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

Abstract: A control and suspension system for a retractable covering mounted on a rotating element includes an apparatus for mechanically limiting over-extensions of the covering and an apparatus for mechanically limiting over-retractions of the covering. The control and suspension system also includes an apparatus to compensate for any undesirable skewing of the covering that might occur. Finally, the control and suspension system also includes a bottom rail that attaches to the bottom of the covering by trapping a portion of the covering between a compression plate and a bottom plate.

Abstract: A lift control device for a roller shade includes a support rod having one end containing an insert socket, a spring mounted on the support rod, a roller cap rotatably mounted on the support rod and containing a retaining opening to secure the spring therein such that the spring is rotated by the roller cap, and a follower spool secured on the roller cap to rotate therewith.

Abstract: A shade positioning system which employs a wrap spring clutch system includes a shade operator, a shade roller, and an idle end bracket for supporting the shade roller when mounted. The shade operator includes a self-lubricating central stud around which a helical coil spring is wrapped, a manually operated pulley mounted on the wrap spring, and a support bushing to ensure positive engagement of the aforementioned elements. The central stud is composed of a plastic or metal, which allows the smooth rotation of the wrap spring around the stud. The tangs of the wrap spring project substantially radially outward from the spring central axis, and are shaped to accommodate for the coefficient of friction between the stud and the spring. A first preferred spring construction allows for decreased spring surface area to contact the stud. A second preferred spring construction allows for an increased spring surface area to contact the stud.

Abstract: A break away operating cord system for retractable coverings for architectural openings such as windows, doors, arches or the like includes a mounting plate to which an operating cord is attached and wherein the mounting plate is releasable from the remainder of the control system for the retractable covering allowing the operating cord to be separated from most of the covering to avoid injury to a child or infant whose head might be trapped within the closed operating cord loop.

Abstract: A control cord end security device includes a base plate for mounting on a wall surface. A guide member is disposed on the base plate for slidably retaining an end loop of a cord of a window covering such as a blind. A cover plate is removably affixed to the base plate and covers the guide member and respective end loop of the cord. The guide member comprises a semicircular wall defining a generally U-shaped channel for slidably retaining and guiding a respective cord of the window covering. Preferably, the guide member includes a flange portion disposed distal the base plate. The flange portion abuts an interior surface of the cover plate such that an end loop of a respective control cord is prevented from binding between the guide member and the cover plate, even in the presence of slack in the control cord.

Abstract: An improved bearing mechanism works in conjunction with the control rod of a vertical blind system or a roller shade system to provide superior bearing and load handling capability. A conical bore has a plurality of grooves into the surface of the conical bore. A series of cylindrical rollers are supported within the grooves, and against a central rotational member having a conical surface for bearing against the rollers. A set screw is used to control the seating of the central rotational member within the conical bore, is used to make up any tolerance created through the manufacturing process, and can be used to increase the tension necessary to hold a roller shade in place.

Abstract: An inventive bottom stop mechanism uses one of the lift cords to operate. While the cord is unwinding from the shaft, the cord leaves the shaft along a line tangent to the shaft. As the last turn of cord is unwound from the shaft, and the point of attachment of the cord to the shaft passes that point of tangency, the angle of the cord with respect to the shaft changes. This change in angle of the cord is used to raise a pawl which engages a ratchet wheel to stop the shaft and prevent further rotation in that direction. When the direction of the shaft is reversed to again start winding the cord thereupon, the cord angle returns to its prior value, releasing the stop.

Abstract: A clutch mechanism adapted to facilitate disengageable manual operation of a roller door or shutter comprising a chain pulley wheel journalled for rotation about the axis of a first shaft permanently engaged with or common with the main shaft about which the door or shutter is stored but not constrained to rotate with the first shaft at times when such shaft is driven other than manually; a clutch disc journalled alongside the chain pulley wheel on the same axis and similarly free to rotate independently of the first shaft; a linking pin on the chain pulley wheel between the chain pulley wheel and the clutch disc to link the chain pulley wheel to the clutch disc such that rotation of one causes rotation of the other about their common axis; biasing springs on the clutch disc constraining the free end of the linking pin to bias the linking pin into an equilibrium linked position; the biasing springs being sufficiently weak that a light tug on the chain about the chain pulley wheel will allow limited relative r

Abstract: The blind comprises a sheet wound on a tube which is supported at one end by a drive assembly and at the opposite end by an idle end mounting. The drive assembly is operated by a ball cord which is engaged over a flangeless pulley which, in turn, has an internal notch to pass over a braking spring. The idle end mounting includes a spring which holds the tube in position and which acts between a spigot and a shaft, both of which are keyed together. The spigot rotates on a drum which is mounted on a ribbed metal bracket, and a similar bracket supports the drive assembly.

