Abstract:
A shaft support for vertical blinds wherein a swing arm automatically extends to span the head rail space in order to support the cords and tilt rod in the head rail as the carrier assembly retracts to open the blind. This swing arm automatically stows away along the head rail when the carrier assembly extends to close the blind so as not to interfere with the motion of the carrier assembly. The automatic operation of this shaft support is such that the mechanism is self correcting in the event that it is installed incorrectly or that it is accidentally moved to an incorrect position during operation.

Description:
This application claims priority from U.S. provisional application No. 60/228,225, filed August 25, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a support arm which automatically swings into position to support the cords and tilt rod in the head rail of a vertical blind as the carrier assembly traverses to open the blind (retracts). As the carrier assembly traverses to close the blind (extends), the support arm automatically swings out of the way so as not to interfere with the motion of the carrier assembly. 
     Typically, a vertical blind transport system will have a top head rail, which both supports the blind and hides the mechanisms that are used to traverse the vanes and the mechanisms that are used to tilt the vanes. The carrier assembly is fully supported along its entire sliding length, as each carrier must be able to support the weight of its corresponding vane. Thus, when the carrier assembly extends, it assists in supporting both the tilt rod and the traverse cords. However, as the vanes traverse open, the tilt rod and the traverse cords remain behind and are thus unsupported except at one end by the head rail and at the other end by the lead carrier which is retreating, leaving an ever-widening unsupported span. The traverse cords, and even the tilt rod, tend to drape down through this unsupported span and stick out past the open bottom of the head rail. This is unsightly and may cause operational problems. 
     The prior art has support arms which, when properly installed, swing across the head rail as the lead carrier retreats, so as to provide a support for the sagging traverse cords and tilt rod. These support arms swing away, back to a stowed position, when the lead carrier is traversing closed and can thus take over the support function otherwise afforded by the support arm. 
     However, if the prior art support arm is in an incorrect position as the carrier assembly is traversing, the support arm will be rendered ineffective. In one instance, if the support arm is in the stowed position as the carrier assembly traverses to the closed position (extends), the lead carrier will impact upon and will not move past the support arm, causing the carrier train to lock up. If the operator uses extreme force to overcome the lock-up, the carrier train will push the support arm to the end of the head rail leaving the support arm inoperative. In the second instance where the support arm is in the “spanning position”(not stowed position) as the carrier assembly traverses to the open position (retracts), the first carrier to come across the support arm will simply drag the support arm with it. The holding force of the support arm is not enough to cause the operator to stop traversing the blind. The support arm is forcibly moved along with the carrier train into an ineffective position, where it remains. 
     SUMMARY OF THE INVENTION 
     The present invention provides a support arm design which has the advantages of prior art support arms, plus it eliminates the problems with prior art support arms which may become inoperative or ineffective if improperly installed or if they are accidentally moved to an improper position during normal operation. 
     In the current invention, as the carrier assembly retracts, the lead carrier activates the support arm, swinging it into the spanning position so as to support the traverse cords and the tilt rod. As the carrier assembly extends, the lead carrier stows the support arm so that it does not interfere with the carrier train. Should the support arm be in the incorrect position, so that it is stowed when it should be spanning, the design of the present invention allows for the support arm and the carrier assembly to “bypass” each other, and yet be ready to properly cooperate with each other to engage the support arm in the right place and at the right time the next time the carrier assembly traverses the blind. 
