GB2120307A - Blind mechanism - Google Patents

Abstract

The vanes V of a vertical Venetian blind mechanism are each mounted on an auxiliary carrier AC for turning about an upright axis under the control of a sprocket 45, turning about a horizontal axis and connected to the vanes by right angle gearing. Each sprocket is turned by a flexible operating chain OC having parallel portions held in engagement with each sprocket by guides on the carrier. The chain runs within a telescopically sectioned header rod H having a slot S, the edges of which form a track for the carriers. Traversing is effected by a traverse cord TC passing around a pulley at one end of the header H and fastened to a lead carrier LC which carries a return guide defined by walls 87f, 81a for a loop OCL of the chain OC. When the blind is closed by means of the cord TC there is no relative movement of the two portions of the chain and hence no turning of the vanes, but the lengths of chain limit the maximum separation between adjacent carriers. <IMAGE>

Description

SPECIFICATION Blind mechanism This invention relates to blind mechanisms in which vertical vanes are mounted for traversing movement on a header across a window opening between an open and a closed position, and also for angular rotation about an upright axis for light control. In some prior such blind mechanisms, for example as disclosed in U.S. patents 2,755,854; 4,006,769 and 4,257,470, the vertical vanes are mounted on rotary vane supports for traversing movement along the horizontal header and the vane supports are directly connected to a pair of flexible cords or bead chains at fixed locations therealong so that the cords or bead chains control the spacing between adjacent vane supports when the vanes are drawn along the header to a closed position. The cords or bead chains are also manipulatable to control rotation of the vane supports.In these prior blind mechanisms, the cords or bead chains were connected to the vane supports at locations outside the header and the exposed cords or chains not only adversely affected the appearance of the blind mechanism when it was drawn to a closed position, but also drooped or sagged between the vanes when the blind mechanism was drawn to an open position. Further, direct connection of the cord or bead chain to the vanes also limited the maximum possible angular rotation of the vanes so that it was difficult to rotate the vanes through a full 1800 as is desirable for complete light control by the vanes.

Prior vertical blind mechanisms have utilised a header having a slot along the bottom of the header with the vane supports mounted in the slot for movement along the header. However, when the slot is at the bottom of the header, the slot and some of the blind operating mechanism as well as the undecorated interior of the header is exposed to view from the room side of the blind mechanism. In addition, the operating cords for the traverse mechanism sometime droop into and through the downwardly opening slot in the header.

A vertical blind mechanism in accordance with the invention comprises a horizontal rod having a lengthwise extending slot and a track along the slot, a number of auxiliary carriers mounted on the track for movement along the rod and extending through the slot, each auxiliary carrier including a vane support for turning about an upright axis and a sprocket mounted for axial rotation inside the rod and connected to the associated vane support by way of drive means for turning the latter, a flexible operating chain having first and second parallel portions extending inside and lengthwise of the rod, each auxiliary carrier having chain guide means for respectively retaining the two chain portions in meshing engagement with opposite sides of the associated sprocket, traverse means associated with one end of the chain portions operable to move the one end of the chain portion along the rod to an extended position in which the chain portions limit maximum separation between adjacent auxiliary carriers and means associated with the other end of the chain portions for moving the chain portions lengthwise in opposite directions for rotating the sprockets to turn the vanes.

In such a mechanism the vanes are mounted on vane carriers for traversing movement along a header and also for rotary movement about an upright axis for light control and the spacing of at least one vane carrier relative to an adjacent vane carrier can be readily adjusted after the vane carriers and operating mechanism are assembled on the header.

An example of blind mechanism in accordance with the invention will now be described in more detail, with reference to the accompanying drawings, in which:~ Figure 1 is a fragmentary exploded perspective view of the mechanism which is arranged for lefthand operation (as viewed from the front of the rod); Figure 2 is a horizontal sectional view through the mechanism, with traverse and operating cords arranged for right-hand operation (as viewed from the front of the rod); Figure 3 is a rear elevational view of the mechanism of Figure 2; Figure 4 is a longitudinal sectional view taken on the plane 4-4 of Figure 2; Figure 5 is a fragmentary longitudinal sectional view taken on the plane 5-5 of Figure 2 and showing parts of a lead carrier in a moved position and on a larger scale than Figure 2;; Figure 6 is a fragmentary longitudinal sectional view taken on the plane 6-6 of Figure 2 and illustrating parts of the lead carrier in still another moved position and on a larger scale than Figure 2; Figure 7 is a transverse sectional view taken on the plane 7-7 of Figure 2; Figure 8 is a transverse sectional view taken on the plane 8-8 of Figure 2 and illustrating the parts on a larger scale than Figure 2; Figure 9 is a fragmentary horizontal sectional view taken on the plane 9-9 of Figure 8; Figure 10 is an exploded perspective view of a vane carrier; Figure 1 1 is a transverse sectional view taken on the plane 1 1-11 of Figure 2 and showing the parts on a larger scale than Figure 2; and Figure 12 is a fragmentary vertical sectional view taken on the plane 12-12 of Figure 2 and illustrating parts in a moved position and on a larger scale than Figure 2.