Abstract: A release brake shade operator for a window covering has a stationary member, a movable member movable relative to the stationary member, and a hub which is movable relative to the stationary member and the movable when not restrained. Preferably the hub is a tube or solid cylinder. A spring having a selected diameter is fitted between the stationary member and the movable member and surrounds a portion of the hub. A first tang at one end of the spring is attached to the stationary member and a second tang at an opposite end of the spring is attached to the movable member so that one tang can be moved relative to the other tang to increase the diameter of the spring. The spring is sized and positioned so that the spring will press against the outside surface of the hub when in a relaxed condition restraining the hub and attached to the roller shade or lift cords.

Abstract: A garage screen is provided including a screen assembly having a cylinder rotatably coupled adjacent to a top edge of a sliding garage door with a spool mounted thereon. A rope is included having a first end connected to the spool and a second end for manually deploying the screen when desired.

Abstract: A blind cord safety device for use in controlling an adjustable blind having a looped control cord and a looped control chain by enclosing the loops has housing within which are disposed a rotatable wheel adapted to engage the chain loop thereabout and a U-shaped cord loop receiver adapted to receive the cord loop in a peripheral groove formed thereon. The receiver is mounted within the housing so as to permit limited longitudinal but not lateral movement of the receiver within the housing. A spring is disposed within the housing between the receiver and the housing top so as to normally urge the receiver away from the housing top so as to avoid slack in the cord as a result of the cord stretching over time as a result of use.

Abstract: The operating device has an input shaft (20) which by one end is connected with a driving arrangement with a rotatable wheel (17) for receiving an endless cord (8), and which by the other end is coupled to an output shaft (14) which is connected in a rotationally locked manner with the screening arrangement. The input shaft (20) is connected with the output shaft (14) via a transmission shifting device, in particular a planet gear (21). Between the transmission shifting device and the output shaft, a mechanism is engaged for limitation of the transferred driving torque. This mechanism is constituted by a sliding clutch having a first coupling part (25) in connection with the transmission shifting device (21) and a second coupling part (26) in connection with the output shaft (14). The first coupling part (25) may have a toothed shaft (24)and the second coupling part (26) a slotted and toothed rim (27), or vice versa.

Abstract: An operator for a window covering has a stationary member and a hub which is moveable relative to the stationary member when not restrained. Preferably these members are a tube or solid cylinder within a tube. A spring having a selected diameter is fitted between these two generally cylindrical members. A first tang at one end of the spring is attached to the stationary member and a second tang at an opposite end of the spring is attached to a movable member so that one tang can be moved relative to the other tang to increase or decrease the diameter of the spring. The spring is sized and positioned so that the spring will press against the inside surface of the hub when in a relaxed condition. When the tangs of the spring are moved relative to one another to reduce the diameter of the spring, the spring does not restrain movement of the moveable member. In a present preferred embodiment there is a roller attached to the hub at one end.

Abstract: The roller blind (100) detachably fastened to a winding axis (50) can be rolled up on to and unrolled from the winding axis with the aid of pull cords, in which case the pull cords (20, 120, 220) are constructed in the form of U-like routed pull cord pairs (21, 121, 221) passed through guide rings (30, 31, 130, 131, 230, 231) with concentric pull cord connecting sections (24, 124, 224) proceeding parallel to the longitudinal axis of the winding shaft (50) and located on top of each other, which are seized for the rolling up and the unrolling operation of the window shade by a pull cord entrainment means (60) secured concentrically to the circumference of the winding axis (50).