     The support arm assembly has a ramp, and, in the event that the support arm is already in the stowed position when the carrier assembly is extending (when the support arm should have been in the spanning position instead of the stowed position), the lead carrier guide activating post will move up and over the support arm ramp to bypass the support arm, but will activate the arm when it passes back (retracts) during the next cycle. In the event that the support arm is already in the spanning position when the carrier assembly is retracting (when the support arm should have been in the stowed position instead of the spanning position), the support arm will bring the carrier train to a complete stop. The holding force of the support arm is strong enough to stop the carrier train and to cause the operator to traverse the blind back to the closed position, which will cause the next carrier to reset the support arm to the correct, stowed position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a vertical blind head rail mechanism incorporating a support arm made in accordance with the present invention, shown in the position when the carriers have traversed to the closed position; 
     FIG. 2 is a perspective view, partially broken away, of the vertical blind head rail mechanism of FIG. 1 with a support arm in the spanning position as the carriers have traversed to the open position; 
     FIG. 3 is a partially broken away, exploded perspective view of the support arm and the head rail of FIG. 2; 
     FIG. 4 is the same view as FIG. 3, but with the support arm partially inserted into the head rail; 
     FIG. 5 is the same view as FIG. 4, but showing the support arm finally secured to the head rail; 
     FIG. 6 is a broken away sectional view along line  6 — 6  of FIG. 5, showing the support arm before it has been finally secured to the head rail; 
     FIG. 7 is the same view as FIG. 6, but showing the support arm after it has been finally secured to the head rail; 
     FIG. 8 is a broken away perspective view of the carrier train of FIG. 1 as it traverses open (retracts) and just prior to activating the support arm; 
     FIG. 9 is the same view as FIG. 8, except that the carrier train has retracted far enough to activate the support arm such that the support arm spans the head rail; 
     FIG. 10 is the same view as FIGS. 8 and 9, except that the carrier train has retracted even further, leaving behind the support arm in the activated position, spanning the head rail opening; 
     FIG. 11 is the same view as FIG. 10, as the carrier train starts traversing back to the closed position (extending), showing the support arm in the activated position spanning the head rail; 
     FIG. 12 is the same view as FIG. 11, except that the carrier train has extended to the point where it is just ready to engage the support arm so as to swing it to the stowed position; 
     FIG. 13 is the same view as FIGS. 11 and 12, except that the carrier train has extended even further, leaving behind the support arm in the stowed position, no longer spanning the head rail opening; 
     FIG. 14 is a perspective view of the support arm depicted in all the previous figures, clearly showing the ramp used to allow the lead carrier in the carrier train to “bypass” the support arm when the support arm is incorrectly in the stowed position when it should be in the spanning position; 
     FIG. 15 is a broken away perspective view of the carrier train of FIG. 2 as it extends just prior to encountering the support arm in an incorrect, stowed position when it should be in the spanning position; 
     FIG. 16 is the same view as FIG. 15 but with the lead carrier moving further in the closed position, showing how the lead carrier of the carrier train rides up the ramp of the support arm so as to “bypass” the support arm if the arm is incorrectly in the stowed position when it should be in the spanning position; 
     FIG. 17 is a broken away perspective view of the carrier train of FIG. 1 as it retracts, just prior to encountering the support arm in an incorrect, spanning position when it should be in the stowed position; 
     FIG. 18 is the same view as FIG. 17, showing how a second carrier is about to engage the support arm, which is in an incorrect, spanning position, so as to place it in its correct, stowed position; 
     FIG. 19 is the same view as FIGS. 17 and 18, showing how the second carrier has swung the support arm into its correct, stowed position; 
     FIG. 20 is a broken away perspective view of the head rail of FIG. 5, showing the placement of a screwdriver in order to unlock the support arm from the head rail; 
     FIG. 21 is a sectional view along line  21 — 21  of FIG. 20; 
     FIG. 22 is the same view as FIG. 21, showing the motion required of the support arm in order to unlock it from the head rail; 
     FIG. 23 is the same view as FIGS. 21 and 22, showing the support arm in the now unlocked position, ready to be repositioned or removed; 
     FIG. 24 is a perspective view of the top of the base portion of the support arm mechanism of FIG. 14; 
     FIG. 25 is a perspective view of the bottom of the base of FIG. 24; 
     FIG. 26 is a side view of the base of FIG. 24; 
     FIG. 27 is a perspective view of the top of the swing arm portion of the support arm of FIG. 14; 
     FIG. 28 is a perspective view of the bottom of the swing arm of FIG. 27; 
     FIG. 29 is an exploded end view depicting the initial step in the installation of a second embodiment of a support arm made in accordance with the present invention into a head rail; 
     FIG. 30 is the same view as FIG. 29 but with the support arm properly aligned with and ready to be snapped into the profile of the head rail; 
     FIG. 31 is the same view as FIGS. 29 and 30 but with the support arm finally installed onto the head rail; 
     FIG. 32 is a broken away perspective view of the carrier train for the second embodiment arm of FIG. 29, as it traverses open, just prior to activating the support arm; 
     FIG. 33 is a the same view as FIG. 32, except that the carrier train has traversed open enough to activate the support arm such that the support arm spans the head rail; 
     FIG. 34 is the same view as FIGS. 32 and 33, except that the carrier train has traversed open even further, leaving behind the support arm in the activated position, spanning the head rail opening; 
