Abstract:
A roller blind ( 15 ) comprising a spring actuated roller blind for the luggage area ( 2 ) of a vehicle which includes a positive or compulsory guiding device ( 27 ) to which the front edge of the roller blind ( 17 ) is detachably connectable. The positive guiding device ( 27 ) ensures that the roller blind ( 17 ) can be moved upwardly to an intermediate position when the tailgate ( 8 ) is opened in order to provide easy access to the luggage area without having to fully roll the roller blind ( 17 ) back into the roller blind housing ( 16 ).

Description:
FIELD OF THE INVENTION 
     The present invention relates to devices used in automobiles, and more particularly to an improved roll cover for covering the cargo space of an automobile. 
     BACKGROUND OF THE INVENTION 
     Roll covers are increasingly used in station wagons in the cargo space because the cargo space would be fully visible from the outside without appropriate measures. The roll cover is capable of protecting the upward facing cargo space from outside viewing. The roll cover is bordered on one side by the rear bench back rest, the two car body walls and the tailgate. On the other hand, the cover allows the full utilization of the cargo space when it is rolled up in its rest or storage position where it hardly needs any space. 
     To cover a cargo space, two different systems are known. One system is designed as a type of folded cover consisting of a cover sheet with rods or hoops. The hoops run on guide rails at the car body side and must be somewhat parallel. When opened, intermediary positions are possible, but their installation is costly because of the guide rails. 
     The roll cover can be placed at any time in various intermediate positions. 
     The other system, as shown in U.S. Pat. No. 5,224,748, for example, is designed as a type of spring-actuated shade. It consists of two connected end caps with a rotating winding roller in the middle. The roller blind is attached to the winding roller, while the other end is connected to a pull bar. The winding roller is prestressed with a spring in the direction where the roller blind is rolled up. 
     On the side of the roller blind path, two guide rails with two hooks each are attached. One hook is located at the tailgate opening while the other is arranged half-way from the winding roller and the hook above to allow a half-opened position of the roll cover. To reach this position, the user must manually unhook the pull bar from the rear hook and transfer it to the front hook; he has to control this movement himself. 
     Another solution is offered by DE 39 41 711 C2. The cargo space cover is again designed as a type of spring-actuated feed shade. It consists of an oblong cassette housing with a rotating winding roller. The roller blind is attached to the winding roller and its free end is connected to the pull bar. The pull bar is hooked into the inside of the tailgate at such a height that the roller blind pull bar, which extends horizontally across the cargo space will change when the tailgate is closed. 
     The attachment of the pull bar on the inside of the tailgate is supposed to increase comfort. 
     The connection with the tailgate lifts the roller blind automatically when the tailgate is opened upward. Therefore, the access opening is automatically opened with the open tailgate without requiring additional movements such as unhooking the pull bar. 
     A significant disadvantage of the known solution is that the pull bar is necessarily pulled out of the tailgate opening when it is opened, or is to be closed by the tailgate, and moved a bit upward. Due to the roof configuration in modern car body forms, the tailgate is increasingly narrowed toward the roof, causing the sides of the roller blind in the well-known design to rub at the edges of the tailgate opening. In this area, the cover suffers unsightly damage. The known solution has another disadvantage in that the maximum extent of the roller blind to be rolled onto the winding roller does not result from the size of the cargo space opening but rather from the location of the final position of the pull bar when the tailgate is open. This amount of roller blind is significantly larger than what is needed for covering only the cargo space opening. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     In view of the foregoing, an object of the invention is to create a roll cover that is designed like a spring-actuated shade and easy to handle without being damaged when the tailgate is opened. 
     The present invention provides these and other advantages and overcomes the drawbacks of the prior art by providing a roll cover having a compulsory guiding device which allows the cover to be moved upward when the tailgate of the automobile is opened so as to allow easier access into the cargo space. 
     The use of a compulsory or positive guiding device with an appropriate design prevents the pull bar from being pulled out of the tailgate opening when the tailgate is opened, while creating at the same time a relatively large access to the cargo space. The user is not required to unhook the roll cover after opening the tailgate and to let it wind completely onto the winding roller to get access to the cargo space. Rather, this form of a compulsory guiding device allows the pull bar to hold in an intermediate position which results in similar comfort as with roll covers that work with a gather principle and rods on rails. 
     The roller blind is generally as large as the length of the cargo space opening, measured in the direction parallel to the longitudinal direction of the vehicle. 
     Even if the compulsory guiding device must be actuated manually, there is a substantial simplification in that the operator does not have to bend forward to reach the intermediate position in order to guide the pull bar up to the roll cover housing. The compulsory guiding device lifts the pull bar and prevents an unpleasant forward bent body position. 
     The intermediate position can be realized in several ways. When in the intermediate position, the pull bar lies in a height clearly above the closed position, while in other cases the pull bar in the intermediate position is only retracted in the direction of the housing. 