The vertical blind mechanism illustrated includes a header rod H adapted to be mounted as by brackets (not shown) on a support surface to extend horizontally across a window opening and rod end caps C1 and C2 at opposite ends of the header rod. A plurality of auxiliary carriers are mounted on the rod for traversing movement therealong and a vane support VS is mounted on each auxiliary carrier for turning movement about an upright axis to rotate a vane Vsupported by each vane support. A lead carrier LC is also mounted on the rod for traversing movement therealong and is extended and retracted by means of a traverse cord TC that extends lengthwise of the rod.A flexible operating chain OC is operatively connected to the lead carrier LC and has first and second chain portions OC, and OC, extending lengthwise of the rod and engaging vane drive sprockets on each of the auxiliary carriers to control spacing between the auxiliary carriers when the lead carriage is extended to close the blind, and to control rotation of the vane supports when the first and second chain sections are moved relative to each other. The traverse cord TC and operating chain OC are operated from adjacent one end of the rod and a latch mechanism LM is provided for releasably latching the lead carrier to the other end of the rod to releasably hold the blind in its closed position.

It is sometimes desirable to be able to adjust the length of the header rod at the time of installation to accommodate windows of different widths and, for this purpose the rod H is advantageously formed in inner and outer telescopically adjustable rod sections H1 and H2.

In the preferred embodiment illustrated, the trackway is formed at the rear side of the rod so as to be concealed from view at the front and bottom of the rod. The inner and outer rod sections H1 and H2 have a like configuration except that the inner rod section has a slightly smaller cross-section than the outer rod section to be telescopically receivable therein, and like numerals are used to designate corresponding parts of the inner and outer rod sections. More specifically, the outer and inner rods sections each include a top wall 21, a front wall 22, a bottom wall 23, and upper and lower rear wall portions 24 and 25 that are spaced apart to define a slot S. The auxiliary carriers each include a slide body 31 that extends through the slot S in the rod sections.The slide bodies are formed of a resilient wear resistant material and may, for example, be formed of synthetic resin such as acetal resin. As best shown in Fig. 8, each slide body has an upper groove with laterally spaced inner and outer upper guide walls 32a, 32b and a lower groove with laterally spaced inner and outer lower guide walls 33a and 33b arranged to guide the auxiliary carrier along the upper and lower rear rod wall portions 24 and 25.

A vane support VS is rotatably supported on each of the slide bodies 31 rearwardly of the header rod for rotation about an upright axis and has a shaft portion 38a and a lower vane engaging portion 38b. The vane supports VS are of a synthetic resin material which is preferably transparent and may, for example, be formed of a transparent polycarbonate resin. In order to facilitate assembly and also disassembly for replacement of the vane supports, the slide bodies 31 are formed with a semi-cylindrical sleeve portion 31a that extends through slightly greater than 1 800 and adapted to rotatably receive the generally upright shaft portion 38a of a vane support with a snap fit.

A drive shaft 41 is mounted in a bore 31 b in each slide body for rotation about a generally horizontal axis transverse to the rear wall of the rod and a right angle gear drive connects the outer end portion of the drive shaft to the vane support. The drive shaft is conveniently formed of a synthetic resin material which may, for example be an acetal resin. As best shown in Figs. 8 and 9, the right angle drive shaft includes a worm gear 42 formed integrally with the outer end of the drive shaft 41 and which meshes with a worm wheel 43 conveniently formed integrally with the upper end of the shaft 38a on the vane support.

The gear drive is advantageously arranged to effect a speed reduction between shaft 41 and vane support VS to enable more accurate control of the angular position of the vane support and to also reduce the tension on the operating chain OC required to rotate the vane supports on all of the auxiliary carriers. For example, the worm and worm wheel drive shown provides about an eight to one speed reduction, so that four revolutions of the shaft 41 turn the vane support through 1800.

A sprocket 45 is provided on the inner end of the drive shaft on each auxiliary carrier for rotating the drive shaft and chain retainer guides 31 c and 31 are provided on the slide body to guidably retain the first and second runs OC, and OC, of the operating chain in meshing engagement with the associated sprocket at diametrically opposite sides of the sprocket. The sprocket has a flange 45b at one side and the chain retainer guides 31 c and 31 d have a portion extending along the side of the sprocket opposite the flange 45b and a portion spaced outwardly from the periphery of the sprocket at diametrically opposite sides thereof for retaining the bead chain in meshing engagement with the sprocket.A slip clutch is advantageously provided in the drive between the sprocket and the vane support to prevent damage to parts in the event one or more of the vanes engages an obstruction during rotation and to also enable synchronization of the vanes on the several auxiliary carriers.