     FIG. 35 is the same view as FIG. 34, as the carrier train starts traversing back to the closed position, showing the support arm in the activated position spanning the head rail; 
     FIG. 36 is the same view as FIG. 35, except that the carrier train has traversed closed to the point where it is just ready to engage the support arm so as to swing it to the stowed position; 
     FIG. 37 is the same view as FIGS. 35 and 36, except that the carrier train has traversed closed even further, leaving behind the support arm in the stowed position, no longer spanning the head rail opening; 
     FIG. 38 is a perspective view of the support arm of FIG. 37, clearly showing the ramp used to allow the lead carrier in the carrier train to bypass the support arm when the support arm is incorrectly in the stowed position when it should be in the spanning position 
     FIG. 39 is a broken away perspective view of the carrier train of FIG. 35 as it traverses closed just prior to encountering the support arm in an incorrect, stowed position, with the major portion of the swing arm facing away from the oncoming carrier train, when the support arm should be in the spanning position; 
     FIG. 40 is the same view as FIG. 39, showing how the lead carrier of the carrier train rides up the ramp of the support arm so as to bypass the support arm when the arm is incorrectly in the stowed position; 
     FIG. 41 is a broken away perspective view of the carrier train of FIG. 35 as it traverses closed just prior to encountering the support arm in an incorrect, stowed position, with the major portion of the swing arm facing toward the oncoming carrier train, when the support arm should be in the spanning position; 
     FIG. 42 is the same view as FIG. 41, showing how the lead carrier engages, partially swings, and then bypasses the swing arm which was incorrectly stowed as shown in FIG. 41, readying it for final placement in the correct position by the second carrier coming behind the lead carrier; 
     FIG. 43 is a schematic view showing how the lead carrier post of FIG. 42 rides up and over the swing arm so as to bypass it after it has partially engaged it; 
     FIG. 44 is the same view as FIG. 42 but showing how the second carrier is about to engage the swing arm to finish its rotation to the fully and correct stowed position; 
     FIG. 45 is the same view as FIGS. 42 and 44, but showing how the second carrier has swung the support arm into its correct stowed position; 
     FIG. 46 is a side view of the base portion of the support arm of FIG. 38; 
     FIG. 47 is a perspective view of the base of FIG. 46; 
     FIG. 48 is a perspective view of the top of the swing arm portion of the support arm of FIG. 38; 
     FIG. 49 is a perspective view of the bottom of the swing arm of FIG. 38; 
     FIG. 50 is a perspective view of the top of an alternate embodiment of the base portion of a support arm; 
     FIG. 51 is a perspective view of the bottom of the base of FIG. 50; 
     FIG. 52 is a side view of the base of FIG. 50; 
     FIG. 53 is a broken away perspective view of a head rail, showing the placement of a screwdriver in order to unlock the support arm from the head rail when using the alternate embodiment base portion of FIG. 50; 
     FIG. 54 is a sectional view along line  54 — 54  of FIG. 53; 
     FIG. 55 is the same view as FIG. 54, showing the motion required of the screwdriver and the support arm in order to unlock it from the head rail; and, 
     FIG. 56 is the same view as FIGS. 54 and 55, showing the support arm in the now unlocked position, ready to be repositioned or removed. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the blind  10  includes a head rail  12 , and a plurality of vanes (not shown) suspended from the head rail  12  by means of carriers  14  on a carrier train that rides on and is supported by an internal profile  16  (See FIG. 3) of the head rail  12 . A tilt rod  18  runs through, and is supported by, the carrier train. As the tilt rod  18  is rotated, it causes carrier hooks  15  on the carriers  14  to rotate and thus “tilt” the vanes open or closed, as is known in the art. Also running in the head rail  12  space are the traverse cords  20 , which are used to traverse the carrier train open (retracted) and closed (extended). 
     When the vanes are traversed closed (extended), as shown in FIG. 1, the carrier train itself supports both the tilt rod  18  and the traverse cords  20  such that they are held in place within the head rail  12  space and they do not droop below the open bottom of the head rail  12  space to become unsightly and possibly cause operational problems. A support arm  30  may therefore safely be stowed away, parked along the side of the head rail  12 , out of the way of the carrier train. 
     When the vanes are traversed open (retracted), as shown in FIG. 2, the lead carrier  14 A retreats, leaving a progressively longer unsupported gap through which the traverse cords  20 , and even the tilt rod  18  may droop. To avoid this condition, the support arm  30  is swung into its spanning position, by the lead carrier  14 A, across the bottom portion of the head rail  12 . As the lead carrier  14 A retreats further, the support arm  30  remains behind, spanning the head rail  12 , and providing a support for the traverse cords  20  and the tilt rod  18 , to prevent them from drooping below the head rail  12  space. 
     Referring now to FIG. 14, the support arm mechanism  30  includes a mounting base  32  and a swing arm  34 , which pivots relative to the base  32 . FIGS. 24,  25 , and  26  show the mounting base  32  in greater detail. The mounting base  32  is a substantially rectangular piece which is relatively flat on its top surface and which has four appendages projecting from its bottom surface. 
     The first of the appendages  36  is located at a first end  56  of the mounting base  32  and approximately on the longitudinal centerline of the base  32 , and it has a small barb  38  on its unattached end, which is used to lock the mounting base onto the head rail  12  with an interference fit, as will be explained later. This first appendage  36  also serves to locate the mounting base  32  relative to the head rail  12 . 
