Patent Publication Number: US-7910849-B2

Title: Button mount for a lighting control

Description:
FIELD OF THE INVENTION 
     The present invention relates to lighting controls and more particularly to a button mounting system for a lighting control. 
     BACKGROUND OF THE INVENTION 
     Known lighting controls include an on/off mechanism having a button that actuates a momentary tactile switch when the button is pressed by a user. The on/off button of the Vareo® lighting control by Lutron Electronics Co., Inc. of Coopersburg, Pa. is located next to a slide actuator of a dimmer mechanism. Referring to  FIGS. 1 and 2 , the prior on/off button  10  of the Vareo® lighting control is shown separately from the lighting control along with flexible button supports  12  located at opposite ends of the button  10 . The button supports  12  are integrally molded with the button  10  from a thermoplastic material such as polycarbonate. 
     Each of the button supports  12  includes a tab  14  connected to one of the ends of button  10  and a pair of elongated legs  16  extending from opposite sides of the tab  14 . A pad  18  projects downwardly (with respect to the view of  FIG. 1 ) from each of the legs  16  for contact with an underlying support surface of the lighting control. Referring to  FIG. 2 , the pads  18  on the left extend further from the associated legs  16  than those on the right to provide for contact with different support surfaces (e.g., surfaces of a yoke and an adapter). 
     Referring to the rear perspective view of  FIG. 2 , a pair of retainer prongs  20  extend from a rear surface of the button  10  for snap attachment with the lighting control to limit unintended removal of the button  10 . Posts  22  extend from the rear surface of button  10  for contact with a pivoting hinge bar (not shown) of the lighting control. The hinge bar of the lighting control is adapted to contact the switch of the on/off mechanism to transfer actuating motions of the button  10  to the switch. 
     Each pair of legs  16  is adapted to flex in response to load applied to the button  10  to provide for a variety of button motions. Contact near the center of the button  10  results in substantially equal flexing of all of the legs  16  and uniform deflection of the button  10 . Contact adjacent one of the ends of the button  10  flexes the legs  16  adjacent that end causing the end to deflect while deflection of the opposite end of button  10  is minimal. Contact adjacent one of the opposite sides of the button  10  results in deflection of that side of the button  10  with respect to the opposite side. 
     The use of polycarbonate provides for integral molding of the button  10 , button supports  12 , retainer prongs  20  and posts  22  from the same material. In addition to providing for integral molding, polycarbonate provides hardness characteristics desired for actuator buttons. The integral construction of the button supports  12  from the same material as the button  10 , although facilitating fabrication, results in less than ideal operating conditions for the flexing button supports  12 . As described above, the legs  16  of the button supports  12  contact the yoke of the lighting control. Heat is transferred to the legs  16  of the button support  12  from the yoke during operation of the lighting control. Such heating of the polycarbonate and repeated flexing of the legs  16  can lead to fatigue failures at the junctions between the legs  16  and the tabs  14 . 
     SUMMARY OF THE INVENTION 
     According to one aspect, the present invention provides a system for mounting a button having opposite ends. The mounting system comprises first and second spring elements each coupled to the button and located adjacent one of the opposite ends of the button. Each of the spring elements has a serpentine portion. The mounting system may further comprise a base adapted to be supported by a surface. Each of the spring elements is coupled to the base such that the spring elements are supported at a distance from the surface. 
     According to another aspect of the invention, an assembly for a control unit comprises a button having opposite ends, and first and second spring elements each coupled to the button and located adjacent one of the opposite ends of the button. Each of the spring elements includes a serpentine portion adapted for multiple degrees of freedom to provide varying actuating motions of the button. 
     Further the switch assembly comprises a switch and a hinge bar. The hinge bar is disposed between the button and the switch and is supported for pivot about an axis. The hinge bar is arranged to actuate the switch in a uniform actuation motion in response to any one of the actuating motions of the button. 
     According to one aspect of the invention, an assembly for a control unit having a yoke is provided. The assembly comprises a button defining opposite ends, and a spring plate comprising a metal secured to the button and supporting the button at a distance from a front surface of the yoke. The spring plate includes first and second spring elements each located adjacent one of the opposite ends of the button and adapted to provide multiple degrees of freedom of movement for the button. 