Abstract: An automatic-locking mechanical drive construction for raising and lowering a window covering, including a fixed cylindrical shaft, a rotary drive member mounted to rotate about an axis with respect to the shaft, and a rotary driven member turnable with respect to the shaft and about the axis of the drive member. The drive and driven members have pairs of facing, abuttable walls effecting a two-directional, lost-motion rotary driving connection between the members, and a helical coil spring is disposed on the shaft, so as to frictionally seize it, and selectively lock thereon. The spring has a radially-projecting shoulder intermediate its ends. Spaced-apart shoulders on the driven member are individually engageable with the projecting shoulder on the spring whereby the spring normally prevents turning of the driven member in either of opposite directions.

Abstract: An electric window blind comprises a driving member capable of being actuated by an action rod to cause the rotary wheels to engage the transmission wheels at the time when the power outage takes place. The rotary wheels can be therefore actuated manually so as to keep to electric window blind in an operating condition in the event of a power interruption.

Abstract: A clutch-brake type roll blind is provided with a wind-up spring for rolling up a screen on a tube and a weight bar free from a pulling string, being suitable for use with a tall window extending from floor to ceiling. The roll blind includes a rotary shaft fitted in the tube for rotation therewith and projecting therefrom, a pulley rotatably mounted on the rotary shaft, and an endless ball chain drivingly hung down from the pulley. The pulley can rotate the tube only when the ball chain is pulled down in the direction in which the screen is rolled down from the tube.

Abstract: A bi-directional sprang clutch further including a ratchet and pawl so as to permit substantial torque to be transmitted to the shade roller only in one direction. In the other direction, the roller is nearly free to rotate so that the weight of the shade material depending from one side of the roller exerts a torque on the roller which prevents reverse rolling.

Abstract: A spring clutch mechanism for the operation of roller shades and other rollable items. This clutch mechanism is designed to release for raising the shade so as to minimize effort. Whereas prior art clutch mechanisms for roller shades are intended not to slip, or to slip only to save themselves, in this case, lowering of the shade is accomplished by overriding the clutch, causing it to slip. The clutch can be adapted easily to accommodate know shade weights. The inventive design provides superior operating characteristics and, because the clutch can be built with as few as two parts, much lower cost.

Abstract: The invention relates to closures for doorways or other similar access openings and more specifically to side coiling doors in which the closure curtain forming the door is a flexible, fabric like material that is wrapped onto or coiled onto and unwrapped from or uncoiled from a vertically disposed, rotatably supported, relatively short barrel with only the upper edge portion of the door being engaged by and supported by the barrel. The upper edge of the flexible curtain forming the door is maintained on the barrel by the use of a unique spring tensioning assembly engaged with the barrel and an interlocking tracking member between the barrel and convolutions of the flexible curtain. The upper edge of the flexible curtain forming the door is supported, guided and moved along the upper edge of the opening by a track and cable system that is associated with the door opening and vertical barrel to enable effective opening and closing movement of the side coiling doors.

Abstract: A spring clutch assembly with reduced radial bearing forces is described. The clutch includes a shaft, at least first and second helically wound axially mounted springs for making frictional contact with the shaft, and engaging means corresponding to each of the first and second springs for selectively applying a tightening force to one end of each of the springs in order to prevent rotation with respect to the shaft. Each of the engaging means is radially and symmetrically disposed along the shaft for eliminating radial bearing force induced by the spring ends.

Abstract: An operator for a window or like shade serves to turn a shade roller to a new desired position as the result of a torque applied from a manually operable source, such as a chain operated wheel. The device includes a helical spring that is seated within a fixed bushing with its outer surface in contact with an inner cylindrical surface of the bushing. When torque is applied from the manually operable source, one overlapping end of the spring is moved away its other end to reduce the spring diameter and hence release any frictional engagement of the spring with the bushing, thus allowing the torque to rotate the spring, which rotation is transmitted to the roller. However, when no such manually applied torque is present, the spring and the roller remain effectively locked in position. Any torque applied from the roller due to the weight of a partly lowered shade acts to tend to increase the spring diameter and thus to ensure a binding frictional engagement between the bushing and the spring.