     The second appendage  42 , like the first appendage  36 , is aligned with the longitudinal centerline of the base  32 . It is located approximately halfway between the first and second ends  56 ,  58  of the base  32  and is mushroom-shaped with a flat cap  44  used to hold the mounting base  32  in the “U” shaped channel profile  46  of the head rail  12  (See FIGS.  3 - 5 ). This appendage  42  also provides a stop for the swing arm  34  when moving to the spanning position, and, as will be explained later, this second appendage  42  is also instrumental in locking the support arm  30  to the head rail  12  when the swing arm is incorrectly in the spanning position and the carrier train is retracting. 
     The third appendage  48  is located approximately halfway between the second appendage  42  and the second end  58  of the base  32 , and it is aligned with the longitudinal centerline of the base  32 . It is a short cylinder with flared out, tapered flanges  49  at its unattached end for the purpose of securing the swing arm  34 , as will be described later. A small ridge  50  with a triangular profile runs perpendicular to the longitudinal centerline of the base  32 , at the attached end of this appendage  48 , the purpose of which is also explained later. This cylindrical appendage  48  is longer than the thickness of the swing arm  34 , but shorter than the distance from the mounting base  32  to the flat cap  44  of the second appendage  42 . 
     A fourth appendage  52  is located at the second end  58  of the base  32  and is also aligned with the longitudinal centerline of the base  32 . Like the second appendage  42 , it is mushroom-shaped with a flat cap  54 , which fits in the “U” shaped channel profile  46  of the head rail  12  (See FIGS.  3 - 5 ). This appendage  52  also provides a stop for the swing arm  34  when moving to the stowed position. 
     FIGS. 27 and 28 show the swing arm portion  34  of the support arm mechanism  30 . The swing arm  34  is L-shaped, including a major, long arm portion  60 , which actually spans across the head rail  12  and a lateral projection or short arm  61  extending perpendicular to the major long arm portion  60  at one end. There is a pivot point hole  62  at the intersection of the two arms  60 ,  61  of the “L”.This pivot point hole  62  has an inside diameter just slightly larger than the outside diameter of the third appendage  48  of the mounting base  32 , such that this third appendage  48  snaps into the hole  62  of the swing arm  34 , allowing the swing arm  34  to swing from the stowed to the spanning position and back. The tapered flanges  49  on the third appendage  48  get squeezed together as the pivot point hole  62  passes over them, and then snap back out effectively pivotally securing the swing arm  34  in place. There are four shallow depressions  64  on the upper surface of the swing arm  34  extending from the pivot point hole  62 , and running parallel to both legs  60 ,  61  of the “L” shaped swing arm  34 . These shallow depressions  64  have a triangular profile, which matches the triangular profile of the ridges  50  found at the attached end of the third appendage  48 . Thus, when the swing arm  34  pivots around this third appendage  48 , there are two positions, corresponding to the fully stowed and the fully spanning positions of the swing arm  34 , when the ridges  50  mate with the shallow depressions  64  to secure the swing arm  34  in place. An extra measure of force is required to break loose the swing arm  34  from the secured position, and the swing arm  34  will tend to remain in one of these two secured positions, thus helping to ensure that the swing arm  34  is either fully stowed or fully spanning across the head rail  12 . 
     At the inner corner of the intersection of the two legs  60 ,  61  of the “L” shaped swing arm  34  there are a recess  66  and a tip  68 . At the end of the lateral projection or short leg  61  of the “L” shaped swing arm  34 , and running parallel to the major portion of long leg  60  on the top surface of the swing arm  34 , there is a ramp  70 , which has a minimum thickness at the outer edge of the short leg and a maximum thickness at the inner edge where it meets the recess  66  and the tip  68 . 
     The swing arm  34  is mounted onto the mounting base  32  by snapping the pivot point hole  62  over the flared out flanges  49  of the third appendage  48 , so that the upper face of the swing arm  34  (with the depressions  64 ) is in contact with the lower face of the mounting base  32  (with the ridges  50 ). As the swing arm  34  bottoms out on the third appendage  48 , the flared out flanges  49  spring back out just enough to secure the swing arm  34  onto the third appendage  48 , while still allowing the swing arm  34  to swing around its pivot point hole  62  from a stowed to a spanning position and back again. While in the fully stowed position (as in FIG.  14 ), the major, long leg  60  of the swing arm  34  abuts the stem of the fourth appendage  52  which thus acts as a stop, and one set of depressions  64  on the swing arm  34  mates with the ridges  50  on the mounting base  32 , thus securing the swing arm  34  in that fully stowed position, preventing the swing arm from accidentally drifting from that fully stowed position. Likewise, while in the fully spanning position (as shown in FIG.  10 ), the tip  68  of the swing arm  34  abuts the stem of the second appendage  42  which thus acts as a stop, and one set of depressions  64  on the swing arm  34  mates with the ridges  50  on the mounting base  32 , thus securing the swing arm  34  in that fully spanning position, preventing the swing arm from accidentally drifting from that fully spanning position. 