     According to yet another aspect of the invention, an actuator assembly comprises a button having opposite ends, and first and second spring elements coupled to the button and located adjacent the opposite ends of the button. Each of the spring elements includes first and second legs extending substantially parallel to each other in side-by-side fashion. The legs of each of the spring elements are connected to each other at an end of the legs and are substantially co-planar with each other when the spring element is in an unloaded neutral condition. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a prior art button for a lighting control; 
         FIG. 2  is a rear perspective view of the prior art button of  FIG. 1 ; 
         FIG. 3  is a perspective view of a lighting control according to the invention including an on/off mechanism having a button; 
         FIG. 4  is a perspective view of the lighting control of  FIG. 1  with a faceplate of the lighting control removed to show a mount system for supporting the button of the on/off mechanism; 
         FIG. 5  is a front perspective view of the button and mount system of  FIG. 2 , shown removed from the lighting control; 
         FIG. 6  is a rear perspective view of the button and mount system of  FIG. 5 ; 
         FIG. 7  is a front exploded perspective view of the button and mount system of  FIG. 5 ; 
         FIG. 8  is a rear exploded perspective view of the button and mount system of  FIG. 5 ; 
         FIG. 9  is a perspective view of a hinge bar and switch of the on/off mechanism of the lighting control of  FIG. 1 ; and 
         FIGS. 10A through 10C  illustrate varying degrees of freedom of movement for the button of the on/off mechanism provided by the mount system of the lighting control of  FIG. 3 . 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Referring to the drawings, where like numerals identify like elements, there is shown in  FIGS. 3 and 4  a lighting control  100  according to an exemplary embodiment of the invention. The lighting control  100  includes an on/off mechanism  102  having a button  104  and a dimmer mechanism  106  having a slide actuator  108  located next to the button  104 . The button  104  is generally rectangular including opposite sides  110  defining a length (along the Y-axis) and opposite ends  112  defining a width (along the X-axis). As described below in greater detail, the lighting control  100  includes a button mounting system that provides multiple degrees of freedom of movement for the button  104 . This arrangement provides for varying motions of the button  104  depending on the portion of the button  104  contacted by a user to actuate the on/off mechanism  102 . The differing motions of the button  104 , however, are transferred to an underlying hinge bar  114  ( FIG. 9 ) to provide for a uniform actuating motion and a consistent actuation of the on/off mechanism  102 , as described below. As also described below, the present invention provides a construction that facilitates material selections for optimal fabrication and operation of the on/off mechanism  102 . Although the on/off mechanism of the present invention is depicted as part of lighting control  100  also having dimmer mechanism  106 , it should be understood that a dimmer mechanism is not required. It should also be understood that the on/off mechanism of the invention is not limited to controls for controlling light and has application to controls for controlling other loads such as a fan for example. 
     The lighting control  100  includes a faceplate  116  having a rectangular aperture  118  in which the button  104  and slide actuator  108  of the on/off and dimmer mechanisms  102 ,  106 , respectively, are presented to a user. Referring to  FIG. 4 , the lighting control  100  is shown with the faceplate  116  removed. The lighting control  100  includes a faceplate support member  120 . Preferably, the faceplate support member  120  is secured to an underlying yoke  124  of the lighting control  100  by fasteners (not shown) at locations  126 . The faceplate  116  and faceplate support member  120  are adapted to provide for snap attachment of the faceplate  116  to the faceplate support member  120 . Preferably, the faceplate support member  120  defines peripheral lips  122  engaging corresponding notches defined by the faceplate  116 . Alternative snap attachment means could be used such as projecting elements on a rear surface of the faceplate  116  received by openings defined by the faceplate support member  120 . This type of faceplate, sometimes referred to as a “screwless” faceplate, having an underlying support member to which the faceplate is releasably attached, is well known and, therefore, no further description is necessary. An example of such a faceplate is disclosed in U.S. Pat. No. 4,835,343, the entirety of which is hereby incorporated by reference. 
     The button  104  of on/off mechanism  102  is part of an assembly  128  also including a mount system for the button  104 . The assembly  128 , which is shown separately in  FIGS. 5-8 , includes a spring plate  130  secured to button  104  to move with button  104  during actuation of the on/off mechanism as described below. The assembly  128  also includes a support base  132  located between the spring plate  130  and the yoke  124 . As shown in  FIG. 4 , the support base  132  supports the spring plate  130  at a distance from the yoke  124 . This arrangement provides spacing between a front surface  134  of yoke  124  and spring plate  130  to limit contact that would otherwise occur between opposite end portions of the spring plate  130  and the yoke  124 . 