The slip clutch is provided between the sprocket 45 and the drive shaft 41 and, as best shown in Fig. 10, the sprocket is provided with a non-circular opening 45c, conveniently square in cross-section, and the drive shaft 41 is provided with a radially compressible portion 416 that extends into the hole 45c in the sprocket and which has a protrusion 41 c engageable with the non-circular opening 45c in the sprocket. The shaft 41 is formed of a resilient plastic material and the radially compressible portion 41 b is provided by a diametrical slot 41 din the shaft.

The protuberance 41 c is provided on the outer periphery of the shaft at a location intermediate the ends of the slot and normally extends into a corner of the non-circular opening 41 c so that the shaft normally rotates with the sprocket, but can yield in the event rotation of the shaft is restricted.

Locating lugs 41 e and 41 are also provided on the outer periphery shaft in the diametrically compressible portion of the shaft and, as best shown in Fig. 8, one end of each of the lugs is beveled or inclined to facilitate insertion of the shaft through the bore 31 b in the slide and through the opening 45c in the sprocket. The lug 41tis provided at a location on the shaft to engage the inner side of the slide body 31 to inhibit axial withdrawal of the shaft, and the lug 4axis provided at a location to engage the inner side of the sprocket to axially retain the sprocket on the shaft.With this arrangement, the shaft can be pressed through the bore 31b in the slide body 31 and through the non-circular opening 45c in the sprocket to assemble the drive gear worm and a sprocket on the slide body. A lug 38c is provided on the shaft portion 38a of the vane support VS and arranged to engage stops 3land 31g on the sleeve 31a to limit angular movement of the vane support. These stops are angularly spaced apart with relation to the lug 38c so that the vane can rotate through slightly greater 1 800 to assure full closing of the vanes in either of two oppositely rotated positions.

The chain retainer guides 31c and 31 don each carrier normally maintain the first and second portions of the chains in meshing engagement with the respective sprockets at diametrically opposite sides and maintain a preset spacing of the auxiliary carriers along the chains. There are some occasions, for example when adjusting the length of the rod, that it is desirable to adjust the spacing between one or more auxiliary carriers.

For this purpose, provision is made for disengaging the sprocket on one or more of the auxiliary carriers from the bead chains to allow adjustment of the spacing between the auxiliary carriers after the rod is assembled. As best shown in Figs. 8 and 9, the slide body is formed with a bored 31h arranged to permit limited axially movement of the shaft 41 and worm 42 in a direction inwardly of the rod, that is to the left as viewed in Fig. 8 and 9. A means is provided to releasably retain the shaft in the position shown in Figs. 8 and 9, in which the sprocket is in meshing engagement with the chain. In the preferred embodiment shown, rounded protuberances 41g are provided on the shaft 41 at a location to engage the inner end of the bore 31h and normally maintain the shaft and sprocket to the position shown in Figs. 8 and 9.The shaft 41 is formed with a diametrically extending slot 41 h so as to be radially compressible in the region adjacent the protruberances 41g. With this arrangement, the shaft can be pressed axially inwardly from the position shown in Fig. 8 and 9 to disengage a sprocket from the bead chain, for example by either pressing on the outer end of the worm gear or by manually turning the vane carrier in a counterclockwise direction as viewed in Fig.

9. Thus, the sprocket can be shifted axially inwardly relative to the chain retainer guides 31 c and 31 do allow the bead chain to disengage from the sprocket so that the auxiliary carrier can be manually moved axially along the rod until the desired spacing relative to an adjacent auxiliary carrier is achieved. The sprocket is thereafter moved axially outwardly, as by applying torque on the vane support in a clockwise direction as viewed in Fig. 9, to re-engage the sprocket with the portions OC, and OC, of the bead chain.

In the adjustable rod using telescoping rod sections, the slide bodies must not only be adapted for sliding on the inner rod section or the outer rod section, but also where the two rod sections overlap as shown in Fig. 8. The guide walls 32a, 32b and 33a, 33b diverge outwardly from their bases at a shallow angle of the order of 50 and, in order to allow free movement of the slide bodies along the overlapping portions of the inner and outer rods, the spacing between the guide walls 32a, 32b and 33a, 33b is made substantially greater than the combined thickness of the upper and rear wall portions of the rod along opposite sides of the slot.In order to maintain the axis of the vane supports substantially vertical when the slides are in the overlapping portions of the rod sections H1 and H2, the upper inner guide wall 32a that engages the inside of the upper rear wall portion 24 is offset from the lower outer guide wall 33b that engages the outside of the lower rear wall portion 25 a distance slightly greater than twice the combined thickness of the overlapping rear wall portion of the rod. In order to maintain the vane support axis generally upright when the slides are supported on a single rod section such as an inner rod section H1 or the outer rod section H2, a lengthwise extending recess 33c (Fig. 8) is provided in the base of the lower groove in the slide body.The recess 33c has a width less than the combined thickness of overlapping lower rear wall portions of rod sections Ht and H2 to receive and ride on the upper edge of only a single rear wall portion. The lower recess is located laterally on the slide in relation to the upper guide edge 32a that engages the inner side of the upper rod wall portion to support the slide body on a single rod section H, or H2 with the vane axis substantially vertical. Since the transverse width of the groove 33c is less than the combined thickness of the lower rear wall portions of the overlapping rod sections, the lower rear wall portions of the overlapping rod sections do not extend into the recess but instead ride on the base of the lower guide groove.