Abstract: An automobile window shade system comprises a frame (20) formed of hollow horizontal elements (20a through 20d) and hollow vertical elements (22a through 22f) interconnected by T-shaped connectors (24a through 24f). The frame is installed inside the automobile and contains a beaded cord (128) with beads or expansions (130) rigidly attached to the cord. Two adjacent shades (142 and 144) are made of a light-impermeable flexible material and are attached to a yoke. An embodiment with a beaded thread (128) and an expandable spring-loaded C-shaped portion of the yoke makes it possible to shield and unshield windows selectively by fixing the yoke and pulling the beaded cord through the spring-loaded C-shaped hole of the yoke. As a result, the shades are shifted to a new initial position and then moved from this new position.

Abstract: The disclosed drive uses a ball chain and sprocket for adjusting a wind-up blind and a locking device activated by the ball chain into cooperation with the sprocket for blocking the sprocket and locking the drive, avoiding any large stress in the chain.

Abstract: A device for transmitting a drive force between a flexible element, such as cord, and a first rotatable, cylindrical body, said flexible element is trained around the casing surface of the body through a pre-determined angle, wherein a second cylindrical body is arranged with a rotating shaft parallel to that of the first, along which the flexible element is trained in opposing direction, said both bodies, preferably provided with at least one groove for receiving said flexible element, are embodied and/or placed such that the bodies rotate without slippage between flexible element and both cylindrical bodies.

Abstract: An improved winding apparatus for a roller blind is disclosed. The winding apparatus includes a clutch mechanism provided between the winding roller and the cord pulley for transmitting rotation of the pulley to rotation of the winding roller. The clutch mechanism is arranged to prevent the urging mechanism from rotating the winding roller when the cord is not handled. It also allows the pulley to rotate a predetermined angle in a screen lifting direction when the cord is operated to lift the screen. At this point, the urging mechanism is permitted to rotate the winding roller in the screen lifting direction. Additionally, when the pulley is rotated by the cord in a screen lowering direction the pulley is first allowed to rotate freely for a predetermined angle. Thereafter, the screen lowering motion of the cord is transmitted through said pulley to said winding roller to lower the screen.

Abstract: A vertical blind vane tilt control lock for manually locking in a rigid position the vane tilt chain actuating mechanism for vertical blinds to prevent undesired movement of the vertical blind vanes by wind or air passing through the vanes. The control chain locking device is rigidly fastened to a wall surface near the chain actuator so that it can be manually engaged or disengaged as desired. The chain control lock includes one or two locking slots so that both sides of the vane tilt actuating chain are held taut from the vertical blind actuating pulley to prevent movement of the vanes.

Abstract: A rolling or overhead door assembly is disclosed comprising a shaft having an external thread bounded by a first and second bearing surface, a hub screwingly engaging the shaft and adapted to travel along the shaft, a first sprocket rotatably mounted on the first bearing surface and operably connected with a take-down device for unrolling a flexible door and a second sprocket mounted on the second bearing surface and operably connected with a take-up roller for rolling up the door, and abutments on opposite sides of the first and second sprocket. Upon rotation of the shaft the hub advances along the shaft and frictionally engages the first sprocket until the first sprocket and shaft rotate together and upon counter rotation of the shaft the hub advances back along the shaft and frictionally engages the second sprocket until the second sprocket and shaft rotate together.

Abstract: A pulling device for a roll shaft for roller blinds or screens comprises a housing, a chain pulley situated in the housing and a chain slung around the pulley. The chain is formed by a cord with a number of beads distributed at regular interval along the length. The pulley is provided with a central channel and a series of notches at the periphery to receive the cord portion and the beads of the chain, respectively. The chain is readily pulled to drive the pulley and, in turn, the roller shaft, to wind up or to unwind a roller blind or screen. When the pulling force is released the pulley will be automatically braked by means of the chain itself by the gravity of the roller blind or screen.

Abstract: A rolling shutter system employs a variable efficiency bi-directional drive mechanism which permits easy and quick raising of the rolling shutter while protecting against self-lowering of the shutter by reason of its own weight. The system also employs a novel operator for the bi-directional drive mechanism which is characterized by an easy and comfortable to grip bead string which also is attractive in appearance. The bead string is trained about a sprocket wheel, and an overload slip clutch is provided between the sprocket wheel and worm gear drive to limit the amount of force that can be applied to the bead string during raising and lowering of the rolling shutter. Also provided is a novel shutter travel limit and locking device, a novel valance construction and a novel through the wall shaft assembly.

