Abstract:
An improved equalizer for gripping two or more cords of a shade is described. The equalizer of the invention comprises a molded body member having a tapered inner channel into which a molded insert member fits. The cords are placed within the channel through a gap formed in one wall of the body member, and are clamped against a rear wall thereof by the insert member. As the insert member is inserted more fully into the body member, the cords are compressed between the insert and the rear surface of the body member, and the insert is permanently wedged into the body member.

Description:
FIELD OF THE INVENTION 
     This invention relates to an improved cord equalizer. More particularly, this invention relates to an improved equalizer for firmly gripping two or more control cords of a window shade. 
     BACKGROUND OF THE INVENTION 
     Cord equalizers are conventionally used in window shades and blinds of all kinds. A cord equalizer for a shade has several functions which provide constraints on its design. The cord equalizer is used to grip two or more shade control cords, to allow their convenient operation as one, to keep the shade level when it is pulled to the headrail from which it is normally suspended and to keep the cord from tangling. The cord equalizer is also used to provide a stop for the cord as the shade is lowered to the bottom of its travel; that is, the cord equalizer abuts the cord locking mechanism provided in the headrail to prevent further lowering of the shade. 
     Various known types of cord equalizers suffer from various combinations of defects. Some known cord equalizers have been extremely complicated and difficult to install. For example, equalizers with closed housings require threading of the cords through the housing. Others grip the cords in such a way as to damage it, leading to premature failure. Other types of cord equalizers are difficult to adjust in order to provide equal pull on the cords, e.g., those to which the cords are fixed by separately tied knots. Other cord equalizers tend to fail prematurely due to wear. Improvement in cord equalizers is therefore needed. 
     SUMMARY OF THE INVENTION 
     The present invention satisfies the needs of the art mentioned above by provision of an improved cord equalizer which allows easy insertion of the cords and which locks the cords in place by compressing them against a flat surface, thus not over-stressing the cords or urging them against a sharp edge or the like. The members of the equalizer are not subject to wear. 
     More specifically, the cord equalizer of the invention comprises a first molded body member and a second insert member. The insert is locked against the body member on the wedge principle. A wedge-shaped channel extends through the body member, growing generally narrower from an entrance to an exit. The cords are disposed in the channel, behind the insert. As the insert is pushed into the cavity, it is urged against the cords, compressing them against the body member. As one pulls downwardly on the equalizer, that is, exerting tension on the cords to control the shade, the insert is drawn more tightly into the body member. On the other hand, the insert can be removed from the body member simply by pulling the cords in the opposite direction. This allows the cord equalizer to be readily adjusted. 
     The body member comprises a U-shaped channel wherein flanges are formed on the legs of the U, extending toward one another. A space is left between the flanges through which the cords can be easily placed in the interior of the body member. The side walls of the channel are tapered from an entrance end of the channel to an exit end, providing wedging surfaces. The insert fits beneath the flanges, and is of hat-shaped cross-section, having a center section extending outwardly between the flanges, thus providing convenient alignment and a neat appearance. Projections from the center section are retained beneath the flanges of the body member. When the assembly is complete, the center section is flush with the outer surface of the body member, and the ends of the insert are flush with those of the body member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood if reference is made to the accompanying drawings, in which: 
     FIG. 1 shows a front view of a typical shade employing the equalizer according to the invention; 
     FIG. 2 shows a perspective view of the equalizer of the invention, in a fully assembled configuration; 
     FIG. 3 shows a cross-sectional view through the equalizer of the invention, showing the insert member being inserted into the body member; and 
     FIG. 4 shows a view corresponding to FIG. 3 with the insert fully inserted into the body member, and is equivalent of a view taken on the line 4--4 of FIG. 2. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a front view of a conventional shade or blind member incorporating the equalizer of the invention. The shade comprises an expandable and collapsible shade or blind member 10 formed according to any one of a number of teachings, suspended from a headrail 12 and optionally having a foot rail 14 at its lower extremity. Two or more cords 16 (in some cases up to eight parallel cords) pass upwardly from the foot of the shade member or from the foot rail 14 up into the headrail 12, and thence by guides 18 toward a locking mechanism 20 at one end of the headrail. The cords are moved from a locked position A in which they hang when released to a released position B in order to control the cords. The user may grasp the cords 18 directly, grasp a tassel 24 typically affixed to the ends of the cords, or grasp an intermediate equalizer 22 according to the invention. 
