  776  of the cap part  716 , which is something that can also be done in the embodiment shown in FIG.  7 . 
     In order to open the closure  710 , starting from the closed position shown in FIG. 8A, the thermal actuator  715  is activated as described above, and because of the resulting positioning forces and the travel distance the cap part  716  and the insertion part  717  are caused to move relative to each other, i.e. apart. More accurately expressed, the insertion part  717  is moved axially away from the cap part  716 . This releases the axial pressure on the sealing rings  744 ,  750 , so that these sealing rings move radially back and out of the respective annular channel  751 ,  752  in the skirt  745  of the filler pipe  712 . With the ring seals  744  and  750  in this position (FIG.  8 B), the closure cap  711  can be withdrawn and removed from the filler pipe  712 . 
     This occurs in the manner described for FIGS. 6A,  6 B. During this process, and while the vehicle&#39;s tank is being refuelled either automatically or by hand, the thermal actuator  715 —it should be mentioned once more—remains activated. The closing and locking of the closure cap  711  in the filler pipe  712  occurs in the appropriate reverse order: Once the closure cap  711  has been inserted into the filler pipe  712 , the thermal actuator  715  is deactivated so that, due to the cooling of the thermal actuating element the positioning forces act in the opposite direction. As a result, because the fixed end of the thermal actuator  715  is firmly attached to the bottom  776  of the cap part  716  and also the movable positioning plunger of the actuator is firmly attached to the bottom  765  of the insertion part  717 , the insertion part  717  is retracted in the direction of the cap part  716 , thereby compressing the sealing rings  744 ,  750  and moving them radially into the annular channels  751 ,  752  to achieve locking. In this embodiment as well, at a predetermined time interval, the activation of the thermal actuator  715  can be followed by the movement of the flap  713  connected to the closure cap  711 , and the aforementioned movement of the flap  713  can be followed by the deactivation of the thermal actuator  715 .