ANTI-VIBRATION BRACKET FOR TUBULAR MOTOR
FIELD OF THE INVENTION
The present invention relates generally to motorized window coverings.
BACKGROUND OF THE INVENTION
Several systems for either lowering or raising a window covering, or for moving the slats of a window covering between open and closed positions, under control of a hand-held remote or other control device are known. These systems include a motor that is coupled through gears to the window covering activation mechanism. When the motor is energized in response to a user command signal, the activation mechanism moves the window covering.
As recognized herein, it is desirable to minimize the noise emitted by such systems during operations. As further recognized herein, most of the noise is due to vibrations of the head rail and/or tube in which the tubular motor is disposed, caused by vibrations of the motor. The present invention understands that these vibrations are transmitted to the surface (such as a dwelling wall) supporting the assembly because the assembly typically is held to the wall by rigid or at least non-flexible brackets.
As understood herein, other bracket systems have attempted to dampen the transmission of vibrations from the motor to the mounting surface by applying rubber, silicone, urethane or other soft materials between the rigid bracket and the mounting surface. One solution that has been advanced is to make the entire bracket out of a rubber material, but the present invention critically recognizes that this device is limited by the torque of the system. Furthermore, during attachment of the bracket to the mounting surface, the soft material is compressed together, resulting
in the relatively rigid connection sought to be avoided in the first place and limiting the freedom of movement of the system. With this in mind, the present invention recognizes the desirability of dampening noise without unduly limiting the torque of the system, i.e., to provide a noise dampening system that is substantially torque independent.
SUMMARY OF THE INVENTION
An electrical power-drive device includes a tubular motor assembly including a rotatable tube holding a motor therein. A motor bracket couples the tubular motor assembly to a fixture. The motor bracket includes a rigid member that can be fastened to the fixture, and plural flexible elements depending downwardly from the rigid member. The flexible elements are coupled to the tubular motor assembly to couple the tubular motor assembly to the fixture while attenuating propagation of vibrations from the tubular motor assembly to the fixture. These flexible elements are arranged in such a way that the horizontal stiffness is low compared to the vertical stiffness.
The flexible elements may be arranged in such a way that they work in tension or in compression.
In non-limiting embodiments the flexible elements may be flexible rubber, urethane, silicone, air or fluid filled rubber, fabric, rope or plastic strings or they may be metal wires having motion in at least two degrees of freedom.
Several embodiments of the electrical power-drive device according to the invention are defined by dependent Claims 2 to 12.
A powered assembly according to the invention is defined by Claim 13.
Several embodiments of the powered assembly according to the invention are defined by dependent Claims 14 to 24.
The details of the present invention, both as to its construction and operation, can best be understood in reference to the accompanying drawings, in which like numerals refer to like parts, and which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a partial cross-sectional view of the present tubular motor assembly for moving an object such as but not limited to a window covering, awning, projector screen, and the like, showing the idler bracket and motor bracket connecting the tubular motor assembly to a mounting surface;
Figure 2 is a schematic end view and front view of a first variant of the first embodiment of the anti-vibration bracket that can be used as the motor bracket in Figure 1 , showing coiled wire rope in tension suspending the motor;
Figure 3 is a schematic end view and front view of a first variant of the second embodiment of the anti-vibration bracket that can be used as the motor bracket in Figure 1 , showing coiled wire rope in compression supporting the motor;
Figure 4 is a schematic end view of a second variant of the first embodiment of the anti-vibration bracket that can be used as the motor bracket in Figure 1 , showing flexible strings in tension suspended through respective bracket channels to hold the motor, in a no-torque configuration;
Figure 5 is a schematic end view of the second variant of the first embodiment of the anti-vibration bracket, shown in a configuration wherein the window covering is extended, producing a torque;
Figure 6 is a schematic end view of a second variant of the second embodiment of the anti-vibration bracket that can be used as the motor bracket in Figure 1 , showing springs in compression suspending the motor;
Figure 7 is a schematic end view of a third variant of the first embodiment of the anti-vibration bracket that can be used as the motor bracket in Figure 1 , showing strings in tension suspending the motor;
Figure 8 is a schematic end view of a fourth variant of the first embodiment, showing a tape in tension suspending the motor; and
Figure 9 is a schematic end view of a fifth variant of the first embodiment, showing two crossed wires in tension suspending the motor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring initially to Figure 1 , a motorized covering is shown, generally designated 10, that includes a rotating tube 12 suspended from which or around which may be wrapped a movable object 14, such as but not limited to a shade assembly that is raisable (by rolling up) and lowerable (by rolling down, or unrolling). The rotating tube 12 rotates by means of an electrical actuator 20, which preferably is mainly included in the tube. In that case, a tubular actuator is used.