     Referring to  FIGS. 5 through 8 , the spring plate  130  includes a rectangular center portion  136  secured to the button  104 , end portions  138  secured to the support base  132  and defining opposite ends of the spring plate  130 , and serpentine spring elements  140  located between the center portion  136  and each of the end portions  138 . 
     Referring to  FIGS. 6-8 , the center portion  136  of spring plate  130  includes a relatively large circular opening  142  and a plurality of relatively small circular openings  144 . The opening  142  is adapted for receipt of a cylindrical projection  146  on a rear surface of button  104  located approximately midway between opposite ends of the button  104 . The cylindrical projection  146  is located on the rear surface of button  104  at a thin-wall portion of the button  104 . The cylindrical projection  146  is adapted for receipt of illumination from a lamp (e.g., a neon bulb or a light-emitting diode) such that light from the lamp is visible through the thin-walled portion of the button  104  to a user of the lighting control  100 . The openings  144  are arranged for receipt of cylindrical posts  148  on the rear surface of button  104 . As shown in  FIG. 6 , the posts  148  of button  104  are preferably flattened (e.g., by heat and compression) following their receipt within the openings  144  of spring plate  130 . The flattening of the posts  148  widens the posts  148  in a rivet-like fashion to secure the button  104  to the spring plate  130 . The center portion  136  of spring plate  130  also includes a pair of square openings  150  arranged to accommodate posts  152  on the rear surface of button  104  that are located adjacent the opposite ends of the button  104 . As described below, the posts  152  of button  104  provide for contact between the button  104  and the underlying hinge bar  114  of the on/off mechanism  102 . 
     As shown in  FIG. 6 , the rectangular center portion  136  of spring plate  130  is elongated to provide a length for the center portion  136  that is approximately equal to a length of the button  104  between ends  112  of the button  104 . This arrangement locates the serpentine spring elements  140  adjacent the ends  112  of the button  104  as shown. The center portion  136  of spring plate  130  has a width, as shown, that is sufficient to provide sufficient space for the openings  142 ,  144 ,  150 . The precise dimensions of the center portion  136  of spring plate  130  are not critical, however, and could vary from those depicted. 
     Referring to  FIGS. 5 and 7 , each of the end portions  138  of spring plate  130  includes a pair of circular openings  154  arranged for receipt of cylindrical posts  156  of support base  132 . Similar to the posts  148  of button  104 , the posts  156  of support base  132  are preferably flattened following receipt of the posts  156  by the openings  154  thereby widening the posts  156  in a rivet-like fashion to secure the spring plate  130  to the support base  132 . 
     The support base  132  includes a pair of pedestal portions  158  arranged at opposite ends of the support base  132  in substantially parallel fashion for supporting the end portions  138  of spring plate  130  at a distance from an upper surface  134  of yoke  124 , as shown in  FIG. 4 . The support base  132  also includes an elongated side bar  160  extending between ends of the pedestal portions  158  such that the support base  132  is generally C-shaped. The support base  132  includes a notch recess  162  formed in a lower surface that extends along the length of the side bar  160 . The notch recess  162  in the lower surface of the support base  132  is arranged to receive a lower wall  166  of a retainer channel  164  defined by the faceplate support member  120 . Arranged in this manner, a portion of the support base  132  will be captured within the retainer channel  164 . The depicted support base  132  also includes notches  168 ,  170  in lower surfaces of the side bar  160  and pedestal portions  158 , respectively, to accommodate underlying elements (not shown) of the lighting control  100  projecting from the upper surface of the yoke  124 . 
     As shown in  FIGS. 5-8 , the button  104  includes a pair of retainer prongs  172  located at one side of the button  104  opposite the side bar  160  of support base  132 . The retainer prongs  172  of button  104  are adapted for snap-type receipt within an interior of the lighting control  100 . As described above, the spring plate  130  is secured to the support base  132  and the button  104  is secured to the spring plate  130 . As should therefore be understood by those skilled in the art, the capture of the support base  132  within the retainer channel  164  of faceplate support member  120  and the snap receipt of the retainer prongs  172  of button  104  within the interior of lighting control  100 , serves to limit unintended removal of the assembly  128  from the lighting control  100 . The retainer prongs  172 , however, are adapted to permit relative movement between the button  104  and fixed portions of the lighting control  100  desired for actuation of the on/off mechanism  102 . 
