Patent Abstract:
The invention concerns a level limit valve for the fuel tank of a vehicle. Such valves serve the purpose, that upon the filling of the fuel tank, the filled quantity of the fuel is limited. The proposed level limit valve possesses a valve body  1  which can be positioned within the fuel tank at the end of a filling pipe. The valve body is equipped with an intake port  22  which is connectable with the said filling pipe and an outlet port  21  emptying into the interior of the fuel tank. Further, in the valve body  1  is found a flap  4 , which is pivotally movable between a position tightly sealing the outlet port  21  and a position wherein this is opened. The float  3  is movably connected to said flap  4  by means of a lever rod  5 . The lever rod  5  penetrates the outlet port  21  at least in the opened position of the flap  4  and is connected by means of linkage with that outer side  28  of the flap  4  which is proximal to the outlet port  21.

Full Description:
FIELD OF INVENTION 
   The invention concerns a level limit valve for the fuel tank of a motor vehicle. Such a valve is placed within the tank at the end of the intake pipe, which serves for the filling of the tank. Upon the attainment of a specified level of fuel, the valve is designed to close the intake pipe. When the intake pipe is thus closed, the fuel rises therein and triggers the feed nozzle to shut off. The closure of the intake pipe is assured by means of a pivoted flap shut-off in the valve body. This pivoted flap is coupled with a movable float on the valve body. At a low level of fuel in the tank, the flap opens, so that the fuel, through valve intake and outlet ports, can again enter the tank. Toward the end of the filling process, the said float rises and moves the valve flap into its closed position, in which the flap seals the exit port. 
   BACKGROUND OF INVENTION 
   In the case of conventional valves, the flap is supported with a pivoting axle in the valve body, which extends outward, through provided openings in the valve body wall. The outward extending ends of the pivoting axles are respectively movably connected with the float by means of a lever arm. 
   A disadvantageous aspect in the case of the conventional level limit valves, is that the fuel, suddenly blocked in entry by the shutting flap, fills up the pipe in a very short time and spills out through the inlet fitting. This gives the person attending the gas pump the impression, that the tank is not yet completely full, and as a result, must still be provided with more fuel, or he makes an effort to continue feeding until the gas pump display shows a nice round number. In spite of the use of a level limiting tank valve, measures must be taken, so that in spite of repeated “topping-off efforts” no fuel can enter into an associated, activated carbon filter through the air vent lines. The active carbon loses its effectiveness by contact with liquid fuels. 
   With the protection of the activated carbon filter in mind, the purpose of the invention is to propose a level limit valve, which avoids this disadvantage. 
   SUMMARY OF THE INVENTION 
   This purpose is achieved by means of a level limit valve with the features of the the invention. In accord with these features, a movable coupling is provided between the flap and the float, in which, a lever rod reaches through the discharge port of the valve body, at least in the opened position of the flap. The said lever rod is moreover joined in a linked manner with the flap. The connection is made on the outer side of the flap, which is proximal to the discharge port of the valve. This embodiment makes possible, that the pivoting axle of the flap can be brought entirely within the valve body. Penetrative openings in the valve body, through which the pivoting axle is guided to the outside, are no longer necessary in the invented design. The liquid fuel, which, when the flap is closed, backs up in the filling pipe and shuts off the delivering nozzle, now has no more possibility of continuing to run into the tank. Thus, post-tanking as described, is thus prevented. 
   In an advantageous embodiment, in the valve body is to be found a boring uniting the valve interior chamber with the interior of the tank. This boring is so designed, that it permits only a very small back flow of any fuel which may be trapped in the filling pipe. This will be hardly perceptible to the service person at the pump. After the filling operation of the vehicle, then any fuel remaining in the filling pipe can run back into the tank. 
   In the case of an embodiment, which shows a particular advantage when viewed from a consideration of the technical aspects of manufacture, the valve body is essentially constructed as a cut-off section of tube, whereby on the end surface thereof, confronting the fuel flow, a transverse wall is placed around the outlet port. This transverse wall serves as a carrier of a sealing edge which circumferentially encompasses the outlet port in a ring shaped manner and functions together with the periphery of the flap. Further, this transverse wall serves as a carrier of a bearing seat, which in turn serves for the reception of the pivoting pins which are integral with the said flap. For the mounting of the flap in the valve body, the flap must be introduced therein and its pivoting pins inserted into the bearing seats. The bearing seats are easily made in the process of injection molding by means of valve body webs formed on the inner side of the transverse wall and are made from the circumferential wall of the of the valve body. The pivot pins are formed on the edge of the flap rim by short webs, whereby the body webs, in the assembly stage, extend themselves into the area between the pivot pins and the rim of the flap. 