     The circumstances are technically very simple when the compulsory guiding device holds the pull bar also in the closed roll cover position so that re-hanging is not needed. 
     The force for transferring the pull bar from the closed position to the intermediate position or the reverse can be accomplished by means of coupling links that couple the movement of the pull bar at least over a part of their motion field with the movements of the tailgate. These coupling links can be designed as pressure resistant and/or flexible. If only the movement direction is considered, it suffices that the coupling links transfer only the tensile force. In the event that the movement exerted on the tailgate end is higher than the lift on the pull bar with the compulsory guiding device, the coupling links can also be flexible. 
     The compulsory guiding device can be designed in different ways. A relatively simple compulsory guiding device consists of two one-armed levers that are arranged in the cargo or trunk space in a pivoting manner. They face from their hinge point in the direction of the cargo opening and have receptacles for the ends of the pull bar at their other ends. By pivoting the levers upward either manually or controlled by the tailgate motion, the access opening is reached in the desired size. 
     Another compulsory guiding device uses guide rails attached to the lateral rims of the cargo space opening. Slides are running on these guide rails. Each of these slides has a receptacle for the pull bar so that the pull bar, i.e., the extended end of the roller blind, can be placed at the appropriate height so that access to the cargo space is unimpeded. 
     When using the guide rails and slides, the slides are kinematically connected with the tailgate. The connection with the tailgate has, besides the greater comfort for the operation from outside, the technical advantage that it forces a synchronous movement of the pull bar ends and prevents jamming. 
     Depending on the way the connecting or coupling links between the tailgate and the compulsory guiding device are designed, springs must be used to enforce an end position of the compulsory guiding device, or such springs are not needed. 
     No springs are needed when the coupling links between the tailgate and the compulsory guiding device are rigid and inflexible. In contrast, springs are needed when the coupling links are not tensile pressure resistant. The latter can be advantageous example, when no good directional point for the coupling links can be found at the tailgate so that their movement stroke corresponds with the movement stroke of the compulsory guiding device. If the stroke is too small, the compulsory guiding device could, for example, be prestressed with springs in the opened position and be withdrawn to the closed position against the effect of these springs when the tailgate is closed. 
     The reverse solution is also applicable. The springs can run either in the guide rails or prestress the levers as coil springs. 
     Another embodiment instead of the use of coupling links to bring the pull bar automatically in the intermediate position consists of the utilization of the retracting force with which the roller blind is wound onto the winding roller. In order to assure a certain synchronization with the motion or the position of the tailgate, respectively, a locking device has to be installed that functions together with the compulsory guiding device. This locking device has three different states. In the first state, a movement of the pull bar is arrested from a closed position. This allows the user to bring the pull bar permanently in a position corresponding with the closed position of the roll cover. The locking device has a second state when the pull bar can move unimpeded from the closed position to the intermediate position by means of the compulsory guiding device. The third state of the locking device holds the pull bar in the closed position depending on the position of the tailgate. The pull bar is automatically placed in this position when the tailgate is closed. 
     The kinematic circumstances are very simple when these three states of the locking device are realized by at least two different positions of the pull bar. In this, the second and the third state correspond loosely with the different closing positions of the roll cover; the positions of the pull bar differ from one another only by a few millimeters. 
     The situation is especially simple when the pull bar works together with the locking device because the hooking in and out is very simple. 
     A very simple locking device results when a groove is provided into which the pull bar is placed. The groove has a pocket-like recess or a slot so that the tensile force of the winding roller causes an automatic insertion of the pull bar end into the pocket; this position of the pull bar in the pocket corresponds with the first state of the locking device. 
     In order to transfer the pull bar out of the pocket in the third position, the pocket can either have a movable wall or a corresponding lifting link. This lifting link can be a cam that moves the pull bar from a position corresponding to the third position of the locking device when the tailgate is closed. 
     So that the pull bar remains in the third position as long as the tailgate is opened, a holder can be used that locks the groove during that time. 
     This holder can be a ram seated at the tailgate or a slide activated by a cable or a ram that extends into the motion path of the tailgate. 
    
    
     These and other features and advantages of the invention will be more readily apparent upon reading the following description of preferred exemplary embodiments of the invention and upon reference to the drawings wherein: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing a roll cover of the invention in the extended upward position in the trunk of a car with an open car body. 
     FIG. 2 shows another embodiment of the roll cover with slides and rigid couplings in a representation similar to FIG.  1 . 
     FIG. 3 is a top view showing the right tailgate rim of the embodiment in FIG.  2 . 
     FIG. 4 shows an embodiment of the roll cover similar to the one in FIG. 1 but with flexible coupling links. 
     FIG. 5 is a perspective view showing another embodiment of the roll cover of the invention in the cargo space of an automobile in an intermediate position with an open car body. 