     FIGS. 3-7 show how the support arm  30  is mounted onto the head rail  12  of a vertical blind. Once the swing arm  34  and the mounting base  32  have been assembled together, the swing arm assembly  30  is mounted onto the “U” shaped profile  46  of the head rail  12  (See FIGS. 3,  4 , and  5 ) by sliding the stems of the aligned appendages  42 , and  52  between the “legs” of the “U” shaped profile  46 . The support arm  30  is pushed or slid along the channel or recess  46  until it reaches the desired location (See FIG.  5 ), and then pressure is exerted against the first appendage  36  of the base  32  so as to pinch this appendage  36  against the channel  46  (See FIGS.  6  and  7 ). This pinching action forces the barb  38  at the end of the first appendage  36  of the base  32  to snap into the channel profile  46  with an interference fit, thus locking the support arm  30  in place. 
     If the support arm  30  needs to be removed or repositioned (See FIGS.  20 - 23 ), a tool  72 , such as screwdriver blade, is pressed against the side of the mounting base  32  so as to push the mounting base  32  against the head rail  12 . This motion moves the first appendage  36  of the base  32  just far enough to the side to free the barb  38  from the channel  46 . As the barb pops free, the first appendage  36  springs out of the channel  46 , and the mounting base  32  of the support arm  30  slides readily along the channel  46  either to be completely removed from the head rail  12  or to be repositioned along the head rail  12 . 
     FIGS. 8,  9 , and  10  show the operation of the support arm  30  as the carrier train opens the blind (retracts) and the support arm  30  has been installed properly. In FIG. 8, the support arm  30  is in the fully stowed position with the major portion of the support arm  30  parallel to the path of travel of the carriers, as the lead carrier  14 A is about to engage the support arm  30  to move it to the spanning position. Unlike the other carriers  14 , the lead carrier  14 A has two engaging posts  74  projecting downwardly. The engaging post  74  adjacent to the side of the head rail  12  on which the support arm  30  is mounted is positioned so it just slides past the side of the support arm  30 , except at the ramp  70  and tip  68  of lateral projection, which lie in the direct path of that engaging post  74 . When that engaging post  74  reaches the tip  68  of the swing arm&#39;s lateral projection, the post  74  makes contact with the tip  68  and pushes against it, as shown in FIG.  8 . As the lead carrier  14 A continues its travel, the engaging post  74  pushes hard enough against the tip  68  to cause the swing arm  34  to rotate 90 degrees (See FIG.  9 ). In this new position, the swing arm  34  is spanning across the head rail  12 , and the tip  68  has moved so that the engaging post  74  (and therefore also the lead carrier  14 A together with the rest of the carrier train) may continue on its travel to retract the vanes of the blind (See FIG.  10 ). At this point, the tip  68  of the swing arm  34  abuts the stem of the second appendage  42  which thus acts as a stop, and one set of depressions  64  on the swing arm  34  mates with the ridges  50  on the mounting base  32 , thus securing the swing arm  34  in that fully spanning position, preventing the swing arm  34  from accidentally drifting from that fully spanning position. In the spanning position, the swing arm  34  is supported at both ends by the head rail channels  46  and helps support the traverse cords  20  and the tilt rod  18  so they will not droop down below the head rail  12  space. 
     FIGS. 11,  12 , and  13  show the operation of the support arm  30  as the carrier train moves in the direction to close the blind (extended), when the support arm  30  has been installed properly. In FIG. 11, the support arm mechanism  30  is in the fully spanning position as the lead carrier  14 A is moving to the right to close the vanes of the blind. In FIG. 12, the lead carrier  14 A is about to engage the swing arm  34  to move it to the fully stowed position. The engaging post  74  just misses the tip  68  and instead slides into the recess  66  of the swing arm  34 . As the lead carrier  14 A continues its travel, the engaging post  74  pushes hard enough against the swing arm  34  to cause the swing arm  34  to rotate 90 degrees (See FIG.  13 ), back to its stowed position. In this new position, the swing arm  34  is fully stowed along the side of the head rail  12 , and the recess  66  has moved so that the engaging post  74  (and therefore also the lead carrier  14 A together with the rest of the carrier train) may continue on its travel to open the vanes of the blind. 