     Each of the serpentine spring elements  140  of the spring plate  130  includes first and second legs  174 ,  176  extending substantially parallel to each other in a close side-by-side fashion. The legs  174 ,  176  are connected to each other at one end of the legs  174 ,  176 . The legs  174 ,  176  are also connected to the center portion  136  of the spring plate  130  and to one of the end portions  138 , respectively, at an opposite end of the legs  174 ,  176 . The legs  174 ,  176  of each serpentine spring element  140  are elongated to extend substantially parallel to the end portions  138  of spring plate  130  and substantially parallel to ends  178  of the center portion  136 . Arranged in this manner, the serpentine spring elements  140  are located within relatively narrow spaces between the ends  112  of button  104  and the pedestal portions  158  of support base  132 . Also, the legs  174 ,  176  of each serpentine spring element  140  are substantially co-planar with each other when the spring plate  130  is in a neutral condition associated with an unloaded state for button  104  (i.e., in the absence of a force applied to the button by a user of the lighting control  100 ) because they are part of a plate. Therefore, the spring elements  140  also desirably occupy only a limited space in a transverse direction with respect to button  104  (i.e., along the Z-axis in  FIG. 4 ). 
     The above-described construction of the serpentine spring elements  140  allows for deflection (along the Z-axis in  FIG. 4 ) of the center portion  136  of spring plate  130 , and button  104  secured thereto, with respect to the end portions  138  of spring plate  130  secured to support base  132 . Such Z-axis deflection of the center portion  136  of spring plate  130  would occur, for example, when the button  104  is contacted by a user in a central location on button  104 . 
     The construction of the serpentine spring elements  140  also provides for rotation (about the Y-axis in  FIG. 4 ) of the center portion  136  of spring plate  130 , and button  104  secured thereto, with respect to the end portions  138  of spring plate  130  secured to support base  132 . Such rotation (i.e., twisting motion) of the center portion  136  of spring plate  130  would occur, for example, when the button  104  is contacted by a user adjacent one of the sides  110  of button  104 . As shown, the serpentine spring elements  140  are preferably reversed with respect to each other such that the legs  174  are connected to the center portion  136  of spring plate  130  adjacent opposite sides of the center portion  136 . The reversed arrangement of the serpentine spring elements  140  in this manner facilitates a uniform torsional reaction of the spring plate  130  to a Y-axis rotation of button  104  regardless of the direction of motion (i.e., regardless which side  110  of button  104  is contacted). 
     Referring to  FIG. 9 , a portion of the on/off mechanism  102  of lighting control  100 , including hinge bar  114 , that underlies the button  104  is shown separated from the lighting control  100  to facilitate description. The on/off mechanism  102  includes a switch  180  supported on an upper surface of a board  182  (e.g., a printed circuit board). As shown, the hinge bar  114  is generally C-shaped including a center arm  184  and opposite end arms  186 . The hinge bar  114  includes a hinge post  188  adjacent a terminal end of each of the end arms  186 . The hinge posts  188  on the end arms  186  are pivotably supported within the interior of the lighting control  100  by upstanding elements (not shown) of the lighting control  100  such that the hinge bar  114  pivots about an axis that extends through the hinge posts  188 . 
     As shown, an intermediate portion of the center arm  184  of hinge bar  114  is tiered to define upper surfaces at locations  190  that are arranged for contact by the posts  152  on the rear surface of button  104 . The contact between the posts  152  of button  104  and the locations  190  on hinge bar  114  transfers one of the various actuating motions of button  104 , described further below, into a pivoting motion of hinge bar  114  about the hinge posts  188 . A contact pin  192  extends from the hinge bar  114  adjacent an intersection between the center arm  184  and one of the end arms  186  to contact the switch  180 . As should be understood, this construction locates the switch  180  closer to one of the opposite ends  112  of button  104  than the other. The intermediate action of the pivoting hinge bar  114  allows the switch  180  to be located outside of an underlying footprint boundary on the board  182  defined beneath the button  104  by the perimeter of the button  104 . 
     The hinge bar  114  also includes rectangular posts  194  in the intermediate portion of the center arm  184  adjacent the contact locations  190 . Referring again to  FIG. 6 , the rectangular openings  150  in spring plate  130  that receive the contact posts  152  of button  104  are oversized with respect to the contact posts  152  such that a portion of the opening  150  is not occupied by the post  152 . In this manner, space is provided in each opening  150  next to the post  152  to accommodate one of the rectangular posts  194  of the hinge bar  114  for contact with a rear surface of button  104 . This provides for alternative contact points between the button  104  and the hinge bar  114  (e.g., either between the button posts  152  and contact locations  190  of hinge bar  114  or between the posts  194  of hinge bar  114  and the rear surface of button  104 ). 