     FIG. 6 is a section view taken in plane in vertical relation to the pull bar showing the locking device located at the side and at the end of the guiding groove for the roll cover according to FIG. 5 in its first state. 
     FIG. 7 is a sectional view showing the locking device according to FIG.  6 . 
     FIG. 8 is a view similar to FIG. 6 showing the locking device in FIG. 6 in another state or condition. 
     FIG. 9 is a view similar to FIG. 6 showing the locking device in FIG. 6 in still another state. 
     FIG. 10 is a lateral view showing another embodiment of the locking device for the arrangement in FIG.  5 . 
     FIG. 11 is a perspective view showing the arrangement in FIG.  10 . 
     FIG. 12 is a lateral view showing a third embodiment of a locking device for the roll cover in FIG. 5 partially opened in the first state. 
     FIG. 13 is an enlarged perspective view showing the holder for the locking device in FIG. 12 as well as the actuating cam. 
     FIG. 14 shows the locking device in FIG. 12 in the third state. 
     FIG. 15 is a perspective view of the car tailgate showing an exemplary embodiment of the roll cover with the horizontal pull bar. 
     FIG. 16 shows a locking device for the roll cover in FIG. 15 in lateral view and in the first state. 
     FIG. 17 shows the locking device in FIG. 16 in the third state, and 
     FIG. 18 shows the locking device in FIG. 16 in the second state. 
    
    
     While the invention will be described and disclosed in connection with certain preferred embodiments and procedures, it is not intended to limit the invention to those embodiments. Rather it is intended to cover all such alternative embodiments and modifications as fall within the spirit and scope of the invention. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows a tailgate  1  of a station wagon or car in perspective. Its cargo space  2  is bordered by a bottom  3  as well as two side walls  4  of which only the right side wall can be seen. A rear side window  5  is above side wall, and the seat back  6  of a rear bench forms the front boundary of the cargo space  2 . The side window  5  ends with its lower rim at a distance above the bottom  3 . 
     Access to the cargo space  2  is provided by the tailgate opening  7  which can be optionally locked by a tailgate door  8 . The tailgate door  8  is connected with the auto body by means of hinges  9  and can be kept in an open position with a gas pressure spring  11 . The tailgate opening is limited at the sides by two lateral rims  12  that run parallel to each other as far as the car body contour permits. The tailgate opening  7  is bordered by an upper rim  13  at the roof and a cargo board rim  14  located more or less at the bottom  3 . 
     With the closed tailgate door  8 , there is a cargo space open to above that is limited at the rim by the inside of the tailgate door  8 , the two side walls  4  and the rear side of the seat back  6 . This cargo space opening allows visibility from the outside into the cargo space  2 . 
     To protect the cargo space  2  from outside viewing, a roll cover  15  is used. It comprises a housing  16  as well as a roller blind  17  to cover the cargo space opening. 
     The housing  16  is an oblong housing attached on the back rest of the seat back  6  and extending over its whole length. The interior of the housing  16  contains a winding roller  18  that can rotate at the end. The length of the winding roller corresponds approximately with the length of the housing  16 . 
     The winding roller  18  is at least in one segment tube-like and contains a spring motor  19  that is connected at one end  21  with the winding roller  18  while its other end  22  is fixed in the housing  16 . 
     The rim of the roller blind  17  is attached to the winding roller  18  and its other rim exits the housing  16  through a lengthwise slot  23 . The slot  23  extends almost over the whole length of the housing  16  and parallel to the winding roller  18 . 
     A loop  24  on the roller blind is located at a rim facing away from the winding roller  18 . It contains an essentially rigid pull bar  25  whose ends protrude at the pegs  26 . 
     To guide the pull bar  25  and thus also the front rim of the roller blind  17 , a compulsory guiding device  27  is provided. This compulsory guiding device  27  comprises two one-armed levers  28  of which only one is visible due to the partial illustration of the tailgate  1 . 
     The lever  28  can be pivoted around a horizontal axis with a hinge  29  at one of its ends on the side wall  4 . The pivot axis extends parallel to this axis of the winding roller  18 . The other end of the lever  28  has a fork-shaped receptacle  31  into which the peg  26  can be latched. 
     The not shown other lever is located in opposing relation at the other side wall coaxial to the visible lever  28 . The exact location of the hinge  29  is explained in the following function description. 
     The handling and working of the described roll cover  15  and of the compulsory guiding device  27  is as follows: 
     With the open cargo space  2 , the roll blind  17  is in a rest position rolled up completely on the winding roller  18  due to the function of the spring motor so far that the loop  24  on the pull bar  25  abuts the slot  23  on the outside of the housing  16 . The two loosely pivoting levers  28  are in the position  28 ′ shown in dashes in FIG. 1 where they are held by stops  32  attached below on the respective side wall  4  next to the tailgate opening  7  and support the lever  28  below its receptacle fork  31 . 
