Patent Publication Number: US-5890529-A

Title: Dual action retractable cord take-up reel

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a retractable take-up reel. More particularly, the present invention relates to a dual action retractable cord take-up reel for adjusting a position of a window covering. 
     2. Description of Related Art 
     Conventional window covering designs employ cord loops for adjusting a position of the window covering, e.g., for raising and lowering the window covering. A cord loop is typically wound around a cord drive wheel, which is connected to a drive shaft. The drive shaft is connected to the window covering. Pulling on one side of the cord loop causes the cord drive wheel to rotate in a first direction, which in turn causes the drive shaft to rotate in the first direction. The rotation of the drive shaft in the first direction causes the window covering to move in the first direction, thus, for example, raising the window covering. Pulling on the other side of the cord loop causes the cord take-up wheel to rotate in a second direction, opposite from the first direction, which in turn causes the drive shaft to rotate in the second direction. The rotation of the drive shaft in the second direction causes the window covering to move in the second direction, thus, for example, lowering the window covering. In this manner, the window covering is raised or lowered by pulling on opposite sides of the cord loop. 
     Attempts have been made to eliminate cord loops, which can get caught on objects. For example, motorized window coverings have been introduced which eliminate cord loops. Such motorized window coverings are complex and expensive. 
     Another attempt employs multiple cords with individual tassels. For example, a tassel has been developed which provides a breakaway method of holding multiple cords together until a predetermined weight causes them to separate. According to this technique, the ends of two cords are each connected to cylindrical pieces that snap together to form one continuous cylindrical piece, forming a &#34;loop&#34; between the two cords. If the loop gets caught on an object, the weight of the object causes the cylindrical pieces to unsnap. A problem with this technique is that the cylindrical pieces add to the overall size, cost, and complexity of the window covering and are unsightly. 
     There is thus a need for a system that adjusts a position of a window covering without a cord loop simply, unobtrusively, and at low cost. 
     OBJECTS AND SUMMARY 
     It is an object of the present invention to provide a simple, inexpensive, and unobtrusive apparatus for adjusting a position of a window covering without a cord loop. 
     According to one embodiment of the present invention, this objective is met by a retractable cord take-up reel. The take-up reel comprises a drive shaft and a first reel mounted on the drive shaft. The first reel has a central opening and a first side. A drive shaft gear is mounted on the drive shaft, and the drive shaft is rotated by rotation of the drive shaft gear. A first drive gear is mounted on the drive shaft between the first reel and the drive shaft gear. The first drive gear has a central opening and a first side facing the first reel and a second side facing the drive shaft gear. One of the first side of the first reel and the first side of the first drive gear has an angled surface, and the other of the first side of the first reel and the first side of the first drive gear has a cog facing the one first side. The one first side has two steps for engaging the cog. A first one of the steps is at a low location on the angled surface, and a second one of the steps is at a high location on the angled surface. When the cog is engaged with the first step, the first drive gear is engaged with the drive shaft gear. When the cog is engaged with the second step, the first drive gear is not engaged with the drive shaft gear. A cord is wound on the first reel, and when the cord is pulled, the first reel rotates so that the cog engages with the first step, and the drive shaft is driven in a first direction. 
     According to one embodiment of the present invention, the retractable cord take-up reel further comprises a second reel and a second drive gear. The second reel and the second drive gear are configured similar to the first reel and the first drive gear and are mounted on the drive shaft on an opposite side from the first reel and the first drive gear. A cord is wound on the second reel so that when the cord on the second reel is pulled, the drive shaft is driven in a second direction that is opposite the first direction. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The objects and advantages of the invention will be understood by reading the following detailed description in conjunction with the drawings in which: 
     FIG. 1 illustrates a dual action retractable cord take-up reel according to one embodiment of the present invention; 
     FIG. 2 shows a cross-sectional view of an interior portion of a housing and components enclosed in the housing according to one embodiment of the present invention; and 
     FIG. 3 shows an exploded view of angled surfaces of a drive gear and a cord take-up wheel according to one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     According to one embodiment of the present invention, a dual action retractable cord take-up reel is provided for adjusting a position of a window covering. The retractable cord take-up reel can be attached to the hardware system of various types of window coverings to adjust a position of the window covering, for example, to raise, lower, or tilt the window covering. The position of the window covering is adjusted by pulling on one of two cords. 
     The retractable cord take-up reel is preferably arranged in two halves, one of which is substantially a mirror image of the other. 