     FIGS. 15 and 16 show the operation of the blind as the carrier train moves to the closed position (extends) and the swing arm  34  is in an incorrect position, being stowed when it should be spanning the head rail  12 . In FIG. 15, the swing arm  34  is in the fully stowed position (when it should be spanning) as the lead carrier  14 A is moving to close the vanes of the blind. FIG. 16 shows how the engaging post  74  of the lead carrier  14 A rides up the ramp  70  of the lateral projection  61  of the swing arm  34  and passes over the lateral projection or short leg  61 . The lead carrier  14 A thus bypasses the swing arm  34 , leaving it in the correct position for the next cycle when the carrier train opens the blind. 
     FIGS. 17,  18 , and  19  show the operation of the blind as the carrier train opens the blind (retracts) and the swing arm  34  is in an incorrect position, spanning across the head rail  12  when it should be fully stowed. In FIG. 17, the swing arm  34  is in the spanning position (when it should be fully stowed) as the lead carrier  14 A is moving to open the vanes of the blind. The mounting base  32  of the support arm  30  is securely anchored to the head rail  12 , as explained earlier, and the swing arm  34  is securely pivotably mounted to the mounting base  32 . The swing arm  34  cannot pivot in the direction in which the lead carrier  14 A is moving, because the lateral projection or short leg  61  and the tip  68  abut the stem of the second appendage  42  from the base  32 . Therefore, when the carrier hook  15  of the lead carrier  14 A hits against the improperly positioned swing arm  34  of the support arm mechanism  30 , the lead carrier  14 A and the entire carrier train will come to a standstill. Any further pulling by the operator to force the carrier train to traverse will cause the carrier hook  15  to push harder against the swing arm  34 . This in turn causes the tip  68  of the swing arm  34  to push harder against the second appendage  42 , which causes the second appendage  42  to bind in the track opening  46  and wedge itself to prevent sliding motion of the support arm  30  along the track opening  46 . 
     In order to free the carrier train, the operator will reverse the direction of the carrier train, moving the blind back toward a closed position (See FIG.  18 ). When this happens, the carrier hook  15  of the next carrier  14  hits against the swing arm  34  but moving in the opposite direction (since the carrier train is now traveling to close the vanes of the blind), and the swing arm  34  swings to the fully stowed position (See FIG.  19 ), leaving it in the correct position for the next cycle when the carrier train moves to close the blind. 
     Alternate Embodiment of the Support Arm: 
     FIGS. 29-49 show an alternate embodiment of a vertical blind which includes an alternate support arm mechanism  130 . As in the previous embodiment, this support arm mechanism  130  (See FIG. 38) has a mounting base  132  and a swing arm  134  which is mounted to and pivots about the mounting base  132 . Even though the operating concept of this support arm mechanism  130  is very similar to that already described for the support arm  30 , there are some differences which are described below. 
     FIGS. 46 and 47 show the mounting base  132  of the support arm  130 . This mounting base  132  has a trapezoidal-shaped recess  136  with two barbed ends  138 , which are used to mount the base  132  to the head rail  112  as will be explained later. Directly above the recess  136  is a cylindrically-shaped upwardly projecting appendage  140  with flared flanges  142 , used for mounting the swing arm  134  onto the mounting base  132  in the same manner as was described for the first embodiment. A flexible, hooked arm  144  projects from one side of the base  132  and is used to further secure the swing arm  134  onto the mounting base  132  and to provide stops for the swing arm  134  in the fully stowed and the spanning positions, as will be described later. The hooked arm  144  has a small rib  146 , the purpose of which will also be described later. 
     The swing arm  134  (See FIGS. 48 and 49) is a straight arm with a pointed end  148  and a rounded end  150  which forms a semi-circle. At the center of the rounded end  150  is a pivot point hole  162  with a diameter slightly larger than the outside diameter of the appendage  140  of the mounting base  132  and slightly smaller than the diameter of the flanged end  142  of the appendage  140 . The semicircular edge of the end  150  terminates in laterally projecting tips  164  which define recesses  166 . Just in front of these recesses  166  are laterally-extending wedge-shaped ramp projections  170  with a maximum height at the end closest to the recesses  166 , and minimum height at the end furthest from the recesses  166 , the purpose of which will be explained later. The semi-circular edge of the end  150  also has a small indentation  168  half-way between the two projecting tips  164 , as well as indentations  169  just before each of the projecting tips  164 . Finally, the top of the semi-circular edge of the end  150  ramps up from a minimum thickness at the outermost edge to a maximum thickness to form a wedge-shaped ramp edge  172 , best seen in FIG.  38 . 