   In the case of a further advantageous embodiment, on the end surface of the inlet port of the valve housing, a connection fitting is installed, especially with the aid of a snap-in connection. On the end thereof, extending with the flow, are integrally placed two detent projections which extend themselves in axial direction of the valve body. These extend themselves through the inlet port, into the valve chamber and affix the pivot pins in the bearing seats. This arrangement eases the assembly work. Because of the fact, that the connection fitting is not molded onto the valve body, in which it would be of one part with the said fitting, the invented valve body is more easily accessible for the installation of the flap. The affixing of the pivot pins in the bearing seats is carried out simultaneously with the affixing of the said connection fitting onto the valve body. 
   In a further advantageous embodiment of the invention, in the direction of the flow, a flow diverting means is installed. This prevents a direct impingement of the fuel flow against the flap when the latter is in its opened position. By this means, it is excluded, that the inflowing fuel closes the flap, before the specified level in the tank has been reached. The flow diverter narrows the inflowing fuel directly in front of the flap. This narrowing brings about the result, that an entry of the valve flap into the valve body is made more difficult during the assembly. On this account, provision has been made, that the flow diverter is placed in the intake fitting. The flap, in this case, can then, without hindrance, be installed in the valve body. 
   The float is movably set with bearings on a shaped float carrier at the end surface, in downstream of the valve body. The float is essentially installed to pivot in a vertical direction. A connection between the float and the flap is enabled by a through opening, located centrally in the upper side of the float carrier, which opening is penetrated by a lever arm. This connection is particularly sparing of space in a vertical direction and carried out with very few linkages. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The invention will now be more closely described with the aid of the drawings of a presented embodiment example. There is shown in: 
       FIG. 1  a level limit valve in a longitudinal section. 
       FIG. 2  a second level limit valve, slightly changed from  FIG. 1 , in a perspective view 
       FIG. 3  In views A to E, perspective presentations of a float, a flap, and the level arm which binds these two together, and 
       FIG. 4  a cross-sectional view along the line IV—IV in FIG.  2   
   

   DETAILED DESCRIPTION 
   The level limiting valve—hereinafter “valve”—presented in the above illustrations encompasses as its principal components:
         a tube section shaped valve body  1 ,   a float carrier  2  connected with said valve body  1  on an end piece  31  in direction of the fuel flow,   a float  3 , movably set on said float carrier  2 ,   a flap  4 , inside the valve body, which is movably connected by means of a lever arm  5  to the float  3 , and   an intake fitting  6 .
 
The valves are so arranged in the assembly operation, that the center axis  7  of the connection fitting  6 , i.e. also that of the valve body  1 , runs somewhat horizontally.
       

   The valve body  1 , on its top, is somewhat flattened, forming thereby a flat surface  8 . In the case of the embodiment example in accord with  FIG. 1 , on this flat surface  8 , an attachment element  9  is placed. The attachment element  9  possesses a top wall  10  which, when seen in the assembly operation, in a vertical direction from the said flat surface  8 , is somewhat distanced therefrom. A through opening  11  has been made available in said top wall  10 . For the fastening of the valve on the inside of an upper tank wall  13 , this wall  13  exhibits an opening  14 , in which a somewhat pot-shaped carrier  15  is inserted. The carrier  15  lies with a flange  16  on the outside of the tank wall  13 , which flange  16  radially extends beyond the circumference of the carrier  15 . Projecting from the bottom wall of the carrier  15 , is found a pin  17 , the free end of which forms a head shaped locking part  18 , The shape of the through opening  11  in the carrier  15  and the shape of the locking part  18  are so chosen, that the locking part  18  can be inserted into the through opening and after turning, perhaps some 90°, it engages the wall  10  from behind. On the free end of the float carrier  2  a further affixing device  9 ′ is installed, which likewise, works in conjunction with an installed carrier  15 ′ in a tank wall opening  14 ′. In the embodiment example in accord with  FIG. 2 , which is presented without the float  3  or the lever rod  5 , a fastening element  9 ″ is integrally attached which is associated with a wall  10 ″ which has a through opening  11 ″. This works together with a carrier  15  (not shown) installed in the upper tank wall  13 . In case of necessity, additional fastening elements can also be provided on the valve housing  1  or on the float carrier  2 . The carriers  15 ,  15 ′ are welded in place in the final stages of the assembly procedure. 
