Abstract:
A differentiated beaded chain is provided as an aid for rotating blind slats in a desired rotational direction. The differentiation is realized utilizing beads of differing sizes or textures along a first and second length of the beaded chain. An operator consistently achieves a desired rotational response by pulling one of the first and second lengths. The differentiated beads are identifiable by either touch or sight. Similarly, a differentiated cord is provided for opening and closing blinds or curtains along a vertical or horizontal plane. The cord consists mainly of a first texture and utilizes a second texture along a portion of a length of the cord to provide an operator with a means for identifying an expected result of tugging on either of the first or second textured lengths.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates generally to devices for rotating, opening and closing curtains or slats of blinds, and more specifically to a beaded chain and/or cord having a distinguishing characteristic on at least a portion of the length of the beaded chain or cord that aids a user in rotating blind slats and/or moving blinds or curtains in a desired direction. 
     2. Background 
     Vertical blinds typically use a continuous beaded chain to rotate a series of vertical slats through 180 degrees. By pulling on one side of the chain, the slats rotate in one direction, e.g. to the right, and by pulling on the other side of the chain, the slats rotate in the opposite direction, e.g. to the left. Similarly, cords are utilized in curtains and blinds for opening or closing the curtains or blinds in a horizontal or vertical direction. Existing beaded chains utilize a continuous beaded chain in which all of the beads are of uniform size. This introduces a purely “by chance” event when rotating the slats as there is no way for an operator to know which chain is going to produce the desired result. Similarly, a person desiring to open the curtains or blinds will pull on a side of a cord only to watch the curtains and blinds close. The resulting undesired movement of the blinds or curtain, more often than not, elicits exclamations of frustration along with an overzealous tug on the other side of the cord. 
     In addition to frustrating the operator, pulling the incorrect cord introduces unnecessary wear and tear on the mechanisms of the curtain or blinds. For example, if curtains or blinds are fully opened, a hard tug on the cord stresses the cord because the curtain or blind does not move in response to the downward pulling force. A strong tug on the cord when the curtain or blind is at full extension, either opened or closed, has the potential of snapping the cord, or worse, pulling an entire curtain assembly off of a wall. Similarly, a tug on the incorrect side of the beaded chain, will cause the beaded chain or the gearing to slip which, over an extended time, will degrade the rotational mechanisms of the blinds. 
     FIG. 1 illustrates the cord  4  and beaded chain  2  of the prior art that interact with the control assembly  8  of the curtain or blind slats  6 . In a typical window blind, the beaded chain  2  loops around a sprocket (not shown) that is linked to each slat  6  to rotate the slat  6  through 180 degrees of rotation. By pulling on a first chain side  2   a , the slats  6  rotate in a first direction, and by pulling on a second chain side  2   b  the slats  6  rotate in a second direction. For example, to angle the slats  6  to the left, an operator must tug on the first chain side  2   a , and to angle the slats  6  to the right, the operator must tug on the second chain side  2   b . A tug on the incorrect chain side results in an undesirable position of the slats  6  and/or stress on or slippage of the beaded chain. 
     The beaded chain  2  of the prior art of FIG. 1 does not provide an operator with the opportunity to learn which chain side  2   a ,  2   b  to pull because the beaded chain  2  tends to hang in such a manner that the sides  2   a ,  2   b  of the chain are indistinguishable, For example, the chain sides  2   a ,  2   b  often are touching or are wound around each other, and may not be in predictable locations, e.g. to the front or to the back, due to interference with the blinds, furniture, or the window sill. Further, the typical operator does not have the patience to scrutinize the chain  2  and sprocket (not shown) to determine which side  2   a ,  2   b  to pull. 
     Referring again to FIG. 1, the cord  4  of the prior art typically loops the entire length of the curtains or blinds  6  through the control assembly  8 . A tug on a first cord side  4   a  causes the blinds to open, and a tug on the second cord side  4   b  causes the blinds to close. The cord  4  presents similar problems as presented by the beaded chain  2  in that an operator will inevitably pull the cord side  4   a ,  4   b  that results in an undesirable movement of the curtains or blinds. Thus, a need for a distinguishing beaded chain and cord exists that will assist an operator in determining which chain side  2   a ,  2   b  or which cord side  4   a ,  4   b  to pull to obtain a desired result. 