     When no visibility is wanted into the cargo space, the roll cover  17  is drawn out of the housing  16  against the effect of the spring motor  19  by means of the pull bar  25  and possibly with the aid of a loop configured pull chain  33  attached to it. The roller blind  17  is pulled out so far until the two pegs  26  can be hooked into the two receptacle forks  31  on the two levers  28 . The receptacle forks are open to the top in this position. In addition, the arrangement is made in the way that the now stretched roller blind, shown with dashes in FIG. 1 in this position and marked with  17 ′, runs below the pivot axis of the bearing. This results in a minor torque in each lever  28  in the position  28 ′ that presses the lever  28  downward onto the stops  32 . 
     The stretched-out roller blind  17 ′ runs horizontal and slightly below the lower rim of the side window  5  under the upper rim of the seat back  6 . 
     When the tailgate door  8  is closed, the cargo space  2  can no longer be looked into. 
     If needed, additional stops at the tailgate door  8  press the pull bar  25  down and thus the levers  28  against the stops  32  so that they will not rattle or snap upward during driving vibrations. 
     When the cargo space is being loaded or unloaded, the access opening between the pull bar  25  is pivoted downward and the upper rim of the cargo board rim  14  remaining after opening the tailgate door  8  will be too small to permit comfortable handling. Therefore, the pull bar  25  is grasped manually and lifted and moved under the effect of the compulsory guiding device  27  in a circular arch with the axis of the hinges  29 . The pivot motion is limited by other stops located, for example, in the hinges  29 . The final position corresponds with the position shown in FIG. 1 with solid lines. 
     The two levers  28  are kept in a lifted position by the spring motor  19 , as is illustrated, and the access opening to the cargo space  2  is now clearly enlarged and the roller blind is no longer in the way. Because of the compulsory guiding device, it is not necessary to let the roller blind  17  roll back into the housing  16 . 
     After loading and unloading the cargo space  2 , the roll cover  15  can be returned to the covering position along the dashes simply by moving the pull bar  25  or the front rim of the roller blind  17 , respectively, downward until the levers  28  rest on the stops  32  as described above. 
     It is also possible at any time, like with any window shade, to remove the roller blind  17  completely by unhooking the pull bar  25  with its two pegs  26  out of the receptacles  31  and guiding it manually in the direction of the slot  23 . With this motion, the spring motor  19  rolls the roller blind  17  again on the winding roller. 
     FIG. 2 shows a different embodiment of the roll cover  15 . The necessary components have already been described in conjunction with FIG.  1  and they are either identical or have the same function and are used with the same reference number without a repeated explanation. 
     FIG. 2A is a fragmentary perspective illustrating the spring motor drive for the roller blind shown in FIG. 2, similar to the spring drive depicted in the FIG. 1 embodiment. 
     The significant difference to the embodiment illustrated in FIG. 2 is that the compulsory guiding device  27 , as shown in FIGS. 2 and 3, comprises two guiding rails  35  attached inside the car body next to the side rims  12  of the tailgate opening  7 . The figures illustrate again only one of the two guide rails because the other cannot be seen due to the cut-off presentation. 
     The guide rails  35  each have a C-shaped profile and form for the schematically shown slides  36 . Each slide  36  carries at its lower end the fork-shaped receptacle  31  in which the two pegs  26  of the pull bar  25  are hooked. 
     Additionally, each slide  36  is kinematically connected to the tailgate door  8  via a connecting rod  37 . The connecting rod  37  is connected at  38  so that it can rotate with the slide  36  and hinged at  39  at the tailgate door  8  adjacent to its hinge. 
     The rod  37  is rigid and forces a motion of both slides  36  along their respective rails  35  during the opening and closing motion of the tailgate door  8 . 
     In principle, the handling of the roll cover in FIGS. 2 and 3 is the same as the handling in the embodiment shown in FIG.  1 . 
     When the cargo space  2  must be closed, the pull bar  25  with its pegs  26  is hooked into the two slides  36 . These two slides  36  are in their upper position when the tailgate  8  is open and hold the hooked-in pull bar  25  in an upper position which is higher than that pull bar position when the cargo space  2  is closed. 
     The position shown with lines in FIG. 2 in which the tailgate door  8  is pivoted down, the two rods  37  by necessity also press the slides  36  in the guide rails downward. When the tailgate door  8  is completely closed, the roller blind  17  runs almost horizontal, as shown with dashes in FIG.  2 . 
     When the tailgate door  8  is opened, the slides  36  are again pulled upward and also lift the roller blind  17  up. 
     FIG. 4 shows that it&#39;s possible to use rope-like coupling links  37  instead of the rigid coupling links. The rope-like coupling links are attached to an ear  41  located on the inside of the tailgate door  8 . 