The lead carrier LC comprises a slide body 55 having upper and lower grooves 55a and 55b for receiving the upper and lower rear wall portions 24 and 25 of the rod sections, to guide the lead carrier for movement along the rod. The lead carrier is moved along the rod by the traverse cord TC and the end caps C, and C2 are constructed and arranged to provide cord guides for the traverse cord. The end caps C, and C2 are of like construction, except that the end cap C, is dimensioned for reception in the end of the inner rod section H, and the end cap C2 is dimensioned for reception in the end of the outer rod section H2, and like numerals are used to designate corresponding parts of the end caps C, and C2.

The end caps are conveniently molded in one piece of a synthetic resin material and each include an end wall 61 adapted to overlie the end of the respective rod section and rear wall portions 62a and 62b adapted to overlie the inside of the rear wall portions 24, 25 at the respective rod section. The rear wall portions 62a and 62b are spaced apart to define a notch 62c therebetween having a width corresponding to the width of the slot S in the rod sections and adapted to be aligned therewith to allow a carrier such as the lead carrier LC to slide from the rod section into the notch 62c, to positively locate the lead carrier in the end cap.In order to accurately locate the upper and lower rear wall portions 24 and 25 of the rod section relative to the rear wall portion 62a and 62b of the end cap, the rear wall portions 24 and 25 of the rod sections are formed with notches 24a and 25a respectively (Fig. 1) that open at one end of the rear wall portions and the wall portions 62a and 62b of the end caps are formed with generallyT-shaped ribs 62d and 62e that are adapted to extend into the notches 24a and 25a to control the vertical spacing of the rear wall portions, and to overlie the rear sides of the rear wall portions of the rod adjacent the notches to laterally position the rear wall portions of the rod relative to the rear wall portions of the end cap.A latch 64 is formed on the end of a resilient arm integral with the end wall of the end cap and arranged to project into an opening 21 a in the top wall of the respective rod section, to lock the end cap to the respective rod section.

The traverse cord guides on the end caps C and C2 are best shown in Figs. 2 and 4 and comprise a pair of rollers 65 and 66 supported for rotation about axes that are vertically and horizontally offset to enable the traverse to be arranged for either right-hand or ieft-hand draw.

The traverse cord TC has one end portion TC, connected to the lead carrier LC and arranged to extend therefrom lengthwise of the rod and over the cord guide pulley 65 on the end cap on one end of the rod, and then downwardly to provide a first traverse cord operating portion TC 18 The traverse code also has a second portion TC2 which is also connected to the lead carrier and which extends from the lead carrier lengthwise of the rod over a cord guide pulley 65 at the other end of the rod then in a return run TC28 lengthwise of the rod and over a cord guide pulley 66 at the first mentioned head of the rod and downwardly to provide a second traverse cord operating portion TC2b.The operation portions TC1a and TC2b of the traverse cord are tensioned as by cord guides and, as will be seen, pulling on one of the traverse cord operating portions TC,a will move the lead carrier LC in one direction along the rod to an open position, and pulling on the other traverse cord operating portion TC2b will move the lead carrier in the opposite direction along the rod to a closed position.

An improved cord lock arrangement is provided for adjustably securing one end of the traverse cord to the lead carrier to facilitate adjustment of the length of the traverse cord with adjustments in the length of the header. As best shown in Figs.

2, 3 and 7, the lead carrier has upper and lower inner cord retainers 55d and 55e on the slide body 55 inside the rod which define a notch 55f therebetween, and a second pair of upper and lower cord retainers 55g and 55h on the slide body outside the rod which define a notch 55j therebetween. The inner and outer upper cord retainers 55dan 55g have upwardly opening generally keyhole shaped notches, and the inner and outer lower cord retainers 55e and 55h have downwardly opening generally keyhole shaped notches. As will be seen from Fig. 7, the keyhole shaped notches have a generally circular base portion dimensioned to snugly receive the traverse cord and a V-shaped outer portion that intersect the circular base portion on a constricted area to allow the traverse cords to be pressed laterally into the notches and retained therein.

The end of one of the traverse cord portions TC, is connected to the inner retainers and as best shown in Fig. 7, is snapped into the notch in the upper inner cord retainer 55d and then passed downwardly and snapped into the notch on the lower inner cord retainer 55e, with a knot K, provided at the end of the traverse cord portion TC,. The end of the other traverse cord portion TC, is passed through the notch 55f between the upper and lower inner cord retainers and laterally outwardly across one end of the slide body 55 and through the notch 55between the outer cord retainers, and is then looped around the upper and lower outer cord retainers 55g and 55h as shown in Fig. 3 and pressed into the notches therein.As will be seen from Fig. 3, the portion of the end of the traverse cord that passes between the upper and lower outer cord retainers crosses the portion of the traverse cord that passes through the notch 55j, to aid in retaining the traverse cord against detachment from the lead carrier. With this arrangement, the length of the traverse cord can be readily adjusted by merely pulling the end of the traverse cord TC2 out of the outer cord retainers 55g and 55h and then pulling outwardly on the traverse cord until it is adjusted to the desired length, after which the end is again looped around the upper and lower outer cord retainers and pressed into the notches therein.

