Abstract:
A closure cap for the filler neck of a reservoir, in particular, one for fuel or motor oil for e.g. motor vehicles, comprising a grip and a rotating lifting device whose first part (sealing part) facing the grip is provided with a sealing ring and whose other part (tightening part), which faces away from the grip and which is provided with detent lugs serving to engage under a closure cap of the filler neck, can be turned relative to the filler neck when the closure cap undergoes a turning motion. The other part (tightening part) can, when the grip undergoes a turning motion, be axially displaced relative to the first part (sealing part) of the rotating lifting device against the force of a spring. This axial displacement is such that, in the closed position of the closure cap on the filler neck of the sealing ring provided on the first part (sealing part), the tightening part is pressed against a sealing surface of the filler neck, and during the movement of the grip, an axial play exists between the sealing surfaces of the sealing ring and filler neck, whereby the first part (sealing part), with the axially acting sealing ring remains, when the closure cap undergoes a turning motion relative to the filler neck, unturnable with the filler neck by means of a turning closing connection.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a closure cap for the filler neck of a container, in particular of a container for fuel or motor oil, for instance for motor vehicles. 
     BACKGROUND OF THE INVENTION 
     In one such closure cap, known from German Patent DE 30 05 419 C2, for a fuel tank, a grip is connected axially and in a manner fixed against relative rotation to one part (sealing part) via a coaxial closing tube, about which closing tube another part (tightening part) is retained axially movably, counter to the action of a spring, in the form of two diametrically opposed locking lugs. A spacer sleeve is disposed between the one part and the other part. The one part carries the sealing ring, which in the locked state of the closure cap rests sealingly on the sealing face of the filler neck. 
     When this known closure cap, introduced into the filler neck, is manipulated, and upon locking or unlocking rotation relative to the filler neck, the closure cap is pressed together with the sealing ring against the sealing face of the filler neck. Since with the rotation of the grip the sealing ring is also rotated relative to the filler neck, the sealing ring rubs to a greater or lesser extent against the sealing face of the filler neck, depending on the force expended by the user. Although because of the rotary lifting device the known closure cap is designed such that before and after the closing position, an axial play is intrinsically possible between the sealing ring and the sealing face of the filler neck, nevertheless, its existence depends on the use by the user. Moreover, a further increase in the friction of the sealing ring relative to the sealing face of the filler neck can occur if the sealing ring swells from the influence of fuel or hot oil, so that the axial play is reduced still further. Moreover, the spacer sleeve that must additionally be provided is complicated. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is therefore to provide a closure cap for the filler neck of a container of the type defined at the outset which prevents friction between the closure cap sealing ring and the sealing face of the filler neck regardless of the use by the user and which is embodied more simply. 
     By means of the provisions of the invention, it is attained that the sealing ring of the closure cap, together with the part that contains the rotation-locking connection, remains stationary upon rotation of the closure cap, or in other words remains nonrotatable relative to the filler neck, so that whether or not the user on rotating the closure cap expends an axial pressure, no friction whatever can occur between the sealing ring and the sealing face of the filler neck. This also means that even if the seal might have swollen, no additional expenditure of force by the user upon rotation is necessary. Moreover, a closure cap of this kind can be used without modification in the currently usual designs of filler necks, which are typically provided with a locking sliding block. 
     An advantageous structural feature with regard to the one part provided with the rotation-locking connection and its mounting to the grip is obtained in that the one part (sealing part), provided with at least one rotation-locking connection element), is solidly connected to a radial flange which is retained axially immovably but rotatably in the grip. 
     Advantageous features with regard to the other part, provided with the locking lugs, and to the connection of the two parts of the rotary lifting device are obtained in that the other part (tightening part), provided with the locking lugs, is embodied as a ring element and is disposed plunging axially partway into a ring element of the one part (sealing part), in that the two ring elements, on their regions plunging into one another, are provided with sliding-block elements, acting in the direction of rotation, in the form of at least one sliding-block path and at least one cam, and in that the one part (sealing part) and the other part (tightening part) are penetrated by a shaft, which is connected in a manner fixed against relative rotation to the grip on one end and to the other part (tightening part) on the other. 