     SUMMARY OF THE INVENTION 
     It is an advantage of the present invention to provide a differentiated beaded chain and/or cord for opening or closing blinds or curtains. 
     It is a further advantage to provide a differentiated beaded chain and/or cord that enables a user to manipulate blinds or curtains in a desired manner. 
     It is another advantage to provide a differentiated beaded chain or cord that prevents wear and tear on the curtain/blind mechanisms by teaching a user to pull the correct side of the beaded chain and/or cord. 
     It is still another advantage of the present invention to eliminate random outcomes of attempts to open or close curtains, blinds, or slats. 
     A differentiated beaded chain of an exemplary embodiment of the present invention is constructed of at least two different bead sizes that are distinguishable by touch and/or by sight. In an exemplary embodiment, a first portion of the beaded chain utilizes a standard bead size #8 that has a diameter of approximately 0.156 inches (3.96 mm). The remaining portion of the chain utilizes a second bead size #13 that has a diameter of approximately 0.250 inches (6.35 mm). In other embodiments the bead sizes of the first portion and the remaining portion may vary as long as the bead sizes are compatible with a curtain or blind sprocket. The bead sizes #8 and #13 of the exemplary embodiment present advantages of compatibility with existing sprockets as well as chain strength. The differentiated beaded chain of the exemplary embodiment is installed on the beaded chain drive sprocket of the curtain and/or blind unit at the time of manufacture. 
     Beaded chains utilized for rotating a sprocket-type assembly have a first length for feeding into one side of the sprocket-type assembly and a second length for feeding out of a second side of the sprocket-type assembly. In a looped beaded chain the sprocket assembly defines one end of the loop, and the first and second length each define on half of the loop length. In an exemplary embodiment, the differentiated beaded chain is positioned such that a first bead size portion is located along the first length, and a second bead size portion is located along the second length when the blinds are at a predetermined initial position, e.g. at a 90 degree open position. Thus, to rotate the blinds to the right, or to a 180 degree closed position, the operator pulls on the first bead size portion. To rotate the blinds to the left, or back through the 90 degree position to the 0 degree closed position, the operator simply pulls on the second bead size portion. 
     The repeated manipulations of the blinds, teaches an operator that a tug on a large beaded chain length produces a certain rotation of the blinds, and a tug on a small beaded chain length produces an opposite rotation of the blinds. The operator can easily distinguish the beaded chain sizes by sight or feel, and thus, the operator will consistently achieve the desired rotation of the blind slats. The known result of a tug on a large or small beaded chain length will prevent wear and tear on the sprocket-type assembly that may result due to slippage of the beaded chain. 
     The beaded chain of the exemplary embodiment utilizes at least two bead lengths of metal-based beads that vary according to size to provide a sight and feel differentiation. In an alternative embodiment, the first and second bead length may utilize beads having varying texture, wherein one of the first and second bead lengths is coated or rubberized to provide a sight and feel differentiation. This latter embodiment may employ either a beaded chain of a single bead size, or a beaded chain of two bead sizes wherein the coating or rubberization provides an added means for differentiating a length of beads. 
     The exemplary embodiment of the present invention may be incorporated into existing beaded chains having a single size of bead throughout the entire chain loop. An exemplary method of retrofitting an existing beaded chain includes the step of replacing one of the first or second bead lengths with a beaded chain length having a bead size that is either smaller or larger than that of the existing beaded chain. The bead size of a typical existing beaded chain is size #8, or 0.156 inch diameter (3.96 mm). Thus, the step of replacing one of the first or second bead lengths includes splicing the existing beaded chain adjacent a first end and a second end, and inserting a #13 beaded chain length utilizing splicing links. In the exemplary embodiment, a standard #10 splicing link having a length of approximately 0.531 inches (13.49 mm) and a diameter of 0.25 inches (6.35 mm) readily accepts the #8 bead and the #13 bead. The splicing links of the exemplary embodiment are accepted into the sprocket assembly, and thus, the splicing links do not interfere with the rotation of the sprocket. In an alternate embodiment, a coated beaded chain is utilized as the replacement beaded chain length to provide differentiation of the chain lengths. 