The lead carrier LC is also connected to the operating chain OC to draw the auxiliary carriers therewith when the lead carrier is extended to close the blind, and the latch mechanism LM is provided to releasably latch the lead carrier to one of the end caps. The latch mechanism LM comprises a latch member 81 mounted on the lead carrier and a keeper 82 on the end caps. The latch member 81 comprises a latch body that is slidably mounted on the inner side of the lead carrier body 55 for limited movement relative thereto in a direction paralleling the length of the rod. The latch body 81 has an elongated opening extending therethrough defining the laterally spaced side walls 81a, first and second end walls 81 81c, and inwardly opening grooves 81d in the opposite side walls 81 a.The lead carrier 55 has resilient latch retaining lugs 55m extending laterally of the front side of the lead carrier body adapted to be received between the side walls 81 a of the opening in the latch body, and flanges 55n on the outer ends of the lugs adapted to extend into the recesses 81 din the latch body.

The lugs 55m have a length in a direction parallel to the length of the header which is short as compared to the length of the opening 81 a so that the latch body can slide relative to the lead carrier body in a direction paralleling the length of the rod between a first position in which the first end 81 b of the opening engages the lugs 55m as shown in Fig. 5 and a second position in which the second end 81 c of the opening engages the lugs 81run as shown in Fig. 6.A guide rib 55p is also provided on the forward face of the lead carrier body and arranged to guidably engage the side walls 81a on the latch body, and the end 81 c of the latch body is recessed to pass over the rib 55e during movement of the latch body from its first position to its second position. The rib 55p has a length which is long as compared with the transverse width of the slot and guides the latch body for sliding movement and effectively prevents tilting movement of the latch body relative to the slide body until the latch body reaches its second position.The lugs 55m are laterally resilient and, when the body reaches its second position, it can tilt a limited amount relative to the slide body in a direction crosswise of the header, the lugs 55m being laterally compressed during such tilting to resiliently urge the latch member back to a position in which the elongated slot is aligned with the rib 55p.

The latch body is connected to the operating chains in a manner such that tension on the operating chain normally urges the latch body to its first position relative to the lead carrier. As best shown in Fig. 1 and 11, the latch body has semicircular inner and outer wall portions 8land 81g that define an arcuate chain guide groove therebetween for receiving an end loop OCL of the operating chain OC. Latch noses 81 h are formed on the ends of the outer wall portion 81 g for engagement with the aforementioned keeper 82 on the end cap. The keeper 82 comprises a resilient blade like member having one end formed integrally with the end wall 61 of the end cap. The blade extends generally lengthwise of the rod and has an opening 82a adjacent at the free end adapted to receive a latch nose 81h on the latch body.The blade portion 82 is positioned in the path of travel of the nose portion 81 h on the latch body and when the lead carrier moves into the notch 62c on the end cap, the latch member is in its first position on the lead carrier and the arcuate lead face on the outer wall 81g of the latch member cams the keeper member upwardly until it passes over the nose portion 81 h. The tension on the operating chain normally urges the latch body to its first position on the lead carrier and the keeper 82 normally operates to retain the lead carrier in its extended position.

However, when the lead carrier is retracted by the traverse cords, the lead carrier moves relative to the latch member until the latch member reaches its second position. At that time, latch member can tilt relative to the lead carrier as shown in Fig.

6 and release engagement with the keeper.

The operating chain has portions OC, and OC2 that extend from the looped end OCL lengthwise of the header to the other end thereof, and provision is made for moving the chain portions OC, and OC, longitudinally relative to each other to effect rotation of the vane supports. As best shown in Fig. 12, the chain portions OC, and OC, extend over chain guides 85a and 85b on the end cap to downwardly extending operating portions OC18 and OC,, respectively.The chain guides 85a and 85b are vertically and horizontally offset from each other to vertically separate the chain portions OC, and OC, and to horizontally separate the chain portions Oc1a and Or,,. The operating portions C1a and Oc2a are conveniently connected in a loop by a bead chain connect to prevent pulling of one end of the operating chain out of the rod.As previously described, the auxiliary carriers are connected to the chain portions OC, and OC, at spaced locations therealong corresponding to the desired spacing between the centres of adjacent vane and, when the lead carrier LC is moved from an open position adjacent one end of the rod to a closed position adjacent the opposite end of the rod, it draws the looped end OCL of the bead chain therewith and pulls the auxiliary carriers along the rod while controlling the maximum spacing between adjacent auxiliary carriers.When the lead carrier is latched to the end cap in the closed position of the blind, pulling on one or the other operating portions OC18 or OC2a of the chain will move the chain portions OC, and OC, in relatively opposite directions and rotate the vane supports accordingly.

