Abstract:
The tank flap of an automobile is locked via a wire spring with which an extension connected to the tank flap will cooperate. A spring-biased locking body keeps the wire spring in the releasing position when the tank flap initially is forced inwards.

Description:
RELATED APPLICATIONS 
   The present application is based on, and claims priority from, German Application Number 10 2004 035013.2, filed Jul. 20, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety. 
   FIELD OF THE INVENTION 
   This invention relates to a locking system for a fuel door housing. 
   BACKGROUND OF TH INVENTION 
   A fuel door housing has become known from DE 203 11 149 U1, for example. It comprises a single-piece cup shaped body which is inserted into a through aperture in the body of a vehicle. The cup shaped body pivotally supports a tank flap which, at its inside, has an arresting shoulder which interacts with a closing element of a closing device. The closing device may be driven via a central power door lock control. The closing device is housed in a separate compartment of the cup shaped body. 
   SUMMARY OF THE INVENTION 
   It is the object of the invention to provide a locking system for a fuel door housing in which the tank flap can be automatically locked by closing it from the opened position, and in which the tank flap is automatically unlocked by applying a pressure thereto while the flap is being swung out through a certain angle and, finally, in which the unlocked position of the locking device is lockable. 
   In the inventive locking system, a locking projection which has a lateral locking recess is arranged at the inside of the tank flap. The locking recess interacts with a spring leg mounted on one side, e.g. a spring wire, on the cup shaped body. The spring leg may be resiliently movable between a locking position and a releasing position. It will engage the locking recess when it is in a locking position. This is the case when the tank flap is in its closed position. The spring leg is mounted in such a way here as to automatically snap into the locking recess when the tank flap is moved to the closed position. 
   Furthermore, the cup shaped body has disposed therein an ejector body which is guided along an axis which points to the same direction as the axis of the locking projection with the ejector body being movable between an outer and an inner position. If the terms “inner” and outer” are spoken of above and below they refer to the position in which the fuel door housing is mounted in the vehicle. The tank flap, when in a closed position, is in the same plane as the adjoining outer surfaces of the automobile body. Therefore, the term “inner” suggest that the part concerned is farther inward with respect to the outer shell of the body. 
   The ejector body is biased by a first biasing spring, namely to the outer position. Therefore, the ejector body attempts to move the locking projection to the outside, but is prevented for a time as long as the spring leg is seated in the locking recess. When the spring leg is moved out of the locking recess the ejector body, while being driven by its biasing spring, will be able to move the locking projection to the outside, thus swinging out the tank flap through a certain angle. 
   To allow the automobile user to easily open the tank flap, the invention further provides an oblique deflection surface in the area of the locking recess by which the spring leg is deflected sidewards when the locking projection is moved inwardly against the first biasing spring. This causes the spring leg to be swung to its releasing position. However, care should be taken to maintain the spring leg in the releasing position because otherwise it would snap back automatically into the locking recess after the locking projection has moved to the outside. Therefore, the invention provides a locking body which is movably supported in the cup shaped body in parallel with the axis of the ejector body between an outer and an inner position and is biased by a second spring against an abutment of the cup shaped body, the direction of bias being from the outside to the inside. The locking body has a lateral shoulder which is disposed between the spring leg and the tank flap when the tank flap is in the closed position. The second biasing spring attempts to move the locking body from the outside to the inside, but is prevented from doing so by the spring leg. However, if the leg is swung out sidewards in the above-described manner it becomes possible to move the locking body via the second biasing spring from the outside to the inside, which causes the lateral shoulder to come to lie at the level of the spring leg. This way holds the spring leg in its releasing position and the ejector body can move the locking projection and, hence, the tank flap outwardly. During this procedure, a driver portion of the ejector body grasps the locking body and again moves it outwardly against the second biasing spring. As a result, the lateral shoulder releases the spring leg again and the spring leg can maintain the lateral shoulder between the spring leg and tank lid in a biased position for a next actuation. 
   If the tank lid is swung back to the completely closed position from the open one the locking projection should be given such a shape that the spring leg readily snaps into the locking recess. However, this deflection of the spring leg is insufficient to release the locking body or its lateral shoulder. This will not happen until the locking projection is forced inwards, swinging the spring leg to such an extent that the lateral shoulder is released and the locking body can be swung inwardly against an inner stop. 