     Since a coupling link  37  of this type can only move the respective slide  36 , a pre-stressed spring  42  is provided for the opposite movement and runs along the respective guide rail and prestresses the slide  36  against the effects of the coupling link  37 . In the illustrated embodiment, the spring runs as a tension spring from slide  36  to the lower end of the guide rail  35 , i.e., the slides  36  are constantly prestressed by the springs  42  in a position corresponding to the closed roll cover. When the tailgate door  8  is closed, the slides  36  run downward because of the effect of the springs, while they are pulled up against the effects of the springs when the tailgate door  8  is opened. Otherwise the handling and function is identical to that described with the previous exemplary embodiments. 
     Although not illustrated in detail, the coupling links  37  can also have levers with a compulsory guiding device  27  and, conversely, embodiments are possible where the compulsory guiding device  27  has rails but no coupling links  37 . However, the use of coupling links has the significant technical advantage that, controlled by the tailgate door  8 , both ends of the pull bar  25  are moved in a synchronous manner and no jamming can occur. 
     FIG. 5 shows a different embodiment. The necessary components have already been described in conjunction with FIG.  1  and they are either identical or have the same function and are used with the same reference number without a repeated explanation. 
     The exemplary embodiment in FIG. 5 has as the compulsory guiding device  27  two grooves  43 , only one of which is shown because of the partial perspective. The groove  43  is rectangular in its cross-section and begins at the front of the vehicle in the side rim  12  of the tailgate opening  7  facing in the direction toward the roof rim. The groove  43  ends a significant space in front of it. Its width corresponds with the diameter of peg  26 . Its end closest to the roof is closed. 
     At the side rim  1 . 2  on the other side of the tailgate opening  7  (not shown) is the mirror-image groove  43 . Both grooves are opened to each other and follow the rear contour beginning at the front in the direction of the roof. Because of this design, the distance of the lower end of  43  from the cover housing  16  is larger than the distance of the upper end, i.e., when the peg  26 , starting with the front, is moved through the groove  43  in the direction of its roof side end, the roller blind  17  is driven forward a short distance. 
     Because of this arrangement, the roll cover  15  will constantly assume the position shown in FIG.  5 . In order to cover the cargo space before closing the tailgate door  8 , the lower end of the groove  43  has a locking device  44 . The locking device  44  is visible in FIG.  5  and has its mirror image on the left vehicle side. The explanation of the arrangement and effect of the locking device  44  can be limited to one of the two locking devices. 
     FIGS. 6 to  8  show the locking device  44  schematically. As can be seen in the figures, the groove  43  runs in the area of the locking device  44  through a housing  45  shown cut off. The groove  43  forms on its lower end in its forward side wall a pocket or a recess  46  in the direction of the winding roller  18  and runs additionally into another receptacle groove  47  which on the level of the recess  46  leads at first horizontally in the direction toward the invisible tailgate opening  7 . After a short stretch, the receptacle groove  47  forms a descending 180° arch  48  after which the receptacle groove  47  widens at  48  in a funnel shape and forms a joining funnel. 
     On the side facing away from the tailgate opening, the housing  45  contains a partially cylindrical recess  51  that cuts the front side wall of the groove  43  (left in the figure) as can be seen in FIG. 7; i.e., on both sides of the recess  51 , the groove wall segments  52  and  53  remain and continue into the recess  46 . The partially cylindrical recess  51  contains a lifting element  54  in the form of a sector-like disk that is contained in the recess  51  and can be pivoted to a limited extent. The lifting element  54  is limited by a cylindrical outer surface with the same diameter as the partially cylindrical recess  51  as well as by two straight surfaces  56  and  57  running like tendons. The surfaces  56  and  57  face the groove  43 . The lifting element  54  can be pivoted around an axis that runs parallel to the adjacent side wall of the groove  43  and extends horizontally. 
     The pivot limitation of the lifting element  54  is attained by means of a rib  58  protruding in the recess which works together with the arch-like recess  59  in the cylindrical surface  55 . 
     In addition, the housing  45  contains a sliding ram  61 ; its inner end  62  faces the groove  43  and its outer end  63  protrudes into the motion path of the tailgate door  8  on the level of the front. The ram  61  forms, at the same time, a holder and is attached as a slider by means of the boring  64  whose axis faces the cylindrical recess  51  above the pivot axis of the lifting element  54 . 
     The roll cover  15  in FIG. 5 functions as follows: 
     The start position of the roll cover  15  is shown in FIG.  5 . In this position the pegs  26  of the pull bar  25  abut to the end of the groove  43  that is closest to the roof. The pegs  26  are held in this position by the reverse force of the spring motor  19  of the winding roller. 