When the blind is in an open condition, the operating portions OC, and OC, of the bead chain form loops between adjacent carriers. If the operating portions of the bead chain C1a or OC2a are pulled when the blind is in a partially or fully opened condition, the slack loops in the chain portions OC1 and OC, sometimes become entangled or looped around other parts.

A chain locking device 91 is provided for locking the chain portions OC, and OC, against longitudinal movement when the carriers are retracted to open the blind. The locking device 91 comprises a body having chain guide passage means 91 a therein for guidably engaging the first and second chain portions for movement in relatively opposite directions. In the embodimerit illustrated, the locking device is in the form of a sleeve having a single guide passage for both the first and second chain portions, with the internal opening in the sleeve sufficiently greater than twice the cross-section of the bead chain to allow the chain portions OC, and OC, to pass in relatively opposite directions therethrough. The sleeve can have a circular cross-section as shown or an oblate cross-section, if desired.It is also contemplated, that separate guide passages could be provided in the device 91 for the chain portions OC, and OC2. In order to facilitate guiding of the chain portions longitudinally therethrough, the guide passage means has a length somewhat greater than the pitch of the beads along the chain. The chain guide passage means is arranged to maintain the first and second chain portions passing therethrough spaced apart a distance substantially less than the pitch diameter of the sprockets on the auxiliary carriers to lock the first and second chain portions to the sprocket on the auxiliary carrier, when that carrier is retracted into engagement with the chain locking device.The chain locking device is preferably arranged to engage the chain portions OC1 and Or, at a location adjacent one end cap such as to engage the sprocket on the adjacent end auxiliary carrier. However, it is contemplated that the chain locking device could also be arranged to engage the chain portions OC, and OC, at other locations intermediate adjacent ones of the auxiliary carriers. The locking device is conveniently arranged so that it is supported solely by the chain portions OC, and OC2.

However, it is also contemplated that the locking device could be supported on the end cap, provided it guides the chain portions OC, and OC, in the manner described above. When the locking device is located adjacent one end cap, a stop or shoulder 95 on the end cap engages one end of the locking device and limits movement of the locking device during retraction of the carriers.

Thus, as the carriers are retracted, the sprocket on the adjacent end carrier in the rod moves to a position adjacent the other end of the locking device. If one or the other of the operation portions OC18 or OC2a of the chain is pulled while the carriers are retracted, the locking device 91 draws the chain portions OC, and OC, part way around the periphery of the sprocket on the adjacent auxiliary carrier to lock the chain portions to that sprocket and lock that sprocket against rotation. As will be seen from Fig. 12, the end 91 b of the chain locking device adjacent the sprocket is preferably sufficiently thin to extend into the space between adjacent beads when the chain portions extend transverse to the end 91 b, as occurs when a sprocket is closely adjacent the end 91b.

The chain locking device not only operates to lock the chain portions OC, and OC, when the auxiliary carriers are fully retracted, but it also provides a chain locking function when the lead carrier is not locked in its extended position. If the lead carrier is not locked in its extended position, a pull on one or the other of the chain operating portions C1a or OC2a will tend to retract the auxiliary carriers until the end auxiliary carrier engages the locking device. When the lead carrier is locked in its extended position on the rod, the chain portion OC, and OC, pull the end auxiliary carrier away from the locking device and the chain portions can then pass relatively freely through the chain guide passages.