   The inventive locking system needs little constructional space in the fuel door housing and requires a relatively small number of individual components. According to a preferred aspect of the invention, the locking recess is formed by an annular groove and the deflection surface is formed by an oblique wall of the annular groove. The spring leg is a leg of a U-shaped wire spring the two spring legs of which preferably are approximately parallel while they engage the locking recess or annular groove. 
   According to another aspect of the invention, the spring leg or U-shaped wire spring can be attached to the inside of a lid by which the compartment which accommodates the described components of the locking system can be closed from the outside. For a pre-assembly, the locking body is pre-mounted on the lid by arranging the outer shoulder between the spring legs and the lid. The spring accommodated in the locking body is supported on the lid here and urges the extension against the upper side of the spring legs. The remaining components are introduced in the compartment of the cup shaped body that was opened before, and are fixed in an appropriate fashion. 
   If the tank lid is intended to be opened only if the power door locks produce an opening signal a locking mechanism should be provided for the ejector body such as to prevent the ejector body from being forced inwardly against its biasing spring from the tank lid. According to an aspect of the invention, the purpose is served by a locking element which is guided in a guide of the cup shaped body and is actuated by an electric motor via transmission means to shift the locking element to the locking position or unlocking position. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     Embodiments of the invention will be described below with reference to the drawings. 
       FIG. 1  shows how to install an inventive locking system in cup shaped body as viewed in a perspective outline. 
       FIG. 2  shows a representation similar to  FIG. 1 , but with the tank flap unlocked. 
       FIG. 3  shows a perspective view of the locking system of  FIGS. 1 and 2  in a removed condition. 
       FIG. 4  shows a modified embodiment of an inventive locking system. 
       FIG. 5  shows the installation of the locking system of  FIG. 4  in a cup shaped body comparable to the assembly of  FIGS. 1 and 2 . 
       FIG. 6  shows a perspective view of a third embodiment of a locking system according to the invention. 
       FIG. 7  shows a perspective view of a fourth embodiment of a locking system according to the invention. 
       FIG. 8  shows how to install the locking system of  FIG. 7  in a cup shaped body. 
       FIG. 9  shows a perspective view of an underside of a lid for the cup shaped body of the foregoing Figures. 
       FIG. 10  also shows the underside of the lid of  FIG. 9  with the other components of the locking system associated according to  FIG. 7 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In  FIGS. 1 and 2 , a cup shaped body is formed at  10  as it has become known in its fundamental structure from DE 203 11 149, for example. The body is a single-piece body of a plastic material which has an opening at the bottom to introduce a gas filling nozzle. The cup shaped body  10  points to a separate compartment  12  which is severed by lateral walls from the remaining cavity of the cup shaped body. 
   The compartment  12  accommodates a locking system  14  which is shown individually in  FIG. 3 . 
   In  FIG. 3 , a locking projection  16  can be seen which has an outer conical portion  18  and an inner conical portion  20 . If the speech is about “inner” and “outer” it refers to the position with regard to the outer shell of the body of the vehicle that is not illustrated here. As is known the cup shaped body is introduced in an opening of the outer body shell. Therefore, the open side of the compartment  12  that is shown in  FIGS. 1 and 2  faces the outside. 
   An annular groove  22  the upper groove wall  24  of which is configured as an oblique surface is formed between the portions  18 ,  20 . Via the cylindrical portion  18 , the locking projection  16  is connected to the inside of a tank flap which is hinged to the cup shaped body. This is not illustrated. Reference is made here to the German Utility Model which was repeatedly mentioned already. 
   In  FIG. 3 , a U-shaped wire spring  26  can be recognized which has two spring legs  28 ,  29 . As can be appreciated from  FIG. 3  the spring legs  28 ,  29  engage the annular groove  22 . The spring legs  28 ,  29  run approximately in parallel when in this position. The spring legs  28 ,  29 , which are manufactured from a suitable spring wire circular in cross-section, extend to the right across the locking projection  16  in  FIG. 3 . A locking body  30  can be seen there and has an elongate sleeve portion  32  and an upper radial flange  34 . As can be appreciated the flange  34  is located above the spring legs  28 ,  29  which prevent the locking body  30  from being moved downwards. The sleeve-shaped portion  32  has disposed therein a biasing spring  36  which is supported by a portion  38  and extends upwards through an opening  39  in the flange  34 . 