     In the preferred embodiment, the locking mechanism 20 is &#34;crash-proof&#34;, meaning that if the cords are released the locking mechanism 20 will engage the cords 18 and prevent the shade member 10 from crashing to its lowest extent. The travel of the shade member 10 is limited by the relative position of the equalizer 22 on the cords 18, which abuts the locking mechanism 20 at the full travel of the shade member. The equalizer must therefore be firmly affixed to the cords such that it does not weaken them, and such that it is not separated from the cords when it abuts the locking mechanism 20. 
     The equalizer comprises a first molded body member 30 and a second molded insert member 32. The equalizer 22 is shown fully assembled in FIGS. 2 and 4 and at an intermediate stage of its assembly in FIG. 3. As indicated, the body member 30 is generally tapered, and defines a U-shaped channel with flanges 30d extending toward one another from the legs of the U, partially closing the channel. The channel is thus defined by first and second side walls 30a and 30b, a third rear wall 30c, and a partial fourth wall which comprises first and second flanges 30d which approach each other from the outer ends of the side walls 30a and 30b. 
     The insert 32 comprises an elongated member which is generally of hat-shaped cross section, having a central portion 32a and first and second projections 32b and 32c. As can be seen in FIG. 2, when the insert 32 is fully inserted into the body member 30, the center section 32a is flush with the outer surface of the fourth wall of the body member 30, thus providing a neat appearance. The projections 32b and 32c fit beneath the flanges 30d. As shown by FIGS. 3 and 4, the insert 32 also comprises a transverse ridge 32d. 
     FIGS. 3 and 4 show that the first and second walls 30a and 30b of the body member 30 become more narrow from the entrance end 34 of the body member to the exit end 36, so that the inside surface of the third wall 30c is farther from the inner surface of the flanges 30d at the entrance end 34 of the channel than at the exit end 36. In particular, the rear wall 30c may be formed to have a gentle bend 30f therein as shown. The cords 18 are disposed between the insert and the rear wall 30c of the body. Thus, when the insert 32 is inserted from the entrance end and moved axially toward the exit end, the insert 32 compresses the cords 18 against the rear wall 30c of the body member 30. In particular, the ridge 32d urges the cords 18 against the inner surface of rear wall 30c of the body member 30. As shown in FIG. 4, the ridge 32d eventually tightly compresses the cords 18 against the rear wall 30c, firmly gripping them and securing the equalizer 22 in place on the cords 18. 
     The bend 30f in the inner surface of the rear wall 30c effectively defines the point at which the ridge 32d first urges the cords firmly against the rear wall 30c. Bend 30f separates the inner surface of the rear wall 30c into two sections, a first section which is inclined with respect to the inner surfaces of the flanges 30d, and a second section which is parallel thereto. When the insert 32 is fully inserted into the channel, the ridge 32d is juxtaposed to the second parallel section of the inner surface of the rear wall. Provision of bend 30f limits the axial distance through which the insert member 32 must be moved with the cords tightly compressed. This expedient controls the force required to move the insert 32 with respect to the body member 30 to reach the position of FIG. 4. 
     It will be appreciated that the shape of the insert is chosen with respect to the spacing of the inner surfaces of the flanges from the inner surface of the third rear wall such that the insert eventually reaches the final position shown in FIGS. 2 and 4, in which the ridge 32d confines the cords against the inner surface of the rear wall 30c. 
     Friction between the insert 32, the cords 18 and the body 30 is normally sufficient to retain the equalizer on the cords, particularly when (as is normal) the equalizer is installed with the entry end down. In this position, the user tends to tighten the grip of the equalizer on the cords by exerting tension on them by grasping the equalizer to control the motion of the shade. However, at any time, the equalizer can be freed from the cords by pulling the equalizer upwardly with respect to the cords. This frees the insert 32 from the body 30. 
     In the embodiment shown, the rear and partial fourth walls of the body member have parallel sides, that is, the tapered first and second walls 32a and 32b are parallel to one another, but this need not necessarily be the case. Making the entry end of the channel somewhat wider than the exit end eases insertion of the insert. The insert may also be tapered, and the third and fourth walls parallel. 
     The materials of the body member and insert are normally identical so that they can be formed in a single molding step. The members should be formed of some readily molded, inexpensive, friction and heat resistant plastic material. Other details of the manufacture of the equalizer of the invention are considered to be within the skill of the art. 
     While a preferred embodiment of the invention has been disclosed in detail, this is not to be considered as a limitation thereon but only as exemplary thereof. The invention should therefore not be limited by the above disclosure, but only by the following claims.