     To cover the cargo space opening before closing the tailgate door  8 , the user exerts downward pressure on the rim of the roller blind  17  that is stiffened by the pull bar  25 . The pegs  26  slide though the side grooves  43  of the compulsory guiding device  27  until they reach its lower end. Again, due to the spring motor  19 , the two pegs  26  are pulled in the recess  46 , and at the same time the disk-like lifting element  54  is turned in the direction shown in FIG. 6 which jumps back into its surface  56  against the clearance of the recess  46 . On each side of the tailgate opening  7 , the respective peg  26  is locked in the recess. The spring motor keeps the roller blind  17  tight but it cannot pull the roller blind  17  back into the start position of FIG. 5 because the pegs  26  are locked in the recesses  46 . The roll cover is in its closed position. 
     The user can now pivot the tailgate door  8  downward and lock the tailgate opening  7 . Toward the end of the closing motion, the door  8  comes into contact with the outside ends  63  of the two rams  61  so that the continued closing motion of the tailgate door  8  moves the rams  61  forward in the direction of the disk-like lifting element  54 . This causes the inner end  62 , as shown in FIG. 8, to enter the groove  43 , cross over it and enter the recess  51  behind it. Due to the entering in the recess  51 , the ram touches the surface  57  and turns the disk-like lifting element  54  around its horizontal axis. The disk-like lifting element presses the peg  26  out of the recess  46  with the lower surface against the effect of the spring motor  19 . The retractive force of the spring motor  19  now causes the peg  26  to slide upward on the perpendicular surface  56  on the likewise perpendicular groove side wall until it is touching the ram  61  from below. The peg  26  is located in FIG. 6 above this position in so far that it cannot reach the recess  46  again without pressure from above on the pull bar  25 . 
     When the user opens the tailgate door  8  the next time, the ram  61  is pulled by a return spring (not shown) from the position in FIG. 8 back into the position in FIG. 6 which is identical with the position in FIG.  9 . During this motion, the ram  61  that functioned earlier as a holder for peg  26  leaves the clearance of groove  43 , and the peg  26  can slide to the upper roof-side end of groove  43  under the effect of the retractive force of the spring motor  19 . 
     To prevent sudden movement, i.e., that the rim of the roller blind  17  jumps upward, an appropriate brake device preferably is provided that acts on the winding roller  18 . 
     As was explained in the above function description, the locking device  44  comprises a total of three states. In the first state, as shown in FIG. 6, the respective peg  26  is reliably locked in the recess  46  and the roller blind  17  is fixed in the closed position. The second state of the locking device is shown in FIG. 9 with the complete release of the peg  26  that can move upward in groove  43  without hindrance. The third state shown in FIG. 8 is an intermediate state between the states in FIGS. 6 and 9 and corresponds to a “stand-by” state in which the roll cover  15  is waiting for another opening of the tailgate door  8  in order to reach the position in FIG.  5 . The position of peg  26  and also of the pull bar  25  differs by a few millimeters in the first and the third state in FIGS. 6 and 8. Both positions are closed positions in which the cargo space opening is almost completely closed. In contrast, the position in FIG. 5 is an intermediate position where the rim facing the user is formed by the loop  24  and lifted almost up to the roof so that the cargo space opening is easily accessible from above. 
     If the user wants to open the cargo space completely or if he wants to remove the roll cover  15 , he will first press the rim that is formed by the loop  24  downward so far until the pegs  26  lock again in the corresponding recess  46 . He also can grasp the tube-like loop  24  and pull the roller blind  17  toward himself causing the peg  26  to move from the recess  46  into the receptacle groove  47 . The further movement downward brings the peg  26  into the funnel  49  from which the peg  26  leaves the arresting device  44  completely so that the pull bar  25  can be moved back to the housing  16  on any path. 
     The hooking of the pegs  26  occurs in the reverse order in that these are threaded on both sides in the funnels  49  and brought upward to the position shown in FIG.  6 . 
     FIGS. 10 and 11 show a lateral or perspective view of an exemplary embodiment of the locking device  44  that differs from the embodiment described above in that the pocket is formed with a movable wall in the form of a locking slider  66  that protrudes from the rear in the space of groove  43  above the receptacle groove  47 . 
     The lifting element  54  is seated on the inside of the tailgate door but here it does not have the form of a rotating disk but rather of a rigid arm that is attached on the inside of the tailgate door. The lifting element  54  has on its front end  67  facing away from the tailgate door  8  an offset  68  that turns into a holding nose  69  above it. 
     The function is as follows: 
     When the user brings the roll cover  15  to the closed position, the pegs  26  on both sides move to the respective locking device  44  where they press the locking slide  66  back and reach below it. This locks the respective peg  26  below the locking slider  66  as can be seen in FIG.  11 . When the tailgate door  8  is closed, the lifting element  54  meshes with the peg  26  and presses the peg  26  with simultaneous back push on the locking slider  66  from the clearance of groove  43  so that the peg  26 , as shown in FIG. 10, can reach above the locking slider  66 . Because the nose  69  extends into the movement path of the peg  26 , the peg  26  remains hanging below the nose  69  when the tailgate door  8  is closed. Only another opening of the tailgate door releases the peg  26  on each side so that it can slide through the groove  43  upward to its upper roof-side end. 