   An ejector body  16  is arranged below the locking projection  16 . It has a sleeve-shaped portion  42  which accommodates a biasing spring  44  which is supported by the bottom (not shown) of the compartment  12  ( FIGS. 1 and 2 ). In its upper area, the ejector body has a radial flange  46  the diameter of which is larger than that of the sleeve portion  42 . The flange  46  has centrally disposed thereon an axial conical extension  48 . Ribs  50 ,  52  are located on opposed sides of the flange  46  at the upper side thereof. An extension  54  is provided as projecting radially from the flange  46 . 
   The U-shaped spring  26  is attached to a lid for the compartment  12 . More reference to this fact will be made below. The sleeve-shaped portion  32  of the locking body  30  is axially guided in a cylindrical guide  56  in the compartment  12 . An appropriate guide in the compartment  12  is also provided for the cylindrical portion or sleeve portion  42  of the ejector body  40 . The radial extension  54  is guided in a guiding slot  58  of a wall  60  in the compartment  12  (also see  FIG. 1  here). 
     FIG. 3  shows the locked position of the tank flap which is not shown. If a pressure is applied to the tank flap from outside to inside the locking projection  16  will move inwardly while carrying along the ejector body  40  against the biasing force of the spring  44 . At this point, the oblique groove surface  24  expands apart the spring legs  28 ,  29 , namely to an extent that allows the radial flange  34  of the locking body  30  to be moved downwards because of the force of its biasing spring  36 . The biasing spring  36  is supported by the above-mentioned lid which closes the compartment  12  towards the outside. This causes the flange  34  to get to the level of the spring legs  28 ,  29 . It is understood that the locking body, while moving inwardly as described, is limited in the compartment  12  via a stop which is not shown. As a result, the flange  34  keeps the spring legs  28 ,  29  expanded and the ejector body  40  is now capable of moving upwards, thus swinging open the tank lid by a certain amount. 
   While the ejector body  40  is moving outwardly as described it finally strikes against the inside of the lid (not shown) that faces it. At this stage, the rib  50  grips under the flange  34  so as to carry along the locking body  30  upwards to the position shown in  FIG. 3  in which the upper surface of the flange  34  bears against the inside of the lid. When the tank lid is closed again the conical portion  12  gets between the spring legs  28 ,  29  again, straddling them apart a little bit, but not to such an extent that the locking body  30  could be moved down. This movement is continued for a time until the spring legs  28 ,  29  snap into the annular groove  22 . 
   The design of the locking system  14  is identical in all embodiments which now follow. This is why reference is no longer made to the locking system. By the way, those components of the locking system  14  which are shown there are given the same reference numbers as the locking system of  FIGS. 1 to 3 . 
   In  FIGS. 1 through 10 , different driving options for locking the ejector body  40  are illustrated. In  FIG. 3 , a locking element  62  can be seen which is movably guided along a bar-shaped guide  62   a . The guide extends in parallel with the axis of the locking body  30  and ejector body  40 . The locking element  62  has a lateral shoulder  64  which grips under the radial extension  54  and flange  46  in  FIG. 3 . Hence, it is impossible to move the ejector body  40  downwards via the locking projection  16 , thus unlocking the tank flap. An electric motor  66  drives a worm gear  68  which cooperates with a stationary worm portion  70 . When the worm gear  68  rotates it causes the locking element  62  of  FIG. 3  to be moved upwards or downwards. Unlocking the ejector body  40  requires that the locking element  62  be displaced downwardly. Such a displacement can be initiated by power door locks of the automobile, for example. Not until the ejector body  40  is released the tank flap can be unlocked as described above. 