The rotating tube 12, the reliable object 14 and the electrical actuator 20 constitute a suspended mass 11 , being a subset of the window covering,
which is suspended by means of two brackets that will be more described more in detail hereunder.
"Tubular motor assembly" will often designate hereunder this suspended mass 11.
While a roll-up shade is shown, it is to be understood that the principles herein apply to a wide range of window coverings and other objects that are to be moved by motors. For example, the invention applies to raisable and lowerable pleated shades and cellular shades such as those commonly marketed under the trade names "Silhouette", "Shangri-La", etc. as well as to projector screens, security screens, awnings, roller doors, roller art work, etc. that can be moved by tilting and/or by raising and lowering. Thus, for example, the rotating tube 12 may be a steel or aluminum roll-up rod or tube of a shade, awning, or projector screen, or a tilt rod of a horizontal (or vertical) blind, or other like operator. It is thus to be further understood that the principles of the present invention apply to a wide range of window coverings and other objects including, but not limited to the following: vertical blinds, fold-up pleated shades, roll-up shades, cellular shades, skylight covers, etc. Powered versions of such shades are disclosed in U.S. Patent No. 6,433,498, incorporated herein by reference.
Figure 1 shows that the electrical actuator 20 can include an AC induction motor 21 , as a single-phase squirrel-cage rotor motor, which is coupled to a planetary gear train 23. A brake 22 may be coupled between the electric motor and the gear train to stop the motor when de-energized.
When the motor 21 is energized, its rotor turns, which turns the gear train
23 that in turn rotates the output shaft 24, which is coupled to an adapter 29. The adapter 29 is engaged with the inside of the tube 12 so that when the adapter turns, the tube 12 turns and, hence, the movable object
14, which is attached to the tube 12, moves, either by raising or lowering or tilting. The head 26 of the motor housing is held from turning by the below-described motor bracket.
To create the appropriate lag in phase between the windings of the induction motor, a preferably small, lightweight capacitor 25 may be connected to the induction motor 21. To power the actuator 12, standard power from the public AC power grid 16 may be used. The tubular actuator may be realized as disclosed in US patents No. 5,105,871 - 5,220,721 - 5,429,558 - 4,720,647, incorporated herein by reference.
Alternatively, the electric motor 21 may be a DC motor and the capacitor 25 is then replaced by a simple rectifier or replaced by an AC-DC bulk converter if the DC motor is of a low voltage type.
It is to be understood that the power supply may be implemented by means of batteries of rechargeable type or of the dry type as AA or AAA lithium or alkaline batteries. The batteries may be located inside or outside the tube 12.
Figure 1 also shows that the motorized covering 10 can include an externally wired IR or RF control signal generator 15 or an internal RF receiver with electronic control board limit switch unit 27 included in the actuator 20, for receiving a user command IR or RF signal. Preferably, the user command signal is generated by a hand-held user command signal generator 18, which can be an infrared (IR) remote-control unit or a radio frequency (RF) remote-control unit, equipped with a user interface as a keypad 19. Or the user command signal may be generated by any other means of communication well known in the art, such as by
manipulable manual switches 17. The user command signals can include open, close, raise, lower, intermediate position and so on.
The electronic limit circuit board 27 can be electronic or a mechanical counting limit switch unit which both are disposed inside the actuator 12. The preferred electronic circuit board 27 includes a microprocessor and/or logic chip for processing the control signals from the transmitter 18.