     Certain sprocket assemblies may have close tolerances that only accept the bead size of the originally-installed beaded chain. Alternatively, it may be desirable to utilize the existing beaded chain, for example size #8, so as not to affect the existing operating mechanism of the slat rotation. An exemplary method for retrofitting close tolerance beaded chain assemblies includes the steps of fully rotating the slates by pulling on a first side of the chain, and splicing in the differentiated bead length along a second side of the chain as described above. Thus, since the chain has rotated through the sprocket assembly to a fully rotated position, the splice will not be pulled through the sprocket. 
     In another embodiment, the beads of the originally-installed beaded chain may be mid-sized and not well-suited for differentiation purposes. For example, the installed bead size may be size #10 having an approximate diameter of 0.178 inches (4.52 mm), such that a replacement beaded chain length having either size #8 or size #13 beads will not provide a sufficient size differentiation. A method for retrofitting a mid-sized beaded chain includes the steps of rotating the blind slats to an initial position of 90 degrees, splicing a first smaller beaded chain along a first length utilizing a first splicing link, splicing a second larger beaded chain along a second length utilizing a second splicing link, and connecting the first smaller beaded chain to the second larger beaded chain utilizing a third splicing link. For sprocket assemblies having close tolerances, the above method further includes the step of maintaining a sufficient length of originally-installed beaded chain length wrapped around, and adjacent, the sprocket such that the originally-installed beaded chain rotates the slats to a fully closed position to either the left or to the right. 
     The exemplary embodiment of the present invention may also utilize a differentiated cord to aid in opening or closing curtains or blind slats along a vertical or horizontal plane. The differentiated cord has a first length and a second length that extends below a valence level (or the opening/closing mechanism), and that may be defined when the curtains or blinds are fully opened or closed. A cord length of a different texture may be spliced along one of the first or second lengths during or after manufacture. For example, a cord having a smooth texture for the bulk of length and a “hairy” texture for the spliced-in length will provide sufficient differentiation for an operator. In an exemplary embodiment, if the hairy length of the cord comprises the first length when the curtains or blinds are fully closed, then the operator knows that tugging on the smooth length of the cord will open the blinds/curtains, and tugging on the hairy length of the cord will re-close the blinds/curtains. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be better understood from the following detailed description of a preferred embodiment of the invention, taken in conjunction with the accompanying drawings in which like reference numerals refer to like parts and in which: 
     FIG. 1 is an illustration of the prior art beaded chain and cord; 
     FIG. 2 a  is an illustration of a differentiated beaded chain of a preferred embodiment when the blind slats are fully rotated in a first direction; 
     FIG. 2 b  is an illustration of the differentiated beaded chain in an initial position of rotation; 
     FIG. 2 c  is an illustration of the differentiated beaded chain when the blind slats are fully rotated in a second direction; 
     FIG. 3 a  is an illustration of a differentiated cord of a preferred embodiment when the blinds are closed along a horizontal plane; 
     FIG. 3 b  shows the positioning of the differentiated cord when the blinds are in an initial opened position along a horizontal plane; 
     FIG. 4 is an illustration of a method of retrofitting a beaded chain; 
     FIG. 5 is a cross section of a differentiated beaded chain that is installed at the time of manufacture of a blind; and 
     FIG. 6 is a cross section of a retrofitted beaded chain. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 2 a ,  2   b , and  2   c  illustrate the differentiated beaded chain of vertical blinds of a preferred embodiment of the present invention. As shown in FIG. 2 b , the vertical blind assembly includes slats  6  that are rotatable in a first direction R 1  and a second direction R 2 . The slats  6  are rotated by applying a force F 1  on a first chain side  10  of a beaded chain  20  or a force F 2  on a second chain side  12  of a beaded chain  20 . The beaded chain  20  rotates a sprocket-type assembly  22  which, in turn, rotates the slats  6  by means of a linkage assembly  24 . As shown in FIG. 2 b , the beaded chain of a preferred embodiment comprises a first chain side  10  of larger-sized beads and a second chain side  12  of smaller-sized beads. The beaded chain is positioned to have all large beads on the first chain side  10 , and all small beads on the second chain side  12  when the slats  6  are positioned in an initial position. The initial slat position of a preferred embodiment is an open position of 90 degrees. A position of 0 degrees, as shown in FIG. 2 a , closes the slats  6  with a first side of the slats facing the operator, and similarly, a 180 degree position, as shown in FIG. 2 c , closes the slats with a second side of the slats  14  facing the operator. In alternate embodiments, the initial position may be chosen as desired, for example, a closed position of either 0 degrees or 180 degrees. 