From the foregoing it is thought that the construction and operation of the vertical blind mechanism would be readily understood. The sprocket on one auxiliary carrier is assembled onto the drive shaft and onto the portions OC, and OC2 of the operating chain at a location spaced from the loop portion OCL of the chain to provide the desired spacing of that auxiliary carrier and the vane supported thereby from one end of the rod, when the lead carrier is latched to the end cap on that end of the rod, and the sprockets are assembled on the other auxiliary carriers and on the portions OC, and OC, of the bead chain at spaced locations therealong corresponding to the desired spacing of adjacent vanes along the rod.The number of auxiliary carriers varies with the overall length of the rod and in the adjustable header construction shown, it is contemplated that auxiliary carriers can be removed from the bead chain if the header is shortened. In some installations, for example if the header is shortened a distance less than the spacing between the auxiliary carriers or a multiple thereof, then one or more of the auxiliary carriers can be adjusted along the bead chain while the carrier is assembled on the rod. This is achieved by shifting the drive shaft 41 on the auxiliary carrier axially to disengage the sprocket from the bead chain, followed by shifting the drive shaft 41 on the auxiliary carrier axially to disengage the sprocket from the bead chain, followed by shifting of the carrier along the rod and re-engagement with the sprocket with the bead chain.The blind mechanism can be opened and closed by operating the traverse cords TC which moves the lead carrier along the rod between an open position adjacent one end of the rod to a closed position adjacent the other end of the rod. The latch mechanism LM on the lead carrier engages a keeper on the end housing to releasably latch the lead carrier in a closed position. When the lead carrier is moved along the rod to a closed position, the looped end OC, of the operating chain is drawn with the lead carrier and this pulls the auxiliary carriers along the rod and controls the spacing between adjacent ones of the auxiliary carriers. When the lead carrier is in its closed position latched to the end cap on one end of the rod, the operating portions OC1a and OC2a of the operating chain can be drawn to move the chain portions OC, and OC, longitudinally in relatively opposite directions to drive the sprockets and rotate the vane supports. The slip clutch between the sprocket and the drive shaft in conjunction with the rotation stops on the vane supports, enables rotation of all of the vane supports on the rod to be synchronized by pulling the operating chain in one direction until all of the vane supports engage the rotation stop.The speed reducing drive between the sprocket and vane supports provides a very accurate angular adjustment of the vane supports and further reduces the force required to pull the operating chain. Opening of the blind is effected by pulling on the draw cord in a direction to move the lead carrier away from the end of the rod. The latch member remains in engagement with the keeper 82 until the lead carrier moves relative to the latch member to its second position relative to the lead carrier at which time the latch member can tilt relative to the lead carrier and disengage the keeper. Continued movement of the lead carrier along the rod causes the lead carrier to push the auxiliary carriers together and toward the other end of the rod to an open position.

When the blind is in an open condition, operation of the operating claim is effectively prevented by the locking device 91. Location of the slot at the rear side of the rod conceals the slot and the internal blind operating mechanism from view from the front or under side of the rod. Further, with the slot located at the rear of the rod, the bottom wall of the rod underlies and supports the operating chain and traverse cord, even when there are slack loops in the chain as occurs when the blind is open.

Claims (24)

Claims

1. A vertical blind mechanism comprising a horizontal rod having a lengthwise extending slot and a track along the slot, a number of auxiliary carriers mounted on the track for movement along the rod and extending through the slot, each auxiliary carrier including a vane support for turning about an upright axis and a sprocket mounted for axial rotation inside the rod and connected to the associated vane support by way of drive means for turning the latter, a flexible operating chain having first and second parallel portions extending inside and lengthwise of the rod, each auxiliary carrier having chain guide means for respectively retaining the two chain portions in meshing engagement with opposite sides of the associated sprocket, traverse means associated with one end of the chain portions operable to move the one end of the chain portions along the rod to an extended position in which the chain portions limit maximum separation between adjacent auxiliary carriers and means associated with the other end of the chain portions for moving the chain portions lengthwise in opposite directions for rotating the sprockets to turn the vanes.

2. A vertical blind mechanism according to claim 1 wherein the drive means includes a slipping clutch between each sprocket and its associated vane support, and a stop for limiting turning of each vane support.

3. A vertical blind mechanism according to claim 2 wherein the slipping clutch comprises a non-circular opening extending through each sprocket, the drive means including a shaft having a diametrically compressible portion extending into the opening in the sprocket and a protuberance on the periphery of the diametrically compressible portion engageable with the non circular opening in the sprocket to provide slipping drive.

4. A vertical blind mechanism according to claim 3 including means on the outer periphery of the diametrically compressible portion for engaging one side of the associated sprocket to limit axial movement of the sprocket relative to the shaft.

5. A vertical blind mechanism according to any one of the preceding claims wherein the rod comprises inner and outer telescopically adjustable rod sections to enable adjustment of the overall length of the mechanism.

6. A vertical blind mechanism according to any one of the preceding claims, including means mounting the sprocket on at least one of the auxiliary carriers for limited axial movement relative to the chain guide means between one position in which the chain guides are operable to retain the chain portions in meshing engagement with the sprocket and another position in which at least one of the chain portions can disengage from the sprocket to enable adjustment of the spacing between the respective auxiliary carrier and an adjacent auxiliary carrier, and means manipulable from outside the rod for moving the sprocket between the two positions.

7. A vertical blind mechanism according to any one of the preceding claims wherein the drive means includes speed-reducing gearing between each sprocket and its associated vane support.

8. A vertical blind mechanism according to any one of the preceding claims wherein the slot extends along the rear side of the rod, and the drive means includes a shaft mounted on each auxiliary carrier for rotation about a generally horizontal axis transverse to the rear side of the rod, the shaft having its inner end connected to the associated sprocket and its outer end connected by right angle gearing to the associated vane support.