Abstract: In a device for controlling a roll-up curtain roller for a curtain to be placed in an opening, a pulley is linked to the curtain roller and has a race forming a lock slot for a driving rope, and a plate supports the pulley and is available for fastening the device to an end of a box in which the roller with the curtain thereon is housed. A guide has a center hole through which passes a grooved cylinder of the pulley, and is mounted on the pulley along the race in an intermediate position between the plate and the box. The guide is provided, on opposite sides, with a first and a second pair of slits through the rope can come out of either one or both of the pair of slits so that the device can be operated from either one or both sides of the opening in which the curtain is placed.

Abstract: A cloth curtain lift controller, which includes a driving wheel driven by a cord of beads to engage or be disengaged from a brake member by relative engagement with a ratchet wheel which is controlled by a stopper element to rotate in one direction. A torsion spring is mounted on a brake member with one end secured to the driving wheel so as to bias the driving wheel into engagement with the ratchet wheel. A driven cylinder is secured to the driving wheel to drive a cloth curtain scroll to raise or lower a cloth curtain.

Abstract: A rolling door mechanism employing an idler drive member freely supported about an idler roll of a roll door assembly. An adjusting element, for example, a coiled spring which surrounds the idler roll, accommodates differences in speed of the idler drive member and the idler roll. The adjusting element is connected at one end for rotation with the idler drive member and at the other end for rotation with the idler roll. In one preferred embodiment the coiled spring is tensioned during rotation of the idler drive member in one direction by drive means and this tension is released during rotation of the idler drive member in the opposite direction.

Abstract: The disclosed ball-chain drive for a wind-up blind has a chain-activated locking device that acts directly on the sprocket and remains effective even if the ball chain breaks or is jostled. The locking device in one form has such symmetry that the ball-chain drive is usable at either end of the wind-up blind.

Abstract: A blind assembly has an endless roll cord and an endless pull cord to avoid the cord storage problem.

Abstract: Drive unit for a vertical blind or the like, where the slats of the vertial blinds can be moved by an endless pull element, such as a pull chain. The drive unit has a housing (5) formed, for example, of plastic, an electric drive motor (6) placed in the housing (5), and a drive pinion or the like coupled to the drive motor, optionally by an inserted reduction gear. By enclosing of the drive components within the housing, a safe and unobtrusive drive unit is created. Preferred embodiments of the unit are constructed to enable the pull element to enter the housing through openings therein and be hung on the drive pinion. By this construction and the provision of control switches on the housing for operation of the electric drive motor, the drive unit is inexpensive and able to be retrofitted simply and versatily. Additionally, in an emergency, easy hand operation of the vertical blinds is still possible.

Abstract: The present invention provides a roller blind construction comprising a flexible blind which is windable for lowering and raising the blind. The blind has a downward weighting which increases as it is lowered and the construction further includes a conuterbalancing coil spring which products an upward pull increasing in direct relation to and neutralizing the downward weighting without lifting the blind.

Abstract: A positive drive for window shades and the like is characterized, first of all, by an opposed pair of channel-shaped tracks confining the right and left side margins of the shade and each also housing one run of an endless chain reaved under a pulley at the bottom and over a sprocket at the top. The bottom of the shade carries a rigid hem bar having eyelets in its ends sized to pass the chain but not a pair of stops carried by the latter that engage the hem bar and unwind the shade off the roller it is wound upon at the top when an exposed run of one of the chains is pulled. Right and lefthand one-way clutches are interposed between the sprockets and roller operative when the shade is lowered to disengage and permit relative rotational movement between the shade drive mechanism and the roller until the stops engage the eyelets in the hem bar. These same clutches engage when the shade is raised to link the drive mechanism and shade roller together for conjoint rotation.

Abstract: A shade operator includes a drive unit having a central stud forming the axis of rotation for the shade roller. A manually operable pulley is mounted on the stud, and is engageable with a coil spring clutch member mounted about the stud coaxial with the pulley. The shade roller is engaged by a bushing which is also mounted for rotation on the stud. The bushing is provided with a projection which engages the clutch spring due to the weight of the shade and causes the spring to further grip the stud to prevent rotation Operation of the pulley engages the spring such that its grip on the bushing is loosened, which allows the spring, bushing and shade roller to be driven by the pulley as desired to raise or lower the shade. Halting of pulley rotation allows the spring clutch to fully re-engage the stud to keep the shade at the new desired location.