     The swing arm  134  is assembled to the mounting base  132  (as shown in FIG. 38) by snapping the appendage  140  of the base  132  through the pivot point hole  162  of the swing arm  134 , until the swing arm  134  bottoms out on the base  132  and the flared out flanges  142  snap back out to lock the swing arm  134  in place while still allowing the swing arm  134  to pivot from a fully stowed to a fully spanning position. The flexible, hooked arm  144  snaps over the semi-circular end  150  of the swing arm  134 . The radius of the semi-circular end  150  is such that the rib  146  on the hooked arm  144  interferes slightly with the circumference of the semi-circular end  150  except when the rib  146  is aligned with the indentation  168  on the semi-circular end  150  (corresponding to the spanning position of the swing arm  134  as shown in FIG. 34 ), or when the rib  146  is aligned with one of the two indentations  169  proximate one of the projecting tips  164  (corresponding to a fully stowed position of the swing arm  134  as shown in FIG.  38 ). When the swing arm  134  is in one of these three positions, the rib  146  mates with one of the indentations  168 , 169  thus acting to secure the swing arm  134  in that position. 
     FIGS. 29-31 show the mounting of the support arm  130  onto a head rail  112  which has two brackets  112 A on which the carrier train (not shown) rides. A projecting rail  112 B is utilized for mounting and locking the support arm  130  on the head rail  112 . The support arm  130  is brought into the head rail  112  space as shown in FIG.  29 . The support arm  130  is aligned with the head rail  112  such that the trapezoidal-shaped recess  136  on the mounting base  132  is directly above the projecting rail  112 B of the head rail  112 . The support arm  130  is then pushed down until the mounting base  132  snaps into the projecting rail  112 B, where the barbed ends  138  grip and lock the support arm  130  into place on the head rail  112 . When the swing arm  134  is in the spanning position, the free end of the swing arm  134  rests on the projecting rail  112 C of the head rail  112 . 
     FIGS. 32,  33 , and  34  show the operation of the support arm  130  as the carrier train moves to open the blind and the swing arm  134  is in the proper position. In FIG. 32, the swing arm  134  is in the fully stowed position as the lead carrier  114 A is about to engage the swing arm  134  to move it to the spanning position. Unlike the other carriers  114 , the lead carrier  114 A has two downwardly projecting engaging posts  174 . One of these engaging posts  174  is positioned so it just slides past the side of the swing arm  134 , except that the tip  164  of the swing arm  134  is in the direct path of that engaging post  174 . When that engaging post  174  reaches the tip  164  of the swing arm  134 , the post  174  makes contact with the tip  164  and pushes against it. As the lead carrier  114 A continues its travel, the engaging post  174  pushes hard enough to cause the swing arm  134  to rotate 90 degrees (See FIG.  33 ). In this new position, the swing arm  134  is spanning across the head rail  112  and the tip  164  has moved so that the engaging post  174  (and therefore also the lead carrier  1   14 A together with the rest of the carrier train) may continue on its travel to draw the vanes of the blind (See FIG.  34 ). The rear indentation  168  on the edge of the semi-circular end  150  of the swing arm  134  mates with the rib  146  of the hooked arm  144  of the mounting base  132 , thus securing the swing arm  134  in that fully spanning position, preventing the swing arm  134  from accidentally drifting from that fully spanning position. In the spanning position, the swing arm  134  remains in position and helps support the traverse cords  20  and the tilt rod  18  so they will not droop down below the head rail  112  space. 
     FIGS. 35,  36 , and  37  show the operation of the support arm  130  as the carrier train moves to close the blind and the swing arm  134  is in its proper spanning position. In FIG. 35, the swing arm  134  is in the fully spanning position, as the lead carrier  114 A is moving to close the vanes of the blind. In FIG. 36, the lead carrier  114 A is about to engage the support arm  130  to move it to the fully stowed position. The nearest engaging post  174  will just miss the tip  164  and will instead slide into the recess  166  of the swing arm  134 . As the lead carrier  114 A continues its travel, the engaging post  174  pushes hard enough to cause the swing arm  134  to rotate 90 degrees (See FIG.  37 ). In this new position, the swing arm  134  is fully stowed along the side of the head rail  112 , and the side recess  166  engages the rib  146 . The engaging post  174  (and therefore also the lead carrier  11   4 A together with the rest of the carrier train) may now continue on its travel to close the vanes of the blind. 
     FIGS. 39 and 40 show the operation of the support arm  130  as the carrier train moves to close the blind and the swing arm  134  is in an incorrect position, being stowed (with the swing arm  134  pointing in the direction of travel of the lead carrier  114 A) when it should be spanning the head rail  112 . In FIG. 39, the swing arm  134  is in the fully stowed position (when it should be spanning) as the lead carrier  114 A is moving to close the vanes of the blind. FIG. 40 shows how the engaging post  174  of the lead carrier  114 A rides up the ramp  172  of the swing arm  134 , so that, in fact, the engaging post  174  rides past the projecting tip  164  of the swing arm  134 . The lead carrier  114 A thus bypasses the support arm  130 , leaving it in the correct position for the next cycle when the carrier train moves to open the blind. 