9. A vertical blind mechanism according to claim 8 wherein the rod comprises telescopically adjustable inner and outer rod sections, the slot extends along the rear side of the inner and outer rod sections and the track comprises upper and lower wall portions above and below the slot in the respective rod sections, the auxiliary carriers each including a slide body having upper and lower grooves with inner and outer guide walls spaced apart to loosely receive the wall portions on the inner and outer rod sections where the rod sections overlap with the generally horizontal shaft located between the upper and lower grooves and the upper inner guide wall and the lower outer guide wall being offset from each other in a direction perpendicular to the shaft axis a distance to maintain the vane axis substantially vertical when the inner upper guide wall engages the inner side of the upper rear rod wall portion of the inner rod section and the outer lower guide wall engages the outer side of the lower rear rod wall portion of the outer rod section where the inner and outer rod sections overlap, the lower groove having a lengthwise recess in the base of the groove between the inner and outer lower guide walls, the width of the groove being less than the combined thickness of the lower rear rod wall portions on the inner and outer rod sections to guidably receive the lower rear rod wall portion on only a single one of the rod sections, the recess in the lower groove being located in relation to the upper inner guide wall to maintain the vane axis substantially vertical when the upper inner guide wall engages the inner side of the upper rear rod wall portion on a single rod section.

10. A vertical blind mechanism according to any one of the preceding claims wherein the traverse means includes a lead carrier mounted for movement along the rod, means on the lead carrier engaging the said one end of the chain portions, and means for releasably retaining the lead carrier in a pre-selected extended position along the rod.

11. A vertical blind mechanism according to claim 10 wherein the lead carrier has mounted on it a chain return guide, the operating chain being looped around the chain return guide to form the two parallel chain portions.

12. A vertical blind mechanism according to claim 11 wherein the chain return guide is mounted on the lead carrier for limited movement relative thereto in a direction lengthwise of the rod between two positions on the lead carrier, and latch means on the chain return guide is operative to engage a latch keeper located at a fixed position on the rod to retain the lead carrier at this position when the chain return guide is in one position on the lead carrier and is operative to disengage the latch keeper to release the lead carrier when the chain return guide is in the second position on the lead carrier.

13. A vertical blind mechanism according to claim 12 wherein the chain return guide is supported for tilting relative to the lead carrier to release the latch means from the latch keeper when the chain return guide is in its second position on the lead carrier, and including means restraining the chain return guide against tilting relative to the lead carrier when the chain return guide is in its first position on the lead carrier.

14. A vertical blind mechanism according to claim 13 wherein the latch keeper is resiliently yieldable in a direction laterally of the rod and the latch means includes a cam engageable with the latch keeper to cam the keeper laterally when the lead carrier is moved from its first to its second position.

15. A vertical blind mechanism according to any one of claims 11 to 14 wherein the chain return member has semi-circular inner and outer chain guide walls defining a U-shaped chain guide passage therebetween, around which the operating chain is looped.

16. A vertical blind mechanism according to any one of the preceding claims wherein the track comprises portions of the wall of the rod along opposite sides of the slot, the wall portions having respective notches opening at one end and the rod end housing has corresponding rib portions extending into the notches to control the width of the slot at that end of the rod.

17. A vertical blind mechanism according to claim 16 wherein the housing wall has a slot extending into one end and aligned with the slot in the rod to receive a carrier.

18. A vertical blind mechanism according to any one of claims 11 to 1 5 and further comprising a chain locking device inside the rod at a location in the path of movement of the sprocket on one of the auxiliary carriers when it is retracted toward the end of the rod, the chain locking device having chain guide passage means therein for guidably engaging the two chain portions for movement in relatively opposite directions therethrough, the chain guide passage means maintaining the two chain portions passing therethrough spaced apart a distance substantially less than the pitch diameter of the sprocket on the auxiliary carrier to lock the two chain portions to the sprocket on the auxiliary carrier when it is retracted into engagement with the chain locking device.

19. A vertical blind mechanism according to claim 18 and including rod chain guides on the end of the rod towards which the auxiliary carriers are retracted, the guides engaging the two chain portions at that end of the rod, the chain locking device being located between the rod chain guides and the sprockets on the auxiliary carrier adjacent that end of the rod.

20. A vertical blind mechanism according to claim 18 or claim 19 wherein the chain locking device is supported solely by the two chain portions.

21. A vertical blind mechanism according to any one of claims 18 to 20 wherein the chain locking device comprises a tubular sleeve having an internal opening of the size greater than the combined cross sections of the two portions.

22. A vertical blind mechanism according to any one of claims 18 to 21 wherein the chain is a bead chain and the chain locking device has portions at the end adjacent the sprocket on the adjacent auxiliary carrier adapted to extend between adjacent beads on the two chain portions when they extend transversely to that end of the chain locking device.

23. A vertical blind mechanism according to claim 21 including an end cap on one end of the rod and chain guides for guiding the two chain portions from the rod to respective downwardly extending chain operating portions, the chain locking device being supported between the end cap and the adjacent end one of the auxiliary carriers, and having one end for engagement with the sprocket on the end auxiliary carrier and the other end for engagement with the end cap when the carriers are retracted, the sprocket on the end auxiliary carrier being spaced in a direction lengthwise of the rod from the chain locking device when the carriers are extended.

24. A vertical blind mechanism substantially as described and as illustrated with reference to the accompanying drawings.