     As discussed above, the on/off mechanism  102  is constructed such that the switch  180  is located closer to one end of the button  104  than the other and possibly outside of a boundary defined by the perimeter of the button  104 . Notwithstanding such non-centralized location of the switch  180  with respect to button  104 , and further notwithstanding the various motions permitted for the button  104 , the intermediate action of the hinge bar  114  serves to transfer any button motion into a single, uniform, actuating motion of the switch  180 . 
     Exemplary actuating motions for button  104  are illustrated in  FIGS. 10A through 10C . Referring to  FIG. 10A , a user may contact the button  104  adjacent one of the opposite sides  110  of the button  104  to apply an actuating force, shown as F s . As described above, the construction of the serpentine spring elements  140  of spring plate  130  provides for a rotational movement of button  104  about the Y-axis (or longitudinal axis), in a direction represented by R y . The spring plate  130  reacts torsionally to the rotational movement to apply a biasing force tending to return the button  104  to a neutral (i.e., unloaded) position as shown in the figures. As should be understood by one skilled in the art, an application of an actuating force to the opposite side  110  of the button  104  from that shown in  FIG. 10A  would result in a rotation of button  104  in an opposite direction. As described above, the construction of the spring plate  130  provides for a uniform torsional response of the spring plate  130  regardless of the direction of rotation (i.e., regardless of which side of the button  104  is contacted by a user). 
     Referring to  FIG. 10B , there is shown another exemplary actuating motion for button  104  provided by the assembly  128 . A user may contact the button  104  adjacent one of the ends  112  of button  104  to apply an actuating force, F e , to the button  104 . As illustrated, the construction of the serpentine spring elements  140  located adjacent both ends of the spring plate  130  results in a deflection (along the Z-axis), shown as d e , of the end  112  of button  104  that is contacted. The opposite end  112  of button  104 , which is remotely located from the applied load, will experience only a minimal deflection at most. The resulting motion of the button, therefore, is substantially that of a rotation of the button, shown as R e , about a transverse axis defined by the end  112  of button  104  opposite the end  112  at which the load is applied. As should be understood, a similar load applied to the opposite end  112  of button  104  from that shown (e.g., a load of F e  applied to the near end  112  of button  104  in  FIG. 10B ) will result in a deflection of d e  at the near end  112  of button  104  and a rotation of R e  about a transverse axis defined by the far end  112  of button  104  in  FIG. 10B ). 
     Referring to  FIG. 10C , there is shown another exemplary actuating motion of the button  104  provided by the assembly  128 . A user may contact the button  104  in a central location (i.e., substantially midway between the opposite sides  110  and substantially midway between the opposite ends  112 ). The resulting motion of the button  104 , as shown, is that of substantially uniform deflection, d c , throughout the button. 
     Preferably, the button  104  and the support base  132  are both made from a polymer material. Preferably, the polymer material for the button  104  is a thermoplastic material such as polycarbonate. The use of a thermoplastic material, and an associated molding process, facilitates the fabrication of the button  104  and the support base  132  each of which includes numerous formations (e.g., posts, prongs, recesses, etc.). In addition, such materials are desirable for buttons for other reasons such as hardness, scratch-resistance, surface textures, etc. 
     Preferably, the spring plate  130  is made from a metal such as stainless steel. As should be understood, metals are desirable for flexing spring elements such as spring plate  130  because they possess favorable material properties (e.g., stress/strain characteristics, ductility, etc.). In addition, flexing spring elements of metal tend to retain these desired characteristics even when operating at elevated temperatures. For example, metal has less tendency to creep or become brittle compared to other materials. The use of metal for the spring plate  130  facilitates manufacture because the spring plate  130  may be formed from a plate or sheet of metal (e.g., in a stamping process). 
     The construction of assembly  128  of the present invention, therefore, having flexing spring elements formed from a different material than the button, provides for optimization of the material properties as well as the fabrication of both the button and the button mounting system. 
     The foregoing describes the invention in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial modifications of the invention, not presently foreseen, may nonetheless represent equivalents thereto.