Abstract: A lateral pull roll-up blind includes a drive housing member which is provided with lateral connecting elements which are situated within the outline of the driving wheel. These connecting elements, as well as compatible connecting elements of a carrier are distributed along a distribution circle in a distributing pattern rendering multiple angular repositioning of the housing member relative to the carrier possible. Even the other end of the lateral pull roll-up blind and the corresponding carrier are constructed in the same manner. The housing member is provided with a hollow pin on which there is mounted a clamping winding spring, while an entraining disc serving for the rotational entrainment of the associated end of the take-up shaft is rotatably mounted in the pin of the housing member. The entraining disc is drivingly connected with the driving wheel through actuating portions of the clamping winding spring.

Abstract: A shutter is provided which is moved up and down by the use of the urging force of a take-up spring for turning a take-up shaft that winds up a number of slats and the weight of the slats. These slats are mutually coupled vertically expandably and a number of slits are formed in expandable portions of individual slats. The shutter includes a slit open/close means for expanding and contracting the slats to open/close the slits.

Abstract: An elongate roller, movable back and forth transversely across the bed of a truck from one side thereof, has rolled thereon a cover sheet which is unrolled and rerolled during the back and forth movement to cover a load in the truck bed. Levers pivotally mounted at opposite ends of the truck carry the roller and are moved by hydraulic power cylinders controlled from inside the cab of the truck. A special chain and sprocket arrangement drives the roller, and a special elastic drawcord and backup plate arrangement at opposite ends of the truck bed secures and seals the cover sheet at such opposite ends of the truck bed.

Abstract: A mechanism for the roller of a roller blind, in which a housing has rotatably mounted therein a pulley over which a ball cord, passes, with two pieces of cord hanging down, one from each side of the pulley. The balls of the ball cord can be engaged in one of two U-shaped slots, to lock the cord. The U-shaped slots are each formed in a locking element which is designed as a component which can be fastened to the housing in either of two different positions, the locking part being arranged on the locking element in such a way that, in one or other of the two different positions, it always interacts with one or the other of the pieces of cord hanging down.

Abstract: A bead-chain drive system for operating and positioning a window shade comprises a roller having a window shade mounted thereon, the roller being urged by the weight of the window shade in a direction to lower the shade. The drive system further includes a sprocket for driving the roller that is driven by a bead-chain, trained about the sprocket. The bead-chain includes a chain length urged toward the sprocket by the weight of the shade applied to the roller and the sprocket. The drive system also includes a bead-chain retainer having a holding device operative to hold at least one of the beads of the chain length against movement toward the sprocket to position the window shade and from which the chain length can be easily freed upon movement thereof away from the sprocket.

Abstract: A manual operator for a coiling door has a reel mounted for free rotation on a shaft supporting drums to which the coiling door is secured. An endless flexible non-extensible element is mounted on the reel with a sufficient number of turns thereon for complete opening or closing of the door and the reel is secured to the adjacent one of the door supporting drums. The resilient non-extensible element is manually drawn to open or close the door and may be provided with hand holds to facilitate grasping thereof. A guide for the flexible non-extensible element may be secured adjacent the reel to guide the flexible non-extensible element onto and off of the reel.

Abstract: Ball cord lock intended to be used for roller blinds and comprising a cord pulley having an axially extending stub axle for receiving and retaining one end of a roller blind rod, an endless ball cord arranged around the cord pulley and in engagement therewith and which during operation windsup and unwinds respectively a blind attached to the roller blind rod, a lock housing formed by two complementary housing halves which housing constitutes journal for and encloses the cord pulley, a bracket which is connected to the lock housing and which is intended to be mounted at a window, and a U-shaped cord locking portion formed in the lock housing for catching and retaining one of the loops of the ball cord whereby the rotation of the cord pulley in one direction and accordingly unwinding of the blind in wound-up condition is prevented. The U-shaped cord locking portion is arranged immediately adjacent the periphery of the cord pulley under one of the freely suspending loops of the ball cord.