SPRING BRAKE WINDOW TREATMENT

Abstract

This document describes brake assemblies that may be useful for window treatments, such as motorized, spring-balanced window treatments, including spring-balanced blinds. The brake assemblies include wire brake springs formed into a plurality of coils. The plurality of coils may terminate in a reed assembly, where the reed assembly has a reed and a support portion. A support portion supports the reed when a force acts upon it (e.g., a spring force that tightens or loosens). The support portion greatly reduces the risk of the reed bending because the reed is supported at each of its ends. With less chance of bending at the reed, a smaller wire diameter can be used for the brake spring, resulting in less drag when it rotates in an actuated state.In the case of battery-operated blinds, the less drag there is, the longer the battery life will be.

Description

This application claims the benefit of provisional US patent application serial no. 63 / 067,210, filed on August 18, 2020, the description of which is incorporated herein in its entirety by reference. BACKGROUND A window treatment can be mounted in front of one or more windows, for example, to prevent sunlight from entering a space and / or to provide privacy. Window treatments can include, for example, roller blinds, Roman blinds, Venetian blinds, or curtains. A roller blind typically includes a flexible blind fabric rolled onto an elongated roller tube. Such a roller blind may include a weighted rod located at one bottom end of the blind fabric. The weighted rod allows the blind fabric to hang in front of one or more windows over which the roller blind is mounted. A typical window treatment can be mounted on a structure surrounding a window, such as a window frame. Such a window treatment may include brackets at opposite ends of this structure.The supports can be configured to operationally support a roll-up tube, allowing a flexible material to be wound and unwound. For example, the supports can be configured to support the respective ends of the roll-up tube. The supports can be attached to a structure, such as a wall, ceiling, window frame, or other structure. COMPENDIUM This document describes brake assemblies for window treatments that employ motorized roller tube systems. Motorized roller tube systems may include a roller tube for rolling up (and unrolling) a flexible member, such as a shade fabric. A housing may be arranged on the roller tube and contains a motor, logic controls for the motor, a drive shaft for rotating a disc connected to the roller tube via a disc shaft, and a brake assembly. The motor may use AC or DC power. Power may be supplied by cable or data. A brake assembly includes a mandrel, an input member coupled to the drive shaft and rotating around the mandrel, an output member coupled to the disc shaft and rotating around the mandrel, and a brake spring disposed on the mandrel.A brake spring described herein comprises a plurality of coils, a tongue extending from the plurality of coils, and a support portion extending from the tongue, wherein when the motor is not driven, the brake assembly prevents the flexible member from unwinding. Another brake assembly for a motorized winding system includes a mandrel and a brake spring disposed on the mandrel, wherein the brake spring comprises a plurality of coils, a tongue extending from the plurality of coils, and a support portion extending from the tongue, wherein, in a first rotational position, a force is exerted on the tongue, driving the spring back, causing the plurality of coils to squeeze the mandrel and prevent rotation between them. A brake spring for a motorized coiled tube system includes a plurality of coils, each having a tongue assembly at its end. Each tongue assembly comprises a radially extending tongue and a support portion extending from the tongue. The tongue is subjected to various forces acting upon it to exert tension on the plurality of coils. For example, the tongue may be acted upon by a first force, such as a locking force. Alternatively, the tongue may be acted upon by a second force, such as a driving force. The tongue is supported at two points from the point of incident tension to the point where the force is applied to the tongue. BRIEF DESCRIPTION OF THE FIGURES FIG. 1A is a perspective view of a motorized window treatment system. FIG. 1B is a perspective view of an example motor drive assembly for a motorized roll tube system with a portion of a housing removed. FIG. 1C is a perspective view of an example brake spring for the drive assembly of FIG. 1B. FIG. 2 is a perspective view of an example brake spring as described herein. FIG. 3 is a perspective view of a brake assembly as described herein for use in a motorized roll tube system. FIG. 4 is an exploded perspective view of the brake assembly of FIG. 3. FIG. 5 is a side elevation view of a brake assembly as described herein in a first rotating state. FIG. 6 is a cross-sectional view of the brake assembly from FIG. 5 to line 6-6. FIG. 7 is a side elevation view of a brake assembly as described herein in a first rotating state. FIG. 8 is a cross-sectional view of the brake assembly from FIG. 7 to line 8-8. Figures 9A-9B are perspective views of example brake springs as described in this document. FIG. 9C is a plan view of an example brake spring as described herein. DETAILED DESCRIPTION A motorized window treatment, such as a motorized roller tube or blind system, may comprise a roller tube and a flexible member or material, such as blind fabric, attached to the roller tube. The drive mechanism of the roller tube may cause it to receive or release the flexible material. A motorized window treatment may further include a drive assembly that can drive the roller tube (e.g., rotate the roller tube so that the flexible material rolls up and down on and off the roller tube). As the flexible member is wound onto the roller tube, the material of the flexible member can be formed into layers (or windings). Part of the flexible member may be wound onto the roller tube, and another part of the flexible member may hang from the roller tube (e.g., a hanging portion). When the hanging portion of the flexible member completely covers a window, the window treatment (e.g., a blind) is said to be closed. When the hanging portion of the flexible member is fully wound (e.g., completely wound onto the roller tube), the window treatment (e.g., a blind) is said to be open. As can be seen, there are multiple positions between open and closed, where each position has an associated hanging portion of the flexible member, with an associated weight that creates an associated load due to gravity. FIG. 1A illustrates a perspective view of an example motorized window treatment, such as a motorized roller blind 1. The motorized roller blind 1 may include a covering material 2 (e.g., a flexible material, such as blind fabric) wound around a roller tube 3. The roller tube 3 may extend from a first end 3a to a second end 3b. A longitudinal shaft 4 may extend from the first end 3a to the second end 3b of the roller tube 3. The roller tube 3 may be rotatably supported by mounting brackets 5, which may be attached to a structure adjacent to a window (e.g., a wall or ceiling) that may be covered by the covering material 2. The roller tube 3 may be constructed of any suitable material, such as, for example, aluminum, stainless steel, or plastic. A support bar 6 can be connected to a lower edge of the cover material 2 and oriented parallel to the lower edge of the cover material. The support bar 6 can be configured to overload the cover material 2. Rotation of the roll tube 3 around the longitudinal axis 4 can cause the cover material 2 to roll up or down from the roll tube to raise and lower the support bar 6. The