     Particularly for a closure cap made of plastic, advantageous features with regard to the structural embodiment of the relative rotatability of the two parts to one another are obtained in that the spring is disposed in the form of a compression spring between the other part (tightening part) and the shaft, in that the shaft is a cylindrical body, which is provided with a cover plate and whose open end, by means of axial slots engaging via ribs of the grip, forms a rotation-locking connection with the grip on the one hand, and whose closed end, by means of fingers axially protruding from the cover plate and engaging inner axial recesses of the other part (tightening part  18 ), forms a rotation-locking connection with the other part on the other hand; and in that the shaft enters into an axially acting detent connection with the one part (sealing part). 
     Since the locking lugs on the one hand and the rotation-locking connection elements on the other do not cooperate directly with one another, they can advantageously be embodied as of equal width, in accordance with the locking lugs of the other part (tightening part) and the rotation-locking connection elements of the one part (sealing part) each have approximately the same width in the circumferential direction. 
     Because the sealing ring is not subject to any motion friction whatever but instead exerts solely an axial motion on the sealing face of the filler neck, it is possible according to the sealing ring being embodied as a molded part, with toothed sealing face regions optionally oriented toward the filler neck. 
     The invention also relates to an underpressure ventilation device, particularly on a closure cap and in that the shaft on the outer circumference has a sealing ring disk, which is axially retained on the inner edge on the shaft and is placed on the outer edge against an axial sealing face on the one part (sealing part) with intrinsic tension. 
     By these provisions, not only is container ventilation at underpressure obtained, but also an especially low-friction sealing between the shaft and the sealing part of the one part. 
     An advantageous feature of the sealing ring disk is obtained in that the sealing ring disk is embodied as curved convexly toward the axial sealing face, so that a certain two-dimensional sealing action, although narrow, is achieved. 
     By the disposition and optionally adjustable axial bracing of the annular bead in that on the side of the sealing ring disk remote from the axial sealing face, an annular bead is disposed on the other part (tightening part), in a region between the inner and outer edges of the sealing ring disk, and in that the annular bead is disposed at a slight axial spacing from the applicable face region, oriented toward it, of the sealing ring disk, it is attained in a simple way that at a negative pressure in the container, the rubber seal comes free from the sealing face on the annular edge by a hinging motion, and in that case the underpressure that trips the ventilation can be selected as a function of the location of the annular bead. 
     The invention furthermore relates to a filler neck of a container, in particular a container for fuel or motor oil for motor vehicles, for instance, especially for use with a closure cap of a container, in particular of a container for fuel or motor oil, for instance for motor vehicles, in particular for use with a closure cap as having a sealing face surrounding the neck opening and having a closure base, which is disposed inside the neck opening and is axially offset relative to the sealing face, the closure base having preferably two diagonally disposed receiving slots, characterized in that the sealing face is formed by a flat or plane annular sealing face. 
     Such closure caps have a convexly curved annular sealing face in order to achieve a tight closure of the filler neck with the ring seal of the closure cap. This kind of sealing face of the filler neck can essentially be attained only by means of a metal filler neck, or at least a metal outer part of a filler neck, because only then can such a convex sealing face be created in an economical way. Moreover, the filler necks that were previously conventional are provided on their closure base or its lower edge with a sliding-block path, along which the locking lugs slide in the usual closure caps. This too is relatively complicated to manufacture. 
     The object of the present invention is therefore to provide a filler neck of a container of the type defined above that can be manufactured substantially more simply and thus considerably less expensively. 