   The valve body  1  possesses two ports. One, is outflow port  21 , located downstream in flow direction  20  of the incoming fuel in the filling pipe (pipe not shown). The other is the intake port  22  located upstream therefrom. The outflow port  21  is placed in a transverse wall  23 , and has a shape which, in cross-section, follows the outline shape of the valve housing. The upper side  19  of said port (see  FIG. 4 ) runs parallel to the upper, flattened wall section of the valve body, i.e. parallel to the flat surface  8 . Two straight and parallel sections join the said upper side  19 , thus forming side sections  24 . These side sections are bound together by a continuing, bowed bottom side section  25 . The entire rim of the outlet port itself is shaped into a projecting sealing edge  27  which extends upstream into the interior chamber  26  of the valve (FIG.  1 ). The sealing edge  27  acts in conjunction with the outer side of the flap  4  in the sense of a closure of the valve interior chamber  26 . On the wall area  29  of the transverse wall  23  immediately above the outlet port  21 , are placed two bearing seats  30 . These seats  30  are for the acceptance of the integral pivoting pins  33  of the flap  4 . The bearing seats  30  are, respectively, formed from a body web  32  placed on the inside of the valve body wall  34  and the inside of the wall area  29 . The body webs  32  run parallel to the flat surface  8  and possess on their free ends a thickening  35  which serves for increasing their mechanical stability. 
   The flap  4  possesses a shape profile, which follows the cross-sectional shape of the corresponding outlet port  21  and also has in its upper rim, essentially, a straight line section  36  (see FIG.  3 ). On this said rim section  36 , respectively on each side, is formed from an extending or cross piece  37 , a pivot pin  33 . The pivot pins  33  extend in the direction of an imaginary pivoting axis  38 , which, during assembly, runs at right angles to the valve center axis  7  and parallel to the flat surface  8 . Again in the assembly procedure, each pivot pin engages in a bearing seat  30 , whereby, the body web  32  extends itself in each case into the intervening space  39  between the upper edge  36  of the flap  4  and the pivot pins  33  (FIG.  3 E). 
   The float carrier  2 , which retains the float  3 , is essentially shaped as a trough. This carrier possesses an upper wall  40 , upon which are formed lateral side walls  43 , which, in assembly, extend vertically downward. On the outer surface of the wall  40 , which is designed to be flat, are two pair of bearing projections  44 ,  45 . The bearing projections  44  are located proximal to the free end  46  of the float carrier  2  and the bearing projections  45  are placed near to the valve housing  1 . The bearing projections  44 ,  45  are spaced apart in the transverse direction  48  (see  FIG. 2 ) and carry the bearing eyes  47  for the pivoting bearing of the float  3  and the lever rod  5 . 
   The float  3  is bearing supported with a parallelogram-linkage arrangement on the float carrier  2 . This arrangement is constructed with two linkages,  49  and  50 . The link  49  is basically an H shaped injection molding part, having two parallel legs  49   a  and one cross piece  49   b  binding these together. From the ends of the said parallel legs  49   a , more exactly, from their outer surface, extend pivot pins  53 ,  54 . The pivot pins  54  are held by the bearing projections  44 . The two other pivot pins  53  are inserted in the bearing eyes  55  on the underside of the float  3 . On the cross piece  49   b  of the linkage piece  49 , a centrally located detent pin  56  forms an integral projection. This detent pin  56  coacts with a counter abutment  57 , which extends out of the upper wall  40  of the float carrier  2 . This detent arrangement serves for the limiting of the upward movement of said float  3 . The lever rod  5  extends itself between a linkage lever  50  and a linkage lever  69 . The linkage lever  50  is formed from a pivot axle  58  and two lever arms  59 ,  60  integrally placed thereon. The lever  59  comprises two parallel running connectors  63 , the free ends of which are bound together by a pivot pin  64 . The pivot pin  64  lies in a bearing eye, described in more detail below, of the float  3 , while the pivot axle  58 , inserts itself at the free end in the bearing eyes  47  of the bearing projection  45 . The lever arm  60 , on its free end, widens itself into a forked form, whereby the free ends of the fork legs  66  are bound together by a pivot axle  67 . On this pivot axle  67  is a further linkage lever  69 , secured with bearing in eye  68 . The bearing eye  68  possesses a slot  71 , which enables a snap connection with the pivot axle  67 . On its distal end from the bearing eye  68 , the linkage lever  69  possesses two pivot pins  70 , pointing away from one another. The pivot pins  70  in turn, lie in the bearing eyes  73 , which are located in the clips  74 , projecting from the outer side  28  of the flap  3 . 
   In the wall  40  of the float carrier  2  is provided a centrally located opening  75 , extending itself in the direction of the center axis  7  up to the valve housing  1 . On the longitudinal edges of this opening the bearing projections  45  are formed, which carry the linkage lever  50 . The movement path of the lever rod  5 , during the movement of the flap  3 , in its open/shut position, extends itself through this opening  75 . 