motorized roller shutter 1 may comprise a motor drive unit 7 and a guide pulley 8 that can be configured to connect to one of the respective mounting brackets 5. The motor drive unit 7 may be located within, or otherwise coupled to, the first end 3a of the roller tube 3, and the guide pulley 8 may be coupled to the second end 3b of the roller tube. The motor drive unit 7 may include a motor (not shown) configured to rotate the roller tube 3 to adjust the cover material zwiznn / eznz / E / YiAi between a fully closed position and a fully open position, and may be configured to retain the cover material 2 in any position intermediate to the fully closed and fully open positions.The guide pulley 8 can be attached to the roller tube 3 (for example, at the second end 3b) to allow the roller tube to rotate relative to the mounting brackets 5 when the motor drive unit 7 rotates the roller tube. The motor of the motor drive unit 7 can be any suitable drive member, such as a DC motor, an AC motor, or a stepper motor. The motorized roller shutter 1 can include one or more batteries (not shown) configured to power the motor drive unit 7. Alternatively, or in addition, the motor drive unit 7 can be configured to connect to an electrical system in a building where the motorized roller shutter 1 is installed. For example, the roller shutter 1 can include an electrical cable configured to connect to the electrical system.The motor drive unit 7 may also include a wireless communication circuit, such as a radio frequency (RF) receiver or transceiver, to receive wireless signals (e.g., RF signals). The motor drive unit 7 may be configured to raise and lower the support bar 6 to control the amount of sunlight entering the space in response to a command received via wireless signals. Returning to FIG. 1B, a drive assembly 10 (also referred to herein as the motor drive unit) is shown, which may be arranged within a roll tube (not shown for simplicity of illustration, but which may be similar to roll tube 3 in FIG. 1A) for rotating the roll tube between various positions. The drive assembly 10 may include a housing 12 (also referred to herein as the motor drive unit housing). As illustrated, a portion (for example, here a top portion) of the housing 12 has been removed. The drive assembly 10 may include a drive motor 14 and a gear assembly 16. The housing 12 may retain the drive motor 14 and the gear assembly 16.The drive assembly 10, and therefore the drive motor 14, can be configured to receive power from a direct current (DC) and / or alternating current (AC) supply. Power can be supplied via cable (e.g., connected to a power outlet / source external to the motorized window treatment) or via a power outlet / source that is integral to the motorized window treatment. For example, the integral power source could be one or more batteries located inside the roller tube. Alternatively, the power outlet / source could be a photovoltaic power source, such as a solar panel. The drive assembly 10 may further include an electronic drive unit 18 configured to control the operation of the drive motor 14. For example, the electronic drive unit 18 may receive commands (for example, ultimately from a user who wishes to change the position of the flexible material) via a remote control unit or other external system controller, resulting in the operation of the drive motor 14. For example, the electronic drive unit 18 may receive a command that causes the electronic drive unit to control the operation of the drive motor 14 to cause movement in a rotational direction that results in the opening of the motorized window treatment.For example, the electronic drive unit 18 may receive a command that causes the electronic drive unit to control the operation of the drive motor 14 to cause movement in a rotational direction that results in the opening of the motorized window treatment. A printed circuit board 20 may be provided for mounting the control circuit (not shown) of the electronic drive unit 18. The drive assembly 10 may further include a bearing sleeve 22 and bearing mandrels 24 that are arranged at a first end of the housing 12 of the drive assembly 10 to engage an inner surface of a first end of the roller tube (not shown) and that allow the roller tube to rotate relative to the housing 12 of the drive assembly.The drive assembly 10 may further include a mechanism 25 for interconnecting or connecting the drive assembly housing 12 to a mounting support (not shown). As an example, the housing 12 may be fixed / non-rotating relative to the mounting support. The drive assembly 10 may further include a drive disc 26 disposed at a second end of the housing 12. The drive disc 26 may include features (such as longitudinal grooves) to promote engagement between an outer surface of the drive disc 26 and an inner surface of a second end of the roll tube (not shown) when the drive assembly 10 is received inside the roll tube. The drive disc 26 may be fixedly connected to a disc shaft 28 that is rotatably supported with respect to the housing 12 by a drive bearing 30. The disc shaft 28 may be operatively connected to the gear assembly 16 such that the actuation of the drive motor 14 rotates the gear assembly and thus the drive shaft and thus the drive disc 26.The drive disc 26, in turn, rotates the roll tube, thus winding and unwinding, for example, the flexible member in and out of the roll tube. The drive assembly 10 may further include a brake assembly 32, which may be arranged in the housing 12 and receives the shaft of the disc 28. Although a motorized window treatment can be balanced, for example, with countersprings to reduce the force required to roll up the flexible member, as can be seen, it is not always possible to perfectly balance the weight of the flexible member in all positions of the motorized window treatment. Consequently, even spring-balanced motorized window treatments may require a brake assembly to hold the flexible member in a selected position. As will be discussed, the brake assembly 32 is engaged when the motor is not in use. When the motor rotates a roller tube, for example, to a relatively closed or relatively open position of the blind, the brake assembly 32 is not engaged. The brake assembly 32 may include a brake inlet 34, a brake outlet 36, a brake spring 38, and a brake mandrel 40 (also referred to herein as the mandrel). A portion of the mandrel 40 projects into the drive disc 26 and is surrounded by the brake inlet 34, the brake outlet 36, and the brake spring 38. The mandrel 40 may be retained by the housing 12 and not rotate relative to the housing and may therefore also be referred to herein as the non-rotating mandrel. A gear cover 42 of the gear assembly 16 may be arranged adjacent to the brake mandrel 40. A motor adapter 44 may be positioned between the motor 14 and the gear cover 42 and may connect the motor output to the gear assembly 16.In operation, the disc shaft 28 can pass through the brake assembly 32, which can be adapted to engage the disc shaft to prevent relative rotation between the motor 14 and the drive disc 26 when the flexible member is not being wound / unwound (e.g., when the blind is not in use). It is understood that a load (e.g., a gravitational load) is applied to the roller tube due to the weight of an unwound portion of the flexible member (not shown) and an optional rod (if present). Engaging the brake assembly 32 counteracts this load and prevents the flexible member from unwinding (e.g., when the blind is not in use). With reference now to FIG. 1C, a brake spring 38 can be formed from wire (such as a single piece of wire) and can comprise a plurality of (for example, two or more) turns or coils 38a. Both the wire diameter and the number of turns can affect the brake's drag force. The brake spring 38 