     In other words, a filler neck of this kind, or the end piece of a filler neck, can essentially be manufactured from arbitrary materials and in particular as a cast or molded part, which is provided with a flat or plane annular sealing face or is provided by postmachining. a flat annular sealing face is several millimeters wide and may then be provided, so that as already mentioned above, a closure cap seal can be embodied as a molded part that acts two-dimensionally. 
     In a further advantageous feature, the underside of the closure base is a flat or plane annular-segmental face, and the filler neck, at least in the region of the neck opening and of the closure base, is a cast or molded part. These, which additionally leads to a further simplification of the filler neck, since the previously necessary sliding-block path can also be dispensed with, so that once again, a cast or molded part that need not be machined or needs only insignificant machining, can readily be used. 
    
    
     
       BRIEF DISCRIPTION OF THE DRAWING 
       Further details of the invention can be learned from the ensuing description, in which the invention is described and explained in further detail in terms of the exemplary embodiments shown in the drawings. Shown are: 
         FIG. 1 , in an exploded perspective view, the individual components of a closure cap for the filler neck of a fuel tank, in accordance with a preferred exemplary embodiment of the present invention; 
         FIG. 2 , a longitudinal section through the closure cap of  FIG. 1 , but in the assembled state and in a state in which a tank filler neck is tightly closed; 
         FIG. 3 , a longitudinal section corresponding to that of  FIG. 2 , but in a position of the closure cap rotated relative to it by 90°, and without the tightening part or the filler neck; 
         FIG. 4 , in an enlarged view, a detail enclosed by the circle IV in  FIG. 2 , but in an intermediate position of the closure cap as it is being screwed onto or off from the tank filler neck. 
         FIG. 5 , a view similar to  FIG. 4  and in further detail reduction and enlarged, the state and  FIG. 2  showing further version of the present invention; 
         FIG. 6 , in an enlarged view, a section through a container neck in a first exemplary embodiment of the present invention, for use with a closure cap of  FIG. 2  or  FIG. 3 ; and 
         FIG. 7 , in an enlarged view of the detail enclosed in the circle VII in  FIG. 2 , in a further feature, the sealing connection of the closure cap and the filler neck. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The closure cap  10  shown in the drawing serves the purpose of gas-tight, liquid-tight, and pressure-tight closure of a filler neck  11  of a container  12 , in particular a fuel tank for motor vehicles, but also of a motor oil container for motor vehicles and for such containers in stationary systems. 
     According to  FIG. 1 , the closure cap  10  essentially comprises a grip  14 , a sealing part  15  with a sealing ring  16 , a ring seal  17 , a tightening part  18 , a compression spring  19 , and a shaft  20 . In the assembled state, as is shown in  FIG. 2 , the shaft penetrates the compression spring  19  and the tightening part  18  and after that is equipped with the ring seal  17 . The shaft  20  furthermore penetrates both the sealing ring  16  and the sealing part  15  that provided with the sealing ring  16 , and the shaft is connected by its applicable end to the sealing part  15  in locking fashion, such that an axially fixed but circumferentially rotatable connection between the shaft  20  and the sealing part  15  is obtained. The applicable end of the shaft  20  is also connected to the grip  14  in a manner fixed against relative rotation and is fixed in the axial direction on the grip  14  in that the sealing part  15  is made in the underside shown in  FIG. 1  of the grip  14  in such a way that it is axially fixed and is rotatable in the circumferential direction. 
     In the exemplary embodiment, the grip  14  is made in one piece of plastic and comprises an approximately cup-shaped underside  22  as well as a grip knob  23  that is designed as longitudinally rectangular, with suitable concave side regions. On the inside, the cup-shaped underside  22  has detent elements  24 , in this case four of them, distributed or integrally formed uniformly over the inner circumference, for axially fixed yet rotatable, locking reception of the sealing part  15 . The grip  14  on the inside, in the region of the hollow grip knob  23 , has diagonally opposed ribs  25 , in this case four of them, which serve the purpose of connection to the shaft  20  in a manner fixed against relative rotation. A bore  26  centrally in the grip knob  23  serves to receive a chain or strip for retaining the closure cap  10  in captive fashion on the applicable filler neck or container. 