In accordance with present principles, the suspended mass 11, which can be established by a tubular motor assembly in accordance with the disclosure above, is mounted on a mounting surface 30 by means of at least one and preferably two noise dampening brackets that can be identical to each other in configuration and operation. One bracket is an idler bracket 32 and engages with the idler end cap 13, while the opposite bracket is a motor bracket 31. The motor bracket 31 is engaged with the actuator head 26 that is fixedly engaged with the housing of the actuator 20 to take up, like the idler bracket 32, one-half of the static load of the actuator 20, of the tube 12 with movable object 14, and also, unlike the idler bracket 32, to absorb substantially all of the dynamic load induced by motor torque and/or the static torque when the window covering is fully extended. A bearing 28 allows the rotation of the tube 12 relatively to the fixed housing of the actuator 20. It is to be understood that the mounting surface 30 may be a wall, window jamb, head rail of a window covering, or other fixture.
Now referring to a non-limiting illustrative embodiment in Figure 2, one exemplary of the first embodiment of the bracket 31 can be seen. In general, the present bracket may include three basic components, namely, a flexible component, implemented herein as plural flexible elements, that couples a rigid member to the motor assembly, with the
rigid member being connected to a support surface, and a flexible mechanical engagement between the rigid member and flexible elements to prevent vibration and noise from being transmitted from the motor assembly to the support surface. While the motor bracket 31 is shown in Figure 2, it is to be understood that the idler bracket 32 may be similarly constructed if desired.
The present invention critically recognizes that a significant increase of efficiency can be realized when the horizontal stiffness of the mounting system is lower and preferably much lower than the vertical stiffness. In this way, the present invention recognizes that the function of hanging the tubular motor assembly vertically advantageously is separated from the function of limiting its displacement in the vertical plane. Depending on the application, the function of limiting displacement in the vertical plane may be obtained using lateral guides acting on the fabric of the window covering itself without risking solid-borne vibration paths. Then, the horizontal stiffness is at least lower than the vertical stiffness. In non- limiting embodiments the ratio of horizontal and vertical stiffness is lower than 1 to 10.
Figure 2 shows that the bracket 31 may include a rigid member 37 that can be fastened to a fixture such as the mounting surface 30 by, e.g., threaded fasteners, nails, solvent bonding, welding, soldering, and the like. The non-limiting rigid member 37 may be made of metal or composite and may be L-shaped as shown, with a vertical portion 39 that is fastened to the mounting surface 30 and with a horizontal portion 38.
As shown in Figure 2, the horizontal portion 38 of the rigid member 37 is used to be attached to the top of the flexible mechanical connection, referred to herein as a "wire rope isolator", and to suspend the suspended mass 11 from the bottom bar 34, thus putting the wire rope
isolator in tension. The wire rope isolator typically includes a pair of elongated bars, namely, a top bar 33 and a bottom bar 34, which are connected with each other through the series of elongated springs 35 distributed longitudinally along each side of said pair of bars. The bottom bar 34 is attached to another rigid member 36 and may be made of metal or composite and may be L-shaped as shown where the horizontal portion attaches to the bottom bar 34 and the vertical portion attaches to the head 26 of the actuator 20, for respective coupling of the motor part of the bracket to the structural part of the bracket. The flexible spring in the form of a wire rope provides the only physical contact between the vibrating load (the motor and tube assembly) and the structural part of the bracket, which is attached to the underlying structure (wall, ceiling, window jamb, projection screen housing, etc.).
The elongated springs 35 may be separate but can also be parts of a same solenoid, a helicoidal spring having its axis perpendicular to the plane of Figure 2. In that case, each of the elongated springs 35 is a portion of half-loop of the solenoid.
In any case, it is to be understood that the embodiment shown in Figure 2 facilitates displacement of the suspended mass 11 in the horizontal direction perpendicular to the plane of Figure 2, than it does in the vertical direction, resulting from a lower stiffness at least in one horizontal direction than in the vertical direction.
Now referring to a non-limiting illustrative embodiment in Figure 3, an example of a second embodiment of the bracket 31 can be seen. In order to facilitate the comparison with the first embodiment shown in Figure 2, reference numerals of corresponding parts in Figure 3 are the same as the corresponding reference numerals in Figure 2, preceded by a "one" in the hundreds column.
