Patent Publication Number: US-8528172-B2

Title: Folding plastic clip for pleated blinds

Description:
The invention relates to a folding plastic clip for pleated fabric blinds that are raised in horizontal pleats by means of a number of parallel raising cords. 
     Pleated blinds are constructed with a number of vertical raising or draw cords, that go from the top rail through loops of a suitable material fitted in the same horizontal height, where it is intended that a pleat shall appear during raising. At the bottom each raising cord is joined to the bottom rail. A known solution brings all the raising cords through the top rail to one side, where they are brought out and connected as a pull-cord by means of a knot subsequent to being all suitably tightened during installation. Raising occurs by pulling downwards on the knot, and in the upper position the joined pull-cord has maximum length. 
     However, there has been a need for operation by means of an endless cord or ball-cord, like e.g. roller blinds and Venetian blinds. In this case the raising cords are in a different known solution wound on drums during raising and unwound during lowering. During the assembly each string must be tightened suitably and fastened to the bottom rail, preserving the desired tightening, so that the weight of the pleated blind is carried equally by the raising cords. 
     The attachment to the bottom rail may occur by means of upwards protruding plastic fitting, which are sewn in place and which may receive the raising cord and retain it. For instance, an oblong plastic flap with a hole may be used, through which the raising cord may be pulled, whereupon it is suitably tightened, and a knot is made on the raising cord. To finish the operation the plastic flap may be folded, and a snap fastener may maintain it in the closed position with the knot hidden. The knot thereby defines the end of the raising cord. Hereby the knot is carried by the fold in the plastic flap, and it is a question of experience to place the knot correctly with respect to a not yet closed plastic flap. A construction of this type is in principle known from DE 37 39 317 A1. In order to obtain an equalized pull in the various raising cords the knot must be placed accurately, and subsequent adjustment requires untying the knot and a different placement. This has turned out to be a slow process in manufacture. 
     This disadvantage is eliminated by means of a plastic clip according to the invention, which is particular in that the plastic clip consists of a carrying part and a locking part, with an interjacent hinge part, that the carrying part has a first and a second slit with an interjacent tongue in the plane of the clip, that the slits open to the same side, and that the raising cord is locked by being brought 1½ times around the tongue. The narrowness of the slits in relation to the thickness of the cord will entail that sufficient friction is obtained to retain the raising cord with a force that may be overcome during fine adjustment, and the winding and closing of the clip will further lock the raising cord in the adjusted position. 
     Such a further locking occurs by cooperating means in the carrying part and the locking part, in that the second slit is secured against expansion by protruding parts that transfer forces from the carrying part to the locking part. Hereby it is completely assured that the raising cords cannot be displaced, even though there is a pulling load on the plastic clip. 
     A further improved locking may be obtained, in that the cooperating means in the carrying part and the locking part cooperate in transferring compressive forces from one part of the carrying part to another part of the carrying part. Hereby the carrying part obtains a strength that fully compensates for a possible reduction in strength caused by the slits. 
     A further advantageous embodiment of the invention is particular in that a hole for introduction of the raising cord has a size so that a carpet needle with the raising cord may pass. This solution is enabled by the fact that there are no tensile forces transferred in the hinge part itself. 
     A further advantageous embodiment of the invention is particular in that the hinge part as well as the tongue are essentially perpendicular to the raising cord. Hereby a particularly compact construction is obtained. 
     A use of the plastic clip is particular in that the raising cord is brought from the outside through a hole placed immediately adjacent the hinge part, that the raising cord is pushed sideways into the first slit and is given a loop around the tongue ending through the second slit, and that the plastic clip is closed, whereby cooperating parts in the locking part and the carrying part assure that the second slit maintains its narrowness and that the end of the raising cord is retained. It is the first loop around the tongue that provides the calibration of the cord length. Similar to prior art the plastic clip has previously been sewn to the bottom rail together with corresponding clips placed at those locations where the raising cords are to end. 
    
    
     
       The invention will be described in greater detail in the following with reference to the drawing, in which 
         FIG. 1  shows a plastic flap according to prior art, with a knot on the raising cord, 
         FIG. 2  shows a clip according to the invention, 
         FIG. 3  shows an open clip according to the invention with a fitted raising cord, and 
         FIG. 4  shows the outside of the carrying part in a closed clip with fitted raising cord. 
     