     The sealing part  15 , which is in one piece of plastic, has an annular disk  28 , which is provided with an undercut circumferential edge  29  that serves the purpose of locking in the grip  14  or behind the detent elements  24  of the grip  14 , in such a way that the annular disk  28  is axially firmly held on the grip  14 ; via axial struts, it presses against a bottom  27  of the cup-shaped underside  22  and is held freely rotatably in the circumferential direction. The annular disk  28  is provided with a cylindrical motion-transmitting extension  30 , whose inside diameter is larger than that of the central bore in the annular disk  28 , so that an inner shoulder  38  is created. The motion-transmitting extension  30  is provided with rotation-locking lugs  31  on two diametrically opposed outer circumferential regions, which protrude radially and have a certain width in the circumferential direction and originate in the axial direction at the free end of the motion-transmitting extension  30  and which leave an axial space free between them and the surface of the annular disk  28 . It is in this free space that the sealing ring  16 , placed on the annular disk  28 , is held between the annular disk and the sealing rotation-locking lugs  31 . The motion-transmitting extension  30  is provided on its inside with two identical, diametrically opposed sliding-block paths  32 ,  33 , which act in the axial direction ( FIG. 3 ). The sliding-block paths  32 ,  33  are made in the wall of the motion-transmitting extension  30  in the axial direction from its free end inward, in such a way that they occupy approximately half the thickness of the wall of the motion-transmitting extension  30 . Each of the sliding-block paths  32 ,  33  begins in the region of one side of one rotation-locking lug  31  and extends along its width across a circumferential angle of 90° . On both ends, the sliding-block path  32 ,  33  has a respective end stop  34  and  34 ′. The sliding-block path  32 ,  33  has a symmetrical course at 45° with regard to its center; that is, a first path portion  35  begins at the 0° stop  34  at a certain axial width and then changes over, rising, to a second path portion  36 , which viewed axially has a lesser depth and extends uniformly to both sides of the 45° center; after that, a third path portion  37  adjoins it, extending symmetrically to the first path portion and hence downward and ends at the other 90° stop  34 ′. The two sliding-block paths path portion  32  and  33  are offset circumferentially from one another by 180°. 
     The tightening part  18 , which is likewise in one piece of plastic, has an outer, smaller-diameter, first annular portion  39  and a second annular portion  40  of larger outer diameter, the first of which in the assembled state plunges into the motion-transmitting extension  30  of the sealing part  15 , where it is held movably in the axial and circumferential directions. With its shoulder  41  between the two annular portions  39  and  40 , the tightening part  18  rests on the free face end of the motion-transmitting extension  30  in the assembled state. In this state, for instance as in  FIG. 2 , two cams  42  and  43 , which are integrally formed onto the outer circumference, diametrically radially from the first annular portion  39  and axially from the shoulder  41 , plunge into the respective sliding-block path  32  and  33  in the sealing part  15 . 
     As will be described hereinafter, the tightening part  18  is moved back and forth in the axial direction upon a relative motion 90° relative to the sealing part  15 , because of its cams  42 ,  43  and the sliding-block paths  32 ,  33 . The sealing part  15  and the tightening part  18  thus form a rotary lifting device  13 . 
     In the circumferential region of the cams  42 ,  43 , the second annular portion  40  has diametrically opposed locking lugs  44 , protruding radially from its circumferential side, which in the assembled outset state are aligned in the axial direction with the rotation-locking lugs  31  of the sealing part  15 . In the exemplary embodiment, the circumferential width of the locking lugs  44  is therefore equal to the circumferential width of the rotation-locking lugs  31 . 