     In a preferred embodiment, as shown in FIG. 2 b , a downward force F 1  on the first chain side  10  rotates the blinds in a first direction R 1 , and a downward force F 2  on the second chain side  12  rotates the blinds in a second direction R 2 . FIGS. 2 a - 2   b  are for illustrative purposes, only, and the direction of rotation R 1 , R 2  in response to downward forces F 1 , F 2  may be switch in other embodiments of the present invention. Further, the sprocket assembly  22  of alternate blind systems may be positioned so that the chain hangs with a first chain side  10  behind or in front of a second chain side  12 . 
     The beaded chain  20  of the present invention provides a user a means for opening and closing the blind slats in a predictable rotation R 1 , R 2 . In a preferred embodiment as illustrated in FIG. 2 b , a user learns, through repeated use, that a downward pull F 1  on larger beads of a first chain side  10  produces a predictable result of the blinds rotating in a first rotational direction R 1 , for example, to the left. Referring to FIG. 2 a , when a user wishes to rotate the blind slats open, he or she may utilize a number of sight and touch cues from the beaded chain  20 . A visual cue presented by the beaded chain  20  of FIG. 2 a  is that the larger beads and smaller beads are not positioned evenly on one or the other side of the beaded chain  20 . Thus, the beaded chain  20  prompts the user to pull on the second chain side  12  of smaller beads in order to even the beads and, thereby, open the slats  6 . Alternatively, the user is simply prompted by the bead size, and learns, through repeated use, that rotation of the slats  6  in the R 2  direction, for example, to the right, requires a downward force applied to the smaller beads of the second chain side  12 . 
     The beaded chain  20  also provides touch cues. A user may grab both chain sides  10 ,  12 , and, by the distinguishing feel of the beads, may quickly chose the larger beaded chain section  10  to rotate the blinds to the left, or alternately chose the smaller beaded chain section  12  to rotate the blinds to the right. The use of different size beads in the beaded chain  20  allows the user to predictably manipulate the blind slats  6  by feel during periods of low light levels, such as at night, dusk or dawn without having to turn on lights. 
     The beaded chain of the preferred embodiment may be installed at the factory, or retro-fit to an existing blind assembly. FIG. 5 illustrates a beaded chain section  100  of a pre-installed beaded chain of a preferred embodiment of FIG. 2 b . A series of smaller beads  102  are linked by small linking segments  104 . Similarly, a series of larger beads  106  are linked by large linking segments  108 . A smaller bead  102  may be utilized to directly linked the smaller bead section to the larger bead section by placing a smaller bead  102  within a larger bead  106 . During installation, the beaded chain section  100  is positioned on the sprocket assembly in a desired initial position. 
     The preferred embodiment of a pre-installed beaded chain  100  utilizes a small bead  102  having a #8 bead size of approximately 0.156 inches (3.96 mm), and a large bead  106  having a #13 bead size of approximately 0.250 inches (6.35 mm). In another embodiment of a pre-installed beaded chain, a #8 small bead  108  segment is directly linked to a large bead  106  segment having a #10 bead size of approximately 0.178 inches (4.52 mm). Other embodiments may utilize other bead sizes wherein the large bead  106  and small bead  102  are sufficiently differentiable by either sight or touch. 