can terminate at each respective end in a bend 38b, thus creating a tongue 38c having a distal end 38d. The brake spring 38 can be arranged on the non-rotating mandrel 40. The brake spring 38 can have an inner or internal diameter 38e defined by the innermost surface of the plurality of turns 38a. When the spring is in a relaxed state, the diameter 38e can be slightly smaller than the non-rotating mandrel 40 (FIG. 1B). The brake inlet 34 and brake outlet 36 are rotatable and adapted to engage with at least one of the tabs 38c of the brake spring 38.When the brake input 34 rotates in any direction, the brake input pushes one or more of the tabs 38c, thereby relaxing the brake spring 38 (e.g., by increasing the inner diameter defined by the plurality of turns 38a). The brake spring 38 then slides over the non-rotating mandrel, allowing the brake output 36 to be driven by the brake input 34. In the absence of rotation of the brake input 34, gravity can cause a load / force on the flexible member, which, if uncontrolled, could result in the unwinding and subsequent lowering of the flexible member's position. In response, this load can cause the brake output 36 to push one or more of the tabs 38c, thereby retracting the brake spring 38. Retracting the brake spring 38 can cause a decrease in the inner diameter 38e defined by the plurality of turns 38a, and the brake spring 38 can grip tightly against the non-rotating mandrel 40, preventing rotation of the brake output 36 and, consequently, of the disc shaft 28. As a result, the brake assembly 32 can hold the flexible member in position. One problem with brake spring 38 is that the tabs 38c can, for example, bend as shown in curve 38b. Each of the tabs 38c is essentially a cantilever, taking all the force when brake spring 38 is actuated rearward. This can, for example, cause the tabs 38c to bend, resulting in the brake assembly slipping and the flexible member moving undesirably beyond its intended position. To compensate for and prevent the tabs 38c from bending, heavier spring wire can be used to form brake spring 38.However, a heavier cable can cause significant drag on the brake spring 38 (e.g., against the non-rotating mandrel) when the brake output is driven by the brake input 34. This is because it is more difficult for the brake input to relax the brake spring 38 (e.g., by increasing the inner diameter 38e defined by the plurality of turns 38a) and thus for the brake spring 38 to slide on the non-rotating mandrel. This drag can cause energy efficiency problems. For example, in the case of battery-operated blinds, when using a brake spring like the one in FIG. 10, the operating friction between the brake spring 38 and the non-rotating mandrel 40 can consume enough battery power to move the blind. Consequently, what is needed are improved brake assemblies for motorized curtains that employ, for example, motorized roller tube systems, including battery-operated blinds, improved brake springs for the same, and methods for reducing brake drag force in brake assemblies for motorized window treatments. Figure 2 illustrates a brake spring 46. The brake spring 46 may comprise wire formed into a plurality of coils 46a. The number of coils and the wire diameter may be determined based on the desired drag for a given application (for example, by using Equations 1 and 2 described herein to determine the desired performance). The plurality of coils 46a may terminate in a first turn 46b, a tongue 46c, a second bend 46d, a support portion 46e, and a tip 46f (46b-46f are collectively referred to as the tongue assembly). A variety of shapes are contemplated for tongue assemblies; for example, the tongue assemblies in Figure 2 and Figures 3-8 may be described as generally L-shaped. The first bend 46b is configured so that the tab 46c extends radially from the plurality of coils 46a, allowing interaction with an input member or an output member as will be described with reference to FIGS. 3-8. The brake spring 46 has an inner or inside diameter 46g. The inner or inside diameter 46g varies, depending on whether the brake spring 46 is in a relaxed or recoil state. As illustrated, the reed assemblies 46b-46f are mirror images of each other and have substantially the same geometries. The relative circumferential position of the reed assemblies is dictated by the length of wire (e.g., the number of turns) forming the brake spring 46. The second elbow 46d, the support portion 46e, and the tip 46f are arranged after the reed 46c. The support portion 46e holds the reed 46c when a force acts on the reed. The support portion 46e can be coupled to an input member (such as will be described as input member 62 or input member 92). The support portion 46e greatly reduces the danger of the reed 46c bending (or even breaking), for example, at the first bend 46b, because the stress is shared between the first bend and the support portion.Having the tongue 46c held by the support part 46e allows the use of a smaller wire diameter for the brake spring 46, which generates less drag when it rotates around the mandrel in an engaged state. Figures 3 and 4 depict a brake assembly 50 adapted for use in motorized window treatments, such as those associated with motorized roller tube systems. For example, the brake assembly 50 can be used within a drive assembly, such as in place of brake assembly 36 in drive assembly 10 of Figure 1B. For descriptive purposes only, drive assembly 10 (Figure 1B) may be used to illustrate the operation of the brake assembly 50. The engagement of the brake assembly 50 counteracts the gravitational load / force associated with the hanging portion of a flexible member and prevents the flexible member from unrolling when the window treatment is at rest (e.g., the motor is not being driven). The brake assembly 50 comprises a mandrel 52. The brake mandrel 52 may include a base 54, which may include features to aid attachment within a drive assembly, such as within a housing 12 of the drive assembly 10 (FIG. 1B). The base 54 of the brake assembly 50 may be fixedly attached to the housing 12 of the drive assembly 10 so that the brake mandrel 52 does not rotate relative to the housing. In this way, the brake mandrel 52 may also be referred to herein as a non-rotating mandrel. A body 56 may extend from the base 54. The body 56 may be annular in shape. The body 56 may have a distal portion 58. The distal portion 58 may also be one or more annular portions coaxial with the body 56. The distal portion 58 may comprise an outer surface 58a for receiving a brake spring 60 (the brake spring 60 may be substantially similar to the brake spring 46 of FIG. 2). The distal portion 58 may also define a bore 58b extending the entire length of the brake mandrel 52. A plurality of ribs 58c (three are shown in FIG. 4, although there may be fewer or more than three) may be arranged within the bore 58b. The ribs 58c can extend parallel to an axis defined by the hole 58b and can extend, for example, for at least a length equal to the length of the distal part 58. As another example, the plurality of ribs 58c can extend the entire length of the hole 58b (for example, a hole length represented by a brake mandrel length 52). A drive shaft (not shown in the FIG.3 and 4) passes through hole 58b, but cannot come into contact with the plurality of ribs 58c, allowing the drive shaft to rotate freely within the brake mandrel. The brake spring 60 may include a plurality of turns or coils 60a. The brake spring may be arranged around the mandrel 52, positioned on the surface 58a of the mandrel body 56. The brake spring 60 may have an inner diameter 38e defined by the innermost surface of the plurality of coils 60a. When in a relaxed state, the diameter 60g may be slightly smaller than the diameter 58d of the distal portion 58 of