     FIGS. 41 through 45 show the operation of the support arm  130  as the carrier train moves to close the blind and the swing arm  134  is in an incorrect position, being stowed (with the swing arm  134  pointing in the direction opposite the direction of travel of the lead carrier  114 A) when it should be spanning the head rail  112 . 
     In FIG. 41, the carrier train is traversing closed and is about to encounter the incorrectly stowed arm support  130 . In FIG. 42, the lead carrier  114 A has made contact with the support arm  130 . The engaging post  174  of the lead carrier  114 A slides up the ramp  170  (See FIG. 48) on the swing arm and begins to swing the swing arm  134  across the head rail  112  space. However, the swing arm  134  will only swing through a  45  degree angle before the leading edge of the swing arm  134  hits the rear of the lead carrier hook (See FIG. 42) at the point labeled “D”.The engaging post  174  then rides up and over the swing arm  134  in a step-wise manner, as illustrated in FIG. 43, using the rise in height gained from riding up the ramp  70  to overcome the second height of the projecting arm  164 . 
     FIG. 44 illustrates how the swing arm  134  remains at a  45  degree angle, partially spanning the head rail after the lead carrier  11   4 A has passed the support arm  130 . The next carrier  114  then engages the swing arm  134  and finishes pivoting it for a full, combined rotation of 180 degrees (approximately 45 degrees caused by the lead carrier  114 A, and the balance caused by the next carrier  114 ), until the support arm  130  is once again in the fully stowed position, but this time facing in the correct direction so it may be engaged to the spanning position the next time the carrier train traverses open. 
     Finally, the situation may arise where the swing arm  134  is in the spanning position when it should be in the fully stowed position. In this instance, regardless of the direction of travel of the carrier train, the first carrier  114 ,  114 A to come in contact with the swing arm  134  pushes the swing arm  134  to a fully stowed position either into the correct orientation (with the swing arm  134  pointing in the direction of the carrier train in the closed position) or into an incorrect orientation (with the swing arm  134  pointing in the direction of the carrier train in the open position). In the first instance, the swing arm  134  is correctly oriented for when the carrier train traverses to open the blind. In the second instance, the swing arm  134  is incorrectly oriented but will be correctly reoriented via the mechanism described in the previous three paragraphs above (and illustrated in FIGS.  41 - 45 ). 
     FIGS. 50-52 depict an alternate embodiment of a mounting base  32 B which may be used instead of the mounting base  32  of the support arm  30  of FIG.  14 . This alternate mounting base  32 B is identical to the mounting base  32  already described, except it has one more appendage  40 B, and the barb  38 B on the first appendage  36 B is on the opposite side as compared to the barb  38  on the first appendage  36  of the mounting base  32 . Since these bases  32 ,  32 B are practically identical, we will keep the same number designations for both, except that the number designations for the alternate base  32 B will all be followed by the letter “B” to differentiate them from the mounting base  32  already described. 
     The extra appendage  40 B is the only appendage which is not aligned with the other appendages. Instead, it sits to one side of the mounting base  32 B and just slightly forward of the first appendage  36 B, and its purpose, as will be explained in more detail later, is to provide a surface against which to pry a tool, such as a screwdriver, in order to release the lock provided by the barb  38 B of the first appendage  36 B, in the event that it becomes desirable to relocate or remove the support arm  30 B from the head rail  12 . This extra appendage  40 B and its function in releasing the support arm  30 B from the head rail  12 , and the location of the barb  38 B on the first appendage  36 B are the only differences between this alternate embodiment of the support arm  30 B and the previously described support arm  30 . The assembly, installation, and operation remain identical; the only difference is in the removal or relocation of the support arm  30 B as is described below. 
     If the support arm  30 B needs to be removed or repositioned (See FIGS.  53 - 56 ), a tool  72 , such as screwdriver blade, is inserted between the channel  46  and the extra appendage  40 B of the mounting base  32 B. The tool  72  is used to pry the mounting base  32 B away from the channel  46  just enough to allow the barb  38 B of the first appendage  36 B to slide out from the channel  46  and thus disengage the locking mechanism. The support arm  30 B is now free to slide along the channel  46  either to be completely removed from the head rail  12  or to be repositioned along the head rail  12 . 
     It will be obvious to those skilled in the art that modifications may be made to the embodiments described above without departing from the scope of the present invention.