     While the position in FIG. 11 shows the first state of the above description, FIG. 10 shows the third state. 
     The receptacle groove  47  and the funnel  49  are present in the same manner. 
     In the exemplary embodiments in FIGS. 6 through 11, the activation of the locking device  44  occurs toward the end of the closing motion of the tailgate door  8 . If this is to occur at the beginning of the closing motion, i.e., in reverse at the end of the opening movement, the solution illustrated in FIGS. 12 through 14 is applied. 
     This construction is similar to that according to FIGS. 6 through 9. 
     The groove  43  of the compulsory guiding device  27  comes from above out of the housing  45 . The receptacle groove  47  runs at its beginning there where it collides with groove  43 , not horizontally but slightly ascending so that a hollow results at  72 . 
     Instead of the disk-like lifting element  54 , a plate-like slide  73  is extended horizontally in a corresponding opening in the housing  45 , shown in perspective in FIG.  13 . The drawing shows the mounting location inside the vehicle. The slide  73  consists of a base plate  74  with two extensions  76  and  78  at its front side  75  facing in the same direction. The extension  78  carries the perpendicular surface  79  that converts into a vertically running even surface  81 . These two surfaces  79  and  81  are the function surfaces of the extension  78 . 
     The essential surfaces of extension  76  are the horizontal even surface  82  on the underside of the extension  76  in FIG. 13 and a perpendicular surface  83  that faces upward. In addition, the extension  76  is bordered at its circumference by a surface  84 . 
     The exact location and effect of the individual surfaces is explained in the function description below. 
     A groove  85  runs parallel to groove  43  in the housing body  45  and is offset from groove  43  toward the tailgate opening  7 . The groove  85  contains an actuating cam  86  with a cam surface  87  at its front sliding sideways. A strong helical spring  89  is supported on a back frontal surface  88  which is supported on the other end at shoulder  91  in the housing  45 . In addition, an elastic and tension resistant cylindrical coupling link  92  is entering in the back frontal surface  88  of the actuating cam  86 . The coupling link  92  is coupled with the tailgate door  8  at its other end (not shown) with a corresponding cam or wedge surface. 
     When the tailgate door  8  is completely opened, the actuation cam  86  is retracted against the effect of the helical spring  89  that is supported in the shoulder  91 . This enables the slide  73  to be pushed forward with the help of a spring  93 . The extension  78  protrudes in this position with its perpendicular surface  79  into the groove  43 . The vertical surface  81  is in the center of the groove  43  and somewhat in front of the beginning of the receptacle groove  47 . At the same time, the extension  76  has vanished out of the clearance of  43  in this position in so far that its side surface  84  is flush with the corresponding wall of the groove  43 . 
     When the roll cover  15  is closed, the peg  26  can, coming from above, reach into the locking device  44  where it first passes by the ineffective extension  83  and then, further down, encounters the perpendicular surface  79  extending into the groove  43 . When the user forcefully pushes the pull bar  25  further downward, the slide  73  is pushed back due to the action of the peg  26  on the perpendicular surface  79  against the effect of the helical spring  93  that prestresses it so that the area of the extension protruding into the clearance of groove  43  vanishes from the clearance. 
     So that this can be accomplished with ease, the surface  79  in the rest position shown in FIG. 12 jumps backward against the corresponding side wall of the groove  43  and causes with the retracting action for the slide  73  the peg  76  to be wedged between surface  79  and the opposite side wall of groove  43 . 
     At the end of the downward motion, the peg  26  gets into the receptacle groove  47  and thus in front of the lower end of groove  43 . The slide  73  can now be moved in the direction of the tailgate opening  7  by the helical spring  93 . The force exerted by the helical springs  93  on the two sides of the tailgate opening  7  is together at least higher than the retractive force than the spring motor  19  can muster. The peg  26  is thus arrested between surface  81  and the walls of the receptacle groove  47  as shown in FIG.  12 . 
     When the user begins to close the tailgate door  8 , the tensile effect at the wire-like coupling link  92  ends soon after leaving the highest opening position of the tailgate door  8  and the helical spring  89  is in position to press the actuation cam  86  down. This causes the cam surface  87  to come into contact with the perpendicular  83 , and due to the resulting cam drive, the force of the spring  89  can shift the slide  73  against the effect of the helical spring  93  which pushes the extension  78  from the clearance of the groove  43 . At the same time, the extension  76  located further up on the front side  75  enters into the clearance as shown in FIG.  14 . The peg  26  is released from the receptacle groove  47  due to the movement of the slide  73  and reaches the groove ascending in perpendicular direction, but remains hanging after a short distance of its movement path at the horizontal surface  82  of the extension. Peg  26  remains here as long as the actuation cam  86  is retracted from the position in FIG. 14 back into the position in FIG. 12 upon opening the tailgate door  8  and the spring  93  can press the slide  73  back. 