A rigid member 137 is shown that can be fastened to a fixture such as the mounting surface 30 by, e.g., threaded fasteners, nails, solvent bonding, welding, soldering, and the like. The non-limiting rigid member 137 may be made of metal or composite and may be J-shaped as shown, with a horizontal portion 138 that is fastened to the mounting surface 30 and with a vertical portion 139 and then another horizontal portion 140 of the same rigid member.
As shown in Figure 3, the horizontal portion of the rigid member 140 is used to attach to the bottom of the flexible mechanical connection, referred to in Figure 3 as a "wire rope isolator", and to support the suspended mass 11 from the top bar 133, thus putting the wire rope isolator in compression. The wire rope isolator typically includes a pair of elongated bars, namely, a top bar 133 and a bottom bar 134, which may be connected with each other through the series of elongated springs 135 distributed longitudinally along each side of said pair of bars. The top bar 133 is attached to another rigid member 136 and may be made of metal or composite and may be S-shaped as shown where the top horizontal portion of the rigid member 136 attaches to the top bar 133 and its vertical portion attaches to the head 26 of the actuator 20, for respective coupling of the motor part of the bracket to the structural part of the bracket. The flexible spring in form of a wire rope provides the only physical contact between the vibrating load (the motor and tube assembly) and the structural part of the AVB bracket, which is attached to the underlying structure (wall, ceiling, window jamb, projection screen housing, etc.).
As in the previous embodiment, the elongated springs 135 may be parts of a same solenoid spring.
It will readily be appreciated that the horizontal stiffness of this embodiment is, at least in one direction, is lower than the vertical stiffness.
Figure 4 is a variant of the first embodiment shown in Figure 2. Figure 4 shows that the bracket 31 can include a rigid member 40 that can be fastened to a fixture such as the mounting surface 30 by, e.g., threaded fasteners, nails, solvent bonding, welding, soldering, and the like. The non-limiting rigid member 40 may be made of metal and may be L- shaped as shown, with a vertical portion 41 that is fastened to the mounting surface 30 and with a horizontal portion 42 defining a top surface 44. The top surface may be established by the rigid horizontal flange itself and/or by a pad 46 that is disposed thereon. The pad 46 may be rubber or other resilient material.
As shown in Figure 4, the horizontal portion of the rigid member 40 is formed with plural channels 48 that extend completely vertically through the horizontal portion from top surface to bottom, and a respective flexible element 50 extends through each channel 48. The channels can be sized such that the walls of each channel are slightly spaced from the flexible element 50 as shown. In the particular embodiment shown in Figures 4 and 5, each flexible element 50 includes a respective disk- shaped top stop 52 that is substantially orthogonal to the long axis of the flexible element 50 for resting against the top surface 44. The flexible elements 50 may be wire, or rubber or plastic strings, and in addition to being flexible may be resilient.
Accordingly, as shown in Figures 4 and 5 the flexible elements 50 depend downwardly from the rigid member 40 and are coupled to the tubular motor assembly, for example to a second rigid member 45 which is itself connected to the head 26 of the actuator 20 by solvent bonding,
fasteners, and the like to couple the tubular motor assembly to the mounting surface 30 while attenuating propagation of vibrations from the tubular motor assembly to the mounting surface. In any case, the flexible elements 50 are deformable in the two horizontal directions (indicated by arrows 54) and are guided by the channels 48 in the rigid member 40, but they are not attached to the rigid member 40 and indeed when the pad 46 is used the flexible elements 50 have no physical contact with any rigid portion of the bracket 31. Holes 49 may be formed in the pad 46 to allow a vertical displacement of the flexible elements 50.
Assuming that motor bracket 31 and the idle bracket are of the same type, three degrees of freedom of displacement of the suspended mass 11 are enabled, at least until contact with other elements:
Rotation around a vertical axis crossing the horizontal axis of the suspended mass 11 ,
Rotation (tilting) around the horizontal axis of the suspended mass
11 ,
Horizontal translation along the axis of the suspended mass 11 or, equivalently, rotation of the flexible elements 50 around their top stops 52 in a vertical plane containing the horizontal axis of the suspended mass.
For a given angular displacement, each of these rotations needs a torque to counterbalance the associated stiffness of the bracket 31. In fact, the bigger the power assembly, the higher the stiffness that is required, even if the goal is to limit its value. Then, an implicit relation exists between this stiffness and the size and mass of the powered assembly. And, as a consequence, such a relation exists between the above rotations and the rated torque of the motor.