     On the inside circumference, the second annular portion  40  is provided both with an annular recess  45  and with two diametrically opposed axial grooves  46 . Both recesses  45  and  46  extend, viewed radially, over a portion of the wall thickness of the second annular portion  40 . The annular recess  45  begins at the free annular face end of the second annular portion  40 , and the grooves  46  adjoin it. The axial grooves  46  rest on the circumference in the region of the locking lugs  44 . 
     The plastic shaft  20  is hollow and on its end has a cover plate  51 , whose diameter is greater than the outer diameter of a cylindrical portion  52  of the shaft  20 ; the two parts are disposed concentrically to one another. The diameter of the cover plate  51  is such that the cover plate can plunge, axially movably, into the annular recess  45  of the second annular portion  40  of the tightening part  18 . Diametrically opposed regions of the cover plate  51  are provided with fingers  53 , protruding axially from its underside, which are capable of plunging into the axial grooves  46  in the second annular portion  40  of the tightening part  18 , as a result of which the tightening part  18  is retained on the shaft  20  on the one hand in a manner fixed against relative rotation but on the other hand axially movably. The compression spring  19 , which surrounds the cylindrical portion  52  of the shaft  20 , is retained between the cover plate  51  and an inner shoulder  47  of the first annular portion  39  of the tightening part  18 . 
     The cylindrical portion  52  of the shaft  20 , on its free end, on the one hand has a detent annular groove  54 , which receives the inner edge of the annular disk  28  of the sealing part  15  axially fixedly but circumferentially rotatably. This end furthermore here has four axial slots  145 , diametrically opposite one another in pairs, which are engaged for the connection fixed against relative rotation by the ribs  25  of the grip  14 . On the cylindrical portion  52  of the shaft  20 , axially spaced apart from the detent annular groove  54 , a receiving annular groove  56  is also provided, and the ring seal or rubber seal  17  is received in it, and in a manner to be described hereinafter provides for container ventilation at underpressure. 
       FIG. 6  in conjunction with  FIG. 2  shows a filler neck  11 , or an extension end of a filler neck, which has typical external dimensions. The filler neck  11  has a tubular part  61 , which either merges with the container in question or is secured to a filler tube extension from the container  12 . The tubular part  61  tapers on its free end to form a closure base  62 , which has an annular sealing face  63  which surrounds the neck opening  60  and is in turn adjoined radially inward and axially offset by a locking edge  64 . This locking edge  64  is provided, in two diametrically opposed regions, with a radial recess  65 ,  66 , into which when the closure cap  10  is put in place the aligned rotation-locking lugs  31  and locking lugs  44  plunge. In the exemplary embodiment shown, the annular sealing face  63 , against which the sealing ring  16  on the sealing part  15  presses, is embodied as a flat plane face. Besides having a plane top side  68 , the locking edge  64  in particular also has a plane or flat underside  69 . The axial thickness of the locking edge  64  is approximately equal to the axial height of the rotation-locking lugs  31  of the sealing part  15 . The underside  69  has a chamfer  70  at the transition to the inner circumference of the locking edge  64 . 
     If the assembled closure cap  10 , in the outset position, in which the rotation-locking lugs  31  of the sealing part  15  and the locking lugs  44  of the tightening part  18  are located axially one above the other or in other words are aligned, is placed on this filler neck  11 , then the rotation-locking lugs  31  get into the radial recesses  65  of the locking edge  64  of the closure base  62  and are received there with circumferential play and the locking lugs  44  to under the locking edge  64 . With the rotation of the closure cap  10  at the grip knob  23  of the grip  14 , the sealing part  15  is firmly retained so that the sealing ring  16  itself remains nonrotatable as well. Since the tightening part  18  is connected to the grip  14  in a manner fixed against relative rotation and is free from the locking edge  64 , the tightening part  18  rotates relative to the sealing part  15 , and as a result, the rotary lifting device  13  comes into action. In other words, the cams  42  and  43  of the tightening part  18  move along the sliding-block paths  32  and  33  of the fixed sealing part  15 , so that the tightening part  18 , counter to the action of the compression spring  19 , moves axially in the direction of the cover plate  51  of the shaft  20  and along the shaft  20 . As a result, the locking lugs  44 , with an axial spacing from the underside  69  of the locking edge  64 , move in the circumferential direction along this underside  69 . At the end of this 90° rotary motion of the tightening part  18 , the cams  42  and  43 , from the second path portion  36  that has caused the axial motion, get into the lower-lying third path portion  37  under the influence of the compression spring  19 , which means that the locking lugs  44  are actively pressed against the underside  69  of the locking edge  64 , and as a result the sealing ring  16  is sealingly pressed in the axial direction on the annular sealing face  63  of the closure base  62  of the filler neck  11 . In this closing position shown in  FIG. 2 , the locking lugs  44  are offset by 90° from the rotation-locking lugs  31 . 