the body 56 (e.g., the diameter 58d may extend to the surface 58a). In a first rotational state, as will be described, the brake spring 60 may be tensioned (e.g., pulled back) and may be firmly engaged with the surface 58a of the distal portion 58, preventing relative rotation between the brake spring 60 and the brake mandrel 52.This, in turn, prevents the drive shaft, and therefore the coil tube, from rotating and thus the flexible member from unwinding, as if due to gravity, from the coil tube. Consequently, the first rotational state of the brake spring 60 can be a state of non-rotation with respect to the surface 58a of the mandrel 52. In a second rotational state, as will be described, the brake spring 60 can be forcibly relaxed (e.g., opened, thereby increasing the inner diameter 60g of the brake spring), allowing relative rotation between the brake spring 60 and the mandrel 52, although with some associated drag, since the diameter 60g can (e.g., still can) be slightly smaller than the diameter 58d of the distal part 58 of the body 56. In this second rotational state, the motor 14 of the drive assembly 10 can drive / rotate the shaft of the disc 28 and thus the disc assembly 26 and the roll tube, thereby driving the flexible member to a new position, so that the window treatment opens or closes further. Consequently, the second rotation state of the brake spring 60 can involve clockwise or counterclockwise rotation of the brake spring with respect to the surface 58a of the mandrel 52, and can be called the actuated state. The brake spring 60 may comprise wire formed in a plurality of coils 60a. A diameter (e.g., thickness) of the wire and a number of coils (e.g., turns) may be determined according to a desired application, e.g., using Equation 1 (drag to lower the shadow, e.g., at a constant speed) and Equation 2 (drag to raise the shadow): zwiznn / eznz / E / YiAi Τνι / =(ΕΗ4Δ[)2ΡΙ) *(β?πΝμ-1 ) / 32(D+h)4Equation 1 Τυ=(ΕΗ4Δϋ2ΡΙ)*(1-&ΖττΝ,ι) / 32(ϋ+ή)4Equation 2 where: E = Modulus of elasticity of the brake spring h = Diameter of the wire D = Mandrel outside diameter (OD) I = 1 / 4*ττ(ή / 2)4 Δ = Mandrel outer diameter (OD) - Spring inner diameter (ID) N = Number of turns μ = Coefficient of friction For example, referring to FIG. 4, the outer diameter of the mandrel (OD) can be the diameter between the two outermost points of surface 58a (e.g., diameter 58d). For example, the inner diameter of the spring can refer to the diameter 60g defined between the innermost surfaces of the plurality of coils 60a. The coefficient of friction can be between the mandrel material and the wire material. The plurality of coils 60a may terminate in a first radial bend 60b. As shown, the first bend 60a may be a perpendicular or 90-degree bend, but as will be seen, the first bend may be a gradual bend or a series of bends. A tab 60c may extend from the first bend 60b. A second bend 60d may be arranged at one end of the tab 60c, for example, after the tab. The second bend 60d may be opposite the first bend 60b. As shown, the second bend 60d may be a perpendicular or 90-degree bend, but as will be seen, the second bend may be a gradual bend or a series of bends. A support portion 60e may be arranged after the second bend 60d, the support portion terminating in a point 60f (see FIG. 3) which is the distal end of the brake spring 60. The support portion 60e can support the tongue 60c when a force acts on the tongue. The force may act on a portion of the tongue 60c or substantially on the entire tongue. Examples of forces acting on the tongue 60c may include a first force applied to pull back the plurality of coils 60a, causing the spring diameter 60g to contract and the coils to engage with the mandrel surface 58a, and a second force applied to relax the plurality of coils, thereby causing the spring diameter 60g to expand and the coils to slide relative to the mandrel surface 58a. As discussed with reference to brake spring 38 in FIG. 1C, the tabs (e.g., tabs 38c) acted as cantilevers and were susceptible to bending, for example, at the bend (e.g., bend 38b) formed by the tab. A bent tab can cause a flexible member to slowly uncoil to a fully closed position, for example, after being placed in a position that might annoy consumers. The support portion 60e greatly reduces the forces on tab 60c and thus prevents tab 60c from bending, for example, at the first bend 60b, because the stress is shared between the first bend and the support portion 60e. In addition, having the tongue 60c held by the support portion 60e may allow the use of a smaller wire diameter for the brake spring 60, which may create less drag when the spring 60 rotates around the mandrel in the actuated state.Less drag requires less effort from a motor, which can improve battery life, which is a consideration / advantage for battery-powered blinds. The first bend 60b, the tongue 60c, the second elbow 60d, the support portion 60e, and the tip 60f may be collectively referred to as the tongue assembly. However, in Figures 3 and 4, it is understood that there may be a substantially similar arrangement at the other end of the plurality of coils 60a (see, for example, Figure 2). In some embodiments, the tongue assemblies may be mirror images of each other (e.g., the other points in the opposite direction; for example, if one tongue assembly points clockwise when viewed from the end (e.g., along an axis defined by the distal portion of the mandrel 58), the other tongue assembly points counterclockwise). In some embodiments, the geometry of each of the tongue assemblies is different.The relative circumferential position of the tongue assemblies is dictated by the length of wire (e.g., the number of turns) that make up the brake spring 60. The brake assembly 50 may further comprise an input member 62. The input member 62 may comprise an annular base 64 defining a bore 64a. A coupler 66 may be arranged in the bore 64a. The coupler 66 may define a bore 66a adapted to engage a drive shaft (not shown in Figures 3 and 4) for rotating the input member 62 about an axis coaxial with the bore 66a. In a first direction of rotation of the drive shaft, and therefore of the input member 62, motion is imparted to a disc (for example, the drive disc 26 in Figure 1B) that engages with the roll tube such that the flexible member is wound around the roll tube and raised.In the opposite direction of rotation of the drive shaft and, therefore, input member 62, the flexible member unwinds from the coil tubes and the drive shaft and thus descends. For clarity, in both directions of rotation of the input member 62, the brake spring 60 is in the engaged state, as will be described. The bore 66a may have features (e.g., splines) for mating with the drive shaft, although other mechanisms may be used. A body 68 may extend from the base 64 of the input member 62 in the direction of the brake spring 60 and the mandrel 52. The body 68 may be annular in shape. The body 68 may have a first surface 68a. A coupling surface 68b may be provided on the body 68 to couple a portion of an output member 70, the coupling surface being perpendicular to surface 68a. A side wall 68c may extend from the body 68 in the direction of the brake spring 60 and the mandrel 52. A recessed surface 68d may be adjacent to the side wall 68c and be recessed or stepped relative to the side wall 68c. The recessed surface 68d may receive a portion of the brake spring 60, such as the support portion 60e and the tip 60f.The recessed surface 68d can support the support part 60e and the tip 60f of the brake spring 60, thus reducing the stress on the first bend 60b imparted by a force acting on the tongue 60c. An edge 68e of the body 68 may be adjacent to the recessed surface 68d to engage a portion of the brake spring 60, such as the tongue 60c, when