In all embodiments of the invention, the torque value that is needed for an admissible rotation angle is lower or preferably much lower than the rated torque of the motor.
In the preferred embodiments, the torque giving a rotation of 5D is even lower than one tenth of the rated torque of the motor.
In a non-limiting embodiment the inner and outer (relative to the mounting surface 30) flexible elements 50 are slighting longer than the more central elements 50, with the center-most element 50 being shortest of all. Consequently, when the motor is deenergized, and when the fabric is fully wound around the tube 12, the top stop 52 of the center-most element 50 contacts the top surface 44, whereas the top stops 52 of the outer-most elements 50 do not, but rather are spaced above the top surface 44. In that embodiment, any convex shape of the top stops locus would be convenient. A parabolic law is a simple way to realize it.
When the reliable element 14 is at least partially unwound, the application point of the resulting weight moves in the direction of arrow 56. Then, the central elastic element is less or no more stressed, with the next elastic element bearing the weight. The whole suspended mass 11 rotates, as seen in Figure 5.
A simpler embodiment derived from figure 4 only contains one pair of flexible elements. In a low cost realization, they could be directly fastened to the horizontal portion 42.
Figure 6 shows an alternate bracket 60, which is a variant of the second embodiment, having a rigid member 62 defining a top surface 64. A metal movable suspension member 66 has bar-like or chain-like legs 68 connected to a second rigid member 65, which is connected to the head
26 of the actuator 20. This suspension member 66 includes a top piece 63 that is spaced above the top surface 64 of the rigid member 62. The top piece 63 may be parabolic as shown. Flexible elements in the form of coil or cylindrical springs 67 are disposed between the top piece 63 and the top surface 64 of the rigid member 62 as shown. The legs 68 may be rigid or flexible, and under no load only the center-most spring 67 need contact the top piece 63, or all springs 67 can be perpetually connected to both the top piece 63 and top surface 64. The arrows 69 represent the allowed tilt of suspended mass 11. If desired, the legs 68 may join the second rigid member 65 together under the head 26 of the actuator 20 to cradle the head 26.
Figure 7 shows a bracket 70 that is in all essential respects identical to the bracket 31 shown in Figure 4, with the following exceptions. Flexible elements 72 such as wire or other strong material (or indeed plastic string) are embedded in a resilient top pad 74 that is on a rigid member 76. The flexible elements 72 extend through respective channels 71 in the rigid member 76 and connect to the second rigid member 75, which is connected to the head 26 of the actuator, at the elevational centerline 56 of the suspended mass 11. In a no torque position, only the central flexible element 72 bears the weight. As in Figures 4 and 5, this role is shifted when the torque increases.
Figure 8 shows a bracket 80 in which the plural flexible elements are established by a fabric 82. The plural channels of the previous variants are replaced by one single channel 81. The fabric may be a cloth ribbon, which can also be rubber impregnated. In case of low weight of the powered assembly, a simple rubber (or equivalent) sheet may be used. In any case, the horizontal stiffness of the twisted sheet preferably should remain low, and more preferably very low, compared to the vertical stiffness (for instance a 1/10 ratio). The fabric 82 includes two rigid ends.
The upper end 83 is fixed on the upper surface of a first rigid element 86. Alternatively, it lays upon a pad 84, which is located on the upper surface. The lower end 87 is secured to a second rigid element 85. The head 26 of the actuator is connected to the second rigid element 85.
Figure 9 shows a bracket 90 in which the plural flexible elements are not exactly vertical but instead establish an "X" pattern between element pairs. The plural channels are replaced by one single channel 91. It can be appreciated that this embodiment can be derived from the embodiment of the figure 4 by rotating the suspended mass half a turn in the horizontal plane.
A combination of figures 8 and 9 would also give another embodiment that uses a ribbon, which both fabric axes are oriented at 45° apart from the vertical line.
In a simpler embodiment derived from figure 8 or 9 the channel is not used and the fabric and/or the elastic elements is/are directly fastened to the horizontal portion of the first rigid member (respectively 86, 96).