     The release of the closure cap  10  from the filler neck  11  is done correspondingly in reverse and once again the tightening part  18  with its locking lugs  48  is lifted in the axial direction from the closure base  62  and, after a contrary 90° rotation, is set down on the sealing part  15 . This means that the sealing ring  16  relative to the annular sealing face  63  of the filler neck  11  always completes only an axial motion but not a rotary motion relative to it. Depending on the design of the first and third path portions  35 ,  37 , the setting-down motion of the tightening part can make the locking action audible. 
     An essential aspect in this connection is that the filler neck  11  can in this way be made from a molded or cast part, and the plane faces  63  and  69  can be created either by the production of the cast part or by postmachining. Since the sealing ring  16  is pressed by the active axial motion against the plane annular sealing face  63 , it is not necessary—as in filler necks that were conventional until now—to provide a narrower sealing face that is provided by means of arching. 
     In the exemplary embodiment of  FIG. 7 , the sealing ring  16  can therefore be embodied as a molded part; in this case, the purely sealing face region can be interrupted by annular grooves  71 , so that annular sealing face regions  72  remain, which can enter into gas-tight, liquid-tight, and pressure-tight connection with the annular sealing face  63  of the filler neck  11 . This is accomplished over a relatively wide annular sealing face of several millimeters in width, for instance, on the filler neck  11 . 
     In  FIG. 5 , in accordance with a further exemplary embodiment, the action of the ring seal  17 , which is embodied as a rubber seal, can be seen. This rubber seal  17 , which is retained on the cylindrical portion  52  of the shaft  20  in the receiving annular groove  56  thereof, is embodied such that it is curved in convex fashion in the radial direction toward the inner shoulder  38  of the sealing part  15 , which here forms an axial sealing face, and there presses with its outer edge region  58  with intrinsic tension (solid lines). Axially diametrically opposite, on the tightening part  18  or on the face end of its first annular portion  39 , an axially protruding annular bead  48  is provided, which in the assembled state is at a slight axial spacing from the rubber seal  17 . Whenever an underpressure is built up in the container  12  communicating with the filler neck  11 , this annular bead  48  serves to ventilate the container  12 . If an underpressure occurs, the outer peripheral region of the ring seal  17  is aspirated and is pressed against the annular bead  48 , and is possibly bent somewhat past this annular bead  48 , as a result of which the sealing face  58  of the ring seal  17  lifts (dot-dashed lines) from the sealing face of the inner shoulder  38  of the sealing part  15  and as a result creates an air communication between the outer region and the inner region of the container  12 . Depending on the radial position and axial closeness of the annular bead  48  to the rubber seal  17 , the level of the underpressure in the container  12  at which a deflection of the rubber seal  17  and thus a ventilation of the container  12  occur can be selected. 
     It is understood that the above-described closure cap  10  can be used not only in the filler neck  11  described in conjunction with  FIG. 6  but also in currently usual filler necks, which in particular are provided with a sliding-block path on the inside of the locking edge  64  for commercially available closure caps.