the brake assembly 50 is in the second rotational state. The input member 62 may be symmetrical; for example, it may have similar features arranged on the other side of the brake assembly 50 to engage with the other tongue assembly. As an example, when the motor of the motorized window treatment is activated to raise or lower the flexible element, the drive shaft can rotate the input member 62. The rotation of the input member 62 can cause the rim 68e to apply a force to the tab 60c, driving the brake spring 60, which causes the brake spring to expand and disengage (or at least slide relative to) the surface 58a of the mandrel 52 (e.g., progressively larger diameter 60g), and allow the drive shaft (and therefore the disc, and therefore the roller tube and the flexible material) to rotate freely relative to the mandrel. The stress experienced by the first bend 60b of the brake spring 60 due to the force applied to the tab 60c can be partially offset by the support portion 60e that engages with the recessed surface 68d of the input member 62. The brake assembly 50 further comprises an output member 70. In some embodiments, unlike the spring 60 and the input member 62, the output member 70 may not be symmetrical. However, it may be advantageous to have a symmetrical output member 70, for example, for universal compatibility with right-handed or left-handed curtain configurations. zwiznn / eznz / E / YiAi The output member 70 comprises an annular base 72 defining a bore 72a. The bore 72a is adapted to receive a disc shaft (not shown in FIG. 3 and 4) that is coupled to a disc (e.g., such as the drive disc 26 in FIG. 1B) that is coupled to the roll tube. A plurality of ribs 74 may extend radially from the base 72. Several of the plurality of ribs 74 also extend axially in the direction of the input member 62, the brake spring 60, and the mandrel 52. The plurality of ribs 74 need not be identical; for example, the plurality of ribs may not all have the same length. A mating surface 74a can be provided on one of the plurality of ribs 74 to engage the tongue 60c of the brake spring 60 when the brake assembly 50 is in the first rotational state. For example, the input and output members can be engaged on opposite sides of the tongue 60c.For example, when the motor of the motorized window treatment is not engaged, a gravitational load is applied to the roller tube due to the weight of an unrolled (e.g., hanging) portion of the flexible member. This load is transferred to the disc, and from there to the output member 70 via the disc shaft. Rotation of the output member 70 causes the coupling surface 74a to apply a force to the tongue 60c, driving the brake spring 60 backward. This causes the brake spring to engage with surface 58a of the mandrel 52 (e.g., diameter 60g to become smaller), stopping the rotation of the brake spring, the output member, and the disc, and thus preventing the flexible member from unrolling. The tension experienced by the first bend 60b of the brake spring 60 due to the force applied to the tongue 60c is partially compensated by the support portion 60e that engages with the recessed surface 68d of the input member 62.A body 76 extends from the base 72 of the output member 70 in the direction of the input member 62, the brake spring 60, and the mandrel 52. One or more of the plurality of ribs 74 are also attached to the body 76. A side wall 76a extends axially from the body 76 in the direction of the input member 62, the brake spring 60, and the mandrel 52. The side wall 76a may be arranged between a portion of the plurality of ribs 74. A mating surface 76b may be arranged on the body 76, for example, on one side of a rib distal to the side wall 76a, to mate the mating surface 68b of the input member 62.When driven by the motor in a first direction of rotation, the input member 62 rotates (clockwise, as illustrated), causing the coupling surface 68b to come into contact with the coupling surface 76b and the output member 70 to rotate, with the disk shaft imparting the rotation of the output member to the disk, thereby winding or unwinding the flexible member depending on the direction of rotation of the motor. As shown in FIG. 3, the side wall 68c and the recessed surface 68d of the input member 62 cover a portion of the coil plurality 60a, a portion of the mandrel body 56, and the distal portion 58. The support portion 60e and the tip 60f of the brake spring 60 are engaged with the recessed surface 68d. The side wall 76a of the output member 70 covers another part of the plurality of coils 60a, a part of the body 56 and the distal part 58 of the mandrel 52, and the base 64 and surface 68a of the input member 62. Because the side wall 68c and the recessed surface 68d of the input member 62 and the side wall 76a of the output member 70 cover most of the plurality of coils 60a, only a part of the tab 60c, the second bend 60d, the support part 60e, and the tip 60f of the brake spring 60 are visible in FIG. 3. In operation, as will be explained, the brake assembly 50 engages when a motor is not in use. When the motor rotates a roller tube, for example, to a relatively closed or relatively open position of the window treatment, the brake assembly 50 does not engage. Although some drag is associated with the brake assembly 50, it is less than a conventional amount, such as that which might be experienced with a spring in FIG. 1C, for example (due, for instance, to the smaller diameter wire that springs with the described support portions can use), and therefore requires less energy to overcome. The brake assembly 50 can be particularly useful for battery-operated window treatments, such as battery-operated blinds, including motorized window treatments with a balanced spring (e.g., battery-operated blinds with a balanced spring).The 50 brake assembly may be associated with longer battery life for battery-powered window treatments. In the first state of rotation, the brake spring 60 is tensioned by the action of gravity acting on the flexible member, the coupling surface 74a of the output member 70 applies a force to the tongue 60c, pushing back the brake spring and causing the brake spring to engage the surface 58a of the mandrel 52, stopping the rotation of the brake spring, the output member and the disc, and thus preventing the flexible member from unwinding.In the second rotation state, a motor acts on the drive shaft (e.g., clockwise or counterclockwise), rotating the input member 62. This causes the rim 68e to exert a force on the tongue 60c of the brake spring 60, thereby relaxing the brake spring and allowing the brake spring, the output member 70 (via the mating surface 68b that contacts the mating surface 76b), and the disc to rotate. Consequently, the motor can drive the flexible member to a new position, so that the window treatment (e.g., flexible material) opens or closes further. Figures 5 and 6 depict a brake assembly 80 in the first rotational state, which can also be referred to as the locked state. The brake assembly 80 can be an example of the brake assembly 50 depicted in Figures 3 and 4. The brake assembly 80 can be installed at either end of a roller tube. For example, there are curtain configurations for right-handed or left-handed users (with reference to the arrangement of the brake assembly 80 on the roller tubes). A symmetrical design will be inefficient, since if it is installed at the right end of a roller tube, for example, a different set of latches will act as the lock than if the brake assembly is installed at the left end, where the other set of latches would act as the lock. The brake assembly 80 comprises a mandrel 82. The mandrel 82 includes a base 84 and a body 86 extending from the base 84. The body 86 may have a distal portion 88 comprising an outer surface 88a for receiving