     FIG. 1 illustrates a dual action retractable cord take-up reel for adjusting a position of a window covering according to one embodiment of the present invention. The retractable cord take-up reel comprises two cord take-up wheels 200, 200&#39;. Each of the cord take-up wheels 200, 200&#39; includes a reel portion 201, 201&#39; for receiving a pull cord 400, 400&#39;. A first cord 400 is wrapped around the reel portion 201 of the cord take-up wheel 200, and a second cord 400&#39; is wrapped around the reel portion 201&#39; of the cord take-up wheel 200&#39;. Each of the cord take-up wheels 200, 200&#39; also includes an internal cavity for receiving the respective drive gears 500, 500&#39;. The internal cavity of the cord take-up wheel 200 includes a sloping or angled surface 210 that is intended to cooperate with an angled surface 515 on the drive gear 500. Similarly, the internal cavity of the cord take-up wheel 200&#39; includes a sloping or angled surface (not shown) that is intended to cooperate with an angled surface 515&#39; on the drive gear 500&#39;. 
     Drive gears 500, 500&#39; fit inside the internal cavities of the cord take-up wheels 200, 200&#39;, respectively. Each of the drive gears 500, 500&#39; includes the previously mentioned angled surfaces 515, 515&#39; on one side thereof, and teeth 520, 520&#39; on an opposite side thereof. 
     The angled surfaces 515, 515&#39; include cogs 505, 505&#39; for coacting with steps on the angled surfaces of the cord take-up wheels 200, 200&#39;, respectively. In FIG. 1, only one step 205a is illustrated. However, there are preferably two steps on each of the angled surfaces of the cord take-up wheels 200, 200&#39; 
     A drive shaft 600 is arranged through central openings in the drive gears 500, 500&#39; and through the internal cavities and central openings in the cord take-up wheels 200, 200&#39;. The drive shaft 600 includes an end 630 having flat surfaces to facilitate attachment to a window covering mechanism. Of course, this end 630 may, alternately, be some other shape or design suitable for attachment to a window covering mechanism in any other conventional manner. 
     The drive shaft 600 includes a gear 610 having teeth 620a, 620b facing the drive gears 500, 500&#39;, respectively. The teeth 620a on the drive shaft gear 610 match the teeth 520 on the drive gear 500, and the teeth 620b on the drive shaft gear 610 match the teeth 520&#39; on the drive gear 500&#39;. 
     The drive gears 500, 500&#39; include, on respective surfaces facing the drive shaft 600, flippers 510a, 510b and 510a&#39;, 510b&#39;, respectively. These flippers bias the drive gears 500, 500&#39; away from the drive gear 610 and toward the cord take-up wheels 200, 200&#39;, respectively, as described in more detail below. 
     Coupled to a side of the cord take-up wheel 200 opposite the side facing the drive shaft 600 is a spiral-shaped recoil spring 300. The recoil spring 300 includes an end 310 that is attached to the cord take-up wheel 200 through a slot 220 in the cord take-up wheel 200. The recoil spring 300 may alternately be attached to the cord take-up wheel 200 by other means, e.g., a pin or a snap. The recoil spring 300 includes another end 320 that is attached to an interior surface of the housing 100. The end 320 may, for example, fit into a groove in the housing. Alternately, the recoil spring 300 may be attached to the housing by means such as a screw. Although only one recoil spring 300 is shown, another spiral-shaped recoil spring is coupled in a similar manner to the side of cord take-up wheel 200&#39; opposite the drive shaft 600 through a slot 220&#39; on the cord take-up wheel 200&#39;. 
     A housing 100 includes an internal cavity 120 for holding the drive shaft 600, the drive gears 500, 500&#39;, the cord take-up wheels 200, 200&#39;, and the recoil springs. End plates 110, 110&#39; are mounted to respective ends of the housing. The housing 100 is preferably small in relation to the window covering so as to easily fit into a head rail and thus be unobtrusive. For example, the housing can be 1&#34; square. 
     FIG. 2 shows a cross-sectional view of an interior portion of the housing 100 and components enclosed in the housing according to one embodiment of the present invention. For ease of illustration, only the drive shaft 600, the drive gear 610, and the drive gear 500 are shown enclosed by the housing 100. 
     In a central part of the cavity 120 is a partial wall 130 that includes an opening in a center thereof for receiving the drive shaft gear 610. The flippers 510a, 510b, 510a&#39;, and 510b&#39; are arranged so that the free end of each flipper rests against the partial wall 130 and biases the respective drive gear 500, 500&#39; away from the drive shaft gear 610 and toward the respective cord take-up wheel 200, 200&#39;. 