   The float  3  is, essentially, a longitudinal section of a cylinder and is also open at the bottom. The float  3  possesses two transverse end walls,  76  and  77 . The transverse wall  76  possesses two bearing projections  78 , which are provided with the bearing eyes  55  to work together with the pivot pins  53 . On the other transverse wall, in the middle is found a holding clip  79  in the free end of which, the bearing eye  65  is found, which receives the pivoting axle  64 . On the outside of the transverse wall  77  are finally, still two, essentially plate shaped projections  80 , the transverse direction  48  intervening distance of which is so dimensioned that the pair of bearing projections  45  finds space therebetween. On the upper side, the float  3  possesses a flattened section  94  stretching in an inclined manner from the transverse wall  76  to the projections  80 . This section  94  limits the height of the float. The valve, on this account, can then be positioned relatively closer to the upper tank wall  13 . 
   The described valve operates in accord with the following. 
   In the illustrated view of  FIG. 1 , the float  3  is not immersed in fuel. The float  3  lies with its transverse walls  76  and  77  and with the flat projections  80  on the upper wall  40  of the float carrier  2 . The flap  4  is now in its open position. So that the inflowing fuel in flow direction  20 , through the inlet fitting  6  and through the valve housing  1 , cannot move the flap  4  into its closed position, a flow diverter  83  is placed ahead (as seen in flow direction) of said flap  4 . This is formed from an inclined piece  81  which is inclined away from the inner wall of the inlet connection fitting  6 . As the end of the tanking process approaches, the fuel level reaches the float  3 , so that this begins to float. 
   The floating movement is carried out in the direction of the arrow  84 , regulated by the parallelogram-linkage arrangement, which was constructed by the linkage piece  49  and the lever arm  59  (See FIG.  1 ). As this occurs the lever arm  60  and the linkage lever  69  swing downward, whereupon, the flap  4  closes. In the closed position, the flap  4  lies with its outside  28  against the sealing edge  27  and prevents a further inflow of fuel into the tank. The fuel then fills up the inlet pipe and brings the feed nozzle to a shutoff point. Thereby, in that the flap  4  is placed completely, including its pivoting axle, inside the valve body  1 , no body penetrating openings are present, through which fuel can flow into the interior of the tank. In order that, even after the end of the tanking procedure, it is made possible that fuel can escape from the filling pipe, underside in the valve body, an escape opening  85  has been bored. The diameter of this boring is so designed, that the fuel flows out very slowly and therefore the sinking of the level of fuel in the filling pipe is scarcely noticeable. 
   To assure a tilt free operation of the pivot pins  33  of the flap  4  in the bearing seats  30 , a bearing web  86  has been made in each, which is formed on the inside of the transverse wall  23  and runs at right angles to the respective housing web  32 . The securement of the pivot pins  33  in the bearing seats  30  is carried out by two detent projections  87 , which extend themselves from that end side proximal to the valve housing  1  of the inlet connection fixture  6  in the direction of the center axis  7  and which terminate shortly before the said bearing seats  30 . 
   The above mentioned pivot pins, that is, pivot axles, and the bearing eyes which accommodate them, exhibit a relatively large amount of play, in order to make possible an easy movability of the combined parts. This easy movability, however, brings along with it, the fact that the float  3 , can move itself in the direction of flow  93 , especially upon impacts, such as the slamming of an auto door during the tanking procedure. This motion can be carried over into a upward float motion in accord with arrow  84 . If this occurs, then the flap  4 , would thereby move in the closure direction, that is, into the fuel feed flow. The fuel, which is then striking against the flap, would then close this flap  4  completely. This would have the result, that the feed nozzle outside would be shutoff, although the tank is not yet full. In order to prevent this, on the end of the float carrier  2  is placed a detent  88 , on which the float  4 , with its cross wall  76  strikes, in case of the said inadvertent sideways movement, i.e. as a result of the slamming of an auto door. The detent  88  is so positioned, that the inadvertent motion of the float  3  is stopped, before the flap  4  leaves the protective back cut area  89  of the flow diverter  83  and immerses itself in the flow of fuel. In the case of a normal float rise, on the other hand, the float rises without hindrance from the detent  88 . 
   An unexpected closure movement of the float  3  can also be called up by an impulse from the kinetic energy of the flow of the fuel. If the upper wall  40  is made without an opening, then an impact of the fuel onto the underside of the float is inevitably certain. If, on the other hand, openings, somewhat like the opening  75 , are available, then the possibility is present, that fuel flows through said opening into the float, and moves this again in the direction of arrow  84  (see  FIG. 1 ) before the tank is filled. In the embodiment shown in  FIG. 1  of a level limit valve, the opening  75 , in this aspect, is scarcely a problem. Otherwise, this effect is more likely by a further opening  90 , which is to be found at the free end of the wall  40 . The linkage piece  49  and the lower area of the bearing clips  78  are pivotable into this opening, whereby the constructive height of the valve can be reduced. In order to hinder an inflow of fuel into this opening  90 , in front of the opening  90 , as seen in the direction of flow, an on the underside of the wall  40 , is place a flow diverter  91 .

Technology Classification (CPC): 8