a brake spring 90. The distal portion 88 defines a bore 88d. A plurality of ribs 88c may be arranged within the bore 88d (three ribs are shown in FIG. 6) and extend parallel to an axis defined by the bore. A brake spring 90 is positioned on surface 88a of the distal portion 88 of the mandrel 82. In the first rotational state (represented), the brake spring 90 is tensioned and tightly coupled to surface 88a, preventing relative rotation between the brake spring 90 and the mandrel 82. The brake spring 90 may comprise wire formed into a plurality of coils 90a. The number of coils and the wire diameter may be determined based on the window treatment application (for example, by using Equations 1 and 2 described herein to determine the desired performance).The plurality of coils 90a can terminate in a pair of reed assemblies, a first reed assembly comprising a first bend 90b, a reed 90c, a second bend 90d, a support portion 90e, and a tip 90f, and a second reed assembly comprising a first bend 90'b, a reed 90'c, a second bend 90'd, a support portion 90'e, and a tip 90'f. As illustrated, the reed assemblies are mirror images of each other and have substantially the same geometries. The relative circumferential position of the reed assemblies is dictated by the length of wire (e.g., the number of turns) forming the brake spring 90. Any description relating to 90b-90'f may also apply to 90'a-90'f, but only the former are discussed below for ease of explanation. It is observed that the second bend 90d, the support portion 90e, and the tip 90f are positioned after the tab 90c. The support portion 90e holds the tab 90c when a force is applied to it. The support portion 90e greatly reduces the deflection of the tab 90c, for example, at the first bend 90b, because the stress is shared between the first bend and the support portion. According to another example, having the tab 90c held by the support portion 90e allows the use of a smaller wire diameter for the brake spring 90, which creates less resistance when it rotates around the mandrel in an actuated state. Less drag requires less effort from a motor, improving battery life—a very important consideration for battery-operated window treatments. The brake assembly 80 further comprises an input member 92. The input member 92 defines a bore (not visible) that retains a coupler 96, which defines a bore 96a adapted to engage with a drive shaft (not shown). The drive shaft is adapted to be driven by the motor to rotate the input member 92; however, in the first rotational state shown, the motor is not driven. The input member 92 comprises a body 98 having a side wall 98c. A recessed surface 98d is adjacent to the side wall 98c and extends down from it to receive the support portion 90e and the tip 90f of the brake spring 90. An edge 98e of the body 98 is adjacent to the recessed surface 98d to engage a portion of the brake spring 90, such as the tab 90c, when the brake assembly 80 is in a second rotational state (FIG. 8).As illustrated, the input member 92 is symmetrical and therefore has a recessed surface 98'd and an edge 98'e, for example, to accommodate the second tongue assembly comprising the first bend 90'b, the tongue 90'c, the second bend 90'd, the support part 90'e and the tip 90'f. The brake assembly 80 further comprises an output member 100. The output member 100 comprises an annular base 102 defining a bore (not visible in FIGS. 5 and 6) adapted to receive a drive shaft (not shown) that can be coupled to a disc (such as the drive disc 26) fitting into the roll tube (not shown). A plurality of ribs 104 can extend radially from the base 102. Several of the plurality of ribs 104 also extend axially in the direction of the input member 92, the brake spring 90, and the mandrel 82. A mating surface 104a can be arranged on one of the plurality of ribs 104 to engage the tongue 90c of the brake spring 90 when the brake assembly 80 is in the first rotational state (FIG. 6). A body 106 extends from the base 102 in the direction of the input member 92, the brake spring 90, and the mandrel 82. The plurality of ribs 104 are also attached to the body 106. A side wall 106a extends axially from the body 106 in the direction of the input member 92, the brake spring 90, and the mandrel 82. The side wall 106a can be arranged between a portion of the plurality of ribs 104. A mating surface 106b can be arranged on the body 106 to engage a mating surface 98b (FIG. 5) of body 98 of the input member 92. In operation, a gravitational load is applied to the coil tube due to the weight of an uncoiled (e.g., hanging) portion of the flexible member. This load is transferred to the disc, and from there to the output member 100 via a drive shaft, such as the disc shaft 28 (FIG. 1B). Rotation of the output member 100 causes the mating surface 104a to apply a force to the tongue 90c, driving the brake spring 90 backward. This causes the plurality of coils 90a to engage with the surface 88a of the mandrel 82, stopping the rotation of the brake spring, the output member, and the disc, and thus preventing the flexible member from uncoiling. The tension zwiznn / eznz / E / YiAi experienced by the first bend 90b of the brake spring 90 due to the force applied to the tongue 90c can be partially compensated by the support part 90e that engages with the recessed surface 98d of the input member 92.The support portion 90e greatly reduces the forces on the tongue 90c and thus prevents the tongue 90c from bending, for example, at the first bend 90b, because the stress is shared between the first bend and the support portion. The support portion 90e can slide along the recessed surface 98d. Figures 7 and 8 illustrate the brake assembly 80, as described above and using the same part numbers, in the second rotational state, which may also be referred to as the driven state. The motor has driven the drive shaft to rotate the input member 92 (e.g., clockwise in Figure 8). This causes the edge 98e of the input member 92 to exert a force on the tab 90c of the brake spring 90, thereby relaxing the brake spring (e.g., the inner diameter of the plurality of coils 90a increases in response to the force). The plurality of coils 90a slides relative to the surface 88a of the mandrel 82, and allows rotation of the brake spring 90, the output member 100, and the disc (not shown). Consequently, the motor can drive the flexible member to a new position, so that the window treatment opens or closes further.The recessed surface 98d supports the support part 90e of the brake spring 90, reducing the stress exerted on the first bend 90b by the force acting on the tongue 90c. Figure 9A illustrates a brake spring 110 according to another embodiment, which can be used in a brake assembly similar to those described herein. The brake spring 110 can comprise wire formed into a plurality of coils 110a. The number of coils and the wire diameter can be determined based on the window treatment application (for example, by using Equations 1 and 2 described herein to determine the desired performance). The plurality of coils 110a can terminate in a pair of reed assemblies, where each reed assembly comprises a first bend 110b, a reed 110c, and a second bend 110d. The second bend 110b is configured such that the reed 110c extends radially from the plurality of coils 110a. In this embodiment, the reed 110c can only interact with one output member. A support part 110e and a tip 110f are arranged after the second bend 110d.The support portion 110e comprises two straight portions divided by a curve. The portion of the support portion 110e that is radial to the plurality of coils 110a (e.g., the portion parallel to the tongue 110c) can be coupled, e.g., only coupled, to an input member (as in the edge 98e of the input member 92 in FIG. 8). The tip 110f can be