   In a variation from  FIG. 3 , the embodiment of  FIG. 4  provides for a Z-shaped locking element  72  which has a locking portion  74  which, when in the locked position, grasps beneath the extension  54  to prevent the ejector body  40  of  FIG. 4  from moving downwards. The other leg of the locking element  72  extends above a transmission gear  76  which has a spiral groove  78 . The portion  75  of the locking element  72  has inserted therein a pin  80  which engages the groove  78 . At that end of the portion  75  which is left-hand in  FIG. 4 , a guiding slot  82  is provided which is engaged by an extended portion  84  of the shaft of the electric motor  66 . Depending on the sense of rotation of the electric motor  66 , the locking element  72  is radially moved towards the ejector body  40  or away therefrom because the pin  80  has engaged the groove  78 . The embodiment of  FIG. 6  differs from that of  FIGS. 4 and 5  in that the transmission gear  76  is not seated on the shaft of the electric motor  66 , but is driven by a pinion  86  which interengages with teeth on the outer circumference of the transmission gear  76 . The transmission disk  76  is rotatably supported by an axle  88  which engages the slot  82  of the portion  75  of the locking element  72 . This creates a guide for the movement of the locking element  72 . The advantage of the embodiment of  FIG. 6  over that of  FIG. 4  is that the spiral groove  78  may have a pitch which is significantly larger than that of the groove  78  because a gear ratio reduction takes place for the rotation of the electric motor  66 . 
   As ensues from  FIG. 5 , the installation of the electric motor and locking element  72  in the compartment  12  is equal to the installation of the embodiment of  FIG. 4 .  FIG. 5  allows to deduce that a radial movement of the locking element  72  is guided in a slot  90  inside the compartment  72  that is formed in a respective wall. In the embodiment of  FIGS. 1 through 3 , the locking element  62  is guided by the wall  90 . It is understood that the guide for the locking element of  FIGS. 4 and 6  may also be configured in a different manner in the compartment  12 . 
   While the axis of rotation of the electric motor  66  extends in parallel with the axes of the locking body  30  and ejector body  40  in the previously described Figures the axis of the electric motor  66  of  FIG. 7  extends transversely thereto. A frame-like locking element  92  is located above the electric motor  66 , which drives a transmission gear  94  which has a screw thread at its circumference. At its lower side which is right-hand in  FIG. 7 , the locking element  92  has a transmission portion  96  of a complementary thread configuration. Therefore, when the transmission gear  94  rotates the locking element  92  is moved towards the ejector body  40  or away therefrom. As a continuation of the transmission portion  96 , a locking portion  98  is formed at the right-hand side of the locking element  92  and grips under the radial extension  54  of the flange  46  or the flange to selectively lock or release the ejector body  40 . 
   In  FIG. 9 , a lid  100  is shown which closes the compartment  12  of the cup shaped body  10  towards the top. The underside of the lid  100  can be recognized in  FIGS. 9 and 10 . In the area which is left-hand in  FIGS. 9 and 10 , four legs  102  are formed thereto which when the lid is placed on top of the compartment  12  project into the compartment, which fact is outlined in  FIG. 8 . Their purpose is to guide the locking element  92  here. What can be seen particularly in  FIG. 9  is that the U-shaped wire spring  26  is located on the lid  9 , i.e. by means of hook-shaped portions  104 ,  106  which are arranged in pairs and grip over the legs  28 ,  29 , but allow to expand apart the legs  28 ,  29 . In  FIG. 9 , the locking body  30  is located at the underside of the lid  100 , namely between the legs  28 ,  29  on one side of the flange  34  and by a surface of the lid  100  on the other side. Thus,  FIG. 9  shows a pre-mounted assembly which is placed on top of the compartment  12  after the remaining components are built into the compartment.  FIG. 10  shows the entire assembly below the lid  100  with no compartment  12  of  FIG. 8 . 
   The lid  100  has a circular hole  110  through which the cylindrical portion  18  of the locking projection  16  extends for a connection to the tank flap, which is not shown. The opening may be circumferentially provided with an annular gasket which provides a seal between the locking projection  16  and the opening  110 . When the ejector body  40  is shifted upwards while the tank flap is opened the flange  46  comes to rest against the underside of the lid  100  and the conical extension  48  engages the opening  110  where it interacts with the gasket mounted there to establish a seal also in this condition. The seal mentioned is not shown in  FIG. 9 .