    
    
     In  FIG. 1  a construction according to prior art is seen. The raising cord  1  is pulled through a hole  2  in a plastic flap  3 , a knot  2   a  (shown dotted) is made on the raising cord, and the upper half of the plastic flap  4  has been buttoned down over the lower half  5  by means of a snap fastener mechanism  6 . The knot  2   a  decides the endpoint of the raising cord. The lower part  7  of the lower part of the plastic flap has previously been sewn into the pleated blind, whereby holes  8  are created. 
     In  FIG. 2  a plastic clip according to the invention is seen. It has the ability to be buttoned together in common with the known clip described above. It consists of a carrying part  50  which has a thinner fixing part  70  which is designed to be sewn into a fold at the lower end of the pleated blind, whereby holes are created as shown at  80 . Near the top the carrying part  50  is connected to a locking part  40 , and these two parts are connected by a hinge part  45  that like the fixing part  70  is made in a thinner material. Holes  46 ,  47  are provided in the hinge part  45  in order to define the bending place, and furthermore a hole  48  of a particular shape has been provided. This shape has the width of the thickness of a raising cord above, in order that it may be centred in the plastic clip, and below it has a width that corresponds to the head of a carpet needle or a similar tool that is used for introducing the raising cord. 
     The carrying part  50  itself has been provided with two slits  51  and  52  and a tongue  53  in between, and the edges of the slits have little protrusions  54 . A pair of holes  55  and a hole  56  as well as a channel  57  with a depth corresponding to the thickness of a raising cord have been provided. 
     The locking part  40  is provided with protrusions  41  that when closed interact with the hole  56  in the carrying part  50 . Furthermore further protrusions  42  closer to the hinge part  45  have been provided; these interact when closed with the pair of holes  55 . On the same side of the plastic clip as the slits  51  and  52  there are provided protrusions  44  and  43  to block the slits when the plastic clip is closed. 
     In  FIG. 3  is shown how the raising cord  1  is introduced into the plastic clip. It has occurred from behind into the hole  48 , whereupon the raising cord is brought to the left and into the slit  51  to the right, past the protrusions  54 . Subsequently the raising cord is again brought from below the clip to the side and into the slit  52 , whereby it appears again at the upper side of the carrying part  50 . The slits  51  and  52  are so narrow that the raising cord is blocked against being pulled out when faced with reasonable forces from the pleated blind. However, a stronger pull in one or the other direction on the plastic clip may shift it on the raising cord for adjustment of the tension of the raising cord. As in the known solution it is desirable that the cord tension is the same for all the raising cords. The end of the raising cord is defined by the first slit. Hereafter the raising cord again brought into the slits  51  and  52 , whereupon the raising cord has been wound 1½ times around the tongue  53  and is now in the bottom of the slits. Finally, the raising cord  1  is brought down through the channel  57 . The installation is ended by folding down the locking part  40  and snapping it in place to the carrying part. Usually one would not consider the capstan effect of 1½ turns to be sufficient, however, by means of the force transmitting protrusions the lock becomes completely secure in its closed condition. 
     The plastic clip in its closed condition is shown from behind in  FIG. 4 . Hereby the slits  51  and  52  are shown facing to the right. It may be seen that the protrusions  42  are pressed into the hole  56  on either side of the raising cord  1 , which is thereby centered and directed into the channel  57 . Correspondingly, the protrusions  43  and  44  block the slits  52  and  51 . This is done because of the strong forces on the plastic clip that may occur during a washing of the pleated blind when the raising cords are solidly fitted to the pleated blind. Hereby it is completely ensured that a loop of the raising cord will not become unhitched from the tongue  53  due to pulling forces. It is hereby enabled that a pleated blind may be washed without removing the raising cords at their lower end (while they must be individually removed from the drums in the top rail). After drying the pleated blind may again be installed, and the upper ends of the raising cords may again be attached to the drums in the top rail, using means that are not described in detail in the present text. These means may advantageously comprise well-defined endings to the raising cord that interact with corresponding well-defined receiving devices in the drums. Hereby it is ensured that the adjusted length is retained for each cord, and hence a pleated blind fitted with clips according to the invention may be washed and re-fitted without the task comprising adjustment of the cord lengths. 
     The protrusions  41  and  42  have an extent in the longitudinal direction of the clip that is so large that compression forces may be transferred from the edges of the holes  55  and  56 , so that the width of the slits are not increased when the raising cord  1  is pulled. Furthermore, forces are transferred to the locking part  40 , which is carried by the hinge part  45  to the same degree as the carrying part and hence contributes to the transfer of forces from the raising cord to the bottom of the pleated blind. There is hence in the closed clip obtained a distribution of the load on the two parts, the carrying part and the locking part, even though the raising cord is only actively engaging the carrying part.