coupled to an input member having a feature similar to the recessed portion (as in the recessed portion 98e of the input member 92 in FIG. 8) or, preferably, can be coupled directly to a mandrel (as in the surface 58a of the distal portion 58 of the mandrel 52 (FIG. 3)). The brake spring 110 can have an inner or internal diameter 110g defined by the innermost surface of the plurality of coils 110a.When in a relaxed state, the diameter 110g may be slightly smaller than the diameter of a mandrel to which it is coupled (e.g., as surface 58a of the distal part 58 of the mandrel52 (FIG. 3)). As illustrated, the reed assemblies 46b-46f are mirror images of each other and have substantially the same geometries. The relative circumferential position of the reed assemblies is dictated by the length of wire (e.g., the number of turns) forming the brake spring 110. The second bend 110d, the support portion 110e, and the tip 110f are arranged after the reed 110c. The support portion 110e and the tip 110f support the reed 110c when a first force acts on the reed, e.g., a locking force applied by an output member (as in FIG. 6). The first bend 110b supports the support portion 110e when a second force acts on the support portion, e.g., a driving force applied by an input member (as in FIG. 8).The stress resulting from a force (e.g., affecting the plurality of coils 110a) acting on a radial member (e.g., the tongue 110c or the support portion 110e) is reduced because the stress is shared between two points. For example, the stress is shared between the first bend 110b and the tip 110f. Having two support points allows the use of a smaller wire diameter for the brake spring 110, which generates less resistance when it rotates around the mandrel in an actuated state. The tongue assembly of FIG. 9A can be described as generally U-shaped. Figure 9B illustrates a brake spring 120 according to another embodiment, which can be used in a brake assembly similar to those described herein. The brake spring 120 can comprise wire formed into a plurality of coils 120a. The number of coils and the wire diameter can be determined based on the window treatment application (for example, by using Equations 1 and 2 described herein to determine the desired performance). The plurality of coils 120a can terminate in a pair of reed assemblies, where each reed assembly comprises a first bend 120b, a reed 120c, and a second bend 120d. The second bend 120b is configured such that the reed 120c extends radially from the plurality of coils 120a. In this embodiment, the reed 120c can only interact with one output member. A support part 120e and a tip 120f are arranged after the second bend 120d.The support portion 120e comprises three straight portions divided by a pair of curves. The portion of the support portion 120e that is radial to the plurality of coils 120a (e.g., the portion parallel to the tongue 120c) can be coupled, e.g., only coupled, to an input member (as at the edge 98e of the input member 92 in FIG. 8). The portion of the support portion 120e that is adjacent to the plurality of coils 120a can be coupled to an input member having a feature similar to the recessed portion (as at the recessed portion 98e of the input member 92 in FIG. 8) or can be coupled directly to a mandrel (such as the surface 58a of the distal portion 58 of the mandrel 52 (FIG. 3)). The 130f tip can be attached to an inlet member that has a feature similar to the recessed part.The brake spring 120 can have an inner or internal diameter 120g defined by the innermost surface of the plurality of coils 120a. When in a relaxed state, the diameter 120g can be slightly smaller than the diameter of a mandrel to which it is coupled (e.g., as surface 58a of the distal part 58 of the mandrel 52 (FIG. 3)). As illustrated, the reed assemblies are mirror images of each other and have substantially the same geometries. The relative circumferential position of the reed assemblies is dictated by the length of wire (e.g., the number of turns) forming the brake spring 120. The second bend 120d, the support portion 120e, and the tip 120f are arranged after the reed 120c. The support portion 120e holds the reed 120c when a first force acts on the reed, e.g., a locking force. The first bend 120b supports the support portion 120e when a second force acts on the radial portion of the support portion, e.g., a driving force. The stress incident to a force (e.g., to affect the plurality of coils 120a) acting on a radial member (e.g., the tongue 120c or the support part 120e) is reduced because the stress is shared between two points.For example, the tension is shared between the first bend 120b and the support portion 120e, which is adjacent to the plurality of coils 120a. Having two support points allows the use of a smaller wire diameter for the brake spring 120, which generates less resistance when it rotates around the mandrel in an actuated state. The tongue assembly of FIG. 9A can be described as generally U-shaped. Figure 9C illustrates a plan view of a brake spring 130 according to another embodiment, which may be used in a brake assembly similar to those described herein. The brake spring 130 may comprise wire formed into a plurality of coils 130a. The number of coils and the wire diameter may be determined based on the window treatment application (for example, by using Equations 1 and 2 described herein to determine the desired performance). The plurality of coils 130a may terminate in a pair of tongue assemblies, where each tongue assembly comprises a first bend 130b, a tongue 130c, and a second bend 130d. In this embodiment, the tongue portion 130c may be loop-shaped. The tongue portion 130c may engage an outlet member on a first side and an inlet member on a second (e.g., opposite) side.A support portion 130e and a tip 130f are arranged after the second bend 130d. The support portion 130e can be coupled to a mandrel (e.g., the same surface of a mandrel that can be coupled to the plurality of coils). The brake spring 130 can have an inner diameter 130g defined by the innermost surface of the plurality of coils 130a. When in a relaxed state, the diameter 130g can be slightly smaller than the diameter of a mandrel to which it is coupled (e.g., as surface 58a of the distal portion 58 of the mandrel 52 (FIG. 3)). As illustrated, the reed assemblies are mirror images of each other and have substantially the same geometries. The relative circumferential position of the reed assemblies is dictated by the wire length (e.g., the number of turns) forming the brake spring 130. The second bend 130d, the support portion 130e, and the tip 130f are arranged after the reed 130c. The support portion 130e holds the reed 130c when a first force, e.g., a locking force, or a second force, e.g., a driving force, acts on the reed. The stress incident to a force (e.g., to affect the plurality of coils 130a) acting on the reed 130c is reduced because the stress is shared between two points. For example, the tension is shared between the first bend 130b and the support portion 130e.Having two support points allows the use of a smaller wire diameter for the 130 brake spring, which generates less resistance when it rotates around the mandrel in an actuated state. The tongue assembly of FIG. 9C can be described as generally U-shaped. The foregoing detailed description has been disclosed with reference to specific embodiments. However, the description is not intended to be exhaustive nor limited to the exact embodiment described. Those skilled in the art will appreciate that changes can be made to the embodiments described above without departing from the broad inventive concept therein. Therefore, this disclosure is intended to cover modifications within the spirit and scope of disclosure as defined in the appended claims.