     This motion only occurs at the end of the opening motion of the tailgate door  8 . If the user opens the tailgate door  9  only half-ways, the roll cover  15  remains in the closed position. 
     While the compulsory guiding device is a completely closed groove shown in FIGS. 5 through 14, the compulsory guiding device  27  is formed in the exemplary surface embodiment in FIG. 15 by a horizontal straight shoulder surface  95  that starts at the housing  16  and runs to the tailgate opening  7 . The peg  26  of the pull bar  25  is located on this upward facing shoulder surface  95 . The intermediate position is reached with the aid of a stop  95   a  that lifts up from the shoulder surface  95  at the corresponding location and stops during the automatic retraction of the roll cover  15  the corresponding pegs  26 . 
     At the end of the shoulder  95 , i.e., in the vicinity of the tailgate opening  7 , is another locking device  44  illustrated in FIGS. 16 through 18 in different operation positions. 
     The shoulder surface  95  runs with its tailgate-side end into the housing  45  where the shoulder surface  95  becomes a groove  96  in the manner that the lower groove wall  97  aligns with the shoulder surface  95 . The groove  96  opens in the direction to the opposite side wall of the vehicle and continues until almost the tailgate opening  7 , where an end  98  of the groove exits the housing  45 . 
     Close to the end  98 , a boring  99  containing a locking bolt  101  enters through which a spring  102  is prestressed in the direction toward the groove  96  so that a tip  103  of the bolt  101  can protrude a bit into the clearance of the groove  96 . The advancing motion is limited by a flat head  104  that abuts to a corresponding shoulder  105  in the housing  45 . 
     A holder  107  pivoting around an axis  108  is located in a chamber  106  below the groove  96 . The chamber  106  is connected with the groove  96  via an opening  109  in the lower groove wall  97 . It is located in reference to the motion direction of the peg  26  offset from the winding roller  18 . 
     The holder has a buffer plate  111  which is designed to work together with the peg in the manner described below. 
     The holder  107  is prestressed into the position in FIG. 18 by means of the tension spring  112  that touches with its one end the holder  107  and is anchored with its other end at  113  in the housing  45 . The holder  107  abuts with one stop surface  114  to the base of the chamber  106 . In this position the stop surface  114  is retraced from the clearance of the groove  96 . 
     An actuating slide  115  serves the actuating of the holder  107  and the compulsory shift of the peg  26 . The actuating slide  115  has on the same side two extensions  116  and  117 . The extension  16  protrudes through the end  98  of the groove  96  while the extension  117  leads through a boring  118  into the chamber  106 . The extension  117  contains at its inner end a long hole  119  into which the peg  121  attached to the holder  107  glides. 
     The function is as follows: 
     If the user wants to bring the roller blind  15  into the closed position before he closes the tailgate door  18 , he pulls the roller blind  17  with the rim facing him into the direction of the tailgate opening  7 . In that, the pegs  26  slide on the shoulders  95  assigned to them and reach at the end of the slide motion into the grooves  96  of the locking devices  44  mounted at both sides. The pulling motion of the roller blind  17  is continued until the pegs  26  have passed the locking bolt  101  as shown in FIG.  16 . The peg on each side lies then locked behind the tip  103  protruding into the clearance of groove  96  and in front of the inner end of the actuating extension  116 . 
     The passage of peg  26  into this position was possible because the spring  112  had retracted the holder  107  into the chamber  106  which, at the same time, ejected the actuating slide  115  via the guides in the form of peg  121  and the long hole  119  in the direction of the tailgate opening  7 . With locking the peg  26  behind the locking bolt  101 , the first state of the locking device  44  is reached and the roller blind is held safely in the closed position because the retractive force acting on the roller blind  17  cannot overcome the locking force exerted by the locking bolt  101 . When the user now closes the tailgate door  12 , a segment abuts at the actuating slide  115  and presses it forward in the direction of the locking bolt  101 . This presses the peg  26  forward below the locking bolt  101  into the position in FIG.  17 . It cannot leave this position, however, because the advance of the actuation slide  115  over the kinematic connection with the holder  107  has reached its buffer plate  111  from the chamber  106  upward into the motion path of the peg  26 . 
     When the tailgate door  8  is opened again, the tension spring  112  or the force exerted against the buffer plate  111  can push. the holder  107  back and free the motion path for peg  26 . The roller blind  17  then retracts up to the intermediate position to the stop  95   a.    
     In the roll cover for the cargo space or trunk of station wagons, a compulsory guiding device is connected with the front rim of the roller blind; it can be loosened. The compulsory guiding device provides that the roller blind can be moved upward when the tailgate door is opened so that easier access to the cargo space is assured without having to retract the roller blind completely into its housing.