     FIG. 4 illustrates a retrofitted beaded chain  40  having an originally-installed beaded chain  44  utilizing size #10 beads. To provide a maximum differentiation of beaded chain sections, a #8 bead section  44  is spliced to the originally-installed beaded chain  44  utilizing a first splicing link  50  on a first chain side  54 , and a #13 bead section  46  is spliced to the originally-installed beaded chain  44  utilizing a second splicing link  48  on a second chain side  56 . The first chain side  54  is then spliced to the second chain side  56  utilizing a third splicing link  52 . In a preferred embodiment, the splicing links  48 ,  50 ,  52  are a size #10 splicing link having a length of approximately 0.531 inches (13.49 mm) and a diameter of 0.25 inches (6.35 mm). 
     FIG. 6 illustrate retrofitted beaded chain  120  having a small bead  102  chain section connected to a large bead  106  chain section utilizing a splicing link  122 . The splicing link  122  may be any size that will accept two different bead sizes. The choice of splicing link  122  is limited by the diameter D and the hole  124  that provides an exit for linking segments  104 ,  108 . A hole  124  that is too large will permit a small bead  102  to slip out of the splicing link  122 . The splicing link  122  size may also be limited by the configuration of a sprocket assembly  22 . Referring again to FIG. 4, a sprocket assembly  22  having tolerances specific to a pre-installed bead size  44  may not readily accept either a splicing link  48 ,  50  or a larger bead size  46 . In such circumstances, the retrofitted beaded chain  40  must maintain a sufficient length of the original beaded chain  44  to permit a full rotation of the blinds to the right or to the left. 
     A method of retrofitting a beaded chain  40  of a preferred embodiment, as shown in FIG. 4, includes the steps of rotating the blind slats  6  to a desired initial position of 90 degrees, removing a portion of the original bead section below a first end bead  58  and a second end bead  60 , splicing a first beaded chain section  44  on a first chain side  54 , splicing a second beaded chain section  46  on a second chain side  56 , and connecting the first chain side  54  to a second chain side  56 . In an alternate embodiment, wherein the original bead section  44  utilizes a sufficiently small or large bead size, it is necessary to replace only one of the first side  54  or second size  56  of the beaded chain  44  with a beaded chain section having a bead size that is easily differentiated from the bead size of the original bead section  44 . 
     Referring to FIGS. 2 b , an alternative embodiment of the beaded chain  20  of the present invention utilizes a first chain side  10  having beads that are texturally differentiated from the beads of a second chain side  12 . The texture of the first and second chain sides  10 ,  12  are distinguishable by both look and feel. In an alternate embodiment of the present invention, one of the first and second chain sides  10 ,  12  utilizes a rubberized coating, colored or clear, on each bead to affect a change in texture. The embodiments of the present invention, as illustrated in FIGS. 2 b  and  4 , also may be implemented for beaded chains manufactured from extruded plastic. 
     FIGS. 3 a  and  3   b  illustrate the present invention as applied to cords for opening and closing curtains or blinds. FIG. 3 b  shows blinds  6  in an initial open position. A differentiated cord  30  has a first cord segment  18  that is texturally different from a second cord segment  16 . An operator must apply a downward force F 3  on the first cord segment  18  to close the blinds in a horizontal direction, as shown in FIG. 3 a . To open the blinds  6 , a downward force F 4  is applied to the second cord segment  16 . Textural differences may be realized in a number of ways including the use of a smooth segment and a fuzzy segment of cord, the use of a smooth segment and a rubberized segment of cord, the use of a smooth segment and a knotted segment, and the use of any other combination thereof. 
     The differentiated cord or beaded chain teaches an operator, through repeated use and observation of resulting movement of the curtain and blinds, to predictably open blinds or curtains and rotate blind slats. A predictable result provides a means to avoid operator frustration and wear and tear on the opening mechanics  8  of the blinds and/or curtains. 
     Although a preferred embodiment of the invention has been described above by way of example only, it will be understood by those skilled in the field that modifications may be made to the disclosed embodiment without departing from the scope of the invention, which is defined by the appended claims. For example, the invention also is applicable for other devices utilizing cords, beaded chains and sprocket-type devices rotated by a beaded chain.