Claims

1. A brake assembly for a window treatment comprising a motorized roll-up tube system, wherein the brake assembly comprises: a mandrel; and a brake spring disposed on the mandrel, the brake spring comprising a plurality of coils and a tongue extending from the plurality of coils, the tongue having a first bend at a first end of the tongue adjacent to the plurality of coils and a second bend at a second end of the tongue, wherein a support portion extends from the second bend.

2. The brake assembly of claim 1, wherein, in a first rotational position, a force is exerted on the tongue, thereby pushing the spring backward, causing the plurality of coils to squeeze the mandrel and prevent rotation between them.

3. The brake assembly of claim 2, further comprising an output member, wherein the force is a gravitational force.

4. The brake assembly of claim 2, wherein, in a second rotational position, a second force is exerted on the tongue to overcome the first force, thereby causing the plurality of coils to loosen in the mandrel and allow rotation between them.

5. The brake assembly of claim 4, further comprising an input member, wherein the second force is a driving force from a motor.

6. The brake assembly of claim 5, wherein the support portion engages with the input member in both the first rotation position and the second rotation position.

7. The brake assembly of claim 2, further comprising a second tab extending from the plurality of coils at a distal end of the plurality of coils and a second support part extending from the second tab.

8. The brake assembly of claim 7, wherein, in a second rotational position, a second force is exerted on the tongue to overcome the first force, thereby causing the plurality of coils to loosen in the mandrel and allow rotation between them.

9. A brake spring for a motorized coiled tube system, wherein the brake spring comprises: a plurality of coils having a tongue assembly at each end, wherein each tongue assembly comprises a radially extending tongue and a support portion extending from the tongue to reduce tension on the tongue.

10. The brake spring of claim 9, wherein the tongue is supported at two points from the incident tension to a force applied to the tongue.

11. The brake spring of claim 9, wherein each tongue assembly further comprises a first curvature extending between the plurality of coils and the tongue and a second curvature extending between the tongue and the support portion.

12. The brake spring of claim 9, wherein the tongue assembly is L-shaped, U-shaped, Ω-shaped, or O-shaped.

13. A window treatment, comprising: a roll-up tube for winding a flexible member; and a drive assembly disposed on the roll-up tube, wherein the drive assembly comprises a motor, an electronic drive unit, a drive shaft for rotating a disc connected to the roll-up tube via a disc shaft, and a brake assembly; wherein the brake assembly comprises: a mandrel; an input member coupled to the drive shaft and rotating about the mandrel; an output member coupled to the drive shaft and rotating about the mandrel; a brake spring disposed on the mandrel, wherein the brake spring comprises: a plurality of coils; a tab extending from the plurality of coils; and a support portion extending from the tab for reducing tension on the tab; wherein, when the motor is not driven, the brake assembly prevents the flexible member from unwinding.

14. The window treatment of claim 13, wherein the motor is battery operated.

15. The window treatment of claim 13, when the motor is not driven, exerts a force on the tongue, thereby driving the spring backward, causing the plurality of coils to squeeze the mandrel and prevent rotation between them.

16. The window treatment of claim 15, wherein the force is a gravitational force exerted by a hanging portion of the flexible member.

17. The window treatment of claim 15, wherein, in a second rotational position, a second force is exerted on the tongue to overcome the first force, thereby causing the plurality of coils to loosen in the mandrel and allow rotation between them.

18. The window treatment of claim 17, wherein the second force is a driving force.

19. The window treatment of claim 17, wherein the support portion engages with the input member in both the first rotation position and the second rotation position.

20. The window treatment of claim 13, further comprising a second tab extending from the plurality of coils at a distal end of the plurality of coils and a second support portion extending from the second tab. zfrnznn / eznz / E / YiAi 21. The window treatment of claim 20, wherein the motor drive exerts a force on the second tab, thereby causing the plurality of coils to loosen in the mandrel and allow rotation between them, permitting the flexible member to unwind from the roll tube.

Images