     The angled surface 515 of the drive gear 500 slopes upward toward the cord take-up wheel 200. This is shown in more detail in FIG. 3 which shows an exploded view of the angled surfaces of the drive gear 500 and the cord take-up wheel 200 according to one embodiment of the present invention. 
     Referring to FIG. 3, the angled surface 515 slopes upward toward the cord take-up wheel 200 at an angle of β degrees from the vertical. Similarly, the angled surface 210 of the cord take-up wheel 200 slopes downward toward the drive gear 500 at an angle of β degrees from the vertical. Thus, the angled surface 210 of the cord take-up wheel 200 &#34;corresponds to&#34; the angled surface 515 of the drive gear 500 in that both angled surfaces slope at the same angle from the vertical. In a preferred embodiment, the angle β is shallow, in the range of 3°-6°. It is not necessary for the angle of the surface 515 to equal the angle of the surface 210. 
     The angled surface 210 has a step 205a at a high portion and a step 205b at a low portion. These steps 205a,b coact with the cog 505 as described in more detail below. 
     Although not shown, the angled surface 515&#39; slopes, in a similar manner, upward toward the cord take-up wheel 200&#39;, and an angled surface of the cord take-up wheel 200&#39; slopes downward toward the drive gear 500&#39;, the angled surface 515&#39; of the drive gear 500&#39; corresponding to the angled surface of the cord take-up wheel 200&#39;. Also, the angled surface of the cord take-up wheel 200&#39; includes two steps that coact with the cog 505&#39; in a similar manner as the steps 205a,b coact with the cog 505. 
     Referring again to FIG. 1, when the cord 400 is pulled, the cord take-up wheel 200 rotates in a first direction a. At this time, the flippers 510a,b urge the drive gear 500 away from engagement with the gear 610. Accordingly, the drive gear 500 does not rotate on the drive shaft 600 until the step 205a on the angled surface 210 of the cord take-up wheel 200 comes to rest against the cog 505. The step 205a is on a high location on the angled surface 210. Accordingly, when the cog 505 abuts the step 205a, the drive gear 500 is pushed into engagement with the gear 610. This causes the teeth 520 on the gear 500 to engage the teeth 620a on the drive shaft gear 610, causing the drive shaft 600 to rotate in the first direction a. In this manner, the force caused by pulling on the cord 400 is translated directly to the drive shaft 600, causing it to rotate in the first direction a. 
     When the cord 400 is released, it is then recoiled onto the cord take-up wheel 200, which is driven by the recoil spring 300 in a second direction b, opposite the first direction, to its original position. As the cord take-up wheel 200 turns in the second direction b, the drive gear 500 remains in place in engagement with the drive shaft gear 610 until a second step 205b comes to rest against the cog 505. The second step 205b is at a low location on the angled surface 210. Accordingly, at this time, the flippers 510a,b push against the wall 130 to disengage the drive gear 500 from the gear 610. This causes the drive gear teeth 520 to disengage from the drive shaft gear teeth 620a. Thus, while the cord 400 is being rewound onto the wheel 200, the drive shaft 600 is not rotated. 
     While the above described action occurs with respect to the wheel 200 and the drive gear 500, the flippers 510a&#39;,b&#39; hold the drive gear 500&#39; disengaged from the gear 610. Accordingly, the drive gear 500&#39; and the cord take-up wheel 200&#39; do not rotate with the drive shaft 600 and the drive shaft gear 610. In addition, the spring 300&#39; helps in holding the cord take-up wheel 200&#39; stationary during this process. 
     When the cord 400&#39; wrapped around the reel portion 201&#39; of the cord take-up wheel 200&#39; is pulled, the teeth 520&#39; of the drive gear 500&#39; engage the teeth 620b of the drive shaft gear 610 in a manner similar to that described above. This causes the drive shaft 600 to turn in the second direction b that is opposite the first direction a. When the cord 400&#39; is released, it is recoiled onto the cord take-up wheel 200&#39;, and the apparatus becomes disengaged in a manner similar to that described above. 
     As described above, the present invention provides a dual action retractable cord take-up reel for adjusting a position of a window covering without a cord loop. 
     Although only preferred embodiments are specifically illustrated and described herein, it will be appreciated that many modifications and variations of the present invention are possible in light of the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention.