Abstract:
A holder for interconnecting a carrier in a control system for a vertical vane covering for architectural openings with a suspended vane includes first and second parts with horizontally oriented engagement portions which are interconnectable at vertically spaced positions to move the parts between a plurality of adjusted vertical positions to adjust the spacing between the suspended vane and its associated carrier.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to European patent application No. 05075059.5, filed 11 Jan. 2005, which is hereby incorporated by reference as if fully disclosed herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to a holder for a vane of a vertical venetian blind assembly used, for instance, for covering an architectural opening, such as a window or door.  
         [0004]     2. Description of the Related Art  
         [0005]     Vertical venetian blinds have generally been provided with horizontally-extending head rails, holding a plurality of carriers or travellers that can be moved in spaced apart relationship along the longitudinal length of each head rail. Each carrier has typically supported a vertically-extending louver, slat or vane by a vane holder in such a manner that the consumer of the venetian blind could move the vane along the length of the head rail (e.g. by pulling on a first operating cord or pull cord) and also could rotate or tilt the vane about its vertical axis (e.g. by pulling on a second operating cord or tilt cord). For this purpose, each carrier has typically included a main body with a vertically oriented drive hub or worm wheel, drivingly connected to a horizontally oriented worm gear. The bottom of each drive hub has supported a depending vane holder, adapted to hold securely the top of a vane while its carrier has been moved longitudinally and while the drive hub has been rotated so as to move the vane holder and the vane and tilt them about their common vertical axis. In this regard, a longitudinally-extending tilt rod or drive shaft has been provided in the head rail, extending through the carriers and engaging their worm gears, whereby rotation of the tilt rod about its longitudinal axis has caused the drive hubs of the carriers to rotate about their vertical axes so as to make the vane holders and the attached vanes tilt together.  
         [0006]     A problem in mounting a vertical venetian blind in a slanted or sloped architectural opening is that, for each slope angle, different vane holders are required. Specifically, a suitable length for the holder has to be chosen for each related slope under which the blind is mounted, since the length of the vane holder influences the space the vane of the blind has for rotating and thus tilting. When the holder is too short, the upper marginal portion of the vane hits the head rail when rotated. When the holder is too long, it negatively affects the look of the blind. The steeper the slope, the longer the holder has to be. Generally, a blind manufacturer will offer a limited number of different length holders, each having a specific length and use for a specific number of slopes. So each holder of a specific length will be used for a range of slope angles. This is not ideal and will lower the quality of a blind product since it will not always be possible to have holders of the specific length necessary for a desired slope. The same problem occurs with curved mountings.  
         [0007]     U.S. Pat. No. 6,000,456 solves a similar problem, based on a difficulty that can be encountered when mounting a vertical blind assembly adjacent an architectural opening. In particular, where the vanes of the vertical blind assembly are of a particular length, it is necessary that the head rail is positioned and mounted accurately relative to the architectural opening. If the head rail is mounted too high or too low, it becomes necessary to remount it, possibly causing undesirable damage to the architectural opening surrounding. As a solution to this problem, U.S. Pat. No. 6,000,456 proposes a vane holder having an adjustable length. The holder has a vane clasp and a clasp holder, the vane clasp having a first end, to which the vane of the blind is attached, and a second end which can be attached to the clasp holder. The holder, in turn, can be attached to a carrier of a vertical blind. The second end of the clasp has ratchet grooves, each of which can cooperate with a single locking tooth in the holder, such that a resilient ratchet-type mechanism is created. The clasp can be moved resiliently between engaging consecutively one of the securing points or ratchet grooves to the locking tooth in the holder so as to vary the height of the vane.  
         [0008]     The adjustable length vane holders of U.S. Pat. No. 6,000,456 could, in theory, be used to solve the problem of sloped vertical blinds. Unfortunately, this is not the case since such holders were designed only for correcting small inconvenient differences in length. Furthermore, the connection between the vane clasp and the clasp holder is a single point connection, which is not a very reliable connection. In order to make the connection of the single locking tooth and the ratchet grooves more secure, the profile or depth of the locking tooth would have to be substantial. However, this would prevent adjustment of the vane holder of U.S. Pat. No. 6,000,456, which is a ratchet mechanism. Moreover, this would still not provide a really secure connection because of its single point of connection.  
       SUMMARY OF THE INVENTION  
       [0009]     In order to provide an adjustable length holder that can support a vane from a carrier of a vertical blind assembly and that is more reliable and provides a more secure connection between the carrier and the vane, the holder of this invention comprises: 
        a length adjustable mounting comprising a first end portion connectable to the carrier and a second end portion connectable to a hook member for suspending the vane and     the length adjustable mounting further comprising a first part extending downwardly in relation to the first end portion and comprising a first engagement portion projecting substantially horizontally and a second part extending upwardly in relation to the second end portion and comprising a second engagement portion projecting substantially horizontally,     the first and second parts being operably engaged by the first and second engagement portions in a manner to allow displacement of the parts upwardly or downwardy relative to each other, by which the second end portion can be moved into a plurality of adjusted vertical positions relative to the first end portion,     characterized in that the first part comprises at least one first arm extending downwardly from the first end portion and a plurality of first engagement portions are on the at least one first arm and the second part comprises at least one second arm extending upwardly from the second end portion and a plurality of second engagement portions are on the at least one second arm and wherein, in any of the adjusted vertical positions, more than one of the plurality of the first engagement portions are opposite, and in operative engagement with, more than one of the plurality of the second engagement portions.        
 
         [0014]     Advantageously, the first and second engagement portions are complementary engagement portions. It is especially advantageous that each of the first and second engagement portions comprises at least one ridge and the ridge projects horizontally of the first or second arm, on which the ridge is positioned. It is particularly advantageous that each ridge is tooth-like. It is quite particularly advantageous that each tooth-like ridge has a cross-sectional shape of a right angled triangle, with a base, a short leg and a long leg and wherein the apex of each ridge is formed by the right angle of the triangle and the base or hypotenuse of each tooth-like ridge extends horizontally of the arm, on which the ridge is positioned. It is also particularly advantageous that each tooth-like ridge is set at an angle or pitch relative to the vertical direction of the arm, wherein each ridge of the first engagement portions is set such that the short leg is downwardly oriented at an acute angle relative to vertical and wherein each ridge of the second engagement portion is at a second pitch angle that is identical but complementary to the angle of the first tooth-like ridge and thus has its short leg upwardly oriented at an acute angle relative to vertical.  
         [0015]     Also advantageously, the first part of the length adjustable mounting comprises two downwardly extending first arms that are opposite and parallel to each other and the second part of the length adjustable mounting comprises two upwardly extending second arms that are opposite and parallel to each other, and the arms of the first and second parts have cross-sectional shapes such that the arms can be fitted together such that when the second part of the length adjustable mounting is moved up or down relative to the first part, the arms of the second part move in the same vertical direction relative to the arms of the first part. It is especially advantageous that the cross-sectional shape of each arm is a pie-point shape, and each arm comprises an outer wall and two radial walls, the radial walls projecting radially inward from the outer wall and shaping the point of pie-point shape.  
         [0016]     Also advantageously, the adjustable mounting further includes a locking member surrounding the first and second arms of the first and second parts of the adjustable mounting and being movable between a locked position in which relative movement between the first part and the second part is prevented and an unlocked position in which relative movement between the first part and the second part is possible. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     Further aspects of the invention will be apparent from the following description and the accompanying drawings in which:  
         [0018]      FIG. 1  is a perspective view of a vertical blind assembly including a vane holder of this invention;  
         [0019]      FIG. 2A  is a perspective view of a first embodiment of the vane holder of the invention, attached to a carrier;  
         [0020]      FIG. 2B  is an exploded perspective view of the vane holder and carrier of  FIG. 2A ;  
         [0021]      FIGS. 3 and 4  are perspective views of the adjustable portions of the vane holder of  FIGS. 2A and 2B ;  
         [0022]      FIG. 5  is a detailed view of the complementary engagement of the adjustable portions of the vane holder of  FIGS. 2A and 2B ;  
         [0023]      FIG. 6  is a detailed view of the complementary engagement of the adjustable portions of a vane holder of a second embodiment of the invention;  
         [0024]      FIG. 7  is an exploded perspective view of the complementary engagement of the adjustable portions of a vane holder of a third embodiment of the invention; and  
         [0025]      FIG. 8  illustrates the configuration of the complementary engagement of the adjustable portions of a vane holder of additional alternative embodiments of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]      FIG. 1  shows a vertical blind assembly  1  which includes a plurality of vertical vanes or louvers  3  suspended from a generally longitudinally-extending head rail  5  that is mounted at an upward slope or angle (from left to right in  FIG. 1 ). The vanes  3  may be conventional metal, plastic or fabric slats, each having an upper marginal portion  7  securely suspended vertically from a holder  15 . Each holder  15  is attached to a conventional carrier or traveller (not shown) that extends downwardly from, is carried by, and can be moved longitudinally along, the head rail  5 .  
         [0027]     As shown in  FIG. 1 , the head rail  5  may also be provided with a conventional pull cord  9  for moving a plurality of the carriers along the head rail and a conventional bead chain  11  which serves as a tilt cord for rotating a grooved tilt rod (not shown) of the head rail  5  so as to tilt the vanes  3 .  
         [0028]      FIGS. 2A and 2B  show the vane holder  15  with a carrier  13 , which can be carried by the head rail  5 . The carrier  13  and holder  15  can be can be attached to each other in any conventional manner, but a two-way mounting, such as a gimbals mounting  31  as described below is preferred for this purpose. The vane holder  15  includes a hook member  17  for carrying the vane  3 . The hook member  17  has two opposing arms  19 ,  21  which, as shown in  FIG. 3 , include a hook portion  23  which mates with a recess  23 A to engage with the top of the vane. Other types of hook members could be used as long as they can hold the vane.  
         [0029]     The vane holder  15  also features a ratchet-type adjustable mounting  25  which allows the vertical length of the holder to be changed between its attachment to the carrier  13  and its hook member  17 . The adjustable mounting  25  includes an upper or first part  27  that is itself attachable to the carrier  13 , and a lower or second part  29  that is attached to the hook member  17 . The first part  27  of the holder  15  is attached to the carrier  13  by means of a conventional gimbals mounting  31  which allows the vanes  3  to remain vertically oriented in any position. The gimbals mounting  31  includes a lower part  33  for connecting to the holder  15 , and specifically to the first part  27  of its adjustable mounting  25 , and an upper part  35  for connection to the carrier  13 . The upper part  35  of the gimbals mounting includes a shaft with wedge-like projections  39  protruding therefrom for cooperation with the tilt gear in the carrier  13 . Thereby, the gimbals mounting allows the pivoting motion of the vane holder  15  for tilting, while at the same time keeping the vanes vertical.  
         [0030]     As most clearly illustrated in  FIGS. 3 and 4 , the second part  29  of the adjustable mounting  25  may be formed integrally with or detachably mounted to the hook member  17  respectively. However, in the illustrated embodiment, the second part  29  of the adjustable mounting  25  is integrally formed with the hook member  17 .  
         [0031]     As further illustrated in  FIGS. 1-5 , the first part  27  of the adjustable mounting  25  includes two parallel opposing first arms  44  and  46  extending downwardly from a first base  48 . The first arms  44  and  46  also extend upwardly past the first base  48  where they are joined by a bridging member  40  to form a hollow attachment member  42  for the lower part  33  of the gimbals mounting  31 . The second part  29  of the adjustable mounting  25  similarly includes two parallel opposing second arms  50  and  52 , extending upwardly from a second base  54 . In the assembled adjustable mounting  25 , the first base  48  is upwards from the second base  54 . The first and second arms  44 ,  46 ,  50  and  52  extend vertically towards each other in the assembled adjustable mounting  25  to allow adjustment of the vertical distance between the first base  48  and second base  54 .  
         [0032]     As illustrated, the first arms  44  and  46  of the first part  27  are arranged in a complementary manner with regard to the second arms  50  and  52  of the second part  29 . In particular, the first part  27  and second part  29  may be fitted together such that, for a cross-section through the adjustable mounting  25 , the arms  44 ,  46 ,  50  and  52  occur alternately around a vertical axis running through the adjustable mounting  25 .  
         [0033]     As illustrated, the first arms  44 ,  46  of the first part  27  and the second arms  50 ,  52  of the second part  29  have a cross-section in the shape of pie-points. Each arm has an outer wall  44 A,  46 A,  50 A,  52 A that is curved and has left and right inner walls  44 B,  44 C,  46 B,  46 C,  50 B,  50 C and  52 B,  52 C which extend horizontally and radially inwardly with respect to the vertical axis of the adjustable mounting  25 . In particular, as illustrated, the left and right radial walls  44 B,  44 C,  46 B,  46 C of the first arms  44 ,  46  of the first part  27  oppose and engage with corresponding left and right radial walls  50 B,  50 C and  52 B,  52 C of the second arms  50  and  52  of the second part  29 . The inner or radial walls of the first arms  44 ,  46  are provided with a substantially horizontally outwardly projecting profile which forms a plurality of first engagement portions  60 . Similarly the inner or radial walls of the second arms  50  and  52  are provided with a substantially horizontally outwardly projecting profile which forms plurality of second engagement portions  61 . The shape of each of the first and second engagement portions  60 ,  61  is best visible in  FIG. 5  and are shaped as a ridges  62 ,  64  that are tooth-like and project substantially horizontally outwardly relative to the wall surface. The tooth-like ridges  62 ,  64  extend along all or at least a siginificant part of the width of the surfaces of the radial walls of the first arms  44 ,  46 .  
         [0034]     Adjacent each tooth-like ridge  62 ,  64  is a groove  63 ,  65 . The ridges and grooves together are shaped to form a ridge-groove profile or a saw-tooth profile. The ridges  62  of the first arms of the upper part  27  are shaped to be complementary to the ridges  64  of the second arms of the lower part  29 . The tooth-like ridges  62 ,  64  can be of any shape, but in order to facilitate easy adjustability of the first and second parts  27 ,  29  relative to each other, they are preferably shaped like a right triangles which are set on the first and second arms at an angle or pitch relative to the vertical axis. The right triangles of the ridges  62 ,  64  each have a base or hypotenuse  62 A,  64 A, a short leg  62 B,  64 B and a long leg  62 C,  64 C. For each triangle, the legs project from the base, and extend towards each other, at an acute angle and join each other at the right angle tooth apex  62 D,  64 D. The base or hypotenuse of each ridge extends vertically and is preferably integral to the respective radial wall, the right angle forming the apex of the tooth-shaped ridges and projecting substantially horizontally outwardly from the radial wall. Alternatively, the tooth apex can be rectangular or curved or rounded. The pitch angle of the first tooth-like ridges  62  on the first arms of the upper part is such that the short leg  62 B is downwardly oriented at an acute angle relative to vertical. The second tooth-like ridges  64  on the second arms of the lower part are identically shaped but placed up-side down relative to the first teeth  62 . So the preferred second pitch angle of the second tooth-like ridges  64  is identical but complementary to the first angle of the first part teeth and and has its short leg ( 64 B,  164 B) upwardly oriented at an acute angle relative to vertical. The preferred pitch angle is about 20-40 degrees, particularly about 30 degrees. The preferred horizontal depth of the tooth-like ridges  62 ,  64  is about 0.3 mm. In this manner, the adjustability of the arms in an upward direction is easier than in a downward direction. This is desirable in order to maintain a reliable and operative connection between the radial walls of the upper and the lower parts  27 , 29  of the adjustable mounting  25  of the vane holder  15 .  
         [0035]     Each of the first part and the second parts of the adjustable mounting  25  includes a plurality of engagement portions  60 ,  61 ,  62 ,  63 ,  64 ,  65 , and at each of the possible adjusted positions, more than one of the complementary respective first and second tooth-like ridges  62 ,  64  are in operative connection with one another. This is best seen in  FIGS. 2A and 5 , where even at the lowest possible adjusted position more than one of the tooth-like ridges are in operative connection.  FIG. 5  clearly shows a plurality of the first and second tooth-like ridges in operative connection. This greatly enhances the reliability of the adjustable mounting  25 .  
         [0036]     With the holder  15 , at least its arms  44  and  46  of its first part  27  are able to flex with respect to the base  48 . The arms  44  and  46  may be made of a material allowing them to flex along their lengths or may be connected to the base  48  so as to allow movement relative to the base  48 . In this way, the arms  44  and  46  behave similar to cantilevers with respect to the base  48 . Similarly the arms  50  and  52  of the second part  29  can be made to be able to flex relative to base  54 .  
         [0037]     With the first arms  44  and  46  of the first part fitted between the second arms  50  and  52  of the second part  29 , the engagement portions, the teeth-like ridges-groove formations  62 - 63 ,  64 - 65  formed on the radial walls  44 B,  44 C,  46 B,  46 C,  50 B,  50 C and  52 B,  52 C provide resistance to relative movement of the first part  27  and second part  29  vertically. The flexing of the first arms  44  and  46  of the first part  27  produces horizontal movement (i.e. radial movement with respect to the vertical axis of the adjustable mounting  25 ) of the tooth-like ridges  62 ,  64  formed on the radial walls, such that the first part  27  and second part  29  can move slidingly relative to one another vertically. This flexing partially or completely disengages the engagement portions of the first and second parts  27 ,  29 . The ability to slidingly move the first and second parts  27 ,  29  of the adjustable mounting  25  adds ease of adjustability to the adjustable mounting.  
         [0038]     This also means that since the first and/or second legs can flex a smaller horizontal distance outwardly nearer their base  48 ,  54 , the ease of adjustability tends to decreases as the adjustable mounting  25  is put into its relative adjusted positions nearing its shortest length.  
         [0039]     A first way of countering this effect is by varying the horizontal extent of the apex of the teeth-like ridges according to their position on the arm. Such that the first or second teeth that are positioned nearer their respective base  48 ,  54  are of a smaller horizontal extent than the first or second teeth that are nearer the free ends of their respective first or second arms. This means that the smaller horizontal flexing distance of the arms near their base is effectively neutralized.  
         [0040]     Another way of countering this effect, is by shaping the apex of the teeth progressively rounder for teeth that are closer to the base  48 ,  54 . This is illustrated in  FIG. 6 .  FIG. 6  thus illustrates a second embodiment of the invention, to avoid repetition of description, like features have references supplemented by  100 . In  FIG. 6  it is clear that the first teeth  162  on the first arm  144  of the first part, that are near the base  148  have a considerably rounder apex than the teeth near the free end of that arm. The same for the teeth  164  on the arm  150  of the second part.  
         [0041]     Thus the combination of the shape and pitch of the teeth-like ridges and the flexibility of the arms determines the degree of the ease of vertical adjustability and the securedness of the connection between the first and second parts  27 ,  29  of the vane holder  15 .  
         [0042]     Where the ease of vertical adjustability and particularly sliding adjustability is deemed very important in the holder  15 , this can be detrimental to the securedness of the connection of the two parts. When this is the case, the holder  15  preferably includes an additional locking member to prevent its two parts from disengaging while retaining the easy sliding adjustability.  
         [0043]      FIGS. 2-4  show the use of such an optional locking member. To better secure the first part  27  relative to the second part  29  and, hence, better hold the adjustable mounting at a particular length, a lock can be provided in the form of a collar  66 . The collar  66  defines a through-hole  68  having dimensions to match the outer surfaces of at least the first arms  44 ,  46  of the first part  27 .  
         [0044]     The collar  66  is able to move vertically with respect to first part  27 . With the collar  66  in the vicinity of the first base  48  of the first part  27 , the first arms  44 ,  46  are able to flex, thereby providing horizontal movement of the engagement portions and allowing relative vertical movement of the first and second parts  27 ,  29 . However, with the collar  66  moved to a vertical end of the first part  27 , distal from the base  48 , the first arms  44 ,  46  are prevented from moving outwardly in a horizontal direction, such that the respective engagement portions of the first part  27  and second part  29  are held in engagement and relative vertical movement of the first and second parts  27 ,  29  is not possible.  
         [0045]      FIG. 2A  illustrates the adjustable mounting  25  in a vertically-extended state with the collar  66  at the vertically distal end of the first part  27 . In this position, the adjustable mounting  25  is held securely in its extended state. Unless a user forces the arrangement to the point of damage or destruction, merely applying a vertical force to the first part and second parts  27 ,  29  will not result in any adjustment of the vertical length of the adjustable mounting  25 .  
         [0046]     To prevent the collar  66  from moving beyond the vertically distal end of the first part  27 , at least one of the first arms  44 ,  46  is provided with a horizontally (i.e., radially) extending flange  70 ,  72  at the vertical end thereof. Preferably, each first arm is provided with such a flange. Hence, the collar is prevented from moving vertically beyond the distal end of the first part  27 , since it abuts the flanges  70 ,  72 . In some situations, there may also be concern that the collar  66  will inadvertently move the first part  27  vertically towards its base  48 . For example, pre-assembled vane holders  15 , prior to attachment to the head rail  5 , are stored and transported as separate parts. During transport, it is possible for the collar  66  to slide out of place and subsequently for the parts to move relative to each other. To prevent this, at least one of the arms  44  and  46  of the first part  27  is provided with a horizontal protrusion  74 ,  76 . These protrusions either provide a tighter fit between the collar  66  and the outside surfaces of the first arms  44 ,  46 , or as shown in  FIGS. 3 and 4 , it can be placed at a position along the arm to create a ring zone  77  between the flanges  70 ,  72  and the protrusion  74 ,  76 . The ring zone  77  preferably has a height equal to the height of the ring  66 . The ring  66  can be forced over the protrusion  74 ,  76  due to a small amount of horizontal flexing of the arms  44 ,  46  and settles in the ring zone  77  at the vertically distal end of the first part  27 . Hence, there is some resistance to the collar  66  moving upwardly beyond its position at the distal end of the first part  27 . In this case, in the relaxed state of the arms, the protrusion  74 ,  76  may define, with the arms  44  and  46 , an area slightly greater than that of the through hole  68  of the collar  66 . The collar can then only be moved vertically beyond the protrusion  68  as a result of the resilience of the arms.  
         [0047]     As shown in  FIG. 4 , each of the arms  44 ,  46  at the vertically distal end of the first part  27  is provided with horizontally, and radially inwardly extending, first stoppers  80 ,  82 . Similarly, but not visible, at the vertically distal end of the second part  29 , distal from its base  54 , each of the second arms  50  and  52  is provided with corresponding inwardly extending second stoppers  84 ,  86 . The first and second stoppers  80 ,  82 ,  84 ,  86  are placed at the meeting point of the radial walls of each arm. When seen in cross-section, the first and second stoppers  80 ,  82 ,  84 ,  86  extend radially inwardly from the point of the pie-point cross-section of each arm.  
         [0048]     In the assembled state, the first stoppers  80 ,  82  of the arms  44 ,  46  of the first part  27  are positioned vertically between the second stoppers  84 ,  86  of the arms  50 ,  52  of the second part  29  and its base  54 . Similarly, the second stoppers  84 ,  86  of the second part  29  are positioned vertically between the first stoppers  80 ,  82  of the first part  27  and its base  48 . The first and second stoppers  80 ,  82  and  84 ,  86  extend horizontally and radially inwardly to a sufficient extent that they interact and meet each other. In this way, when the first part  27  and the second part  29  are moved to the most vertically extended state for the adjustable mounting  25 , the first stoppers  80 ,  82  abut the second stoppers  84 ,  86  so as to prevent the first part  27  from separating from the second part  29 .  
         [0049]      FIG. 4  shows that the first and second stoppers  80 ,  82 ,  84 ,  86  are formed with a ramp profile which extends progressively further horizontally and raadially inwardly at positions closer to the respective bases  48  and  54 . In this way, during assembly of the vane holder  15 , it is possible to push the first and second stoppers  80 ,  82 ,  84 ,  86  past one another. A similar function may be achieved by providing a suitable first stopper on only one of the first arms  44 ,  46  and/or a second stopper on only one of the second arms  50  and  52 . Indeed, where the adjustable mounting  25  is arranged such that the first arms  44 ,  46  flex, but the second arms  50 ,  52  remain rigid, it is possible for the second stoppers to be replaced by a component bridging the vertically distal ends of the parts  50  and  52 .  
         [0050]     By lifting the collar  66  and moving it upwardly to a position in the vicinity of the base  48  of the first part  27 , the first arms  44 ,  46  are able to flex horizontally and radially outwardly such that the engagement portions  60 ,  61  formed on the radial walls  44 B,  44 C,  46 B,  46 C,  50 B,  50 C and  52 B,  52 C are moved horizontally and radially apart and the relative vertical position of the first and second parts  27 ,  29  can be adjusted. For example, the relative vertical positions of the first part  27  and second part  29  can be changed such that the adjustable mounting  25  is at its minimum vertical length. By moving the collar  66  back down to a position at the vertically distal end of the first part  27 , the adjustable mounting again becomes locked. In particular, the arms  44  and  46  of the first part  27  cannot flex horizontally and radially outwardly, and the respective engagement portions  60 ,  61  formed on the walls  44 B,  44 C,  46 B,  46 C,  50 B,  50 C and  52 B,  52 C of the first and second parts  27 ,  29  remain in engagement.  
         [0051]      FIG. 6  shows a second embodiment  115  of the adjustable length holder of the invention which is similar to the holder  15  of  FIGS. 1-5  and for which corresponding reference numerals (greater by  100 ) are used below for describing the same parts or corresponding parts.  
         [0052]     In the holders  15 ,  115  of  FIGS. 1-6 , the first and second engagement portions  60 ,  61 , 160 , 161 , formed on the left and right radial walls of the first and second arms are complementary saw tooth profiles  62 - 63 ,  64 - 65 ,  162 - 163 ,  164 - 165 . This is advantageous in providing engagement over a large surface area and, with only partial disengagement, allowing relative vertical movement of the first part  27 , 127  and second part  29 , 129 . However, if slidable relative vertical movement of the parts is not desired, it is possible to use a stepped or square-wave profile. When such a profile is used, it is necessary that the arms, in a relaxed state, are in line from one another, i.e. completely disengaged.  
         [0053]      FIG. 7  shows a third embodiment  215  of the adjustable length holder of the invention which is similar to the holder  15  of  FIGS. 1-5  and for which corresponding reference numerals (greater by  200 ) are used below for describing the same parts or corresponding parts.  
         [0054]     The adjustable mounting  225  of the holder  215  includes a first part  227 , a second part  229  and a locking member  266 . The first or upper part  227  is connectable to a holder (not shown) and comprises a single first arm  244  extending from a base portion  248 . The arm  244  includes an outer wall  244 A, and an inner wall  244 D and left and right walls  244 B,  244 C. The outer wall  244 A comprises a plurality of first engagement portions  260 . The second or lower part  238  is connected or connectable to a vane hook member  217  at the lower end. It further comprises a base portion  254  and an arm  250  extending vertically away from the base  254 . The arm  250  is a U-shaped profile having a base wall  250 A, and left and right wall  250 B,  250 C extending from the base. The inner surface of base  250 A is provide with a plurality of engagement portions (not shown).  
         [0055]     The engagement portions on the inner walls  244 D and  250 A of the arms  244  and  250  of the two parts  227 , 229  of the adjustable mounting are complementary ridge-groove profiles  262 - 263 ,  264 - 265 . The ridges  262 ,  264  are rectangular horizontally extending ridges. Adjacent each ridge  262 , 264  is a groove  263 , 265 . The grooves are of complementary shape to the ridges, so in this embodiment, the grooves also have a rectangular cross-sectional shape. When the inner walls  244 D and  250 A are brought into contact the complementary ridges-groove profiles provide an operative engagement between the two parts.  
         [0056]     By surrounding the so-engaged arms  244 ,  250  by the locking member  266 , the connection is secure. The locking member  266  is preferably a hollow sleeve like ring member. The hollow interior  268  having a cross-section that is designed to match the outer surfaces of the arms  244 ,  250  in engagement with each other.  
         [0057]     In order to adjust the adjustable mounting  225  to change the vertical length of the holder  215 , the sleeve  266  is removed from the first and second parts  227 ,  229 . This allows horizontal displacement of the arms  244 ,  250  relative to each other. The new length is then chosen, the arms are brought into engagement by moving the arms horizontally together, and the sleeve is slid over the connected arms. The connection is very secure, and the adjustability can be more accurate than with the slidable embodiment.  
         [0058]     In this third embodiment alternatively the engagement portions  260  can be shaped to form a snap-fit connection between the two parts. Or the ridges  262  on the first arm can be made slightly wider than the complementary grooves  265  on the second arm, to enhance the friction between the two assembled parts. In such variations the locking member is not required.  
         [0059]     It will be appreciated that many variations are possible in the embodiments of the holder of the invention.  FIGS. 8A-8E  illustrates some of these variations in horizontal or vertical cross-sectional views through the adjustable mounting.  
         [0060]      FIG. 8A  shows a fourth embodiment  315  where the adjustable mounting  325  comprises six arms in total. In the illustrated embodiment there are three first arms  344 ,  346 ,  347  and three second arms  350 ,  352 ,  353  in complementary arrangement.  
         [0061]      FIG. 8B  shows a fifth embodiment  415  where the adjustable mounting  425  comprises a four first arms or arm-like flanges  444 ,  446 ,  447 ,  447 A projecting radially outward from the first part  427 . Four triangularly shaped arms  450 ,  452 ,  453  and  453 A of the second part  429  are in complementary arrangement with the arm-like flanges  444 ,  446 ,  447 ,  447 A of the first part.  
         [0062]     In  FIG. 8C , the first arm  544  of a sixth embodiment  515  is shaped as sleeve like arm-profile and the second arm  550  is inserted therein. In order to provide flexibility to the arms for slidable adjustment the first arm can be provided with vertically extending slits  544 X, and/or the second arm can be a-two part arm.  
         [0063]     In  FIG. 8D , the first part  627  of a seventh embodiment  615  comprises two opposite spaced apart first arms  644 ,  646 , the second part  629  comprises a single arm  650  that is located between the two first arms.  
         [0064]      FIG. 8E  shows a vertical cross-section of the first and second parts  727 ,  729  of an eighth embodiment  715 . First arm  744  is provided with a square ridge-type profile and the second arm is provided with a complementary type profile.  
         [0065]     This invention is, of course, not limited to the above-described embodiments which may be modified without departing from the scope of the invention or sacrificing all of its advantages. In this regard, the terms in the foregoing description and the following claims, such as “vertical”, “horizontal”, “upward”, “downward”, “upper”, “lower”, “inward”, “outward”, “longitudinal” and “lateral”, have been used only as relative terms to describe the relationships of the various elements of ratchet-type adjustable length vane holder of the invention. For example, when the vane holder is being assembled or when it is sold as a separate part of a vertical venetian blind, it can be in a generally horizontal position, and the holder in such a position would be within the scope of this invention. Also, the collar or locking member  66 ,  266  need not be a closed ring like or sleeve member but could be a C-shaped member that can be clipped about the first arms  44 ,  46 ,  244 ,  246 . The collar could also be a two-part member or a member including a hinge that can be closed about the adjustable mounting  25 ,  225 .